GPR Robot Building - Dartmouth Engineering School

More Yeti Press

2011-11-03T15:52:00.004-04:00

More links to news reports on Yeti:

Scientific American: Harnessing Robots to Study Inaccessible Arctic
MSNBC: Rover Goes For Test Drive Around Polar Regions

Crevasse Detection: what to do when you don't have ice

2011-10-26T13:19:00.004-04:00

The end of summer and start of fall has proved a tumultuous time for Yeti. The shortage of funds and lack of ice breakers means Yeti will not be allowed to go to Antarctica for the Traverse, though he has picked up a moonlighting gig at South Pole Station. The old, buried station seems to be giving tractors a rough time, and Yeti will do a few grid searches with his GPR to locate pipes, empty spaces, and the like before new construction begins.

Due to another set of unfortunate turns, Yeti may not be able to go on any CRREL sponsored traverses to Antarctica or Greenland for the purpose of crevasse detection, so he is currently searching for other venues to prove himself. In the meantime, what does a Polar robot do without snow and ice? The answer, surprisingly enough, is dry, hot sand! It turns out that very dry sand has similar electrical properties as snow and ice, and it's possible to build a scale model of a crevasse in the lab.

So, all Yeti needs is a nice big space to build a huge sandbox. The crevasse itself can be modeled with good old fashioned polystyrene, which has the same electrical properties as air! We'll make an inverse "mold" of a crevasse with polystyrene in a wedge shape and place it in a large container (dumpster, swimming pool, pit, etc), and pour in the sand. To create striations we can intersperse some ply-wood or drywall layers.

The problem with scale models for GPR is a need for different radar frequencies. Lower frequency radio waves emit less power, but penetrate much deeper. High frequency pulses give off lots of power, but their depth penetration is shallow. If our model is smaller than a real crevasse (it better be; some crevasses penetrate deeper than 50 meters!), we don't want the GPR energy radiating deeper than our model, because then we will get signals from the floor, the building foundation, and anything in-between! We currently use 400 MHz antennas with a SIR-3000, which can image 25 meters deep in ice! We'll need to switch to a much higher frequency antenna, preferably in the giga-Hertz range. Common frequencies are 2.1 and 2.6 GHz. Then, we can scale a crevasse by at least a factor of 5. A 12.5 meter deep crevasse then could be modeled with a 2.5 meter deep polystyrene wedge buried in dry sand.

Yeti and I will continue to be resilient in the face of adversity. Stay tuned.

Intro to Crevasse Detection

2011-08-21T09:18:00.007-04:00

I thought I would provide some more background on my work in crevasse detection. Suk Joon and Tom Lane did a great job chronicling their efforts at Summit to equip Yeti with an instrument sled and control code. However, sample acquisition is only one of Yeti's many capabilities. His other profession, of course, is crevasse detection.

What is Crevasse Detection and Why Should We Care?
Crevasses are the ice analogues of crevices in rocks. They are cracks in the glacier. Crevasses can be constrained to the surface layers, consisting of snow and firn, or can penetrate as deep as the glacier base. I am concerned primarily with surface crevasses in the top 12 meters of glacier firn. Firn is a term for a medium density layer of snow in between harder, deeper ice and softer surface snow. Crevasses in the firn and snow layers are dangerous to vehicles traveling across the ice sheet. They are particularly dangerous because they are invisible to the naked eye: the winter accumulation and storms result in the formation of a snow bridge across the crevasse mouth. Since snow is a very plastic material at low strain rates, the bridge is eventually able to thicken enough to hold several meters of snow over it's opening, rendering it invisible on the surface. If you were to look across the expanse of a crevasse field on a glacier in the winter, you would not see a single thing but uninterrupted, white cold beauty. It almost beckons you to bound forward in delight, only to fiercely swallow you up in one gulp. The snow bridge strength is rarely known, and our only insight into its thickness is a ground penetrating radar investigation.

Here are two really good but really creepy pictures of a hidden crevasse, before and after it was driven over by a tractor.

This is a picture from inside the tractor cab, looking forward. The black flags are markings for known crevasses, so the tractor was driving in another direction trying to find a way through.

This is a picture from the back of the tractor cab. You can see where the tracks are interrupted by the big hole. After the tractor drove over it, the snow bridge crumbled under the weight of the tracks, and the crevasse opened up. If the bridge had broken just one second earlier, the entire rear end would have fallen into the crevasse. This is what is known as an unpleasantly close call.

Yeti's Next Phase: Autonomous Crevasse Detection

2011-08-18T18:29:00.006-04:00

As 2011 closes, Yeti has made some serious improvements in both his behavior and abilities. Our exiting hero, Suk Joon is off to serve his two years in the military. We're not sure where Tom is, but we hope to see him soon, and thank him for all his work on Yeti for his thesis. Danny Dumond has also woefully departed, leaving the last remnants of terrain classification and Yeti for some other at some other time. Danny has successfully started a position at Aptima, a government defense contractor. She will be doing research and apparently lots of proposal and grant writing. Good thing Dr. Ray isn't there to correct your papers! (just joking, my humblest apologies, it's all in good fun). Good luck, our Departed Danny Dumond!

And now, I suppose, our dear Yeti and I are left to bond, hopefully without too much struggle. Yeti's next phase is now my task and thesis: A Robotic system for automatic crevasse detection using ground penetrating radar. Yeas or nays on that as the be-all end-all title of said thesis?

Yeti's newest capabilities include more complex search designs (rosettes and grids), real-time interface with the ground penetrating radar, a SIR-30 from Geophysical Survey Systems. And last but not least, the pièce de résistance, real-time classification of GPR scans for detecting buried crevasses. Of course, a huge thank you to GSSI for their enthusiastic and generous help. They supply us with Ground Penetrating Radars that Yeti tows on his backside. Here's a simplified diagram of his new get-up.

Some sadder news: currently the US is at a stand-still in terms of its government-funded research and logistics in Antarctica. This is because the US Antarctic Program (USAP) does not actually own a functioning ice-breaker. We've been using kind Sweeden's, but this year they need them all for various reasons, and the US is up an ice stream without an ice-breaker, literally, pun intended, etc. What other frozen countries up there might be able to lend us a hand? Ah yes, privyet Russiya. We have asked to borrow just a teensy one, since they have so many and all, but there's a bit of a problem. It seems that the Antarctic Treaty does not allow nuclear weapons in the South Pole, and does not particularly expire. And of course, you guessed it, Russia's ice-breakers have nukes on them. Sigh. The upshot of all that is, that those high up above are trying to come to some sort of agreement on the unfortunate mess. Here's the link to the New York Times article.

This problem is especially disconcerting to Yeti, because he is currently being funded by stealthily signing himself up for Heavy Traverses across Greenland and Antarctica funded by the USAP and the US Office of Polar Programs (OPP). But, he maintains a positive attitude, and I look forward to his training and development! Next I'll try to post a movie of the crevasse classification system I've developed! So far, I've gotten up to 92% accuracy with Support Vector Machine and Logistic Regression models trained on actual crevasse GPR data from Antarctica and Greenland.

Yeti Press

2011-08-05T19:23:00.004-04:00

Wow looks like people are taking a liking to our dutiful friend Yeti!

Newspapers
New York Times
Discovery
Popular Mechanics
The Dartmouth
E&E Publishing

Blogs and Such
http://www.autonomousrobotsblog.com/yeti-robot-avoids-snow-traps/
http://www.popularmechanics.com/technology/engineering/extreme-machines/yeti-and-cool-robot-the-rovers-tough-enough-to-explore-greenlands-ice-sheet
http://www.gizmowatch.com/entry/yeti-robot-detects-polar-crevasses-advance-transportation/
http://www.ecofriend.com/entry/yeti-battery-powered-robot-helps-detecting-crevasses-ice-landscapes/

Here are more links to related pages!
Photos
Bio

Success

2011-07-21T19:31:00.003-04:00

After the many flight delays and cancellations yesterday, Suk Joon was finally able to fly in this morning. Immediately following lunch we got straight to work. Suk Joon tested the various stopping methods in the new instrument laptop code and was able to get all of them working.

Due to the favorable weather conditions, we decided to do a full test. We set a course of points 50-150m apart from the north end of camp and moving north east. During the test the snow ranged from very hard(<1 of boot sinkage) to soft (>6 in of boot sinkage). Yeti was able to complete the first 13 waypoints, but the thick snow at the 14 point cause Yeti to go in circles around the point, never getting close enough to register that it was at the point.

Yeti driving off into the wild on its autonomous journey

After dinner we attempted to do a nearly identical run. The cold weather helped firm up the snow and Yeti was able to reach the waypoints after circling them several times.

The flight out of Summit is still scheduled for the 23rd so we will start packing up after breakfast tomorrow. This trip has gone by way too quickly. I've just started to get use to the altitude and almost all of Yeti's mechanical problems have been solved. I'm definitely going to miss Quentin's wonderful cooking, but a nice warm room will be a welcome change after a week in a freezing cold tent.

Day 7 the best day

2011-07-21T19:28:00.004-04:00

Yeti traveling autonomously doing square wave pattern

The robot circling near the waypoint when the turning effort is saturated due to the resistance of deep snow.

Tom trying to deflate tire in order to reduce slippage and ground pressure.

View of the Summit Camp from far away

Today was the best day in many ways. First of all, I was lucky enough to get back to the Summit after all the complication for past 4 days (flight cancellation, bad weather, and administrative approvals...).

We ran two long range autonomous mode tests, which were both successful. The first run was about 2.5km run. Yeti performed almost perfectly until 14th waypoint out of 20th waypoint. Then, the snow got too soft, and Yeti was not able to turn efficiently. As a result, when we got closer to Yeti, Yeti was making a circle around 14th waypoint without being able to go through this waypoint due to saturation of turning effort. We had to pull the robot out of deep snow in order for the robot to continue this long autonomous run. It took about 1 hours and 20 mins to get to 16th waypoint due to circling problem, and by this time, the voltage of the battery was too low for Yeti to move on. However, we definitely got a confirmation of how Yeti can travel for about 2km by itself. Also, the first test showed us that we need to prevent Yeti to go too deep into the snow.

The second long range test was little bit shorter because we wanted the robot to have enough battery power left to come home by itself. It was about 1km run. Even after deflating tire, we still ran into the problem of the saturation of turning effort in deep snow. We decided take of UNH package which was weighing down the robot too much. After this, the robot had much easier time traveling through deep snow and accurately hitting each waypoint. In 50 mins, the robot completed the 1km run, and successfully came back home autonomously.

The two tests show that we either have to increase the robot's capacity to turn or to decrease the accuracy of waypoint following. These will prevent the robot from circling around the waypoint without going through it. Also, we know that the weight of the instrument package can be a great obstacle in a deep snow reducing the robot's ability to turn.

Also, we carried out quick test for each stopping mode using the instrument laptop, using a short 5 point autonomous run. The results were very successful. All 3 stopping modes were carried out perfectly, suggesting that the robot will be able to perform stops configured to the need of various instruments.

Although we did not have time to travel all the way to the other side of the skiway to do an accurate plume experiment, we were very satisfied by the robots ability to carry out a long range autonomous travel as well as stopping patterns.

Bad Weather

2011-07-20T09:22:00.002-04:00

A huge snow storm rolled in today. Summit has received several feet of snow and the powder is really soft. Walking outside of the camp I've been sinking down to my knees at points. I attempted to take Yeti out this morning and as soon as Yeti passed the berms on the north end of the camp, it sunk past its motor housings. With the continued snow and warm weather coming up, I will be unable to operate Yeti off base for several days.

Days 4-5

2011-07-20T09:20:00.001-04:00

Day 4- Brandon and I took Yeti off base for the first time. We strapped Yeti to a sled and took a pair of snowmobiles west of the skiway. I entered the wrong coefficients for the autonomous control so Yeti struggled to make the turns fast enough. The snow was quite deep and Yeti's tires would dig down until the motor housings touched the snow, but Yeti never got stuck. Travel was quite slow because the tires were slipping.

Later in the day, I took Yeti out to the north of camp, but Yeti got stuck in the snow drifts on the north end of camp. I took manual GPS measurements of a safe path through the berms for future travel.

Day 5-Took Yeti out to the Northeast of the camp, parallel to the skiway. The IGERT students arrived today and several of them volunteered to help me. After fixing the control coefficients Yeti appeared to be running perfectly. About 500 meters away from the base, Yeti got stuck and managed to dig itself in. I inspected the spot where Yeti got stuck and could find nothing different at that point. Yeti was still slipping, especially when turning. To retrieve Yeti I towed a group of IGERT students behind a snowmobile. I followed behind Yeti as one of the other students drove Yeti manually using a laptop. We lost radio contact with Yeti briefly and nearly ran into the highly explosive JATO engines, the only obstacle on the north end of camp.

After returning, I measured the air pressure in the tires and found one tire at 30+psi and the others around 10psi. I took air out of the tires until they were all at about 4psi. This should prevent some of the slipping, but I haven't had a chance to test this.

Notes on Summit and the Project

2011-07-19T19:13:00.003-04:00

Summit is a camp at the peak of the Greenland ice sheet. The camp is located at about 10,500 feet elevation and the temperature stays below freezing year around. The temperature has generally ranged between -20F and 20F. Various scientific groups do a variety of research on the snow, air, and ice in the area. Food is prepared by the camp chef who has cooked a variety of delicious meals from curry to gumbo.

This summer's deployment to Greenland has two main purposes. First, it is a test of the autonomous control system on Yeti to ensure it can follow complicated paths as required by scientists. Second, Yeti is collecting surface roughness data for Dartmouth researcher Mary Albert and particulate matter data for UNH researcher Jack Dibb.

The overall goal of the Cool Robot project is to create an autonomous robot platform which can be used with a variety of scientific packages. Yeti, along with the solar powered Cool Robot can be programmed with GPS coordinates and sampling procedures and allowed to collect data with little or no user interaction.

Days 3 and Pictures from Day 1 and 2

2011-07-19T17:33:00.010-04:00

pictures taken on the flight from Kanger to Summit

Photos taken by Suk Joon of the area around the base at Kanger

The KISS building we lived in at Kanger

The C130 which transported us to Summit

unloading the transport

Our work space in the Science Operations Building

arriving at Summit

Tuna melts for lunch

Manually driving Yeti behind the base

The tents we sleep in. They stay relatively warm, but my water bottles are partially frozen when I wake up in the mornings.

Suk Joon had to leave due to Altitude sickness so I've recruited other students up at summit to help me.

7/17 - Ran a 250m long test using a square wave going north of the Science Operations Building. The sensor package was assembled on the sled with the Trimble GPS antenna going between the instrument laptop and UNH's C.R.A.P. Rigid poles were used over ropes to prevent the instrument package from flipping and to allow Yeti to backup. Ropes were used to attach the poles to the sled to allow for some give between the robot and the sled.

The control code worked perfectly and the robot turned with almost no oscillation. Although this test was conducted entirely in base, data was still collected with the two particulate filters and the GPS.

A group of high school students from Greenland, Denmark, and the USA came to Summit for several days. I gave a short demo of how Yeti works and convinced several of them help me take Yeti on several runs

Second Day at the Summit

2011-07-19T11:48:00.002-04:00

Today, we decided to fix the problems that we found yesterday.

In the morning, we first worked on the connection between the sled and the robot. We first changed the connection from the pipe/ aluminum bracket to the pipe/ rope configuration. This hammock configuration enabled the sled to be offset from the robot so that the turning momentum of the robot was not so big. Furthermore, we shorten the pipe so that the distance between the robot and the instrument sled was not so big. After this change, the turning of the robot was significantly faster and smoother.

In the afternoon, I had to take a break due to altitude sickness. While I was taking a break, Tom worked on setting up of Trimble GPS. By the end of the afternoon, Tom configured GPS successfully.

In the evening, we did several autonomous runs with the instrument sled connected to the robot. Yeti completed the runs successfully even with more complex patterns of square wave. However, the robot again failed to stop after the completion of the autonomous run.

Late at night, I worked on the dynamic C code and the driving java code to fix this problem in the autonomous run. Unfortunately, I did not get a chance to test to code before I had to fly back to Kanger for altitude sickness.

First day at the Summit

2011-07-19T11:39:00.004-04:00

After 2 hour flight in National Guard's Cargo Airplane, we finally arrived at the Summit. After a quick lunch, we went to straight to work.

After unpacking all the crates, we first decided to test out Yeti's autonomous run. Thankfully, the autonomous run was successful after tweaking the coefficients of the Proportional Integral Control in the driving logic.

Then, we decided to connect the instrument sled to Yeti to see whether Yeti is functional while towing the sled. When we connected the sled with the pipe that was used to connect GPR, we found that the turning momentum of the robot + sled was too great. When we manually controlled the robot to turn, the robot was barely turning even at the highest speed differential between the left and the right wheels. Therefore, we decided that we should shorten the distance between the sled and the robot as well as make the connection more flexible instead of using pipe and aluminum bracket.

Also, during the autonomous run, the robot sometimes restarted automatically the autonomous run after finishing the first run. This seems to be an error in the dynamic C driving code that needs to be fixed for tomorrow.

In the evening, we demonstrated the robot's autonomous run to NSF's media group and journalists from AP and popular mechanics. Then, we did interviews with them as well.

Last Day

2010-10-30T06:09:00.001-04:00

Despite my best efforts, today is the day I have to leave McMurdo and return to the real world. It's been an unbelievable experience so far, but after three short-yet-long weeks on the ice, it's time to head back home. In every respect, this trip has been a success, though none of the success came quite as easily as we'd hoped. Just about everything seems to take longer and require more more effort, elbow grease, debugging, and loss of sleep than I expect going into it. Even though I've come to expect incorrect expectations, setting that twiddle factor seems to be one of the hardest but most important skills that one can acquire through experience.

Skiing after Yeti on the endurance test.

The night before last, I had the opportunity to speak to Roberta Palmiotto's class of 9th and 10th graders, who had a number of great questions about Yeti and life in Antarctica. Thanks to Roberta and the whole class, it was quite the treat to talk to them, and hopefully a few of them will consider joining the next generation of polar roboticists. It's clear that there's unbounded potential for robots in extreme environemnts, but one of the constraints on the Yeti project has been getting the right combination of people and skills to design, build, program, debug, test, and deploy the robot. This is definitely the coolest job I can imagine, aside from my work at PSI, which is essentially the same thing but more secret and indoors. One of the major next steps is finding the right people to carry the project forward, though I'll have to leave that to Professor Ray and Jim. They recently received word that their proposal to extend the 'Cool Robot' project was funded, which is really exciting news.

I've been told that Halloween is the biggest and most significant holiday down here at McMurdo, and everyone pulls out all of the stops with creative costumes. I was scheduled to fly out about 4 hours before the Halloween celebrations began, but every single flight in the last two weeks has been delayed, and several people have spent another full week just waiting to take off. Hoping I would get a 12 hour delay and fly the next morning, I eagerly waited and waited until it became clear that the flight was not delayed and I really would have to leave. To add insult to insult, I'm the ONLY passenger on this flight from McMurdo, joining one Medical evacuee from the South Pole. I'm not sure what the cost per hour to operate a C-17 'Globemaster' is, but I'm pretty sure that my return trip cost is in the hundreds of thousands of dollars. I was expecting to be crammed in with pallets of cargo but I'm sitting with the flight crew and an entirely empty plane. I'm guessing that the plane delivered a bunch of cargo on the way in, but it's still quite the experience to get a private flight on a $237 million dollar air force plane (some sources say only $191 million).

One last look at Mt. Erebus, outgassing volcanic steam and vapors on a perfect afternoon.

I got to ride up in the cockpit for a while, and the pilots from the National Air Guard gave me a walkthrough and answered some questions about the plane. I thought that our drive in the Case tractor, at 3 gallons per mile, was pretty poor fuel efficiency, but that's NOTHING compared to this beast. This trip to take me off the ice will burn 180,000 lbs of fuel, or approximately 35,000 gallons. I felt bad about commuting to work in a civic every day, but apparently this one trip alone will release 270 TONS of CO2, putting me at 67.5 times the average worldwide annual CO2 emissions per person for this one flight alone. That sounds unbelievable, but it's based on a burn rate of 7,000 gallons per hour, and 3 pounds of CO2 output for every pound of jet fuel burned (oxygen atoms are heavy...). The plane was bringing food and supplies down to McMurdo, so I'm just catching a ride on the way home, but it definitely doesn't give me warm fuzzies for being a good global citizen. I just found out that there were supposed to be another nine people on this flight, but somehow ALL NINE OTHER PEOPLE convinced the NSF that they had a good reason to stay for Halloween, and I was the only one without a good enough excuse :(

The sadly empty inside of my private C-17.

On Wednesday morning, we had several hours to perform the last test on Yeti. Since everything else worked out well, we wanted to show that we could program an autonomous run in which Yeti would traverse out across the ice to a predetermined point, then execute a rosette pattern over a simulated crevasse location to collect radar data from different approach angles to the crevasse. This should have been trivially simple, but required scaling up the number of waypoints we sent Yeti from 10 to 150. After finally getting everything set up, we sent Yeti out to execute a 1 mile run with two rosette pattern searches along the way. It perfectly executed the first, then stopped and waited for instructions. With 10 minutes remaining before we had to crate Yeti up to ship it back to NH, we had to stop the test and bring it home. I'm pretty sure that this is a trivially simple bug that caused Yeti to stop early. This is a capability we can easily demonstrate back in New Hampshire and an add-on to our original goals, but it was still a little frustrating that it didn't work without modification.

The view out the window on the way home.

I'll continue writing until I get home, on Sunday the 7th. I'll be holed up in a library in New Zealand furiously working away on projects for PSI until then. I need to thank everyone who helped make this trip possible. I'd principally like to thank Jim Lever and Professor Ray for creating this opportunity which began in 2007, and sticking with the project since that time to help in every possible way. Without their advice, guidance, and support, we'd never have made it off the drawing board. Our Greenland deployment, and subsequently this trip, would not have been possible without the sponsorship and support from Ken Corcoran and the folks at Geophysical Survey Systems Incorporated. Thanks also to my 190/290 project teammates who worked insane hours through 2007-2008 to build Yeti in the first place, and Chris, Taro, and Max who did the groundbreaking and exhaustively thorough initial conceptual chassis design. I wonder if they ever expected to see it get this far, I certainly have been pleasantly surprised. Finally, thanks to everyone else at Thayer who helped us along the way. Thanks to all of the support staff at McMurdo and with the USAP. They outnumber the scientists by 10:1 and work 6-days a week, 10 hours a day. Many of them come to Antarctica for the unique experience, but have to earn the right to be here by working insanely hard, many with irregularly rotating night shifts and without weekends. I also need to thank NASA's Jet Propulsion Lab for the initial education grant that funded us to build the robot, and the NSF for their continued support of our field operations in Greenland and Antarctica.

Lastly, but extremely importantly, I'd like to thank everyone at PSI for making it possible for me to take a few weeks off to be here. Initially it looked as though the scheduling would work out a lot better than it did in reality, and I need to thank Brian, Jay, Emily, Charlie, Pete, Peter, Marty, Jim, and especially Dave for picking up some of the slack while I'm gone. Now that I'm back, it'll be a few weeks of the 6-day 28-hour schedule to get caught up and prove my worth again :).

Endurance Testing

2010-10-29T04:04:00.001-04:00

We've been working furiously to finish up the project before our scheduled departure date back to the states. I've got a bit of catching up to do with the blog, since we've been doing a bunch of runs and tests since the weekend. After getting back from the Shear zone, our highest priority was in showing that Yeti could complete a fully autonomous and uninterrupted run without any input from the users. The test in the shear zone was mostly successful in that Yeti operated reliably and completed its fun while collecting the radar data we were looking for, but we had to stop it a few times and I made several mistakes that caused it to stop and restart. We wanted to show that we could complete a course longer than five miles entirely hands off, so I worked to set up a course on the sea ice near to McMurdo.

We have several challenges to staging this test. The first, is that prior to this deployment, we had not had the opportunity to fully test the radio range, and our observed range was MUCH lower than what we were expecting based on the manufacturer's claims. The datasheets said 60 mile range, but that apparently assumes that each antenna is 100' off the ground, which is obviously impractical for us. Instead, we were finding that we could only reliably communicate out to 3/4th of a mile, which is basically worthless when we're operating 5 miles away.

I set up a few tests and was able to get reliable communication at 3 or 4 miles by raising one antenna a lot higher off the ground and sending very short messages. We only had one day to perform the final endurance trial for Yeti, so everything was coming down to the wire. I wanted to make sure that we wouldn't lose radio comms under any circumstances, so I had to MacGyver together a tall transmitter and pole. The final design used the following parts:

9 bamboo poles
1 roll of duct tape
1 sharpie
2 hoseclamps
2 chemical handwarmer packets to keep the batteries warm
1 chemical spill blanket to insulate the batteries
1 piece of rope from the crevasse rescue bag
4 serial cables, one of them homemade

My kludged antenna mounted on the living module.

The final antenna pole was somewhere between 25'-30' tall when mounted on the living module for the traverse. The rest of the traverse team was laughing at this epic kludge, but it turned out to be brutally effective and gave us a significant improvement in range.

The other major constraint was that we didn't have access to a truck since another 50 scientists have shown up and resources are pretty tight. They've started packing 3,4, and even 5 people to a single room in some of the dorms, but luckily Jim and I have escaped that mess by virtue of the fact that we're leaving in a few days. Not having a truck to chase Yeti makes everything a bit harder, since we wouldn't have any ability to stop or fix it if there were any problems on the run. We were confident enough that it would perform well that we weren't too worried about it, but I still wanted to be there in case something happened. The only way I was going to be able to keep up with Yeti was on skis, so I got a pair of skate skis and took them down to the traverse staging area.

I haven't cross country skied in over seven years, and haven't ever tried skate skiing before, so this was going to be a bit of an interesting challenge. Ben Koons, a friend from Dartmouth, skied for New Zealand in the Olympics, so I assumed it wasn't too hard if he had gone that far with it (Hi Ben). I tried double-polling for about 100' and it seemed pretty easy, so we set Yeti up and sent it the waypoints. I called to Jim on the radio to press the play button and we were off.

The first several hundred meters were a breeze, and I had no problem keeping up with Yeti despite my total lack of any skill on nordic skis. After about 500m, I started slowing down appreciably, and noticed that Yeti was starting to get out ahead of me a bit. The full course length was 6.7 miles, so I began to get a little nervous. It got A LOT worse over the next couple miles, and Yeti proved to be a totally unrelenting pace car. Somewhere around mile 2.5 I started to get the hang of skate skiing, at least to the point where I could pour on the heat and sprint ahead of Yeti, then take about five seconds to recover and start slogging along again.

I made a mistake while getting the coordinates and hadn't fully appreciated the slight bend in the road to Pegasus. This meant that Yeti had to cross through a line of bamboo flags twice both out and back along the route, and I was worried that it would get stuck on one. The first time it crossed the line, I was heaving to keep up with it and couldn't get to it in time as it was heading straight for a flag. Yeti managed to snap it in half without any problem, and continue on, perfectly threading its way back across the line and narrowly avoiding another flag on the way back. We might need to install some vision systems in future designs, but for now it seems to work to give Yeti enough power to mow over whatever lies in its path.

Right around mile 2.3, it made a turn towards a waypoint and looked like it was heading home, which gave me a huge sense of relief, but then continued on its way and I realized I was only a third of the way into the course. After what seemed like an eternity, we reached the turnaround and Yeti successfully hit all of the waypoints and started back home. This time I was more determined to make sure Yeti didn't hit anything, so I tried as hard as I could to stay out in front. It managed to avoid everything else along the way, and make it back home.

I was totally wiped out and Jim was laughing at me when we got back, but the test was a total success and the first time that Yeti had finished a long distance course without any input or restarts.

I'm a little too addicted to the soft-serve ice cream here and eat it even outside. I had an interesting experience yesterday where for about half a second I was wondering what was going on when I realized that my ice cream was getting harder and unmelting after I walked outside into the -20 degree air. It kept getting more solid until it became difficult to eat, which was definitely the first time that had ever happened to me!

The sun partially occluded by Observation Hill on the way home from Scott Base to McMurdo.

Out at the Shear Zone

2010-10-25T08:58:00.001-04:00

Sorry for the long delay! We just got back from the shear zone, about 30 miles out from McMurdo. Seeing it for the first time really helped put in perspective what we've been working on for the last couple of years. The shear zone is the area where the Ross ice shelf meets the McMurdo ice shelf. The two shelves have different speeds, creating a particularly nasty area riddled with crevasses at the interface between the two. The traverse route crosses perpendicular to the shear zone, but still has to travel over 3.5 miles of heavily crevassed terrain. These cracks change season to season, and often times new ones open up each year. All of them are invisible from the surface, however, and many are hundreds of feet deep.

Jim and I drove a Case tractor to get to the South Pole Traverse camp on the near side of the shear zone. I found out while en route that our vehicle has an excellent fuel efficiency and burns 3 gallons of diesel per mile travelled. The route was covered in dense fog, which made it hard to see the flags marking the ice road. In those conditions out on the sea ice, it's a strangely surreal feeling to be surrounded by absolutely nothing but white, with no visible horizon or visible features of any kind. Luckily, we were able to navigate by GPS between flags, and reached the traverse camp on time.

Our Case, loaded up with Yeti and equipment in tow.

The SPoT camp, with living module (red) on the left, the H2 module (my living space) in blue, and several tractors.

We were initially supposed to have a week to test Yeti in the shear zone, but that got crunched down into 2.5 days. The first day, our goal was to collect radar data over a crevasse and setup the route that we would send it off on for an autonomous run the next day. Zoe and Allan headed out ahead of us in a Cat, and Jim and I followed in a tractor. We were looking for one specific crevasse that would give clean radar signatures so we could collect a data set that will later be used to autonomously detect crevasses. When Allan drove over the snow bridge in the cat, it opened up a small hole on the surface. Jim and I saw the hole just as we were about to drive over it, and weren't able to stop in time. We knew the crevasse was only a meter or two wide, but it was bizarre to look behind us and see the hold widened out to around 5 feet. We had to backup and drive back over the hole again, since the road was the only portion of the ice that had already been surveyed. The Case made an ominous sound clunking in and out of the hole, but we made it back across in one piece.

After successfully 'finding' a decent crevasse to survey with Yeti, we attempted to drive a rosette pattern to approach the crevasse from different angles with the robot. Our only goals were to keep Yeti driving straight and avoid the 5' hole we just made, and I found it absurdly difficult to keep Yeti safely away from the hole. At the time, I decided that this was target fixation, but we would soon find that Yeti has a magnetic affinity to holes in the ice and bamboo flag poles. While driving around autonomously, it seems to lock in with laser precision on the only one or two obstacles around for miles, which I'm sure is a corollary of Murphy's law.

It's almost 2am and I have to get up early for another long day of testing, but I'll write up the rest of the work at the shear zone tomorrow. Rest assured that Yeti did not fall in a hole, but did annihilate many bamboo poles.

Mt. Erebus, an active volcano, from a distance. It's not really nighttime, since the sun stopped setting last week, but it does go low and create very cool lighting conditions.

Running on Ice

2010-10-20T07:04:00.001-04:00

A lot has happened here at McMurdo since my last post. Our deployment date to the shear zone keeps slipping back, so we're doing more work to test and prepare Yeti on the ice around the station. Two days ago, Jim and I took Yeti out to the SPoTSA (South Pole Traverse Staging Area), and set up our first endurance course to run Yeti for several miles. It had already performed just find on several shorter courses closer to home, so we were both expecting this to be a bit of a formality. We set everything up and pressed play, and Yeti drove off into the sunset towards the outbound waypoint. After about 1km, it hit the next two waypoints and turned to head home, but then kept turning in a 50m circle, and kept going around and around. This was pretty bizarre, but radio comms had been dropping out, so we set it up again and chased it with a truck to stay in radio range. The exact same thing happened again, and left us head scratching.

Yeti outbound on the endurance tests with Mt. Discovery in the background.

We headed back in and I downloaded the telemetry data. It became clear that a bug in the error handling for the GPS input had caused the problem, and the GPS had dropped out at exactly the same point in both runs. There appears to be an intermittent power connection to the GPS which causes some brief dropouts, and the program caused the robot to hold its last command, which in this case was to turn slightly to the right, making it drive in large circles indefinitely.

I rewired the power distribution and tightened down all of the connections, and added a much more robust error handling routine to the code in a late-night push to get everything fixed and set up for another day of testing. I managed to have a bit of a nailbiter of a night, however, when I was tested the intermittent power failures and managed to flip Yeti over, snapping the GPS antenna off. Luckily, everything other than the pole holding the antenna up was fine, and the machine shop at vehicle maintenance was able to build a MUCH nicer antenna mount in a few hours. I then spent yesterday re-running endurance tests, and everything worked out extremely well, setting us up for our first runs with the radar units.

I saw a 'Sun Dog,' while performing endurance tests. These are like rainbows but formed due to small snow crystals in the air, and are all white.

There are several interesting applications apart from crevasse detection that we're going to test Yeti out on. We're going to try looking at sea ice to determine thickness and quality to see if it's feasible to use the robot to survey the airfields here. Apparently they have to drill 30 boreholes a day to profile the ice conditions, and we could dramatically improve the efficiency of that process with Yeti if the radar has a high enough resolution. Allan Delaney will be helping us with the radar to test this and see if it works, which could potentially open up another source for grant funding if successful!

A C-17 on the ice runway, viewed from SPoTSA

Final Preparations

2010-10-15T10:02:00.001-04:00

After making Yeti work pretty well, all of a sudden there are a bunch of other things to do. Jim has developed a datalogger system for the large fuel bladder sleds that will record a temperature profile from the bottom of the sled using 46 thermocouples and a huge mess of wires. We spent the day out at the traverse staging area installing the thermocouples while the rest of the team sorted food into the refrigerator container sled. I would have thought that since we're in Antarctica and it never gets above freezing that the traverse would not need a dedicated walk-in freezer the size of a whole living module, but apparently the sun heats everything up enough that they do. Instead of circulating the sub-zero air from outside, it operates as a standard freezer, which is a little absurd but comes pre-built, and thus makes sense...sort of.

This is the living module that will house eight crew members. The insides are actually very nice with ample space and a comfortable kitchen and lounge. There's not a ton of privacy, but significantly more space than a naval ship.

Jim and I, if we're lucky, will be living in the H2 module. This guy has two bunks at the top, and living space below. It's sort of like sharing a tall cubicle with someone for a week, though remarkably comfortable and well designed.

While we were out in the staging area, I had an excellent view of Mt. Erebus outgassing behind McMurdo. Erebus is an active volcano, and has active fumoroles and lava pits on top, but I haven't been able to see the smoke before today. Apparently this is one place where a lot of volcanologists with no direct interest in Antarctica come to do research, since it's one of the few volcanoes in the world that's continuously active.

On the way back from the traverse staging area, I was lucky enough to catch a team of French scientists launching a high-altitude research balloon. The launch operations are very involved and elaborate. I unfortunately have no clue what they're actually doing, but I'll try to find this out.

We met another group a few days ago doing interesting robotics work out of McMurdo. This group has developed a robot named SCINI (skinny), which is an underwater ROV designed to fit down an 8" drilled hole in the ice. It's operated on the end of a tether, and has a number of cameras and a gripper. They're using it to look at the results of 40-year growth experiments that have been sitting on the bottom of the ocean floor since the 70's.

These guys had to deal with an additional operational issue that we have yet to deal with on the Yeti project. They're operating in a small shack over a drilled hole in the ice from which they pilot the ROV. A local seal has decided that it likes them, and will frequently come up the hole in the ice and into the shack to hang out. It signals that it wants to play with them by blowing bubbles in the water, and blowing air and water at them. They thought this was awesome the first time, but after encountering this fellow many times, his habit of sneezing mucus all over them is apparently not as funny as it used to be. Bob described it as 'lung butter,' which sounded like something that shouldn't get sprayed on computers.

The SCINI robot is really cleverly designed to fit down small holes in the ice an carry a number of different payloads to support different science missions.

The team let us try driving it around. They control SCINI with a wireless playstation controller which is a lot slicker than Yeti's 'toolstation.'

We had some more successful runs of Yeti down by the ice pier, and seem to be holding sub-meter tolerances to GPS waypoints. The controller could use some tweaking and some integral control. At the moment, when Yeti hits a waypoint, it turns towards the next one but makes a sweeping arc to get there. Since we need forward motion to estimate bearing using successive GPS points (we can't use a magnetometer since magnetic bearing doesn't work near the poles), I don't have a closed-loop way of reorienting Yeti towards the next waypoint. The result is that we can hit all the waypoints but don't hold a tight path between them. I'm working on a quick hack of a solution to have Yeti spin at a given rate for a given period of time, which will probably get us most of the way there and isn't really rocket science.

Autonomous at Last

2010-10-13T08:02:00.004-04:00

Great news! Jim and I fired up Yeti with the first version of the new autonomous control code and it works astounding well even before tuning the controller. For those of you who are interested in the details, read below, otherwise skip over the next paragraph. We're heading out to the shear zone on Saturday now, and Yeti looks to be in great shape to complete the mission, though it took a string of anxious nights of hanging out alone in three layers of jackets hauling Yeti up and down stairs by myself at 2am to get here. I seem to have overshot the required effort level a bit since we still have a couple days, I guess I'm getting out of practice on the 'procrastinate and cram' cycle.

Yeti before the trial run, looking out over the ice runways towards the Transantarctic mountains:

The niche of a subbasement where all of my work gets done. One pro of this arrangement is that I get to try out the new concept of working at a standing desk. A con, however, is that the desk happens to be a barrel of toxic waste, and covered in the dust of some other toxic waste*.

After several days of pouring through the details of the code and implementing a bunch of features I've always wanted but never had time to develop, I finally put a few pieces of test code together into the first version of the autonomous control code for Yeti. I've been 'almost there' for several days now, and it was seemingly frustratingly slow to get all of the issues hammered out. When I finally put all of the new code together, I called Jim to come help me get Yeti outside and to be in place to tackle it in the highly likely event that the first version of the code didn't work and it decided to go on the fritz. One of the key issues roboticists have to deal with is preparing for the inevitable eventual human enslavement to robots. It helps to have someone close to the off switch to preempt any precursors.

I surveyed a few waypoints out near the ice pier at McMurdo, and drove Yeti out there to start the testing run. I assured Jim that there was no way it would work, and nervously pressed the button to begin the run. Yeti took off and made course corrections towards the first waypoint, found the waypoint, then reoriented and finished the route. I was surprised enough that I had to try it again, and in ran the route in exactly the tracks it had just made. We then took it out for a longer and more complicated run, and it executed that route flawlessly. This is great news, because now we can focus on improving the reliability and making the robot more generally useful, in addition to adding all sorts of unnecessarily sweet features.

If you're not interested in why the new version works and the old one didn't, then skip this section. After spending a lot of time drilling into the code, I found that there was an issue in translating lat/lon coordinates to cartesian coordinates in which the least significant digits were being truncated and rounded, artificially limiting precision and creating an unnecessarily low resolution for a bearing calculation. I found that if I did all of this arithmetic on only the decimal lat/lon minutes, you get much better performance. The key breakthrough that made it possible to test and isolate the problems were twofold. First, I began to use the powerful debugging features built into the Dynamic C development environment, and second, I implemented a more functional telemetry that allows Yeti to transmit data back to the basestation for processing and analysis. Before this, we had to test code by driving Yeti around and seeing if it was roughly doing what we wanted it to do. The previous version of the code accomplished exactly that - it roughly accomplished what we were trying to do. Now, however, I can finally throw Matlab at it and have some confidence that we've got it right. I'll post some plots tomorrow after another round of testing.

Some more pictures:

This is a memorial erected to Scott in 1912 on top of Observation Hill next to McMurdo on the very end of the peninsula on Ross Island.

Toby, one of the mechanics, built this snow chopper entirely out of salvaged parts from junker snow machines, and it works just fine. Note the ice axe built into the front suspension.

This is one of the Case tractors that will be hauling fuel on the traverse. These machines run around $500,000 stock, with an additional winterizing fee. In 2008, the Greenland traverse got one of these stuck in the ice 50 miles outside of Thule and had to leave it there. They came back a year later to find it entirely buried in the ice, and sent a team of people to recover it. It took them several weeks of digging to free it from the ice, and eventually they got it out.

These never get old, every night is different.

I'll have a more time tomorrow to post pictures (I know that's all that most people see :) and some pretty plots of telemetry data. I've also received some extremely well considered and length responses to the 'should you pee if you're cold' argument and will post links to the solutions that some people have posed. If anyone else wants to throw their hat in the ring, send me your response. I've recruited a coalition now on base that's on the thermodynamically accurate side of the debate, but many remain unconvinced!

*These barrels are probably not filled with anything that is either toxic or waste, since neither are allowed under the Antarctic treaty. Technically I'm not even allowed to pee outside the building, and any drop of fuel or even food that is spilled gets cleaned up and packed out.

Long Hours and Debugging

2010-10-12T08:50:00.000-04:00

The new schedule has proved to be challenging but effective for getting a lot done with Yeti. Yesterday I went to bed at 5am and was supposed to sleep until 2pm, but found that I keep waking up far earlier and end up getting far too little sleep. Despite this, I've had some solid long blocks of time to debug issues with Yeti.

I've been working through a lot of reliability and performance issues that we've seen all along. When we first built the robot, the code and electronics were all developed somewhat ad-hoc, somewhat against the advice of Professor Ray. We've found numerous small reliability issues that are each small, but when compounded, mean that whoever is operating the robot really needs to understand everything that's going on internally. The goal of being here this year is to make a compelling enough case to propose additional funding to develop a more reliable and field-hardened system.

One of the most challenging aspects of developing the code on Yeti is that I actually have to run it around outside in order to test the GPS navigation. When things aren't working, it can be really challenging to figure out exactly why they're not, and the time to iteratively test and debugging code in little pieces is much much higher than when you're writing code to execute on your own computer. I spent the last day building telemetry into the code, so I can get data back over the radio and not have to chase around the robot while holding a laptop that's plugged into it in -20 degree temperatures and high wind. We're really close at this point, and I've made huge improvements in the numerical stability of our navigation code, which I'm hoping to test tomorrow after crevasse rescue training.

During our happy camper survival training, I quickly became annoying in holding down one side of a debate that's always bothered me. If anyone can point out something I'm missing, let me know. The debate was whether if you're cold, you should pee, because your body is expending energy to keep the urine warm. I argued that this is totally wrong, and that it makes sense to pee because it's uncomfortable, but that you don't lose any more heat. Three PhDs in various fields of science, along with a recent graduate who had 'just taken thermo' all argued the other side. The basis of my argument is that all of your heat loss is through your skin via convection, conduction, radiation, and some evaporation, and all of those remain constant before and after urinating (ignoring the negligible change in skin surface area accompanying the smaller volume of your body after peeing). Similarly, since the urine is already at body temperature, you don't need to do any work to change its temperature. If you work out the energy balance, the metabolic work going into maintaining body temperature would equal the m*c*delta T of the urine minus the heat lost on your skin. Since delta T is zero, you're not doing any work to keep it warm. The counter point, as far as I could tell, was simply that "with more mass, your body needs to expend more energy to keep it warm." In reality, the other side didn't really care that much, but it's just so hard to let someone be wrong! Following that line of thought, feel free to correct me: etrautmann@gmail.com

We're heading out to the shear zone on Friday and I likely will be off the grid for a while then. I'll try to post updates when I can.

Almost There

2010-10-10T08:54:00.002-04:00

I'm beginning an exciting new schedule that I've been waiting to try for some time. This week I'm implementing a six-day week of 28 hour days, going asynchronous with the rest of the world and living on my own clock. The rationale for this is that it allows you to work in long blocks of time and increase efficiency, and actually synchs up reasonably well with the times of the week that are important. I've joked about trying it for a while, but now's the only opportunity that I've had where I'm working entirely on my own and set my own schedule, and it never gets dark. We did a pretty good job of doing this accidentally while working 18 hour days in Greenland, but I'll be trying to stick to this schedule more rigorously. See this XKCD for reference:

After getting back from Happy Camper training on Saturday, we had an all hands on deck meeting in the McMurdo Galley because the whole station is facing a housing crisis. Apparently there are 150 extra people that will be coming at the height of the season, and this means turning some double rooms into quintuples. We're not affected by this since we're considered 'Beakers,' and have our own building. A number of people, however, have made this their permanent home, and have lived in one room for eight or more years and don't have a home in the US. Now, some of those people are being given roommates, and there's a significant amount of drama beginning to unfold.

On Saturday night, I went to my first party at one of the shops here, and was surprised to find about 100 people, lights, and multiple bands on stage. The ratio of support staff to scientists is something like 10:1, with about 1000 people here as mechanics, dining hall workers, carpenters, and pilots among others. Many of the twentysomethings I've met here describe it as a summer camp for adults, though I've been working bizarre hours and haven't to spend much time socializing. It's also been described as a caste system with the scientists on top, and being a grantee gives you a surprising amount of clout. I exist somewhere in between since the South Pole Traverse is considered a Technical Event, but I feel pretty lucky to be down here and working with robots. There are a surprisingly large number of DAs (dining assistants) and carpenters with an M.S., and I met a girl last night who just came back from a Fulbright scholarship working on public health in India and will be spending the whole summer season shoveling snow off of pipes but is incredibly excited just to get to be here.

I've only got one good photo in this batch, the sunsets here are consistently blowing me away. This one is looking out over the Helo pads towards the Transantarctic Mountains.

I've debugged most of the robot code and fixed an issue with the GPS today, and built a set of debugging tools that will help streamline the process of debugging Yeti in the field. We're all set up for our first autonomous run tomorrow morning, so I'm crossing my fingers that all goes well. We're planning to deploy to the shear zone to begin mapping crevasses on Friday, so we still have a few days to work out issues and make improvements to the code (and there are many to make). The orientations are endless, and I'll hopefully be fitting in the testing around the eighth or ninth orientation, this one about environmental sensitivity. I've already had three on safety, one on base protocol, two on recreation policies, one on driving, two days of survival training, and one on sorting trash. Later this week I'll cap all of the sessions off with crevasse rescue training out on the ice which actually stands a chance of being fun and interesting.

Happy Camper Survival Training

2010-10-09T04:23:00.000-04:00

I just got back from the 'Happy Camper' ice survival training course where we spent two days out on the ice learning the tricks to surviving in style. I made a rough calorie estimate for yesterday and I'm ballparking anywhere between 6000-7500 calories consumed during the day.

The course started with the 20 of us 'happy campers' in a classroom, reviewing the finer points of risk assessment and McMurdo emergency protocols. After that, we loaded up our (Extreme Cold Weather gear)++ and headed to the Delta, an absurd looking vehicle designed with absurdly large and low pressure tires for driving people over snow. They gave everyone five minutes to gather extra equipment that they might have forgotten, and everyone thought it was hilarious that I came back with an ice cream cone from the 'frosty boy' dispenser. I'm up to five or six ice cream cones a day, there must be something addictive that they add to the sugary slop that goes into the soft-serve. I've even gone so far as prepping for a hike up observation hill in -10 degree temperatures by bringing along some ice cream.

Heading out to the ice on the Delta

Everyone loaded into the Delta with ECW gear on.

We drove for about 30 minutes away from McMurdo, through the Scott base (the New Zealand Antarctic Base), and arrived at our field camp, a Jamesway shelter set up on the sea ice. In the shelter, they brought out the first of what would be several absurdly large meals. They fed us sandwiches that easily had a full pound of turkey, or about two full inches of meat, along with bacon and cheese. On top of that, we had liberal amounts of fig newtons, chips, cookies, M&Ms, ritz, and plenty of chocolate. After some basic training on how to use camp stoves, we headed back out to the ice to set up camp for the night.

We hiked about half a mile and picked up gear, including some huge tents, and lots of shovels and wood saws to build up camp. I'd been through most of this training before, so what I was really looking forward to was building things out of snow. I got really excited when it came time to start quarrying snow blocks and building wind walls. We set up a professional quarrying operation, using rope as a snap line to mark out cutting lines in the snow, and had a number of people shuttling overfilled sleds full of 80 lb snow blocks between the quarry and camp. Everyone else was satisfied by building a basic wind protection wall, but Kris and I spent another few hours building a coliseum eating area complete with benches and tables.

Our instructor Bryan showing us the finer points of sawing snow into blocks.

We're about one week away from the point at which the sun no longer goes down. Right now, since the sun approaches the horizon at such a low angle, we're treated to HOURS of the most beautiful sunset I've ever seen.

The sunset with the wind turbines that power Scott base and a portion of McMurdo. These were installed last year, and I believe more are scheduled for installation soon. All of the other power is supplied by diesel generator, which is why McMurdo has so many ugly 2M gallon diesel tanks (see below).

All of my construction came at the expense of spending time building a survival trench in which to spend the night. Many of the other members of the group were working on building themselves small snow caves instead of spending the night in a tent. Somewhere around 11:30, I decided that it would be fun to spend the night out, and decided to sleep in the non shelter that I'd been building. Our sleep kits included two sleeping pads, a ridiculously lofty sleeping bag, and a fleece bag liner. There wasn't any wind or snow, so the conditions were perfect for sleeping out. It took a while to get perfectly situated, but it was really warm and comfortable when I finally went to sleep. I woke up sometime in the early hours and the wind had started blowing from the exact opposite direction we were expecting, and directly through the only opening in the circular structure I was using as shelter. Despite this with something like eight layers on, I was still pretty warm and able to get some sleep. I found out later in the morning that the temperature had gone down to -21F.

In the morning, we packed up camp and headed back to the shelter to run some practice emergency scenarios. In the first, we had to wear 'whiteout buckets' over our heads to simulate trying to execute a missing person search in whiteout conditions. All we had to do was to get from the shelter to the latrine 100' away to find someone, and the route was marked every 10' with bamboo flags. Stephen and I headed out on the end of a rope, and thought were were doing an excellent job of routefinding towards the latrine. The instructors stopped us after about four minutes, and when we pulled the buckets off of our heads, we were on the wrong side of the shelter moving in the opposite direction after accidentally pulling a 180 and following the wrong line of flags. It was extremely disorienting and a bizarre shock to my senses to pull off the bucket and be so far from where I thought we were.

After that, we had some ham radio training using old korean war hardware, and ran a medical emergency scenario. This was a great reminder that my medical skills have fallen off significantly after not ski patrolling for several years.

Radio training inside the Jamesway shelter.

Tomorrow I'll get back to Yeti. We're working on diagnosing some bizarre behavior in the code and I've been slamming my head against a wall and hoping for a breakthrough soon. It's certainly not dire and we have a number of days to make everything work, but I'd really like to get everything working perfectly so we can get some real science done with the radar.

The whole album of photos is up on Picasaweb here:

Antarctica 2010 - Yeti Robot

Yeti's First Steps

2010-10-06T06:48:00.003-04:00

Today was a big day. After meeting the traverse team in the morning, Jim and I headed over for my fifth orientation briefing. This one was an in-depth hour long presentation on how to drive a pickup truck, which basically boiled down to simple point that you need to unplug it before you start driving, since the trucks have electric heaters to keep the oil from freezing at -40.

After the briefing, we headed over to our workspace in the 'Incinerator Building,' which is actually a lot nicer than it sounds. Aside from the fact that I'm working next to open barrels of gasoline keeps a pungent aroma of volatile organics wafting through the air to keep me pleasantly sedated as I work, the shop space is quite nice.

After unpacking our five crates of gear and equipment, we took Yeti out for a spin. After crossing our fingers and hoping for the best, it was excellent to see that Yeti was working out of the box, at least in manual control mode. I'll need to make some updates to the code to enable Yeti to drive autonomously down here. In a classic case of hilariously bad coding, we wrote our initial code to interpret very specific messages from the GPS. Since all of the development was done in the Northeast, we never had to deal with the extra character that comes from being at 166 degrees longitude. Changing that isn't hard, but testing the code is surprisingly challenging, since it involves loading Yeti up into a pickup truck and driving it out onto the ice. Iteratively testing code is pretty tricky since the turnaround time is on the order of an hour or more.

Yeti out for the inaugural drive with McMurdo and Observation Hill in the background.

My next post will be all about what I'm assuming most people actually care about - the people and life at McMurdo. Let me know if you're curious about anything else!

McMurdo at Last

2010-10-05T05:56:00.004-04:00

A lot has happened in the last couple days. I apologize for the lack of posts lately, I'll be writing daily from here on out, usually posting around 3am eastern time.

After a weather delay which kept us in Christchurch for an extra day, we shipped out at 5am this morning to board the C-17 for our ice flight. I narrowly made my shuttle after bolting out of bed late, worried that I might not make it on the flight. We arrived at the US Antarctic Program headquarters to suit up in Extreme Cold Weather gear and do our final packing, which was a little more complicated than a normal flight. You get a small carryon, a large checked bag, and a 'boomerang bag.' In the event of stormy weather which would prevent the plane from landing at McMurdo, the boomerang bag is the only bag that will be returned to us when we land in New Zealand, so that has to contain nothing that we want on the flight, but everything we would need if we had to stay another few days in Christchurch.

After suiting up in our gear, we had a 'hurry up and wait' situation before another video briefing (number 2), then passing through customs and security. I was surprised to see that we have to go through the equivalent of pre-9/11 airport security. We then bussed out to the tarmac and boarded the C-17 in a single-file line of 70 ridiculously overdressed and sweaty people wearing bright red ECW jackets.

Our flight attendants were all air force 'loadmasters' who were in charge of stacking us in between cargo pallets and bags. I was told that the total lift capacity of the plane is around 170,000 lbs, which is enough to lift the largest tanks the US uses. I don't have much more time on internet so I'll let pictures speak instead.

Looking over the Mountains about an hour outside of McMurdo

Gracie has been kind enough to show me around and not treat me like a total fungi (FU***** New Guy on the Ice).

One of the great things about this trip is meeting all sorts of interesting people. This is 'Diesel' showing off her sporty calculator watch from 1995.

Unloading on the ice sheet downhill of McMurdo.

Immediately after unloading the plane, I got onto a bus and took this photo. The girl in the photo looked at me and said "Eric Trautmann? Didn't you go to Ithaca High School?" Turns out Anna and I sat next to each other in 9th grad social studies class. This is the third extremely small world experience I've had so far on this trip, at this point I'm just expecting it.

These are my accommodations for the next week before we head out to the shear zone on the ice.

McMurdo isn't the most beautiful town in the world, but the surrounding scenery is breathtaking. More photos to come.

Christchurch

2010-10-02T03:19:00.003-04:00

I touched down yesterday and feel like I stepped straight into the '90s. While New Zealand is technically considered a developed country, it seems to take between 6 months and 15 years for new concepts, trends, and technologies to reach the country :) I wrote this yesterday, but my internet 'ran out' so now's the first time I could upload it.

Here's my post from Yesterday:

As a disclaimer, this post is devoid of any technically interesting content since I'm 'trapped' in New Zealand for two days without the robot or any of my colleagues. I've been forced to endure the harsh realities of attempting to fill downtime as an adventurer in New Zealand (while writing some Matlab code on the side to keep things fun). I arrived in Christchurch today after a seemingly unending series of flights, and my body has no idea what time it is, but I generally feel good to go. In the last eight weeks, I can count the number of times I've gotten more than five hours of sleep with three fingers, so the plane ride was a nice chance to catch up on sleep and watch some bad movies.

I met a series of incredibly cool people along the way, however, which reaffirmed the positive side of my love-hate relationship with long haul travel. I met a woman who works on the Patagonia's catalogs, who may help me try to make it into a catalog. I also met a another researcher named Sally Walker who is a professor studying fossilized single-cellular organisms in the dry valleys of Antarctica. She absolutely obliterated me in the competition for how much gear we each brought. Her checked baggage totaled somewhere close to 350 pounds and included a full sized imaging microscope. The majority of my cargo weight is in books, computers, and my toolbox, all of which I managed to fit into a large backpack. I figured the contents of the backpack were actually fairly sketchy if one were to inspect the bags, as they included an assortment of random electronics parts, hand tools, and books about ballistic missiles and tracking systems, which are obviously unrelated to my work here in Antarctica.

Sally and I met at the baggage claim, and followed a trail of painted penguin tracks to the US Antarctic Program building adjoining the airport. We dropped the majority of our gear and I got to wander around the voluminous warehouse that is the clothing distribution center (CDC). The inside of the warehouse is crammed full of racks and stacks of ruthlessly organized gear, with a team of people running around organizing kits of extreme cold weather (ECW) gear for those of us who'll deploy on Monday. The gear is highly utilitarian, however, so I'm going to look for some comfy merino wool baselayers when I get into town.

Racks of jackets at the Clothing Distribution Center

Each of us will receive one of these kits of ECW gear.

All of these boxes contain nothing but long underwear.

I won't be issued gear until Sunday, when we receive a full briefing and meet the other people on our ice flight, so I'll wait until then to go into more detail. It appears, however, that everyone is issued a standard set of aggressive colored gear, most notably, a bright red puffy jacket designed to be visible from 30 miles away on the ice.

After dropping our gear, Sally and I took a shuttle into Christchurch and checked into our hotels. A 7.1 magnitude earthquake struck Christchurch about three weeks ago, and I was unsure what level of damage we'd see downtown. The earthquake was on the same order as that in Haiti, but it appears that the building codes here were strict enough that most of the damage is minor. Walking around downtown, it's clear that there was some damage to the facades and masonry of some buildings, but it mostly appears to be superficial damage. I'd characterize it as a large amount of relatively minor damage, with maybe 20% of buildings having some sort of scaffolding around them, making Christchurch resemble any city in China. Apparently zero people died in the quake, which is astounding given the magnitude of the quake and the number of people living close to the epicenter.

This is about the worst of the damage that I saw. Most of the other buildings have a few cracks in the masonry but not much else. I've hear that there is far worse damage elsewhere in the city, but haven't seen it myself.

I spent the afternoon walking around downtown, and ended up around dinnertime at a bar/restaurant Dux de Lux, which was recommended to me by every single person I talked to prior to this trip. Within thirty seconds of sitting down, I thought I recognized the girl sitting at the table next to me. It turns out I had climbed with her a couple of times at the Metrorock gym in Boston a little over a year ago. The climbing community never ceases to amaze me by how small it feels. Three days ago, I found out that I'm on the same ice flight as a girl named Gracie, who I met on a climbing trip last September in Oregon.

I ended up hanging out with Katie and five of her friends for the evening, and making plans to head to Flock hill, a beautiful bouldering area in the mountains outside of the city. I've got one more day to go here in Christchurch then I gear up and ship out on Sunday evening and Monday morning. I'm currently 7 hours behind east coast time and it's time for my body to catch up with sleep.

E

We're going to Antarctica!

2010-09-25T16:53:00.003-04:00

The long wait is over! We're dusting off the blog again several days before our deployment to the Antarctic ice sheet with the Yeti robot. I fly down on Wednesday in a long series of flights (Boston-> LA -> Auckland -> Christchurch -> Mcmurdo). I'll be posting here as regularly as possible, though it's likely that we'll be off the internets for a week while Jim and I are out on the ice. I've been told it'll be -40 for a good portion of the time, so I'll be updating this as much as I can in between times when my fingers are frozen solid.

For those of you who are new to the yeti robot project, in 2008, six undergraduate students from the Dartmouth Thayer School of Engineering designed and built the yeti robot, an autonomous ground vehicle designed to perform Ground Penetrating Radar (GPR) surveys of Arctic and Antarctic ice. Later that year, two of us took the robot out for its first trial by fire in Thule, Greenland. That experience was enough to convince me to stick around and do my M.S. at Thayer working on machine learning and improving the yeti robot's mobility in rough terrain. Now we have the opportunity to use Yeti to help the Antarctic Traverse team, and are deploying for the month of October to McMurdo.

The Yeti robot in Thule, Greenland.

The need for the Yeti robot crew out of a recently increase in scientific research in Greenland and at the South Pole, which has greatly increased the amount of food, fuel, and supplies that need to be delivered to these remote research bases. These were usually flown in using C-130 transport aircraft outfitted with skis, but this is both extremely expensive and environmentally unfriendly, and has the potential to impact the science efforts at the south pole by degrading air quality around the optical telescopes. Starting a few years ago, the Polar Programs office decided to reduce costs and impact by bringing the food and supplies overland using large tracked vehicles called snowcats.

The route between McMurdo and the South Pole is a little over 1600km long, most of which is boringly flat snow and ice. Certain areas, however, have large subsurface crevasses that are entirely invisible from the surface. These crevasses can be 1-10 meters wide and hundreds of meters deep, and only covered by several feet of snow and ice. Driving snowcats through these types of conditions can be extremely dangerous unless you know where the crevasses are. The traverse team currently uses a 30' boom on the front of the lead snowcat with a GPR antenna mounted on the front. This gives the driver a 2-second warning before the snowcat hits the crevasse.

The Antarctic Traverse team found this crevasse several years ago and blew it open with dynamite to get a better view.

A Pisten Bully snowcat outfitted with a radar boom on the front. This year, the Yeti robot will be used to supplement these, but hopefully will replace them in the future.

The Yeti robot was designed to address this (admittedly very specific) need for a better crevasse mapping capability. The goal of our current deployment is to collect the first ever autonomous GPR record in Antarctica and show that performing the surveys autonomously can improve speed and safety.

Thanks to everyone who've helped us get this far, especially Jim and the folks at CRREL and professor Laura Ray from Dartmouth for letting us borrow Yeti from her lab. Thanks also to my group members at PSI for helping me to work remotely for a month (It'll be a busy one!). More recently, thanks to the folks at Sparkfun for hooking us up with a GPS and some other components at the 11th hour!

Stay tuned for pictures, videos, and updates. I've been told that we're definitely not allowed to bring home a penguin, as this is protected by draconian international laws with harsh penalties and jail time.

I hope this will be a two-way communication, please feel free to ask lots of questions!

Up to Summit

2008-05-13T22:48:00.005-04:00

After threats of a 6:30 am flight, we relaxed a little bit when we got word that the Hercules would arrive around 10:30. The whole team headed out to the transition to test the tow rig for the fuel bladders they're hauling on the traverse. Apparently the skis supporting the tow rig had some issues that would take a day or two to resolve. At that point, we heard that our plane could be delayed for a day or maybe two, who really knows? Kevin and I tried to fight our drive to escape the toast and mashed potatoes that have been sustaining us here, and headed back to while away the hours on the interweb and take a crack at final cut pro for video editing.

After a couple hours, we heard news that the C-130 was indeed on its way and would land in several minutes. We ran to grab the last of our gear from our hangar space. As we saw Yeti for the last time, Kevin and I chose the good cop/bad cop approach to behavior shaping. Yeti is easily anthropomorphized since it's behavior can't always be explained. Jim hopes to run it for a few good short data runs, then run it until it into the ground.

C-130 Landing

We waited on the Tarmac while the crew removed the Jet Assisted Take Off units from the back of the plane. We then loaded into webbing benches strapped to the wall and stuffed in earplugs. The Herc flew south for a while before heading east inland towards summit. The sea ice stretched as far as we could see. We're intrigued by the possibility of hydroplaning a snowmobile from ice berg to berg, but that'll have to wait until our next trip up here.

Unloading at Summit

Our experience at the Summit consisted of running to find the 'pee flag,' then standing in prop-wash for 45 min as the plane unloaded fuel for the camp. We were happy to get back to Kanger, though apparently nobody figured out that we were supposed to eat. We got a couple of dehydrated meals from the crew here and headed back to our dorms in the science support building to boil some water and enjoy some subsidized scotch. Kevin and I are realizing our four days here could be pretty busy with writing, but we're planning to take a day and sleep in tomorrow.

Fuel bladders on sleds ready to go

Yeti on its own

2008-05-12T22:07:00.002-04:00

After our successful run yesterday, Jim was convinced that the robot was prepared for him to operated it on the traverse. This is great news because it means we'll get good radar data from crevasse zones, which were further out than we had the opportunity to go on this trip. We're also excited because it means that Kevin and I won't have to worry about getting Yeti home, which was a massive undertaking on the front end of the trip.

Today was our last day in Thule, which we spent the day teaching Jim the intricacies of Yeti's internals, including the embarrassing workarounds we were forced to make when working on electronics in the field. The system is robust though, and we expect that it will perform well once its our of our hands. We won't know for another 6 weeks or so, until the team gets back.

We celebrated by going to the gym and getting our our aggression with an automated tennis ball launcher inside a squash court, after getting tired on the rotating tread climbing wall, which we followed that with some Scotchernetting.

We'll be off the grid for a day or two, after which we'll hopefully have some videos of Yeti. We're both excited to get home at this point, see you all soon.

On the Cap

2008-05-11T19:11:00.008-04:00

We spent most of yesterday resting up and preparing to head out further up the glacier than we've been before. After a bunch of test runs yesterday, Jim was suitably convinced that yeti was up and working well enough to take it out further to run a course through some of the rougher sastrugi on the traverse route. We drove out to the third waypoint, towing Yeti on a sled behind the snowmobile and running the Tucker Sno-cat along side.

When we got to our test location, we got Yeti ready to go and pressed play. Pretty soon, it tacked north and veered about thirty degrees off of it's intended course. I groaned as Jim seemed thoroughly unimpressed before we manually drove it back on track and pressed play again. Within thirty seconds, it turned north again off of our track, and I started to bite my nails. We knew our controller worked from all of the other successful tests, so I guessed that our controllers might have drifted from being bumped around for on 10 miles on the drive out. We did a quick field re-calibration and held our breath. It worked perfectly, and Yeti drove off towards the first waypoint.

This exceedingly boring video gives a quick sense of speed and scale and records the first autonomous GPR record in history. That's a lot of qualifiers but we're excited.

The snow was soft and the sastrugi was relatively large, but Yeti handled it all. It did get stuck several times when it hit large but soft features at just the wrong angle, but that problem was the result of our small tires, and won't be an issue once we replace them.

The radar that we got back looked pretty good to us, though we're waiting to see what the experts say. It looks like the radio on Yeti has some interference with the radar, but that won't impede its detection of crevasses and can be turned off once we're done with testing and out of the prototype portion of the project.

Kevin and I are actually excited to be heading out at this point. The rest of the team has been great but we've been holed up for some absurdly long nights in the nerdery, and ready to see the sun go down again. We'll head up to the icecap summit on Tuesday on a hercules C-130 cargo plane, and figure out the plan from there. I haven't had time to cut all of our video yet, but I'll work on that and hopefully have it up by the beginning of next week.

Right before heading up the ice, yeti in tow

Kevin on his own

This was all Jim's idea, from a paper concept in 2004. He's glad to see it running at last.

Our workspace may not seem so bad from the pictures, but we're working 100 yards from a runway in a building in which they operate heavy machinery with diesel exhaust, which also houses a firing range, and next to our little aluminum pallet that we work on is a shelf of stacked HAZMAT barrels. We're lucky we're not out in the cold though, and after this, nothing can distract us.

Kevin seems to have a ridiculous fondness for his new ski goggles (seriously)

Video

2008-05-10T21:23:00.000-04:00

Here's a montage of driving out on the ice.

Preparations

2008-05-10T16:08:00.006-04:00

The last couple days have been some of the most frustrating but productive that we've ever experienced. Kevin and I just finished a 23 hour day, and have gone almost completely asynchronous from a normal schedule, and we've shifted to working from 11 am to 3 am. The beauty of doing this here is that we never have to experience the sinking feeling of working through a sunrise. Since most of our meals here are entirely identical, we have almost no reference for what the current time would ordinarily imply.

We've been furiously working to bring telemetry on line for our next test and have finally succeeded in getting the radio to talk to our computer. Yeti now sends back it's coordinates, time, GPS quality data, and it's next waypoint. What made this so frustrating was that when we added telemetry functionality to our working controller, the robot would wander in loopy circles and not seem to care about its next waypoint. This stopped being funny after hours of diagnosis revealed no major clues as to its cause, and we were only able to get it working properly by reducing the amount of data we sent. The system performs very well now, but without much of the code we've written.

We've also hammered out our last issues with our ground-penetrating radar, and have gotten that working perfectly. We expect that our next run will yield high-quality GPS-tagged radar data. Thanks again to GSSI for letting us use one of their radar units. Without that we'd never be here in the first place.

Today, we're preparing to run Yeti tomorrow on it's last major run, further out on the ice sheet. This will be a more complicated course over sustained and gnarly sastrugi, and we plan to be entirely hands off from start to finish. Yeti's batteries are our biggest concern now, as several of them have broken on us and only 5 1/2 out of the original 9 are working. Yeti should be able to finish the several mile course, but it'll be close.

We heard yesterday that we would have to leave three days earlier that expected, though we'll be getting back two days later! The only way to get home is by flying to the Greenland summit station and spending two days there, then flying back through Kanger which requires a two-day layover as well. We won't have access to Yeti so it'll be a mandatory rest that Kevin and I could probably use, though we'll miss GreenKey weekend at Dartmouth by a day.

More pictures on the way, stay tuned for tomorrow's results.

Field Day

2008-05-07T21:49:00.007-04:00

On Tuesday we took Yeti back into the field for a surprise run. We expected to have the day to work on our code and perfect its autonomous behavior but the rest of the team was heading into the field and with great weather we had to try out our first fully autonomous long-distance run.

From the base of the transition, we pressed 'play' and watched as Yeti climbed up the glacier towards its first waypoint about 3km up the icesheet. Kevin and I struggled to keep up, bogged down with the toolstation and backpacks full of gear. Yeti climbed through the sastrugi field with the largest features about 2.5' tall without getting stuck once, holding its bearing well as it bumped around the rough terrain.

About 2 km up the glacier we heard Allan heading up the glacier on a snowmobile, and he told us we'd have to cut it short since people were heading in for the day. We hoisted Yeti up on the crane from the Case tractor and brought it back to base. We spend the rest of the night coding, logging a 17.5 hour work day.

Our radar record showed us very little about the ice surface since we apparently had the gains set such that it ignored most of the first layer. Allan showed us how to set the radar accordingly, which we changed for Today.

Today we got up again at 7 and packed up to head out to the field again. This time we decided to use a snow machine, and found out how ridiculously helpful it is. Running with a laptop on ice has proven pretty difficult, but laptoping on the back of a snowmobile worked out extremely well.

This time, we pressed play and Yeti repeated the climb, this time making it the entire 3km to the first waypoint before turning around and heading to the second point at the bottom of the glacier. The radar data looks great as far as we can tell, though we'll have to take a closer look at it when we have time tomorrow.

We've learned a lot about the system at this point and are pretty close to the point where it would be viable to use in conjunction with the sno-cat for the GPR work on a traverse. We've identified the things we need to improve to get it to the point where it could do the majority of the survey work. We've got our hands full updating the code, but we're encouraged by the results and have had great success so far. Our next major milestone is a fully hands-off long range run with GPS-tagged radar data, and we plan to do this run on Friday.

Yeti with mount Dundas in the distance

Looking out over the fjord filled in with sea ice in the distance

A mind of it's own

2008-05-05T17:22:00.001-04:00

Today is exciting since we finally achieved all of our goals of the original project.

After a brutal day of coding yesterday, in which Kevin and I spend 10 hours figuring out how to send a number over the radio from the yeti to our computer, we conquered the ridiculous. What kevin thought would take him half an hour ended up taking the whole day. The details are not as interesting as the fact that this allowed us to troubleshoot the control system much more easily.

This morning, we fired up Yeti and fed it a GPS coordinate out on the Thule runway. Technically I think we're breaking a lot of rules by driving around and taking photos in a controlled area, but we haven't been shot yet so it's worked out. The first time we tried this, Yeti turned and drove away from the coordinate. A couple more runs revealed that it was not accurate but consistent. Kevin figured out that he had a sign error in his code which would make it run in the opposite direction. After reprogramming it, we gave it another shot and Yeti locked onto its target immediately and drove straight to it.

We spent the rest of the day making more improvements to the motor controllers which will extend yeti's driving rage significantly and eliminates the purr the robot used to make when stopped.

We'll be out in the field tomorrow so we'll have some more interesting pictures and video.

The Icecap

2008-05-03T21:30:00.006-04:00

I'll put the pictures up front, if you care about the details of Yeti's performance on the Icecap make sure to read to the end.

After pulling an 18-hour workday on Friday (sorry for not posting), we got Yeti ready for some testing on the ice. We were going to keep working on autonomous control but it became clear that that wasn't an option as everyone we came with really wanted to see it run around on the ice.

We drove off the base for the first time, up the 12 miles towards the ice cap. We passed the Thule Ballistic Missile Early Warning Radar System for which the Thule base exists, that gives us early warning in the event of Russian missile launches. The rest of the team have been setting up for the traverse at the base of the transition onto the icecap. A large section of the transition was groomed to give ample space to tow the fuel sleds, but this gave us a path to get down to the base of the ice sheet.

Me about 200' from the edge of the ice, which isn't visible.

Kevin in front of the Tucker. This beastly machine won't be necessary the next time NSF runs a traverse.

The Tucker with the frame assembly on the front for GPR surveying.

Part of the traverse cargo in front of the transition. This ramp of ice leads up to the icecap, the second-largest body of ice in the world after Antarctica.

Thule BMEWS

Kevin had a hellacious time trying to calculate a bearing from GPS coordinates with the small computer onboard Yeti and we're going to need another day of development before we'll be able to operate fully autonomously. I reworked the driving interface which gives us much better control and makes driving a lot of fun.

Kevin commented that it's probably the nerdiest hick sport imaginable to go out 'robot rock-crawling' but we justified it by calling it testing.

Yeti performs ridiculously well on rough and steep terrain and has exceeded our expectations in its ability to get over obstacles. When we took it out to the ice cap today, we were able to navigate sastrugi that was several feet high, though Yeti high-centered and got stuck on some sculpted blue-ice features that don't occur further up the glacier.

We drove on 2/3rds of our batteries, and this lasted for about 2.5 hours of driving, 1.5 km of which was up a 10-degree slope.

Overall, we're quite happy with how it performs and we'll be doing additional characterization of the power and drive system in the next week.

Running on Blocks

2008-05-01T20:37:00.005-04:00

We spent most of the day today working on code. This is the more interesting stuff for us, but harder to write about and less exciting for everyone else reading. We had an extremely hard time dealing with the slowness of our serial connection with the computer. The consequence of this was that every once in a while, the connection would drop the 'stop' command and the robot would keep moving. This was concerning for obvious reasons, so we spent an inordinate amount of time reworking the code to quash the issue.

We also got our GPS up and running and saw 4 satellites for the first time, and Yeti was able to interpret the GPS info for the first time which was exciting. We're now where we would have liked to be about 2 weeks ago, but we've been working around the clock as it's been.

Tomorrow we'll take Yeti outside to test GPS navigation and the new manual driving code. We only have one day to get up and running before we head up to the ice sheet transition on Saturday.

Shop Day

2008-04-30T20:11:00.006-04:00

This morning we found that our shop space is almost comically un-ideal, as we are situated between a hangar door that frequently opens to allow tracked forklifts to pass (at 1 mph) cooling the room to 10 degrees, and, I kid you not, an indoor simulation firing range in which soldiers fire gas operated M-16's at video terrorists and 90 decibel Turkeys. We don't really mind but though it was a pretty hilariously imperfect place to be situated.

We finished what we hope to be the last of the wiring, mounting, and other physical work on the robot, which is a huge step after almost 8 months of work. We'll be running Yeti tomorrow to test our GPS reception up here and try out or new code. We also built what we termed the 'Toolstation' for obvious reasons. This obnoxious platform allows us to sell peanuts while holding a laptop, batteries, radio, and antenna for fieldwork.

Kevin models:

Here are some pictures from yesterday.

Seeing the quad-track unload is absurd. Once outside of the plane, I would never believe you could get it off the ground.

Jim goes over the planned route and the crevasses marked on geocoded satellite imagery and photos taken from a helicopter.

Kevin plugs in our Truck. It's also 10:00 pm

Yeti in a crate.

On the ground in Thule

2008-04-29T16:36:00.008-04:00

This morning we headed into town for breakfast in the community dining room. The town of Kangerlussuaq consists of a population of about 500 inuit natives and the air force personnel at the base. The two populations are separated by the airstrip through the center of the valley. Apparently Kanger is green in summer, but we're not quite into spring yet so we're surrounded by dead grass and ice.

After breakfast, we suited up with cold weather gear from the NSF Polar Program stockroom packed up our bags, and drove back to the Tarmac to load onto the C5. Heavier by a few passengers and 15,000 lbs of additional cargo, we took off for Thule. The flight lasted only an hour, but the difference in climate in Thule was noticeable the second we stepped out on the strip. Unloading took several hours as we tried to be useful helping the National Guardsmen unload pallets. Watching the Case Snowcat download off the cargo ramp was an impressive sight. We knew this was particularly unusual since the Air Force guys and base personnel were also taking pictures.

Once again, our accommodations here are far nicer than we get back at home, and the Base Exchange is the only place I've seen that sells alcohol cheaper than New Hampshire. Kevin and I are still adjusting to the 5-hour shift in our sleep and work schedules and we won't be making use of that anytime soon.

I'll be posting pictures from today as soon as I can upload them, so check in tomorrow for more pictures. For additional pictures from those in this blog, follow this Link

Our first two days have taken us this far. The last seven months we've worked so that we'll be able to navigate the first several pixels of distance on the blue line towards the summit. Once on the ice cap, there won't be many crevasses but the transition zone can be quite dangerous.

Purpose of the Greenland Traverse

2008-04-28T19:52:00.000-04:00

This is the second post for the day so make sure to check out the one below.

Several people have asked us what the purpose of performing a ground arctic traverse is, so I'll devote a short post to addressing the question. Currently the Summit station in Greenland and the South Pole station in Antarctica are supported entirely by C-130 Hercules flights. The carbon footprint of supplying these bases by air is close to 1000 times greater than by towing the supplies overland on sleds behind a snowcat. Besides being inordinately expensive in fuel costs, the flights produce enough emissions that scientists have to work around the flights schedules to collect atmospheric data.

The folks objecting to the Antarctic traverse mission unfortunately missed the point entirely, misinterpreting the traverse as unnecessary expansion. The traverse team follows minimal impact guidelines, packs out 100% of the garbage on route. The traverse is simply establishing a route across the ice that is known to be safe.

Live from Greenland

2008-04-28T19:35:00.005-04:00

After one of the most ridiculously difficult roadtrips down to Stewart Air Base, we arrived in Newburgh to collect the full team and spend the night before our 6:00 wakeup. Our hotel was right next to the brand new Orange County Choppers shop. Apparently we missed the Aerosmith concert marking it's grand opening by a day....

Passing base security was a little easier this time, they waved us through after seeing one Army Civilian ID's, in contrast with the 45 minutes of bombsniffing we got last time. Hurry up and wait was the motto of the morning as we spent several hours waiting for the plane to prepare for takeoff.

The C5 was more impressive than we expected up close. We heard that you can spend a career in polar research without getting to fly on one. The passengers fly facing backwards in small and loud cabin at the top of the plane separated from the cockpit. The passenger compartment seems like an afterthought; a tumor on the cargo-hungry body.

The C5 upon landing

Kevin next to a snowcat loaded inside the C5

Loading gear at Kanger

We arrived in Kangerlussuaq after one of the most pleasant flights any of us had experienced. After several hours of loading additional cargo pallets on the plane, we headed to the science support station, located right next to the Kanger jail. The buildings are all brightly-painted prefab concrete boxes that Kevin and I decided are much more comfortable than our accommodations in Hanover.

Jim and Brad outside the KISS

Mark arranged a BBQ for everyone involved with the project, which was a rare opportunity for the NSF folks and the air force guys to interact.

It's 11pm now and feels like dusk. By the end of the project we should be experiencing 24 hours of daylight in Thule.

Tomorrow we wake up at 6:00 again and fly up to Thule where we begin working furiously to bring Yeti online in time for the traverse.

We're Back

2008-04-16T21:21:00.009-04:00

We're back online after an intense period of working on the bot. Over our spring break we heard that NSF accepted our impromptu proposal and decided to stage us in Greenland on a traverse connecting the Thule air force base with the Summit station in Greenland. The purpose of the trip is to resupply the Summit Station, and we'll be testing Yeti's effectiveness at detecting crevasses alongside a Tucker Sno-Cat with radar.

Kevin and I will be heading to Qaanaaq, Greenland (Thule) with Yeti, about as far north as we can possibly go. If you know how to pronounce Qaanaaq, please let me know. At the end of the winter, we had a working robot, but the user interface was rudimentary, the GPS functionality nonexistant, and the robot was not prepared to drive outside. With only two team members left working on the project, we've been working around the clock to get ready in time.

Our Carlon supplier informed us this week that the enclosures we ordered 7 weeks before would not be available until June. We pulled the order, spent a day in the CAD lab, and overnighted some stock material and after several days of breathing fiberglass dust, we ended up with a couple of sweet bulletproof fish tanks to protect Yeti's electronics in snow and -40 degree temperatures.

Ken Corcoran from GSSI came up to Dartmouth on Tuesday to deliver our SIR-3000 GPR unit and work with us to integrate the radar with the GPS and the wheel encoders. This took a monumental effort to get Yeti ready in time, and Kevin and I put in 30 hours in two days to get Yeti buttoned up and ready to go. We finished at 5:00 on Tuesday morning, took a quick nap, and met Ken at Thayer.

We ran into surprisingly few problems integrating the GPR unit with Yeti's electronics. Yeti's power board was able to supply the GPR with enough power and we were able to synch the GPR with Yeti's wheel encoders without issue. The one problem we faced was that the Garmin GPS we were using was never able to see more than three satellites, and the GPR requires at least 4. We're crossing our fingers that we'll have better luck in Greenland, since we've heard that satellite visibility is excellent where we'll be testing.

Kevin and Ken testing the GPR

Ken also helped us out by building a plate to hold the GPR antenna inside the tow sled which will help us out quite a bit.

Yeti is shipping out to get crated on a C5 transport plane on Monday, so we'll be racing in the machine shop the next two days to get everything entirely finished. Ken was justifiably not impressed with our 10-minute job on the towing mechanism, which was our lowest priority up to this point, so we'll be building a better rig to tow the radar

In our spare time, we've been updating the Yeti software to make the manual driving more intuitive and add the GPS functionality. We've been remarkably successful in getting this software to work so we're hoping that everything we develop in the week after we ship Yeti will work when we get to Greenland.

We'll be posting pictures and video from Thule so check back frequently.

Testing

2008-03-09T14:11:00.010-04:00

With another late night push until the daylight savings time exacerbated wee hours of Sunday morning, we put Yeti up on blocks, rigged the power wiring, mounted the radio and processor boards, fixed up the remote user interface program, and held our breath as we plugged everything in.

We fired up the GUI and radio and nervously twitched as I pressed the first drive command. We knew we would be there for a while diagnosing various problems with the programming, the radio link, the motor controller or the power electronics so we were completely unprepared when it worked. I'm not sure this has ever happened before in history but we plugged it all together and it drives perfectly.

After a quick team high five, we headed home to crash for a few hours before meeting Steve to test the radar interference this morning.

We found that there was basically no radar interference from leaked EMI from the robot, even when the radar antenna was situated between the two rear wheels. The radio transmission pulses did create a clear interference line on the radar image, but that was with the transmitter located 20' from the antenna. When running this in Antarctica the antenna will be miles away from the radar and only rarely transmitting if ever.

Here's a video from testing today

Mike's been working on simulating our bearing control algorithm. This video shows the yeti following a set of GPS waypoints with noise introduced to the system:

On the road

2008-03-07T16:16:00.004-05:00

With a late-night push, the team prevailed in overcoming all odds and finally wiring the rig, mounting our motors and gearboxes, and mounting the wheels. One might think this would be a simple endeavor but tight tolerances in the complex hub assembly have made us work pretty hard to get this thing put together.

Gus has been pulling some insane hours making her handmade PCB to supply houskeeping power to all of our electronics using a number of DC-DC converters. Our GPS, Sensors, signal processing board, and computer conveniently all run off different voltages, so Gus's board will feed each of those.

Kevin and I fine tuned all of our motor controllers such that the input voltage corresponds to a given motor velocity. This process was a little rough, it'll remain to be seen how well we can track a straight line when we start driving tomorrow.

This week Mike has been working on a simulation for our bearing control algorithms. We found that without any yaw-rate sensor we could get stuck in some pretty nasty looping situations where the robot's control system would force it to drive in circles. We ordered a Gyrocube that we'll be using for inertial navigation in conjunction with the GPS once we get that up and running.

Kevin tuning the motor controllers. This unassuming stack of hardware is about $5k worth of motors and controllers

Gus practicing her best coy look while assembling the hubs and gearboxes

Kevin working on the frame to get the wheels on

Gearboxes and bearing seats. Why does everything look sweeter when it's lined up?

Booyah

Gearing up for the Final Lap

2008-03-01T21:35:00.004-05:00

As the final week for our project approaches, we’ve been making significant strides toward the finish line. We’re working round the clock and like a well-oiled machine…or in our case, like robots.

We have finalized the designs for the enclosures, which have yet to arrive, and in their place machined plexiglass for testing. Eric spent many hours in the machine shop and using the CAD lab to layout the electronics within the enclosure…or as Eric would say, “I just spent five hours making rectilinear stuff with holes.” Kevin also kept him company helping to machine all of the spacers and angle brackets for supporting the enclosures and the electronics boards inside. Overall, the enclosures are coming together quickly and should be completely mounted on the backboards in a day or two. See the sweet picture below...

Last week, with the help of Professor Ray, we also finished up a thermodynamic model of the enclosures. At first we were a bit skeptical, but the model has proven very useful in deciding which insulation to use for our enclosures. The picture below is a prediction of the temperature inside the box in the worst case scenario: an outside temperature of -40 degrees Celsius and winds blowing at 20 mph.

The GPS is now working as well and we’ve got communication between the computer and the receiver. Unfortunately, we’re still having trouble locating satellites and so while the board has a nice blinking green LED that makes you smile…it still can’t steer the robot. We’ll give Novatel a call on Monday and hopefully they can impart their wisdom upon us.

Gus has also made some major strides in the past few days. She finished up the PCB last night after Thayer’s glorious Friday Beers and it’s now ready to ship off to a manufacturer. Next up is the copper power board, which will be machined in the shop and used for the remainder of the testing. In the spring, a PCB version of the power board will be made and used instead.

That’s it for now…But there will be plenty of updates in the days to come. Stay tuned.

Signal Processing, Power Bus and Power Board

2008-02-28T02:31:00.005-05:00

The signal processing board, as you can see above in it's not-so-finished state, is in the process of being designed using Eagle Layout Editor... The yellow lines you can see up there are all the connections that need to be made between each of the little red resistor and op-amp chips and green headers...It's called a 'rat's nest' for a reason. Anyways, the board is currently in a much-more-finished state as you can see below:

The job of the signal processing board is to take the raw output signals of the sensors, temperature, humidity, incline, as well as the motor controller output (in current and voltage for velocity and torque) and process them such that the computer can make out the position and status of the robot. Additionally, the computer's D/A output is run through the board to filter it before it goes back to the motor controllers.

Eagle is sweet. It is about 40000000 x 10 ^ inf times cooler than Cadence...Though the tool panel on the side is a bit weird and scrolling is entirely counter-intuitive and the library indexing system sucks, it is incredible to be able to drag the parts around the board and have it recalculate the shortest paths for common signals for you...totally sweet.

If all goes well, we should be able to order the board by Friday. Once the board has been ordered, time will ramp up again on the power board (which changes the battery voltage and current into smaller voltages for use by the computer, radio, gps, radar, sensors, sig processing board, etc.) The power board will be a CNCed two-sided copper-board, machined entirely hopefully over the course of a half hour...woohoo!...using a design in SolidWorks...wow! Thanks Pete Fontain! It's all designed and ready to go into SolidWorks...which, by the way, is the best program ever...it's a happier, friendlier world than Pro/E. I highly recommend the experience...I once wrote a paper about the CAD experience and the creation of the universe in a class on Jewish Mysticism...yay liberal arts...

Anyways, the power bus is also designed...We're going to use screw terminal blocks to secure the battery series packs in place. We were a bit worried about adding in a heat sink for the power diodes, but we had the sweet idea of using the copper bus block itself as the heat sink, since the case of the diode works as the terminal just like the pin out. It should simplify the design since the terminal blocks won't have to be machined out anymore...It will be pretty simple really. Fuse holders still need to be ordered, however...Once the funding switch gets turned back on that order will go out ASAP.

So that's about it with electrical stuff. Electronic stuff is going better I'm told...Yay for debugging the GPS...

Quicky

2008-02-27T23:50:00.005-05:00

We have Google Analytics on this blog and we've seen certain areas of the country where people seem to be very interested in the project but we have no idea who they are. Please let us know if you're one of the people that checks this blog frequently, particularly if you live in or near Cohoes, NY; or Billerica, MA. If you are interested in sponsoring the project in any way, please contact me: elas1@dartmouth.edu

Every step of the way we've encountered more obstacles but tomorrow should be the day that we get wheels on the bot and have something that rolls, even if it doesn't drive.

Drew made a breakthrough with the GPS tonight in determining why it doesn't work. He figured out that we needed a chip to convert the signal from the GPS into the standard RS232 that we need for the processor. We still have to get it communication properly but we'll be working on that in the next couple days.

Gus is laying out the signal conditioning board tonight and we'll be sending that out for manufacture by Friday.

Our electronics enclosures may be backordered for a while, so we'll have to make temporary boxes while we test our system.

Step by step

2008-02-22T23:16:00.004-05:00

We got the chassis back from welding today. Inky did an awesome job despite his claims that he might be hungover and that his eyesight isn't what it used to be. Overall we were very impressed.

We're shooting for full mechanical integration by tuesday of next week, and we'll keep you updated as we sprint towards the deadline.

Drew testing the chassis pivot (and looking like a tool)

You're sending signals

2008-02-21T23:19:00.002-05:00

This past week was chock full of successes on the electronics side of the project. We were finally able to get the motor controllers to work properly after many hours of playing with the loop gain and current limit adjustments and making sure we were operating in the proper mode. We can now precisely enforce the motor velocity with a control signal from our processor board.

We were also able to get the processor to communicate with a laptop using the radio modem and a serial connection. We then got a Java GUI rigged up that was able to send characters to the serial port and communicate with the processor. Bottom line, we can drive the robot by remote control over 10km away....once we have a robot.

Mike's been having a tremendously difficult time getting the GPS to work. The company tech support doesn't even know what kind of connectors are used to connect the board to anything else, so he had to rig up a custom adapter. We can't see any signals coming through the serial port, so right now we're scrambling to get that to work, otherwise we're dead in the water. Hopefully Novatel will return our calls at some point....

Picture me Rollin

2008-02-21T23:11:00.002-05:00

It's been a little while since the last post, we've been insanely busy trying to get Yeti's wheels on the ground. On the mechanical end, we've been held up for a week on the welding due to the repeated snowfall. Our welder has been working overtime keeping the snow-clearing equipment for Dartmouth running, so we've been nervously biting our nails as the deadline slid. The bulk of this got done today, so we should have the chassis and hub components assembled tomorrow.

We've ordered enclosures from Carlon to house the electronics on the robot. These will be arriving on Monday, so we should have most of the bot assembled by the middle of next week. This has been an interesting lesson on how to motivate subcontractors when they have no stake in the final product and you're not paying them.

More Pictures

2008-02-09T18:41:00.000-05:00

Fabrication Pictures

2008-02-05T17:48:00.000-05:00

Chassis Components

Chassis Components and Weld fixturing

Fixturing from the side

Pivot - Bushing and pivot surface

Motor Mount plates - these get welded into the ends of the motor housing tubes.

Hubs - Half completed hubs - These are being machined by Kevin Baron for us.

Drive Axels - these connect the hubs to each gearbox shaft

Drive Axel with custom Keyseat cutting broach. We've having fun working with both metric and english units. At least our robot shouldn't crash into mars if we make an error.

GSSI site visit

2008-02-03T14:58:00.000-05:00

On Friday morning the team had the opportunity to head down to the Geophysical Survey Systems Inc. headquarters in Salem, NH. Gus, Drew, Kevin, and Eric delivered a presentation on the GPR Robot project to several of the engineers and marketing people down there. The presentation consisted of a background on the purpose of the robot, the technical details of its design, and what we've accomplished so far.

After the presentation, we talked with the engineers for a while on the details of integrating their radar system with our robot.
The GSSI engineers were very concerned about both radar interference from the radio and the drive motors, and the radar reflections from the robot itself. It became clear that we'll have to do extensive testing to determine the magnitude of interference and undesired radar reflections, so it's a good thing that GSSI has generously offered to loan us a radar system for testing. We'll have to test the robot under different conditions to assess the interference.

Ken suggested taking the robot up to Tuckerman's Ravine on Mt. Washington in the spring so we can test the radar on snow over 20' deep. He also suggested 'air launching' the robot to isolate the radar antenna and robot from all other surrounding matter to get a clean picture of the reflections off the robot. Needless to say we're a little bit concerned about how to safely get our robot 50' in the air, but we'll look into various suspension schemes once we get to that point.

After the meeting, Ken took us on a tour of GSSI where we saw the manufacturing and test facilities. We got a hands on demo on how to use GPR and were all quite surprised at how easy it is to use. The pictures below were all taken with a b-side camera phone so the quality isn't stellar.

Living in the Machine Shop

2008-01-27T22:12:00.000-05:00

It seems like the perfect time to write a quick update. We’re entering the third week of the term and things are well on their way. We’ve spent the past few weeks chugging along in the machine shop and the robot is finally coming together. Eric took a photograph of a single half of the chassis attached to the welding fixture. With the welding fixtures done, our hope is to complete the welding at some point this week with the assistance of Inky down in Facility Operations and Management.

We’ve also made progress on the logistics front and have located at least one company that is willing to anodize the pieces of our robot. The plan is to anodize the aluminum chassis with a black hard-coat impregnated with Teflon, which will provide the chassis with additional strength and make it look downright sweet. In the words of the technical engineer at the metal treatment company, if the entire robot were to disintegrate, the Teflon shell would still be standing.

On the electronics front, we’ve also had major progress. Kevin got the computer up and running yesterday and was able to take input from a button and turn on an LED when the button was pressed. We also finally have the correct cables for the GPS radio and are currently working on the communication between the computer and the GPS radio.

After a brief scare with the motors and the motor controllers, we now have the motors up and running with the UltraLife batteries. The gearboxes were also finished by Neugart and are currently in the mail on their way to Dartmouth. Once we have the gearboxes, we can finish the keyhole cuts in the hub components and begin fitting everything together for the final assembly of the robot.

It's coming together

2008-01-20T22:44:00.000-05:00

We began fabricating the chassis with prodigious speed last week. The beginning of this week we'll be working on setting up the weld fixturing, and we'll hopefully be ready to weld the chassis by early next week. After an afternoon of scavenger hunting across campus, following rumors, tips, and people's vague recollections, we tracked down a guy named Inky, who we've heard is the best welder around. We had a brief chat with him in the FO&M shop, and it sounds like he knows a lot more than we do about heliarc welding so we're hoping he'll help us out.

One of the most significant lessons we've learned is the degree to which Murphy's law holds true. I won't bore you with the details, but dealing with a project this size make me appreciate how absurdly difficult it must have been to land a man on the moon.

Leonard Parker, our relentlessly heckling machine shop guru, has taken a serious interest in our project and has helped us out immensely. He's become interested in seeing the project succeed and has saved us with freakishly timely assistance, saving us from ourselves and supplementing experience for improvisation. Without him on board it's hard to see how we'd be able to finish on time with a well-constructed robot.

Leonard

We began fabrication last week by milling the gusset plates that are welded to the square tubing on both sides of the chassis. All of the main chassis components have welds somewhere on them, so we decided to use marine grade 5086 aluminum. This alloy combines decent yield strength with weldability and machineability. We were concerned about using 6061 since our robot will be deployed in temperatures cold enough to make the aluminum more brittle. The 6061 also loses much of its strength after welding, so we paid a little more and made the upgrade.

We spent many hours in the shop this past week just machining piece blanks from larger stock material. The motor housings were designed with 1/8" walls but we could only find 1/4", which means that each piece has to be laboriously turned down for three and a half hours on the lathe. It's a good thing we have a couple team members to tap each other out. We've found that there is a limited number of 25-minute lathe cuts one can perform before you want to clamp the chuck down on your head.

Our square-bar stock was .3 inches too short (from a 5-foot piece) so we were forced to order another segment. When that arrives tomorrow, we'll begin machining our chassis tubes and will be closer to getting everything welded.

We'll update on the electrical and control side of stuff tomorrow or tuesday.

Fabrication and Testing Schedule

2008-01-14T23:57:00.001-05:00

We've updated the schedule for getting stuff done. You can see our timeline broken down by the Electrical and Mechanical portions of the project.

Electrical Components

Mechanical Components

We're Back

2008-01-13T16:40:00.000-05:00

The team got back from break and started classes this past week. We've sat down and broken out everyone's individual responsibilities and we're rapidly coming to appreciate how much fun we have ahead of us.

All of the main components have arrived, so we began the process of figuring out how everything works. Mike started playing with the GPS and the Radio Modem to see what kind of signals we'll need to pass between these parts and our processor. Kevin has started playing around with the processor board and was disappointed to learn that in required a little more assembly than we initially thought.

I'm working on getting our motors from EAD to work with our motor controllers, and once this is done we'll be testing the motor controllers with signals from the processor.

Gus is currently designing a power housekeeping board that will take the 48 V from our batteries and step in down to 12V, 5V, and 3V as required by our various sensors and other electronics. After we design the schematic, we're planning to lay out the circuit and send out for a custom printed circuit board.

Scott and I are working to finalize the design of the chassis components and get the drawings sent off to Pete in the Thayer school machine shop, who will be helping us with the CNC machining.

Drew is working on contacting companies to get out chassis anodized. We've found that most companies don't have the capability to anodize parts this big, so we are continuing to look for alternatives. Drew is also looking for competent Aluminum welders so we can set up our fixturing and assemble the chassis.

We'll be updating this at least twice a week so check back regularly for updates.

Progress

2007-12-04T12:57:00.000-05:00

The team just finished our last week of classes and finals and presented our progress report to the review board, our project sponsor, and our advisor. With six perfectionists working together, the preparation was masochistic at times, but at game time, the team felt rock solid on both our progress and the presentation. Luckily the review board agreed, and we received great feedback from everyone involved, with respect to the technical aspects of the project, the management and project planning, and the presentation.

Looking forward to the next term, we're excited but remain apprehensive about the aggressive schedule required to have the robot fabricated for testing in mid February. If all goes as planned, we can achieve this goal but if there's one thing we've learned in the course of studying engineering it's that Murphy's law has a nasty habit of holding true at inopportune moments.

The flip side of this is that it will keep the project fun, so stay tuned as we prepare for an interesting ride.

Posts will be intermittent until the winter term begins in January.

Pro/E Renderings

2007-12-02T01:57:00.000-05:00

Here are a few pictures of subassemblies of the robot. Click on any of the pictures for a larger view. Yes, it's 2:00 am on a Saturday...

Full Chassis

Symmetric Half Chassis

Chassis - Left Side

Central Pivot Joint - Exploded view

Pivot Joint assembled

Wheel - Hub - Gearbox - Motor

Hub - Exploded View

Hub - Transparent

Parts Arrived!

2007-11-30T00:07:00.000-05:00

We're finally starting to get our massive quantity of various components from our various vendors. Many thanks to all the help from our company contacts who were able to offer us educational discounts for this project.

We received the wheels and rims today, we got extremely lucky that these wheels came on the market when they did. Apparently this is the first cast aluminum ATV rim in production and it has only been available for a year. This saved us from machining our own rims, saving us $1500 and two weeks of shop time.

It's finally starting to hit us that we'll be assembling this robot at the beginning of January and we're all excited to get out of the doldrums and into the fun part.

Wheels

Drive axle being machined on the CNC lathe

Sponsorship

2007-11-25T23:38:00.000-05:00

Ken Corcoran from Geophysical Survey Systems Inc. generously offered us a SIR-3000 Radar unit that we'll use while testing and developing the interface between the robot and radar control electronics.

The whole team will be heading down to the company headquarters in Salem in January to give a presentation on the project and learn about GPR from their engineers.

The team is excited about partnering with GSSI and we'll keep the updates coming as we figure out more.

SIR-3000

You can find more info about GSSI or the radar we're using from their website:
GSSI
SIR-3000 info

Turkey Summary

2007-11-23T18:11:00.000-05:00

At present, most members of the group are probably sleeping off a Turkey Coma from yesterday's feast, and resting up for the last push at the end of the Fall Term. Yet, the end of the Holiday is just around the corner so the purpose of this blog is to summarize our plans for the rest of the term.

Before the break, the group met up to talk about what we felt needed to be done before the end of the term. The group decided that we will finalize mass and money budgets for the robot based on the constraints of the grant and mass allocated in the Graves et al. design. At this point, most big-ticket items are ordered and the masses of most of the significant weight items are known. In order to assure that no surprises in space allocation arise, the group is also planning to build a mock up of the electrical control box to which everyone will add the parts they have been responsible for this term. In this way, the group hopes to anticipate any problems that may arise next term and ensure that parts will not have to be reordered. This is especially important because of the long delivery time associated with many of the ordered parts.

Other tasks we will be working on include the finite element analysis of the passive swing joint in the middle of the robot and addressing the fact that the design for the robot has been done in metric units (and our machine shop prefers English units). A hardware block diagram will be completed and a software diagram sketched out...Finally, the group will need to write a progress report and prepare a presentation for the review board on the term’s progress. All in all, it will be a very busy two weeks!

In the midst of my own tryptophan-induced stupor, thoughts of the robot seem a bit distant, but we are only days away from coming back to campus, and the project. Yet, it’s time (and probably well past time for me) to pull my thoughts back from Christmas and family to the real world.

Communications Parts Pictures

2007-11-16T18:15:00.001-05:00

Here are some pictures from the communications systems.

GPS reciever chip: Novatel OEMV-1

Wireless Modems: Maxstream Xtend

A chip like this one in the robot:

and a box like this plugged into my laptop to talk to the robot:

High Gain Antenna:

Thanks for your interest,

Robot Parts Are Expensive

2007-11-16T17:53:00.000-05:00

Most of our earliest efforts pertained to finalizing the mechanical design of the robot so that we could begin purchasing and machining parts. I am hoping to get our proposal power point presentation posted to this blog so that everyone can see what we are planning to accomplish.

As it turns out autonomous robots require a whole lot of expensive parts. We have spent the last several weeks searching the internet for parts. The main items are the following:

aluminum rims [wheels] (x4)
snow tires (x4)
electric motors (x4)
motor controllers (x4)

Batteries (x9)
Battery Chargers (x3)

central processing unit
incline and temperature sensors
GPS reciever and antenna
Radio Modem, Tranciever and antenna (x2)

Aluminum stock for machining parts

The majority of these items will be ordered over the course of the next week. I am working on the communications systems: the GPS reciever and the wireless radios. I have included images of them for your browsing pleasure. Hopefully my collegues will see fit to post images of the other parts.

As this post implies these parts are expensive. We have allocated nearly $1000 of our $1400 budget to purchase these items. This however covers all of our big expenses. The remainder of the money can be spent on miscellaneous parts and testing equipment.

Robot Background

2007-11-08T13:25:00.000-05:00

Each year, several Antarctic research expeditions travel across the Antarctic plateau in convoys of truck-sized tracked vehicles called snow cats. The lead vehicle uses carry ground-penetrating radar (GPR) to detect snow-covered crevasses that are invisible from air and pose a substantial hazard to ground vehicles. Snow cats cost around $250,000 and require massive amounts of fuel, an expensive commodity in antarctica.

The pupose of our project is to build an autonomous robot that will replace a snow cat to perform GPR surveys with the goal of crevasse detection.

Our robot will be:
-80% faster than a Pisten Bully snow cat
-28,000% more energy efficient
-1/20th the price
-easier to transport, operate, and service
-safer to operate

Robot Design:

Specs:
Length: 1.14 m
Width: 1m
Height: .57 m
Weight: 60 kg
Speed: 7.2 km/hr
Lifetime: 4.2 hr
Range: 33 km
Min. Operating Temperature: -40 degrees C

Detail of robot design featuring horizontal pivot and symmetric chassis.

Project Introduction

2007-11-08T00:52:00.002-05:00

We are a team of six Dartmouth engineering students building a robot to perform ground penetrating radar (GPR) surveys in Antarctica.

The team is composed of

Augusta Niles

Eric Trautmann

Scott Newbry

Drew Branden

Michael Zargam

Kevin Olds

We'll be posting updates and information as the project progresses. Please email me at eman@dartmouth.edu if you have any questions.