Up to Summit

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

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

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

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

Preparations

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Fabrication Pictures

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

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

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

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

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

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

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

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!

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

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

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

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

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

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

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.