Wednesday, July 20, 2011

Days 4-5

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.


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