In our Saturday afternoon test in Area A Sting 1 crashed head-on into a concrete barrier. The front sensor mount was bent severely and pushed into the front of the vehicle. Fortunately the protection offered by the design and strength of the sensor mount saved the sensors.
After assessing the log data we determined the cause of the accident was a failure in the communication link between our GPS/IMU and the main control computer. Without “pose” information the robot could not know that it was moving.
Recovery: Tartan Racing helps out
Our first order of business after the accident was to assess the damage and develop a plan, and we needed to fix the problem that caused the accident in the first place. The GM mechanics with Tartan Racing (CMU & GM) came well equipped to the site, and were eager to help us out. With their help we cut the main sensor mounting plate out, bent the metal back into alignment and welded everything back in place.
We give a big THANK YOU to GM and Tartan Racing!
The loss of comms between the GPS and the control computer could have occurred in several places, including the computer’s hardware, the linux serial drivers, or our code. We have circumvented the first two possibilities by installing a serial to USB converter and we access the GPS via USB. On the software side we added checks to make sure that pose information is streaming in, otherwise the robot brakes and reboots the computer.
October 29, 2007 at 1:28 pm |
Wait, shouldn’t the LIDARs have kept it from hitting the wall? Were you only running with inertial sensors? WTF guys! No visual/LIDAR odometry?
Hope you get everything under control, good luck!
-Andy
October 29, 2007 at 7:48 pm |
Yes, the LIDARs did pick up the wall. The issue is that the pose estimator is essential to control; without knowing its pose with respect to the wall, the robot can’t know what to do. In fact, looking at the data from the robot’s point of view, the wall hit it.