This week was focused on completing the drive system for the vehicle. This involved getting some more refined code for the Arduino and Jetson Interface. The serial communication now works for this portion of the project so the Jetson can tell the vehicle how to move.
This week I also worked on integrating the IMU into the system for localization as well as come up with a way of doing odometry. As far the IMU goes, I have be able to develop code that provides displacement; however, as anticipated there is considerable noise in the system. I used a few techniques to mitigate this noise and found that with a sampling rate of 20hz, the IMU would be about 20cm off within a 1 minute of running. This is somewhat reasonable, but not optimal so we turn to odometry for slightly better results . In particular, we want to integrate an optical wheel encoder for two rear wheels of the vehicle to determine the displacement of the vehicle. By measuring the RPM we should have a good idea of displacement. Since we are using an encoding method that only provides speed and not direction, we can rely on IMU gyroscope data to provide us with that.
The new batteries also came this week and we were able to run a stress test on the system. This included using the UEBC device to power the Jetson. For the stress test I ran the motors at full speed while running some high intesity gpu benchmarks on the Jetson. The battery was able to last longer than 1 hour while doing this. This solution worked well so we can reliably use only one battery for our vehicle.
With the addition of the new batteries and planned odometry I also had to update the CAD model to accommodate the design. I designed a holder to keep the batteries in place and need to add mounts and cutouts for the optocoupler encoder devices.
Lastly I took the car for a test run on the track with some boxes to see how the driving would work on the track environment. I found the the turns are a little slow due to the higher resistance on the track surface. We may have to account for this by try to turn early in the path planning.
Next week we will try to have the vehicles done including the camera mounts and all design portions touch on above. I also want to transition fully from the vehicle mechanics to the communication and path planning/localization.