This week, I focused on getting the robot to run headlessly, with all the sensors, the battery, and the Jetson entirely housed on top of the Roomba. Jai started by CADing and laser cutting acrylic panels with holes for the standoffs, in addition to holes for the webcam and the LIDAR. After getting the battery, we realized that the DC power jack for the Jetson had a different inner diameter than the cable that came with the battery, which we fixed via an adapter. Once we confirmed the Jetson could be powered by our battery, I worked on setting up the Jetson VNC server for headless control. Finally, I modified the Jetson’s udev rules to assign each USB device a static device ID. Since ROS nodes depend on knowing which physical USB device is assigned to which ttyUSB device, I created symlinks to ensure that the LIDAR is always a ttyLIDAR device, the webcam a ttyWC device, and the iRobot itself as a ttyROOMBA device. Here’s a video to the Roomba moving around:
https://drive.google.com/file/d/1U68VRGrZiqcw5ZbmErxF-N3jlftXx110/view?usp=sharing
As you can see, the Roomba has a problem with “jerking” when it initially starts to accelerate in a direction. This can be fixed by adding a weight to the front of the Roomba to ensure equal distribution (for example, moving the Jetson battery mount location could do this), since the center of mass is currently at the back end of the Roomba.
We are making good progress. Ideally, we will be able to construct a map of the environment from the Roomba within the next few days. We are also working in parallel on the OpenCV + path planning.