Accomplishments
This week, I worked on flashing and testing code on the Kontroller PCB to control the Kar with BLE. Additionally, I’ve been doing some fine tuning with the IMU code that Caitlyn wrote, and smoothing out transitions to/from dead zones. This is important to refine, given that we don’t expect full 360º rotations, but rather 90º-120º rotations for both the ICM and MPU located on different parts of the wearable device. Other than that, we were able to finally test driving the Kar on the ground, and evade obstacles by steering and varying acceleration.
Progress / Schedule
We are on track, and we have a working Kar PCB to demo for our interim demo. There’s also progress with the haptic motor, and we’ve been experimenting with different vibration modes. My biggest concern now is getting the backwards PWM motion working for the Kar. Because the servo steering provides a limited range of motion, backwards movement on the Kar would be necessary to have the user complete tracks or get past obstacles without external help. The Kar’s WP1625 ESC uses a FBR (Forwards/Brake/Reverse) mode, where 1000 µs – 1450 µs corresponds to backwards, roughly 1450 µs – 1550 µs corresponds to braking, and 1550 µs – 2000 µs corresponds to forwards, assuming a 50 Hz PWM signal. I’ll measure the PWM signal for backwards using an oscilloscope to make sure I’m generating the correct signal, and follow the troubleshooting steps for the WP1625 datasheet if I encounter further issues.
Next Steps / Deliverables
Next week, I will work on adding backwards motion to the Kar, and continue fine-tuning the roll, yaw, and pitch conversion to angles. If I have extra time, I’ll help with the haptic motor integration.