Usage of pitch rate in wheelie mode

[aelmiger]

What is the reason for calculating the pitch rate using (pitch_rate = current_pitch - last_pitch) for the D term?
I would think that using the direct gyro output is a faster and more reliable way of getting the pitch rate. Using the derivate of the pitch induces delays and filters that are (to my knowledge) not ideal in a D term.

vesc_pkg/vl_bike_39p/code_stm.lbm

Line 518 in 058d879

(var pitch-rate (/ (- pitch-deg-last pitch-deg) dt))

[vedderb]

Good observation!

The reason I didn't do that is that I wasn't sure if get-imu-gyro took the rotation of the IMU wizard into account, but from having a look at the code it seems that it does.

Another reason to not use get-imu-gyro is that it will be an instantaneous sample potentially suffering from aliasing, whereas the current approach will be the average rate since the last sample. Even so the raw gyro value might be a better choice as it will be inherently more stable and minimizing delay might be more important than avoiding aliasing. I will give it a try and see if there is any difference. Plotting the pitch rate gives a nice graph with low noise for the current implementation, so I don't think there will be much difference.