pic: Makeshift Kiwi Vex-FTC-FRC hybrid

[Andrew Schreiber]

Originally Posted by Alan Anderson

You want "heading hold" when the driver is not commanding a turn, right? Use whatever joystick input commands the turn to turn off heading hold whenever it's not at neutral, and turn it back on again after the turn is finished. That could be as soon as the joystick is back at neutral, or it could be slightly delayed to account for the robot's inertia. See how the driver likes the handling with various amounts of delay in the reactivation of heading hold mode.

So, we attempted this, however as Bill Nye reminds us constantly, "Inertia is a property of matter". The heading lock controller (tuned) would take over as soon as we let go of the stick and it would oscillate because the gyro reading we were going to was behind where we actually were (because robot has inertia when it spins). A delay would resolve this issue. I was curious if there was a better way than that. We thought about sampling the gyro rate and if it was 0 and the commanded rate was 0 we could enable heading lock. As it stands, we drive so little in any given match (HP loader) that it wasn't an issue.

Other approaches I thought about doing but in the end just went with the simple "hold this to lock heading" :

- PID controller on gyro_rate
- Settling time
- Scrapping it and saying "back in my day we didn't have fancy gyros to hold our heading, we did it uphill, both ways, with drill motors"
- Telling the mechanical folks we were never turning and all systems needed to be on a turret