Mecanum - use of gyro

[keericks]

Originally Posted by mwsmith78

Lots of posts since my last one ... I will try to knock off all the questions.

Using 6" Mecanum wheels with tapered rollers (from AndyMark). Wheels are correctly mounted. The robot drives correctly w/o PID loop - although it does tend to have rotation error. Given that it works well before attempting closed-loop control, I believe that points to the software.

If I understand correctly about the PID post - the I & D gain values are time constants and for tuning purposes should start HIGH and work down. Meanwhile, the proportion gain should start low and work up. That may explain why we were having trouble tuning. When we inserted I and/or D values, we started very small. If we want it to function as a P-only loop, is setting I and D to zero correct?


http://www.youtube.com/watch?v=KL7iZXCRtPw

In the video above, I notice the person pushing the robot and it responds to return back to a specific pointing direction. Is this based on vision camera, gyro, wheel encoders? Thanks!