Quote:
Originally Posted by sgreco
These could also be mechanical problems...What motors are you using for steering? What's the gear ratio from the steering motor to the module?
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We are using window motors and the gear ratio is Motor:Wheel = 18:32
Quote:
Originally Posted by apalrd
How exactly are you relating joystick position to wheel position?
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We are using one joystick to control the wheel position. We used asin and acos to calculate desired angle and speed. From there, we use desired values to calculate the errors for PID.
Quote:
Originally Posted by engunneer
How are you calibrating the PID? Are you able to command a "step move" or velocity profile, then graph the "commanded" and "actual" positions?
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We are using LabVIEW to calibrate PID in realtime.
Quote:
Originally Posted by engunneer
Also, I would recommend tuning the two sides separately. Ideally they are identical, but if they aren't having the ability to tune them individually could keep you with a running robot in a pinch. The main goal is that they have the same /response/ which is that they react to a control signal in the same amount of time and move the same amount. Sometimes one side will need more P than the other (i.e. if the CG of the robot is not centered between them), or more I (if you have a bad bearing or one motor is not as well greased as the other)
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We do have two seperate(but identical) PIDs for each side. Left side of the motor turns fine with PID(with some exections) but right side of the robot takes longer to adjust itself.