Keeping two motors in sync

[Jared Russell]

Originally Posted by Ether

Could you elaborate on what you mean here by "integrating encoder values over time"? Could it be as simple as just using encoder counts instead of rate?

Yeah. The process variable for the steering controller in a differentially steered vehicle is heading, which is just the difference in encoder counts times a constant (to do a unit conversion). The constant is theoretically the inverse of the radius of the wheelbase; in practice you can tune it empirically to incorporate slip (if desired).

In the generalized motor synchronization case, using (left_distance - right_distance) would be fine.

Using a trajectory generator to make nice smooth, non-saturated position setpoint profiles is a great way to help solve the saturation/windup problem.

[Ether]

Originally Posted by Jared Russell

Using a trajectory generator to make nice smooth, non-saturated position setpoint profiles is a great way to help solve the saturation/windup problem.

Attached is a simple trajectory generator in Maxima. It inputs max accel, max speed, and distance to destination... and outputs equations for and a plot of speed and distance vs time.

Edit: moved attachments here.

[amesmich]

This is amazing. I am learned so much. Kevin, Ether, and Jared. You have helped more than you know. I wish I had more to say but I am busy reading whay you wrote and this site which has helped me wrap myhead around the variables and acronyms you have been using. Thanks.