Traction Control for a Turning Tank-Drive

[Rick Wagner]

Originally Posted by DanL

How's this for some brief thinking?

1. Measure wheel rotational velocities (eg wheel encoders).
2. Assume no-slip condition, and calculate force vectors exerted by each wheel. Estimate robot-trailer CoM, and use vector arithmetic to calculate assumed torque around the CoM.
3. Using a gyro (needs to be right on the CoM?), calculate actual angular acceleration.
4. Compare actual angular acceleration to expected angular acceleration (calculated from torque in step 2) -- this is your traction control system's wheel-slip-error measurement. If actual angular acceleration < predicted angular acceleration, you're slipping and you need to cut power.

Does this sound legit to you more mechanically-inclined people out there?

How about the process of integrating linear traction control with angular traction control? What kind of weird dependencies to people see?

Your thinking on that seems sound, but as you can't "track" (no slippage condition) and turn, by definition, as you mentioned, I am not sure it will lead to a performance inprovement. Moreover, I think all traction control schemes will run into problems when pushing other robots or being pushed, and could have some unintended consequences. That is, turning and pushing could give incorrect results, decreasing performance. Perhaps a button on the control panel might be advised so the pilot can disable (toggle on/off) traction control for pushing and turning scenarios.