Fisher Price Motor Power

[Joe Johnson]

Originally Posted by vamfun

As a controls engineer, this was my first thought but from this thread it seems the problem requires motor speed to be of any use. When Al and I were pondering the Jaguar linearity vs frequency phenomenon, I had proposed a BackEMF motor speed project but never got around to doing it last summer. I wish I had so we could just use the CAN bus and motor voltage to create a current trip schedule without the use of an encoder.<snip>

Now we have gotten far afield but if you want a project to implement on the Jaguar, consider the following:

This paper (Closed-Loop Motion Control for Mobile Robotics -- by Rich LeGrand available for $1.50) makes reference to the idea of using Back EMF to control a motor. The great thing about it is that you don't need to http://www.chiefdelphi.com/forums/ne...ly&p=913687put any extra stuff on the motor to get PID control. FYI, Rich LeGrand is from Charmed Labs which hosts this example video that dropped my jaw.


If you want to learn more about how it works, look at this link from another cool robot website, Acroname.com. I think they really do a pretty good job of making the concepts understandable. Actually, Acroname.com is part of the way there already in that they offer an H-bridge with velocity feedback built in.

So... I want to see this built in as a feature of the Jaguar. You could command motor speed for any motor on the robot! Think of the well behaved robots you'd see if the default code implemented velocity control as the standard method move a drive wheel? Need a beater bar to move a a standard speed without having the fuss an muss of adding a sensor and implementing a feedback loop? no prob.

This would be a very big deal for FIRST robots.

For your consideration.

Joe J.