I haven't done that part yet.  That's part of what I'm asking (although I
may not have been clear about it).  I'm leaning toward some sort of optical
sensing one on each wheel/motor and compensate somehow.  It's important to
note that I have not done this type of interface (motors) yet.  Never
tackled PWM (although I have a good grasp of what it is).

If it helps, I am going to use L293 chip to drive both motors.  No real
current sensing, it's built-in.  So for distance and speed, I like the
optical idea.

John

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Olin Lathrop
Sent: Thursday, November 16, 2000 9:16 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [EE]: More motor control.


> QUESTION: The circuit will be PIC enabled.  Does anybody have
> recommendations on the best way to compensate for the difference in
> rotation?  I don't want the robot forever moving in circles.

I don't understand why your feedback loop wouldn't take care of this
automatically.  How are you sensing the rotation speed of the motors?


*****************************************************************
Olin Lathrop, embedded systems consultant in Devens Massachusetts
(978) 772-3129, olin@cognivis.com, http://www.cognivis.com

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