Joe McCauley wrote:
>
> I thought the following would work by controlling both position and speed.
>
> 1. Before starting the motors store the positions in position tracking regs.
> 2. In the timer routine add (or subtract depending on direction) the speeds
> requested
>    (encoder counts/timer interval) to the position tracking regs for each
 motor.
> 3. Subtract the actual position from the position tracking reg to get the
> position
>    error. This value will be + or -.
> 4. Either
>         a)Add or subtract a constant from the dac value to reduce the error.
>    or
>         b)Add the error value to the dac value to reduce the error.
>
> I have tried this with no success. Does anyone have any better ideas?

Use the relative position as an input to the summer in the control
control loop. Cross couple the control loops. Simple effective..


Walter Banks
http://www.bytecraft.com