I have a joystick and linear potentiometer that worked fine on the bench. The problem is the mechanical movement min-max is slightly less then the electrical movement. The motor is not stopping at full left or right because the feedback potentiometer is not being moved to the full electrical end points. Is there a setting I can change in the controller or can I add a resister or two to the signal or feedback wiring to offset the min and max electrical condition?
There is not much you can do on the feedback pot side.
The easiest is to limit the command you send. If you are using an analog joystick, you can do this by simply inserting a resistor between ground and the pot, and another between the 5V and the pot.