Position Control Using A Servo DC Motor


Thread Starter


Does anyone out there know how to do position control with a servo dc motor. I am working on a senior design project for school and we were
sold a servo motor instead of a stepper. Is there anyway possible to use d-space(program in the computer that does sends out a -5 to 5V)
and integrate it with our motor. We would basically like to have the motor turn to certain angles at a slow speed.

Steve Bailey

Presumably that motor you were sold includes an amplifier that needs a bipolar voltage velocity command reference. The standard is +/- 10
volts, so you won't be able to command more than 50% speed in either direction. The motor/amplifier/feedback device combination will give you a closed-loop velocity controller.

If that is the case, then your program needs to generate the velocity command, ramping the value down to zero as the axis approaches the
target position. Remember from basic calculus that the integral of velocity is position. Your task will be to generate a velocity command
over time that the system is capable of following. Unless you have some method of getting the feedback from the motor into your PC, you will have only open-loop position control.