Using Control Loops to Tune Servo Motors

Tuning maximizes the performance of your servo motors. A servo system uses feedback to compensate for errors in position and velocity. For example, when the servo motor reaches the desired position, it cannot stop instantaneously. There is a normal overshoot that must be corrected. The controller turns the motor in the opposite direction for the amount of distance equal to the detected overshoot. However, this corrective move also exhibits a small overshoot, which must also be corrected in the same manner as the first overshoot.

A properly tuned servo system exhibits overshoot as shown the following figure.

The amount of time required for the motors to settle on the commanded position is called the settling time. By tuning the servo motors, you can affect the settling time, the amount of overshoot, and various other performance characteristics.