Proportional Gain (Kp)

Determines the contribution of restoring force that is directly proportional to the position error. This restoring force functions in much the same way as a spring in a mechanical system.

For each sample period, the PID loop calculates the position error (the difference between the instantaneous trajectory position and the primary feedback position) and multiplies it by Kp to produce the proportional component of the 16-bit DAC command output.

The formula for calculating this proportional contribution is as follows:

An axis with zero or too small a value for Kp will not be able to hold the axis in position and will be very soft. Increasing Kp stiffens the axis and improves its disturbance torque rejection. However, too large a value of Kp can cause instability.