Proportional Control
A control technique that multiplies the error signal (the difference between actual and desired position) by a user-specified gain factor Kp and uses it as a corrective signal to the motion system. The effective result is to exaggerate the error and react immediately to correct it.
Changes in position generally occur during commanded acceleration, deceleration, and in moves where velocity changes occur in the system dynamics during motion. As Kp is increased, the error is more quickly corrected. However, if Kp becomes too large, the mechanical system will begin to overshoot, and at some point, it may begin to oscillate, becoming unstable if it has insufficient damping.
Kp cannot completely eliminate errors; however, as the following error, e, approaches zero, the proportional correction element, Kpe, disappears. This results in some amount of steady-state error.