Digital controller algorithm incorporating pseudo-acceleration feedback

A novel technique for obtaining an acceleration feedback signal is proposed to achieve fast and accurate motion control in a servomotor drive. The preview tracking operation is used to compensate for the inherent time delay associated with the sampling process of digital controllers. In obtaining an estimate of the ahead-error, a pseudoacceleration feedback control action is accomplished. Since actual measurement of the acceleration signal is not required, practical implementation problems associated with acquisition of the acceleration are avoided. The information derived is equivalent to a discrete-time approximation to the second derivative operation. Computer simulation results showed that the servo system with digital PI (proportional-integral) controller incorporating pseudoacceleration feedback achieved fast and well-damped response to changes in the reference command as well as drastic disturbance suppression performance