Disturbance Observer-Based Model-Independent Filtering Technique for Speed Servo Applications via Pole-Zero Cancellation Approach

Abstract

This article presents an advanced speed filtering technique for servo drives independent from the system model information with the reduction of the performance tuning difficulty. The contributions are two-fold: (a) the main filtering system outputs the filtered rotor position from the encoder measurement to recover the rotational speed of the rotor through the order reduction by the pole-zero cancellation property, resulting in the filtering error diagonalization, and (b) the subsystem, which forms the second-order disturbance observer, attenuates the disturbance to improve the acceleration filtering accuracy. The prototype 500-W servo drive validates the improvement in filtering performance under several load conditions.