Intelligent Output-Feedback Speed Tracking System for Servo Drives via Adaptive Error Stabilization and Order Reduction Approaches

This article exhibits an innovative intelligent output-feedback solution for the speed tracking problem in servo drives, aimed at reducing peak current as well as the reliance on sensor measurements, system modeling, and load information. The proposed output-feedback system adopts a conventional multiloop structure that operates without current measurements and offers the following three contributions: first, a model-free speed observer based on a low-pass filter using position measurements, achieved through an order reduction technique; first, outer loop intelligence that maintains critically damped tracking performance while lowering peak current levels; and third, a simple adaptive proportional-derivative control for stabilizing inner loop errors designed by an order reduction technique. Experimental validation of the system is conducted using a 500 W brushless dc motor prototype, demonstrating its effectiveness subject to the various load conditions.