A discrete-time robust composite nonlinear control approach to motor position regulation

This paper presents a discrete-time robust nonlinear control scheme to achieve fast and accurate set-point tracking for servo systems subject to actuator saturation and disturbances. The control scheme is built on the framework of composite nonlinear feedback (CNF) control, which implements a dynamically-damped closed-loop system to achieve a fast response with low overshoot. A disturbance-rejection mechanism is also included, which adopts an extended state observer to estimate the state variables and disturbance simultaneously for feedback and compensation. Practical application in the position servo control of a permanent magnet synchronous motor is given to demonstrate the effectiveness of the proposed control scheme.