A general framework of coordinated motion control subjected to actuator saturation

Abstract

A general framework of motion coordination of a two axes system in the presence of actuator saturation is proposed. The framework includes three parts: feedback controller, feedforward controller and online trajectory planner. The feedback controller is designed using an anti-windup design to reduce the degradation in performance of each axis. The discrete time zero phase error tracking controller (ZPETC) is used as a feedforward controller. The online trajectory planner is for maintaining the contouring accuracy by assuring not to saturate either the X-axis or the Y-axis actuator. The desired outputs for X- and Y-axis are given as sequences of points. When the actuator of any axis is predicted to saturate, points are inserted in the original sequence to slow down the motion. The effectiveness of the proposed framework is studied by simulation of a two-axis Cartesian positioning system.