Optimization of dynamic anti-windup for non-linear robot systems with actuator saturation

Abstract

Optimization of dynamic anti-windup is applied to non-linear robot systems with actuator saturation. The static anti-windup scheme is expanded to a dynamic scheme based on passivity. The systems are represented as Euler-Lagrange systems, and a proportional-integral (PI) controller, in which the gravity term is cancelled by a non-linear compensation technique, is used. The goal of optimization is to minimize the saturated input, i.e., the difference between the control input and the real input, using the estimation function with a semi-positive convex function of the state variable of an anti-windup compensator and the saturated input. The proposed controller and its optimality are verified through experimentation and numerical simulation using a two-link robot arm.