Trajectory planning for the tracking control of systems with unstable zeros

Abstract

In this paper, a trajectory control strategy for a nonminimum phase system is proposed. A continuous-time version of the zero-phase error-tracking controller (ZPETC), a well-known discrete-time feedforward controller for tracking control of a nonminimum phase system, is derived. The performance of the continuous ZPETC is further enhanced by adopting a specially designed sinusoidal trajectory to compensate gain error. The sinusoidal trajectory has a synergic effect on tracking performance when combined with the continuous ZPETC. The effectiveness of continuous ZPETC with sinusoidal trajectory is confirmed through simulation and experiment of a nonminimum phase plant, a single link flexible arm. (C) 2002 Elsevier Science Ltd. All rights reserved.