Introducing Virtual Axis to Path Control System Using Superficial Evaluation Term

Abstract

Presently, tracking control with high speed and high accuracy is seriously required in the field of robotics and machine tools. For the control problem, we previously proposed a preview control system which has a superficial evaluation term in its performance index, and we showed that the preview system is not effective for applying the problem in two cases. The first is when the tracking position is on the velocity vector of the desired signal. The second is when the desired signal does not change. In both cases, the term becomes zero, then the path error becomes large. To overcome the problem caused by the first case, we proposed intoducing an auxiliary superficial term into the perpormance index of the preview control system. In this paper, to overcome the problem caused by the second case, we propose the intoduction of a virtual axis to the system. The synthesis method for the new path control system is presented. To evaluate the effectiveness of the proposed control system, simulation studies are carried out. The simulation results show that the path tracking ability is markedly improved.