Novel control algorithm for rapid and precise positioning

This paper investigates the positioning technology of a control system using an optimal control method. In this method, the control algorithm is based on minimization of a quadratic performance index, which consists of the position error and the weighted derivative of the error during a specific time interval. Minimization of this index allows us to obtain the optimal step control input command. It is shown that the control algorithm is efficient for positioning and simple for on-line implementation. The stability of the step control system is analyzed by the root locus method, and a means of selecting both the sampling period and the weighting matrix according to the specifications of the system is presented. Comparisons of the proposed control algorithm with bang-bang control and the optimum regulator problem are made. Also, a track-seeking servo control system of an optical disk driver is used to illustrate application of the proposed control method.