Abstract
Until now, an optimum finite preview control system utilizing finite future desired signals has been proposed in order to improve a control system performance. However, since the control system is constructed by only the design method for the optimum tracking control system, the robustness of the control system for the parameter variations of the controlled object and the disturbance signals is not acceptable for the practical applications. In this paper, new synthesis method for multiinput and multioutput robust preview control system is proposed. This method is based on the already proposed “error system method” which has been already applied for the design of the usual robust control system. After transforming the original state equations of the controlled object into the error system and defining a quadratic performance index, a tracking control problem consisting of the error system and the performance index is solved by usual optimal tracking control technique utilizing the priniciple of optimality. The designed preview control system consists of feedback part and feedforward part. The feedback loop consists of proportional actions and integral actions same as in the usual robust control system. Therefore, this preview control system is robust because of these proportional actions and integral actions for the parameter variations of the controlled object and the disturbance signals. Moreover, the compensating actions for the input delay time due to the processing time required to execute the employed control algorithm in the controller are included in the feedback loop. The feedforward loop represents the utilization of the future desired signal which is most important part in the control system. Some simulational results for this robust preview control system are presented in the paper for showing the effectiveness of the design method. As might be expected, the robustness of the control system for the parameter variations of the controlled object and the disturbances is satisfactory and it is shown that the utilization of the future desired signal is very effective to improve the control system performance. Extension of this method to the case of polynomial disturbance signals is easy.
