A design method of perfect tracking control for discrete-time systems using multirate control

This paper presents a design method of perfect tracking control for discrete-time systems based on multirate control. Generally, perfect tracking control schemes cannot be applied to nonminimun phase plants because of unstable pole-zero cancellations. Some methods that are applicable to nonminimum phase plants have been proposed, however, the following problems are left unsolved: limitations to plants and uncertainty of design freedoms. We propose to use multirate control systems and state feedback schemes for perfect tracking. Since the method has been stated in 2-degree-of-freedom control techniques in this paper, it is clear how the design freedoms will be reserved after the design of tracking control. Basic techniques of this scheme have been presented, however, they cannot be applied to nonminimum phase discrete-time systems. The techniques we proposed are applicable to nonminimum phase discrete-time systems. Finally, computer simulation results are presented.