Sampled-data Control System Design Using Reverse Element

Abstract

In this paper, the authors deal with one method for the control of sampled-data control systems. In contrast with ordinary sampled-data control systems, the polarity of the control signal is reversed at several instants in every sampling period. By deciding the instants properly, the finite settling time response can be obtained. Especially, for a step input, it is shown that the system error can be reduced to zero in one sampling period, irrespective of the order of the controlled element. Furthermore, the compensator is simpler than that for ordinary sampled-data control systems, because it consists only of a sampler, a hold element, and a reverse element which reverses the polarity of the control signal. Even for a controlled element with a symmetric saturation characteristic, the settling time has a finite value. Moreover, it is shown that the reverse element can be used along with an ordinary compensator containing delay elements, and that the settling time can be made shorter. The response for a random input is also analyzed for a typical sampled-data control system with a reverse element.