Smith predictor based fractional-order control design for time-delay integer-order systems

Abstract

The development of fractional-order controller design methods having a few tuning parameters in the time/frequency-domain is an attractive research topic. There are a few design methods using time-domain specifications. Considering a Smith predictor structure, a simple and efficient analytical method to design a fractional-order controller for time-delay integer-order systems is proposed, in this paper. The design procedure is based on time-domain specifications. The design requirements are the percentage of overshoot and settling time. To achieve these requirements, several tuning formulas are derived based on ideal closed-loop transfer function. The main advantage of the proposed method is that it has only two tuning parameters, which can be obtained using an explicit set of tuning formulas. To demonstrate the performance of the proposed controller and to compare it with those provided by several well-known design techniques, the proposed design method is applied to two simulation examples. Finally, a robustness test is carried out considering plant uncertainties.