Discrete-time PIDA controller designed by Kitti's method; A third generation

Abstract

This paper proposes the design of Discrete-Time PIDA (Proportional-Integral-Derivative-Acceleration) controller. Once, the satisfied PIDA controller in Continuous-Time system is obtained. Then, just discretises it by using trapezoidal approximation or bilinear transformation, the Discrete-Time PIDA controller is easily achieved as well. The root loci of the closed-loop systems are circular shapes in both s-Plane and z-Plane implied that increasing of the open loop gains, the faster and smaller in percent overshoot can be obtained. Comparing among three generations are shown that the third generation of Discrete-Time PIDA controller is the simplest way in design without the difficulty to place the zeros of the controller in z-Plane as in the second generation when the sampling time is too small.