Discrete time robust integral servo with PID × (n-2)/2 Stage PDA Controllers for unstable systems

This paper presents a design method for robustness stability results of unstable systems using forward controller employed to PID × (n-2)/2 Stages PDA Controllers which applied to integral servo problem, both continuous and discrete-time control systems, the root loci of this design method are shown the robustness results with the excellence transient response of this closed loop systems, moreover, in case of increasing controller loop gain, the system is still robustly stabilizable with better performance.