PI and PID controllers tuning for integral-type servo systems to ensure robust stability and controller robustness

The paper derives PI and PID parametric conditions to guarantee the robust stability of the closed-loop system with respect to parametric variations of plants used in the case of integral-type servo systems. In addition, parametric conditions are obtained to ensure the controller robustness. Then, the parametric conditions are expressed as recommendations for the choice of the design parameter in the case of PI and PID controllers tuning by the extended symmetrical optimum method. A case study including experimental and simulated results illustrates the parametric conditions and design recommendations.