Optimal control of a servo-hydraulic actuator plus time-delay via LQR approach

This paper presents an optimal PI tuning algorithm applied to a first order plus time-delay process via LQR approach. In the presented algorithm the Q and R matrices are adjusted by the natural frequency and closed–loop system damping ratio and finally the resulted algorithm is applied to a servo-hydraulic actuator with nonlinear dynamics. In order to apply the algorithm to the system and obtain the PI tuning gains, the nonlinear governing system equations should be replaced by simplified alternative equations. In the other word, high-order equations should be simplified. Then the simulation results of the nonlinear plant are compared to those of the related simplified model.