Design of robust PI controller for vehicle active suspension system with hydraulic actuator

Design of robust PI controller is proposed to control the dynamic behavior of vehicle active suspension system with hydraulic actuator followed by road disturbances. A graphical approach, using stability boundary locus in the (k_p, k_i) -plane is used to compute the PI controller parameters. The stability boundary locus in the (k_p, k_i) -plane is plotted by applying a gain-phase margin tester in the system to achieve the required gain margin and phase margin. In reality, all physical systems contain uncertainties. To take care of parameter uncertainties present in all physical systems, Kharitonov theorem is used.