Modern Control Design for a Variable Displacement Hydraulic Pump

In this work robust control methods are used to design and analyze control systems for a variable-displacement hydraulic pump. More accurate uncertainty descriptions are derived by using an uncertainty model with some structure as opposed to an unstructured uncertainty model. The system studied includes one variable-displacement swash-plate hydraulic pump with a constant drive speed model. The input to the system is the current actuating the control valve position, while the system output is the discharge pressure of the pump. A PD controller and an H-infinity two degrees-of-freedom controller were designed. Frequency domain analysis compares the robustness of the two designs. Time domain results show that performance of the PD controlled system is better than the two degrees-of-freedom controlled system. Time domain simulations also show improved robustness to parametric variation from the modern control method.