Robust Hydraulic Position Control based on Uncertainty and Disturbance Estimation

This paper presents a robust hydraulic position control with perturbation estimation. In hydraulic system, there are perturbations such as parametric uncertainty due to variable fluid properties depending upon temperature, nonlinear relation between input signal, flow rate and load pressure of servo valve, external disturbance and hard-to-model forces inside cylinder. Therefore, these perturbations should be estimated precisely to guarantee robust performance under the uncertainties and disturbance. In order to achieve this aim, a modelling of the hydraulic servo system is performed firstly. As second step, the perturbations are analyzed based on the modelling. Thirdly, the robust controller based on the uncertainty and disturbance estimation (UDE) is designed to assure the tracking and estimation performance. Finally, the effectiveness of the hydraulic position control with the UDE based control is considered by investigating simulation results. The simulation is performed under variable conditions by using AMESim.