Nonlinear observer based force control of electro-hydraulic actuators

This paper presents a nonlinear observer based force control of single-rod hydraulic actuators. An observer based force control of electrohydraulic (EH) cylinders is proposed that does not require the cylinder position and velocity information. By treating the effect of cylinder position and velocity on the pressure dynamics as perturbation to the control model, we employ the perturbation observer concept to estimate the effect of piston motion and design a robust force control algorithm. The proposed method improved both the steady state and transient performance compared with traditional PID method. Simulation and experimental results are presented