Robust Position Tracking Control of Electro-Hydraulic Actuators: Elimination of Velocity Measurements

This letter presents a robust backstepping type controller formulation for the position tracking control of engineering systems actuated via electro-hydraulic actuators (EHAs). Specifically, a robust controller that does not require accurate knowledge of the system parameters and uses only position measurements is proposed. A filtered based approach is applied to remove the velocity dependency of the controller formulation. Stability of the closed loop system and the uniform boundedness of the tracking error signals are ensured via Lyapunov based arguments. The overall performance of the proposed method is illustrated, initially through physics-based MATLAB/Simscape studies, and then experimentally on a 1 degree of freedom (dof) EHA test-bed and a 2 dof robotic arm.