Joint space controller design for electrohydraulic servos

This paper focuses on the joint space control of mechanical systems with electrohydraulic servos. Using mechanism inverse kinematics, desired Cartesian trajectories yield desired actuator trajectories, which are fed to a novel model-based controller. Rigid body equations of motion and hydraulics dynamics, including friction and servovalve models are employed. The developed feedback controller uses the system dynamic and hydraulic model to yield servovalve currents. As an example, the developed controller is applied to a single degree-of-freedom (dof) servomechanism. Identification procedures employed in estimating the physical parameters of the experimental single dof servomechanism are discussed. In contrast to other approaches, here, force, pressure or acceleration feedback is not required. Simulations with typical desired trajectory inputs are presented and a good performance of the controller is obtained.