Title :
A model-based impedance control scheme for high-performance hydraulic joints
Author :
Bilodeau, Glen ; Papadopoulos, Evangelos
Author_Institution :
Dept. of Mech. Eng., McGill Univ., Montreal, Que., Canada
Abstract :
Impedance control of a hydraulic servoactuator joint system is discussed. Impedance control imparts a desired behavior to a system, rather than controlling position or force individually. Due to nonlinear properties of hydraulic actuators, impedance control is difficult. The control strategy presented involves a combined feedforward and feedback control. An impedance filter modifies a desired trajectory according to a specified behavior. The modified trajectory is fed to a reduced-order model of the servoactuator hydraulic joint in order to reduce the effects of the nonlinear hydraulic dynamics. Position, velocity and pressure feedback loops compensate for the unmodeled dynamics. Simulation results show the strategy to be promising in providing impedance control to the joint. Special attention is given to the careful choice of impedance and control parameters to ensure smooth transition between contact and non-contact regimes, and to avoid actuator saturation. The developed controller is useful in achieving a desired behavior of hydraulic manipulators in contact tasks. It will provide the basis for a robust impedance control of the SARCOS high-performance hydraulic manipulator
Keywords :
actuators; feedback; feedforward; force control; hydraulic control equipment; manipulators; position control; pressure control; reduced order systems; servomechanisms; velocity control; SARCOS; contact regime; feedback loops; hydraulic manipulators; hydraulic servoactuator joint system; impedance filter; model-based impedance control scheme; noncontact regime; nonlinear hydraulic dynamics; reduced-order model; unmodeled dynamics; Computer integrated manufacturing; Control systems; Feedback control; Force control; Hydraulic actuators; Impedance; Manipulator dynamics; Mechanical engineering; Robust control; Torque control;
Conference_Titel :
Intelligent Robots and Systems, 1998. Proceedings., 1998 IEEE/RSJ International Conference on
Conference_Location :
Victoria, BC
Print_ISBN :
0-7803-4465-0
DOI :
10.1109/IROS.1998.727480