Method to apply virtual spring-damper hypothesis for a redundant hydraulic manipulator

This paper proposes a method to verify the performance of a redundant 4 degree of freedoms (DOF) hydraulic manipulator when Virtual Spring-damper (VSD) algorithm is applied. It is combined with a control based on the VSD algorithm proposed by Ari-moto et al. To verify the applicability of VSD algorithm to the hydraulic robot manipulator of redundancy 4-DOF, we conducted an experiment to tracking repetitive circle motions of 0.2 m radius to the Y-Z plane in 3.5 seconds. To check the control performance to all directions, the experiment was conducted to the repetitive circle motions which are sloped to 30 ° to the X axis. The effectiveness of the proposed control scheme is demonstrated in experimentation with the 4-DOF manipulator.