Comparison of acceleration control and pressure feedback for active damping improvement of hydraulic manipulators

Abstract

The active damping compensation methods based on acceleration control and pressure feedback are two powerful solutions for vibration reduction of hydraulic robotic manipulators. Especially taking into account the existence of external disturbance, the damping effects of the two methods are compared in this paper. It is disclosed that additional dynamic behavior is introduced by pressure feedback due to variation of zero location and open-loop gain, which leads to large overshoot and slow convergence. Using acceleration control does not have this additional behavior and just contributes to improving the damping performance. The mathematical model is established considering the system with an asymmetric cylinder. A nonlinear simulation model is conducted for case study of a 3-DOF robotic manipulator. Through theoretical analysis and numerical simulation, the result indicates that acceleration control is considered as a better method for hydraulic manipulators to reduce vibrations and reject disturbance, while the reliability of acceleration sensors should be improved furthermore for harsh applications.