Residual vibration suppression of large-size flexible hydraulic manipulator under external disturbance with accurate positioning

Abstract

To reduce residual vibration with accurate positioning for a flexible hydraulic manipulator, this paper proposes a dual-impulse vibration suppression method to implement concrete pumping tasks. Through sealing up the load-bearing chamber and allow fluid exchange in the non-bearing chamber by individual metering control (IMC), a valve-based volume control method without position sensors is proposed to replace direct positioning control of the end point. Besides, a dual-impulse valve controller is designed for making an online tradeoff between vibration suppression and accurate positioning under a specific pumping posture. Based on only pressure feedback, the amplitude and the time width of the two impulses are determined via system identification in advance and vibration prediction in real-time. Experimental tests are carried out using a 13m-length hydraulic manipulator under three different postures. The test results show that the vibration caused by disturbance can be effectively reduced using the proposed method, and more importantly the position of the end point can be maintained accurately.