Resolved-Mode Teleoperated Control of Heavy-Duty Hydraulic Machines

Abstract

This paper addresses the control problem for a class of heavy-duty hydraulic machines in order to achieve coordinated motion control of the implement. A model and sensor-based control algorithm is proposed which is applied in conjunction with closed-loop components. The algorithm is basically a feedforward load compensating scheme which uses the measured hydraulic line pressures along with the appropriate portion of the hydraulic model to control the joint velocities. The effects of nonlinear dynamic coupling between the links, loading, coupled actuation and power limitations are compensated in this technique. The closed-loop part consists of PD components. A knowledge of some hydraulic parameters is the only requirement of this control scheme. The proposed approach has been examined through simulation and is supported by experimental evidence. The experiments were performed on a Caterpillar 215B excavator. The control program is written in the C language, running on a computer system which is interfaced between the human operator and the machine.