Coordinated and Force-Feedback Control of Hydraulic Excavators

Abstract

The human interface of a Caterpillar 325FB fellerbuncher was modi ed to allow the operator to use (i) a 5-DOF joystick, and (ii) a 6-DOF magneticallylevitated joystick with sti ness feedback. While the operator commanded the velocity of the endpoint, an onboard computer system managed total system power, solved the inverse kinematics, servoed the joint actuators, and controlled the magnetically-levitated joystick. It was found that there were signi cant bene ts to single joystick endpoint velocity control including smoothness of motion, less damage to product (trees), and ease of operation. Controlling joystick sti ness as a function of endpoint force, was found to be both a stable and e ective form of feedback for a system where joystick position maps to endpoint velocity. Two di erent hydraulic systems were implemented and evaluated. The rst used valve control, as in a standard excavator. The second used hydrostatic control, by variable displacement pumps, and was found to lead to lower power consumption and higher operating speeds.

DOI: 10.1007/BFb0035209

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Cite this paper

@inproceedings{Lawrence1995CoordinatedAF, title={Coordinated and Force-Feedback Control of Hydraulic Excavators}, author={Peter D. Lawrence and Septimiu E. Salcudean and Nariman Sepehri and D. Chan and Simon Bachmann and N. Parker and Ming Zhu and R. Frenette}, booktitle={ISER}, year={1995} }