Experimental evaluation of bilateral control schemes applied to hydraulic actuators: A comparative study

In this paper, we present experimental results of implementing five bilateral control schemes, widely used for electro-mechanical systems, to a hydraulic actuator. The goal is to investigate the applicability of each control scheme to a hydraulic actuator and compare their performances on a common system. The considered schemes are 'force reflection', 'position error', 'shared compliant control', 'force reflection with passivity' and 'four channels architecture' schemes. The evaluation is conducted in terms of position tracking, force tracking, and fidelity of perceived stiffness by the operator. It is shown that force reflection and four channels architecture control schemes perform best in terms of both position tracking and force tracking during interaction with an environment emulated by different springs. Position error scheme, on the other hand, exhibits good position tracking capability, but cannot track environmental force encountered at the master site. It, however, produces a feel to the operator, based on position error between the slave and the master arms, which is potentially desirable during unconstrained motion control of the actuator.