A Lyapunov Stable Controller for Bilateral Haptic Teleoperation of Single-Rod Hydraulic Actuators

Abstract

A Lyapunov stable control scheme is designed and implemented for bilateral haptic teleoperation of a single-rod hydraulic actuator. The proposed controller is capable of reducing position errors at master and slave sides, as well as perceiving the interaction force between the actuator and the task environment without a need for direct measurement of force. The controller only requires the actuator's line pressures and displacements of the master and slave. Stability of the proposed controller incorporating hydraulic nonlinearities and operator dynamics is analytically proven. Simulation studies demonstrate that the proposed system can reach an equilibrium point while interacting with an environment exhibiting stiffness. Experimental results confirm that the controller is able to effectively maintain stability, while having good position tracking by the hydraulic actuator as well as perceiving the contact force between the actuator and the task environment without direct measurement. This kind of haptic feedback force is a suitable choice for applications where mounting a force sensor at the end-effector is not feasible, such as excavators and backhoes. This work contributes to enhancing the operator's ability to perform stable haptic-enabled teleoperation of hydraulic manipulators.