Passive bilateral control of a teleoperation system considering hysteresis nonlinearity of slave robot

The slave robot of the macro-micro teleoperation system presented in this paper is a 1-DOF piezo actuator including hysteresis nonlinearity. This nonlinear behavior makes robot control a complex task. In this research the nonlinear and uncertain dynamics of the slave robot has been entered directly into the teleoperation control loop. The LuGre friction model is used as the estimator of the hysteresis loop to cancel out this undesirable term. A 2-DOF master-slave system is decomposed into two 1-DOF systems: a shape system representing the master-slave position coordination, and a locked system representing the dynamics of the coordinated system. For making the closed-loop teleoperation system passive against dynamic parameter uncertainty and force measurement inaccuracy, four virtual flywheels are designed. In this way, the energy generated by troublesome terms inside controllers (i.e. the terms which may endanger passivity of the controller) would be taken from the bounded kinetic energy deposited on these flywheels. Simulations are performed to show effectiveness of the proposed controllers.