Passive Bilateral Control of a Teleoperation System Considering Hysteresis Nonlinearity of Slave Robot

Abstract

Abstract. 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.

Synchronous Control of 2-D.O.F Master-Slave Manipulators Using Actuators With Asymmetric Nonlinear Dead-Zone Characteristics

“…In particular, approaches such as PD/PID control, robust/adaptive control, adaptive neural networks, and combined solutions with the concept of energy passivity have been considered to solve this problem. Early but still pioneering and valuable works using an observer-controller scheme, passive decomposition, a force symmetry bilateral control strategy and, an impedance identifier are presented in [1][2][3][4][5][6][7][8][9]. [1] presented experimental results for master-slave synchronization of two robotic manipulators based on the observer-controller scheme.…”

“…[2] proposed the hydraulic servo 6-DOF master-slave Stewart platform and presented the so-called force symmetry bilateral servo control strategy that improves the response rate and tele-presence of the master-slave control system. [3] explored the slave robot of the macro-micro tele-operation system including 1-DOF piezo actuator with hysteresis nonlinearity. Here, the LuGre friction model is employed to estimate the hysteresis loop and passive decomposition has been applied to design the control system.…”

“…Here, the load force and impedance identifiers are used for identifying the load force and impedance of the slave actuator respectively. Furthermore, even though early works [1][2][3][4][5][6][7][8][9] successfully guarantees the performance of master-slave operation, to strengthen the robustness and adaptability of between teleoperating systems and human operators, several works [10][11][12][13][14][15][16][17] adopt more advanced control methods such as the sliding mode control approaches and adaptive techniques together with fuzzy technique. [10] proposed a control strategy based on sliding mode control for master-slave manipulator control system.…”

“…Furthermore, it shows that the difference between the state of the neural identifier and the reference trajectory converges exponentially to zero. Although the various control strategies [1][2][3][4][5][6][7][8][9][10][13][14][15][17][18][19][20] of a master-slave manipulator have been developed for many applications so far, the studies of synchronous control for higher DOF nonlinear master-slave manipulator systems incorporating actuators with nonlinear dead-zone characteristics have been limited and several existing results are complicate to be implemented in industrial application. In addition, even though the recent approaches based on the adaptive neural networks [17][18][19][20] are promising for masterslave system with dead-zone effect, those are still challenging to be applied to the cost-effective commercial manipulator due to the limitation of micro-controller.…”