Fault Tolerant Control of a Teleoperated Piezoelectric Microgripper

This paper presents a new architecture of control for micro-teleoperation system using a fault tolerant control (FTC) strategy to compensate for the degradation effects of piezoelectric-based microgipping system. The proposed strategy uses passivity approach for the bilateral controller and robust fault tolerant control (FTC) for the two-fingered microgripper system. First, the bilateral controller architecture uses the passivity approach for the teleoperation system in the presence of time delay and scaling factor variations. Second, the FTC controller is designed in such a way that the performance and robustness may be done separately which has the potential to overcome the conflict between performance and robustness in the traditional feedback framework. The controller architecture works in such a way that the feedback control system will be solely controlled by the PI performance controller for a nominal model and the robust H∞ controller will only be active in the presence of uncertainties or degradation disturbances. The experimental and simulation results show clearly the effectiveness of the proposed approach against time delays, scaling factors and fault disturbances.