Type-2 Fuzzy logic based time-delayed shared control in online-switching tele-operated and autonomous systems

This paper develops a novel shared control scheme for online-switching tele-operated and autonomous system with time-varying delays. Type-2 Takagi-Sugeno (T-S) fuzzy model is used to describe the dynamics of master and slave robots in this system. A novel non-singular fast terminal siding mode (NFTSM)-based algorithm combined with an extended wave-based time domain passivity approach (TDPA) is presented to enhance the master-slave motion synchronization in the tele-operated mode and reference-slave motion synchronization in the autonomous mode, while simultaneously ensuring the stability of the overall system in the presence of arbitrary time delays. In addition, based on the Type-2 Fuzzy model, a new torque observer is designed to estimate the external torques and then the torque tracking method is employed in the control laws to let the slave apply the designated force to further improve the operator's force perception for the environment. The stability of the closed-loop system is proven using the Lyapunov-Krasovskii functions. Finally, experiments using two haptic devices prove the superiority of the proposed strategy.