Safe operation for teleoperated robotic manipulators with restricted synchronization error via non-singular terminal sliding-mode control

This study presents the design of a robust controller based on the sliding mode theory to ensure the safe operative synchronization of a teleoperated robotic system (TRS). The TRS is integrated by two fully actuated robotic manipulators (RMs) with n degrees of freedom (DoF). The proposed controller implements a decentralized adaptive super-twisting algorithm to obtain the force applied by the human operator and the environment over the TRS. Then, a decentralized non-singular terminal sliding mode (NTSM) controller solves the synchronization problem for the proposed RMs. The novel control approach ensures synchronization, considering that both manipulators have restricted working spaces. The suggested controller enforces the convergence to the origin for the tracking error in a finite time, at least theoretically. The stability analysis of the proposed controller is developed using the second stability method of Lyapunov, considering a class of barrier Lyapunov controlled function. Finally, simulation results are presented to evidence the effectiveness of both proposed algorithms, the adaptive force estimator and the NTSM.