An Adaptive Proportional Plus Damping Control for Teleoperation Systems with Asymmetric Time-Varying Communication Delays

Abstract

Communication delay is an important factor affecting the stability and performance of telerobotic systems. In this paper, a new adaptive proportional damping controller is proposed to improve the stability and performance of the system in the presence of the cases such as asymmetric communication delay, unknown gravity torque, friction torque, and other disturbance torques. The proposed proportional damping control method combines the RBF neural network and adaptive control strategy to compensate for the unknown torque. The stability and robustness of the system are enhanced by adding error-damping items, operator force, and environmental force items. The Lyapunov–Krasovskii functional is employed to analyze and prove the exponential stability and signal boundedness of the closed-loop system. The simulation results verify the correctness of the proposed method, and the comparison with the results of other control methods shows the effectiveness of the designed control strategy.

Robust Adaptive-Sliding-Mode Control for Teleoperation Systems with Time-Varying Delays and Uncertainties

“…In experiments, the time delay is chosen as d(t) = 0.25 + 0.2sin(t) s. The initial states of the master and slave robots are set as q m = q s = 0 0.145 T , and the initial velocities and acceleration are zero. Three types of controllers are adopted for comparison, including the proportional plus damping controller (P + dC) [17,18,45], sliding-mode controller (SC), and the proposed adaptive-sliding-mode controller (ASC).…”

“…In experiments, the time delay is chosen as ( ) = 0.25 + 0 s. The initial states of the master and slave robots are set as = = [ 0 0.14 the initial velocities and acceleration are zero. Three types of controllers are ado comparison, including the proportional plus damping controller (P + dC) [17,18,4 ing-mode controller (SC), and the proposed adaptive-sliding-mode controller (AS following indices are considered for performance comparisons: the integral absolu (IAE), the integral time absolute error (ITAE), the integral square error (ISE), and gral time square error (ITSE) [57].…”

“…Remark 2. The required input torques on the master and slave sides are shown in (17) and (18). The input torques include both equivalent and switching control actions.…”

“…In [17], an event-triggered mechanism combined with a PD-like controller was presented for bilateral teleoperation systems to address communication channel congestion. In [18], an adaptive proportional damping controller utilizing an RBF neural network and adaptive control strategy was proposed to enhance stability and performance in a telerobotic system. On the other hand, timedomain-passivity control is a widely used approach to preserve the stability of teleoperation systems.…”