Disturbance Rejection Control Of Bilateral Teleoperations With Time Varying Delay

Reflected in adaptability to unknown environment and flexibility of operation,teleoperation systems have great advantages in dealing with tasks in remote dangerous environment.Thus the teleoperation systems have great theoretical significance in improving abilities of post disaster rescue and unknown space exploration.With the development of network technology,the teleoperation systems have been more convenient to realize.However,not only manipulators at both sides at the master and slave have strong nonlinearities but also the remote actuator is affected by internal and external disturbances.Therefore,it is difficult to obtain an accurate model to obtain great control performance.In addition,time-delays make the information transmissions between a master side and a slave side delay,which seriously affects synchronization performance of the teleoperation systems.Disturbance rejection controllers will be designed by a relatively accurate nonlinear model so as to improve stability of the teleoperation systems,which is main researches of this paper.Main work is given as follows:The tracking control problem of bilateral teleoperation system with unmeasurable force information and time-varying delay is studied.In order to obtain better transparency,the unmeasurable force information is obtained by designing a nonlinear state observer.An adaptive control law based on the force feedback is designed by a four channel wave variable method to ensure passivity of the bilateral teleoperation systems.The effectiveness of the force observer is analysed via contingent cone criteria and self-stability regions.Moreover,sufficient conditions for stability are given by a Lyapunov-Krasovskii function.Finally,simulation results show that the proposed control law has good anti-interference ability under time-varying delays.A tracking control scheme is investigated for the bilateral teleoperation systems with time-varying delays and dynamic uncertainties.The tracking control scheme is based on an extended state observer,a time-delay part observer and a continuous terminal sliding mode control strategy.The dynamic uncertainties are dealt with by the extended state observer for the bilateral teleoperation system.The time-varying delays withunmeasurable derivatives are estimated by the time-delay part observers.The continuous terminal sliding mode control strategy is used to ensure finite-time convergence for the bilateral teleoperation system without knowing the second derivatives of tracking errors.Finally,experiment results are shown for the bilateral teleoperation system to demonstrate effectiveness of the developed tracking control scheme.A synchronization control problem is investigated for the bilateral teleoperation systems with dynamic uncertainties and random delays.Reduced-order extended state observers,which make calculations of gain matrices be easier than full-order extended state observers,are proposed to estimate the dynamic uncertainties and unmeasurable joint velocities.The model of the bilateral teleoperation systems with random time delay is established by continuous time Markov process.A tracking control strategy based on the reduced order extended state observers is proposed to ensure stability of the closed-loop system.The synchronization performance of the closed-loop bilateral teleoperation systems is proved by the Markov infinitesimal operator.Lastly,experiment results are shown for the bilateral teleoperation system to verify effectiveness of the developed techniques.