Stability Analysis Of Bilateral Teleoperation System With Time-varying Delay

Bilateral teleoperation system is widely used in aerospace,telemedicine,and power systems,and have played an important role in breaking the limits of human control space.Because the operator in the teleoperation system is far away from the environment,there is a network communication delay in the transmission of information,resulting in the inability to interact in time with the force and position of the two ends of the system,which will seriously deteriorate the stability of the teleoperation system and reduce the control performance of the system.Relevant scholars have carried out a lot of research on the problem of the delay of the teleoperation system,but the existing methods are still difficult to effectively reduce the impact of the delay on the system.This paper studies the time-varying delay problem,and will establish a time-varying delay teleoperation system control method based on position prediction and force prediction,which can effectively solve the problem of system stability and improve system control performance.The main work of this article is as follows:(1)Investigate the application scenarios,technical development and control methods of the teleoperation system,study the impact of objectively existing communication delay on system stability and transparency,and clarify the research focus of the application of teleoperation technology.Combining the investigation and analysis results,a predictive control method based on four-channel control structure is proposed.(2)The two-port network equivalent model of the bilateral teleoperation system is studied,the transparency analysis index is given,the transparency performance of the four teleoperation control structures is compared and analyzed,and the two stability analysis methods are compared and analyzed.Based on the analysis results,a predictive control method based on a four-channel control structure is proposed.The predictive control module is added at the master side to predict the force and position information of the slave robot.The absolute stability analysis method is used to give the stability boundary conditions of the teleoperation predictive control system proposed in this paper.(3)Aiming at the problem of position signal delay of bilateral teleoperation system,the position prediction method is studied.The master will obtain the position signal of the slave with time delay,so the Kalman filter(KLF)method is used to predict the position signal.Considering the nature of the discreteness of the KLF filtering process,the concrete method and process of the discrete system equivalent continuous system are given.The simulation method is used to verify the proposed method.(4)Aiming at the problem of the time lag of force signals in bilateral teleoperation systems,the contact force prediction method is studied.A contact force prediction model based on the Hunt-Crossley model is established on the master side to obtain the contact force signal of the slave robot without delay.The characterization methods of several contact force models are introduced,the application characteristics of the models are discussed,and several basic requirements for the selection of contact force models are given.Using recursive least squares based on genetic factors to quickly identify environmental parameters,implement a modified master-end predictive force model.The simulation method is used to verify the proposed method.(5)For the proposed teleoperation control system based on force and position prediction,the system stability and handling performance are analyzed.The absolute stability theorem is used to analyze the system stability,and the system stability boundary conditions are given.Build a simulation platform to realize the function,connection and communication of each module of the teleoperation system,and use simulation experiments to verify the proposed method.