Research On Bilateral Teleoperation Of Flexible Robotic Based On Switching Control Strategy

In recent years,with the deepening of the research on flexible robotic arm,it has been widely used in telemedicine,nuclear industry,aerospace and other fields.In this field,teleoperation technology will be introduced in order to reduce the damage to human beings caused by unknown dangerous environment and the current design of fully autonomous robots has certain deficiencies.Teleoperation technology can integrate human intelligent decision into robot cooperative control,so as to complete the man-machine cooperative form of remote control task.Due to the flexibility of the flexible manipulator itself and the unpredictability of the teleoperation system environment of the flexible manipulator,the system instability and reduced transparency will be caused when the teleoperation method is adopted to control the flexible manipulator.Therefore,in this context,the relevant analysis and research are carried out to solve the problems caused by environmental changes in the teleoperation system.In order to solve these problems,a bilateral teleoperation system of flexible manipulator based on switching control strategy is designed in this dissertation.First,the overall architecture of the teleoperation system of the flexible manipulator is designed,and the dynamics modeling of the master robot and slave robot is carried out respectively.Secondly,according to the passive theory,the active analysis of the environment end of the teleoperation system is carried out.It is concluded that the change of the environmental stiffness will cause the active overflow problem of the environment end,which will affect the stability and transparency of the teleoperation system.To solve this problem,this dissertation proposes an estimation algorithm of the interaction model between the flexible manipulator and the environment.In order to improve the accuracy of the estimation of the environmental stiffness,the flexibility of the joints in the flexible manipulator is analyzed first,and then a stiffness estimator which can accurately estimate the environmental stiffness in real time is designed.Then,according to the contact characteristics between the manipulator and different environments,the teleoperation system is divided into three different modes according to the environmental stiffness during the task,which are free motion mode,flexible contact mode and rigid contact mode.Then,the controllers of the system in these three modes are designed respectively,so as to ensure the stability and transparency of the teleoperation system,and a switching strategy can be designed to dynamically switch control modes according to the transformation of the environment.The range of control law parameters is determined by Lyapunov function,thus ensuring the global stability of the system.Finally,the Geomagic Touch force feedback device and the UR3 e flexible manipulator were used to set up the physical experiment platform of the teleoperation system,which was used to verify the effectiveness of the teleoperation control method based on the handover control strategy proposed in this dissertation.A series of experiments of contact between the remote operating system and the environment are designed according to the different environmental stiffness of the slave end,and the control method proposed in this dissertation is compared with the traditional teleoperation control method.Experimental results show that the proposed control method can ensure the stability and transparency of the teleoperation system when the environmental stiffness changes.