Research On Force-Position Hybrid Control Of Bilateral Teleoperation Robot System Induced By Network Delay

Teleoperation robot system is a complex high-precision remote robot control system that can be realized under human control.Among them,stability and transparency are two key issues in the high performance of the teleoperation system.On the one hand,the time delay of long-distance information transmission will affect the stability of the system.On the other hand,force information is the key to measure whether a teleoperation system is excellent.In addition,in practical applications,due to the complexity and uncertainty of the external environment,the control accuracy and reaction speed of the system also have higher requirements.Therefore,it is necessary to study the force-position hybrid control of teleoperation induced by network delay.The main research contents of this paper are as follows :(1)A new force-position hybrid control strategy is proposed for a class of uncertain bilateral teleoperation robot systems with time-varying communication delays.The characteristic of this control method is that it can replace the use of force sensor and relax the assumption of external force.In particular,the proposed terminal sliding mode force observer effectively improves the rapidity of other force observers by introducing variable exponential coefficients to estimate human and environmental forces.By embedding the estimated force information,a force-position hybrid controller is designed to ensure the transparency and stability of the system.In addition,by selecting the LyapunovKrasovskii function to calculate the maximum allowable transmission delay under the given controller parameters,the stability of the bilateral teleoperation robot system under specific linear matrix inequality(LMI)conditions is proved and the system conservatism is reduced.Finally,the experimental simulation results show that the proposed forceposition hybrid controller has superior performance under different external forces.(2)A fixed-time sliding mode control scheme is proposed for teleoperation robot systems with time-varying delay and uncertainty.The transparency of the system is improved under the premise of position tracking and force feedback.Firstly,a masterslave dynamic model based on radial basis function(RBF)neural network is established to effectively estimate uncertainties and external disturbances.Then a fixed-time force observer is designed to accurately estimate the human and external environmental forces.Using the idea of impedance control,the main control end uses the trajectory generator to generate the target tracking trajectory.The slave uses the delay signal transmitted by the master to generate the desired trajectory by the trajectory generator.The updated data is used to design a new controller that can control the system in a fixed time.Finally,the superiority of the controller scheme is illustrated by experimental simulation.