Research On Teleoperation System With Uncertain Large Time Delay Oriented To On-orbit Service

In the exploration of outer space,on-orbit service is carried out through space station or satellite,remote control is used to carry out various tasks as truss assembly,jack task and modular object replacement by remote technology,because of the complexity of the tasks in this process,which not only needs to control the robot accurately and precisely,but also need to understand some unknown environment through the slave robot.At the same time,when the unpredictable situation occurs,it requires human intervention.Bilateral teleoperation control method is an effective man-machine cooperation,the bilateral teleoperation was carried out by design the master and slave arm and communication links into the same control loop.However,due to the time delay,the system will becomes unstable and the tracking accuracy will be poor,and the control system will be difficult to operate.This dissertation studies the poor stability and low trace of the control system under uncertain communication delay conditions.Firstly,two conventional methods are analyzed.The bilateral control based on the position PD algorithm and bilateral control based on direct contact force feedback from the slave environment,both of the two methods are modeled,the analysis of system stability parameters and the analysis of transparency,Based on this,the simulation of Simulink with two algorithms is carried out,and the influence of parameters on the system is analyzed.At the same time,a real experiment is carried out to verify the comprehensive effect under uncertain large time delay.Secondly,according to the passive theory,the time-domain passive algorithm is adopted in the bilateral control,and the passive observer and the passive controller are added to the control system to determine whether the communication link has been in a state of consuming energy in real time.That is the passive state.When the passivity is not satisfied,the system uses the variable damping element in the series controller or the parallel controller to consume the excess energy so that the system can reach the passive state again.According to the different situations of input and output in the master and slave,the series controller is used to correct the feedback force in the master side,and the parallel controller is used in the slave side to modify the receiving speed so that the whole system meets the passive stability.The simulation results show that this algorithm can perform the remote operation under the condition of uncertain large time delay of about 2 seconds,this method have better performance compared with the traditional bilateral control methods.Finally,based on the proposed algorithm,a ground test verification platform is set up,the three-freedom motion controller is used as the master,the Falcon controller is used as the slave to test the effectiveness of the jack task under the proposed method.