Research On Compliant Control Method For Coordinate Operations Of Space Multi-Arm Robot

With the development of space exploration,the demand for large spacecraft and large space structures is increasing day by day.In order to break through the limitations of the launch vehicle load on the mass and size of the spacecraft,using Multi-Arm Space Robot to assemble and serve spacecraft and space structures on-orbit has gradually become one of the development directions of space technology.In the tasks,the internal forces exist in the coordinated operation system composed of the MultiArm Space Robot and the target load.Losing the control of the internal force will lead to failure of the task and cause great losses.Therefore,when determining the control strategy of Multi-Arm Space Robot,not only the position of the target and manipulators should be considered,but also the internal force in the system should be controlled.This essay takes the Multi-Arm Free-Floating Space Robot as the research object.Aiming at the large target operation tasks,the research on the compliant control method of the Multi-Arm Space Robot is carried out.The dynamic model and the impedance controller of the Multi-Arm Space Robot is established.Moreover,the impedance controller considering the attitude of the base is established.Based on the dynamic model of the coordinated operation system,the compliance controller of Multi-Arm Space Robot considering unknown factors is designed,and the ground verification of the controller is completed.Experiments verify the validity and correctness of the proposed theory.The main research work is as follows:Firstly,the compliant control method of Multi-Arm Space Robot is studied.Establish the kinematics and dynamics model of the Multi-Arm Space Robot,and obtain the mapping relationship between the motion of the end of each manipulator,joint motion and base motion of the MultiArm Space Robot;analyze the motion constraints relationship between Multi-Arm Space Robot and the target in the coordination operation system,and then construct an impedance controller of Multi-Arm Space Robot to achieve simultaneous control of the force and position of the end of each manipulator.Secondly,the compliant control of the Multi-Arm Space Robot considering the attitude of the base is studied.Analyze and coordinate the linear momentum and angular momentum of the coordinated operation system,establish the momentum conservation equation,and complete the decoupling of the joint motion of each manipulator and the base motion;complete the research on the base attitude adjustment method based on the zero-space method and decouple the base motion and operation tasks.The motion of the end of each manipulator of the Multi-Arm Space Robot and the posture of the base are planning coordinatedly;the base posture adjustment method is introduced into the compliance controller of coordinated operation of the Multi-Arm Space Robot to realize the undisturbed compliance control optimization of the base.Afterwards,the research on the compliant control method of MultiArm Space Robot considering unknown factors is carried out.Analyze the force constraint relationship in the coordination operation system,establish the dynamic model of the target,and then complete the dynamic modeling of the coordinated operation system,and obtain the mapping relationship between the target motion and the joint driving force of the Multi-Arm Space Robot and the internal force of the system.The modular compensation term is used to establish a Multi-Arm Space Robot compliant controller that considers unknown factors to reduce the influence of unknown parameters of Multi-Arm Space Robot and the target on the control accuracy.Finally,based on the existing microgravity air flotation experimental platform in the laboratory,the experimental platform is retrofited,including the development of the three-dimensional visualization software of the microgravity air flotation experimental platform,the completion of the configuration of data measurement and acquisition related equipment,and the construction of the dual-arm robot system control platform,etc.;secondly,the design of the free-floating dual-arm robot compliance controller verification experimental scheme,the experiment is carried out and the experimental data is saved;finally,the experimental results are analyzed to verify the effectiveness and correctness of the compliance control method.