The Predictive Simulation Technology Research On Contact Force At The End Of The Space Manipulator Teleoperation

The space manipulator teleoperation technology introduces human intelligence into the closed loop of the manipulator control system,which greatly improves the intelligence of the manipulator and its adaptability to complex tasks.NASA states that 50%of in-orbit and planetary surface work will be achieved through space manipulator teleoperation technology in future.In space manipulator teleoperation tasks,ground operators’perception of the operating environment is particularly important.Visual and force perception are the main ways of human to perceive the environment,and force perception accounts for more than 70%of the total perception in contact operation tasks.The teleoperated system requires strict real-time and stability of contact force feedback from the slave,but due to the distance between the space manipulator and the ground operator,it is difficult for the contact force from the slave to be fed back to the master in a real-time and stable manner.Real-time prediction of the slave contact force can effectively improve the stability of the teleoperation system and the operating experience of the ground operator.Therefore,it is important to carry out the research on prediction and simulation technology of the contact force at the end of space manipulator teleoperation.This paper carry out the research on the prediction and simulation technology of the contact force at the end of space manipulator teleoperation.Specifically,it includes master-slave heterogeneous teleoperation system motion matching method,slave-end manipulator rigid contact prediction,slave-end manipulator flexible contact force prediction,space manipulator teleoperation system motion matching and contact force prediction method verification experiment.Firstly,the research of the master-slave heterogeneous teleoperation system motion matching method is carried out.To address the heterogeneity of the master-slave manipulator in the teleoperation system,which makes it difficult to guarantee the operation accuracy and operation experience at the same time,this paper establishes a kinematic model of the master-slave robotic arm and analyzes the master-slave differences from multiple perspectives of position space,velocity space and force space;designs an adaptive velocity-level incremental mapping method based on the closest distance,which significantly reduces the reset times of the master manipulator without losing the operation accuracy.Secondly,a study on the prediction of rigid contact of the slave-end manipulator is carried out.To address the modeling error of the virtual scene at the master and the inherent positioning error of the manipulator itself,which makes it difficult to predict the rigid contact force,this paper establishes a slave environment model with the characteristics of both voxel and point-shell models,and builds a point cloud model of the end of the manipulator.A collision detection and distance calculation method is designed between the static and dynamic models at the slave,and proposes a feedback force calculation method based on the pre-contact force to compensate for the position error on the feedback force calculation method based on pre-contact force is proposed to compensate for the influence of position error on the prediction of rigid contact force,and enhance the role of feedback information of rigid contact force in virtual environment to assist operators.Again,the research of flexible contact force prediction from the end of the manipulator is carried out.For the problem of high complexity of flexible contact force model and calculation,this paper analyzes the physical properties of the flexible body in the working environment of the space manipulator and establishes the flexible body physical property expression model;adds virtual springs to the simple spring mass surface model and establishes the flexible body physical model,which reduces the model complexity by tens of times with the same accuracy;designs the collision detection method under GPU and establishes the feedback force calculation model,based on the The least squares method is carried out to identify the environmental dynamics parameters and complete the flexible contact force prediction from the end.Finally,the physical experiment platform of the manipulator teleoperation system is built and the corresponding software control platform is designed to carry out the experiments of motion matching and contact force prediction by the teleoperation system to verify the feasibility of the motion matching and rigid contact prediction methods designed in this paper;the real-time contact force between the end of the manipulator and the flexible body is measured and compared with the predicted simulation force to prove the effectiveness of the contact force prediction method of the flexible body at the end of the robotic arm from the end of this paper.The effectiveness of the prediction method is demonstrated.To sum up,this paper has carried out in-depth research on the key problems existing in the prediction and simulation technology of contact force at the end of remote operation of space manipulator,and has achieved certain research results,which provides a theoretical basis for the establishment of remote operation system of control manipulator.