| In order to make the robot work effectively in the dangerous and unknown environment,teleoperation technology is an effective means.The time delay is an urgent problem in teleoperation.The space robot is mainly controlled by teleoperation technology.Compared with the ground robot,the space robot is confronted with more difficulties in teleoperation,especially the large time delay problem caused by the longdistance signal transmission between heaven and earth.The large time delay makes the operator unable to obtain real-time feedback information from the remote end,resulting in the operator can not send instructions according to the real-time signal,thus affecting the effective control of the remote devices.Virtual reality technology is an effective way to solve large delay problem.Relying on the research project of mixed reality teleoperation technology for manned lunar exploration,this paper applies virtual reality technology to robot teleoperation control to solve the impact of large time delay.The main research contents are as follows:(1)A mobile robot teleoperation simulation system based on virtual reality technology has been developed.By quickly establishing a 3D environment consistent with the remote end,the robot's trajectory is planned in virtual reality and simulated and verified.Then the verified control instructions are sent to the remote robot for control operation.The method solves the difficulty of autonomous decision-making in complex environment,shortens the decision-making time,improves the control efficiency,and effectively compensates for the large delay in the process of teleoperation control by using analog control similar to the real environment.(2)Under the premise of ensuring the position accuracy of key points,two kinds of3 D fast construction methods of remote environment are realized.To solve the problem of single texture of lunar surface,this paper developed a method of artificial feature point selection for rapid 3D reconstruction.The feature points of obstacles were selected interactively through binocular stereo vision technology,and then the obstacle model was reconstructed according to the 3D coordinate information of the feature points.Aiming at the environment with known standard texture,this paper proposes a fast 3D reconstruction method based on the obstacle model: the main 3D environment model is reconstructed through Metashape,and the obstacle position information is obtained.Then the simplified obstacle model is established in the 3D virtual environment constructed according to the obstacle position information in Unity 3D.(3)A* algorithm based on navigation mesh method is adopted to plan the motion trajectory of the virtual simulation robot.The 3D environment model is divided into navigation mesh,and the A* algorithm is improved to be suitable for the polygon navigation mesh to generate the actual optimal path.Finally,the pathfinding test is carried out in Unity 3D.Experimental results show that the search efficiency of A* algorithm based on navigation mesh is obviously higher than that of A* algorithm based on square map in the present environment.(4)A test platform for teleoperation mobile robot based on virtual reality was built.In this platform,the actual control of mobile robot is integrated with the simulated control in virtual reality environment,and the joint debugging of virtual control and actual control is carried out.During the experiment,the data communication between the two is normal and the system runs smoothly,which can realize the synchronous movement of the real robot and the virtual robot.In the testing process,the 3D environment can be reconstructed quickly,and the reconstruction accuracy is less than 1.5%.The experiment shows that the remote navigation control of the real mobile robot in unknown environment can be realized by planning the trajectory of the virtual simulation robot.. |
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