Design And Implementation Of Virtual Assembly And Disassembly Training Generative System

The assembly and disassembly of mechanical equipment is an important process in the manufacturing industry,and there is a great demand for skilled personnel.Virtual reality technology can effectively reduce the training cost,avoid the occurrence of training risks,and achieve a good training effect.However,in enterprises’ actual production,there are a large number of assembly and disassembly tasks.It is needed to develop a corresponding VR training program for each task,and in many cases it is needed to develop several VR training modes for each task such as demonstrate mode and practice mode.Customized development way for each task and each mode one by one will require a very long development cycle and cost the enterprises a lot.To sovle this problem,a virtual assembly and disassembly training generative system was proposed to help enterprises to delveop VR assembly and disassembly training programs conveniently and efficiently in a visual way,so the cost of virtual assembly and disassembly skill training can be reduced and the efficiency of enterprises can be improved.The main work of this article is as follows:(1)A XML based parameterized presenting method of assembly and disassembly operations is proposed.This method firstly extracts the common features of assembly and disassembly operations,divides them into several geometric motions,and presents a assembly and disassembly operation process with unified parameters.Finally,these parameters are stored as data files in XML format.The framework of the system is designed with the data file as the core.The system contains a visual editor to edit the model and data file of the disassembly task.By downloading the model and data file of a assembly and disassembly task into the virtual assembly and disassembly training platform,the virtual assembly and disassembly training of the task can be carried out.(2)The key algorithms and methods of assembly and disassembly task visual editor were proposed and implemented.Based on the mapping relationship between the screen space and the world space,the method of adjusting pose and position of camera and model is constructed.Based on this method,users can intuitively edit the various models required by the virtual assembly and disassembly task,and based on this method users can edit multiple parameters of an assembly and disassembly operation by directly operating the part model.A 3D A* pathfinding algorithm is proposed and implemented to obtain the moving path parameters of parts,and the obtained path is smoothed by ray detection.The path parameter enables automatic pathfinding of the parts in demonstrate mode of VR assembly and disassembly training environment.A graph meta based visual editing method for assembly and disassembly sequences is proposed and implemented.This method enables users to edit complex assembly and disassembly sequences in a way of “what you see is what yu get”.Using the above key methods,users can edit the model file and data file of an assembly and disassembly task intuitively and conveniently.(3)The key algorithms and methods of virtual assembly and disassembly training platform are proposed and implemented.The DOM technology is used to implement the parsing of XML data file.Lists of parsed data class are used to implement the data presentation method based on assembly and disassembly sequence.An operate-response model for VR assembly and disassembly based on finite state machine and production rules is designed and implemented.Based on this model and collision detection,the interactive function of virtual assembly and disassembly is built,and computing methods of every operation types are implemented by means of graphical calculation.An automatic demonstration method of virtual assembly and disassembly task is proposed and implemented which can be implemented by reading the parameters in the XML data file and combining with the graphical calculation,without the need of making an additional demonstration animation.(4)Combined with the above research,the virtual assembly and disassembly training generative system was designed and implemented.Three modules of the system including the assembly and disassembly task visual editor,the virtual assembly and disassembly training platform and the trainee user system were designed and implemented.