Design Of A Precision Assembly System Based On Virtual Prototype Technology

Nowdays, precision assembly is usually done manually. Because manual assembly has some disadvantages such as low percent of pass, poor consistency and high labor intensity, this paper developed a precision assembly system used to assemble rings. At present, the development of automatic precision assembly systems usually applies the traditionally sequential way, in which mechanical design, electrical design and control design run serially. Because the control design is the end of the design, control engineers have to design the control system based on the established mechanical structure, and sometimes they have to modify the mechanical structure to achieve the optimal control design. A precision assembly system for ring assembly was developed by virtual prototype technology to avoid the above situations.The function and precision of the precision assembly system were analyzed. In SolidWorks, driving motors were added into the mechanical model of the system by Motion model forming the mechanical movement model. The control program of the virtual prototype was written by "SoftMotion" model, and the control system was divided into four modules including system debugging, system settings, assembling work and removing work based on the system function. After building the mechanical movement model and the control system of the precision assembly system, the operation of the precision assembly system was simulated by joint simulation technology of Lab VIEW and SolidWorks. In the simulation, the mechanical model of the virtual prototype run based on operation of the control program. In the simulation, the operation of the control software could be simulated, and the running of the mechanical system could be observed and system interference could be detected. The mechanical design and control design were optimized based on the simulation, and the optimized design could be reused in the real physical prototype.A physical prototype of the precision assembly system was set up based on the virtual prototype to realize the automatic assembly of rings. Firstly, mechanical structure was set up based on the mechanical model of the virtual prototype, and suitable mechanical elements were chosen based on the system accuracy. Secondly, computer controller was set up based on the requirements of the system to connect mechanical structure and control program. The key part of the computer controller is a industrial personal computer, and the connection parts are motion control card, data acquisition card and relay control card. Thirdly, the control program of virtual prototype was tranfered into the physical prototype using program packaging technology. In addition, data acquisition and relay control functions were added based on the requirements of the system. Finally, the constructed physical prototype was debugged, and experiments of assembling rings were carried out. The results show that the precise assembly system developed by virtual prototype technology meets the assembly requirements.The whole developing process showed that the virtual prototyping technology could speed up risk-free conversion of virtual prototype to physical prototype, and it shortens the design cycle and reduces design risk.