Contact Control And Error Analysis In Precision Assembly Of Miniature Parts

The assembly of miniature parts with small size and high assembly precision requirement mainly depends on experienced and skilled workers, which increases the working intensity and factitious factors, and greatly influences the quality of products and the efficiency of assembly. Advanced auto assembly technology of miniature parts is important to improving the quality of products, shortening production cycle and reducing cost. A precision assembly system based on machine vision and laser displacement sensor was developed according to the characteristic and assembly precision requirement of miniature parts. The research focused on contact state detection and control during the assembly process of miniature parts.The strategy of precision assembly was determined after analyzing the structural characteristic and assembly precision requirement of the miniature parts. Precise positioning in XY-plane was conducted by machine vision system, while a closed-loop system composed of laser displacement sensor and IPC was introduced to detect and control the contact state in Z-axis.The precision assembly system based on machine vision and laser displacement sensor was established, which mainly consists of operating manipulator module, precision vision detection and distance measurement sensing module, special fixture module, precision adjustment module and human-computer interface module.The theory of error measurement and synthesis was analyzed and researched. According to the hardware parameters of the guide-ways and CCD cameras as well as the strategy of precision assembly, the reasons for assembly errors were analyzed. Assembly errors were calculated based on the theory of random error synthesis according to limit error.