Automatic Precise Assembly System For Miniature Flexible Parts

When miniature parts assembled, the large size span of the parts to be installed is not easy to operate, and the assembling process is complex with a high precision of assembly. At present, a lot of miniature parts assembly in micro-electro-mechanical products relies on manual operation with the help of microscope, which results in low work efficiency and poor stability of product quality. Compared with general miniature parts, the flexible structure of miniature flexible parts are prone to have plastic deformation when force is exerted on it. Therefore, its assembly operation is more complex and protective measures should be taken during the operation. The lock fixation of assembly is easy to cause parts’disturbance which is damage to assembling accuracy. Such problems all impact on assembly precision of miniature flexible parts. Therefore, they are all urgent problems to be solved in miniature flexible parts precision assembly.Precision assembly system of miniature flexible parts is composed of visual detection module, assembly operation module, table module and the human-machine interactive control module. Precision assembly system use machine vision as a means of measurement to guide the automated precision assembly with the machine vision measurements. As a means of non-contact measurement, the measurement of machine vision technology will not cause damage to the tested parts with a high accuracy and it can complete the measuring and positioning of micron sized parts.As a key technology in precision assembly, micro manipulation technology designs a combined adsorption clamp unit for the situation—it is difficult to use the same operating tools due to the large size span of miniature flexible parts and obvious differences between the properties of parts. According to the differences between characteristics of the operated objects, the clamp units choose to use the corresponding transition adsorbing block to achieve the adsorption, handling and assembly operations of some micro parts with different structures. Combined clamp unit can expand the range of precision assembly system operation object and improve the availability of precision micro assembly equipment.Assembly system firstly uses " look-move" visually guided control mode and then on to the next specific assembly operation according to the visual inspection results. Machine vision uses "active collection+passive collection " dual camera configuration to achieve the multi-faceted information measurement of complicated flexible parts. Integration of operation mechanical armhas a micro force sensor with high accuracy, which can timely collect assembly contact force, protect the fragile structure of flexible parts and achieve the control of micro assembly force. Set up the assembly coordinate system model to calculate mathematical model and realize the transformation between multi coordinate systems. Based on OpenCV, image processing techniques realize the plural handle to parts image, extract edge information of parts. Finally, get pose information of measured parts using the appropriate positioning method.Under the laboratory conditions, assembly experiment to miniature flexible parts precise assembly system developed are carried out. The experimental results show that miniature flexible parts precise assembly system can complete the assembly in accordance with assembly requirements, and the assembly accuracy can meet the requirements.