Research On Micro-assembly System Control Technology

With the development of precision manufacturing technology, a large number of micro-electromechanical products gradually develop toward volume miniaturized and functional integrated, and the assembly parts’ size range from only a few hundred micrometers to more than ten millimeters. According to the needs of the actual situation, MEMS products has gradually penetrated into all the fields. For example: Aerospace, bio pharmaceutical, automobile industry, environment monitoring and so on. At present, the majority of MEMS products still rely on manual methods to achieve assembly task all over the world, which is needed for more skilled workers to operate to complete its assembly under the microscope. This kind of manual operation is not only the great intensity of labor, but also the consistency and stability of product assembly cannot be guaranteed.For actual industrial assembly application, In terms of the existing problem in manual assembly about the plate type of miniature parts, design a set of micro parts assembly system based on the type of machine vision and vacuum adsorption, greatly improve the product assembly’s applicability and integration. The whole assembly system is designed with the idea of modular, which is made up of vision identification module, clamping operation module, adjustment of parts attitude module, the human-computer interaction control module.This paper takes the sub-millimeter level of the micro-assembly system as the research object, uses the micro vision servo control technology. Study on the structure characteristics of the stereo microscopic vision as well as the recognition and positioning of the target parts under the environment of the micro-assembly system. Using the micro limit switch settable force feedback control mechanism to control the direction of the Z-axis mode, the Z-axis direction of the assembly to achieve real-time detection and Z-axis force is automatically stopped.Calibration of machine vision system is the foundation to realize the automatic micro-assembly system, this paper presents a reasonable calibration algorithm of visual system, build the hardware model of camera and assembly system. Via the camera calibration, to achieve the conversion between the coordinates of the micro-assembly system, correct the lens distortion, get the satifactory measurement accuracy and the effect of 3D reconstruction.The assembly experiments show that the micro parts of automatic assembly which can be realized in this paper which is proposed by the automatic assembly process and strategy of assembly control system, it can meet the assembly precision and improve the consistency of the product.