Research On The Vision System And Calibration Technology Of Modular Placement Machine

Chip mounter is a complex mechanical and electrical system which involves many subjects such as robot,machine vision,computer control,movement control and so on.Among them the vision system and calibration technology are the core technology of chip mounter.This paper introduces the scheme design of the vision system of chip mounter,and respectively discusses the influences on the errors of the accuracy of chip mounter.Through related experiments and data analysis,we can make the accuracy of chip mounter meet the requirements of modern electronic.The article includes following contents:Firstly,by analying the structure and process flow of module chip mounter,the visual system's properties is determined.On this basis,we make the overall design of chip mounter vision system,and determine the constitute of the hardware system.The software part of the vision system,the function modules and the software platform are discussed.Then,the errors of the vision system and the assembly errors of the mechanical manufacturing and the other errors are discussed.The imaging model and lens distortion of the moving camera and stable camera are analyzed.The implication of pixel equivalen and the influence of accuracy are discussed.A careful analysis is made on the error of the parts of the frame and the parts of mounting heads.Other kinds of errors which influnce the accuracy of chip mounter are all analysisedThirdly,we put forward the calibration method of chip mounter.We define the calibration coordinate system used in the calibration.The methods of static calibration and auto calibration for different targets are established.The process of auto calibration is introduced in detail.The principle and method of each auto calibration module are discussed in detail.Finally,the error model of the suction nozzle mounting shafts and the suction nozzle is verified through a series of experiments.And we also verify the correctness of the suction nozzle calibration method.In addition,the positioning accuracy of kinematic axis X and Y of chip mounter is analyzed,and the ideal mounting accuracy is obtained.