In-situ Visual Detection And Compensation Of Full Contour Error In Profile Grinding

Curve grinding is commonly applied in the processing of curve parts with complicated contour,such as precision cutting tools and moulds.Error compensation is a relatively effective method to improve the machining accuracy and has been widely used in traditional optical curve grinding.However,the error compensation methods in existence have some problems such as low efficiency,manual dependence and limited compensation effect.Machine vision has the advantages of high efficiency,direct measurement and non-contact features.Therefore,this study focused on researching the machine vision based in-situ detection and compensation of contour errors in profile grinding of large size workpiece.Main work and research results of this paper are as follows:(1)The theory of curve grinding based on machine vision was introduced.The visual measurement system was designed.The in-situ measurement of curve contour was described,including image acquisition,sub-pixel edge extraction and calibration of visual measurement system.The experiment was conducted to verify the accuracy of the in-situ measurement method.(2)A method was proposed to evaluate the overall profile accuracy of the workpiece with irregular contour.The in-situ evaluation of the contour accuracy of the workpiece in the profile grinding was achieved.The experiment was conducted and the results showed that the method can be effectively used for evaluating the contour accuracy of curved parts.(3)A new method was proposed to online detect and compensate errors caused by the grinding wheel wear based on the local mage.The efficiency of the algorithm was optimized.The experiments were conducted and the experimental results indicated that the online error detection and compensation method can effectively detect and compensate the error caused by the grinding wheel wear and improve the machining accuracy of the workpiece.(4)An image stitching method was proposed for stitching the curve contour finished in profile grinding.The stitching precision was evaluated in the designed experiment and the results was verified to meet the profile measuring requirements.A method for detecting and compensating the full contour error of the workpiece was proposed based on the stitched image.The experiment results showed that the proposed method can effectively reduce the machining error in the profile grinding and improve the machining accuracy of the workpiece.