Research On Grinding Surface Waviness Measurement Methods Based On Machine Vision

Surface waviness is an important index and parameter used to assess and measure the parts surface quality,which is the surface geometric irregularity between the micro roughness and macro shape error.Surface waviness is closely related to the mechanical properties of the parts such as contact stiffness,fatigue strength,abrasive resistance,etc.and has significant impact on the service performance and service life of equipment and instrument.Therefore,accurate and efficient measurement of parts surface waviness has a very important engineering application value.Along with the rapid development of science and technology,the demands for the parts surface quality of modern industry is getting higher and higher,the traditional waviness measurement methods have been unable to meet the actual demand of the automated on-line measurement of industrial production because of its low efficiency and poor accuracy.Therefore,exploring a kind of waviness measurement method which is non-contact,high efficiency and high precision has become a research focus for many scholars at home and abroad.Detection method based on machine vision has been applied to the measurement of surface waviness by many researchers because of the advantages of simple measurement method,high precision,wide measuring range,high efficiency and non-contact measurement.Aiming at the current waviness measurement method based on machine vision has the problem of the expensive detection equipment,the complex detection process,the low measurement precision and the low measurement efficiency,The thesis has researched on the mechanism and method of grinding surface waviness measurement based on machine vision,developed a prototype of the measurement system,and evaluated the performance of the system quantitatively,verified the validity of the proposed method and the measurement.The main research contents of this thesis are as follows:(1)Aiming at the surface characteristics of the grinding surface,reaching the definition and evaluation criteria of the surface waviness,describing the imaging mechanism of the grinding surface in detail,analyzing the influence of the waviness size on the image quality of the surface,and selecting the hardware equipment of the grinding surface waviness measurement system prototype development.(2)Aiming at the current waviness measurement method based on machine vision has the problem of the expensive detection equipment,the complex detection process,the low measurement precision and the low measurement efficiency,a method of surface waviness measurement based on full reference image quality assessment has been proposed.The influence of ground surface waviness on image resolution has been analyzed from the mechanism points,it is found that there are some differences between quality of the reflection images formed by the ground surface with different waviness level,Therefore,image sharpness evaluation model can be applied to measure the surface waviness.The experiment result shows that,the method has high detection accuracy for grinding surface waviness measurement,high robustness to light source brightness,and great potential for engineering application?(3)Aiming at the problem that the absolutely clear image of the sample to be evaluated can't be obtained in the field of engineering,proposing a method of surface waviness measurement based on no reference image quality assessment.According to the different blur degree of reflection image of the red and green light source in ground surface with different waviness level,the method has proposed the index of image blur to measure the surface waviness.Compared with waviness measurement method based on the full reference image quality assessment,it is verified that the method has higher accuracy for the measurement of grinding surface waviness.(4)From the perspective of the prototype development of grinding surface waviness measurement based on machine vision,based on the organic combination of LabVIEW and MATLAB,designing and realizing the development of the surface measurement system for grinding surface waviness based on machine vision,then evaluating the accuracy,repeatability and response speed of the detection system.The evaluation results show that,the measurement system has the characteristics of high accuracy,good repeatability and fast response.The research work has a certain theoretical significance and engineering application value for the on-line quality inspection and quality control of precision parts.