Development Of Machining Error Detection Equipment For Heavy Truck Axle Housing Based On Machine Vision

For complex parts,the traditional measurement method mostly uses the contact coordinate measuring machine(CMM),which has the advantages of high measurement accuracy and many measurement features,and is very suitable for measurement of small and medium-sized complex parts.However,it takes a long time and labor intensive to measure large size and Complex parts,and has the shortcomings of not realizing on-line measurement are also highlighted.With the need of industrial automation,the measurement of dimension and form and position error of complex parts has been paid more attention.It directly or indirectly affects the quality of products and is an important factor restricting the development of high-end manufacturing industry.In recent years,benefit from the rapid development of machine vision,optical technology and image processing,machine vision has been applied in the field of industrial inspection,however,there are relatively few visual inspection instrument,which still incapable meet the requirements of enterprise automation and flexible production.Therefore,the field of visual inspection has great development space and broad market prospects.This paper is based on the project of "Research on Heavy Truck Axle Housing Flexible Manufacturing Technology and Production Line Construction",which is to develop a vision-based detection equipment for machining errors of heavy truck axle housing.Previously,in the heavy truck axle housing processing production line,the detection process mostly used dialgage,template comparison,CMM and so on.These detection methods are inefficient,error-prone and difficult to store test results,which can not meet the needs of large-scale and automated production.Therefore,there is an urgent need to develop an automatic testing equipment which can be applied to the flexible manufacturing technology of axle housing.Based on the current situation of the enterprise,this paper starts from the reality and carries out the following research:According to the size and structural characteristics of the MCY13 series heavy-duty axle housing,an intelligent detection equipment for the series of heavy-duty axle housings is designed.The equipment consists of mechanical system,control system and vision system.The mechanical system mainly provides the hardware foundation for the control and vision system and realizes the automaticpositioning and alignment of the 6 degrees of freedom of the heavy axle housing.The control system has high intelligence,good human-computer interaction interface and safety protection measures(limit alarm,pressure alarm,travel alarm,etc.).The vision system uses three industrial cameras to enable simultaneous measurement of multiple machining errors to meet the processing cycle requirements of the production line.Aiming at the processing error measurement of heavy-duty axle housing,this paper proposes a visual measurement method for large-axis diameter,coaxiality,Runout and Position of circumferentially distributed holes.Among them,the large-diameter size visual measurement method can effectively improve the measurement accuracy of the axle diameter of the heavy-duty axle housing by improving the pixel equivalent calibration.Coaxiality and runout error measurement is realized by algorithm optimization,the principle is consistent with the definition of national standard,and the calculation is simple and accurate.The positional measurement of the circumferential distribution holes are constructed by coordinate transformation to construct the positional relationship of the circumferential distribution holes,which avoids image splicing,and the calculation amount is small and high precision can be obtained.At the end of the paper,through the test of the detection equipment the results show that the visual measurement equipment has relative stability,the size fluctuates within a small range,and there is a certain system randomness error,but the overall result can reflect the real situation of the processing error of the axle housing.Can replace some traditional testing procedures.