Research And Application Of Size Deviation Control Model For Automobile Wheel Production Line

As the demand for automated production lines in the automotive industry increases,there is a growing interest in ensuring consistency in the size of large-scale production and processing of production lines.Due to cost,tempo,etc.,the processing size of the production line parts is more detected by the off-machine inspection.The CNC machine tools and the detection instruments are separated.There is no closed-loop control of the part processing dimensions,which often results in the fact that the part size is out of tolerance.Therefore,how to use the prediction of the dimensional change trend of parts processing,through the interconnection and cooperative control of the CNC machine tools and testing equipment of the production line,to realize the online closed-loop control of the size of the processing parts of the production line,and the quality problem of ensuring the processing size of the parts is also proposed.This paper combines the national science and technology major special project "automated production line control system for automotive key parts processing and industrial robot demonstration application",and systematically and in-depth research on the above issues.This paper proposes a dimensional deviation control model for the production line of automotive wheel hub flange parts.Through the monitoring and prediction of the continuous detection data of the off-board detector,and feedback to the control system of the CNC machine tool in real time,the variation trend of the part size is given.CNC machine tools need to adjust the dimensional compensation value during the machining of parts,so that the dimensional deviation of the machined parts always fluctuates within the tolerance zone,realizing online monitoring and closed-loop control of the processing dimensions of the production line parts.This paper has carried out research work in the following aspects:(1)Taking the automobile wheel hub flange parts production line as the application object,the composition of the production line,the manufacturing process and the method of detecting and collecting the size of the machined parts are introduced.The openness of the CNC system of the production line and the automatic detection of the off-machine detector provide the foundation and guarantee for online control of the dimensions of machined parts.(2)According to the characteristics of machining dimensions of automobile hub flange parts,three dimensional deviation prediction algorithms based on time series-based exponential smoothing method,ARIMA and BP neural network in artificial neural network are used to model the machining dimensions of parts.The simulation experiments were carried out on the 8 types of data of the processing parts of the production line.The data were compared with the prediction algorithm by comparing the root mean square error(RMSE)and the expected absolute error(EVAD)under various prediction algorithms.(3)Using the tool compensation value of CNC system as the tool and means to control the size of the part,the tool compensation evaluation method based on the expectation method and the weighting coefficient method is studied.The specific determination method of each type of data is based on the tolerance of the comparative simulation experiment,which is determined with the centerline root mean square error(SRMSE)and expected value(E)parameters.For the different size tool compensation of the same part,a part processing size control method combining tool compensation values is proposed.(4)Based on the part processing dimension deviation control model and tool compensation evaluation method,the dimensional deviation control software was developed.The software performs tool compensation value correction for every 20 data of each class,which is based on the Huazhong 8 type numerical control system and online detector to realize real-time communication and adjustment of compensation data.(5)Verification and testing were carried out in the actual processing of the automobile hub flange part production line.By comparing and analyzing 20 groups of data before tool compensation and 80 groups of data after tool compensation,it was found that the dimensional deviation data was controlled within the tolerance zone and close to the centerline of the tolerance band,the tolerance for data fluctuation is high,and the expected effect is achieved.Finally,it is concluded that the dimensional deviation control model realizes on-line monitoring and correction of the dimensions of the machined parts,effectively guarantees the quality of the production line parts and improves the processing efficiency of the production line parts.