Research On Multi-Parameter Detection Technology Of Piston Based On Laser Sensor

Problems such as piston size,shape and surface defects will cause abnormal engine operation,which will result in quality reduction of the car,and threat to personal safety.As a key step in the production of pistons,quality inspection and the accuracy will determine the quality of the pistons,which consequently affect the manufacturing process of automobile.Among all the piston shape parameter detection methods at present,the contact detection method is frequently-used,but there are many defects for this method,for example: low detection accuracy and slow efficiency,easily cause secondary scratches on the surface of the piston,the detection head needs to be replaced regularly,batch inspection for industrial manufacture can not be realized,important parameters such as angle,width,depth and runout of circular groove can not be realized.The principle of the piston detection system studied in this paper was to irradiate the piston surface vertically with a parallel beam,forming a projection image of the piston on the sensor receiving light plate.By specifying the detection position,the key geometric feature of the piston were detected.Based on that,an automatic testing equipment was designed to achieve high precision,high efficiency and non-contact testing.Also,a scanning method for the three-dimensional shape of circular groove was explored,based on the principle of laser triangulation distance measurement,which directly displayed the key feature of the piston circular groove.First,based on the principle of parallel beam projection,a piston circular groove detection platform was built,and hardware and software functional modules were designed accordingly.The motion control system was realized by the hardware based on the motion control card,and MFC was used to program the operation interface.Angle,width,depth and runout of circular groove were displayed by images under the cooperative work of the hardware and software.Second,the optimal test conditions were selected through the data filter window comparison experiment.The data collection method for the parameters mentioned above was determined by setting conditions such as beam and filtering windows,and MATLAB was used for data processing and analysis.After that,a comparative experiment for good and defective pistons was carried out.Third,based on the final piston detection experiment results,the range analysis and the Bessel method were used to carry out uncertainty analysis to further demonstrate the feasibility of the detection systemAt last,a scanning method for the three-dimensional shape of circular groove based on inspection results and laser triangulation distance measurement was raised to directly display the image of the circular groove and carry out demonstrate for good and defective pistons.