Research On Real-time Detection Of Surface Defects On Automotive Oil Tubes Based On Linear Laser

With the development of the automotive industry,the automotive parts industry chain also needs to be continuously upgraded.Among them,the automotive oil tube,as an important component,is widely used in various systems of automobiles.However,if there are quality problems such as scratches,dents,abrasions,and scars on the surface of the oil tube,it will affect its aesthetics,and more seriously,may cause gasoline leakage.To solve this problem,the author designed a set of online defect detection system for the surface of automotive oil tubes,mainly using the method of linear laser scanning measurement for online detection.In the overall construction of the equipment,the author mainly completed the following tasks:(1)In the process of building the hardware part of the equipment,there are issues such as the external framework design,oil pipe positioning,oil pipe transmission,overall dust prevention of the equipment,and uniform installation of four line laser sensors.To address the above issues,this article designs the overall appearance of the device based on Solid Works software;the author realized the control of the servo motor on the conveyor belt slider,and controlled the slider to move left and right at a fixed speed,simulating the technical requirements of oil tubes moving at a speed of 0.5m/s in actual industrial production;based on the NI acquisition card,the author designed a voltage divider circuit to collect the digital signal of the NPN-type infrared photoelectric switch sensor switch quantity,and designed an optocoupler isolation circuit to enable the acquisition card to control the inkjet printer through pulse signals.(2)Prior to this,there was no complete online monitoring system for oil tube surface defects based on the LabVIEW platform,this article completes the design of the acquisition card control monitoring part,the linear laser sensor data acquisition and processing part,and the data recording and saving part.The acquisition card control monitoring part mainly enables the NI acquisition card to complete the digital signal acquisition of the proximity displacement sensor,combined with the internal clock of the NI acquisition card to obtain indicators such as the number of oil tubes and the speed of oil tubes,and generates pulse signals to complete the online control of the inkjet printer,realizing the marking function of the surface defects of the oil tube;the data acquisition and processing part mainly realizes the collection of the oil tube profile by the linear laser sensor,and filters the collected oil tube profile data with median filtering.Combined with the Gaussian-Newton improved least squares method to fit the data circle and compare it with the original oil tube profile data to extract oil tube surface defect information,and display the defect position on the front panel;the data recording and saving part mainly records and saves the collected oil tube quantity,batch and other status data and defect data.(3)an experimental platform was built to verify the working status and performance of the entire system,and test various application indicators such as efficiency,stability,and reliability of the entire system.A defect detection experiment was conducted on 100 oil tubes of different diameters,and various influencing factors affecting the measurement of the linear laser sensor were analyzed.The experimental results show that the detection system in this paper has high detection accuracy and can be applied to online defect detection of oil tube products,solving the problems of missed and lagged detection of oil tube scratches by manual inspection,and meeting actual production needs.