| Piston rod of automobile shock absorber(hereinafter referred to as piston rod),as one of the core parts of automobile shock absorber,plays the role of guiding and supporting in the suspension system.The quality of the piston rod can directly affect the safety and stability of the vehicle.The piston rod is not only affected by axial,lateral reciprocating force and friction force,but also by the design of the wrench mechanism at the end of its body connection.In order to improve the mechanical properties of piston rod,the surface of piston rod was treated with micro-crack and hard chrome plating.Due to poor electroplating and improper handling of piston rod,such as electroplating pores,electroplating fixtures,scratches,etc.resulted in macroscopic flaw on cylinder surface;Due to the improper electroplating process,the micro-crack density on the cylinder surface of piston rod was not qualified.Due to the unmilled or multi-milled structure of the client end wrench caused by the improper operation of the client end milling flat equipment,the client end structure of the piston rod is not qualified.Therefore,these items must be inspected before the piston rod leaves the factory,and must be inspected for each rod except the surface microcrack density of the cylinder.Piston rod products have a large daily output.In order to improve the detection efficiency and realize the traceability of detection parameters,it is of great significance to develop an automated detection system with high efficiency,traceability and high reliability.On the basis of studying the present situation of piston rod flaw detection manually,this paper studies the mechanism of piston rod flaw generation from three aspects: macroscopic flaw of piston rod cylinder surface,microscopic micro-crack of piston rod cylinder surface and client-side flaw of piston rod,and proposes an automatic detection method of piston rod flaw based on vision.An overall scheme of automatic detection,marking and sorting of macroscopic flaw on piston rod cylinder surface by linear scanning vision and motion control technology is proposed.The whole scheme of detecting the micro-crack density of piston rod cylinder surface is realized by laser micro-imaging and image recognition technology.Using the surface array vision and motion control technology to realize the whole scheme of automatic flaw detection and sorting of piston rod client.According to the overall scheme,Soildworks was used to carry out the three-dimensional design of the platform,to select and build the hardware of the visual system,to match and select the dynamics of the motion control system,and to complete the hardware design and construction of the detection system.The software architecture of each detection system is designed,and the functions of the lower machine of the piston rod cylindrical surface macro flaw detection system and the piston rod client flaw detection system are realized by using the PLC programming software,which mainly includes the inking logic control and servo shaft control required by the system.Lab VIEW and its affiliated Vision module and Lab SQL module are used to realize the functions required by the upper computer,including visual detection of piston rod flaw,data storage and communication with the lower computer.Based on the test results,it can be seen from the test results that the line-scan vision is effective in the detection of macroscopic flaw on the cylinder surface of the piston rod,and the detection efficiency,stability and traceability all meet the detection requirements.The visual-based detection system for piston rod cylindrical surface micro-crack density was used for many tests,and it can be seen from the test results that this system has high detection speed,high accuracy and data traceability.A visually based flaw detection device for piston rod client is developed.According to the long-term usage,it can be seen that this device has the advantages of high detection efficiency and good stability,which can meet the testing needs. |
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