Research On Automatic Inspection Of Crankshaft Flange Of Car Engine

The crankshaft is the core part of the car engine,the production is large,and the precision is high.The precision has a great influence on the quality of the product.However,in the process of production,the crankshaft can only be detected manually.The detection efficiency is low,and labor intention is great.These seriously affect the quality control and management.It is very urgent to realize the means and equipment of 100% online detection.This project originates from the National Science and Technology Major Project of China,and the name of it is "The demonstration project of grinding automation and high efficiency flexible unit for the crankshaft of car engine".In order to meet the needs of multitudinous automatic inspection in industrial scene,it is necessary to complete a set of integrated on-line measuring system for the geometric parameters of the crankshaft of car engine.The measurement of flange parameters is an important part of the detection system.In this paper,the research work on the on-line inspection of the crankshaft flange is carried out.By using the absolute measurement method,a multi camera and large scale visual inspection system is designed by four industrial cameras.The center coordinates of threaded holes and the pin holes can be calculated.Besides the error of experiment measurement is within the range of ±0.04 mm.The method can be used in industrial field measurement,and it can meet the needs of the project.The implementation of the project has laid a good technical foundation for the rapid,high precision,comprehensive and automatic testing of the flange.In addition,the visual inspection is flexible,the design of this system can not only detect a variety of crankshaft flanges,but also detect the geometric parameters and position degree of some large scale workpieces.The main work is as follows:1.Because the requirement of measurement accuracy is high,single camera detection cann’t meet the needs in resolution and precision.Hence a multi camera and large scale visual inspection system is built in this paper,and four local images of flange are collected by the cooperation of four cameras.Then the measuring coordinate system is established and multi-camera data is unified.Therefore,the measurement of the geometric parameters of the flange is completed,and quantitative evaluation and analysis of the geometric parameters of the flange are carried out.2.On the basis of the design and construction of the detection system,a lot of basic experiments have been carried out.The key technical indicators that the system can reach are guaranteed,and the feasibility of the system has been proved.The experiment results show that the single camera calibration error is within the range of ±0.2 pixels,and the global calibration error is within the range of ±0.003 mm.The data detected by the system is compared with the one detected by the Coordinate Measuring Machine,and the error is within the range of ±0.04 mm.Additionally,the flange has been measured 10 times in the same experimental environment,and the range is less than 0.006 mm,and it can meet the detection requirements of the crankshaft.