The Detection System Of Hydraulic Brake Master Cylinder Surface Defect Based On Machine Vision

As a key component of automotive hydraulic braking system, the performance of hydraulic brake master cylinder directly impacts the stability and security of the brake system. Since the poor processing technology, the newly-produced hydraulic brake master cylinder will generate the defects of brake groove trachoma, chatter and cinder etc. Since these defects can affect the braking performance, it is important to identify the defects of hydraulic brake master cylinder. As we known, the traditional detection method is manual inspection, which has a low detection efficiency and accuracy. To meet the current industrial test demands of hydraulic brake master cylinder, we propose a non-contact measuring method of defect detection based on machine vision technology. The main contents are as follows:1) We proposed a functional defect detection system by analyzing the working principles of hydraulic brake and its defect information. This system includes mechanical module, defection algorithm and program files based on machine vision.2) According to the defection requests, this defect detection system consists of visual sensing unit, mechanical transmission unit, gas loop unit and motion control unit. Among which visual sensing module consist of an imaging system, an image acquisition card, industrial digital cameras and optical lenses, while the mechanical transmission parts includes linear motion control systems and rotary motion, which is controlled by a servo motor and a stepper motor respectively.3) According to the characteristics of hydraulic brake defect groove, its defect detection algorithm were specially designed for blisters, chatter and cinder,. Firstly, the technology of median filtering and projection method are used to edge information extraction of hydraulic brake groove for image pre-processing. Secondly, the algorithm of the area features, projection method and block method are used to identify the images of blisters, chatter or cinder.4) According to the proposed algorithm and system hardware set up, we developed a hydraulic brake groove surface defect detectio n program based on Visual C ++6.0, which consist of parameter setting module unit, the system image processing unit, image acquisit io n system unit, the motor control module and output unit.The experimental results show that there are 25 s used for the detection system, it indicated that the test system meets the functional requirements of the test procedure.