Development Of Measuring And Control System For Automatic Inspected Instrument On Parameters Of Piston Ring

The piston ring is an important part of internal-combustion engine, the tightness between piston ring and cylinder wall has a bearing directly on efficiency of internal-combustion engine. Light-gap tightness degree and end clearance are two important parameters of piston ring. The light-gap tightness degree between the piston and the standard gauge reflects the steam tightness degree domestically while the end clearance of the piston ring which is loaded into standard gauge is also required.So far the inspection of the two parameters is manual work with high intension, low efficiency and low reliability. Advanced optic-electrical detection technology and computer vision technology incorporate with programmable logic controller PLC and HMI man-machine interface are adopted in this project. The automatic measuring and control system of piston ring parameters which achieves automatic, visual and high-speed inspection and sorting of Light-gap tightness degree and end clearance of piston ring is successfully developed.The main work of the thesis includes the following aspects:1. Researching into the traits and difficulties of light-gap tightness degree and end clearance of piston ring according to the requirements in industry field.2. Designing the light-gap tightness degree measuring and data processing system. Selecting hardware devices and designing the light-gap tightness degree measuring hardware system according to the traits of light-gap tightness degree measuring; designing light-gap tightness degree data acquisition and result evaluation software system; designing optic-electricity sensor adjustment system by analyzing and comparing adjustment methods of optic-electricity sensor.3. Designing the data evaluation system. Evaluating the final result of piston ring to provide the basis for sorting movement by embedding the end clearance inspection system and light-gap tightness degree evaluation result.4. Designing communication and control system between embedded computer and PLC. Adopting serial port communication mode which bases on the free port communications to establish the communication system between embedded computer and PLC, making research on the format of data transmission, and proposing the idea that sends binary data in the form of text. In the purpose of enhance communication system stability, a re-issued mechanism after the data error check is established which enhances the efficiency of the instrument greatly.5. Designing CRC(Cyclic Redundancy Check) system. Introducing error control mode, analysing parity check and CRC in auto request repeat mode. Mathematically calculating the CRC at bit and byte level and deducting a 16-bit CRC, accomplishing two engineering algorithms of CRC: bit implementation, byte implementation. The analytical comparison of the reliability of communication between parity check and CRC shows that the CRC is more reliable.6. Accomplishing debugging in industry field, the project is checked and accepted by party A(CSR Qishuyan Locomotive & Rolling Stock Technology Research Institute).