针对四回路保护阀开启压力调节采用手工调节、自动化程度较低的问题,设计基于机器视觉的四回路保护阀开启压力自动调节测试系统.以LabVIEW为系统上位机开发平台,以可编程逻辑控制器PLC为下位机,通过OPC技术实现LabVIEW动态调用COGNEX智能相机,经NI Assistant相机标定和图像处理、特征提取等算法精确定位四回路保护阀4个排气口中心坐标,并将中心坐标转换为伺服运动系统移动位移量,通过机械臂移动拧紧机构至中心坐标,结合测试系统实现动态调节四回路保护阀开启压力.该系统已投入企业试生产检测,完成多批调试试验,结果表明:该系统运行稳定,满足现场工业对四回路保护阀各排气口重复定位误差≤0.5 mm的要求,测试不确定度为0.168 mm,开启压力调节成功率达95%.%As for the problem of manual adjustment and low degree of automation for the opening pressure regulation of four-circuit protective valve, a test system for automatic adjustment of opening pressure of four-circuit protective valve based on machine vision was designed. LabVIEW was regarded as the upper computer development platform, while the programmable logic controller PLC as the lower computer. The system used LabVIEW to call COGNEX smart camera dynamically with OPC technology, then located accurately the central coordinates of the four exhaust ports of the four-circuit protection valve with NI Assistant camera calibration, image processing and feature extraction algorithm and converted the center coordinates into the servo movement system to moving displacement with which the robot arm moved the tightening mechanism to the center coordinates and it adjusted the opening pressure of four-circuit protection valve in combination with the test system. The system was put into the enterprise trial produc-tion test, completed a number of debugging tests. The results showed that the system ran stably and satisfied the requirement of the field industry that the repeatability positioning error of each exhaust port of the four circuit protection valve was less than or equal to 0.5 mm, and the test uncertainty was 0.168 mm. The success rate of the opening pressure regulation was 95%.
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