Visual Servo System Based On Controllogix

In this paper, after studying related vision servo system theory, I have built a servo system based on computer vision. The servo system is made up of three parts. They are computer vision module, servo control system module and OPC communication module. Subsequently, developing a vision solved method by USB camera and achieving servo control system by programmable logic controller (PLC). In the aspect of system communication, using the OPC technique which broadly adopt in the industrial area.The software of computer vision module is developed by C/C++ based on windows OS and VC++ 6.0. The inputting image is collected by USB camera and the image collected process utilized the Microsoft Video for Windows lib (vfm.lib) to make gray transform. After this, utilizing the Laplcian edge detected operator to detect the efficient edge of the object image. Finally, obtaining the centre of object ball's coordinate by the efficient edge points.Servo control system is the cored module of the whole system. The hardware is mainly constituted of Rockwell A-B Controllogix5550 PLC,1756-M08SE Multi-Axes servo controller,Ultra3000-SE servo drive,Y-1002-2-H servo motor and 01GS001U motion platform.The software is mainly constituted of Rockwell Rslinx and Rslogix5000. PLC acts as the exclusive brain. It can control the servo motor to move logically by some arithmetic. Then, the servo motor drive the motion platform in order to command the object ball's position and trace.OPC communication module realizes the data exchange between the computer vision program and PLC ladder program. Only with this function, we can obtain the real-time trace of the object ball's coordinate. The OPC communication is complied server/client mode. In this paper, the OPC server is Rockwell Rslinx and the OPC client is self-developed based on WTclient.dll which provided by WINTECH company. There are several reasons of choosing OPC technique,. The main reason is OPC's excellent expansibility and universality. And also Self-developing OPC client based on existing OPC server is very popular in the industrial area.