The Servo Control System Based On Digital Image Processing

In this paper, after studying digital image processing theory, constructed a feedback control system based on digital image processing.The system is consist of three parts: the Digital Image Processing model, Servo Control System and OPC Communication. Developed an image processing flow based on USB camara.In order to acquire good communication, OPC technique which broadly adopt in the industrial area is used.The image is captured by USB camara, and its processing is realized on Windows platform and the open source lib OpenCV.In order to make the recognition algorithm to work well, camara calibration which used to compensate the distortion and filter is performed in order to give a better image for recognition. The recognition algorithm have two aims, one is to recognize the Maze which was based on the property of some pixel ;the other is the object on the board which have two methods, recognized by the iterative method and recognize method based on the Hough transform. In this paper the first method is adopted because it is much faster.After the recognition, we can get the maze and the position of the object. In order to make the object in the maze go to the End point, Dijkstra algorithm is used. Its realization is based on two matrixes, and is much faster and less memory is used.Hardware of the Servo control system is 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 controller which controls the servo motor logically according to the specified 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 digital image processing program and PLC ladder program. Only with this function, we can obtain the real-time trace of the object ball's coordinate. 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.