Research On The Machine Vision And Servo Positioning System

PDP Lighting Inspection Machine is one of important equipments in the PDP production line,which is used to detect the color and brightness of PDP panels.In addition to high precision in processing machinery parts,this machine involves the motion control,visual positioning,network information processing and so on. so it is defined as one of equipments that have the highest degree of difficulty.Based on the project of "PDP Lighting Inspection Machine Localization", this paper firstly analyzes its structure and action procedures; the alignment of electrodes on PDP panel and FPC is needed in order to power on the panel to detect colors,but electrode’s width is only more than ten microns,so positioning system with high precision is required. The location-based visual servo positioning system can meet the demand.Based on the actual task and adopting a "top-down" system design strategy,the guiding location,positioning location and target location are designed in this paper;and a campaign strategy is introduced,which includes location-based visual servo positioning from positioning location to target location,and the stage absolute moving from guiding location to positioning location and from target location to guiding location. Due to meet the campaign strategy,the visual positioning system adopts the positioning control method that combines the location-based visual servo positioning control and absolute position control. For visual closed-loop continuous moving,a point correspondence method is put forward in this paper.This paper also describes the image acquisition, image processing, image feature extraction and off-line teaching process,and analyzes in detail the current, speed and position rings,the dynamic characteristic and parameter setting method of AC servo system. In order to communicate with external controllers,combining RS232with direct input and output is adopted. The communication protocol and task commands are designed. Comminication programs of PLC and PC is also introduced.The visual positioning system has been designed and built in a PDP lighting inspection machine which has been used in a PDP production line.