Research On Vision-based Dispensing Machine

The dispenser is a machine which dyes the surface or holes in the product with paint or other stains,it is widely used in processing jewelry,badges,hardware,chess and electronic components.At present,there are still a large number of related enterprises using manual dyeing way.Therefore a fully automated dispensing machine which has the advantages of high accuracy and good stability will be designed,which instead the traditional manual dyeing and improves the efficiency.The machine vision technology is applied in the design of the automatic dispensing machine,which successfully controls the dispensing movement and the dispensing position.The main research work of this paper is as follows:1.It proposes and implements a shape-based template matching algorithm.By using the Sobel operator to filter the template image and the search image,the vectors of the edge points of both images are obtained.The inner product of the template edge points and the corresponding points of the search image is the result of similarity measurement.Analysis shows that the method resists occlusion,chaos and the change of illumination effectively.In the search strategy,the image pyramid search method which carry out "Rough match " in the upper level and "fine match" in the lower level is used to improve the matching speed.2.Through the data fitting,the relationship between the number of calibration images and the accuracy of the camera calibration is given.The improved model for the lens distortions which uses three parameters to describe the radial distortion and two parameters to describe the eccentric distortion was presented,its calibration accuracy is higher than the traditional split distortion model.3.It uses the method of capturing the origin limit switch and the Z-phase pulse to improve the accuracy of the robot reset.it designs the data transmission method which transfers the track points and the center coordinates of template to the controller previously and only transfers the center coordinates and rotation angles of the products in later processing,comparing to transfer all processing points of all products,improve the transmission efficiency.4.It introduces the development environment of dispensing system software--.NET platform and C#language.The whole system is designed in C#language,including camera control module,learning sample module,image matching module,camera calibration module,hand-eye calibration module,control PLC module and automatic processing module.With the C#visual interface,different modules are connected and the design of entire dispensing system is completed.5.It performs a performance test on the dispensing system.In the motion control,it is mainly about mobile repeat accuracy and continuous discharge.Through the analysis,it is concluded that the problem straight line is uneven is caused by unavoidable acceleration and deceleration of the servo motor.In the visual control,it is mainly about camera calibration accuracy assessment and verifying the image positioning accuracy and hand-eye calibration accuracy.In the paper,the vision technology is used in the dispensing process,a fully automatic dispensing machine is developed and it realizes the precise control of the dispensing movement and the dispensing position.