Research On Automation System Of Precision Assembly For Coronary Stent Gold Radiopaque Marker

Coronary artery heart disease is one of the major dangerous diseases to man.Coronary stent is an effective treatment for the disease.Its detection in interventional therapy can be effectively performed by the radiopaque marker at DSA.At present,the assembly of radiopaque marker is performed under the microscope,with the defects of precise positioning,poor product stability,serious scrap rate and low production efficiency etc.With the rapid development of automatic precision assembly technology and machine vision technology,the use of automatic assembly system to replace artificial assembly radiopaque marker can solve the above problems.This paper studies the automatic assembly system of precision assembly for coronary stent gold radiopaque marke r.Its program is proposed,the motion control system is established,the related image processing algorithm is designed,and the experimental analysis is carried out.According to the functional requirements of radiopaque marker assembly system,the assembly process plan is determined.Then,the original mechanical structure is improved,the function of the motion axis is analyzed,and a visual inspection platform is built at the same time.The overall program of motion control system is proposed,the open control mode of PC-based motion control card is determined,the hardware construction and control circuit design are also done.Use the method of semi-closed-loop motion control to achieve the motor control and biaxial synchronization control.Pressure testing and sensor calibration are performed and the control program for cutting and pressing radiopaque markers are established.PC control software is programmed to achieve the entire movement of the automation process control.In order to ensure the accuracy of visual inspection,the camera related parameters are calibrated.The image processing related algorithms are designed by the positioning and identification needs of radiopaque holes and radiopaque markers.The image smoothing algorithm is improved b y using the gradient enhancement,and the complex texture of the coronary stent is removed effectively.An algorithm is proposed for positive positioning detection of radiopaque holes based on rough positioning and precision positioning,and the problem that radiopaque holes faces upwards was solved during assembly.In addition,the defect detection algorithm is proposed for the radiopaque marker placement,which can well determine whether its placement is reasonable.Finally,based on the entire radiopaque marker assembly system,the related confirmatory experimental tests are carried out,including the experimental test analysis of the positive positioning detection of radiopaque holes,the repeated positioning accuracy and automatic assembly test.The experimental results show that the design about the automatic assembly system of precision assembly for coronary stent gold radiopaque marker can meet the design needs.