Motion Control Technology Of Twin-robot Ultrasonic Testing System Of Non-Rotation Workpiece

With the continuous development of industrial manufacturing technology,the application of non-rotating complex curved surface workpiece in the aerospace and defense industry becomes more and more widely.Due to the special shape of this kind of workpiece,the ultrasonic nondestructive testing used to detect its internal defects has mainly relied on manual detection methods.These manual methods require workers' experience and have a plenty of drawbacks,including lack of visualization,difficult to judge defects,inconvenient to record and full of human impacts.Because it is difficult to achieve uniform position detection when using manual methods,it is inevitable that there is high rate of undetected position and unstable quality of flaw detection.This cannot meet the modern industrial ultrasonic testing requirements,which are high efficiency,high precision and high reliability.Industrial robot technology has been widely used in industrial manufacturing because of its high precision,high flexibility,high automation and repeatable programming.The combination of ultrasonic nondestructive testing technology and industrial robot technology can take advantage of the characteristics of the robot.It can promote the development of ultrasonic automatic detection technology.This paper aims to research the ultrasonic transmission detection system for non-rotating complex curved surface workpiece,which is based on twin-robot.During the process of automatic testing,it is necessary to ensure that the two robot arms move in the same workpiece coordinate system.Because of the limitation of the complex curved surface's structure,it is difficult to calibrate the workpiece coordinate system by the traditional calibration methods.Therefore,it is necessary to study the calibration method of twin-robot's workpiece coordinate system.In addition,in the actual detection process,as there are some structural interference problems between the robot body and the workpiece,the movement of the robot is limited.Therefore,in the actual movement,the movement expansion axis needs to be added to the robot arm's end to complete the detection task.The redundancy degree of freedom for the robot arm's movement is increased with the adjunction of this axis.After using the traditional way to complete the trajectory planning of robot movement,it is necessary to reallocate the movement so as to guarantee accurate position and attitude of robot arm's movement.