The Design And Implementation Of The Robot Positioning And Grasping System By Visual Guidance

In industrial production,the robot is usually able to complete the task of locating and grabbing by teaching in advance.However,when the position of the workpiece changes,the robot will not be able to accomplish the task.Therefore,the traditional method has some disadvantages,such as poor flexibility and so on.The vision system is installed on the industrial robot to introduce the visual information into the robot.The control of the robot by the visual information can improve the flexibility and real-time performance of the robot.In this paper,a monocular vision system is installed on the ABB robot body to capture the image of the workpiece.The HALCON machine vision software locates the grab point of the workpiece through the image processing technology,and sends the visual information to the industrial robot through Ethernet.The robot is guided by visual information to complete the task of locating and grasping.The main tasks are as follows:1.Eye-in-Hand monocular vision system(camera,lens,light source)is used to capture the image of calibration board and record the pose of robot.The hand-eye calibration of Eyein-Hand system is carried out,and the transformation matrix of camera coordinate system and robot tool coordinate system is obtained.2.Collect the workpiece image,firstly locate the pixel coordinates of the workpiece grabbing point by image processing technology,then define a reference coordinate system,and obtain the coordinate value of the grabbing point in the reference coordinate system through the camera internal reference.Finally,using the transformation matrix obtained by the hand-eye calibration,the coordinates of the grab point are converted to the pose under the robot base coordinate system,and the visual positioning of the workpiece grabbing point is completed.3.The host computer is programmed,and the visual positioning program of the workpiece grab point is invoked.The communication between the host computer and the robot is realized by socket(socket)communication.The grab point coordinates of the workpiece are sent to the robot and the communication status between the two sides is monitored.4.The robot receives,analyzes the position data of the workpiece grab point sent by the upper computer,and realizes the robot moving from the visual information to the grasping point of the workpiece.The IO board and IO signal of the robot are configured.The robot tool(sucker)is controlled by the IO signal to complete the grabbing and placement.