Research On Automatic Assembly Technology Of Manipulator For Cap Of Leisure Umbrella

In recent years,with the development of industrial robots,robots have been widely used in the industrial field,and the demand for robot intelligence is gradually increasing.Industrial robots combined with machine vision have significantly improved the level of intelligence,so the combination of vision and robot has become an important direction in the research field.The commonly used method of attitude estimation is to extract feature points for three dimensional reconstruction,but the workpiece with smooth surface and no obvious texture is difficult to achieve attitude estimation by feature points extraction.In the paper the assembly of umbrella parts with smooth surface is studied and tested.Through ellipse fitting and binocular vision positioning based on the established binocular vision system,this paper estimate the position and pose of the umbrella workpiece based on binocular vision,and use the Sinsun SR4 C industrial robot arm to complete the grasping and assembling task requirements of the leisure umbrella workpiece,and conducts trajectory planning and optimization in the task,the automation problem of cap assembly is solved.The main work of this paper shown as follows:An assembly system based on binocular vision to recognize cap workpiece and to grasp and twist the cap with a mechanical arm is designed and the D-H model is established according to the characteristics of the manipulator,the workspace is drawn by monte carlo method,and the forward and inverse kinematics solutions are calculated as well.The established binocular vision system was used to collect the images of the calibration plate,calibrate the internal parameters,add calibration marks on the robot arm,move the robot arm to a set of predetermined positions to shoot the images,and use Tsai's solution method for eye-to-hand calibration to obtain the parameters of the binocular vision system.The target image was processed by Canny edge detection and the binary image was obtained.The camera parameters obtained by calibration are used to identify the ellipse edges of the workpiece fitted by the least square method.The model of camera observation light cone is established and the 3d position and attitude estimation of workpiece in camera coordinate system is obtained by the geometrical property of ellipse projection.Taking the obtained workpiece pose as the grasping position,the trajectory planning and optimization of the assembly tasks of the umbrella cover workpiece,including the clamping operation and the screwing operation,were carried out based on the actual requirements,and the information of the motor in the operation process of the manipulator arm was used to judge whether the umbrella cover was screwing assembly in place.