On-line 3D Workpiece Size Reduction And Positioning Measurement For Industrial Robots Based On Binocular Vision

With the continuous change and development of intelligent manufacturing technology,the application of robots has gradually penetrated into various fields.The combination of industrial robots and vision gives the robot the ability of interactive perception with the external environment.Visual technology from the original monocular vision,to today's binocular vision,multi-vision.Binocular vision has been widely studied for its accuracy of measurement results,convenience of experimental operation and diversity of application scenarios.In this paper,based on binocular vision technology,three-dimensional dimension reduction and spatial positioning of industrial robot on-line target workpiece are studied.Firstly,the imaging model of binocular vision sensor is established,and the projection matrix of camera sensor is deduced.By comparing the accuracy of calibration results and the difficulty of calibration process between the two imaging calibration toolkits of MATLAB and Halcon,a calibration programming method based on MATLAB is selected.In the aspect of three-dimensional dimension restoration,firstly,aiming at the particularity of the research object and application scene,a feature detection algorithm based on contour edge line fitting is proposed to obtain the image coordinates of the left and right feature points of the workpiece.Secondly,based on the stereo matching algorithm of the minimum distance between the common perpendicular line and the non-planar straight line,the accurate matching of the corresponding feature points in the left and right image of the target workpiece is realized.Finally,aiming at the problem that large and multi-surface workpieces can not be measured completely in the process of three-dimensional dimension reduction,a reconstruction method based on overlapping feature points is proposed Three-dimensional dimension reduction measurements for different types of workpieces,such as tetrahedron,hexahedron,bolt and cylinder,are carried out The measurement accuracy can reach 0.5 mm.In the aspect of workpiece space location,based on Eye-in-Hand hand-eye calibration results,a visual location method based on affine transformation model of known points is proposed.Spatial positioning calculation is carried out for workpieces with different shapes and sizes.Laser displacement sensors are loaded at the end of the robot.Error measurement experiments in three directions,X,Y and Z,are carried out under the feedback of positioning information.The positioning accuracy is about 0.6 mm by analyzing the experimental results.