Sewing Robot Three-dimensional Curved Fabric Seam Extraction And Process Coordination

In order to improve the flexibility of the stitching robot for composite preforms,a novel visual joint extraction technology was studied,for solving the automatic path planning issues of the stitching robot.The visual joint extraction technology is based on 3-D raster scanning technology and is applied in composite fabric with curved surface.combined the robot,the end of suture unilateral and three-dimensional scanning device Based on the structure of Eye-to-hand,the robot,one-side sewing device and 3-D raster scanning device would be composed of hand-eye system,and the point cloud data of preform could be obtained.According to the data,the suture position of stitching robot can be solved by the point cloud processing and autonomous planning algorithm.Relying on the characteristics of the unchangeable view field of 3-D scanning camera,the calibration experiment of the camera was carried out.This can improve the conventional hand-eye calibration method,propose a novel four-point calibration method to solve the hand-eye relation matrix,and then establish the posture mapping relation between the robot coordination and camera coordination systems.Through the improved hand-eye calibration and sampling with 3-D raster scanner,the point cloud data from the stitched preforms can be converted into the point cloud data coordinates in the robot coordination system.Then the feature of point was extracted by the feature extraction algorithm,and the center-line could be obtained by calculation.An algorithm for the stitching trajectory and posture planning was proposed.The proposed algorithm uses cubic polynomial for fitting the center line of joint and the least square method for fitting the stitched micro tangent surfaces,completes the calculation for the tangent and approaches vectors in robot operational space.Finally,according to the stitching position which obtained by the autonomous planning algorithm,designed needle movement and robot motion coordination control system by using Siemens PLC.Based on profibus field bus communication technology,the network control strategy was adopted to accomplish the data exchange between the various devices.The stitching experimental results show that the system can meet the requirements of the actual sewing process.