Trajectory Planning of Robot Considering Variation of Convergence Zone Length in Circular Braiding System

Circular braiding is a composite preform manufacturing technology. The structural parameters such as braid angle of composite preform have great influence on its mechanical properties. In the circular braiding system, a robot move the mandrel with a certain trajectory and speed to control the braid angle. Aiming at the problems of unstable braid angle in the process of braiding complex mandrel, a trajectory planning method of robot is proposed. Firstly, a yarn deformation model in process of circular braiding is developed to calculate the real-time actual convergence zone length. Then, based on the variation of the convergence zone length and the spatial geometric relationship that the center line of the mandrel is always perpendicular to the braiding plane, the trajectory points of robot in the mandrel coordinate system are solved. Finally, the trajectory points in the robot coordinate system are obtained by a series of coordinate system transformations. The experimental results show that, with corresponding take-up speed profile, the trajectory planning method can effectively reduce the braid angle error of curved mandrel and variable cross-section mandrel within ± 2°, which can improve the quality and efficiency of composite preform production.