Design And Analysis Of Automatic Drilling System With 5-DOF For Aircraft Assembly

With the rapid development of aviation industry, production requirements of high quality, high efficiency and low cost in aircraft manufacturing assembly technology are needed. The connector on the plane is thin-walled structure with large size and complicated shape. Thus the holes’ quality is difficult to be guaranteed. Posture alignment and vertical feeding of the end executor need to be implemented for automatic drilling on large thin-walled surface. Due to accurate precision, large bearing capacity, flexible dynamic performance and other characteristics of parallel mechanism, research for its application to aircraft assembly automatic drilling system could be of great significance.Firstly, in order to meet the requirements of manufacturing aircraft wing with two curvature surface, a system of automatic drilling based on hybrid mechanism was designed, using screw theory of institution analysis method. The DOF of x, y, z direction and A, B axis of rotation of the system can be obtained which could meet the requirements of automatic drilling.Secondly, the 3-RPS parallel mechanism kinematics was analyzed. Position inverse solution model of the system was established by closed method and velocity and acceleration of the mechanism were analyzed based on the influence coefficient method of screw theory. Furthermore inverse solution solved by ADAMS software is verified and velocity and acceleration’s performance were simulated.Thirdly, considering condition of generating singularity the singular positions of 3-RPS parallel mechanism were analyzed. Based on the inverse kinematics analysis, the position workspace of the 3-RPS parallel mechanism was obtained by searching the boundary of the possible working area constrained by serious conditions. Furthermore the effects of radius ratio between dynamic and fixed platform for working space was analyzed.Finally, due to the influence of uncertain factors such as spherical, rotation vice clearance and manufacturing errors of the actuating bar, pose error model of the mechanism was established. The interval analysis of probabilistic robust optimization method was used to optimize actuated volume, which improved the posture and position precision of the system.