| The robotic drilling system has been widely used in digital aircraft manufacture for its low cost, high efficiency, and high flexibility. However, the lower stiffness of serial structure will deform under the external forces which has a great influence on the end positioning accuracy. This thesis studies the property of robot drilling redundancy to choose the first and last optimal drilling postures by optimizing the robot posture. In order to determine other drilling postures, the posture smoothness algorithm using the first and last optimal postures as boundary condi-tion is proposed.Firstly, the development and application of the robotic drilling system in digital aircraft are summarized. However, there are still some problems mentioned above existing. So, the property of robot drilling redundancy is exploited by scholars to improve the stiffness of struc-ture by optimizing the robot posture to restrain the end-effector deformation.Introduction in description ways of posture and establishing method of link coordinate system of KUKA KR360-2 are carried out. After research in the reason for various postures and the relationship between posture and deformation, the method of posture optimization and smoothness is proposed in order to improve the efficiency and the hole position accuracy.The input of the robot drilling posture optimization program is the result of the CATIA simulation. Firstly the robot posture will be calculated by inverse kinematics solution when the optimized range of redundancy freedom has been confirmed and dispersed. Then, using the robot simulation model, the sliding deformations of different robot postures are analyzed and compared so that the optimal drilling posture can be obtained.The robot drilling path is planned according to the characteristic of the holes arranging. Then, posture smoothness algorithm using the first and last optimal drilling postures as the boundary condition is proposed in order to determine the other drilling postures. In addition the positioning time and deformation of the smoothness holes are analyzedFinally, through the platform of the robotic automatic drilling system, the deformation test is designed to verify the reliability of the method of robot posture optimization. Then, the op-timized drilling machining program is used to drill holes. Results show that the hole position precision is effectively controlled within ± 0.2mm and the drilling efficiency increases from 5 holes/min to 6 holes/min. The required precision and high efficiency of robot automatic drilling are realized. |
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