Optimal Design Of Key Structure Of Automatic Riveting End Effector And Research On Pressure Riveting Process

With the rapid development of aviation manufacturing industry,the requirements for component size,assembly accuracy and processing quality are increasing.Robotic automatic drilling and riveting systems are widely used in the aviation manufacturing field.As one of the core components of the robotic automatic drilling and riveting system,the performance of the automatic riveting end-effector directly affects the processing quality and efficiency of the whole system,and stable and reliable automatic riveting equipment has become the future development trend.In the process of making holes in aircraft structural parts riveting assembly,the domestic riveting end-effector riveting method generally uses air riveting,pneumatic riveting mainly has a simple mechanism,strong and light,but its shortcomings cannot be ignored,such as the existence of uneven nail rod expansion,vibration and other shortcomings.In this paper,we propose a new technology for the development of robotic automatic riveting end-effector based on electric pressure riveting technology for the riveting of large aviation structural parts,a type of cockpit cover.The main research contents are as follows.(1)For a certain type of cockpit cover riveting task,a detailed analysis of its processing requirements and workflow is made,the overall design of the automatic riveting end-effector is proposed,and the structural design of the riveting end-effector is realized.A mathematical model of the relationship between friction and structure in the key drop nail structure is proposed,and theoretical modeling and analysis of the press rivet structure is carried out.(2)In order to reduce the mass of the end-effector and the impact on the positioning accuracy of the robot,the weight reduction of the equipment is optimized under the premise of ensuring the strength.According to the technical standard of 2A10 rivet aerospace pressure riveting force,for the main force structure,the finite element simulation software was used to conduct static analysis as well as the eigenvalue buckling analysis of the slender shaft structure,based on which the structural optimization was completed and the weight was reduced.(3)In order to obtain the riveting parameters and improve the riveting quality,the dynamic process of 2A10 rivets for aviation was simulated and analyzed by finite element method.According to the riveting structure and the principle of press riveting,the finite element simulation model of press riveting process is established in ABAQUS,and the relevant analysis and solution are completed.This paper focuses on the dynamic process of stress,plastic strain and displacement of rivets and riveted parts in the process of press riveting,extracts relevant numerical results,and obtains important press riveting displacement parameters,which provides theoretical basis and data support for the process of press riveting.(4)In order to ensure that the developed riveting end-effector can successfully achieve the riveting task and that the riveting quality and performance meet the riveting requirements of the cockpit cover,a simplified riveting experimental bench device with the same driving force and riveting structure as the riveting end-effector was pre-developed.The riveting experimental device can detect the riveting force in real time,and a series of riveting tests were conducted.The test results show that the simulation model and analysis of the riveting process are correct,the electric drive can achieve the riveting quality and performance requirements,the riveting structure is reasonable,and the developed riveting end-effector can realize the requirements of automatic riveting based on the robot cockpit cover.