| The aircraft integral reinforcement frame plays the role of main bearing capacity and main positioning in the assembly process of fuselage components.Its stiffness is higher than that of other parts of the aircraft.When the peripheral profile is assembled and coordinated with other parts,the same positioning gap will produce greater assembly stress,which will cause difficulties in subsequent assembly and positioning operation,reduce the assembly accuracy of components and bring the stress corrosion,and even reduce the strength and life of the aircraft.In order to ensure the assembly accuracy of aircraft fuselage components,it is necessary to exponentially improve the positioning quality of large integral structural components.To address manufacturing differences,change the poor control of the positioning process and the low reproducibility of the positioning results caused by traditional forced positioning,ensure the positioning quality of large integral structural components,an adaptive flexible positioning method based on force control technology is proposed.This paper takes the scaled-down half-frame of integral reinforcement frame of a certain type of aircraft as the research object,deeply analyzes the positioning process of the aeronautical integral reinforced frame,quantifies the positioning quality inspection standards,selects the process parameters control method,builds a digital flexible positioning test platform,adjusts the coordinate positioning hole heading coordinates of non-determined stations within the design allowance to obtain the best assembly positioning quality,studies the scheme of assembly positioning force-load inspection instead of stress inspection to evaluate the assembly quality,and obtains the assembly positioning force-load adjustment target.(1)Analyzed the assembly process characteristics of fuselage components,obtained the assembly and positioning quality requirements of the aeronautical integral reinforcement frame.Determined the positioning process control process parameters and quantify the positioning quality evaluation criteria by combining the structural characteristics of the aeronautical integral reinforcement frame.Studied the digital flexible positioning technology of the aeronautical integral reinforcement frame,determined the adaptive assembly and positioning scheme based on force control technology,and designed the digital measurement scheme of positioning quality.(2)According to the research objectives and available experimental equipment,designed and processed the test parts of the scaled-down half frame of integral reinforcement frame,and carried out the deformation simulation analysis.Based on the assembly and positioning process scheme of the integral reinforcement frame and the digital measurement scheme of the positioning quality,designed and built the digital flexible positioning test platform,and studied the shaping mode,hardware selection basis,control scheme,position coordinate value,assembly force load value and stress value detection scheme.(3)Based on simulation software ANSYS,the deformation of integral reinforcement frame was analyzed qualitatively,and the feasibility of the test was analyzed by photoelastic detection.With the objective of minimizing the quantified value of the positioning quality evaluation standard of the aeronautical integral reinforcement frame,orthogonal tests were designed to optimize the optimal assembly positioning process parameters by taking the deviation of the coordinate positioning holes at non-determined stations as the investigating factor;analyzing the variation law of the absolute average value of force load at the coordinate positioning holes at non-determined stations and the absolute average value of stress at the positioning detection points,and conducting the assembly site easily accessible force load instead of stress value correction assembly The feasibility study of the quantitative formula of the positioning quality evaluation standard was conducted to obtain the target of force load adjustment at the coordinate positioning hole and guide the assembly positioning of the integral reinforcement frame of aviation. |
