Assembly Of Aircraft Components Research Articles

Fatigue properties of riveted joints under different hole perpendicularity errors and squeeze forces.

Riveting is the most important method of joining sheet metal and is widely used in the assembly of aircraft components. The perpendicularity error of the holes is unavoidable during automatic drilling and riveting, which has a significant impact on the quality of the assembly. In this paper, the effects of hole perpendicularity error and squeeze force on the interference fit size, interface contact state, microstructure morphology, fatigue life, and fracture form of riveted joints were investigated experimentally. The results show that the interference fit size increases with a greater tilt angle. When the tilt angle is 0°, the rivet shank is in close contact with the inner and outer sheets, and there is no obvious gap at the interface between the rivet and the sheets. As the tilt angle increases to 2° and 4°, a gap appears at the interface of regions 1, 2, and 3, while the rivet shank at region 4 is in close contact with the outer sheet. The fatigue life decreases when the tilt angle increases from 0° to 4°. For the same tilt angle, the fatigue life of riveted joints with a 0° tilt direction is higher than that of riveted joints with a 180° tilt direction. Increasing the squeeze force can to some extent reduce the adverse effect of the tilt angle on the fatigue life. The hole perpendicularity error does not affect the failure form, while the squeeze force has a significant effect on the failure form of the specimens. RESEARCH HIGHLIGHTS: The fatigue life of riveted joints decreases as the tilt angle increases. The size of the interfacial gap increases with increasing tilt angle. Higher fatigue life at 0° tilt direction than at 180° tilt direction. Increasing the squeeze force can somewhat reduce the negative effect of tilt angle on fatigue life.

Analysis of Tool Wear and Hole Delamination for Large-Diameter Drilling of CFRP Aircraft Fuselage Components: Identifying Performance Improvement Drivers and Optimization Opportunities

This study provides a comprehensive analysis of the one-shot drilling (CFRP) strategy for machining CFRP materials in the assembly of aircraft components, focusing on key factors such as tool wear, hole delamination, and the evolution of machining forces. The research uses adapted parts of the tail-cone structure of a commercial aircraft as workpieces and employs large-diameter cutting tools to perform drilling operations, with results that can be readily applied to the industry. The study selects cutting conditions by analyzing the effect of cutting parameters on tool life in drilled holes and accumulated cutting time, with the end-of-life criterion based on the extension of the wear suffered by the main cutting edge of the first step. The results show that all tested cutting conditions achieve a similar value of tool life expressed in terms of holes drilled, with differences smaller than 7%. However, one of the cutting conditions analyzed completes the same number of holes within 40% less time. Therefore, considering productivity criteria, it will be interesting to evaluate the use of high values for the cutting parameters. Overall, this research provides valuable insights for improving the efficiency and effectiveness of CFRP machining in aircraft manufacturing.

Advanced Adaptive Spatial Augmented Reality utilizing Dynamic in-situ Projection in Industrial Site Assembly

An Adaptive Spatial Augmented Reality system with dynamic in-situ projection of work instructions and information guidance already shows benefits in the field of industrial site assembly of aircraft components. Furthermore, the user-adaptive gesture control offers advantages for a human-centered and natural interaction directly in the assembly process. This paper presents results of enhancing dynamic in-situ projection, information guidance and user-adaptive gesture interaction in an advanced assembly process of large-sized toy building bricks. For this purpose, the dynamic projection system displays the location of the bricks in the material provision area as well as the accurate mounting position and dynamically guides the operator through the assembly process. Furthermore, the optimized gesture interaction with YOLO and an optimized synthetic dataset creation process for site assembly, indicate strong intentions for user-adaptive interaction with the projection system. An evaluation in the TU Wien pilot factory demonstrates benefits in terms of time savings in locating parts, usability and cognitive workload.

A multi-object posture coordination method with tolerance constraints for aircraft components assembly

PurposeThis paper aims to improve the alignment accuracy of large components in aircraft assembly and an evaluation algorithm, which is based on manufacture accuracy and coordination accuracy, is proposed.Design/methodology/approachWith relative deviations of manufacturing feature points and coordinate feature points, an evaluation function of assembly error is constructed. Then the optimization model of large aircraft digital alignment is established to minimize the synthesis assembly error with tolerance requirements, which consist of three-dimensional (3D) tolerance of manufacturing feature points and relative tolerance between coordination feature points. The non-linear constrained optimization problem is solved by Lagrange multiplier method and quasi-Newton method with its initial value provided by the singular value decomposition method.FindingsThe optimized postures of large components are obtained, which makes the tolerance of both manufacturing and coordination requirements be met. Concurrently, the synthesis assembly error is minimized. Compared to the result of the singular value decomposition method, the algorithm is validated in three typical cases with practical data.Practical implicationsThe proposed method has been used in several aircraft assembly projects and gained a good effect.Originality/valueThis paper proposes a method to optimize the manufacturing and coordination accuracy with tolerance constraints when the postures of several components are adjusted at the same time. The results of this paper will help to improve the quality of component assemblies.

A new method for automatic shaft-hole assembly of aircraft components

PurposeThe purpose of this paper is to design a new method to realize automatic assembly of aircraft components with large shafts such as canard and vertical tail. The assembly structure of component with large shaft and fuselage is a mating assembly structure, and it is a challenge to satisfy the precision and assembly requirement.Design/methodology/approachAccording to the assembly structure features and process requirements of an aircraft component with large shaft, the operating principle of precise assembly system for shaft-hole mating is analyzed in this paper. The model of compliant assembly for shaft-hole mating is constructed, and force condition analysis of the compliant assembly is performed. An automatic precise shaft-hole assembly method for aircraft assembly using 5 degrees of freedom spatial mechanism, compliance technology and servo feeding system is put forward based on the analysis. A 5 degrees of freedom passive compliant experimental equipment has been developed.FindingsApplication test results of the 5 degrees of freedom passive compliant experimental equipment show that the simulated canard can be mated automatically and accurately through this method with high efficiency and high quality as long as the tip of shaft enters into the range of hole’s chamfer.Practical implicationsThis method has been used in an aircraft assembly project. The practical results show that the aircraft components with large shafts can be mated automatically and accurately through this method with high efficiency and high quality.Originality/valueThis paper presents a new method and designs a new assembly system to realize the assembly of the aircraft components with large shafts. The research will promote the automation of fuselage assembly.

Manufacture of Flexible Automatic Assembly Platform for Aircraft Component Level

This paper describes the composition and working principle of aircraft parts flexible automatic assembly platform, and gives the detailed analysis and design of flexible automatic assembly platform of mechanical structure and motion adjusting control system. The two types of multi plane assembly shows that automatic assembly platform automatic adjusting is reliable, operation control system and motion mechanism runs stable, this system can meet the various needs of automatic assembly platform of aircraft components, and it realizes the work mode of assembly and products in one to many during the aircraft components Assembly process.

A posture evaluation method for a large component with thermal deformation and its application in aircraft assembly

Purpose – The purpose of this paper is to propose a posture evaluation approach based on temperature compensation and three-dimensional (3-D) tolerance for the key points (KPs). Design/methodology/approach – A large component 3-D compensation model of thermal deformation considering characteristics of the assembly object is developed. Then, the thermal deformation compensation model is used to modify the nominal coordinates for the KPs. By using a combination of relative deviations of KPs as the objective and 3-D tolerance as the constraints, an optimization model for posture evaluation is established. Findings – Deviations of posture and KPs’ coordinates are obtained by solving the non-linear constrained optimization problem. The posture evaluation method is demonstrated in both a simulation case and practical implication of the aircraft components assembly system with the result that a good performance is obtained. Practical implications – The proposed method has been used in several aircraft assembly projects in China, and gained a good effect. Originality/value – This paper proposes a method for eliminating the affection of thermal deformation during posture evaluation process and improving the consistency and stability of posture evaluation results. The results of this research will help to systematically improve the manufacturing process and tolerance allocation efficiency in large aircraft assembly.

RANSAC Feature Based Master-Slave Tracking System for Multi-AGV

In order to solve the transportation problem in large aircraft components assembly process, an AGV posture synchronization system is built, which utilizes a two-dimensional laser range finder and adaptive control method. Two-dimensional laser range finder is located in the front of AGV to collect real-time point cloud of environment. After tracking AGV section point cloud, we extract straight lines and turning points using the RANSAC algorithm, and estimate the relative posture accordingly. Then adaptive controller processes the position information to achieve master-slave tracking for multi-AGV. In experiment we used three sets of identical AGV; the average distance error was less than 5mm while the angle error was limited within 0.3 °. The results verified the reliability and practicability of our system, which can meet the requirements for transporting large parts.

Simulation of friction stir welding using industrial robots

PurposeThe purpose of this paper is to establish a model‐based framework allowing the simulation, analysis and optimization of friction stir welding (FSW) processes of metallic structures using industrial robots, with a particular emphasis on the assembly of aircraft components made of aerospace aluminum alloys.Design/methodology/approachAfter a first part of the work dedicated to the kinetostatic and dynamical identification of the robotic mechanical system, a complete analytical model of the robotized process is developed, incorporating a dynamic model of the industrial robot, a multi‐axes macroscopic visco‐elastic model of the FSW process and a force/position control unit of the system. These different modules are subsequently implemented in a high‐fidelity multi‐rate dynamical simulation.FindingsThe developed simulation infrastructure allowed the research team to analyze and understand the dynamic interaction between the industrial robot, the control architecture and the manufacturing process involving heavy load cases in different process configurations. Several critical process‐induced perturbations such as tool oscillations and lateral/rotational deviations are observed, analyzed, and quantified during the simulated operations.Practical implicationsThe presented simulation platform will constitute one of the key technology enablers in the major research initiative carried out by NRC Aerospace in their endeavor to develop a robust robotic FSW platform, allowing both the development of optimal workcell layouts/process parameters and the validation of advanced real‐time control laws for robust handling of critical process‐induced perturbations. These deliverables will be incorporated in the resulting robotic FSW technology packaged for deployment in production environments.Originality/valueThe paper establishes the first model‐based framework allowing the high‐fidelity simulation, analysis and optimization of FSW processes using serial industrial robots.