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

The engine is one of the key core components in aircraft, in order to enhance automation and efficiency in the process of installation and disassembly for current small engine, using automatic control technology, a set of automatic disassembly and assembly system for aircraft engines is developed to replace the traditional mechanical installation vehicle. Corresponding for small engine to study the automatic disassembly system, the system uses laser sensors to locate the engine disassembly and assembly. Servo motors are used to drive the walking mechanism, lifting mechanism, and fine-tuning mechanism to realize multi-degree-of-freedom adjustment during engine disassembly and assembly. And the digital video is used to monitor the gap collision. Finally, the paper realizes the automatic high-precision disassembly and assembly of small engines. Through verification, the efficiency of the disassembly and assembly system has increased by more than 70%, the work efficiency has been greatly improved.

The automatic assembly of photo products has been developed by Nikon Corp. over more than ten years. Automatic assembly methods are historically classified into three categories: dedicated machines, semi-flexible automatic assembly systems, and universal automatic assembly systems. This paper surveys these types of automatic assembly systems. First, automatic assembly systems for mechanical components of photo products are considered, and their background and design policies discussed. Next, the performances of these assembly systems and the results achieved in practise are described. Finally, the future trends of photo product automation are outlined.

The assembly of the wedge belt joint relies on the sense and experience of human, which limit the application of automatic assembly technology. In order to implement automatic assembly for higher production quality and efficiency, an assembly status identification method based on dynamic feature is proposed. The contact status of the wedge belt in assembly is analysed and the dynamic model is formulated. The dynamic features for identification are compared and the signal of acceleration is selected. The identification method of assembly status is proposed based on the acceleration signal. An experiment is designed to verify the identification method. The experiment result shows that the amplifier of the acceleration decreases much more sharply as it fits well. The proposed identification method is effective and stable, which could be used for the automatic assembly.

The rationalization efforts made in the field of assembly have been intensified in recent years. The different assembly operations arising due to short production period and diversity of variants can mostly be automated “flexibly” only. The public discussion so far has been dominated by the technical shortcomings of the automation means (e.g. lack flexibility of peripheral equipment) and the loss of working places to be expected. But the issues of the work organizational integration of flexibel automation means in the assembly system are of equal importance. This is reflected in a study (1) made on behalf of the Federal Ministry for Research and Technology.

The helicopter fuselage has the characteristics of compact structure space, complex coordination relationship and weak rigidity, etc. It is difficult to control the accuracy of the desired shape. According to the high precision and quality requirement of final assembly for helicopter fuselage, the application status of automatic assembly technology in aviation manufacturing was analyzed. Then the difficulties of automatic assembly technology for fuselage final assembly were also discussed. In this paper, an automatic assembly system for the final assembly of helicopter fuselage was designed, and relevant key technologies of the assembly system mentioned above were proposed. The designed system have the functions of automatic positioning, clamping, measuring, drilling, feeding and blind fastener riveting for fuselage components, which can improve the assembly quality and efficiency of helicopter fuselage during the final assembly process.

Development of a novel integrated automated assembly system for large volume components in outdoor environment

In this article, the assembly of axi-symmetric rigid structures from imprecisely manufactured components is considered to produce a ‘straight-build’ assembly. The eccentricity of the assembly is improved by selecting the best relative orientation of each component and using four different strategies to control the assembly errors. The presentation is simplified by considering the assembly of two-dimensional structures, and the Monte Carlo simulation technique is used to quantify the propagation of random component variations on the resulting assembly. The axial and radial run-outs for each component are used to represent component variability and these quantities are represented as Gaussian random variables. The influence of component variations on the assembly is predicted using connective assembly models. Numerical results are presented for assemblies consisting of: (a) identical rectangular components; and (b) non-identical rectangular components. The results are compared with each other and those obtained using ‘direct-build’ assembly, which does not control the assembly errors. It is found that assembly variations can be reduced significantly using the proposed techniques.

Large shaft usually achieves high surface quality through multi-pass grinding in practice. Common surface quality indexes include surface roughness and glossiness, which are not only required numerically, but also require high consistency of distribution along the whole shaft. In multi-pass grinding, these two indexes are affected by the process parameters and the surface quality of the previous grinding pass, which leads to the difficulty of modeling. In addition, due to the uneven distribution of actual grinding depth, the surface quality along the whole shaft is usually inconsistent, resulting in the need for multiple spark-out grinding passes to ensure consistency. In this study, the surface quality evolution models for surface roughness and glossiness based on Elman neural network are developed, which build regressions between process parameters, surface quality indexes of the previous grinding pass, and surface quality indexes of the current grinding pass. Moreover, a consistency control method of surface quality is proposed by adjusting the actual grinding depth within the dimensional accuracy tolerance range at the rough grinding stage. Experimental results show that the surface roughness and glossiness prediction errors of the surface quality evolution models are only 5.5% and 5.1%. The consistency control method guarantees the consistency of surface quality, reduces the grinding passes, and increases the grinding efficiency.

Aircraft assembly is challenging to ensure accuracy and feasibility due to its numerous components and stringent quality requirements. The assembly assistant system with computer vision has advanced rapidly. However, there is a lack of the dataset required for object detection because of the confidentiality of aircraft components, resulting in a degraded performance of the assistant system. In this paper, we proposed a mixed aircraft component dataset (MACD), including real photos and synthetic images. We adopted Squeeze and Excitation (SE)-YOLOv5 by introducing the SE-Layer into CSPDrkNet53 to improve object detection accuracy. In addition, we defined the price-performance ratio (PPR) as a measure of dataset quality. We also developed an augmented reality assembly assistant system that offers simple and convenient assembly assistance and can improve assembly efficiency and quality.

Virtual trial assembly of a complex steel structure by Generalized Procrustes Analysis techniques

The results of the analysis of the possibility of using known methods for assembling the components of an aircraft airframe, containing, in particular, elements of composite materials (CM), are presented. The features of structures made of CM and their joints, which affect the subsequent assembly of such structures, are considered. Systematized information about the terminology in the home area. Alternative formulations of assembly-related terms are proposed.Some features of the choice of methods for assembling structures containing elements from CM are considered. The properties of CM that influence the choice of assembly bases are analyzed. Potentially possible bases for assembling components of aircraft structures from CM, as well as CM and metals in different proportions, in particular, the method of assembly using virtual bases, are proposed. The classification of methods for assembling aircraft all-metal structures is carried out, technological limitations of CM are indicated, which have a direct impact on the use of the corresponding elements of assembly equipment. Some cases of imitation of design solutions of aircraft structures made of metals into structures containing elements of CM are considered. The typification of the main assembly units of the airframe of the aircraft has been made, in terms of orientation to certain assembly methods.Formulas for calculating the value of the total error in the assembly of components made of metals are proposed. The factors influencing the magnitude of the total error for CM structures are substantiated. The current trends in the use of CM at the SE «ANTONOV» are formulated in an enlarged way. An adaptive scheme for choosing a method for assembling assembly units containing, in particular, elements from CM, obtained by extrapolation from all-metal structures, has been developed.Conclusions are drawn about the need to orient the developed aircraft structure to a certain assembly method, and the main conditions for carrying out assembly work on composite parts from CM are formulated. The possibility of assembling aircraft structures from CM, as well as CM and metals in different proportions, with predominantly based on holes using simple assembly equipment, has been determined.

PurposeThis paper aims to present a modeling and analysis approach for multi-station aircraft assembly to predict assembly variation. The variation accumulated in the assembly process will influence the dimensional accuracy and fatigue life of airframes. However, in digital large aircraft assembly, variation propagation analysis and modeling are still unresolved issues.Design/methodology/approachBased on an elastic structure model and variation model of multistage assembly in one station, the propagation of key characteristics, assembly reference and measurement errors are introduced. Moreover, the reposition and posture coordination are considered as major aspects. The reposition of assembly objects in a different assembly station is described using transformation and blocking of coefficient matrix in finite element equation. The posture coordination of the objects is described using homogeneous matrix multiplication. Then, the variation propagation model and analysis of large aircraft assembly are established using a discrete system diagram.FindingsThis modeling and analysis approach for multi-station aircraft assembly reveals the basic rule of variation propagation between adjacent assembly stations and can be used to predict assembly variation or potential dimension problems at a preliminary assembly phase.Practical implicationsThe modeling and analysis approaches have been used in a transport aircraft project, and the calculated results were shown to be a good prediction of variation in the actual assembly.Originality/valueAlthough certain simplifications and assumptions have been imposed, the proposed method provides a better understanding of the multi-station assembly process and creates an analytical foundation for further work on variation control and tolerance optimization.

This paper addresses the development of organizational multi agent systems as a preferred solution to develop open, distributed and adaptive application. It proposes a combination between components and agents to define a flexible organizational model of MAS based on three concepts: roles, self-adaptive agents based on components and fuzzy groups. Roles are played by agents in fuzzy groups. A fuzzy group is a fuzzy set of agents characterized by a membership function expressing the partial membership of each agent to the group. The membership function expresses the degree of capacity of each agent to play a role. This work proposes a fuzzy measure of the capacity of agents to play roles. It proposes a model of auto adaptive agents constructed by automatic assembly (reassembly) of software components. Components implement required capabilities to play roles. The proposed model and introduced concepts have been tested using the Madkit platform.

Robotic assembly of architectural structures has been an area of research for a few decades. Yet, current methods impose a large number of constraints on the geometry of those structures. In this paper we introduce a method for robotic assembly that enables the construction of double curved self-supporting structures. Latest research challenges have focused on the assembly of sophisticated brick structures and on sensor feedback systems for handling accuracy. We propose an alternative strategy to tackle tolerance handling in complex structures that rely on geometry. The intelligence of the system lies in two main aspects: a subdivision technique that incorporates the robot’s constraints as well as the structural equilibrium of the structure during each step of assembly, in order to omit the use of scaffolding; and a match between geometric information and the robot’s movements in a robot programming environment. As a proof of concept, we fabricated a portion of a full-scale double-curved structure. The structure was assembled without scaffolding by a portable KUKA KR10 on a randomly picked site. This project aims to demonstrate an easy and simple method for robotic assembly that enables the realization of digitally generated complex geometries as concrete complex structures.

<div class="htmlview paragraph">In this paper solution for low-cost automation of aircraft assembly is presented. The concept of this development is closely related to “Lean Automation”, which in this case concerns the use of modern standard equipment such as standard robots, PC-computers and a newly developed spatial sensor system for precision measurements of positions. The robot is used to perform reconfiguration of tooling modules that are possible to be configured/reconfigured in six degrees of freedom. A prototype developed as the result of an EU-project called ADFAST* has been evaluated at Linköping University in Sweden. Technical functionality is reported where the robot manages to configure the flexible tooling modules to a total error bellow 50 μm. This paper presents the results on the portion of the project addressing robot, metrology system and tooling.</div>