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

2017 ◽  
Vol 37 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Junxia Jiang ◽  
Chen Bian ◽  
Yinglin Ke
Keyword(s):  
Degrees Of Freedom ◽  
High Efficiency ◽  
New Method ◽  
Assembly System ◽  
Experimental Equipment ◽  
High Quality ◽  
Content Type ◽  
Aircraft Assembly ◽  
Compliant Assembly ◽  
Assembly Structure

Purpose The 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/approach According 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. Findings Application 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 implications This 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/value This 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.

Hybrid fire testing

2018 ◽  
Vol 9 (4) ◽  
pp. 319-341 ◽  
Author(s):  
Ana Sauca ◽  
Thomas Gernay ◽  
Fabienne Robert ◽  
Nicola Tondini ◽  
Jean-Marc Franssen
Keyword(s):  
Stability Problem ◽  
Degrees Of Freedom ◽  
New Method ◽  
Stiffness Ratio ◽  
Fire Testing ◽  
Structural Element ◽  
Content Type ◽  
Surrounding Structure ◽  
Hybrid Test ◽  
The Stability

Purpose The purpose of this paper is to propose a method for hybrid fire testing (HFT) which is unconditionally stable, ensures equilibrium and compatibility at the interface and captures the global behavior of the analyzed structure. HFT is a technique that allows assessing experimentally the fire performance of a structural element under real boundary conditions that capture the effect of the surrounding structure. Design/methodology/approach The paper starts with the analysis of the method used in the few previous HFT. Based on the analytical study of a simple one degree-of-freedom elastic system, it is shown that this previous method is fundamentally unstable in certain configurations that cannot be easily predicted in advance. Therefore, a new method is introduced to overcome the stability problem. The method is applied in a virtual hybrid test on a 2D reinforced concrete beam part of a moment-resisting frame. Findings It is shown through analytical developments and applicative examples that the stability of the method used in previous HFT depends on the stiffness ratio between the two substructures. The method is unstable when implemented in force control on a physical substructure that is less stiff than the surrounding structure. Conversely, the method is unstable when implemented in displacement control on a physical substructure stiffer than the remainder. In multi-degrees-of-freedom tests where the temperature will affect the stiffness of the elements, it is generally not possible to ensure continuous stability throughout the test using this former method. Therefore, a new method is proposed where the stability is not dependent on the stiffness ratio between the two substructures. Application of the new method in a virtual HFT proved to be stable, to ensure compatibility and equilibrium at the interface and to reproduce accurately the global structural behavior. Originality/value The paper provides a method to perform hybrid fire tests which overcomes the stability problem lying in the former method. The efficiency of the new method is demonstrated in a virtual HFT with three degrees-of-freedom at the interface, the next step being its implementation in a real (laboratory) hybrid test.

An adaptive ball-head positioning visual servoing method for aircraft digital assembly

2019 ◽  
Vol 39 (2) ◽  
pp. 287-296 ◽  
Author(s):  
Hua Liu ◽  
Weidong Zhu ◽  
Huiyue Dong ◽  
Yinglin Ke
Keyword(s):  
Visual Servoing ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Sliding Mode ◽  
Full Rank ◽  
System Stability ◽  
Aircraft Structures ◽  
Content Type ◽  
Head Positioning ◽  
Large Aircraft

PurposeTo gain accurate support for large aircraft structures by ball joints in aircraft digital assembly, this paper aims to propose a novel approach based on visual servoing such that the positioner’s ball-socket can automatically and adaptively approach the ball-head fixed on the aircraft structures.Design/methodology/approachImage moments of circular marker labeled on the ball-head are selected as visual features to control the three translational degrees of freedom (DOFs) of the positioner, where the composite Jacobian matrix is full rank. Kalman–Bucy filter is adopted for its online estimation, which makes the control scheme more flexible without system calibration. A combination of proportional control with sliding mode control is proposed to improve the system stability and compensate uncertainties of the system.FindingsThe ball-socket can accurately and smoothly reach its desired position in a finite time (50s). Positional deviations between the spherical centers of ball-head and ball-socket in theX-Yplane can be controlled within 0.05 mm which meets the design requirement.Practical implicationsThe proposed approach has been integrated into the pose alignment system. It has shown great potential to be widely applied in the leading support for large aircraft structures in aircraft digital assembly.Originality/valueAn adaptive approach for accurate support of large aircraft structures is proposed, which possesses characteristics of high precision, high efficiency and excellent stability.

Dual-robot stud welding system for membrane wall

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Youdong Chen ◽  
Qi Hu
Keyword(s):  
Design Methodology ◽  
High Efficiency ◽  
High Accuracy ◽  
Robot System ◽  
High Quality ◽  
Content Type ◽  
Welding Machine ◽  
Stud Welding ◽  
Manufacturing Errors ◽  
Welding System

Purpose The membrane wall is one of the most important components in the boiler industry and numerous studs are welded on its surface. The membrane wall welding still remains a sector intensive in the manual and arduous works. This paper aims to propose a dual-robot system to automatically weld studs on the membrane wall. Design/methodology/approach In this paper, the authors proposed a dual-robot stud welding system for membrane walls. First, the membrane wall is divided into several zones and the welding paths are planned. Then, the pose of the pipes is calculated based on the data measured by light section sensors. The planned paths are compensated by the pose. Finally, the robots weld studs based on the compensated paths. Findings The method effectively eliminates manufacturing errors and welding distortions. The system can weld straight type and L-type membrane walls with high efficiency, high quality and high accuracy. Originality/value The system can weld straight type and L-type membrane walls with high efficiency and high quality. Experiments were performed in a factory to demonstrate the practicability of the method. The dual-robot system with two welding machines has approximately twice the efficiency of the manual welder with only one welding machine. The quality and accuracy of robot welding systems are higher than that of manual welding.

Robustness Evaluation for Compliant Assembly Systems

2003 ◽  
Vol 125 (2) ◽  
pp. 262-267 ◽  
Author(s):  
S. J. Hu ◽  
R. Webbink ◽  
J. Lee ◽  
Y. Long
Keyword(s):  
Process Development ◽  
Simulation Models ◽  
Development Stage ◽  
New Method ◽  
Assembly System ◽  
Assembly Systems ◽  
Compliant Assembly ◽  
Variation Simulation

A new method for evaluating the robustness of compliant assembly systems is developed based on previously developed variation simulation models. This method can be used for selecting a robust assembly system at product/process development stage. Examples are presented to illustrate the proposed method.

Inverse kinematics solution and posture optimization of a new redundant hybrid automatic fastening system for aircraft assembly

2019 ◽  
Vol 47 (1) ◽  
pp. 57-67
Author(s):  
Guowei Pan ◽  
Wenliang Chen ◽  
Hui Wang
Keyword(s):  
Inverse Kinematics ◽  
High Efficiency ◽  
Minimum Energy ◽  
Kinematic Model ◽  
Parallel Robot ◽  
Redundancy Resolution ◽  
Content Type ◽  
Aircraft Assembly ◽  
Multi Objective ◽  
Aircraft Manufacturing

Purpose The purpose of this paper is to use the redundancy of a new hybrid automatic fastening system (HAFS) for aircraft assembly in the best way. Design/methodology/approach First, the kinematic model of HAFS is divided into three sub-models, which are the upper/lower tool and parallel robot. With the geometric coordination relationship, a comprehensive kinematic model of the HAFS is built by mathematically assembling the sub-models based on the DH method. Then, a novel master-slave decoupling strategy for inverse kinematics solution is proposed. With the combination of the minimum energy consumption and the comfortable configuration, a multi-objective redundancy resolution method is developed to optimize the fastening configuration of the HAFS, which keep the HAFS away from the joint-limits and collision avoiding in the aircraft panel assembly process. Findings An efficient multi-objective posture optimization algorithm to use the redundancy in the best way is obtained. Simulation and an experiment are used to demonstrate the correctness of the proposed method. Moreover, the position and orientation errors of the drilling holes are within 0.222 mm and 0.356°, which are accurate enough for the automatic fastening in aircraft manufacturing. Practical implications This method has been used in the HAFS control system, and the practical results show the aircraft components can be fastened automatically through this method with high efficiency and high quality. Originality/value This paper proposes a comprehensive kinematic model and a novel decoupling strategy for inverse kinematic solution of the HAFS, which provides a reference to utilize the redundancy in the best way for a hybrid machine with redundant function.

Robustness Evaluation for Compliant Assembly Systems

2000 ◽  
Author(s):  
Jinkoo Lee ◽  
Yufeng Long ◽  
S. Jack Hu
Keyword(s):  
Process Development ◽  
Simulation Models ◽  
Development Stage ◽  
New Method ◽  
Assembly System ◽  
Assembly Systems ◽  
Compliant Assembly ◽  
Variation Simulation

Abstract A new method for evaluating the robustness of compliant assembly systems is developed based on previously developed variation simulation models. This method can be used for selecting a robust assembly system at product/process development stage. Examples are presented to illustrate the proposed method.

A robot assisted assembly system for small components in aircraft assembly

2014 ◽  
Vol 41 (5) ◽  
pp. 413-420 ◽  
Author(s):  
Zhangjun Jin ◽  
Cijun Yu ◽  
Jiangxiong Li ◽  
Yinglin Ke
Keyword(s):  
Industrial Robot ◽  
Tracking System ◽  
Feedback System ◽  
Assembly System ◽  
Robot System ◽  
Small Component ◽  
Content Type ◽  
Laser Tracking ◽  
Aircraft Assembly ◽  
Loop Feedback

Purpose – The purpose of this paper is to propose a robot-assisted assembly system (RAAS) for the installation of a variety of small components in the aircraft assembly system. The RAAS is designed to improve the assembly accuracy and increase the productive efficiency. Design/methodology/approach – The RAAS is a closed-loop feedback system, which is integrated with a laser tracking system and an industrial robot system. The laser tracking system is used to evaluate the deviations of the position and orientation of the small component and the industrial robot system is used to locate and re-align the small component according to the deviations. Findings – The RAAS has exhibited considerable accuracy improvement and acceptable assembly efficiency in aircraft assembly project. With the RAAS, the maximum position deviation of the component is reduced to 0.069 mm and the maximum orientation deviation is reduced to 0.013°. Social implications – The RAAS is applied successfully in one of the aircraft final assembly projects in southwest China. Originality/value – By integrating the laser tracking system, the RAAS is constructed as a closed-loop feedback system of both the position and orientation of the component. With the RAAS, the installation a variety of small components can be dealt with by a single industrial robot.

scholarly journals An Underwater Image Enhancement Algorithm Based on Generative Adversarial Network and Natural Image Quality Evaluation Index

2021 ◽  
Vol 9 (7) ◽  
pp. 691
Author(s):  
Kai Hu ◽  
Yanwen Zhang ◽  
Chenghang Weng ◽  
Pengsheng Wang ◽  
Zhiliang Deng ◽  
...  
Keyword(s):  
Image Quality ◽  
Image Enhancement ◽  
Quality Evaluation ◽  
High Efficiency ◽  
Natural Image ◽  
High Quality ◽  
Generative Adversarial Network ◽  
Image Quality Evaluation ◽  
Adversarial Network ◽  
Underwater Image

When underwater vehicles work, underwater images are often absorbed by light and scattered and diffused by floating objects, which leads to the degradation of underwater images. The generative adversarial network (GAN) is widely used in underwater image enhancement tasks because it can complete image-style conversions with high efficiency and high quality. Although the GAN converts low-quality underwater images into high-quality underwater images (truth images), the dataset of truth images also affects high-quality underwater images. However, an underwater truth image lacks underwater image enhancement, which leads to a poor effect of the generated image. Thus, this paper proposes to add the natural image quality evaluation (NIQE) index to the GAN to provide generated images with higher contrast and make them more in line with the perception of the human eye, and at the same time, grant generated images a better effect than the truth images set by the existing dataset. In this paper, several groups of experiments are compared, and through the subjective evaluation and objective evaluation indicators, it is verified that the enhanced image of this algorithm is better than the truth image set by the existing dataset.

New Harvesting and Curing Techniques in the Production of Breeder's Seed Peanuts1

1979 ◽  
Vol 6 (2) ◽  
pp. 70-72
Author(s):  
T. A. Coffelt ◽  
F. S. Wright ◽  
J. L. Steele
Keyword(s):  
Large Scale ◽  
Combine Method ◽  
Frost Damage ◽  
New Method ◽  
Experimental Equipment ◽  
Harvesting Method ◽  
Curing Methods ◽  
Labor Requirements ◽  
High Level ◽  
Varietal Purity

Abstract A new method of harvesting and curing breeder's seed peanuts in Virginia was initiated that would 1) reduce the labor requirements, 2) maintain a high level of germination, 3) maintain varietal purity at 100%, and 4) reduce the risk of frost damage. Three possible harvesting and curing methods were studied. The traditional stack-pole method satisfied the latter 3 objectives, but not the first. The windrow-combine method satisfied the first 2 objectives, but not the last 2. The direct harvesting method satisfied all four objectives. The experimental equipment and curing procedures for direct harvesting had been developed but not tested on a large scale for seed harvesting. This method has been used in Virginia to produce breeder's seed of 3 peanut varieties (Florigiant, VA 72R and VA 61R) during five years. Compared to the stackpole method, labor requirements have been reduced, satisfactory levels of germination and varietal purity have been obtained, and the risk of frost damage has been minimized.

Lubricant compatibility of FKM seals in synthetic oils

2019 ◽  
Vol 72 (5) ◽  
pp. 557-565
Author(s):  
Dilek Bulut ◽  
Tatjana Krups ◽  
Gerhard Poll ◽  
Ulrich Giese
Keyword(s):  
Polyethylene Glycol ◽  
Design Methodology ◽  
Elevated Temperatures ◽  
Failure Mechanisms ◽  
Standard Test ◽  
New Method ◽  
Static Tests ◽  
Content Type ◽  
Lip Seals ◽  
First Results

Purpose Elastomer seals are used in many applications. They are exposed to lubricants and additives at elevated temperatures, as well as mechanical stresses. They can only provide good sealing function when they have resistance to those factors. There are many elastomer-lubricant compatibility tests based on DIN ISO 1817 in industry. However, they are insufficient and costly. Correlations between the tests and the applications are inadequate. The purpose of this study is investigating lubricant compatibility of fluoroelastomers (FKM) seals in polyethylene-glycol (PG)- and polyalphaolefin (PAO)- based synthetic oils and developing a methodology to predict seal service life. Design/methodology/approach A new compatibility test which is more sufficient in terms of time and cost was developed and compared with a standard test, currently used in industry. Compatibility of FKM radial lip seals with PG- and PAO-based synthetic oils with different additives was investigated chemically and dynamically. Failure mechanisms were examined. Findings The new method and the Freudenberg Flender Test FB 73 11 008 showed similar results concerning damages and similar tendencies regarding wear. The additive imidazole derivative was the most critical. Static tests give indications of possible chemically active additives, but alone they are insufficient to simulate the dynamic applications. Originality/value The paper describes a new method to investigate elastomer-lubricant compatibility and gives first results with a variety of lubricants.

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