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Article
Publication date: 16 April 2024

Yang Liu, Xiang Huang, Shuanggao Li and Wenmin Chu

Component positioning is an important part of aircraft assembly, aiming at the problem that it is difficult to accurately fall into the corresponding ball socket for the ball head…

60

Abstract

Purpose

Component positioning is an important part of aircraft assembly, aiming at the problem that it is difficult to accurately fall into the corresponding ball socket for the ball head connected with aircraft component. This study aims to propose a ball head adaptive positioning method based on impedance control.

Design/methodology/approach

First, a target impedance model for ball head positioning is constructed, and a reference positioning trajectory is generated online based on the contact force between the ball head and the ball socket. Second, the target impedance parameters were optimized based on the artificial fish swarm algorithm. Third, to improve the robustness of the impedance controller in unknown environments, a controller is designed based on model reference adaptive control (MRAC) theory and an adaptive impedance control model is built in the Simulink environment. Finally, a series of ball head positioning experiments are carried out.

Findings

During the positioning of the ball head, the contact force between the ball head and the ball socket is maintained at a low level. After the positioning, the horizontal contact force between the ball head and the socket is less than 2 N. When the position of the contact environment has the same change during ball head positioning, the contact force between the ball head and the ball socket under standard impedance control will increase to 44 N, while the contact force of the ball head and the ball socket under adaptive impedance control will only increase to 19 N.

Originality/value

In this paper, impedance control is used to decouple the force-position relationship of the ball head during positioning, which makes the entire process of ball head positioning complete under low stress conditions. At the same time, by constructing an adaptive impedance controller based on MRAC, the robustness of the positioning system under changes in the contact environment position is greatly improved.

Details

Robotic Intelligence and Automation, vol. 44 no. 2
Type: Research Article
ISSN: 2754-6969

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Article
Publication date: 13 April 2020

Hui Li, Heng Liu, Hao Li, Shemiao Qi, Yi Liu and Fengtao Wang

The purpose of this paper is to investigate the effect of the cage-pocket wear on the dynamic behavior of the ball bearing.

217

Abstract

Purpose

The purpose of this paper is to investigate the effect of the cage-pocket wear on the dynamic behavior of the ball bearing.

Design/methodology/approach

Through analyzing the complicated relationship and interactions among the ball bearing elements, the dynamic modeling of the ball bearing was established considering the gravity, drag force from the oil, hydrodynamic effect on the cage and the dynamic simulations with different amounts of the cage-pocket wear loss of the ball bearing (BPWL) were obtained by solving the ball bearing dynamic equations using Runge–Kutta method.

Findings

The results show that the trajectory of the cage’s centroid presents two vibration modes with different amplitudes. In addition, those two different forms of trajectory of different amplitudes emerge alternatively with BPWL increase moreover the diameter of the trajectory decrease significantly with the BPWL increasing, which is consistent with the experimental result and last BPWL has lightly effect on the average skidding ratio of the cage, however, the BPWL would produce significant effects on the fluctuation of the skidding ratio, which can directly reflect the stability of motion to a certain extent.

Originality/value

Practice shows that the bearing failure resulting from the cage accounts for 25 per cent of the total failure of the rolling bearings. However, few discussions about how the wear of the cage-pocket would influence the dynamic characteristics of the cage. This study can provide important ideas for the design of bearing cage-pocket size and the fault identification of the ball bearing to decrease the failure rate caused by the cage.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0535/

Details

Industrial Lubrication and Tribology, vol. 72 no. 7
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 March 1997

L. Christine Britton, Christine M. Doherty and Derrick F. Ball

The size structure of the executive recruitment consultancy industry is similar to that found in other business service industries in that the industry is predominantly comprised…

328

Abstract

The size structure of the executive recruitment consultancy industry is similar to that found in other business service industries in that the industry is predominantly comprised of small firms. This paper considers the reasons for small firm size in the industry and looks at the implications this has for expansion into Europe. The size structure of the industry is mainly due to the nature of the outcome, the service provision process and the barriers to growth which are a result of the particular client‐consultant relationship. Increased globalization of markets has led to an increase in the amount of international work carried out by executive recruitment consultancies. The larger international consultancies with branches in most European countries are in a strong position to take advantage of this. For the small consultancies wishing to offer international services, the main method adopted is to enter or establish an international network. © 1997 John Wiley & Sons, Ltd. and European Research Press Ltd.

Details

Journal of Small Business and Enterprise Development, vol. 4 no. 3
Type: Research Article
ISSN: 1462-6004

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Book part
Publication date: 17 December 2015

Abstract

Details

Knowing, Becoming, doing as Teacher Educators: Identity, Intimate Scholarship, Inquiry
Type: Book
ISBN: 978-1-78441-140-4

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Book part
Publication date: 17 December 2015

Abstract

Details

Knowing, Becoming, doing as Teacher Educators: Identity, Intimate Scholarship, Inquiry
Type: Book
ISBN: 978-1-78441-140-4

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Book part
Publication date: 17 December 2015

Abstract

Details

Knowing, Becoming, Doing as Teacher Educators: Identity, Intimate Scholarship, Inquiry
Type: Book
ISBN: 978-1-78441-140-4

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Book part
Publication date: 17 December 2015

Abstract

Details

Knowing, Becoming, Doing as Teacher Educators: Identity, Intimate Scholarship, Inquiry
Type: Book
ISBN: 978-1-78441-140-4

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Article
Publication date: 1 April 1988

C.G. Elstone, D.F. Ball and A.W. Pearson

The article looks at one aspect of a study of the R&D/marketing interface in six projects drawn from three companies in the pharmaceutical industry.

496

Abstract

The article looks at one aspect of a study of the R&D/marketing interface in six projects drawn from three companies in the pharmaceutical industry.

Details

Management Research News, vol. 11 no. 4/5
Type: Research Article
ISSN: 0140-9174

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Book part
Publication date: 26 October 2015

Karen Hammerness and Kirsti Klette

In the United States, policy discussions of teacher education in relationship to teacher quality have tended to focus more closely around debates about the nature of teacher…

Abstract

In the United States, policy discussions of teacher education in relationship to teacher quality have tended to focus more closely around debates about the nature of teacher preparation and the need for quality teachers to possess advanced degrees or certification. The field is in need of an array of indicators – a set of powerful, well-researched indicators that can be applied to large public universities as well as small regional private colleges, from university-based programs to “alternative” programs and to more “hybrid” programs. These indicators need to be relevant for teacher certification across a variety of age-ranges and developmental stages. In this chapter, we build on a growing conversation about practice in teacher education and efforts on the part of researchers to identify key features of powerful teacher education. We propose that quality teacher education is designed around a clear and shared vision of good teaching; it is coherent in that it links theory with practice and offers opportunities to learn that are aligned with the vision of good teaching; and it offers opportunities to enact teaching. While these features are supported for the most part by growing consensus in the literature (National Research Council, 2010; NCATE, 2010), there is also an emerging empirical base that provides support for the value of these features as well.

Details

Promoting and Sustaining a Quality Teacher Workforce
Type: Book
ISBN: 978-1-78441-016-2

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Article
Publication date: 1 March 1994

L. Christine Britton and Derrick F. Ball

Examines the characteristics and structure of executive recruitmentconsultancies in France. Search consultants recruit through“head‐hunting” while selection consultants recruit…

1161

Abstract

Examines the characteristics and structure of executive recruitment consultancies in France. Search consultants recruit through “head‐hunting” while selection consultants recruit through advertising. These consultancies play an important part in the market for executive recruitment. The nature of the product has implications for the behaviour of the consultancies and the structure of the industry. There is little or no price competition in the market; instead there is a reliance on non‐traditional non‐price competition. There are two factors which have affected the industry: the recession, which has led to changes in the focus and role of the consultancies; and the creation of the Single European Market, which has led to the increasing internationalization of business.

Details

European Business Review, vol. 94 no. 1
Type: Research Article
ISSN: 0955-534X

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