Search results

1 – 10 of over 67000
Article
Publication date: 31 May 2011

Zdobyslaw Goraj and Wojciech Chajec

The purpose of this paper is to find an influence of the reduced stiffness of actuators, located on the most outer parts of ailerons, flaperons, rudders, elevators and elevons on…

Abstract

Purpose

The purpose of this paper is to find an influence of the reduced stiffness of actuators, located on the most outer parts of ailerons, flaperons, rudders, elevators and elevons on the excitation of flutter. This phenomenon is especially important for unmanned aerial vehicles because they continuously use all these control surfaces for trimming and stabilisation and on the other hand, the numerous statistics show that failure of elements of flight control systems are still the most probable reasons of aircraft critical failure.

Design/methodology/approach

Flutter calculations were performed by use of the classical modal approach. The normal vibrations of the free aircraft were measured in the ground vibration test (GVT). Test results were used either for verification of the FEM model of the structure – in this case for flutter calculation the MSC.Nastran software was used, or directly for flutter calculation. Based on the flutter analysis, the control surfaces critical for flutter were determined.

Findings

These so‐called critical control surfaces –, i.e. surfaces responsible for flutter excitation at first – are localized on outer parts of wing and empennage. It was found that the critical surfaces should have been mass balanced or should be irreversible. In the second case, i.e. when the control surfaces are irreversible, the actuators and drivers should have been of a high reliability, because disconnection of these elements could involve flutter.

Research limitations/implications

This approach within the computational analysis is limited to linear case, otherwise NASTRAN software cannot be used for flutter analysis. GVTs could be performed successfully independently if the structure has linear or non‐linear properties.

Practical implications

It was found that before any flight the stiffness in the flight control system of all control surfaces must carefully be checked and kept above the critical stiffness value. Safety level strongly depends on the reliability of actuators used on such unmanned aerial vehicles. The simulation of disconnection (as a result of damage) of selected control surfaces is possible even if the GVT were provided on undamaged vehicle. To do it, the rotational mode of so‐called “free control surface” should be prepared (as an artificial resonant mode) for all deflected control surfaces; next all the resonant modes should be orthogonalized, relative to this artificial control surfaces mode.

Originality/value

This paper was based on two big European and national projects, and all presented results are original and were never published before. Some selected graphs were shown during the EASN Workshop, Paris, September 2010 at the presentation entitled: “Aeroelastic analysis of remotely controlled research vehicles with numerous control surfaces”.

Details

International Journal of Structural Integrity, vol. 2 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

Open Access
Article
Publication date: 6 July 2022

Klara Granheimer, Tina Karrbom Gustavsson and Per Erik Eriksson

Prior research has emphasised the importance of the early phases of construction projects, as well as the difficulties of procuring engineering services – especially due to the…

Abstract

Purpose

Prior research has emphasised the importance of the early phases of construction projects, as well as the difficulties of procuring engineering services – especially due to the uncertainties. Despite that, studies on the public procurement of engineering services are scarce. Although scholars have shown that uncertainty may affect the choice of control modes, the level of uncertainty that characterises services is not addressed by the two task characteristics: knowledge of the transformation process and output measurability. The purpose is to investigate organisational control in public procurement of engineering services.

Design/methodology/approach

The existing control model was adjusted in this study by conceptually adding uncertainty as a third aspect to the two task characteristics. A single case study of the Swedish Transport Administration was used. The empirical data, comprising 14 interviews with managers from the client and engineering consulting companies, were analysed using flexible pattern matching and visual mapping approaches and then illustrated using the model.

Findings

The public client did not base its choice of control modes on uncertainty, but rather on the other two task characteristics. Consequently, the service providers argued that the chosen control modes reduced their creativity, increased their financial risks and caused unclear responsibilities. This study therefore shows that uncertainty is an important factor to consider in the choice of control modes, both from a theoretical perspective and from the service providers' point of view. The developed model may therefore be useful for researchers as well as practitioners.

Originality/value

This study is the first attempt to add uncertainty as a task characteristic when choosing control modes. The results contribute to the scarce control literature regarding the procurement of engineering services for construction projects and the procurement of other services with high uncertainty.

Details

Engineering, Construction and Architectural Management, vol. 31 no. 13
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 23 November 2021

Gangfeng Yan

The purpose of this paper is to achieve high-precision sliding mode control without chattering; the control parameters are easy to adjust, and the entire controller is easy to use…

Abstract

Purpose

The purpose of this paper is to achieve high-precision sliding mode control without chattering; the control parameters are easy to adjust, and the entire controller is easy to use in engineering practice.

Design/methodology/approach

Using double sliding mode surfaces, the gain of the control signal can be adjusted adaptively according to the error signal. A kind of sliding mode controller without chattering is designed and applied to the control of ultrasonic motors.

Findings

The results show that for a position signal with a tracking amplitude of 35 mm, the traditional sliding mode control method has a maximum tracking error of 0.3326 mm under the premise of small chattering; the boundary layer sliding mode control method has a maximum tracking error of 0.3927 mm without chattering, and the maximum tracking error of continuous switching adaptive sliding mode control is 0.1589 mm, and there is no chattering. Under the same control parameters, after adding a load of 0.5 kg, the maximum tracking errors of the traditional sliding mode control method, the boundary layer sliding mode control method and the continuous switching adaptive sliding mode control are 0.4292 mm, 0.5111 mm and 0.1848 mm, respectively.

Originality/value

The proposed method not only switches continuously, but also the amplitude of the switching signal is adaptive, while maintaining the robustness of the conventional sliding mode control method, which has strong engineering application value.

Details

Assembly Automation, vol. 42 no. 1
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 1 March 2006

Anders Blomstermo, D. Deo Sharma and James Sallis

The purpose of this study is to examine the relationship between foreign market entry modes and hard‐ and soft‐service firms. The paper investigated which foreign market entry…

24228

Abstract

Purpose

The purpose of this study is to examine the relationship between foreign market entry modes and hard‐ and soft‐service firms. The paper investigated which foreign market entry modes service firms opt for, and if this is influenced by systematic differences between types of service industries. A secondary purpose is to test the generalizability of the research findings from manufacturing sector to service sector firms.

Design/methodology/approach

Our sample consisted of 140 Swedish service firms. These firms were investigated using a mailed questionnaire survey, and logistic regression analysis was used for testing the hypotheses.

Findings

The statistical analysis shows that, in general, soft‐service firms are much more likely than hard service firms to choose a high control entry mode over a low control entry mode. Furthermore, as cultural distance increases, the likelihood of this choice increases even more.

Research limitations/implications

The implications are that while hard service suppliers can learn from the experience of manufacturing firms going abroad, soft services are unique. Given the importance for soft‐service suppliers to interact with their foreign customers, they should opt for a high degree of control over their foreign market entry mode. In future research on foreign market entry mode selection in service firms more attention should be given to social processes that exercise control.

Originality/value

The findings enhance knowledge on foreign market entry by service firms.

Details

International Marketing Review, vol. 23 no. 2
Type: Research Article
ISSN: 0265-1335

Keywords

Article
Publication date: 11 March 2004

Tao Gao

This paper delves into the mechanism of the contingency framework for foreign entry mode decisions and identifies two essential tasks that jointly determine the outcome of the…

Abstract

This paper delves into the mechanism of the contingency framework for foreign entry mode decisions and identifies two essential tasks that jointly determine the outcome of the entry mode decision. It then recognizes a critical weakness in previous research pertaining to the comparison of entry modes along a key decision criterion, the degree of control. Existing studies generally treat equity involvement as the only source of entrant control, while largely ignoring non‐equity sources of control (i.e., bargaining power and trust). Non‐equity sources of control, when underutilized, amount to missed opportunities, increased resource commitments, and heightened risk exposures in foreign markets. Drawing from a pluralism perspective in transaction and relationship governance, the author presents a more integrative method for the ranking of entry modes along the degree of control. The central message is that companies entering foreign markets should make an earnest effort to identify trust and bargaining power situations and fully utilize their control potential in making entry mode decisions.

Details

Multinational Business Review, vol. 12 no. 1
Type: Research Article
ISSN: 1525-383X

Keywords

Article
Publication date: 12 October 2012

Qu Shao‐cheng, Wang Xiao‐yan and Wang Yong‐ji

The purpose of this paper is to find a practical active sliding mode control approach for synchronization of two uncertain chaotic systems.

Abstract

Purpose

The purpose of this paper is to find a practical active sliding mode control approach for synchronization of two uncertain chaotic systems.

Design/methodology/approach

Sliding mode control approach is known to be an efficient alternative way to implement synchronization for uncertain chaotic systems. However, design of traditional sliding mode controller usually needs complex state transformation. Owing to a novel idea of virtual state feedback, a control strategy for synchronization of uncertain chaotic systems is presented, which does not need any complex state transformation. Furthermore, based on Lyapunov stability theory, a sufficient condition is drawn for the robust stability of the error dynamics of synchronization for uncertain chaotic systems.

Findings

A novel active sliding mode control approach is proposed to achieve the synchronization of two uncertain chaotic systems.

Research limitations/implications

The main limitation is that uncertainties must meet matched conditions.

Practical implications

The paper presents a useful control approach for synchronization of two uncertain chaotic systems.

Originality/value

The proposed sliding mode control approach based on novel virtual state feedback does not need any complex state transformation, unlike the traditional sliding mode control.

Details

Kybernetes, vol. 41 no. 9
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 30 May 2008

David Forlani, Madhavan Parthasarathy and Susan M. Keaveney

The primary purpose of this paper is to investigate how opportunity for control and firm capability interact to moderate the amount of risk that managers associate with various…

7261

Abstract

Purpose

The primary purpose of this paper is to investigate how opportunity for control and firm capability interact to moderate the amount of risk that managers associate with various international entry‐mode strategies. A secondary goal is to investigate how managers perceive the need to retain control over three core functional areas (marketing, production, and R&D) when making entry‐mode decisions.

Design/methodology/approach

A field experiment design was implemented in a sample of US business owner/executives. Using an online data collection method, the study asked a sample of small‐business owners and managers to assess the amount of risk they associated with three modes of entering the Japanese market: non‐ownership (export), equal partnership (50/50 joint‐venture), and sole‐ownership. They were also asked how much control they needed to retain over R&D, production, and marketing for the venture to be successful.

Findings

Ownership‐provided control interacts with capability to influence managerial risk perceptions. Managers in lower‐capability firms see the least risk in the non‐ownership entry mode while those in higher‐capability firms see the least risk in the equal‐partnership entry mode. Managers believe that for a new venture in a foreign market to be successful, control should be retained over the R&D function, regardless of entry mode.

Research limitations/implications

The findings appear to reconcile some of the conflicting predictions of the transaction cost and resource‐based theoretical perspectives, because it appears that international managers consider both control (internationalization theory) and capability (resource‐based theory) when judging the perceived risk of an entry strategy.

Practical implications

For firms that are incapable of managing in an international context, a low‐control no‐ownership entry mode is perceived as the least risky approach; for firms that have some capability for international management, then a partial‐ownership mode such as a 50/50 joint‐venture is perceived as having lower risk than no‐ownership. In non‐ownership and joint‐venture type entry modes, managers are more apt to outsource the marketing function to an agent/partner, but not R&D. In contrast, managers believe that marketing needs to be maintained in‐house when utilizing a sole‐ownership entry mode.

Originality/value

By illustrating the role of perceived risk in foreign‐market entry‐mode decisions and demonstrating how capabilities interact with ownership‐provided control to moderate these perceptions, the paper's findings suggest that managers' risk perceptions may mediate the effects of firm‐specific factors, and thus contributes significantly to both theory and practice.

Details

International Marketing Review, vol. 25 no. 3
Type: Research Article
ISSN: 0265-1335

Keywords

Article
Publication date: 26 August 2014

Peng-xin Wei, Chang-sheng Gao and Wu-xing Jing

The purpose of this paper is to propose a combination bank-to-turn control mode with the single moving mass and reaction jet and design the roll control law for the long-range…

Abstract

Purpose

The purpose of this paper is to propose a combination bank-to-turn control mode with the single moving mass and reaction jet and design the roll control law for the long-range reentry maneuverable warhead.

Design/methodology/approach

Based on the dynamics model of this new control mode, the control model of roll channel is converted into a perturbed double-integrator system. The on-off optimal feedback control law is designed on the phase plane formed by Euler angle error and angular velocity error. To weaken the “on-off chattering” that is generated near the origin of the phase-plane and effectively reduce the jet fuel consumption for stability control, an on-off control outer ring and an inner ring are introduced into the phase plane.

Findings

This control mode can not only avoid the aerodynamic rudder ablation to improve the efficiency of attitude control, but also reduce the fuel consumption of jet control by using moving mass control. The simulation results indicate that the designed control law can meet the speediness and robustness requirements of the long-range maneuverable warhead controlled by the single moving mass and reaction jet. This measure can also eliminate the on-off chattering effectively.

Practical implications

The new control mode solves some engineering problems of long-range reentry maneuverable warhead controlled by only one actuator. The control mode has a promising prospect in engineering practice.

Originality/value

The paper provides a new control mode and a combination control strategy, and designs an effective control law.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 86 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 1 February 2002

Ming‐Tien Tsai and Yung‐Ming Cheng

The purpose of this paper is to study the ownership entry mode decision in the United States made by firms in Taiwan. A total of 398 companies were sampled and included in the…

Abstract

The purpose of this paper is to study the ownership entry mode decision in the United States made by firms in Taiwan. A total of 398 companies were sampled and included in the mail survey, with usable responses received from 105. We find the asset specificity and the strategic investment motivations are the most important decision criteria for the ownership control entry mode choice for Taiwanese manufacturing firms in the United States. When the stronger the U.S. strategic investment motivations and the higher the asset specificity, the higher the likelihood of Taiwanese manufacturing firm's entry through full‐ownership control mode. Finally, in our conclusion, we propose relevant implications for practice and research.

Details

International Journal of Commerce and Management, vol. 12 no. 2
Type: Research Article
ISSN: 1056-9219

Article
Publication date: 13 November 2017

Maria Jell-Ojobor and Josef Windsperger

The governance structure of international franchise firms varies from higher control modes, such as wholly owned subsidiaries and joint venture franchising, to lower control modes

1777

Abstract

Purpose

The governance structure of international franchise firms varies from higher control modes, such as wholly owned subsidiaries and joint venture franchising, to lower control modes, such as area development and master franchising. Based on organizational economics, strategic management, and international business perspectives, the purpose of this paper is to use the case study analysis to empirically evaluate an integrative model on the franchisor’s choice of international governance modes.

Design/methodology/approach

The study applies qualitative methods, such as in-depth case analysis, to investigate a large set of variables that influence the governance structure decision of the international franchise firm. Specifically, it applies a theory-testing case study with two major competitors in the European automotive rental industry, i.e. Europcar and Sixt. Theory-testing case research is justified by the lack of explanatory research due to the complexity of the franchisor-franchisee relationship phenomena, such as the factors that influence the franchisor’s choice of international governance modes. The investigation of the complex governance structure phenomenon requires a holistic analysis.

Findings

The case study shows that environmental, behavioral, transaction-specific, resource-based (system-specific, market-specific, financial resources), and international strategy considerations are important determinants of the governance mode decision of the international franchise firm.

Research limitations/implications

The study responds to the recent call in organizational economics, marketing, strategic management, and international business literature to develop and test a multi-theoretical framework to explain the governance structure of inter-organizational networks, such as franchise networks.

Originality/value

Few previous studies in international franchising have used more than one theoretical perspective to explain the governance structure of the international franchise firm. This study contributes to the theory-testing case study literature by applying a rigorous method of conducting case research. This includes developing a theoretical framework and a systematic research design. A systematic research design requires a holistic analysis by investigating the international franchise governance modes from a variety of theoretical perspectives which are the organizational economics, strategic management, and the strategy-structure perspective.

Details

International Marketing Review, vol. 34 no. 6
Type: Research Article
ISSN: 0265-1335

Keywords

1 – 10 of over 67000