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21 – 30 of over 1000
Article
Publication date: 7 September 2015

Mohd Ariffanan Mohd Basri, Abdul Rashid Husain and Kumeresan A. Danapalasingam

The purpose of this paper is to propose a new approach for robust control of an autonomous quadrotor unmanned aerial vehicle (UAV) in automatic take-off, hovering and landing…

Abstract

Purpose

The purpose of this paper is to propose a new approach for robust control of an autonomous quadrotor unmanned aerial vehicle (UAV) in automatic take-off, hovering and landing mission and also to improve the stabilizing performance of the quadrotor with inherent time-varying disturbance.

Design/methodology/approach

First, the dynamic model of the aerial vehicle is mathematically formulated. Then, a combination of a nonlinear backstepping scheme with the intelligent fuzzy system as a new key idea to generate a robust controller is designed for the stabilization and altitude tracking of the vehicle. For the problem of determining the backstepping control parameters, a new heuristic algorithm, namely, Gravitational Search Algorithm has been used.

Findings

The control law design utilizes the backstepping control methodology that uses Lyapunov function which can guarantee the stability of the nominal model system, whereas the intelligent system is used as a compensator to attenuate the effects caused by external disturbances. Simulation results demonstrate that the proposed control scheme can achieve favorable control performances for automatic take-off, hovering and landing mission of quadrotor UAV even in the presence of unknown perturbations.

Originality/value

This paper propose a new robust control design approach which incorporates the backstepping control with fuzzy system for quadrotor UAV with inherent time-varying disturbance. The originality of this work relies on the technique to compensate the disturbances acting on the quadrotor UAV. In this new approach, the fuzzy system is introduced as an auxiliary control effort to compensate the effect of disturbances. Because the proposed control technique has the capability of robustness against disturbance, thus, it is also suitable to be applied for a broad class of uncertain nonlinear systems.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 87 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

Book part
Publication date: 22 July 2004

Kim Hassall

As the land transport task, especially road is expected to increase significantly, by 2015, it would hardly be surprising that many policy makers will look to some form of urban…

Abstract

As the land transport task, especially road is expected to increase significantly, by 2015, it would hardly be surprising that many policy makers will look to some form of urban transport environmental control long before this date. One method is via the introduction of a set of operational environmental hurdles. This is not a new concept. However, this paper proposes a new environmental initiative for urban transport operations. The scheme which is simple for both operators and regulators proposes an effective and meaningful operational rating system which reflects the efforts an operator may go to in their internal fleet environmental policies in purchasing equipment, daily workload planning, waste disposals policies etc.

The three tiered environmental operator performance rating scheme, the E-plus scheme has three levels of operator segmentation. A good basic auditable level of environmental compliance, an E rating, an excellent rating E plus, and an exceptional rating would be an E double plus. Probably no fleets currently in Australia would earn a double plus rating at this time.

Why should there be a road transport operator environmental rating scheme? Firstly as a measurable benchmark for the community and the fleet operators themselves. Secondly and a factor of growing importance is for the customers who are the buyers of freight services. Already customers are specifying in their tender requirements that transport operator environmental competencies and capabilities be listed. This may aid the selection of an operator for a specific task. For example; food sensitive freight handling may require specific food certification scheme adoption such as the HACCP classification system. Similarly an urban courier contract may specify, environmental credentials which sit under an ISO 14000 framework. However, what more specific operator differentiation criteria can be requested by the customer? The E plus system is being designed for this very purpose. In Australia some regulators and teaching centres have begun to take an interest in this transport operator framework.

Details

Logistics Systems for Sustainable Cities
Type: Book
ISBN: 978-0-08-044260-0

Article
Publication date: 4 November 2019

Shuangshuang Li, Xintian Liu, Xiaolan Wang and Yansong Wang

During the running of automobile, the stabilizer bar is frequently subjected to the impact of complex random loads, which is prone to fatigue failure and accident. In regard to…

Abstract

Purpose

During the running of automobile, the stabilizer bar is frequently subjected to the impact of complex random loads, which is prone to fatigue failure and accident. In regard to this, the purpose of this paper is to study and discuss fatigue life of automobile stabilizer bar.

Design/methodology/approach

Durability bench test shows that failure is located at the joint of sleeve and stabilizer bar body. Based on the collection and compilation of micro-strain load spectrum of the stabilizer bar, the strain-life model is studied considering the influence of average stress and maximum stress at failure area. Seven-grade strain-life curves of the stabilizer bar are established. According to the principle of linear damage accumulation, the relationship between fatigue life and damage is discussed, then the fatigue life of stabilizer bar is predicted. Fatigue life evaluation is carried out from three aspects: reliability analysis, static analysis and fatigue life simulation.

Findings

The results show that the reliability of the test sample is 99.9 percent when the confidence is 90 percent and the durability is 1,073 load spectrum cycles; the ratios of predicted and simulated life to design life are 2.77 and 2.30, respectively.

Originality/value

Based on the road load characteristics of automobile stabilizer bar, the method of fatigue life prediction and evaluation is discussed, which provides a basis for the design and development of automobile chassis components.

Details

International Journal of Structural Integrity, vol. 11 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 26 July 2013

Ali Belhocine and Mostefa Bouchetara

The main purpose of this study is to analyse the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase.

Abstract

Purpose

The main purpose of this study is to analyse the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase.

Design/methodology/approach

The simulation strategy is based on computer code ANSYS11. The modeling of transient temperature in the disc is actually used to identify the factor of geometric design of the disc to install the ventilation system in vehicles. The thermal‐structural analysis is then used coupling to determine the deformation and the Von Mises stress established in the disc, the contact pressure distribution in pads.

Findings

The analysis results showed that temperature field and stress field in the process of braking phase were fully coupled.

Originality/value

The results are satisfactory when compared with those of the specialized literature.

Details

International Journal of Clothing Science and Technology, vol. 25 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

Content available
436

Abstract

Details

Aircraft Engineering and Aerospace Technology, vol. 78 no. 3
Type: Research Article
ISSN: 0002-2667

Keywords

Content available
Article
Publication date: 1 March 2006

150

Abstract

Details

Aircraft Engineering and Aerospace Technology, vol. 78 no. 2
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 11 June 2020

Mohd Sabirin Rahmat, Khisbullah Hudha, Zulkiffli Abd Kadir, Noor Hafizah Amer, Muhammad Luqman Hakim Abd Rahman and Shohaimi Abdullah

The objective of this paper is to develop a fast modelling technique for predicting magneto-rheological fluid damper behaviour under impact loading applications.

Abstract

Purpose

The objective of this paper is to develop a fast modelling technique for predicting magneto-rheological fluid damper behaviour under impact loading applications.

Design/methodology/approach

The adaptive neuro-fuzzy inference system (ANFIS) technique was adopted to predict the behaviour of a magneto-rheological fluid (MRF) damper through experimental characterisation data. In this study, an MRF damper manufactured by Lord Corporation was used for characterisation using an impact pendulum test rig. The experimental characterisation was carried out with various impact energies and constant input currents applied to the MRF damper.

Findings

This research provided a fast modelling technique with relatively less error in predicting MRF damper behaviour for the development of control strategies. Accordingly, the ANFIS model was able to predict MRF damper behaviour under impact loading and showed better performance than the modified Bouc–Wen model.

Research limitations/implications

This study only focused on modelling technique for a single type of MRF damper used for impact loading applications. It is possible for other applications, such as cyclic loading, random loadings and system identification, to be studied in future experiments.

Original/Value

Future researchers could apply the ANFIS model as an actuator model for the development of control strategies and analyse the control performance. The model also can be replicated in other industries with minor modifications to suit different needs.

Details

Multidiscipline Modeling in Materials and Structures, vol. 16 no. 6
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 15 December 2020

Francisco Villarreal-Valderrama, Carlos Santana Delgado, Patricia Del Carmen Zambrano-Robledo and Luis Amezquita-Brooks

Reducing fuel consumption of unmanned aerial vehicles (UAVs) during transient operation is a cornerstone to achieve environment-friendly operations. The purpose of this paper is…

Abstract

Purpose

Reducing fuel consumption of unmanned aerial vehicles (UAVs) during transient operation is a cornerstone to achieve environment-friendly operations. The purpose of this paper is to develop a control scheme that improves the fuel economy of a turbojet in its full operating envelope.

Design/methodology/approach

A novel direct-thrust linear quadratic integral (LQI) approach, comprised by an optimal observer/controller satisfying specified performance parameters, is presented. The thrust estimator, based in a Wiener model, is validated with the experimental data of a micro-turbojet. Model uncertainty is characterized by analyzing variations between the identified model and measured data. The resulting uncertainty range is used to verify closed-loop stability with the circle criterion. The proposed controller provides stable responses with the specified performance in the whole operating range, even with after considering plant nonlinearities. Finally, the direct-thrust LQI is compared with a standard thrust controller to assess fuel economy and performance.

Findings

The direct-thrust LQI approach reduced the fuel consumption by 2.1090% in the most realistic scenario. The controllers were also evaluated using the environmental effect parameter (EEP) and transient-thrust-specific fuel consumption (T-TSFC). These novel metrics are proposed to evaluate the environmental impact during transient-thrust operations. The direct-thrust LQI approach has a more efficient fuel consumption according to these metrics. The results also show that isolating the thrust dynamics within the feedback loop has an important impact in fuel economy. Controllers were also evaluated using the EEP and T-TSFC. These novel metrics are proposed to evaluate the environmental impact during transient-thrust operations. The direct-thrust LQI approach has a more efficient fuel consumption according to these metrics. The results also show that isolating the thrust dynamics within the feedback loop has an important impact in fuel economy.

Originality/value

This study shows the design of an effective direct-thrust control approach that minimizes fuel consumption, ensures stable responses for the full operation range, allows isolating the thrust dynamics when designing the controller and is compatible with classical robustness and performance metrics. Finally, the study shows that a simple controller can reduce the fuel consumption of the turbojet during transient operation in scenarios that approximate realistic operating conditions.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 5 February 2018

Fangwei Xie, Erming Ding, Rui Xuan, Xinxing Zhang, Yixian Feng and Jie Zhu

The purpose of this paper is to study the influence rules of geometric parameters on deformation of valve slices.

Abstract

Purpose

The purpose of this paper is to study the influence rules of geometric parameters on deformation of valve slices.

Design/methodology/approach

Based on the theory of flexural deformation of elastic thin slice, differential functions of deformation for both single and multi-slices are given and derived in detail. Furthermore, the effects of geometric dimensions on deformation are analyzed particularly by using Matlab/simulink.

Findings

The results indicated that the deformation decreases with the increment of fixed ring radius ra, slice thickness h, and its number n. Meanwhile, the deformation increases with a rise of slice radius rb, throttle position rk, the radius ratio λ1 and thickness ratio λ2 of slices.

Originality/value

This research can provide some theoretical supports for the parametric and optimal design of adjustable damping shock absorber.

Details

International Journal of Structural Integrity, vol. 9 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 1 June 1986

G.J. DAVIES, D.R. EASTHAM and B.J. EASTWOOD

This paper is concerned with three types of bearing applications:

Abstract

This paper is concerned with three types of bearing applications:

Details

Industrial Lubrication and Tribology, vol. 38 no. 6
Type: Research Article
ISSN: 0036-8792

21 – 30 of over 1000