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Article
Publication date: 5 March 2018

Dhayalan R., Subrahmanyam Saderla and Ajoy Kanti Ghosh

The purpose of this paper is to present the application of the neural-based estimation method, Neural-Gauss-Newton (NGN), using the real flight data of a small unmanned aerial…

469

Abstract

Purpose

The purpose of this paper is to present the application of the neural-based estimation method, Neural-Gauss-Newton (NGN), using the real flight data of a small unmanned aerial vehicle (UAV).

Design/methodology/approach

The UAVs in general are lighter in weight and their flight is usually influenced by the atmospheric winds because of their relatively lower cruise speeds. During the presence of the atmospheric winds, the aerodynamic forces and moments get modified significantly and the accurate mathematical modelling of the same is highly challenging. This modelling inaccuracy during parameter estimation is routinely treated as the process noise. Furthermore, because of the limited dimensions of the small UAVs, the measurements are usually influenced by the disturbances caused by other subsystems. To handle these measurement and process noises, the estimation methods based on neural networks have been found reliable in the manned aircrafts.

Findings

Six sets of compatible longitudinal flight data of the designed UAV have been chosen to estimate the parameters using the NGN method. The consistency in the estimates is verified from the obtained mean and the standard deviation and the same has been validated by the proof-of-match exercise. It is evident from the results that the NGN method was able to perform on a par with the conventional maximum likelihood method.

Originality/value

This is a partial outcome of the research carried out in estimating parameters from the UAVs.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 2
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 1 February 2022

Tandralee Chetia, Dhayalan Rajaram and Kumaran G. Sreejalekshmi

Flapping-wing vehicles show various advantages as compared to fixed wing vehicles, making flapping-wing vehicles' study necessary in the current scenario. The present study aims…

212

Abstract

Purpose

Flapping-wing vehicles show various advantages as compared to fixed wing vehicles, making flapping-wing vehicles' study necessary in the current scenario. The present study aims to provide guidelines for fixing geometric parameters for an initial engineering design by a simple aerodynamic and flight dynamic parametric study.

Design/methodology/approach

A mathematical analysis was performed to understand the aerodynamics and flight dynamics of the micro-air vehicle (MAV). Only the forces due to the flapping wing were considered. The flapping motion was considered to be a combination of the pitching and plunging motion. The geometric parameters of the flapping wing were varied and the aerodynamic forces and power were observed. Attempts were then made to understand the flight stability envelope of the MAV in a forward horizontal motion in the vertical plane with similar parametric studies as those conducted in the case of aerodynamics.

Findings

From the aerodynamic study, insights were obtained regarding the interaction of design parameters with the aerodynamics and feasible ranges of values for the parameters were identified. The flapping wing was found to have neutral static stability. The flight dynamic analysis revealed the presence of an unstable oscillatory mode, a stable fast subsidence mode and a neutral mode, in the forward flight of the MAV. The presence of unstable modes highlighted the need for active control to restore the MAV to equilibrium from its unstable state.

Research limitations/implications

The study does not take into account the effects of control surfaces and tail on the aerodynamics and flight dynamics of the MAV. There is also a need to validate the results obtained in the study through experimental means which shall be taken up in the future.

Practical implications

The parametric study helps us to understand the extent of the impact of the design parameters on the aerodynamics and stability of the MAV. The analysis of both aerodynamics and dynamic stability provides a holistic picture for the initial design. The study incorporates complex mathematical equations and simplifies such to understand the aerodynamics and flight stability of the MAV from an engineering perspective.

Originality/value

The study adds to already existing knowledge on the design procedures of a flapping wing.

Details

International Journal of Intelligent Unmanned Systems, vol. 11 no. 2
Type: Research Article
ISSN: 2049-6427

Keywords

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Article
Publication date: 4 January 2016

Subrahmanyam Saderla, Dhayalan R and Ajoy Kanti Ghosh

The purpose of this paper is to describe the longitudinal aerodynamic characterization of an unmanned cropped delta configuration from real flight data. In order to perform this…

510

Abstract

Purpose

The purpose of this paper is to describe the longitudinal aerodynamic characterization of an unmanned cropped delta configuration from real flight data. In order to perform this task an unmanned configuration with cropped delta planform and rectangular cross-section has been designed, fabricated, instrumented and flight tested at flight laboratory in Indian Institute of Technology Kanpur (IITK), India.

Design/methodology/approach

As a part of flight test program a real flight database, through various maneuvers, have been generated for the designed unmanned configuration. A dedicated flight data acquisition system, capable of onboard logging and telemetry to ground station, has been used to record the flight data during these flight test experiments. In order to identify the systematic errors in the measurements, the generated flight data has been processed through data compatibility check.

Findings

It is observed from the flight path reconstruction that the obtained biases are negligible and the scale factors are almost close to unity. The linear aerodynamic model along with maximum likelihood and least-square methods have been used to perform the parameter estimation from the obtained compatible flight data. The lower values of Cramer-Rao bounds obtained for various parameters has shown significant confidence in the estimated parameters using maximum likelihood method. In order to validate the aerodynamic model used and to increase the confidence in the estimated parameters a proof-of-match exercise has been carried out.

Originality/value

The entire work presented is original and all the experiments have been carried out in Flight laboratory of IITK.

Details

International Journal of Intelligent Unmanned Systems, vol. 4 no. 1
Type: Research Article
ISSN: 2049-6427

Keywords

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Article
Publication date: 3 July 2017

Jun Tu, Tao Chen, Zhi Xiong, Xiaochun Song and Songling Huang

The aim of this paper is to better understand the generation and transmission mechanism of the electromagnetic acoustic transducer (EMAT).

217

Abstract

Purpose

The aim of this paper is to better understand the generation and transmission mechanism of the electromagnetic acoustic transducer (EMAT).

Design/methodology/approach

A semi-analytical method was used to calculate the Lorentz force. Both the hypothetical magnetic field mirror method and the diffusion equation were adopted to solve the eddy current distribution by variables separation method in time domain. A three-dimension magnetostatic finite element model was used to calculate the static magnetic field and the relative permeability. And an experimental platform with a piezoelectric probe to generate and an EMAT to receive, the ultrasonic wave was set up to verify the distribution of the Lorentz force.

Findings

The Lorentz force at different time and in different positions of the steel plate can be easily calculated. The experimental results show a good agreement with the analytical results.

Originality/value

The accurate prediction of the Lorentz force provides an insight into the physical phenomenon of EMAT and a powerful tool to design optimum EMAT.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 1 May 2020

Hari Om Verma and Naba Kumar Peyada

The purpose of this paper is to investigate the estimation methodology with a highly generalized cost-effective single hidden layer neural network.

284

Abstract

Purpose

The purpose of this paper is to investigate the estimation methodology with a highly generalized cost-effective single hidden layer neural network.

Design/methodology/approach

The aerodynamic parameter estimation is a challenging research area of aircraft system identification, which finds various applications such as flight control law design and flight simulators. With the availability of the large database, the data-driven methods have gained attention, which is primarily based on the nonlinear function approximation using artificial neural networks. A novel single hidden layer feed-forward neural network (FFNN) known as extreme learning machine (ELM), which overcomes the issues such as learning rate, number of epochs, local minima, generalization performance and computational cost, as encountered in the conventional gradient learning-based FFNN has been used for the nonlinear modeling of the aerodynamic forces and moments. A mathematical formulation based on the partial differentiation is proposed to estimate the aerodynamic parameters.

Findings

The real flight data of longitudinal and lateral-directional motion have been considered to estimate their respective aerodynamic parameters using the proposed methodology. The efficacy of the estimates is verified with the results obtained through the conventional parameter estimation methods such as the equation-error method and filter-error method.

Originality/value

The present study is an outcome of the research conducted on ELM for the estimation of aerodynamic parameters from the real flight data. The proposed method is capable to estimate the parameters in the presence of noise.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 21 February 2020

Yihui Da, Guirong Dong, Yan Shang, Bin Wang, Dianzi Liu and Zhenghua Qian

Quantitatively detecting surface defects in a circular annulus with high levels of accuracy and efficiency has been paid more attention by researchers. The purpose of this study…

333

Abstract

Purpose

Quantitatively detecting surface defects in a circular annulus with high levels of accuracy and efficiency has been paid more attention by researchers. The purpose of this study is to investigate the theoretical dispersion equations for circumferential guided waves and then develop an efficient technique for accurate reconstruction of defects in pipes.

Design/methodology/approach

The methodology applied to determine defects in pipelines includes four steps. First, the theoretical work is carried out by developing the appropriate dispersion equations for circumferential guided waves in a pipe. In this phase, formulations of strain-displacement relations are derived in a general equidistant surface coordinate. Following that, a semi-analytical finite element method (SAFEM) is applied to solve the dispersion equations. Then, the scattered fields in a circular annulus are calculated using the developed hybrid finite element method and simulation results are in accord with the law of conservation of energy. Finally, the quantitative detection of Fourier transform (QDFT) approach is further enhanced to efficiently reconstruct the defects in the circular annuli, which have been widely used for engineering applications.

Findings

Results obtained from four numerical examples of flaw detection problems demonstrate the correctness of the developed QDFT approach in terms of accuracy and efficiency. Reconstruction of circumferential surface defects using the extended QDFT method can be performed without involving the analytical formulations. Therefore, the streamlined process of inspecting surface defects is well established and this leads to the reduced time in practical engineering tests.

Originality/value

In this paper, the general dispersion equations for circumferential ultrasonic guided waves have been derived using an equidistant surface coordinate and solved by the SAFEM technique to discover the relationship between wavenumber of a wave and its frequency. To reconstruct defects with high levels of accuracy and efficiency, the QDFT approach has been further enhanced to inspect defects in the annular structure.

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Article
Publication date: 15 January 2021

Shivani Agrawal, Vinay Singh and Yogesh Upadhyay

Due to wider acceptance of information technology (IT) and e-commerce among the consumers, firms belonging to agri businesses are rapidly redefining IT-driven stakeholders'…

635

Abstract

Purpose

Due to wider acceptance of information technology (IT) and e-commerce among the consumers, firms belonging to agri businesses are rapidly redefining IT-driven stakeholders' centric completive strategy for their supply chain. This has forced the firms to understand the stakeholders' information needs and quality they expect from the electronic supply chains. Thus, the present study focusses on developing an information quality framework that ensures the success of stakeholders' centric e-agri supply chain. The study also attempts to investigate the interrelationship between formative endogenous latent variables, i.e. value of information (VoI), e-platform responsiveness (RESP), e-platform aesthetics (SAE), e-platform ease of use (EoU) and fulfillment of expectation (FoE) used in the developing the proposed framework.

Design/methodology/approach

Survey based data are obtained from 280 respondents using semistructured questionnaire to validate the proposed theoretical framework. The structural equation modeling is performed using IBM Statistical Product and Service Solutions (SPSS) 16.0 and Analysis of Moment Structures (AMOS) 24.0 package to establish structural model by accommodating determinants of information quality framework identified from extent literature. Confirmatory factor analysis (CFA) is employed to examine the robustness of manifesting variables that define the latent constructs. The robustness measuring items of constructs are also ensured through specified criteria of reliability, convergent validity and discriminant validity. At last the one-way ANOVA and post-hoc analysis are employed to investigate the stakeholders’ group difference on each study construct.

Findings

The results infer the impact RESP, VoI, SAE and EoU on the fulfillment of expectation (FoE). After applying the bootstrapping technique, it was observed that all causal relationships as proposed in hypotheses H1, H1a, H1b, H2, H3 and H4 have gained significant empirical support, thus verify the framework applicable to e-agri supply chain as the study outcome. Addition to this, SAE mediates relationship of RESP and VoI. The RESP and SAE have an indirect positive effect on “EoU.” Findings also suggest that the intermediaries expect better e-platform responsiveness and value of information from e-agri supply chain as compared to farmers and end consumers.

Practical implications

The findings of the study emphasized on the importance of five exogenous variables for e-agri supply chain in order to achieve stakeholders' expectation fulfillment on the information delivered through e-agri supply chain. The study is of great significance to the practitioners and management professionals by aiding strategic worth of market expansion by maximizing users' base by developing, deploying and facilitating a responsive and resilient stakeholders' centric e-agri supply chains. The study provides insights to the cross-domain researchers, firms, managers and policymakers to capture detailed and deeper understanding on the system design, stakeholders' behavior and in policy formulation so as to suggest remedial measures to strengthen the stakeholders' belief on relying e-agri supply chain.

Originality/value

The study considers the empirical model that shows the determinants and their relationship in the “information quality framework” as unique and novel contribution in the context of e-agri supply chain. The framework determines the quality and efficacious use of information that regulates the effectiveness of e-platform from stakeholders' perspective. The investigated constructs and their relationship depict their importance in creating systematic value chain of information across the supply chain.

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