scholarly journals Multivariate Splines-Based Asymmetric Aerodynamic Modeling of Morphing Aircraft

2018 ◽  
Vol 36 (2) ◽  
pp. 211-219
Author(s):  
Xiaowu Xu ◽  
Wei Zhang ◽  
Hao Zhan
Keyword(s):  
Specific Model ◽  
Global Coordinate System ◽  
Model Structure ◽  
Multivariate Splines ◽  
Aerodynamic Parameter ◽  
Final Model ◽  
Morphing Aircraft ◽  
Aerodynamic Modeling ◽  
Aerodynamic Model ◽  
Aerodynamic Parameters

The aerodynamic parameters of morphing aircraft can vary significantly in the morphing process; the aerodynamic data model is complex and high-order nonlinear. This paper presents a new method of aerodynamic modeling of morphing aircraft by using multivariate splines. Firstly, the aerodynamic coefficient model of morphing aircraft based on the multivariate splines model structure is presented. This model can describe symmetric and asymmetric aerodynamic forces. Then, the multivariate simple splines estimation process is introduced in detail and the concrete formulation is deduced. Finally, the final model structure is determined by error analysis, and the aerodynamic parameter polynomial model in the global coordinate system is obtained by coordinate transformation. The results show that this method can accurately describe the aerodynamic model of morphing aircraft during arbitrary symmetric and asymmetric morphing process without predicting the specific model structure of the aerodynamic parameters related to varying process.

Inflight Aerodynamic Parameter Estimation for Fixed Wing Unmanned Aerial Vehicle

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
R. Jaganraj ◽  
R. Velu
Keyword(s):  
Parameter Estimation ◽  
Unmanned Aerial Vehicle ◽  
Aerodynamic Parameter ◽  
Flight Data ◽  
Aerodynamic Model ◽  
Detection And Identification ◽  
Fault Detection And Identification ◽  
Aerial Vehicle ◽  
Frame Work ◽  
Aerodynamic Parameters

This paper presents the frame work for aerodynamic parameter estimation for small fixed wing unmanned aerial vehicle (UAV). The recent development in autopilot hardware for small UAV enables the in-flight data collection of flight characteristics. A methodology is outlined to collect, process and arrive at a conclusion from the in-flight data using commercial flight controller of under 2kg (micro) fixed wing aircraft, ‘VAF01’ for which a Fault Detection and Identification (FDI) system is under development. As a part of the FDI, the linear longitudinal (3 DOF) aerodynamic model is developed and in-flight experimental data is used to estimate the longitudinal aerodynamic parameters. The Flight Path Reconstruction is completed with the acquired parameters from in-flight experiments and results are discussed for further utilization of them.

Dynamic Modeling of an Unmanned Helicopter From Flight Test Data

2011 ◽  
Author(s):  
Guanlin Wang ◽  
Jihong Zhu ◽  
Hui Xia
Keyword(s):  
Minimum Cost ◽  
Flight Test ◽  
Model Parameters ◽  
Model Structure ◽  
Unmanned Helicopter ◽  
Final Model ◽  
Identification Approach ◽  
Model Set ◽  
Partition Method ◽  
Approach Time

Accurately modeling the dynamic characteristics of a helicopter is difficult and time-consuming. This paper presents a new identification approach which applies the modes partition method and structure traversal (MPM/ST) algorithm. The dynamic modes, instead of model parameters of each model structure, are sequentially identified through MPM. The model with the minimum cost function (CF) is chosen from the best model set and is defined as the final model. Real flight tests of an unmanned helicopter are carried out to verify the identification approach. Time- and frequency-domain results of the identified models clearly demonstrate the potential of MPM/ST in modeling such complex systems.

Physical Essence of Stall Phenomena and its WNN-Based Aerodynamic Modeling from Flight Data

2014 ◽  
Vol 602-605 ◽  
pp. 3140-3143
Author(s):  
Xu Sheng Gan ◽  
Xue Qin Tang ◽  
Hai Long Gao
Keyword(s):  
Neural Network ◽  
Wavelet Neural Network ◽  
Flight Data ◽  
Numerical Examples ◽  
Aerodynamic Modeling ◽  
Aerodynamic Model ◽  
Aerodynamic Method ◽  
Physical Essence ◽  
Set Up

To understand the characteristics of aircraft stall for better aerodynamic model, the physical essence of the stall phenomena of aircraft is first introduced, and then a Wavelet Neural Network (WNN) is proposed to set up the stall aerodynamic model. Numerical examples indicates that through the deep cognition of the stall phenomena of aircraft the proposed stall aerodynamic method has a better accuracy than the traditional neural network and is also effective and feasible.

Hybrid Lateral Aerodynamic Modeling Based on WNN and Kernel Principal Components Feature Extraction

2013 ◽  
Vol 763 ◽  
pp. 242-245
Author(s):  
Xu Sheng Gan ◽  
Hao Lin Cui ◽  
Ya Rong Wu ◽  
Yue Bo Meng
Keyword(s):  
Neural Network ◽  
Principal Components ◽  
Model Parameters ◽  
Aerodynamic Modeling ◽  
Aerodynamic Model ◽  
Training Samples ◽  
Components Analysis ◽  
Kernel Principal Components Analysis ◽  
Basic Features ◽  
Better Than

In order to better describe the dynamic characteristics of aircraft through aerodynamic modeling, a Wavelet Neural Network (WNN) aerodynamic modeling method based on Kernel Principal Components Analysis (KPCA) is proposed. Firstly, the training samples are used to execute KPCA for extracting basic features of samples, and then using the extracted basic features, WNN aerodynamic model was established. The simulation result shows that, the modeling ability of the method proposed is better than that of another 3 methods. It can easily determine of model parameters. This enables it to be effective and feasible to establish the aerodynamic modeling for aircraft.

A New Framework for Aerodynamic Model Identification with Multivariate Splines

2013 ◽  
Author(s):  
Coen C. de Visser ◽  
Erik-Jan Van Kampen ◽  
Q Ping Chu ◽  
Jan Albert Mulder
Keyword(s):  
Model Identification ◽  
Multivariate Splines ◽  
Aerodynamic Model ◽  
New Framework

scholarly journals Incremental model breakdown to assess the multi-hypotheses problem

2017 ◽  
Author(s):  
Florian U. Jehn ◽  
Lutz Breuer ◽  
Tobias Houska ◽  
Konrad Bestian ◽  
Philipp Kraft
Keyword(s):  
Model Performance ◽  
Complex Model ◽  
Model Parameters ◽  
Model Structure ◽  
Objective Functions ◽  
Final Model ◽  
Incremental Model ◽  
Model Efficiency ◽  
Improved Model ◽  
Model Structures

Abstract. The ambiguous representation of hydrological processes have led to the formulation of the multiple hypotheses approach in hydrological modelling, which requires new ways of model construction. However, most recent studies focus only on the comparison of predefined model structures or building a model step-by-step. This study tackles the problem the other way around: We start with one complex model structure, which includes all processes deemed to be important for the catchment. Next, we create 13 additional simplified models, where some of the processes from the starting structure are disabled. The performance of those models is evaluated using three objective functions (logarithmic Nash-Sutcliffe, percentage bias and the ratio between root mean square error to the standard deviation of the measured data). Through this incremental breakdown, we identify the most important processes and detect the restraining ones. This procedure allows constructing a more streamlined, subsequent 15th model with improved model performance, less uncertainty and higher model efficiency. We benchmark the original Model 1 with the final Model 15 and find that the incremental model breakdown leads to a structure with good model performance, fewer but more relevant processes and less model parameters.

scholarly journals Trajectory Estimation of Hypersonic Glide Vehicle Based on Analysis of Aerodynamic Performance

2019 ◽  
Vol 37 (6) ◽  
pp. 1102-1110
Author(s):  
Yunpeng Cheng ◽  
Xiaodong Yan ◽  
Feng Cheng
Keyword(s):  
High Speed ◽  
Engineering Calculation ◽  
Aerodynamic Performance ◽  
The State ◽  
Aerodynamic Parameter ◽  
Trajectory Estimation ◽  
Aerodynamic Model ◽  
Proposed Model ◽  
Improve Accuracy ◽  
Nonlinear Aerodynamic

Due to high speed and high maneuverability of hypersonic glide vehicles (HGVs), the state estimation of such targets has always been a research hotspot. In order to improve accuracy of the trajectory estimation, a nonlinear aerodynamic parameter model for target estimation based on aerodynamic performance analysis is proposed. Firstly, the dynamic characteristics of the hypersonic glide vehicle during the hypersonic gliding stage was analyzed. Then, aiming at HTV-2-liked vehicle, the engineering calculation method was used to form the reference aerodynamic model for the target estimation. Secondly, a deviation model described by first-order Markov process was introduced to compensate the uncertainties of the unknown maneuver information from the target. Finally, extended Kalman filter was utilized to estimate the state of the target. The simulation results show that the proposed model is able to improve the accuracy of acceleration estimation for the HTV-2-liked hypersonic gliding vehicles.

Research on Longitudinal Aerodynamics Modeling Method for Aircraft Stall Based on Wavelet Neural Network from Flight Data

2014 ◽  
Vol 602-605 ◽  
pp. 3144-3147
Author(s):  
Xu Sheng Gan ◽  
Hai Long Gao
Keyword(s):  
Neural Network ◽  
Wavelet Neural Network ◽  
Modeling Method ◽  
Flight Data ◽  
Aerodynamic Modeling ◽  
Aerodynamic Model ◽  
Modeling Problem ◽  
Modeling Flow

For the aerodynamic modeling problem from measured flight data for aircraft stall, a WNN aerodynamic modeling method is proposed. According to the aerodynamic modeling flow from flight data for aircraft stall, WNN is introduced to establish the aerodynamic model of aircraft for stall phenomenon. Experiment shows that the method can improve the modeling ability of WNN, and is suitable for actual aerodynamic modeling for aircraft stall.

High-fidelity aerodynamic modeling of an aircraft using OpenFoam – application on the CRJ700

2021 ◽  
pp. 1-22
Author(s):  
M. Segui ◽  
F.R. Abel ◽  
R.M. Botez ◽  
A. Ceruti
Keyword(s):  
Open Source Software ◽  
Absolute Error ◽  
Flight Simulator ◽  
High Fidelity ◽  
Maximum Absolute Error ◽  
Flight Data ◽  
Aerodynamic Modeling ◽  
Aerodynamic Model ◽  
Data Source ◽  
Source Level

Abstract This study is focused on the development of longitudinal aerodynamic models for steady flight conditions. While several commercial solvers are available for this type of work, we seek to evaluate the accuracy of an open source software. This study aims to verify and demonstrate the accuracy of the OpenFoam solver when it is used on basic computers (32–64GB of RAM and eight cores). A new methodology was developed to show how an aerodynamic model of an aircraft could be designed using OpenFoam software. The mesh and the simulations were designed only using OpenFoam utilities, such as blockMesh, snappyHexMesh, simpleFoam and rhoSimpleFoam. For the methodology illustration, the process was applied to the Bombardier CRJ700 aircraft and simulations were performed for its flight envelope, up to M0.79. Forces and moments obtained with the OpenFoam model were compared with an accurate flight data source (level D flight simulator). Excellent results in data agreement were obtained with a maximum absolute error of 0.0026 for the drag coefficient, thus validating a high-fidelity aerodynamic model for the Bombardier CRJ-700 aircraft.

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