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AIAA Aviation Forum and Exposition

作者： Zaninotto, Stefano Gauci, Jason Farrugia, Geoffrey Debattista, Johan Univ Malta Inst Aerosp Technol Msida 2080 Msd Malta HandsOn Syst Ltd Mosta 3000 Mst Malta Malta Air Traff Serv Ltd Luqa 4000 Lqa Malta

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

One of the solutions proposed by the aerospace industry to reduce fuel consumption, air pollution and noise at an airport consists of using electric tow trucks to tow aircraft from the gate to the runway (or vice-versa). However, the introduction of tow trucks would result in an increase in vehicle traffic at the airport, potentially increasing the workload of Air Traffic Controllers (ATC). This paper proposes an algorithm - based on Dijkstra's algorithm - and a Human Machine Interface (HMI) concept to optimise airport taxi operations with autonomous tow trucks at a strategic level, while keeping ATC in the loop. Preliminary tests of the algorithm have been carried out using simulated traffic data for Malta International Airport (MIA) and the results show that the algorithm can be tuned to minimise the average vehicle taxi delay or the number of unresolved vehicle conflicts. It is also shown that, in certain cases, both the taxi delay and the number of conflicts can be reduced through a minor adjustment of the Off-Block Time (OBT) of departing aircraft.

关键词： Commercial Aircraft Human In The Loop Runway Holding Position Shortest Path algorithms Air Traffic Controller Aerospace Industry Fuel Consumption Aircraft Hangars optimization algorithm Aircraft Stand

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An Aerodynamic Design Method of Propeller Airfoils with Geometric Compatibility as Constraints

An Aerodynamic Design Method of Propeller Airfoils with Geom...

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AIAA Aviation Forum and Exposition

作者： Xu, Jian-Hua Li, Hui-Jing Song, Wen-Ping Han, Zhong-Hua Northwestern Polytech Univ Natl Key Lab Sci & Technol Aerodynam Design & Res Xian 710072 Peoples R China Northwestern Polytech Univ Sch Aeronaut POB 754Youyi West Rd 127 Xian Peoples R China

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

The Mach number and Reynolds number vary widely from root to tip for a propeller blade, resulting complex flow at low-speed, subsonic and even transonic. Low-speed airfoils are used for inboard and high-speed airfoils are used for outboard, leading to a great challenge to ensure the aerodynamic compatibility and geometric compatibility of the airfoils under different design conditions. In this paper, some constraints, such as the locations of maximum thickness, coordinates of airfoils with adjacent thickness, and second-order derivative distribution of airfoil shape, are applied in the design optimization of propeller airfoil family, to achieve good geometric compatibility among airfoils. Reynolds-average Navier-Stokes (RANS) solver coupled with gamma-(Re) over bar (theta) transition model and the efficient optimizer "SurroOpt" are used to perform the optimization. The results show that the optimized airfoils with second-order derivative as constraints behave the best geometric compatibility, and the lift-to-drag ratio at the design condition is also improved significantly, which demonstrates that the proposed method is effective in the design of airfoil family for propeller.

关键词： Aerodynamic Force Coefficients Propeller Blades Thin Airfoil Aerodynamic Performance Lift to Drag Ratio Friction Drag Mathematical Models optimization algorithm Genetic algorithm Aeronautics

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A Coupled Newton-Krylov Time Spectral Solver for Wing Flutter and LCO Prediction

A Coupled Newton-Krylov Time Spectral Solver for Wing Flutte...

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AIAA Aviation Forum and Exposition

作者： He, Sicheng Jonsson, Eirikur Mader, Charles A. Martins, Joaquim R. R. A. Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

Flutter onset characteristic is an important consideration for transport aircraft design. Previous work with high fidelity aerostructural optimization has shown a tendency fora* optimization algorithms to produce unrealistically high aspect ratio designs, particularly when maximizing range or minimizing fuel burn, in an effort to maximize aerodynamic efficiency. In this work, we propose an efficient high fidelity flutter solution method. The flow and the structural dynamics have been modeled with time-spectral (TS) method. The TS method is designed to capture the dominant modes of periodic behaviors efficiently. We develop a coupled Newton-Krylov solver to solve this motion-fluid-structure coupled problem. In the literature, Newton-based TS flutter methods have been proposed in a segregated form. In the current work, the whole coupled system is directly solved. By doing so, one motion-fluid-structure solution is required instead of O(N-CSD)xO(N-iter) CFD solutions where N-CSD is the structural degree-of-freedom for all time instances and N-iter is the number of Newton steps. We demonstrate the method on the classic AGARD 445.6 case.

关键词： Structural Dynamics High Aspect Ratio optimization algorithm Aerodynamic Efficiency Transport Aircraft Aerodynamic Design Reynolds Averaged Navier Stokes Euler Equations Newton Raphson Method Flight Envelope

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Aircraft Vertical Route optimization by Beam Search and Initial Search Space Reduction

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JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2018年第3期15卷 157-171页

作者： Murrieta-Mendoza, Alejandro Ternisien, Laurane Beuze, Bruce Botez, Ruxandra Mihaela Super Technol Sch Res Lab Act Controls Av & Aeroservoelast 1100 Notre Dame West Montreal PQ H3C 1K3 Canada

This paper describes ana* optimization algorithm that provides an economical vertical navigation profile by finding the combinations of climb, cruise, and descent speeds, as well as altitudes, for an aircraft to minimize flight costs. The computational algorithm takes advantage of a space search reduction methodology to reduce the initial number of available speed and altitude combinations. The optimal solution was found by implementing the beam search algorithm. A bounding function that correctly estimates the flight cost by considering step climbs was developed to reduce the number of calculations required by the beam search algorithm. The full-flight fuel burn cost was obtained using a performance database-based method. The algorithm uses a numerical performance model instead of equations of motion to compute fuel burn. The database was developed by using flight experimental data. To validate the algorithm, its results were compared to those of three other algorithms: an exhaustive search, beam search, and search space reduction. The solution provided by the algorithm was also compared to the solution provided by a flight management system. Following this comparison, the algorithm systematically found the optimal solutions, which were better in terms of flight cost than those provided by the flight management system.

关键词： Commercial Aircraft FMS optimization algorithm Beam Search algorithm Vertical Navigation Mach Numbers Air Traffic Flow Management Search algorithm Fuel Consumption Flight Trajectory

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Gaussian Mixture Penalty for Trajectory optimization Problems

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2019年第8期42卷 1857-1862页

作者： Rommel, Cedric Bonnans, Frederic Martinon, Pierre Gregorutti, Baptiste Polytech Sch CMAP F-91128 Palaiseau France INRIA F-91120 Palaiseau France Safety Line F-75015 Paris France Polytech Sch CMAP Team Commands F-91128 Palaiseau France

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Stochastic optimization of Nonlinear Energy Sinks for the Mitigation of Limit Cycle Oscillations

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AIAA JOURNAL 2019年第5期57卷 2134-2144页

作者： Pidaparthi, Bharath Missoum, Samy Univ Arizona Aerosp & Mech Engn Tucson AZ 85721 USA

This paper investigates the mitigation of limit cycle oscillations (LCOs) using optimally designed nonlinear energy sinks (NESs). The study is based on an NES attached to a two-degree-of-freedom airfoil with nonlinear stiffness in pitch and heave. Depending on the nonlinear properties of the airfoil, it can exhibit super-or subcritical LCOs. The design of the NES is based on a stochastic optimization approach, which accounts for various sources of uncertainties, including initial and loading conditions. The optimization approach is also tailored to handle potential discontinuities in the response of the airfoil. The non-smoothness of the response can be either due to subcritical LCOs or due to the activation of the NES. Several stochastic optimization problems with the objective of maximizing the mean reduction of LCOs are presented.

关键词： Stochastic optimization Airfoil Probability Density Functions Free Stream Velocity Particle Swarm optimization Damping Coefficient Support Vector Machine Phase Diagram optimization algorithm High Aspect Ratio

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A Multidisciplinary Airplane Research Integrated Library With Applications To Partial Turboelectric Propulsion

A Multidisciplinary Airplane Research Integrated Library Wit...

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AIAA Aviation Forum and Exposition

作者： Druot, T. Belleville, M. Roches, P. Gallard, F. Peteilh, N. Gazaix, A. Ecole Natl Aviat Civile Air Transport Dept Toulouse France Airbus Operat SAS Toulouse France Airbus Operat SAS Future Project Off Toulouse France Inst Technol IRT St Exupery Syst Engn & Modeling Dept Toulouse France

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

The aim of this paper is to present a new model library developped as a new test case to benchmarka* optimization algorithms and Multidisciplinary Design optimization (MDO) formulations. It introduces the MARILib software (Multidisciplinary Airplane Research Integrated Library). MARILib's first objective is to provide models for research on a wide range of aircraft concepts, from business jets to super jumbos, and also some unconventional configurations, through an Overall Aircraft Design (OAD) approach. The second objective is to share a new benchmark test case for MDO strategies, which does not raise intellectual property issues. The third objective is to describe a case study for educational and training purposes. MARILib will be available as Open Source.

关键词： Aeroplane Turboelectric Propulsion Multidisciplinary Design optimization Aircraft Design Business Jet optimization algorithm Intellectual Property Landing Gear Turbofan Engines Aerodynamic Coefficients

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Design of Two-Dimensional Non-uniform Constellations with Better Performance

Design of Two-Dimensional Non-uniform Constellations with Be...

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IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB)

作者： Cai, Yang Zhang, Genning Xu, Yin Hong, Hanjiang He, Dazhi Zhang, Wenjun Shanghai Jiao Tong Univ Cooperat Media Network Innovat Ctr CMIC Sch Elect Informat & Elect Engn Shanghai Peoples R China

ISBN: (纸本)9781728121505

Modern communication systems adopt non-uniform constellations (NUCs) to approach Shannon limit. Generally, the design process of NUCs is based on maximizing bit-interleaved coded modulation (BICM) capacity for given channel conditions. However, the traditional Monte Carlo methods for computing BICM capacity cannot ensure the accuracy of NUC optimization with low complexity. This paper proposes a new design method including the derivation of a computable expression about BICM capacity and a new optimization scheme with simplified calculation of gradient in the algorithm. In this way, we obtain a set of 2D-NUCs with low complexity and better performance than those adopted by ATSC 3M.

关键词： 2D-NUCs BICM capacity optimization algorithm ATSC 3.0

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A COMPLEX-VALUED CONVOLUTIONAL NEURAL NETWORK WITH DIFFERENT ACTIVATION FUNCTIONS IN POLARIMETRIC SAR IMAGE CLASSIFICATION

A COMPLEX-VALUED CONVOLUTIONAL NEURAL NETWORK WITH DIFFERENT...

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International Radar Conference (RADAR)

作者： Zhang, Yun Hua, Qinglong Xu, Dan Li, Hongbo Mu, HuiLin Harbin Inst Technol Sch Elect Informat Engn Harbin Peoples R China

ISBN: (纸本)9781728126609

It is well known that the activation function and the gradient descenta* optimization algorithm have a great influence on convolutional neural network (CNN). Based on the Adama* optimization algorithm, this paper proposes a CvAdama* optimization algorithm suitable for complex-valued convolutional neural network (CV-CNN), and then in the typical polarization SAR image classification task, Adam and CvAdam were compared using four different activation functions of sigmoid, tanh, Leakey-ReLU and ELU. Experiments on the benchmark dataset of Oberpfaffenhofen show that CvAdam performs better than Adam in both convergence speed and accuracy, no matter which activation function is used.

关键词： Complex-valued convolutional neural network (CV-CNN) optimization algorithm activation function synthetic aperture radar (SAR) terrain classification deep learning

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Bayesian Surrogate Modeling of Bladed Disk Sector Mode Shape and Geometrical Spatial Variations

Bayesian Surrogate Modeling of Bladed Disk Sector Mode Shape...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Beck, Joseph A. Brown, Jeffrey M. Kaszynski, Alex A. Carper, Emily B. Air Force Res Lab Wright Patterson AFB OH 45433 USA Aerosp Syst Directorate Turbine Engine Div Wright Patterson AFB OH 45433 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

This effort focuses on the development of a surrogate modeling methodology for predicting Integrally Bladed Rotor sector spatial data. Given two sets of spatially varying data, i.e. mode shape and surface geometries, a method is proposed to predict one set of data given the other set. Predicting mode shape variations caused by geometry perturbations from the nominal design via an efficient surrogate is needed for efficient and accurate Reduced Order Model formulations. Furthermore, predicting geometry variations from mode shape deviations provides a method to create digital representations of structural components. Traditional surrogate modeling approaches typically fall short for spatial data due to the large dimensionality of the inputs and outputs, where each typically numbers in the thousands. To overcome this, a latent variable modeling approach is taken to identify spatial variables that are not directly observable in the original data set. These latent variables are often much smaller in number than the original data dimensions and are capable of providing an input-to-output mapping. Particularly, this surrogate is developed from a Bayesian Canonical Correlation Analysis formulation that augments the limited sample sizes with prior distributions for model parameters. A shared latent variable space between the geometric and modal variations is identified, in addition to latent variable spaces unique to each data set. Furthermore, this modeling approach is capable of predicting geometry variations from a subset of mode shape deviations that may be identified during modal testing. Results indicate the developed Bayesian surrogate is capable of providing accurate spatial predictions of mode shape and geometrical variations, as well as quantifying their associated uncertainty.

关键词： Surrogate Model Finite Element Modeling Air Force Research Laboratory Material Properties Machine Learning Gamma Distribution optimization algorithm High Cycle Fatigue Bayesian Approach Energy Transfer

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