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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 124 journals)
Showing 1 - 30 of 30 Journals sorted by number of followers
AIAA Journal     Hybrid Journal   (Followers: 1002)
SpaceNews     Free   (Followers: 778)
Journal of Spacecraft and Rockets     Hybrid Journal   (Followers: 702)
Journal of Propulsion and Power     Hybrid Journal   (Followers: 569)
Aviation Week     Full-text available via subscription   (Followers: 410)
Aerospace Science and Technology     Hybrid Journal   (Followers: 305)
Advances in Space Research     Hybrid Journal   (Followers: 295)
IEEE Transactions on Aerospace and Electronic Systems     Hybrid Journal   (Followers: 281)
Journal of Aircraft     Hybrid Journal   (Followers: 262)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 251)
Control Systems     Hybrid Journal   (Followers: 235)
Acta Astronautica     Hybrid Journal   (Followers: 220)
Gyroscopy and Navigation     Hybrid Journal   (Followers: 177)
Journal of Navigation     Hybrid Journal   (Followers: 176)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 165)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 139)
Space Science International     Open Access   (Followers: 117)
Space Science Reviews     Hybrid Journal   (Followers: 92)
Propulsion and Power Research     Open Access   (Followers: 89)
International Journal of Aerospace Engineering     Open Access   (Followers: 86)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 82)
Advances in Aerospace Engineering     Open Access   (Followers: 74)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 66)
Aerospace     Open Access   (Followers: 64)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 57)
Space Safety Magazine     Free   (Followers: 50)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 46)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 43)
Space Research Today     Full-text available via subscription   (Followers: 43)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 42)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 37)
International Journal of Aerospace Sciences     Open Access   (Followers: 36)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 31)
Space Policy     Hybrid Journal   (Followers: 30)
Journal of Space Weather and Space Climate     Open Access   (Followers: 30)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 30)
Journal of Aerodynamics     Open Access   (Followers: 27)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 27)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 25)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 23)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 23)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 23)
Aerospace Medicine and Human Performance     Full-text available via subscription   (Followers: 22)
International Journal of Aerospace Psychology     Hybrid Journal   (Followers: 22)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 22)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 21)
Artificial Satellites     Open Access   (Followers: 21)
Fatigue of Aircraft Structures     Open Access   (Followers: 21)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 20)
Frontiers in Aerospace Engineering     Open Access   (Followers: 20)
International Journal of Space Structures     Full-text available via subscription   (Followers: 19)
Nonlinear Dynamics     Hybrid Journal   (Followers: 19)
Chinese Journal of Aeronautics     Open Access   (Followers: 19)
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 16)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 15)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 15)
Journal of Aircraft and Spacecraft Technology     Open Access   (Followers: 15)
Advances in Aerospace Science and Technology     Open Access   (Followers: 14)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 13)
Aviation     Open Access   (Followers: 12)
International Journal of Micro Air Vehicles     Open Access   (Followers: 11)
Journal of Airline and Airport Management     Open Access   (Followers: 11)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 11)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 11)
Population Space and Place     Hybrid Journal   (Followers: 10)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 10)
Journal of Aeronautical Materials     Open Access   (Followers: 10)
Aerospace Systems     Hybrid Journal   (Followers: 10)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 10)
Journal of Aerospace Technology and Management     Open Access   (Followers: 10)
Aeronautical Journal, The     Hybrid Journal   (Followers: 9)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 9)
International Journal of Aviation, Aeronautics, and Aerospace     Open Access   (Followers: 9)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 8)
Journal of Space Safety Engineering     Hybrid Journal   (Followers: 8)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 7)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 7)
Aerospace technic and technology     Open Access   (Followers: 7)
Aviation in Focus - Journal of Aeronautical Sciences     Open Access   (Followers: 7)
New Space     Hybrid Journal   (Followers: 6)
Space and Polity     Hybrid Journal   (Followers: 6)
Aerotecnica Missili & Spazio : Journal of Aerospace Science, Technologies & Systems     Hybrid Journal   (Followers: 6)
Civil Aviation High Technologies     Open Access   (Followers: 6)
Air Medical Journal     Hybrid Journal   (Followers: 6)
REACH - Reviews in Human Space Exploration     Full-text available via subscription   (Followers: 5)
RocketSTEM     Free   (Followers: 5)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 5)
Journal of Astrobiology & Outreach     Open Access   (Followers: 5)
Life Sciences in Space Research     Hybrid Journal   (Followers: 5)
International Journal of Aviation Management     Hybrid Journal   (Followers: 5)
Cosmic Research     Hybrid Journal   (Followers: 5)
Journal of Spatial Science     Hybrid Journal   (Followers: 4)
Journal of KONBiN     Open Access   (Followers: 4)
Astrodynamics     Hybrid Journal   (Followers: 4)
International Journal of Aeronautical and Space Sciences     Hybrid Journal   (Followers: 4)
Unmanned Systems     Hybrid Journal   (Followers: 4)
Transport and Aerospace Engineering     Open Access   (Followers: 4)
Open Aerospace Engineering Journal     Open Access   (Followers: 4)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access   (Followers: 3)
Microgravity Science and Technology     Hybrid Journal   (Followers: 3)
Journal of the Australasian Society of Aerospace Medicine     Open Access   (Followers: 3)
npj Microgravity     Open Access   (Followers: 3)
ASTRA Proceedings     Open Access   (Followers: 3)
MAD - Magazine of Aviation Development     Open Access   (Followers: 3)
Ciencia y Poder Aéreo     Open Access   (Followers: 3)
Journal of Aviation/Aerospace Education & Research     Open Access   (Followers: 2)
Advances in Astronautics Science and Technology     Hybrid Journal   (Followers: 2)
Journal of Engineering and Technological Sciences     Open Access   (Followers: 2)
IEEE Journal on Miniaturization for Air and Space Systems     Hybrid Journal   (Followers: 2)
Perspectives of Earth and Space Scientists i     Open Access   (Followers: 1)
Investigación Pecuaria     Open Access   (Followers: 1)
Transactions on Aerospace Research     Open Access   (Followers: 1)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 1)
Science and Education : Scientific Publication of BMSTU     Open Access   (Followers: 1)
Spatial Information Research     Hybrid Journal   (Followers: 1)
Xibei Gongye Daxue Xuebao / Journal of Northwestern Polytechnical University     Open Access  
Mekanika : Jurnal Teknik Mesin i     Open Access  

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Journal Cover
International Journal of Aeronautical and Space Sciences
Number of Followers: 4  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2093-274X - ISSN (Online) 2093-2480
Published by Springer-Verlag Homepage  [2469 journals]
  • Review of More Electric Engines for Civil Aircraft

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      Abstract: More electric engines (MEEs) and more electric aircraft are mainly implemented to address the global warming issue and make engines more fuel efficient. Developing technology has made them applicable. This paper presents a detailed introduction to the MEE for civil aircraft, including its architecture, characteristics and performance, as well as the potential benefits of fuel consumption and emissions reduction. It is obvious that the adoption of electric components, such as active magnet bearings, electric starters and generators and electric fuel pumps, is beneficial. It is especially advantageous when mechanical, hydraulic and pneumatic systems with great weight and complex structures are eliminated. Moreover, the exploration of electric propulsion systems indicates that the potential profits are large and tempting. The challenges and technology bottlenecks for MEEs are also discussed. With the further development of battery and motor technology, the MEE will undoubtedly play a dominant role in the civil aircraft market.
      PubDate: 2022-05-12
       
  • Optimal Guidance Law for Impact Angle and Acceleration Constraints with
           Time-Varying Gains

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      Abstract: In this paper, we establish an optimal guidance law for impact angle and acceleration constraints (OGL-IAAC). The optimal guidance law for impact angle (OGL) is widely used due to its energy optimality and analytic solutions. However, acceleration constraints may degrade the performance of the OGL owing to the significant guidance command at the initial and terminal time and hence saturated acceleration values may generate guidance errors. We introduce a new weighting function based on the guidance command closed-form solution of the OGL to address this problem. Then, we derive a new guidance law by using Schwarz’s inequality. The proposed guidance law generates time-varying gains to ensure that the guidance command is within the acceleration constraint. Moreover, the gains converge to the same values as those of the OGL when the time-to-go approaches zero. The proposed guidance law is demonstrated by simulations to investigate the performance and effect of varying coefficients of the weighting function.
      PubDate: 2022-05-06
       
  • FOPID Control of Quadrotor Based on Neural Networks Optimization and Path
           Planning Through Machine Learning and PSO Algorithm

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      Abstract: Abstract In this paper, control of the nonlinear dynamics of quadrotor with the help of FOPID controllers was focused, moreover, this literature used neural networks method is used for tuning of the controller. In the next section, finding the optimal path which satisfies the constraints of speed and guarantees the safety and feasibility of the trajectory has been studied. For path planning, machine learning algorithm based on neural networks is used to emulate the controlled plant to raise the computational efficiency. For optimizing the path particle swarm optimization algorithm is considered. The results show the accurate and appropriate performance of the mentioned algorithm.
      PubDate: 2022-05-05
       
  • Integrated Optimal Guidance for Reentry and Landing of a Rocket Using
           Multi-Phase Pseudo-Spectral Convex Optimization

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      Abstract: Abstract This paper proposes integrated optimal guidance for the reentry and landing of a rocket using the multi-phase pseudo-spectral convex optimization method. For a successful return of the launch vehicle, it is crucial to generate the onboard real-time trajectory of the rocket from stage separation to landing, considering vehicle/ground safety and precision landing. Recently, improved computation capability enables online trajectory optimization in real time, especially using the convex optimization method. This paper formulates a multi-phase optimal control problem involving the reentry and landing phases. Then, the original problem is converted to a convex optimization problem based on pseudo-spectral discretization and successive convexification. A case study on the reentry/landing guidance of an actual reusable launch vehicle is conducted to demonstrate the effectiveness of the proposed procedure.
      PubDate: 2022-05-04
       
  • Ascent Guidance Trajectory Optimization Using Evolutionary Algorithm
           Considering Engine Gimbal and Aerodynamic Control

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      Abstract: Abstract To achieve high-range capability, reusability, and aircraft-like operability in spaceplanes, the latter have been investigated actively. One of the critical technologies for spaceplanes is the flexible guidance methodology, which can accommodate various mission requirements and constraints. The application of an evolutionary algorithm to the real-time optimization of longitudinal ascent guidance trajectories is presented herein. The combination of the engine gimbal and aerodynamic control surfaces is considered to improve the design flexibility of the trajectories and mitigate the elevator hinge moment. The range of guidance commands for the engine gimbal angle and the angle of attack that satisfy the longitudinal trim condition are identified in advance and stored as tabular data. The performance of the proposed guidance algorithm is evaluated via a flight simulation of a subscale flight demonstrator.
      PubDate: 2022-05-04
       
  • Design and Analysis of Micro-Vibration Isolation System for Digital Image
           Correlation System-Based Structural Health Monitoring

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      Abstract: Abstract Monitoring and analyzing the conditions of aging aerospace or civil structures such as aircrafts, bridges, and buildings are essential to verify structural integrity. The assessment of structural properties and dynamic characteristics of such systems are important to ensure long-term reliability and to determine the right time for component repair or replacement. Recently, improvement in camera technology and image-processing algorithms has made advanced non-contact full-field measurement techniques, such as the digital image correlation method, appealing for non-destructive evaluation and structural health monitoring. With increasing demands for better image quality and noise reduction from external sources, the stability requirements of camera systems for capturing are becoming more rigorous. To reduce the influence of camera micro-vibration on image quality, vibration isolation of the whole camera system must be considered. Therefore, a method to design and optimize a vibration isolation system needs to be developed. This study presents the engineering analysis and testing of a low-cost vibration isolator specifically aimed at vertical high-frequency motion. The device works on the principle of displacement transmissibility reduction by the use of a wave spring and specially designed brackets. The base features a threaded aperture to allow leveling adjustment of the platform. The isolator is fixed on an electromechanical shaker and excited by a swept-sine signal from 0 to 100 Hz with a small sweep rate. We measured the vibration of isolator by two laser sensors to obtain the transmissibility curve during its operation. As a result, the isolator filters out a broad band of input vibration frequencies and ensures a constant level of vibration transmission reduction in the vertical direction. The isolator features a 10 Hz vertical resonance frequency and begins isolating at 13 Hz. The proposed model is stable and performs sufficiently to eliminate 90% of vibration noise, which satisfies the requirement for a high-speed camera system on the ground.
      PubDate: 2022-04-28
       
  • Coking Test Using Jet A-1 and Desulfurized Kerosene in a Regenerative
           Cooling Channel Environment

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      Abstract: Abstract The walls of a liquid propellant rocket engine generally employ regenerative cooling channels to reduce the enormous heat load generated by the combustion of the fuel and oxidizer. When a hydrocarbon fuel is heated to a high temperature in such an engine, the reaction between the copper in the cooling channel wall and the sulfur in the fuel forms coking material with a high carbon content and low heat transfer coefficient. In this study, a series of coking tests was, therefore, performed using Jet A-1 aviation kerosene and low-sulfur/low-aromatics kerosene in specimens simulating a regenerative cooling channel under various conditions. The coking material remaining inside each specimen was analyzed and photographed using an energy-dispersive X-ray analyzer and a field emission scanning electron microscope. The results were used to determine the relationship between fuel characteristics and coking and its effects on regenerative cooling channel performance.
      PubDate: 2022-04-28
       
  • Estimation of Effective Mechanical Properties of Plain Woven Composites
           Using Direction-Selective Micromechanical Models

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      Abstract: Abstract The directional elastic properties of composite yarn calculated by micromechanical models depend on the type of the models directionally adopted, and which significantly impacts the estimation of effective mechanical properties of woven composites composed of yarns and matrix (resin). This study proposed a methodology to predict the effective mechanical properties of a plain woven composite with lower errors by adopting direction-selective micromechanical models for composite yarns. We found that most of the effective mechanical properties of the plain woven composite are improved. Moreover, the elastic moduli in the warp and fill directions, which critically affect the mechanical behavior of composite structures, are particularly consistent with the experimental data, and exhibit relative errors of 0.18% and 1.93%, respectively. These errors are 95.6% and 16.8% lower than those presented by previous researchers. These findings indicate that the proposed methodology can successfully predict the effective mechanical properties of plain woven composites and contribute to the accurate and efficient analysis of their structural behaviors.
      PubDate: 2022-04-25
       
  • A Novel Fixed-Time Convergence Three-Dimensional Guidance Law for
           Intercepting Highly Maneuvering Targets

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      Abstract: Abstract In this paper, a novel three-dimensional fixed-time convergence guidance law for intercepting highly maneuvering targets is proposed. It comprehensively considers the impact angle constraint, guidance command input saturation constraint, and autopilot second-order dynamics. The guidance law is firstly designed based on a novel fixed-time convergent sliding mode surface proposed in this paper. Then, a backstepping control method is adopted for consideration of autopilot second-order dynamics. By constructing an adaptive auxiliary system, the problem of guidance command input saturation is solved. Additionally, the fixed-time convergence disturbance observer is used to estimate the guidance system disturbance. Using the Lyapunov theory, the stability and fixed-time convergence of the proposed guidance law are proved and analyzed. Finally, the simulation comparison of four different guidance laws shows the excellent guidance performance of the proposed guidance law.
      PubDate: 2022-04-23
       
  • Prediction and Analysis of Transitional Crossflows Using $$\gamma -
           {\text{Re}}_{\theta t} - {\text{CF}}^{ + }$$ γ - Re θ t - CF + Model

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      Abstract: Abstract In the present study, numerical assessment of the \(\gamma - {\text{Re}}_{\theta t} - {\text{CF}}^{ + }\) transition model was carried out using a Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) flow solver based on unstructured meshes. A three-dimensional bump-in-channel verification case was first tested in a fully turbulent manner to verify the implementation of the \(k - {\upomega }\) shear stress transport turbulence model, which was coupled with the laminar-turbulent transition model. In addition, to validate the \(\gamma - {\text{Re}}_{\theta t} - {\text{CF}}^{ + }\) transition model, transition onset locations were compared with the experimental results for three angles-of-attack with a 6:1 prolate spheroid configuration. Then, the \(\gamma - {\text{Re}}_{\theta t} - {\text{CF}}^{ + }\) transition model was utilized to predict the skin friction distributions, surface pressure distributions, and transition onset locations of the natural-laminar-flow version of the common research model (CRM-NLF). For this purpose, a grid-resolution study was carried out for a fixed angle-of-attack on coarse, medium, and fine meshes. The aerodynamic performance of the CRM-NFL was compared with the experimental for four angles of attack.
      PubDate: 2022-04-22
       
  • Numerical Investigation of Wing–Multiple Propeller Aerodynamic
           Interaction Using Actuator Disk Method

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      Abstract: Abstract This study examines the aerodynamic performances of a wing and multiple propellers through a parametric analysis of wing–propeller interactions. A flow analysis was conducted via simulations based on actuator disk method. The parameters analyzed included the number of propellers, rotating direction, and propeller interval. An increment in the number of propellers increased the wing lift and drag, in addition to the propeller thrust and power. Although the lift-to-drag ratio decreased, the ratio of the wing lift to the propeller power increased. The lift and lift-to-drag ratio of the co-rotating systems were larger than those of the counter rotating systems; however, the lift-to-drag ratio of the latter exceeded that of the former when the number of propellers was seven. An increment in the required thrust increased the lift-to-drag ratio of the counter rotating system in comparison with that of the co-rotating system. Configuration with propellers concentrated at the wing tip increased the lift and drag. However, when the tip propeller was fixed at the wing tip, with the other propellers concentrated in the vicinity of the wing center, the lift increased more, while the drag decreased.
      PubDate: 2022-04-07
       
  • Performance Design of a Turbofan Engine Using Multi-objective Particle
           Swarm Optimization (MOPSO)

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      Abstract: Abstract The performance design of a turbofan engine is carried out to find a set of Pareto optimal solutions satisfying multiple conflicting and/or competing objectives simultaneously within objective constraints by applying multi-objective particle swarm optimization. A gas path analysis is incorporated into the optimization framework to obtain engine performance parameters. The optimization is designed to accomplish two objectives: higher thrust and less fuel consumption. It does so with five design variables and two objective constraints, although the number of simulation parameters is basically unlimited. The present multi-objective particle swarm optimization framework produces well-spread Pareto fronts for the cases with and without constraints. In addition, the parallel coordinates represent the dependency of the design variables on the objectives, which provides insights into the relationship between design variables and engine performance.
      PubDate: 2022-04-07
       
  • Simultaneous Control of Battery Charging and Load-Following for Gasoline
           Electric Power Systems with Output Ratio Control by a Single Parameter

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      Abstract: Abstract Combustion engine-based gasoline electric power system is another solution to extend flight time of the multi-copter drones, which are parallelly connected with batteries. In general, the control unit charges the battery based on the SOC (state of charge) signal from the BMU (battery management unit). If the SOC is less than predefined threshold, the control unit starts battery charging by adjusting the engine power until the battery is charged up to specific SOC (Kim in A study on the preliminary design of series hybrid-electric propulsion system for a fixed wing VTOL unmanned aerial vehicle. Master’s Degree Thesis in Hanyang University, 2016; Zhang and Mi in World Electr Veh J 3:843–848, 2009). This method is well known as Hysteresis or Bang-bang control and is good enough for generic gasoline electric power systems. Since the continuous charge and discharge characteristics of this method, it keeps the battery busy so the lifetime of the battery would be shortened and the system efficiency is affected by the battery charge/discharge efficiency. In this thesis, a control method for simultaneous battery charging and load-following for gasoline electric power systems is presented. This proposed method enables not only the gasoline electric power system to follow the load power in real time but also emulates CC–CV (constant current, constant voltage) battery charging and output ratio control features by only a single user control parameter. Moreover, thanks to the load-following feature, the battery stays in almost idle state (no charge/discharge) in normal operation so it makes the battery’s lifetime longer, and the system efficiency is not affected by charge/discharge efficiency of the battery.
      PubDate: 2022-04-01
       
  • Surrogate Model Considering Trim Condition for Design Optimization of
           High-Aspect-Ratio Flexible Wing

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      Abstract: Abstract An improved, bilevel surrogate model to optimize aerodynamic/nonlinear structural coupled problems, considering trim conditions, is proposed in this paper. The proposed model is applied to a high-aspect-ratio flexible wing. Computational fluid and structural dynamic codes are loosely coupled and interact with the coupling variables of pressure and displacement. Level 1 reduces the coupling variables, using proper orthogonal decomposition, enabling the expansion of any data field as a linear combination of several modes. Level 2 builds the surrogate model, considering proper orthogonal displacement coefficients and the angle of attack as input parameters and the pressure coefficients as output parameters. Unlike the conventional bilevel surrogate model, the improved bilevel surrogate model includes the angle of attack as an input parameter to facilitate the immediate calculation of the trim angle of attack. The wing model of Global Hawk is optimized using the improved bilevel surrogate model, and the conventional bilevel surrogate model was used to compare the results of design optimization under two conditions: including and excluding the trim condition.
      PubDate: 2022-04-01
       
  • Effects of the CG Positions on the Autorotative Flight of Maple Seeds

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      Abstract: Abstract The present study performed 6-degree-of-freedom (6DOF) simulations of the autorotative flight of maple seeds to investigate the interrelation between the motion parameters and the configuration elements, especially the center of gravity (CG). An artificial maple seed of CG point adjustable was designed, and its autorotative flight was simulated by simultaneously solving the flow field around the seed and its 6DOF motion. The spinning rate and the magnitude of the pitch angle (which is always negative) increased as the CG point moves forward toward the leading edge of the seed. It was found that the chordwise position of CG, which determined the value of the moment about the span axis and consequently governed the pitch angle, was very influential to the transient behavior and the converged values of the motion parameter of the autorotative flight of maple seeds. However, the effects of the CG point movement in the spanwise direction were relatively small compared to the CG point movement in the chordwise direction.
      PubDate: 2022-04-01
       
  • Cost Estimation of Earth Observation Satellites Based on Technology-Aware
           Complexity and Cost Adjustment

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      Abstract: Abstract This study proposes a concept of the technology-aware complexity, representing the system performance characteristics considering the technological progress. A new procedure to estimate the Earth-observation satellite development cost using the proposed technology-aware complexity and the cost adjustment has been introduced. The procedure can utilize the satellite database smartly/effectively for an accurate cost estimation—particularly during the early project development phase. A case study on the cost estimation of an existing satellite system demonstrates the proposed procedure’s validity.
      PubDate: 2022-04-01
       
  • Proximal Policy Optimization for Multi-rotor UAV Autonomous Guidance,
           Tracking and Obstacle Avoidance

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      Abstract: Abstract A Markov decision process model with two stages of long-distance autonomous guidance and short-distance autonomous tracking of obstacle avoidance was developed in this study, aiming to address the performance problem of multi-rotor unmanned aerial vehicles (UAV) to ground dynamic target. On this basis, an improved proximal policy optimization (PPO) algorithm is proposed. The proposed algorithm uses long short-term memory (LSTM) network to calculate reward values, update network parameters and perform adaptive optimization iterations through status information, such as the real-time position relationship between the UAV and the target, taking into account the time-sequential data received from the UAV and the environmental context information. Finally, experiment with simulation testing was performed on platform based robot control system species. The results showed that the method proposed in this paper is able to safely and effectively realize autonomous maneuvering during the entire process of the reconnaissance mission. Compared with the traditional PPO algorithm, the introduction of LSTM neural network shortened the model training time, considerably improved the efficiency of tracking and avoiding obstacles, as well as further strengthened the robustness, accuracy, and real-time ability of the algorithm.
      PubDate: 2022-04-01
       
  • Post Flight Analysis Using Numerical Weather Prediction Data, KLAPS

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      Abstract: Abstract Numerical weather prediction data, in this study, were proposed to replace the meteorological measurement data acquired by widely used radiosonde, for the purpose of constructing atmospheric environment model applying to post flight analysis, especially evaluating aerodynamic performance in flight. KLAPS (Korea Local Analysis and Prediction System), the numerical weather model used in this study, is provided by the Korea Meteorological Administration every hour through the Internet and contains the meteorological information for a local region around the Korean peninsula, which is expected to give some advantage in the acquisition of regional and temporal variation of atmosphere state over the radiosonde measurement which has some drawbacks of acquiring data on only one point at one height while drifting via wind and taking some hours to climb up to 30 km high. The accuracy of KLAPS was verified by regenerating vertical distributions of atmospheric properties at the same locations and times as radiosonde measured and comparing them. Post flight analysis was carried out with an atmosphere environment model based on KLAPS and proved that the numerical weather model can provide an accurate atmospheric environment model enough to substitute the radiosonde measurement data.
      PubDate: 2022-03-15
       
  • Circumnavigation of Multiple Drones Under Intermittent Observation: An
           Integration of Guidance, Control, and Estimation

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      Abstract: Abstract This paper discusses the circumnavigation of multiple drones around a moving target in an urban area and proposes an integrated solution accounting for estimation, guidance and control. For performing this circumnavigation task, three objectives must be achieved at a steady state: (1) The target and the drones must be on the same plane; (2) The drones must rotate around the target while maintaining a constant distance to the target; and (3) Each drone must be able to avoid collisions with the other drones. To achieve these three objectives, a vector-field-based guidance law can be designed to generate the velocity command which is then integrated to be the position command for each drone. However, in the course of implementing this guidance law, the target’s position and velocity information is continuously required, which is unlikely to be the case in an urban environment. To address this issue, a probability function modeling the intermittent or discontinuous observation can be added to the typical Kalman filter, so that the target position is continuously estimated. In addition, when there is a bias in the observation of drone, the bias has to be eliminated by adding a consensus logic (information exchange between neighboring drones) to the correction step of the Kalman filter, resulting in so-called Kalman Consensus Filter (KCF). However, KCF only guarantees the asymptotic convergence to an estimate of the target state which adversely affects the control performance, and so a novel consensus logic, so-called Kalman Finite-time Consensus Filter (KFCF), is proposed for the finite-time convergence and the control performance improvement. The guidance law combined with the estimation scheme (KFCF) is then tracked by each drone being equipped with the Integral Sliding Mode Control (I-SMC) law yielding the finite-time convergence to a prescribed sliding surface in the presence of bounded disturbances. Integrated numerical simulations show the merit of the proposed method.
      PubDate: 2022-03-09
       
  • Control-Oriented Modeling of a Three-Dimensional Hypersonic Vehicle with
           Rigid/Flexible Coupling

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      Abstract: Abstract Modeling for a hypersonic vehicle is a great challenging task due to its tightly integrated airframe/propulsion system and flexible structure. A three-dimensional, six-degree-of-freedom, physics-based hypersonic vehicle model is being established that can capture the real physical characteristics for control studies. Flexible effects, aerodynamic loads and viscous effects are calculated using or combining variation method, shock/expansion theory and Eckert’s reference temperature method. Based on curve fit approximation of the forces and moments of the vehicle, a control-oriented six-degree-of-freedom model is then developed. The simulations illustrate that the surrogate model contain aerodynamic/structure/propulsion interactions of the vehicle, and can support designing of the model-based control.
      PubDate: 2022-02-07
      DOI: 10.1007/s42405-022-00443-w
       
 
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