Subjects -> ENGINEERING (Total: 2844 journals)     - CHEMICAL ENGINEERING (259 journals)    - CIVIL ENGINEERING (255 journals)    - ELECTRICAL ENGINEERING (182 journals)    - ENGINEERING (1420 journals)    - ENGINEERING MECHANICS AND MATERIALS (454 journals)    - HYDRAULIC ENGINEERING (60 journals)    - INDUSTRIAL ENGINEERING (101 journals)    - MECHANICAL ENGINEERING (113 journals) ENGINEERING (1420 journals)                  1 2 3 4 5 6 7 8 | Last
Similar Journals
 Aerospace SystemsNumber of Followers: 10      Hybrid journal (It can contain Open Access articles) ISSN (Print) 2523-3947 - ISSN (Online) 2523-3955 Published by Springer-Verlag  [2658 journals]
• Concept of application of water electrolysis propulsion system as a
component of a universal space platform for asteroid exploration mission

Abstract: The article presents the concept of a universal space platform with a propulsion system based on water electrolysis. The spacecraft based on the platform is used for an asteroid research mission. The mission task is to extract water from the target asteroid and refuel the spacecraft. The requirements for such a performance of a universal space platform are proposed. The advantages and disadvantages of using such propulsion systems in small spacecraft are highlighted.
PubDate: 2021-10-13

• Correction to: Spatio-temporal graph convolutional neural network for
remaining useful life estimation of aircraft engines

PubDate: 2021-10-05

• The research on intelligent cooperative combat of UAV cluster with
multi-agent reinforcement learning

Abstract: With the rapid development of computer hardware and intelligent technology, the intelligent combat of unmanned aerial vehicle (UAV) cluster will become the main battle mode in the future battlefield. The UAV cluster as a multi-agent system (MAS), the traditional single-agent reinforcement learning (SARL) algorithm is no longer applicable. To truly achieve autonomous and cooperative combat of the UAV cluster, the multi-agent reinforcement learning (MARL) algorithm has become a research hotspot. Considering that the current UAV cluster combat is still in the program control stage, the fully autonomous and intelligent cooperative combat has not been realized. To realize the autonomous planning of the UAV cluster according to the changing environment and cooperate with each other to complete the combat goal, we propose a new MARL framework which adopts the policy of centralized training with decentralized execution, and uses actor-critic network to select the execution action and make the corresponding evaluation. By improving the structure of the learning network and refining the reward mechanism, the new algorithm can further optimize the training results and greatly improve the operation security. Compared with the original multi-agent deep deterministic policy gradient (MADDPG) algorithm, the ability of cluster cooperative operation gets effectively enhanced.
PubDate: 2021-09-30

• Nonlinear dynamic modeling of spacecraft relative motion in elliptical
orbit via power series approach for rendezvous and proximity operations

Abstract: As interest in the use and launching of spacecraft for communications, earth observation, scientific experiment and navigation purposes increases and manned missions to the Moon and Mars intensify, there is need for the design of efficient and high-fidelity relative motion dynamics to reduce spacecraft collisions and increase return on investment. The main aim of this work is to develop new approximate solution of spacecraft relative motion in elliptical orbit via power series method. Advantage of this method is that it does not involve evaluating complex integral I as employed for developing approximate solutions of linearized Tschauner–Hempel equations. Cauchy product, used for the discrete convolution of power series, is employed for the development of power series solutions of the approximated nonlinear spacecraft relative motion. Application of Cauchy criterion shows that the new solutions are convergent making them useful for spacecraft formation flying, proximity and rendezvous mission analysis.
PubDate: 2021-09-30

• LMI-based linear parameter varying PID control design and its application
to an aircraft control system

Abstract: To bridge the gap between real-world applications and theoretical achievements, this paper proposes a new synthesis approach of gain-scheduled proportional–integral–derivative (PID) control for linear parameter-varying (LPV) systems. It is recognized that the synthesis problem of PID controllers for LPV systems should be formulated as nonconvex optimization problems. To avoid this situation, using a special matrix transformation, novel synthesis conditions with linear matrix inequality constraints are provided in this paper. The stability of the resulting closed-loop system is guaranteed theoretically based on a parameter-dependent Lyapunov function, and two types of robust performance (bounded $$L_2$$ norm and induced $$L_2$$ norm) are also achieved in the corresponding synthesis conditions. Then, the control system of aircraft is designed based on the proposed method, and the system responses are compared with the traditional LPV-PID control and the LPV dynamic output feedback control.
PubDate: 2021-09-21

• Multiband image fusion using total generalized variation regularization

Abstract: Multiband image fusion has become a thriving area of research in a number of different fields, such as space robotics, and remote sensing, etc. Many multiband image fusion methods have been proposed for hyperspectral sharpening with panchromatic images, hyperspectral sharpening with multispectral images and panchromatic images, etc. Despite the different motivations, we observe that many existing methods possibly lead to over-smooth regions. In this work, we consider a new problem formulation of two image fusion problems. A novel fusion model with total generalized variation regularization term is proposed, where the fusion process is performed on hybrid gradient domains. The optimization framework of alternating direction multiplier of method is used to solve the resulting problem. In an extensive evaluation, our method outperforms some state-of-the-art methods.
PubDate: 2021-09-01
DOI: 10.1007/s42401-020-00075-6

• Design and computational fluid dynamics analysis of bio-inspired non
slender cropped delta wingsuit

Abstract: This study examines the effect of bio-inspired serrations on aerodynamic performance of a Non Slender cropped delta wingsuit model. In this study, Gottingen 228 aerofoil is used for designing the wingsuit model having AR of 1.00 using CAD software Solidworks. Ansys Fluent solver has been utilised to solve the Reynolds Averaged Navier–Stokes (RANS) equations with a k− $$\omega$$ turbulence model. The flow velocity was kept at 45 m/s with Re ~ 2.6 × 106 and angle of attack was varied from 0° to 45°. Computations revealed that the wingsuit with serrations in comparison with clean basemodel had a notable increase in maximum lift coefficient. The results were compared with the experimental and CFD results of existing literature in the open domain. The serrated non slender delta wingsuit performs extremely well giving a lift coefficient of 2.74 and $$C_{{\text{L}}}$$ / $$C_{{\text{D}}}$$ of 9.72. The results were validated by comparing them with flat plate and non slender cropped delta wing results available in the existing literature. A good agreement in terms of trends was obtained for $$C_{{\text{L}}}$$ and $$C_{{\text{D}}}$$ which indicates that proposed wingsuit should perform well aerodynamically under typical wingsuit flying conditions.
PubDate: 2021-09-01
DOI: 10.1007/s42401-021-00088-9

• Future communication satellites: low cost reduction of technology
obsolescence

Abstract: Rapid technological advances cause the obsolescence of communication satellite payload at the launch epoch. The software defined radio (SDR) is reconfigurable and is suitable to address technological obsolescence in satellites. However, SDRs have a finite flexibility and reconfigurability. This paper proposes the use of high-altitude platforms (HAPs) with low launch costs to reduce technology obsolescence in satellites. The SDR on the HAP can be easily upgraded and does not need radiation hardening to survive in space. The HAP is a virtual extension of an in-orbit satellite and they are jointly referred to as cloud aided satellite (CAS). This paper proposes the use of open source hardware for the CAS to lower the payload acquisition costs and the use of neuromorphic hardware instead of Von Neumann hardware in satellite communications. Results show that the incorporation of CAS and neuromorphic hardware enhances system performance, where the data transmit power, downlink channel capacity are improved by an average of up to 45.7% and 34.2%, respectively. Lastly, the use of the HAPs in the proposed CAS also reduces the forwarding latency by 14.4% on average.
PubDate: 2021-08-25
DOI: 10.1007/s42401-021-00102-0

• Correction to: Analysis of BDS GEO satellite multipath effect for GNSS
integrity monitoring in civil aviation

PubDate: 2021-08-17
DOI: 10.1007/s42401-021-00100-2

• GNSS vulnerability reliable assessment and its substitution with

Abstract: Global Navigation Satellite System (GNSS) vulnerability researches aim to improve GNSS application reliability, and is of great significance to the continuity of positioning, navigation, and timing services. The research on GNSS vulnerability can be roughly divided into three parts: vulnerability assessment, traceability and substitution. This paper surveys state-of-the-art GNSS vulnerability research and supplements the vulnerability research system. Under the premise that GNSS is highly vulnerable, a real-time positioning system is designed in which visual fiducial markers is used to assist visual–inertial odometry. The experiment using simulation data as observation data proves that the method proposed in this paper can effectively reduce the positioning error in visual–inertial odometry.
PubDate: 2021-08-09
DOI: 10.1007/s42401-021-00099-6

• Decentralized project management concept for schedule-critical space
projects

Abstract: The Apollo moon missions of the 1960s pioneered the classic phased approach to space mission management. While successful at the time, this rigid and inflexible management philosophy has become synonymous with cost and schedule overruns of most high-profile space missions. The software industry has recently adopted modern, more flexible project management techniques based on “lean-agile” methods that enable team collaboration and communication through distributed task and schedule management, online document sharing and rolling-wave planning. However, due to the inherent schedule complexities of hardware development and the firm constraints of design review and launch timelines, flexible project management frameworks have not been widely adopted for space mission management. This paper presents a modified version of the traditional agile management philosophy, adapted to the unique needs of the space industry. A recent satellite development project was managed using the new modified-agile approach, while collecting project hours and task durations. Comparisons were made between this new style of space project management and a recently completed satellite development project using traditional space project management techniques. Results show that the new management approach reduced strain on the project team, improved overall productivity, and maintained a more level task loading when compared to the traditional management approach. This paper also illustrates how the new management approach can enable project resilience to change by analyzing its response to the labor disruptions caused by the COVID-19 pandemic.
PubDate: 2021-07-20
DOI: 10.1007/s42401-021-00098-7

• Mechanical responses of folded structures from the generalized Resch
patterns

Abstract: Foldcores are considered as a kind of lightweight sandwich structures that have the potential to replace honeycomb core materials, especially in the field of aerospace manufacturing. Although foldcores based on Miura-ori and its derivative configurations have been extensively studied, such foldcores are relatively weak at the junction between the core material and the skin. The generalized Resch-based foldcores that can solve this defect are researched in this paper. We first compared the static mechanical properties of the triangular, quadrilateral, and hexagonal generalized Resch patterns during compression. The mechanical properties were analyzed using a fast tool called MERLIN and compared with the finite element method's results. The results show that among the three types of configurations with the same height, the triangular generalized Resch element has greater stiffness and energy barrier to transform. As the number of sides of the basic polygon increases, the stiffness and energy barrier become smaller.
PubDate: 2021-07-06
DOI: 10.1007/s42401-021-00096-9

• Correction to: End-of-life geostationary satellite removal using realistic
flat solar sails

Abstract: A correction to this paper has been published: https://doi.org/10.1007/s42401-021-00089-8.
PubDate: 2021-06-14
DOI: 10.1007/s42401-021-00094-x

• Flight management system for hydrogen-powered aircraft in cruise

Abstract: The minimization of the direct operating cost for hydrogen-powered aircraft is formulated in this paper as an optimal control problem and is solved based on Pontryagin’s minimum principle. As a consequence, the optimum cruise flight speed is determined assuming cruising at a constant altitude. The optimization criterion corresponds to the minimization of a functional representing the trade-off between the cost of hydrogen fuel and time-dependent costs, which are related by a parameter denoted by cost index. The value of this parameter is introduced by a pilot into the flight management system of the aircraft. The HY4 aircraft model is used to obtain numerical results for the proposed methodology.
PubDate: 2021-06-14
DOI: 10.1007/s42401-021-00097-8

• Analysis of BDS GEO satellite multipath effect for GNSS integrity
monitoring in civil aviation

Abstract: With the great development of Global Navigation Satellite System (GNSS), multi-GNSS constellations (GPS, BDS, GLONASS, and Galileo) are able to provide users with more accurate positioning result. For civil aviation, to guarantee user’s safety, multi-constellation GNSS needs to meet the integrity requirement. Using conservative error models, Multiple Hypothesis Solution Separation (MHSS) Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is proposed to evaluate GNSS integrity. Current multipath error model in ARAIM algorithm is based on data of GPS Medium Earth Orbit (MEO) satellites. But BDS is a hybrid constellation. For BDS II, there has 5 Geosynchronous Earth Orbit (GEO) satellites. Previous studies have shown that the multipath effect of GEO satellites has statistical characteristics different from MEO satellites. Meanwhile, the multipath magnitude of GEO satellites is larger than that of MEO satellites. This paper mainly focuses on validating whether the multipath error model in ARAIM algorithm is conservative enough for GEO satellites. In this paper, Code Minus Carrier (CMC) residuals are calculated for BDS GEO dual-frequency signals. Then the Standard Deviation (STD) of CMC residuals can be conservatively estimated by bounded Cumulative Distribution Function (CDF). After eliminating interference from receiver noise, STD of GEO multipath can be obtained. Comparing the STD of GEO multipath effect with ARAIM multipath error model, a conclusion could be drawn that current multipath error model in ARAIM algorithm is no longer able to conservatively estimate the statistical characteristics of GEO satellites.
PubDate: 2021-06-01
DOI: 10.1007/s42401-020-00074-7

• An enhanced situational awareness design for airborne surveillance based

Abstract: With the fast growth of general aviation, Automatic Dependent Surveillance–Broadcast (ADS-B) becomes the direction of airspace surveillance development. The previous researches in surveillance field have managed to use ADS-B data to improve the performance of the integrated surveillance system, yet they have failed to consider ADS-B as a major source of data and will not be applicable when the general aviation is growing fast. The research of this paper proposes an enhanced situational awareness design based on ADS-B. With elective fusion based on surveillance quality, it helps to improve the performance when ADS-B data are taken as a major source of surveillance data. Several simulation scenarios with different surveillance quality are tested. The results show that the error is reduced and the overall surveillance performance is improved when surveillance quality is low. An integrated display is built for enhanced situational awareness display afterwards. With this enhanced situational awareness design, the pilots can be provided with a more comprehensive awareness of the airspace including general aviation aircrafts.
PubDate: 2021-06-01
DOI: 10.1007/s42401-020-00081-8

• A trade-off methodology for micro-launchers

Abstract: The trend of cost-effective access to space and satellite technologies’ evolution is increasing the small satellite market. However, small payloads usually ride as piggyback, being a secondary passenger of a space vector, with very low flexibility in target orbit and launch schedule. The micro-launchers are designed to answer the needs of the small satellite missions, with a payload capacity up to 350 kg to Low Earth Orbit, aiming to low turn-over time and competitive prices. This paper explains the work performed by Politecnico di Torino in support of the ESA–ESTEC activities on micro-launchers. The aim is to provide preliminary guidelines for choosing and evaluating new innovative micro-launcher flight vehicle engineering processes. A trade-off methodology is proposed and defined based on the Analytically Hierarchical Process (AHP). This methodology considers, among other features, the flight profile, maximum payload, and physical characteristics. To support the trade-off analysis, a software tool is built for the automatic generation of the aerodynamics and propulsion parameters needed for the completion of the preliminary designs, enabling the performance estimation. The launcher’s performance models, with an analysis of the take-off sites and target orbits, are also produced. This allows the definition of performance maps where the maximum payload is graphed as a function of the orbit altitude and inclination. A set of innovative micro-launchers exploiting different technologies is also assessed as a case study.
PubDate: 2021-05-27
DOI: 10.1007/s42401-021-00095-w

• End-of-life geostationary satellite removal using realistic flat solar
sails

Abstract: This paper proposes an analytical solution of removing end-of-life GEO satellites to the GEO graveyard region using realistic flat solar sails. Different from the ideal solar sail model, the proposed realistic flat solar sail model applies the realistic solar sail thrust model, and the sail cone angle is constrained within $$[0^{\circ },85^{\circ }]$$ . The dynamic system of a GEO satellite equipped with a realistic flat solar sail is constructed based on the Gauss’s variation of parameter (VOP) equations, and linearized along a nominal trajectory. Control angles of the sail are generated using the linear optimal tracking controller. Iterations of linearization are applied to gradually reduce the inaccuracy of the linearized systems, thus reducing the terminal state error. Simulations indicate that, end-of-life GEO satellites are successfully removed to the GEO graveyard region in 350 days using the proposed control approach. The negative impact of using realistic flat solar sails in the end-of-life GEO satellite removal mission is evident but not significant. Compared to using ideal solar sails, a small increase in the A/m of spacecraft from 0.14 to $$0.16\ \mathrm{kg}/\mathrm{m}^2$$ is required.
PubDate: 2021-04-19
DOI: 10.1007/s42401-021-00089-8

• Development turbine air-cooling system of GTE to increase its operating
parameters

Abstract: The results researching of structural schemes cooling for turbines of aircraft bypass gas turbine engines are presented. A new scheme of supplying cooling air to the high-pressure turbine working blades is proposed. The front cavity of the nozzle and rotor blades is cooled continuously, regardless of the engine’s operating mode. The air for cooling the working blade of the high-pressure turbine is supplied by the transit tube through the vane from the cavity, which is located in front of the place where is supply locking, which ensures constant boost of the blade front cavity. To eliminate the heating from the turbine disk and centrifugal pumping, the swirling device is installed directly under the blade lock, where the supply of cooling air to the cavity is organized. The turbine disk is cooled by the second row of swirling device with air taken from the secondary zone of the combustion chamber. The swirling devices rows are separated by brush seal and labyrinth. The higher efficiency of the brushes, the location of the swirling device cooling the disk under the labyrinth in the upper part of the disk, the decrease in the number of labyrinth teeth and, as a result, the pressure drop across the labyrinth between the disk cooling cavity and the dummy cavity eliminates heating air cooling blade because the main part of the hotter air is to be directed down the disk and, further, along the shaft of the high-pressure rotor into the dummy cavity.
PubDate: 2021-04-16
DOI: 10.1007/s42401-021-00086-x

• Substantiation of choosing rational appearance of nose of aircraft with
the use of mathematical modeling

Abstract: As part of this work, a comprehensive analysis of the question of ensuring the specified aerodynamic performance of the aircraft required to implement a cruising supersonic flight at M ~ 1.5. B Analysis of possible methods of aerodynamic performance evaluation (AP) of aircraft components in the course of optimization of their geometrical parameters to achieve a minimum contribution to the AP. The paper presents an algorithm for the formation of the nose part of the aircraft of minimal aerodynamic resistance, and also selects criteria for evaluation of the nose part of the aircraft as an element of the glider, which has a significant contribution to the overall aircraft AP at a flight speed of $$M>1$$ . The results of this work can be used at the early stages of aircraft tying up to reduce the time required for the formation of a mathematical model of the surface of a prospective aircraft.
PubDate: 2021-02-22
DOI: 10.1007/s42401-020-00079-2

JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762

Home (Search)
API
News (blog, publications)