The current research aims to design a novel concept for an efficient wing buoyancy assisted aircraft (EWBA) by investigating the optimum aerodynamic efficiency of next-generation aircraft features; ...this EWBA is entirely different from a current traditional airship and aircraft. In the relevant literature, very little attention has been paid to optimising the design features by computational design point methods case of an airship. The 3D model of 6:1 prolate spheroid, tail hull, straight wing hull, and efficient wing buoyant airship (EWBA) was designed in Solidworks after several iterations. Then, the pressure- base ANSYS Fluent (Ansys 16.1) solver was successfully employed for investigating the aerodynamic performance of efficient wing buoyant airship (EWBA), planner wing, and tail hull airship and compared its aerodynamic parameters; namely the lift coefficient, drag coefficient, and lift to drag ratio by using the Reynolds-averaged Navier-Stokes (RANS) governing equation (k-ε) and the RSM model.
Optimal tracking control for underactuated airship Atyya, Mohamed; ElBayoumi, Gamal M.; Lotfy, Mohamed
Journal of engineering and applied science (Online),
12/2024, Volume:
71, Issue:
1
Journal Article
Peer reviewed
Open access
A non-linear mathematical model of underactuated airship is derived in this paper based on Euler-Newton approach. The model is linearized with small disturbance theory, producing a linear time ...varying (LTV) model. The LTV model is verified by comparing its output response with the result of the nonlinear model for a given input signal. The verified LTV model is used in designing the LQT controller. The controller is designed to minimize the error between the output and required states response with acceptable control signals using a weighted cost function. Two LQT controllers are presented in this work based on two different costates transformations used in solving the differential Riccati equation (DRE). The first proposed assumption of costates transformation has a good tracking performance, but it is sensitive to the change of trajectory profile, whereas the second one overcomes this problem due to considering the trajectory dynamics. Therefore, the first assumption is performed across the whole trajectory tracking except for parts of trajectory profile changes where the second assumption is applied. The hybrid LQT controller is used and tested on circular, helical, and bowed trajectories. The simulation assured that the introduced hybrid controller results in improving airship performance.
Abstract
We consider the construction of the mathematical model of motion in the vertical plane of an airship of the classical scheme and algorithms for calculating the parameters of its steady-state ...motion in various cases. The motion of an airship of rather small volume, for example, a remotely piloted airship, is investigated. Some types of possible motions in the vertical plane satisfying the proposed system of equations of steady-state motions are described. Such motions include horizontal flight with constant velocity, rectilinear flight in climbing mode, and descent at a constant trajectory slope angle. The cases of rectilinear flight of an airship along inclined trajectories, the inclination angle of which is not small, taking into account the nonlinear components of the aerodynamic characteristics, are also considered. We have developed algorithms for calculating the steady-state motions of an airship for various cases of flight along inclined trajectories corresponding to various methods of takeoff and landing of an airship without a special cable landing system. This allows us to construct trajectories that provide short takeoff distances and low landing speeds of the airship, which corresponds to the solution of the problem of safe operation of the airship as a technical system. The results of numerical calculations of steady-state motion parameters obtained in accordance with the constructed algorithms are presented. The calculation results are presented graphically.
Abstract
For solving added mass of stratospheric airship, take the method of planar motion mechanism numerical simulation, calculate main diagonal added mass of standard ellipsoid model, and then ...calculate main diagonal added mass and other coupling added mass of stratospheric airship with X-shaped tail. Error between calculated value and theoretical value is 2.94%~4.29%, that validates the method is feasible and effective; stratospheric airship added mass is expressed by matrix. Comparison with wind tunnel test, the calculation error of stratospheric airship with X-shaped tail added mass λ55 and λ66 are -25.8% and -19.7%. The result shows that the method of planar motion mechanism numerical simulation can solve added mass matrix of arbitrary shape stratospheric airship, not just main diagonal added mass; Compared with the added mass on the main diagonal, the coupling added mass at other positions is small.
Flying base stations (FlyBSs) can serve space-time varying heterogeneous traffic in the areas, where a deployment of conventional static base stations is uneconomical or unfeasible. We focus on ...energy consumption of the FlyBSs serving moving users. For such scenario, rotary-wing FlyBSs are not efficient due to a high energy consumption while hovering at a fixed location. Hence, we consider airship-based FlyBSs. For these, we derive an analytical relation between the sum capacity of the users and the energy spent for flying. We show theoretical bounds of potential energy saving with respect to a relative sum capacity guarantee to the users for single FlyBS. Then, we generalize the problem towards multiple FlyBSs and we propose an algorithm minimizing the energy consumption of the FlyBSs serving moving users under a constraint on the minimum relative sum capacity guarantee. The proposed algorithm reduces the energy consumed by the airship-based FlyBSs for flying by dozens of percent at a cost of only a marginal and controlled degradation in the sum capacity. For example, if the degradation in the sum capacity up to 1% is allowed, 55.4%, 67.5%, and 90.7% of the energy is saved if five, three, and one FlyBSs are deployed, respectively.
This paper proposes an adaptive horizontal trajectory control method for stratospheric airships in uncertain wind field using Q-learning algorithm. Firstly, horizontal trajectory control of the ...airships is decomposed into the target tracking, and the observation model of airships is constructed. Then, the Markov decision process (MDP) model of airships is established, in which the action strategy is determined by the wind direction, and a cerebellar model articulation controller (CMAC) neural network is designed to optimize the action strategy for each state. Finally, numerical simulations demonstrate that the proposed control method performs well stability and intelligent decision-making ability in the process of horizontal trajectory control for stratospheric airships.
•Thermal and output power models of solar powered airship are developed.•Effects of PV array on thermal behaviors of a stratospheric airship are discussed.•Thermal effect on output power of solar ...cells is unneglectable.•Solar absorptivity and IR emissivity are vital factors affecting the output power.
Thermal characteristics and output power performances are important factors to be considered in the design and operation of long endurance stratospheric airships. The thermal and output power models of stratospheric airships with solar array are established in this paper. Based on the models, a numerical simulation program is developed. The thermal and output power performances of a solar powered airship are simulated. The effects of solar array on the thermal performances of a stratospheric airship are discussed. The factors affecting the output power of solar cells are studied in detail. The results are conducive to understanding the thermal and output power behaviors of solar powered stratospheric airships.
The resurgence of airships has created a need for dynamics models and simulation capabilities adapted to these lighter-than-air vehicles. However, the modeling techniques for airship dynamics have ...lagged behind and are less systematic than those for fixed-wing aircraft. A state-of-the-art literature review is presented on airship dynamics modeling, aiming to provide a comprehensive description of the main problems in this area and a useful source of references for researchers and engineers interested in modern airship applications. The references are categorized according to the major topics in this area: aerodynamics, flight dynamics, incorporation of structural flexibility, incorporation of atmospheric turbulence, and effects of ballonets. Relevant analytical, numerical, and semi-empirical techniques are discussed, with a particular focus on how the main differences between lighter-than-air and heavier-than-air aircraft have been addressed in the modeling. Directions are suggested for future research on each of these topics.
Based on commercial passenger-carrying airships like LZ129 or R100, a hypothetical electric rigid framed airship including a solar cell covered surface and a lithium-ion battery is designed. The size ...of the battery and the coverage with solar cells are selected such that long-haul flights are possible. To simulate flight times, weather data from 2019 and time-dependent solar irradiation are used. Travel route and battery use are optimised in order to reduce flight times. For a mid-range and long-haul use case for passenger or freight transport, travel times have been calculated. Building on these results, analysis of CO
2
emissions, land-use, and operating costs are carried out to reveal that depending on the use case, CO
2
emissions of solar-powered airships could be as low as 1% to 5% of the emissions of a conventional aircraft at an estimated energy consumption in USD per km of 0.5% to 2.5%.
This study presents a comprehensive analysis of the design considerations and trade-offs involved in developing a stratospheric airship with in-flight gas replenishment based on regenerative fuel ...cells (RFC). To address the challenge of lift gas leakage and enhance flight endurance, the primary aim is to optimize energy acquisition, storage, and buoyancy maintenance. A solution utilizing RFCs to supply lift gas has been proposed, leveraging the combined utilization of hydrogen for energy and buoyancy maintenance. The flight endurance model considering thermal effects, energy system and gas leakage is established to provide insights into its potential for extending the flight endurance of stratospheric airships by 25.5 % based on the design of Stratobus. Scaling up the energy system provides surplus energy for hydrogen production; however, it may impact gas-tightness due to increased weight allocation. Various weight configurations were evaluated, demonstrating the significant impact of weight distribution on endurance. Without gas replenishment, the longest endurance was 60.4 days. With increased energy storage distribution and gas replenishment consideration, endurance improved to 87.2 days. Furthermore, a longer flight endurance extension to 118.2 days can be reached by applying a gasbag storage system. This underscores the importance of exploring innovative storage solutions to achieve longer endurance.
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