Unlimited Endurance Performance of Solar UAVs with Minimal or Zero Electrical Energy Storage

Sachs, Gottfried; Lenz, Jakob; Holzapfel, Florian

doi:10.2514/6.2009-6013

Cited by 32 publications

(28 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, how many rechargeable batteries should be taken for longendurance purpose is a crucial problem needed to be solved for the designers of solar-powered aircraft. Prof. Sachs G. formulates the trajectory planning problem of solar-powered aircraft from a new viewpoint: The surplus energy of solar powered during day can be stored by gravitational potential [65]. He has demonstrated in the paper that with an appropriate trajectory control, it is possible for the solar-powered aircraft to stay aloft during night with minimum or even no solar energy to be stored in rechargeable battery.…”

Section: Energy Storage By Gravitational Potentialmentioning

confidence: 98%

“…Besides, there are also several other methods in consideration, such as to extract energy from wind shear [59][60][61][62][63] and store energy by gravitational potential [64][65][66][67] for solar-powered aircrafts. Although lots of works have been done, it is still not a simple task for the designers of solarpowered aircraft to select a particular technique from a number of existing techniques, since each technique has certain advantages and disadvantages with respect to different performance indices to fulfill the special requirements.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reviews of methods to extract and store energy for solar-powered aircraft

Gao

Hou

Guo

et al. 2015

Renewable and Sustainable Energy Reviews

View full text Add to dashboard Cite

Section: Energy Storage By Gravitational Potentialmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Reviews of methods to extract and store energy for solar-powered aircraft

Gao

Hou

Guo

et al. 2015

Renewable and Sustainable Energy Reviews

View full text Add to dashboard Cite

“…Here, both lateral coordinates are substituted to the distance d. Furthermore, Equations (4)-(7) include altitude h, flight path angle γ, weight m and gravitational constant g (see also [16,17]). Thrust T provided by the propeller and drag D are assumed to be co-linear with V. Wind is not considered and only straight ahead flight, without turns, is regarded as in [14].…”

Section: Modelling Aspectsmentioning

confidence: 99%

The Impact of Peukert-Effect on Optimal Control of a Battery-Electrically Driven Airplane

2020

Self Cite

View full text Add to dashboard Cite

Further investigation on the impact of the so called Peukert effect on optimal control of a battery-electrically driven airplane is presented. To analyse the impact of the Peukert effect, an ideal model without this battery concerning effect and a realistic model containing different Peukert exponents are built up. For the different models, optimal trajectories are generated and altitude dependency of a maximum range horizontal flight criterion is investigated. On the one hand, it can be shown that the Peukert effect causes a special form of optimal trajectories. On the other hand, it turns out that range optimal horizontal flight is more efficient in lower altitudes, if the Peukert effect is taken into account. The particular efficiency properties of battery electrical propulsion can be explained with its consumption characteristic, which appear in form of a power function with real exponent.

show abstract

“…10 As shown in Figure 1, UAV is assumed to fly in still air and the velocity axes are used for the aircraft; thus, the assumption of vertical plane flight induces an assumption of zero yaw angle.…”

Section: Problem Formulation Aircraft Dynamic Modelmentioning

confidence: 99%

“…In order to achieve the goal of attaining a night flight capability requiring as little Sion Power batteries as possible, an appropriate trajectory control during gravitational gliding in night is considered as an efficient method. 10 As a well-known fact, gravitational gliding is the solo mode for solar-powered UVAs in night without electric energy storage batteries. In this mode, UAVs cover the aerodynamic cost by losing potential gravitational energy; thus, it needs a minus path pitch angle to maintain that the projection of gravity on the velocity can counteract the force generated by the airflow on the wings.…”

Section: Introductionmentioning

confidence: 99%

Research on characteristics of gravitational gliding for high-altitude solar-powered unmanned aerial vehicles

Gao

Hou

Guo

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

Gravitational gliding during night without electric power is an efficient method to enhance the endurance of high-altitude solar-powered unmanned aerial vehicles. The properties of the maximum endurance path of gravitational gliding are studied in this article. The maximum endurance path problem is formulated as the problem of the maximum endurance can be sustained by unit altitude difference with the constraints of dynamic equations and aerodynamic parameters. The maximum endurance path is generated by Gauss pseudo-spectral method, and a new way to estimate co-state variables in Hamiltonian is proposed. In order to analyze the sensitivity of initial altitude and velocity of solar unmanned aerial vehicles with its endurance performance, the lift coefficient in the interval [0.4, 1.2] and flight envelopes between 0 and 30 km are investigated. The results are as follows: first, the broad range of lift coefficients can improve solar aircrafts' long-endurance performance; second, the lower the initial altitude, the longer the gliding endurance can be sustained by unit altitude difference; third, it is possible for a solar-powered unmanned aerial vehicle to keep aloft during the whole night just by gravitational potential energy storage, but the issues with turbulence and wind would render this mode of unlimited endurance unfeasible. Thus, gravitational gliding by potential energy storage can only be partly used instead of electric energy storage in application now.

show abstract

Unlimited Endurance Performance of Solar UAVs with Minimal or Zero Electrical Energy Storage

Cited by 32 publications

References 4 publications

Reviews of methods to extract and store energy for solar-powered aircraft

Reviews of methods to extract and store energy for solar-powered aircraft

The Impact of Peukert-Effect on Optimal Control of a Battery-Electrically Driven Airplane

Research on characteristics of gravitational gliding for high-altitude solar-powered unmanned aerial vehicles

Contact Info

Product

Resources

About