Modeling and control design for a prototype lighter-than-air wind energy system

Vermillion, Chris; Grunnagle, Trey; Kolmanovsky, Ilya

doi:10.1109/acc.2012.6315434

Cited by 32 publications

(19 citation statements)

References 9 publications

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“…Because the wind speed can change unpredictably from very low to very high in a short time, it is essential that the shell not only maintain acceptable values of θ under high wind speeds but also under low wind speeds. Depending on the tether attachment points, excess buoyancy, and the relationship between the centers of mass and buoyancy, however, the range of pitch angles that can be attained under low wind speeds can be quite restrictive (see [8] for a detailed analysis of this). Fig.…”

Section: Low-wind To High-wind Flight Transitionmentioning

confidence: 99%

“…30.7, it is impossible for the tethers to impart a force along x t and y t , and it is impossible to directly impart a reaction or control moment about z t . This has significant implications on passive design requirements and controllability, which are described in detail in [8] but summarized here. Ultimately, it is a requirement for passive high-altitude flight and for stabilizability that the shell exhibit a stable weathervane moment about z t , which allows the BAT to passively align with the wind.…”

Section: Passive Alignment With Windmentioning

confidence: 99%

“…Each tether can be modeled as a nonlinear spring-damper that can only assume non-negative tension. This model is straightforward and is detailed in [8]. F t is immediately calculated using this model.…”

Section: Six Degree-of-freedom Model For Shell Dynamicsmentioning

confidence: 99%

“…External forces and moments on the aerostat arise from aerodynamics (F aero ), tether tensions (F t ), and buoyant forces (F b ). Ground-frame positions (x g , y g , and z g ) and attitude (φ , θ , and ψ) are found through appropriate integration of velocity variables (note that this is not simply a direct integration of velocities, see [8] Fig. 30.7 Axis systems for the 6 degree-of-freedom BAT model.…”

Section: Six Degree-of-freedom Model For Shell Dynamicsmentioning

confidence: 99%

“…30.7, including a ground-fixed axis system centered on the base station, a body-fixed system centered at the airborne shell's center of mass, and a tether axis system also centered at the shell's center of mass, with the z t axis aligned with the mean tether direction and the x t and y t axes perpendicular to z t and to each other. The complete model is detailed in [8] and is divided between 4 components, namely the shell, tethers, base station, and winches. The model makes extensive use of previous aerostat dynamic modeling works such as [7]- [5], which provide insight into effective means for modeling key features such as tether dynamics and added mass, which are not present in most standard aircraft models.…”

Section: Six Degree-of-freedom Model For Shell Dynamicsmentioning

confidence: 99%

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Lighter-Than-Air Wind Energy Systems

Vermillion

Glass

Rein

2013

Airborne Wind Energy

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Several wind energy concepts utiliz e airborne systems that contain lighterthan-air gas, which supplements aerodynamic lift and expands these systems' available operating regimes. While lighter-than-air systems can incorporate the traction and crosswind fl ight motions of their heavier-than-air counterparts, several lighterthan-air concepts have also been designed to deliver large amounts of power under completely stationary operation and remain aloft during periods of intermittent wind. This chapter provides an overview of the history of LTA airborne wind energy concepts, including the design drivers and principal design constraints. The focus then turns to the structural and aerodynamic design principles behind lighter than air systems, along with fundamental fl ight dynamic principles that must be addressed. A prototype design developed by Altaeros Energies is examined as an example of the application of these principles. The chapter closes with suggestions for future research to enable commercially-viable LTA systems. Why Lighter-Than-Air?Lighter-than-air (LTA) technology refers to airborne systems that use helium, hydrogen, or other sources of buoyancy to provide lift. LTA systems include freefl ying blimps, airships, dirigibles, and z eppelins; as well as stationary, tethered systems such as moored balloons or aerostats. For decades, hundreds of large tethered aerostats have been deployed to lift heavy pieces of equipment into the air for long periods of time. Aerostats are the only tethered aeronautical platforms that have consistently demonstrated continuous airborne deployments for over a month at a time without returning to the ground.The concept of using LTA technology for energy generation is almost as old as LTA technology itself, and can be separated into three phases. The fi rst phase was Chris Vermillion ( ) · Ben Glass · Adam Rein Altaeros Energies

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Section: Low-wind To High-wind Flight Transitionmentioning

confidence: 99%

Section: Passive Alignment With Windmentioning

confidence: 99%

Section: Six Degree-of-freedom Model For Shell Dynamicsmentioning

confidence: 99%

Section: Six Degree-of-freedom Model For Shell Dynamicsmentioning

confidence: 99%