Computation of the Added Masses of an Unconventional Airship

Azouz, Naoufel; Chaabani, Saïd; Lerbet, Jean; Abichou, Azgal

doi:10.1155/2012/714627

Cited by 16 publications

(8 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other authors like Refs. [18] and [19] developed frameworks to compute added masses for airships whose shape can be approximated with mathematical expressions. However, due to the recent interest in unconventional airship configurations, and the huge number of developed unconventional configurations, their designers should be provided with better estimates of added masses, thus enabling precise simulations of airship dynamics, which is quite important in the case of complex shapes.…”

Section: Introductionmentioning

confidence: 99%

Added masses computation for unconventional airships and aerostats through geometric shape evaluation and meshing

Tuveri¹,

Ceruti²,

Marzocca³

2014

International Journal of Aeronautical and Space Sciences

View full text Add to dashboard Cite

The modern development in design of airships and aerostats has led to unconventional configurations quite different from the classical ellipsoidal and spherical ones. This new class of air-vehicles presents a mass-to-volume ratio that can be considered very similar to the density of the fluid displaced by the vehicle itself, and as a consequence, modeling and simulation should consider the added masses in the equations of motion. The concept of added masses deals with the inertia added to a system, since an accelerating or decelerating body moving into a fluid displaces a volume of the neighboring fluid. The aim of this paper is to provide designers with the added masses matrix for more than twenty Lighter Than Air vehicles with unconventional shapes. Starting from a CAD model of a given shape, by applying a panel-like method, its external surface is properly meshed, using triangular elements. The methodology has been validated by comparing results obtained with data available in literature for a known benchmark shape, and the inaccuracies of predictions agree with the typical precision required in conceptual design. For each configuration, a CAD model and a related added masses matrix are provided, with the purpose of assisting the practitioner in the design and flight simulation of modern airships and scientific balloons.

show abstract

Section: Introductionmentioning

confidence: 99%

Added masses computation for unconventional airships and aerostats through geometric shape evaluation and meshing

Tuveri¹,

Ceruti²,

Marzocca³

2014

International Journal of Aeronautical and Space Sciences

View full text Add to dashboard Cite

show abstract

“…The added-mass (also called virtual or apparent-mass) forces and torques are aerodynamic reaction efforts from a surrounding fluid on a body which tries to accelerate or decelerate inside it; note that the displaced mass of fluid is accelerated or decelerated together with the body interacting with it (see, e.g., [18,19]). This effect is only relevant if the mass of the displaced fluid is significant compared to the body's mass, which is generally the case for conventional or hybrid airships [20,9,16]. It is also worth noting that it appears even in low-speed and windless conditions.…”

Section: Added Massmentioning

confidence: 99%

“…Despite of the aforementioned advantages of the traditional airships over the HTA vehicles, they suffer from a weak controllability in the vertical and lateral translational degrees of freedom (DOF), besides of being more vulnerable to undesirable aerodynamic effects, such as those due to the drag and the added mass [1]. The interplay between these drawbacks has motivated the design of a number of small and electric hybrid airships [7,8,9,10] provided with an augmented maneuverability by an unconventional combination of actuators. In particular, the reference [7] presents a fin-less ellipsoidal blimp equipped with four vectoring rotors; the reference [8] analyzes a small streamlined blimp actuated by one vertical and two horizontal fixed rotors; the reference [9] is concerned with a flying-wing-shaped hull equipped with four vectoring double rotors; and the reference [10] comes up with a cylindrical blimp with conventional actuators, whose rotor axis can be controlled to slide along a longitudinal keel.…”

Section: Introductionmentioning

confidence: 99%

“…Informally, the above result makes all sense, because since the minimum and maximum values are the only known informaion about the random parameters, the most reasonable choice for their distributions is the one that assigns equal weight to all their possible values.Due to the randomness of and , the air density ρ air and the helium density ρ helium are also random variables [see equation(56)]. Further, since the aerostatic lift [see equation(7)] and the restoring torque [see equation(9)] depend on ρ air and ρ helium , then the translational(14) and rotational(17) dynamic models are rather differential equations with random parameters and, consequently, their variables are stochastic processes. In particular, we choose here the minimum temperature x 1 = 0 o C, the maximum temperature x 2 = 40 o C, the minimum pressure y 1 = 0.7739 atm (at 2000 m and 0 o C), and the maximum pressure y 2 = 1 atm.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Flight control of a hexa-rotor airship: Uncertainty quantification for a range of temperature and pressure conditions

Santos

Cunha

2019

ISA Transactions

View full text Add to dashboard Cite

The present paper is concerned with the dynamic modeling and design of control laws for a small non-rigid multi-rotor airship constituted of an oblate-spheroid helium balloon coupled with an electric-powered hexa-rotor airframe. The vehicle is assumed to operate in windless and lowspeed conditions. A six-degree-of-freedom nonlinear dynamic model is derived for it using the Newton-Euler approach and considering, among other common efforts, a restoring torque due to the displacement of the balloon's center of buoyancy above the vehicle's center of mass and the added-mass effect resulting from the air-structure interaction. Using the derived model and assuming a timescale separation between the translational and rotational dynamics, the attitude and position control laws are designed separately from each other. Both laws are formulated using feedback linearization combined with control input saturation within appropriate parallelepipedal sets, which are carefully chosen to respect pre-defined bounds on the control torque, control force and inclination angle. The effect of temperature and pressure fluctuations is taken into account through a parametric probabilistic approach, where Maximum Entropy Principle is used to construct a physically consistent stochastic model and Monte Carlo method is used as stochastic solver to propagate the uncertainties through the system. Extensive simulation results show the effectiveness of the proposed control system and quantifies the uncertainty of its performance over a wide range of local temperature and pressure.

show abstract

“…[4][5][6] A special focus is done on the computation of added masses especially for unconventional airship. 7 Many important results have been reported on airship control in the past years. For example, Beji and Abichou 8 study the tracking control of a blimp by using a combined integrator backstepping approach and Lyapunov theory.…”

Section: Introductionmentioning

confidence: 99%

Modeling of a heavy-lift airship carrying a payload by a cable-driven parallel manipulator

Abdallah

Azouz

Béji

et al. 2019

International Journal of Advanced Robotic Systems

Self Cite

View full text Add to dashboard Cite

In this article, we present a preliminary analysis of a heavy-lift airship carrying a payload through a cable-driven parallel robot. With unlimited access to isolated locations around the globe, heavy-lift airship enables affordable and safe delivery of heavy cargo thanks to its vertical takeoff and landing capabilities. By considering the airship and the cable-driven parallel robot as a combined system, the kinematic and dynamic models are developed. The choice of the proposed decentralized control structure is justified by the weak coupling of the two subsystems (i.e. airship and cable-driven parallel robot) which makes it possible to control the above two subsystems independently. A robust sliding mode control, capable of auto-piloting and controlling the airship, is developed. Furthermore, an inverse dynamic controller is applied to the cable-driven parallel robot in order to ensure loading and unloading phase. The feature of the proposed control system is that the coupled dynamics between the airship and the cable-driven parallel robot are explicitly incorporated into control system design, without any simplifying assumption. Numerical simulation results are presented and a stability analysis is provided to confirm the accuracy of our derivations.

show abstract

Computation of the Added Masses of an Unconventional Airship

Cited by 16 publications

References 17 publications

Added masses computation for unconventional airships and aerostats through geometric shape evaluation and meshing

Added masses computation for unconventional airships and aerostats through geometric shape evaluation and meshing

Flight control of a hexa-rotor airship: Uncertainty quantification for a range of temperature and pressure conditions

Modeling of a heavy-lift airship carrying a payload by a cable-driven parallel manipulator

Contact Info

Product

Resources

About