Sasidharan Anoop, Velamati Ratna Kishore, Mohammad Akram, Benaissa Sabrina
Department of Electrical and Electronics Engineering, Amrita Vishwa Vidyapeetham, Amritapuri, India.
Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Coimbatore, India.
Sci Rep. 2024 Feb 14;14(1):3697. doi: 10.1038/s41598-024-53851-1.
Lighter-than-air (LTA) aerial vehicles such as airships and aerostats can be found in various strategic and commercial applications, primarily due to their capability to hover and stealth. The mathematical model of these vehicles helps in understanding their complex dynamics and designing and developing proper stabilisation systems for them. Stability derivatives have been used for developing mathematical models for heavier-than-air aerial vehicles since their introduction. This paper presents a methodology to develop a mathematical model of an aerostat based on stability derivatives. One of the major contributions of this study is the estimation of aerostat's added mass terms expressed as longitudinal stability derivatives due to acceleration of the longitudinal motion variables. A longitudinally decoupled linear mathematical model of a single-tethered aerostat using stability derivatives is investigated in this study. A computational fluid dynamics (CFD)-based analysis of the 3D model of the vehicle is used to obtain the stability derivatives. The methodology presented considers the aerostat and tether models separately before coupling them to create the full model. The stability derivative analysis is carried out using ANSYS Fluent, and the coupled tethered aerostat model is investigated using MATLAB 2020. The negative pitch angle of the aerostat is caused by the selection of the pitching centre as the aerostat centre of volume instead of the tether confluence point. The tension force on the tether, which is proportional to the wind velocity, and aerostat velocity components are found to be stabilised within 200-400 s.
诸如飞艇和气艇之类的轻于空气（LTA）飞行器可用于各种战略和商业应用，主要是因为它们具有悬停和隐身能力。这些飞行器的数学模型有助于理解其复杂的动力学特性，并为它们设计和开发合适的稳定系统。自引入以来，稳定性导数一直用于开发重于空气的飞行器的数学模型。本文提出了一种基于稳定性导数开发气艇数学模型的方法。这项研究的主要贡献之一是估计了气艇由于纵向运动变量的加速度而表示为纵向稳定性导数的附加质量项。本研究研究了使用稳定性导数的单系留气艇的纵向解耦线性数学模型。使用基于计算流体动力学（CFD）的飞行器三维模型分析来获得稳定性导数。所提出的方法在将气艇和系留模型耦合以创建完整模型之前分别考虑它们。使用ANSYS Fluent进行稳定性导数分析，并使用MATLAB 2020研究耦合的系留气艇模型。气艇的负俯仰角是由于选择俯仰中心作为气艇的体积中心而不是系留汇合点造成的。发现系留上的拉力与风速成正比，并且气艇速度分量在200 - 400秒内稳定下来。
