Bird-Inspired Gust Soaring for Unmanned Air Vehicles

小型无人机(UAV)的续航能力和耐力目前受到电池容量有限的阻碍。许多无人驾驶飞机的最大飞行时间长达90分钟，这严重限制了它们的用途，并阻碍了它们在灾害响应、遥感(例如用于农业和环境监测)和侦察等领域的好处的实现。通过执行特定的动作来适当地与当地气流相互作用，这些飞行器可以增加它们的势能或空气相对动能(可用于做有用的工作的能量[1])，使它们能够飞得更远、更长；这种能量增加的飞行被称为“飞行”。空气的上升气流构成了飞行的一种条件(即所谓的“静态飞行”)；鸟类可以通过在热力环境中飞行来“顺风车”飞到更高的高度，例如，增加其势能。在风向和强度随时间和空间变化的非均匀风场中，也可以通过利用风梯度来提取能量--这是一种被称为“梯度飙升”的技术。信天翁以在海洋(大气边界层)上方的强风梯度内利用这一技术实现远距离低能耗旅行而闻名。用于利用上升气流和大范围梯度的自动控制系统已经得到了重要的研究，然而，这些能源不适用于无法基本上偏离其期望的飞行路线来利用它们的车辆，例如，由于噪音减少程序或保持在视线之外的要求。可以观察到鸟类在飞行途中通过对随机梯度--例如由建筑物引起的小尺度空间梯度--和阵风(时间梯度)的适当反应来获得能量。这就是我们所熟知的“阵风飙升”。这项研究的目的是开发新的无人机阵风飙升控制算法，以扩大其航程和耐力。这项研究将特别关注城市环境，由于风和结构之间的复杂相互作用，小尺度的空间梯度很常见。

The range and endurance of small unmanned aerial vehicles (SUAVs) is currently hindered by their limited battery capacity. Many SUAVs have a maximum flight time of up to ninety minutes, severely restricting their utility and preventing their benefits from being realised in fields such as disaster response, remote sensing (e.g. for agriculture and environmental monitoring) and reconnaissance. By performing particular manoeuvres to interact with local airflow appropriately, these vehicles can increase their potential or air-relative kinetic energy (the energy available to do useful work [1]), enabling them to fly further and for longer; this energy gain flight is known as 'soaring'. Updrafts of air form one condition for soaring flight (known as 'static soaring'); a bird can gain a 'free ride' to higher altitudes by flying in a thermal, for example, increasing its potential energy. Energy can also be extracted in nonuniform wind fields, where the wind direction and strength change in space and time, by utilising wind gradients - a technique known as 'gradient soaring'. Albatross are famous for exploiting this technique within the strong wind gradients above the ocean (in the atmospheric boundary layer) to achieve long-distance low-energy-expenditure travel. Automatic control systems for exploiting updrafts and large-scale gradients have received significant research, however these energy sources are not applicable for vehicles unable to deviate substantially from their desired flight path to exploit them, due for example to noise abatement procedures or a requirement to keep out of sight. Birds can be observed to gain energy en route through appropriate reactions to stochastic gradients - small-scale spatial gradients, caused for example by buildings, and gusts (gradients in time). This is known as 'gust soaring'. The goal of this research is to develop new gust soaring control algorithms for SUAVs in order to extend their range and endurance. The research will particularly focus on urban environments, where small-scale spatial gradients are common due to the complex interactions between the wind and structures.