Design of robust nonlinear autopilot for helicopters with handling quality requirements

具有操控质量要求的直升机鲁棒非线性自动驾驶仪设计

• 批准号: 138416-2007
• 负责人: Akhrif, Ouassima
• 金额: $ 1.55万
• 依托单位: École de technologie supérieure
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=391507
• 关键词: Design; robust; nonlinear; autopilot; helicopters

Helicopters are required nowadays to possess high levels of agility and maneuverability and the capability to operate in degraded visual conditions over a wide range of airspeeds. Furthermore, for certification purposes, they need to satisfy some stringent reliability and performance requirements (the so-called handling qualities, HQ's) set out by the US Army's Aeronautical Design Standard ADS-33 (more precisely ADS-33E-PRF). From the control engineer point of view, designing helicopter flight control laws is a very challenging problem: Helicopters present highly nonlinear and fully coupled dynamics that are inherently unstable. Existing mathematical models vary greatly from one flight region to the other and present severe uncertainties due to the empirical representation of aerodynamic forces and moments. Still, for most rotorcraft flying today, the control laws have been developed using predominantly classical single-loop frequency response and root locus design techniques. These techniques are based on linearized models about a set of trim points within the flight envelope and provide only local stability. Moreover, the cost and time associated with refining the flight control law for each trim point and then «stitching them together» with gain schedules to cover the full flight is substantial and there is still much room for improvement in achieving consistent HQ's in the extreme portions of the flight envelope. This research proposes to develop a nonlinear autopilot which does not rely on small signal approximation nor on gain scheduling and is based on recent results on nonlinear adaptive regulation. It is capable of achieving accurate tracking for vertical/lateral and longitudinal dynamics in the presence of severe uncertainties. More importantly, we propose to investigate means to integrate ADS-33-based requirements in the autopilot design. The design will be validated on two platforms: a MIMO Twin Rotor system resembling a helicopter available in our laboratory and HELISIM, an industry standard flight simulator for helicopters developed by the Quebec-based company Engenuity Inc.

如今，直升机需要具有高度的敏捷性和机动性，并能够在各种空速范围内在退化的视觉条件下操作。此外，为了认证的目的，它们需要满足美国陆军航空设计标准ADS-33(更准确地说是ADS-33E-PRF)规定的一些严格的可靠性和性能要求(所谓的操纵质量，HQ)。从控制工程师的角度来看，设计直升机飞行控制律是一个非常具有挑战性的问题：直升机呈现出高度非线性和完全耦合的内在不稳定的动力学。现有的数学模型从一个飞行区域到另一个飞行区域差异很大，并且由于气动力和力矩的经验表示而呈现出严重的不确定性。尽管如此，对于今天飞行的大多数旋翼机来说，控制律的开发主要使用了经典的单环频率响应和根轨迹设计技术。这些技术是基于关于飞行包线内一组配平点的线性化模型，并且只提供局部稳定性。此外，完善每个配平点的飞行控制法，然后将它们与覆盖整个航班的增益表缝合在一起，所涉及的成本和时间是巨大的，在航班包络的极端部分实现一致的总部仍有很大的改进空间。该研究基于非线性自适应调节的最新成果，提出了一种不依赖小信号近似和增益调度的非线性自动驾驶仪。它能够在存在严重不确定性的情况下实现对垂直/横向和纵向动力学的精确跟踪。更重要的是，我们建议研究将基于ADS-33的要求整合到自动驾驶仪设计中的方法。该设计将在两个平台上进行验证：一个是我们实验室提供的类似直升机的MIMO双旋翼系统，另一个是HELISIM，这是总部位于魁北克的Entreity公司开发的直升机行业标准飞行模拟器。