Computational and experimental demonstrations of the hybrid control concept of vibration and noise on helicopters

直升机振动与噪声混合控制概念的计算和实验演示

• 批准号: RGPIN-2015-03857
• 负责人: Feszty, Daniel
• 金额: $ 1.82万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=589428
• 关键词: Computational; experimental; demonstrations; hybrid; control

Reduction of vibration and noise on helicopters is a research priority nowadays in the aerospace sector. Vibration not only deteriorates ride quality, but also increases component fatigue and maintenance costs, it is the main source for chronic back pain and early retirement of pilots and it limits the forward flight speed of helicopters. Noise, on the other hand, negatively affects passenger comfort and the environmental footprint of helicopters. Just as in other engineering fields, vibration and noise are strongly coupled phenomena, since sound waves are generated by vibrating a component (acting like a speaker): the noise source. On helicopters, there are numerous sources of vibration and noise, such as the engine, the gearbox or the tail rotor. However, most of vibration and noise is generated by the main rotor itself through the aerodynamics (such as the appearance of shock waves, dynamic stall, Blade Vortex Interaction, etc.) and dynamics phenomena occurring in blades (such as blade flapping and lead-lag motions). These occur due to the very nature of helicopter flight and are inherently associated with rotor aerodynamics. Although most of noise and vibration originates on the main rotor, production helicopters nowadays feature only fuselage based vibration and noise control technologies, which are usually relatively heavy. Therefore, there is great interest in developing lighter, rotor-based systems, which could tackle vibration and noise at their very source – on the rotor blade itself by individually controlling each blade. There have already been various attempts to develop rotor-based active control systems. Nearly all of them are “flow control” concepts, i.e. they try to alter the aerodynamic forces acting on the blades, such as an actively controlled flap, actively twisted rotor blades, actively controlled trailing edge devices, etc. The problem with these is the need for relatively large actuation power, since they act against the forces creating vibration. Carleton University – on the other hand – has been pursuing a unique and original idea in the past 10 years, the so called “stiffness control” concept of blades, in which the structural response of the blades is to be controlled instead of the aerodynamic forces acting on the blades. Stiffness control is based on the theory of parametric excitation of dynamic systems and promises to use much less power for actuation than flow control system. Another important point to note is that it is very challenging to simultaneously reduce vibration and noise on helicopter rotors. The goal of the research outlined in the proposal is to demonstrate computationally and experimentally that simultaneous reduction of vibration and noise is possible by the unique “hybrid control” concept conceived at Carleton University by Prof. Feszty and Nitzsche. This is based on using two independent control systems: a “stiffness control” and a “flow control”.

降低直升机的振动和噪声是当今航空航天领域的研究重点。振动不仅使乘坐质量恶化，而且增加了部件的疲劳和维护成本，是飞行员慢性背痛和提前退役的主要原因，并且限制了直升机的向前飞行速度。另一方面，噪音会对乘客舒适度和直升机的环境足迹产生负面影响。就像在其他工程领域一样，振动和噪声是强烈耦合的现象，因为声波是通过振动一个部件（像扬声器一样）产生的：噪声源。在直升机上，有许多振动和噪音的来源，如发动机，变速箱或尾桨。然而，大部分振动和噪声是由主转子本身通过空气动力学（如激波的出现、动态失速、叶片涡相互作用等）和叶片中发生的动力学现象（如叶片扑动、前导滞后运动）产生的。这些发生由于直升机飞行的本质和固有的旋翼空气动力学相关。虽然大多数噪声和振动来自主旋翼，但目前生产的直升机只采用基于机身的振动和噪声控制技术，而且通常比较重。因此，人们对开发更轻的、基于转子的系统非常感兴趣，这种系统可以通过单独控制每个叶片来解决振动和噪声的根源-在转子叶片本身。已经有各种尝试开发基于转子的主动控制系统。几乎所有这些都是“流动控制”的概念，即他们试图改变作用在叶片上的空气动力，如主动控制襟翼，主动扭曲转子叶片，主动控制后缘装置等。这些的问题是需要相对较大的驱动功率，因为它们与产生振动的力相反。另一方面，卡尔顿大学在过去的10年里一直在追求一个独特而新颖的想法，即所谓的叶片“刚度控制”概念，即控制叶片的结构响应而不是作用在叶片上的空气动力。刚度控制基于动态系统的参数激励理论，并且保证比流量控制系统使用更少的驱动功率。另一个需要注意的重点是，同时减少直升机旋翼的振动和噪音是非常具有挑战性的。提案中概述的研究目标是通过计算和实验证明，卡尔顿大学Feszty教授和Nitzsche教授提出的独特的“混合控制”概念可以同时减少振动和噪声。这是基于使用两个独立的控制系统：“刚度控制”和“流量控制”。