Active control of sounds, vibrations and fluid-structure interactions

我的研究领域将是主动声控制(ASC)、主动振动控制(AVC)和流固耦合控制(FSI)的设备和控制器的设计。术语控制意味着声音和振动的衰减，但它也可以用来增强振荡。设备上的轴将用于开发一种新的高电平子带声气源(例如，使用压缩空气工作的气动扬声器)，能够在给定载波频率下产生完全可控的时变幅度和相位。挑战将是驱动气动源的瞬时相量，以便产生窄带随机信号。这种气动扬声器的主要实用价值将是在恶劣环境(如涡扇)中衰减高电平窄带声音。这种新的声源还可用于消声器流固耦合的研究、内衬的表征、口部噪声的观测，或用于流体的主动控制。控制器上的轴将集中在多个执行器的命令上，以衰减远场中的压力声，但在执行器的近距离处进行麦克风测量。通常，控制目标将是最小化辐射声功率，该辐射声功率不等于最小化输出功率的标准。目的是开发一种通用的实验方法来学习(或识别)内部模型，该方法将允许使用输出(Y)来控制输入(U)以最小化z的范数。研究将定义该方法的局限性，以便提供关于执行器和传感器的数量和位置以及不确定性影响的指导方针。该方法首先将被限制在谐波信号中。在实际应用中，本文的研究将为多执行器和多传感器ASC/AVC的设计提供依据。因为这将是一种泛型方法，所以它可以转化为活性元材料的设计。FSI的轴线将涉及填充液体的柔性管的振荡(或不稳定)响应的增强或衰减。控制变量为非定常流量，观测变量为顶压。将开发一种实验装置来产生不同的动力学。提出一种灰箱非线性建模方法来辨识非线性模型，并设计观测器。最后，设计极值寻优控制器来增强或减弱系统的不稳定性。这种主动控制FSI的实际主要动机是研究在全液体通风(用可呼吸液体呼吸肺)时，气管在呼气时的塌陷。然而，发展的知识和实验装置将用于其他与类似生理问题相关的研究。

The domain of my research program will be in the design of devices and controllers for active sound control (ASC), active vibration control (AVC) and control of fluid-structure interaction (FSI). The term control means attenuation of sound and vibration, but it also can be used for the enhancement of the oscillation. The axis on the devices will be on the development of a new high level subband acoustic pneumatic source (e.g. a pneumatic loudspeaker working with compressed air) able to generate a perfectly controlled time-varying amplitude and phase at a given carrier frequency. The challenge will be to drive the instantaneous phasor of the pneumatic source in order to generate a narrowband stochastic signal. The main practical interest of such pneumatic loudspeaker will be to attenuate high level narrow-band sounds in harsh environment (e.g. turbofan). Such new source can also be used for the study of the fluid-structure interaction in mufflers, the characterization of liners, the observation of the mouth noise generation, or for active control of fluid. The axis on the controller will focus on the command of multiple actuators in order to attenuate a pressure sound in far field, but with microphone measurements at a close distance of the actuators. Typically, the control objective will be to minimize the radiated acoustic power which is not equivalent to minimize a norm of outpu. The objective is to develop a generic experimental method to learn (or identify) the internal model that will allow to use the outputs (y) to control the inputs (u) in order to minimize a norm of z. The research will define the limitations of the method in order to provide guidelines about the number and the location of actuators and sensors, and the impact of uncertainties. The method will be first limited to harmonic signal. In practical applications, this research will give knowledge for the design of ASC/AVC with multiples actuators and sensors. Because it will be a generic method, it could be translated in the design of active meta-materials. The axis of FSI will concern the enhancement, or the attenuation, of the oscillatory (or unstable) response of a flexible tube filled with a liquid. The manipulated variable is the unstationnary flow rate, and the observed variable is the parietal pressure. An experimental set-up will be developed to generate different dynamics. A grey-box non-linear modeling approach will be developed to identify the nonlinear model, and to design observers. Finally, an extremum seeking controller will be designed to enhance or to attenuate the instability. The practical main motivation for such active control of FSI is the study of the collapse of the trachea during expiration in total liquid ventilation (when the lungs is ventilated with a breathable liquid). However, the developed knowledge and the experimental set-up will be used in other studies related to similar physiological problems.