Experimental implementation of acoustic impedance control by a 2D network of distributed smart cells

Abstract

New miniaturization and integration capabilities available from emerging microelectromechanical system (MEMS) technology will allow silicon-based artificial skins involving thousands of elementary actuators to be developed in the near future. Smart structures combining large arrays of elementary motion pixels are thus being studied so that fundamental properties could be dynamically adjusted.This paper investigates the acoustical capabilities of a network of distributed transducers connected with a suitable controlling strategy. The research aims at designing an integrated active interface for sound attenuation by using suitable changes of acoustical impedance. The control strategy is based on partial differential equations (PDE) and the multiscaled physics of electromechanical elements. Specific techniques based on PDE control theory have provided a simple boundary control equation able to annihilate the reflections of acoustic waves.To experimentally implement the method, the control strategy is discretized as a first order time-space operator. The obtained quasi-collocated architecture, composed of a large number of sensors and actuators, provides high robustness and stability. The experimental results demonstrate how a well controlled active skin can substantially modify sound reflectivity of the acoustical interface and reduce the propagation of acoustic waves.

Adaptive Metacomposites for Vibroacoustic Control Applications

“…In this section, we present a so-called adaptive acoustic liner made of a distribution of individual cells integrating micro-controller, sensor and actuator, power supply, signal amplification, signal conditioning to control acoustical impedance. The metacomposite has a great merit of being very effective and allows an important attenuation of the acoustic transfer without the necessity of very strong displacements of the membrane interfaces [13]. The last section of this first part shows up the potential of this strategy for modifying noise distribution 3 Smart mechanical metacomposite: how to control absorption and transmission of elastodynamical energy…”

“…The theoretical implementation is validated for annihilating positive reflection of 2D acoustic waves. Its stability and robustness margins are also described in [13].…”

“…The proposed system is made of a periodically distributed set of active cells including one loudspeaker, one microphone, a DSP and conditioning electronics components as depicted in Fig. 2 [13]. The system is also implemented as an active liner in which all individual cells compute the local loudspeaker control signal by using pressure measurement coming from adjacent ones.…”

Coordination and Computation in Distributed Intelligent MEMS

“…Among these two major fields of applications, distributed MEMS are also used in lots of different applications like atomic force microscopes (AFM) arrays [11], boundary layer control either on aircraft (AeroMEMS I and II projects) or on cars (ANR CARAVAJE project), flying drone from Silmach company for example (see Figure 1), and smart dusts [12]. Furthermore, many distributed macro sensor/actuator array like acoustic impedance control [3], see Figure 1, could be applied using diMEMS systems. As it can be seen in these examples, the potential of diMEMS is huge and we think it will give birth to even more new applications as well.…”

Towards Usage of Wireless MEMS Networks in Industrial Context

“…Furthermore, many distributed macro sensor/actuator arrays like active noise cancellation [27] could be applied using MEMS systems.…”