Real-time-controlled artificial quiet channel for acoustic cloaking under varying detection conditions

TL;DR

This paper presents an active acoustic cloaking method that dynamically creates a quiet channel around a moving object, adapting to changing detection signals and object properties in real-time, validated through numerical simulations.

Contribution

It introduces a real-time control algorithm for active acoustic cloaking that adjusts beam direction and wavelength to maintain a quiet zone around a non-stationary object.

Findings

Successful creation of a moving dead zone in simulations

Adaptive control responds to frequency and angle variations

Effective cloaking with minimal back action wave

Abstract

We consider the problem of hiding non-stationary objects from acoustic detection in a two-dimensional environment, where both the object's impedance and the properties of the detection signal may vary during operation. The detection signal is assumed to be an acoustic beam created by an array of emitters, which scans the area at different angles and different frequencies. We propose an active control-based solution that creates an effective moving dead zone around the object, and results in an artificial quiet channel for the object to pass through undetected. The control principle is based on mid-domain generation of near uni-directional beams using only monopole actuators. Based on real-time response prediction, these beams open and close the dead zone with a minimal perturbation backwards, which is crucial due to detector observers being located on both sides of the object's route. The back action wave determines the cloak efficiency, and is traded-off with the control effort; the higher is the effort the quieter is the cloaking channel. We validate our control algorithm via numerical experiments in a two-dimensional acoustic waveguide, testing variation in frequency and incidence angle of the detection source. Our cloak successfully intercepts the source by steering the control beams and adjusting their wavelength accordingly.