Origami-Inspired Adaptive Acoustic Tank for Optimal Reflection Mitigation

The periodic calibration and testing of acoustic sensors, often involve extensive measurements in acoustic tanks. These are usually small facilities whose boundaries are covered with phono-absorption material to suppress reflections. The characteristics of such tanks are defined by the design of absorption planes and the choice of phono-absorption material. Since these characteristics are fixed, an acoustic tank may suppress reflections only for a certain frequency range and setup of the acoustic sensors within the tank, thereby limiting the applications supported by the tank. In this paper, we describe a novel design of an acoustic tank whose absorption characteristics are made adjustable. Inspired by Origami paper folding, this is achieved by changing the shape of the absorption plates with a single degree of freedom. Performing channel estimation between a projector and hydrophone for a required frequency range, the adjustment of the plates involves an iterative genetic-based optimization that finds the best Pareto front to maximize reflection mitigation. We report results from a prototype we contracted that shows a fast convergence of the tank to the best reflection suppression for frequency ranges of 20-30kHz and 35-40kHz. The outcome is an acoustic tank that adapts to various tested frequency ranges and setup of sensors, and can thus improve productivity of acoustic sensor calibration and testing in an efficient manner.