Active Acoustic Impedance Mapping Using Mobile Robots

Abstract

In this paper we address the problem of autonomous Impedance Mapping (IM) of an environment using a team of mobile robots. IM of a domain provides the boundary information required to model the sound propagation in the domain. We equip the robots with a speaker and two microphones and utilize the two-microphone reflection method to estimate the normal surface impedance of the boundaries. Specifically, while a speaker robot plays white noise, a listener robot measures the pressure values at two adjacent points next to the sample and uses this data to estimate its impedance. We model the collaborative IM task using Linear Temporal Logic and design motion plans that allow the robots to switch between speaker and listener roles while maintaining desired distances from each other and the samples, and measure the impedance of every boundary segment. We present experimental results and validate our impedance measurements by comparing to a standard method.