Robust direct acoustic impedance control using two microphones for mixed feedforward-feedback controller

TL;DR

This paper introduces a hybrid acoustic impedance control system combining feedforward and feedback microphones on a loudspeaker, enhancing stability and accuracy despite model inaccuracies through numerical and experimental validation.

Contribution

It proposes a novel impedance control architecture that integrates both feedforward and feedback strategies to improve robustness and passivity in acoustic control systems.

Findings

Enhanced impedance accuracy with combined control approach

Improved stability under model inaccuracies

Validated effectiveness through numerical and experimental results

Abstract

This paper presents an acoustic impedance control architecture for an electroacoustic absorber combining both a feedforward and a feedback microphone-based strategies on a current-driven loudspeaker. Feedforward systems enable good performance for direct impedance control. However, inaccuracies in the required actuator model can lead to a loss of passivity, which can cause unstable behaviors. The feedback contribution allows the absorber to better handle model errors and still achieve an accurate impedance, preserving passivity. Numerical and experimental studies were conducted to compare this new architecture against a state-of-the-art feedforward control method.