Research on the Robustness of Active Headrest with Virtual Microphones to Human Head Rotation

Abstract

The movement and rotation of the human head can significantly degrade the control performance of active headrests with virtual microphones. This paper investigates the performance robustness of an active headrest with virtual microphones against the head rotation in a pure tone diffracted diffuse sound field. A physical model of a headrest system with a diffractive sphere is firstly developed, based on which the influence of acoustic transfer responses on the performance robustness against head rotation is analyzed. Then, the multi-objective optimization with constraints is developed to improve the performance robustness of the system, by designing optimized plant responses. Simulation results show that the method is effective in improving the robustness of single and dual channel systems. For a dual-channel headrest system with the proposed arrangements of secondary sources and microphones, the promotion of the minimum noise reduction is more than 7 dB after optimization when the head rotates from −90 degrees to 90 degrees at 125 Hz, 250 Hz and 500 Hz. In addition, the influence of different parameters on the optimization method is discussed for this dual-channel system. Finally, experiments carried out in an ordinary room validate the effectiveness of the proposed method.