Wave-Domain Near-Field Acoustic Error Sensing Strategy for Active Control of Radiated Sound in a Free Space

The challenges of near-field acoustic error sensing lie in the measurement of the total radiated sound power and the optimization of error sensor configuration which depends on the information of secondary sources configuration. The wave-domain strategy is proposed. In the background of the global control of radiated sound in a two-dimensional free space, the active control cost function is formulated in the cylindrical harmonic domain using the exterior sound field reproduction theory with higher order microphones as error sensors. The equivalence with the minimization of the acoustic power is indicated by deriving the optimal secondary source strengths expression. Optimal configuration parameters of error sensors are investigated via simulations. Under the circumstances of the same electroacoustic device configuration, performances of the proposed strategy are compared with those of the conventional pressure matching strategy. Results show that better attenuation levels and system performances are obtained when error sensors and secondary sources are very close. In addition, the proposed strategy decouples the configurations of error sensors and secondary sources, which simplifies the optimization of error sensor configurations.