Investigation of performance improvements for active reflection control system through 2D time-domain simulation

• We propose 2D time-domain simulation model for the active reflection control.
• The model contains both the electrical control system and the duct acoustic field.
• We provide the design guide of the improved active reflection control system.
• The reflection reduction can be improved to be a satisfactory level of 40 dB.

Active reflection control system is a useful tool to improve the low-frequency performance of the sound absorption coating. However, the reflection reduction level of the previous system is unsatisfactory. It is of great value to evaluate the various factors that may affect the control performance, and to identify the main limitations, which in turn helps to develop an effective control system. For this purpose, the 2D (two-dimensional) time-domain simulation based on the Chebyshev collocation method is exploited to investigate the main influence factors in the control system. The simulation scheme is accurate enough to provide efficient and reliable solutions; in addition, it avoids the defects in experiments, where all the influence factors are mixed together so that they cannot be judged independently. Three factors are chosen to be analyzed one by one, and the design principles to improve the control performance are obtained: the accuracy of the time delay from the reflective surface to the virtual error sensor is the most important one, thus a FIR (Finite Impulse Response) filter should be introduced in the control algorithm, in order to predict an accurate reflected sound pressure; a compromise is required between the good performance and the compactness of the control system.