FREQUENCY-BASED MODELING AND ACTIVE NOISE CONTROL DESIGN FOR ENCAPSULATED STRUCTURES

In the domain of active noise control (ANC), deterministic elements are often intertwined across a wide frequency spectrum. It presents a hopeful remedy for noise reduction in encapsulated structures like cars, airplanes, or trains. Diverging from conventional sound-absorbing materials, ANC adeptly addresses lower frequencies without necessitating substantial mass in the structure. Boasting real-time adaptability, the capacity to identify noise origins, and automatic responsiveness to acoustic environment shifts, ANC emerges as notably attractive for this type of structures. This paper delineates the methodology employed for the establishment of a simulated testing environment for the active noise control algorithm. This encompasses the development of a simulation model using the high-fidelity modeling tools representing a Noise Box, designed to emulate the acoustic environment within an encapsulated structure. From this simulation model, the frequency response of the Noise Box is extracted for the reference, primary and secondary paths. Subsequently, an intricate identification process is undertaken to obtain transfer function coefficients faithfully mirroring the frequency response of the Noise Box. The identification of frequency responses involves an estimation of the transfer function in the residue-poles form, followed by the calculation of the system's impulse response. This method furnishes a robust estimation of the transfer function, encompassing both amplitude and phase aspects.