| After decades of development,active noise control has formed a complete basic theoretical system,and established a mature system implementation method,which has brought the hope to solve the problem of radiated noise control in low frequency band.The active control of ship radiated noise is mainly to track the radiation noise spectrum of the noise source,and use the active control algorithm to generate the required signals.The sound signal is emitted via the secondary sound source to cancel the interference of the radiation field of the primary sound source.Play a role in reducing radiation noise.FxLMS algorithm is mostly used for active feedforward control,but FxLMS may not be stable when the real secondary path transfer function is different from the secondary path model constructed by computational estimation.In this paper,the underwater elastic structure is taken as the research object.An active control algorithm without considering the secondary path is adopted.The reference signal and the error signal are sub-band decomposed,the type of reference signal of each subband is determined and the update direction of the subband is searched.Then the full-band adaptive filter coefficients are directly updated to realize the active noise control.The feasibility and validity of the proposed algorithm are validated for different primary sound sources.The system is simple in structure and easy to implement.Finally,using TI's TMS320F28335 DSP chip to design a single-channel adaptive active controller.The controller is used to build an adaptive algorithm test system and an algorithm program based on the chip is prepared.A single-layer cylindrical shell is chosen as the experimental model.Under free-field conditions,underwater noise reduction experiments are carried out.The experimental results verify the effectiveness of the proposed simplified sub-band non-secondary path control algorithm,the controller can meet the requirements,and the whole system has a certain noise reduction effect. |
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