Research And Design Of Active Control System On Special Vehicle

The hazards of interior noise in special vehicle have attracted great attention of relevant departments. Using the technology of active noise control to improve the interior environment is a subject of great significance. The existing active noise control system stays in the simulation stage, and it’s difficult to achieve the design requirements. The algorithm, which needs to get the exact model of secondary-path, is a serious obsracle to the application of the active noise control algorithm. In view of the above problems, the work of this paper mainly from the following aspects:Firstly, according to the defects of LMS adaptive algorithm which is applied to the simulation experiment, we improve the traditional LMS algorithm, and apply the FX-LMS algorithm to build an adaptive feedforward active noise control system. We use the reference noise signal filtered by secondary-path to avoid the delay due to the secondary-path. And we analyze the factors that affect the performance of the FX-LMS algorithm, and the system can achieve better stability and noise reduction in suitable parameters.Secondly, taking into account the dependence on the secondary path model in most active noise control algorithms, this paper proposes a adaptive model-free control method based on the simultaneous perturbation stochastic approximation algorithm, based on the study of domestic and foreign scholars’s research on active noise control algorithms about no secondary-path modeling, and solves the problems of uncertainty about the secondary path.Considering the layout of the secondary sound and error microphone has great effects on the noise reduction of the active noise control system, in order to use less number of secondary sound to obtain better de-noising effect and larger noise reduction space, this paper researches the layout strategy of the secondary sound and error microphone based on the closed space within the active noise control system as an example, and it is led to the influence law of the actual effect of noise reduction about the layout of the secondary sound and error microphone in the active noise control system, and put forward the feasible scheme on this basis.This paper also validates the adaptive ANC algorithm based on no secondary-path modeling and the layout strategy of the secondary sound and error microphone in the perspective of system implementation. Experiments have shown that the active noise control system can effectively reduce noise within the enclosed space, and has better system stability.