Optimum active noise reduction based on acousticalanalysis in the cabin of an agricultural tractor

摘要

High-speed operation of agricultural tractors causes unpleasant noise for the operatorrndue to engine firing, especially in the low-frequency range. To alleviate this noise, we consider anrnActive Noise Control System effective at the low-frequency range. Constructing ANC systems byrnrepeated trial-and-error experiments requires time and cost. Thus in this study, we examined anrnoptimum ANC system arrangement on an acoustical analysis inside a tractor cabin using the finiternelement analysis. The positions of the control loudspeaker and error microphones were set outside thernsound pressure nodal area at target frequencies. While carrying out the analysis the position of controlrnloudspeaker was changed at intervals of approximately 0.2 m. Based on the arrangement examined byrnthe analysis, the ANC control experiments were carried out using the Filtered-X LMS algorithm. Anrnoverall noise reduction of 14dB was achieved for the optimum arrangement, which is more effectivernthan any other position. Results verified the effectiveness of the optimum ANC arrangement.