ACTIVE NOISE CONTROL WITH FXLMS ALGORITHM APPLIED TO A TRACTOR IN DRIVING CONDITION

Tractor drivers are exposed to loud noise at low frequency for a prolonged time, causing discomfort and, in some cases, hearing loss. This paper aims to evaluate the performance of a multichannel active noise control (ANC) system applied to the cabin of a tractor for the reduction of the driver's exposure to noise. The algorithm imple-mented for the generation of the control signals is the classical filtered-X least mean squares (FXLMS) algorithm for a feedforward configuration. The tests are carried out on a tractor with a four-cylinder engine moving on a ring asphalt track in different driving conditions, varying the main parameters determining the motion: the gear, the range and the rotational speed of the shaft. The results show the capability of the ANC system of acting on the first engine components between 80 Hz (limit imposed by the response function of the control loudspeakers) and 700 Hz (limit imposed in the algorithm to reduce the instability induced by the relative oscillations between the control loudspeakers and the error microphones) for different driving conditions.