Multidimensional Active Sound Design And Control For Automobile Internal Sound Quality

Sound quality is a significant field of vehicle acoustics,at the beginning of which,academics studied sound quality from the perspective of irritability reduction and comfort improvement,soon afterwards the multi-dimensional attributes of the perception of car interior sound get more attention.Sound quality can be decomposed into multiple independent dimensions in perceived space,the most common of which are comfort,power and sports,respectively.At present,the frequency components of engine firing order are utilized as the controlled object to reduce the interior noise,though the auditory comfort is promoted to some extent,the corresponding relationship between the interior sound and the motion state of the vehicle is weakened.Moreover,the positive effects of driving interaction are impaired and the diversified needs of users are out of consideration,let alone a few of negative effects.To address the problems mentioned above,the sound quality of interior noise is predicted and designed based on comfort,sense of power and sense of motion in this paper.Furthermore,the relationship between sound quality and design variables is analyzed quantitatively and the method of determining design variables with examples is illustrated.In the end,an active optimal control method for the designed sound quality is proposed,and the research contents are as follows:The model containing comfort,power and sports prediction is established based on the backpropagation neural network,with the data collected form 4 passenger car drivers’ ear noises as evaluation samples and the grouping comparison method to subjectively evaluate the sound quality of the car.What’s more,the three-dimensional active acoustic design strategies and methods are proposed and the target amplitude formula of the adjustment orders are given,as well as the sound quality and the adjustment orders are correlated and the design value is determined by quantifying the relationship between the design variables and the sound quality.The three-dimensional design method are as follows:(1)For comfort,the adjustment order is determined by the fire order and the harmonic order of 2 times and 3 times frequency according to the law of harmony interval in music theory,the amplitude of which is in an arithmetic series.(2)For the power sense,the firing order is employed as the adjustment order,with the amplitude designed to increase linearly with the speed,the design variable of which is the amplitude change rate with the speed.(3)For the motion sense,the adjustment order is determined by the harmonic orders of the firing order 3 times and 4 times the frequency,with the amplitude designed to be close to the fire level.For the designed engine order noise,a narrowband parallel order active sound quality control system based on CFXLMS algorithm is proposed to improve different dimensions of sound quality in this paper and the effectiveness of the method is evaluated by simulation analysis.In the end,the control effects of the three designed sound quality dimensions are verified based on the built experimental equipment,with the driver’s ear-side steady-state and non-steady-state noise utilized as the control object.It can be concluded that the order design and sound quality active control system proposed in this paper can realize the multi-mode selective active control of sound quality in the car,and the score of the controlled sound sample is obviously improved.