Active control of structures and sound radiation modes and its application in vehicles

Abstract

This paper presents computation of structural sound power and sound radiation modes, combined with structural dynamic equations to obtain the coupling relationship between sound and structures. As a result, the relationship between sound radiation modes of structures and structural vibration modes is established. The influence of the number and position of optimal secondary force sources on control of sound radiation modes is considered. Results show that sound radiation efficiency of sound radiation modes at the first order was more than that of sound radiation modes at other orders. The main diagonal element of coupling matrix between modes and sound radiation impedances was more than elements at other positions. Sound radiation modes at the first order were dominant sound radiation modes. When the number of secondary force sources was 4, the sound radiation power of structures was the lowest. Four force sources were taken as the basis to conduct on the related experiments in the anechoic chamber and compare with the computational result. Their results had a good consistency, which showed that the mentioned theory method was effective. Finally, the control strategy was applied to roofs of the vehicle. Experiments verified that sound pressure level of the driver in the low frequency was obviously improved, which remedied the defect of other optimization strategies for solving noises in the low frequency.

The Time-Optimal Control Problem of a Kind of Petrowsky System

“…Naturally, the optimal control problems of the Petrowsky systems are also studied. Some approaches are discussed to solve the problems about the optimal control of vibration systems [11][12][13][14][15][16][17][18][19][20][21][22][23]. In [11][12][13], the methods of multiplier and operator semigroups are applied to solve the optimal control problems of some general Petrowsky systems.…”

“…In [18], the optimal control of discretely connected parallel vibration beams is discussed by the means of the Galerkin coupled with parameterization. Moreover, the wavelet's approach can be used to solve the optimal control problems of some special kinds of vibration system as in [19][20][21][22][23]. However, the time-optimal control problems of vibration equations are not talked about according to the literatures that we have reviewed.…”

An explicit formula of perturbating stiffness matrix for partial natural frequency assignment using static output feedback

“…Many aspects of the inverse problem of structural and mechanical dynamics have been involved in the research, such as the structural inverse modification, [1][2][3] model updating [4][5][6] and active vibration control. [7][8][9][10][11][12] These cited here are a small part of the literatures published in recent years. In the above research content, the proposed methods have a nice feature, that is, all the unassigned eigenvalues (or unmodified natural frequencies) with the corresponding eigenvectors remain unchanged while a small number of eigenvalues of a structure are assigned to the targeted values.…”

Low-noise structure optimization of a heavy commercial vehicle cab based on approximation model

“…Thus, substantial efforts focus on improving the acoustic comfort of vehicles. [1][2][3] Optimizing low-noise structure to reduce cab interior noise is one of the essential methods to improve market competitiveness. Furthermore, the working environment of the heavy commercial vehicle is complex, abominable, and usually unexpected.…”