Active vibration control of trim panel using a hybrid controller to regulate sound transmission

Abstract

NOMENCLATURE C l = closed-loop transfer function e(k) = residual vibration at error accelerometer p(R,θ,φ) = farfield sound pressure Tr (R f ) = trace of auto-covariance matrix of filtered-x signal W k = adaptive feedforward controller w = panel acceleration η = convergence factor This paper presents a method for actively controlling the sound transmission through an aircraft trim panel using a hybrid feedforward/feedback control technique. The method involves measuring the frequency transfer function of the trim panel system and then creating an autoregressive moving average model using frequency domain curve fitting. The control technique is designed to minimize the vibration of a panel that has a limited piston-like motion. The hybrid controller consists of an adaptive feedforward controller that operates in conjunction with a linear quadratic Gaussian feedback controller. The feedback controller increases the damping capacity of the secondary plant to augment the convergence rate of the adaptive feedforward controller. Experimental results indicate that the hybrid controller effectively reduces the vibration of active trim panels and therefore also reduces the sound transmission of the panel.

Vibro-acoustic characteristics of an annular disk with narrow radial slots

“…4 with those with Eq. (15). The calculations based on the self and mutual radiation powers match well with the modal expansion technique.…”

“…For the case of a uniform annular disk case, Eq. (15) suggests that coupling could exist between any two (m, n) modes. Thus, define the sound power generated by the coupling between the (m i n i , q i ) mode and (m j n j , q j ) mode as: 13…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Also, out-of-plane (flexural) vibration is a major source of sound radiation from many mechanical, electrical or structural components having annular or circular disk shape. In many cases, intentional or unavoidable asymmetries in the geometry are introduced and these asymmetries substantially alter the vibration of plates along with sound radiation due to the vibration.…”

Experimental Model Predictive Vibration Control

“…An LQ controller has been implemented on the demonstration device to serve as a basis of comparison for the damping effect and timing properties of MPC strategies. The saturated LQ control strategy is often preferred by researchers [13,17,26,33,34,44,48,63,67] for active vibration control applications, although often ignoring the ultimate effects of saturation on optimality and stability. LQ provides an undeniably good vibration suppression performance, since constraints are respected only by enforcing a software saturation limit and possibly a hardware limit setting at the amplifiers.…”