VOLUME VELOCITY ESTIMATION WITH ACCELEROMETER ARRAYS FOR ACTIVE STRUCTURAL ACOUSTIC CONTROL

Controlling the volume velocity of a plate has previously been shown to be a good strategy to reduce its overall sound radiation. Although distributed volume velocity sensors have been developed they have some inherent limitations, particularly the fact that they cannot measure whole-body motion which can have large volumetric components. In this paper, a number of accelerometers are placed on the plate and their outputs are summed in order to estimate the volume velocity. It is found that, by increasing the number of evenly spaced accelerometers, improved estimates of the true volume velocity can be obtained. The number of accelerometers required for a good estimate of volume velocity is also calculated analytically and this value is found to agree with the value found from the simulations. Some further cost functions using accelerometers are also outlined, such as controlling the frequency-dependent shape of the first radiation mode although the results are not very much better then controlling the sum of their outputs. The use of arrays of accelerometers hold some promise for future practical applications of active control as their performance continues to improve and their prices decrease.