Spatial filter design for observation spillover suppression (filter design using the measures of modal observability)

This paper presents generalized design method of a spatial filter for suppressing modal observation spillover. Using singular value decomposition of a modal matrix of the selected modes which is to be suppressed, filter design and optimal sensor placement can be simulteneously computed. This design method is independent on both the number of target modes and the number of sensors. Then the measures of modal observability is developed as criteria for designing the optimal filter in a engineering sense. These measures are related to the amplification rate of each modal coordinate, and hence are useful to select optimal sensor placement for desired filtering. This paper numerically demonstrates the suitability of the proposed technique through its application to a modal filtering of a cantilever beam from a small number of sensor outputs.