Estimation of structural response using remote sensor locations

A method is presented for estimating the response of a structure during its operation at discrete locations which are inaccessible for measurement using sensors. The prediction is based upon measuring response at other locations on the structure and transforming it into the response at the desired locations using a transformation matrix. The transformation is computed using the system Markov parameters determined from a vibration test in which the response is measured at both the locations which will possess sensors during structure operation and at the desired locations which will not possess sensors. Two different approaches are considered. The first requires as many sensors as there are modes responding in the data. The second approach, a generalization of the first, only requires as many sensors as the number of desired response locations. A numerical example is considered using the Controls-Structures Interaction Evolutionary Model (GEM) testbed at NASA LaRC. Acceleration response with 10% rms noise at six sensor locations is used to predict the response at four force input locations. The proposed method is not computationally intensive, and combined with the fact that the process is causal, may allow real-time applications.