Filtering techniques in the dynamic deformation estimation using multiple strains measured by FBGs

This paper investigates the use of filtering techniques such as the Low-pass and Kalman filter in combination with the quasi-static strain-displacement transformation in order to estimate dynamic structural displacement based on noisy strain measurements. Numerical simulations and vibration experiments were performed on simple beam structures under various dynamic loading cases to determine the sensitivity of estimation procedures against model errors and noise disturbance. In the experimental setup the multiplexing ability of fiber Bragg grating (FBG) sensors was used to obtain strain data with high accuracy and low noise level. Estimated displacements in the experiment were verified against laser displacement readings. Depending on the load case the noise-sensitive, quasi-static shape estimation results could be highly improved by applying recursive filtering methods which allow an application of the simple approach even for complex, vibrating structures.