| MEMS BASED BRIDGE MONITORING SUPPORTED BY IMAGE-ASSISTED TOTAL STATION |
| Paper ID : 1367-SMPR |
| Authors: |
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Mohammad Omidalizarandi *1, Ingo Neumann1, Eva Kemkes2, Boris Kargoll3, Dmitri Diener1, Jürgen Rüffer2, Jens-André Paffenholz4 1Geodetic Institute, Leibniz University Hannover, Germany 2ALLSAT GmbH 3Institut für Geoinformation und Vermessung Dessau, Hochschule Anhalt, Germany 4Geodetic Institute, Leibniz Universität Hannover |
| Abstract: |
| In this study, the feasibility of Micro-Electro-Mechanical System (MEMS) accelerometers and an image-assisted total station (IATS) for short- and long-term deformation monitoring of bridge structures is investigated. The MEMS sensors as part of a geo-sensor network are mounted at different positions of the bridge structure. In order to degrade the impact of systematic errors on the acceleration measurements, the deterministic calibration parameters are determined for fixed positions using a KUKA youBot in a climate chamber over certain temperature ranges. The measured acceleration data yields accurate estimates of the modal parameters over short time intervals but suffer from accuracy degradation for absolute position estimates with time. To overcome this problem, video frames of a passive target, attached in the vicinity of one of the MEMS sensor, is captured from an embedded on-axis telescope camera of the IATS of type Leica Nova MS50 MultiStation with a practical sampling frequency of 10 Hz. To identify the modal parameters such as natural frequencies, mode shapes and modal damping for both acceleration and displacement time series, a damped harmonic oscillation model is employed together with an autoregressive model of coloured measurement noise. The AR model is solved by means of a generalized expectation maximization algorithm. Subsequently, the estimated model parameters from the IATS are used for coordinate updates of the MEMS sensor within a Kalman filter approach. The experiment was performed for a synthetic bridge and the analysis shows an accuracy level of sub-millimetre for amplitudes and much better than 0.1 Hz for the frequencies. |
| Keywords: |
| Displacement and vibration analysis, MEMS accelerometer, Image-assisted total station, Modal parameter identification, Adaptive robust estimation, Kalman filter, Bridge monitoring |
| Status : Conditional Accept (Oral Presentation) |
