Railway Bridge Displacement Estimation with Calibrated Acceleration Signals
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Solution Overview
Problem
Existing methods for estimating deflection amounts in railway bridges inaccurately reduce the original displacement amplitude due to drift and low-frequency components in displacement waveforms, leading to incomplete signal components.
Innovation Solution
A measurement method involving acceleration data acquisition, speed vibration component calculation, and displacement amplitude estimation using a conversion function derived from displacement data, which includes integration and filter processing to accurately determine displacement amplitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If twice integration processing is applied to acceleration data to estimate displacement, then displacement can be calculated from acceleration measurements, but drift and low-frequency components are reduced along with the signal, causing inaccurate displacement amplitude estimation
Solution Approach 1:
The patent segments the displacement estimation process into two distinct parts: (1) a calibration phase using displacement meter data to capture the complete displacement waveform including low-frequency components, and (2) a measurement phase using acceleration data processed through integration and filtering. The conversion function learned in phase 1 compensates for the information loss in phase 2, allowing accurate displacement amplitude estimation without directly applying twice-integration to the final measurement data.
Solution Approach 2:
The patent performs preliminary calibration using displacement meter measurements before actual acceleration-based monitoring. During this calibration phase, the system learns the relationship between acceleration and displacement waveforms, capturing the complete signal including low-frequency components. This preliminary action creates a conversion function that compensates for the inevitable information loss when processing acceleration data through integration and filtering in subsequent measurements.
2Stability of the object's composition
If filter processing is applied to reduce drift in acceleration data, then measurement stability improves, but low-frequency displacement components are also attenuated
Solution Approach 1:
The system performs preliminary calibration using displacement meter data to learn the complete displacement waveform characteristics including low-frequency components before actual monitoring begins. This preliminary action stores the true displacement signal characteristics in a conversion function, which is then used to recover accurate displacement amplitudes from filtered acceleration data, effectively decoupling the need for filtering from the need to preserve low-frequency signal components.
Solution Approach 2:
The patent introduces a conversion function as an intermediary that bridges the gap between filtered acceleration data and true displacement waveforms. This conversion function, learned during calibration using displacement meter measurements, acts as a mediator that compensates for the low-frequency component attenuation caused by filtering, allowing the system to maintain both measurement stability and displacement amplitude accuracy.
Data Source
AI summary
A measurement method includes: an acceleration data acquisition step of acquiring acceleration data output from an accelerometer that observes an observation point of a structure when a first moving body moves on the structure; a speed vibration component calculation step of calculating a first speed vibration component by performing integration processing and filter processing on an acceleration based on the acceleration data; and a displacement amplitude estimation step of estimating, based on the first speed vibration component and a conversion function calculated in advance based on displacement data output from a displacement meter that observes the observation point when a second moving body moves on the structure, a displacement amplitude of the structure when the first moving body moves on the structure.