Railway Bridge Deflection Measurement With Variable-Passband Filtering
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Solution Overview
Problem
Existing deflection measurement methods for railway bridges fail to accurately estimate original displacement amplitudes due to damping of low-frequency components and drift, leading to inaccurate deflection measurements.
Innovation Solution
A measurement method and apparatus that includes acquiring observation data, calculating the fundamental frequency of deflection, performing filter processing with a variably set passband, and integrating the data to generate accurate displacement measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If double integration is performed on acceleration data to estimate bridge deflection, then displacement can be calculated, but drift and noise in low-frequency components cause inaccurate displacement amplitude estimation
Solution Approach 1:
The patent applies preliminary zero-point correction to acceleration data before integration processing. By correcting the zero point of acceleration when the bridge is in an unloaded state and applying this correction to loaded state data, the method eliminates drift components that would otherwise accumulate during double integration, thereby improving displacement amplitude estimation accuracy
Solution Approach 2:
The patent dynamically adjusts the passband of the filter based on the fundamental frequency of bridge deflection. By variably setting the passband according to the calculated fundamental frequency, the filter effectively removes noise components while preserving the signal components, preventing amplitude attenuation and improving measurement precision
2Reliability
If a fixed passband filter is used to reduce noise, then drift can be suppressed, but signal components in the low-frequency range are dampened along with drift
Solution Approach 1:
The patent makes the filter passband dynamic by setting it based on the calculated fundamental frequency of bridge deflection. This allows the filter to adapt to different operating conditions and frequency characteristics, suppressing drift and noise while preserving signal components, thereby preventing amplitude attenuation and improving both reliability and measurement precision
Solution Approach 2:
The patent changes the filter parameters (passband) based on the fundamental frequency calculation. By adjusting the passband parameter dynamically according to the bridge's fundamental frequency, the filter effectively distinguishes between drift components and signal components, allowing drift suppression without dampening the original displacement amplitude
Data Source
AI summary
A measurement method includes: an observation data acquisition step of acquiring observation data output from an observation apparatus that observes an observation point of a bridge, the observation data including a response to an action of a railway vehicle traveling on the bridge on the observation point; a fundamental frequency calculation step of calculating, based on first measurement data based on the observation data, a fundamental frequency of deflection repeatedly generated at the bridge due to the traveling of the railway vehicle; a filter processing step of performing filter processing on the first measurement data using a filter having a passband variably set according to the fundamental frequency to generate second measurement data; and an integration processing step of performing integration processing on the second measurement data to generate third measurement data.