Railway Bridge Speed Measurement Using Response Waveforms
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Solution Overview
Problem
Existing railway vehicle speed measurement methods face increased costs and decreased accuracy when vehicles traverse bridges due to the need for laser equipment and weak reflected light, and they fail to accurately measure speed during deceleration or acceleration near stop stations.
Innovation Solution
A measurement method and apparatus using observation apparatuses on bridges to calculate traveling speed functions by acquiring observation data, calculating entry and exit times, and determining speed based on acceleration and environmental data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser light source is mounted on each railway vehicle to measure speed using Doppler signal, then speed measurement can be performed, but cost increases and measurement accuracy decreases when reflected light or scattered light on a bridge is weak
Solution Approach 1:
Instead of mounting measurement equipment on the moving railway vehicle, the patent inverts the approach by placing observation apparatus on the stationary bridge to observe the passing vehicle. This eliminates the need for expensive laser equipment on each vehicle while achieving accurate speed measurement through bridge response waveform analysis.
Solution Approach 2:
The patent introduces the bridge structure as an intermediary medium. The bridge's dynamic response to the passing railway vehicle serves as a mediator that carries information about the vehicle's speed, weight, and passage time, allowing measurement without direct contact or equipment on the vehicle itself.
2Measurement precision
If a measuring instrument is provided at the bridge to measure passage time, then average traveling speed can be measured, but it is not possible to easily measure speed when the railway vehicle enters or exits the bridge during acceleration or deceleration
Solution Approach 1:
The patent performs preliminary analysis by calculating the railway vehicle's acceleration state based on the bridge response waveform characteristics before computing speed. By detecting changes in the waveform pattern that indicate acceleration or deceleration, the system can apply appropriate calculation methods to accurately determine speed even during non-uniform motion.
Solution Approach 2:
The patent changes the measurement parameters from simple passage time to a comprehensive analysis including bridge response waveform characteristics, acceleration detection, and multiple calculation methods. This allows the system to adapt to different motion states (constant speed, acceleration, deceleration) and accurately measure speed in all conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Accurately measures speed functions of railway vehicles decelerating or accelerating on bridges, reducing costs and improving measurement precision.
Implementation Method 1
a measurement method for measuring, using an observation apparatus that observes an observation point of a bridge, a traveling speed function
Data Source
AI summary
A measurement method includes: an observation data acquisition step of acquiring observation data output from an observation apparatus; a passing time calculation step of calculating, based on the observation data, an entry time when a railway vehicle enters one end of a bridge and an exit time when the railway vehicle exits another end, and calculating a time which is a difference between the exit time and the entry time as a passing time; and a traveling speed function calculation step of calculating a traveling speed function when the railway vehicle travels on the bridge based on the passing time, a traveling distance of the railway vehicle during the passing time, a distance between a stop position of the railway vehicle and a position of an end of the bridge closer to the stop position, and a length between a front surface of a leading car and a leading axle of the railway vehicle.