Railway Vehicle Speed Control Using Sensor Fusion
Solution Overview
Problem
Current railway vehicle movement security systems rely on sophisticated odometric functions that require safety margins due to wheel sensor sensitivity to skidding or jamming, leading to reduced performance and increased errors in distance calculation.
Innovation Solution
A method and system utilizing a controller connected to wheel and acceleration sensors to determine reliable instantaneous speed and calculate maximum permitted speed curves based on distance or time, ensuring accurate odometry and minimizing safety margins by detecting skidding or jamming conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wheel sensors are used to measure speed for odometry, then speed information is obtained, but measurement precision deteriorates due to wheel slippage or skidding
Solution Approach 1:
The patent combines data from multiple sensors (wheel sensors, acceleration sensors, and optionally GPS) to determine train position and speed. By merging these different measurement sources, the system compensates for the imprecision of wheel sensors during slippage or skidding events, maintaining both reliability and measurement precision simultaneously
Solution Approach 2:
The patent introduces an intermediary processing system that evaluates the reliability of wheel sensor data by comparing it with acceleration sensor data. When wheel slippage is detected, the intermediary system switches to using acceleration-based position calculation, thereby mediating between the unreliable wheel sensor and the final position output
2Reliability
If safety margins are added to position values to ensure safety, then reliability improves, but productivity deteriorates due to reduced system performance
Solution Approach 1:
The patent dynamically adjusts the safety margins based on the detected reliability of speed measurements. When wheel slippage is detected, the system increases safety margins temporarily; when measurements are reliable, it reduces margins. This dynamic adjustment maintains safety while optimizing system performance and reducing unnecessary conservatism
Solution Approach 2:
The system changes the parameter of safety margin size based on the operational conditions and measurement reliability. By modifying this parameter dynamically rather than using a fixed conservative value, the system achieves both high reliability and improved productivity
3Measurement precision
If sophisticated odometric functions are implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent segments the odometry function into multiple independent calculation paths (wheel-based, acceleration-based, and optionally GPS-based). Each segment handles specific conditions, and the system selects the appropriate segment based on reliability assessment. This segmentation achieves high precision without requiring one extremely complex monolithic system
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
This approach enhances the accuracy of distance calculation and reduces safety margins, thereby improving the performance and safety of railway vehicle movement security systems by providing reliable speed and distance data for precise control.
Implementation Method 1
at least one acceleration sensor whose sensitivity axis is parallel to the direction of the track
Data Source
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Figure 5~8
AI summary
The method involves receiving output values of one or more wheel sensors (1060), and receiving output values of acceleration sensors (1065), where an acceleration value is determined from the output values of the acceleration sensors. The output values of the wheel sensors are used for supervision of a railway vehicle i.e. train in accordance with a comparison (1070) of the acceleration value with a reference acceleration value. An instant speed of the train is determined from the received output values of the wheel sensors and the acceleration sensors. Independent claims are also included for the following: (1) a system for securing a movement of a railway vehicle on a track (2) a railway vehicle.