Railway Speed Control via Time-to-Target-Speed-Crossing
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Solution Overview
Problem
Conventional railway vehicle speed control systems fail to consider braking characteristics, leading to trains exceeding target speeds and resulting in emergency braking due to the free running time and distance before effective braking force is generated, which degrades operation efficiency and increases the frequency of speed limit violations.
Innovation Solution
A speed control system that calculates real-time time-to-target-speed-crossing (TTTSC) using future speed estimation and braking characteristic values to determine appropriate brake outputs, ensuring the train operates within the target speed profile by interlocking the speed control with the calculated TTTSC value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional speed control systems issue braking instructions when train speed exceeds ATO profile, then speed control is performed, but the train continues to run at excessive speed due to free running time before braking force is generated
Solution Approach 1:
The system calculates TTTSC (time to target speed crossing) in advance and issues braking instructions before the train actually exceeds the ATO speed profile. By predicting the future speed trajectory and determining the optimal braking initiation time, the system compensates for the free running time delay, ensuring the train speed is properly controlled when braking force becomes effective.
2Speed
If braking instruction is issued immediately when speed exceeds profile, then response time is reduced, but the train still exceeds ATP speed limits due to braking device characteristics
Solution Approach 1:
The system performs preliminary calculation of TTTSC based on current speed, ATO profile, and predicted future speed. By determining the optimal braking initiation time in advance and issuing instructions proactively, the system achieves both rapid response and efficient operation, preventing speed limit violations without unnecessary early braking.
3Device complexity
If free running distance is not considered in speed control, then control simplicity is maintained, but trains frequently violate speed limits requiring emergency braking
Solution Approach 1:
The system continuously monitors current train speed, compares it with the ATO speed profile, and predicts future speed trajectory. Based on this feedback loop and TTTSC calculation, the system dynamically determines when to issue braking instructions, ensuring speed limit compliance while maintaining controlled system complexity through algorithmic processing.
4Reliability
If braking force is applied late to account for free running time, then speed excess is prevented, but operation efficiency decreases and delays increase
Solution Approach 1:
Instead of delaying braking until the last moment, the system calculates TTTSC in advance and issues braking instructions proactively at the optimal time. This preliminary action ensures that braking force becomes effective exactly when needed to maintain speed profile tracking, preventing both speed excess and unnecessary operation delays.
Data Source
AI summary
The present disclosure relates to a speed control system of a railway vehicle in consideration of a braking characteristic, and more particularly, to a speed control system of a railway vehicle in consideration of a braking characteristic, which calculates in real time a time-to-target-speed-crossing (TTTSC) that is a time required for a speed of a train to exceed a speed of an automatic train operation (ATO) profile through a future speed estimation of the train, and controls the speed of the train to be interlocked with the TTTSC.