Train Occupancy Detection Using Correction Coil Positioning
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Solution Overview
Problem
The existing Communications-Based Train Control (CBTC) system faces issues with accurate occupancy detection of block sections due to measurement errors in train position, which can lead to incorrect determination of block section occupancy, causing potential train stoppages and operational inefficiencies.
Innovation Solution
An occupancy detection device and method that utilize a correction coil to correct train position measurements, incorporating an acquisition section for determining the train occupancy range, a provisional detection section for initial occupancy assessment, and a detection point passage determination section to confirm occupancy status, ensuring accurate detection of block section occupancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If train position is corrected based on correction coil communication, then measurement precision is improved, but occupancy detection reliability deteriorates due to position shifts causing false occupancy determinations
Solution Approach 1:
The patent applies preliminary action by determining occupancy status before position correction is applied. The ground system determines whether the train occupies a block section based on the train position before correction, then applies the correction. This prevents position shifts from causing false occupancy determinations while still maintaining measurement precision through correction.
2Measurement precision
If train position is corrected backward, then measurement precision is improved, but occupancy detection reliability deteriorates as the train may be incorrectly determined to re-enter a previously exited block section
Solution Approach 1:
The patent determines occupancy status before backward correction is applied. When the train position is corrected backward, the system has already recorded the occupancy status based on the pre-correction position, preventing false determination that the train has re-entered a block section.
3Measurement precision
If train position is corrected forward, then measurement precision is improved, but occupancy detection reliability deteriorates as the train may be incorrectly determined to leave a block section prematurely
Solution Approach 1:
The patent determines occupancy status before forward correction is applied. When the train position is corrected forward, the system has already recorded the occupancy status based on the pre-correction position, preventing false determination that the train has left a block section.
4Reliability
If margin distance is added to train length for occupancy detection, then occupancy detection reliability is improved, but productivity deteriorates due to reduced block section utilization
Solution Approach 1:
The patent replaces the mechanical approach of adding margin distance to train length with an information-based approach using correction coils. By using precise position correction through communication with correction coils, the system can determine occupancy without adding excessive margin distances, thereby maintaining block section utilization while ensuring detection reliability.
Data Source
AI summary
An onboard system transmits a train occupancy range based on a measured train position to a ground system. The ground system provisionally detects the occupancy state of each block section based on the train occupancy range acquired from the onboard system. Exit detection points (Qh, Qr) are set at a position outside each block section. It is determined that the train has left the block section when the entirety of the train occupancy range has passed the exit detection point (Qh, Qr). When the provisional detection result indicates that the detection target block section is not occupied, and it has been determined that the train has left the detection target block section, it is determined that the detection target block section is not occupied.