Relative Velocity Train Protection Using Dynamic Trajectory
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Solution Overview
Problem
The existing 'soft wall collision' method for train protection does not adequately consider the safety requirements of the whole spatial-temporal position relationship during train running, leading to potential safety risks of rear-end collisions due to differences in performance parameters and initial velocities of preceding and following trains.
Innovation Solution
A relative velocity based train protection method and apparatus that calculates safe spatial-temporal trajectory information for both preceding and following trains using electronic maps and autonomous velocity measurement, ensuring that the following train's position does not surpass the preceding train's at any time, and determining an Emergency Braking Instruction (EBI) velocity to prevent overspeeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the 'hard wall collision' model is used to protect trains from over-speeding by setting the MA endpoint to the rear position of the preceding train, then train safety is ensured (no rear-end collision), but the tracking interval distance becomes relatively large, limiting line transport capacity
Solution Approach 1:
The patent transitions from the static 'hard wall collision' model to a dynamic 'soft wall collision' model where the MA endpoint is no longer fixed at the rear position of the preceding train. Instead, it dynamically adjusts based on the preceding train's velocity and braking process information. The protection point is set at a position before the rear position (position p), calculated using the estimated forward running distance of the preceding train during braking, allowing the following train to operate closer safely.
Solution Approach 2:
The patent changes the key parameter of the MA endpoint position from a fixed value (rear position of preceding train) to a dynamically calculated value based on multiple parameters including preceding train velocity, braking distance, and safe distance margin. The formula d = dbrake2 - dbrake1 + S reflects this parameter change, where the safe tracking interval is adjusted based on the preceding train's braking characteristics rather than using a conservative fixed distance.
2Productivity
If the 'soft wall collision' method is used to shorten train tracking interval by considering relative velocity and braking process information, then line transport capacity is improved, but safety risks of rear-end collisions arise due to not adequately considering the whole spatial-temporal position relationship during train running
Solution Approach 1:
The patent applies preliminary action by calculating the estimated forward running distance of the preceding train during its braking process before the following train needs to react. The protection point (position p) is determined in advance using the formula that incorporates the preceding train's current velocity and braking characteristics, allowing the following train to plan its trajectory proactively rather than reactively.
Solution Approach 2:
The patent implements feedback by continuously monitoring the preceding train's velocity and braking process information, and using this information to dynamically adjust the MA endpoint position for the following train. The system feeds back the calculated safe tracking interval based on real-time conditions, enabling the following train to maintain safety while optimizing its running trajectory.
3Reliability
If the MA endpoint is set at the rear position of the preceding train considering safe distance margin, then the following train can be protected within MA limits, but the tracking interval distance d=dbrake2+S is relatively large
Solution Approach 1:
The patent makes the MA endpoint position dynamic rather than static. Instead of always setting it at the rear position of the preceding train, the system calculates a dynamic protection point (position p) that is forward of the rear position by the estimated forward running distance during braking. This dynamic adjustment reduces the required tracking interval while maintaining protection.
Solution Approach 2:
The patent changes the parameter of MA endpoint position from a conservative fixed value (rear position minus safe margin) to an optimized calculated value. The new position is determined by the formula that subtracts the preceding train's braking distance (dbrake1) from the following train's braking distance (dbrake2) and adds a safe margin (S), resulting in a shorter but still safe tracking interval.
Data Source
AI summary
Provided is a relative velocity train protection method and apparatus. The method includes the following steps: a preceding train and a following train in two successive trains calculate their safe spatial-temporal trajectory information in a stopping process using an electronic map, velocity measurement and positioning information, and performance of the train (S11); the following train obtains the spatial-temporal trajectory information of the preceding train through vehicle-to-vehicle communication (S12); the following train creates a safety condition according to a constraint that a position of the following train does not surpass that of the preceding train at any time, and solves the emergency brake intervention (EBI) velocity of the following train (S13); the following train determines whether its measured velocity v2(t0) exceeds the EBI velocity E2(t0), and if so, make the following train decelerate until the following train stops (S14).