Dual-Path Rail Brake Control for Safe Failure-Tolerant Braking
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Solution Overview
Problem
Existing brake systems for rail vehicles, such as pneumatic and electrodynamic systems, face challenges in balancing safety integrity levels, system availability, and flexibility, with pneumatic systems requiring extensive infrastructure and electrodynamic systems being dependent on electrical subsystems for functionality, and existing electromechanical systems being inflexible and prone to complete system failures.
Innovation Solution
A brake system with dual braking paths, one with low safety integrity for normal operation and another with high safety integrity for critical situations, allowing seamless switching between paths to ensure reliability and flexibility, utilizing shared functional parts and an internal power supply for redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pneumatic brake systems are used, then reliability and availability are improved, but device complexity and infrastructure requirements increase
Solution Approach 1:
The brake system is divided into two independent braking paths: a first braking path with low safety integrity for normal operation and a second braking path with high safety integrity for critical situations. This segmentation allows each path to be optimized independently, reducing overall system complexity while maintaining reliability through the second path as a dedicated safety backup that does not require extensive pneumatic infrastructure.
2Device complexity
If electrodynamic brake systems are used, then device complexity is reduced, but reliability decreases due to dependency on electrical subsystems
Solution Approach 1:
The safety-critical braking function is extracted from the electrical subsystems and implemented as a separate second braking path with its own dedicated power supply unit. This extraction ensures that the safety function does not depend on the electrical subsystems, maintaining reliability even when electrical systems fail, while the first braking path handles normal operation with simpler infrastructure.
3Device complexity
If electromechanical brake systems are used, then device complexity is reduced, but adaptability decreases due to inflexible actuation characteristic
Solution Approach 1:
The brake control unit dynamically switches between the first and second braking paths based on the operational situation and safety requirements. The system can flexibly allocate braking force between the two paths and adjust the safety integrity level as needed, providing adaptability without requiring complex infrastructure, as the switching logic is managed electronically rather than through complex mechanical arrangements.
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
The system provides high availability and safety integrity, decoupling the need for extensive infrastructure and ensuring continuous operation even in the event of component failures, maintaining safe and flexible braking functions.
Implementation Method 1
The friction generated by contact pressure is converted into thermal energy, thereby decelerating the rail vehicle
Data Source
AI summary
A device and method for electromechanically braking rail vehicles, wherein the brake system includes a brake control unit configured to provide braking functions and output a force manipulated variable, an actuator control unit configured to provide functions for generating a frictional braking force based on the force manipulated variable and to output an actuation variable, a braking force unit configured to provide functions for generating a frictional braking force based on the actuation variable, a first braking path from functions that are active between control inputs by the brake system and the generation of a braking force, and a second braking path from functions that are active between control inputs by the brake system and the generation of a braking force.