Rail Brake Actuation with Dual Braking Paths for Fault Tolerance
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Solution Overview
Problem
Existing brake systems for rail vehicles, such as pneumatic and electrodynamic brakes, face challenges in achieving high availability and safety integrity while minimizing system complexity and weight, with pneumatic brakes requiring extensive infrastructure and electrodynamic brakes relying on unreliable electrical systems.
Innovation Solution
A brake system with dual braking paths, one with low safety integrity for service braking and another with high safety integrity for safety braking, utilizing shared mechanical components and electronic controls to switch between paths based on system state, reducing reliance on external infrastructure and enhancing fault tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pneumatic brake systems are used, then high availability and reliability are achieved, but system weight and installation space increase significantly
Solution Approach 1:
The patent extracts and eliminates the pneumatic compressor and air supply infrastructure from the brake system. The electrodynamic brake unit generates braking force directly through electromagnetic interaction between the brake disk and brake shoe, removing the need for compressed air storage and distribution systems that add significant weight and complexity.
Solution Approach 2:
The patent replaces the mechanical pneumatic actuation system with an electrodynamic braking mechanism. The brake control unit electronically controls the electrodynamic brake unit to generate braking force, substituting the mechanical compression and release of pneumatic actuators with electronic control of electromagnetic forces.
2Reliability
If pneumatic brake systems are used, then reliable deceleration is provided, but device complexity and infrastructure requirements increase
Solution Approach 1:
The patent removes the complex pneumatic infrastructure including compressors, air reservoirs, valves, and piping from the brake system. This extraction simplifies the overall system architecture while maintaining braking functionality through the electrodynamic brake unit controlled by the brake control unit.
Solution Approach 2:
The brake control unit serves multiple functions: it monitors brake system state, determines braking force requirements, controls the electrodynamic brake unit, and manages the transition between different braking paths. This multi-functional control approach reduces the need for separate specialized components.
3Weight of moving object
If electrodynamic brakes are used, then system weight is reduced, but dependence on electrical system reliability increases
Solution Approach 1:
The patent segments the braking function into two distinct paths: a first braking path using the electrodynamic brake unit for normal operation, and a second braking path using a mechanical brake unit for safety-critical situations. This segmentation allows the system to leverage the weight advantages of electrodynamic braking while ensuring reliability through a fallback mechanical path.
Solution Approach 2:
The patent implements a pre-configured mechanical brake unit as a backup safety path that can be activated if the electrodynamic braking system fails. This beforehand cushioning ensures that braking capability is maintained even if the primary electrodynamic system becomes unavailable, addressing the reliability concern.
4Device complexity
If a single braking path is used, then device complexity is reduced, but adaptability to different operating conditions decreases
Solution Approach 1:
The patent implements a dynamic braking system that can switch between a first braking path (electrodynamic) and a second braking path (mechanical) based on real-time system state and safety requirements. The brake control unit dynamically determines which path to activate, providing adaptability to different operating conditions without permanently increasing physical complexity.
Solution Approach 2:
The patent changes the operational parameters of the braking system by switching between different braking paths based on safety integrity requirements and system state. This allows the system to adapt its braking characteristics and control strategy to match the specific operational context while maintaining a relatively simple physical architecture.
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 reliable, compact, and efficient braking with high safety integrity, enabling dynamic and situation-dependent operation, while reducing weight and maintenance needs, and maintaining equivalent performance to traditional pneumatic brakes.
Implementation Method 1
electrodynamic brake unit which has a function to generate a frictional braking force
Implementation Method 2
The friction generated by contact pressure is converted into thermal energy, thereby decelerating the rail vehicle
Data Source
AI summary
Electromechanically braking rail vehicles is performed using a brake system that includes a brake controller with a first brake control unit providing braking functions and outputting a force manipulated variable, and a first actuator control unit providing functions for generating a frictional braking force based on the force manipulated variable and outputting an actuation variable. An actuator includes a second brake control unit providing braking functions and outputting a force manipulated variable, a second actuator control unit providing functions for generating a frictional braking force based on the force manipulated variable and outputting an actuation variable, and a braking force unit providing functions for generating a frictional braking force based on the actuation variable. First and second braking path are provided from functions that are active between at least one control input by the brake system and the generation of a braking force.