Railway Air Brake Abnormality Detection via Virtual Cylinder Pressure
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Solution Overview
Problem
The existing air brake system for railway vehicles faces challenges in accurately determining abnormalities, as the corrected target air pressure may not accurately reflect the driver's operation, leading to potential overlooking of actual issues due to deterioration or failure within the system.
Innovation Solution
A brake control device that includes an instruction value obtaining unit, a cylinder pressure value obtaining unit, and a determination unit, which calculates the difference or ratio between the instruction value and the brake cylinder pressure value, and adjusts for deceleration feedback control to detect abnormalities, even when air pressure is controlled based on the vehicle's state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the target air pressure is corrected depending on deceleration feedback control, then the braking force adapts to the current running state, but the corrected target air pressure does not exactly correspond to the driver's operation, making it difficult to determine abnormalities
Solution Approach 1:
The patent introduces a virtual brake cylinder pressure calculation as an intermediary to bridge the gap between the corrected target air pressure and the driver's operation. By calculating what the brake cylinder pressure should be based on the target air pressure and current running state, the system creates a reference value that accounts for feedback control corrections while still reflecting driver intent, enabling accurate abnormality determination
Solution Approach 2:
The system uses feedback control by comparing the virtual brake cylinder pressure (calculated from target air pressure) with the actual brake cylinder pressure. This feedback mechanism allows the system to adapt to running state changes while detecting abnormalities through the difference between expected and actual pressure values
2Reliability
If the corrected target air pressure is used for abnormality determination, then the system adapts to running state changes, but signs of actual abnormalities may be overlooked due to the correction
Solution Approach 1:
The virtual brake cylinder pressure serves as a mediator that preserves the stability benefits of feedback control while enabling abnormality detection. It translates the corrected target air pressure into an expected pressure value that incorporates running state adaptations, allowing the system to maintain stability without masking abnormalities
Solution Approach 2:
The patent segments the pressure control function into two independent comparison paths: one for normal control (comparing target air pressure with actual pressure for stability) and one for abnormality detection (comparing virtual brake cylinder pressure with actual pressure for anomaly identification). This segmentation allows both stability and detection accuracy to coexist
Data Source
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AI summary
A control device for an air brake device (50) includes an instruction value obtaining unit (86) that obtains an instruction value (A) of an air pressure supplied to an air brake device (50) when braking a railway vehicle (10). The control device further includes a cylinder pressure value obtaining unit (87) that obtains a brake cylinder pressure value (B) calculated from the instruction value (A) through a deceleration feedback control. The control device further includes a determination unit (83) that determines whether there is an abnormality of the air brake device (50) based on a brake efficiency (C) indicating a ration between the instruction value (A) and the brake cylinder pressure value (B).