Railway Secondary Suspension Control Segmentation
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Solution Overview
Problem
The existing electronic control systems for secondary suspensions in railway vehicles are prone to failures due to the use of standard, unreliable IT hardware, leading to frequent loss of control and reduced passenger comfort as the air gap between the axle frame and the body disappears when the computer fails, resulting in the transmission of all bogie accelerations to the body.
Innovation Solution
An electronic control system for secondary suspensions that includes a first calculator to regulate one front and one rear feed valve, with the other valves controlled by a second computer, utilizing bidirectional differential leveling valves to maintain pressure balance between boxes, ensuring continued operation even if the primary computer fails, by connecting the right and left boxes when a pressure difference exceeds a preset value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard off-the-shelf computer components are used for controlling secondary suspension, then the cost is kept reasonable, but the reliability is low due to high failure rate
Solution Approach 1:
The control system is segmented into multiple independent computers, each controlling only specific supply valves (e.g., first computer controls right front and left rear valves, second computer controls left front and right rear valves). This segmentation prevents total system failure when one computer fails, as other computers continue to maintain suspension function.
Solution Approach 2:
The system incorporates automatic differential leveling valves that preemptively compensate for pressure imbalances caused by computer failures. When a computer fails and stops regulating its controlled valves, the differential leveling valves detect pressure differences and automatically equalize them, cushioning against the harmful effect of complete suspension control loss.
2Device complexity
If a single computer controls all supply valves for secondary suspension, then the control architecture is simple, but the system fails completely when the computer malfunctions
Solution Approach 1:
The control architecture is segmented into multiple computers, each responsible for specific supply valves. This distributed control approach maintains relatively simple individual computer functions while dramatically improving overall system reliability through redundancy.
Solution Approach 2:
The system employs automatic differential leveling valves that self-regulate pressure balance without requiring computer intervention. When a computer fails, these valves autonomously detect pressure differences and equalize them, providing self-service compensation that maintains suspension function without complex control architecture.
3Device complexity
If one computer controls multiple supply valves across different bogies, then the number of computers is reduced, but the failure impact is amplified
Solution Approach 1:
The control functions are segmented across multiple computers, with each computer controlling a subset of supply valves. This segmentation limits the propagation of failure effects, as a single computer failure only impacts its controlled valves while other computers maintain their controlled valves and work with differential leveling valves to preserve overall suspension function.
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
This solution maintains passenger comfort by ensuring the air gap is maintained even in the event of a computer malfunction, as the pressure difference is balanced between boxes, preventing the loss of suspension effect and reducing the need for costly hardware upgrades.
Implementation Method 1
a front differential leveling valve fluidly connecting the right and left front boxes when a pressure difference between the right and left front boxes is greater than a predefined difference
Implementation Method 2
Regulating the gas volume V inside a box allows for adjusting the height h between the axle chassis and the body at the level of the box
Data Source
Figure 1
AI summary
The secondary suspension (100) includes: at the front, front right (17) and front left (18) boxes, a front reservoir (111), front right (117) and front left (118) valves supplying the front right and left boxes respectively; and a front differential valve (112) connecting the front right and left boxes; and, at the rear, rear right (27) and rear left (28) boxes, a rear reservoir (211); rear right (227) and rear left (228) valves supplying the rear right and left boxes respectively, and a rear differential valve (212). The electronic control system includes a first computer (224) to regulate one front valve from among the front right and left valves (117, 118) and one rear valve from among the rear right and left valves (217, 218), the other front valve and the other rear valve being controlled by a second computer different from the first computer.