EPB Switching Circuit Failure Detection via Diode Rectification
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Solution Overview
Problem
Existing switching circuits for electric parking brakes (EPB) have numerous failure modes, making failure detection complex and prone to misrecognition of operational states, especially when failures occur.
Innovation Solution
A simplified switching circuit configuration with fewer components and synchronized switch groups reduces failure modes to be detected, using single-pole and three-way switches with diodes to restrict current flow directions and simplify signal control, enabling correct operational state recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switching circuit with many contacts is used to control EPB, then the control functionality is complete, but the number of failure modes increases
Solution Approach 1:
The switching circuit is divided into multiple independent switching units, each handling specific control functions. This segmentation reduces the complexity of the overall circuit while maintaining complete control functionality across all units.
Solution Approach 2:
Each switching unit is designed to handle multiple functions within itself, allowing a single unit to perform what previously required multiple separate contacts. This multi-functionality reduces the total number of failure modes while preserving overall system capability.
2Reliability
If more diodes are added to detect all failure modes, then detection completeness improves, but device complexity increases
Solution Approach 1:
The switching units perform self-diagnosis by monitoring their own operational states. Each unit can detect its own failures without requiring external diagnostic components, eliminating the need for additional diodes while maintaining complete failure detection.
Solution Approach 2:
Each switching unit incorporates feedback mechanisms that continuously monitor its own state and report anomalies. This self-monitoring feedback system enables complete failure mode detection using the existing circuit components without adding extra diodes.
3Measurement precision
If multiple separate switches are used for different functions, then control precision is high, but the number of components increases
Solution Approach 1:
Multiple switching functions are merged into integrated switching units that maintain precise control capabilities. Each unit combines several control functions while preserving the precision required for EPB operation, reducing the total component count.
Solution Approach 2:
Each switching unit is designed as a universal component capable of performing multiple control functions with the same level of precision as dedicated single-function switches, thereby reducing component quantity without sacrificing control accuracy.
4Measurement precision
If a complex switching circuit is used to detect all failures, then detection accuracy improves, but detection time increases
Solution Approach 1:
The switching units continuously monitor their operational states in real-time during normal operation. This preliminary monitoring ensures that when a failure occurs, the system is already aware of the anomaly, eliminating the need for time-consuming post-failure analysis while maintaining high detection accuracy.
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 solution reduces the number of failure modes and detection time, ensuring accurate recognition of the EPB's operational state even during failures, with a simpler configuration and fewer signals required for control.
Implementation Method 1
The first diode is provided to a normally closed terminal of the first switch. The second diode is provided to a normally closed terminal of the second switch. The third diode is provided to a normally closed terminal of the third switch. The fourth diode is provided to a normally closed terminal of the fourth switch. Preferably, the first to fourth diodes are disposed such that all of the four diodes are oriented in the same direction. With this configuration, directions in which currents flow between the terminals are restricted
Data Source
AI summary
A switching circuit includes: an input/output terminal section including four SW terminals; lines connecting between these terminals; switches disposed in paths of the respective lines; and diodes disposed in the paths of the respective lines. The switches are single-pole switches. The diodes are connected to normally closed terminals of the switches, respectively.