Vehicle Access Door Redundancy for Sensor Fault Detection
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Solution Overview
Problem
Existing transport vehicle access doors face issues with mechanical push-button detection systems that are prone to electronic failures, hygiene concerns, and inconvenience for users, while contactless sensors suffer from inaccuracies and electronic failures, leading to potential network shutdowns.
Innovation Solution
Implementing a dual detection system with both mechanical and contactless sensors, where a control circuit board integrates a diagnostic unit to analyze the activation states of both systems, identifying malfunctions and providing alerts for predictive maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical push-button detection device is used, then the door can be operated by passengers, but it is prone to electronic failures and hygiene concerns
Solution Approach 1:
The detection system is divided into two independent parts: a mechanical push-button device and a contactless sensor. Each part can function independently, so if one fails, the other can still operate the door. This segmentation resolves the contradiction by maintaining reliability while preserving ease of operation.
Solution Approach 2:
The system changes the detection parameter from purely mechanical contact to include contactless detection modes. The mechanical button provides tactile feedback and reliable activation, while the contactless sensor offers hygiene benefits and alternative operation methods, together ensuring both ease of operation and reliability.
2Ease of operation
If a contactless sensor is used, then hygiene is improved and operation is easier for some users, but it delivers inaccurate information and false detections
Solution Approach 1:
The mechanical push-button device and contactless sensor are merged into a single detection system that processes inputs from both sources. The control unit cross-validates signals from both devices, so false detections from the contactless sensor can be filtered out by requiring confirmation from the mechanical button, thereby improving detection accuracy while maintaining ease of operation.
Solution Approach 2:
The system implements feedback mechanisms where the control unit receives and analyzes signals from both the mechanical button and contactless sensor. When the contactless sensor detects presence, it can trigger the mechanical button or provide confirmation signals, creating a feedback loop that improves detection accuracy by validating contactless detections through mechanical confirmation.
3Device complexity
If only a single detection device is used, then the system is simpler, but it leads to network shutdowns when the device fails
Solution Approach 1:
The system prepares in advance for potential failures by equipping both the mechanical push-button and contactless sensor with diagnostic units that continuously monitor their own functioning. When a failure is detected in one device, the system automatically switches to the other device, cushioning against the impact of failure and maintaining network operation continuity without requiring complex manual intervention.
Solution Approach 2:
When one detection device fails, the system discards its input signals and recovers by relying solely on the functioning device. The diagnostic units identify which device is operational and the control unit adjusts accordingly, allowing the system to continue operating with reduced functionality rather than shutting down, thus maintaining reliability while keeping the overall structure relatively simple.
4Reliability
If both mechanical and contactless detection devices are integrated, then reliability is improved through redundancy, but device complexity increases
Solution Approach 1:
The control unit is designed with multi-functionality, serving both as the primary controller for door operation and as a diagnostic unit that monitors the health of both detection devices. This universal design reduces overall system complexity by eliminating the need for separate diagnostic hardware, while still providing redundancy through the dual detection devices for improved reliability.
Data Source
AI summary
At least one leaf of this door is equipped with a detection device comprising a mechanical detection device and a contactless sensor each capable of detecting a presence. The control circuit board comprises a control unit for movement of each leaf and a diagnostic unit, while means transfer, from the detection device in the direction of the diagnostic unit and the control unit, a first item of information representative of the activation state of the mechanical device, and a second item of information representative of the activation state of the contactless sensor. The diagnostic unit can identify a malfunction at least of the contactless detection device, when the first item of information has an active value while the second item of information has an inactive value. The invention allows redundancy to improve the availability of the detection device, while performing predictive maintenance for the operator, in particular a malfunction of the contactless sensor.