Fault Tolerant Solid State Push Button Control System
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Solution Overview
Problem
Current contactless switches employing Hall effect sensors are prone to malfunction, leading to unreliable operation and require improvements in reliability and manufacturing cost-effectiveness while meeting user performance expectations.
Innovation Solution
A contactless switch module incorporating a plurality of magnets, latching magnetic field sensing sensors, and a multi-channel switch controller that allows relative movement between the sensors and magnets, enabling the determination of switch states through sensor states and logic, ensuring reliable operation and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contactless switches with Hall effect sensors are used, then contactless operation is achieved, but reliability deteriorates due to sensor malfunction causing unintended state changes
Solution Approach 1:
The switch controller is divided into multiple independent channel controllers, each monitoring a specific Hall effect sensor. This segmentation allows individual channel monitoring and fault isolation, where a malfunction in one channel does not affect the operation of other channels, thereby improving overall reliability while maintaining manageable complexity through modular design
Solution Approach 2:
The switch controller continuously monitors the output states of Hall effect sensors and compares them against expected states based on actuator position. When a discrepancy is detected (indicating sensor malfunction), the system generates an error signal and can override the faulty sensor's output, providing feedback-based fault tolerance that prevents unintended state changes
2Reliability
If multiple sensors and magnets are used for fault tolerance, then reliability improves, but manufacturing cost increases
Solution Approach 1:
Multiple Hall effect sensors are integrated onto a single printed circuit board along with the control logic and processing circuits. This consolidation reduces the number of discrete components, simplifies assembly procedures, and lowers manufacturing costs while maintaining the redundancy needed for fault tolerance
Solution Approach 2:
The switch controller is designed to handle multiple sensor inputs and perform both normal switching operation and fault detection/diagnosis functions using a single integrated circuit. This multi-functionality eliminates the need for separate diagnostic hardware, reducing component count and manufacturing complexity while achieving reliable fault-tolerant operation
3Ease of operation
If Hall effect sensors are used for contactless switching, then ease of operation improves, but reliability deteriorates when sensors malfunction
Solution Approach 1:
The switch controller continuously monitors Hall effect sensor outputs and anticipates potential malfunctions by comparing sensor states against expected values based on actuator position. When a discrepancy is detected, the system takes preliminary corrective action by overriding the faulty sensor output and generating error signals, preventing unintended state changes before they can occur
Solution Approach 2:
The system implements continuous feedback monitoring where the controller reads Hall effect sensor outputs, validates them against expected states, and adjusts the switch output accordingly. This feedback mechanism ensures that even if a sensor malfunctions, the switch state remains stable and accurate by relying on validated sensor inputs or default states
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 provides a fault-tolerant and reliable contactless switch module that maintains high performance and is economical to manufacture, addressing the limitations of existing contactless switches by accurately determining switch states and preventing unintended state changes due to sensor malfunctions.
Implementation Method 1
latching magnetic field sensing sensors
Data Source
AI summary
A contactless switch module, which is actuatable between a closed circuit position and an open circuit position, a plurality of magnetic field sensing sensors, and a plurality of magnets. The switch also includes a multi-channel switch controller. Each one of the plurality of magnetic field sensing sensors is communicatively coupled to an input channel of the multi-channel switch controller. The multi-channel switch controller is configured to determine a switch state based at least upon the respective states of its input channels.