Steering Column Switching Device Segmentation for Signal Reliability
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Solution Overview
Problem
The digital matrix arrangement in top steering column control assemblies for vehicles can lead to erroneous interpretations of switch states due to stuck switches, posing a security risk, and existing solutions to mitigate this issue, such as using diodes, increase the device's cost.
Innovation Solution
The implementation of separate functional switching blocks connected to distinct signal inputs and outputs of a microcontroller, with the microcontroller configured to detect and identify signal mutations and send diagnostic messages to isolate faulty blocks, thereby reducing misinterpretation without additional electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a digital matrix arrangement is used to increase the number of accessible switches, then the number of switches whose state is accessible to the microcontroller increases, but the risk of erroneous interpretation of switch states due to stuck switches increases
Solution Approach 1:
The patent divides the switching device into at least two separate functional switching blocks, where each block is connected to two signal inputs and two signal outputs of the microcontroller. This segmentation isolates the functionality so that a stuck switch in one block cannot cause erroneous interpretation in another block, resolving the reliability issue while maintaining the digital matrix's ability to access many switches.
2Reliability
If additional electronic elements such as diodes are implemented to prevent signal return and improve security, then the reliability of switch state interpretation improves, but the cost of the device increases
Solution Approach 1:
Instead of adding diodes to every switch connection, the patent segments the switching device into functional blocks with dedicated signal input/output pairs. This structural segmentation provides security against erroneous signal interpretation without requiring additional electronic components like diodes at each switch, thus improving reliability while controlling cost.
3Reliability
If separate functional switching blocks are used to reduce misinterpretation risks, then the reliability of switch state detection improves, but the device complexity increases
Solution Approach 1:
Each functional switching block is designed to be connected to two signal inputs and two signal outputs, allowing each block to handle multiple switch functions universally. This multi-functionality approach reduces overall device complexity compared to having completely separate dedicated circuits for each switch, while still providing the reliability benefits of segmentation.
Data Source
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AI summary
The invention relates to a switching device for motor vehicle column top comprising a microcontroller (1). The latter comprises at least two distinct functional switching blocks (3, 5), each block being linked to two signal inputs (el, e2, e3, e4) and two signal outputs (a, b, c) of the microcontroller (1), a signal output (a, b, c) or a signal input (el, e2, e3, e4) of which is linked solely to a single functional block (3, 5) and comprising four switches (7, 9, 11, 13, 15, 17, 19, 21), each switch (7, 9, 11, 13, 15, 17, 19, 21) being linked to a signal input/output pair of the microcontroller (1) distinct from that of the other three of the same block (3, 5). At least two distinct functional switching blocks (3, 5) share only either one signal output (a, b, c), or input (el, e2, e3, e4) of the microcontroller (1), and the microcontroller (1) is configured so as to deduce from a signal dispatched by at least one signal output (a, b, c) that has passed through at least one functional switching block (3, 5) and has been received at at least one signal input (el, e2, e3, e4), the state of switching of at least one switch (7, 9, 11, 13, 15, 17, 19, 21) of a functional switching block (3, 5).