Magnetic Position Encoding for Fail-Safe Gearshift Detection
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Solution Overview
Problem
Conventional position detection devices for vehicle gearshift levers suffer from false detection issues due to time lags in detection element output switching, leading to unexpected signal patterns when the operation member moves between positions.
Innovation Solution
A position detection device with a detection system comprising 3N detectors, where N is an integer of 3 or more, each with one-bit resolution, configured to switch outputs uniquely between predetermined and N positions, ensuring a minimum Hamming distance of three to detect and correct errors, thereby suppressing false detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional position detection devices use detection elements with output switching, then position detection function is achieved, but time lags cause false detection due to unexpected signal patterns
Solution Approach 1:
The detection system is segmented into multiple independent detection elements (at least three) arranged in specific spatial relationships. Each detection element independently monitors position along different axes or directions, allowing the system to detect position through combined signals rather than relying on a single detection element that switches outputs. This segmentation eliminates the time lag problem by using simultaneous multi-element detection instead of sequential switching.
Solution Approach 2:
The patent introduces an intermediary encoding scheme where detection element outputs are combined through logical operations (AND, OR, NOT) to create unique position codes. Rather than directly using individual detection element outputs as position indicators, the system uses intermediary code generation that combines multiple detection signals, ensuring that each position has a unique code pattern that prevents false detection even when individual elements have timing variations.
2Reliability
If multiple detectors are used to improve fail-safe, then false detection is suppressed, but device complexity increases
Solution Approach 1:
The detection system divides the detection function into multiple independent detection elements, each responsible for monitoring a specific aspect of position. This segmentation allows the system to achieve high reliability through redundancy while maintaining manageable complexity by assigning specific functions to each element and combining their outputs through systematic code generation rules.
Solution Approach 2:
The detection elements and code generation mechanism serve multiple functions simultaneously: they detect position, provide redundancy for fail-safe operation, generate unique position codes, and enable error detection. This multi-functionality reduces overall system complexity by consolidating multiple requirements into a unified detection framework rather than requiring separate systems for each function.
Data Source
AI summary
A position detection device detects a current positon of a operation member among positions including a predetermined position and includes a detection system that includes a part to be detected and 3N magnetic sensors S. The operation member can move to the positions in N (≥3) different directions from the predetermined position. Movement of the operation member between the predetermined position and another position cause outputs from three of the magnetic sensors to be switched. The magnetic sensors of which outputs are switched by a movement of the operation member between the predetermined position and a first position are all different from the magnetic sensors of which outputs are switched by a movement of the operation member between the predetermined position and a second position.