Magnetic Sensor Direction Detection Using Multi-Level Signal Segmentation
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Solution Overview
Problem
Existing magnetic sensors face delays and erroneous detection in determining the moving direction of a magnetic movable due to reliance on a single rise edge of rectangular-wave signals.
Innovation Solution
The magnetic sensor employs a signal forming section that generates signals with multiple levels based on magnetic field changes and a determining section that analyzes the order of these levels to accurately detect the moving direction of the magnetic movable, utilizing both rise and fall edges of rectangular-wave signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If only one rise edge of rectangular-wave signal is used to detect moving direction, then the detection timing is delayed, but the system complexity is kept simple
Solution Approach 1:
The patent segments the rectangular-wave signal into multiple level transitions (rise edges and fall edges) and processes each segment independently through separate comparator circuits. This allows the system to utilize both rising and falling edges for detection, quadrupling the effective detection frequency without requiring complex high-speed processing circuits
Solution Approach 2:
The patent employs periodic action by utilizing both the rising edge and falling edge of each rectangular-wave cycle for detection. Instead of waiting for the next rising edge, the system captures direction information at both transitions, effectively doubling the detection opportunities per cycle. Combined with multiple comparators, this achieves four-fold detection speed improvement
2Reliability
If rectangular-wave signals are used for direction detection, then the circuit is simple, but erroneous detection occurs when magnetic movable is inverted in rotation
Solution Approach 1:
The patent divides the signal processing into multiple independent comparator circuits, each monitoring specific level transitions. This segmentation allows the system to track the sequence of level changes (0→1, 1→2, 2→1, 2→0) and determine direction based on the ordered sequence, eliminating erroneous detection during magnetic movable inversion while maintaining circuit simplicity
Solution Approach 2:
The patent implements feedback through the D-flip-flop circuit that stores the detected direction information and provides feedback to the output transistor. The system continuously monitors level transitions and updates direction detection based on the sequence of changes, ensuring accurate detection even when the magnetic movable inverts rotation by comparing current transitions with stored state
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
This approach enables correct detection of the magnetic movable's direction without significant delay and reduces erroneous recognition, allowing for faster and more accurate determination of the moving direction, nearly four times faster than existing systems.
Implementation Method 1
a sensor section provided opposite to the magnetic movable through a gap and for detecting a change of magnetic field in the gap due to a movement of the magnetic movable
Implementation Method 2
detecting a change of magnetic field caused by the movement of the magnetic movable through the use of a magneto-resistance element
Data Source
AI summary
The magnetic sensor in the invention is arranged to detect a change of magnetic field caused by a movement of the magnetic movable by a magnetic sensor element arranged with a gap to the magnetic movable, to convert the detected change of magnetic field by first and second bridge circuits into electric signals, to generate first and second rectangular-wave signals by first and second comparator circuits depending upon the electric signals, and to form a signal having at least four levels by a signal forming circuit, thereby detecting a moving direction of the magnetic movable depending upon a level-change order in the signal. This makes it possible to detect a rotating direction of the magnetic movable rapidly and correctly.