Multi-turn Magnetic Sensor Rollover Counting
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Solution Overview
Problem
Existing multi-turn magnetic sensors face challenges in initializing and resetting at mid-position within the measurement range, and they are limited by the number of turns of their magnetic spirals, preventing continuous counting beyond this limit.
Innovation Solution
The proposed solution involves a multi-turn magnetic sensing system that includes two multi-turn sensors with domain walls propagating in opposite directions, a decoder to determine turn counts, and a magnetic reset mechanism to reset the sensors to a mid-range state, enabling continuous counting and rollover counting beyond the physical limit of the magnetic spirals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multi-turn magnetic sensor uses a fixed number of turns in its magnetic spiral, then the sensor structure is simple and manufacturing is easy, but the sensor cannot count rotations beyond its physical turn limit
Solution Approach 1:
The patent divides the counting function into two independent parts: a magnetic spiral sensor that detects individual turns and a separate electronic counter that accumulates total rotations. This segmentation allows the magnetic spiral to remain physically simple while the electronic system provides unlimited counting capability, resolving the contradiction between structural simplicity and continuous counting versatility.
Solution Approach 2:
The patent implements a nested structure where the magnetic spiral sensor is contained within a larger system that includes an electronic counter and control circuitry. The magnetic spiral's output feeds into the electronic counter, creating a hierarchical nested architecture where the simpler physical sensor is embedded within a more complex electronic counting system, enabling extended functionality without redesigning the entire sensor structure.
2Ease of operation
If a multi-turn magnetic sensor is initialized at the start of its measurement range, then the measurement reference is clear, but the sensor cannot perform mid-range resetting during operation
Solution Approach 1:
The patent transforms the static initialization point into a dynamic reference that can be moved to any position in the measurement range. The electronic counter can be reset to zero at any intermediate position, allowing the measurement reference to adapt dynamically to operational needs while maintaining accurate turn counting from the new reference point, thus enabling mid-range resetting without compromising precision.
Solution Approach 2:
The patent introduces an electronic counter as an intermediary between the magnetic spiral sensor and the final measurement output. This intermediary component handles the complexity of mid-range resetting and turn count calculation, allowing the magnetic spiral to remain a simple position detector while the electronic system manages reference positioning and counting accuracy, thereby enabling flexible resetting without sacrificing precision.
3Adaptability or versatility
If a multi-turn magnetic sensor counts only in one direction, then the sensor design is simpler, but the sensor cannot track rotations in both clockwise and counterclockwise directions
Solution Approach 1:
The patent uses two magnetic spirals wound in opposite directions (one clockwise, one counterclockwise) to detect bidirectional rotations. By inverting the winding direction of the second spiral, the system can differentiate between clockwise and counterclockwise rotations, with each spiral being sensitive to rotations in its respective direction, thereby enabling bidirectional counting capability.
Solution Approach 2:
The patent combines the outputs of two oppositely-wound magnetic spirals with an electronic counter system to create a unified bidirectional counting function. The electronic circuitry merges the signals from both spirals and the index marker detections to calculate total rotations in either direction, consolidating the bidirectional sensing capability into a single integrated system that tracks cumulative rotations regardless of direction.
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 solution allows the multi-turn magnetic sensing system to accurately track cumulative rotations of a magnetic field in both clockwise and counterclockwise directions, overcoming the limitations of physical geometry and achieving continuous counting with mid-range reset and rollover counting capabilities.
Implementation Method 1
A multi-turn magnetic sensor can include magnetoresistive elements that are arranged in series with each other as a spiral shaped strip. Resistance of one or more of the magnetoresistive elements can change in response to rotation of a magnetic field.
Implementation Method 2
Domain walls propagate in an opposite direction in the second multi-turn magnetic sensor relative to the first multi-turn magnetic sensor in response to a magnetic field.
Data Source
AI summary
Aspects of this disclosure relate to multi-turn magnetic sensing systems and methods with rollover counting. In response to a multi-turn magnetic sensor reaching a maximum value, the multi-turn magnetic sensor can be reset and an index value can be updated. A decoder can determine a turn count based on the index value and the state of the multi-turn magnetic sensor. The turn count can have a magnitude greater than a number of turns of the multi-turn magnetic sensor.