Multi-Turn Magnetic Sensor Reset for Mid-Range Rollover Counting
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Solution Overview
Problem
Multi-turn magnetic sensors face challenges in initializing and resetting to a mid-position within their measurement range and are limited by the physical geometry of their magnetic spirals, preventing continuous counting beyond a certain number of turns.
Innovation Solution
A multi-turn magnetic sensing system utilizing two magnetic sensors, one clockwise and one counterclockwise, with domain walls propagating in opposite directions, allows for mid-range reset and rollover counting by applying a magnetic field to reset the sensors to a state between maximum and minimum turn counts, enabling continuous tracking of magnetic field rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single multi-turn magnetic sensor is used, then the device complexity is low, but the measurement range is limited by the physical geometry of the magnetic spiral
Solution Approach 1:
The measurement system is segmented into two separate multi-turn magnetic sensors, each with its own magnetic spiral. The first sensor covers a first range of rotations while the second sensor covers a second range of rotations. By combining the output signals from both sensors, the system achieves a total measurement range that exceeds what a single sensor could provide, thus resolving the contradiction between device complexity and measurement range.
Solution Approach 2:
The patent extends the measurement capability from a single-dimensional range (one sensor) to a multi-dimensional range (two sensors with different rotational ranges). The first magnetic spiral is configured for a first range of rotations and the second magnetic spiral is configured for a second range of rotations, creating an extended measurement space that resolves the limitation of physical geometry.
2Productivity
If the sensor is reset to a mid-position, then continuous counting beyond physical limits is enabled, but the initialization process becomes more complex
Solution Approach 1:
A magnetic reset field is introduced as an intermediary mechanism to reset the domain walls in the magnetic spirals to a predetermined mid-position state. This external magnetic field acts as a mediator that can initialize both sensors to a known state without requiring complex mechanical or electronic reset mechanisms, thereby enabling continuous counting while managing the complexity of the reset process.
3Measurement precision
If two multi-turn magnetic sensors are used with opposite domain wall propagation, then rollover counting and extended range are achieved, but the device complexity increases
Solution Approach 1:
The patent merges the output signals from two separate multi-turn magnetic sensors through a decoder to produce a combined turn count that reflects the total number of rotations. The first sensor and second sensor are combined such that their respective measurement ranges overlap and complement each other, achieving extended measurement precision and rollover counting capability while managing system complexity through signal integration.
Solution Approach 2:
The decoder processes the output signals from both sensors with feedback mechanisms to determine the correct turn count state. By monitoring the states of both sensors and applying logic to resolve ambiguities and determine the absolute number of rotations, the system achieves high measurement precision while managing the complexity of having two sensors through intelligent signal processing.
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
Enables continuous counting of magnetic field rotations beyond the physical limit of individual sensors by using a mid-position reset and rollover counting mechanism, ensuring accurate tracking of both clockwise and counterclockwise rotations with improved resolution and range.
Implementation Method 1
A magnetic sensing system can include a multi-turn magnetic sensor that counts a cumulative number of rotations of a magnetic field. 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
In the multi-turn magnetic sensing system, 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 related methods. A system can include a first multi-turn magnetic sensor and a second multi-turn magnetic sensor, in which 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. A decoder can output a turn count that is based on states of the first and second multi-turn sensors. The first and second multi-turn sensors can have a reset state that corresponds to the turn count having a value between minimum and maximum values of a counting range relative to the reset state.