Multi-Turn Magnetic Sensor Initialization Without Mechanical Repositioning
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Solution Overview
Problem
Magnetic multi-turn sensors require initialization into a known state with a defined domain wall configuration, which is typically done at the start or end position of the mechanical system, making it impractical for systems where the functional start point is not easily accessible.
Innovation Solution
A method involving the application of a strong magnetic field to fill the sensor with domain walls, followed by a current to a domain wall stopping structure and a rotating magnetic field to achieve the desired domain wall configuration without requiring the mechanical system to be positioned at a start or end point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is initialized at the start or end position of the mechanical system, then the sensor can be set in a known magnetic state, but the mechanical system must be repositioned which is impractical for systems where the functional start point is not easily accessible
Solution Approach 1:
The patent applies preliminary action by using a domain wall stopping structure that is pre-configured to annihilate domain walls at specific locations on the magnetic track. This allows the sensor to be initialized into a known state without requiring the mechanical system to be repositioned to a start or end point, as the stopping structure automatically establishes the reference state during normal operation
Solution Approach 2:
The patent replaces the mechanical repositioning requirement with a magnetic field-based solution. Instead of mechanically moving the system to a start position, an external magnetic field is applied to generate and control domain walls, which are then annihilated by the stopping structure to establish the known magnetic state electronically rather than mechanically
2Reliability
If a strong magnetic field is applied to fill the sensor with domain walls, then the desired domain wall configuration can be achieved, but additional magnetic field control mechanisms are required
Solution Approach 1:
The patent uses an intermediary approach by introducing a domain wall stopping structure as a mediator between the external magnetic field and the magnetic track. The stopping structure receives the magnetic field input and translates it into controlled domain wall annihilation at specific locations, providing precise configuration control without requiring complex direct field generation mechanisms across the entire sensor
Solution Approach 2:
The patent applies local quality by concentrating the magnetic field interaction at specific localized regions where the domain wall stopping structure is positioned on the magnetic track. Rather than requiring uniform magnetic field control across the entire sensor, the field is applied locally at the stopping structure location to achieve precise domain wall annihilation and configuration control
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 initialization of the sensor into a known state suitable for the current position of the mechanical system, allowing for accurate turn counting and fault detection without mechanical system repositioning.
Implementation Method 1
A strong magnetic field is first applied to fill the MT sensor with domain walls
Implementation Method 2
generating a first magnetic field in proximity to the multi-turn sensor such that domain walls are generated at a plurality of locations along the length of magnetic track
Implementation Method 3
applying a current to at least one domain wall stopping structure arranged along at least one portion of the magnetic track, such that a further magnetic field is generated in the region of the at least one domain wall stopping structure
Implementation Method 4
applying a rotating magnet field in proximity to the multi-turn sensor, such that the domain walls are caused to propagate around the length of magnetic track
Implementation Method 5
the domain walls are caused to propagate around the length of magnetic track
Implementation Method 6
magnetic multi-turn sensors typically use magnetoresistive elements that are sensitive to an applied external magnetic field. The resistance of the magnetoresistive elements in multi-turn sensors can be changed by rotating a magnetic field within the vicinity of the sensor
Data Source
AI summary
The present disclosure provides magnetic sensor system that includes a magnetic sensing device comprising a magnetic multi-turn sensor, and a method of initializing the magnetic multi-turn sensor into a known state with a defined domain wall configuration. A strong magnetic field is first applied to fill the MT sensor with domain walls. A current is then applied to a domain wall stopping structure arranged over at least one portion of the MT sensor, and the working magnetic field (i.e., the magnetic field generated by a magnet mounted on the mechanical system) is rotated until the desired domain wall configuration is achieved. Once the desired domain wall configuration is achieved, the current applied to the domain wall stopping structure is stopped and the MT sensor is ready for use. The sensor can be initialized into a known state without needing to drive the mechanical system to a start or end position.