Rotation Angle Sensor Disturbance Flux Reduction

Solution Overview

Problem

Conventional rotation angle sensors face challenges in detecting the rotation angle of a magnet with high precision due to disturbance magnetic flux from sources like leakage magnetic flux from motors or geomagnetic fields.

Innovation Solution

A rotation angle sensor system comprising a magnet with two poles, multiple magnetic detection elements positioned at specific angles relative to the magnet, and a calculation signal generator that outputs magnetic field calculation signals and an angle signal, effectively reducing the influence of disturbance magnetic flux by using a combination of magnetic field detection in different directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional magnetic detection elements are used to detect the rotation angle of a magnet, then the rotation angle can be detected, but disturbance magnetic flux (such as leakage magnetic flux from motors or geomagnetic fields) causes errors in the angle signal, reducing detection precision

Engineering Contradiction:

Improverotation angle detection precisionVSAvoiddisturbance magnetic flux influence

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The magnetic detection is segmented into multiple detection elements (first, second, third, and fourth magnetic detection elements) positioned at different angular positions around the magnet. Each element detects magnetic field components in different directions, and the signals are combined through calculation to eliminate disturbance components. This segmentation allows the system to distinguish between the magnet's rotational signal and disturbance magnetic flux.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention detects magnetic fields in multiple spatial dimensions by using detection elements oriented in different directions (first direction and second direction perpendicular to the rotational axis). By measuring magnetic field components in multiple dimensions and combining them through calculation, the system can identify and eliminate disturbance components that affect only certain dimensions, thereby improving rotation angle detection precision.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If multiple magnetic detection elements are added to reduce disturbance magnetic flux influence, then detection precision improves, but device complexity increases

Engineering Contradiction:

Improverotation angle detection precisionVSAvoidnumber of magnetic detection elements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The magnetic detection is segmented into multiple detection elements (first, second, third, and fourth magnetic detection elements) positioned at different angular positions around the magnet. Each element detects magnetic field components in different directions, and the signals are combined through calculation to eliminate disturbance components. This segmentation allows the system to distinguish between the magnet's rotational signal and disturbance magnetic flux.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention detects magnetic fields in multiple spatial dimensions by using detection elements oriented in different directions (first direction and second direction perpendicular to the rotational axis). By measuring magnetic field components in multiple dimensions and combining them through calculation, the system can identify and eliminate disturbance components that affect only certain dimensions, thereby improving rotation angle detection precision.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 precise detection of the rotation angle of a magnet even in environments with significant disturbance magnetic flux, enhancing the accuracy and reliability of the angle signal.

Implementation Method 1

a first magnetic detection element and a second magnetic detection element configured to detect a magnetic field in a first direction varying by a rotation of the magnet; a third magnetic detection element and a fourth magnetic detection element configured to detect the magnetic field in a second direction

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS11193794B2Rotation angle sensor, angle signal calculation method and non-transitory computer readable medium

Publication Date: 2021.12.07 ASAHI KASEI MICRODEVICES CORP

AI summary

A rotation angle sensor includes first and second magnetic detection elements disposed at positions where a first disposition angle relative to a magnet center is greater than 0 degrees and less than 90 degrees and configured to acquire magnetic field in a first direction varying by a rotation of a magnet; third and fourth magnetic detection elements configured to acquire the magnetic field in a second direction; a calculation signal generator configured to output a first magnetic field calculation signal, based on outputs of the first and second magnetic detection elements, and configured to output a second magnetic field calculation signal, based on outputs of the third and fourth magnetic detection elements; and an angle signal generator configured to generate and output an angle signal indicative of a rotation angle of the magnet, based on the first and second magnetic field calculation signal.