Signal Processing Circuit for Magnetic Position Detection Offset Correction

Solution Overview

Problem

Existing magnetic position detection devices face challenges in quickly estimating center coordinates of a virtual sphere after changes in offsets of detection signals, due to complex computations required in existing methods, making it difficult to accurately correct position information in the presence of disturbances or changes in the environment.

Innovation Solution

A signal processing circuit that extracts a first and second point defining the longest line segment from a set of measurement points, determines the midpoint of this segment as the estimated center coordinates of the virtual sphere, and uses this information to detect and correct offsets in the detection signals, allowing for rapid adaptation to changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex computation methods are used to determine center coordinates of a virtual sphere, then measurement precision is improved, but processing time increases and productivity decreases

Engineering Contradiction:

Improveaccuracy of position detectionVSAvoidspeed of offset correction

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the essential information needed for offset correction by identifying the longest line segment among measurement points and using its midpoint as the center coordinates. This extraction approach avoids complex computations while retaining sufficient accuracy for practical purposes, thereby resolving the contradiction between measurement precision and processing speed.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using complex mathematical methods to precisely calculate the center of a virtual sphere formed by measurement points, the patent inverts the approach by using a simplified geometric construction: finding the longest line segment and taking its midpoint. This inverted approach achieves adequate precision much faster than traditional methods.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If complex computation methods are used to determine center coordinates of a virtual sphere, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improveaccuracy of position detectionVSAvoidcomplexity of signal processing circuit

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential information needed for offset correction by identifying the longest line segment among measurement points and using its midpoint as the center coordinates. This extraction approach avoids complex computations while retaining sufficient accuracy for practical purposes, thereby resolving the contradiction between measurement precision and processing speed.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs simple computational operations (finding maximum values, calculating midpoints) that can be implemented with basic circuit elements rather than complex processors. These simple computational 'objects' are sufficient for the task and can be implemented with minimal hardware complexity, resolving the contradiction between precision and device complexity.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If complex computation methods are used to determine center coordinates of a virtual sphere, then measurement precision is improved, but loss of time increases

Engineering Contradiction:

Improveaccuracy of position detectionVSAvoidtime for offset correction

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the essential information needed for offset correction by identifying the longest line segment among measurement points and using its midpoint as the center coordinates. This extraction approach avoids complex computations while retaining sufficient accuracy for practical purposes, thereby resolving the contradiction between measurement precision and processing speed.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary identification of the longest line segment characteristics (maximum and minimum coordinate values) to directly calculate the midpoint coordinates. This preliminary action approach avoids iterative or complex computational processes, achieving fast offset correction with adequate precision by preparing the essential data in advance.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11307052B2Signal processing circuit, position detection device, and magnetic sensor system

Publication Date: 2022.04.19 TDK CORP

AI summary

A magnetic sensor system includes a magnetic device and a signal processing circuit. The device generates first to third detection signals corresponding to components in three directions of a magnetic field generated by a magnetic field generator that is able to change its relative position with respect to the device. The circuit includes a longest segment extraction section and a midpoint coordinate computing section. With coordinates that represent a set of values of the first to third detection signals at a certain timing in an orthogonal coordinate system being taken as a measurement point, the longest segment extraction section extracts a first point and a second point that define a line segment having the greatest length among a plurality of measurement points at a plurality of timings. The midpoint coordinate computing section determines coordinates of a midpoint of the line segment defined by the first and second points.