Motion Detection Device Gravity Axis Separation

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Solution Overview

Problem

Existing motion detection technologies face challenges in accurately distinguishing intended motion from unintended vibrations, leading to misdeterminations, especially when the device is in motion or subjected to shaking, and require complex processing to analyze acceleration features.

Innovation Solution

A motion detection device that uses a triaxial acceleration sensor to separate acceleration data into stationary and motion components through low-pass filtering, determines the gravity axis based on the largest stationary component, and identifies the motion axis by detecting the largest motion component, reducing misinterpretations from unintended vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If feature amount analysis is performed to recognize motion, then motion recognition accuracy is improved, but processing complexity increases

Engineering Contradiction:

Improvemotion recognition accuracyVSAvoidprocessing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments acceleration data into stationary components (obtained through low-pass filtering) and motion components (obtained by subtracting stationary components from total acceleration). This segmentation allows simple comparison of component magnitudes to determine motion axes without complex feature analysis, resolving the contradiction by achieving motion recognition through straightforward component separation rather than complicated feature extraction.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If gravity axis determination is performed in stationary state, then determination accuracy is improved, but applicability during motion decreases

Engineering Contradiction:

Improvegravity axis determination accuracyVSAvoidapplicability during motion

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent performs preliminary separation of acceleration components into stationary and motion components before determining the gravity axis. By extracting the stationary component through low-pass filtering first, the system can accurately determine the gravity axis even during device motion, as the stationary component represents gravity regardless of motion state. This preliminary separation enables gravity axis determination to work both in stationary and moving conditions.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If acceleration data is used during motion, then detection coverage is improved, but misdetermination from unintended motion increases

Engineering Contradiction:

Improvedetection coverageVSAvoidmisdetermination rate

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts and removes the stationary component (gravity) from the total acceleration data to isolate the motion component. By taking out the stationary component through low-pass filtering and subtraction, the system can analyze only the motion-related acceleration without interference from gravity or unintended vibrations, thereby maintaining high detection coverage while reducing misdeterminations during device motion.

Inventive Principle:

Principle #2Taking out (Extraction)

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 approach allows for accurate and simple detection of motion axes, reducing misinterpretations from unintended vibrations and improving the accuracy of motion recognition in electronic devices like mobile phones and game controllers.

Implementation Method 1

detects acceleration components of each axis of three-dimensional rectangular coordinate system of acceleration acting on the acceleration detection unit

Methodology Applied

Scientific EffectGravitation: Gravitation

Implementation Method 2

separates the outputted sets of acceleration component data into stationary components obtained by subjecting the outputted sets of acceleration component data to low-pass filter processing

Methodology Applied

Scientific EffectLow-pass filtering: Filter (electronic)

Data Source

PatentUS9417705B2Motion detection device, electronic device, motion detection method, and program storage medium

Publication Date: 2016.08.16 LAPIS SEMICON CO LTD

AI summary

A motion detection device includes: an acceleration detection unit, a separating unit, a gravity axis determination unit, and a motion detection unit. The acceleration detection unit detects acceleration components of each axis of a three-dimensional rectangular coordinate system of acceleration acting on the acceleration detection unit and outputs sets of acceleration component data. The separating unit separates the outputted sets of acceleration component data into stationary components and motion components. The gravity axis determination unit determines an axis whose separated stationary component is the largest to be a gravity axis. The motion detection unit detects, if an axis corresponding to a largest motion component showing a largest value of the separated motion components is an axis other than the determined gravity axis, a motion axis of the acceleration detection unit on the basis of the largest motion component.