Single Magnet Haptic Engine Yaw Sensing

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Solution Overview

Problem

Conventional haptic engines face challenges in sensing yaw modes due to the reliance on arrays of sensing magnets with narrow aspect ratios, which are prone to reliability issues and increased material costs, and struggle to miniaturize while maintaining sensitivity.

Innovation Solution

A haptic engine design featuring a single sensing magnet carried by the moving mass, with Hall-effect sensors spaced apart to detect changes in the magnetic field, allowing for the detection of yaw and Z modes alongside X mode, and enabling active damping of unwanted modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an array of sensing magnets is used to sense yaw modes, then yaw sensing capability is improved, but the aspect ratio of sensing magnets becomes very narrow which compromises reliability

Engineering Contradiction:

Improveyaw sensing capabilityVSAvoidsensing magnet reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts the sensing function from multiple sensing magnets and concentrates it into a single sensing magnet. This single magnet is positioned to work with multiple Hall-effect sensors arranged in different orientations, thereby maintaining yaw sensing capability while eliminating the reliability issues associated with narrow aspect ratio magnets

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The single sensing magnet is designed to serve multiple functions by interacting with multiple Hall-effect sensors positioned at different locations and orientations. This configuration allows the same magnet to contribute to sensing X, Y, and Z modes as well as yaw, eliminating the need for specialized narrow magnets

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If an array of sensing magnets is used to sense yaw modes, then yaw sensing capability is improved, but material costs increase

Engineering Contradiction:

Improveyaw sensing capabilityVSAvoidmaterial cost

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges the sensing function previously distributed across multiple sensing magnets into a single magnet. This consolidation reduces the total quantity of magnetic material required while maintaining the ability to sense yaw modes through the combined output of multiple Hall-effect sensors positioned strategically around the single magnet

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single sensing magnet is designed to be multi-functional, contributing to the sensing of multiple motion modes (X, Y, Z translations and yaw rotation) simultaneously. This eliminates the need for additional specialized magnets, thereby reducing material costs while maintaining comprehensive sensing capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If sensing magnets are spaced apart from static magnets to avoid interaction, then measurement precision is improved, but the size of the haptic engine increases

Engineering Contradiction:

Improvedisplacement sensing precisionVSAvoidhaptic engine size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent applies local quality by positioning the single sensing magnet and multiple Hall-effect sensors in specific locations where the magnetic field gradient is optimal for sensing. This allows precise displacement measurement without requiring large separations from static magnets, as the sensors are placed in regions of maximum field sensitivity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes spatial arrangement in multiple dimensions by positioning Hall-effect sensors at different locations and orientations around the single sensing magnet. This three-dimensional configuration allows the system to achieve accurate sensing with compact spacing, as the sensors capture magnetic field information from multiple spatial perspectives

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

This design reduces the size and material costs of the haptic engine, improves signal integrity, and enables effective sensing of all relevant modes, including yaw, while maintaining sensitivity and allowing for active damping of unwanted vibrations.

Implementation Method 1

Two or more Hall-effect sensors, which are spaced apart (i) from each other along a direction parallel to the driving direction and (ii) from the single sensing magnet along a direction orthogonal to the driving direction, are disposed adjacent to an ASIC that receives the sensors' output

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS10837844B2Haptic engine having a single sensing magnet and multiple hall-effect sensors

Publication Date: 2020.11.17 APPLE INC

AI summary

A haptic engine for measuring displacement of the haptic engine's mass uses a single sensing magnet that is carried by the mass along a driving direction. The haptic engine further uses two or more Hall-effect sensors, which are spaced apart (i) from each other along a direction parallel to the driving direction and (ii) from the single sensing magnet along a direction orthogonal to the driving direction, and are disposed adjacent to an ASIC that receives the sensors' output.