Linear Resonant Actuator Pulse Width Control for Low-Frequency Noise Reduction

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Solution Overview

Problem

Conventional tactile sensation providing apparatus using pulse waves generate noise when the frequency of vibration is low.

Innovation Solution

A tactile sensation providing apparatus that includes a linear resonant actuator and circuitry to adjust the pulse width of the pulse wave to be smaller than half of the reciprocal of the frequency when the frequency is below the resonance frequency of the actuator, reducing noise generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a pulse wave is used as a driving signal for the linear resonant actuator, then the apparatus can be downsized, but noise is generated in tactile sensation when the vibration frequency is low

Engineering Contradiction:

Improveapparatus sizeVSAvoidnoise in tactile sensation

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The pulse width of the driving signal is dynamically adjusted based on the vibration frequency. When the frequency is low, the pulse width is set to be smaller than half of the reciprocal of the frequency, preventing noise generation while maintaining the downsized apparatus structure.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The pulse width parameter of the driving signal is changed according to the vibration frequency. By setting the pulse width to be smaller than half of the reciprocal of the frequency at low frequencies, the noise problem is solved without changing the apparatus structure.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the pulse width is increased to improve tactile sensation at low frequencies, then the tactile sensation may be enhanced, but noise is generated

Engineering Contradiction:

Improvetactile sensation qualityVSAvoidnoise

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The pulse width is dynamically set based on the frequency condition. At low frequencies, the pulse width is specifically controlled to be smaller than half of the reciprocal of the frequency, achieving a balance between tactile sensation quality and noise reduction.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The driving signal maintains continuous effective action by adjusting the pulse width appropriately for each frequency condition, ensuring tactile sensation quality without generating noise through excessive pulse width.

Inventive Principle:

Principle #20Continuity of useful action

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

Effectively reduces noise in tactile sensations even at low vibration frequencies by ensuring the pulse wave's pulse width is optimized based on the actuator's resonance frequency.

Implementation Method 1

a linear resonant actuator (LRA)... a resonance frequency of the linear resonant actuator

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS11776367B2Tactile sensation providing apparatus, tactile sensation providing system, control method, and non-transitory recording medium

Publication Date: 2023.10.03 ALPS ALPINE CO LTD

AI summary

A tactile sensation providing apparatus includes a linear resonant actuator; and circuitry configured to provide a pulse wave to the linear resonant actuator as a driving signal. The circuitry is further configured to, when a frequency of the pulse wave is smaller than a resonance frequency of the linear resonant actuator, set a pulse width of the pulse wave at a value smaller than a half of a reciprocal of the frequency of the pulse wave.