Piezoelectric Actuator Driving via Amplitude Modulation

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Solution Overview

Problem

High-frequency vibration of piezoelectric actuators in tactile sense devices leads to increased power consumption, heat generation, and noise, limiting the effective presentation of new tactile sensations.

Innovation Solution

A driving apparatus that uses a low-frequency signal wave (10 Hz to 250 Hz) as a modulating wave to modulate the amplitude of a high-frequency sine wave (20 kHz to 40 kHz) for the piezoelectric actuator, reducing power consumption and noise while generating new tactile sensations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a piezoelectric actuator operates at high frequency (20-40 kHz) to generate high-frequency vibrations for new tactile sensations, then new tactile senses can be presented to users, but power consumption increases

Engineering Contradiction:

Improvetactile sense expressionVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by using amplitude modulation where a low-frequency signal (10-250 Hz) modulates the amplitude of a high-frequency carrier wave (20-40 kHz). This creates a periodic envelope that allows the piezoelectric actuator to operate at high frequency while the perceived vibration follows the lower frequency modulation pattern, reducing overall power consumption while maintaining tactile sensation capability.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent changes the parameter of vibration frequency from continuous high-frequency operation to modulated frequency operation. By varying the amplitude parameter using a low-frequency modulating signal, the system achieves diverse tactile sensations without requiring continuous high-power high-frequency operation, thus resolving the contradiction between tactile versatility and power consumption.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

Engineering Contradiction:

Improvetactile sense expressionVSAvoidheat generation

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The amplitude modulation technique creates periodic on-off cycles where the high-frequency carrier is activated only during the positive amplitude cycles of the modulating signal. This periodic action reduces the duty cycle of high-frequency operation, thereby reducing heat generation while still presenting new tactile sensations during the active periods.

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

Engineering Contradiction:

Improvetactile sense expressionVSAvoidnoise generation

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potentially harmful high-frequency noise into a beneficial tactile sensation by using amplitude modulation. The high-frequency carrier (20-40 kHz) that would normally generate audible noise is modulated such that its energy is concentrated in the lower frequency range (10-250 Hz) where it produces desirable tactile feedback rather than unwanted noise, effectively converting a harmful factor into a beneficial one.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 configuration effectively presents new tactile sensations by reducing power consumption and heat generation, while minimizing noise, and enhances the sensitivity of tactile feedback through controlled amplitude modulation.

Implementation Method 1

piezoelectric actuators are also used for a force feedback function

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11633761B2Driving apparatus, vibration generating apparatus, electronic apparatus, and driving method

Publication Date: 2023.04.25 TAIYO YUDEN KK

AI summary

Provided is a driving apparatus that sets a signal wave in a low-frequency region having a frequency of 10 Hz or more and 250 Hz or less as a modulating wave and outputs to a piezoelectric actuator a driving signal having a waveform obtained by modulating an amplitude of a sine wave in a high-frequency region having a frequency of 20 kHz or more and 40 kHz or less with the modulating wave.