Electromagnetic Actuator Control for Harmonic-Free Vibration Decay

Solution Overview

Problem

Existing vibration presenting apparatuses generate harmonics when adjusting the vibration attenuation period, leading to uncomfortable touch operation feelings and abnormal noise due to superimposed harmonics on the acceleration waveform.

Innovation Solution

A control device and vibration presenting apparatus that utilize an electromagnetic actuator with a specific configuration and control method to suppress harmonic generation by adjusting the vibration attenuation period, using a combination of main and sub-driving signals, including sine and square waves, to ensure smooth vibration transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a square wave pulse is applied to the coil of the electromagnetic actuator to adjust the vibration attenuation period, then the vibration attenuation period can be extended or shortened, but a harmonic is superimposed on the acceleration waveform due to current variation at pulse application and stopping times

Engineering Contradiction:

Improvevibration attenuation periodVSAvoidharmonic superimposition

Core Design Contradiction:

Duration of action of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent changes the waveform parameter from a square wave to a sine wave for the kick-in pulse and braking pulse. This parameter change eliminates the abrupt current transitions that cause harmonics, while still achieving the desired vibration attenuation period adjustment through the sinusoidal excitation of the electromagnetic actuator coil.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of using a square wave pulse that abruptly starts and stops current flow (causing harmonics), the patent inverts the approach by using a sine wave that smoothly varies current flow. This inversion of the waveform shape eliminates the harmful current transitions while maintaining the ability to control vibration attenuation.

Inventive Principle:

Principle #13The other way round (Inversion)

2Duration of action of moving object

If a square wave pulse is applied to the coil, then the vibration attenuation period can be adjusted, but abnormal noise occurs due to harmonic superimposition on the acceleration waveform

Engineering Contradiction:

Improvevibration attenuation periodVSAvoidabnormal noise

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the waveform parameter from a square wave to a sine wave for the kick-in pulse and braking pulse. This parameter change eliminates the abrupt current transitions that cause harmonics, while still achieving the desired vibration attenuation period adjustment through the sinusoidal excitation of the electromagnetic actuator coil.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of moving object

If a square wave pulse is applied to the coil, then the vibration attenuation period can be adjusted, but the touch operation feeling becomes uncomfortable due to harmonic superimposition

Engineering Contradiction:

Improvevibration attenuation periodVSAvoidtouch operation feeling comfort

Core Design Contradiction:

Duration of action of moving objectVSEase of operation

Solution Approach 1:

The patent changes the waveform parameter from a square wave to a sine wave for the kick-in pulse and braking pulse. This parameter change eliminates the abrupt current transitions that cause harmonics, while still achieving the desired vibration attenuation period adjustment through the sinusoidal excitation of the electromagnetic actuator coil.

Inventive Principle:

Principle #35Parameter changes

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

The solution effectively suppresses harmonic generation, providing a comfortable and noise-free touch operation feeling by ensuring smooth vibration attenuation periods.

Implementation Method 1

an electromagnetic actuator that drives an operation device, which is supported in an elastically vibratable manner by an elastic support part, in one direction of a vibration direction of the operation device to vibrate the operation device

Methodology Applied

Scientific EffectElectromagnetic actuation: Electromagnetic Induction

Implementation Method 2

an operation device, which is supported in an elastically vibratable manner by an elastic support part

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4343495B1Control device and vibration presenting apparatus

Publication Date: 2026.04.29 MITSUMI ELECTRIC CO LTD

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AI summary

Provided is a control device controlling an electromagnetic actuator that drives an operation device, supported in an elastically vibratable manner by an elastic support part, in one direction of a vibration direction of the operation device to vibrate the operation device. The control device includes a circuit that applies a main driving signal to a coil of the electromagnetic actuator to start vibration of the operation device in response to a touch operation on the operation device, then applies a sub-driving signal to the coil to adjust an attenuation period of the vibration. The sub-driving signal has a variable voltage varying with an offset voltage, as a center value, offset from a zero voltage, and a waveform that indicates a variation in the variable voltage is a sine function curve or a cosine function curve.