Multi-Actuator Vibration Control for Beat-Free Wide Speed Range

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Solution Overview

Problem

Conventional vibration actuator systems face limitations in driving speed ranges due to frequency differences between multiple actuators, leading to the production of beat notes and restricted operational flexibility.

Innovation Solution

A vibration actuator control device that adjusts the phase difference and driving frequency of multiple actuators to synchronize their operations, allowing for a wide range of driving speeds by controlling the elliptical motion and frequency of piezoelectric elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the driving frequency difference between multiple vibration actuators is reduced to prevent beat notes, then the beat note is suppressed, but the range of driving speeds is reduced

Engineering Contradiction:
Improvebeat noteVSAvoiddriving speed range
Core Design Contradiction:
Object-affected harmful factorsVSSpeed

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the driving frequency of each vibration actuator based on its individual resonance characteristics. Instead of using a fixed frequency difference threshold, the control device modifies the driving frequency parameters in real-time to match each actuator's optimal operating point, thereby preventing beat notes while preserving the full driving speed range.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control by continuously monitoring the operating state of each vibration actuator and adjusting the driving frequency accordingly. The control device receives feedback on the actual performance of each actuator and modifies the driving parameters to maintain synchronization and eliminate beat notes, while adapting to preserve the maximum driving speed range.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the driving frequency of multiple vibration actuators is synchronized to a fixed value, then the beat note is eliminated, but the adaptability to different driving conditions is reduced

Engineering Contradiction:
Improvebeat noteVSAvoiddriving speed adaptability
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by transitioning from a static, fixed-frequency synchronization approach to a dynamic frequency adjustment mechanism. The control device continuously adapts the driving frequency of each actuator based on real-time operating conditions, allowing the system to maintain synchronization and eliminate beat notes while simultaneously adapting to various driving speed requirements and operational scenarios.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes parameter changes by modifying the driving frequency parameters dynamically rather than maintaining a fixed synchronized frequency. Each vibration actuator's driving frequency is adjusted according to its individual characteristics and current operating conditions, enabling the system to eliminate beat notes while maintaining versatility across different driving scenarios.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the driving frequency difference between vibration actuators is kept small, then the beat note is reduced, but the range of elliptical motion control is limited

Engineering Contradiction:
Improvebeat noteVSAvoidelliptical motion control range
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent implements feedback control to monitor and adjust the driving frequency of each vibration actuator based on its individual resonance characteristics and operating state. This feedback mechanism allows the system to eliminate beat notes by synchronizing actuators while simultaneously maintaining the full range of elliptical motion control, as each actuator can be independently optimized for its operational requirements.

Inventive Principle:
Principle #23Feedback

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

Enables synchronized operation of multiple actuators without beat notes, achieving a broad range of driving speeds and flexible control over the actuator's motion, suitable for applications like camera lenses.

Implementation Method 1

a contact body in contact with a vibrating body moves relative to the vibrating body by a vibration generated in the vibrating body

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3975413B1Vibration actuator control apparatus, vibration driving apparatus including the same, and electronic device
Publication Date: 2025.09.03 CANON KK
  • EP3975413B1 patent drawingFigure 1
  • EP3975413B1 patent drawingFigure 2A~2B
  • EP3975413B1 patent drawingFigure 3

AI summary

A vibration actuator control device includes a control unit and a driving unit. The control unit outputs a first control signal for controlling driving of a first vibration actuator including a first vibrating body and a first contact body, and outputs a second control signal for controlling driving of a second vibration actuator and including a second vibrating body. The driving unit (i) outputs a first alternating-current voltage in a first plurality of phases set based on the first control signal, and (ii) outputs a second alternating-current voltage in a second plurality of phases set based on the second control signal. The control unit individually sets a phase difference of the first alternating-current voltage based on the first control signal and sets a phase difference of the second alternating-current voltage based on the second control signal, and commonly sets a first alternating-current voltage frequency and a second alternating-current voltage frequency.