Vibration Type Actuator Resonance Frequency Control

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Solution Overview

Problem

Conventional vibration type actuators experience performance degradation due to variations in resonance frequencies of vibrating elements, leading to inefficiencies in motor performance.

Innovation Solution

The vibration type actuator is designed with multiple vibrating elements that operate in both first and second vibration modes, where the minimum resonance frequency of the second mode is greater than or equal to the maximum of the first mode, and the ratio of the difference between the maximum and minimum resonance frequencies in the second mode is controlled to minimize performance degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a plurality of vibrating elements with different resonance frequencies are used, then the actuator can be driven by a common alternating signal, but the performance of the actuator is degraded due to resonance frequency variations

Engineering Contradiction:

Improvecommon drive signal compatibilityVSAvoidactuator performance stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by carefully selecting and controlling the resonance frequency parameters of multiple vibrating elements. Specifically, it ensures that the minimum resonance frequency in the second vibration mode is greater than or equal to the maximum resonance frequency in the first vibration mode, and controls the ratio of frequency difference to minimum frequency to be within a predetermined value. This parameter optimization allows multiple vibrating elements to operate effectively with a common drive signal while maintaining stable actuator performance.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the resonance frequencies of vibrating elements are varied, then different vibration modes can be achieved, but the performance deterioration occurs due to frequency mismatch

Engineering Contradiction:

Improvevibration mode capabilityVSAvoidmotor performance consistency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent utilizes parameter changes to achieve multiple vibration modes while maintaining performance consistency. By optimizing the resonance frequency parameters within specific ranges and relationships, the system can exploit different vibration modes (first and second modes) for versatile operation while ensuring that frequency variations do not lead to performance deterioration.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies dynamics by enabling the vibrating elements to operate in multiple vibration modes with different frequency characteristics. The system dynamically switches between or combines first and second vibration modes, where each mode has distinct resonance frequency properties, allowing adaptable operation while maintaining overall performance through controlled frequency relationships.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If one contact element is driven by a plurality of vibrating elements using one booster circuit, then the device complexity is reduced, but the actuator performance might be degraded depending on the combination of vibrating elements

Engineering Contradiction:

Improvedrive circuit configurationVSAvoidactuator performance consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent resolves this contradiction by optimizing the resonance frequency parameters of the vibrating elements to work harmoniously with a common booster circuit. By ensuring that the minimum resonance frequency in the second mode is greater than or equal to the maximum resonance frequency in the first mode, and controlling the frequency ratio within predetermined limits, the system achieves consistent performance across different vibrating element combinations while using a single drive circuit.

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

This configuration reduces performance deterioration caused by resonance frequency variations, ensuring stable and efficient motor operation by optimizing the resonance frequencies and their differences in the second vibration mode.

Implementation Method 1

a piezoelectric element 3 having a shape of a rectangular thin plate, and an elastic element 2 that is integrally bonded to the piezoelectric element 3

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a resonance frequency varies due to variations in dimensions of an elastic element and a piezoelectric element

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS11336210B2Vibration type actuator and manufacturing method of vibration type actuator

Publication Date: 2022.05.17 CANON KK

AI summary

A vibration type actuator including vibrating elements and a contact element that is brought into contact with each other in a first direction. The vibration of the vibrating elements includes vibration in a first vibration mode in the first direction and vibration in a second vibration mode in a second direction intersecting the first direction. In the vibrating elements, a minimum value of a resonance frequency in the second vibration mode is greater than or equal to a maximum value of a resonance frequency in the first vibration mode, and a ratio of a difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second mode is less than or equal to a predetermined value.