Piezoelectric Driving Device with Independent Axis Force Control

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Solution Overview

Problem

Existing piezoelectric driving devices face challenges in achieving both stable driving and power saving due to the need for balanced driving and holding forces, often resulting in excessive or insufficient forces when using the same piezoelectric actuators for different axes.

Innovation Solution

A piezoelectric driving device configuration with separate first and second moving sections, each driven by a distinct piezoelectric actuator, allowing independent setting of holding and driving forces, and utilizing stacked piezoelectric actuators to optimize force distribution and reduce size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the same piezoelectric actuators are used for both the first piezoelectric actuator (moving first moving body in X-axis) and the second piezoelectric actuator (moving second moving body in Y-axis), then device complexity is reduced, but either the driving force and holding force become excessive (wasting power) or insufficient (unstable driving)

Engineering Contradiction:

Improvecomplexity of piezoelectric actuator configurationVSAvoiddriving electric power consumption

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent divides the piezoelectric actuator system into separate first and second piezoelectric actuators, each independently configured according to the specific driving and holding force requirements of their respective moving bodies. This segmentation allows optimal force matching for each axis without compromising the other, resolving the contradiction between device simplicity and energy efficiency.

Inventive Principle:

Principle #1Segmentation

2Reliability

If piezoelectric actuators are selected based on the larger driving force and holding force requirements (for moving and holding the first moving body), then stable driving of the stage is achieved, but driving electric power is wasted due to excessive force for the second piezoelectric actuator

Engineering Contradiction:

Improvestability of stage drivingVSAvoidwasted driving electric power

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by configuring each piezoelectric actuator with properties specifically suited to its local requirements. The first piezoelectric actuator is configured with higher driving and holding force capabilities to ensure stable movement of the first moving body, while the second piezoelectric actuator is configured with appropriate force levels for the second moving body, preventing energy waste without compromising overall system stability.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If piezoelectric actuators are selected based on the smaller driving force and holding force requirements (for moving and holding the second moving body), then power saving is achieved, but the driving force and holding force become insufficient for stable driving of the stage

Engineering Contradiction:

Improvedriving electric power consumptionVSAvoidstability of stage driving

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent implements local quality by tailoring the force characteristics of each piezoelectric actuator to its specific operational context. The first piezoelectric actuator is designed with sufficient driving and holding force to ensure stable stage operation, while the second piezoelectric actuator is optimized with appropriate force levels for its lighter load, achieving power savings without compromising overall system reliability.

Inventive Principle:

Principle #3Local quality

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 enables stable and efficient operation by preventing excessive or insufficient forces, achieving both stable driving and power saving while allowing for convenient adjustment of forces and reducing device size and weight.

Implementation Method 1

a first piezoelectric actuator and configured to drive the first piezoelectric actuator to move the first moving section

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

stop the first piezoelectric actuator to hold the first moving section on the supporting section

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11043909B2Piezoelectric driving device, electronic-component conveying apparatus, and robot

Publication Date: 2021.06.22 SEIKO EPSON CORP

AI summary

A piezoelectric driving device includes a supporting section, a first moving section movable in a first direction relative to the supporting section, a second moving section movable in a second direction relative to the first moving section, a first driving section configured to drive a first piezoelectric actuator to move the first moving section relative to the supporting section and stop the first piezoelectric actuator to hold the first moving section on the supporting section, and a second driving section configured to drive a second piezoelectric actuator to move the second moving section relative to the first moving section and stop the second piezoelectric actuator to hold the second moving section on the first moving section. A first holding force for holding the first moving section on the supporting section and a second holding force for holding the second moving section on the first moving section are different from each other.