Piezo Actuator Assembly Feedback for Synchronized Motion Control

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Solution Overview

Problem

Existing actuator assemblies using multiple piezo or electrostrictive actuators face challenges in achieving precise control, as manufacturing tolerances can lead to differences in expansion and contraction, resulting in non-zero resultant forces that cause vibrations and stress in the load.

Innovation Solution

An actuator assembly comprising a first and second piezo or electrostrictive actuator, along with a correction unit that determines an output voltage difference between the actuators and adjusts the power signals to ensure synchronized expansion and contraction, thereby reducing vibrations and stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple piezo or electrostrictive actuators are used to achieve desired positioning, then positioning capability is improved, but manufacturing tolerances cause differences in expansion and contraction leading to non-zero resultant forces that cause vibrations and stress in the load

Engineering Contradiction:

Improvepositioning precisionVSAvoidvibrations and stress in load

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The correction unit measures the actual voltages at the output terminals of both actuators, calculates the voltage difference, and generates correction signals to adjust the power signals. This closed-loop feedback mechanism compensates for manufacturing tolerances and ensures synchronized operation, eliminating vibrations and stress in the load while maintaining high positioning precision

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the power signal parameters (voltage or current) applied to each actuator based on real-time voltage measurements. By changing the electrical parameters of the power signals individually for each actuator, the system compensates for differences in actuator characteristics and achieves synchronized expansion and contraction without harmful resultant forces

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 proposed solution improves the control of piezo or electrostrictive actuators, reducing vibrations and deformations of the load by ensuring synchronized movement, thus enhancing the precision and accuracy of load positioning.

Implementation Method 1

a first piezo or electrostrictive actuator configured to expand or contract in a first direction when a voltage difference is present between the input terminal and the output terminal

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a second piezo or electrostrictive actuator configured to expand or contract in a second direction when a voltage difference is present between the input terminal and the output terminal

Methodology Applied

Scientific EffectElectrostriction: Electrostriction

Data Source

PatentUS12210294B2Actuator assemblies comprising piezo actuators or electrostrictive actuators

Publication Date: 2025.01.28 ASML NETHERLANDS BV

AI summary

An actuator assembly including a first piezo actuator and a second piezo actuator. The piezo actuator has a correction unit configured to determine an output voltage difference representing a difference between a voltage at the output terminal of the first piezo actuator and a voltage at the output terminal of the second piezo actuator, and a first power correction for correcting the first power signal and/or a second power correction for correcting the second power signal, based on the output voltage difference.