Piezoelectric Drive Phase Difference Control

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Solution Overview

Problem

Existing piezoelectric drive devices face challenges in accurately detecting the vibration state due to variations in the duty of the drive pulse signal, which affects the phase difference between drive and detection signals, leading to inaccurate vibration control.

Innovation Solution

A control device and method for a piezoelectric drive device that generates binary drive and detection pulse signals, with a phase difference acquisition unit that measures the phase difference based on the rising and falling edges of both signals, independent of the drive pulse signal's duty, ensuring accurate vibration state detection and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the duty of the drive pulse signal is changed to control vibration amplitude, then the vibration amplitude can be adjusted, but the phase difference between drive and detection signals shifts leading to inaccurate vibration state detection

Engineering Contradiction:

Improvevibration amplitude controlVSAvoidvibration state detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces a phase difference acquisition unit that uses the rising and falling edges of both drive and detection pulse signals as intermediary reference points. By measuring phase difference based on these edge transitions rather than duty cycle, the system can control vibration amplitude while maintaining accurate phase difference measurement independent of duty changes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the measurement parameter from duty cycle-based phase difference to edge-transition-based phase difference. By acquiring phase difference based on rising and falling edges of binary pulse signals rather than duty ratio, the measurement becomes independent of duty changes, allowing amplitude control without compromising detection accuracy.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If a binary drive pulse signal is generated for control, then the control simplicity is improved, but the phase difference measurement accuracy may be affected by duty variations

Engineering Contradiction:

Improvecontrol simplicityVSAvoidphase difference measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent uses the rising and falling edges of binary pulse signals as intermediary reference points for phase difference measurement. This approach maintains the simplicity of binary control signals while achieving accurate phase difference measurement by focusing on edge transitions that occur regardless of duty cycle variations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional analog control methods with digital binary pulse control. By using edge detection of binary signals instead of analog duty cycle measurement, the system achieves both control simplicity and measurement accuracy through digital signal processing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 high-accuracy detection and control of the vibration state regardless of the drive pulse signal's duty, allowing for precise control of the piezoelectric drive device.

Implementation Method 1

a vibration body 11 that includes a piezoelectric element for drive and a piezoelectric element for detection, vibrates according to drive of the piezoelectric element for drive

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

outputs a detection signal according to the vibration from the piezoelectric element for detection

Methodology Applied

Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentUS11411512B2Control device and method for controlling a piezoelectric drive device using phase difference

Publication Date: 2022.08.09 SEIKO EPSON CORP

AI summary

A control device of a piezoelectric drive device includes a drive pulse signal generation unit that generates a binary drive pulse signal, a drive signal generation unit that generates a drive signal which is applied to the piezoelectric element for drive from the drive pulse signal, a detection pulse signal generation unit that generates a detection pulse signal by binarizing the detection signal which is output from the piezoelectric element for detection, and a phase difference acquisition unit that acquires a phase difference between the drive pulse signal and the detection pulse signal, based on a rising edge and a falling edge of the drive pulse signal and a rising edge and a falling edge of the detection pulse signal.