Self-Sensing Piezoelectric Coil for Displacement Feedback Control

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Solution Overview

Problem

There is a need for a technology capable of performing displacement sensing in piezoelectric coils, as existing technologies do not effectively address this requirement.

Innovation Solution

A piezoelectric coil with a sensor is developed, comprising a coil-shaped core and helically wound first and second piezoelectric members that are expandable and contractable, where the second piezoelectric member functions as a displacement sensor to detect the expansion and contraction of the coil, allowing for self-sensing capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate displacement sensor is added to the piezoelectric coil, then displacement sensing capability is improved, but device complexity and size increase

Engineering Contradiction:

Improvedisplacement sensing capabilityVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the actuator function and sensor function into a single integrated piezoelectric coil structure. The second piezoelectric member serves dual purposes: it acts as both an actuator (when voltage is applied) and as a sensor (when it generates voltage through deformation). This merging eliminates the need for separate displacement sensors and reduces overall device complexity while maintaining displacement sensing capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The second piezoelectric member is designed to perform multiple functions: it can be driven as an actuator to produce displacement, and simultaneously serve as a sensor to detect displacement through the piezoelectric effect. This multi-functionality allows the same component to replace what would traditionally require separate actuator and sensor elements, thereby reducing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If a separate displacement sensor is added to the piezoelectric coil, then displacement sensing capability is improved, but the size of the device increases

Engineering Contradiction:

Improvedisplacement sensing capabilityVSAvoiddevice size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If feedback control is implemented using displacement sensing, then operational reliability is improved, but device complexity increases

Engineering Contradiction:

Improveoperational reliabilityVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback control by using the voltage generated by the second piezoelectric member (which detects displacement) to feed back to the driving unit. This allows the system to monitor its own displacement in real-time and adjust the driving voltage accordingly, improving operational reliability by preventing excessive displacement and ensuring precise control.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The piezoelectric coil is designed to be self-sensing, where the second piezoelectric member automatically provides displacement information without requiring external sensors. The system uses its own structural deformation to generate feedback signals, enabling self-monitoring and self-regulation that simplifies the overall control system while improving reliability.

Inventive Principle:

Principle #25Self-service

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 solution enables accurate displacement sensing and feedback control of the piezoelectric coil, improving its performance and allowing for miniaturization while eliminating the need for separate displacement sensors, thereby enhancing its operational range and preventing damage from excessive displacement.

Implementation Method 1

when an electric field is applied to the piezoelectric element, the piezoelectric element deforms in the longitudinal direction

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the piezoelectric member that is helical relative to the core and that surrounds the first piezoelectric member... the second piezoelectric member functions as a displacement sensor

Methodology Applied

Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentUS20240288284A1Piezoelectric coil with a sensor and electronic apparatus

Publication Date: 2024.08.29 SONY GROUP CORP

AI summary

[Object] To provide a technology relating to a piezoelectric coil or the like capable of performing displacement sensing.[Solving Means] A piezoelectric coil with a sensor according to the present technology includes: a piezoelectric coil; and a sensor. The piezoelectric coil includes a coil-shaped core and one or more first piezoelectric members that are helical relative to the core, and is expandable and contractable in an expanding/contracting direction. The sensor detects a displacement due to expansion and contraction of the piezoelectric coil.