In vivo sound source using dielectric elastomer actuator to mount endoscope

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18858
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Mechanical dynamics, Robotics, and related fields
• Research Institution: Shibaura Institute of Technology
• Principal Investigator: Hosoya Naoki 芝浦工業大学, 工学部, 教授 (40344957)
• Co-Investigator(Kenkyū-buntansha): 前田 真吾 芝浦工業大学, 工学部, 准教授 (40424808)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: 誘電エラストマーアクチュエータ / スピーカ / 3次元構造体 / 高速応答性 / 音響放射特性 / 点音源 / 指向性 / 振動制御

Outline of Final Research Achievements

A balloon dielectric elastomer actuator (DEA) speaker is constructed by forming a disk-shaped DEA film into a sphere using air, increasing its surface area by 3033%. Sound is generated via expansion and contraction. Shaping the DEA film into a sphere decreases the film thickness and applies a significant amount of pre-strain to the film, allowing low-voltage (800 V) operations and rapid responses at high frequencies of up to 16 kHz. This is the first time to achieve ultra-fast response of acrylic DEA. The acoustic radiation pattern of the speaker extends over a 270 degrees range. Compared to polyhedron loudspeakers, which are currently used as omnidirectional sound sources in general acoustic tests, a balloon DEA speaker is compact and lightweight. Furthermore, we demonstrate a concave shape DEA speaker, yielding an acoustic radiation pattern controllable speaker from an omnidirectional to directional.

Free Research Field

機械力学

Academic Significance and Societal Importance of the Research Achievements

従来，複数のダイナミックスピーカを組み合わせ，正多面体スピーカとすることで点音源を実現したり，線上に並べることで線音源を実現したりしてきた．所望の音響放射特性を実現するためには，必ず複数のスピーカを組み合わせる必要があった．本研究成果により，1つのスピーカで音響放射特性を無指向性から指向性まで制御できるようになった．DEAスピーカは軽量かつ小型であるため，様々なデバイスへの搭載を可能にする．このDEAスピーカを内視鏡に実装し，腹部超音波エコー検査のように，生体組織を内部から点または面で加振できれば，生体組織の可視化における時空間分解能が向上し，病変の早期発見に大きく寄与することが期待される．