JAIST Repository
https://dspace.jaist.ac.jp/Title

湿潤接着性向上のための形態適応性ソフトコンタクトの機構

Author(s)NGUYEN, DANG DUYCitationIssue Date

2024-06

TypeThesis or Dissertation

Text version

ETDURLhttp://hdl.handle.net/10119/19333

RightsDescription

Supervisor: Ho Anh Van, 先端科学技術研究科, 博士

Japan Advanced Institute of Science and Technology

氏

名

NGUYEN DANG DUY

学

位の種類

博士（マテリアルサイエンス）

学

位記番号

博材第 582 号

学 位 授 与 年 月 日
論文題目論 文 審 査 委 員

令和 6 年 6 月 24 日
Mechanics of morphologically adaptive soft contact for wet adhesion
enhancement
HO Anh-Van

小矢野幹夫

北陸先端科学技術大学院大学准教授

同教授

村田英幸

同教授

池勇勳

同准教授

平井慎一

立命館大学教授

論文の内容の要旨
This thesis delves into the concept of animal adaptation to various environments through theability to morphologically adapt, often referred to as morphological design. It focuses on thesignificant role of tribological phenomena in different animal species, such as human fingers ingrasping, gecko toes in dry locomotion, and tree frog toes in wet gripping, and how these findings
can be applied to engineering. Wet adhesion, a crucial aspect in tribology, is explored, and its
potential application in robotics is investigated, particularly in the context of stable robot walking
that requires effective gait planning and control. The mechanical properties of the interaction
between robot feet and the ground surface are considered pivotal.
In this research, we propose a mechanics of morphology changeable soft pad for robotic foots
capable of adapting its morphology to the changing terrains that robots encounter. This adaptation
includes optimizing various tribological factors such as friction, adhesion, and particularly wetadhesion when the foot interacts with wet surfaces. The function of actively changing morphology toadapt to the environment plays an important role in embodied robots. The result proposed in thisthesis is promising to use for the application of embodied robots that perceive their surroundings tomanipulate objects or move their bodies, process information, and make decisions.
First, I establish a mathematical model based on energy equations to provide insights into theprinciples of morphological changes of the robot foot. I then present two approaches to model thevalue of wet adhesion in preventing slippage for the robot's foot. The first approach simplifies thefoot shape to streamline complex parameters for calculating wet adhesion forces. The second
approach introduces a more generalized model based on finite element methods to describe wetadhesion forces on a soft body interacting with various ground surfaces. This generalized model isvalidated and simulated using the Simulation Open Framework Architecture (SOFA framework).
Subsequently, we present experimental data that corroborates the accuracy of the mathematicalmodels proposed in this research. Finally, we test the application of the morphologically adaptablerobot foot in two scenarios using a separate legged robot and a complete hexapod robot in showcases.
These applications aim to showcase the effectiveness and potential practicality of a morphologically
adaptable robot foot.
In conclusion, this research advances our understanding of animal-inspired robotics, particularly
focusing on the significance of morphological adaptability and wet adhesion in robotic locomotion.
The proposed model and its practical application hold promise for the development of robots capableof efficiently traversing various terrains and adapting to different environments.
Keywords: Tribology, capillary, morphology computation, soft toe pad, animal locomotion, SOFA, finite element,
embodied robot
論文審査の結果の要旨
This thesis examines adaptation to various environments through morphological changes,
focusing on tribological phenomena in species like tree frog toes, and their engineering
applications. It explores wet adhesion in tribology and its relevance to robotics, particularly forstable walking requiring effective gait planning and control. The research proposes amorphologically adaptable soft pad for robotic feet to vary tribological factors, especially on wetsurfaces. This adaptation enhances embodied intelligence in maintaining stable actions, such aswalking in wet surfaces, even without complicated computation. In details:
1) This thesis establishes a mathematical model using energy equations to understandmorphological changes in robot feet. It presents two approaches to model wet adhesion toprevent slippage: a simplified foot shape model and a generalized model using finite element
methods. Experimental data supports the models' accuracy.
2) The morphologically adaptable robot foot is tested on a legged robot and a hexapod robot,demonstrating its effectiveness. The research enhances knowledge of animal-inspired
robotics, emphasizing morphological adaptability and wet adhesion, promising improved
robotic locomotion across various terrains.
Overall, the thesis succeeds in proposal of a scalable design of a morphologically changeable soft
pad, and thorough elaboration of its characteristics and operation. Also, obtained results
contribute to fulfilling knowledge of soft morphology in interaction with surrounding
environment. The research content in this research contributes to understanding wet adhesion
on macro scales, and paves a way to wide application in robotic application. The student could
prepare papers, thesis, and present the content in English without any problem. Therefore, thisthesis is sufficient to be rewarded as doctoral thesis.