Soft Tissue Mechanics in Human Dexterity
via Internal Sensing

Project Description

We will investigate how mechanically human soft tissues such as skin and cartilage contribute to human motion dexterity.

Human can grasp various objects and manipulate various tools dexterously involuntarily. Scientific researches to reveal such human dexterity have been conducted so far. In physiology, grasp configuration according to object shapes and activity of brain-nerve system during human hand motion has been studied. Signal transmission along nerve lines and brain activities during human manipulating objects have been investigated and plenty of observation have been reported. But, mechanics of human dexterous manipulation including objects has not been clarified yet. In robotics, haptic perception through soft tissues has been analyzed mechanically and object grasping via soft fingertips has been studied. It turns out that soft tissues work as mechanical filters during haptic perception and shaping of potential energy contributes to secure object grasping. Unfortunately, it is not clear if such theories can be applied to actual human grasping and manipulation. In this research project, we will measure inner deformation of soft tissues such as human skin and cartilage during grasping and manipulation via MR (magnetic resonance) technology and investigate the mechanics of soft tissues in human dexterous manipulation.

This project consists of the following research topics:

  1. Measurement of inner deformation of human hands/fingers via MR device
  2. Computation of inner deformation fields from MR volumetric images
  3. Mechanical modeling and identification of soft tissues
  4. Mechanical modeling of three-dimensional soft-fingered manipulation
  5. Dynamic simulation of human grasping and manipulation
First, we will clarify condition for MR imaging that enables the measurement of human soft tissues. Especially, we will establish a method to measure inner deformation of human hands/fingers during grasping and manipulation. Second, We will establish a technique to compute the inner deformation field from multiple MR volumetric images. We will investigate robust computation of deformation fields. Third, we will investigate the modeling of soft tissues and the identification of model parameters involved. We will extend our viscoelastic/viscoplastic/rheological deformation models so that the soft tissue deformation can be described approproately. In addition to soft tissue modeling, we will formulate boundary conditions due to contact among fingers and objects. Fourth, we will formulate object grasping and manipulation in 3D space performed by soft fingertips. We will realize dynamic simulation of object grasping and manipulation in 3D space considering soft tissue deformation. Through dynamic simulation, we will investigate the mechanics of soft tissues during object grasping and manipulation to show that potential energy contributes to human grasping and manipulation.

proposal (in Japanese)


Hirai, Shinichi Professor, Dept. Robotics, Ritsumeikan Univ.
Tanaka, Hiromi Professor, Dept. Computer Science, Ritsumeikan Univ.
Inubushi, Toshiro Professor, Biomedical MR Center, Shiga Univ. of Medical Science
Morikawa, Shigehiro Associate Professor, Biomedical MR Center, Shiga Univ. of Medical Science
Inoue, Takahiro Assistant Professor, Dept. System Eng. of Sports, Okayama Prefectural Univ.
Kita, Yasuyo Interactive Vision Group, Information Tech. Research Inst., AIST
Tokumoto, Shinichi Researcher, Industrial Tech. Center of Wakayama Prefecture


report (in Japanese)


Book Chapters
Conference Papers


MR slices of artificial soft fingertip during object rotation

Simulation of grasping and rotation by soft fingertips (movie)

Simulation of soft-fingered grasping and manipulation Strain via contact between soft fingertip and object

Grasping by three 1-DOF fingers with soft fingertips

Related Sites

Virtual Rheology Project