Manipulability analysis of human thumb, index and middle fingers in cooperative 3D rotational movements of a small object

Abstract

SUMMARYThe combined motion of the human thumb, index and middle fingers while rotating a small object across the extended, intermediate and flexed planes with respect to the fingers was analyzed. Auto reflective markers were attached on the fingers to track their motion across three postures and planes via a 3D motion capture system. Central, right and left rotation postures were considered in each plane for investigation and the rotation experiments were performed with 30 healthy subjects. The obtained data were used to compute the finger joint angles. Based on the three criteria of (i) manipulability measure, (ii) major axis direction angle of the manipulability ellipsoid and (iii) ratio of the minor over major axis lengths, the collective behavior of the fingers was studied. It has been found after analysis that the thumb and middle finger were active, while the index finger operated passively when manipulating small objects in cooperative rotational motion across the three planes. Activeness refers to the independence of a digit in controlling the motion of an object whereas passiveness denotes its dependence on other digits. An active finger governs the motion of an object whereas a passive finger simply supports it. The results of this investigation are of great importance in planning treatment for rehabilitation and for designing controllers for robotic therapists, finger exoskeletons and prostheses.

An effort for resolving redundancy of a multi-finger robotic hand in straight-line motions

“…The value of R p (t) which is a kinematic parameter varies significantly in magnitude and allows mostly positive values but is rarely negative which is satisfying the Orlando et al's [44] results. It has been concluded that human beings and robotic finger vary R p (t) in both magnitude and order with finger configuration.…”

“…al. [44], where the redundancy resolution is carried out for cooperative motion of the thumb, index and middle fingers in order to translate a small object along with maximization of instantaneous manipulability. Similar outcomes are recorded based on the Yoshikawa [9] inverse kinematics model which demonstrates analytically that the finest finger posture corresponds to the maximum value of the manipulability measure.…”

On redundancy resolution of the human thumb, index and middle fingers in cooperative object translation

“…We expect that such models will help identify suitable algorithms for dynamic control in cases of coordinated translation tasks and free finger motion studied herein, and cooperative rotation manipulation explored elsewhere [Felix Orlando et al]. 56 This paper aims at providing a partial but crucial knowledgebase in finger motion that may assist in the design and development of, say, Electro-Encephalogram (EEG) or Electro-Myogram (EMG) based assistive devices in future.…”

“…Thus, use of a generic open chain to universally represent the thumb is difficult. In our previous effort [Felix Orlando et al], 56 we used a five-dof model for the thumb with universal joints, each at the MCP and CMC locations. The disadvantage therein with the orthogonal and intersecting axes was that the model may not capture the torque transmission into the thumb tip forces accurately.…”

Application of robotic manipulability indices to evaluate thumb performance during smartphone touch operations

“…Since human hand postures that hinder movement will affect performance, human manipulability might also be evaluated using robotic manipulability indices. Indeed, several researchers have reported the benefits of applying robotic manipulability indices to human movement (Chen et al 2010;Jacquier-Bret, Gorce, and Rezzoug 2012;Kanezashi et al 2008;Orlando et al 2013;Rezzoug et al 2012;Sasaki et al 2010;Seo, Matsui, and Doi 2008;Tanaka et al 2004;Yamazaki et al 2005;Yokogawa and Hara 2004). For upper limb movements, there was a correlation between the robotic manipulability index and results of human experiments (Seo, Matsui, and Doi 2008;Yamazaki et al 2005), and good upper limb posture for task execution could be predicted using this index (Kanezashi et al 2008;Yamazaki et al 2005).…”