• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.4
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• pp.333-338
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• 2009

This paper presents a task-based analysis on the number of independent robotic fingers required for compliant manipulations. Based on the stiffness relation between operational space and fingertip space of a multi-fingered object manipulating system, we describe a technique for modulation of the fingertip stiffness without inter-finger coupling so as to achieve the desired stiffness specified in the operational space. Thus, we provides a guide line how many fingers are basically required for successful multi-fingered compliant tasks. Consequently, this paper enables us to assign effectively the number of fingers for various compliant manipulations by robot hands.

• Archives of Plastic Surgery
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• v.33 no.1
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• pp.124-126
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• 2006

Pachydermodactyly is a rare distinct form of fibromatosis characterized by acquired, asymptomatic dense fibrosis and fibroblastic proliferation around one or more proximal interphalangeal joints. Intralesional triamcinolone injection may be helpful in improving the clinical appearance. A 20-year-old unemployed female patient gave a four years history of progressive swelling of the fingers affecting predominantly the proximal interphalangeal joints of index fingers of left hand and index, middle fingers of right hand. There was no pain and tenderness. Physical examination, complete blood count, antinuclear antibody, rheumatoid factor were unremarkable and radiograph of both hands showed soft tissue swelling only without bony abnormality. We excised the redundant soft tissue from the both sides of proximal interphalangeal joint with longitudinal elliptical fashion. After operation, the fingers of the patient showed marked improvement cosmetically. There were no motor or sensory changes. Pachydermodactyly was first reported in 1996 in Korea. Histologic features include an increased dermal accumulation of collagen and occasionally an increased number of fibroblast. We report for one patient with pachydermodactyly treated with longitudinal elliptical excision and obtained an improvement of clinical appearance.

• Journal of the Ergonomics Society of Korea
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• v.29 no.5
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• pp.727-734
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• 2010

The objective of this study was to evaluate the resting postures of the fingers and wrist based on the biomechanical model in term of hand posture (neutral, pronation, and supination) and gender (male and female). The finger and wrist joint angles were measured with VICON motion system. The EMG system was used to examine the muscle activity in the resting condition. The participants consisted of twenty male and twenty female students. The angles of the fingers and wrist were analyzed by means of the coordinate system associated with the International Society of Biomechanics. Hand posture was significant for all the joints. The finger and wrist joint flexed in supination more than in neutral and pronation. The hand posture and gender were not significant for the results of muscle activity, but it had larger muscle activities in supination more than in neutral and pronation.

• The Journal of Korea Robotics Society
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• v.7 no.1
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• pp.1-8
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• 2012

A humanoid robot hand with one thumb and two fingers has been developed. Each finger has the specially designed compact joints, called "MEC Joint", which convert the rotation of a motor to the swing motion of a pendulum. The robot hand with the MEC Joints is compact and relatively light but strong enough to grasp objects in the same manner as human being does in daily activities. In this paper the kinematic model and the torque characteristics of the MEC Joint are presented and compared with the results of the dynamic simulation and the dynamometer test. The dynamic behavior of the thumb and two fingers with MEC Joints are also presented by computer simulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.188-200
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• 2005

Control of a multi-fingered robotic hand is usually based on the theoretical analysis for kinematics and dynamics of fingers and of object. However, the implementation of such analyses to robotic hands is difficult because of errors and uncertainties in the real situations. This article presents the control method for estimating the kinematic constraint of an unknown object by active sensing. The experimental system has a two-fingered robotic hand suspended vertically for manipulation in the vertical plane. The fingers with three degrees-of-freedom are driven by wires directly connected to voice-coil motors without reduction gears. The fingers are equipped with three-axis force sensors and with dynamic tactile sensors that detect slippage between the fingertip surfaces and the object. In order to make an accurate estimation for the kinematic constraint of the unknown object, i.e. the constraint direction and the constraint center, four kinds of the active sensing and feedback control algorithm were developed: two position-based algorithms and two force-based algorithms. Furthermore, the compound and effective algorithm was also developed by combining two algorithms. Force sensors are mainly used to adapt errors and uncertainties encountered during the constraint estimation. Several experimental results involving the motion of lifting a finger off an unknown object are presented.

• Journal of the Ergonomics Society of Korea
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• v.30 no.6
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• pp.749-755
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• 2011

Objective: The purpose of this study is to assess the reducing effect of workload on developed electro-motion scissors. Methods: To achieve this, we measured the pressure distribution, Joint angle of fingers and JSI(Job Strain Index) for electro-motion scissors and hand-operated scissor in objective assessment and surveyed the uncomfortable degree in subjective assessment. Results: As a result, The peak of pressure in the electro-motion scissors was generally lower than the hand-operated scissors. JSI and overall joint angle of fingers for the electro-motion scissors were remarkably lower than the hand-operated scissors. Also, the subjective uncomfortable degree showed that the uncomfortable point of electro-motion scissors were generally lower than the hand operated scissors. Conclusion: The impact of reducing the work load as well as distributing the pressure around the hand by using electro-motion scissors during grapes pinching was confirmed.

• Archives of Reconstructive Microsurgery
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• v.10 no.2
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• pp.143-148
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• 2001

The hand with amputation of all fingers is useless for activities of daily living and traumatic amputation of some of the fingers can result in the diminished ability to perform power grip and precision grip which is vital to maintain normal function of the hand. Precision grip is used to hold an object between the opposable thumb and flexed fingers. In power grip the object is held between the flexed fingers and the palm while the thumb applies the necessary counterpressure to maintain the grip on the object. A 35 year old male lost his right all fingers including thumb at the level of proximal phalanx from the pressure machinary accident. Thumb was reconstructed using wrap around flap and the second and third fingers were reconstructed using the second and third toe transplantation. Seven years after reconstruction, he uses the reconstructed thumb and the second and the third fingers for eating meals, writing down a paper with a pencil and putting on socks.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.9
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• pp.68-76
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• 1997

This paper presents a system which recognizes dynamic hand gestures for virtual reality(VR). A dynamic hand gesture is a method of communication for a computer and human who uses gestures, especially both hands and fingers. Since the human hands and fingers are not the same in physical dimension, the same form of a gestrue produced by two persons with their hands may not have the same numerical values which are obtained through electronic sensors. In this paper, we apply a fuzzy min-max neural network and feature analysis method using fuzzy logic for on-line pattern recognition.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.2
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• pp.61-70
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• 1997

Human-hand gestures have been used a means of communication among people for a long time, being interpreted as streams of tokens for a language. The signed language is a method of communication for hearing impaired person. Articulated gestures and postures of hands and fingers are commonly used for the signed language. This paper presents a system which recognizes the korean sign language (KSL) and translates the recognition results into a normal korean text and sound. A pair of data-gloves are used a sthe sensing device for detecting motions of hands and fingers. In this paper, we propose a dynamic gesture recognition mehtod by employing a fuzzy feature analysis method for efficient classification of hand motions, and applying a fuzzy min-max neural network to on-line pattern recognition.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.341-345
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• 2009

We present an augmented reality (AR) application for cell phone where users put a virtual pet on their palms and play/interact with the pet by moving their hands and fingers naturally. The application is fundamentally based on hand/palm pose recognition and finger motion estimation, which is the main concern in this paper. We propose a fast and efficient hand/palm pose recognition method which uses natural features (e.g. direction, width, contour shape of hand region) extracted from a hand image with prior knowledge for hand shape or geometry (e.g. its approximated shape when a palm is open, length ratio between palm width and pal height). We also propose a natural interaction method which recognizes natural motion of fingers such as opening/closing palm based on fingertip tracking. Based on the proposed methods, we developed and tested the AR application on an ultra-mobile PC (UMPC).