• Journal of the Korean Society for Precision Engineering
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• v.32 no.10
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• pp.873-878
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• 2015

A finger exoskeleton actuated by ionic polymer metal composite (IPMC) actuators has been developed. In order to evaluate performance of cylindrical grasping of finger exoskeletons, they were equipped with a hand dummy, which is composed of four fingers. The finger dummy has three joints that can be actuated by bending the IPMC actuators. A four finger grasping motion was analyzed using cameras, and cylindrical grasping motion was accomplished within two minutes after applying a 4 volt direct voltage to the IPMC actuators. A pull out test was also performed to evaluate the cylindrical grasping force of the finger exoskeletons actuated by the IPMC actuators. Each finger generated about 2 N of holding force when grasping the cylinder which had a diameter of 50 mm.

• The Journal of Korea Robotics Society
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• v.3 no.4
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• pp.315-322
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• 2008

A new soft finger mechanism using a spring as a backbone is proposed in this work. It is a 4 DOF mechanism that consists of a spring and 3 cylinders, which behave like joints with 3 up-and-down rotations and 1 left-and-right rotation. To control each joint, cylinders have small holes in their cross-sectional areas, and wires of different length are penetrated into these holes. We can control each joint by pulling the corresponding wire. The forward kinematics is solved by using the geometry of mechanism. And the relationship (Jacobian) between the linear velocity of the wires and the joint angular rate is obtained. A virtual simulator is developed to test the validity of the kinematic model. In the experiment, first, the position control is conducted by tracking a given trajectory. Second, to verify the flexibility and safety, we show that the soft finger deflects in a safe manner, in spite of the collision with environment.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.846-851
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• 2010

In this paper, we newly propose a novel control strategy of a three joints-robot finger for the purpose of artificial hands. The robot finger is specifically modeled by using a 3D CAD program (CATIA), considering human fingers, and then the proposed control method is verified through the dynamic simulation tool (Simulink and Recurdyn R2). Each slider is individually controlled to be located at the optimal positions where the maximal joint torque can be generated. To prove the effectiveness of the proposed control method, we devise two cases for the reference position of sliders. By comparing the control performance of two cases, the validity of the proposed control method will be verified.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.153-158
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• 2019

The purpose of this study is to compare and analyse the differences between a customized small finger made by 3D printing technology, a real small finger, and the other made from plaster of an orthotic company. The areas and the volumes of each cross-section were measured by Computer tomography(CT) and a 3D scanner and analysis of variance was performed to find out the differences of each shape. The areas of the point of 15.69mm, Distal Interphalangel Joints, were measured 30 times respectively using the caliper toll function of Picture Archiving Communication System(PASC) program. The volumes were measured by Configure Units of Meshmixer Program. There was no significant difference in the areas between three of them and there was 0.2 mm gap in the volume, which was more than the significance probability. Therefore, the result of this study shows the availability of finger orthoses made by 3D printing technology in the medical field.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1585-1591
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• 2011

In this paper, we present a new exoskeleton-type data glove that can sense the movement of the human finger and reflect the force to the finger. The data glove is designed on the basis of the skeletal structure of the human hand, and the finger module has 1 degree-of-freedom because it includes three four-bar mechanism joints in series and a wire-coupling mechanism. In addition, the transmission ratio of the finger module is maintained at 1:1.4:1 over the entire movement range, and hence, the module can perform both extension and flexion. In addition, to enable adduction/abduction motion of the human hand, a unique MCP joint is designed by using two universal joints. To validate the feasibility of the data glove, master-slave control experiments based on force-position control between the data glove and the robot hand are conducted.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.2
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• pp.379-386
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• 2023

When patients suffer from finger injuries, their finger joints can become stiff and inflexible due to decreased ability to exercise the finger tendons. This can lead to a loss of strength and difficulty using their hands. To address this, it is important to provide patients with consistent rehabilitation treatment that can help restore finger flexibility and strength simultaneously. In this study, we propose wearable gloves that use FSRs (force sensitive resistors) for finger strength training. The glove is designed to be adjustable using rubber bands and a custom PCB is designed for signal acquisition. For the evaluation of finger strength training, the result was analyzed in four cases. We suggest a vector that represents the center of five finger forces, and the result shows that the vector can indicate the level of force balance.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.42-48
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• 1999

A control method for a robot hand grasping a object in a partially unknown environment will be proposed, where a proximate sensor detecting the distance between the fingertip and object was used. Particularly, the finger joints were driven servo-pneumatically in this study. Based on the proximate sensor signal the finger motion controller could plan the grasping process divided in three phases ; fast aproach, slow transitional contact and contact force control. That is, the fingertip approached to the object with full speed, until the output signal of the proximate sensor began to change. Within the perating range of the proximate sensor, the finger joint was moved by a state-variable feedback position controller in order to obtain a smooth contact with the object. The contact force of fingertip was then controlled using the blocked-line pressure sensitivity of the flow control servovalve for finger joint control. In this way, the grasping impact could be reduced without reducing the object approaching speed. The performance of the proposed grasping method was experimentally compared with that of a open loop-controlled one.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.7
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• pp.568-577
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• 2000

In this paper for an object grasped by a robot hand to work in stiffness control domain we first investigate the number of fingers for successful stiffness modulation in the object operational space. Next we propose a new compliance control method for robot hands which consist of two steps. RIFDS(Resolved Inter-Finger Decoupling Solver) is to decompose the desired compliance characteristic specified in the op-erational space into the compliance characteristic in the fingertip space without inter-finger coupling and RIJDS(Resolved Inter-Joint Decoupling Solver) is to decompose the fingertip space without inter-finger coupling and RIJDS(Resolved inter-Joint Decoupling Solver) is to decompose the compliance characteristic in the finger-tip space into the compliance characteristic given in the joint space without inter-joint coupling. Based on the analysis results the finger structure should be biominetic in the sense that either kniematic redundancy or force redundancy are required to implement the proposed compliance control scheme, Five-bar fingered robot hands are used as an illustrative example to implement the proposed compliance control method. To show the effectiveness of the proposed compliance control method simulations are performed for two-fingered and three-fingered robot hands.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1374-1377
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• 2008

The aim of this study is to explore the principle that the joints of the limbs belong to Five Phases in Korean medicine. According to the principle of I-Ching, Ha-Do provides the logic which could attach everything to Five Phases. Ha-Do is composed of the numbers from one through ten, and in order to explain the logic of Universe formation, it furnishes the method of transforming 'immateriality' into 'materiality'. If we apply formation theory of Ha-Do to the joints of the limbs, however, it could be understood that the trunk of body develops the appendages, which means Ha-Do suggests a logic that 'materiality' generates 'materiality' in this case. Therefore, it is not the Water but the Earth that occurs first in the appendages development in this theory, and the shoulder joints belong to the Earth. Following development should occur in order of Five Phases formation of Ha-Do ; that is to say, the elbow joints belong to the Water, the wrist joints belong to the Fire, the finger joints belong to the Wood, and the ends of fingers belong to the Metal.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.360-365
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• 2003

In this paper, we have developed a general purpose motion controller using an FPGA(Field Programmable Gate Array). The multi-PID controllers on a single chip are implemented as a system-on-chip for multi-axis motion control. We also develop a PC GUI for an efficient interface control. Comparing with the commercial motion controller LM 629 it has multi-independent PID controllers so that it has several advantages such as space effectiveness, low cost and lower power consumption. In order to test the performance of the proposed controller, robot finger is controlled. The robot finger has three fingers with 2 joints each. Finger movements show that position tracking was very effective. Another experiment of balancing an inverted pendulum on a cart has been conducted to show the generality of the proposed FPGA PID controller. The controller has well maintained the balance of the pendulum.