• 한국정밀공학회지
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• 제28권6호
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• pp.657-682
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• 2011

This paper presents the dynamic analysis on the joint torque of a finger for the tip pinch task. The dynamic model on finger movement was developed in order to predict the joint torques of an index finger, and the finger was assumed as a three-link planar manipulator. Analysis of the model revealed that the joint stiffness was one of the most important parameters affecting the joint torque. The stiffness of the finger joint was experimentally measured, and it was used in analyzing the finger joint torque required for performing the tip pinch task. The obtained joint torque for the tip pinch task will be used as the design requirements of the finger exoskeletal orthosis actuated by the polymer actuator whose allowable torque limit is relatively low compared to that of a mechanical actuator.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.149-154
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• 2015

Biometric techniques for authentication using body parts such as a fingerprint, face, iris, voice, finger-vein and also photoplethysmography have become increasingly important in the personal security field, including door access control, finance security, electronic passport, and mobile device. Finger-vein images are now used to human identification, however, difficulties in recognizing finger-vein images are caused by capturing under various conditions, such as different temperatures and illumination, and noise in the acquisition camera. The human photoplethysmography is also important signal for human identification. In this paper To increase the recognition rate, we develop camera based identification method by combining finger vein image and photoplethysmography signal. We use a compact CMOS camera with a penetrating infrared LED light source to acquire images of finger vein and photoplethysmography signal. In addition, we suggest a simple pattern matching method to reduce the calculation time for embedded environments. The experimental results show that our simple system has good results in terms of speed and accuracy for personal identification compared to the result of only finger vein images.

• 한국정밀공학회지
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• 제31권7호
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• pp.643-649
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• 2014

In order to demonstrate the possibility of applying an ionic polymer metal composite (IPMC) to a finger exoskeleton, pinching motion analysis was performed for a thumb-index finger dummy actuated by IPMC actuators. The IPMC actuators of 5mm in width and 40mm in length with 2.4mm thickness generated 1.52N of blocking force for the applying voltage of 4.0V. Three actuators were installed on the three rotary joint of an index finger, and one actuator was installed on one proximal joint. Positions of each joint and finger tip were recorded on the video camera, and motion was analyzed. Power supply to the index finger actuators preceded power supply to the thumb actuator, and key pinching motion was accomplished in 180s. Tip pinching was accomplished in 135s as power supply to the thumb preceded power supply to the index finger.

• 한국정밀공학회지
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• 제29권7호
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• pp.717-722
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• 2012

This paper presents the design and dynamic model of the finger exoskeleton actuated by Ionic Polymer Metal Composites (IPMC) to assist a tip pinch task. Although this exoskeleton will be developed to assist 3 degree-of-freedom motion of each finger, it has been currently made to perform the tip pinch task using 1 degree-of-freedom mechanism as the first step. The six layers of IPMC were stacked in parallel to increase the low actuation force of IPMC. In addition, the finger dummy was manufactured to evaluate the performance of the finger exoskeleton. The pinch task experiments, which were performed on the finger dummy with the developed exoskeleton, showed that the pinch force close to the desired level was obtained. Moreover, the dynamic model of the exoskeleton and finger dummy was developed in order to perform the various analyses for the improvement of the exoskeleton.

• 대한기계학회논문집B
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• 제41권2호
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• pp.125-133
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• 2017

본 연구에서는 환자의 손가락 경직을 모사하는 손가락 시뮬레이터를 통해 손가락 경직도 검진에서의 검진자간 신뢰도에 대해 연구하였다. 시뮬레이터를 제어하기 위해 경직에서 나타나는 토크를 간단하게 모델링 하고 손가락 경직 환자로부터 간단한 측정 모듈을 이용해 각각의 Modified Ashworth Scale(MAS) 등급에 맞는 파라미터를 얻어냈다. 또한 중수지 관절에 모터가 위치한 손가락 형태의 로봇을 설계하여 경직 토크 모델을 따르는 시뮬레이터를 개발하였다. 이 시뮬레이터를 통해 일곱 명의 재활의학과 전문의들의 검진 결과를 평가해본 결과 중수지 관절에서 0.619, 근위지간 관절에서 0.514의 Cohen's Kappa 값을 보였다. 검진자간의 Fleiss' Kappa 값은 중수지 관절에서 0.513, 근위지간 관절에서 0.486으로 나타났다. 또한 검진자들은 각각의 주관적인 MAS 검진 기준을 가진다는 것을 확인하였다. 결과적으로 같은 환자에 대한 MAS 검진 신뢰도가 높지 않기 때문에 개발된 로봇 시뮬레이터는 검진자의 신뢰도를 높일 수 있는 교육용 도구로서 활용 가능함을 확인하였다.

• 한국정밀공학회지
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• 제32권10호
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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.

• Tribology and Lubricants
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• 제26권3호
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• pp.184-189
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• 2010

In this paper, tactile response characteristics in medical haptic interface are investigated to characterize the feeling of contact between the finger skin and the organic tissue when a finger is dragged over tissue. In order to represent the tactile feeling, a prototype tactile display incorporating Magneto-Rheological (MR) fluid has been developed. Tactile display devices simulate the finger's skin to feel the sensations of contact such as compliance, curvature and friction. Thus, the tactile display provides the surface information of organic tissue to the surgeon using different actuating mechanisms ranging from the conventional mechanical motor to the smart material actuators. In order to investigate the compliance feeling of human finger's touch, vertical force responses of the tactile display under the various magnetic fields have been assessed. Also, frictional resistive force responses of the tactile display are investigated to simulate the action of finger's dragging. From the results, different tactile feelings are observed as the applied magnetic field is varied and arrayed magnetic poles combinations. This research gives a smart technology of tactile displaying.

• 대한기계학회논문집A
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• 제29권2호
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• pp.176-187
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• 2005

This paper presents an evaluation of joint configurations of a robotic finger based on kinematic analysis. The evaluation is based on an assumption that the current control methods for the fingers require that the contact state specified by the motion planner be maintained during manipulation. Various finger-joint configurations have been evaluated for different contact motions. In the kinematic analysis, the surface of the manipulated object was represented by B-spline surface and the surface of the finger was represented by cylinders and a half ellipsoid. Three types of contact motion, namely, 1) pure rolling, 2) twist-roiling, and 3) slide-twist-rolling are assumed in this analysis. The finger-joint configuration best suited for manipulative motion is determined by the dimension of manipulation workspace. The evaluation has shown that the human-like fingers are suitable for maintaining twist-rolling and slide-twist-rolling but not for pure rolling. A finger with roll joint at its fingertip link, which is different from human fingers, proved to be better for pure rolling motion because it can accommodate sideway motions of the object. Several kinds of useful finger-joint configurations suited for manipulating objects by fingertip surface are proposed.

• Tribology and Lubricants
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• 제28권5호
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• pp.240-245
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• 2012

In this study, we developed a new carrier finger to prevent scratches in a sheet metal forming line. The developed carrier finger was designed to have a streamlined shape with a larger radius of curvature at the edges, as well as a smaller contact area. To evaluate the scratch alleviation effect, a sliding contact analysis and scratch test using the pin on a plate wear tester were conducted for both the old and new carrier fingers. The results show that, for both transverse and longitudinal movements of the strip, the newly designed carrier finger reduces both the friction and scratch depth by its streamlined shape, which decreases the pressure spike at the edge.

• 반도체디스플레이기술학회지
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• 제10권2호
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• pp.73-81
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• 2011

We manufactured the inkjet printing system for the application into the nano Ag finger line interconnection process in Si solar cells. The home-made inkjet printer consists of motion part for XY motion stage with optical table, head part, power and control part in the rack box with pump, and ink supply part for the connection of pump-tube-sub ink tanknozzle. The ink jet printing system has been used to conduct the interconnection process of finger lines on Si solar cell. The nano ink includes the 50 nm-diameter. Ag nano particles and the viscosity is 14.4 cP at $22^{\circ}C$. After processing of inkjet printing on the finger lines of Si solar cell, the nano particles were measured by scanning electron microscope. After the heat treatment at $850^{\circ}C$, the finger lines showed the smooth surface morphology without micropores.