• 한국정밀공학회지
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• 제16권2호통권95호
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• pp.130-137
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• 1999

In this paper we propose a method of determining the local curvature of a three dimensional convex object using the force and torque information obtained from the active touch of a robot hand. A technique for estimating two dimensional curvature of a convex object are introduced and the way of computing the three dimensional curvature from the two dimensional vurvatures is presented. Also, we develop an experimental system consisting of a finger and verify the effectiveness of the proposed method experimentally.

• 대한기계학회논문집A
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• 제27권8호
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• pp.1259-1265
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• 2003

We present a new post-fabrication frequency tuning method for laterally driven electrostatic microresonators using a DC-biased electrostatic comb array of linearly varied finger-length. The electrostatic tuning force and the equivalent stiffness, adjusted by the DC-biased tuning-comb array, have been formulated as functions of geometry and DC tuning voltage. A set of frequency-turnable microresonators has been designed and fabricated by 4-mask surface-micromachining process. The resonant frequency of the microfabricated microresonator has been measured for a varying tuning voltage at the reduced pressure of 1 torr. The maximum 3.3% reduction of the resonant frequency is achieved at the tuning voltage increase of 20V.

• 한국구조물진단유지관리공학회 논문집
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• 제22권6호
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• pp.170-175
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• 2018

내진 성능 학보를 위해서는 신축이음장치가 지진력에 대하여 적절한 변형이 발생하여 신축이음장치의 파괴를 방지하여야 하는데 최근에 국내에서 신축이음장치의 핑거부에 힌지를 설치하여 교축방향의 지진력에 대한 변위 저항성을 확보한 신제품이 개발되고 있다. 이에 본 논문에서는 가변형 핑거 조인트를 가지는 신축이음장치에 대하여 실물규모의 교축직각방향 하중에 대한 저항성을 실험적으로 평가하였다. 실험결과, 최대 수평변위는 기존 신축이음 실험체의 경우 약 21.1mm, 내진 신축이음 실험체의 경우 51.00mm로 나타났으며, 기존제품은 추가적으로 16.5mm의 솟음이 발생되었다. 기존 신축이음 실험체는 어느 정도의 교축직각 방향의 하중에 대하여 저항한 후, 핑거의 휨 및 전단 변형이 과도하게 발생되며 파단 현상이 발생할 가능성이 있을 것으로 추정된다. 반면에 내진 신축이음 실험체의 경우, 교축 직각방향의 하중에 대하여 하중에 대한 변형을 핑거의 힌지가 흡수하여 신축이음장치 및 상부구조에 응력을 발생시키지 않고 다만 하중 작용방향으로의 수평 변형만 발생시킬 것으로 예상된다.

• 한국의류산업학회지
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• 제11권5호
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• pp.764-770
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• 2009

This study was conducted to analyze the wearing condition on gloves for pilots and to suggest the developments for pilot gloves design. This survey was performed with 99 pilots and the questionnaires included items about discomfort, materials and problems when wearing pilot gloves. The respondents felt uncomfortable on the finger tip, the hollow area of the hand and the end of thumb when they move their hands with the gloves. They replied that the finger length, palm length, and circumference of the fingers did not match well. Also they complained there was severe abrasion in the tip of the thumb, finger tips and the middle of the palm of the gloves. The result of these analyses supports the following suggestions. It is necessary to improve durability by applying the additional materials to the severely worn parts. Punching on the glove materials could improve sweat rate and ventilation, and careful washing should be accompanied to prevent the occurrence of linters and transformation after laundering. And it is needed to prepare an accurate and more diversified size system and to design the gloves fitted to the individual hands. With these in mind, it is required to propose solutions for pilot gloves with reference to the survey results in order to design appropriate pilot gloves in terms of movement, size and material. It was concluded that an analysis of the wearing condition and developments are useful for ergonomics pilot gloves design.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.246-250
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• 2003

In this study, two new types of micro-grippers in which micro-fingers are actuated by piezoelectric multi-layer benders and stacks are introduced for the manipulation of micrometer-sized objects. First, we constructed a 3-chopstick-mechanism tungsten gripper, which is composed of three chopsticks: two are designed to grip micro-objects, and tile third is used to help grasp and release the objects through overcoming especially electrostatic force among some surface effects including electrostatic, van der Waals forces and surface tension. Second, a 2-chopstick-mechanism silicon micro-gripper that uses an integrated force sensor to control the gripping force was developed. The micro-gripper is composed of a piezoelectric multilayer bender for actuating the gripper fingers, silicon fingertips fabricated by use of silicon-based micromachining, and supplementary supports. The micro-gripper is referred to as a hybrid-type micro-gripper because it is composed of two main components; micro-fingertips fabricated using micromachining technology to integrate a very sensitive force sensor for measuring the gripping force, and piezoelectric gripper finger actuators that are capable of large gripping forces and moving strokes. The gripping force signal was found to have a sensitivity of 667 N/V. To the design of each of components of both of the grippers. a systematic design approach was applied, which made it possible to establish the functional requirements and design parameters of the micro-grippers. The micro-grippers were installed on a manual manipulator to assess its performance in tasks such as moving micro-objects from one position to a desired position. The experiment showed that the micro-grippers function effectively.

• 인터넷정보학회논문지
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• 제17권6호
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• pp.41-51
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• 2016

3D-Touch 인터페이스의 등장은 사용자로 하여금 새로운 인터랙션을 제공할 수 있는 기반을 마련해 주었다. 하지만 일부 스마트폰에서만 3D-Touch가 제공되고 있고, 대부분 2D-Touch 스마트폰에서 사용되는 인터랙션 방법은 새로운 방식의 3D-Touch의 인터랙션을 제대로 적용할 수 있는 방안은 마련되지 않고 있다. 이는 3D-Touch와 2D-Touch 인터랙션에서의 차이가 발생하는 주요 원인이다. 이에 따라 본 연구에서는, 2D-Touch 기반 디바이스에서도 3D-Touch의 소프트웨어적 기능과 인터페이스를 활용할 수 있게 해주는 가상 포스 터치 (Virtual Force Touch) 방식을 이용해서 3D-Touch 인터페이스를 활용할 수 있는 방안에 대하여 제안한다. 제안한 방안은 2D-Touch를 제공하는 스마트폰에서 사용자가 포스터치 입력을 발생하였을 때 스마트폰에 차지하는 손가락 면적을 분석하여 적절한 가상 포스 터치 구현하기 위한 것이다.

• 한국컴퓨터정보학회논문지
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• 제22권9호
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• pp.65-71
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• 2017

This paper proposes a smart phone authentication method based on user's behavior and habit that is an authentication method against shoulder surfing attack and brute force attack. As smart phones evolve not only storage of personal data but also a key means of financial services, the importance of personal information security in smart phones is growing. When user authentication of smart phone, pattern authentication method is simple to use and memorize, but it is prone to leak and vulnerable to attack. Using the features of the smart phone pattern method of the user, the pressure applied when touching the touch pad with the finger, the size of the area touching the finger, and the time of completing the pattern are used as feature vectors and applied to user authentication security. First, a smart phone user models and stores three parameter values as prototypes for each section of the pattern. Then, when a new authentication request is made, the feature vector of the input pattern is obtained and compared with the stored model to decide whether to approve the access to the smart phone. The experimental results confirm that the proposed technique shows a robust authentication security using subjective data of smart phone user based on habits and behaviors.

• 대한기계학회논문집A
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• 제29권2호
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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.

• 한국생산제조학회지
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• 제24권1호
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• pp.81-86
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• 2015

This paper presents a disposable passive suction pump that uses the restoring force of an elastomeric chamber for liquid transportation in a microfluidic system. The proposed suction pump can be operated by finger pressure without any peripheral equipment. To adjust the generated suction pressure, five different displacements of the suction chamber ceiling, two different chamber shapes, and five different elastic moduli of the elastomer were considered. For a cylindrical chamber with a 5 mm height and 5 mm radius, the generated suction pressure and flow rate increased almost linearly up to about 31 kPa and $160.8{\mu}L/min$, respectively, depending on the chamber deformation. A maximum suction pressure of $42.9{\pm}0.7kPa$ was obtained for a hemispherical chamber with a 2.1 mm height and 5 mm radius.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1996년도 춘계학술발표회 초록집
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• pp.73-87
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• 1996

The outer-most electrons of metal atoms and the remining valence electrons of any molecular atoms make three dimensional crystallizing $\pi$-bondings. The electrons on the $\pi$-bonding orbital rotate clockwise or counter-clockwise and they then make electro-magnetic waves between atoms on the orbital because electron move between plus charged ions. The three dimensional crystallizing $\pi$-bonding orbitals are quantum-mechanically modeled by a cyclic Kronig-Penny Model and energy band structures are analyzed with their potential barrier thickness. The waves generated between plus charged ions are the particular $\pi$-far infrared rays, which have dual properties between material and electro-magnetic waves and can be measured not by modern electro-magnetic tester but biosensor such as finger's force tester. Because the $\pi$-rays can be modulated with electro-magnetic waves it can be applied for harmful electro-magnetic wave killers. Because the $\pi$-rays make new three dimensional crystallizing $\pi$-bonding orbitals in the material the food and drink can be transformed into a helpful physical constitutional property for human health. Distinction between crystalline and amorphous metals is possible because very strong crystalline $\pi$-bonding orbitals can not easily be transformed into another. The $\pi$-rays can also be applied for biofunctional diagnostics and therapy. Gravitational field is one of the electro-magnetic fields. And also magnetic field and gravitational force field make charge's movement. ($\times$ = q, : magnetic field, : force field, q: plus charge, : velocity field)