• 로봇학회논문지
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• 제17권4호
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• pp.484-492
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• 2022

This paper presents a simple and robust under-actuated robotic finger mechanism that enables self-adaptive grip, fingertip pinch, and caging grasp functions. In order to perform daily activities using hands, the fingers should be able to perform adaptive gripping and pinching motion, and the caging grasp function is required to realize natural gripping motions and improve grip reliability. However, general commercial prosthetic hands cannot implement all three functions because they use under-actuation mechanism and simple mechanical structure to achieve light-weight and high robustness characteristic. In this paper, new mechanism is proposed that maintains structural simplicity and implements all the three finger functions with simple one degree-of-freedom control through a combination of a four-bar linkage mechanism and a wire-driven mechanism. The basic structure and operating principle of the proposed finger mechanism were explained, and simulation and experiments using the prototype were conducted to verify the gripping performance of the proposed finger mechanism.

• 한국정밀공학회지
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• 제20권4호
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• pp.158-164
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• 2003

The air circuit breaker (ACB) with the spring-actuated mechanism was studied to improve the fatigue-proof characteristics of its link. The low-cycle fatigue fracture phenomenon occurred on the critical link, called h-link, of ACB from the repeated rapid closing and opening operations. To analyze the cause of failure, dynamic FE-analysis on the b-link part of ACB was performed considering tile velocity and acceleration of the links per time as boundary conditions, which were obtained by using ADAMS. Also, the S-N curve obtained by experiments was used to investigate requirement on the fatigue-proof characteristics. Then, to reduce the maximum tensile stress on the h-link, three types of h-link were examined and one of them was selected.

• 제어로봇시스템학회논문지
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• 제17권12호
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• pp.1248-1255
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• 2011

In daily life, another major role of human hand is a communicative function using hand gestures besides grasp function. Therefore, if amputees can express their intention by the prosthetic hand, they can much actively participate in social activities. Thus, this paper propose myoelectric multi-function prosthetic hand which can express 6 useful hand gestures such as Rock, Scissors, Paper, Indexing, Ok and Thumb-up. It was designed as under-actuated structure to minimize volume and weight of the prosthetic hand. Moreover, in order to effectively control various hand gestures by only two EMG sensors, we propose a control strategy that the signal type are expanded as "Strong" and "Light", and hand gestures are hierarchically classified for the intuitive control. Finally, we prove the validity of the developed prosthetic hand with the experiment.

• 한국항공우주학회지
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• 제33권12호
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• pp.48-53
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• 2005

본 논문에서 LIPCA(Lightweight Piezoceramic Composite Actuator)를 이용한 날갯짓(flapping) 기구의 개발에 관한 최근의 연구진척 사항을 제시하였다. 날갯짓 기구는 여러 개의 연결막대를 이용하여 LIPCA의 제한된 작동변위를 커다란 날갯짓 각(flapping angle)이 발생하도록 증폭시켰으며, 패더링 메커니즘(feathering mechanism)을 적용하여 날갯짓과 동시에 날개에 비틀림이 발생하도록 설계되었다. 이 날갯짓 기구의 고유 날갯짓 주파수는 약 9Hz로, 이때 최대의 날갯짓 각이 발생하였다. 제작된 날갯짓 기구의 작동성능을 평가하기 위하여 날갯짓 주파수를 4Hz에서 15Hz까지 변화시키면서 발생되는 양력과 추력을 측정하였으며, 최대 양력과 최대 추력은 고유 날갯짓 주파수 부근에서 계측되었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.719-722
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• 2005

In this paper, we present out recent progress in the LIPCA (Lightweight Piezo-Composite Actuator) application for actuation of a flapping wing device. The flapping device uses linkage system that can amplify the actuation displacement of LIPCA. The feathering mechanism is also designed and implemented such that the wing can rotate during flapping. The natural flapping-frequency of the device was about 9 Hz, where the maximum flapping angle was achieved. The flapping test under 5 Hz to 15 Hz flapping frequency was performed to investigate the flapping performance by measuring the produced lift and thrust. Maximum lift and thrust were produced when the flapping device was actuated at about the natural flapping-frequency.

• 터널과지하공간
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• 제30권6호
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• pp.591-602
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• 2020

기존의 전통적인 암석절삭방식의 한계점을 극복하고자 다양한 신개념의 암석절삭메커니즘이 연구되고 있으며, 그 중 언더커팅은 최근 연구가 수행되고 있는 기술이다. 본 논문에서는 언더커팅에 대한 기초연구로서 구동형 언더커팅에 의한 암석절삭메커니즘과 절삭에 관여하는 중요핵심변수들에 대하여 소개하였다. 구동형 언더커팅에 의한 절삭성능을 평가하기 위한 시험시스템을 구축하고 이를 활용하여 주요 핵심변수들을 변화시켜가며 구동형 언더커팅 디스크를 활용한 절삭시험을 수행하였다. 구동형 언더커팅 절삭시험으로부터 획득되는 3방향 커터작용력의 특성을 분석하였으며, ADC의 주요 절삭변수인 선형 이동속도, 법선압입깊이, 편심의 증가에 따라 3방향 커터작용력의 평균값과 최댓값은 모두 선형적으로 증가하는 결과를 나타내었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.530-533
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• 1986

A manipulator with 3 degrees of freedom is developed to automate operation of 60 ton pressing process. The pneumatically actuated manipulator is controlled by a programmable controller. Four seconds of cycle time which is faster than manual operation is achieved. Though the flexible feed mechanism, the system can accammodate any size of workpieces between 80*80 and 200*200 under 1 kg of weight.

• 로봇학회논문지
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• 제9권4호
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• pp.258-263
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• 2014

An adaptive robot hand (AR-Hand) has a stable grasp of different objects in unstructured environments. In this study, we propose an AR-Hand based on a tendon-driven mechanism which consists of 4 fingers and 12 DOFs. It weighs 0.5 kg and can grasp an object up to 1 kg. This hand based on the adaptive grasp mechanism is able to provide a stable grasp without a complex control algorithm or sensor system. The fingers are driven by simple tendon structures with each finger capable of adaptively grasping the objects. This paper presents a method to decide the joint stiffness. The adaptive grasping is verified by various grasping experiments involving objects with different shapes and sizes.

• 로봇학회논문지
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• 제19권1호
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• pp.1-7
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• 2024

This paper presents an under-actuated robotic hand inspired by the ligamentous structure of the human hand for a prosthetic application. The joint mechanisms are based on the concept of a tensegrity structure formed by elastic strings. These rigid bodies and elastic strings in the mechanism emulate the phalanx bones and primary ligaments found in human finger joints. As a result, the proposed hand inherently possesses compliant characteristics, ensuring robust adaptability during grasping and when interacting with physical environments. For the practical implementation of the tensegrity-based joint mechanism, we detail the installation of the strings and the routing of the driving tendon, which are related to extension and flexion, respectively. Additionally, we have designed the palm structure of the proposed hand to facilitate opposition and tripod grips between the fingers and thumb, taking into account the transverse arch of the human palm. In conclusion, we tested a prototype of the proposed hand to evaluate its motion and grasping capabilities.

• 제어로봇시스템학회논문지
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• 제20권10호
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• pp.1008-1013
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• 2014

This paper introduces an adaptive anti-sway tracking control algorithm for container cranes with unknown payloads and friction between the trolley and the rail. If the friction effects in the system can be modeled, there is an improved potential to design controllers that can cancel these effects. The proposed control improves the sway suppressing and the positioning capabilities of the trolley and hoisting against uncertain payload and friction. The variable structure controls are first designed based on a class of feedback linearization methods for the stabilization of the under-actuated sway dynamics. The adaptation mechanism are then designed with parameter estimation of unknown payload and friction compensation for the trolley and hoisting, based on Lyapunov stability methods for the accurate positioning and fast attenuation of trolley oscillation due to frictions in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulations are shown under various frictions and external winds in the case of no priori information of payload mass.