• 자연과학논문집
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• 제5권1호
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• pp.87-93
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• 1992

비구조적인 환경에서 평면패렛을 포크리프트로 로딩하거나 보조필드 재료운송시스템 로보트를 제안한다. 시스템은 패렛의 위치와 방향을 정의하고 패렛의 2개의 구멍의 위치를 결정하기 위해서 결합된 어쿠스틱과 비쥬얼 센싱 데이타를 사용한다. 그 결과 포크리프트를 패렛의 2개의 구멍에 접근하고 운송하기 위해서 패렛을 인게즈한다. 재료운송시스템의 복잡성을 줄이기 위해서 2차원 포라로이드 울트라소닉 센서와 2차원 압티컬 카메라 비쥬얼 센서데이타를 통합하는 시스템을 개발한다. 2개의 다른 소스에서 얻은 데이타는 서로서로 보완하고 재료운송 시스템로보트를 제어하기 위한 효율적인 알고리즘에 사용한다. 2개의 선형스켄닝으로 부터 얻은 레인지 데이타는 least-mean square 방법을 사용하여 패렛의 팬과 틸트각도를 결정하기 위해서 사용한다. 그리고 에지탐지와 Hough 트랜스폼기술을 사용하여 스윙각도와 패렛의 인게이지먼트 위치를 결정하기 위해서 비쥬얼 데이타를 사용한다. 팬과 틸트각도를 결정하기 위해서 발생하는 제안을 논의한다. 개발된 시스템은 하드웨어와 소프트웨어 구현하여 평가하고 실험적인 결과도 나타낸다.

• 제어로봇시스템학회논문지
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• 제21권5호
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• pp.421-426
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• 2015

Need to develop human body's posture supervised robots, gave the push to researchers to think over dexterous design of exoskeleton robots. It requires to develop quantitative techniques to assess human motor function and generate the command to assist in compliance with complex human motion. Upper limb rehabilitation robots, are one of those robots. These robots are used for the rehabilitation of patients having movement disorder due to spinal or brain injuries. One aspect that must be fulfilled by these robots, is to cope with uncertainties due to different patients, without significantly degrading the performance. In this paper, we propose chattering free sliding mode control technique for this purpose. This control technique is not only able to handle matched uncertainties due to different patients but also for unmatched as well. Using this technique, patients feel active assistance as they deviate from the desired trajectory. Proposed methodology is implemented on seven degrees of freedom (DOF) upper limb rehabilitation robot. In this robot, shoulder and elbow joints are powered by electric motors while rest of the joints are kept passive. Due to these active joints, robot is able to move in sagittal plane only while abduction and adduction motion in shoulder joint is kept passive. Exoskeleton performance is evaluated experimentally by a neurologically intact subjects while varying the mass properties. Results show effectiveness of proposed control methodology for the given scenario even having 20 % uncertain parameters in system modeling.

• 센서학회지
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• 제5권5호
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• pp.55-62
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• 1996

본 논문에서는 개발된 편광방식 스테레오 모니터링(KAERI-PSM) 시스템의 성능을 평가하기 위해 6 D.O.F의 퓨마 로보트를 이용한 원격조작 실험을 수행하였다. 카메라의 관측각도를 달리하는 3가지 원격조작실험은 6명의 실험자가 힘반향 조이스틱을 사용하여 로보트 암을 (1) 직접 (2) 일반 모니터 (3) 동기방식 스테레오 영상 모니터 및 (4) 개발된 편광방식 스테레오 영상 모니터를 통하여 보면서 6가지의 조합된 방법으로 총 36번 수행하여 걸린 평균 시간과 평균 에러 발생 수를 비교하는 것이다. 실험 결과 스테레오 영상 모니터를 사용한 원격작업은 일반 모니터를 이용했을 때 보다 훨씬 짧은 시간에 정확히 수행할 수 있었으며, 물체 이동에 대한 카메라의 각도가 실험의 주요한 변수가 됨을 알 수 있었다. 또한 동기방식과 편광방식의 비교에서 속도와 정확도 면에서는 두 방식이 비슷했으나 눈의 피로도로 인한 작업의 안정성 측면에서는 편광방식이 우수함을 알 수 있었다.

• 제어로봇시스템학회논문지
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• 제17권1호
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• pp.31-37
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• 2011

Recently gantry-type robot with 3 axes rectangular coordinates have been studied in the many industrial production equipment and machinery fields. To acquire a good handling and motion performance of this robot, reducing the settling-time and securing the accurate-transfer positioning under high-speed conditions should be required. However when robot is moved in high-speed, the large inertia of robot can lead to serious vibration of robot's head. The time-delayed control characteristics of this robot can also lead to tracking error. In this research, the analysis of the effects of higher order positional-profile is carried out to assure high-speed performance and stiffness specifications. To remove the residual vibration caused by kinematic coupling effect of dual-servo gantry, we develop a dual-servo gantry of rotary type that moving frame of x-axis rotates about z-axis. In order to decrease the tracking error, the 3 type lead-filter through system identification was applied respectively. From the experimental results, it was shown that zero-order series leader-filter has the best performance about tracking error and settling time.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1116-1120
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• 2004

In the nuclear power plant, there are several cylindrical vessels such as reactor vessel, pressuriser and so on. The vessels are usually constructed by welding large rolled plates, forged sections or nozzle pipes together. In order to assure the integrity of the vessel, these welds should be periodically inspected using sensors such as ultrasonic transducer or visual cameras. This inspection is usually conducted under water to minimize exposure to the radioactively contaminated vessel walls. The inspections have been performed by using a conventional inspection machine with a big structural sturdy column, however, it is so huge and heavy that maintenance and handling of the machine are extremely difficult. It requires much effort to transport the system to the site and also requires continuous use of the utility's polar crane to move the manipulator into the building and then onto the vessel. Setup beside the vessel requires a large volume of work preparation area and several shifts to complete. In order to resolve these problems, we have developed an underwater mobile robot guided by the laser pointer, and performed a series of experiments both in the mockup and in the real reactor vessel. This paper introduces our robotic inspection system and the laser guidance of the mobile robot as well as the results of the functional test.

• 한국항공운항학회지
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• 제11권1호
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• pp.5-16
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• 2003

The present study was carried out to develop highly efficient RC ornithopter 'Songgolmae' powered by motor and battery. Designed electric ornithopter, which has the dimension of O.88m(W)${\times}$0.56m(L)${\times}$0.15m(H), is smaller than a conventional ornithopter. This ornithopter weighs 277 grams and has 3 channels radio control. It runs on an electric motor by a lithium polymer battery and has a gear ratio of about 75${\sim}$95 to 1 to flap its 88 cm wingspan. The aerodynamic performance of the ornithopter, applied to a flapping motion only, was validated by flight tests. Flight times have exceeded 23 minutes until the battery was used up. The flight test results indicate that the ornithopter developed here has sufficient thrust to propel itself in a forward flight. From the economical point of view and the handling of the RC ornithopter, it can be said that the developed robot ornithopter is an effective RC ornithopter. This robot ornithopter flies its way high into the sky just like a real bird flies. The robot ornithopter is used for a wide range of missions.

• 한국산업융합학회 논문집
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• 제18권4호
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• pp.216-223
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• 2015

Recently Manipulation capability is important for a robot. Interaction between a robot hand and objects can be properly controlled only is suitable sensors are available. Recently the tendency is to create robot hands more compact and high integrated sensors system, in order to increase the grasping capability and in order to reduce cabling through the finger, the palm and the arm. As a matter of fact, miniaturization and cabling harness represents a significant limitation to the design of small sized embedded sensor. Ongoing work is focusing on a flexible manipulation system, which consists of a dual flexible multi-fingered hand-arm system, and a dual active vision system.

• 한국공작기계학회논문집
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• 제14권4호
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• pp.81-88
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• 2005

This paper attempts to derive the dynamic model of handling tasks in finger robot which grasps stable and manipulates a rigid object with some dexterity. Firstly, a set of differential equation describing dynamics of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. Secondly, the roblems of controlling both the forces of pressing object and the rotation angle of the object under the geometric constraints are discussed. The effect of geometric constraints of area-contacts between the link's end-effector and the object is analyzed and the model based on the differential-algebraic equations is presented. In this paper, the control method for dynamic stable grasping and enhancing dexterity in manipulating things is proposed. It is illustrated by computer simulation and the experiment that the control system gives the performance improvement in the dynamic stable grasping and nimble manipulating of the dual fingers robot with soft tips.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.219-224
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• 2002

This paper aims to derive a mathematical model of the dynamics of handling tasks in robot finger which stable grasping and manipulates a rigid object with some dexterity. Firstly, a set of differential equation describing dynamics of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. Secondly, problems of controlling both the internal force and the rotation angle of the grasped object under the constraints of area-contacts of tight area-contacts are discussed. The effect of geometric constraints of area-contacts on motion of the overall system is analyzed and a method of computer simulation for overall system of differential-algebraic equations is presented. Thirdly, simulation results are shown and the effects of geometric constraints of area-contact is discussed. Finally, it is shown that even in the simplest case of dual single D.O.F manipulators there exists a sensory feedback from sensing data of the rotational angle of the object to command inputs to joint actuators and this feedback connection from sensing to action eventually realizes secure grasping of the object, provided that the object is of rectangular shape and motion is confined to a horizontal plane.

• 로봇학회논문지
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• 제19권1호
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• pp.31-38
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• 2024

A mobile manipulator is capable of handling a wide range of workspaces by overcoming the limitations of mobility inherent in existing fixed-base manipulators. To simulate the mobile manipulator, two contact operations should be considered in the physics engines. One of these operations is the grasp stability between the gripper and the object, while the other involves the contact between the wheels of the mobile robot and the ground during driving. However, it is still difficult to choose an appropriate physics engine for simulating these contact operations of the mobile manipulator. In this paper, the performance of physics engines for simulating the mobile manipulator is evaluated. Firstly, the grasp stability of the physics engine is quantitatively evaluated based on the contact force discontinuity. Secondly, when the mobile robot is controlled by open or closed-loop control methods, differences in the path taken by the mobile robot depending on the physics engine are analyzed. To assess the performance of robot simulation, three dynamic simulators-MuJoCo, CoppeliaSim, and IsaacSim-are used along with five physics engines: MuJoCo, Newton, ODE, Bullet, and PhysX.