• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.1
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• pp.46-50
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• 2013

This paper proposes an adaptive fault accommodation control approach for flexible-joint (FJ) robots with multiple actuator faults. It is assumed that the value and occurrence time of multiple actuator faults are unknown. An adaptive fault accommodation control scheme with prescribed performance bounds, which characterize the convergence rate and maximum overshoot of tracking errors, is designed to accommodate the actuator faults. From the Lyapunov stability theorem, it is proved that all signals of the closed-loop system are semi-globally uniformly ultimately bounded and tracking errors are preserved within prescribed performance bounds regardless of actuator faults.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.8
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• pp.505-510
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• 2017

This paper presents a low-cost robotic device for shoulder rehabilitation, which is capable of treating various shoulder disabilities. A 3-DOF passive shoulder joint tracking module was designed to allow for translational motion of the shoulder joint center during arm swing, which is essential for natural shoulder movement. The weight of the user's arm and the device were compensated for by springs, to enable gravity-free shoulder motion. In order to reduce the device's cost, only one actuator was used, which can be aligned with the user's shoulder joint in various orientations. The device is capable of implementing five representative shoulder motions, including flexion/extension, abduction/adduction, horizontal abd/adduction, internal/external rotation, and oblique raise. The proposed low-cost shoulder rehabilitation robot is expected to provide effective rehabilitation for patients with various shoulder impairments.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.525-528
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• 2021

본 논문은 산업현장이 아닌 카페등 생활현장에서의 폐기용 컵 처리를 목적으로, 사람을 대신해 지능적이고 기구학적으로 효율적인 다관절 메니퓰레이터의 설계 방법을 연구하였다. 다양한 장소에서 인간을 대신하여 임의의 위치에 있는 다양한 폐기 컵을 3D 카메라로 인식하여 알맞은 위치로 분리수거하는 6축 수직 다관절 모듈형 매니퓰레이터의 안정적인 동작을 위하여 기구부를 Yaw-Pitch-Pitch-Pitch-Yaw-Yaw의 6축 구조로 설계하고, 이를 구동하기 위한 관절 구동기의 용량을 분석하여 관절 구동기를 선정하며 전체적인 이해와 효율적인 분석을 위해 기구 전체의 외관을 3D 모델링 프로그램을 이용하여 구현하고 동작을 검증하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1987.06a
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• pp.41-49
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• 1987

관절 로보트를 위시한 각종 매니퓨레이터 장치의 관절 구동부는 모터와 감속기의 조합으로 구성되어 있다. 최근에는 감속기를 내재하지 않는, 직접구동 방식이 연구중이지만 모터는 고속회전율 시키는 것이 동력밀도가 크기 때문에 대부분 감속기를 사용하여 회전속도를 감속하고 토오크를 증대하여 매니퓨레이터를 구동시키고 있다. 본 연구에서는 내접 유성식 감속기의 국산화를 도모하기 위하여 원통형 핀을 내치차 치형으로 사용한 내접 유성식 감속기의 설계 기술을 개발하였다. 치형 수정계수를 도입하여 수정계수 변화에 대한 치형의 변화와 접촉 하중 및 응력의 변화를 검토하고 로오크 전달시 기구에 작용되는 하중을 해석하여 내접 유성식 감속기의 설계 기법을 제시하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.2
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• pp.147-152
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• 2016

Shape Memory Alloys (SMAs) undergo changes in shape and hardness when heated or cooled, and do so with great force. Since wire-type SMAs contract in length when heated and pull with a surprisingly large force and move silently, they can be used as actuactors which replace motors. These SMA actuators can be heated directly with electricity and can be used to create a wide range of motions. This paper presents the mechanical design and control for a three fingered, six degree-of-freedom robotic hand actuated by SMA actuators. Each finger has two joints and each joint is actuated with two tendons in the antagonistic manner. In order to create the sufficient force to make the smooth motion, the tendon is composed of two SMA actuators in parallel. For controlling the current to heat the SMA actuators, PWM drivers are used. In experiments, the antagonistic interaction of fingers are evaluated.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.814_815
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• 2009

본 논문은 로봇관절 구동 및 제어에 활용될 중공모터의 설계 및 특성해석에 대해 연구하였다. 로봇관절에 사용될 중공모터의 경우고 토크출력이 요구될 뿐만 아니라, 저속에서 제어 및 구동 신뢰성이 높은 운전특성이 요구된다. 또한 로봇 관절에 활용하기 위하여 배선처리가 간편한 중공타입의 구조가 요구된다. 따라서 우리는 로봇 구동 및 경량화가 가능하도록 유성기어와 결합이 가능한 외전형 타입의 영구자석 동기전동기의 설계 및 특성해석을 하였다. 먼저 로봇 관절에 적합하도록 FEA 기법을 이용하여 설계하였으며, 실제 시작기 모델을 제작하여 성능실험을 통해 제안된 모터의 특성을 분석하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.2
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• pp.226-232
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• 2009

In this paper, a design and analysis of a gravity compensator which is a new device to reduce the joint torque of robots caused due to gravity is presented. Joints of all robots are loaded by large torques due to gravity. By applying the gravity compensator to the robot joints, the load torques applied to the robot joints are reduced by the repulsive force of the gravity compensator such that the size of the joint actuation motor can be reduced. In this paper, the structure and force relation of the gravity compensator are analyzed. The superior performance of the proposed gravity compensator is verified through experiments which measure the joint motor current caused by the load applied to the robot link.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1107-1114
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• 2010

In this paper, a development of a new 5 d.o.f. underwater manipulator which is actuated by electric motors capable of carrying over 20kg payload and of various operation under the water has been studied. The manipulator for applying to midium-sized AUV or ROV has been designed small and light but to handle a heavy 25kg payload. The joint actuator for the manipulator is designed and builted as a new modular typed double oil jacket for waterproofness. Also, superior joint torque performance of the developed joint actuator has been varified through tests in the air. And, a 5 d.o.f. highly perfomable underwater manipulator has been builted applying the developed underwater joint actuators.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.503-515
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• 2011

We developed a walking-assistance robot for walking rehabilitation and assessed the kinematic characteristics of a prototype. The walking-assistance robot is composed of hip, knee, and ankle joints, and each joint is driven by a motor with a decelerator. The equations of angular displacement while walking were derived by theoretically analyzing human locomotion, and the calculated angular displacements were then applied to the robot controller. The output angular displacement of each joint was measured and compared with its input angular displacement in walking experiments on a treadmill at various walking speeds and strides. The differences between the input and output angular displacements are 5.22% for the hip and 2.97% for the knee joints, and it has been confirmed that the walking-assistance robot works well.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.1
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• pp.31-38
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• 1999

In this paper, we proposed a fuzzy sliding mode controller for a robot manipulator with passive joints. A robot manipulator with passive joints which is not equipped with actuators is a kind of underactuated systerms. The control of underactuated manipulators is more difficult than that of fully-actuated ones. Though the sliding mode control technique has a robust charocteristics to prrarreter uncertainties and external disturbances, the chattering phenomena becorne one of the major problems in application to the real plant. plant.