• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권10호
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• pp.588-593
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• 2017

본 논문에서는 자율주행차량에서 사용되는 고가의 다채널 라이다(LiDAR) 센서를 다수의 저가 소채널 라이다들로 대체하여 사용하는 경우에 다수의 라이다들을 하나의 라이다로 가상화하는 드라이버를 제안한다. 이를 통해 로봇 분야에서 하나의 물리 라이다를 가정하여 개발된 SLAM(Simultaneous Localization And Mapping) 알고리즘들은 수정 없이 사용될 수 있다. 본 논문은 제안하는 드라이버를 로봇운영체제 ROS(Robot Operating System) 상에서 구현하고 SLAM 알고리즘과 함께 평가하였다. 평가 결과, 제안한 드라이버는 3차원 점지도의 점밀도를 제어하는 필터와 함께 기존 알고리즘의 수정 없이 사용될 수 있음을 확인하였다.

• 로봇학회논문지
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• 제15권4호
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• pp.323-329
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• 2020

This paper presents a control algorithm for a wearable walking aid robot for subjects with paraplegia after stroke. After a stroke, a slow, asymmetrical and unstable gait pattern is observed in a number of patients. In many cases, one leg can move in a relatively normal pattern, while the other leg is dysfunctional due to paralysis. We have adopted the so-called assist-as-needed control that encourages the patient to walk as much as possible while the robot assists as necessary to create the gait motion of the paralyzed leg. A virtual wall was implemented for the assist-as-needed control. A position based admittance controller was applied in the swing phase to follow human intentions for both the normal and paralyzed legs. A position controller was applied in the stance phase for both legs. A power controller was applied to obtain stable performance in that the output power of the system was delimited during the sample interval. In order to verify the proposed control algorithm, we performed a simulation with 1-DOF leg models. The preliminary results have shown that the control algorithm can follow human intentions during the swing phase by providing as much assistance as needed. In addition, the virtual wall effectively guided the paralyzed leg with stable force display.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.830-839
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• 1993

Agricultural hydraulic robot which was reported in Part Ⅰ had been developed . The robot satisfied performance to intend before development. For actual use, however, it have been necessary to reduce manipulator weigh and to simplify construction of hydraulic control valve. Then, working stress of manipulator link and pressure fluctuation of hydraulic circuit were measured. Step and frequency response tests were done subject to amplitude of reference voltage of 0.1 , 0.3 , 0.5 and 1.0v. and delivery pressure of 3.5 and 5.0MPa. Working stress were about 25% comparing with fatigue strength, Thus, mass of manipulator might be reduce to 30 %. In hydraulic control system, virtual natural frequency of 6.5Hz is produced from the combination of drain passage area shortage of servovalve. Further , because of passage area shortage , working pressure at both side of cylinder was acted on. This phenomenon prevent utilize effectively engine power. Then, control valve for new model was p oposed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.74-79
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• 2005

In this paper, we propose a novel approach to decentralized motion planning and conflict-resolution for multiple mobile agents working in an environment with unexpected moving obstacles. Our proposed motion planner has two characteristics. One is a real-time collision prognosis based on modified collision map. Collision map is a famous centralized motion planner with low computation load, and the collision prognosis hands over these characteristics. And the collision prognosis is based on current robots status, maximum robot speeds, maximum robot accelerations, and path information produced from off-line path planning procedure, so it is applicable to motion planner for multiple agents in a dynamic environment. The other characteristic is that motion controller architecture is based on potential field method, which is capable of integrating robot guidance to the goals with collision avoidance. For the architecture, we define virtual obstacles making delay time for collision avoidance from the real-time collision prognosis. Finally the results obtained from realistic simulation of a multi-robot environment with unknown moving obstacles demonstrate safety and efficiency of the proposed method.

• 한국CDE학회논문집
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• 제17권1호
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• pp.35-44
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• 2012

Many automobile manufacturers are doing experiment on manufacturing environments by using an augmented reality technology. However, system layout and process simulation by using the virtual reality technology have been performed actively more than by using the augmented reality technology in practical use so far. Existing automobile assembly by using the augmented reality requires the precise calibrating work after setting the robot because the existing augmented reality system for the automobile assembly system configuration does not include the end tip deflection and the robot joints deflection due to the heavy weight of product and gripper. Because the robot is used mostly at the automobile assembly, the deflection problem of the robot joint and the product in the existing augmented reality system need to be improved. Moreover camera lens calibration has to be performed precisely to use augmented reality. In order to improve this problem, this paper introduces a method of the software based calibration to apply the augmented reality effectively to the automobile assembly system. On the other hand, the camera lens calibration module and the direct compensation module of the virtual object displacement for the augmented reality were designed and implemented. Furthermore, the developed automobile assembly system oriented AR-system was verified by the practical test.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집(한일합동학술편); 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.915-920
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• 1987

When a task requires two robot arms to move in a cooperative manner sharing a common workspace, potential collision exists between the two robot arm . In this paper, a novel approach for collision-free trajectory planning along paths of two SCARA-type robot arms is presented. Specifically, in order to describe potential collision between the links of two moving robot arms along the designated paths, an explicit form of "Virtual Obstacle" is adopted, according to which links of one robot arm are made to grow while the other robot arm is forced to shrink as a point on the path. Then, a notion of "Coordination Chart" is introduced to visualize the collision-free relationship of two trajectories.of two trajectories.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.540-540
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• 2000

This paper explores design and control methods of a surgical robot for total hip replacement surgery which can be easily maneuvered by a surgeon Like an advanced surgical tool. The 3-DOF in-parallel surgical robot is fixed directly onto patient's femur by the bone clamp during surgery. With the master/slave combined surgical robot, the surgeon can directly control the motion of the surgical robot with surgeon's experience and judgment during operation. For the easiness of operation, the master/slave combined robot is controlled using admittance control paradigm. And for the precise operation, the robot motion is restricted at the surgical boundary using virtual hard wall display.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.507-510
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• 1997

In this paper, we proposed force reflection method using joystick or controlling rehabilitation assisting mobile robot. We defined reflected orce equation as two terms. One is distance between mobile robot and obstacle, the other is speed of rehabilitation assisting robot. And we found the each gain value which guarantees stable navigation of robot. And we experimented simulation with simulation program supporting virtual 2-D map. Through the experiments, we confirmed force reflection algorithm is efficient when controlling rehabilitation assisting robot.

• 한국콘텐츠학회논문지
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• 제18권7호
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• pp.322-329
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• 2018

원격제어는 명령을 전달하는 마스터 장치와 원격지에 위치한 로봇을 슬레이브로 간주하는 방식이다. 이러한 원격제어의 경우, 양 에이전트 간의 동특성, 전송속도 차이에 의해 가상환경을 이용한 가상 슬레이브를 통해 조작자가 원격제어의 특수성을 선행 수행하는 것이 일반적이다. 기존의 가상 슬레이브는 연산량의 한계에 의해 동역학적 효과를 제거한 그래픽 모델로 구성하는 것이 일반적이나 이는 원격지 로봇의 동특성이 무시되어 실제 원격제어시의 실재감을 살리기 어렵다. 본 논문에서는 로봇의 정동역학 모델을 이용하여 이를 원격제어에 활용하고, 가상 환경에서 상대적으로 느린 제어 주기에 의해 발생하는 정동역학의 수치오류를 보완하는 보상 기법을 제안하고 이를 실제 환경과의 원격제어와 비교하고자 한다.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2001년도 추계학술발표논문집
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• pp.260-264
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• 2001

This paper presents virtual reality using 6-DOF Haptic interface. It is proposed reappearance of force using 6-DOF Haptic device that was designed by previous studies and 3D image considered time delay. The performance of conventional control is excellent in the case of the exactly known dynamic model of the robot, but degrades seriously as the uncertainty of the model increases. The virtual reality using 6-DOF Haptic interface is presented here to overcome such that, and verified through the experiment.