• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1433-1440
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• 2016

• 제어로봇시스템학회논문지
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• 제21권4호
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• pp.356-360
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• 2015

In this paper, we design and implement a mobile robot with variable structure for tip-over prevention. The mobile robot is designed for the purpose of stable drive and work in outdoor terrain. The outdoor terrain is rough and uneven. In this terrain, the tip-over of the mobile robot can occur while driving and working. Therefore, the structure of the mobile robot must be designed in consideration of stable drive and work. The proposed structure is defined as an X-shape for overall balance of the mobile robot. The shape is designed by using a multi-level structure for reducing the size of the robot. To verify the effectiveness of the proposed design, we analyze the tip-over characteristics according to the height of gravitational center and the extension length of the robot. Finally, we develop a prototype of the mobile robot with variable structure, taking the results of the tip-over analysis into consideration.

• Wind and Structures
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• 제30권6호
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• pp.547-558
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• 2020

With the development of economy and construction technology, more and more bridges are built in complex mountainous areas. Accurate assessment of wind parameters is important in bridge construction at complex terrain. In order to investigate the wind characteristics in the high-altitude difference area, a complex mountain terrain model with the scale of 1:2000 was built. By using the method of wind tunnel tests, the study of wind characteristics including mean wind characteristics and turbulence characteristics was carried out. The results show: The wind direction is affected significant by the topography, the dominant wind direction is usually parallel to the river. Due to the sheltering effect of the mountain near the bridge, the wind speed and wind attack angle along the bridge are both uneven which is different from that at flat terrain. In addition, different from flat terrain, the wind attack angle is mostly negative. The wind profiles obey exponential law and logarithmic law. And the fitting coefficient is consistent with the code which means that it is feasible to use the method of wind tunnel test to simulate complex terrain. As for turbulence characteristics, the turbulence intensity is also related to the topography. Increases sheltering effect of mountain increases the degree of breaking up the large-scale vortices, thereby increasing the turbulence intensity. Also, the value of turbulence intensity ratio is different from the recommended values in the code. The conclusions of this study can provide basis for further wind resistance design of the bridge.

• 한국지능시스템학회논문지
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• 제21권6호
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• pp.692-697
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• 2011

로봇의 이동성 향상을 위해 다양한 환경에 적응할 수 있는 로봇의 연구 개발이 활발하게 진행되고 있다. 본 논문에서는 휠(wheel)과 다리(Leg)기반 변형이 가능하고, 로봇간 상호 결합이 가능한 복합 이동형 로봇을 제안하였다. 복합 이동형 로봇은 로봇간 결합을 위해 페그 모듈과 컵 모듈을 로봇의 전면과 후면에 각각 장착하고, 주행과 보행이 가능하도록 구현하였다. 다양한 지형에서 이동성을 향상을 위해 임베디드 영상기반 결합 및 분리 알고리즘을 제안하였으며, 로봇간 결합을 통해 끊어진 도로와 비평탄 지형에서의 결합 이동 방법을 제안하였다. 제안한 방법은 로봇의 전면과 밑면에 장착된 PSD 센서를 이용하여 지형을 인식하고, 지형에 맞은 극복 알고리즘을 통해 로봇간 협력을 통해 이동성을 향상시킨다. 제안한 방법들은 임베디드시스템 기반의 복합 주행 이동형 로봇을 실제 제작하여 실험 통해 성능을 검증하였다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2007년도 추계 종합학술대회 논문집
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• pp.942-946
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• 2007

최근 새로운 지구중력장 모델의 개발로 인하여 중력관련 응용분야의 향상된 연구결과가 기대되고 있다. 본 연구는 지구중력장 모형으로부터 남한지역에 대한 고도이상(height anomalies)를 산정하고 지형보정 여부에 따른 지역별 지오이드고의 특성을 분석하여 국내 지오이드고 개발연구에 기여하고자 한다. 이를 위하여 다양한 중력 관측 자료를 조합한 5가지 지구중력장모형과 지형보정을 위한 ETOPO2모형을 선정하고 남한지역의 경 위도 $1^{\circ}{\times}1^{\circ}$ 6개 육상부 및 4개 해상부에 대한 30"격자의 지오이드고를 산정한 후, 국립해양조사원의 NORI-05모델에 의한 결과와 비교하였다. 육상부의 경우, GPS 관측이 수행된 수준점 50측점 및 삼각점 30측점을 점검점으로 선정하여 GPS/Leveling, NORI-05 및 5가지 지구중력장모형에 의한 지오이드고를 비교 분석하였다. 연구결과, EIGEN-CG03C 및 EIGEN-CG04C 중력장모형이 GPS/Leveling 결과에 근접함을 보였고 국내 정밀 지오이드고를 산정할 경우, 육상 및 해상에서 지형의 요철이 심한 지역일수록 정밀한 지형보정의 필요성을 확인할 수 있었다.

• 한국기계가공학회지
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• 제19권4호
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• pp.85-92
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• 2020

Applications for the unmanned aerial vehicle (UAV) have expanded enormously in recent years. Of all its various technologies, the UAV's ability to take off and land in a moving environment is particularly required for military or oceanic usage. In this study, we develop a novel leveling platform that allows the UAV to stably take off and land even on uneven terrains or in moving environments. The leveling platform is composed of an upper pad and a lower mobile base. The upper pad, from which the UAV can take off or land, is designed in the form of a 2 degrees of freedom (DOF) gimbal mechanism that generates the leveling function. The lower mobile base has a four-wheel drive structure that can be operated remotely. We evaluate the developed leveling platform by performing extensive experiments on both the horizontal terrain and the 5-degree ramped terrain, and confirm that the leveling platform successfully maintains the horizontal pose on both terrains. This allows the UAV to stably take off and land in moving environments.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.228-231
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• 2003

This paper presents the leg trajectory generation for the quadruped robot with genetic-fuzzy algorithm. To have the nobility even at uneven terrain, a robot is able to recognize obstacles, and generates moving path of body that can avoid obstacles. This robot should have its own avoidance algorithm against obstacles, forwarding to target without collision. During walking period, n robot recognizes obstacle from external environment with a PSD and some interface, and this obstacle information is converted into proper the body rotation angle by fuzzy inference engine. After this process, we can infer the walking direction and walking distance of body, and finally can generate the optimal Beg trajectory using genetic algorithm. All these methods are verified with PC simulation program, and implemented to SERO-V robot.

• 로봇학회논문지
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• 제5권4호
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• pp.367-376
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• 2010

This Paper Proposes A Robust Image Stabilization System For A Mobile Robot Using An Extended Kalman Filter (Ekf). Though Image Information Is One Of The Most Efficient Data Used For Robot Navigation, It Is Subjected To Noise Which Is The Result Of Internal Vibration As Well As External Factors Such As Uneven Terrain, Stairs, Or Marshy Surfaces. The Camera Vibration Deteriorates The Image Resolution By Destroying The Image Sharpness, Which Seriously Prevents Mobile Robots From Recognizing Their Environment For Navigation. In This Paper, An Inclinometer Was Used To Measure The Vibration Angle Of The Camera System Mounted On The Robot To Obtain A Reliable Image By Compensating For The Angle Of The Camera Vibration. In Addition The Angle Prediction Obtained By Using The Ekf Enhances The Image Response Analysis For Real Time Performance. The Experimental Results Show The Effectiveness Of The Proposed System Used To Compensate For The Blurring Of The Images.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권3호
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• pp.131-140
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• 2005

Fault-tolerant gait generation of a hexapod robot with crab walking is proposed. The considered fault is a locked joint failure, which prevents a joint of a leg from moving and makes it locked in a known position. Due to the reduced workspace of a failed leg, fault-tolerant crab walking has a limitation in the range of heading direction. In this paper, an accessible range of the crab angle is derived for a given configuration of the failed leg and, based on the principles of fault-tolerant gait planning, periodic crab gaits are proposed in which a hexapod robot realizes crab walking after a locked joint failure, having a reasonable stride length and stability margin. The proposed crab walking is then applied to path planning on uneven terrain with positive obstacles. i.e., protruded obstacles which legged robots cannot cross over but have to take a roundabout route to avoid. The robot trajectory should be generated such that the crab angle does not exceed the restricted range caused by a locked joint failure.

• International Journal of Control, Automation, and Systems
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• 제6권4호
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• pp.551-558
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• 2008

This paper deals with the real-time stable walking for a humanoid robot, ISHURO-II, on uneven terrain. A humanoid robot necessitates achieving posture stabilization since it has basic problems such as structural instability. In this paper, a stabilization algorithm is proposed using the ground reaction forces, which are measured using FSR (Force Sensing Resistor) sensors during walking, and the ground conditions are estimated from these data. From this information the robot selects the proper motion pattern and overcomes ground irregularities effectively. In order to generate the proper reaction under the various ground situations, a fuzzy algorithm is applied in finding the proper angle of the joint. The performance of the proposed algorithm is verified by simulation and walking experiments on a 24-DOFs humanoid robot, ISHURO-II.