• 한국인터넷방송통신학회논문지
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• 제10권4호
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• pp.77-82
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• 2010

본 연구에서는 가상낚시시스템(VFS, Virtual Fishing System)을 위해 제작된 햅틱장치인 FishBot을 개발한다. FishBot는 XY테이블에 휠축을 장착한 3자유도 로봇으로 구성된다. 물고기의 동작을 모사하기 위해 XY 축 제어는 토크값을 가변적으로 제한하는 모션 위치 제어 모드로 하고 휠 축은 힘제어 모드로 하였다. 낚싯대는 실제 낚싯대에 LED를 장착하고 웹 카메라를 튜닝하여 낚싯대의 위치를 인식할 수 있도록 하였다. 결과적으로 제작된 Fishbot은 물고기와 같이 위치와 속도를 변화하고 DAC를 통해 낚는 힘을 제어할 수 있으며 낚싯대 끝단의 위치를 관측하여 가상현실시스템(Virtual Reality System)상에서 연동할 수 있게 하였다.

• 제어로봇시스템학회논문지
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• 제3권3호
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• pp.297-304
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• 1997

In stereo vision, camera modeling is very important because the accuracy of the three dimensional locations depends considerably on it. In the existing stereo camera models, two camera planes are located in the same plane or on the optical axis. These camera models cannot be used in the active vision system where it is necessary to obtain two stereo images simultaneously. In this paper, we propose four kinds of stereo camera models for active stereo vision system where focal lengths of the two cameras are different and each camera is able to rotate independently. A single closed form solution is obtained for all models. The influence of the stereo camera model to the field of view, occlusion, and search area used for matching is shown in this paper. And errors due to inaccurate focal length are analyzed and simulation results are shown. It is expected that the three dimensional locations of objects are determined in real time by applying proposed stereo camera models to the active stereo vision system, such as a mobile robot.

• 로봇학회논문지
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• 제17권3호
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• pp.339-346
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• 2022

To operate in real environment, humanoid robots should be able to react to unknown disturbances. To deal with disturbances, various robust control algorithms have been developed for decades. But for collaborative works such as teleoperation system, a compliance control can be the better solution for disturbance reactions. In this paper, a center of mass (CoM) compliance control algorithm for humanoid robots is proposed. The proposed algorithm is based on the state observer and positive feedback of disturbance. With the state observer based on humanoid CoM control performance model, disturbance in each direction can be observed. The positive feedback of disturbances to the reference CoM trajectory enables compliant motion. The main contributions of this algorithm are achieving compliance independently in each axis and maintaining balance against external force. Through dynamic simulations, the performance of the proposed method was demonstrated. Under two types of disturbance conditions, humanoid robot DYROS-JET reacted with compliant motion via the proposed algorithm.

• 한국산학기술학회논문지
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• 제21권3호
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• pp.246-252
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• 2020

국내외적으로 케이블지지 교량에서 케이블의 착설 및 잔설 등이 낙설됨에 따라 안전사고가 발생하고 있다. 낙설에 의한 직접적인 피해뿐만 아니라 교통사고 등 추가적인 2차 피해가 발생하고 있어, 이에 대한 대책 마련이 필요하다. 이를 예방하기 위한 다양한 방안들이 제시되고 있지만, 안전성과 실용성에서는 여전히 문제점을 가지고 있다. 본 연구에서는 기존 방법 중 능동적인 잔설 제거 방법 중 하나인 케이블 로봇을 활용하고자 하였고, 잔설 제거의 효율을 높이기 위하여 로봇의 등반 능력을 높이는 다양한 방법이 적용되었다. 교량 케이블의 다양한 직경에 적용할 수 있도록 로봇의 가용 범위를 유동적으로 조절할 수 있게 하였다. 또한, 케이블 잔설 제거 로봇의 활용성을 높이기 위하여 케이블의 표면 상태를 실시간으로 점검할 수 있도록 고해상도 카메라를 설치하고, 장력 측정을 위하여 3축 가속도계와 장력 변환 알고리즘을 추가하여 잔설제거 뿐만 아니라 겨울철 이외에도 케이블 점검 로봇으로 활용될 수 있도록 개발하였다. 성능 검증을 위하여 실내 및 현장 실험을 수행하였고, 향후 점검 로봇에 대한 개선사항에서 대해서도 제안 하였다.

• 한국시뮬레이션학회논문지
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• 제9권1호
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• pp.39-54
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• 2000

Presented in this paper is a modeling and simulation methodology for 3 dimensional man-made systems. Based on DEVS(discrete event system specification) formalism[13], we propose GK-DEVS (geometrical and kinematic DEVS) formalism to describe the geometrical and kinematic structure and continuous state dynamics. To represent geometry and kinematics, we add a hierarchical structure to the conventional atomic model. In addition, we employ the "empty event" and its external event function for continuous state changing. In terms of abstract simulation algorithm[13], the simulation method of GK-DEVS, named GK-Simulator, is proposed for combined discrete-continuous simulation. Using GK-DEVS, the simulation of an FMS(flexible manufacturing system) consisting of a luring machine, a 3-axis machine and a RGV-mounted robot has been peformed.en peformed.

• 전력전자학회논문지
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• 제19권2호
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• pp.149-156
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• 2014

This paper proposes the battery charging algorithm for small-scale wind power generator using three phase PWM converter. it is impossible to control output power of the converter in over wind speed region since back EMF of PMSG is higer than battery voltage. Therefore, battery charging algorithm is proposed to expand battery charging over wind speed region. The suggested method is using the q-axis current for battery charging in the rated wind speed region. In the over wind speed region after it lower back EMF of PMSG using d-axis current it can control output power of the converter. The validity of the proposed algorithm are verified by experiments.

• 제어로봇시스템학회논문지
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• 제17권2호
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• pp.176-182
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• 2011

Industrial network, often referred to as fieldbus, becomes an indispensable component for intelligent manufacturing systems. Thus, in order to satisfy the real-time requirements of field devices such as sensors, actuators, and controllers, numerous fieldbus protocols have been developed. But, the application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multi-vendor products. As an alternative to fieldbus, the Ethernet (IEEE 802.3) technology is being adapted to the industrial environment. However, the crucial technical obstacle of Ethernet is its non-deterministic behavior that cannot satisfy the real-time requirements. Recently, the EtherCAT protocol becomes a very promising alternative for real-time industrial application due to the elimination of uncertainties in Ethernet. This paper focuses on the implementation of the IEC 61800 based real-time EtherCAT network for multi-axis smart driver. To demonstrate the feasibility of the implemented EtherCAT slave module, its synchronization performance is evaluated on the experimental EtherCAT testbed with a single axis smart driver.

• 한국기계가공학회지
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• 제21권3호
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• pp.92-99
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• 2022

Owing to the excellent corrosion resistance of titanium alloys, they are widely used as materials for aircraft components. However, in terms of machining, dimensional deformation methods vary significantly, such as forging, owing to their difficult-to-cut property and the uncontrollable vibration generated during machining. A method to minimize the vibration generated during machining by applying advanced tools and controlling the sequence of machining processes, which can improve the machinability and precision of titanium alloy-forged low-angle components, is proposed herein. Using the proposed tool and based on a process order experiment, the efficiency of the machining process is verified by measuring the dimensional deformation of the low-angle component.

• International Journal of Control, Automation, and Systems
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• 제4권2호
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• pp.227-235
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• 2006

For a sophisticated humanoid that explores and learns its environment and interacts with humans, anthropomorphic physical behavior is much desired. The human vision system orients each eye with three-degree-of-freedom (3-DOF) in the directions of horizontal, vertical and torsional axes. Thus, in order to accurately replicate human vision system, it is imperative to have a simulator with 3-DOF end-effector. We present a 3-DOF anthropomorphic oculomotor system that reproduces realistic human eye movements for human-sized humanoid applications. The parallel link architecture of the oculomotor system is sized and designed to match the performance capabilities of the human vision. In this paper, a biologically-inspired mechanical design and the structural kinematics of the prototype are described in detail. The motility of the prototype in each axis of rotation was replicated through computer simulation, while performance tests comparable to human eye movements were recorded.

• 한국정밀공학회지
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• 제26권2호
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• pp.35-44
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• 2009

Long stroke Fast Tool Servo (LFTS) with maximum stroke of $432{\mu}m$ is designed, manufactured and tested for fabrication of optical free-form surfaces. The large amount of stroke in LFTS has been realized by utilizing the hinge and lever mechanisms which enable the displacement amplification ratio of 4.3. In this mechanism the peculiar shape was devised for maximizing the displacement of end tip in LFTS and special mechanical spring has been mounted to provide the sufficient preload to the piezoelectric actuator. Also, its longitudinal motion of tool tip can be measured by capacitive type displacement sensor and closed-loop controlled to overcome the nonlinear hysteresis. In order to verify the static and dynamic characteristics of designed LFTS, several features including step response, frequency response and cut-off frequency in closed-loop mode were experimentally examined. Also, basic machining result shows that the proposed LFTS is capable of generating the optical free-form surface as an additional axis in diamond turning machine.