• Journal of the Optical Society of Korea
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• v.19 no.4
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• pp.421-426
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• 2015

This paper presents a hybrid single optical system for an LED surgical light that combines the advantages of both lens- and reflector-type single optical systems. The proposed hybrid single optical system includes a lens in the center and the LED light originating from the lens is redirected using a reflector to achieve a high beam spread. Iterative optical software simulations are used to provide data for the design of the lens and reflector for a single optical system, and for a complex optical system for the LED light assembly. The resulting data is also used to fabricate a prototype system. Experiments using the prototype of the hybrid single optical system and a mock-up LED surgical light confirm the system's shadow dilution performance and its applicability to surgical operations.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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• pp.61-66
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• 2020

For simple and repetitive transport tasks in limited spaces such as in factories, it is more efficient to use mobile robots instead of human workers. For this reason, the reliance on mobile robots is increasing due to the increased implementation of smart factories. Currently, the structural design of the Mecanum wheel is required to ensure the stability of the moving robot since it is used for the transport of not only small products but also large products. In this paper, to improve the stability and durability of the Mecanum wheel, ways to improve the structure of the Mecanum wheel are presented. Then, using the Castigliano theorem, the structural stability is reviewed through the deflection on existing and improved structures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1429-1432
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• 2005

This work is towards the development of a low-cost, small-sized inertial navigation system(INS) which consists of 3 accelerometers, 3 semiconductor gyros and a magnetic compass sensor. This paper explains in detail the structure of the developed system and proposes a 3 dimensional attitude estimation algorithm with Indirect Kalman Filter. The experiments are performed with the developed system attached to a 6 DOF robot for showing the effectiveness of the algorithm.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.399-402
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• 2017

텍스트 기반 언어 스몰베이직은 적은 수의 언어 특징을 가지고 있어 배우기 쉽고 이후에 C/C++/Java로 빠르게 전환할 수 있기 때문에 청소년 코딩 교육용 언어로 적합하다. 코딩 교육에 흥미를 높이기 위해 다양한 라이브러리가 필요한데 마이크로소프트에서 개발한 스몰베이직 환경에서는 로봇 프로그래밍을 위한 라이브러리를 지원하지 않는다. 이 논문에서 오픈소스 소프트웨어 스몰베이직 환경하에 동작하는 햄스터 로봇 라이브러리를 설계 및 구현하였다. 교육용 언어 스크래치와 파이썬에서 유사한 로봇 프로그래밍 라이브러리를 지원하지만 스크래치는 그림 기반 언어이기 때문에 이후 C/C++/Java로 전환하기 어렵고, 파이썬은 객체와 클래스 개념을 포함하고 잇어서 초보자가 배우기 어렵다. 이 논문에서 개발한 라이브러리를 활용하여 데모 프로그램을 작성함으로써 쉽게 스몰베이직 기반 로봇 프로그래밍을 할 수 있을을 확인하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1074-1079
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• 2007

We will introduce speech/speaker recognition algorithm for the isolated word. In general case of speaker verification, Gaussian Mixture Model (GMM) is used to model the feature vectors of reference speech signals. On the other hand, Dynamic Time Warping (DTW) based template matching technique was proposed for the isolated word recognition in several years ago. We combine these two different concepts in a single method and then implement in a real time speaker/speech recognition system. Using our proposed method, it is guaranteed that a small number of reference speeches (5 or 6 times training) are enough to make reference model to satisfy 90% of recognition performance.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.318-325
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• 2010

This paper proposes a new string controller for puppet which is optimized in terms of the number of motors and its size. To optimize the number of motors needed for generating the essential motions of puppet, the motion of bending a leg is implemented by one string and the walking motion by two legs is implemented by one motor. To minimize the space needed for the controller when generating the essential motions of puppet, cylindrical and articulated joints are used in the controller. The proposed controller is actually implemented to perform various puppet shows and it has been proved that the size of the controller is small enough for two puppets to stand close to shake hands and it is fast enough to simulate fast dance motions.

• The Journal of Korea Robotics Society
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• v.15 no.2
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• pp.131-138
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• 2020

This paper proposes a low-cost robotic surgery system composed of a general purpose robotic arm, an interface for daVinci surgical robot tools and a modular haptic controller utilizing smart actuators. The 7 degree of freedom (DOF) haptic controller is suspended in the air using the gravity compensation, and the 3D position and orientation of the controller endpoint is calculated from the joint readings and the forward kinematics of the haptic controller. Then the joint angles for a general purpose robotic arm is calculated using the analytic inverse kinematics so that that the tooltip reaches the target position through a small incision. Finally, the surgical tool wrist joints angles are calculated to make the tooltip correctly face the desired orientation. The suggested system is implemented and validated using the physical UR5e robotic arm.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1090-1093
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• 1987

In this paper, we describe the principle, the procedure and calculation of the measurement. Finally the experimental results are shown and discussions are given. Interpreting of a skewed symmetry in the image as a real symmetry in the 3-D space provides strong constraints on 3-D sharp analysis. In order to apply the idea to the real scene, a method is presented which can find the skewed symmetry in the image of the skewed symmetrical object, even if it is occluded partly. there parameters of the skewed symmetry are estimated by examining peaks in two 2-D hough spaces, onto which the parameters of all candidates of boundary line segments for skewed symmetries are voted. The method is characterized with a small amount of computation, finding of multiple symmetry axes and inference of the occluded parts of the symmetrical object.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.179-180
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• 2012

풍력 발전기는 과 풍속 시 전기적이나 기계적인 안전을 고려해 날개의 회전수를 줄이거나 정지하도록 제어된다. 소형풍력발전기는 스위치로 출력을 단락시켜 발전기를 정지시키며, 이때 큰 단락 전류로 인해 발전기 코일 또는 정류기 소손 등의 고장이 발생될 수 있다. 따라서 본 논문에서는 여러 개의 저항을 선택적으로 발전기 출력에 연결하도록 제어하는 방법을 제안하여 발전기가 안전하게 정지되게 하고, 200W 풍력 발전기를 대상으로 제안된 방법을 적용하여 과 풍속 환경에서 실험한 결과 발전기의 안정적인 제동을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.299-301
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• 1996

Since a standard lens has small sight angle, a fish-eye lens can be used in order to obtain wide sight angle for the robot vision system. In spite of the advantage, the image through the lens has variable resolution; the central information of the lens is of high resolution, but the peripheral information is of low resolution. Owing to this difference of resolution, the variable resolution image should be transformed to a uniform resolution image in order to determine the positions of the objects in the image. In this work, the correction method for the distorted image is presented and the performance is analyzed. Furthermore, the camera with a fish eye lens can be used to determine the real world coordinates. The performance is shown through experiments.