• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.162-162
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• 2000

We describe a new optical-type guide sensor for AGV. It is robust the disturbance of the light. The developed optical-type guide sensor is very useful in the clean room environment where the light disturbance is very critical through the hole on the surface of the floor.

• Current Optics and Photonics
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• v.5 no.3
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• pp.298-305
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• 2021

Modern distance sensing methods employ various measurement principles, including triangulation, time-of-flight, confocal, interferometric and frequency comb. Among them, the triangulation method, with a laser light source and an image sensor, is widely used in low-cost applications. We developed an omnidirectional two-dimensional (2D) distance sensor based on the triangulation principle for indoor floor mapping applications. The sensor has a range of 150-1500 mm with a relative resolution better than 4% over the range and 1% at 1 meter distance. It rotationally scans a compact one-dimensional (1D) distance sensor, composed of a near infrared (NIR) laser diode, a folding mirror, an imaging lens, and an image detector. We designed the sensor layout and configuration to satisfy the required measurement range and resolution, selecting easily available components in a special effort to reduce cost. We built a prototype and tested it with seven representative indoor wall specimens (white wallpaper, gray wallpaper, black wallpaper, furniture wood, black leather, brown leather, and white plastic) in a typical indoor illuminated condition, 200 lux, on a floor under ceiling mounted fluorescent lamps. We confirmed the proposed sensor provided reliable distance reading of all the specimens over the required measurement range (150-1500 mm) with a measurement resolution of 4% overall and 1% at 1 meter, regardless of illumination conditions.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.199-202
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• 2007

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication, ocean observation and meteorological observation. Conventional thermal control design, using MLI (Multi Layer Insulation), OSR (Optical Solar Reflector), heater and heat pipe, is utilized. Ka-band components are installed on South wall, while other equipment for sensors are installed on the opposite side, North wall. High dissipating communication units are located on external (surface) heat pipe and are covered by internal insulation blankets to decouple them from the rest of the satellite. External satellite walls are covered by MLI or OSR for insulation from space and for rejection internal heat to space. The ocean and meteorological sensors are installed on optical benches on the top floor to decouple thermally from the satellite. Single solar array wing is adopted in order to secure clear field of view of radiant cooler of IR meteorological sensor. This paper presents principles of thermal control design for the COMS.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.55-61
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• 2020

Getting on and off an elevator is one of the most important parts for multi-floor navigation of a mobile robot. In this study, we proposed the method for the pose recognition of elevator doors, safe path planning, and motion estimation of a robot using RGB-D sensors in order to safely get on and off the elevator. The accurate pose of the elevator doors is recognized using a particle filter algorithm. After the elevator door is open, the robot builds an occupancy grid map including the internal environments of the elevator to generate a safe path. The safe path prevents collision with obstacles in the elevator. While the robot gets on and off the elevator, the robot uses the optical flow algorithm of the floor image to detect the state that the robot cannot move due to an elevator door sill. The experimental results in various experiments show that the proposed method enables the robot to get on and off the elevator safely.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.6
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• pp.601-608
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• 2011

This paper presents the damage assessment of a building structure by using a novel optical fiber accelerometer system. Especially, a sub-scaled building model is designed and manufactured to check up the feasibility of the optical fiber accelerometer for structural health monitoring. The novel accelerometer exploits the moir$\acute{e}$ fringe optical phenomenon and two pairs of optical fibers to measure the displacement with a high accuracy, and furthermore a pendulum to convert the displacement into acceleration. A prototype of optical fiber accelerometer system has been successfully developed that consists of a sensor head, a control unit and a signal processing unit. The building model is also designed as a 4-story building with a rectangular shape of $200{\times}300$ mm of edges. Each floor is connected to the next ones by 6 steel columns which are threaded rods. Basically, a random vibration test of the building model is done with a shaker and all of acceleration data is successfully measured at the assigned points by the optical fiber accelerometer. The experiments are repeated in the undamaged state and the damaged state. The comparison of dynamic parameters including the natural frequencies and the eigenvectors is successfully carried out. Finally, the optical fiber accelerometer is proven to be prospective to evaluate dynamic characteristics of a building structure for the damage assessment.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.1
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• pp.54-61
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• 2012

In this paper, the pose estimation method for the satellite GTB (Ground Test Bed) using vision/MEMS IMU (Inertial Measurement Unit) integrated system is presented. The GTB for verifying a satellite system on the ground is similar to the mobile robot having thrusters and a reaction wheel as actuators and floating on the floor by compressed air. The EKF (Extended Kalman Filter) is also used for fusion of MEMS IMU and vision system that consists of a single camera and infrared LEDs that is ceiling landmarks. The fusion filter generally utilizes the position of feature points from the image as measurement. However, this method can cause position error due to the bias of MEMS IMU when the camera image is not obtained if the bias is not properly estimated through the filter. Therefore, it is proposed that the fusion method which uses the position of feature points and the velocity of the camera determined from optical flow of feature points. It is verified by experiments that the performance of the proposed method is robust to the bias of IMU compared to the method that uses only the position of feature points.

• Journal of the Korea Society of Computer and Information
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• v.26 no.5
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• pp.9-16
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• 2021

In this paper, we propose a building exploration drone that can be used for a digital twin-based building control system. The existing building control system using a fixed position sensor box has a problem that a management blind spot occurs. And because people patrol themselves, it takes a lot of human resources. In this paper, a drone equipped with a temperature and humidity sensor and a gas leak detection sensor is used to search the internal path of the building centering on the control blind spot. It also aims to solve the problem of the building control system by transmitting information in real time along with the video. In addition, it has a stable hovering function using an optical floor sensor and can be applied to an existing digital twin-based building control system. The results of this study are believed to be of great help in improving the quality of digital twin control systems using drones.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.01a
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• pp.185-186
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• 2021

기존의 건물 점검은 사람이 직접 들어가 확인하는 방식이 일반적이다. 본 연구에서는 건물 탐사를 보다 안전하고 신속하게 하는 것을 전제로 하여 현재 상용화 되고 있는 드론과 아두이노를 이용한 센서를 적용하고자 한다. 건물 점검은 사람이 직접 들어가 확인하는 만큼 안전 수칙을 지켜가며 실시해야 하지만, 불편함이나 귀찮음을 핑계로 지켜지지 않는 경우가 대다수이다. 지켜지지 못한 안전 수칙에 더불어, 건물의 직접적인 상태를 미리 알지 못하고 진입하게 됨으로 발생하는 인명피해는 불가피하다. 본 논문은 이러한 문제점들을 개선하기 위해 기존의 어려운 조작의 드론에 호버링이 가능하게 하는 옵티컬 플로어 센서를 장착하여 조작을 보다 쉽게 하고 아두이노의 센서를 적용한 '건물 탐사 드론' 기술을 제안한다. 기존의 드론과 다르게 카메라와 센서를 이용해 건물의 점검을 대신하고, 센서들의 값을 앱으로 전송받아 핸드폰으로 받아 볼 수 있다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.487-488
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• 2021

시설물 점검은 사람이 직접 들어가거나 올라가 확인하는 방식이 일반적이다. 본 연구에서는 시설물 점검을 보다 안전하고 신속하게 하는 것을 전제로 하여 현재 상용화 되고 있는 드론과 아두이노를 이용한 센서를 적용하고자 한다. 본 논문은 기존의 어려운 조작의 드론에 건물 내부에서 호버링이 가능하게 하는 옵티컬 플로어 센서를 장착아여 조작을 보다 쉽게 한다. 또한, 외부 비행 시 GPS센서를 사용하여 좌표지정을 통한 자동비행을 가능하게 하고 아두이노의 센서와 펌프를 적용한 "오토파일럿이 가능한 시설물 관리 드론" 기술을 제안한다. 기존의 드론과 다르게 카메라와 센서를 이용해 시설물 관리를 대신하고, 외부 시설물 관리나 농업 등에서 사용할 때 좌표를 지정해 사용자가 직접 조작하지 않아도 지정한 좌표로 드론이 이동하여 관리 및 임무를 수행한다. 센서들의 값을 앱으로 전송받아 핸드폰으로 받아 볼 수 있다.