거리측정이 가능한 단동형 수중 스테레오 카메라의 제어

이판묵(PAN-MOOK LEE),전봉환(BONG-HWAN JEON),이종무(CHONG-MOO LEE) 한국해양공학회 2001 韓國海洋工學會誌 Vol.15 No.1

This paper presents the control of the image disparity of a parallel stereo camera and its application to an underwater stereo camera to enhance the working efficiency of underwater vehicles that are equiped with manipulators in seabed operation. The stereo camera consists of two parallel lenses mounted on a lateral moving base and two CCD cameras mounted on a longitudinal moving base, which is embedded in a small pressure canister for underwater application. Because the lateral shift is related to the backward shift with a nonlinear relation, only one control input is needed to control the vergence and focus of the camera with a special driving device. We can get clear stereo vision with the camera for all the range of objects in air and in water, especially in short range objects. The control system of the camera is so simple that we are able to realize a small stereo camera system and apply it to a stereo vision system for underwater vehicles. This paper also shows how to acquire the distance information of an underwater object with this stereo camera. Whenever we focus on an underwater object with the camera, we can obtain three-dimensional images and distance information in real-time.

심해무인잠수정 해미래를 이용한 남마리아나 아크 해저화산 열수분출공 탐사

이판묵(Pan-Mook Lee),전봉환(Bong-Huan Jun),백혁(Hyuk Baek),김방현(Banghyun Kim),심형원(Hyungwon Shim),박진영(Jin-Yeong Park),유승열(Seong-Yeol Yoo),정우영(Woo-Young Jeong),백세훈(Sehun Baek),김웅서(Woong-Seo Kim) 한국해양공학회 2016 韓國海洋工學會誌 Vol.30 No.5

This paper presents the explorations of hydrothermal vents located in the Marina Arc and Back Arc Basin using the deep-sea ROV Hemire. These explorations were conducted by KRISO and KIOST to demonstrate the capability of Hemire in various applications for deep-sea scientific research. The missions included the following: (1) to search the reported vents, (2) conduct visual inspections, (3) deploy/recover a sediment trap and bait traps, (4) sample sediment/water/rock, (5) measure the magnetic field at the vent site, and (6) acquire a detailed map using multi-beam sonar near the bottom. We installed three HD cameras for precise visual inspection, a high-temperature thermometer, a three-component magnetometer, and a multi-beam sonar to acquire details of the bottom contour or identify vents in the survey area. The explorations were performed in an expedition from March 23 to April 5, 2016, and the missions were successfully completed. This paper discusses the operational process, navigation, and control of Hemire, as well as the exploration results.

초음파 거리계를 이용한 무인잠수정의 수중 복합 항법시스템

이판묵(PAN-MOOK LEE),전봉환(BONG-HWAN JEON),김시문(SEA-MOON KIM),이종무(CHONG-MOO LEE),임용곤(YONG-KON LIM),양승일(SEUNG-IL YANG) 한국해양공학회 2004 韓國海洋工學會誌 Vol.18 No.4

This paper presents a hybrid underwater navigation system for unmanned underwater vehicles, using an additional range sonar, where the navigation system is based on inertial and Doppler velocity sensors. Conventional underwater navigation systems are generally based on an inertial measurement unit (IMU) and a Doppler velocity log (DVL), accompanying a magnetic compass and a depth sensor. Although the conventional navigation systems update the bias errors of inertial sensors and the scale effects of DVL, the estimated position slowly drifts as time passes. This paper proposes a measurement model that uses the range sonar to improve the performance of the IMU-DVL navigation system, for extended operation of underwater vehicles. The proposed navigation model includes the bias errors of IMU, the scale effects of VL, and the bias error of the range sonar. An extended Kalman filter was adopted to propagate the error covariance, to update the measurement errors, and to correct the state equation, when the external measurements are available. To illustrate the effectiveness of the hybrid navigation system, simulations were conducted with the 6-d.o.f. equations of motion of an AUV in lawn-mowing survey mode.

이산 가변구조제어기를 이용한 자율무인잠수정의 심도제어

이판묵(Pan-Mook Lee),홍석원(Seok-Won Hong),전봉환(Bong-Hwan Jeon) 한국해양공학회 1997 韓國海洋工學會誌 Vol.11 No.4

This paper presents a discrete-time sliding mode control of an autonomous underwater vehicle with parameter uncertainties and long sample interval based on discrete variable structure system. Although conventional sliding mode control techniques are robust to system uncertainties, in the case of the system with long sample interval, the sliding control system reveals chattering phenomenon and even makes the system unstable. This paper considers the AUV which acquires position informations from a surface ship through an acoustic telemetry system with a certain discrete interval. The control system is designed on the basis of a Lyapunov function and a sufficient condition of the switching gain to make the system stable is given. Each component of the switching gain can be determined separately one another. The controller is robust to the uncertainties, and reaching condition of the control system is satisfied for any initial condition. This control law is a generalized form of the discrete sliding mode control and reduce the chattering problem considerably. Motion control of the AUV in the vertical plane shows the effectiveness of the proposed technique.

원격무인 잠수정의 자기동조 위치제어

이판묵(Pan-Mook Lee) 한국해양공학회 1989 韓國海洋工學會誌 Vol.3 No.2

In general, a remotely operated vehicle(ROV) operates at deep sea. The control system of ROV is composed of two local loops ; the first loop placed on the surface vessel monitors and manipulates the attitude of the ROV using joystick, and the second part on the ROV automatically controls thrusters and acquires positional data.<br/> This paper presents a position control simulation of a ROV using an adaptive controller and discusses the control effects of two different conditions. The design of an adaptive control system is obtained by the application of a self-tuning controller with the minimization of an appropriate cost function. The parameters of the control system are estimated by a recursive least square method(RLS). In the simulation, a Runge-Kutta method is used for the numerical integration and the generated outputs are obtained by adding measurement errors. Additionally, this paper discusses the mathematical modelling of a ROV and make a survey of control systems.

고정기준점에 대한 거리측정 신호를 이용하는 자율무인잠수정의 수중항법

이판묵(PAN-MOOK LEE),전봉환(BONG-HUAN JUN),임용곤(YONG-KON LIM) 한국해양공학회 2008 韓國海洋工學會誌 Vol.22 No.4

This paper presents an underwater navigation system based on range measurements from a known reference station fixed on the sea bottom or floated at surface with a buoy, for which the system is extended to 3-dimensional coordinates. We formulated a state equation in polar coordinates and constitutedan extended Kalman filter for discrete-time implementation of the navigation algorithm. The autonomous underwater vehicle, ISiMI, cruising with a constant speed can estimate its trajectory using just range measurements and additional depth, heading, and pitch sensors. Simulation studies were performed to evaluate the underwater navigation of the maneuvering AUV with range measurements. We modulated the sample rate of range measurements to evaluate the effect of the update rate, and changed the initial position error of the AUV to check the robustness toestimation errors. Simulation results illustrates that the extended navigation system provides convergence of the state estimates. The navigation system was conditionally stable when it had initial position errors.

신경회로망을 이용한 AUV의 시스템 동정화 및 응용

이판묵(Pan-Mook Lee),이종식(Jong-Sik Lee) 한국해양공학회 1994 韓國海洋工學會誌 Vol.8 No.2

Dynamics of AUV has heavy nonlinearities and many unknown parameters due to its bluff shape and low cruising speed. Intelligent algorithms, therefore, are required to overcome these nonlinearities and unkown system dynamics. Several identification techniques have been suggested for the application of control of underwater vehicles during last decade. This paper applies the neural network to identification and motion control problem of AUVs. Nonlinear dynamic systems of an AUV are identified using feedforward neural network. Simulation results show that the learned neural network can generate the motion of AUV. This paper, also, suggest an adaptive control scheme up-dates the controller weights with reference model and feedforward neural network using error back propagation.

두개의 초음파 거리계를 이용한 관성센서 기반의 의사 장기선 (Pseudo-LBL) 복합항법 알고리듬

이판묵(PAN-MOOK LEE),전봉환(BONG-HUAN JUN),홍석원(SEOK-WON HONG),임용곤(YONG-KON LIM),양승일(SEUNG-IL YANG) 한국해양공학회 2005 韓國海洋工學會誌 Vol.19 No.5

This paper presents an integrated underwater navigational algorithm for unmanned underwater vehicles, using additional two-range transducers. This paper proposes a measurement model, using two range measurements, to improve the performance of an IMU-DVL (inertial measurement unit - Doppler velocity log) navigation system for long-time operation of underwater vehicles, excluding DVL measurement. Extended Kalman filter was adopted to propagate the error covariance, to update the measurement errors, and to correct the state equation when the external measurements are available. Simulation was conducted with the 6-d.o.f. nonlinear numerical model of an AUV in lawn-mowing survey mode, at current flow, where the velocity information is unavailable. Simulations illustrate the effectiveness of the integrated navigation system, assisted by the additional range measurements without DVL sensing.

퍼지추론을 이용한 무인잠수정의 하이브리드 항법 시스템

이판묵(Pan-Mook Lee),이종무(Chong-Moo Lee),정성욱(Seong-Wook Cheong) 한국해양공학회 1997 韓國海洋工學會誌 Vol.11 No.3

본 연구를 통하여, 자세 선수각 유속 계측 시스템 AHFRS와 초음파 측위시스템 SSBL을 이용하여 거친 해상에서 운항중인 잠수정의 정밀 위치추적을 수행할 수 있는 하이브리드 항법 시스템을 제시하였다. SSBL의 계측 신호와 AHFRS의 오차모델을 이용하여 칼만 필터를 구성하였으며, 퍼지추론을 이용하여 오차 및 센서 고장이 포함된 외부 계측신호의 신뢰도를 결정하는 방법을 구현하였다. 신호변동폭이 작은 경우(소프트 센서 고장) 및 큰 경우 (하드 센서 고장) 각각에 대하여 제안된 방법을 적절하게 가중치를 조정하는 기능을 보유하여, 본 연구의 방법에 의한 결과가 단순히 필터 만을 사용하는 경우 보다 잠수정의 위치 추적 성능이 현저하게 개선되는 것을 보였다. 따라서, 소나 위치추적장치를 장착한 무인 잠수정이 주변 환경에 따라 교란을 받게 되는 단점을 극복하고 위치추적 성능을 개선시키는 방법으로써, 유속계, 방위계 및 자세 센서를 탑재하고 본 연구에서 개발된 항법 시스템을 이용하면 잠수정의 위치추적 성능을 현저하게 개선시킬 수 있다. This paper presents a hybrid navigation system for AUV to locate its position precisely in rough sea. The tracking system is composed of various sensors such as an inclinometer, a tri-axis magnetometer, a flow meter, and a super short baseline(SSBL) acoustic position tracking system. Due to the inaccuracy of the attitude sensors, the heading sensor and the flowmeter, the predicted position slowly drifts and the estimation error of position becomes larger. On the other hand, the measured position is liable to change abruptly due to the corrupted data of the SSBL system in the case of low signal to noise ratio or large ship motions. By introducing a sensor fusion technique with the position data of the SSBL system and those of the attitude heading flowmeter reference system (AHFRS), the hybrid navigation system updates the three-dimensional position robustly. A Kalman filter algorithm is derived on the basis of the error models for the flowmeter dynamics with the use of the external measurement from the SSBL. A failure detection algorithm decides the confidence degree of external measurement signals by using a fuzzy inference. Simulation is included to demonstrate the validity of the hybrid navigation system.

UUV(수중로봇)의 소개와 요소기술

이판묵(Pan-Mook Lee),유선철(Son-Cheol Yu) Korean Society for Precision Engineering 2009 한국정밀공학회지 Vol.26 No.5