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.

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.

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.

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.

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.

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.

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.

초음파 거리계를 갖는 수중복합항법시스템의 초기오차 수렴 특성

이판묵(PAN-MOOK LEE),전봉환(BONG-HUAN JUN),김시문(SEA-MOON KIM),최현택(HYUN TAEK CHOI),이종무(CHONG-MOO LEE),김기훈(KIHUN KIM) 한국해양공학회 2005 韓國海洋工學會誌 Vol.19 No.6

Initial alignment and localization are important topics in inertial navigation systems, since misalignment and initial position error wholly propagate into the navigation systems and deteriorate the performance of the systems. This paper presents the error convergence characteristics of the hybrid navigation system for underwater vehicles initial position, which is based on an inertial measurement unit (IMU) accompanying a range sensor. This paper demonstrates the improvement on the navigational performance of the hybrid system with the range information, especially focused on the convergence of the estimation of underwater vehicles initial position error. Simulations are performed with experimental data obtained from a rotating arm test with a fish model. The convergence speed and condition of the initial error removal for random initial position errors are examined with Monte Carlo simulation. In addition, numerical simulation is conducted with an AUV model in lawn-mowing survey mode to illustrate the error convergence of the hybrid navigation system for initial position error.

자율무인잠수정의 수중 도킹을 위한 비쥬얼 서보 제어 알고리즘

이판묵(PAN-MOOK LEE),전봉환(BONG-HWAN JEON),이종무(CHONG-MOO LEE) 한국해양공학회 2003 韓國海洋工學會誌 Vol.17 No.1

Autonomous underwater vehicles (AUVs) are unmanned, underwater vessels that are used to investigate sea environments in the study of oceanography. Docking systems are required to increase the capability of the AUVs, to recharge the batteries, and to transmit data in real time for specific underwater works, such as repeated jobs at sea bed. This paper presents a visual servo control system used to dock an AUV into an underwater station. A camera mounted at the nose center of the AUV is used to guide the AUV into dock. To create the visual servo control system, this paper derives an optical flow model of a camera, where the projected motions of the image plane are described with the rotational and translational velocities of the AUV. This paper combines the optical flow equation of the camera with the AUVs equation of motion, and derives a state equation for the visual servo AUV. Further, this paper proposes a discrete-time MIMO controller, minimizing a cost function. The control inputs of the AUV are automatically generated with the projected target position on the CCD plane of the camera and with the AUVs motion. To demonstrate the effectiveness of the modeling and the control law of the visual servo AUV, simulations on docking the AUV to a target station are performed with the 6-dof nonlinear equations of REMUS AUV and a CCD camera.

USBL, DVL과 선수각 측정신호를 융합한 심해 무인잠수정의 항법시스템

이판묵(Pan-Mook Lee),심형원(Hyungwon Shim),백혁(Hyuk Baek),김방현(Banghyun Kim),박진영(Jin-Yeong Park),전봉환(Bong-Huan Jun),유승열(Seong-Yeol Yoo) 한국해양공학회 2017 韓國海洋工學會誌 Vol.31 No.4

This paper presents an integrated navigation system that combines ultra-short baseline (USBL), Doppler velocity log (DVL), and heading measurements for a deep-sea remotely operated vehicle, Hemire. A navigation model is introduced based on the kinematic relation of the position and velocity. The system states are predicted using the navigation model and corrected with the USBL, DVL, and heading measurements using the Kalman filter. The performance of the navigation system was confirmed through re-navigation simulations with the measured data at the Southern Mariana Arc submarine volcanoes. Based on the characteristics of the measurements, the design process for the parameters of the system modeling error covariance, measurement error covariance, and initial error covariance are presented. This paper reviews the influence of the outliers and blackout of the USBL and DVL measurements, and proposes an outlier rejection algorithm that is robust to USBL blackout. The effectiveness of the method is demonstrated with re-navigation for the data that includes USBL blackouts.