• Title/Summary/Keyword: depth controller

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Study on Dynamics Modeling and Depth Control for a Supercavitating Underwater Vehicle in Transition Phase (초공동 수중운동체의 천이구간 특성을 고려한 동역학 모델링 및 심도제어 연구)

  • Kim, Seon Hong;Kim, Nakwan
    • Journal of the Society of Naval Architects of Korea
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    • v.51 no.1
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    • pp.88-98
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    • 2014
  • A supercavitation is modern technology that can be used to reduce the frictional resistance of the underwater vehicle. In the process of reaching the supercavity condition which cavity envelops whole vehicle body, a vehicle passes through transition phase from fully-wetted to supercaviting operation. During this phase of flight, unsteady hydrodynamic forces and moments are created by partial cavity. In this paper, analytical and numerical investigations into the dynamics of supercavitating vehicle in transition phase are presented. The ventilated cavity model is used to lead rapid supercavity condition, when the cavitation number is relatively high. Immersion depth of fins and body, which is decided by the cavity profile, is calculated to determine hydrodynamical effects on the body. Additionally, the frictional drag reduction associated by the downstream flow is considered. Numerical simulation for depth tracking control is performed to verify modeling quality using PID controller. Depth command is transformed to attitude control using double loop control structure.

Depth Control of Underwater Glider by Lyapunov's Direct Method (리야푸노프 직접법에 의한 수중 글라이더의 깊이 제어)

  • Joo, Moon Gab
    • IEMEK Journal of Embedded Systems and Applications
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    • v.12 no.2
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    • pp.105-112
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    • 2017
  • To control the depth of an underwater glider, a control method by using Lyapunov's direct method is proposed. The underwater glider has a torpedo-shape hull, a movable mass in the hull, and an inflatable buoyancy bag in the hull, but doesn't have large wings that increase the lift force for the conventional underwater glider. The control laws to adjust the position of the movable mass and the mass of the inflatable buoyancy bag are derived. For a selected speed and an angle of attack, we simulated the operation of the underwater glider using Matlab/Simulink. The efficiency of the proposed controller is shown in the fact that the control effort is active during only a short period of time when the zigzag trajectory is changed from downward to upward or vice versa.

Automatic Control of the Combine(III) -Automatic Feeding Depth Control of the Head-feed Combine- (콤바인의 자동제어(自動制御)에 관한 연구(硏究)(III) -자탈형(自脱型) 콤바인의 탈곡(脱穀)깊이 자동제어(自動制御)-)

  • Chung, C.J.;Kim, S.C.;Nam, K.H.
    • Journal of Biosystems Engineering
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    • v.14 no.2
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    • pp.94-103
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    • 1989
  • This study was intended to develop the automatic feeding depth control system of the head-feed combine which could feed the rice head into threshing unit at the optimal depth regardless of plant height and uneven ground surface. In the control system, one-board microcomputer was used for the controller instead of conventional electric circuits. Field test of the combine equipped with the control system was conducted to evaluate its overall performance. It was also investigated how the location and time delay of rice head sensor affect the system performance.

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Disturbance countermeasurement of depth control system using adaptive notch filter (적응노치필터를 이용한 심도제어시스템 외란처리)

  • 김윤호;윤형식;임재환;이석필;박상희
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.86-89
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    • 1992
  • One of the most difficult problems in depth control for underwater vehicle is the effect of seaway disturbance. One component of the seaway forces is of large magnitude with a relatively narrow-band, first order component. The other component is generaly of somewhat smaller magnitude, second order component. Since the magnitude of the first order component is generally much greater than the compensating force that can be generating by the planes, it is undesirable for the controller to generate a control command. In this paper, we disigned adaptive notch filtering system using filter bank structure. Energies of each band-passed signal are obtained by MA(Moving Average) method and compared to produce center frequency. By adapting this parameter to notch filter, 1st order seaway disturbance can be removed, which lead to the improvement of automatic depth control system.

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Development of Holder Ampere Control Arc Welding System and It′s Usefulness (홀더 암페어 조절 아크용접 시스템 개발 및 그 유용성)

  • 이용복
    • Proceedings of the KWS Conference
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    • 1994.10a
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    • pp.89-92
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    • 1994
  • According to the industrial development welding technology is necessitated to develop in the direction of full automation, high efficiency, energy saving, and full safety. In this study, thus, a simple holder ampere controller for welding systems is developed and applied to arc welders and its capability is examined and tested. The results are as follows: 1. It has a simple structure, since the primary AC power for the welder can be directly control led using a triac. 2. It can control the electric power strength in several steps as well as on and off easily, since a small-sized variable resistance is installed in the small controller on the welding holder. 3. In real field applications a welding system with this controller increases the working efficiency greatly compare to the conventional arc welders without the system, because the controller can control the ampere onsite far from the main power supply. 4. It can reduce the probability of the electrical mishap due to electrical leakage, since the electricity is disconnected as soon as the switch is off or welding person's hand is taken off from the welder after the work or for rest. 5. It can control the welding depth in the beginning and do the crater treatment well in the ending of welding, since it always supplies the relevent amount of electrical current. Therefore, it can improve the mechanical properties of the welding zone.

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Design of T-S Fuzzy Model Based H Controller for Diving Control of AUV: An LMI Approach (무인 잠수정의 깊이 제어를 위한 T-S 퍼지 모델 기반 H 제어기 설계: 선형 행렬 부등식 접근법)

  • Jun, Sung-Woo;Kim, Do-Wan;Lee, Ho-Jae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.22 no.4
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    • pp.441-447
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    • 2012
  • This paper presents a design technique of a Takagi-Sugeno (T-S) fuzzy-model-based $H_{\infty}$ controller for autonomous underwater vehicles (AUVs). The design procedure aims to render the stabilizing controller which satisfies performance of the diving control for AUVs in the presence of the disturbance. A nonlinear AUV is modeled by the T-S fuzzy system through the sector nonlinearity. By using Lyapunov function, the sufficient conditions are derived to guarantee the performance of robust depth control in the format of linear matrix inequality (LMI). To succeed for diving control of AUV, we add the constraints on the diving and pitch angles in the LMI conditions. Through the simulation, we confirm the effectiveness of the proposed methodology.

Implementation of Human Positioning Monitoring Device for Underwater Safety (수중안전을 위한 인체 위치추적 모니터링 장치 구현)

  • Jong-Hwa Yoon;Dal-Hwan Yoon
    • Journal of IKEEE
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    • v.27 no.3
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    • pp.225-233
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    • 2023
  • This paper implements a system that monitors human body lifting information in the event of a marine accident. The monitoring system performs ultrasonic communication through a lifting device controller that transmits underwater environment information, and LoRa communication is performed on the water to provide GPS information within 10 km to the control center or mother ship. The underwater lifting controller transmits pneumatic sensor, gyro sensor, and temperature sensor information. In an environment where the underwater conditions increase by one atmosphere of water pressure every 10m in depth, and the amount of air in the instrument decreases by half compared to land, a model of a 60kg underwater mannequin is used. Using one 38g CO2 cartridge in the lifting appliance SMB(Surface Maker Buoy), carry out a lifting appliance discharge test based on the water level rise conditions within 10 sec. Underwater communication constitutes a data transmission environment using a 2,400-bps ultrasonic sensor from a depth of 40m to 100m. The monitoring signal aims to ensure the safety and safe human structure of the salvage worker by providing water depth, water temperature, and directional angle to rescue workers on the surface of the water.

Heading Control of URI-T, an Underwater Cable Burying ROV: Theory and Sea Trial Verification (URI-T, 해저 케이블 매설용 ROV의 선수각 제어 및 실해역 검증)

  • Cho, Gun Rae;Kang, Hyungjoo;Lee, Mun-Jik;Li, Ji-Hong
    • Journal of Ocean Engineering and Technology
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    • v.33 no.2
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    • pp.178-188
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    • 2019
  • When burying underwater cables using robots, heading control is one of the key functions for the robots to improve task efficiency. This paper addresses the heading control issue for URI-T, an ROV for underwater construction tasks, including the burial and maintenance of cables or small diameter pipelines. Through modeling and identifying the heading motion of URI-T, the dynamic characteristics and input limitation are analyzed. Based on the identification results, a PD type controller with appropriate input treatment is designed for the heading control of URI-T. The performance of the heading controller was verified in water tank experiments. The field applicability of the proposed controller was also evaluated through the sea trial of URI-T at the East Sea, with a water depth of 500 m.

Floop: An efficient video coding flow for unmanned aerial vehicles

  • Yu Su;Qianqian Cheng;Shuijie Wang;Jian Zhou;Yuhe Qiu
    • ETRI Journal
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    • v.45 no.4
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    • pp.615-626
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    • 2023
  • Under limited transmission conditions, many factors affect the efficiency of video transmission. During the flight of an unmanned aerial vehicle (UAV), frequent network switching often occurs, and the channel transmission condition changes rapidly, resulting in low-video transmission efficiency. This paper presents an efficient video coding flow for UAVs working in the 5G nonstandalone network and proposes two bit controllers, including time and spatial bit controllers, in the flow. When the environment fluctuates significantly, the time bit controller adjusts the depth of the recursive codec to reduce the error propagation caused by excessive network inference. The spatial bit controller combines the spatial bit mask with the channel quality multiplier to adjust the bit allocation in space to allocate resources better and improve the efficiency of information carrying. In the spatial bit controller, a flexible mini graph is proposed to compute the channel quality multiplier. In this study, two bit controllers with end-to-end codec were combined, thereby constructing an efficient video coding flow. Many experiments have been performed in various environments. Concerning the multi-scale structural similarity index and peak signal-to-noise ratio, the performance of the coding flow is close to that of H.265 in the low bits per pixel area. With an increase in bits per pixel, the saturation bottleneck of the coding flow is at the same level as that of H.264.

Image-based Robust Control of Robot Manipulators with Image Jacobian and Dynamics Uncertainties (영상 자코비안 및 동특성 불확실성을 포함하는 로봇 매니퓰레이터의 영상기반 강인제어)

  • Kim, Chin-Su;Mo, Eun-Jong;Lee, Kang-Woong
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.10
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    • pp.1047-1052
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    • 2008
  • In this paper, we design an image-based robust controller to compensate uncertainties with image Jacobian and robot dynamics due to uncertain depth measurement and load variations. The proposed controller with eye-in-hand structure has separate terms to compensate each of uncertainties. The ultimate boundedness of the closed-loop system is proved by the Lyapunov approach. The performance of the proposed control system is demonstrated by simulation and experimental results a 5-link robot manipulator with two degree of freedom.