Continuous sonar sensing for mobile mini-robots

Klahold, Jürgen; Rautenberg, Jens; Rückert, Ulrich

doi:10.1109/robot.2002.1013381

Cited by 22 publications

(12 citation statements)

References 12 publications

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“…As the inside of the reactor vessel is filled with water during inspection, it is difficult to receive global positioning system (GPS) signals which are typically used in outdoor navigation systems [6]. Additionally because there are many structures in the bottom of the reactor vessel and reflected ultrasonic waves are scattered or the ROV is hidden by structures, it is difficult to apply methods using external sensors on the vehicle such as ultrasonic sensors or multiple cameras [7,8]. On the other hand, there are some methods using CCD camera images and internal mounted gyro sensors [5,9].…”

Section: Localization Methodsmentioning

confidence: 99%

Development of hovering control system for an underwater vehicle to perform core internal inspections

Kobayashi

Okada

2015

Journal of Nuclear Science and Technology

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In this paper, a hovering control system for an underwater vehicle is proposed to support core internal inspections. The system adopted a localization part and a thruster control part. The former utilizes a mapmatching method, referring cross-sectional shape data cut from a three-dimensional computer aided design (CAD) and structural shapes measured by a laser range system for horizontal positioning. A pressure sensor provides vertical positioning. The latter utilizes the thrust vector control, or reference thrust vectors are converted to each propeller thrust based on the vehicle's geometric structure. Experiments to evaluate performance of the proposed system were implemented at a mock-up of the reactor bottom part. As a result, it was confirmed that the position was detected with an accuracy of 48 mm, and for a flow velocity of 200 mm/s, it was verified that the vehicle hovered within 77 mm of a target point. Therefore, core internal inspections can be stably carried out even where there is external force caused by water convection flow. IntroductionNuclear power plants require inspections of various structural components to ensure plant reliability. In core internal inspections of nuclear power plants, visual testing (VT) is carried out first, ultrasonic testing and eddy current testing are then implemented if needed. Underwater camera systems (UCSs) and remotely operated vehicles (ROVs) are operated for VT [1,2]. UCSs are easy to operate, but inspection times are long because the cameras cannot move freely and operators need to place them many times in each inspection area. In contrast, ROVs move arbitrarily, so inspection times are reduced by inspecting a wide area at one time. However, while carrying out VT, the pictures of this camera sways and the inspected part moves out of the visual field due to external forces caused by water convection flow, colliding with structures and pulling at the cable connected to the ROV. In that case, the operator stops inspection and controls the ROV not to sway. Therefore, a system that automatically hovers on a target point set by the operator is required.The system is realized by localizing itself in real-time and calculating thrust forces from the position data. In an ocean, a navigation method for autonomous under-

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Section: Localization Methodsmentioning

confidence: 99%

Development of hovering control system for an underwater vehicle to perform core internal inspections

Kobayashi

Okada

2015

Journal of Nuclear Science and Technology

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“…The Modelling and Simulation of the communication subsystem was built by using specific toolboxes as provided by the MATLAB-Simulink toolset, such as the RF Blockset and the Communication System Toolbox. RF communications consist of a transmitter and receiver, used to convert the signal between the baseband signal and assigned channel signal in transmitters and receivers, respectively [4]. SLAM is one of the fundamental aspects that need to be considered for any intelligent autonomous robot which allows the robot to move without any direct predefined information and building a picture of the surrounding environment using all its integrated sensors.…”

Section: Introductionmentioning

confidence: 99%

Modelling and simulation of the Autonomous Underwater Vehicle (AUV) Robot

2015

Weber, T., McPhee, M.J. And Anderssen, R.S. (Eds) MODSIM2015, 21st International Congress on Modelling and Simulation

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Autonomous underwater vehicles (AUV) have been used widely in the oceanic applications for many purposes, such as maritime fishery study, the installation of underwater pipelines in the oil and gas industry as well as to support offshore engineering, and mine hunting and defence applications. Projects in the development, manufacturing and testing of AUVs are complex, requiring a large investment of time, money and effort. Therefore, the simulation of the AUVs has been identified as being cost effective and time saving, as simulation is a vital step in understanding the behaviour and operation of the system before its actual deployment in the field. A number of subsystems must be considered for building a successful AUV simulator, these are the Inertial Navigation System (INS), Machine Vision, Sonar, Communication (underwater and on surface), and the Simultaneous Localization and Mapping (SLAM) module systems. This paper discusses the methods and the outcomes of the feasibility study of the AUV simulator under investigation.

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“…Nowadays, it is necessary for most autonomous mobile robots to recognize the distance between their own location and obstacles. In detection methods employing acoustical systems, proposed in several papers [1][2][3][4], ultrasonic waves are used because of easy reflection from structures. The advantages of ultrasonic systems, compared with others, are low cost, small size, and simple hardware.…”

Section: Introductionmentioning

confidence: 99%