Development of Dam Inspection Underwater Robot

Hirai, Hiroyasu; Ishii, Kazuo

doi:10.2991/jrnal.k.190531.004

Cited by 17 publications

(5 citation statements)

References 4 publications

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“…As important infrastructure for river flood control projects, underwater dams are of great significance to regulate the temporal and spatial distribution of water resources and build disaster prevention systems. However, underwater dams always suffer from various uncertain defects, such as cracks and holes caused by geological environment, water flow and self-aging [1]. More serious is that tiny cracks in the concrete will develop from the surface to the inside, causing the concrete to break, which can lead to dangerous accidents [2].…”

Section: Problem Statementmentioning

confidence: 99%

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A fine extraction algorithm for image-based surface cracks in underwater dams

Xin¹,

Fan²,

Shi³

et al. 2022

Meas. Sci. Technol.

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Under the action of water erosion and self-aging action, reservoir dams are prone to have cracks, affecting the safe operation. Underwater visual imaging can be used to detect dam surface cracks, but the spalling, aquatic plants and suspended sediments result in low image contrast and complex backgrounds. With the use of unsupervised machine learning, this paper proposes a fine segmentation and extraction algorithm for image-based dam surface cracks. Firstly, the adaptive histogram equalization is used to make the uneven illumination areas of underwater surface images be even illumination areas, whose statistical characteristics is calculated under the linear spatial filtering. Secondly, the extraction problem of interested crack areas after dodging preprocess is transformed into calculating the distance of image block cluster center, which can distinguish the image blocks of crack features from the background interference features. Thirdly, the fine extraction of crack images is carried out in consideration of the connected domains and morphological features, and the posterior probability of image sample category is obtained based on the soft clustering of Gaussian mixed model. Finally, different extraction algorithms related to surface cracks are evaluated in extensive experiments. The results validate the superior performance of the proposed extraction algorithm with 90.1% extraction accuracy, 6.5% missing alarm rate, and 7.2% false alarm rate.

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Section: Problem Statementmentioning

confidence: 99%

“…After calculating the posterior probability v i j of each point, the parameters of the jth Gaussian model are estimated. When the image sample points {x (1) , x (2) , . .…”

Section: Mathematical Modeling Of Crack Extractionmentioning

confidence: 99%

A fine extraction algorithm for image-based surface cracks in underwater dams

Xin¹,

Fan²,

Shi³

et al. 2022

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…In recent years, the demand for inspecting, cleaning, and maintaining various underwater structures has surged, resulting in the creation of various underwater examination robots [1][2][3][4][5][6][7] designed to undertake hazardous tasks in place of humans. In these applications, tasks have become increasingly intricate, necessitating higher levels of mobility and stability in robots.…”

Section: Introductionmentioning

confidence: 99%

Study on the Adsorption Performance of a Vortex Suction Cup under Varying Diameters of Underwater Structure Tubes

Tang,

Du,

Liu

et al. 2024

JMSE

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In certain precision work scenarios, underwater robots require the ability to adhere to surfaces in order to perform tasks effectively. An efficient and stable suction device plays a pivotal role in the functionality of such underwater robots. The vortex suction cup, distinguished by its uncomplicated design, high suction efficiency, and capability for non-contact adhesion, holds significant promise for integration into underwater robotic systems. This paper presents a novel design for a vortex suction cup and investigates its suction force and torque when encountering surfaces with varying curvature radii using Computational Fluid Dynamics (CFD) simulations and experimental testing. These findings offer valuable insights for the development of robots capable of adapting to underwater structures of different dimensions. Results from both experiments and simulations indicate that reducing the curvature radius of the adhered surface results in a decrease in suction force and an increase in torque exerted on the suction cup. As the adhered surface transitions from flat to a curvature radius of 150 mm, the adhesion force of our proposed vortex suction cup decreases by approximately 10%, while the torque increases by approximately 20% to 30%. Consequently, the adhesion efficiency of the suction cup decreases by about 25% to 30%.

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“…In recent years, underwater climbing robots have been extensively developed so as to replace humans to complete some dangerous and hazardous underwater operations, which include cleaning, maintenance, and inspection of bridges [1,2], dams [3][4][5], ship hulls [6][7][8] and so on. During the research of underwater climbing robots, choosing which kind of suction method is one of the main points that researchers should consider [9,10].…”

Section: Introductionmentioning

confidence: 99%

Study on the Optimal Design for Cavitation Reduction in the Vortex Suction Cup for Underwater Climbing Robot

Zhao

Yang

Chen

et al. 2022

JMSE

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In order to adhere to the wall stably in an underwater environment, a vortex suction cup that injects high-pressure water inside via two axisymmetrically side-distributed inlets to create a negative pressure area in the center is the necessary component for the underwater climbing robot (UCR). However, the suction force of this vortex suction cup is reduced and periodically unstable due to unstable cavitation. The aim of this paper is to propose a cavitation reduction optimization method for vortex suction cups and to verify the effectiveness of the optimization. Analyses of this vortex flow, including streamlines, pressure, and cavitation number fluctuations, were carried out by the introduced computational fluid dynamics (CFD) simulating methods based on the multiphase RNG k−ε model to study the periodic fluctuations of the suction force of the original suction cup and the optimized ones. Force measurement and vortex observation experiments were conducted to compare the suction force of the original vortex suction cup and the optimized suction cup, as well as the cavitation and pressure fluctuation phenomenon. Results of simulation and experiments prove the existence of the effect of vortex cavitation on the suction performance and verify the rationality of optimization as well.

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Development of Dam Inspection Underwater Robot

Cited by 17 publications

References 4 publications

A fine extraction algorithm for image-based surface cracks in underwater dams

A fine extraction algorithm for image-based surface cracks in underwater dams

Study on the Adsorption Performance of a Vortex Suction Cup under Varying Diameters of Underwater Structure Tubes

Study on the Optimal Design for Cavitation Reduction in the Vortex Suction Cup for Underwater Climbing Robot

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