Concept Design of the Underwater Manned Seabed Walking Robot

Khan, Asghar; Wang, Liquan; Wang, Gang; Imran, Muhammad; Waqas, Hafiz Muhammad; Zaidi, Asad A.

doi:10.3390/jmse7100366

Cited by 13 publications

(4 citation statements)

References 41 publications

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“…The Ursula ALUV was able to walk underwater, but a faster and more efficient ALUV, Ariel, is able to walk sideways, imitating a crab's gait [42,43]. Khan et al have developed an underwater manned sabed walking robot that is hexapod robot powered by a tether in a boat [44]. While ALUVs overcame some of the issues with surf zone environments, they do not explore the effects of crab dactyls.…”

Section: Introductionmentioning

confidence: 99%

Dactyls and inward gripping stance for amphibious crab-like robots on sand

2021

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Sandy beaches are areas that challenge robots of all sizes, especially smaller scale robots. Sand can hinder locomotion and waves apply hydrodynamic forces which can displace, reorient, or even invert the robot. Crab-like legs and gaits are well suited for this environment and could be used as inspiration for an improved design of robots operating in this terrain. Tapered, curved feet (similar to crab dactyl shape) paired with a distributed inward gripping method are hypothesized to enable better anchoring in sand to resist hydrodynamic forces. This work demonstrates that crab-like legs can withstand vertical forces that are larger than the body weight (e.g. in submerged sand, the force required to lift the robot can be up to 138% of the robot weight). Such legs help the robot hold its place against hydrodynamic forces imparted by waves (e.g. compared to displacement of 42.7 mm with the original feet, crab-like feet reduced displacement to 1.6 mm in lab wave tests). These feet are compatible with walking on sandy and rocky terrain (tested at three speeds: slow, medium, and fast), albeit at reduced speeds from traditional feet. This work shows potential for future robots to utilize tapered and curved feet to traverse challenging surf zone terrain where biological crabs thrive.

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Section: Introductionmentioning

confidence: 99%

Dactyls and inward gripping stance for amphibious crab-like robots on sand

2021

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“…According to the work presented in [31], the onboard operator will control vehicle locomotion and manipulator operation through real-time telemetry and visual interfaces afforded by TC. The study of tether cable dynamics being deployed from surface ship to seabed walking robot, an instance of slack tether in seabed operations, was a primary motivation for the furthering of the finite segment and lumped mass approach.…”

Section: Introductionmentioning

confidence: 99%

Analytical and Numerical Study of Underwater Tether Cable Dynamics for Seabed Walking Robots Using Quasi-Static Approximation

Khan,

Wang,

et al. 2023

JMSE

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In this study, the dynamics of tether cables (TCs) that connect a surface ship and a walking robotic vehicle on the seabed are numerically investigated. The main aim of this study is to develop a reliable prediction model for the dynamic behavior of TCs attached to a seabed walking robot. This system consists of a surface ship, underwater manned seabed walking robot (UMSWR), TC, and winch. The study is comprised of mathematical modeling and numerical simulations of the developed governing equations for the TC dynamics. A relatively simple and efficient mathematical analysis method is proposed to determine the configuration and forces on the TC under a steady state. The problem is solved using the quasi-static technique and lumped mass parameters for discretizing and modeling the dynamics of the TC. Based on the static analysis of the Morrison equation and finite segment method, analytical formulas of the steady-state equation of TC were obtained and solved. The effects of variable water density and variable underwater currents are included in the cable behavior. Consequently, the two-dimensional TC profile and axial tension were estimated in a steady-state configuration. The developed equations were simulated in MATLAB software. Several numerical simulation examples were worked out, demonstrating the accurate performance of the method. Various input parameters of the system and their relationships with the output values were investigated, thereby demonstrating the versatility of the method.

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“…Several studies are available in the literature concerning buckling investigations of non-composite spherical pressure hulls. Both linear and non-linear buckling analyses with geometric and material non-linearity were used in the investigations of spherical hulls [39][40][41][42][43][44][45][46][47][48]. However, the benefit of using composites in the construction of spherical hulls are not yet deeply investigated.…”

Section: Introductionmentioning

confidence: 99%

Design Optimization and Non-Linear Buckling Analysis of Spherical Composite Submersible Pressure Hull

et al. 2020

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This paper describes an optimization study of a spherical composite submersible pressure hull employing a genetic algorithm (GA) in ANSYS. A total of five lay-up arrangements were optimized for three unidirectional composites carbon/epoxy, glass/epoxy, and boron/epoxy. The minimization of the buoyancy factor ( B . F ) was selected as the design optimization objective. The Tsai-Wu and Tsai-Hill failure criteria and buckling strength factor ( λ ) were used as the material failure and instability constraints. To determine the effect of geometric non-linearity and imperfections on the optimized design, a non-linear buckling analysis was also carried out for one selected optimized design in ABAQUS. The non-linear buckling analysis was carried out using the modified RIKS procedure, in which the imperfection size changed from 1 to 10 mm. A maximum decrease of 65.937% in buoyancy factor ( B . F ) over an equivalent spherical steel pressure hull was computed for carbon/epoxy. Moreover, carbon/epoxy displayed larger decreases in buoyancy factor ( B . F ) in the case of 4 out of a total of 5 lay-up arrangements. The collapse depth decreased from 517.95 m to 412.596 m for a 5 mm lowest mode imperfection. Similarly, the collapse depth decreased from 522.39 m to 315.6018 for a 5 mm worst mode imperfection.

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Concept Design of the Underwater Manned Seabed Walking Robot

Cited by 13 publications

References 41 publications

Dactyls and inward gripping stance for amphibious crab-like robots on sand

Dactyls and inward gripping stance for amphibious crab-like robots on sand

Analytical and Numerical Study of Underwater Tether Cable Dynamics for Seabed Walking Robots Using Quasi-Static Approximation

Design Optimization and Non-Linear Buckling Analysis of Spherical Composite Submersible Pressure Hull

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