An Investigation of Undulating Shape Adaptation Characteristics of a Hydraulic-Driven Bionic Undulating Robot

2015 ◽  
Vol 743 ◽  
pp. 150-156
Author(s):  
Hai Jun Xu ◽  
Lei Zhang ◽  
Cun Yun Pan ◽  
Xiang Zhang
Keyword(s):  
Mathematical Model ◽  
Middle Part ◽  
Underwater Robot ◽  
Fish Swimming ◽  
Shape Adaptation ◽  
Resource Exploration ◽  
Cfd Method ◽  
Two Sides ◽  
Adaptation Ability ◽  
Undulating Fin

Fish Swimming in MPF (Media and/or Paired Fin) mode has unique hydrodynamic characters and special application in resource exploration underwater. Inspired of the flexible shape and motion of undulating fin of “Nilotic Ghost” fish, a Hydraulic-driven Bionic Undulating Robot (HBUR) is developed and studied in the paper based on CFD method, to investigate the flexible characteristics of shape adaptation and hydrodynamics of HBUR fin, which has great significance for the propelling safety of HBUR underwater. In this paper, a mathematical model is brought forward to indicate the undulating motion of HBUR, which is formed by sequentially and periodically swing motions of Hydraulic Swing Actors (HSAs), and then the CFD method is introduced to calculate the hydro-forces when undulating shape of HBUR fin are distorted, because of distraction underwater. Results show that HBUR could produce propelling forces even when some of the HSAs are restricted from swinging, and shape adaptation ability of different part on HBUR fin is different, where the middle part is worse than the two sides. The propelling forces generated by undulating motion the rest of HBUR fin could be used to get the underwater robot out of trouble itself, and then undulating shape will restore to normal state.

scholarly journals Identical Limb Dynamics for Unilateral Impairments through Biomechanical Equivalence

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 705
Author(s):  
Fatemeh Rasouli ◽  
Kyle B. Reed
Keyword(s):  
Mathematical Model ◽  
Numerical Solution ◽  
Dynamic Models ◽  
Assistive Devices ◽  
Assistive Device ◽  
Human Walking ◽  
Physical Parameters ◽  
Gait Rehabilitation ◽  
And Performance ◽  
Two Sides

Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices.

scholarly journals The application of virtual prototyping methods to determine the dynamic parameters of mobile robot

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Krzysztof Kurc ◽  
Dariusz Szybicki ◽  
Andrzej Burghardt ◽  
Magdalena Muszyńska
Keyword(s):  
Mathematical Model ◽  
Mobile Robot ◽  
Virtual Prototyping ◽  
Design Stage ◽  
Kinematics And Dynamics ◽  
Underwater Robot ◽  
Design Tools ◽  
Dynamic Parameters ◽  
Mechatronic Design

Abstract The paper presents methods used to determine the parameters necessary to build a mathematical model of an underwater robot with a crawler drive. The parameters present in the dynamics equation will be determined by means of advanced mechatronic design tools, including: CAD/CAE software andMES modules. The virtual prototyping process is described as well as the various possible uses (design adaptability) depending on the optional accessories added to the vehicle. A mathematical model is presented to show the kinematics and dynamics of the underwater crawler robot, essential for the design stage.

Design and Fabrication of a Three-Axis Force Sensor for Underwater Robot Fingers and a Method for Decreasing Error

2013 ◽  
Vol 475-476 ◽  
pp. 411-414
Author(s):  
Ming Hua Luo ◽  
Qing Mei Yao ◽  
Chun Wei Pan ◽  
Xin Jian Liu
Keyword(s):  
Mathematical Model ◽  
Simple Structure ◽  
Force Sensor ◽  
Underwater Robot ◽  
Lead Wire ◽  
Finger Force ◽  
Electronic Circuits ◽  
Block Method ◽  
Proposed Model ◽  
Temperature And Pressure

In this paper, we present a new mathematical model of three-axis force sensor for underwater robot fingers. We designed a kind of sensor based on this model which has a simple structure and can be miniaturized easily. By this model, they can be calculated that the magnitude, direction of finger force. Moreover, we present a new compensating method to decrease the error caused with the variation of temperature and pressure of water and caused with bending of the beams by symmetrical electronic circuits. We proposed compensation block method to solve the problem of heavy lead wire which affecting finger moving in underwater. Finally, an experiment is performed to verify the proposed model.

Selection of Method for Underwater Robot Control

2010 ◽  
Vol 164 ◽  
pp. 149-154 ◽  
Author(s):  
Piotr Szymak
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Numerical Analysis ◽  
Automatic Control ◽  
Robot Control ◽  
Underwater Vehicle ◽  
Underwater Robot ◽  
Underwater Robots ◽  
The Mathematical Model ◽  
Selection Of

Automatic control of motion of underwater robots, particularly along desired trajectory, requires application of proper controllers taking into account dynamics of the underwater robot and features of the marine environment. In the paper the mathematical model of an underwater vehicle [2] and the architecture of designed control system [4] have been presented. Moreover, selected results of numerical analysis in the form of comparison of different course controllers have been provided.

Numerical Simulation of Indirectly Heated Hot Water Heater

2014 ◽  
Vol 875-877 ◽  
pp. 1693-1697 ◽  
Author(s):  
Richard Lenhard ◽  
Katarína Kaduchová ◽  
Jozef Jandačka
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Finite Volume ◽  
Computational Methods ◽  
Finite Volume Methods ◽  
Hot Water ◽  
Geometrical Parameters ◽  
Water Heater ◽  
Cfd Simulations ◽  
Cfd Method

This paper describes a mathematical model of heating hot water for indirectly heated hot water heater. Using the established mathematical model was carried out simulation of the device to change its geometrical parameters. Based on the results of simulations was carried out optimization of indirectly heated hot water heater for hot water. Subsequently been made CFD simulations of the device, and those were compared with a mathematical model to verify the accuracy of the proposed mathematical model of heating hot water for indirectly heated hot water heater. Computational methods based on finite volume methods (CFD method) have proved very useful in optimizing indirectly heated hot water heater.

Numerical Prediction of Bow-Flared Slamming on ULCS in Oblique Waves

2018 ◽  
Author(s):  
Hang Xie ◽  
Huilong Ren ◽  
Hui Li ◽  
Kaidong Tao
Keyword(s):  
Short Term ◽  
Oblique Waves ◽  
Commercial Code ◽  
Torque Moment ◽  
Motion Features ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Two Sides ◽  
Term Analysis

Bow-flared slamming loads of ULCS in oblique waves were studied systematically. Firstly, relative motion features between ship and wave were analyzed by seakeeping theory. The result shows the transverse and roll motion cannot be ignored in oblique waves. Secondly, a long-term and short-term analysis was applied to obtain the parameters of equivalent design wave. Then slamming pressure of two bow-flared sections with three kinds of motions was predicted by using the Computational Fluid Dynamics (CFD) method in commercial code FLUENT. Pressure characteristics in different wave directions were discussed and the results show slamming loads in some oblique wave cases are larger than that in the head sea. And the torque moment and transverse force caused by asymmetrical pressure distribution on the two sides should be drawn more attention.

scholarly journals Study on a Dynamic Numerical Model of an Underground Air Tunnel System for Cooling Applications—Experimental Validation and Multidimensional Parametrical Analysis

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1236 ◽  
Author(s):  
Liang Tang ◽  
Zhengxuan Liu ◽  
Yuekuan Zhou ◽  
Di Qin ◽  
Guoqiang Zhang
Keyword(s):  
Mathematical Model ◽  
Computational Complexity ◽  
Numerical Model ◽  
Experimental Validation ◽  
Cooling Capacity ◽  
Tube Diameter ◽  
Outlet Temperature ◽  
Air Velocity ◽  
Cfd Method ◽  
Tunnel System

The underground air tunnel system shows promising potentials for reducing energy consumption of buildings and for improving indoor thermal comfort, whereas the existing dynamic models using the computational fluid dynamic (CFD) method show computational complexity and are user-unfriendly for parametrical analysis. In this study, a dynamic numerical model was developed with the on-site experimental calibration. Compared to the traditional CFD method with high computational complexity, the mathematical model on the MATLAB/SIMULINK platform is time-saving in terms of the real-time thermal performance prediction. The experimental validation results indicated that the maximum absolute relative deviation was 3.18% between the model-driven results and the data from the on-site experiments. Parametrical analysis results indicated that, with the increase of the tube length, the outlet temperature decreases with an increase of the cooling capacity whereas the increasing/decreasing magnitude slows down. In addition, the system performance is independent on the tube materials. Furthermore, the outlet air temperature and cooling capacity are dependent on the tube diameter and air velocity, i.e., a larger tube diameter and a higher air velocity are more suitable to improve the system’s cooling capacity, and a smaller tube diameter and a lower air velocity will produce a more stable and lower outlet temperature. Further studies need to be conducted for the trade-off solutions between air velocity and tube diameter for the bi-criteria performance enhancement between outlet temperature and cooling capacity. This study proposed an experimentally validated mathematical model to accurately predict the thermal performance of the underground air tunnel system with high computational efficiency, which can provide technical guidance to multi-combined solutions through geometrical designs and operating parameters for the optimal design and robust operation.

Numerical Study of a Flap Rudder Based on Turbulence Model LES

2011 ◽  
Vol 88-89 ◽  
pp. 240-243 ◽  
Author(s):  
Shu Guang Wu ◽  
Hean Liu
Keyword(s):  
Fluid Dynamics ◽  
Turbulence Model ◽  
Numerical Study ◽  
Boundary Layer Separation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Fluctuation Range ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Two Sides

The flap rudder flow field at Re 1.4×106 is calculated using computational fluid dynamics (CFD) method. Large eddy simulation (LES) turbulence model is adopted. The results shows that boundary layer separation phenomenon appears in flap after the gap, and as angle of flap (AOF) is increased, the separation tends to asymmetry, the pressure fluctuation range is becomes higher. There is no eddy in gap when AOF is 0°, but as AOF increases, the eddy in gap appears because of the pressure difference between two sides of the rudder.

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