Experimental and Computational Methodology for the Determination of Hydrodynamic Coefficients Based on Free Decay Test: Application to Conception and Control of Underwater Robots

Abstract

Hydrodynamic coefficients are essential for the development of underwater robots; in particular, for their design and navigation control. To obtain these coefficients, several techniques exist. These methods are usually experimental, but, more recently, some have been designed by a combination of experiments with computational methods based on Computational Fluid Dynamics (CFD). One method for obtaining the hydrodynamic coefficients of an ROV (Remote Operated Vehicle) is by using an experimental PMM (Planar Motion Mechanism) or CWC (Circular Water Channel); however, the use of these experimental infrastructures is costly. Therefore, it is of interest to obtain these coefficients in other ways, for example, by the use of simple experiments. The Free Decay Test is an ideal type of experiment, as it has a low cost and is simple to implement. In this paper, two different free decay tests were carried out, to which three different methods for obtaining coefficients were applied. They were compared with results obtained by CFD simulation to conduct a statistical analysis in order to determine their behaviours. It was possible to obtain values of the drag and added mass coefficients for the models analysed, where the values were obtained for an Underwater Drone Robot (UDrobot).

Mini-AUV Hydrodynamic Parameters Identification via CFD Simulations and Their Application on Control Performance Evaluation

“…Figure 4 shows that the position, velocity, and acceleration of the mini-AUV, as provided by the ANSYS CFX module, are depicted, highlighting that such results correspond to its motion in . Recalling [ 11 , 12 , 13 , 14 , 15 , 44 , 45 ], the plots can be considered to describe a close-to-reality behavior whose evidence is shown in Figure 5 [ 11 , 12 , 13 ] (Figures taken from [ 11 , 12 , 13 ] for comparison purposes only, no copyright infringement is intended.).…”

“…The experimental methodology that was presented in [ 11 , 12 , 13 , 14 , 15 ] was considered to identify the hydrodynamic parameters of the vehicle. This methodology implies the study of the performance of the vehicle in only one DOF at a time.…”

“…In order to estimate the hydrodynamic parameters of a prescribed underwater vehicle, different experimental methodologies have been reported in the literature [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ], yet, the majority of them require the implementation of top-technological expensive gadgets and tools, which makes the design task difficult for those researchers whose budget and facilities are an issue to overcome. In this regard, the implementation of Computed Fluid Dynamics (CFD) software and other computational resources has emerged as an alternative to conceive the vehicles at the first stages of research.…”

Su Altı Araçlarında İtici Motorların Farklı Açılarda Konumlandırılmasının Cad Ortamında İtki Kuvvetine Etkisinin Analiz Uygulamaları

“…In an unconnected fluid domain, an infinitely large fluid domain is needed to study the damping force acting on the ROV. This is impractical in both CFD and experimental process (Cely, Saltaren, Portilla, Yakrangi, & Rodriguez-Barroso, 2019). Because the environment being analyzed is a computational area, it was observed that the fluid field dimensions directly affect the resulting thrust Force values as a result of the flow analysis experiments.…”

Design and Construction of an ROV for Underwater Exploration

“…Nevertheless, aspects such as the ROV's autonomy, efficiency in energy consumption, processing and information storage, hydrodynamic structure, position control, and limitations in communication are some of the topics on which current research could contribute [34][35][36][37]. Another factor that can affect the ROV design and implementation is the high cost involved, but it is important to consider an adequate balance between the cost and the functionality of the system in relation to its application [38][39][40][41].…”