http://nopr.niscair.res.in/handle/123456789/6202 http://nopr.niscair.res.in/retrieve/30404 http://nopr.niscair.res.in/handle/123456789/6202 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/6215 Title: Modeling and control of 2-DOF underwater planar manipulator <br/> <br/>Authors: Suboh, Surina Mat; Rahman, Irfan Abd; Arshad, Mohd Rizal; Mahyuddin, Muhammad Nasiruddin <br/> <br/>Abstract: This study investigates the performance of the fuzzy model reference adaptive control method applied on a 2-dof underwater planar manipulator (MIMO system). Takagi-Sugeno fuzzification is chosen for the fuzzy system and the proportional-integral update law is used in the adjustment mechanism to obtain a fast parameters adoption. The present study consists the proposed controller performance in response to the need to control the manipulator with the added terms in the dynamic equation, i.e., hydrodynamic effects brought about by ocean drift. In the presence of the hydrodynamic and hydrostatic effects of sea water, the performance of the controller is analyzed in terms of servo tracking at each of the manipulator joints. The simulation results demonstrate that the actual joint trajectories of the manipulator for both joints asymptotically follow the desired trajectories defined by the reference model even though the plant is subjected to external disturbances and input variations. <br/> <br/>Page(s): 365-371 http://nopr.niscair.res.in/handle/123456789/6214 Title: Underwater crowd flow detection using Lagrangian dynamics <br/> <br/>Authors: Soori, Umair; Arshad, Mohd Rizal <br/> <br/>Abstract: Crowd flow in an underwater scene is used to study fish schooling characteristics. The hydromechanics of fish schooling is quite complicated because it varies in the types of fish underwater. Fish schooling detection contributes toward the study of their locomotion, perception and behavior. For this scenario, we opted to use Lagrangian particle dynamics had been applied to examine the trajectories of an individual particle in the flow. The mathematical algorithm of the Lagrangian Coherent Structure (LCS) is the Finite-time Lyapunov Exponent (FTLE) field the divergence of the particles. The FTLE field is a boundary that divides the flow with respect to its distinct flow dynamics. The algorithm can also do real-time video analyses which can easily be implemented in Autonomous Underwater Vehicles (AUVs). The system is efficient enough to perform the detection of fish schooling as a group flow. <br/> <br/>Page(s): 359-364 http://nopr.niscair.res.in/handle/123456789/6213 Title: Conceptual design of a pressure hull for an underwater pole inspection robot <br/> <br/>Authors: Rahim, Khairul Izman Abdul; Othman, Abdul Rahim; Arshad, Mohd Rizal <br/> <br/>Abstract: The conceptual design of a pressure hull design for an underwater pole inspection system is presented in this study.&nbsp; One of the critical elements in designing the pole-climbing robot is an enclosure for the electronic components that can sustain high pressure and with good protection for underwater application. Four main steps are required in designing the system: selection of the shape of the hull, material selection, hull thickness requirement based on depth limit and safety factor, and end closures design compatible with the hull and design requirements. This study suggests that the preferable material for the proposed structural construction of an underwater pressure hull is aluminum alloy 6061-T6. The methodological approaches applied in the design criteria include analytical calculation and a numerical method for results verification based on the circular cylindrical shape. This paper also proposes that these underwater structures should be able to operate up to 200 m depth. <br/> <br/>Page(s): 352-358 http://nopr.niscair.res.in/handle/123456789/6212 Title: CFD simulation of cooperative AUV motion <br/> <br/>Authors: Husaini, Muhamad; Samad, Zahurin; Arshad, Mohd Rizal <br/> <br/>Abstract: Cooperative AUV performance and efficiency is directly related to its power efficiency. The power consumption for this type of underwater vehicle is influenced by its motion requirement since most of the power is spent for thruster propulsion. Drag force is known as the main parameter in resisting the body motion. In the present study, the behavior of this force is studied by using computational fluid dynamic approach (CFD). Two position arrangement of cooperative AUV was chosen to study the drag variation. First, the distance effect between two AUV was investigated to represent the basic position arrangement of cooperative AUV. Second, the effect of different position arrangement was also investigated. The comparison between distance and position arrangement is discussed in this paper. Present study elucidates that the distance behind the leading AUV does not give much effect to the drag force, but the position arrangement indicated significant influence. <br/> <br/>Page(s): 346-351