A Composite Rigid Body Algorithm for Modeling and Simulation of an Underwater Vehicle Equipped With Manipulator Arms

Author(s):  
Mohammad Khalaj Amir Hosseini ◽  
Mohammad Banae ◽  
Ali Meghdari

In this paper modeling and simulation of an underwater vehicle equipped with manipulator arms, using Composite Rigid Body (CRB) algorithm will be discussed. Because of increasing need to Unmanned Underwater Vehicles (UUVs) in oil and gas projects in Persian Gulf, for doing operations such as inspection of offshore jackets, subsea pipelines and submarine cables and also pre installation survey and post laid survey of submarine pipelines and cables, design and construction of “SROV” was developed in Sharif University of Technology, and at design stage behavior of underwater vehicles was studied. In this paper, an efficient dynamic simulation algorithm is developed for an UUV equipped with m manipulators that each of them has N degrees of freedom. In addition to the effects of mobile base, the various hydrodynamic forces exerted on these systems in an underwater environment are also incorporated into the simulation. The effects modeled in this work are added mass, viscous drag, fluid acceleration, and buoyancy forces. For drag forces, the emphasis here is on the modeling of the pressure drag. Recent advances in underwater position and velocity sensing enable real-time centimeter-precision position measurements of underwater vehicles. With these advances in position sensing, our ability to precisely control the hovering and low-speed trajectory of an underwater vehicle is limited principally by our understanding of the vehicle’s dynamics and dynamics of the bladed thrusters commonly used to actuate dynamically-positioned marine vehicles. So the dynamics of thrusters, are developed, and an appropriate mapping matrix dependent on the position and orientation of the thrusters on the vehicle, is used to calculate resultant forces and moments of the thrusters on the center of gravity of the vehicle. It should be noted that hull-propeller and propeller-propeller interactions are considered in the modeling too. Finally the results of the simulations, for an underwater vehicle equipped with one 2 DOFs manipulator, are presented and discussed in details.

2005 ◽  
Vol 128 (2) ◽  
pp. 119-132 ◽  
Author(s):  
Mohammad Khalaj Amir Hosseini ◽  
Omid Omidi ◽  
Ali Meghdari ◽  
Gholamreza Vossoughi

In this paper, modeling and simulation of an underwater vehicle equipped with manipulator arms, using a composite rigid body algorithm, will be discussed. Because of the increasing need for unmanned underwater vehicles (UUVs) in oil and gas projects in the Persian Gulf, for doing operations such as inspection of offshore jackets, subsea pipelines, and submarine cables, and also pre-installation survey and post-laid survey of submarine pipelines and cables, design and construction of “SROV” was developed in Sharif University of Technology, and at the design stage behavior of the underwater vehicles was studied. In this paper, an efficient dynamic simulation algorithm is developed for an UUV equipped with m manipulators so that each of them has N degrees of freedom. In addition to the effects of the mobile base, the various hydrodynamic forces exerted on these systems in an underwater environment are also incorporated into the simulation. The effects modeled in this work are added mass, viscous drag, fluid acceleration, and buoyancy forces. For drag forces, the emphasis here is on the modeling of the pressure drag. Recent advances in underwater position and velocity sensing enable real-time centimeter-precision position measurements of underwater vehicles. With these advances in position sensing, our ability to precisely control the hovering and low-speed trajectory of an underwater vehicle is limited principally by our understanding of the vehicle’s dynamics and the dynamics of the bladed thrusters commonly used to actuate dynamically positioned marine vehicles. So the dynamics of thrusters are developed and an appropriate mapping matrix dependent on the position and orientation of the thrusters on the vehicle is used to calculate resultant forces and moments of the thrusters on the center of gravity of the vehicle. It should be noted that hull-propeller and propeller-propeller interactions are considered in the modeling too. Finally, the results of the simulations, for an underwater vehicle equipped with 1 two degrees of freedom manipulator, are presented and discussed in detail.


Author(s):  
Manavendra Desai ◽  
Ruddhi Gokhale ◽  
Atanu Halder ◽  
Moble Benedict ◽  
Yin Lu Young

This paper investigates the novel concept of augmenting the maneuverability of underwater vehicles with cycloidal propellers. Cycloidal propellers have the potential of providing agile manoeuvring capabilities to an underwater vehicle such as enabling pure heave motion and spot turns. They will also enable the vehicle to surge in forward and backward directions with equal ease. Such manoeuvres are not possible with the more conventional screw propeller and control fin combinations. Moreover, cycloidal propellers can enable precise dynamic positioning in low speed applications like station-keeping, underwater surveying and maintenance, minesweeping and teaming activities. In this paper, manoeuvring capabilities of an underwater vehicle with conventional screw propeller and control fins only are compared with one augmented with cycloidal propellers. The cases considered include a turning circle manoeuvre, a low speed 180o turn and a low speed heave manoeuvre. A six degrees-of-freedom non-linear hydrodynamic motion prediction model was developed and validated. Simulation results demonstrated that compared to conventional propulsion systems, cycloidal propeller augmented underwater vehicles can be more swift and compact in low speed manoeuvres, making a case for further investigation into this concept.


Author(s):  
A. Meghdari ◽  
G. R. Vossoughi ◽  
M. Amir Hosseini

In this paper, an efficient dynamic simulation algorithm is developed for an Unmanned Underwater Vehicle (UUV) with a N degrees of freedom manipulator. In addition to the effects of mobile base, the various hydrodynamic forces exerted on these systems in an underwater environment are also incorporated into the simulation. The effects modeled in this work are added mass, viscous drag, fluid acceleration, and buoyancy forces. Also the dynamics of thrusters are developed, and an appropriate mapping matrix dependent on the position and orientation of the thrusters on the vehicle, is used to calculate resultant forces and moments of the thrusters on the center of gravity of the vehicle. It should be noted that hull-propeller and propeller-propeller interactions are considered in the modeling too. Finally the results of the simulations are presented.


Author(s):  
Signe Moe ◽  
Walter Caharija ◽  
Kristin Y. Pettersen ◽  
Ingrid Schjølberg

The use of autonomous marine vehicles, and especially autonomous underwater vehicles, is rapidly increasing within several fields of study. In particular, such vehicles can be applied for sea floor mapping, oceanography, environmental monitoring, inspection and maintenance of underwater structures (for instance within the oil and gas industry) and military purposes. They are also highly suitable for operations below ice-covered areas in the Arctic. However, there are still many challenges related to making such underwater vehicles autonomous. A fundamental task of an autonomous underwater vehicle vessel is to follow a general path in the presence of unknown ocean currents. There exist several results for underwater vehicles to follow a general path when no ocean currents are present [1] and to follow a geometrically simple path such as a straight line when ocean currents affect the vehicle [2, 3], but the problem of general path following in the presence of unknown ocean currents has not been solved yet. This paper presents a method to achieve this. The results are an extension of the results in [1], and introduce a virtual Serret-Frenet reference frame that is anchored in and propagates along the desired path. The closed-loop system consists of an ocean current observer, a guidance law, a controller and an update law to drive the Serret-Frenet frame along the path, and is shown to be asymptotically stable given that certain assumptions are fulfilled. This guarantees that the autonomous underwater vehicle will converge to the desired path and move along it with the desired velocity. Simulation results are presented to verify and illustrate the theoretical results.


Author(s):  
Sung Koh ◽  
Wankyun Chung

A Jacobian-based algorithm for motion planning for an underactuated system that is a rigid-body operated by two input-rotations is discussed in this paper. The rigid body undergoes a four-rotation fully-reversed (FR) sequence of rotations which consists of a series of initial two rotations about the axes of a coordinate frame attached to the rigid body and subsequent two rotations that undo the proceeding rotations. Due to the insufficient degrees of freedom of four-rotation FR sequences required to achieve all possible orientations, the rigid body cannot achieve some orientations. In order to best approximate these infeasible orientations, the Jacobian-based algorithm is implemented in the sense of least squares. As some orientations can never be attained by a single four-rotation FR sequence, two different four-rotation FR sequences are exploited alternately to ensure the convergence of the proposed algorithm. Assuming the orientation is supposed to be manipulated using three input-rotations, the switching-Jacobian algorithm proposed in this paper has significant practical importance for motion planning for aerospace and underwater vehicles maneuvered using only two input-rotations due to the failure of one of torque-generation mechanisms.


2010 ◽  
Vol 44 (2) ◽  
pp. 19-36 ◽  
Author(s):  
Bruno Ferreira ◽  
Aníbal Matos ◽  
Nuno Cruz ◽  
Miguel Pinto

AbstractIn this work, we address the modeling and control problems in the domain of underwater vehicles. We focus on a prototype of an autonomous underwater vehicle. Although the work presented here is applied to a particular vehicle with four controllable degrees of freedom, the method may be easily extended to several submerged bodies. In the engineering area, modeling of systems is done frequently, as it yields a mathematical translation of their behavior. Since models can become an important tool to solve problems related to its motion or even to the design of controllers, we obtain a model with six degrees of freedom for such a vehicle.Robust control of underwater vehicles is an area in which many efforts were applied over the last two decades. However, due to nonlinear dynamics, it may be hard to design robust controllers that yield the expected behavior, and there is no general procedure to develop them. Here, we propose an approach that combines nonlinear controllers based on the deduced model and on the Lyapunov theory to control the velocities of the vehicle with linear controllers that control the vehicle’s position. We derive control laws to perform several maneuvers, both in the vertical and the horizontal planes, in a decoupled way, which is made possible through the configuration of thrusters. Finally, we present realistic simulations and experimental results that validate the proposed approach in the definition of the control laws.


2018 ◽  
Vol 63 (2) ◽  
pp. 10-17
Author(s):  
Marek Dawidziuk ◽  
Adam Olejnik

Abstract The article presents the general construction of an underwater vehicle manipulator along with a discussion of the materials used in their construction. The types of drive systems used by the manipulator have been characterised, distinguishing their advantages and disadvantages. The functions of the manipulator are specified in relation to the activities performed by it. Moreover, the paper discusses the manipulator's degrees of freedom with the specification of the formula for their calculation. The basic types of end effectors are presented as well as an outline of the classification of manipulators in relation to the tasks carried out.


Author(s):  
Eleni Kelasidi ◽  
Gard Elgenes ◽  
Henrik Kilvær

Nowadays different types of unmanned underwater vehicles (UUVs), such as remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs), are widely used for sub-sea inspection, maintenance, and repair (IMR) operations in the oil and gas industry, archaeology, oceanography and marine biology. Also, lately, the development of underwater snake robots (USRs) shows promising results towards extending the capabilities of conventional UUVs. The slender and multi-articulated body of USRs allows for operation in tight spaces where other traditional UUVs are incapable of operating. However, the mathematical model of USRs is more challenging compared to models of ROVs and AUVs, because of its multi-articulated body. It is important to develop accurate models for control design and analysis, to ensure the desired behaviour and to precisely investigate the locomotion efficiency. Modelling the hydrodynamics poses the major challenge since it includes complex and non-linear hydrodynamic effects. The existing analytical models for USRs consider theoretical values for the fluid coefficients and thus they only provide a rough prediction of the effects of hydrodynamics on swimming robots. In order to obtain an accurate prediction of the hydrodynamic forces acting on the links of the USRs, it is necessary to obtain the fluid coefficients experimentally. This paper determines the drag and added mass co-efficients of a general planar model of USRs. In particular, this paper presents methods for identifying fluid parameters based on both computational fluid dynamic (CFD) simulations and several experimental approaches. Additionally, in this paper, we investigate variations of the drag force modelling, providing more accurate representations of the hydrodynamic drag forces. The obtained fluid coefficients are compared to the existing estimates of fluid coefficients for a general model of USRs.


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