Skip to main content

Über dieses Buch

Dynamics and Control of Mechanical Systems in Offshore Engineering is a comprehensive treatment of marine mechanical systems (MMS) involved in processes of great importance such as oil drilling and mineral recovery. Ranging from nonlinear dynamic modeling and stability analysis of flexible riser systems, through advanced control design for an installation system with a single rigid payload attached by thrusters, to robust adaptive control for mooring systems, it is an authoritative reference on the dynamics and control of MMS. Readers will gain not only a complete picture of MMS at the system level, but also a better understanding of the technical considerations involved and solutions to problems that commonly arise from dealing with them.

The text provides:

· a complete framework of dynamical analysis and control design for marine mechanical systems;

· new results on the dynamical analysis of riser, mooring and installation systems together with a general modeling method for a class of MMS;

· a general method and strategy for realizing the control objectives of marine systems with guaranteed stability the effectiveness of which is illustrated by extensive numerical simulation; and

· approximation-based control schemes using neural networks for installation of subsea structures with attached thrusters in the presence of time-varying environmental disturbances and parametric uncertainties.

Most of the results presented are analytical with repeatable design algorithms with proven closed-loop stability and performance analysis of the proposed controllers is rigorous and detailed.

Dynamics and Control of Mechanical Systems in Offshore Engineering is primarily intended for researchers and engineers in the system and control community, but graduate students studying control and marine engineering will also find it a useful resource as will practitioners working on the design, running or maintenance of offshore platforms.



Chapter 1. Introduction

Chapter 1 introduces the system description, background, and motivation of the study and presents several general concepts and fundamental observations.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 2. Preliminaries

Chapter 2 presents several lemmas and properties used in the subsequent development and derivations of the dynamical models, and further stability analysis for the marine mechanical structures.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 3. Dynamic Load Positioning

In Chap. 3, positioning control in the horizontal plane is investigated for the installation of subsea systems, with thrusters attached, under time-varying irrotational ocean current, when the payload is near to the seabed. Backstepping, in combination with adaptive feedback approximation techniques, is employed in the design of the control, with the option of high-gain observer for output feedback control. The stability of the design is demonstrated through Lyapunov analysis where the semiglobal uniform boundedness of the closed-loop signals is guaranteed. The proposed adaptive neural control is able to capture the dominant dynamic behaviors without exact information on the hydrodynamic coefficients of the structure and current measurements.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 4. Installation System with Constraints

In Chap. 4, the model of the coupled crane-cable-payload with nonuniform parameters is presented. Positioning control is derived for the coupled system with uniform parameters using barrier Lyapunov functions. Through Lyapunov analysis, it is shown that the coupled crane–payload flexible system is stable under the control action, the physical limits from operations planning and safety specifications are not transgressed, and positioning of crane and payload is achieved. A stabilizing boundary control is proposed for the coupled system with nonuniform parameters. Rigorous Lyapunov stability analysis is carried out and the uniform boundedness of the system is shown under the proposed control. Finally, the performance of the proposed control is given through numerical simulations.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 5. Marine Installation System

In Chap. 5, robust adaptive boundary control of a marine installation system is developed to position the subsea payload to the desired set-point and suppress the cable’s vibration. The flexible cable coupled with vessel and payload dynamics is described by a distributed-parameter system with one partial differential equation (PDE) and two ordinary differential equations (ODEs). Boundary control is proposed at the top and bottom boundaries of the cable based on the Lyapunov direct method. Considering the system parametric uncertainties and the unknown ocean disturbances, the developed adaptive boundary control schemes achieve uniform boundedness of the steady-state error between the boundary payload and the desired position. The control performance of the closed-loop system is guaranteed by suitably choosing the design parameters.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 6. Adaptive Control of Thruster-Assisted Single-Point Mooring Systems

Chapter 6 is dedicated to the control problem of a thruster-assisted single-point mooring system in the presence of uncertainties and unknown backlash-like hysteresis nonlinearities. Using the backstepping technique and Lyapunov synthesis and employing neural networks (NNs) to approximate the unknown nonlinear functions, robust adaptive backstepping control is developed for the full-state feedback case. Subsequently, in order to overcome the measure difficulty in the vessel velocity vector, a high-order NN-based observer is constructed to estimate the unmeasurable state vector. It is shown that the proposed observer has an excellent estimation performance in spite of the existence of uncertainties and unknown backlash-like hysteresis nonlinearities. Based on this observer, robust adaptive output feedback control is developed via backstepping design. Under the proposed control, the semiglobal uniform boundedness of all the signals in the closed-loop systems is guaranteed for both full-state and output feedback cases.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 7. Coupled Nonlinear Flexible Marine Riser

In Chap. 7, boundary control for a coupled nonlinear flexible marine riser with two actuators in transverse and longitudinal directions is developed to reduce the riser’s vibrations. The dynamic behavior of the flexible riser is represented by a distributed-parameter system (DPS) model with partial differential equations (PDEs), and the control is applied at the top boundary of the riser based on Lyapunov’s direct method to suppress the riser’s vibrations. With the proposed boundary control, the uniform boundedness under ocean current disturbances and exponential stability under free vibration condition is achieved. The proposed control is independent of system parameters, which ensures the robustness of the system to variations in parameters.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 8. Flexible Marine Riser with Vessel Dynamics

Chapter 8 studies the modeling and control of a flexible marine riser with the vessel dynamics. Both the dynamics of the vessel and the vibration of the riser are considered in the dynamic analysis, which make the system more difficult to control. Boundary control is proposed at the top boundary of the riser to suppress the riser’s vibration. Adaptive control is designed when the system parametric uncertainties exist. Employing the Lyapunov direct method, the states of the system are proven to be uniformly ultimately bounded. The state of the system will converge to a small neighborhood of zero by appropriately choosing the design parameters. The design is based on the PDEs of the system, thus avoiding some drawbacks associated with the traditional truncated-model-based design approaches.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 9. Structural Analysis and Riser Operations (Geoff Lyons and Minoo Patel)

Chapter 9 serves as an industrial case study in this book. This chapter investigates the structural analysis and the riser operations of fixed and floating offshore structures using pipe connections between surface facilities and seabed as well as pipes laying on or below the seabed for transportation of oil and gas. The analysis of vertical marine risers under the influences of both internal and external forces is described. Four configurations of the marine risers are introduced, including free-handing mode, connected mode, operational mode, and nonoperational but connected mode. A marine riser can be maintained in an operable condition by ensuring that the lower ball joint angle remains below about 4 degrees. Three operating procedures are given to bring the angle down. The marine riser monitoring system provides information on the behaviors of the platform and the marine riser, and comparisons can be made with previous results for evaluating the projected fatigue life of the riser. BPP-RMS, an example of the comprehensive Riser Management System (RMS) for riser maintenance and inspection, is presented. BPP-RMS is an on-board riser operation management system that provides real-time guidance for carrying out connected and disconnected mode drilling riser operations on board a vessel.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo

Chapter 10. Conclusions

Chapter 10, the last chapter, makes conclusions on this book.
Wei He, Shuzhi Sam Ge, Bernard Voon Ee How, Yoo Sang Choo


Weitere Informationen