Authors: Galeazzi, Roberto; Blanke, Mogens

Abstract: When parametric resonance occurs on a ship, large roll motion develops rapidly and severe damage on cargo is likely. Some vessels have even capsized in moderate seas for reasons believed to be parametric resonance. This paper revisits the analysis of parametric resonance and assess the possibility to dynamically modify the instability region where parametric roll can occur. It is shown how a control strategy for roll stabilization could be modi?ed to change a bifurcation in roll motion and stabilize the motion, even after parametric resonance has started. The paper addresses issues of achievable performance and demonstrates the approach on a yaw-sway-roll-surge model of a containership.

Keywords: parametric resonance,parametric roll,ship motion control

Identifier: 10.3182/20070919-3-HR-3904.00010

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Polyakov, Konstantin Y.; Rosenwasser, Efim N.; Korte, Holger; Lampe, Bernhard P.

Abstract: The problem of optimal digital controller design is considered for sampled-data systems under typical sector-type restrictions imposed on location of the closed loop poles. The set of admissible characteristic polynomials having a fixed degree is parameterized in terms of a real vector with elements in [0; 1]. This idea makes it possible to use a two-level optimization procedure based on global optimization algorithms, which is sometimes more attractive than a local search.

Keywords: sampled-data control systems,pole assignment,parametrization,optimal control

Identifier: 10.3182/20070919-3-HR-3904.00046

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Lum, Kai-Yew; Zhang, Zi-Jun; Png, Eng-Kwee

Abstract: A passivation approach is proposed for the guidance and control of under-actuated marine craft, which integrates trajectory planning and dynamic tasking in a single formulation. Trajectory and velocity requirements are specified through the design of a manifold in the phase space, and convergence proof is based on the invariant set theorem. Two design cases, path tracking and course keeping, are presented in detail.

Keywords: control system design,marine systems,passive compensation,robustness,trajectory planning

Identifier: 10.3182/20070919-3-HR-3904.00027

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Bibuli, Marco; Caccia, Massimo; Lapierre, Lionel

Abstract: This paper addresses the problem of path-following in two-dimensional space, for underactuated surface autonomous robots, defining a set of guidance laws either at kinematic and dynamic level. The proposed nonlinear Lyapunov-based control law yields convergence of the path following error coordinates to zero. Furthermore, the introduction of a dynamic for the target to be followed on the path, removes singularity behaviors present in other guidance algorithms proposed in the literature. Dynamic of the vehicle is then taken into account, applying the Backstepping technique. Some heuristic approaches are then proposed to face the problem of speed of advance adaptation based on path curvature measure and steering action prediction. Finally a set of experimental results of all the proposed guidance laws are presented.

Keywords: path-following,non-linear control,backstepping

Identifier: 10.3182/20070919-3-HR-3904.00015

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Almeida, João; Silvestre, Carlos; Pascoal, António

Abstract: This paper addresses the problem of driving a surface vessel along a desired spatial path. A nonlinear adaptive controller is designed that yields convergence of the trajectories of the closed loop system to the path in the presence of constant unknown ocean currents and parametric model uncertainty. Controller design builds on Lyapunov based techniques and backstepping. The controller derived implicitly compensates for the effect of the ocean current without the need for direct measurements of its velocity. An illustrative simulation example is presented and discussed.

Keywords: path-following,autonomous vehicles,nonlinear theory,adaptive control

Identifier: 10.3182/20070919-3-HR-3904.00006

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Pivano, Luca; Whitcomb, Louis L.; Johansen, Tor Arne; Fossen, Thor Inge

Abstract: In this paper a recently reported four-quadrant nonlinear thrust controller for marine propellers is applied to the velocity control of an underwater vehicle. The controller, designed for fixed pitch electrically driven propellers, is based on a shaft speed control and employs an estimate of the propeller torque loss. A simulation study is performed in order to compare the presented approach with the conventional shaft speed and torque propeller controllers.

Keywords: underwater vehicle,marine propulsion,thrust control,state estimation,nonlinear vehicle control

Identifier: 10.3182/20070919-3-HR-3904.00039

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Horgan, Jonathan; Toal, Daniel; Ridao, Pere; Garcia, Rafael

Abstract: This paper proposes a real-time navigation 000system for an AUV that takes advantage of the complementary performance of a sensor suite including a DVL, a compass, a depth sensor and altimeter sensors with a feature based motion estimator using vision. To allow for real-time performance of the vision based motion estimator a simple but fast correlation algorithm is used for feature matching. The compass and the depth sensors are used to bound the drift of the heading and depth estimations respectively. The altimeter is required in order to translate the feature displacements measured from the images into the metric displacements of the robot. While the robot must rely on DVL navigation above a certain altitude where vision is useless, DVL measurements can be complemented with higher frequency accurate motion estimates from the vision system when navigating close to the seafloor.

Keywords: marine robotics,robot vision,Kalman filtering,robot navigation

Identifier: 10.3182/20070919-3-HR-3904.00065

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Horner, Douglas; Yakimenko, Oleg

Abstract: Improvements in high resolution small forward looking sonar (FLS) and computer processing have made it possible to develop an obstacle avoidance system (OAS) for small diameter Autonomous Underwater Vehicles (AUV). An AUV with such a system can maneuver around unanticipated obstacles that may be proud of the ocean floor. This ability can prevent serious damage to the vehicle or the environment. This paper discusses developments in control and computer vision techniques of an OAS designed to vertically avoid obstacles found on the ocean floor. Results are presented from recent in-water testing.

Keywords: obstacle avoidance,optimal control,navigation,obstacle detection

Identifier: 10.3182/20070919-3-HR-3904.00005

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Luque, Juan C. Cutipa; Donha, Decio Crisol

Abstract: Nowadays the control of under-actuated underwater vehicles with coupled dynamics is a research of major interest, not only but mainly due to the large number of applications in the offshore industry. In a former work, authors developed a controller exhibiting desired robustness features, which unfortunately presented a poor performance in tracking activities. To tackle this problem, a two degree of freedom robust controller using an H∞ mixed sensitivity approach as before was then developed. A Light of Sight (LOS) guidance control law was also added to face the impossibility of a straight control of position variables within the used optimal approach. Simulation results of an Underwater vehicle with six degree of freedom using the centralized controller show now strong robustness and a very good performance.

Keywords: robust control,guidance,underwater vehicles

Identifier: 10.3182/20070919-3-HR-3904.00062

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Holden, Christian; Pettersen, Kristin Y.

Abstract: This work deals with the global exponential stabilization of the origin of 6- DOF AUVs. The control law is time-invariant and continuous. Unit quaternions are used as representation of orientation, preventing problems caused by the Euler singularity. No simplifications are made in kinematics or dynamics. A strict Lyapunov function is also developed for the controlled system. The system is proven to be ISS with respect to disturbances. This work also presents some highly useful results regarding unit quaternions, and presents a global diffeomorphism for position that eases controller design. Results are verified with simulations on the HUGIN 1000 AUV.

Keywords: nonlinear control,backstepping,Lyapunov theory,quaternions

Identifier: 10.3182/20070919-3-HR-3904.00060

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Stipanov, Marin; Miskovic, Nikola; Vukic, Zoran; Barisic, Matko

Abstract: The Automarine Module is a simple cost effective method for transforming underwater remotely operated vehicles (ROVs) into autonomous underwater vehicles (AUVs), with minimum development time, and with no ROV circuit alteration. This paper presents architecture of autonomization of the VideoRay Pro II ROV together with its technical specifications. The paper also presents a procedure for open-loop identification of the nonlinear yaw model. Analytical expressions that are used for model identification are also provided.

Keywords: underwater vehicle,AUV,architecture,identification

Identifier: 10.3182/20070919-3-HR-3904.00032

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Komar, Ivan; Antonic, Radovan; Matic, Petar

Abstract: The exhaust emissions from large marine diesel engines on ocean going vessels contains among other pollutants a significant amount of Nitrogen Oxides (NOx) wich are the main byproduct of combustion and they contribute to acid rain as well as the formation of harmful ground-level ozone and photochemical smog. The manufacturers of the marine vessel engines and the shipbuilders have responded to the demands to reduce vessel emissions by improving the operation of the engines and by incorporating emissions control technologies in the design of new vessels. Selective Catalytic Reduction (SCR), fuel emulsions, water injection systems and a number of engine modifications are a sample of the technologies being employed. The challenge is to control NOx emissions without increasing fuel consumption and smoke. An SCR (Selective Catalytic Reduction) unit is an effective means of conditioning the exhaust gas after the combustion process for reducing NOx already formed in the combustion process. The process essentially involves injecting ammonia in the exhaust stream and in the presence of a catalyst the NOx reacts with the ammonia and forms water vapor and nitrogen This paper describes method to remove nitrogen oxides from exhaust gas of the slow speed marine diesel propulsion engine B&W-5L90MC using selective catalytic reduction (SCR). The efficiency of the SCR system was tested on engine room full mission simulator Kongsberg ERS-L11 MAN B&W-5L90MC-VLCC Version MC90-IV which is installed on Faculty of Maritime studies in Split. The results are illustrated by figures and graphs which shows a 95% NOx reduction in exhaust gas afer has been treated trought SCR reactor.

Keywords: marine diesel engine,exhaust emissions,nitrogen oxides,selective catalytic reduction (SCR)

Identifier: 10.3182/20070919-3-HR-3904.00054

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Zwierzewicz, Zenon

Abstract: The paper is concerned with the problem of adaptive ship track-keeping system control synthesis. It is assumed that a nonlinear ship dynamics (model structure) is (partially) unknown so it has to be reconstructed. To this end it has been proven that proportional state feedback plus adaptation via functional approximators are able to assure its asymptotic stability. This form of controller permits on-line compensation of unknown model nonlinearities which leads to satisfactory tracking performance. An interesting feature of the system is that the whole process control is performed without requisite asymptotic convergence of approximator parameters to the postulated 'true' values. The system's performance, which has been tested via Matlab/Simulink simulations, confirms the efficiency of the adopted solution technique.

Keywords: marine vehicle control,adaptive systems,intelligent control

Identifier: 10.3182/20070919-3-HR-3904.00017

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Tiano, Antonio; Lajic, Zoran; Zirilli, Antonio

Abstract: This paper discusses the applicability of monitoring systems for improving ship control. After introducing some critical issues in the area of ship motion control, an analysis is presented concerning the choice of different architecture and algorithms with particular reference to the applicability of new methods capable to implement robustnessand adaptivity features and to the software requirements for building up advanced ship monitoring and control systems. An examples of ship monitoring and control system actually under development at the Department of Information and Systems of the University of Pavia are presented.

Keywords: ship control,soft sensing,uncertain dynamic systems,estimation algorithms

Identifier: 10.3182/20070919-3-HR-3904.00028

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Anonsen, Kjetil Bergh; Hallingstad, Oddvar

Abstract: Precise underwater navigation is crucial in a number of marine applications. Navigation of most autonomous underwater vehicles (AUVs) is based on inertial navigation. Such navigation systems drift off with time and external fixes are needed. This paper concentrates on terrain-based navigation, where position fixes are found by comparing measurements with a prior map. Nonlinear Bayesian methods like point mass and particle filters are often used for this problem. Such methods are often computationally demanding. The sigma point Kalman filter (or unscented Kalman filter) is a nonlinear filter that does not resort to local linearizations, representing the probability densities using a few deterministically chosen sigma points. The sigma point Kalman filter is not as computationally demanding as the aforementioned methods, and using real AUV data, the accuracies obtained are comparable to those of the point mass and particle filters.

Keywords: navigation systems,estimation algorithms,Kalman filters,autonomous vehicles,marine systems,state-space models

Identifier: 10.3182/20070919-3-HR-3904.00020

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Kuzmanic, Ivica; Vujovic, Igor; Anotnic, Radovan; Kulenovic, Zlatan

Abstract: Many computer, machine or robot vision applications need increased resolution of images. Very actual are security applications and vision for mobile automatic vehicles and robots. The application of superresolution is interesting in airborne, land and maritime applications. Adverse illumination and noise image are particular challenge. Superresolution algorithm based on motion field is developed in the article. It is applicable on the single image. For real time applications, the time of execution ranges from 7.6 fps up to 34 fps in the experimental setup (Matlab, Windows, etc). There is still a lot of place for improvements and further research.

Keywords: robot vision,computer vision,human-machine interface,digital images,digital filters,image processing

Identifier: 10.3182/20070919-3-HR-3904.00069

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Rustad, Anne M.; Sørensen, Asgeir J.; Larsen, Carl M.

Abstract: For a riser array in deep waters interference between individual risers exposed to strong ocean current and/or large TLP motions is of concern. The lateral deflections are likely to be large, and the risers may experience collision with fatigue or surface damage as a consequence. In this paper a supervisory switched controller for marine risers using a riser tensioner system is proposed. A case study shows how the controller structure and parameters change according to the environmental conditions and the riser behavior.

Keywords: riser collision,supervisory switched control,simulation

Identifier: 10.3182/20070919-3-HR-3904.00036

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Dyda, A. A.; Lubimov, E. V.; Sheykhot, A. K.

Abstract: This paper deals with the problem of the automation of design procedures for nonlinear control systems. As an example the procedure has been realized for the well-known technique consisting of the exact linearization via nonlinear feedback. The developed software achieves the synthesis of control laws in symbolical form that is convenient for further analysis, modeling, and practical implementation of the system. Examples of the software application to underwater vehicle and robot manipulator are given and discussed.

Keywords: nonlinear control,algorithms,software engineering,linearization,manipulators

Identifier: 10.3182/20070919-3-HR-3904.00044

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Ruth, Eivind; Sørensen, Asgeir J.; Perez, Tristan

Abstract: In this paper, a method of thrust allocation based on a linearly constrained quadratic cost function capable of handling rotating azimuths is presented. The problem formulation accounts for magnitude and rate constraints on both thruster forces and azimuth angles. The advantage of this formulation is that the solution can be found with a finite number of iterations for each time step. Experiments with a model ship are used to validate the thrust allocation system.

Keywords: optimization,propulsion control,quadratic programming,thrust allocation

Identifier: 10.3182/20070919-3-HR-3904.00059

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Roberts, Geoff N.

Abstract: Sperry and Minorski are names synonymous with the development of the first steering autopilots and it is well known that their pioneering work and seminal publications led to the introduction of the three-term or proportional-integral-derivative (PID) controller for automatic ship steering. Despite the efforts and enthusiasm of numerous researchers, from all areas of control engineering, to persuade industry to adopt more sophisticated controller designs, PID controllers remain the industry preference and industry standard for automatic control systems. The paper sets the scene with a review of the early developments of automatic control systems for ship steering, which led to Sperry's automatic pilot. This is followed by an overview of developments in roll stabilisation; integrated ship steering and roll stabilisation; unmanned underwater vehicles and unmanned surface vessels. Consideration of over 700 papers presented the twelve conferences and workshops sponsored by the IFAC Technical Committee on Marine Systems in the period 1992 to 2007 is used to track recent trends in marine control systems and as the basis for some thoughts on possible future directions for the marine control community.

Keywords: ship steering,ship roll stabilization,unmanned marine vehicles

Identifier: 10.3182/20070919-3-HR-3904.00056

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007

Authors: Morgado, M.; Oliveira, P.; Silvestre, C.; Vasconcelos, J. F.

Abstract: This paper presents a Vehicle Dynamics (VD) aiding technique to enhance position, velocity, and attitude error estimation in low-cost Inertial Navigation Systems (INS), with application to Underwater Vehicles (UV). The VD model is directly embedded in an Extended Kalman Filter (EKF) and provides specific information about the rigid body tridimensional motion unavailable from the INS computations, thus allowing for a comprehensive improvement of the overall navigation system performance. A tightly-coupled inverted USBL is also adopted to enhance position and attitude estimation using range measurements to transponders in the vehicle's mission area. The overall Navigation System accuracy improvement is assessed in simulation using a nonlinear model of the Infante UV.

Keywords: inertial navigation,sensor fusion,vehicle dynamics

Identifier: 10.3182/20070919-3-HR-3904.00021

Conference: 7th IFAC Conference on Control Applications in Marine Systems (2007)

Location: Grand Hotel Elaphusa, Croatia

Start Date: Wed Sep 19 2007 - End Date: Fri Sep 21 2007