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Modelling and Control of ASV acting as communication node for deep-sea applications
Abstract
This paper describes the basic characteristics of a six degrees of freedom dynamic model of an innovative ocean-going unmanned surface vehicle. The model is used in an explicit and implicit way to ensure the operation of the autonomously acting vehicle, which serves as communication node between surface and underwater parts of a complex deep-sea monitoring system. In practice, it is a cumbersome task to identify the unknown parameters of such nonlinear models, due to strong couplings of the motion variables, measurement noise and unknown disturbances. In order to parameterize the models, special maneuvers have been carried out to decouple the motions and identify the corresponding parameters. Properties of the acoustic communication has been taken into account when designing the unmanned surface vehicle. Finally, it has been built as a shallow submerged vehicle with water surface-piercing towers to assure a reliable acoustic communication and positioning link up to a depth of 6.000 meters even in heavy sea states. As the vehicle motion has a decisive impact on its operation, the basic characteristics of the motion of the vehicle in waves have been investigated from the quasi-static case using potential theory to simpler dynamic models for the specific degree of freedom. Further, these models are used to design feed forward and feedback controller to ensure the autonomous vehicle operation. The paper concludes with a performance evaluation of the proposed controllers based on data recorded at field trials.
... Mainly in the research community, specialized vehicles are used for which specific nonlinear coupled models has been parameterized, e.g. [2], [3], [4]. The parameterization of such nonlinear coupled models demands high effort, which is limited for conventional USV. ...
... Sensors have been attached to the vessels and in some cases towed [1]. ASVs have also been used as communication nodes for UUVs and AUVs [4]. Hull designs of ASVs are similar to other surface vessels, and are categorized into four different types: rigid inflatable hulls, single hulls, catamarans and trimarans. ...
Kleinere unbemannte, autonom agierende Überwasserfahrzeuge (Unmanned Surface Vehicles/USV) mit Abmessungen im Bereich einiger Meter werden zunehmend zur Erfassung ozeanografischer Daten, für Rettungsaufgaben, zur Ausführung von Suchaufgaben auf dem Meeresboden und als Kommunikationssystem zu Unterwasserstationen und -fahrzeugen benötigt. Ein wesentlicher Einsatzbereich stellt der Meeresraum im Tiefenbereich zwischen der Küstenlinie und 10 m Wassertiefe dar, der durch größere Forschungs- und Vermessungsschiffe nicht erfasst werden kann. Nach einer Darstellung der Entwicklung von USV seit der Mitte der 90er Jahre, wird als Fallbeispiel auf den Prototyp Messdelphin (MESSIN) näher eingegangen, der im Rahmen eines an der Universität Rostock mit Kooperationspartnern bearbeiteten Forschungsprojekts entwickelt wurde. Die schiffbautechnisch/hydrodynamischen und elektrisch/elektronischen Komponenten sowie das hierarchische Steuerungssystem des MESSIN werden behandelt. Eine aktuelle, modernisierte Version des MESSIN wird vorgestellt. Umfangreiche Ergebnisse zur Modellbildung und Identifikation sowie zum automatischen Bahnführungssystem demonstrieren die guten Manövriereigenschaften und die Performance des MESSIN. Abschließend wird ein Überblick zu den vielfältigen Messkampagnen des MESSIN in einem Zeitraum von nahezu 20 Jahren gegeben.
Nach einer Darstellung der Grundschritte und -struktur der experimentellen Systemidentifikation (Abschn. 6.2 und 6.3) erfolgt eine Klassifikation von Identifikationsverfahren in Abhängigkeit der verwendeten Testsignale (Abschn. 6.3). Es wird ein Identifikationsalgorithmus für die Ermittlung der Steuerparameter des IT1-Kursmodells aus den determinierten Sprungantworttests des Kurses und der Gier-Drehrate beim Anschwenken eines Drehkreises abgeleitet (Abschn. 6.4), der auf eine größere Zahl von seegehenden Fahrzeugen angewendet wird (Kap. 6.5). Tendenzen der Veränderung der Steuerparameter in Abhängigkeit von Fahrzeuggröße, Geschwindigkeit und Ruderwinkel werden abgeleitet. Statistische Parameterschätzverfahren haben sich zu einem sehr ausgedehnten Fach- und Forschungsgebiet für die Identifikation stochastisch gestörter Prozesses entwickelt, sodass hier für maritime Prozesse die Fokussierung auf die Grundlagen und die Anwendung einiger wichtiger Parameterschätzmethoden erfolgt (Abschn. 6.6). An synthetischen, gestörten Daten und Borddaten des Ausbildungsschiffs „Störtebeker“ werden die Erwartungstreue und Störanfälligkeit der RLS-, RELS- und RIV-Parameterschätzverfahren getestet (Abschn. 6.7 und 6.8). Das IT1-Kursmodell des USV Messdelphin (MESSIN) wird mittels der PEM-Schätzmethode identifiziert (Abschn. 6.9). Für Containerschiffe des Typs Warnow CS 1400 erfolgt auf der Grundlage von Borddaten die Identifizierung von Kurs- und Bahnabstandmodellen mittels des Maximum-Likelihood-Verfahrens (Kap. 6.10) und des RLS-Verfahrens (Kap. 6.11). Im Zusammenhang mit der Manöverregelung wird auf notwendige Testmanöver zur Parametrierung des parametervariablen Modells für die Manöverfahrt (Abschn. 12) und auf die Bedatung des parametervariablen Modells (Abschn. 13) eingegangen.
A major advantage of Autonomous Underwater Vehicles (AUVs) is that it is possible to operate a greater number of them simultaneously thanks to their autonomous and cable-less characteristics. However, the more AUVs are operating at the same time, the more difficult it becomes to control them. One of the solutions to this problem is to use an Autonomous Surface Vehicle (ASV) and this allows the mother ship to focus on ASV operations and emergency response.
In 2017, National Maritime Research Institute (NMRI) developed an ASV for AUV control and operated it with multiple AUVs for a seafloor resources survey. In this operation, the ASV collected data on the AUV's status and transmitted it in radio communication, making it possible the mother ship to focus on launch and recovery operations. In this paper, we introduce the results of the ASV operation to control the AUVs along with the development and sea trials of the ASV.
In this paper we present a multiphysics simulation model of Halcyon, an autonomous unmanned surface vehicle (USV). The simulation model presented in this paper has been developed to rapidly progress the design, development and validation of Halcyon’s autonomy management system, particularly in challenging sea conditions. Using simulation for this purpose enables extensive testing across the full environmental operating envelope of the vessel, hence greatly reducing the need for real-world sea-trials. The simulator is comprised of a novel and comprehensive sea-surface wave environment model, a six degree of freedom nonlinear unified seakeeping and manoeuvring boat dynamics model, an actuation dynamics model, an autopilot and an interface with an autonomy management system. Results are presented that show good agreement between real-world and simulated sea-trials data.
Autonomous marine vehicles are mostly associated with complex automation and control algorithms, nevertheless the naval engineering design of such vehicles is a challenging task, too. In addition to the classical issues like drag reduction, propulsion optimization and strength calculations, specific features have to be taken into consideration. Noteworthy are the energy supply concept and the precise ballasting for stability and hy-drodynamics. To fulfill the versatile requirements of the unmanned surface vehicle a shallow submerged body, with a water surface-piercing tower is the concept of choice. However this design implies many new issues. The intended operation period of up to one week at open sea requires a robust system and a reliable power supply. These and other challenging problems make the design of such a vehicle to an exciting and complex task. Zusammenfassung Denkt man bei autonomen Wasserfahrzeugen zunächst an komplexe Steuerungs-und Regelungsalgorithmen, so ist jedoch auch der schiffbauliche Entwurf eines unbemannten Fahrzeuges eine anspruchsvolle Aufgabe. Neben den klassischen Fragestellungen wie Widerstandsreduktion, Antriebs-und Energieversorgungskonzept oder der Festig-keit müssen zum Beispiel die Ballastierung und Hydrostatik sowie die Umströmung einzelner Bauteile aus einem neuen Blickwinkel betrachtet werden. Die Auswahl eines flachgetauchten Strömungskörpers, mit einem die Was-seroberfläche durchstoßenden Turm, vereinfacht zwar die Erfüllung einzelner Anforderungen, wirft jedoch auch viele neue Probleme auf. Im speziellen Fall wurden durch die angestrebte Einsatzdauer von bis zu einer Woche auf hoher See eine weitere Randbedingungen definiert, die sich besonders auf die Robustheit und die Energieversor-gung auswirkten. Diese und weitere anspruchsvolle Problemstellungen machen den Entwurf eines solchen Fahr-zeugs zu einer spannenden und komplexen Aufgabe.
The impact of control system design on ship performance has been significant in different applications of ship motion control: course keeping, station keeping, roll stabilisation and vertical motion/riding control, diving, path following, etc. This monograph introduces ship motion control by studying the particular problems of control system design for course autopilots with rudder roll stabilisation and combined rudder–fin stabilisers. Ship Motion Control revisits the ingredients that make these control designs challenging and proposes a contemporary control system design approach to meet that challenge.
The key ingredients for a successful ship motion control system design are:
• appropriate mathematical models of the ship and the disturbances;
• understanding of how performance will be assessed;
• knowledge of fundamental limitations that may prevent designs from achieving the desired performance.
The book is organised in four parts, the first three dealing with each of these and the fourth part addressing control system design.
Specific topics covered include:
• modelling and simulation of ocean waves;
• ship dynamics;
• models of actuators;
• ship roll stabilisation devices;
• ship motion performance;
• analysis of fundamental limitations for stabiliser control system design;
• constrained control design via optimisation;
• autopilot design using optimal control;
• wave filtering;
• control system design for autopilots with rudder roll stabilisation;
• control system design for integrated rudder-fin stabiliser.
Ship Motion Control will be of interest not only to the practising marine engineer but to the academic engaged in research into this important control problem, even if new to the area. It will also be an ideal source of reference for students and tutors involved with marine and control engineering courses.
Advances in Industrial Control aims to report and encourage the transfer of technology in control engineering. The rapid development of control technology has an impact on all areas of the control discipline. The series offers an opportunity for researchers to present an extended exposition of new work in all aspects of industrial control.
Autonomous surface craft have been developed in particular for marine research and surveying exploration as well as for the rescue of human life at sea. To provide a rescue vehicle, an autonomous Rescue Dolphin was developed to rescue people in distress. The rescue system automatically triggers the alarm to the ship's management in case of 'man overboard', independently of ship manoeuvres. It moves fast towards the distressed person, and safeguards the distressed person until recovery by ship. The development of the unmanned autonomous surface vehicle Measuring Dolphin was carried out within the framework of the German cooperation project MESSIN. The main task of the project MESSIN consisted of the development and the testing of a prototype of the autonomous surface vehicle Measuring Dolphin which could be applied with high accuracy of positioning and track guidance and under shallow water conditions as a carrier of measuring devices. Fields of application include depth surveying, current and current profile measuring in port entrances and rivers, sediment research, extraction of samples for biological investigations and measuring in drinking water areas.
A recently proposed Integral Line-of-Sight (ILOS) guidance law is applied to an underactuated Unmanned Semi-Submersible Vehicle (USSV) for path following of straight lines. Derived from the popular Line-of-Sight guidance, the ILOS methods adds integral action to increase robustness with respect to environmental disturbances such as sea currents, wind and waves that unavoidably affect maritime operations. Integral action makes the vehicle sideslip and hence compensate for the disturbances acting in the underactuated sway direction. Furthermore, the integrator of the ILOS implemented in this paper has embodied, analytically derived, anti-windup properties. It is shown that even if an accurate model of the vessel dynamics is not available, a simple kinematic model and a few test runs give enough information to correctly choose the guidance law parameters. Data from sea trials are presented to verify the ILOS theory and give an experimentally based understanding of the behavior of the USSV when different look-ahead distances and integral gains are used.
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.
A recently proposed Integral Line-of-Sight (ILOS) guidance law is applied to an underactuated Unmanned Semi-Submersible Vehicle (USSV) for path following of straight lines. Derived from the popular Line-of-Sight guidance, the ILOS methods adds integral action to increase robustness with respect to environmental disturbances such as sea currents, wind and waves that unavoidably affect maritime operations. Integral action makes the vehicle sideslip and hence compensate for the disturbances acting in the underactuated sway direction. Furthermore, the integrator of the ILOS implemented in this paper has embodied, analytically derived, anti-windup properties. It is shown that even if an accurate model of the vessel dynamics is not available, a simple kinematic model and a few test runs give enough information to correctly choose the guidance law parameters. Data from sea trials are presented to verify the ILOS theory and give an experimentally based understanding of the behavior of the USSV when different look-ahead distances and integral gains are used.
This paper presents the joint research project “SMIS” with focus on the requirements and the design of the seabed station. A major issue for all autonomous subsea systems is the problem of limited battery capacity due to design boundary conditions. SMIS counteracts this by deploying an autonomous power-carrying vehicle, similar to a mobile petrol station, to extend the operation time for the AUVs.
The demands of the autonomous seabed station include the unguided submerge through 6000 m water column, a safe landing on suitable ground without excessive power consumption and a reliable docking mechanism for power transmission to AUVs on the sea floor. Moreover, the communication between the SMIS vehicle fleet for georeference and path guidance during the AUV operation is essential. A modular design also allows operation in ROV mode, which expands the field of application.
Unmanned surface vehicles (USV) increasingly gain importance in all areas of marine engineering and natural sciences. Different measuring vehicles are used for short-term measurements with various adaptable sensors. The operation time of these vehicles is limited to few hours. Moreover, long endurance vehicles were designed for long-term missions, generating energy from solar, wind or waves, which are suitable for low-power applications. This paper describes the conceptual design and automation aspects of an innovative ocean-going autonomously acting unmanned surface vehicle. As the vehicle should act as communication node for deep-sea communication up to 6.000 meters, the main challenge is designing a low noise vehicle with reduced motions in waves. The vehicle is supposed to operate autonomously for at least one week. Hence, a hybrid energy system has been designed using batteries and a fuel cell. The automation system allows the vehicle to solve missions in a full autonomous way with minimum operator intervention. The paper closes with aspects of the vehicle construction and first trials.
In this paper, a framework for guidance, navigation and control of marine vehicles is proposed. The focus is on application of unmanned surface vehicle for performing high accuracy measuring tasks. The desired maneuvering path is defined as a combination of standard path sections and delivered to the guidance system. The measurements are filtered and the unmeasurable states are estimated in navigation system and fed back to the guidance and control systems. An extended Kalman filter based approach is used in navigation system, in order to take the nonlinear behaviors of the system into consideration. The proposed control scheme is a modular system consisting of a cascade structure, where the unified inner loop is responsible for velocity control and the outer loop can be adapted independently to various missions. The model parameters are estimated based on subspace identification method using data obtained from a measuring vehicle, MESSIN. The results have been further used for design of control and navigation systems. The performance and effectiveness of the proposed framework are demonstrated on a model for a path following mission.
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.
Parametric roll is a dangerous resonance phenomenon for ships caused by time-varying restoring forces. The resulting large roll oscillations may endanger the ships safety and possibly lead to capsizing. The susceptibility of container ships to parametric roll resonance has caused considerable research activities in the development of control and operational strategies to avoid large roll motions.
In this paper, a novel approach to the active control of ships experiencing parametric roll resonance is presented. The methodology of extremum seeking control is used to iteratively determine the set-point for the wave encounter frequency in order to avoid the conditions for the onset and build-up of parametric roll. The desired trajectory for the wave encounter frequency is tracked by mapping it to the ship speed and heading angle by a control allocation, formulated as a constrained optimization problem, and consequently by implementing speed and heading controllers. The combined variation of the speed and heading angle is shown to efficiently drive the ship out of the parametric roll resonance region.
A comprehensive and extensive study of the latest research in control systems for marine vehicles. Demonstrates how the implementation of mathematical models and modern control theory can reduce fuel consumption and improve reliability and performance. Coverage includes ocean vehicle modeling, environmental disturbances, the dynamics and stability of ships, sensor and navigation systems. Numerous examples and exercises facilitate understanding.
Handbook of Marine Craft Hydrodynamics and Motion Control is an extensive study of the latest research in hydrodynamics, guidance, navigation, and control systems for marine craft. The text establishes how the implementation of mathematical models and modern control theory can be used for simulation and verification of control systems, decision-support systems, and situational awareness systems. Coverage includes hydrodynamic models for marine craft, models for wind, waves and ocean currents, dynamics and stability of marine craft, advanced guidance principles, sensor fusion, and inertial navigation.
This important book includes the latest tools for analysis and design of advanced GNC systems and presents new material on unmanned underwater vehicles, surface craft, and autonomous vehicles. References and examples are included to enable engineers to analyze existing projects before making their own designs, as well as MATLAB scripts for hands-on software development and testing. Highlights of this Second Edition include:
- Topical case studies and worked examples demonstrating how you can apply modeling and control design techniques to your own designs
- A Github repository with MATLAB scripts (MSS toolbox) compatible with the latest software releases from Mathworks
- New content on mathematical modeling, including models for ships and underwater vehicles, hydrostatics, and control forces and moments
- New methods for guidance and navigation, including line-of-sight (LOS) guidance laws for path following, sensory systems, model-based navigation systems, and inertial navigation systems
This fully revised Second Edition includes innovative research in hydrodynamics and GNC systems for marine craft, from ships to autonomous vehicles operating on the surface and under water. Handbook of Marine Craft Hydrodynamics and Motion Control is a must-have for students and engineers working with unmanned systems, field robots, autonomous vehicles, and ships.
A detailed six degree-of-freedom (DOF) nonlinear dynamic model of an Unmanned Sea Surface Vehicle (USSV) is developed. Models of the significant hydrodynamic effects including radiation-induced and damping forces and moments are incorporated. Disturbance models of forces and moments caused by ocean currents, waves, and wind are also included. Detailed models of the actuators including thrusters/propellers and control surfaces are included. To illustrate the importance of a six DOF modeling and the impact of disturbances, simulation results with two different controllers are presented. The detailed mathematical modeling in this paper is intended to provide the appropriate framework for a control design which explicitly addresses the six DOF USSV dynamics along with the disturbances.
This paper discusses the theoretical model of an autonomous surface craft (ASC) with respect to the performance of basic sensors usually available onboard small and relatively low- cost vessels. The aim is to define a practical model and the corresponding identification procedure for simulation, guidance, and control of this class of vehicles. The work is supported by the extended at-sea trials carried out with the autonomous catamaran prototype Charlie2005.
Herausforderungen und Besonderheiten beim Entwurf eines USV (unmanned Surface Vehicle) fr hydrographische Aufgaben
- S Ritz
- M Kurowski
- F Boeck
- M Golz
- D Dewitz
- E Rentzow
- G Holbach
Ritz, S., Kurowski, M., Boeck, F., Golz, M., Dewitz, D.,
Rentzow, E., and Holbach, G. (2014). Herausforderungen und Besonderheiten beim Entwurf eines USV (unmanned Surface Vehicle) fr hydrographische Aufgaben.
STG-Jahrbuch, Band 108(1), pp. 312-325.