Martin Kurowski

AGaPaS: A new approach for search-and-rescue-operations at sea:

An innovative, satellite-guided search-and-rescue-system will be presented. This system utilises an autonomous rescue vessel to retrieve overboard personnel. The system acts instantaneously, which significantly increases the chance of survival. It was developed for use on special ships or offshore platforms, where workers are subject to adverse weather conditions and overboard personnel are often discovered too late. A substantial challenge is the automation of the autonomously acting rescue vehicle as well as its integration into the superior search-and-rescue-process. To ensure the fastest possible approach to the casualty without endangering the person, a cascaded control concept has been designed. Two-degree-of-freedom control concepts are used to separate the tracking performance from the disturbance rejection. The inner speed control structure is divided into two parts and consists of the control structure itself with an in-line allocation to the device configuration. The contribution mainly addresses the automation of the rescue vessel, the synthesis of the control system of the autonomously acting vehicle as well as the integration into the superior search-and-rescue-process. Finally, some test results of this complex system are shown.

AdaNav – a modular control and prototyping concept for vessels with variable gear configurations

Abstract According to their tasks and relations, specialized vessels are equipped with modern steering devices like podded drives or thrusters. Such modern steering concepts substantially increase the manoeuvring capability of the vessels. However, mates are not able to handle those gears efficiently, because the relations between action and reaction are far too complex. Automation is needed to support the steering team. The industrial production of wheelhouse systems within the large spectrum of types of manoeuvring gears and their location on vessel hulls is still a hard problem. Finally, each adaptation for the navigation and track guidance system looks like an individual system production. For an easier prototyping and implementation of different steering concepts in navigation and track guidance systems for vessels, a modular concept has been applied by the University of Rostock, Center for Marine Information Systems (CeMarIS). Supported by the Federal Ministry of Economics and Technology, in the joint project “Adaptive Navigation System for Ships” the control of each device was implemented into a new automation strategy for the guidance process to realize an optimal manoeuvrability in motion. At the end of the project, final tests in the Maritime Simulation Center in Warnemunde (MSCW) have demonstrated the efficiency of the developed modular control concepts.

Guidance, Navigation and Control of Unmanned Surface Vehicles

Abstract 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.

AGaPaS - a new approach for Search-and-Rescue-Operations at sea

Abstract An innovative, satellite-guided Search-and-Rescue-System is under development. This system utilises an autonomously acting rescue vessel to salvage a person overboard to increase significantly the chance of survival. It was developed to be used on special ships or offshore platforms, where workers have to act in bad weather conditions and often going overboard of a person will be discovered too late. A substantial challenge is the automation of the autonomously acting rescue vehicle as well as the integration into the superior Search-and-Rescue-Process. The developed cascaded control concepts were designed to ensure the fastest possible approach to the casualty without endangering the person. Therefore, two degrees of freedom control concepts are used to separate the reference values from the disturbances. The inner speed control structure is divided into two parts and consists of the control structure itself with an in-line allocation to the device configuration. The paper mainly addresses the automation of the rescue vessel, the synthesis of the control system of the autonomously acting vehicle as well as the integration into the superior Search-and-Rescue-Process. Additionally, some test result of this complex system are shown at the end of the paper.

Characteristic equation for linear periodic systems with distributed delay

Abstract The paper presents a method for constructing the characteristic equation of SISO linear periodic dynamical systems with distributed delay. The construction bases on a description in frequency domain, and a relation between the characteristic function of the periodic system and the Fredholm denominator of an associated Fredholm integral equation of the second kind. Using the Fredholm calculus, polynomial approximations of the characteristic function are derived. Together with estimation formulae, sufficient conditions for the location of the characteristic roots with respect to the unit circle are provided, i.e. ordinary criteria can be applied for stability investigations. The method is illustrated by an example.

Search-and-Rescue-Operation with an Autonomously Acting Rescue Boat

A novel, satellite-guided rescue system is under development, utilizing an autonomously acting rescue boat to salvage a person overboard to increase significantly the chance of survival. This advanced technology requires new approaches for naval architecture and integration of computer-aided tools to develop and operate such devices. A substantial challenge is the design and the automation of the self-acting autonomous rescue boat which navigates to the person overboard automatically. The design of this free fall rescue vessel guarantees that it will be self-righting. The developed cascaded control concepts were designed to ensure the fastest possible approach to the casualty without endangering the person. A specifically integrated monitoring system supports the entire rescue operation. In this paper, a complex Search-and-Rescue-System for a satellite-supported rescue operation at sea will be presented which couples efficiently independent engineering tasks like naval architecture, control system design as well as information processing and monitoring.

Precise Maneuver Planning for Berth-to-Berth Navigation of Modern Ships

Abstract Modern steering devices for ships lead to an improved control capability and allow independent actions without tugs by mates in use with modern electronics. Within the project AdaNav developed MIMO controller enables DP equivalent functions for ships being able to traverse. The following contribution shows the inclusion of such modern maneuvering quality as computer based assistance system into electronic ship guidance systems like ECDIS. To guarantee fully responsibility of mates the concept bases on introduced planning practice implementing additional waypoints and attributes.

Full-state Manoeuvre Planning System for Marine Vehicles

Abstract Nowadays vessels are often equipped with modern steering devices like thrusters and podded drives. Such modern steering concepts substantially increase the manoeuvring capability of the vessels. Special manoeuvres, such as berthing and cast off manoeuvres, can be performed by controlling all available aggregates without using tug boats, lines and anchors. Furthermore, the reliability of the position information especially in ports and other safety critical areas has been improved by auxiliary systems. The user gets warranted position data, so that control tasks with high safety requirements can be realised automatically, especially in case of decreased visibility. The deficit of todays track control systems is the path planning method to generate the input values of the specific track control systems by the navigating officer, especially in low speed modes. In order to face this lack, new manoeuvre planning algorithms have been developed and embedded in a simulation and test environment. The feasibility of the developed manoeuvre planning methods is demonstrated with one of the most challenging nautical tasks – the berthing manoeuvre.