In cases when the navigational space of the manoeuvre performed by the ship is severely limited, the procedures making use of the rudder blade, propeller screw, and thrusters are very complicated. Such situations take place when the ship manoeuvres inside the harbour area and in those cases the structure of the control system is very complex. Te article describes the algorithm of multivariable control of ship motion over the water surface, which makes use of the state vector consisting of 6 variables. Tree of them, which are the position coordinates (x, y) measured by the DGPS system and the ship heading y measured by gyro-compass, were obtained experimentally. Te three remaining variables, which are the velocities in surge u, sway v, and yaw r directions, were estimated by Kalman filter, Kalman-Bucy filter and extended Kalman flter, respectively.
The control algorithms making use of these observers were examined using the training ship “Blue Lady” which was navigated on the lake Silm in Ilawa/Kamionka in the Ship Handling Research and Training Centre owned by the Foundation for Safety of Navigation and Environment Protection. Te experimental results obtained using control systems with three observers were finally compared between each other.
The dynamical positioning system is a complex control consisting of a number ofcomponents, including: filters, observers, controllers, and propeller allocation systems.The design and preliminary analysis of operational quality of system operation are usuallydone based on numerical simulations performed with the aid of the mathematical modelof the ship. The article presents a concept of the dynamic positioning system applied tosteering the training ship Blue Lady used for training captains in the ship handling researchand training centre owned by the Foundation for Safety of Navigation and EnvironmentProtection in Ilawa/Kamionka. The simulation tests performed in the numerical environmentof Matlab/Simulink have proved the usability of the designed system for steering a ship at low speed.
This paper presents the designs of two observers, which are: the extended Kalman filterand the nonlinear passive observer. Based on the measured values of ship position andheading, the observers estimate the surge, sway and yaw velocities of the ship motion.The observers make use of the simplified nonlinear mathematical model of ship motion inwhich the neglected ship dynamics and disturbances are modelled using bias. The designedobservers firstly have been simulated on a computer model where their parameters werecalibrated, and then were implemented on the physical model of the training ship “BlueLady” in the ship handling centre in Ilawa-Kamionka. The comparative analysis wasdone with respect to the estimated variables describing the ship motion in three directions: surge, swayand yaw