Algorithms for controlling a motor ship when using a wheeled propulsion-steering complex and an azimuth thruster together

Abstract

The commissioned passenger cruise ship Golden Ring with a set of innovative propulsion systems: a wheel-propulsion steering system and an azimuth thruster is considered. The propulsors of the vessel are equipped with frequency drives, which makes it possible to implement both discrete (step) control of the rotation speed of the propeller wheels and continuous control of the characteristics of these units. Ratio of wheel rpm allows manipulating direction and magnitude of thrust of propulsors. The azimuthal thruster is mounted in the bow of the vessel and allows for a stop in any direction over the entire power range. The mathematical modeling of the motor ship motion is carried out in various embodiments of controlling the process of holding the ship on a given trajectory under wind impact. The parameters of the ship control and control system operation were compared with the use of wheel propulsors during continuous and stepped control, as well as when the ship is kept on course using a thruster. It has been found that in case of discrete (step) control of propulsors, which is used by navigators in manual control, it is difficult to provide good quality indicators of the control process, since the stage of change in the rotation speed of the propeller wheel is quite painful. In this case, a constant change in the rotation speed of one or the other co-forest is required. Discrete control of the thruster (in on/off mode at fixed power) also does not give good results. The implementation of algorithms for automatic control of propulsors in analog mode both using co-forest propulsors and a thruster ensures the movement of the ship along a given trajectory with sufficient accuracy in practice.