THE SOFTWARE PACKAGE FOR THE CATAMARAN ROLL STAND IN WIND WAVE CONDITIONS SIMULATION

Abstract

The article is devoted to the actual problem of catamaran roll imitation, software and algorithms that allow to implement this simulation. The relevance arises from the need to test navigation devices and their algorithms, to build large simulator complexes to reproduce roll and impulses of surface, air and ground-based vehicles. This article will focus on the description of software and algorithms for developing a roll simulator of a catamaran located on the sea surface when it disturbed by windwave influences. The simulation test bench for reproducing the catamaran roll includes a Stewart platform, sensors, microcontrollers and an operator's personal computer. The upper part of the platform moves like the deck of a catamaran, and the lower part is rigidly fixed. The experimental results are taken into account by sensors mounted on a movable part and processed by a microcontroller-navigation system prototype. It is believed that the navigation system should receive data about the pitching object and return to the operator a state vector containing the angle and speed of roll, angle and speed of pitch, height and speed of heave. The applied mathematical models describe the dynamics of a catamaran and a control system that reduces the amplitude of pitching, external disturbances of the sea wave formed by the Pearson-Moskowitz spectrum. To obtain the catamaran's roll trajectories, the Runge-Kutta 4th order algorithm with a fixed step is implemented, and for filtering and restoring the full vector of catamaran states the Kalman filter is implemented according to the “delayed” scheme. Software has been developed to reproduce the roll of a catamaran on a simulation test bench, filter and restore the state vector, graphically display the results of the experiment in the form of graphs, and save the results in files. For a better interpretation of the results, the input parameters of the graphical interface and algorithms have simple visual parameters: the wind speed and direction, the initial state of the catamaran and the service ones, and the results are presented in the form of graphs. The article provides a detailed description of the relationship between program modules, applied mathematical algorithms, and input and output parameters. The simulation results show a sufficient quality of reproduction of the rolling of the catamaran. However, minor errors were identified due to the mechanical limitations of the applied kinematic model.