Research on a Pitching Movement Mode of A Water Surface Monitoring Catamaran Unmanned Craft

Yan Shi , Baojiang Wang, Songling Yang, Shasha Gao, Tianming Hu

In this paper,a water surface monitoring catamaran unmanned craft was taken as the research object,and a series of static water pitch attenuation tests were carried out under different drafts and different initial pitch angles.According to the principle of dynamic balance in the pitching motion, the identification mathematical models of four pitch motion modes are established by changing the composition of restoring torque.Based on the theory of system identification  and the idea of genetic algorithm, the software of system identification is programmed with C# language.A better mathematical model and equation of motion are identified through the identification of test data.Using the equation of motion for forecasting,the relative errors between the predicted values and the experimental values are in good agreement, which proves the feasibility and reliability of the system identification method.Finally, the processed data is analyzed and the relevant hydrodynamic coefficient curve is given. The variation law of each moment coefficient affecting the pitching motion with the draft and the initial pitch angle is analyzed.The ship's pitching motion is characterized by nonlinearity. Under the disturbance of navigation conditions and environment, its dynamic characteristics will produce uncertainty. If it can be accurately and effectively predict the movement of the ship in the next few seconds, it will have a great impact on navigation decisions.The research in this paper can predict the future navigation parameters and motion posture of unmanned boats.At the same time, it provides a reference for studying the wave resistance of such boats and the optimized design of subsequent boats.Provide technical support for improving the wave resistance of unmanned boats, and propose corresponding improvement methods.

https://dx.doi.org/10.31873/IJEAS.5.9.16