The Method for Analyzing the Pitching Motion Pattern of a New Surface Unmanned Wing-sliding Boat

Abstract

In this paper, a new surface unmanned wing skate (NUSV) is taken as the research object, and the free decay model test under different drafts and different initial pitch angles is completed. In the case of specially selected regular waves, typical swaying tests against waves and waves were carried out. Four mathematical models for system identification of pitch motion modes are established. Based on the system identification theory and the programming idea of the improved genetic algorithm, the NUSV pitch motion mode system identification software is written in C# language. The system identification software is developed based on experimental technology and an analysis method of ship motion patterns is developed based on the optimization theory. This paper completed the following: (1) compared and calculated the mathematical models of system identification based on four-pitch motion modes and determining their motion modes, (2) based on the results of pitch motion mode identification, the predicted values and the test results are in good agreement, which verifies the rationality of the method and the reliability of the self-compiled software, (3) analyzed the variation law of the relative value of each moment that affects the NUSV pitch decay motion with the draft and initial pitch angle, (4) analyzed the influence of the NUSV in the regular wave. The variation law of each moment of the rocking motion with the draught, wave height, and encounter period, and (5) proposed the idea of establishing a rocking motion pattern map based on the rocking test and optimal identification theory. The method and research results proposed in this paper can provide a reliable motion model for the pitch motion control of this type of boat, and provide technical support for its effective regulation of the adverse effect of the pitch on the boat’s stability. It also provides a reference for the seakeeping of this type of boat and the optimization design of the subsequent boat type. The system identification software written can also be used for system identification of the rocking motion mode of this type of unmanned boat in other directions.