Analysis of the Pitching Motion Mode of Three-body Rescue Unmanned Craft Based on System Identification

Di Zhang, Songlin Yang, Zhaozhao Ma

In view of the excessively large pitch of the unmanned craft, the navigation performance may be degraded. Taking the vertical motion mode of the new three-body unmanned craft model as the research object, the pitch attenuation test was carried out in stable water. Now we established four mathematical models for tilting system identification, it based on the system identification method and the improved programming idea of genetic algorithm, adapting the system of tilting motion mode system identification. It is concluded that with the more draught, the more peak value of pitching speed, and with the increasing the time of the craft model to reach steady. Secondly, the equation of the model of pitch motion of the craft with the best effect is obtained, and the feasibility and adaptation of the model and the reliability of the software; finally, the three-body craft model has the anti-rolling effect, but in a small angle, the variation interval of linear damping moment M of catamaran model is relatively stable from 0.12 to 0.085. The system identification method and software provide a feasible way for such three-body unmanned craft pitching and other swaying modes.