Numerical investigation on seakeeping performance of SWATH with Three Dimensional Translating-pulsating Source Green Function

The Research on Rolling Motion Model of the SWATH-USV Based on System Identification

“…But its natural cycle is much greater [2] . It is easy to produce large rolling motion when ships navigate in waves, and the large rolling motion exhibits complex nonlinearity [3] .When the SWATH navigates in oblique waves, it is easy to occur the coupling phenomenon of rolling and pitching [4] ,therefore, it is very important to study and predict the roll motion of a SWATH [5] .Model test, however, is an effective means of studying rolling motion,in addition,the system identification method which is based on the optimal design has been applied to rolling motion tests of monohull ship model and trimaran model [6][7] . In this paper, the model test of rolling motion in still water of a SWATH-USV is carried out, then a mathematical model of linear and nonlinear roll attenuation motion modes are established according to the principle of dynamic balance in rolling.After that,the relevant design variables and objective functions are determined respectively, and the genetic and particle swarm optimization algorithm system identification program is written which is based on C#.The rolling test data are identified and analyzed through the program,the results show that the error between the test values and the predicted values is smaller which can prove the reliability of this system identification software.…”