用四阶龙格库塔法求非线性系统的输入相应，同时用simulink建模比较。 -Using fourth-order Runge-Kutta method for the corresponding input nonlinear systems, and modeling using simulink comparison.

用四阶龙格库塔法来求含有N阶导数的微分方程组的解，需要自己输入改动的数值-Using the fourth-order Runge-Kutta method to find the solution of differential equations with N-th derivative, we need to input the numerical value