利用三阶龙格库塔法和理论力学动量矩定理，成功模拟双摆的运动，并克服了显式单步解会使小球飞起来的缺点-Shortcoming fly using third-order Runge-Kutta method and theoretical mechanics Momentum Theorem, successfully simulated double pendulum motion, and to overcome the explicit one-step solution will make small ball