在过阻尼情况下，典型二阶系统有两个相异的实数极点，其阶跃响应实际上是两个一阶系统响应的叠加。（ωn＝5），不断增大ζ值，观察每个ζ值下两个实数极点间的距离；同时绘出两个实数极点分别对应的一阶系统响应和二阶系统的响应，观察它们间的关系-In the overdamped case, the typical second-order system has two distinct real poles, and its step response is actually the superposition of the two first-order system response. (Wn = 5), increasing zeta values​ ​ , observing the distance between the two real poles each zeta value　draw two real poles, respectively, corresponding to a first-order system response and the response of the second-order system, observe them relationship