求系统单位给定阶跃响应的性能指标（超调量，峰值时间，调整时间 .....），其中，

y，t表示系统节约相应的函数值与其对应时间,函数返回的是阶跃响应的第一(正向)波峰值b1、 阶跃响应的第二(正向)波峰值b2,阶跃响应的超调量sigma,阶跃响应的衰减比n,阶跃响应的衰减率pusi

阶跃响应的衰减震荡周期T,阶跃响应的振荡频率f.-Demand system units for a given step response performance (overshoot, peak time, adjust the time .....), which,　y, t that the system saves the corresponding function value and its corresponding time, the function returns the order Jump to respond to the first (positive) wave peak b1,　step response of the second (positive) wave peak b2, step response overshoot sigma, step response of the attenuation ratio of n, the step response of the attenuation rate pusi　step response of the decay vibration cycle T, the step response of the oscillation frequency f.