2015/10/21 阶系统的自由响应（相等实根） yee(t)）=Ae+A,tep 马=3<0 马=马2=0 =3>0 ↑1mg ↑mg ↑mg Real Real Real y(0 y(0 Time (r) Time (f) Time (f School of Mechanical Engineering ME369-lecture 6.5 Shanghai Jiao Tong University Fall 2015 阶系统的自由响应（共轭复根） yie()=Ae“cos(Bt+) a<0 a=0 a>0 Img. ↑Ig mg. Real Real Real yH(1) yH(() (0 Time (r) Time(f) Time(r) School of Mechanical Engineering ME369-lecture 6.5 Shanghai Jiao Tong University Fall 2015 32015/10/21 3 ME369-lecture 6.5 Fall 2015 School of Mechanical Engineering Shanghai Jiao Tong University 二阶系统的自由响应（相等实根） 1 1 1 2 ( )   s t s t free y t Ae A te 1 2 s s   0 1 2 s s   0 1 2 s s   0 ME369-lecture 6.5 Fall 2015 School of Mechanical Engineering Shanghai Jiao Tong University 二阶系统的自由响应（共轭复根） ( ) cos( )     at free y t Ae t   0   0   0