X2(s) X(s) G(s) G(s) X1(s) X X1(S) X1(s) X1(s) x1(s) o X3(s) x3( x1(s) E(S) x1(s) E(S) E(s) X2(s) E(s) X2(s) E(S) 图230结构图与信号流图的对应关系⚫ G(s) (a) ( ) 1 X s (b) (c) ( ) 1 X s 图2.30 结构图与信号流图的对应关系 ( ) 1 X s ( ) 1 X s ( ) 1 X s ( ) 1 X s ( ) 1 X s ( ) 3 X s ( ) 2 X s E(s) E(s) ( ) 1 X s ( ) 2 X s ( ) 3 X s E(s) E(s) -1 E(s) ( ) 1 X s ( ) 2 X s ( ) 1 X s ( ) 2 G(s) X s