Applet shows the locus of a system with 3 open loop poles. This system has 5 asymptotes at ±60°, and -180°. Since 2 of the asymptotes cross the imaginary axis, then the system will always become unstable if K is made large enough.

Eg parameters (K, 2.5, 1.7, 1.15, 0.5, 0.2, 0.4, 1.55) has 5 poles at -2.5, -1.7, -1.15, -0.5, -0.2 and is stable if K <= 1.72. Unstable for 1.72 < K < 35.69. Stable for 35.69 < K < 46.72. Unstable for 46.72 < K.

Eg parameters (K, 1.5, 1.5, 1.5, 1.5, 1.5, 0.5, 3.0) becomes unstable if K > 3.06.

Gif image below shows how applet should appear.

COPYRIGHT © 2006 Cuthbert Nyack.