One possibility is to add the pole at the origin to increase the system’s type, and add the
compensator zero immediatly to the left of the rightmost open loop pole. For the plant the open loop
zeros are: -0.00025, -0.00164. The open loop poles are: -0.000092, -0.0032 and -0.00122. Thus the
compensator will be of the form
s
G s K s C
( ) ( 0.0001)
+
= . This will modify the root locus as
shown. However the gain can be adjusted to preserve the original pole locations without increasing
much the overall system’s settling time. Using Sisotool K = 0.04 was found as suitable.