Loop-shaping Design with Constant Magnitude loci in Control Education

This educational contribution introduces the sensitivity peak beside the complementary sensitivity peak as indices of relative stability in the loop-shaping approach design of SISO control systems, through the use of an Extended Nichols Chart (ENC) which displays constant magnitude loci of the sensitivity function along with the well-assessed constant magnitude loci of the complementary sensitivity. The advantages of using the ENC in an educational context will be shown in the control design of an unstable laboratory process.