  The key idea of this contribution is the partial compensation of non-minimum
phase zeros or unstable poles. Therefore the integer-order zero/pole is split
into a product of fractional-order pseudo zeros/poles. The amplitude and phase
response of these fractional-order terms is derived to include these
compensators into the loop-shaping design. Such compensators can be generalized
to conjugate complex zeros/poles, and also implicit fractional-order terms can
be applied. In the case of the non-minimum phase zero, its compensation leads
to a higher phase margin and a steeper open-loop amplitude response around the
crossover frequency resulting in a reduced undershooting in the step-response,
as illustrated in the numerical example.
