A parallel feedforward compensator virtually realizing almost strictly positive real plant

Deals with the design problem of a parallel feedforward compensator which virtually realizes an almost strictly positive real (ASPR) plant. It is well-known that several output feedback based control techniques can easily be applied to the plants having ASPR characteristics. Unfortunately, most real plants do not satisfy this condition. To improve such a situation, the implementation of a parallel feedforward compensator (PFC) which causes a non-ASPR plant to become virtually ASPR has been discussed. Here, a simple and systematic method of composing such a PFC, which can be applied to a broader class of SISO plants, is considered. The effectiveness of the result obtained is examined by applying them to an example of simple adaptive control