New design method of simple adaptive control for systems with arbitrary relative degree

This paper is concerned with a novel simple adaptive control system design for a non-ASPR (almost strictly positive real) plant without using an ordinary parallel feedforward controller. The proposed scheme consists of decomposition of the non-ASPR plant into an unknown ASPR subsystem and a known subsystem, implementation of the simple adaptive control, and design of H_∞ controller for the known subsystem to track the output of the simple adaptive controller. The advantage of the new approach needs no prior knowledge on the plant