Robust model following systems

Abstract

This paper proposes a robust model following (RMF) system which realizes good properties such as asymptotic stability, disturbance rejection and model following with reduced sensitivity for plant parameter variation. For a given plant, the RMF system is constructed as a double perfect model following system which uses two models, one used to give a good response to be followed and the other to provide the robustness as well as to reduce the sensitivity. It is shown that RMF system can be generally designed for the plant whose output has the same dimension as the input. It is also shown that when some conditions about the forms of the system and parameter variations are satisfied, the plant output which has the larger dimension than the input can be made robust. Furthermore, the robustness for variations of parameters other than the plant is discussed. A design procedure for the RMF system is given. As an example, the flight control system of a helicopter is designed and its characteristics are examined by simulation which confirms the robustness and remark able sensitivity reduction.