Flight controller design using IQC to satisfy stability margin requirements of MIMO system

Abstract

1. Abstract This paper introduces the gain scheduled flight controller design method satisfying various design requirements, including stability margin. As a fundamental design requirement for flight control system, the stability margin for MIMO (Multi Input / Multi Output) system is defined as a generalized requirement formulation. Using IQC(Integral Quadratic Constraints) synthesis, this stability margin requirement can be considered as a kind of mixed sensitivity H °° problem with complex constant weights. LMI(Linear Matrix Inequality) theory is used to solve the derived mixed sensitivity problem. Gain scheduled technique is also adopted to satisfy the requirement in the entire flight region. The effectiveness of the proposed method is verified by designing the longitudinal and lateral-directional flight controllers for the winged re-entry space vehicle in approach and landing phase.