Analysis of Robust Pole Clustering in a Good Ride Quality Region for Uncertain Matrices

This paper presents a general analysis of robust pole clustering in a good ride quality region of aircraft, a specific non-Ωtransformable region, for uncertain matrices. The region is an intersection of a ring and a horizontal strip, located on the left half-plane. From experiments, it is known that the control system with poles located in this specific region provides a good ride quality for aircraft. The paper applies Rayleigh principle along the norm theory to analyze robust pole clustering within this good ride quality region since the generalized Lyapunov theory is not valid for non-Ω-transformable regions. The mainly concerned uncertainties are unstructured uncertainties. A simple extension of the results for structured uncertainties is also provided. Two examples illustrate the results for a perturbed closed-loop system matrix of F16 aircraft approximation model. The results are useful for robustness analysis and, especially, analysis of robust good ride quality of aircraft, shuttles, and space station via robust pole clustering in this region for their system matrices.