Design of robust quantitative feedback theory controllers for pitch attitude hold systems

Abstract

terns. Higher-order systems can be analyzed in a similar manner by defining a separate coupling parameter for every pair of subsystems. A simple test structure consisting of a cantilever beam with attached disk has been used to experimentally verify the stability analysis. This structure exhibits bending and torsion at nearly the same frequency. The force actuators can be relocated so that the degree of coupling between bending and torsion can be easily adjusted. Initial condition responses on this structure for several coupling values confirm that the performance severely degrades as the degree of coupling approaches the critical value, where the system becomes unstable for both decentralized and centralized controllers. Thus, to ensure stable control, the actuators should be located so that the coupling they induce is sufficiently different from the critical value. Acknowledgments The research described in this document was made possible in part by funds from an NEC Fellowship to Peter H. Meckl, provided by NEC Corporation, Tokyo, Japan. We also gratefully acknowledge Haruo Shimosaka from Meiji University, Kawasaki, Japan, for helping with the design and analysis of the test structure.