FREQUENCY-DOMAIN PERFORMANCE BOUNDS FOR UNCERTAIN POSITIVE REAL SYSTEMS

An important part of feedback control involves analyzing uncertain sys tems for robust stability and performance, In certain applications, su ch as collocated control of flexible structures, the plant is positive real, Hence, closed-loop stability is unconditionally guaranteed as l ong as the controller is also positive real, Most of the performance r obustness analysis results in the literature, however, will not always yield finite performance bounds for the case of closed-loop systems c onsisting of uncertain positive real plants controlled by strictly pos itive real compensators, These results are obviously conservative sinc e this class of systems is unconditionally stable, Majorant analysis i s used to develop tests that yield finite frequency-dependent performa nce bounds for the described case, The results are specialized to the case of static, decentralized collocated rate feedback and dynamic, co llocated rate feedback, These results are compared to previous majoran t performance bounds and performance bounds resulting from real struct ured singular value analysis.