Decentralized Cooperative H∞ Robust Control for Linear Large-Scale System

A decentralized cooperative robust H_∞ controller was proposed for a linear time invariant (LTI) system via a multilevel control approach. This system was modeled as interconnection of subsystems with parameter uncertainty. The multilevel control approach was a two-stage controller design in which the first stage involved constructing a decentralized robust controller using only its states for every uncertain subsystem via linear matrix inequality (LMI) approach to ensure the subsystem stability and achieve a given H_∞ performance level and the second stage carried out a cooperative controller design to reduce the effect of other subsystems and improve the overall system performance. The controller, obtained applying this idea, not only makes the overall system inner stabilized and achieves the H_∞ performance requirements, but also is easy to realize.