μ-interaction measure for unstable systems

• Main Authors: Kariwala, Vinay, Forbes, J. Fraser, Skogestad, Sigurd
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2011
• Subjects: DRNTU::Engineering::Chemical engineering; DRNTU::Engineering::Electrical and electronic engineering::Control and instrumentation::Control engineering; DRNTU::Science::Mathematics::Applied mathematics
• Online Access: https://hdl.handle.net/10356/93819; http://hdl.handle.net/10220/6880; http://www.inderscience.com/search/index.php?action=record&rec_id=15845&prevQuery=&ps=10&m=or
• Institution: Nanyang Technological University

In this paper, we present a method for system stabilization through independent designs of the decentralized controller. The proposed method extends the practical applicability of the conventional μ interaction measure (μ-IM) to unstable systems. The decentralized controller is designed based on a block diagonal approxi- mation that is different from the block diagonal elements, but has the same number of unstable poles as the system. By expressing the μ-IM in terms of the transfer matrix between the disturbances and inputs, we show that the block diagonal approximation can be sub-optimally selected by minimizing the scaled L-inf distance between the sys- tem and the approximation. We present a numerical method for choosing the block diagonal approximation and a simple method for designing the decentralized controller based on the approximation.