Decentralized Robust Control of MIMO Systems: Quadruple Tank Case Study

This paper presents part of material concerning decentralized control, taught in graduate course Control of Complex Systems. We present some basic aspects of decentralized control design concerning stability and performance and illustrate them on a case study: virtual model of a quadruple tank process. Control structure selection based on performance relative gain array (PRGA, Hovd, Skogestad, 1992) is used and its ability to evaluate the achievable performance is discussed. Robust stability condition for decentralized control is considered, which provides the upper level on subsystems, thus limiting the performance.