Dp 457 en
Robust control of quadruple-tank process
Author: Trnka Václav
Diploma thesis deals with control of linear mathematical model of quadruple-tank process, which represents a system with two inputs and two outputs (MIMO). The uncertainty (perturbation), which reflects the behaviour of real system, is inserted into the model. The goal of this work is to design controllers with classic and advanced methods and to compare their results. The H-infinity control is presented as a tool for robustness and performance analysis and also for robust (resistant to uncertainty) design of controllers. These robust methods (mixed sensitivity, H-infinity loop-shaping, D-K iteration), which consider perturbed model in design phase, are compared with classic methods - decentralized PI controller and LQ regulator, which consider nominal model (without uncertainty) in design phase. Besides time responses, mu-analysis, which verifies influence of uncertainty on stability and performance of control loop, is used for a comparison. At the end of this thesis, results are evaluated and it is determined which controller had the best properties.