Robust decentralized PID controller design: A case study

Robust stability is an important aspect in control of real world systems, since uncertainties have to be considered in dynamic system models. The basic required quality of the system is its stability in the whole uncertainty domain called robust stability. This paper studies the robust decentralized controller design for a quadruple tank process, [3,4]. For this case study, several important aspects of system analysis are shown (pairing, stabilizability via decentralized control). The main contribution is the decentralized PID controller design in both frequency and time domains, analysis and comparison of results. The obtained results are supported by simulations used to demonstrate and compare the different approaches.