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Hammerstein-Wiener (H-W) identification problem is investigated under practical considerations for industrial plants. The main consideration in these cases is inability to apply arbitrary input signals. An algorithm is proposed to identify H-W model for industrial systems, in the presence of noise and disturbance. The identification problem is changed into a constrained optimisation problem and is solved by minimising the non-linear functions modelling error. To improve the efficiency of the proposed method, the known information about non-linear functions are used. To make the proposed method applicable for general systems with hard non-linearities, non-linear functions are described by some ordered pairs. A pressure control valve that is used for anti-surge protection of an air compressor in the second refinery of South Pars Gas Complex is considered as the case study to demonstrate the effectiveness of the proposed algorithm. Seventy-five percent of the gathered data during the time is used for identification and the remaining 25% is used for verification of the resulted model. Verification of the obtained H-W model showed that accuracy of the identified model is more than 95%.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Parametric modelling of uncertainties has been considered for switched linear systems in the past few years to improve the efficiency of robust stability analysis. The main goal of this paper is simultaneously alleviating conservatism and computational effort for robust stability analysis and stabilisation of arbitrary switched linear systems with uncertain parameters. For this purpose, stability conditions are revised and some constraints are relaxed. First, an improved weighted stability bound is proposed which is larger than previous results. Since the obtained stability bound depends on the chosen Lyapunov function, an optimisation problem is also given to determine its maximum value. Then, using the stability results, robust stabilisation of parametric uncertain switched linear systems under arbitrary switching is investigated. In this regard, a design method is presented to offer a static state feedback control law. The conservatism of the proposed control law is reduced by relaxing the constraint on upper bound of a matrix variable. Finally, illustrative examples are included to demonstrate the effectiveness of the proposed method.