Robust tracking control design to nonlinear plants with perturbation using operator-based observers

Abstract

In this paper, an operator-based robust tracking control design for nonlinear plants with perturbation is proposed by using robust right coprime factorisation approach and operator-based observers. In the real industrial process, most of the controlled systems have nonlinear characteristics, including unknown uncertainties consisting of modelling errors and external disturbances. Considering the nonlinearity and uncertainties, an operator-based robust nonlinear perfect tracking control using robust right coprime factorisation is investigated. That is, first, because the unknown uncertain plant generates difficulties in designing realisable operator controllers to obtain the desired tracking performance, an operator state observer and an operator disturbance observer based on nominal plant properties are designed to compensate the effect of uncertain plant. Second, a realisable operator-perfect tracking controller is designed to improve the control performance and to realise the perfect tracking. Based on the proposed designed scheme, the designed system is robustly stable and perfect output tracking performance can be realised. Finally, the effectiveness of the proposed method is demonstrated by a simulation example.