On the robust regulation problem for nonlinear systems using fuzzy immersions

In this paper, a nonlinear robust regulator, based on fuzzy techniques, is proposed as an alternative procedure design to guarantee stability for a wider range of variation in both the exosystem and the immersion. This robust regulator is a fuzzy error feedback controller which relies on the existence of an internal model, obtained by finding, if possible, an observable immersion of the exosystem dynamics, which allows to generate all the possible steady state inputs for the admissible values of the system parameters in order to track and/or reject time-varying references and/or disturbances, while maintaining the stability conditions of the system. Finally, the proposed fuzzy controller scheme is compared with traditional techniques through a case study to test the robustness properties in the face of parameter uncertainties and changes on load disturbances.