Design of PDC fuzzy controllers under persistent disturbances and application in mechanical systems

This article proposes a method for designing parallel-distributed compensation fuzzy state-feedback controllers for nonlinear systems affected by persistent disturbances. Firstly, some methods proposed in the literature are analyzed and their weak points are discussed. A design scheme based on minimizing the 1-norm between the disturbance signal input and output is then proposed. Specifically, an upper bound on this norm, the ★-norm, is minimized, which, unlike the 1-norm, can be formulated in terms of linear and bilinear matrix inequalities. Finally, this method is applied to a nonlinear mechanical system.