Tracking Controller Design for Linear Systems in Presence of Multiple Saturation Constraints

We are considering the problem of controlling discrete-time linear systems that are subject to multiple saturation constraints. Specifically, we consider systems that are driven by an actuator whose output is subject to magnitude plus rate saturations. Moreover, the output of the considered plant is supposed to be intrinsically saturating. Then, aiming to guarantee the tracking of (compatible) reference signals, a suitable saturated linear controller is designed and the closed loop of the control system is analyzed using input–output stability approach. This allows defining the necessary conditions that ensure good tracking performances. Namely, it is shown that perfect output-reference tracking could be ensured in case of varying with l2-vanishing rate inputs. In addition, in case of arbitrary reference inputs, it is shown that the less changing (in the mean) the inputs are, the better the average (output-reference) tracking quality is. This result entails good matching features as the system dynamics are assumed to be non-minimum phase and subject to multiple saturation constraints. A numerical example is provided to illustrate the application of the proposed control strategy. © 2016, Brazilian Society for Automatics--SBA.