Observer-based integral controller using composite nonlinear feedback for saturated control systems

Abstract

Usually, simultaneous improvement of the transient performance and static accuracy is a challenging issue in saturated control systems. Employing an observer and the concept of composite nonlinear feedback, an integral controller is developed for constrained continuous-time systems. To achieve the control goal in the regulation purpose, a linear model is first derived by linearization about the operating point. Some parameters of the integral control are adjusted via the feedback passivation idea. The integral control law would be presented when a passivity condition is satisfied. Adding suitable damping terms to the existing one, the final controller is modified to enhance the response quality of the closed-loop system. The obtained results are evaluated in some numerical real examples. Although such a control method uses linearization, the outcomes of simulations, as well as the calculated performance indexes, discover the efficiency of the designed control system over the comparable ones.

Robust integral controller design based on composite nonlinear feedback in uncertain systems with constrained inputs and external disturbances

“…A robust CNF control based on integral sliding‐mode is designed for uncertain delayed systems under input saturation 29 . Lately, employing the CNF idea, an output‐feedback integral controller is developed for linear systems with saturation 30 …”

“…29 Lately, employing the CNF idea, an output-feedback integral controller is developed for linear systems with saturation. 30 More broadly, employing linear matrix inequality (LMI), many control problems like the stability analysis and the controller synthesis may be converted to an optimization. 31,32 Nowadays, to solve an LMI issue, there are various LMI software packages such as LMILab, YALMIP, SeDuMi, and so on.…”