Robust Output Feedback Controller For a Class of Nonlinear Systems with Actuator Dynamics

Abstract

Abstract This paper addresses a simple robust output feedback controller, which suits a class of nonlinear dynamical systems. It takes into account the dynamics and limitations of the actuator. This setting appears in industrial problems such as flow rate control for hydraulic turbines which is used for speed control, where controller gains tuning is important to avoid violent input signals that could excite unstable dynamics, in addition to the limitation of the actuator in use. A systematic approach is proposed to compute the parameters of a simple control law optimally to minimize the tracking error. This approach is divided into two steps. Firstly, computing bounds on some of the system’s parameters and variables, then solving a nonlinear constrained optimization problem (offline). Stability analysis is carried out to guarantee that obtained parameters stabilize the system while keeping the tracking error below a certain bound. A numerical example is given to illustrate the relevance of the proposed controller.