محمدرضا رمضانی آل

Bellman's optimality principle states that designing an optimal controller for continuous-time bilinear systems with known system dynamics has a high computational complexity. As a result, controller design typically uses approximation techniques that depend on system dynamics knowledge. This problem will become more challenging when the system dynamics are unknown. Identifying the bilinear system dynamics through identification techniques is the first step toward overcoming this. It is well known that the identification methods give the designer a linear model to use in the controller design, based on the input and output data of the system. This paper proposes a new iterative method to design an optimal controller for a bilinear system whose dynamics are unknown, using an online adaptive policy iteration. In the proposed iterative method, instead of knowing the dynamics of the bilinear system, the optimal controller is designed by using the online input information and measurement of states. Also, by applying noise as an input for the system in a certain time interval, the need to measure the states for the next iterations is eliminated. The convergence of the adaptive iterative process to the optimal controller has been presented and proved in a theorem.

Guaranteed cost control (GCC) is an impressive method of controlling nonlinear systems‎, ‎incredibly uncertain switched systems‎. ‎Most of the recent studies of GCC on uncertain switched linear systems have been concerned with asymptotic stability analysis‎. ‎In this paper‎, ‎a new robust switching law for time-delay uncertain switched linear systems is designed‎. ‎First‎, ‎the switching law is designed‎, ‎and second‎, ‎a state-feedback controller based on Lyapunov-Krasovskii Functional (LKF) is designed‎. ‎Also‎, ‎using Linear Matrix Inequality (LMI) particular condition for the existence of a solution of obtained switching law and controller is achieved‎. ‎Consequently‎, ‎in the presented theorems‎, ‎the exponential stability of the overall system under switching law and controller is analyzed‎. ‎Finally‎, ‎theoretical results are verified via presenting an example.