# ECE 5774 - Nonlinear Systems Theory (3C)

Course Description

Introduction to the theory of systems of coupled, nonlinear, time-varying ordinary differential equations: existence and uniqueness of solutions; continuous dependence on parameters; stability of equilibria and stability analysis techniques; input-to-state stability; input-output stability; nonlinear control design techniques including input-state and input-output feedback linearization, backstepping, and sliding mode control.

Why take this course?

Nonlinear systems theory provides a theoretical framework for studying a large class of systems that are not amenable to linear systems techniques. Moreover, nonlinear techniques can strengthen conclusions about the behavior of those systems which are amenable to linear analysis. Nonlinear systems theory also forms the basis for a variety of nonlinear control design methods that can improve closed-loop performance and robustness beyond the capabilities of linear control design methods.

Learning Objectives

• State and assess conditions for local and global existence and uniqueness of solutions of a nonlinear time-varying state equation.
• Apply Lyapunov's direct and indirect methods for determing stability of equilibria.
• Apply advanced stability analysis techniques, including Lasalle's invariance principle and Barbalat's lemma.
• Define the L2-gain of a system and use the small-gain theorem to assess stability of a feedback interconnection.
• Determine whether a given system can be linearized through state or output feedback and apply these techniques.
• Determine whether a given system can be controlled through backstepping or sliding mode control and apply these techniques.