Contribution to adaptive control of triangular nonlinear systems with application

Abstract

In this thesis, we are interested in the study and development of composite adaptive control strategies for uncertain nonlinear systems in lower triangular form. Composite tuning functions based adaptive backstepping control scheme suffers from the problem of explosion of complexity caused by the repeated derivations of virtual control inputs. By using the composite adaptive and robust adaptive dynamic surface control, and composite immersion and invariance based adaptive command filtered backstepping control methods, the problem of explosion of complexity is eliminated. Composite sum, projection and δ-modification based gradient and least squares adaptive laws are used. Stability analysis of the proposed composite adaptive control schemes is performed by using the Lyapunov stability theory to guarantee that all signals in the closed-loop system are bounded. Simulation results of an electromechanical system are presented to show the effectiveness of the proposed composite adaptive control techniques.