ABSTRACT
This chapter addresses decentralized backstepping adaptive tracking for nonlinear interconnected systems in the presence of external disturbances. The interactions between subsystems are unknown and allowed to satisfy a high order nonlinear bound. A new smooth function is proposed to compensate the effects of unknown interactions and also the reference inputs. Due to output feedback, local filters are designed to estimate systems states. In contrast to, the designed filters are totally decentralized by using local information. In controller design, the effects of interactions are taken into consideration in the development of local control laws. The term multiplying the control and the system parameters are not assumed to be within known intervals. Besides global stability, a root mean square type of bound is also obtained for the tracking error as a function of design parameters. This implies that the transient tracking error performance can be adjusted by choosing suitable design parameters.
