Stability Analysis And Control Of Several Classes Of Strict-feedback Nonlinear Systems

For several classes of strict-feedback nonlinear systems,the controller is designed and stability is analyzed in this paper based on fuzzy logic system,backstepping technique,command filter and Nussbaum function.The specific contents are as follows:1.A fuzzy tracking controller is constructed for a class of strict-feedback nonlinear systems with full state constraints.Because fuzzy logic system is used to approximate the unknown nonlinear functions,the proposed control scheme addresses the finite-time tracking control problem.2.A finite-time tracking controller is constructed for a class of stochastic nonlinear systems with parametric uncertainties.By constructing a tan-type Barrier Lyapunov Function,the proposed control scheme ensures that the closed-loop system is finite-time stable and the output tracking errors converge to a sufficiently small neighborhood of the origin in finite-time.3.A command filter-based finite-time adaptive fuzzy control problem is discussed for a class of nonlinear systems with uncertain disturbance.By using the error compensation signals and fuzzy logic system,a fuzzy control scheme is proposed to ensure that the output tracking errors converge to a sufficiently small neighborhood of the origin in finite-time and all signals in the closed-loop systems are bounded.4.To deal with a class of nonlinear systems with unknown control directions,a command filter-based adaptive control scheme is proposed.In the design process,fuzzy logic system is required to handle nonlinear functions,command filter is employed to settle the explosion of complexity problem arose from repeated differentiation of virtual control function and Nussbaum function is introduced to deal with the problem of unknown control directions.