This paper addresses the trajectory tracking control problem of a class of nonstrict-feedback nonlinear systems with the actuator faults. The functional relationship in the affine form between the nonlinear functions with whole state and error variables is established by using the structure consistency of intermediate control signals and the variable-partition technique. The fuzzy control and adaptive backstepping schemes are applied to construct an improved fault-tolerant controller without requiring the specific knowledge of control gains and actuator faults, including both stuck constant value and loss of effectiveness. The proposed fault-tolerant controller ensures that all signals in the closed-loop system are semiglobally practically finite-time stable and the tracking error remains in a small neighborhood of the origin after a finite period of time. The developed control method is verified through two numerical examples.

Adaptive Fuzzy Finite-Time Control of Nonlinear Systems With Actuator Faults

Adaptive neural networks finite-time tracking control for non-strict feedback systems via prescribed performance

This work investigates a finite-time adaptive fuzzy tracking control problem for a class of nonstrict feedback nonlinear systems from a new point of view. A new concept, named finite-time performance function (FTPF), is defined in this paper for the first time. Moreover, a finite-time adaptive state feedback fuzzy tracking controller is derived based on fuzzy approximation, backstepping technique and prescribed performance control (PPC), which guarantees that all the signals of the closed-loop system are bounded, the output tracking error converges to a prescribed arbitrarily small region within a finite-time interval, and maximum overshoot is not more than a predefined level. In addition, a controller design process is given which is less complex than the existing finite-time control design methods. Three simulation studies are provided to verify the feasibility and effectiveness of the theoretical finding in this study.

A Novel Finite-Time Adaptive Fuzzy Tracking Control Scheme for Nonstrict Feedback Systems

This paper focuses on the problem of adaptive finite-time fault-tolerant control for a class of non-lower-triangular nonlinear systems. The faults encountered in the control system include the actuator faults and the abrupt system fault. By applying backstepping design and neural networks approximation, an adaptive finite-time fault-tolerant control scheme is developed. It is shown that the proposed controller ensures that all signals in the closed-loop system are semiglobally practically finite-time stable and the tracking error converges to a small neighborhood around the origin within finite time. The simulation is carried out to explain the validity of the developed strategy.

Finite-time adaptive fault-tolerant control for nonlinear systems with multiple faults

This paper investigates an adaptive finite-time control (FTC) problem for a class of strict-feedback nonlinear systems with both time-delays and quantized input from a new point of view. First, a new concept, called preassigned finite-time performance function (PFTF), is defined. Then, another novel notion, called practically preassigned finite-time stability (PPFTS), is introduced. With PFTF and PPFTS in hand, a novel sufficient condition of the FTC is given by using the neural network (NN) control and direct adaptive backstepping technique, which is different from the existing results. In addition, a modified barrier function is first introduced in this work. Moreover, this work is first to focus on the FTC for the situation that the time-delay and quantized input simultaneously exist in the nonlinear systems. Finally, simulation results are carried out to illustrate the effectiveness of the proposed scheme.

Direct Adaptive Preassigned Finite-Time Control With Time-Delay and Quantized Input Using Neural Network

The problem of adaptive practical finite-time control is considered for a class of single-input and single-output non-linear systems, in which the system non-linear functions are assumed to be unknown. By combining adaptive fuzzy control approach with the backstepping technology, a backstepping-based adaptive fuzzy finite-time control scheme is proposed. In the control design procedure, fuzzy logic systems are employed to identify the non-linear uncertainties. The stability analysis of the adaptive closed-loop systems is proposed based on the finite-time Lyapunov stability theory. The proposed adaptive fuzzy controller guarantees that all the closed signals are semi-global practical finite-time stability while the tracking error converges to a small neighbourhood of the origin. Finally, simulation results are presented to validate the effectiveness of our results.

Bing Chen

Papers

Adaptive finite-time control for a class of uncertain high-order non-linear systems based on fuzzy approximation