Adaptive fuzzy finite‐time fault‐tolerant control of nonlinear systems with state constraints and input quantization

Abstract

Summary This article concentrates on an adaptive finite‐time fault‐tolerant fuzzy tracking control problem for nonstrict feedback nonlinear systems with input quantization and full‐state constraints. By utilizing the fuzzy logic systems and less adjustable parameters method, the unknown nonlinear functions are addressed in each step process. In addition, a dynamic surface control technique combined with fuzzy control is introduced to tackle the variable separation problem. The problem for the effect of quantization and unlimited number of actuator faults is tackled by a damping term with smooth function in the intermediate control law. Finite‐time stability is achieved by combining barrier Lyapunov functions and backstepping method. The finite‐time controller is designed such that all the responses of the systems are semiglobal practical finite‐time stable and ensured to remain in the predefined compact sets while tracking error converges to a small neighborhood of the origin in finite time. Finally, simulation examples are utilized to testify the validity of the investigated strategy.

Adaptive fixed‐time tracking control for stochastic pure‐feedback nonlinear systems

“…The new adaptive technology greatly relaxed the restriction of the control coefficients. To be specific, in contrast to the most existing researches, 6,12,18 the knowledge of upper bounds of UVCC in the process of stability analysis is no longer needed in this article, which is realized by employing the bound estimation method, the backstepping technique and the construction of smooth function. Different from the common Lyapunov function structure, this article proposes a novel construction by adding the lower bound of control coefficient, which is essential to establish the required stability.…”

“…Till now, the FTC technique was widely applied to settle down the adaptive tracking problems of nonlinear systems. [7][8][9][10][11][12] However, a distinguished feature of the aforementioned researches is that the predefined time of the FTC schemes depend on the initial conditions and increase along with the deviation between initial state and equilibrium point. Moreover, not all the initial conditions are available in practical systems.…”

“…(2) In contrast to the general structure of Lyapunov function, a novel construction of Lyapunov function is proposed by adding the lower bound of the UVCC, which plays an essential part in ensuring the desired stability. (3) In contrast to the previous researches 6,12,18 which assumed that the virtual control function to be one or known or require the knowledge of upper bounds and first derivatives of the virtual control coefficients in the stability analysis, the requirement of the UVCC is relaxed in this research. Since the virtual control functions and the upper bounds of the virtual control coefficients may be difficult to determine in practice.…”

Finite‐time state‐feedback stabilization of high‐order stochastic nonlinear systems with an asymmetric output constraint

“…A series of results have emerged to manipulate the issues of finite-time stabilization. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] For instance, Reference 14 investigated the problem of stochastic high-order state feedback for the time-varying delay nonlinear system. Reference 17 studied the finite-time stabilization for stochastic nonlinear systems.…”

“…Subsequently, the research on the finite‐time stabilization is getting more and more enriched on account of the development of adding a power integrator technique. A series of results have emerged to manipulate the issues of finite‐time stabilization 13‐29 . For instance, Reference 14 investigated the problem of stochastic high‐order state feedback for the time‐varying delay nonlinear system.…”