Practical Adaptive Fuzzy Control of Nonlinear Pure-Feedback Systems With Quantized Nonlinearity Input

Summary This paper focuses on the problem of disturbance attenuation with fast global finite‐time convergence (FTC) for a class of generalized high‐order uncertain nonlinear systems. Combining the fast finite‐time stabilization technique with a delicate manipulation of sign functions, a new control approach is proposed to attenuate the serious uncertainties substantially, including time‐varying control coefficients, nonlinear parameters, and external disturbances, while achieving the performance evaluated in terms of L2‐L2p gain. A notable feature of the control strategy is the fast FTC, which greatly shortens the convergent time when the initial state is far away from the origin. A numerical example is provided to demonstrate the effectiveness of the proposed method.

Section: Resultsmentioning

confidence: 99%

“…Recently, some new design methods of tracking control and adaptive stabilization have been proposed in related works. [44][45][46][47][48][49][50] Inspired by these interesting results, several future investigation directions include as follows. (i) Is it possible to design a fast finite-time tracking controller with a fast tracking effort?…”

Section: Resultsmentioning

confidence: 99%

Disturbance attenuation with fast global finite‐time convergence for generalized high‐order uncertain nonlinear systems

Sun

Wang

Chen

et al. 2019

“…Therefore, nonlinear control can be seen as a hot active topic due to its theoretical and practical significance. In recent years, great achievements have been obtained in nonlinear control area, including adaptive control, [1][2][3][4][5] neural network (NN) control, [6][7][8] and finite-time control. [9][10][11][12][13] Among these results, finite-time control has attracted considerable attention because of its remarkable advantages including fast convergence and high accuracy.…”

Section: Introductionmentioning

confidence: 99%

Finite‐time adaptive control of high‐order nonlinear systems with unknown control coefficients and actuator fault

Park

2020

In this article, the global finite-time adaptive control problem is considered for high-order nonlinear systems in the presence of unknown control coefficients, actuator fault, and external disturbance. Different from the previous results, a tune parameter is introduced to directly compensate the unknown control coefficients rather than the traditional Nussbaum-gain function. Without requiring a priori knowledge of the uncertainties, a switching-type adaptive controller is proposed by adding a power integrator method. Based on the modified switching mechanism, the controller parameter can be tuned online such that global finite-time stability can be achieved. Finally, a simulation example combined with comparison is provided to verify the effectiveness of the proposed method.

“…[9][10][11][12][13] However, stochastic phenomenon always exists in nonlinear systems and effects nonlinear systems' stability. To overcome this problem, backstepping control approach [14][15][16][17][18][19][20][21][22] was introduced to handle the problem of stabilization. Therefore, the control design of nonlinear stochastic systems has attracted more and more attention in recent years.…”

Section: Introductionmentioning

confidence: 99%

Observer‐based adaptive control for nonlinear strict‐feedback stochastic systems with output constraints

Liang

et al. 2018

In this paper, an adaptive output-feedback control problem is investigated for nonlinear strict-feedback stochastic systems with input saturation and output constraint. A barrier Lyapunov function is used to solve the problem of output constraint. Then, fuzzy logic systems are used to approximate the unknown nonlinear functions, and a fuzzy state observer is designed to estimate the unmeasured states. To overcome the difficulties in designing the control signal in the saturation, we introduce an auxiliary signal in the n + 1th step in the deduction. By combining Nussbaum technique and the adaptive backstepping technique, an adaptive output-feedback control method is developed. The proposed control method not only overcomes the problem of the compensation for the nonlinear term from the input saturation but also overcomes the problem of unavailable state measurements. It is proved that all the signals of the closed-loop system are semiglobally uniformly ultimately bounded. Finally, the effectiveness of the proposed method is verified by the simulation results.