scholarly journals Adaptive Fixed-time Control for Nonlinear Systems Against Time-varying Actuator Faults

2021 ◽  
Author(s):  
Yu Mei ◽  
Jing Wang ◽  
Ju H. Park ◽  
Kaibo Shi ◽  
Hao Shen
Keyword(s):  
Nonlinear Systems ◽  
Fault Tolerant ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Fixed Time ◽  
Time Interval ◽  
Time Varying ◽  
Actuator Faults ◽  
Time Control ◽  
Control Scheme

Abstract The adaptive fixed-time control problem for nonlinear systems with time-varying actuator faults is investigated in this paper. A novel adaptive fixed-time controller is designed via combining the Lyapunov stability theory with the backstepping method. It can be adapted to both system uncertainties and unknown actuator faults. Compared with the existing fault-tolerant control schemes subject to actuator faults, the adaptive fixed-time neural networks control scheme can make sure that the tracking error is convergent in a small neighborhood of the origin within a fixed-time interval, and it does not depend on the original states of the system and actuator faults. In light of the control scheme proposed in this paper, the fixed-time stability of the closed-loop system can be guaranteed by theoretical analysis, and a numerical example is provided to verify the effectiveness of obtained theoretical results.

Adaptive finite-time control for stochastic nonlinear systems using multi-dimensional Taylor network

2021 ◽  
pp. 014233122110396
Author(s):  
Shan-Liang Zhu ◽  
Ming-Xin Wang ◽  
Yu-Qun Han
Keyword(s):  
Nonlinear Systems ◽  
Finite Time ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Lyapunov Stability Theory ◽  
Loop System ◽  
Stochastic Nonlinear Systems ◽  
Time Control ◽  
Control Scheme ◽  
The Stability

In this paper, the problem of adaptive finite-time multi-dimensional Taylor network (MTN) control for a class of stochastic nonlinear systems is investigated. By combining the MTN-based approximate method and adaptive backstepping technique, a novel adaptive finite-time MTN control scheme is proposed. In this scheme, the MTNs are used to approximate the unknown nonlinear functions of the systems. The finite-time Lyapunov stability theory is utilized to prove the stability of the close-loop system. The proposed scheme can ensure that all signals in the closed-loop system are bounded in probability and the tracking error converges to a small neighborhood of the origin in a finite time. Three simulation examples are presented to show the effectiveness of the control scheme. It should be pointed that the adaptive MTN controller proposed in this paper has the advantages of fast computational speed and good real-time performance thanks to the simple structure of the MTN.

scholarly journals Neural networks-based adaptive finite-time control of switched nonlinear systems under time-varying actuator failures

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Xikui Liu ◽  
Xiurong Shi ◽  
Yan Li
Keyword(s):  
Neural Networks ◽  
Nonlinear Systems ◽  
Finite Time ◽  
Fault Tolerant ◽  
Tracking Error ◽  
Adaptive Controller ◽  
Time Varying ◽  
Switched Nonlinear Systems ◽  
Actuator Failures ◽  
Time Control

AbstractThis paper is dedicated to neural networks-based adaptive finite-time control design of switched nonlinear systems in the time-varying domain. More specifically, by employing the approximation ability of neural networks system, an integrated adaptive controller is constructed. The main aim is to make sure the closed-loop system in arbitrary switching signals is semi-global practical finite-time stable (SGPFS). A backstepping design with a common Lyapunov function is proposed. Unlike some existing control schemes with actuator failures, the key is dealing with the time-varying fault-tolerant job for the switched system. It is also proved that all signals in the system are bounded and the tracking error can converge in a small field of the origin in finite time. A practical example is presented to illustrate the validity of the theory.

scholarly journals Fixed-Time Sliding-Mode Fault-Tolerant Control of Waste Heat Power Generator Systems

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Zhi Wang ◽  
Yateng Bai ◽  
Jin Xie ◽  
Zhijie Li ◽  
Caoyuan Ma ◽  
...  
Keyword(s):  
Fault Tolerant ◽  
Waste Heat ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
Tracking Error ◽  
Fixed Time ◽  
Fault Estimation ◽  
Actuator Fault ◽  
Heat Power ◽  
Time Control

In order to overcome disturbances such as the instability of internal parameters or the actuator fault, the time-varying proportional-integral sliding-mode surface is defined for coordinated control of the excitation generator and the steam valve of waste heat power generation units, and a controller based on sliding-mode function is designed which makes the system stable for a limited time and gives it good performance. Based on this, a corresponding fault estimation law is designed for specific faults of systems, and a sliding-mode fault-tolerant controller is constructed based on the fixed-time control theory so that the systems can still operate stably when an actuator fault occurs and have acceptable performance. The simulation results show that the tracking error asymptotically tends to be zero, and the fixed-time sliding-mode fault-tolerant controller can obviously improve the dynamic performance of the system.

scholarly journals Adaptive Fixed-Time Sliding Mode Control for Uncertain Twin-Rotor System with Experimental Validation

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Linwu Shen ◽  
Qiang Chen ◽  
Meiling Tao ◽  
Xiongxiong He
Keyword(s):  
Sliding Mode ◽  
Setting Time ◽  
Tracking Error ◽  
Fixed Time ◽  
External Disturbances ◽  
Rotor Systems ◽  
Time Control ◽  
Control Scheme ◽  
Comparative Results ◽  
Twin Rotor

This paper proposes an adaptive fixed-time control scheme for twin-rotor systems subject to the inertia uncertainties and external disturbances. First of all, a fixed-time sliding mode surface is constructed and the corresponding controller is developed such that the fixed-time uniform ultimate boundedness of the sliding variable and tracking error could be guaranteed simultaneously, and the setting time is independent of the initial values. The adaptive update laws are developed to estimate the upper bounds of the lumped uncertainties and external disturbances such that no prior knowledge on the system uncertainties and disturbances is required. Finally, a twin-rotor platform is constructed to verify the effectiveness of proposed scheme. Comparative results show better position tracking performance of the proposed control scheme.

scholarly journals Adaptive Fixed-Time Control of Strict-Feedback High-Order Nonlinear Systems

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 963
Author(s):  
Yang Li ◽  
Jianhua Zhang ◽  
Xiaoyun Ye ◽  
Cheng Siong Chin
Keyword(s):  
Nonlinear Systems ◽  
Fixed Time ◽  
High Order ◽  
Convergence Time ◽  
Feedback Form ◽  
Time Control ◽  
Control Scheme ◽  
Lyapunov Stability Criterion ◽  
The Stability ◽  
Strict Feedback

This paper examines the adaptive control of high-order nonlinear systems with strict-feedback form. An adaptive fixed-time control scheme is designed for nonlinear systems with unknown uncertainties. In the design process of a backstepping controller, the Lyapunov function, an effective controller, and adaptive law are constructed. Combined with the fixed-time Lyapunov stability criterion, it is proved that the proposed control scheme can ensure the stability of the error system in finite time, and the convergence time is independent of the initial condition. Finally, simulation results verify the effectiveness of the proposed control strategy.

Finite-time backstepping control with command filter for a class of nonlinear systems with parametric uncertainties

2020 ◽  
Vol 42 (12) ◽  
pp. 2297-2307 ◽  
Author(s):  
Cong Feng ◽  
Qing Wang ◽  
Changhua Hu ◽  
Shen Zhang
Keyword(s):  
Nonlinear Systems ◽  
Finite Time ◽  
Error Compensation ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Backstepping Control ◽  
Parametric Uncertainties ◽  
Compensation Mechanism ◽  
Time Control ◽  
Command Filter

In this paper, the problem of adaptive finite-time control is considered for a class of nonlinear systems with parametric uncertainties. A novel adaptive command filtered backstepping control method is proposed, and the adverse impact caused by the command filter is eliminated by introducing modified error compensation mechanism with consideration of parametric uncertainties. Combined with the designed adaptation laws, the error compensation mechanism can be finite-time stable. Rigorous proof is achieved to show that the tracking error converges to a small neighborhood of zero in finite time with online parameters adaptation and error compensation. Finally, numeral simulations are presented to validate the effectiveness of the proposed adaptive finite-time control scheme.

Adaptive tracking control of stochastic nonlinear systems with unknown time-varying powers

2021 ◽  
pp. 014233122098223
Author(s):  
Huijuan Li ◽  
Wuquan Li ◽  
Jianzhong Gu
Keyword(s):  
Nonlinear Systems ◽  
Design Method ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Adaptive Controller ◽  
Upper And Lower Bounds ◽  
Stochastic Nonlinear Systems ◽  
Time Varying ◽  
Adaptive Tracking Control ◽  
Output Tracking

This paper investigates the adaptive output tracking problem for a class of high-order stochastic nonlinear systems with unknown time-varying powers and nonlinear parameterized uncertainties. By using the parameter separation technique and adding a power integrator design method, an adaptive controller with upper and lower bounds of the unknown time-varying power is successfully designed to guarantee that all the states of the closed-loop system are bounded in probability and the output tracking error can be regulated into a small neighborhood of the origin in probability. Finally, a simulation example is provided to illustrate the effectiveness of the designed controllers.

scholarly journals Fixed-time output tracking control for extended nonholonomic chained-form systems with state observers

2020 ◽  
Vol 53 (3-4) ◽  
pp. 400-408 ◽  
Author(s):  
Hua Chen ◽  
Huilin Li ◽  
YiWen Yang ◽  
Lulu Chu
Keyword(s):  
Tracking Control ◽  
Estimation Error ◽  
Tracking Error ◽  
Fixed Time ◽  
Structure Characteristic ◽  
Initial State ◽  
Time Control ◽  
Output Tracking Control ◽  
State Observers ◽  
Control Scheme

This paper deals with the fixed-time tracking control problem of extended nonholonomic chained-form systems with state observers. According to the structure characteristic of such chained-form systems, two subsystems are considered to design controllers, respectively. First of all, using the fixed-time control theory, a controller is proposed to make the first tracking error subsystem converge to zero in bounded time independent initial state. Second, a state observer is proposed to estimate the unmeasurable states of the second subsystem. And the precise state estimation can be presented from the observer within finite time; moreover, the upper bound of time is a constant independent on the initial estimation error. Third, a fixed-time controller is designed to drive all states of the second chained-form subsystem to zero within pre-calculated time. Finally, the effectiveness of the proposed control scheme is validated by simulation results.

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