Event-Based Adaptive Fixed-Time Fuzzy Control for Active Vehicle Suspension Systems With Time-Varying Displacement Constraint

Liu

et al. 2021

Self Cite

In this article, the command filter based adaptive event-triggered control problem for multiple-input and multiple-output multiple time-delay stochastic nonlinear systems is considered. First, a state observer is constructed to estimate the unmeasured states of systems. Then, in the framework of backstepping design, the command filtered and event-triggered techniques are employed to avoid the problem of "explosion of complexity" and save the communication resources, respectively. Meanwhile, by utilizing the command filters, a novel variable separation method is constructed to address the algebraic-loop problem, which caused by the nonstrict-feedback item. The boundedness of the whole signals in systems can be remained, and the given desired trajectories can be followed by the system outputs. Finally, a numerical example is shown to demonstrate the effectiveness of the proposed control method.

Section: Introductionmentioning

confidence: 99%

Command filtered event‐triggered adaptive control for MIMO stochastic multiple time‐delay systems

Zhu

Liu

et al. 2021

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“…Two kinds of novel functions have been designed, where the developed switching function can deal with the singularity problem cause by adaptive fixed-time controller, and the stability analysis of adaptive fixed-time output-feedback control can be achieved by designing a continuous hyperbolic tangent function. Further works will concentrate on the event-triggered control issues [42][43][44][45][46][47] due to the requirement of cooperative control for multi-AUVs under limited communication bandwidth.…”

Section: Discussionmentioning

confidence: 99%

Singularity avoidance adaptive output‐feedback fixed‐time consensus control for multiple autonomous underwater vehicles subject to nonlinearities

Xue

et al. 2022

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This article investigates the singularity avoidance adaptive output-feedback fixed-time consensus control problem for multiple autonomous underwater vehicles (AUVs) subject to nonlinearities. A distributed state observer is designed to reconstruct the unmeasurable coupling states of each AUV system.In order to handle the unknown nonlinearities of the multi-AUV systems, the fuzzy logic systems are adopted to approximate unknown hydrodynamic parameters. By combining adaptive fixed-time control with backstepping technology, an adaptive singularity avoidance fixed-time consensus control algorithm is developed, where a new error switching mechanism is designed for avoiding the singularity problem caused by the differentiation of the virtual control law. Subsequently, a singularity avoidance distributed adaptive output-feedback fixed-time fuzzy controller is presented, under which an auxiliary function is designed to handle the difficulty of the fixed-time stability analysis under the output-feedback control strategy, where two types of observer errors are needed in the designed Lyapunov function to achieve the fixed-time stability. Then, based on the fixed-time stability criterion, it is proved that both the consensus tracking performance and the closed-loop stability can be guaranteed in fixed time. Finally, a simulation example verifies the effectiveness of the developed control strategy.

“…

M

is the number of fuzzy rules,

{\psi}_n^c

and

{\overline{\omega}}^c

are fuzzy sets. According to References 43‐45, the FLSs can be written as

y(x)=\frac{\sum \limits_{c=1}^M{\nu}_c{\Pi}_{i=1}^n{\eta}_{\psi_i^c}\left({x}_i\right)}{\sum \limits_{c=1}^M\left(\prod \limits_{i=1}^n{\eta}_{\psi_i^c}\left({x}_i\right)\right)},

where

x={\left[{x}_1,\dots, {x}_n\right]}^T

{\nu}_c={\max}_{y\in R}{\eta}_{{\overline{\omega}}^c}(y)

{\eta}_{\psi_i^c}\left({x}_i\right)

...…”

Section: The Formulation Of the Problemmentioning

confidence: 99%

Fixed‐time adaptive anti‐disturbance and fault‐tolerant control for multi‐agent systems

Xue

2022

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This article investigates the fixed‐time adaptive anti‐disturbance and fault‐tolerant control problem for a class of nonlinear multi‐agent systems with non‐affine nonlinear faults. A simplified backstepping approach is presented that only requires designing one Lyapunov function for high‐order multi‐agent systems, which reduces the computational burden. By designing a new compound observer, an anti‐disturbance and fault‐tolerant control strategy is developed to estimate and compensate the compound nonlinear terms composed of external disturbances and nonlinear faults. In addition, an auxiliary control variable is designed to solve the problem of “explosion of complexity” and ensure the system stability in a fixed time. Based on the Lyapunov stability method, it is proved that the nonlinear multi‐agent systems are semi‐global practical fixed‐time stable. Finally, the effectiveness of the proposed control strategy is verified by some simulation results.