scholarly journals Distributed Adaptive Fixed-Time Tracking Consensus Control for Multiple Uncertain Nonlinear Strict-Feedback Systems under a Directed Graph

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Pinwei Li ◽  
Jiyang Dai ◽  
Jin Ying ◽  
Zhe Zhang ◽  
Cheng He
Keyword(s):  
Directed Graph ◽  
Control Strategy ◽  
Design Procedure ◽  
Fixed Time ◽  
Convergence Time ◽  
Approximation Technique ◽  
Feedback Systems ◽  
Consensus Control ◽  
Consensus Tracking ◽  
Strict Feedback

In this brief, we study the distributed adaptive fixed-time tracking consensus control problem for multiple strict-feedback systems with uncertain nonlinearities under a directed graph topology. It is assumed that the leader’s output is time varying and has been accessed by only a small fraction of followers in a group. The distributed fixed-time tracking consensus control is proposed to design local consensus controllers in order to guarantee the consensus tracking between the followers and the leader and ensure the error convergence time is independent of the systems’ initial state. The function approximation technique using radial basis function neural networks (RBFNNs) is employed to compensate for unknown nonlinear terms induced from the controller design procedure. From the Lyapunov stability theorem and graph theory, it is shown that, by using the proposed fixed-time control strategy, all signals in the closed-loop system and the consensus tracking errors are cooperatively semiglobally uniformly bounded and the errors converge to a neighborhood of the origin within a fixed time. Finally, the effectiveness of the proposed control strategy has been proved by rigorous stability analysis and two simulation examples.

Command filtered backstepping tracking control of uncertain nonlinear strict-feedback systems under a directed graph

2016 ◽  
Vol 39 (7) ◽  
pp. 1027-1036 ◽  
Author(s):  
Yi Zhang ◽  
Guozeng Cui ◽  
Guangming Zhuang ◽  
Junwei Lu ◽  
Ze Li
Keyword(s):  
Directed Graph ◽  
Tracking Control ◽  
Design Procedure ◽  
Design Parameters ◽  
Feedback Systems ◽  
Consensus Tracking ◽  
Backstepping Approach ◽  
Non Linear ◽  
Distributed Controllers ◽  
Strict Feedback

This paper studies the distributed consensus tracking control problem of multiple uncertain non-linear strict-feedback systems under a directed graph. The command filtered backstepping approach is utilised to alleviate computation burdens and construct distributed controllers, which involves compensated signals eliminating filtered error effects in the design procedure. Neural networks are employed to estimate uncertain non-linear items. Using a Lyapunov stability theorem, it is proved that all signals in the closed-looped systems are semi-globally uniformly ultimately bounded. In addition, consensus errors converge to a small neighbourhood of the origin by adjusting the appropriate design parameters. Finally, simulation results are presented to demonstrate the effectiveness of the developed control design approach.

scholarly journals Adaptive Fixed-Time Tracking Consensus Control for Multiagent Nonlinear Pure-Feedback Systems with Performance Constraints

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Pinwei Li ◽  
Jiyang Dai ◽  
Jin Ying
Keyword(s):  
Fixed Time ◽  
Mean Value ◽  
High Order ◽  
Mean Value Theorem ◽  
Feedback Systems ◽  
Feedback Form ◽  
Consensus Control ◽  
Performance Constraints ◽  
Whole Process ◽  
Constraint Variable

This paper investigates adaptive fixed-time tracking consensus control problems for multiagent nonlinear pure-feedback systems with performance constraints. Compared with existing results of first/second/high-order multiple agent systems, the studied systems have more complex nonlinear dynamics with each agent being modeled as a high-order pure-feedback form. The mean value theorem is introduced to address the problem of nonaffine structure in nonlinear pure-feedback systems. Meanwhile, radial basis function neural networks (RBFNNs) are employed to approximate unknown functions. Furthermore, a constraint variable is used to guarantee that all local tracking errors are within the prescribed boundaries. It is shown that, by utilizing the proposed consensus control protocol, each tracking consensus error can converge into a neighborhood around zero within designed fixed time, the tracking consensus performance can be ensured during the whole process, and all signals in the investigated systems are bounded. Finally, two simulations are performed and the results demonstrate the effectiveness of the proposed control strategy.

scholarly journals Leader-Follower Fixed-Time Group Consensus Control of Multiagent Systems under Directed Topology

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Yilun Shang ◽  
Yamei Ye
Keyword(s):  
Distributed Control ◽  
Multiagent Systems ◽  
Initial Conditions ◽  
Fixed Time ◽  
Local Information ◽  
Convergence Time ◽  
Group Consensus ◽  
Consensus Control ◽  
Directed Topology ◽  
Theoretical Results

This paper investigates the fixed-time group consensus problem for a leader-follower network of integrators with directed topology. A nonlinear distributed control protocol, based on local information, is proposed such that the follower agents in each subgroup are able to track their corresponding leaders in a prescribed convergence time regardless of the initial conditions. Simulation examples are presented to demonstrate the availability of our theoretical results.

scholarly journals Event-Triggered Adaptive Backstepping Control for Strict-Feedback Nonlinear Systems with Zero Dynamics

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Bo Xu ◽  
Xiaoping Liu ◽  
Huanqing Wang ◽  
Yucheng Zhou
Keyword(s):  
Measurement Errors ◽  
Closed Loop ◽  
Control Strategies ◽  
Design Procedure ◽  
Adaptive Controller ◽  
Zero Dynamics ◽  
Feedback Systems ◽  
Adaptive Backstepping ◽  
Event Triggered ◽  
Strict Feedback

This paper focuses on the problem of event-triggered control for a class of uncertain nonlinear strict-feedback systems with zero dynamics via backstepping technique. In the design procedure, the adaptive controller and the triggering event are designed at the same time to remove the assumption of the input-to-state stability with respect to the measurement errors. Besides, we propose an assumption to deal with the problem of zero dynamics. Three different event-triggered control strategies are designed, which guarantees that all the closed-loop signals are globally bounded. The effectiveness of the proposed methods is illustrated and compared using simulation examples.

scholarly journals Fixed-Time Observer Based Prescribed-Time Containment Control of Unmanned Underwater Vehicles with Faults and Uncertainties

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4515 ◽  
Author(s):  
Tingting Yang ◽  
Shuanghe Yu
Keyword(s):  
Control Strategy ◽  
Fixed Time ◽  
Underwater Vehicles ◽  
Convergence Time ◽  
Control Input ◽  
Containment Control ◽  
Unmanned Underwater Vehicles ◽  
Time Control ◽  
Intermediate Variables ◽  
Uniformly Bounded

The problem of prescribed-time containment control of unmanned underwater vehicles (UUVs) with faults and uncertainties is considered. Different from both regular finite-time control and fixed-time control, the proposed prescribed-time control strategy is built upon a novel coordinate transformation function and the block decomposition technique, resulting in the followers being able to move into the convex hull spanned by the leaders in prespecifiable convergence time. Moreover, intermediate variables and the control input terms are also shown to remain uniformly bounded at the prescribed-time. To reduce the magnitude of the bounds, a novel fixed-time observer for the fault is proposed. Two numerical examples are provided to verify the effectiveness of the proposed prescribed-time control strategy.

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