Fast Finite-time Consensus Research Articles

Fast Finite-Time Observer-Based Event-Triggered Consensus Control for Uncertain Nonlinear Multiagent Systems with Full-State Constraints.

This article studies a class of uncertain nonlinear multiagent systems (MASs) with state restrictions. RBFNNs, or radial basis function neural networks, are utilized to estimate the uncertainty of the system. To approximate the unknown states and disturbances, the state observer and disturbance observer are proposed to resolve those issues. Moreover, a fast finite-time consensus control technique is suggested in order to accomplish fast finite-time stability without going against the full-state requirements. It is demonstrated that every signal could be stable and boundless, and an event-triggered controller is considered for the saving of resources. Ultimately, the simulated example demonstrates the validity of the developed approach.

A novel finite-time leader-follower consensus control for a disturbed mechanical nonlinear system in presence of actuator saturation

This paper presents a novel leader-follower consensus control for a particular class of nonlinear multi-agent mechanical systems in the presence of control input constraints and external disturbances which includes robot system dynamics with a wide range of potential applications in industry. In this case, one of the agents is selected as the leader to direct the other agents in such a way that the whole system can reach consensus within certain prescribed performance transient bounds. Due to the presence of disturbances in most practical systems, the effect of limited disturbance in the consensus control method has been investigated, and actuator saturation is included in the design process. A terminal sliding mode control method has been adapted to ensure the stability of the overall system and fast finite-time leader-follower consensus control. The simulation results of the multi-agent nonlinear robot system in MATLAB environment, in different scenarios with simultaneous consideration of actuator saturation and external disturbance, will show the efficiency of the proposed control method.

Fast Finite-Time Neuroadaptive Consensus Control for Nonlinear Nontriangular Structured Multiagent Systems With Uncertainty

This literature is concerned with fast finite-time adaptive consensus control for nonlinear nontriangular structured (NTS) multiagent systems (MASs) with uncertainty. In contrast to the existing finite-time schemes, the consensus control for NTS MASs has two design difficulties, reflected in the nonaffine characteristics of the control input and the algebraic loop from the direct backstepping. Moreover, due to the repeated utilization of necessary inequalities, the traditional adaptive framework is incapable of achieving the desired finite-time asymptotic consensus and only rests on satisfying the practical finite-time stability. To tackle such obstacles, a novel adaptive neural algorithm is discussed via the modified tuning function as well as the projection operator in this work. Under the fast finite-time stabilizer constructed, the error of the NTS MASs converges asymptotically to a preset range within the finite time. The flexibility of the algorithm is demonstrated by the simulation example.

Fast Finite-Time Consensus for Multi-agent Systems with Diverse Topologies

Fast Finite-Time Consensus for Multi-agent Systems with Diverse Topologies

Fast Finite-Time Event-Triggered Consensus Control for Uncertain Nonlinear Multiagent Systems With Full-State Constraints

The fast finite-time event-triggered consensus control is investigated for a category of uncertain nonlinear multiagent systems (MASs) with full-state constraints. The uncertainty of the system is estimated by the radial basis function neural networks (RBFNNs). Furthermore, to achieve the fast finite-time stability and not violate the full-state constraints, a fast finite-time event-triggered consensus control method is proposed. The proposed control method can achieve the fast finite-time stability of the system, and all the followers can track the output signal of the leader. Meanwhile, the system states do not exceed the boundaries of the full-state constraints, and the communication resources of the system can be saved. Finally, some simulation examples are provided to verify the feasibility of the proposed approach.

Fast Finite-Time Tracking Consensus With Applications on Multiple Servo Motors

This article focuses on the fast finite-time tracking consensus for uncertain nonlinear multiagent systems. By gracefully combining the hierarchical decomposition, adding a barrier power integrator and disturbance compensation techniques, a new adaptive fast finite-time controller is proposed. Compared with the existing works, the proposed method has several distinguishing features: 1) It can achieve fast finite-time convergence with full state constraints; 2) it can deal with some fully unknown nonlinearities and state-dependent disturbance. Moreover, the nonlinearities can be related with the states of all the followers; 3) the input of the leader is not required to be zero, meaning a broad class of references signals can be generated; and 4) the controller is computationally simply and ready to be implemented. No fuzzy logic/neural networks are needed. Applications of the proposed method on multiple servo motors are also studied.

Fast finite-time consensus protocol of multi-agent systems with nonholonomic constraints

In this paper, a fast finite-time consensus protocol for multi-agent systems with nonholonomic constraints is studied. First, the chained form nonholonomic systems are transformed into two subsystems, which are the first-order subsystem and the reduced-order subsystem. Based on graph theory content and fast finite-time control theory, the fast finite-time consensus problems of the two subsystems are taken into consideration separately. Second, a switching control strategy is proposed to ensure that all states of multiple nonholonomic systems converge instantly to the same state in finite time. Finally, a numerical example is given to verify the effectiveness of the proposed control algorithm.

Adaptive Fault-Tolerant Fast Finite-Time Consensus Protocols for Multiple Mechanical Systems With Output Constraints

In this article, we discuss fast finite-time consensus (FFTC) problems for uncertain nonlinear multiple mechanical systems with actuator faults and time-varying asymmetric output constraints. In order to guarantee the constraints are satisfied, an appropriate nonlinear mapping (NM) is employed to transform the original system with output constrains into an corresponding unconstrained one. Combining neural networks technology, graph theory, fast finite-time control theory, and backstepping technology, the actuator faults are considered to propose a distributed adaptive finite-time consensus (FTC) protocol, which can guarantee the position errors as well as the velocity errors reaching a region in finite time. Finally, an illustrative example is presented to support the obtained theoretical results.

Distributed Fast Finite-Time Tracking Consensus of Multi-Agent Systems With a Dynamic Leader

Distributed fast finite-time tracking consensus (FTTC) is investigated for first-order nonlinear multi-agent systems (MASs), where the leader has an external input unknown to all followers. Based on global finite-time stability and Lyapunov stability, two distributed tracking protocols are proposed to guarantee fast FTTC. First, a basic distributed non-smooth protocol for solving this problem is proposed and analyzed. A limitation of the designed protocol is that the control gains should depend on some global information like the spectrum of Laplacian matrix. To remove this limitation, a fully distributed protocol is further designed and analyzed. Theoretical studies imply that the states of the considered MASs will also achieve fast FTTC. Finally, two simulation examples are performed on Chua’s circuit system to verify the theoretical results.

Adaptive Practical Fast Finite-Time Consensus Protocols for High-Order Nonlinear Multi-Agent Systems With Full State Constraints

This paper mainly addresses the issue of fast finite-time consensus (FTC) algorithms for a group of high-order uncertain nonlinear non-strict-feedback Multi-agent Systems (MASs) with time-varying asymmetric full state constraints. In order to guarantee the state constraints are satisfied, an appropriate asymmetric nonlinear mapping (NM) is employed to transform the original full state constrained system into a corresponding unconstrained one. Combining neural networks technology, graph theory, fast finite-time control theory and backstepping recursive design scheme, the uncertainties and non-strict-feedback form are considered to propose a distributed adaptive FTC protocol which can guarantee tracking error reaching a region in finite time. Finally, an example is given to show that the designed control law can perform effective control.

Fast finite-time tracking control for multi-agent systems with mismatched disturbances under directed communication graphs

In this paper, the fast finite-time consensus problem on multi-agent systems is considered. Multi-agent systems are affected by mismatched disturbances and the communication graph is directed. By a sliding mode observer and a fast nonsingular terminal sliding mode control method, the feedforward-feedback controller is presented for multiple second-order systems and multiple high-order systems to achieve consensus, respectively. The proposed control method can provide short convergence time and improved control input without strong chattering and singularity phenomenon. Finally, simulations are given to verify the availability of the methods.

Adaptive practical fast finite-time consensus protocols for multiple uncertain nonlinear mechanical systems

In this paper, we study the design of a fast finite-time consensus protocol for multiple nonlinear mechanical systems with uncertainties and disturbance. Combining the theories of finite-time control and algebraic graph, a distributed adaptive fast finite-time consensus protocol is proposed in a recursive design way. In the designed control scheme, the unknown nonlinear functions are modelled by neural networks. With the help of fast finite-time boundedness lemma, the practical finite-time consensus of the multiple mechanical systems is proved. In the end, the validity of the proposed protocol is confirmed by a numerical example of multiple manipulators.

Adaptive neural consensus tracking control for a class of 2-order multi-agent systems with nonlinear dynamics

This paper investigates the problem of finite-time consensus tracking control for a class of 2-order nonlinear multi-agent systems (MASs). In order to present a consensus control protocol by adaptive neural control approach, a novel fast finite-time stability criterion is first set up, which provides a theoretical basis for applying approximation-based adaptive control approaches to solve the finite-time control issues. Furthermore, an adaptive neural fast finite-time consensus tracking controller is constructed based on the developed finite-time stability criterion. The suggested adaptive neural backstepping control design scheme successfully avoids the problem of singularity of controllers. Under the action of the presented protocol, the output of each follower tracks the reference signal and other signals of the closed-loop system remain bounded in finite time. The efficacy of the proposed control scheme is confirmed by simulation study.

Adaptive Fast Finite-Time Consensus for Second-Order Uncertain Nonlinear Multi-Agent Systems With Unknown Dead-Zone

This paper presents an adaptive fast finite-time consensus (FTC) for second-order uncertain nonlinear (UN) multi-agent systems (MASs) with unknown nonsymmetric dead-zone and external disturbances. In the process of control protocols design, based on the estimation of the dead-zone width that is obtained by using adaptive method, a fuzzy logic dead-zone compensator is adopted to deal with the nonsymmetric dead-zone input phenomenon. Combining finite-time control technique and Lyapunov's relevant theory, a new fast FTC protocol is developed. Based on the basis of radial basis function neural networks (RBFNNs) theories, the unknown nonlinear functions are approximated. Under the presented consensus protocols and adaptive laws, it can be proved that the position errors of arbitrary two agents can reach a small region of zero in finite time as well as the velocity errors. Ultimately, the effectiveness of the designed method is tested via two numerical examples.

Fast terminal sliding mode control for a nonlinear multi-agent robot system with disturbance

This paper addresses the consensus control problem for a nonlinear multi-agent robot system in the presence of external disturbances. Robot system is one of the most important practical systems in the industry. Because of the presence of disturbances in most practical systems, this paper considers the issue of finite-time consensus control of the nonlinear multi-agent robot system in the presence of unknown bounded disturbance. The modified terminal sliding mode control method is suggested for the system which is able to guarantee the stability of the overall system and fast finite-time consensus control purpose. In two different scenarios, the simulation of multi-agent robot system has been performed. The results show the effectiveness of the proposed control method on the multi-agent robot system.

A fast clock synchronization algorithm for wireless sensor networks

This paper proposes a novel clock synchronization algorithm for wireless sensor networks (WSNs). The algorithm is derived using a fast finite-time average consensus idea, and is fully distributed, meaning that each node relies only on its local clock readings and reading announcements from its neighbours. For networks with an acyclic graph, the algorithm converges in only d iterations for clock rate synchronization and another d iterations for clock offset synchronization, where d is the graph diameter. The algorithm enjoys low computational and communicational complexities and robustness against transmission adversaries. Each node can execute the algorithm asynchronously without the need for global coordination. Due to its fast convergence, the algorithm is most suitable for large-scale WSNs. For WSNs with a cyclic graph, a fast distributed depth-first-search (DFS) algorithm can be applied first to form a spanning tree before applying the proposed synchronization algorithm.

Fast Finite-Time Consensus Tracking of Second-Order Multi-Agent Systems with a Virtual Leader

Fast Finite-Time Consensus Tracking of Second-Order Multi-Agent Systems with a Virtual Leader

Fast Finite-Time Consensus Tracking of Heterogeneous Multi-Agent Systems with a Virtual Leader

This paper proposes a novel finite-time consensus tracking protocol for guaranteeing heterogeneous multi-agent systems with a virtual leader to achieve the fast finite-time consensus tracking. The Lyapunov function method, algebra graph theory, homogeneity with dilation and some other techniques are employed to prove that heterogeneous multi-agent systems with a virtual leader applying the proposed protocol can reach the finite-time consensus tracking. Numerical simulations indicate that compared with traditional finite-time consensus tracking protocols, the proposed protocol can accelerate the convergence speed of the finite-time consensus tracking.

Fast Finite-Time Consensus Tracking of First-Order Multi-Agent Systems with a Virtual Leader

This paper proposes a novel finite-time consensus tracking protocol for guaranteeing first-order multi-agent systems with a virtual leader to achieve the fast finite-time consensus tracking. The Lyapunov function method, algebra graph theory, homogeneity with dilation and some other techniques are employed to prove that first-order multi-agent systems with a virtual leader applying the proposed protocol can reach the finite-time consensus tracking. Furthermore, theoretical analysis and numerical simulations show that compared with the traditional finite-time consensus tracking protocols, the proposed protocol can accelerate the convergence speed of achieving the finite-time consensus tracking.

Multi-surface sliding control for fast finite-time leader-follower consensus with high order SISO uncertain nonlinear agents

SUMMARY In this paper, multi surface sliding cooperative control scheme is presented and new multiple sliding surfaces are proposed. It is proven that, for the setup that each agent is described by a chain of integrators, where the last integrator is perturbed by a bounded disturbance, leader–follower consensus can be achieved on these sliding surfaces if the communication graph has a directed spanning tree. Also, sliding variables can be driven to the sliding surfaces in fast finite time by the nonsmooth control law. The fast finite-time Lyapunov stability theorem, the terminal sliding control technique, and the adding a power integrator design approach are used in our proposed control. Simulation results demonstrate the effectiveness of the proposed scheme. Copyright © 2013 John Wiley & Sons, Ltd.