Leader-following Consensus Control Research Articles

Event-triggered-based encoding–decoding consensus control of continuous-time multi-agent systems under DoS attacks

The security of multi-agent systems (MASs) is important particularly when considering the potential threat posed by malicious attackers. Specifically, network attacks and information theft caused by attackers have garnered significant attention due to their potential to destroy the consensus of the system. Therefore, this paper presents a novel approach to achieve leader-following consensus control of continuous-time MASs under DoS attacks, leveraging event-triggered encoding and decoding techniques. When the DoS attacks occur, the transmitted information between agents becomes unavailable. To address this challenge, a buffer is introduced to store the latest transmission data and then the stored data can be used when the DoS attacks exist. We also propose an event-triggered encoding–decoding strategy that can be employed for privacy protection in linear continuous-time MASs. The transmitted data is encoded as a codeword before transmitting, and the encoder updates it when event-triggered conditions are met. The receiving end decodes the data upon receipt. Furthermore, a distributed switching controller is designed using the encoded and stored state values to achieve leader-following consensus. The control gain is calculated to obtain sufficient conditions for DoS attacks through the linear matrix inequalities (LMI) and Lyapunov functions. The boundedness of transmitted data and the Zeno phenomenon are also analyzed. Finally, numerical simulations are conducted to demonstrate the effectiveness of the proposed control algorithm.

On Generalized Homogeneous Leader-Following Consensus Control for Multiagent Systems

On Generalized Homogeneous Leader-Following Consensus Control for Multiagent Systems

Leader-following Non-fragile Consensus Control of Fuzzy Multi-agent Fractional Order Interval Systems

Leader-following Non-fragile Consensus Control of Fuzzy Multi-agent Fractional Order Interval Systems

Failure-distribution-dependent leader-following fault-tolerant consensus for multiagent system with cyberattacks

This article concentrates on a failure-distribution-dependent leader-following fault-tolerant consensus control for multiagent systems with cyberattacks. First, considering the characteristic of failures, a failure distribution model which is more in line with the actual situation is established. To reduce the influence of zero initial conditions, an [Formula: see text] performance index suitable for leader-following multiagent systems is constructed. After this, it is difficult to obtain the augmented form of the closed-loop system due to the coupling of parameters caused by cyberattacks. Thus, based on the provided failure model and performance index, a new fault-tolerant controller is designed by using topological structure segmentation to satisfy the leader-following multiagent system fault-tolerant consensus. Finally, a numerical example is shown to prove the feasibility of this algorithm.

Prescribed-time leader-following consensus and containment control for second-order multiagent systems with only position measurements

The problems of prescribed-time leader-following consensus and prescribed-time containment control for double-integrator multiagent systems (MASs) with only position measurements are investigated in this paper. An observer-based prescribed-time control protocol is proposed, in which the two groups of observers for estimating the consensus errors of each follower both converge to zero within a specified time. Furthermore, the proposed controller only relies on its own observers and does not need to obtain the data from observers embedded in its neighbor nodes. The sufficient conditions for the MASs to achieve the defined prescribed-time consensus and to fulfill the goal of prescribed-time containment control are, respectively, given. The effectiveness of the proposed control protocol is further verified by computer simulations.

Leader-following consensus control for nonlinear multiagent systems with unknown time-varying measurement sensitivity and infinite communication delays

This paper investigates the consensus problem for nonlinear multiagent systems (MASs) with unknown time-varying measurement sensitivity and infinite communication delays. Unlike existing works, the output measurement sensitivity is described as time-varying, and an infinite communication delay is considered between the agents. Under this condition, a novel output feedback control algorithm is developed. First, based on the hierarchical technique and Lyapunov-based time-domain method, the high-gain compensator and observer are constructed to tolerate the effect of infinite communication delays and accurately estimate the state of the leader. Subsequently, a new distributed k-filter and output feedback controller are proposed, which not only further relax the traditional Lipschitz conditional conservatism but also greatly simplify the design process. It is proved that the closed-loop system is globally stable and all agents can achieve consensus. Finally, the effectiveness of the proposed method is verified through the simulation of the single-link manipulators.

Fully Distributed Event-Triggered Anti-Windup Consensus of Heterogeneous Systems With Input Saturation and an Active Leader.

This article addresses the event-based fully distributed consensus problem for linear heterogeneous multiagent systems (MASs) subject to input saturation. A leader with unknown but bounded control input is also considered. Based on an adaptive dynamic event-triggered protocol, all the agents can reach output consensus without knowing any global knowledge. Moreover, by applying a multiple-level saturation technique, the input-constrained leader-following consensus control is achieved. The given event-triggered algorithm can be utilized for the directed graph containing a spanning tree with the leader as the root. One distinct feature compared with previous works is that the proposed protocol can achieve saturated control without any a priori condition, instead, the local information is needed. Finally, the numerical simulations are illustrated to verify the performance of the proposed protocol.

Cooperative Operation Control of Virtual Coupling High-Speed Trains With Input Saturation and Full-State Constraints

In this paper, the distributed cooperative control of virtual coupling high-speed trains (HSTs) subject to full-state constraints, actuator limitations, dynamical uncertainties and environmental disturbances is investigated. Targeting at the full-state constraints in cooperative operation of HSTs, a distributed nonlinear state-dependent function (DNSDF) is first proposed to convert the state-constrained problem of the leader-following consensus control to the boundedness problem of DNSDF. Then, the distributed control law of each train is designed by combining the command filtering backstepping method and the adaptive neural network approximation technique. Meanwhile, combined with the DNSDF, a novel auxiliary dynamical system (ADS) is designed to compensate for the adverse effects of actuator input saturation, and thus ensure the closed-loop stability of the HSTs system when the state constraints and the input saturation are considered simultaneously. By utilizing the Lyapunov theory, the convergence of the proposed controller is analyzed. Finally, the feasibility and effectiveness of the proposed control scheme are verified by simulations. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This work was motivated by the problem of cooperative control for virtual coupling HSTs with different initial states, actuator input saturation, full-state constraints, etc. The proposed approach addresses the train position and speed constraints by applying DNSDF, which can ensure train coordinated operation with relative braking distance and further reduce the tracking interval between trains. Specifically, the upper bound of the train position constraint varies with the real-time position of the preceding train and the relative speed of the adjacent trains, rather than a constant value. More importantly, an ADS is designed based on the DNSDF, which guarantees the stability of the controller when the input saturation and state constraints exist simultaneously, and avoids the chattering phenomenon of the train control input. The simulation results show that the trains can operate cooperatively at any initial speed within the speed limitations. In future, we will focus on the cooperative control of HSTs with communication delay, and the energy saving optimization cooperative control of HSTs.

Event-Triggered Leader-Following Consensus Control of Nonlinear Multiagent Systems With Generally Uncertain Markovian Switching Topologies

Event-Triggered Leader-Following Consensus Control of Nonlinear Multiagent Systems With Generally Uncertain Markovian Switching Topologies

Dynamic event-triggered consensus control for nonlinear multi-agent systems under DoS attacks.

In this paper, we investigated leader-following consensus control for nonlinear multi-agent systems (MASs) experiencing denial-of-service (DoS) attacks. We proposed a distributed control strategy incorporating an adaptive scheme and a state feedback control gain to eliminate the effects of system nonlinear dynamics and uncertainties. In addition, we introduced a dynamic event-triggered control (DETC) to minimize the utilization of communication resources. Finally, we provided simulation results to show the validity of the proposed approach.

Predefined-Time Consensus Tracking Control for Multiagent System With Channel Fading.

This article proposes a predefined-time leader-following consensus control scheme for a second-order multiagent system (MAS) whose communication network is subject to channel fading. New distributed observers are designed to achieve prescribed-time leader's states estimation under undirected graph and digraph over faded communication channel. Then, a new adaptive dynamic surface predefined-time control is developed for the elimination of the mismatched disturbances stemmed from estimation error and achieving practical predefined-time leader-following consensus. It is proved that the developed control approach achieves predefined-time consensus tracking. This article's contribution is to propose novel distributed observers to remove the influence of channel fading and estimate leader's states under undirected graph and digraph within prescribed time and develop a novel predefined-time control to achieve predefined-time consensus tracking over fading channel. A simulation example verifies that the designed control scheme is effective.

A Delay Classification-Based Approach to Distributed Consensus of Nonlinear Time-Delay Multiagent Systems

This paper investigates the problem of the fixed directed topology-based leader-following consensus control for nonlinear multiagent systems with output delays. Diverging from existing results, this study focuses on large time-varying output delay. Taking this condition into account, a novel delay classification-based distributed output feedback consensus algorithm is developed. First, we divide the output delay into two types through a designed constant and introduce a switching signal to distinguish these two types. Then, we build a distributed compensator for each follower using relevant outputs to reconstitute the leader-following tracking errors. This compensator relies on the output delay and is irrelevant to the nonlinear dynamics of the system. Then, we design a distributed linear controller for each follower with the compensator's assistance. Subsequently, a new unified Lyapunov-Krasovskii functional is developed to prove that all agents can realize leader-following full-state consensus with the action of the controller. We also provide sufficient conditions to demonstrate the controller's validity. Finally, a simulation example is supplied to validate the efficiency of our algorithm.

Leader-following cluster-delay consensus control for first-order nonlinear multi-agent systems based on event-triggered mechanism

In this paper, the event-triggered-based cluster-delay consensus control problem is investigated for leader-following nonlinear multi-agent systems (MASs). In control design, both state triggering in the agents’ network and constant time-delay in the leaders’ communication network are considered. Under the framework of Lyapunov function stability theory, the Lipschitz condition is used to overcome the influence caused by time-delay. In order to further effectively utilize data transmission resources, and reduce the communication load of the topology network between each agent, an event-triggered mechanism is established. Subsequently, a robust cluster consensus control strategy is proposed based on event-triggered mechanism, which can ensure all signals of the controlled system are bounded, and the tracking errors converge to zero. In addition, it can also effectively avoid the Zeno behavior. Finally, the effectiveness of the presented control method and theory is verified by a simulation example.

Two-Phase Performance Adjustment Approach for Distributed Neuroadaptive Consensus Control of Strict-Feedback Multiagent Systems.

This article addresses the practical prescribed-time leaderless consensus problem for multiple networked strict-feedback systems under directed topology. Different from most existing protocols for finite-time consensus that rely on the signum function or fractional power state feedback (thus, the finite convergence time is contingent upon the initial positions of the agents or other design parameters), the proposed distributed neuroadaptive consensus solution is based on a two-phase performance adjustment approach, which exhibits several salient features: 1) the consensus error is ensured to converge to a preassigned arbitrarily small residual set within prescribed time; 2) the tunable transient behavior and desired steady-state control performance of the consensus error is maintained under any unknown initial conditions; and 3) the control scheme involves only one parameter estimation, significantly reducing the design complexity and online computation. Furthermore, we extend the result to practical prescribed-time leader-following consensus control under directed communication topology. Numerical simulation verifies the benefits and efficiency of the proposed method.

Event-Triggered Distributed Consensus Tracking for Nonlinear Multi-Agent Systems: A Minimal Approximation Approach

In this paper, a minimal-approximation-based event-triggered leader-following consensus control scheme is proposed for nonlinear multi-agent systems with unknown actuator dead-zone. To save communication resources, a distributed consensus controller based on the event-sampled states is designed for each follower, which reduces the number of transmissions in the sensor-to-controller and controller-to-actuator channels. Considering that a large number of function approximators are employed in the existing distributed event-triggered schemes of uncertain nonlinear multi-agent systems, thereby consuming massive computational resources. The minimal approximation technology, i.e., designing un-requirement-calculated virtual control laws and employing one function approximator in each local controller, is introduced in our proposed scheme. Meanwhile, the proposed minimal-approximation-based event-triggering mechanism only needs to monitor one triggering condition for each follower, which further reduces the computational burden. Finally, the stability of the closed-loop system is strictly proven by using the Lyapunov extension theorem, and two examples are given to demonstrate the effectiveness of the proposed algorithm.

Discrete-time AUV formation control with leader-following consensus under time-varying delays

In order to enhance the development of marine resources, this study investigates the problem of discrete-time multi-autonomous underwater vehicles (AUV) formation coordination control with leader-following consensus under time-varying delays. First, a discrete-time second-order integration model for AUVs is presented. Second, considering the existence of time-varying delays in AUV communication, the communication between multiple AUVs is classified as valid or invalid based on the maximum delay limit. The problem of AUV formation control under invalid communication is transformed into a formation control problem under switching communication topologies. Then, a time-varying delay communication synchronization strategy is designed to convert asynchronous state information into synchronous state information. Based on synchronous state information, a leader-following consensus control protocol with time-varying delays is proposed, and a controllability analysis is conducted using Lyapunov–Krasovskii functionals. Finally, the stability and effectiveness of the proposed formation-coordination controller and delay synchronization strategy were validated through simulation experiments.

Event-based leader–follower consensus of nonlinear multi-agent systems under denial-of-service

This paper investigates the event-based secure leader-following consensus control for multiple strict feedback nonlinear systems under denial-of-service (DoS) attacks, where only the output signals are available for consensus control design. Observers are designed to estimate the unknown states based on output signals, which are blocked by the attacks. The bounds on the frequency and duration of DoS with respect to the overall time interval are characterized as the parameters for control design and stability analysis. It is shown that the proposed control schemes guarantee that the consensus errors of the multi-agent systems can converge to an adjustable compact set even in presence of DoS attacks. Simulation results are given to illustrate the effectiveness of the proposed algorithms.

Leader-following event-triggered consensus control of MASs under false data injection attacks

Leader-following event-triggered consensus control of MASs under false data injection attacks

Delays-Based Distributed Bipartite Consensus Control of Nonlinear Multiagent Systems With Switching Signed Topologies

This paper explores the distributed leader-following bipartite consensus control issue for nonlinear multiagent systems under switching signed topologies and communication delays. It is permitted that the signed topologies are switched with an average dwell-time condition, and the delays are modeled as the time-varying functions. In the permission, we develop a new dynamic output feedback control-based distributed bipartite consensus method. First, we put forward the delays-dependent distributed switched compensators to the followers, adopting the relevant output information, which are applied to asymptotically estimate the leader-following tracking errors and provide the control signals. Then, we construct the distributed output feedback switched controllers with the linear structure for all followers, which are dependent on the compensators. By utilizing the Lyapunov-Krasovskii functional analysis method, we verify that our proposed controllers can render the agents gaining the bipartite consensus if the switching signal of signed topologies fulfills an average dwell-time condition. Finally, two examples are executed in the simulation to confirm the validity of the given control strategy.

Secure Consensus Control for PDE-Based Multiagent Systems Resist Hybrid Attacks

This article investigates the secure consensus control for a class of multiagent systems (MASs). Considering the spatial dynamic behaviors of each agent, the model based on parabolic partial differential equations (PDE) is developed, which means the evolution of MASs' state with space and time is taken into account. In contrast to traditional consensus studies, this article considers the leader-following consensus control for MASs with Markovian switching topology and spatial distribution characteristic under replay and denial-of-service (DoS) attacks. The system is guaranteed to achieve asymptotical stability by the method of segmented Lyapunov functions with the requirement that all topologies have a directed spanning tree with the leader as the root. Additionally, to save communication resources in PDE-based MASs, an improved dynamic event-triggered mechanism is employed, and it can improve the dynamic performance of the system compared to the traditional ones. Finally, a numerical example and comparative analysis are provided to verify the work in this article.