In this paper, distributed event-triggered performance constraint control is proposed for Heterogeneous Multiagent Systems (HMASs) including quadrotor unmanned aerial vehicles and unmanned ground vehicles in the prese...In this paper, distributed event-triggered performance constraint control is proposed for Heterogeneous Multiagent Systems (HMASs) including quadrotor unmanned aerial vehicles and unmanned ground vehicles in the presence of unknown external disturbances. To tackle the problem of different dynamic characteristics and facilitate the controller design, the virtual variable is introduced in the z axis of the nonlinear model of unmanned ground vehicles. By using this approach, a universal model is established for the HMAS. Moreover, a distributed disturbance observer is established to cope with the adverse influence of the external disturbances. Then, an Appointed-Time Prescribed Performance Function (ATPPF) is designed to restrict the tracking error in the predefined regions. On this basis, the distributed performance constraint controller is proposed for the HMAS based on the ATPPF and the distributed disturbance observer. Furthermore, the improved event-triggered mechanism is proposed with a dynamic threshold, which depends on the distance between the tracking error and the boundary of the ATPPF. Finally, the effectiveness of the proposed control method is verified by the comparative experiments on an HMAS.展开更多
This paper investigates limited-budget consensus design and analysis problems of general high-order multiagent systems with intermittent communications and switching topologies.The main contribution of this paper is t...This paper investigates limited-budget consensus design and analysis problems of general high-order multiagent systems with intermittent communications and switching topologies.The main contribution of this paper is that the tradeoff design between the energy consumption and the consensus performance can be realized while achieving leaderless or leaderfollowing consensus,under constraints of limited budgets and intermittent communications.Firstly,a new intermittent limitedbudget consensus control protocol with a practical trade-off design index is proposed,where the total budget of the whole multiagent system is limited.Then,leaderless limited-budget consensus design and analysis criteria are derived,in which the matrix variables of linear matrix inequalities are determined according to the total budget and the practical trade-off design parameters.Meanwhile,an explicit formulation of the consensus function is derived to describe the consensus state trajectory of the whole system.Moreover,a new two-stage transformation strategy is utilized for leader-following cases,by which the dynamics decomposition of leaderless and leader-following cases can be converted into a unified framework,and sufficient conditions of the leader-following limited-budget consensus design and analysis are determined via those of the leaderless cases.Finally,numerical simulations are given to illustrate theoretical results.展开更多
This paper is concerned with the consensus problem for high-order continuous-time multiagent systems with both state and input delays.A novel approach referred to as pseudopredictor feedback protocol is proposed.Unlik...This paper is concerned with the consensus problem for high-order continuous-time multiagent systems with both state and input delays.A novel approach referred to as pseudopredictor feedback protocol is proposed.Unlike the predictorbased feedback protocol which utilizes the open-loop dynamics to predict the future states,the pseudo-predictor feedback protocol uses the closed-loop dynamics of the multiagent systems to predict the future agent states.Full-order/reduced-order observer-based pseudo-predictor feedback protocols are proposed,and it is shown that the consensus is achieved and the input delay is compensated by the proposed protocols.Necessary and sufficient conditions guaranteeing the stability of the integral delay systems are provided in terms of the stability of the series of retarded-type time-delay systems.Furthermore,compared with the existing predictor-based protocols,the proposed pseudo-predictor feedback protocol is independent of the input signals of the neighboring agents and is easier to implement.Finally,a numerical example is given to demonstrate the effectiveness of the proposed approaches.展开更多
This paper addresses an improved distributed model predictive control （DMPC） scheme for multiagent systems with an attempt to improving its consistency. The deviation between what an agent is actually doing and what...This paper addresses an improved distributed model predictive control （DMPC） scheme for multiagent systems with an attempt to improving its consistency. The deviation between what an agent is actually doing and what its neighbors believe that agent is doing is penalized in the cost function of each agent. At each sampling instant the compatibility constraint of each agent is set tighter than the previous sampling instant. Like the traditional approach, the performance cost is utilized as the Lyapunov function to prove closed-looped stability. The closed-loop stability is guaranteed if the weight matrix for deviation in the cost function are sufficiently large. The proposed distributed control scheme is formulated as quadratic programming with quadratic constraints. A numerical example is given to illustrate the effectiveness of the proposed scheme.展开更多
Personalized search utilizes user preferences to optimize search results,and most existing studies obtain user preferences by analyzing user behaviors in search engines that provide click-through data.However,the beha...Personalized search utilizes user preferences to optimize search results,and most existing studies obtain user preferences by analyzing user behaviors in search engines that provide click-through data.However,the behavioral data are noisy because users often clicked some irrelevant documents to find their required information,and the new user cold start issue represents a serious problem,greatly reducing the performance of personalized search.This paper attempts to utilize online social network data to obtain user preferences that can be used to personalize search results,mine the knowledge of user interests,user influence and user relationships from online social networks,and use this knowledge to optimize the results returned by search engines.The proposed model is based on a holonic multiagent system that improves the adaptability and scalability of the model.The experimental results show that utilizing online social network data to implement personalized search is feasible and that online social network data are significant for personalized search.展开更多
The bipartite consensus problem is addressed for a class of nonlinear time-delay multiagent systems in this paper.Therein,the uncertain nonlinear dynamics of all agents satisfy a Lipschitz growth condition with unknow...The bipartite consensus problem is addressed for a class of nonlinear time-delay multiagent systems in this paper.Therein,the uncertain nonlinear dynamics of all agents satisfy a Lipschitz growth condition with unknown constants,and part of the state information cannot be measured.In this case,a time-varying gain compensator is constructed,which only utilizes the output information of the follower and its neighbors.Subsequently,a distributed output feedback control protocol is proposed on the basis of the compensator.According to Lyapunov stability theory,it is proved that the bipartite consensus can be guaranteed by means of the designed control protocol.Different from the existing literature,this paper studies the leader-follower consensus problem under a weaker connectivity condition,i.e.,the signed directed graph is structurally balanced and contains a directed spanning tree.Two simulation examples are carried out to show the feasibility of the proposed control strategy.展开更多
The objectives of this work are the development and design of disturbance observers (DO’s) for a team of agents that accomplish consensus on agents’ states in the presence of exogenous disturbances. A pinning contro...The objectives of this work are the development and design of disturbance observers (DO’s) for a team of agents that accomplish consensus on agents’ states in the presence of exogenous disturbances. A pinning control strategy is designed for a part of agents of the multiagent systems without disturbances, and this pinning control can bring multiple agents’ states to reaching an expected consensus value. Under the effect of the disturbances, nonlinear disturbance observers are developed for disturbances generated by an exogenous system to estimate the disturbances. Asymptotical consensus of the multiagent systems with disturbances under the composite controller can be achieved. Finally, by applying an example of multiagent systems with switching topologies and exogenous disturbances, the design of the parameters of DO’s are illuminated.展开更多
In this paper,the static consensus problem and the dynamic consensus problem are considered for a class of high-order multiagent systems.With the proposed consensus protocols,necessary and sufficient conditions for th...In this paper,the static consensus problem and the dynamic consensus problem are considered for a class of high-order multiagent systems.With the proposed consensus protocols,necessary and sufficient conditions for the consensus problems are obtained.For the static consensus protocol,the desired consensus speed can be achieved by adjusting feedback gains.Simulations show the effectiveness of the proposed consensus protocols.展开更多
In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is prop...In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is proposed,which consists of a distributed fixed-time observer,a fixed-time disturbance observer,a nonsmooth antidisturbance backstepping controller,and the fixed-time stability analysis is conducted by using the Lyapunov theory correspondingly.This paper includes three main improvements.First,a distributed fixed-time observer is developed for each follower to obtain an estimate of the leader’s output by utilizing the topology of the communication network.Second,a fixed-time disturbance observer is given to estimate the lumped disturbances for feedforward compensation.Finally,a nonsmooth antidisturbance backstepping tracking controller with feedforward compensation for lumped disturbances is designed.In order to mitigate the“explosion of complexity”in the tradi-tional backstepping approach,we have implemented a modified nonsmooth command filter to enhance the performance of the closed-loop system.The simulation results show that the pro-posed method is effective.展开更多
This paper addresses the distributed optimization problem of discrete-time multiagent systems with nonconvex control input constraints and switching topologies.We introduce a novel distributed optimization algorithm w...This paper addresses the distributed optimization problem of discrete-time multiagent systems with nonconvex control input constraints and switching topologies.We introduce a novel distributed optimization algorithm with a switching mechanism to guarantee that all agents eventually converge to an optimal solution point,while their control inputs are constrained in their own nonconvex region.It is worth noting that the mechanism is performed to tackle the coexistence of the nonconvex constraint operator and the optimization gradient term.Based on the dynamic transformation technique,the original nonlinear dynamic system is transformed into an equivalent one with a nonlinear error term.By utilizing the nonnegative matrix theory,it is shown that the optimization problem can be solved when the union of switching communication graphs is jointly strongly connected.Finally,a numerical simulation example is used to demonstrate the acquired theoretical results.展开更多
In this paper,a class of time-varying output group formation containment control problem of general linear hetero-geneous multiagent systems(MASs)is investigated under directed topology.The MAS is composed of a number...In this paper,a class of time-varying output group formation containment control problem of general linear hetero-geneous multiagent systems(MASs)is investigated under directed topology.The MAS is composed of a number of tracking leaders,formation leaders and followers,where two different types of leaders are used to provide reference trajectories for movement and to achieve certain formations,respectively.Firstly,compen-sators are designed whose states are estimations of tracking lead-ers,based on which,a controller is developed for each formation leader to accomplish the expected formation.Secondly,two event-triggered compensators are proposed for each follower to evalu-ate the state and formation information of the formation leaders in the same group,respectively.Subsequently,a control protocol is designed for each follower,utilizing the output information,to guide the output towards the convex hull generated by the forma-tion leaders within the group.Next,the triggering sequence in this paper is decomposed into two sequences,and the inter-event intervals of these two triggering conditions are provided to rule out the Zeno behavior.Finally,a numerical simulation is intro-duced to confirm the validity of the proposed results.展开更多
Redefined benefit-driven function is used to study the dynamic scheduling of FMS based on multiagent architecture. Each agent is dedicated to a work center, i.e. a set of the manufacturing system. In one hand, each ag...Redefined benefit-driven function is used to study the dynamic scheduling of FMS based on multiagent architecture. Each agent is dedicated to a work center, i.e. a set of the manufacturing system. In one hand, each agent selects locally and dynamically the dispatching rule(DR) that seems to be most suited to the operating conditions, production objectives and current shop status. On the other hand, each task should bring certain amount of benefit for the manufacturer. So, it is reasonable to have the dynamic scheduling of FMS relying upon multiagent architecture using the benefit-driven function as a strategy. Well, today's manufacturing corporation, especially the high & new technology one and deep machining one, the cost of their products is mainly determined by how much the knowledge is input From this viewpoint, we redefined the benefit-driven function, hi the end, this approach is compared with other existing DRs on a job-shop problem, already used in other research works.展开更多
Dear Editor,Aiming at the consensus tracking problem of a class of unknown heterogeneous nonlinear multiagent systems(MASs)with input constraints,a novel data-driven iterative learning consensus control(ILCC)protocol ...Dear Editor,Aiming at the consensus tracking problem of a class of unknown heterogeneous nonlinear multiagent systems(MASs)with input constraints,a novel data-driven iterative learning consensus control(ILCC)protocol based on zeroing neural networks(ZNNs)is proposed.First,a dynamic linearization data model(DLDM)is acquired via dynamic linearization technology(DLT).展开更多
In this study,we investigate the self-triggered impulsive control for stochastic delayed multiagent systems with input saturation.We present a novel self-triggered mechanism using a comparison system method.The next t...In this study,we investigate the self-triggered impulsive control for stochastic delayed multiagent systems with input saturation.We present a novel self-triggered mechanism using a comparison system method.The next triggering instant is predicted on the basis of agent dynamics knowledge and data obtained from the last triggering instant without real-time monitoring;thus,Zeno behavior is naturally avoided.By applying this new self-triggering mechanism,we provide some sufficient conditions for the mean-square consensus based on the stochastic differential theory,Lyapunov function theory,and linear matrix inequalities.Finally,we demonstrate the feasibility of our method by presenting numerical simulation results.展开更多
This work investigates the implementation of distributed prescribed-time neural network(NN)control for nonlinear multiagent systems(MASs)using a dynamic memory event-triggered mechanism(DMETM).First,it introduces a co...This work investigates the implementation of distributed prescribed-time neural network(NN)control for nonlinear multiagent systems(MASs)using a dynamic memory event-triggered mechanism(DMETM).First,it introduces a composite learning technique in NN control.This method leverages the prediction error within the NN update law to enhance the accuracy of the unknown nonlinearity estimation.Subsequently,by introducing a time-varying transformation,the study establishes a distributed prescribed-time control algorithm.The notable feature of this algorithm is its ability to predetermine the convergence time independently of initial conditions or control parameters.Moreover,the DMETM is established to reduce the actuation frequency of the controller.Unlike the conventional memoryless dynamic event-triggered mechanism,the DMETM incorporates a memory term to further increase triggering intervals.Utilizing a distributed estimator for the leader,the DMETM-based NN prescribed-time controller is designed in a fully distributed manner,which guarantees that all signals in the closed-loop system remain bounded within the prescribed time.Finally,simulation results are presented to validate the effectiveness of the proposed algorithm.展开更多
In the distributed security control for air-sea heterogeneous multiagent systems(HMASs)with cooperative-antagonistic interactions,data security and transient-steady state performance of the system are two key problems...In the distributed security control for air-sea heterogeneous multiagent systems(HMASs)with cooperative-antagonistic interactions,data security and transient-steady state performance of the system are two key problems.To ensure data security,an intermittent privacy preservation(IPP)mechanism is proposed for the first time.A novel setting time initial mask function and a novel intermittent mask function are constructed.Users can implement intermittent preservation for the system according to actual requirements,which solves the irreversibility problem after conventional mask disappears and balances control accuracy and system security.To ensure transient-steady state performance,a novel error transformation function(ETF)is proposed and integrated into the predefined-time prescribed performance control strategy.Compared to conventional hyperbolic tangent type ETFs,the proposed ETF can improve the convergence accuracy of errors under the same conditions.Furthermore,a unified model of the air-sea HMASs is established,which improves the model accuracy compared with the simplified model.Finally,the proposed IPP security control strategy is applied to the air-sea delivery mission to verify its feasibility and effectiveness.展开更多
In this paper, consensus problems in discrete-time multiagent systems with time-invariant delays are considered. In order to characterize the structures of communication topologies, the concept of ＂pre-leader-followe...In this paper, consensus problems in discrete-time multiagent systems with time-invariant delays are considered. In order to characterize the structures of communication topologies, the concept of ＂pre-leader-follower＂ decomposition is introduced. Then, a necessary and sufficient condition for state consensus is established. By this method, consensus problems in networks with a single time-delay, as well as with multiple time-delays, are studied, and some necessary and sufficient conditions for solvability of consensus problems are obtained.展开更多
A novel adaptive output feedback control approach is presented for formation tracking of a multiagent system with uncertainties and quantized input signals. The agents are described by nonlinear dynamics models with u...A novel adaptive output feedback control approach is presented for formation tracking of a multiagent system with uncertainties and quantized input signals. The agents are described by nonlinear dynamics models with unknown parameters and immeasurable states. A high-gain dynamic state observer is established to estimate the immeasurable states. With a proper design parameter choice, an adaptive output feedback control method is developed employing a hysteretic quantizer and the designed dynamic state observer. Stability analysis shows that the control strategy can guarantee that the agents can maintain the formation shape while tracking the reference trajectory. In addition, all the signals in the closed-loop system are bounded. The effectiveness of the control strategy is validated by simulation.展开更多
Abstract In this thesis, multiagent system specifications, multiagent system architectures, agent communication languages and agent communication protocols, automatic abstracting based on multiagent technologies are ...Abstract In this thesis, multiagent system specifications, multiagent system architectures, agent communication languages and agent communication protocols, automatic abstracting based on multiagent technologies are studied. Some concerned problems of designs and realization of automatic abstracting systems based on multiagent technologies are studied, too. Chapter 1 shows the significance and objectives of the thesis, its main contents are summarized, and innovations of the thesis are showed. Some basic concepts of agents and multiagent systems are studied in Chapter 2. The definitions of agents and multiagent systems are given, and the theory, technologies and applications of multiagent systems are summarized. Furthermore, some important studying trends of multiagent systems are set forward. Multiagent system specifications are studied in Chapter 3. MAS/KIB—a multiagent system specification is built using mental states such as K (Know), B (Belief), and I (Intention), its grammar and semanteme are discussed, axioms and inference rules are given, and some properties are researched. We also compare MAS/KIB with other existing specifications. MAS/KIB has the following characteristics: (1) each agent has its own world outlook; (2) no global data in the system; (3) processes of state changes are used as indexes to systems; (4) it has the characteristics of not only time series logic but also dynamic logic; and (5) interactive actions are included. The architectures of multiagent systems are studied in Chapter 4. First, we review some typical architecture of multiagent systems, agent network architecture, agent federated architecture, agent blackboard architecture, and Foundation of Intelligent Physical Agent(FIPA) architecture. For the first time, we set forward and study the layering and partitioning models of the architectures of multiagent systems, organizing architecture models, and interoperability architecture model of multiagent systems. Chapter 5 studies agent communication languages. We study FIPA Agent Communication Language(ACL) message grammar, Communicative Act(CA) types, ACL semantics and Agent Communication Protocols. The string grammar of ACL messages and SL grammar represented by EBNF are given, and a new ACL semantic model is set forward. We study automatic abstracting based on multiagent technologies in Chapter 6. For the first time, the idea of constructing automatic abstracting systems based on multiagent technologies is set forward, and the necessity and feasibility of constructing such systems are set forth. The architecture of automatic abstracting systems based on multiagent technologies is provided, and the basic elements and mutual relations are studied. We set forth the working principle of the automatic abstracting systems based on multiagent technologies and how the contradiction of domain currency and abstract quality of automatic abstracting systems is resolved. Studies, simulation analysis and design of the automatic abstracting experimental system based on multiagent technologies(ABES/MAT) are made in Chapter 7. We study the architecture of ABES/MAT, and set forth its basic elements and mutual relations. The user model and mathematics descriptions of ABES/MAT in the Internet environment are provided. Three coordination algorithms that synthetically use environment information, system information and history information are set forward. Then, we analyze the performance of ABES/MAT based on the simulations, and get suitable number fo abstracting agents for each domain in a given load. Finally, we compare the three coordination algorithms. The realization of ABES/MAT is introduced in Chapter 8. Firstly, we study the problem of the agentification of legacy systems, and show how to realize the agentification of glanc, ladies and news. Then, the architectures and functions of Coordination Management Agent(CMA) and Information Agent(IA) are set forth. The agent naming grammar represented by EBNF is given., In the following, we explain the designed agent communicative acts and management展开更多
There are mainly two different ways of learning for animals and humans:trying on yourself through interactions or imitating/copying others through communication/observation.How these two learning strategies differ and...There are mainly two different ways of learning for animals and humans:trying on yourself through interactions or imitating/copying others through communication/observation.How these two learning strategies differ and what roles they are playing in achieving coordination among individuals are two challenging problems for researchers from various disciplines.In multiagent systems,most existing work simply focuses on individual learning for achieving coordination among agents.The social learning perspective has been largely neglected.Against this background,this article contributes by proposing an integrated solution to decision making between social learning and individual learning in multiagent systems.Two integration modes have been proposed that enable agents to choose in between these two learning strategies,either in a t'Lxed or in an adaptive manner.Experimental evaluations have shown that these two kinds of leaning strategies have different roles in maintaining efficient coordination among agents.These differences can reveal some significant insights into the manipulation and control of agent behaviors in multiagent systems,and also shed light on understanding the social factors in shaping coordinated behaviors in humans and animals.展开更多
基金supported in part by the National Natural Science Foundation of China(Nos.U23B2036,U2013201).
文摘In this paper, distributed event-triggered performance constraint control is proposed for Heterogeneous Multiagent Systems (HMASs) including quadrotor unmanned aerial vehicles and unmanned ground vehicles in the presence of unknown external disturbances. To tackle the problem of different dynamic characteristics and facilitate the controller design, the virtual variable is introduced in the z axis of the nonlinear model of unmanned ground vehicles. By using this approach, a universal model is established for the HMAS. Moreover, a distributed disturbance observer is established to cope with the adverse influence of the external disturbances. Then, an Appointed-Time Prescribed Performance Function (ATPPF) is designed to restrict the tracking error in the predefined regions. On this basis, the distributed performance constraint controller is proposed for the HMAS based on the ATPPF and the distributed disturbance observer. Furthermore, the improved event-triggered mechanism is proposed with a dynamic threshold, which depends on the distance between the tracking error and the boundary of the ATPPF. Finally, the effectiveness of the proposed control method is verified by the comparative experiments on an HMAS.
基金supported by the National Natural Science Foundation of China(62003363,61703411)China Postdoctoral Science Foundation(271004)+1 种基金Science Foundation for Distinguished Youth of Shaanxi Province(2021JC-35)Youth Science Foundation of Shaanxi Province(2021JQ-375)。
文摘This paper investigates limited-budget consensus design and analysis problems of general high-order multiagent systems with intermittent communications and switching topologies.The main contribution of this paper is that the tradeoff design between the energy consumption and the consensus performance can be realized while achieving leaderless or leaderfollowing consensus,under constraints of limited budgets and intermittent communications.Firstly,a new intermittent limitedbudget consensus control protocol with a practical trade-off design index is proposed,where the total budget of the whole multiagent system is limited.Then,leaderless limited-budget consensus design and analysis criteria are derived,in which the matrix variables of linear matrix inequalities are determined according to the total budget and the practical trade-off design parameters.Meanwhile,an explicit formulation of the consensus function is derived to describe the consensus state trajectory of the whole system.Moreover,a new two-stage transformation strategy is utilized for leader-following cases,by which the dynamics decomposition of leaderless and leader-following cases can be converted into a unified framework,and sufficient conditions of the leader-following limited-budget consensus design and analysis are determined via those of the leaderless cases.Finally,numerical simulations are given to illustrate theoretical results.
基金supported in part by the National Natural Science Foundation of China(61903282,61625305)China Postdoctoral Science Foundation(2020T130488)9。
文摘This paper is concerned with the consensus problem for high-order continuous-time multiagent systems with both state and input delays.A novel approach referred to as pseudopredictor feedback protocol is proposed.Unlike the predictorbased feedback protocol which utilizes the open-loop dynamics to predict the future states,the pseudo-predictor feedback protocol uses the closed-loop dynamics of the multiagent systems to predict the future agent states.Full-order/reduced-order observer-based pseudo-predictor feedback protocols are proposed,and it is shown that the consensus is achieved and the input delay is compensated by the proposed protocols.Necessary and sufficient conditions guaranteeing the stability of the integral delay systems are provided in terms of the stability of the series of retarded-type time-delay systems.Furthermore,compared with the existing predictor-based protocols,the proposed pseudo-predictor feedback protocol is independent of the input signals of the neighboring agents and is easier to implement.Finally,a numerical example is given to demonstrate the effectiveness of the proposed approaches.
基金supported by the National Natural Science Foundation of China(No.60874046,60974090)the Ph.D.Programs Foundation of the Ministry of Education of China(No.200806110021)the Natural Science Foundation of Chongqing of China(CSTS No.2008BB2049)
文摘This paper addresses an improved distributed model predictive control （DMPC） scheme for multiagent systems with an attempt to improving its consistency. The deviation between what an agent is actually doing and what its neighbors believe that agent is doing is penalized in the cost function of each agent. At each sampling instant the compatibility constraint of each agent is set tighter than the previous sampling instant. Like the traditional approach, the performance cost is utilized as the Lyapunov function to prove closed-looped stability. The closed-loop stability is guaranteed if the weight matrix for deviation in the cost function are sufficiently large. The proposed distributed control scheme is formulated as quadratic programming with quadratic constraints. A numerical example is given to illustrate the effectiveness of the proposed scheme.
基金supported by the National Natural Science Foundation of China (61972300, 61672401, 61373045, and 61902288,)the Pre-Research Project of the “Thirteenth Five-Year-Plan” of China (315***10101 and 315**0102)
文摘Personalized search utilizes user preferences to optimize search results,and most existing studies obtain user preferences by analyzing user behaviors in search engines that provide click-through data.However,the behavioral data are noisy because users often clicked some irrelevant documents to find their required information,and the new user cold start issue represents a serious problem,greatly reducing the performance of personalized search.This paper attempts to utilize online social network data to obtain user preferences that can be used to personalize search results,mine the knowledge of user interests,user influence and user relationships from online social networks,and use this knowledge to optimize the results returned by search engines.The proposed model is based on a holonic multiagent system that improves the adaptability and scalability of the model.The experimental results show that utilizing online social network data to implement personalized search is feasible and that online social network data are significant for personalized search.
基金supported by the National Natural ScienceFoundation ofChina(Nos.61973189,62073190)the Research Fund for the Taishan Scholar Project of Shandong Province of China(No.ts20190905)the Natural Science Foundation of Shandong Province of China(No.ZR2020ZD25).
文摘The bipartite consensus problem is addressed for a class of nonlinear time-delay multiagent systems in this paper.Therein,the uncertain nonlinear dynamics of all agents satisfy a Lipschitz growth condition with unknown constants,and part of the state information cannot be measured.In this case,a time-varying gain compensator is constructed,which only utilizes the output information of the follower and its neighbors.Subsequently,a distributed output feedback control protocol is proposed on the basis of the compensator.According to Lyapunov stability theory,it is proved that the bipartite consensus can be guaranteed by means of the designed control protocol.Different from the existing literature,this paper studies the leader-follower consensus problem under a weaker connectivity condition,i.e.,the signed directed graph is structurally balanced and contains a directed spanning tree.Two simulation examples are carried out to show the feasibility of the proposed control strategy.
基金supported by the National Natural Science Foundation of China (No.60875039, 60774016, 60904022, 60805039)
文摘The objectives of this work are the development and design of disturbance observers (DO’s) for a team of agents that accomplish consensus on agents’ states in the presence of exogenous disturbances. A pinning control strategy is designed for a part of agents of the multiagent systems without disturbances, and this pinning control can bring multiple agents’ states to reaching an expected consensus value. Under the effect of the disturbances, nonlinear disturbance observers are developed for disturbances generated by an exogenous system to estimate the disturbances. Asymptotical consensus of the multiagent systems with disturbances under the composite controller can be achieved. Finally, by applying an example of multiagent systems with switching topologies and exogenous disturbances, the design of the parameters of DO’s are illuminated.
基金supported by the National Natural Science Foundation of China(No.10701042)
文摘In this paper,the static consensus problem and the dynamic consensus problem are considered for a class of high-order multiagent systems.With the proposed consensus protocols,necessary and sufficient conditions for the consensus problems are obtained.For the static consensus protocol,the desired consensus speed can be achieved by adjusting feedback gains.Simulations show the effectiveness of the proposed consensus protocols.
基金supported by the National Defense Basic Scientific Research Project(JCKY2020130C025)the National Science and Technology Major Project(J2019-III-0020-0064,J2019-V-0014-0109)。
文摘In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is proposed,which consists of a distributed fixed-time observer,a fixed-time disturbance observer,a nonsmooth antidisturbance backstepping controller,and the fixed-time stability analysis is conducted by using the Lyapunov theory correspondingly.This paper includes three main improvements.First,a distributed fixed-time observer is developed for each follower to obtain an estimate of the leader’s output by utilizing the topology of the communication network.Second,a fixed-time disturbance observer is given to estimate the lumped disturbances for feedforward compensation.Finally,a nonsmooth antidisturbance backstepping tracking controller with feedforward compensation for lumped disturbances is designed.In order to mitigate the“explosion of complexity”in the tradi-tional backstepping approach,we have implemented a modified nonsmooth command filter to enhance the performance of the closed-loop system.The simulation results show that the pro-posed method is effective.
基金Project supported by the National Engineering Research Center of Rail Transportation Operation and Control System,Beijing Jiaotong University(Grant No.NERC2019K002)。
文摘This paper addresses the distributed optimization problem of discrete-time multiagent systems with nonconvex control input constraints and switching topologies.We introduce a novel distributed optimization algorithm with a switching mechanism to guarantee that all agents eventually converge to an optimal solution point,while their control inputs are constrained in their own nonconvex region.It is worth noting that the mechanism is performed to tackle the coexistence of the nonconvex constraint operator and the optimization gradient term.Based on the dynamic transformation technique,the original nonlinear dynamic system is transformed into an equivalent one with a nonlinear error term.By utilizing the nonnegative matrix theory,it is shown that the optimization problem can be solved when the union of switching communication graphs is jointly strongly connected.Finally,a numerical simulation example is used to demonstrate the acquired theoretical results.
基金supported in part by the National Key Research and Development Program of China(2018YFA0702200)the National Natural Science Foundation of China(52377079,62203097,62373196)。
文摘In this paper,a class of time-varying output group formation containment control problem of general linear hetero-geneous multiagent systems(MASs)is investigated under directed topology.The MAS is composed of a number of tracking leaders,formation leaders and followers,where two different types of leaders are used to provide reference trajectories for movement and to achieve certain formations,respectively.Firstly,compen-sators are designed whose states are estimations of tracking lead-ers,based on which,a controller is developed for each formation leader to accomplish the expected formation.Secondly,two event-triggered compensators are proposed for each follower to evalu-ate the state and formation information of the formation leaders in the same group,respectively.Subsequently,a control protocol is designed for each follower,utilizing the output information,to guide the output towards the convex hull generated by the forma-tion leaders within the group.Next,the triggering sequence in this paper is decomposed into two sequences,and the inter-event intervals of these two triggering conditions are provided to rule out the Zeno behavior.Finally,a numerical simulation is intro-duced to confirm the validity of the proposed results.
基金the important project of NSFC (Grant No.59990470)
文摘Redefined benefit-driven function is used to study the dynamic scheduling of FMS based on multiagent architecture. Each agent is dedicated to a work center, i.e. a set of the manufacturing system. In one hand, each agent selects locally and dynamically the dispatching rule(DR) that seems to be most suited to the operating conditions, production objectives and current shop status. On the other hand, each task should bring certain amount of benefit for the manufacturer. So, it is reasonable to have the dynamic scheduling of FMS relying upon multiagent architecture using the benefit-driven function as a strategy. Well, today's manufacturing corporation, especially the high & new technology one and deep machining one, the cost of their products is mainly determined by how much the knowledge is input From this viewpoint, we redefined the benefit-driven function, hi the end, this approach is compared with other existing DRs on a job-shop problem, already used in other research works.
基金supported by the National Nature Science Foundation of China(U21A20166)the Science and Technology Development Foundation of Jilin Province(20230508095RC)+2 种基金the Major Science and Technology Projects of Jilin Province and Changchun City(20220301033GX)the Development and Reform Commission Foundation of Jilin Province(2023C034-3)the Interdisciplinary Integration and Innovation Project of JLU(JLUXKJC2020202).
文摘Dear Editor,Aiming at the consensus tracking problem of a class of unknown heterogeneous nonlinear multiagent systems(MASs)with input constraints,a novel data-driven iterative learning consensus control(ILCC)protocol based on zeroing neural networks(ZNNs)is proposed.First,a dynamic linearization data model(DLDM)is acquired via dynamic linearization technology(DLT).
基金supported by the National Natural Science Foundation of China(Grant Nos.62433018,62033003,62276214)。
文摘In this study,we investigate the self-triggered impulsive control for stochastic delayed multiagent systems with input saturation.We present a novel self-triggered mechanism using a comparison system method.The next triggering instant is predicted on the basis of agent dynamics knowledge and data obtained from the last triggering instant without real-time monitoring;thus,Zeno behavior is naturally avoided.By applying this new self-triggering mechanism,we provide some sufficient conditions for the mean-square consensus based on the stochastic differential theory,Lyapunov function theory,and linear matrix inequalities.Finally,we demonstrate the feasibility of our method by presenting numerical simulation results.
基金partially supported by the National Natural Science Foundation of China(Grant Nos.62033003,62373113,62203119)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515011527,2023B1515120010)。
文摘This work investigates the implementation of distributed prescribed-time neural network(NN)control for nonlinear multiagent systems(MASs)using a dynamic memory event-triggered mechanism(DMETM).First,it introduces a composite learning technique in NN control.This method leverages the prediction error within the NN update law to enhance the accuracy of the unknown nonlinearity estimation.Subsequently,by introducing a time-varying transformation,the study establishes a distributed prescribed-time control algorithm.The notable feature of this algorithm is its ability to predetermine the convergence time independently of initial conditions or control parameters.Moreover,the DMETM is established to reduce the actuation frequency of the controller.Unlike the conventional memoryless dynamic event-triggered mechanism,the DMETM incorporates a memory term to further increase triggering intervals.Utilizing a distributed estimator for the leader,the DMETM-based NN prescribed-time controller is designed in a fully distributed manner,which guarantees that all signals in the closed-loop system remain bounded within the prescribed time.Finally,simulation results are presented to validate the effectiveness of the proposed algorithm.
基金partially supported by the National Natural Science Foundation of China(Grant No.62322307)the Sichuan Science and Technology Program(Grant No.2023NSFSC1968)+1 种基金the Basic Research Project of the Educational Department of Liaoning Province(Grant No.LJ232410167028)the Revitalization of Liaoning Talents Program(Grant No.XLYC2203201)。
文摘In the distributed security control for air-sea heterogeneous multiagent systems(HMASs)with cooperative-antagonistic interactions,data security and transient-steady state performance of the system are two key problems.To ensure data security,an intermittent privacy preservation(IPP)mechanism is proposed for the first time.A novel setting time initial mask function and a novel intermittent mask function are constructed.Users can implement intermittent preservation for the system according to actual requirements,which solves the irreversibility problem after conventional mask disappears and balances control accuracy and system security.To ensure transient-steady state performance,a novel error transformation function(ETF)is proposed and integrated into the predefined-time prescribed performance control strategy.Compared to conventional hyperbolic tangent type ETFs,the proposed ETF can improve the convergence accuracy of errors under the same conditions.Furthermore,a unified model of the air-sea HMASs is established,which improves the model accuracy compared with the simplified model.Finally,the proposed IPP security control strategy is applied to the air-sea delivery mission to verify its feasibility and effectiveness.
基金the National Natural Science Foundation of China (Grant Nos. 60674050 and 60528007)the National 973 Program (Grant No.2002CB312200)+1 种基金the National 863 Program (Grant No. 2006AA04Z258)11-5 project (Grant No. A2120061303)
文摘In this paper, consensus problems in discrete-time multiagent systems with time-invariant delays are considered. In order to characterize the structures of communication topologies, the concept of ＂pre-leader-follower＂ decomposition is introduced. Then, a necessary and sufficient condition for state consensus is established. By this method, consensus problems in networks with a single time-delay, as well as with multiple time-delays, are studied, and some necessary and sufficient conditions for solvability of consensus problems are obtained.
基金supported by the National Natural Science Foundation of China(No.20155896025)
文摘A novel adaptive output feedback control approach is presented for formation tracking of a multiagent system with uncertainties and quantized input signals. The agents are described by nonlinear dynamics models with unknown parameters and immeasurable states. A high-gain dynamic state observer is established to estimate the immeasurable states. With a proper design parameter choice, an adaptive output feedback control method is developed employing a hysteretic quantizer and the designed dynamic state observer. Stability analysis shows that the control strategy can guarantee that the agents can maintain the formation shape while tracking the reference trajectory. In addition, all the signals in the closed-loop system are bounded. The effectiveness of the control strategy is validated by simulation.
文摘Abstract In this thesis, multiagent system specifications, multiagent system architectures, agent communication languages and agent communication protocols, automatic abstracting based on multiagent technologies are studied. Some concerned problems of designs and realization of automatic abstracting systems based on multiagent technologies are studied, too. Chapter 1 shows the significance and objectives of the thesis, its main contents are summarized, and innovations of the thesis are showed. Some basic concepts of agents and multiagent systems are studied in Chapter 2. The definitions of agents and multiagent systems are given, and the theory, technologies and applications of multiagent systems are summarized. Furthermore, some important studying trends of multiagent systems are set forward. Multiagent system specifications are studied in Chapter 3. MAS/KIB—a multiagent system specification is built using mental states such as K (Know), B (Belief), and I (Intention), its grammar and semanteme are discussed, axioms and inference rules are given, and some properties are researched. We also compare MAS/KIB with other existing specifications. MAS/KIB has the following characteristics: (1) each agent has its own world outlook; (2) no global data in the system; (3) processes of state changes are used as indexes to systems; (4) it has the characteristics of not only time series logic but also dynamic logic; and (5) interactive actions are included. The architectures of multiagent systems are studied in Chapter 4. First, we review some typical architecture of multiagent systems, agent network architecture, agent federated architecture, agent blackboard architecture, and Foundation of Intelligent Physical Agent(FIPA) architecture. For the first time, we set forward and study the layering and partitioning models of the architectures of multiagent systems, organizing architecture models, and interoperability architecture model of multiagent systems. Chapter 5 studies agent communication languages. We study FIPA Agent Communication Language(ACL) message grammar, Communicative Act(CA) types, ACL semantics and Agent Communication Protocols. The string grammar of ACL messages and SL grammar represented by EBNF are given, and a new ACL semantic model is set forward. We study automatic abstracting based on multiagent technologies in Chapter 6. For the first time, the idea of constructing automatic abstracting systems based on multiagent technologies is set forward, and the necessity and feasibility of constructing such systems are set forth. The architecture of automatic abstracting systems based on multiagent technologies is provided, and the basic elements and mutual relations are studied. We set forth the working principle of the automatic abstracting systems based on multiagent technologies and how the contradiction of domain currency and abstract quality of automatic abstracting systems is resolved. Studies, simulation analysis and design of the automatic abstracting experimental system based on multiagent technologies(ABES/MAT) are made in Chapter 7. We study the architecture of ABES/MAT, and set forth its basic elements and mutual relations. The user model and mathematics descriptions of ABES/MAT in the Internet environment are provided. Three coordination algorithms that synthetically use environment information, system information and history information are set forward. Then, we analyze the performance of ABES/MAT based on the simulations, and get suitable number fo abstracting agents for each domain in a given load. Finally, we compare the three coordination algorithms. The realization of ABES/MAT is introduced in Chapter 8. Firstly, we study the problem of the agentification of legacy systems, and show how to realize the agentification of glanc, ladies and news. Then, the architectures and functions of Coordination Management Agent(CMA) and Information Agent(IA) are set forth. The agent naming grammar represented by EBNF is given., In the following, we explain the designed agent communicative acts and management
文摘There are mainly two different ways of learning for animals and humans:trying on yourself through interactions or imitating/copying others through communication/observation.How these two learning strategies differ and what roles they are playing in achieving coordination among individuals are two challenging problems for researchers from various disciplines.In multiagent systems,most existing work simply focuses on individual learning for achieving coordination among agents.The social learning perspective has been largely neglected.Against this background,this article contributes by proposing an integrated solution to decision making between social learning and individual learning in multiagent systems.Two integration modes have been proposed that enable agents to choose in between these two learning strategies,either in a t'Lxed or in an adaptive manner.Experimental evaluations have shown that these two kinds of leaning strategies have different roles in maintaining efficient coordination among agents.These differences can reveal some significant insights into the manipulation and control of agent behaviors in multiagent systems,and also shed light on understanding the social factors in shaping coordinated behaviors in humans and animals.
