Adaptive Event-Triggered Time-Varying Output Group Formation Containment Control of Heterogeneous Multiagent Systems

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.

Distributed Adaptive Output Consensus of Unknown Heterogeneous Non-Minimum Phase Multi-Agent Systems

This article addresses the leader-following output consensus problem of heterogeneous linear multi-agent systems with unknown agent parameters under directed graphs.The dynamics of followers are allowed to be non-minimum phase with unknown arbitrary individual relative degrees.This is contrary to many existing works on distributed adaptive control schemes where agent dynamics are required to be minimum phase and often of the same relative degree.A distributed adaptive pole placement control scheme is developed,which consists of a distributed observer and an adaptive pole placement control law.It is shown that under the proposed distributed adaptive control scheme,all signals in the closed-loop system are bounded and the outputs of all the followers track the output of the leader asymptotically.The effectiveness of the proposed scheme is demonstrated by one practical example and one numerical example.

Lyapunov-Based Output Containment Control of Heterogeneous Multi-Agent Systems With Markovian Switching Topologies and Distributed Delays

This paper considers the mean square output containment control problem for heterogeneous multi-agent systems(MASs)with randomly switching topologies and nonuniform distributed delays.By modeling the switching topologies as a continuous-time Markov process and taking the distributed delays into consideration,a novel distributed containment observer is proposed to estimate the convex hull spanned by the leaders'states.A novel distributed output feedback containment controller is then designed without using the prior knowledge of distributed delays.By constructing a novel switching Lyapunov functional,the output containment control problem is then solved in the sense of mean square under an easily-verifiable sufficient condition.Finally,two numerical examples are given to show the effectiveness of the proposed controller.

Consensus pursuit of heterogeneous multi-agent systems under a directed acyclic graph

This paper is concerned with the cooperative target pursuit problem by multiple agents based on directed acyclic graph. The target appears at a random location and moves only when sensed by the agents, and agents will pursue the target once they detect its existence. Since the ability of each agent may be different, we consider the heterogeneous multi-agent systems. According to the topology of the multi-agent systems, a novel consensus-based control law is proposed, where the target and agents are modeled as a leader and followers, respectively. Based on Mason＇s rule and signal flow graph analysis, the convergence conditions are provided to show that the agents can catch the target in a finite time. Finally, simulation studies are provided to verify the effectiveness of the proposed approach.

Consensus of heterogeneous multi-agent systems based on sampled data with a small sampling delay

In this paper, consensus problems of heterogeneous multi-agent systems based on sampled data with a small sampling delay are considered. First, a consensus protocol based on sampled data with a small sampling delay for heterogeneous multi-agent systems is proposed. Then, the algebra graph theory, the matrix method, the stability theory of linear systems, and some other techniques are employed to derive the necessary and sufficient conditions guaranteeing heterogeneous multi-agent systems to asymptotically achieve the stationary consensus. Finally, simulations are performed to demonstrate the correctness of the theoretical results.

Controllability of heterogeneous interdependent group systems under undirected and directed topology

The controllability problem of heterogeneous interdependent group systems with undirected and directed topology is investigated in this paper. First, the interdependent model of the heterogeneous system is set up according to the difference of individual characteristics. An extended distributed protocol with the external sliding-mode control is designed, under which it is shown that a heterogeneous interdependent group system is controllable when the corresponding communication topology is controllable. Then, using the network eigenvalue method, the driving individuals are determined for a heterogeneous system with undirected topology. Under directed topology, the maximum match method is utilized to confirm the driving individuals. Some sufficient and necessary conditions are presented to assure that the heterogeneous interdependent group system is structurally controllable. Via theoretical analysis, the controllability of heterogeneous interdependent systems is related to the interdependent manner and the structure of the heterogeneous system. Numerical simulations are provided to demonstrate the effectiveness of the theoretical results.

Partitioned k-Exclusion Real-Time Locking Protocol Motivated by Multicore Multi-GPU Systems

Graphic processing units （GPUs） have been widely recognized as cost-efficient co-processors with acceptable size, weight, and power consumption. However, adopting GPUs in real-time systems is still challenging, due to the lack in framework for real-time analysis. In order to guarantee real-time requirements while maintaining system utilization ~in modern heterogeneous systems, such as multicore multi-GPU systems, a novel suspension-based k-exclusion real-time locking protocol and the associated suspension-aware schedulability analysis are proposed. The proposed protocol provides a synchronization framework that enables multiple GPUs to be efficiently integrated in multicore real-time systems. Comparative evaluations show that the proposed methods improve upon the existing work in terms of schedulability.

Mean-Square Output Consensus of Heterogeneous Multi-Agent Systems with Multiplicative Noises in Dynamics and Measurements

This paper studies the output consensus problem of heterogeneous linear stochastic multiagent systems with multiplicative noises in system parameters and measurements,where the system noise in each agent is allowed to be different.By employing stochastic output regulation theory and the stochastic Lyapunov function approach,a composite controller embedded with stochastic output regulator equations(SOREs)and a stochastic dynamic compensator is designed to achieve the meansquare output consensus of the multi-agent systems.To implement the consensus algorithm,a sufficient condition for feasible solutions of the SOREs is first established in terms of Lyapunov and Selvester equations.Then the time-varying SOREs are approximated by the Euler-Maruyama method combined with an a-posteriori partial estimation of the increments of the Brownian motion.A numerical example illustrates the theoretical results.

Semi-global weighted output average tracking of discrete-time heterogeneous multi-agent systems subject to input saturation and external disturbances

In this paper,we revisit the semi-global weighted output average tracking problem for a discrete-time multi-agent system subject to input saturation and external disturbances.The multi-agent system consists of multiple heterogeneous linear systems as leader agents and multiple heterogeneous linear systems as follower agents.We design both the state feedback and output feedback control protocols for each follower agent.In particular,a distributed state observer is designed for each follower agent that estimates the state of each leader agent.In the output feedback case,state observer is also designed for each follower agent to estimate its own state.With these estimates,we design low gain-based distributed control protocols,parameterized in a scalar low gain parameter.It is shown that,for any bounded set of the initial conditions,these control protocols cause the follower agents to track the weighted average of the outputs of the leader agents as long as the value of the low gain parameter is tuned sufficiently small.Simulation results illustrate the validity of the theoretical results.

A unified approach to output synchronization of heterogeneous multi-agent systems via L2-gain design

In this paper, a unified design procedure is given for output synchronization of heterogeneous multi-agent systems （MAS） on communication graph topologies, using relative output measurements from neighbors. Three different control protocols, namely, full-state feedback, static output-feedback, and dynamic output-feedback, are designed for output synchronization. It is seen that a unified design procedure for heterogeneous MAS can be given by formulation and solution of a suitable local L2-gain design problem. Sufficient conditions are developed in terms of stabilizing the local agents＇ dynamics, satisfying a certain small-gain criterion, and solving the output regulator equations. Local design procedures are presented for each agent to guarantee that these sufficient conditions are satisfied. The proposed control protocols require only one copy of the leader＇s dynamics in the compensator, regardless of the dimensions of the outputs. This results in lower-dimensional compensators for systems with high-order outputs, compared to the p-copy internal model approach. All three proposed control protocols are verified using numerical simulations.

Containment control for heterogeneous nonlinear multi-agent systems under distributed event-triggered schemes

We study the contain men t cont rol problem for high-order het erogeneous nonlinear multi-age nt systems under distributed event-triggered schemes.To achieve the containment control objective and reduce communication consumption among agents,a distributed event-triggered control scheme is proposed by applying the backstepping method,Lyapunov functional approach,and neural networks.Then,the results are extended to the self-triggered control case to avoid continuous monitoring of state errors.The developed protocols and triggered rules ensure that the output for each follower converges to the convex hull spanned by multi-leader signals within a bounded error.In addition,no agent exhibits Zeno behavior.Two numerical simulations are finally presen ted to verify the correctness of the obtained results.

Consensus Problem of Heterogeneous Multi-agent Systems with Time Delay under Fixed and Switching Topologies

Consensus problem is investigated for heterogeneous multi-agent systems composed of first-order agents and second-order agents in this paper. Leader-following consensus protocol is adopted to solve consensus problem of heterogeneous multi-agent systems with time-varying communication and input delays. By constructing Lyapunov-Krasovkii functional, sufficient consensus conditions in linear matrix inequality(LMI) form are obtained for the system under fixed interconnection topology. Moreover, consensus conditions are also obtained for the heterogeneous systems under switching topologies with time delays. Simulation examples are given to illustrate effectiveness of the results.

Stability Analysis and Group Consensus Tracking Predictive Control of Multi-Agent Systems

The issue of stability and group consensus tracking is investigated for the discrete-time heterogeneous networked multi-agent systems with communication constraints(e.g.,time delays and data loss)in this paper.Firstly,the couple-group consensus tracking control is analyzed theoretically,the communication constraints are compensated by the prediction method,and the factor of leaders is introduced to make the system not lose generality.Secondly,the necessary and sufficient condition is given to ensure the stability of the system and achieve the couple-group consensus tracking control,and relax the topology constraint of in-degrees balance by cooperative-competitive interactions.In addition,the result of couple groups is extended to multiple groups based on the predictive control protocol.Numerical simulations with Matlab show that the proposed networked predictive control can effectively overcome the network constraints,the dynamic performance and control effect are better than the general control without the prediction.

Distributed Event-Triggered Tracking Control of Heterogeneous Discrete-Time Multi-Agent Systems with Unknown Parameters

In this paper,a novel design framework is developed to solve the cooperative tracking problem of heterogeneous discrete-time multi-agent systems with unknown agent parameters and directed communication topologies.First,a distributed event-triggered observer is developed to handle the heterogeneity of the multi-agent systems.An event-triggering mechanism is proposed to reduce the amount of data transmission between neighboring agents.Then,based on the proposed observer,a discrete-time distributed model reference adaptive controller is presented to deal with the unknown parameters of the multi-agent systems.It is shown that by using the proposed observer and the model reference adaptive controller,the proposed design framework could achieve output tracking of the unknown multi-agent systems for any communication graph containing a directed spanning tree.Finally,an example is presented to illustrate the effectiveness of the proposed controller.

Meso-design of heterogeneous dielectric material systems:Structure property relationships

Heterogeneous materials are inherently dielectric,and charge distribution and transport in such materials involves complex local fields and polarizations that are remarkably sensitive to morphology and the interaction of conduction and permittivity.Trial and error design of such material systems is time consuming and expensive,and often ineffectual.However,heterogeneous materials are essential for energy conversion and storage,and they have become the foundation for major advances in the performance of devices such as batteries,fuel cells,separation membranes,and solar cells.The present paper presents some relationships in support of rational design based on an extensive experimental validation of the concepts and analysis that form a foundation for that design.Salient results include the prediction and confirmation of volume fraction effects(including nondilute mixtures),and the prediction and direct measurement of surface charge effects at internal interfaces as a function of constituent morphology and orientation.

Consensus for Heterogeneous Multi-Agent Systems with Directed Network Topologies

In this paper, the consensus problem for heterogeneous multi-agent systems composed of first-order and second-order agents is investigated with directed network topologies. Based on a system transformation method, this consensus problem is turned into a consensus problem for homogeneous multi-agent systems. With certain assumption on the control parameters, firstly, necessary and sufficient condition for consensus is proposed with fixed topology. Secondly, sufficient condition is proposed for heterogeneous multi-agent systems to achieve consensus with switching topologies. Finally, simulation examples are presented to verify the effectiveness of the theoretical results.

Dawning Nebulae:A PetaFLOPS Supercomputer with a Heterogeneous Structure

Dawning Nebulae is a heterogeneous system composed of 9280 multi-core x86 CPUs and 4640 NVIDIA Fermi GPUs. With a Linpack performance of 1.271 petaFLOPS, it was ranked the second in the TOP500 List released in June 2010. In this paper, key issues in the system design of Dawning Nebulae are introduced. System tuning methodologies aiming at petaFLOPS Linpack result are presented, including algorithmic optimization and communication improvement. The design of its file I/O subsystem, including HVFS and the underlying DCFS3, is also described. Performance evaluations show that the Linpack efficiency of each node reaches 69.89%, and 1024-node aggregate read and write bandwidths exceed 100 GB/s and 70 GB/s respectively. The success of Dawning Nebulae has demonstrated the viability of CPU/GPU heterogeneous structure for future designs of supercomputers.

H_(∞)-PID distributed control for output leader-tracking and containment of heterogeneous MASs with external disturbances

This paper addresses both the output leader-tracking and output containment control prob-lems for heterogeneous linear high-order Multi-Agent Systems(MASs)sharing information over a directed communication topology and subject to external unknown disturbances.To solve these control problems,we propose a robust fully distributed Proportional-Integral-Derivative(PID)control strategy,equipped with a filter on the derivative action that allows obtaining both a simpler closed-loop formulation,without the need of the descriptor transformation,and good tracking performances in the case of fast reference signal behaviours.The stability analysis is analytically proven via the Lyapunov theory and the H_(∞) approach.The derived robust stability conditions are expressed as a set Linear Matrix Inequalities(LMIs)whose solution provides the proper tuning of the robust PID control gains.Numerical simulations confirm the effectiveness and robustness of the proposed approach in solving both the output leader-tracking and output containment control problems.