Influence Of Communication Delay Research Articles

Output-constrained fixed-time coordinated control for multi-agent systems with event-triggered and delayed communication

In this study, we propose a fixed-time coordinated controller for high-order multi-agent systems dealing with output constraints and switching digraphs while considering event-triggered and delayed communication. To tackle the scenario where only a subset of agents have direct access to the leader, a novel event-triggered fixed-time observer is first devised. This observer effectively estimates the state of the leader, considering the influence of communication delays. Subsequently, a neural network-based fixed-time controller is formulated under output constraints, utilizing the estimated leader commands to achieve the desired control objectives. Finally, practical experiments are conducted using omni-mecanum-wheeled robots to demonstrate the practical feasibility and superior performance of the theoretical findings. This study contributes significantly by tackling the challenging problem of output-constrained fixed-time coordinated control in event-triggered and delayed communication within switching digraphs. This area has yet to be previously explored.

Research on the stability of virtual coupling train formation based on a PID controller under the influence of time delay

Abstract As the latest research direction of train-to-train communication, virtual coupling train formation technology has attracted the attention of many scholars. This paper studies the influence of time delay on the formation of virtual coupled trains. We proposed a distributed PID controller, which means that trains can still form a stable fleet operation under the influence of communication delay and control delay. After modelling and analysis, the research uses Matlab to conduct simulation, involving two sets of experiments. Factors including speed, acceleration, position, position error, expected distance between adjacent trains and actual distance between adjacent trains are simulated. The results demonstrate that the distributed PID controller can effectively control the impact of time delay on the virtual coupling fleet.

Emergence of bipartite flocking behavior for Cucker-Smale model on cooperation-competition networks with time-varying delays

This paper explores the collective behavior of bipartite flocking for a set of autonomous mobile agents based on Cucker-Smale update rules on directed cooperation-competition networks. In our model, cooperative or competitive degree between neighbouring agents is set by a nonlinear function of the communication distance between agents, which is called weight function, and further the influence of communication delays on the system stability and the final distance between agents is analyzed. With the help of related conclusions about sub-stochastic matrices, a sufficient condition relying on the topology structure, weight functions and initial states is established to guarantee the realization of bipartite flocking behavior. In the end the effectiveness of dynamic results is verified through a numerical example.

Distributed Adaptive Fault-Tolerant Control for Heterogeneous Multiagent Systems With Time-Varying Communication Delays

This article considers the distributed adaptive fault-tolerant control problem for heterogeneous linear multiagent systems with actuator faults and nonuniform time-varying communication delays. First, novel distributed switching observers are proposed to estimate the system matrix and the state of the exosystem. The observers allow each agent to share its information with its underlying neighbors only at sampled instants of time, thus making a distinct difference from the existing results that require the exosystem matrix to be accessible to all agents at every continuous instant of time. Second, a sufficient condition is derived such that the observer error systems are exponentially stable under the influence of communication delays among interacting agents. Third, new distributed adaptive fault-tolerant controllers, which promise fewer adaptive parameters, are presented to compensate for the actuator faults. It is shown that the developed controllers are capable to effectively and efficiently solve the cooperative fault-tolerant output regulation problem with reduced computational complexity. Finally, three illustrative examples, including an inverted pendulum system, an electronic double-integrator circuit system, and an AC microgrid system, are presented to show the validity and efficiency of the developed method.

Distributed adaptive robust H ∞ control of intelligent‐connected electric vehicles platooning subject to communication delay

With an aim to improve the performances of intelligent-connected electric vehicle platoon with communication delay, we present a distributed adaptive robust H ∞ control scheme in this paper. First, the longitudinal non-linear dynamic model of vehicle i is established, and in order to reduce the difficulty of analysing such a non-linear system, a simplified uncertain dynamic model of vehicle i is obtained via a feedback linearisation method. Second, a novel distributed state-feedback robust platoon controller is designed by using the relative information between neighbouring electric vehicles. Third, we derive the sufficient condition that the presented distributed robust platoon controller exists under the influence of communication delay. This condition is given in the form of a linear matrix inequality, which is low dimensional and whose dimension is independent of the length of the intelligent electric vehicle platoon. Furthermore, the closed-loop platoon system controlled by the presented controller is proved stable subject to communication delay by using the Lyapunov stability theory. In addition, an adaptive control term is added to the robust platoon controller. We present the sufficient condition that such a modified controller exists and prove the platoon string stability. Finally, the effectiveness of the presented adaptive robust platoon control scheme is verified by conducting numerical simulation tests.

Cooperative Pursuit Control for Multiple Underactuated Underwater Vehicles with Time Delay in Three-Dimensional Space

SUMMARYIn this paper, the k-valued logic control network is introduced to study the cooperative pursuit control problem of multiple underactuated underwater vehicles (UUVs) with time delay in three-dimensional space. The semi-tensor product of matrices is used to solve the complex calculation problem of the large dimension matrix. The influence of communication delay on multiple UUVs’ optimization and cooperative pursuit control is expressed in a matrix. Under the leadership of evader UUV, the control algorithm can ensure that all the pursuit UUVs reach the desired position. The stability of the closed loop system is proved.

A Delay-Tolerable Master–Slave Current-Sharing Control Scheme for Parallel-Operated Interfacing Inverters With Low-Bandwidth Communication

Parallel-operated inverters with common dc and ac bus can be used as an interface for dc systems connecting to an ac network. High cost and complicated wiring of communication are the main drawbacks of communication-based current-sharing methods for the parallel systems. Many new communication tools, e.g., power line communication (PLC), Bluetooth, and Zigbee modules, are cheap and require no extra wire connection, but have low communication bandwidth and low data rate, which result in a large communication delay and zero-order-hold period that could cause stability issues if used to transmit control signals. This article presents a method to mitigate the instability issue caused by communication effects, in parallel grid-tied inverter system with master-slave current-sharing control. First, the master-slave current-sharing control scheme is introduced. Then, the influence of communication delay and zero-order-hold on the system is analyzed. And design criterion to reduce the influence of low-bandwidth communication (LBCom) is studied and determined. New approaches, by designing a current reference low-pass filter and a voltage feedforward loop in slave modules, are introduced. The performance of the proposed control structure and design criteria are experimentally verified. With the proposed method, LBCom tools can be applied to systems with master-slave control architecture while keeping the robustness and transient performance, with improved modularity and operation flexibility.

A Remotely Central Dimming System for a Large-Scale LED Lighting Network Providing High Quality Voltage and Current

Standard TRIAC-based dimmers introduce power quality issues especially for a large-scale lighting network. Other existing dimming protocols involve additional wiring systems and/or additional controllers to light emitting diode (LED) drivers. This paper proposes a central dimming system for a large penetration of LED lamps. The dimming system is remotely controlled through a webpage or a desktop application. Dimming is achieved while maintaining high voltage and current quality waveforms, which results in a high power factor and a low input current harmonic distortion. The system does not require additional wiring or specific adjustments to commercial dimmable LED drivers. The system allows scheduling a dimming profile to endorse energy saving. In the proposed dimming system, dimming function is achieved by connecting a voltage source converter (VSC) between the grid and the LED lamps. An advanced feature is added to the VSC dimmer to remotely send/receive messages between the system and the user through a graphical user interface. Thus, the user can communicate with the VSC dimmer by sending commands and receiving feedback information. The influence of communication delay on system stability is analyzed by using small signal models. A VSC dimmer prototype (500 VA/120 V) has been built with a communication module to provide remote control. Experimental results and comparisons between utilizing the TRIAC-based dimmer and the VSC dimmer for dimming function are discussed in the paper.

Hierarchical optimisation strategy in microgrid based on the consensus of multi‐agent system

To improve the automation level of distributed generation, a hierarchical optimisation strategy is proposed in this study. The strategy consists of day-ahead dispatch and scheduling implementation by power control. The energy management framework about the multi-agent system is also designed. Given the collaborative gaming process between microgrid and distributed network, a day-ahead dispatch is used to minimise the general expenses. Moreover, considering security constraints, the secondary control strategy is proposed to realise the precise control of the active power, which is adaptive to voltage inconsistency. Besides, the consensus algorithm is utilised to trace the dispatch target of tie-line power by monitoring power deviation at the point of common coupling. Finally, a series of simulation verifies the effectiveness of the method proposed. The influence of communication delay is also discussed.