ZeyuanW

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• Personal Web: https://zswzy.github.io/
• Linkedin: www.linkedin.com/in/zeyuan-wang-9138481b4
• Google Scholar: https://scholar.google.com/citations?user=qKeZr7cAAAAJ&hl=en
• Research Gate: https://www.researchgate.net/profile/Zeyuan-Wang-12

Contact:

• Working Email: zeyuan.wang@universite-paris-saclay.fr
• Personal Email: zeyuan_wang@outlook.com

Cite as:
[1] Z. Wang, M. Chadli, L. Li, S. X. Ding, and K. Liang, “Fault Detection for Heterogeneous Multi-Agent Systems with Unknown Dynamics Using Distributed Autoencoder,” in Proceedings of the 23rd European Control Conference (ECC), Thessaloniki, Greece, June 2025.

Abstract:
This paper presents a novel approach addressing fault detection challenges for multi-agent systems through a machine-learning method using recurrent autoencoders. The main advantage lies in its ability to handle heterogeneous multi-agent systems with unknown dynamics. The approach features a distributed detection architecture based on a cluster representation that depends solely on the agents’ relative outputs, integrating stable image representation and orthogonal projection. Unlike traditional observer-based methods, the fault detection framework employs distributed autoencoders for residual generation, offering a data-driven and model-free solution. The autoencoders are carefully designed for effective timeseries data learning, incorporating gated recurrent units and neural networks. Simulation results validate the effectiveness of the proposed method, demonstrating excellent fault detection capabilities and highlighting the promising extension to more complex and generic systems.

Keywords:
Multi-agent systems, Fault detection, Fault diagnosis, Autoencoder

Cite as:
[1] Z. Wang and M. Chadli, “Distributed event-triggered fault estimation for Takagi–Sugeno multi-agent systems with unmeasurable decision variables,” Journal of the Franklin Institute, vol. 362, no. 8, p. 107689, May 2025, doi: 10.1016/j.jfranklin.2025.107689.

Abstract:
This paper proposes a novel distributed fault estimation framework for a class of nonlinear multi-agent systems (MASs), addressing time-varying multiplicative and additive faults in both actuators and sensors. To address these challenges, the Takagi–Sugeno (T–S) system model is employed, incorporating unmeasurable decision variables, which introduces more complexity compared to known decision variables. This study pioneers the one-sided Lipschitz approach in this context, offering significant advancements over the traditional Lipschitz method. A two-step design process is presented to estimate system states, faults, and external disturbances through an ℓth-order proportional-integral observer and a constrained least squares estimator, which is data-driven. Agents can update their observers by using relative residual outputs derived from neighboring information, enhancing both fault and state estimation accuracy. Furthermore, a dynamic event-triggered communication protocol enables efficient output sharing and reduces communication costs. The observer design conditions are formulated as an optimization problem constrained by linear matrix inequalities, ensuring robust H-infinity performance. Simulation results validate the effectiveness of the proposed method for robust fault estimation in nonlinear MASs.

Keywords:
Multi-Agent Systems, Fault estimation, Event-triggered, T–S systems, Unmeasurable decision variables

Cite as:
Z. Wang and M. Chadli, ‘Event-Triggered Controller Design for Multi-Agent Systems’, in Encyclopedia of Systems and Control Engineering, Elsevier, 2024. doi: 10.1016/B978-0-443-14081-5.00124-0.

Abstract:
This chapter presents an event-triggered controller design for multi-agent systems, where the data transmission among agents is governed by event-triggered mechanisms. The dynamic event-triggered control with the full-state observer is introduced, with a particular concern of reducing communication frequency through designable inter-event time. An extension to directed topology, where the communication is restricted to single directions, is also discussed. The proposed methods follow the co-design principle, where the parameters of controllers, observers, and event-triggered mechanisms are synthesized simultaneously. Following a distributed design principle, only local information is required in a small range of nearby neighbors to compute the control signal and the event-triggered condition. Zeno behavior is proved to be excluded. Finally, the proposed approaches are demonstrated by a numerical example and compared with other methods to validate their effectiveness.

Cite as:
Z. Wang, M. Chadli, and S. X. Ding, ‘A dynamic event-triggered approach for observer-based formation control of multi-agent systems with designable inter-event time’, Systems & Control Letters, vol. 195, p. 105970, Jan. 2025, doi: 10.1016/j.sysconle.2024.105970.

Abstract:
This paper addresses the leader-following formation control problems for generic linear multi-agent systems under directed topology with designable inter-event time. A synthesis approach combining controller and observer design is developed under a dynamic event-triggered communication and control scheme. The proposed feedback control, state estimation, and event-triggered rules are distributed, and only local information is required for each agent to implement these algorithms. The proposed dynamic event-triggered protocol incorporates model-based estimation and clock-like auxiliary dynamic variables to prolong the inter-event time and economize the network resources. Furthermore, the inter-event time is designable, which allows more flexible tuning of communication frequency with only minor performance degradation. Sufficient conditions for formation control are established by linear matrix inequalities. The proposed method exhibits significant improvement over the dynamic event-triggered control methods described in the existing literature. Compared to the existing static event-triggered strategy, the proposed approach significantly reduces the utilization of communication resources while preserving asymptotic convergence to the desired formation. Comparative simulations demonstrate the validity and effectiveness of the proposed theoretical results.

Keywords:
Dynamic event-triggered control, Multi-agent systems, Formation control, Observer-based control, Distributed control, Designable inter-event time

Cite as:
Z. Wang and M. Chadli, ‘Distributed Joint Fault Estimation for Multi-Agent Systems via Dynamic Event-Triggered Communication’, IEEE Control Systems Letters, pp. 1–1, 2024, doi: 10.1109/LCSYS.2024.3405390.

Abstract:
This paper studies a novel distributed fault estimation framework for multi-agent systems under directed topology, subject to time-varying multiplicative and additive faults. Both actuator and sensor faults are simultaneously addressed by introducing an augmented system. A two-step design process is presented aimed at joint estimation of faults, system state, and exogenous disturbance, which involves an $\ell$th-order proportional-integral observer and a constrained least square estimator. Utilizing the relative output of neighbor information enhances the accuracy of fault and state estimation. Output sharing is realized by a dynamic event-triggered communication protocol, which effectively saves network resources. The design conditions of the observer are formulated as an optimization problem subject to linear matrix inequalities, ensuring guaranteed H-infinity performance of not only estimation error but also event error. Simulation results validate the effectiveness and feasibility of the proposed method.

Keywords:
Distributed control, Estimation, Fault diagnosis, Networked control systems

Cite as:
Z. Wang and M. Chadli, ‘A Virtual Actuator and Sensor Approach for Event-Triggered Fault-Tolerant Control of Multi-Agent Systems’, in 12th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes (IFAC Safeprocess 2024), Ferrara, Italy: IEEE, Jun. 2024, p. (In presse).

Abstract:
The increasing emphasis on system safety and reliability has heightened the demand for fault-tolerant ability of control systems. Fault-tolerant cooperative control (FTCC) is one of the safety issues in multi-agent systems (MASs). This paper studies the leader-following consensus control of MASs in the presence of actuator and sensor faults. A unified framework of active FTCC is proposed under a dynamic event-triggered mechanism (DETM) by employing the virtual actuator and virtual sensor approach. The proposed DETM serves to reduce the communication cost among agents. The FTCC issue is formulated by linear matrix inequalities (LMIs) and can be implemented in a distributed architecture. Without the need of re-tuning the pre-designed observer-based controller, the FTCC exhibits a notable efficiency for fault compensation and plant reconfiguration. Numerical simulations demonstrate the validity of the proposed methods.

Keywords:
Multi-Agent Systems, Fault-Tolerant Control, Event-Triggered Control, Virtual Actuator, Virtual Sensor, LMI approach, Networked System

Cite as:
Z. Wang and M. Chadli, ‘Observer‐based distributed dynamic event‐triggered control of multi‐agent systems with adjustable interevent time’, Asian Journal of Control, p. asjc.3385, Apr. 2024, doi: 10.1002/asjc.3385.

Abstract:
In this paper, a novel dynamic event‐triggered control protocol for leader‐following problems of generic linear multi‐agent systems is proposed. Compared with the existing static event‐triggered strategy, the developed event‐triggered approach significantly reduces the utilization of communication resources while guaranteeing asymptotic consensus, and the interevent time is adjustable. Under this event scheduling mechanism, a synthesis approach combining controller and observer design is presented. The observer‐based control and event‐triggered rules are distributed, which only require local information of each agent to implement. The proposed methods incorporate model‐based estimation and auxiliary dynamic variables with a clock‐like behavior to prolong the interevent time as long as possible. The sufficient conditions for leader‐following consensus are established using linear matrix inequalities (LMIs) formulation to facilitate numerical computation. Comparative simulations in different scenarios demonstrate the validity of the proposed theoretical results.

Keywords:
distributed control, dynamic event-triggered control, leader-following consensus, multi-agent systems, observer-based control

Cite as:
Z. Wang and M. Chadli, “Improved Dynamic Event-Triggered Consensus Control for Multi-Agent Systems with Designable Inter-Event Time*,” 2023 31st Mediterranean Conference on Control and Automation (MED), Limassol, Cyprus, 2023, pp. 818-823, doi: 10.1109/MED59994.2023.10185702.

Abstract:
This paper considers the leader-following consensus control for linear multi-agent systems. Two improved dynamic event-triggered control frameworks are proposed. The first one is based on a moving average approach, whereas the second is a fully-distributed control scheme based on a well-chosen Lyapunov function with rigorous proof of adjustable inter-event time. The proposed methods involve model-based estimation and clock-like auxiliary dynamic variables to increase the inter-event time as long as possible eventually. Compared to the static event-triggered strategy and the existing state-of-the-art dynamic event-triggered mechanism, the proposed approach significantly reduces the communication frequency while still guaranteeing asymptotic convergence. Numerical simulations demonstrate the validity of the proposed theoretical results.

Keywords:
Multi-agent systems, Leader-following consensus, Dynamic event-triggered control, LMI, Designable inter-event time.

Cite as:
Wang Z, Chadli M. Dynamic Event-triggered Control for Multi-agent Systems with Adjustable Inter-event Time: a Moving Average Approach.

Abstract:
This extended abstract presents our recent work on the leader-following consensus control for generic linear multi-agent systems. An improved dynamic event-triggered control framework are proposed, based on a moving average approach. The proposed methods involve model-based estimation and clock-like auxiliary dynamic variables to increase the inter-event time as long as possible eventually. Compared to the static event-triggered strategy and the existing state-of-the-art dynamic event-triggered mechanism, the proposed approach significantly reduces the communication frequency while still guaranteeing asymptotic convergence. Numerical simulations demonstrate the validity of the proposed theoretical results.

Keywords:
Multi-agent systems, Leader-following consensus, Dynamic event-triggered control, Moving average.