Publications

This paper is concerned with the distributed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> -consensus filtering problem on attitude tracking over a radar filter network subject to switching topology and random packet dropouts occurring in the data transmission from both the Sun sensor and the filters. Since ground-based radars cannot directly measure the satellite attitude, a Sun sensor is deployed at the satellite side and its measurements are transmitted to radar filters through different network communication channels while suffering from random packet dropouts with different probabilities. In the radar filter network, each radar filter receives data not only from the Sun sensor but also from its local neighboring radar filters in accordance with a switching network topology. A delicate distributed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> -consensus filtering algorithm, which incorporates the effects of switching network topology and random packet dropouts, is adopted to estimate attitude and attitude-rate. The algorithm guarantees H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> -consensus attenuation performance for the estimation deviations among radar filters, and the robustness against the switching network topology and packet dropouts for the radar filter network. The illustrative examples are given to verify the effectiveness of the proposed distributed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> -consensus filtering algorithm.

All eight pangolin species, especially captive Manis pentadactyla, are critically endangered and susceptible to various pathogenic microorganisms, causing mass mortality. They are involved in the complement system, iron transport system, and inflammatory factors. M. pentadactyla exhibited a higher abundance of opportunistic pathogens, Moraxella, which potentially evaded complement-mediated immune response by reducing C5 levels and counteracting detrimental effects through transferrin neutralization. In addition, we found that the major structure of C5a, an important inflammatory factor, was lacking in M. javanica. In brief, this study revealed the differences in immune factors and microbiome between M. javanica and M. pentadactyla, thus providing a theoretical basis for subsequent immunotherapy.

This paper is concerned with distributed event-triggered H∞ consensus filtering for a discrete-time linear system over a sensor network. Different from some existing event-triggered communication schemes (ETCSs), a new distributed ETCS is first developed to reduce the communication frequency of neighboring sensors, where the threshold parameter in an event triggering condition is time-varying with attainable upper and lower bounds. Then a threshold-parameter-dependent approach is proposed to derive criteria for designing the desired H∞ consensus filters and the ETCS such that the resultant filtering error system is asymptotically stable with the prescribed H∞ performance while maintaining satisfactory resource efficiency. Furthermore, a polytope-like transformation with regard to time-varying threshold parameters is performed and a recursive algorithm is presented to determine the threshold-parameter-dependent filter matrix sequences and event triggering weighting matrix sequence. Two illustrative examples are employed to show the effectiveness of the developed approach.

Information flow topology is crucial in the control of connected autonomous vehicles. It substantially influences the platoon's performance. This study provides a real-time switching topology technique for improving the platoon's performance under poor communication. First, a discrete sliding mode controller with a double power reaching law is designed for a nonlinear heterogeneous vehicle dynamic model with packet loss. Then, Lyapunov analysis is applied to ensure the platoon's stability and string stability. Finally, a two-step switching topology framework is introduced. The first step is to search for Pareto optimal topology offline with predicted imperfect communication scenarios. Then, the platoon's overall performance is optimised using a multi-objective evolutionary algorithm. In the second step, the optimal topology is selected and switched in real-time to reduce the control cost. The proposed method maximises the advantages of information flow topology. It deals with poor communication, improves the platoon's performance, and ensures stability. Numerical simulations were conducted to validate the proposed approach. Compared to a standard robust sliding mode controller, the suggested technique enhances platoon tracking ability by 97.73 percent, fuel efficiency by 9.96 percent, and driving comfort by 20.18 percent, respectively.

This chapter deals with the problem of distributed optimizationDistributed optimization for multi-agent systems by using an edge-based fixed-time consensus approach. In the case of time-invariant cost functions, a distributed protocol is proposed to achieve the...

This paper is concerned with the moving horizon estimation problem for a class of discrete time-delay systems under the Round-Robin (RR) protocol. The communication between the sensor nodes and the remote state estimator is implemented via a shared network, where only one sensor node is permitted to transmit data at each time instant for the purpose of preventing data collisions. The RR protocol is utilized to orchestrate the transmission order of sensor nodes, under which the selected node obtaining access to the network could be modeled by a periodic function. A lifting technology is introduced to reformulate the system model into a linear system without delays. The aim of the addressed problem is to develop a moving horizon estimator such that the estimation error is ultimately bounded. A sufficient condition is established to ensure the ultimate boundedness in terms of a matrix inequality. Within the established theoretical framework, two optimization problems are proposed to calculate the corresponding estimator parameters according to two different performance requirements (e.g., the smallest ultimate bound and the fastest decay rate). Finally, simulation examples are given to illustrate the effectiveness of the estimator design scheme.

In this article, as inspired by multiagent systems, a novel leader–follower-based particle swarm optimization (LFPSO) algorithm is presented where the particles are classified into leaders and followers according to their respective roles. The leaders are responsible for searching a wide range of the optimal candidate solutions so as to ensure the diversity of the particle population, and the followers are dedicated to seeking the global-best solution in order to guarantee the convergence of particles. A controller parameter is introduced to fine tune the impact of the leaders on the followers. Owing to the leader–follower mechanism, the proposed LFPSO algorithm not only maintains the diversity of the particle population but also improves the possibility of escaping from the locally optimal solution. It is demonstrated via experimental results that the proposed LFPSO algorithm significantly improves the accuracy and convergence rate of conventional particle swarm optimization algorithms. Furthermore, the LFPSO algorithm is successfully applied to denoise real-time signals in oilfield pipeline network and its superiority over existing denoising algorithms is verified as well.

During the past few decades, networked systems have gained increasing attention and a wider range of applications have been found in areas such as industrial control and signal processing. This paper provides a brief survey of recent results on control and filtering for networked systems. In-depth analysis and discussion is first made on networked control and event-triggered control, where existing research methods on networked control systems are summarized. Then, network-based filtering is also reviewed. Finally, some challenging problems are presented to direct future research.

This paper deals with the co-design problem of event-triggered communication scheduling and platooning control over vehicular ad-hoc networks (VANETs) subject to finite communication resource. First, a unified model is presented to describe the coordinated platoon behavior of leader-follower vehicles in the simultaneous presence of unknown external disturbances and an unknown leader control input. Under such a platoon model, the central aim is to achieve robust platoon formation tracking with desired inter-vehicle spacing and same velocities and accelerations guided by the leader, while attaining improved communication efficiency. Toward this aim, a novel bandwidth-aware dynamic event-triggered scheduling mechanism is developed. One salient feature of the scheduling mechanism is that the threshold parameter in the triggering law is dynamically adjusted over time based on both vehicular state variations and bandwidth status. Then, a sufficient condition for platoon control system stability and performance analysis as well as a co-design criterion of the admissible event-triggered platooning control law and the desired scheduling mechanism are derived. Finally, simulation results are provided to substantiate the effectiveness and merits of the proposed co-design approach for guaranteeing a trade-off between robust platooning control performance and communication efficiency.

This paper is concerned with the event-triggered output feedback ℋ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control for sampled-data control systems with nonuniform sampling. Firstly, an output-based event-triggered communication scheme is proposed, in which the state of the system is sampled with a nonuniform sampling period. Under this scheme, whether or not the sampled data should be transmitted is determined by a predetermined output-based event-triggering condition. Secondly, an event-triggered networked control system is modeled as a time-delay system by taking into consideration the output-error between the output at the current sampling instant and the output at the last transmitted sampling instant. Thirdly, stability and stabilization criteria are derived to guarantee the uniform ultimate bounded stability and the desired performance while using less communication resources. Finally, two illustrative examples are used to show the effectiveness of the proposed method.

This paper is concerned with the H ∞ control problem for a class of linear parameter-varying (LPV) systems with randomly multi-step sensor delays. A

In this chapter, parallel distributed compensation (PDC) fuzzy rules are investigated for Takagi–Sugeno (T-S) fuzzy systems under network environments subject to asynchronous grades of membership.

This paper is concerned with active power sharing and frequency regulation in an islanded microgrid under event-triggered communication. A distributed secondary control scheme with a sampled-data-based event-triggered communication mechanism is proposed to achieve active power sharing and frequency regulation in a unified framework, where neighborhood sampled-data exchange occurs only when the predefined triggering condition is violated. Compared with traditional periodic communication mechanisms, the proposed event-triggered communication mechanism shows some prominent ability in reducing the number of communication among neighbors while guaranteeing the desired performance level of microgirds. By employing the Lyapunov-Kravovskii functional method, some sufficient conditions are derived to characterize the effects of control gains, system parameters, and sampling period on stability of microgrids. Finally, case studies on a modified IEEE 34-bus test system are conducted to evaluate the performance of the proposed distributed control scheme, showcasing its effectiveness, robustness against load changes, and plug-and-play ability.

The robust stability of uncertain linear neutral systems with time-varying discrete and distributed delays is investigated by employing descriptor model transformation and the decomposition technique of discrete-delay term matrix. The proposed delay-dependent stability criteria are formulated in the form of a linear matrix inequality. Numerical examples are given to indicate significant improvements over some existing results.

This paper provides a brief overview of delayed feedback control schemes for offshore structures. Two simplified models of offshore steel jacket structures are listed first. Then based on the dynamic models of offshore structures, several active control strategies including delayed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control and delayed integral sliding mode control by using pure delayed signals and using current as well as delayed signals of the systems are outlined, respectively. Finally, some challenging problems and potential research directions about delayed feedback control for offshore structures are presented.