Songlin Hu

Event-triggered H ∞ stabilization for networked stochastic systems with multiplicative noise and network-induced delays

This paper is concerned with event-triggered H ∞ stabilization (in the mean square sense) for networked stochastic system with multiplicative noise and network-induced delays. Firstly, a new discrete event-triggered transmission protocol (DETTP) is proposed to reduce the utilization rate of communication bandwidth. The main features of the proposed protocol involve three aspects: (1) it allows the presence of external disturbances and multiplicative noise; (2) it is more general than some existing event-triggered transmission schemes in the deterministic setting; and (3) the minimum inter-event time is implicity defined and is naturally given by the sampling period chosen for the plant. Secondly, under the DETTP, a new closed-loop stochastic networked control system model is established. Remarkably, to facilitate theoretical analysis, the resultant event-based stochastic networked control system is further transformed into a system with two successive delay components in the state, considering the effects of network-induced delays, multiplicative noise and DETTP in a unified framework. By using stochastic system theory, sufficient conditions on the existence of the desired event-based H ∞ state feedback controller are derived such that the resultant event-based stochastic networked control system is exponentially stable in the mean square sense with a prescribed H ∞ performance while reducing the number of sampled-state transmission along the feedback link as much as possible. Thirdly, a co-design algorithm for determining the parameters of the DETTP and the state feedback controller gain matrix are also proposed. Finally, two practical examples are given to illustrate the effectiveness and advantage of the proposed method over some existing results in the literature.

Event-triggered controller design of nonlinear discrete-time networked control systems in T-S fuzzy model

HighlightsWe propose a more general mixed event-triggering communication scheme.Conditions for uniform ultimately bounded stability are derived in the event-triggered fuzzy control framework.A co-design algorithm is developed to design the desired fuzzy controller and event-triggering scheme simultaneously.A premise synchronizer has been delicately constructed to ensure the same premises with uniform time scales in both fuzzy model and fuzzy controller. This article is concerned with event-triggered fuzzy control design for a class of discrete-time nonlinear networked control systems (NCSs) with time-varying communication delays. Firstly, a more general mixed event-triggering scheme (ETS) is proposed. Secondly, considering the effects of the ETS and communication delays, based on the T-S fuzzy model scheme and time delay system approach, the original nonlinear NCSs is reformulated as a new event-triggered networked T-S fuzzy systems with interval time-varying delays. Sufficient conditions for uniform ultimately bound (UUB) stability are established in terms of linear matrix inequalities (LMIs). In particular, the quantitative relation between the boundness of the stability region and the triggering parameters are studied in detail. Thirdly, a relative ETS is also provided, which can be seen as a special case of the above proposed mixed ETS. As a difference from the preceding results, sufficient conditions on the existence of desired fuzzy controller are derived to ensure the asymptotic stability of the closed-loop system with reduced communication frequency between sensors and controllers. Moreover, a co-design algorithm for simultaneously determining the gain matrices of the fuzzy controller and the triggering parameters is developed. Finally, two illustrative examples are presented to demonstrate the advantage of the proposed ETS and the effectiveness of the controller design method.

Finite-time distributed event-triggered consensus control for multi-agent systems

In this paper, we study the finite-time distributed event-triggered consensus control for multi-agent systems. The controllers and the events are designed in a distributed manner, based only on local information. Compared with conventional asymptotic consensus, finite time consensus can reach consensus faster and have better disturbance rejection properties. Thus, we propose a new nonlinear distributed control protocol to achieve finite-time consensus. Moreover, in order to realize the consensus control for multi-agent systems, only the communication between the agent and its local neighbors is needed, therefore, the designed control is essentially distributed. Two sufficient conditions are proposed to reach finite-time consensus for multi-agent systems with fixed and switching network topologies, respectively. Finally, two simulation examples are presented to demonstrate the effectiveness of the theoretical results.

Multi-elite guide hybrid differential evolution with simulated annealing technique for dynamic economic emission dispatch

The orthogonal initialization method is integrated into differential evolution.Modified mutation operator is used to control convergence rate with simulated annealing technique.Entropy diversity method is utilized to adaptively monitor the population diversity.The results show the quality and efficiency of proposed algorithm in DEED problem. This paper proposes an improved multi-objective differential evolutionary algorithm named multi-objective hybrid differential evolution with simulated annealing technique (MOHDE-SAT) to solve dynamic economic emission dispatch (DEED) problem. The proposed MOHDE-SAT integrates the orthogonal initialization method into the differential evolution, which enlarges the population diversity at the beginning of population evolution. In addition, modified mutation operator and archive retention mechanisms are used to control convergence rate, and simulated annealing technique and entropy diversity method are utilized to adaptively monitor the population diversity as the evolution proceeds, which can properly avoid the premature convergence problem. Furthermore, the MOHDE-SAT is applied on the thermal system with a heuristic constraint handling method, and obtains more desirable results in comparison to those alternatives established recently. The obtained results also reveal that the proposed MOHDE-SAT can provide a viable way for solving DEED problems.

Adaptive periodic event-triggered consensus for multi-agent systems subject to input saturation

ABSTRACT This paper investigates the distributed adaptive event-triggered consensus control for a class of nonlinear agents. Each agent is subject to input saturation. Two kinds of distributed event-triggered control scheme are introduced, one is continuous-time-based event-triggered scheme and the other is sampled-data-based event-triggered scheme. Compared with the traditional event-triggered schemes in the existing literatures, the parameters of the event-triggered schemes in this paper are adaptively adjusted by using some event-error-dependent adaptive laws. The problem of simultaneously deriving the controller gain matrix and the event-triggering parameter matrix, and tackling the saturation nonlinearity is cast into standard linear matrix inequalities problem. A convincing simulation example is given to demonstrate the theoretical results.

MODEL-BASED EVENT-TRIGGERED PREDICTIVE CONTROL FOR NETWORKED SYSTEMS WITH DATA DROPOUT ∗

This paper proposes a novel structure of networked control systems (NCSs) with communication logic, which incorporates model-based networked control systems (MB-NCSs), predictive control, and an event-triggered communication scheme into a unified framework to consider the bandwidth reduction of the network communications. Within this framework, first an event-triggered communication scheme at the sensor side is introduced to determine whether or not the sensor measurement should be transmitted to the controller through the imperfect forward paths. Second, at the controller, a model of the plant is used to predict future state behavior of the plant, and based on the predicted state between successful transmission instants, a novel predictive event-triggering scheme is proposed to compress the size of the packetized control signals transmitted from the controller side to the actuator side through feedback paths. Finally, a unified model of NCSs is established. Based on this model, a codesign condition of th...

Fault Estimation Observer Design of Discrete-Time Nonlinear Systems via a Joint Real-Time Scheduling Law

Robust fault estimation (FE) observer designs for discrete-time nonlinear system are deeply discussed via a joint real-time scheduling law. Different from previous results involved in the field, a fresh FE observer is produced by means of intermittently launching a joint real-time scheduling law in the light of updated multi-instant information. Thanks to the overall vision of system information across several adjacent sampled points, less conservative result is favorably acquired. Second, the given result is ulteriorly ameliorated by effectively developing an improved introduction technique of free matrix variables. Finally, one nonlinear truck-trailer example is employed for validating the superiority of theoretic fruits that is given in this paper.

Fuzzy control design of nonlinear systems under unreliable communication links

In this study, we propose a systematic homogenous polynomial approach for fuzzy control design of discrete-time Takagi-Sugeno fuzzy systems under unreliable communication links. A novel delayed fuzzy control scheme, which is homogenous polynomially parameter-dependent on both the current normalized fuzzy weighting function and the one-step-past normalized fuzzy weighting function, is designed to accomplish the assignment of relaxed control synthesis. In contrast to the existing methods, the closed-loop controlled system is stochastically stable in the mean square sense with less conservative stabilization conditions. Finally, simulation results are provided to verify the advantage and the effectiveness of the proposed approach.

Stabilization of Neural-Network-Based Control Systems via Event-Triggered Control With Nonperiodic Sampled Data

This paper focuses on a problem of event-triggered stabilization for a class of nonuniformly sampled neural-network-based control systems (NNBCSs). First, a new event-triggered data transmission mechanism is designed based on the nonperiodic sampled data. Different from the previous works, the proposed triggering scheme enables the NNBCSs design to enjoy the advantages of both nonuniform and event-triggered sampling schemes. Second, under the nonperiodic event-triggered data transmission scheme, the nonperiodic sampled-data three-layer fully connected feedforward neural-network (TLFCFFNN)-based event-triggered controller is constructed, and the resulting closed-loop TLFCFFNN-based event-triggered control system is modeled as a state delay system based on time-delay system modeling approach. Then, the stability criteria for the closed-loop system is formulated using Lyapunov–Krasovskii functional approach. Third, the sufficient conditions for the codesign of the TLFCFFNN-based controller and triggering parameters are given in terms of solvability of matrix inequalities to guarantee the asymptotical stability of the closed-loop system and an upper bound on the given cost function while reducing the updates of the controller. Finally, three numerical examples are provided to illustrate the effectiveness and benefits of the proposed results.

Discrete-Time Event-Triggered Control of Nonlinear Wireless Networked Control Systems

This paper investigates the problem of stabilization of nonlinear discrete-time networked control systems (NCSs) with event-triggering communication scheme in the presence of signal transmission delay. A Takagi-Sugeno (T-S) fuzzy model and parallel-distributed compensation (PDC) scheme are first employed to design a nonlinear fuzzy event-triggered controller for the stabilization of nonlinear discrete-time NCSs. The idea of the event-triggering communication scheme (i.e., a soft computation algorithm) under consideration is that the current sensor data is transmitted only when the current sensor data and the previously transmitted one satisfy a certain state-dependent trigger condition. By taking the signal transmission delay into consideration and using delay system approach, a T-S fuzzy delay system model is established to describe the nonlinear discrete-time NCSs with event-triggering communication scheme. Attention is focused on the design of fuzzy event-triggered controller which ensures asymptotic stability of the closed-loop fuzzy systems. Linear matrix inequality- (LMI-) based conditions are formulated for the existence of admissible fuzzy event-triggered controller. If these conditions are feasible, a desired fuzzy event-triggered controller can be readily constructed. A nonlinear mass-spring-damper mechanical system is presented to demonstrate the effectiveness of the proposed method.