Projective synchronization of a hyperchaotic system via periodically intermittent control

We further study the projective synchronization of a new hyperchaotic system. Different from the most existing methods, intermittent control is applied to chaotic synchronization in the present paper. We formulate the intermittent control system that governs the dynamics of the projective synchronization error, then derive the sufficient conditions for the exponential stability of intermittent control system by using the Lyapunov stability theory, and finally establish the periodically intermittent controller according to the stability criterion by which the projective synchronization is expected to be achieved. The analytical results are also demonstrated by several numerical simulations.

Flow Control with Intermittent Disturbance for the Laminar Separation Bubble on a NACA633-421 Airfoil

This study investigates the aerodynamic performance of the NACA 633-421 airfoil and the effectiveness and feasibility of intermittent disturbance flow control methods on laminar separation bubbles(LSBs).It is found that the average velocity and influence range of the synthetic jet actuator increase with the increasing of driving frequency and driving amplitude.LSB occurs at Re=1.0×10^(5),and ruptures atα=6°.But with intermittent disturbance control,the stall angle of attack(AoA)increases while significantly reducing drag.Research shows that although certain disturbance cannot fully recover from LSB stall,decreasing driving amplitude partially restores wing aerodynamic performance,more effectively than increasing driving amplitude.

Fixed-time distributed robust optimization for economic dispatch with event-triggered intermittent control

This paper proposes a fixed-time distributed robust optimization approach for solving economic dispatch problems.Based on an integral sliding mode control scheme,the proposed multi-agent system converges to an optimal solution to an economic dispatch problem before a fixed time.In addition,the proposed multi-agent system can suppress the disturbance in a fixed time.To reduce the cost of sliding mode controls,we propose a distributed event-triggered intermittent control which reduces the sliding mode control time by setting a control triggering rule on the basis of two boundary functions of a Lyapunov function.The simulation results of three power systems illustrate the characteristics and effectiveness of the theoretical results.

Synchronization of Complex Networks with Coupling Delays via Adaptive Pinning Intermittent Control

The problem of exponential synchronization for a class of general complex dynamical networks with nonlinear coupling delays by adaptive pinning periodically intermittent control is considered in this paper. We use the methods of the adaptive control, pinning control and periodically intermittent control. Based on the piecewise Lyapunov stability theory, some less conservative criteria are derived for the global exponential synchronization of the complex dynamical networks with coupling delays. And several corresponding adaptive pinning feedback synchronization controllers are designed. These controllers have strong robustness against the coupling strength and topological structure of the network. Using the delayed nonlinear system as the nodes of the networks, a numerical example of the complex dynamical networks with nonlinear coupling delays is given to demonstrate the effectiveness of the control strategy.

Exponential Synchronization of Master-Slave Lur'e Systems via Intermittent Time-Delay Feedback Control

This paper concerns with the master-slave exponential synchronization analysis for a class of general Lur'esystems with time delay.Different from the previous methods based on the differential inequality technique, a newapproach is proposed to derive some new exponential synchronization criteria.The restriction that the control widthhas to be larger than the time delay is removed.This leads to a larger application scope for our method.Moreover, notranscendental equation is involved in the obtained result, which reduces the computational burden.Two examples aregiven to validate the theoretical results.

Finite-Time Quasi-Synchronization of Two Nonidentical Chaotic Systems via Intermittent Control

This paper investigates the finite-time quasi-synchronization of two nonidentical Lur'e systems with parameter mismatches by using intermittent control. Based on Lyapunov stability theory and some differential inequality techniques, sufficient conditions for finite-time quasi-synchronization are derived and the explicit expression of error level is obtained. Meanwhile, a numerical simulation is given to illustrate the effectiveness of the theoretical results.

Exponential synchronization for neural networks with mixed time-varying delays via periodically intermittent control

This paper deals with exponential synchronization for a class of neural networks with mixed time-varying delays via periodically intermittent control. Some novel and effective exponential synchronization criteria are derived by constructing Lyapunov functional and applying some analysis techniques. These results presented in this paper generalize and improve many known results. Finally, this paper presents an illustrative example and uses the simulated results to show the feasibility and effectiveness of the proposed scheme.

Fixed-Time Synchronization of Complex Networks via Intermittent Control Without Sign Function

This paper investigates the fixed-time synchronization problem of complex networks.A novel switching controller is proposed to solve the problem.The designed controller in this paper only needs intermittently to pin a few of nodes,which could reduce the control time and save the system’s energy.Moreover,compared with the existing control methods for the fixed-time synchronization,the novel controller does not use the sign function,which could avoid the chattering behaviors.By constructing a Lyapunov function and designing a comparison system,some sufficient conditions are obtained to achieve the fixed-time synchronization.Finally,the numerical simulations could verify the effectiveness and feasibility of the proposed control approaches.

Dynamic modeling and aperiodically intermittent strategy for adaptive finite-time synchronization control of the multi-weighted complex transportation networks with multiple delays

The idea of network splitting according to time delay and weight is introduced.Based on the cyber physical systems(CPS),a class of multi-weighted complex transportation networks with multiple delays is modeled.The finite-time synchronization of the proposed complex transportation networks model is studied systematically.On the basis of the theory of stability,the technique of adaptive control,aperiodically intermittent control and finite-time control,the aperiodically intermittent adaptive finite-time synchronization controller is designed.The controller designed in this paper is beneficial for understanding the synchronization in multi-weighted complex transportation networks with multiple delays.In addition,the conditions for the existence of finite time synchronization have been discussed in detail.And the specific value of the settling finite time for synchronization is obtained.Moreover,the outer coupling configuration matrices are not required to be irreducible or symmetric.Finally,simulation results of the finite-time synchronization problem are given to illustrate the correctness of the results obtained.

Task-Space Tracking Control of Robotic Manipulator Via Intermittent Controller

An intermittent controller for robotic manipulator in task space was developed in this paper.In task space,for given a desired time-varying trajectory,the robot end-effector can track the desired target under the designed intermittent controller.Different from most of the existing works on control of robotic manipulator,the intermittent control for robotic manipulator is discussed in task space instead of joint space.Besides,the desired trajectory can be time-varying and not limited to constant.As a direct application,the authors implemented the proposed controller on tracking of a two-link robotic manipulator in task space.Numerical simulations demonstrate the effectiveness and feasibility of the proposed intermittent control strategy.

APPLICATIONS OF NONLINEAR MEASURE ABOUT l^2-NORM TO SYNCHRONIZATION ANALYSIS OF COMPLEX NETWORKS VIA THE GENERAL INTERMITTENT CONTROL

Based on the nonlinear measure about /-norm,a novel and effective approach is applied to estimate the scope of state vectors of dynamic systems.By the general intermittent control,some simple yet generic criteria are derived ensuring the exponential stability of dynamic systems.The numerical simulations,whose theoretical results are applied to robust synchronization of complex networks,demonstrate the effectiveness and feasibility of the proposed technique.

Post-operative strabismus control and motor alignment for basic intermittent exotropia

AIM：To assess strabismus control and motor ocular alignment for basic exotropia surgery at 5y follow-up.METHODS：The medical records of 80 consecutive patients aged less than 17 years of age,who underwent surgery for basic exotropia by a single surgeon between years 2000 to 2009 and completed a minimum of 5y follow-up post-operatively were reviewed.Pre- and post-operative characteristics were documented at 1wk,6mo,1,3 and 5y follow-up.Subjects at 5-year follow-up were assigned to the success group if they had a postoperative angle of deviation within 10 prism diopters of exotropia or within 5 prism diopters of esotropia for distance on prism cover test,and had moderate to good strabismus control.The remaining subjects were assigned to the failure group.RESULTS：Post-operative surgical success at one week was 75%,which decreased to 41% at 5y follow-up.The success group was noted to have more patching pre-operatively（P=0.003）.The duration of patching a day（P=0.020） and total duration of patching preoperatively（P=0.030） was higher in the success group.Surgical success at 1y（P=0.004） and 3y（P=0.002） were associated with higher surgical success at 5y follow-up.CONCLUSION：Post-operative motor alignment and strabismus control for basic exotropia surgery at 1y and beyond is associated with higher exotropia surgery success at 5-year follow-up.There is an association between pre-operative patching and 5-year surgical success of basic intermittent exotropia surgery.

Cluster synchronization in community network with nonidentical nodes via intermittent pinning control

In this paper, cluster synchronization in community network with nonidentical nodes is investigated. By combining intermittency with a pinning control scheme, some effective controllers are designed. In the control scheme, only one node in each community is controlled and coupling weights of a spanning tree in each community are enhanced. Based on the Lyapunov function method and mathematical analysis technique, two results for achieving cluster synchronization are obtained. Noticeably, by introducing an adaptive strategy, some universal adaptive intermittent pinning controllers are designed for different networks. Finally, two numerical simulations are performed to verify the correctness of the derived results.

Suppression of spiral waves using intermittent local electric shock

In this paper, an intermittent local electric shock scheme is proposed to suppress stable spiral waves in the Barkley model by a weak electric shock （about 0.4 to 0.7） imposed on a random selected n × n grids （n =1 - 5, compared with the original 256×256 lattice） and monitored synchronically the evolutions of the activator on the grids as the sampled signal of the activator steps out a given threshold （i.e., the electric shock works on the n ~ n grids if the activator u ≤ 0.4 or u ≥ 0.8）. The numerical simulations show that a breakup of spiral is observed in the media state evolution to finally obtain homogeneous states if the electric shock with appropriate intensity is imposed.

Observer-Based Intra-Cluster Lag Consensus of Multi-Agent Systems via Intermittent Adaptive Pinning Control

The intra-cluster lag consensus means that the agents in the same cluster can achieve lag consensus asymptotically while the agents in different clusters can achieve different consensus.In this paper,the authors investigate the observer-based intra-cluster lag consensus problems of multi-agent systems(MASs)with general linear dynamics and nonlinear dynamics via intermittent adaptive pinning control.The interaction network is considered to be weakly connected,i.e.,it is not necessary to be strongly connected,in-degree balanced or contain a directed spanning tree.To realise the intra-cluster lag consensus,a class of observers is designed to estimate the states of followers.Then a class of observer-based intermittent adaptive pinning control protocols is proposed according to the difference that the agents receive information source.Moreover,the pinning gains are designed to be intermittent adaptive and have an exponential convergence rate,which will effectively reduce communication costs,avoid the pinning gains being larger than those needed in real applications and guarantee the pinning gains quickly converge to steady value.Correspondingly,some sufficient consensus criteria are derived and rigorous proofs are given based on matrix theory and Lyapunov stability theory.Finally,the effectiveness for the proposed intermittent adaptive pinning control strategy is validated by a numerical simulation.

Scaled Bipartite Consensus Controller Design for Second-Order Multi-Agent Systems with Mixed Time-Delays

The scaled bipartite consensus of second-order multi-agent systems is investigated in this paper.The internal delay and distributed delay are also considered in the dynamic model of each agent,in which the delays can be time-varying and large.The communication topology among agents is assumed to be directed and structurally balanced.On one hand,in order to guarantee scaled bipartite consensus of second-order multi-agent systems,an adaptive periodically intermittent control protocol is applied.On the other hand,some consensus criteria in the form of matrix inequalities are obtained by using Jensen inequality,Lyapunov stability theory and graph theory.Finally,a numerical simulation example is given to demonstrate the feasibility of theoretical results.