Adaptive finite-time event-triggered command filtered control for nonlinear systems with unknown control directions

Nonlinear Dynamics - In this article, we study an adaptive finite-time event-triggered command filtered control problem based on output feedback for a class of nonstrict-feedback nonlinear systems...     

Event-triggered output feedback control for feedforward nonlinear systems with unknown measurement sensitivity

Nonlinear Dynamics - This paper investigates the event-triggered output feedback control problem for feedforward nonlinear systems with unknown measurement sensitivity. The nonlinear terms are...     

Dissipative control of switched nonlinear systems with sliding mode: an event-triggered control scheme

This paper introduces the event-triggered scheme to study the problems of dissipative control and dissipativity-based sliding mode control (SMC) for switched nonlinear systems. Firstly, based on a designed event-triggered scheme, a piecewise continuous state feedback controller is constructed; sufficient conditions for \(\left( Q,S,R\right) \)-\(\alpha \)-dissipativity of the resulting system are derived by the approaches of a switched Lyapunov function and an average dwell time. Secondly, these two methods are extended to the study of \(H_\infty \) performance and passive performance; the corresponding sufficient conditions are provided. Thirdly, the dissipative control problem is solved by introducing an event-triggered scheme into SMC method. Sufficient conditions for dissipativity of the resulting system are derived, and an SMC law is designed to guarantee the reachability. At the end of this paper, the correctness of the proposed methods is proved by two numerical examples.

     

Integral-based event-triggered synchronization criteria for chaotic Lur’e systems with networked PD control

Integral-based event-triggered synchronization criteria are firstly presented for networked chaotic systems with proportional-derivative (PD) control. The event-triggered scheme effectively utilizes network resources; however, the PD-type control subject to the conventional triggering inequality may cause excessive triggering and have difficulty in obtaining a feasible solution. To solve these problems, the integrated event-triggering inequality is employed and the modified integral inequality with free-weighting matrix is proposed to fill the empty diagonal terms, which overcomes the difficulties of the integration of delayed signal vectors upon integral event-triggering condition. Based on Lyapunov stability, the synchronization criteria are derived as linear matrix inequalities. Finally, the effectiveness of the integral-based event-triggered synchronization method is demonstrated by numerical examples.     

Event-triggered output-feedback tracking of a class of nonlinear systems with unknown time delays

A single function approximation (SFA) approach for event-triggered output-feedback tracker design is presented for uncertain nonlinear time-delay systems in lower-triangular form. Contrary to the existing event-triggered output-feedback control methods dependent on multiple function approximators in the presence of lower-triangular nonlinearities, the proposed SFA approach provides the following advantages: (i) the simple observer structure independent of function approximators; (ii) one event-triggering condition based on only a tracking error; and (iii) the simple control scheme using one function approximator. Thus, the structural simplicity is allowed for implementing the observer and the event-triggering law in the sensor part and the adaptive tracker in the control part. Under the proposed SFA-based event-triggered control scheme, it is shown that the boundedness of closed-loop signals and the existence of a minimum inter-event time are guaranteed regardless of unknown time-delay nonlinearities and unmeasurable state variables.

     

Leaderless maneuver guidance and event-triggered formation control for distributed multi-space-robot systems

In this paper, the distributed displacement-based formation and leaderless maneuver guidance control problems of multi-space-robot systems are investigated by introducing event-triggered control update mechanism. A distributed formation and leaderless maneuver guidance control framework is first constructed, which includes two parallel controllers, namely an improved linear quadratic regulator and a distributed consensus-based formation controller. By applying this control framework, the desired formation configuration of multi-space-robot systems can be achieved and the center of leaderless formation can converge to the target point globally. Second, a pull-based event triggering mechanism is introduced to the distributed formation controller, which makes the control update independent of the events of neighboring robots, avoids unnecessary control updates, and saves the extremely limited energy of space robots. Furthermore, the potential Zeno behaviors have been excluded by proving a positive lower bound for the inter-event times. Finally, numerical simulation verifies the effectiveness of the theoretical results.

     

基于状态观测器的带分布参数体系地震响应控制

针对带分布参数体系地震响应控制问题,建立带分布参数体系的运动控制方程,推导出应用于带分布参数体系的序列最优模态控制算法。根据序列最优模态控制算法振动控制时对结构全状态反馈的需要,提出了针对序列最优模态控制算法的全维状态观测器,形成基于全维状态观测器的序列最优模态控制算法,然后通过测量容易测量的结构地震响应,由全维状态观...     

Event-triggered finite-time resilient control for switched systems: an observer-based approach and its applications to a boost converter circuit system model

Under an event-triggered communication scheme (ETCS), this note focuses on the observer-based finite-time resilient control problem for a class of switched systems. Different from the existing finite-time problems, not only the problem of finite-time boundedness (FTBs) but also the problem of input-output finite-time stability (IO-FTSy) are considered in this paper. To effectively use the network resources, an ETCS is formulated for switched systems. Considering that not all the states could be measured, thus an event-triggered observer is constructed, and then, an observer-based resilient controller is devised, which robustly stabilizes the given systems in the meaning of finite-time control. Based on time-delay method and Lyapunov functional approach, interesting results are derived to verify the properties of the FTBs and the IO-FTSy of the event-triggered (ET) closed-loop error switched systems. All the matrix inequalities can be converted to linear matrix inequalities (LMIs) so as to simultaneously obtain the controller gain and observer gain. Finally, the applicability of the proposed control scheme is verified via a boost converter circuit system.     

Collective stochastic resonance behavior in the globally coupled fractional oscillator

This paper investigates the exponential synchronization of chaotic Lur’e systems (CLSs) with time-varying communication delays through event-triggered sampling control. Specially, first, a discrete event-triggered sampling control scheme, which only sends necessary sampling signal through the network, is designed for CLSs. By using this controller, the number of control updates could greatly reduce. Second, by getting utmost out of the usable information on the actual sampling pattern, some new sawtooth structure terms are introduced in the constructed Lyapunov–Krasovskii functional (LKF). It is worth mentioning that, different from some existing results to restrict the LKF to be positive define on the whole sampling intervals, the LKF is positive definite only needing at sampling times thanks to the use of the new inequality in Lemma 1. Third, less conservative synchronization criteria are established and the desired control gain matrix is obtained. Finally, two Chua’s circuit numerical simulations are presented to validate the feasibility and effectiveness of the theoretical results.     

Observer-based dissipative output feedback control for network T–S fuzzy systems under time delays with mismatch premise

Nonlinear Dynamics - This paper deals with the problem of non-parallel distribution compensation networked control systems (NCSs) under event-triggered strategy based on the fuzzy system for a...     

Event-based secure consensus of multiple AUVs under DoS attacks

In this paper, the event-based triggering method is adopted to investigate the secure consensus issue of multiple autonomous underwater vehicles (AUVs) under denial-of-service (DoS) attacks. DoS attack is a form of time-sequence-based cyber attack, which can destroy the normal service of the control target or network. First, based on an event-triggered mechanism, a novel secure control protocol is proposed. Second, the upper bounds of attack duration and attack frequency are given to ensure that multiple AUVs under DoS attacks can reach consensus. Third, an event-triggered mechanism with exponential variables is developed to avoid the continuous update of the controller, thereby reducing the burdens of communication and calculation. Zeno behavior can be strictly ruled out for each AUV under this triggering mechanism. Finally, the simulation results illustrate the feasibility of the proposed scheme.

     

Active vibration control and suppression for integrated structures

Spacesmictures,aircraftstrUctures,satellitesandsoonarerequiredtobelightinweightduetotherequirementofoperation.TheyarealsolightlydampedbecauseofthelowinternaldampingofthematerialsusedintheirconstrUction.Thus,theywillgeneraiClargeamplitudevibration,whichmayreducetheprecisionofoperationandaffectthePerformanceofoperation.Itisessentialtousesuitablecontrolsystemtocontrolthevibrationofsimctures.Sincethesesmicturesaredistributedparametersystemshavinganinfinitesetofvibrationmodes,thecontrolsystemwith…     

Stabilization control for offshore steel jacket platforms with actuator time-delays

This paper is concerned with the stabilization control for the offshore steel jacket platforms subject to wave-induced force. Two state feedback stabilization control schemes are proposed to reduce the vibration amplitudes of the systems. One scheme is that for the systems without actuator time-delay, a state feedback controller is designed. Compared with the nonlinear controller, both the control force and the vibration amplitudes of the systems under the state feedback controller are much reduced; and compared with the dynamic output feedback controller and the integral sliding mode controller, the required control force under the state feedback controller are significantly reduced. The other scheme is that based on the integral inequality approach, a delay-dependent state feedback controller, which can be solved by using the cone complementarity algorithm, is developed to control the systems with actuator time-delays. Compared with the state feedback controller, the delay-dependent state feedback controller is less conservative with actuator time-delays. In addition, it is capable of improving the control performance of the offshore platforms significantly, which are illustrated by simulation results.     

Event-triggered-based fixed-time adaptive neural fault-tolerant control for stochastic nonlinear systems under actuator and sensor faults

Nonlinear Dynamics - In this paper, the problem of adaptive fault-tolerant control with event-triggered scheme is studied for a class of uncertain stochastic nonlinear systems with the actuator and...     

Periodic decentralized event-triggered control for nonlinear systems with asynchronous update and dynamic quantization

Nonlinear Dynamics - Periodic event-triggered control (PETC) is an aperiodic sampling technique aiming at reducing the working time of the sensors and the transmissions in the feedback control...     

Event-triggered optimal control for nonlinear stochastic systems via adaptive dynamic programming

Nonlinear Dynamics - For nonlinear Itô-type stochastic systems, the problem of event-triggered optimal control (ETOC) is studied in this paper, and the adaptive dynamic programming (ADP)...     

Robust adaptive critic control design with network-based event-triggered formulation

Nonlinear Dynamics - In this paper, by incorporating the network-based event-triggered formulation, the robust adaptive critic control design for a class of nonlinear continuous-time systems is...     

Event-triggered fixed-time adaptive fuzzy control for state-constrained stochastic nonlinear systems without feasibility conditions

Nonlinear Dynamics - The problem of event-triggered fixed-time control for state-constrained stochastic nonlinear systems is discussed in this article. Different from the barrier Lyapunov function...     

Exponential synchronization for second-order nonlinear systems in complex dynamical networks with time-varying inner coupling via distributed event-triggered transmission strategy

This paper focuses on the exponential synchronization problem of complex dynamical networks (CDNs) with time-varying inner coupling via distributed event-triggered transmission strategy. Information update is driven by properly defined event, which depends on the measurement error. Each node is described as a second-order nonlinear dynamic system and only exchanges information with its neighboring nodes over a directed network. Suppose that the network communication topology contains a directed spanning tree. A sufficient condition for achieving exponential synchronization of second-order nonlinear systems in CDNs with time-varying inner coupling is derived. Detailed theoretical analysis on exponential synchronization is performed by the virtues of algebraic graph theory, distributed event-triggered transmission strategy, matrix inequality and the special Lyapunov stability analysis method. Moreover, the Zeno behavior is excluded as well by the strictly positive sampling intervals based on the upper right-hand Dini derivative. It is noted that the amount of communication among network nodes and network congestion have been significantly reduced so as to avoid the waste of network resources. Finally, a simulation example is given to show the effectiveness of the proposed exponential synchronization criteria.     

Distributed adaptive tracking control of multiple flexible spacecraft under various actuator and measurement limitations

This paper investigates the distributed leader–follower tracking problem for a team of flexible spacecraft over an undirected communication network with uncertain parameters subject to various actuator and measurement limitations. Assuming that at least one team member can receive information from the virtual leader, three scenarios are considered: (i) all the states of the flexible spacecraft can be completely measured and driven, (ii) only the rigid part of the flexible spacecraft can be driven with full state feedback and (iii) only the rigid part of the flexible spacecraft can be measured and driven. In the first case, a continuous adaptive control law is designed by building a unified architecture based on the linear-in-parameter property. In the second case, a distributed adaptive control algorithm is developed with a discontinuous parameter update law by treating the team of flexible spacecraft as two cascading subsystems. In the third case, a distributed adaptive control law is established with feedback from the generalized coordinates, generalized velocities and generalized accelerations of the rigid part of the spacecraft. It is theoretically proved that the closed-loop systems under the three designed adaptive control laws are all convergent to the target states. Finally, three numerical examples are presented to illustrate the effectiveness of the three proposed control laws.