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This paper investigates the finite-time leader-following consensus problem for multi-agent systems with switching topologies. First of all, consider the characteristic of failures, a failure distribution model which is more in line with the actual situation is established, and a semi-Markov chain is used to describe the topology switching of the multi-agent system, in which the transfer rate is time-varying. Secondly, based on the past state information, a topology-dependent consensus protocol is established, then the fault-tolerant consensus problem of leader-following multi-agent is transformed into the issue of system stability, according to the mode-dependent Lyapunov function and the finite time stochastic theorem, the sufficient conditions for the stability of the closed-loop system and the constraints of average residence time are obtained. In addition, an initial-state based $ {H_\infty } $ H ∞ performance index is proposed to reduce the influence of zero initial conditions on the system. Finally, a numerical example is provided to show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This article investigates the output fault‐tolerant consensus problem for multi‐agent systems with switching topology and deception attacks. In order to reduce the effects of switching topology, the differences between topologies can be modeled as topology uncertainties. In practice, the deception attack may occur in a random way and assumed to satisfy Bernoulli distributions. The purpose of this research is to design an output fault‐tolerant controller such that, in the presence of switching topology, actuator faults, and deception attacks, the finite‐horizon output fault‐tolerant consensus can be achieved under a prespecified H∞$$ {H}_{\infty } $$ performance. An initial‐state‐based performance requirement is constructed, and this bypasses the need for the zero initial condition in the conventional H∞$$ {H}_{\infty } $$ theory. After this, the controller gains are computed by employing an iterative linear matrix inequality scheme. Finally, a numerical example is provided to show the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

Summary: This article studies a kind of asynchronous fault‐tolerant control problem for stochastic systems (Markov jump systems, MJSs) with multiple‐types of actuator failures. Both the loss of effectiveness and stuck fault of actuator are taken into consideration in a unified actuator failures model. The asynchronization phenomenon between the controller and the original system is described by a hidden Markov model. By coupling the unknown stuck fault of actuator and the external disturbances together, the stuck fault and disturbance can be estimated simultaneously. After this, a fault‐tolerant controller based on the estimated values is designed further to automatically compensate for the faults while preserving the uniformly ultimate boundedness of the solutions. Moreover, a mode‐dependent adaptive event‐triggered mechanism is introduced to limit the number of packets sent on the network. Finally, a numerical example is employed to illustrate the effectiveness of the proposed design scheme. [ABSTRACT FROM AUTHOR]

This article focuses on the design of event-triggered asynchronous H ∞ fault-tolerant controller for Markov jump system subject to actuator faults and external disturbances. The asynchronization phenomenon not only occurs between the controlled system and controller but also exists between the controlled system and faulty actuator, which are portrayed as two corresponding hidden Markov models. Moreover, a mode-dependent event-triggered mechanism is introduced to facilitate network resources utilization. Then, by introducing mode-dependent Lyapunov-Krasovskii functional, a sufficient condition is obtained to guarantee that the closed-loop system is randomly mean square stable with H ∞ performance. Finally, two numerical examples are employed to illustrate the effectiveness of the proposed synthesis scheme. [ABSTRACT FROM AUTHOR]

In this paper, the disturbance rejection adaptive fault-tolerant constrained consensus problem of multi-agent with actuator failures is investigated. At first, an auxiliary variable based observer is designed to estimate the disturbance. Then, based on the estimated disturbance, an adaptive law is provided for partial failures. In order to avoid the zero initial condition in the traditional $H_{\infty }$ control approach, a novel performance function is constructed with the considered initial condition. After this, a disturbance rejection adaptive fault-tolerant constrained consensus algorithm is given with the performance requirement. Finally, a simulation example is provided to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper aims to design an asynchronous adaptive fault-tolerant controller for the networked stochastic unmanned surface vehicles (NSUSVs) subject to multiple types of actuator faults and external disturbance. The partial fault and bias fault of the actuator are taken into consideration simultaneously. By estimating online the unknown bias fault of the actuator and the external disturbances, the proposed adaptive fault-tolerant controller can automatically compensate for these impacts produced by actuator faults and external perturbation while preserving the uniformly ultimate boundedness of the solutions. Both the faulty actuator and the designed controller are asynchronous with the NSUSVs. Moreover, a mode-dependent adaptive event-triggered mechanism (AETM) is introduced in order to facilitate network resources utilization. Finally, the effectiveness and correctness of the proposed design scheme are verified by a numerical example. [ABSTRACT FROM AUTHOR]

This article investigates an asynchronous adaptive fault-tolerant control problem for Markov jump systems (MJSs) with actuator failures and absolutely unknown nonlinear disturbances. The hidden Markov model (HMM) is used to describe the asynchronization phenomenon between the controller and the modes of the original system. Moreover, by using the designed adaptive law, the values of actuator partial failures and the bounds of the unknown nonlinear disturbances can be estimated, respectively. Furthermore, the HMM-based asynchronous adaptive fault-tolerant controller is provided to ensure that the closed-loop system is asymptotically stable despite of unknown nonlinear disturbances. Finally, numerical examples are given to show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Summary: In this paper, mixed passive / H∞ hybrid controllers are designed for a delayed Markovian jump system with actuator constraints and alarm signal. The actuator constraints include the unknown actuator bias failure and the actuator partial failure, and the controllers are switched by using alarm signals. First, a sufficient condition for mixed passive / H∞ performance of the closed‐loop system is constructed, and robust controllers and fault‐tolerant controllers are designed, respectively. Then, mixed passive / H∞ observers are presented to ensure that the actuator bias failure is well estimated. Next, an alarm system is proposed by designing multiple thresholds to avoid false alarm, and this system is used to invoke suitable controllers and determine whether to remove the estimated value of actuator bias failure. Finally, two numerical examples are given to illustrate the effectiveness of the method. [ABSTRACT FROM AUTHOR]

This paper investigates the controller design problem for mean-square asymptotical synchronization of discrete-time neural networks with time-varying delay. We proposed the design method of synchronization controller, which considered the nonlinearity of controller input. Based on the designed controller, a delay-dependent synchronization criterion is proposed and formulated in the form of linear matrix inequalities (LMIs) by applying the Lyapunov function method. The result is extended to the delayed discrete-time neural network with uncertainty. Two numerical examples are presented to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In this study, the synchronisation problem of bilateral teleoperation systems with time‐delay and actuator faults is considered. First, the error dynamic system with actuator faults is modelled as a time‐delay system with disturbance, and a fuzzy disturbance observer (FDO) is designed to estimate the unknown non‐linear disturbance. Moreover, an FDO‐based robust controller is provided for the master robot and a reliable controller is designed for the slave robot, respectively. Next, a sufficient condition is given to ensure the tracking error; the disturbance observation error and the parameter error are uniformly ultimate bounded. Finally, a numerical example is shown to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of exponential synchronization of discrete-time neural networks with mixed time delays, actuator saturation and failures. Meanwhile, the unreliable communication links are considered between the neural networks, and such unreliable links are modeled as stochastic missing data satisfying Bernoulli distributions. In order to show the relationships between actuator constraints, unreliable communication link and mixed delay neural networks, by using Lyapunov functional approach, a missing data probability dependent exponential synchronization criterion is given. Then, based on such criterion, a reliable controller is designed to ensure that the neural networks are exponentially synchronized in the mean square. Finally, a numerical example is provided to illustrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

A new stochastic switched linear model is established to describe the Zigbee-based wireless networked control system (WNCS) with both network-induced delay and packet dropout. The network-induced delay can be less or longer than one sampling period. A sufficient condition is presented for the exponentially mean square stability of the closed-loop WNCS, and corresponding state feedback controller is designed by using the augmenting technique and multi-Lyapunov approach. Then, combined with carrier sense multiple access with collision avoidance (CSMA-CA) algorithm, a method is given to choose proper parameter values. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The problem of robust stabilisation for uncertain discrete singular systems with time-varying delay is discussed in this article. First, a new delay-distribution-dependent Lyapunov function is established. Then, sufficient conditions are proposed for guaranteeing that the uncertain discrete singular system with time-varying delay has the properties of regularity, causality and stability. Finally, a suitable robust state feedback controller is designed by linear matrix inequality. Numerical examples illustrate that the results derived from the proposed method are less conservative than the existing ones. [ABSTRACT FROM AUTHOR]

The problem of chattering free sliding mode control for a class of uncertain discrete singular systems with state delay is investigated in this paper. As a component of the solution, a new least squares support vector machine ( LS- SVM) reaching law is proposed. In terms of linear matrix inequalities, a delay-dependent condition for sliding mode dynamics to be regular, causal, and asymptotically stable is established, and the chattering problem that appears in traditional variable structure systems is eliminated. Numerical examples are provided to demonstrate the applicability of the proposed methods. [ABSTRACT FROM AUTHOR]

The objective of this paper is to further improve the method of treating hemangioma with the copper needle and to standardize this method. The CHT-5302/MP copper needle therapeutic instrument has been used in a number of assorted cases. A review of 180 hemangioma cases treated by this instrument verifies that it can offer sufficient electricity for clinical use. This shows that the new treatment method offers a reliable, effective means for the treatment of high- or low-flow vascular malformations and hemangiomas. As there are no complications, it is better than previous treatments for hemangioma. It can offer an effective therapy for patients who previously could not be treated or who might require excision of limbs. [ABSTRACT FROM AUTHOR]

This paper is concerned with the stability analysis problem for uncertain stochastic discrete-time recurrent neural networks with time-varying delay. By using linear matrix inequality method and discrete Jensen inequality, a new Lyapunov–Krasovskii function is established to derive sufficient condition for globally asymptotical stability in mean square of the recurrent neural networks with stochastic disturbance. As an extension, we further consider the stability analysis problem for the same class of neural networks but with uncertainty. It is shown that the newly obtained result is less conservative than the existing ones when the described system is without disturbance and uncertainty. Meanwhile, the computational complexity is reduced since less variable is involved. Two numerical examples are presented to illustrate the effectiveness and the benefits of the proposed method. [ABSTRACT FROM AUTHOR]