In this paper, we address the mixed *H*_{2}/*H*_{∞} synchronization control for the coupled partial differential systems. First, we introduce the synchronization error dynamics and transform the problem of mixed *H*_{2}/*H*_{∞} synchronization control of coupled partial differential systems into the problem of mixed *H*_{2}/*H*_{∞} stabilization of the synchronization error dynamics. Then, both the finite and infinite horizon cases for the mixed *H*_{2}/*H*_{∞} synchronization control are considered. Sufficient conditions guaranteeing the existence of the solutions to the mixed *H*_{2}/*H*_{∞} synchronization control problem are given via a standard completing square technique. When the states of the synchronization error systems are unavailable, the Lunberger observer is designed, and the observer-based mixed *H*_{2}/*H*_{∞} synchronization problem is investigated. Based on the solutions to the coupled differential Riccati equations, the optimal control for the observer-based mixed *H*_{2}/*H*_{∞} synchronization control is presented. One more time, both the finite and infinite horizon cases are studied under the observer situation. Copyright © 2016 John Wiley & Sons, Ltd.

This paper deals with the leader-following consensus of discrete-time multi-agent systems subject to both position and rate saturation. Each agent is described by a discrete-time general linear dynamic with actuator subject to position and rate saturation. A modified algebraic Riccati equation and low-gain feedback design technique are used to construct both state feedback and output feedback control protocols. It is established that a semi-global leader-following consensus can be achieved when the system is asymptotically null controllable with bounded controls and a leader agent has a directed path to every follower agent. Finally, several simulations are carried out to illustrate the results. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, we consider the problem of leader synchronization in systems with interacting agents in large networks while simultaneously satisfying energy-related user-defined distributed optimization criteria. But modeling in large networks is very difficult, and for that reason, we derive a model-free formulation that is based on a separate distributed Q-learning function for every agent. Every Q-function is a parametrization of each agent's control, of the neighborhood controls, and of the neighborhood tracking error. It is also evident that none of the agents has any information on where the leader is connected to and from where she spreads the desired information. The proposed algorithm uses an integral reinforcement learning approach with a separate distributed actor/critic network for each agent: a critic approximator to approximate each value function and an actor approximator to approximate each optimal control law. The derived tuning laws for each actor and critic approximators are designed appropriately by using gradient descent laws. We provide rigorous stability and convergence proofs to show that the closed-loop system has an asymptotically stable equilibrium point and that the control policies form a graphical Nash equilibrium. We demonstrate the effectiveness of the proposed method on a network consisting of 10 agents. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, a new second-order sliding mode output feedback control law is proposed. It amounts to approach the dynamic performance of the twisting algorithm, but the main advantage of this new control method is that it requires only the information of the sliding variable, and not its derivative. A gain adaptation law is also developed for this new control law. Then this control strategy is applied to the position control of an electropneumatic system, and its performance is compared with other two very recent adaptive second-order sliding mode control laws. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, the multi-tasking optimal control problem is addressed in the delta-domain for a class of networked control systems (NCSs) with external disturbances. A delta-domain model is proposed to describe the NCSs with random packet dropouts and long-time delay, and the so-called *ε*-Nash equilibrium is employed to quantify the impacts from the disturbances on the underlying NCSs. The multi-tasking optimal control strategies are developed and the upper bound for the *ε*-Nash equilibrium is provided explicitly. Some simulation results on the two-area load frequency control system are given to show the validity and applicability of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, we investigate the mean square exponential synchronization of stochastic nonlinear complex dynamical networks with or without communication delays. A new self-triggered mechanism is proposed to reduce the amount of communication while preserving the desired system's performance. Under this mechanism, the next sampling instant is dynamically determined by the latest transmitted state rather than the online detection of the event-triggered condition. Meanwhile, we show that the inter-execution time of self-triggered mechanism is bounded by a strictly positive constant, and the maximal allowable delay of the underlying system is given. A simulation is provided to illustrate the effectiveness of the proposed self-triggered scenario. Copyright © 2016 John Wiley & Sons, Ltd.

The paper presents a feedback control design that allows a Dubins vehicle to enter a circular trajectory using only range-based measurements from the vehicle to the center of the trajectory. The controller is derived and analyzed based on a novel state space kinematic model, with the state that is composed of two continuous and one discrete state variables.The evolution of the discrete state variable is not completely defined by the model and the control design has to deal with the ambiguity of this value. Based on the conditions that need to be satisfied for the controller to work, the closed loop dynamics analysis can be performed based on 2D phase portraits, and it can be shown that the controller can work in the case of the bounded turning rate of the vehicle. The conditions define only bounds for the controller parameters and not their specific values. Therefore, the parameters can be selected based on the maximal working range of the controller and linear quadratic regulator design. The proposed control design is illustrated by 2D phase portraits and simulations describing the control implementation, which is based only on range measurements. Copyright © 2016 John Wiley & Sons, Ltd.

This paper is focused on designing a distributed adaptive control scheme for a vehicular platoon with unknown bounded velocity/acceleration disturbances and unknown nonlinear dead-zone inputs. Our aim is to design distributed adaptive controllers based on integral sliding mode control techniques that guarantee practical exponential convergence (i.e., exponential stability of an arbitrarily small neighborhood of zero) of the spacing errors and the string stability of the whole vehicular platoon. The contributions of this paper are that: (i) based on a modified constant time headway policy, the whole vehicular platoon is guaranteed to have string stability despite dead zone inputs; (ii) adaptive compensation terms are constructed to compensate for the time-variant effects caused by unknown bounded velocity/acceleration disturbances, and unknown dead zone inputs; (iii) an efficient numerical method for avoiding the singularity problem of the control law is also proposed. Numerical simulation results show the validity and advantages of the proposed method are significantly higher traffic density and string stability. Copyright © 2016 John Wiley & Sons, Ltd.

Stabilization control is an essential mission for the tethered space robot-target combination during the postcapture phase of tethered space robot (TSR). In this paper, the stabilization problem of such a tumbling combination is studied. With the consideration of the space tether and the attitude of the TSR's gripper, the dynamic model of the combination is first derived using Lagrange method. Then a robust nonlinear controller for the combination is proposed based on the backstepping control method. Considering the constraint on the velocity of the space tether, command filter method is utilized to guarantee the velocity of the space tether within a permitted range. A feedback term is designed to compensate the saturation of the thruster. Moreover, an adaptive law is designed to estimate the disturbance of parameter uncertainties and this disturbance is compensated in the proposed controller. Numerical simulations suggest that the proposed robust controller can realize the orbit and attitude stabilization of the combination; besides, the velocity of the space tether is effectively constrained and the parameter uncertainties of the combination can be compensated via the adaptive law. Copyright © 2016 John Wiley & Sons, Ltd.

This study presents a feedback control strategy for the regulation of a planar vertical takeoff and landing aircraft. To this end, two controllers that work simultaneously were designed. The first controller is devoted to stabilizing the vertical variable and is based on a simple feedback-linearization procedure in combination with a saturation function. The second controller – based on a combination of the traditionally PD-controller and a sliding mode controller – stabilizes both the horizontal and angular variables to the desired rest position. The performance of the closed-loop system is demonstrated through simulation results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper considers the distributed event-triggered consensus problem for multi-agent systems with general linear dynamics under undirected graphs. Based on state feedback, we propose a novel distributed event-triggered consensus controller with state-dependent threshold for each agent to achieve consensus, without continuous communication in either controller update or triggering condition monitoring. Each agent only needs to monitor its own state continuously to determine if the event is triggered. It is proved that there is no Zeno behavior under the proposed consensus control algorithm. To relax the requirement of the state measurement of each agent, we further propose a novel distributed observer-based event-triggered consensus controller to solve the consensus problem in the case with output feedback and prove that there is no Zeno behavior exhibited. Finally, simulation results are given to illustrate the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper aims to introduce a new approach to optimize the tunable controller parameters of linear parameterizable controllers. The presented approach is frequency-domain based and can therefore directly be used to tune, among others, proportional integral derivative controllers, low/high-pass filters, and notch filters, using a Frequency Response Function of the plant. The approach taken in this paper is to extract the tunable controller parameters into a diagonal matrix gain and absorb the remainder of the controller in the plant. Then, the generalized Nyquist stability criterion is exploited so as to impose stability and performance specifications on the closed-loop system. It is shown that the approach results in a convex feasibility problem for certain controller cases and can be reformulated such that it can also be used for grey-box system identification. Simulation and experimental examples demonstrate the efficacy of the approach. © 2016 The Authors. International Journal of Robust and Nonlinear Control published by John Wiley & Sons, Ltd.

Hysteretic characteristics commonly exist in piezoelectric actuators (PEAs) and degrade the positioning accuracy particularly in the case of low-frequency trajectory tracking. A PEA with hysteretic characteristics is usually difficult to precisely control because the unmeasurable hysteretic force is typically generated by a complicated nonlinear dynamic model. This task can be theoretically formulated as a robust output regulation problem with a specific nonlinear and non-autonomous exosystem. In this paper, the theoretical problem is first solved within a novel internal model architecture. With the proposed controller, the PEA is able to asymptotically track a desired reference trajectory with the robustness to plant uncertainties. The effectiveness of the design is verified by extensive experiments. Copyright © 2016 John Wiley & Sons, Ltd.

This paper proposes a distributed model-independent algorithm to achieve leaderless consensus on a directed network where each fully-actuated agent has self-dynamics described by Euler–Lagrange equations of motion. Specifically, we aim to achieve consensus of the generalised coordinates with zero generalised velocity. We show that on a strongly connected graph, a model-independent algorithm can achieve the consensus objective at an exponential rate if an upper bound on the initial conditions is known a priori. By model-independent, we mean that each agent can execute the algorithm with no knowledge of the equations describing the self-dynamics of any agent. For design of the control laws which achieve consensus, a control gain scalar and a control gain matrix are required to satisfy several inequalities involving bounds on the matrices of the agent dynamic model, bounds on the Laplacian matrix describing the network topology and the set of initial conditions; design of the algorithm therefore requires some knowledge on the bounds of the agent dynamical parameters. Because only bounds are required, the proposed algorithm offers robustness to uncertainty in the parameters of the multiagent system. We systematically show that additional relative velocity information improves the performance of the controller. Numerical simulations are provided to show the effectiveness of the algorithm. Copyright © 2016 John Wiley & Sons, Ltd.

This paper considers the stabilization problem for a class of discrete-time delayed systems by exploiting a partially delay-dependent controller whose gains suffer a disordering phenomenon simultaneously. Two stochastic variables are used to describe the partially delay-dependent and disordering properties, which are not independent, and referred to the original operation modes here. By introducing an augmented Markov chain, the corresponding closed-loop system is transformed into a Markovian jump system with four new operation modes (NOMs). Based on the proposed model, a kind of controller depending on NOMs is firstly proposed with linear matrix inequalities forms. Moreover, without designing a controller containing NOMs directly, another kind of stabilizing controller referring to one depending on original operation modes is developed, which is composed of a series of NOM-dependent controllers and satisfies a minimum variance approximation. Finally, two numerical examples are used to demonstrate the utility and superiority of the proposed methods. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, we apply the active disturbance rejection control approach to output-feedback stabilization for uncertain lower triangular nonlinear systems with stochastic inverse dynamics and stochastic disturbance. We first design an extended state observer (ESO) to estimate both unmeasured states and stochastic total disturbance that includes unknown system dynamics, unknown stochastic inverse dynamics, external stochastic disturbance, and uncertainty caused by the deviation of control parameter from its nominal value. The stochastic total disturbance is then compensated in the feedback loop. The constant gain and the time-varying gain are used in ESO design separately. The mean square practical stability for the closed-loop system with constant gain ESO and the mean square asymptotic stability with time-varying gain ESO are developed, respectively. Some numerical simulations are presented to demonstrate the effectiveness of the proposed output-feedback control scheme. Copyright © 2016 John Wiley & Sons, Ltd.

This paper presents an approach to simultaneously estimating the states and inputs of discrete-time linear switched singular state-delayed systems with unknown inputs, multiple missing measurements, and average dwell time (ADT) switching. In each output measurement channel of the system, the data loss incident is controlled by an individual stochastic variable obeying a certain probability distribution on the interval [01]. The proposed approach is based on the design of a switched, loss-probability-dependent proportional integral observer under the *ℓ*_{2} input attenuation framework. By using piecewise Lyapunov function technique, ADT scheme, stochastic analysis, and projection lemma, sufficient conditions for the existence of such an observer are established in terms of linear matrix inequalities, which guarantee that the resulting estimation error system is stochastically exponentially admissible and achieves an (non-weighted) *ℓ*_{2} gain from the augmented unknown input to the state and unknown input estimation errors under ADT switching. Moreover, a method is provided to seek the minimum allowable *ℓ*_{2} gain level for a desired ADT of the switching signals. The effectiveness of the proposed approach is illustrated by a simulation example of direct current (DC) servomechanism control system. Copyright © 2016 John Wiley & Sons, Ltd.

This paper investigates the problem of exponential stability and *l*_{1}-gain performance analysis for a class of discrete-time switched positive singular systems with time-varying delay. Firstly, a necessary and sufficient condition of positivity for the system is established by using the singular value decomposition method. Then by constructing an appropriate co-positive Lyapunov functional and using the average dwell time scheme, we develop a sufficient delay-dependent condition and identify a class of switching signals for the switched positive singular system to be exponentially stable and meet a prescribed *l*_{1}-gain performance level under the switching signal. Based on this condition, the decay rate of the system can be tuned and the optimal system performance level can be determined by solving a convex optimization problem. All of the criteria obtained in this paper are presented in terms of linear programming, which suggests a good scalability and applicability to high dimensional systems. Finally, a numerical example is presented to demonstrate the effectiveness of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, we develop nonlinear distributed or semi-decentralized cooperative control schemes for a team of heterogeneous autonomous underwater vehicles (AUVs). The objective is to have the network of AUVs follow a desired trajectory, while the agents maintain a desired formation when there is a virtual leader whose position information is only available and known to a very small subset of the agents. The virtual leader does not receive any feedback and information from the other agents and the agents only communicate with their nearest neighboring agents. It is assumed that the model parameters associated with each vehicle/agent is different, although the order of the agents is the same. The developed and proposed nonlinear distributed cooperative control schemes are based on the dynamic surface control methodology for a network of heterogeneous autonomous vehicles with uncertainties. The development and investigation of the dynamic surface control methodology for a team of cooperative heterogenous multi-agent nonlinear systems is accomplished for the first time in the literature. Simulation results corresponding to a team of six AUVs are provided to demonstrate and illustrate the advantages and superiority of our proposed cooperative control strategies as compared to the methods that are available in the literature. Copyright © 2016 John Wiley & Sons, Ltd.

This paper investigates the fault detection (FD) problem for a class of nonlinear uncertain systems in strict feedback form with an output constraint. The key idea is to design an observer to generate the FD signals and the output estimate, which also satisfies the output constraint. To facilitate constraint handling, the constraints on the output and the output estimate are transformed into the output estimation error constraint. Then, the FD observer is designed in a recursive framework. By employing a barrier Lyapunov function, the output estimation error constraint is incorporated in the last step of the recursive observer design algorithm to prevent constraint violation. It is shown that the output estimation error is uniformly bounded and satisfies the constraint for the fault-free case. Furthermore, the residual signal is constructed by the output estimation error, and its corresponding bound is used as threshold. Compared with the FD method without considering the constraints, the proposed FD scheme provides a smaller threshold and characterizes a larger set of faults, which can be detected. Finally, simulation results are presented to illustrate the benefits of the proposed FD scheme. Copyright © 2016 John Wiley & Sons, Ltd.

The purpose of fault diagnosis of stochastic distribution control systems is to use the measured input and the system output probability density function to obtain the fault estimation information. A fault diagnosis and sliding mode fault-tolerant control algorithms are proposed for non-Gaussian uncertain stochastic distribution control systems with probability density function approximation error. The unknown input caused by model uncertainty can be considered as an exogenous disturbance, and the augmented observation error dynamic system is constructed using the thought of unknown input observer. Stability analysis is performed for the observation error dynamic system, and the *H*_{∞} performance is guaranteed. Based on the information of fault estimation and the desired output probability density function, the sliding mode fault-tolerant controller is designed to make the post-fault output probability density function still track the desired distribution. This method avoids the difficulties of design of fault diagnosis observer caused by the uncertain input, and fault diagnosis and fault-tolerant control are integrated. Two different illustrated examples are given to demonstrate the effectiveness of the proposed algorithm. Copyright © 2016 John Wiley & Sons, Ltd.

The problem of robust global consensus tracking of linear multiagent systems with input saturation and input-additive uncertainties is investigated in this paper. By using the parametric Lyapunov equation approach and an existing dynamic gain scheduling technique, a new distributed nonlinear-gain scheduling consensus-trackining algorithm is developed to solve this problem. Under the assumption that each agent is asymptotically null controllable with bounded control, it is shown that the robust global consensus tracking can be achieved under the undirected graph provided that its generated graph contains a directed spanning tree. Compared with the existing algebraic Riccati equation approach, which requires the online solution of a parameterized algebraic Riccati equation, all the parameters in the proposed nonlinear algorithm are offline determined *a priori*. Finally, numerical examples are provided to validate the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper studies coordinated control of multiple Lagrangian systems with parametric uncertainties subject to external disturbances by proposing a fully distributed continuous control law based on the improved self-tuning adaptive observer inspired by non-identifier-based high-gain adaptive control technique. Under this distributed continuous control law, a group of Lagrangian systems are driven to the convex hull spanned by multiple heterogenous dynamic leaders, which can be any combination of step signals of arbitrary unknown magnitudes, ramp signals of arbitrary unknown slopes, and sinusoidal signals of arbitrary unknown amplitudes, initial phases, and any unknown frequencies. It is also worth to mention that this control law we propose, depending neither on any information of leader systems for uninformed followers, nor on external disturbances, even independent of neighbors' velocity, can achieve asymptotic tracking of multiple leaders without any additional condition instead of ensuring the ultimate boundedness of the containment error as in the literature. Copyright © 2016 John Wiley & Sons, Ltd.

The problem of global adaptive state regulation is investigated via output feedback for uncertain feedforward nonlinear time-delay systems. Compared with existing results, our control schemes can be applicable to more general nonlinear time-delay systems because of combining the low-gain scaling approach with the backstepping method. In particular, we allow that there exist uncertain output function and uncertain growth rate imposed on nonlinear terms. Also, one considers a class of nonlinear systems with main-axis delay. By the Lyapunov–Krasovskii theorem, delay-independent controllers are proposed by constructing novel low-gain observers driven by system input, to regulate the states of original system while all the closed-loop signals are globally bounded. Furthermore, two examples are given to illustrate the usefulness of our results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper describes a nonlinear programming-based robust design methodology for controllers and prefilters of a predefined structure for the linear time-invariant systems involved in the quantitative feedback theory. This controller and prefilter synthesis problem is formulated as a single optimization problem with a given performance optimization objective and constraints enforcing stability and various specifications usually enforced in the quantitative feedback theory. The focus is set on providing constraints expression that can be used in standard nonlinear programming solvers. The nonlinear solver then computes in a single-step controller and prefilter design parameters that satisfy the prescribed constraints and maximizes the performance optimization objective. The effectiveness of the proposed approach is demonstrated through a variety of difficult design cases like resonant plants, open-loop unstable plants, and plants with variation in the time delay. Copyright © 2016 John Wiley & Sons, Ltd.

This paper considers semi-global output feedback control for more general nonlinear systems with unknown time-delay and output function whose derivative is unbounded from above. By introducing a new observer and using the backstepping design method and the Razumikhin stability theorem, an output feedback controller is constructed to achieve a semi-global stability. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, a novel consensus protocol for second-order multi-agent systems is elegantly designed, and it relaxes the common requirement of the velocity information of the agents. An interesting consensus criterion is explicitly derived in terms of the proposed cooperation law provided that the dynamical equation for each agent is linear. As an extension, the proposed cooperation rule is further extended to a general scenario, where the coupling weights characterizing the relationships among the neighboring agents are time-varying. Accordingly, two distributed cooperative algorithms (node/edge-based scheme) are explicitly designed. Moreover, we study the case of network with switching communication setting. It shows that edge-based law is capable with the time-varying topology, while the node-based scheme is not. In addition, the proposed coordination strategies are applied to the tracking problem as well. Finally, these obtained consensus results are well supported in the light of the pendulum models. Copyright © 2016 John Wiley & Sons, Ltd.

In this article, an observer for linear time variant systems affected by unknown inputs is suggested. The proposed observer combines the deterministic least squares filter and the high-order sliding-mode differentiator to provide exact state reconstruction in spite of bounded unknown inputs and system instability. The cascade structure of the algorithm provides a correct state reconstruction for the class of linear time variant systems that satisfy the structural property of strong observability. Simulations illustrate the performance of the proposed algorithm. Copyright © 2016 John Wiley & Sons, Ltd.

This paper is devoted to saturated control of switched delay systems. The main focus is to find a suitable switching law and saturated output feedback controllers such that the closed-loop systems are asymptotically stable and have the disturbance tolerance/rejection capacity. A mixed slow/arbitrary switching approach, so-called persistent dwell time (PDT) switching, is used to design the switching law. Compared with the slow switching, it is more general and leads to more flexibility in the process of constructing switching signals. More importantly, the proposed PDT is dependent on state delay, which includes the previous delay-independent PDT. Next, time-varying ellipsoids and a prescribe *l*_{2}-gain are introduced to characterize the disturbance tolerance and rejection capacities of systems, respectively. Based on the proposed results, the relation between delay-dependent PDT and level of disturbance tolerance/rejection is shown. Finally, saturated controllers working in time-varying hull controllable regions are designed. Thus, the considered problem is solved. An example is exploited to illustrate the effectiveness of the proposed results. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, a new event-switched control method is presented for controlling discrete-time linear systems subject to bounded disturbances. The main advantage of the proposed method is that the nominal performance of the controlled system with periodic control updates is kept in a framework that do not require to periodically update the control law. The feedback control loop can be opened as long a state-dependent event condition is satisfied. This condition is obtained using set theory approaches. In particular, the concept of robustly positively invariant sets is used to calculate the nominal performance and the event condition. The simulation presented in this paper confirms the efficiency of the present approach. A reduction of the numerical complexity of the approach is also proposed. Copyright © 2016 John Wiley & Sons, Ltd.

We consider security issues for consensus-based distributed estimation problem. In a sensor network, an attacker with limited power injects random false data into the communication links so as to degrade the network performance. First, an optimal estimator is designed by minimizing the mean-squared estimation error of each sensor under hostile attacks. Then, a sufficient condition is provided to guarantee the stability of the proposed estimator. Finally, a set of suboptimal attacking sequences is obtained for the attacker to maximize the network estimation error. Illustrative examples are provided to verify the effectiveness of the suboptimal attacking strategy. Copyright © 2016 John Wiley & Sons, Ltd.

This paper presents feedback sensitivity functions analysis of implicit Lyapunov function-based control system in case of finite-time stabilization problem. The Gang of Four is chosen as a feedback sensitivity tool. The results can be used for parametric tuning of control algorithms in order to guarantee desired closed-loop sensitivity specifications. The obtained results are supported by numerical examples. Copyright © 2016 John Wiley & Sons, Ltd.

This paper addresses a fault detection strategy in finite frequency domain for networked system with communication constraints and packet loss. The considered communication constraint is that only one data packet can gain into the networks at each time-slot, and the fault detection filters complete the task with only partially available measurements. With consideration of the data packet loss and the stochastic scheduling protocol, a nonhomogeneous Markov jump system is firstly derived to describe the networked systems. For this class of systems, the generalized Kalman–Yakubovic–Popov lemma-based finite frequency fault detection filter design methods are invalid. To tackle this problem, a new mode-dependent lemma is developed to capture the system performance in finite frequency domain. Further, a set of fault detection filters are designed corresponding to the accessed nodes accordingly. Finally, an example is given to show the effectiveness of the proposed fault detection approach. Copyright © 2016 John Wiley & Sons, Ltd.

We propose a control strategy based on distributed adaptive leader-follower consensus algorithms for multi-agent systems (MAS) affected by switching network events. The strategy allows each agent in the MAS to compute its own control input based on local information and information coming from its neighbors. In this sense, MAS distributed control laws are obtained where the coupling gain of the associated communication graph is adapted dynamically in real-time. The consensus algorithm is extended with a switching network topology approach, which ensures appropriate performance even when the MAS network topology is prone to arbitrary switching. A real-time experimental application is presented, where a MAS consisting of four rotorcraft UAS successfully performed the tasks of autonomously approaching and escorting a leader, even in the situation when the network topology was arbitrarily changing. Additionally, a Lyapunov stability analysis is included, which demonstrates that the tracking errors between leader and follower agents converge asymptotically to zero. Copyright © 2016 John Wiley & Sons, Ltd.

This paper studies distributed filtering-based ssynchronization of diffusively state-coupled heterogeneous systems. For given heterogeneous subsystems and a network topology, sufficient conditions for the filtering-based synchronization are developed with a guaranteed performance. The estimation and synchronization error dynamics are obtained in a decoupled form, and it is shown that the filter and the controller can be designed separately by LMIs. The feasibility of the proposed design method using LMIs is discussed, and the main results are validated through examples with various setup. Copyright © 2016 John Wiley & Sons, Ltd.

The analysis of some properties for the equilibria of switched dynamic systems is addressed. In particular, the geometric properties of the equilibrium region in state space and the algebraic properties of the equations defining it are studied. Based on fundamental results from algebraic geometry, the equilibria properties of switched dynamic systems are analyzed. This alternative approach allows to obtain information about the set of equilibrium points without explicitly computing it. This study is developed for three different formulations of switched dynamic systems, revealing some interesting algebraic and geometric relations in their corresponding equilibria. Some examples, including the case of a power converter, are presented for illustration purposes. Copyright © 2016 John Wiley & Sons, Ltd.

The generator design for causal ideal internal dynamics (IID), namely, solving IID, is a fundamental problem in a nonminimum-phase output tracking process. In this paper, for a class of unstable matrix differential equations, a new causal IID generator is proposed, whose parameters are partly chosen via optimization. Compared with existing similar design schemes, it is applicable to matrix differential equations with singular system matrices. Also, it requires less computation, avoids taking higher order derivatives, and can be easily extended to treat slowly time-varying matrix differential equations without the need for extra computation. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, the problem of composite anti-disturbance resilient control is studied for Markovian jump nonlinear systems with partly unknown transition probabilities and multiple disturbances. The multiple disturbances include two types: one is in the input channel generated by an exogenous system with perturbations, and the other is belong to *L*_{2}[0,*∞*). The first class of disturbances is estimated by designing a disturbance observer. Combining the disturbance estimation with conventional *L*_{2} − *L*_{∞} resilient control law, a composite anti-disturbance control scheme is constructed such that the closed-loop system is stochastically stable, and different types of disturbances can be attenuated and rejected. By using Lyapunov function method and linear matrix inequalities technique, some sufficient conditions for the desired controller and observer gains are developed. Finally, an application example is provided to demonstrate the effectiveness of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.

This paper is concerned with the design and the synthesis of the impulsive positive observer (IPO) for positive linear continuous systems. The IPO can estimate the states for positive systems even when the measured output is only available at discrete-time instants. In this paper, a time-varying weighted copositive Lyapunov function is constructed, and the upper and lower bounds of impulsive intervals method combined with the convex combination technique are used to establish sufficient conditions for the existence of the IPO. Furthermore, the design of the dynamic output feedback controller based on the IPO is addressed to positively stabilize positive linear systems. Algorithms are given to design the IPO and the controller, respectively. Finally, two numerical examples are provided to show the effectiveness of the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd.

A robust consensus controller is proposed for heterogeneous higher-order nonlinear multi-agent systems, when the agent dynamics are involved with mismatched uncertainties. A distributed consensus protocol based on a time-varying nonhomogeneous finite-time disturbance observer and sliding mode control is designed to realize the network consensus of higher-order multi-agent systems. The time-varying finite-time disturbance observer overcomes the problem of peaking value near the initial time caused by the constant gain one and is designed to estimate the uncertainties and to mitigate the effect of mismatched uncertainties during the sliding mode. To eliminate the chattering phenomenon and ensure finite-time convergence to the sliding surface, the control law is designed by using the super twisting algorithm. Finally numerical simulations are given to illustrate the validity of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.

Modern chemical plants are becoming very complex, often consisting of a number of nonlinear process units (subsystems) with strong interactions due to material recycle and energy integration. The operation setpoint may need to be adjusted from time to time based on the market demand. To address the aforementioned challenges, a plantwide distributed nonlinear control scheme based on differential dissipativity is proposed in this paper, which can ensure plantwide incremental exponential stability and achieve bounded incremental *L*_{2} gain performance. As a non-unique property, the differential dissipativity of individual subsystem is shaped by a setpoint-independent control structure – differential state feedback control. The dissipativity properties of subsystems and individual controllers are determined simultaneously as a large-scale feasibility problem to ensure the plantwide stability and performance. It is converted into an LMI condition for plantwide supply rate planning and small-scale sum-of-squares programming problems for individual subsystem dissipativity shaping, by using the alternating direction method of multipliers method. The proposed approach is illustrated using a chemical reactor network with a recycle stream. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, a finite horizon *H*^{∞} control problem is solved for a class of linear quantum systems using a dynamic game approach for the case of sampled-data measurements. The methodology adopted involves an equivalence between the quantum problem and two auxiliary classical problems. Copyright © 2016 John Wiley & Sons, Ltd.

This paper presents a systematic approach to the design of a nonlinear robust dynamic state feedback controller for nonlinear uncertain systems using copies of the plant nonlinearities. The technique is based on the use of integral quadratic constraints and minimax linear quadratic regulator control, and uses a structured uncertainty representation. The approach combines a linear state feedback guaranteed cost controller and copies of the plant nonlinearities to form a robust nonlinear controller with a novel control architecture. A nonlinear state feedback controller is designed for a synchronous machine using the proposed method. The design provides improved stability and transient response in the presence of uncertainty and nonlinearity in the system and also provides a guaranteed bound on the cost function. An automatic voltage regulator to track reference terminal voltage is also provided by a state feedback equivalent robust nonlinear proportional integral controller. Copyright © 2016 John Wiley & Sons, Ltd.

This paper addresses the bounded *H*_{∞} synchronization problem for the time-varying coupled networks with stochastic noises and randomly occurring nonlinearities over a finite horizon. The bounded *H*_{∞} synchronization performance constraint is proposed to quantify the degree of the synchronization regarding the exogenous disturbances. The nonlinearities considered in this paper are assumed to satisfy the sector-like conditions and characterized by a time-varying Bernoulli distribution with measurable probability in real time. Based on the Kronecker product and the Hadamard product, a sufficient condition is established firstly to ensure the bounded *H*_{∞} synchronization of the network by utilizing the probability-dependent method. Then the obtained criterion is further converted into a computationally available one by transforming the time-varying probability into a polytopic form, which is presented in terms of matrix inequalities and hence can be verified easily by applying the Matlab toolbox. Finally, simulation examples are given to demonstrate the effectiveness of the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper addresses the problem of designing controllers that are robust to large changes in the undamped natural frequencies of a plant. Plants must be represented by means of minimum phase rational transfer functions of an arbitrary order whose oscillatory dynamics must fulfill the pole-zero interlacing property on the imaginary axis. The design specifications are as follows: (i) a phase margin for the nominal plant; (ii) a gain crossover frequency for the nominal plant; and (iii) a constant phase margin for large variations in the undamped natural frequencies of the plant, the zeros associated with the oscillatory part of the plant and the gain of the plant. Theorems are proposed that define the structure of the controllers that fulfill these specifications. We show that these robust controllers must necessarily include a fractional-order integro-differential term. Analytical simple expressions with which to obtain the simplest controllers that verify the aforementioned specifications are also obtained. Some relevant features of these fractional-order controllers are later highlighted. Finally, as an example, these controllers are applied to a Buck electronic converter. Copyright © 2016 John Wiley & Sons, Ltd.

This paper focuses on the adaptive stabilization problem for a class of high-order nonlinear systems with time-varying uncertainties and unknown time-delays. Time-varying uncertain parameters are compensated by combining a function gain with traditional adaptive technique, and unknown multiple time-delays are manipulated by the delicate choice of an appropriate Lyapunov function. With the help of homogeneous domination idea and recursive design, a continuous adaptive state-feedback controller is designed to guarantee that resulting closed-loop systems are globally uniformly stable and original system states converge to zero. The effectiveness of the proposed control scheme is illustrated by the stabilization of delayed neural network systems. Copyright © 2016 John Wiley & Sons, Ltd.

This paper addresses the problems of disturbance estimation and anti-disturbance control for nonlinear system with exogenous disturbance, which is generated from an unknown exogenous system. The state observer and the adaptive disturbance observer are designed, simultaneously. Compared with the existing methods, which assumed that the exogenous system parameter matrix was known, our disturbance observer is more applicable in practice. Utilizing the estimation information, an observer-based dynamic output feedback controller is designed, which avoids the influence of output disturbance on the closed-loop system, and contains a disturbance compensation term to compensate the input disturbance. Finally, simulations are provided to demonstrate the effectiveness of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd.

This paper is concerned with application of expectation maximization (EM) algorithm for deriving an adaptive version of divided difference filter for joint state estimation and multiplicative parameter identification of nonlinear system with the colored measurement noise. Owing to the fact that there exist a mutual coupling and interaction of state and parameter on each other, it requires a joint or simultaneous estimation of both state and parameter by a mutual iteration, and justly, EM iterates Expectation (E-)step and Maximization (M-)step to meet such requirement. Firstly, E-step involves state filtering and smoothing issues under knowing the previous parameter identification results, which is well solved by resorting to the Gaussian approximation with a trade-off between accuracy and complexity. Further, such Gaussian approximation estimators are applied for evaluating the condition expectation of complete-data likelihood function, nonlinearly characterized by the multiplicative parameter needed to be optimized. Secondly, M-step deals with the maximization of the condition expectation by directly making its derivative as zero to obtain the current general parameter identification equation as the nonlinear integral. Thirdly, by iteratively operating E-step and M-step, an adaptive divided difference filter is proposed for joint state estimation and parameter identification by using the second-order Stirling interpolation to compute the associated nonlinear integral. Finally, the robust performance of the EM-based adaptive version of divided difference filter to the unknown or time-varying multiplicative parameter, as compared with the standard augmentation method, is demonstrated by a maneuvering target tracking example. Copyright © 2016 John Wiley & Sons, Ltd.

This paper aims to investigate the problem of *H*_{∞} output tracking control for a class of switched linear parameter-varying (LPV) systems. A sufficient condition ensuring the *H*_{∞} output tracking performance for a switched LPV system is firstly presented in the format of linear matrix inequalities. Then, a set of parameter and mode-dependent switching signals are designed, and a family of switched LPV controllers are developed via multiple parameter-dependent Lyapunov functions to enhance control design flexibility. Even though the *H*_{∞} output tracking control problem for each subsystem might be unsolvable, the problem for switched LPV systems is still solved by the designed controllers and the designed switching law. Finally, the effectiveness of the proposed control design scheme is illustrated by its application to an *H*_{∞} speed adjustment problem of an aero-engine. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, we study the input quantization problem for a class of uncertain nonlinear systems. The quantizer adopted belongs to a class of sector-bounded quantizers, which basically include all the currently available static quantizers. Different from the existing results, the quantized input signal, rather than the input signal itself, is used to design the state observers, which guarantees that the state estimation errors will eventually converge to zero. Because the resulting system may be discontinuous and non-smooth, the existence of the solution in the classical sense is not guaranteed. To cope with this problem, we utilize the non-smooth analysis techniques and consider the Filippov solutions. A robust way based on the sector bound property of the quantizers is used to handle the quantization errors such that certain restrictive conditions in the existing results are removed and the problem of output feedback control with input signal quantized by logarithmic (or hysteresis) quantizers is solved for the first time. The designed controller guarantees that all the closed-loop signals are globally bounded and the tracking error exponentially converges towards a small region around zero, which is adjustable. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, robust containment problem is investigated for a class of multi-leader multi-agent linear systems in the presence of time-varying uncertainties. To achieve containment, a new kind of adaptive containment protocols are proposed for the multi-agent systems. Specifically, the designed protocols consist of a continuous linear term and a discontinuous term. The linear term of the designed protocol is employed to achieve containment while the discontinuous term is utilized to eliminate the effect of uncertain dynamics on the achievement of containment. By using tools from non-smooth analysis and algebraic graph theory, some efficient criteria for achieving robust containment in the closed-loop multi-agent systems are obtained and analyzed. One favorable property of the designed protocol is that containment in the closed-loop multi-agent systems can be achieved in a fully distributed fashion over any given connected and detail-balanced communication graph without using any global information about the communication graph. The effectiveness of the analytical results is finally verified by performing numerical simulations. Copyright © 2016 John Wiley & Sons, Ltd.

This paper presents a connection between dissipation inequalities and integral quadratic constraints (IQCs) for robustness analysis of uncertain discrete-time systems. Traditional IQC results derived from homotopy methods emphasize an operator-theoretic input–output viewpoint. In contrast, the dissipativity-based IQC approach explicitly incorporates the internal states of the uncertain system, thus providing a more direct procedure to analyze uniform stability with non-zero initial states. The standard dissipation inequality requires a non-negative definite storage function and ‘hard’ IQCs. The term ‘hard’ means that the IQCs must hold over all finite time horizons. This paper presents a modified dissipation inequality that requires neither non-negative definite storage functions nor hard IQCs. This approach leads to linear matrix inequality conditions that can provide less conservative results in terms of robustness analysis. The proof relies on a key *J*-spectral factorization lemma for IQC multipliers. A simple numerical example is provided to demonstrate the utility of the modified dissipation inequality. Copyright © 2016 John Wiley & Sons, Ltd.

This paper addresses the design of robust weighted fusion Kalman estimators for a class of uncertain multisensor systems with linearly correlated white noises. The uncertainties of the systems include the same multiplicative noises perturbations both on the systems state and measurement output and the uncertain noise variances. The measurement noises and process noise are linearly correlated. By introducing two fictitious noises, the system under consideration is converted into one with only uncertain noise variances. According to the minimax robust estimation principle, based on the worst-case systems with the conservative upper bounds of the noise variances, the four robust weighted fusion time-varying Kalman estimators are presented in a unified framework, which include three robust weighted state fusion estimators with matrix weights, diagonal matrix weights, scalar weights, and a modified robust covariance intersection fusion estimator. The robustness of the designed fusion estimators is proved by using the Lyapunov equation approach such that their actual estimation error variances are guaranteed to have the corresponding minimal upper bounds for all admissible uncertainties. The accuracy relations among the robust local and fused time-varying Kalman estimators are proved. The corresponding robust local and fused steady-state Kalman estimators are also presented, a simulation example with application to signal processing to show the effectiveness and correctness of the proposed results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper deals with the problem of stabilizing a class of input-delayed systems with (possibly) nonlinear uncertainties by using explicit delay compensation. It is well known that plain predictive schemes lack robustness with respect to uncertain model parameters. In this work, an uncertainty estimator is derived for input-delay systems and combined with a modified state predictor, which uses current available information of the estimated uncertainties. Furthermore, based on Lyapunov–Krasovskii functionals, a computable criterion to check robust stability of the closed-loop is developed and cast into a minimization problem constrained to an LMI. Additionally, for a given input delay, an iterative-LMI algorithm is proposed to design stabilizing tuning parameters. The main results are illustrated and validated using a numerical example with a second-order dynamic system. Copyright © 2016 John Wiley & Sons, Ltd.

This paper presents a new model reference adaptive control (MRAC) framework for a class of nonlinear systems to address the improvement of transient performance. The main idea is to introduce a nonlinear compensator to reshape the closed-loop system transient, and to suggest a new adaptive law with guaranteed convergence. The compensator captures the unknown system dynamics and modifies the given nominal reference model and the control action. This modified controlled system can approach the response of the ideal reference model. The transient is easily tuned by a new design parameter of this compensator. The nominal adaptive law is augmented by new leakage terms containing the parameter estimation errors. This allows for fast, smooth and exponential convergence of both the tracking error and parameter estimation, which again improves overall reference model following. We also show that the required excitation condition for the estimation convergence is equivalent to the classical persistent excitation (PE) condition. In this respect, this paper provides an intuitive and numerically feasible approach to online validate the PE condition. The salient feature of the suggested methodology is that the rapid suppression of uncertainties in the controlled system can be achieved without using a large, high-gain induced, learning rate in the adaptive laws. Extensive simulations are given to show the effectiveness and the improved response of the proposed schemes. Copyright © 2016 John Wiley & Sons, Ltd.

Time-varying group formation control problems for general linear multi-agent systems with directed topologies are studied. Different from the traditional complete formation, where only one formation is realized by the multi-agent system, in the group formation, there could be multiple time-varying sub-formations. Firstly, a time-varying group formation protocol is constructed by local neighboring relative information. Then nonsingular transformations are applied to the closed-loop multi-agent systems. Sufficient conditions for the multi-agent systems to achieve time-varying group formation are further presented together with the time-varying group formation feasibility constraints. Explicit expressions of the subgroup formation reference functions are derived to describe the macroscopic movement of the time-varying subgroup formations. Moreover, an approach to design the time-varying group formation protocol is proposed by solving an algebraic Riccati equation. Finally, a numerical example with three subgroups is provided to demonstrate the effectiveness of the obtained theoretical results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper presents a new observer-based controller design method for Lipschitz nonlinear systems with uncertain parameters and -bounded disturbance inputs. In the presence of uncertain parameters, the separation principle is not applicable even in the case of linear time invariant systems. A state of the art review for uncertain linear systems is first presented to describe the shortcomings and conservatism of existing results for this problem. Then a new LMI-based design technique is developed to solve the problem for both linear and Lipschitz nonlinear systems. The features of the new technique are the use of a new matrix decomposition, the allowance of additional degrees of freedom in design of the observer and controller feedback gains, the elimination of any need to use equality constraints, the allowance of uncertainty in the input matrix and the encompassing of all previous results under one framework. An extensive portfolio of numerical case studies is presented to illustrate the superiority of the developed design technique to existing results for linear systems from literature and to illustrate application to Lipschitz nonlinear systems. Copyright © 2016 John Wiley & Sons, Ltd.

This paper investigates the problem of state observer design for a class of nonlinear uncertain dynamical systems with interval time-varying delay and the one-sided Lipschitz condition. By constructing the novel Lyapunov–Krasovskii functional while utilizing the free-weighting matrices approach, the one-sided Lipschitz condition and the quadratic inner-bounded condition, novel sufficient conditions, which guarantee the observer error converge asymptotically to zero, are established for a class of nonlinear dynamical systems with interval time-varying delay in terms of the linear matrix inequalities. The computing method for observer gain matrix is given. Finally, two examples illustrate the effectiveness of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.

This paper deals with the design of a robust control for linear systems with external disturbances using a homogeneous differentiator-based observer based on a implicit Lyapunov function approach. Sufficient conditions for stability of the closed-loop system in the presence of external disturbances are obtained and represented by linear matrix inequalities. The parameter tuning for both controller and observer is formulated as a semi-definite programming problem with linear matrix inequalities constraints. Simulation results illustrate the feasibility of the proposed approach and some improvements with respect to the classic linear observer approach. Copyright © 2016 John Wiley & Sons, Ltd.

This paper addresses the robust consensus control design for input-delayed multi-agent systems subject to parametric uncertainties. To deal with the input delay, the Artstein model reduction method is employed by a state transformation. The input-dependent integral term that remains in the transformed system, owing to the model uncertainties, is judiciously analysed. By carefully exploring certain features of the Laplacian matrix, sufficient conditions for the global consensus under directed communication topology are identified using Lyapunov–Krasovskii functionals in the time domain. The proposed control only relies on relative state information of the subsystems via network connections. The effectiveness and robustness of the proposed control design are demonstrated through a numerical simulation example. Copyright © 2016 John Wiley & Sons, Ltd.

No abstract is available for this article.

]]>This paper presents an online recorded data-based design of composite adaptive dynamic surface control for a class of uncertain parameter strict-feedback nonlinear systems, where both tracking errors and prediction errors are applied to update parametric estimates. Differing from the traditional composite adaptation that utilizes identification models and linear filters to generate filtered modeling errors as prediction errors, the proposed composite adaptation integrates closed-loop tracking error equations in a moving time window to generate modified modeling errors as prediction errors. The time-interval integral operation takes full advantage of online recorded data to improve parameter convergence such that the application of both identification models and linear filters is not necessary. Semiglobal practical asymptotic stability of the closed-loop system is rigorously established by the time-scales separation and Lyapunov synthesis. The major contribution of this study is that composite adaptation based on online recorded data is achieved at the presence of mismatched uncertainties. Simulation results have been provided to verify the effectiveness and superiority of this approach. Copyright © 2016 John Wiley & Sons, Ltd.

In networked systems, intermittent failures in data transmission are usually inevitable due to the limited bandwidth of the communication channel, and an effective countermeasure is to add redundance so as to improve the reliability of the communication service. This paper is concerned with the model predictive control (MPC) problem by using static output feedback for a class of polytopic uncertain systems with redundant channels under both input and output constraints. By utilizing the min–max control approach combined with stochastic analysis, sufficient conditions are established to guarantee the feasibility of the designed MPC scheme that ensures the robust stability of the closed-loop system. In terms of the solution to an auxiliary optimization problem, an easy-to-implement MPC algorithm is proposed to obtain the desired sub-optimal control sequence as well as the upper bound of the quadratic cost function. Finally, to illustrate its effectiveness, the proposed design method is applied to control a networked direct current motor system. Copyright © 2016 John Wiley & Sons, Ltd.

This paper investigates the exponential observer design problem for one-sided Lipschitz nonlinear systems. A unified framework for designing both full-order and reduced-order exponential state observers is proposed. The developed design approach requires neither scaling of the one-sided Lipschitz constant nor the additional quadratically inner-bounded condition. It is shown that the synthesis conditions established include some known existing results as special cases and can reduce the intrinsic conservatism. For design purposes, we also formulate the observer synthesis conditions in a tractable LMI form or a Riccati-type inequality with equality constraints. Simulation results on a numerical example are given to illustrate the advantages and effectiveness of the proposed design scheme. Copyright © 2016 John Wiley & Sons, Ltd.

Intensive research in the field of mathematical modeling of pneumatic servo drives has shown that their mathematical models are nonlinear in which many important details cannot be included in the model. Owing the influence of the combination of heat coefficient, unknown discharge coefficient, and change of temperature, it was supposed that parameters of the pneumatic cylinder are random (stochastic parameters). On the other side, it has been well known that the nonlinear model can be approximated by a linear model with time-varying parameters. Due to the aforementioned reasons, it can be assumed that the pneumatic cylinder model is a linear stochastic model with variable parameters. In practical conditions, in measurements, there are rare, inconsistent observations with the largest part of population of observations (outliers). Therefore, synthesis of robust algorithms is of primary interest. In this paper, the robust recursive algorithm for output error models with time-varying parameters is proposed. The convergence property of the proposed robust algorithm is analyzed using the methodology of an associated ordinary differential equation system. Because *ad hoc* selection of model orders leads to overparameterization or parsimony problem, the robust Akaike's criterion is proposed to overcome these problems. By determining the least favorable probability density for a given class of probability distribution represents a base for design of the robust version of Akaike's criterion. The behavior of the proposed robust identification algorithm is considered through intensive simulations that demonstrate the superiority of the robust algorithm in relation to the linear algorithms (derived under an assumption that the stochastic disturbance has a Gaussian distribution). The good practical values of the proposed robust algorithm to identification of the pneumatic cylinder are illustrated by experimental results. Copyright © 2016 John Wiley & Sons, Ltd.

Exponential stability necessary conditions for linear periodic time-delay systems are presented. They are obtained with the help of new properties of the Lyapunov matrix in the framework of Lyapunov–Krasvoskii functionals of complete type. An academic example illustrates our results. Copyright © 2016 John Wiley & Sons, Ltd.

Reset control techniques have been proposed to overcome fundamental limitations of linear controllers by means of their transformation into hybrid models that combine continuous flow and discrete jump dynamics. The hybrid nature in the control loop involves some difficulties when analyzing the performance of the controller and some drawbacks on the controller design related to the stability conditions. The technique that we propose is based on sector confined target dynamics of the continuous flow mode by means of the application of the discrete reset jumps. This behavior, in the error plane , is correlated with certain preferred sectors that lead to fast and over-damped responses. The paper studies how to design a hybrid resetting version of a linear controller that achieves the required fast and over-damped responses to arbitrary references. Copyright © 2016 John Wiley & Sons, Ltd.

We study in this paper the problem of iterative feedback gains auto-tuning for a class of nonlinear systems. For the class of input–output linearizable nonlinear systems with bounded additive uncertainties, we first design a nominal input–output linearization-based robust controller that ensures global uniform boundedness of the output tracking error dynamics. Then, we complement the robust controller with a model-free *multi-parametric extremum seeking* control to iteratively auto-tune the feedback gains. We analyze the stability of the whole controller, that is, the robust nonlinear controller combined with the multi-parametric extremum seeking model-free learning algorithm. We use numerical tests to demonstrate the performance of this method on a mechatronics example. Copyright © 2016 John Wiley & Sons, Ltd.

The robustness properties of a first-order sliding-mode controller are combined with those of an added linear term in order to obtain a closed loop that shows input-to-state stability with respect to matched and unmatched disturbances, of which an upper bound might not be known, using only output information. The output under consideration can have any relative degree. Also, a transformation of the state into a novel output normal form is presented. The zero dynamics are considered unstable and perturbed, so a methodology for defining an observer and a virtual control for it is presented. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, we consider the stability issue of economic model predictive control (EMPC) for constrained nonlinear systems and propose a new contractive constraint formulation of nonlinear EMPC schemes. This formulation is one of Lyapunov-based approaches in which the contractive function chosen a priori can be used as a Lyapunov function. Some conditions are given to guarantee recursive feasibility and asymptotic stability of the EMPC. Moreover, we analyze the transient economic performance of the EMPC closed-loop system in some finite-time intervals. The proposed EMPC scheme is applied to a chemical reactor model to illustrate its utility and benefits. Copyright © 2016 John Wiley & Sons, Ltd.

Integral inequalities have been widely used in stability analysis for systems with time-varying delay because they directly produce bounds for integral terms with respect to quadratic functions. This paper presents two general integral inequalities from which almost all of the existing integral inequalities can be obtained, such as Jensen inequality, the Wirtinger-based inequality, the Bessel–Legendre inequality, the Wirtinger-based double integral inequality, and the auxiliary function-based integral inequalities. Based on orthogonal polynomials defined in different inner spaces, various concrete single/multiple integral inequalities are obtained. They can produce more accurate bounds with more orthogonal polynomials considered. To show the effectiveness of the new inequalities, their applications to stability analysis for systems with time-varying delay are demonstrated with two numerical examples. Copyright © 2016 John Wiley & Sons, Ltd.

This paper focuses on the analysis and the design of event-triggering scheme for discrete-time systems. Both static event-triggering scheme (SETS) and adaptive event-triggering scheme (AETS) are presented for discrete-time nonlinear and linear systems. What makes AETS different from SETS is that an auxiliary dynamic variable satisfying a certain difference equation is incorporated into the event-triggering condition. The sufficient conditions of asymptotic stability of the closed-loop event-triggered control systems under both two triggering schemes are given. Especially, for the linear systems case, the minimum time between two consecutive control updates is discussed. Also, the quantitative relation among the system parameters, the preselected triggering parameters in AETS, and a quadratic performance index are established. Finally, the effectiveness and respective advantage of the proposed event-triggering schemes are illustrated on a practical example. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, we claim the availability of deterministic noises for stabilization of the origins of dynamical systems, provided that the noises have unbounded variations. To achieve the result, we first consider the system representations of rough systems based on rough path analysis; then, we provide the notion of asymptotic stability for rough systems to analyze the stability for the systems. In the procedure, we also confirm that the system representations include stochastic differential equations; we also found that asymptotic stability for rough systems is the same property as uniform almost sure asymptotic stability provided by Bardi and Cesaroni. After the discussion, we confirm that there is a case that deterministic noises are capable of making the origin become asymptotically stable for rough systems while stochastic noises do not achieve the same stabilization results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper formulates and addresses the problem of equivalence in terms of multistability properties between nonlinear models of gene regulatory systems of different dimensionality. Given a nonlinear dynamical model of a gene regulatory network and the structure of another higher-dimensional gene regulatory network, the aim is to find a dynamical model for the latter that has the same equilibria and stability properties as the former. We propose construction rules for the dynamics of a high-dimensional system, given the low-dimensional system and the high-dimensional network structure. These construction rules yield a multistability-equivalent system, as we prove in this work. We demonstrate the value of our method by applying it to an example of a multistable gene regulatory network involved in mesenchymal stem cell differentiation. Here, differentiation is described by a core motif of three genetic regulators, but the detailed network contains at least nine genes. The proposed construction method allows to transfer the multistability based differentation mechanism of the core motif to the more detailed gene regulatory network. Copyright © 2016 John Wiley & Sons, Ltd.