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This paper proposes a control strategy integrating the non‐linear extended state observer (NLESO) and the non‐singular terminal sliding mode control (NTSMC) for the trajectory tracking of wheeled mobile robots subject to bounded disturbances. A new transformation method of chained model in terms of Lie derivative is presented to simplify the controller design. A specific NLESO combining linear term and non‐linear term is designed to estimate the disturbances with a faster convergence performance. A scheme for determining the gain range of NLESO is explicitly given to facilitate the tuning of experimental parameters. Meanwhile, the NTSMC achieves finite time convergence of the tracking error system and the chattering phenomenon in NTSMC is dramatically alleviated with the compensation from NLESO. The experimental results validate the strong robustness and good performance of the proposed control strategy. [ABSTRACT FROM AUTHOR]

Summary: In this paper, the resilient control problem is investigated for a wireless networked control system (WNCS) under denial‐of‐service (DoS) attack via a hierarchical game approach. In the presence of a wireless network, a DoS attacker leads to extra packet dropout in the cyber layer of WNCS by launching interference power. A zero‐sum Markov game is exploited to model the interaction between the transmitter and the DoS attacker under dynamic network environment. Additionally, with the attack‐induced packet loss, an H∞ minimax controller is designed in the physical layer by using a delta operator approach. Both value iteration and Q‐learning methods are used to solve the hierarchical game problem for the WNCS. The proposed method is applied to a load frequency control system to illustrate the effectiveness. [ABSTRACT FROM AUTHOR]

An adaptive extended state observer (AESO) based robust controller is proposed for precise position tracking control of a magnetic rodless cylinder with strong static friction. The AESO with dynamic gains is utilized to estimate the static friction and nonlinearities. Precise and robust control is achieved by the proposed controller that integrates the advantages of a sliding-mode controller and a linear active disturbance rejection controller. Experimental results show that both response rate and position accuracy are significantly improved by the proposed method in this paper. [ABSTRACT FROM PUBLISHER]

In this brief, attitude control is investigated for a quadrotor under gust wind via a dual closed-loop control framework. In the dual closed-loop framework, active disturbance rejection control and proportional–derivative control are used in the inner and outer loops, respectively. The perturbations of gust wind are considered as dynamic disturbances, which are estimated by an extended state observer in the inner loop. Both convergence and stabilization are given for the extended state observer and the closed-loop system, respectively. Experimental results are given to show the effectiveness of the proposed method for quadrotors. [ABSTRACT FROM AUTHOR]

Summary: This paper presents an event‐triggered predictive control approach to stabilize a networked control system subject to network‐induced delays and packet dropouts, for which the states are not measurable. An observer‐based event generator is first designed according to the deviation between the state estimation at the current time and the one at the last trigger time. A predictive control scheme with a selector is then proposed to compensate the effect of network‐induced delays and packet dropouts. Sufficient conditions for stabilization of the networked control system are derived by solving linear matrix inequalities and the corresponding gains of the controller and the observer are obtained. It is shown that the event‐triggered implementation is able to realize reduction in communication and save bandwidth resources of feedback channel networks. A simulation example of an inverted pendulum model illustrates the efficacy of the proposed scheme. [ABSTRACT FROM AUTHOR]

This paper studies the problem of robust fault-tolerant control against the actuator effectiveness loss for delta operator systems with actuator saturation. Ellipsoids are used to estimate the domain of attraction for the delta operator systems with actuator saturation and effectiveness loss. Some invariance set conditions used for enlarging the domain of attraction are expressed by linear matrix inequalities. Discussions on system performance optimisation are presented in this paper, including reduction on computational complexity, expansion of the domain of attraction and disturbance rejection. Two numerical examples are given to illustrate the effectiveness of the developed techniques. [ABSTRACT FROM AUTHOR]

This brief presents a novel control scheme for some problems on tracking and obstacle avoidance of a wheeled mobile robot with nonholonomic constraint. An extended state observer is introduced to estimate the unknown disturbances and velocity information of the wheeled mobile robot. A nonlinear controller is designed to achieve tracking target and obstacle avoidance in complex environments. Note that tracking errors converge to a residual set outside the obstacle detection region. Moreover, the obstacle avoidance is also guaranteed inside the obstacle detection region. Simulation results are given to verify the effectiveness and robustness of the proposed design scheme. [ABSTRACT FROM PUBLISHER]

This paper presents a new control scheme on trajectory tracking of wheeled mobile robot with nonholonomic constraints. Extended state observer is introduced to estimate unknown disturbances and velocity information. A robust tracking controller is designed to implement the accurate trajectory tracking and disturbance compensation. By theoretical, position and velocity tracking errors of wheeled mobile robot are proven uniformly ultimately asymptotically stable. Simulation results are given to illustrate the effectiveness of the developed technique. [ABSTRACT FROM PUBLISHER]

In this paper, the control problem of linear systems with periodic sampling period subject to actuator saturation is considered via delta operator approach. Using periodic Lyapunov function, sufficient conditions of local stabilization for periodic sampling systems are given. By solving an optimization problem, we derive the periodic feedback control laws and the estimate of the domain of attraction. As the saturation function sat. belongs to the sector OE0; 1, sufficient conditions are derived by constructing saturation-dependent Lyapunov functions to ensure that the periodic sampling system is globally asymptotically stable. A numerical example is given to illustrate the theoretical results proposed in this paper. [ABSTRACT FROM AUTHOR]

This study is concerned with the low‐frequency (LF) integral quadratic constraints (IQC) of the linear singularly perturbed model (SPM). The conditions satisfying LF IQC are derived in terms of linear matrix inequalities by using the generalised Kalman–Yakubovich–Popov lemma. As special cases of LF IQC, LF bounded realness and LF positive realness are exploited in detail. In addition, upper bound of the small perturbation parameter, which relates to the robustness of SPM, can be estimated. Numerical simulations demonstrate that the proposed method can reduce the conservatism and characterise the SPM more specifically by ignoring the unrelated frequency range. [ABSTRACT FROM AUTHOR]

This study is concerned with the robust stabilisation problem of networked delta operator systems with time delays and packet losses. To avoid the inherent drawback of the standard shift‐domain model at high sampling rates, the uncertain delta operator model is employed to describe the plant of networked control systems. Under this framework, by guaranteeing the deceasement of Lyapunov functional at each updating period rather than at each sampling period, a sufficient robust stability condition in terms of linear matrix inequalities is presented. Based on this criterion, the robust stabilising controller design method is also provided. The results acquired in this study are network parameters dependent in the sense that they depend on not only the bounds of time delays but also the bound of maximum consecutive packet losses. Numerical examples are given to show the effectiveness and potential of the developed theoretical results. [ABSTRACT FROM AUTHOR]

In this paper, robust stochastic stabilization problems for uncertain Markovian jump linear delta operator systems with actuator saturation are considered. The definition of the domain of attraction for a Markovian jump delta operator system in mean square sense is introduced to analyze the stochastic stability of the closed-loop system. By using a stochastic Lyapunov function which is dependent on the jump mode, design procedures for a mode-dependent state feedback controller are developed based on linear matrix inequality approach. A mode-independent state feedback controller is also designed by using a mode-independent Lyapunov function. Some simulation results are given to illustrate the effectiveness of the developed techniques. [ABSTRACT FROM AUTHOR]

The problem of robust H ∞ control for uncertain discrete-time Takagi and Sugeno (T-S) fuzzy networked control systems (NCSs) with state quantisation is investigated. A new model of network-based control with simultaneous consideration of network-induced delays and packet dropouts is proposed. By using a fuzzy Lyapunov–Krasovskii functional (LKF), we derive a less conservative delay-dependent stability condition for the closed-loop NCSs. Robust H ∞ fuzzy controller is developed for the asymptotical stabilisation of the NCSs. Since it is not expressed as strict LMI conditions, the cone complementary linearisation procedure is exploited to solve the nonconvex feasibility problem. A numerical example shows the feasibility applications of the proposed technique. [ABSTRACT FROM PUBLISHER]

This paper investigates the problem of stability for a class of linear uncertain Markovian jump systems over networks via the delta operator approach. The sensor-to-controller random network-induced delay and arbitrary packet losses are considered for mode-dependent time delays. That is, a Markov process is used to model the time-varying delays which are dependent on the system mode. Based on the Lyapunov-Krasovskii functional in the delta domain, a new sufficient condition for the solvability of the stability problem is presented in terms of linear matrix inequalities. A numerical example is given to illustrate the effectiveness of the techniques developed. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of fault detection for Takagi–Sugeno (T–S) fuzzy discrete systems in finite-frequency domain. By means of the T–S fuzzy model, both a fuzzy fault detection filter system and the dynamics of filtering error generator are constructed. Two finite-frequency performance indices are introduced to measure fault sensitivity and disturbance robustness. Faults are considered in a middle frequency domain, while disturbances are considered in another certain finite-frequency domain interval. By using the generalized Kalman–Yakubovi\brevec–Popov Lemma in a local linear system model, the design methods are presented in terms of solutions to a set of linear matrix inequalities, which can be readily solved via standard numerical software. The design problem is formulated as a two-objective optimization algorithm. A numerical example is given to illustrate the effectiveness and potential of the developed techniques. [ABSTRACT FROM PUBLISHER]