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This article considers the design problem of H∞$$ {H}_{\infty } $$ observer‐based fault‐tolerant control under three faulty cases: sensor only, actuator only, and both sensor and actuator faults. To save communication resources, the event trigger mechanism method is used for sensor‐to‐observer and observer‐to‐controller transmissions. In this case, the design method of the new H∞$$ {H}_{\infty } $$ observer is given for obtaining estimating both states and faults which are used to design observer‐based H∞$$ {H}_{\infty } $$ fault‐tolerant controllers. In particular, the virtual observer is designed to suppress the effects of faults on the system. As the virtual observer contains unmeasurable system information, the real observer is built on top of the virtual observer to eliminate the unmeasurable information. Finally, the feasibility of the approach is tested with a numerical example. [ABSTRACT FROM AUTHOR]

Road surface condition (RSC) is an important indicator in road safety studies, enabling transportation departments to employ it for conducting surveys, inspections, cleaning, and maintenance, ultimately contributing to improved performance in road upkeep. However, traditional recognition methods can be easily affected when extreme weather frequently occurs such as winter seasonal changes. To achieve real-time and automatic RSC monitoring, this paper proposes an improved Mask–region-based convolutional neural network (RCNN) based on Swin Transformer-PAFPN and a dynamic head detection network. Meanwhile, transfer learning is used to reduce training time, and data enhancement and multiscale training are applied to achieve better performance. The experimental results show that the proposed model achieves an outstanding mean average precision at 0.5 (mAP@0.5) score of 89.8 under favorable weather conditions characterized by clear visibility, surpassing other popular methods. Notably, the proposed model exhibits lower parameters and GigaFLOPS (GFLOPs) (72.41 and 158.35, respectively) compared to other popular methods, thus demanding fewer computational resources. Furthermore, in challenging weather conditions characterized by poor visibility, such as foggy and nighttime scenarios, the proposed model achieves mAP@0.5 scores of 78.50 and 82.40, respectively. These scores not only outperform those of other popular methods but also underscore the robustness of the proposed model in extreme weather conditions. This exceptional performance demonstrates the proposed model's effectiveness in addressing complex road conditions under various meteorological circumstances, providing reliable technical support for practical traffic monitoring and road maintenance. [ABSTRACT FROM AUTHOR]

This article aims to address the stochastic scaled consensus issue in almost surely and mean square sense of stochastic multiagent systems (SMASs) with compound noises in a Markovian switching setting. At first, based on stochastic approximation technique and nearest‐neighbor interaction rules, the stochastic scaled consensus controller is built for SMASs in presence of multiplicative and additive noise by designing a time‐varying gain. Meanwhile, some consensus criterions of SMASs are addressed if the union of the graph and time‐varying gain fulfill some mild requirements. Furthermore, the scaled consensus means that the agents' state variables tend to a prescribed proportion rather than the common value, so this behavior can be seen as non‐convergent behavior. The difference with most of excellent literatures is that the coexistence of noncooperative behavior and multiplicative noise generates that it is not easy to transform the multiplicative noise term into the form of an error equation, which means that the Lyapunov methods cannot be directly utilized in our article. To cope with this, we first demonstrate the boundedness for each agent's state, and hence the convergence can be achieved. Finally, in order to reveal the efficiency of our proposed protocol, the corresponding example is given in the simulation part. [ABSTRACT FROM AUTHOR]

This article studies the design problem of fault-tolerant and disturbance rejection control for leader-following multi-agent systems with polynomial form fault. First, a novel observer is designed to estimate polynomial form faults and external disturbances in the tracker. Second, a fault-tolerant control protocol is designed for each follower based on the obtained estimates; the designed distributed controller can effectively achieve both the goal of fault-tolerant control and the effect of disturbance rejection. Finally, a simulation result of a practical example is presented to verify the feasibility of the proposed scheme. [ABSTRACT FROM AUTHOR]

This paper is devoted to the research of adaptive command filter tracking control for a class of uncertain nonlinear systems. The coexistence of multiple coupling high‐order terms, uncertain external disturbances, and unknown time‐varying coefficients makes the studied system more general compared with the existing results. By skillfully combining adaptive technology, command filter control, and backstepping method, a new type of adaptive command filter tracking control algorithm is designed. This controller not only solves the problem of complex explosion but also introduces compensation signals to achieve a higher precision tracking effect. Ultimately, the validity of the control algorithm is verified by a numerical simulation and a practical application model simulation. [ABSTRACT FROM AUTHOR]

This paper is devoted to work out a stabilized controller by state feedback for a class of nonlinear systems. In this paper, we not only extend the existing results that system has a single power term to the case with multiple coupling power terms, but also consider that the power is time varying, which makes the system studied in this paper more general than that in other literature. By the backstepping method, a linear easy-to-implement controller is designed, which not only ensures the stability of the system but also has a good convergence speed. Finally, with a representative numerical example, by calculating all the parameters in the design procedure, the simulation shows that all the responses of the states and the controller are asymptotically stable at the equilibrium zero, which verifies the effectiveness of the control design scheme of this paper. [ABSTRACT FROM AUTHOR]

Under the event-triggered scheme, this note focuses on the problem of finite-time stability analysis of the switched system with controller failure and external interference. Firstly, in order to save network communication resources, the mixed event-triggered condition is considered. This mechanism can not only avoid Zeno phenomenon, but also use the sampled information more effectively. In addition, the saturation characteristics of the actuator are fully considered, which can further reduce the number of triggers. According to different event-triggered conditions, an algorithm is proposed to estimate the attraction domain. Then, through the Lyapunov-Krasovskii functional approach and average dwell time technology, the closed-loop switched system is analyzed. The determination condition of finite-time stability is obtained. To illustrate the advantages of our established results, a numerical example is finally given. In addition to saving communication resources, the system stability is guaranteed. The advantages of the proposed method can be verified by simulation. [ABSTRACT FROM AUTHOR]

This paper considers the output feedback finite-time stabilization in probability for a class of large-scale high-order stochastic nonlinear feedforward systems. The output feedback finite-time stabilized controller in probability is firstly designed for the nominal systems by the adding one power integrator. Then with the homogeneous domination method, by introducing an appropriate coordination, an equivalent system of the original system with tunable gain is obtained. After that, by constructing a observer and determining the tunable gains, the output feedback stabilized controller in probability of the original systems is finally given and analysed. [ABSTRACT FROM AUTHOR]

A cart‐double pendulum system is an underactuated mechanical system that has three degrees of freedom (DOF) and has two actuators. This paper discusses the stabilizing control problem for this non‐linear mechanical system. First, an input relationship is constructed to transform the 3‐DOF cart‐double pendulum system into a 2‐DOF reduced‐order system in a fixed time. Second, a swing‐up controller is designed for the reduced‐order system to make the system infinitely approach upright equilibrium point. After that, the swing‐up controller switches to a fixed‐time balance stabilization controller, which stabilizes the cart‐double pendulum at the upright equilibrium point in a fixed time. Finally, numerical examples verify the effectiveness of this presented control strategy. [ABSTRACT FROM AUTHOR]

Based on the traditional control approach, the position-tracking performance of the teleoperation system with communication delay is generally asymptotically stable. In practical applications, the closed-loop system is expected to achieve stable and finite-time convergence performance. A novel finite-time bilateral control scheme for a telerobotics system with communication delay is presented in this paper. On the basis of the traditional proportional damping injection control, this paper proposes and designs a new finite-time control method by introducing the non-integer power to the position error, velocity, and the combined error with position error and velocity. In comparison to existing proportional damping injection and finite-time control structures, the proposed method not only achieves the finite-time convergence performance of position tracking, but it also has the advantages of a simple structure and fewer gain coefficients. The controller also incorporates the radial basis function (RBF) neural network and adaptive approach to compensate unknown dynamics and external forces, thus also avoiding the measurement of force signals. The Lyapunov–Krasovskii function is then defined, and it is demonstrated that the position tracking of closed-loop teleoperation system has bounded stability and finite-time control performance. The simulation experiment is also performed, and the results further illustrated the bounded stability of the system. Moreover, compared to the position tracking errors of other non-finite-time control methods, it is demonstrated that the proposed finite-time control scheme has a faster convergence rate and higher convergence precision. [ABSTRACT FROM AUTHOR]

This article studies the simultaneous fault‐tolerant control and disturbance rejection for systems with fault in polynomial form. The unknown external disturbance is considered to be caused by the external source system, and the fault can be expressed as a polynomial function of time. Combining the fault observer and the disturbance observer, a controller is designed, which can not only diagnose the fault, but also improve the anti‐disturbance performance. Finally, a numerical example is given to verify the validity of the results. [ABSTRACT FROM AUTHOR]

Communication delay is an important factor affecting the stability and performance of telerobotic systems. In this paper, a new adaptive proportional damping controller is proposed to improve the stability and performance of the system in the presence of the cases such as asymmetric communication delay, unknown gravity torque, friction torque, and other disturbance torques. The proposed proportional damping control method combines the RBF neural network and adaptive control strategy to compensate for the unknown torque. The stability and robustness of the system are enhanced by adding error-damping items, operator force, and environmental force items. The Lyapunov–Krasovskii functional is employed to analyze and prove the exponential stability and signal boundedness of the closed-loop system. The simulation results verify the correctness of the proposed method, and the comparison with the results of other control methods shows the effectiveness of the designed control strategy. [ABSTRACT FROM AUTHOR]

Summary: This article studies the adaptive control for synchronization of semi‐linear complex spatio‐temporal networks (CSNs). And the leader‐following and leaderless CSN with time‐invariant coupling delay and time‐variant coupling delay are developed separately from two aspects. The adaptive control strategies are proposed to reach the asymptotic convergence of synchronization error. Synchronization criteria and sufficient conditions are obtained for the leader‐following CSN error model and leaderless CSN error model by constructing the apposite Lyapunov–Krasovskii functions and applying Wirtinger's inequality. Finally, two experimental examples are given to verify the feasibility of the theories proposed in this article. [ABSTRACT FROM AUTHOR]

A translational oscillator with a rotational actuator (TORA) is an underactuated nonlinear mechanical system with two degrees of freedom (DOF). This paper concerns the robust stabilization control problem for the system with multiple external disturbances. First, a disturbance observer is constructed based on the internal nonlinear dynamic behavior of the system. Second, a robust stabilization controller is designed by the estimated disturbances and the fixed-time sliding mode control method. The controller realizes the global robust stabilization control objective of the TORA system, and the stability of both disturbance observer and robust closed-loop control system are analyzed using the Lyapunov theorem. Finally, the effectiveness of the theoretical results are verified by numerical experiments. [ABSTRACT FROM AUTHOR]

We present several new matrix inequalities which connect the Schur complement, sector matrices and weighted arithmetic mean, geometric mean and harmonic mean, extending a key result in Lin [Extension of a result of Hanynsworth and Hartfiel. Arch Math. 2015;1:93–100]. [ABSTRACT FROM AUTHOR]

A spring-coupled three-link horizontal manipulator (STHM) is an underactuated mechanical system that possesses two control inputs and three degrees of freedom (DOF). This paper discusses the stabilization control problem for this multi-DOF underactuated system. By using an energy-absorbing idea, we design two types of virtual friction controllers: PsD controller and PD controller. Additionally, the stability of the control system is analyzed based on Lyapunov theory and LaSalle's invariance principle. The design of the stabilizing controller in this paper makes good use of the physical characteristics of the STHM system. The design process of the whole control system is simple. Numerical examples demonstrate the validity and superiority of our developed control strategy. [ABSTRACT FROM AUTHOR]

There are few results concerning consensus of multiagent systems (MASs) based on partial differential equations (PDEs), and the problem of how to act boundary control based on distributed measurement on spatial boundary points of MASs has not been solved. This paper addresses boundary control based on distributed measurement for output consensus of leader-following directed MASs modeled by parabolic PDEs. First, a boundary controller acting on spatial boundary points is designed by considering the delivered information produced by agents communicating with neighborhoods. Without considering input constraint, the Lyapunov’s direct method is used to obtain a sufficient condition on the existence of the boundary controller to achieve output consensus. The condition is expressed as a form of the feasibility of LMIs. After that, the whole input constraint for MASs is given. And then, one more condition on control gains is obtained to ensure the existence of the boundary controller with input constraint. Finally, one numerical example with two cases illustrates the theoretical analysis results. [ABSTRACT FROM AUTHOR]

This paper investigates the event-triggered containment control problem of a class of uncertain nonlinear multiagent systems (MASs). By employing the local relative information, we design an adaptive event-triggered containment algorithm. The proposed containment algorithm can cope with the unavailability of global topology information and uncertain dynamics of follower agents. Therefore, the presented containment algorithm is free of global topology information, i.e., the designed algorithm is fully distributed. In addition, it is proved that Zeno behavior will not occur. At last, a numerical example is given to verify our event-triggered containment algorithm. [ABSTRACT FROM AUTHOR]

A WAcrobot is an underactuated nonlinear system that has three degrees of freedom (DOF) and two inputs. This paper discusses the global stabilization control problem for this 3-DOF underactuated system. A new control strategy is developed to solve this problem. The strategy first changes the 3-DOF WAcrobot system to be a 2-DOF reduced-order model in finite time. This transforms the stabilizing control of the WAcrobot system into that of the reduced-order model. After that, nonsingular control laws that globally stabilize the reduced-order model at the origin are designed. It guarantees the stabilizing control objective of the WAcrobot to be achieved. Finally, a simulation experimental example demonstrates the validity of the presented theoretical results. Simulation results show the advantage of our strategy over others. [ABSTRACT FROM AUTHOR]

An underactuated horizontal spring-coupled two-link manipulator (UHSTM) is a nonlinear system that has one actuator and two degrees of freedom (DOF). This paper analyzes the nonlinear dynamics and develops a new global stabilization control method for this 2-DOF underactuated system. First, a set of suitable state variables are constructed to change the UHSTM system into a cascade nonlinear system. Second, a Lyapunov function is constructed based on the structural characteristics of the cascade system. A control law is designed to ensure the closed-loop control system to be Lyapunov stable. After that, the global asymptotical stability conditions are derived from the analysis of the closed-loop control system. Finally, numerical examples demonstrate the validity of the theoretical analysis results. [ABSTRACT FROM AUTHOR]

Summary: A cart‐pendulum system is a nonlinear underactuated mechanical system with two degrees of freedom. This paper addresses the motion trajectory design and tracking control problems for this underactuated system. First, a friction‐like control law is designed for the system. Then, the characteristics of the closed‐loop control system are analyzed. Second, a new method of constructing an optimal trajectory for the system is developed. Then, a tracking control law is designed to quickly track the constructed trajectory. It guarantees that the motion control of the cart‐pendulum system is achieved along a reference trajectory. Finally, a numerical example is presented to demonstrate the effectiveness of the theoretical results. This study constructs an optimal trajectory for the cart‐pendulum system in its whole motion space and solves the motion control objective by tracking the constructed trajectory. It has many advantages compared with other motion control methods, eg, the optimal motion control objective of the system is achieved by a single control law; and the motion process and transient characteristics (eg, the settling time) of the control system can be accurately predicted. [ABSTRACT FROM AUTHOR]

A translational oscillator with a rotational actuator (TORA) is an underactuated mechanical system with two degrees of freedom. This paper presents a new method to solve the global stabilisation control problem for this underactuated system. First, a set of suitable state variables is chosen for the TORA. It transforms the system into a cascade affine nonlinear system. Then, a positive-definite Lyapunov function is constructed based on the structural characteristics of the system. A control law is designed to guarantee that the derivative of the Lyapunov function is non-positive. Finally, the global stability of the closed-loop control system is analysed using the Lasalle invariance principle. The condition on the control parameters is presented to globally stabilise the TORA at the origin. The effectiveness and robustness of the method are verified by a numerical example. [ABSTRACT FROM AUTHOR]

Summary: In this paper, we investigate the pinning synchronization of directed complex network with time‐varying delay under the adaptive aperiodically intermittent control. First, the model of a directed complex network is established, the interaction graph of which is not required to contain a directed spanning tree, and for which an adaptive aperiodically intermittent feedback controller is well designed. In addition, based on the Lyapunov function method and linear matrix inequality technique, several asymptotical synchronization criteria are derived via an aperiodically intermittent strategy, which is superior to the periodical scheme. Moreover, the adaptive strategy providing the exponential convergence rate and the pinning algorithm demonstrating how to select pinned nodes are presented. Finally, numerical examples are provided to illustrate the effectiveness of the derived theoretical results. [ABSTRACT FROM AUTHOR]