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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]

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]

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]

This paper investigates the distributed event-triggered control problems of second-order nonlinear multi-agent systems (MASs) with directed graph. Firstly, an event-triggered consensus algorithm is developed for second-order nonlinear MASs. It is proved that MASs reach practical consensus and Zeno-behavior doesn't occur. Secondly, for leader–follower MASs, an event-triggered tracking algorithm is presented, which ensures that follower agents track leader agent even when leader agent has a nonzero input. Finally, a numerical simulation is given to show effectiveness of the proposed consensus algorithm. [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]

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]

This paper presents a new control strategy for an underactuated horizontal two-link flexible manipulator (HTFM) to realize the global stabilization. First, a homeomorphous coordinate transformation is introduced to the original manipulator system to create a new simple nonlinear system. Then, the new system is divided into the linear and nonlinear parts, and the idea of equivalent-input-disturbance (EID) is used to design a controller that globally and asymptotically stabilizes the new system as goal. The global stabilization control problem for the underactuated HTFM is soloved by the fact that the transformation is homeomorphous. The presented control method just adopts the position information of HTFM to design the stabilizing controller, which can not only reduce the cost of the control system, but also avoid the influence of velocity noises on the control performance effectively. The simulation results show that the stabilizing motion process, stabilizing time and other performances of the underactuated HTFM can achieve satisfactory results. [ABSTRACT FROM AUTHOR]