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This paper addresses the multiple fault estimation problem for the switched linear systems with actuator and sensor faults. By introducing an intermediate variable and augmenting state and sensor faults into a new vector, an fault estimation approach is proposed to contemporaneously estimate the state, the actuator and sensor faults. It is shown that under switching signals with average dwell time closed-loop signals remain uniformly ultimately bounded. Finally, a case study is given to illustrate the effectiveness of the proposed scheme.

This paper investigates the average tracking problem for a class of nonlinear multi-agent systems with switching topologies. The control design is developed for switching topologies without requiring the accurate mode with nonlinear dynamics. An adaptive neural-network-based control algorithm is proposed for a team of agents to track the average of multiple time-varying reference signals, of which the dynamics of each subsystem is assumed to be unknown and will be estimated by using adaptive neural network mechanism. Finally, a numerical simulation is given to illustrate the effectiveness of presented consensus protocol.

Summary The consensus problem for multi-agent systems with input saturation is addressed in this paper. For agents with double-integrator dynamics, we first propose two consensus algorithms, respectively, for the cases with and without velocity measurements. Based on graph theory, homogeneous method and the Lyapunov stability theory, it is proved that the proposed algorithms can guarantee not only the state agreement in finite time for all the agents but also the input saturation requirement. Then, the obtained results and techniques are extended to the finite-time consensus problem for multiple mechanical systems. Numerical simulations are finally provided to verify the effectiveness of the theoretical results. Copyright © 2015 John Wiley & Sons, Ltd.

Coordination control problem of networked Euler-Lagrange systems with external disturbance is addressed. The sliding mode surface and coordination control law of networked Euler-Lagrange systems with a dynamic leader under a directed graph is first proposed. It is shown that the followers can track the dynamic leader in finite time. Then leaderless consensus law for networked Euler-Lagrange systems is proposed. Based on algebraic graph theory and Lyapunov stability theory, finite-time stability of the closed-loop system is proven. The simulation results show the feasibility and effectiveness of the proposed control law.

In this paper, attitude coordination control problem for multiple rigid bodies under a directed communication topology is studied. A distributed control algorithm of multiple rigid bodies in the presence of time-varying communication delays is designed, and with Lyapunov theory and algebraic graph theory, rigorous proof of global asymptotical stability of closed-loop system is given. Then, considering external disturbance, the uncertainty of inertia moment and time-varying communication delays exist simultaneously, an adaptive sliding mode control algorithm for multiple rigid bodies is designed to guarantee the attitude synchronization. Finally, numerical simulations are provided to illustrate the feasibility and effectiveness of the designed distributed control algorithms.

This paper addresses coordinated attitude control problem for multiple rigid bodies. Based on graph theory and Lyapunov stability theory, distributed coordinated attitude control laws are designed. The proposed control laws guarantee that each rigid body attains desired time-varying attitude and angular velocity while maintaining attitude synchronization with other rigid body. Furthermore, attitude tracking and synchronization without angular velocity measurements and with input constraints is also discussed.

In this paper we consider distributed attitude synchronization problem for multiple rigid bodies with time delays in the intercommunication. Based on graph theory and Lyapunov stability theory, we propose two distributed control laws. The first control law can guarantee attitude synchronization with zero final angular velocities when time delays exist. The second control law can guarantee attitude synchronization with non-zero final angular velocities when time delays exist. Throughout the paper, the communication flow among rigid bodies is assumed to be fixed and undirected.

In this paper, we study the finite-time consensus problem for multi-agent systems with double-integrator dynamics. Considering the case that the velocity is not available for feedback and the control inputs are required to be a priori bounded, the velocity-free consensus algorithm is proposed, in which, the graph theory, homogeneous method and Lyapunov stability theory are applied. The proposed velocity-free algorithm guarantees that the states of all agents can reach consensus in finite time and satisfies input saturation requirement. Numerical simulation is provided to validate the effectiveness of the proposed method.

In this paper, we propose two finite-time control laws for rigid spacecraft. We use quaternion for attitude representation and employ the Lagrange-like model for convenience of system design. First, by using the finite-time control method, a full-state feedback control scheme is presented. Then, considering no angular velocity measurement can be obtained, we propose a finite-time control law. Under the proposed control laws, the attitude of spacecraft converge to desired attitude in finite time.

In this paper we consider coordinated control problem of a spacecraft formation consisting of two spacecrafts. Two sliding control schemes are designed to guarantee attitude tracking and synchronization of formation spacecrafts under uncertainty in spacecraft inertia parameters and external disturbance. The second adaptive sliding mode tracking control scheme can also implement real-time identification of inertia parameters. Global asymptotical stability of the spacecraft of formation is proven mathematically. Finally, simulations are performed and simulation results demonstrate the proposed control scheme is effective and feasible.

In this paper we consider attitude coordination control problem of spacecraft formation flying. Two coordinated attitude tracking control schemes subject to control input constraints are addressed here. We first present the full-state feedback control scheme that allows each spacecraft to align their attitude and track the desired trajectory. Then the output feedback control schemes are given without the requirement of absolute angular velocity measurements and relative angular velocity measurements between neighboring spacecrafts. By introducing bounded functions we can get the desired bounds on the control torques. Simulation results of a scenario of six spacecrafts are provided to show the effectiveness of the proposed attitude coordination control schemes.

This paper deals with the problem of attitude tracking control of rigid satellite subject to external disturbance, and parametric uncertainty. An adaptive controller is designed to implement real-time identification for inertia parameters and control parameter is adjusted dynamically. A detail stability analysis of the close loop system is included and system is finite-gain L 2 stable. Simulations are performed for the satellite attitude control system. Simulation results demonstrate that the control scheme realizes the attitude tracking control and implements identification for inertia matrix and effective rejection for disturbances.

The main problem addressed is modified Rodrigues parameter (MRP) based, attitude tracking control of rigid satellite. First a nonlinear control scheme is presented under control input saturation. The control scheme is shown to achieve global asymptotic stability for the whole tracking error states through a rigorous Lyapunov analysis. Then we give a control scheme not only to deal with the control input saturation but also error angular velocity constraints, and a detail stability analysis of the closed-loop is included. Numerical simulations are performed for the satellite attitude tracking control system and results demonstrate the effective of the proposed control schemes.

The main problem addressed is the attitude tracking control of rigid satellite in the presence of inertia matrix uncertainty and external disturbances. A sliding mode controller with PID sliding surface is presented. A detail stability analysis of the close loop system is include, and while there exists uncertainty in satellite inertia parameters or external disturbance, this control scheme has global stability and robustness. Simulations are performed for the satellite attitude control system. Simulation results demonstrate that the control scheme realizes the attitude tracking control and is robust to parametric uncertainty and to external disturbance torques.

Servicer is required to fast attitude capture after capturing/releasing target. Considering the variable model and nonzero initial angular rate, the paper presents a model independent control law to realize the attitude capture by a move-to-rest eigenaxis rotation. The law adopts the attitude information and the deviation information of eigenaxis to enable the servicer to perform attitude capture rapidly within constraints of slew rate and control torque by the cascade-saturation control logic. Finally, a simulation is also illustrated, and the results prove that the law has validity and reliability.