A finite-time attitude tracking control scheme is proposed for spacecraft using terminal sliding mode and Chebyshev neural network (NN) (CNN). The four-parameter representations (quaternion) are used to describe the global representation without singularities. state (i.e., velocity) error dynamics transformed a double integrator with constraint on attitude. With consideration of this constraint, novel manifold spacecraft. In order guarantee that output NN in controller bounded by...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A controller is proposed for the robust backstepping control of a class nonlinear pure-feedback systems using fuzzy logic. The scheme utilizes logic to learn behavior unknown plant dynamics. Filtered signals are employed circumvent algebraic loop problems encountered in implementation usual controllers, and approximation errors can be efficiently counteracted by employing smooth compensators....

This brief investigates the finite-time output feedback attitude control of a rigid spacecraft. First, nonlinear observer is designed. Through geometric homogeneity and Lyapunov theories, it shown that proposed can achieve semiglobal stability. Then, controller based on observer. Rigorous proof shows law ensures stability guarantees spacecraft to track time-varying reference in finite time. Simulation results are presented illustrate performance controller.

In this article, we consider the attitude tracking control problem for rigid spacecraft with bounded external disturbances. We propose a predefined-time predefined-bounded scheme based on nonsingular sliding-mode manifold. The proposed controller is continuous and it can achieve stability. That is, errors are driven to region around origin within predefined time, which be set as tuning parameter during design, independently of initial conditions. Finally, numerical simulations carried out...

This paper investigates the tracking control of an electrically driven nonholonomic mobile robot with model uncertainties in kinematics, dynamics, and wheel actuator dynamics. A robust adaptive controller is proposed utilization control, backstepping fuzzy logic techniques. The scheme employs approach to design auxiliary velocity make error as small possible consideration kinematics robot, makes use systems learn behaviors unknown dynamics actuators. approximation errors external...

A distributed attitude coordination control scheme using terminal sliding mode (TSM) is proposed for a group of spacecraft in the presence external disturbances. novel fast manifold presented, and robust term based on hyperbolic tangent function employed to suppress bounded The finite-time stability overall closed-loop system guaranteed by Lyapunov-based approach, numerical simulations are presented demonstrate performance controller.

This paper investigates the problem of output feedback attitude control an uncertain spacecraft. Two robust adaptive controllers based on Chebyshev neural networks (CNN) termed (NN) controller-I and NN controller-II are proposed for tracking The four-parameter representations (quaternion) employed to describe spacecraft global representation without singularities. nonlinear reduced-order observer is used estimate derivative output, CNN introduced further improve performance through...

This brief considers the attitude coordination control problem for spacecraft formation flying when only a subset of group members has access to common reference attitude. A quaternion-based distributed scheme is proposed with consideration input saturation and aid sliding-mode observer, separation principle theorem, Chebyshev neural networks, smooth projection algorithm, robust technique. Using graph theory Lyapunov-based approach, it shown that controller can guarantee all converge...

This article addresses the issue of output-feedback consensus control multiagent systems under directed topology and subject to bounded external disturbances. By employing a smooth time-varying function, distributed practical predefined-time (PPT) observer is developed estimate reference trajectory for entire team (i.e., leader's state) preset-time extended-state also proposed disturbances unmeasurable system states. Next, novel continuous nonsingular PPT law designed on basis observers....

This paper addresses the finite-time attitude tracking control problem for rigid spacecraft subject to magnitude constraints on both angular velocities and torques. The nonlinear transformation technique an smooth saturation model-based method are introduced tackle with of multiple constraints. Through input model, constraint issue is converted a bounded transformed states model input. Then, scheme proposed based backstepping approach robust technique. With derived law, errors can be driven...

This paper investigates the problem of velocity-free attitude coordination control for a group spacecraft with represented by modified Rodrigues parameters. The communication flow among neighbor is described an undirected connected graph. Two schemes are proposed. By employing linear reduced-order observers, robust and Chebyshev neural networks, first scheme allows to simultaneously align their track time-varying reference even in presence unknown mass moment inertia matrix external...

SUMMARY This paper investigates the problem of consensus tracking control for second‐order multi‐agent systems in presence uncertain dynamics and bounded external disturbances. The communication flow among neighbor agents is described by an undirected connected graph. A fast terminal sliding manifold based on lumped state errors that include absolute relative proposed, then a distributed finite‐time controller developed using mode Chebyshev neural networks. In proposed scheme, networks are...

Summary This paper investigates the problem of attitude tracking control spacecraft subject to input magnitude and rate saturations. The smooth hyperbolic tangent function is used model As system non‐affine in input, an augmented plant presented facilitate development law. backstepping technique, robust adaptive approaches are applied design stability closed‐loop guaranteed by Lyapunov method. Numerical simulations demonstrate performance proposed controller. Copyright © 2015 John Wiley...

This paper examines attitude coordination control for spacecraft formation flying. A class of distributed adaptive fault-tolerant laws is proposed. The proposed do not require online identification failures. Using the Lyapunov approach and graph theory, it shown that guarantee a group simultaneously track common time-varying reference attitude, even when available only to subset members group. Finally, numerical simulation presented show controller successful in achieving high-attitude...

This article considers the problem of velocity-free fixed-time attitude tracking control for rigid spacecraft. With help homogeneity theorem, a semiglobal observer is introduced to estimate unmeasured angular velocities within fixed time. Then, controller designed make spacecraft track time-varying reference signal in finite time, which can be up bounded by number regardless initial conditions. Finally, numerical examples are provided illustrate efficiency present scheme.

This paper considers the problem of attitude tracking control for uncertain rigid spacecraft subject to input magnitude and rate saturation (MRS). First, a smooth MRS model is proposed. Then, robust scheme designed based on backstepping finite-time disturbance observer techniques. Finally, effectiveness derived here illustrated by numerical simulations.

An adaptive control approach is proposed to deal with the multiple manipulators consensus problem based on multi-agent theory. In current literature, agents were assumed have determined models. However, practical manipulator's kinematics contains uncertain parameters. By using projection method, updating law for kinematic parameters derived. Then, estimated manipulator Jacobian matrix can be obtained design decentralized controller. controller, all manipulators' end-effectors move towards...

This paper considers output feedback attitude coordination control for spacecraft formation flying using quaternion-based parameterization. Using finite-time observers, reduced-order and backstepping technique, a distributed scheme is proposed. Through Lyapunov approach graph theory, it shown that the law guarantees group of simultaneously tracking common time-varying reference even when available only to subset members group. The results numerical simulation show controller successful in...

This paper investigates the distributed attitude synchronization and tracking control for multiple rigid bodies when a common time-varying reference is available to only subset of group members. The unit quaternion used representation because its globally nonsingular property. A decentralized sliding mode observer presented obtain an accurate estimate in finite time. Two coordination schemes are proposed based on separation principle. angular velocity measurements required first scheme while...

This study considers the problem of attitude tracking control for rigid spacecraft subject to input saturation. To address this problem, a smooth model is first proposed describe magnitude The output always in agreement with constraints imposed by actuators. Then, two finite-time schemes are designed based on derived here and homogeneous method. measurement angular velocity required scheme while it relaxed second one. Finally, effectiveness laws illustrated numerical simulations.

Summary In this paper, the fixed‐time attitude coordination control for multiple rigid spacecraft under an undirected communication graph is investigated. By using backstepping technique, distributed observer, and method of “adding a power integrator,” law designed group spacecraft. The proposed scheme nonsingular can guarantee simultaneously tracking common desired within fixed time even when time‐varying reference available only to subset members. Rigorous analysis provided show that...