This paper investigates the problem of rotation matrix-based attitude synchronization and tracking control for spacecraft formation flying exposed to external disturbance and unknown inertial matrix. For the purpose of ensuring finite-time convergence for attitude tracking errors, a hyperbolic tangent function-based sliding mode surface is designed. Based on the sliding mode variable, an adaptive law is proposed to estimate the upper bound of unknown disturbance and radial basis function is employed to approximate unknown system dynamics. The minimum learning parameter algorithm is adopted to reduce the computational burden. It is demonstrated by Lyapunov-based analysis that the sliding mode surface and estimating errors will possess finite-time stability under the presented controller. Finally, results of numerical simulations are exhibited to validate the stability and validity of the proposed controller. INDEX TERMS rotation matrix, finite-time coordinate control, spacecraft formation flying, sliding mode, neural network
This paper provides a solution for the trajectory tracking control of a hypersonic flight vehicle (HFV), which is encountered performance constraints, actuator faults, external disturbances, and system uncertainties. For the altitude and velocity control subsystems, the backstepping-based dynamic surface control (DSC) strategy is constructed to guarantee the predefined constraint of tracking errors. The introduction of first-order low-pass filters effectively remedies the problem of “complexity explosion” existing in high-order backstepping design. Simultaneously, radial basis function neural networks (RBFNNs) are adopted for approximating the unavailable dynamics, in which the minimum learning parameter (MLP) algorithm brilliantly alleviates the excessive occupation of the computational resource. Specially, in consideration of the unknown actuator failures, the adaptive signals are designed to enhance the reliability of the closed-loop system. Finally, according to rigorous theoretical analysis and simulation experiment, the stability of the proposed controller is verified, and its superiority is exhibited intuitively.
This paper concerns the control algorithm oriented to nonparallel-ground-track-imaging for agile optical satellite. Firstly, for obtaining the desired trajectory, the mapping relationship between the satellite attitude and the ground stripe is established by using space vector method. According to the mapping function, an attitude adjustment strategy via constant scanning velocity is proposed. Then, considering the exact information of the external disturbance cannot be obtained and the input saturation problem, a robust anti-saturation tracking controller is designed via fixed-time disturbance observer and integral sliding mode. Finally, the effectiveness of the proposed control algorithm is illustrated by numerical simulation. INDEX TERMS Agile optical satellite, nonparallel-ground-track-imaging, integral sliding mode, disturbance observer, input saturation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.