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The article deals with the use of iterative learning control (ILC) to improve the attitude tracking accuracy of high precision satellite. Topics discussed include the schemes of ILC, such as D type and P type, a description of the rigid satellite attitude tracking error dynamics and ILC design for attitude tracking. Also presented is an example that validates the proposed anticipatory ILC scheme for attitude tracking.

The article discusses a study which examined the attitude stabilization with external disturbance, unknown inertia parameters, and actuator uncertainties as well as fault and misalignment. It proposed an adaptive control to render the closed-loop system input-to-state stable. A mathematical model of a rigid spacecraft is also presented.

The article proposes a decentralized adaptive sliding-mode control law that regulates attitude and angular velocity errors of individual spacecraft with regard to reference commands and reduces relative attitude and angular velocity errors between spacecraft. The proposed law reportedly makes sure that each spacecraft reaches attitude synchronization with other spacecraft in the formation even in the presence of model uncertainties and external disturbances. The design is said to apply to general communication topology.

In this paper, we focus on the design of a fuel-optimal maneuver strategy to reconfigure satellite formation using a low-thrust propulsion system. We cast it as an optimization problem with a desired final satellite formation configuration subject to collision avoidance constraints on the paths of the chief and all deputy satellites. The satellite terminal orbit states corresponding to this desired formation configuration are ensured by imposing an energy-matching condition and final geometry configuration constraints in the problem formulation. In addition, we adopt our recently developed relative satellite kinematics model to accurately describe relative satellite orbit geometry in the presence of J2 effects. The resulting nonlinear optimal control problem is converted into a nonlinear programming problem by the application of the Legendre pseudospectral method and is then solved by using a sparse nonlinear optimization software named TOMLAB/SNOPT. Simulation results demonstrate the efficiency of our proposed method in designing fuel-optimal maneuvers for a wide class of satellite formation problems. [ABSTRACT FROM AUTHOR]

The article focuses on a study which establishes the J2 dynamics of the reference satellite S0 in the local rotating frame. It notes the study's use of two Cartesian coordinate frames. According to the authors, they use the Lagrangian formulation to develop the relative dynamics of the member satellite Sj. The equation for the kinetic energy per unit mass of the satellite Sj is also presented.