Distributed and Reliable Output Feedback Control of Spacecraft Formation With Velocity Constraints and Time Delays

This article studies the reliable and coordinated control problem of formation flying spacecraft without velocity measurement. External disturbances and directed communication topology, which explicitly has bounded communication delays, are considered. A novel observer is preliminarily designed to ensure a precise and fast estimation of immeasurable velocity. A virtual velocity input is then synthesized for the kinematics. In accordance, a finite-time and velocity-free controller is finally developed for the dynamics with the virtual velocity precisely followed after a finite time. The velocity-free control strategy can ensure the formation spacecraft to follow their desired relative trajectories in a coordinated manner. Numerical simulation is also conducted to validate the performance of the designed scheme.