Performance-adjustable PPC policies for spacecraft attitude-orbit coupled tracking under event-triggered sampling

This paper investigates a performance-adjustable prescribed performance control (PPC) policy under event-triggered sampling for spacecraft attitude-orbit coupled tracking with consideration of limited communications and performance constraints. Firstly, a logarithmic barrier Lyapunov function is introduced to derive the attitude-orbit coupled tracking controller with guaranteed transient and steady-state behaviors by applying the PPC algorithm. Then, to reduce the burden of the signal transmission under limited communications, the event-triggered mechanism is applied to determine when the above attitude-orbit coupled tracking controller updates. Furthermore, an indirect adaptive method with less computation that does not involve complex regression matrices or neural networks is designed to resist external disturbances. Compared with the traditional spacecraft control policies, the proposed strategy fully considers the state convergence performance, sampling performance, and calculation performance. The proposed one here can arbitrarily adjust the sampling performance and state convergence performance in an excellent trade-off. Finally, a group of illustrative examples is organized to demonstrate the effectiveness of the proposed control policy.