Event-driven appointed-time neuroadaptive control for combined spacecraft attitude tracking under communication and input constraints

This paper investigates a novel adaptive event-triggered neural-network-based control scheme with an appointed-time prescribed performance function (ATPPF) for attitude tracking of post-capture combined spacecraft with limited communication resources in the presence of unknown inertial parameters, actuator saturation and faults, denial of service (DoS) attack and exogenous space disturbance. A smooth ATPPF is proposed in the control scheme to relax performance constraints considering the DoS attack in the communication network. And the communication network only sends the sampling state at the event-triggered instant to the control module, which can significantly save communication and computation resources. The lumped disturbances and the system uncertainties are compensated only using two adaptive parameters in the controller with the assistance of neural network approximation technology. In this way, the identification of inertial parameters is completely avoided, and the complexity of the controller is reduced. Moreover, the overshoot caused by a communication attack is attenuated with the help of the event-triggering information at the attack start/stop instant. Analyzing stability based on Lyapunov theory, the attitude tracking errors evolve strictly within ATPPF, and all closed-loop states are uniformly ultimately bounded. In addition, the controller design ensures no Zeno behavior. Finally, compared with advanced works, the simulation results show the effectiveness of the proposed control method.