Adaptive dynamic event-triggered deployment control for space triangle tethered formation system with external disturbance

Abstract

Space tethered system has been widely investigated because of its extensive applications in space observation, debris removal, and space solar power station, etc. Yet, due to the system coupling nonlinearities, unknown disturbances, and on-board limited communication constraints, the deployment control of the spacecraft system is still challenging. In this paper, an adaptive integral sliding mode controller is designed by using neural network estimator, barrier function and event-triggered mechanism, which ensures that the system deploys to the specified configuration in finite time. Giving that the lumped disturbances are bounded by an unknown boundary, the gain of the switching term is tuned by the barrier function such that the gain-overestimation problem can be avoided. Then, the dynamic event-triggered mechanism updates the control signal non-periodically between the controller and the actuator, thus communication resources can be saved. Moreover, the stability of the closed system with and without event-triggered mechanism is analyzed. Finally, simulation tests are carried out to exhibit the effectiveness of the proposed control scheme.