On novel adaptive saturated deployment control of tethered satellite system with guaranteed output tracking prescribed performance

In this paper, a novel model-free adaptive saturated control approach for deployment of the tethered satellite system (TSS) is developed based on time- and event-triggered mechanisms with consideration of the tether length constraint, actuator saturation and unknown external disturbance. Firstly, an appropriate output prescribed performance function is selected to quantitatively analyze the transient and steady-state performance of the deployment control system. Then, a strict-feedback system is established via an output transformation based on which two new model-free adaptive saturated control schemes are developed. Compared with the existing works, the primary advantage of the proposed approach is that the output tracking performance of the TSS can be guaranteed a priori with excellent disturbance rejection capability. Meanwhile, it is the first time that the event-triggered prescribed performance control scheme is proposed both in theoretic and application views, which dramatically reduces the frequency of controller updating and makes the corresponding designed schemes more applicable in practice. Finally, two group of illustrative examples are employed to validate the effectiveness of the proposed control approach.