Smooth and Stable Deployment Control of Tether Satellite System Using Nonlinear Model Predictive Control With Actuator Constraints

This study delves into the control challenges associated with the seamless and stable deployment of a tether satellite system (TSS), while considering various constraints. To realize smooth deployment progress, a feasible region taking into account the actuator constraints and state constraints is proposed. Meanwhile, a nonlinear model predictive control algorithm is integrated to achieve TSS deployment under feasible region constraints by actively regulating the length of the tether. Furthermore, to minimize the disturbances on system states caused by variations in tension, an optimal deployment trajectory is designed using the Gauss pseudospectral method. Then, the precise expression for the terminal region is provided, and by using terminal constraints and Lyapunov theory, the stability of the system is established. Finally, the effectiveness and performance of the proposed nonlinear model predictive controller are demonstrated via numerical case studies.