Large-scale spacecraft swarm decentralized formation flying control based on sliding mode control and tracking differentiator

Spacecraft swarm poses great advantages in various fields that are rapidly evolving with the demands for fulfilling multi-purpose space exploration missions, such as flight observations, environmental awareness, and data transmission. Based on the theory of artificial potential field and sliding mode control method, a new distributed autonomous control method for spacecraft swarm formation flying is developed. Inspired by the dynamic system theory, artificial potential velocity field of the spacecraft swarm is designed by using the nonlinear bifurcation theory to generate desired motion path. Different static configuration can be realized, such as circle, concentric double circle and disc. The artificial velocity field is mainly used to generate the velocity command, which can set planning path in real time. Each agent in the swarm can be drove to reach some corresponding desired position without external command, which greatly reduces the complexity of the planning algorithm. Adaptive sliding mode control is used to ensure the precise tracking control for members and system robustness to eliminate external disturbance and uncertainties. A unique tracking differentiator algorithm can generate the relative velocity signals from the measured relative position signals, which are necessary in the artificial velocity field command tracking control. Numerical simulations are presented to show the feasibility of the proposed control strategy, which can achieve various desired swarm formation flying configurations and accomplish formation capture, maintenance and reconstruction successfully.