Dual-Quaternion-Based Spacecraft Autonomous Rendezvous and Docking Under Six-Degree-of-Freedom Motion Constraints

Abstract

This paper addresses the integrated attitude and position control problem for the final phase proximity operations of spacecraft autonomous rendezvous and docking, in which important motion constraints of the chaser spacecraft are considered. On the one hand, to ensure reliable real-time measurements of the relative attitude and position information between two spacecraft, the relevant sensor system of the chaser spacecraft is required to continuously point toward the target; on the other hand, for the proximity safety concerns, the chaser also needs to follow a specified approach path constraint. A special dual-quaternion-based artificial potential function is presented to encode information regarding these motion constraints. Using this potential function, a novel six-degree-of-freedom control method is proposed to ensure the arrival of the chaser at the docking port of the target with a desired relative attitude, while strictly complying with all constraints. The closed-loop stability is demonstrated by a Lyapunov-based method in conjunction with the special properties of the artificial potential function. The local minimum problem associated with the artificial potential function can be addressed by selection of control parameters that satisfies a mild condition. Simulation results of prototypical spacecraft rendezvous and docking missions are provided to illustrate the effectiveness of the proposed method.