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This paper presents a parameter governor-based control approach to constrained spacecraft rendezvous and docking (RVD) in the setting of the Two-Body problem with gravitational perturbations. An add-on to the nominal closed-loop system, the Time Shift Governor (TSG) is developed, which provides a time-shifted Chief spacecraft trajectory as a target reference for the Deputy spacecraft, and enforces various constraints during RVD missions, such as Line of Sight cone constraints, total magnitude of thrust limit, relative velocity constraint, and exponential convergence to the target during RVD missions. As the time shift diminishes to zero, the virtual target incrementally aligns with the Chief spacecraft over time. The RVD mission is completed when the Deputy spacecraft achieves the virtual target with zero time shift, which corresponds to the Chief spacecraft. Simulation results for the RVD mission in an elliptic orbit around the Earth are presented to validate the proposed control strategy. 

A parameter governor-based control scheme is developed to enforce various constraints, such as the Line of Sight (LoS) cone angle, the thrust limit, and the relative approach velocity during rendezvous missions in a near rectilinear halo orbit (NRHO) in the Earth-Moon system. The parameter governor is an add-on scheme to the nominal closed-loop system, which dynamically adjusts controller parameters in order to enforce the constraints. For the application to the rendezvous mission, we utilize the Time Shift Governor (TSG) which time shifts the target trajectory commanded to the Deputy spacecraft controller. The time shift is gradually reduced to zero so that the virtual target trajectory gradually converges to the Chief spacecraft trajectory as time evolves, and the rendezvous mission can be accomplished. Simulation results are reported that demonstrate the effectiveness of the proposed control scheme.