Collision-Inclusive Trajectory Optimization for Free-Flying Spacecraft

Collisions may be harnessed as a way to improve the overall safety and navigational effectiveness of some spacecraft. However, leveraging this capability in autonomous platforms requires the ability to plan trajectories comprising impulsive contact. This paper addresses this problem through the development of a collision-inclusive approach to optimal trajectory planning for a three-degree-of-freedom free-flying spacecraft. First, experimental data are used to formulate a physically realistic collision model for the spacecraft. It is shown that this model is linear over the expected operational range, enabling a piecewise affine representation of the full hybrid vehicle dynamics. Next, the dynamics model and vehicle constraints are incorporated into a mixed integer program. Experimental comparisons of trajectories with and without collision-avoidance requirements demonstrate the capability of the collision-inclusive strategy to achieve significant performance improvements in realistic scenarios. A simulated case study illustrates the potential for this approach to find damage-mitigating paths in online implementations.