Sampling-based 3-D line-of-sight PWA model predictive control for autonomous rendezvous and docking with a tumbling target

This article introduces a line-of-sight (LOS)-Euler rendezvous and docking (RVD) framework to dock with a tumbling target under several RVD constraints. By a double-loop control scheme, the chaser's position is controlled to track the target's docking port which is coupled with its rotation. The chaser's attitude is driven to track the target's rotation, while satisfying the field of view constraintwhich is coupled with the LOS range. These complex couplings are linearly described in the proposed framework. To this end, the 6 DoF information interactions among the sensor measurements, states, and RVD constraints need no transformation and linearization. Consider the online piecewise affine (PWA) model predictive controller (MPC) may be unsolvable under complex constraints, which is caused by the accumulated prediction error, a sampling-based method is proposed. The linear predictions are driven to the closer neighborhoods of the actual nonlinear states by constructing directional sampling intervals. Besides, a singularity free strategy is provided to realize continuous tracking with crossing the singularities of angle states. Detailed numerical simulations illustrate the validity of the proposed methods.