Model Predictive Control for Spacecraft Rendezvous and Docking: Strategies for Handling Constraints and Case Studies

TLDR

The paper proposes a strategy and case studies for spacecraft relative motion guidance and control using linear‑quadratic model predictive control with dynamically reconfigurable constraints. The controller switches between MPC guidance for rendezvous and docking, incorporating phase‑specific constraints such as obstacle avoidance, line‑of‑sight cone, bandwidth, and exhaust plume limits, and uses state estimates from relative angle and range measurements to remain robust to estimator dynamics and noise. Simulation studies with a nonlinear spacecraft orbital model demonstrate the effectiveness of the MPC controller.

Abstract

This paper presents a strategy and case studies of spacecraft relative motion guidance and control based on the application of linear quadratic model predictive control (MPC) with dynamically reconfigurable constraints. The controller is designed to transition between the MPC guidance during a spacecraft rendezvous phase and MPC guidance during a spacecraft docking phase, with each phase having distinct requirements, constraints, and sampling rates. Obstacle avoidance is considered in the rendezvous phase, while a line-of-sight cone constraint, bandwidth constraints on the spacecraft attitude control system, and exhaust plume direction constraints are addressed during the docking phase. The MPC controller is demonstrated in simulation studies using a nonlinear model of spacecraft orbital motion. The implementation uses estimates of spacecraft states derived from relative angle and range measurements, and is robust to estimator dynamics and measurement noise.