Adaptive control improves collision avoidance for spacecraft near small bodies
Distributionally Robust Adaptive Iterative Covariance Steering for Small-Body Proximity Operations
Robotics
Summary
Navigating spacecraft close to small objects in space is tricky because gravity and sunlight can push the spacecraft in unexpected ways. The authors combined two techniques to better plan safe paths and automatically adjust control to handle unexpected forces. This approach drastically reduces crashes and near misses during simulations. It means spacecraft can operate more safely and reliably near small space bodies like asteroids or comets.
What this means in practice
- •For spacecraft guidance engineers: Enable reliable autonomous navigation near asteroids by planning risk-aware trajectories that adapt to uncertain forces and model mismatches.
- •For robotic system designers: Improve collision avoidance in robots operating under uncertain force fields by combining adaptive control with robust planning methods.
Authors
Vivek Khatana, Aditya Gahlawat, Naira Hovakimyan, Petros Voulgaris
Abstract
Autonomous small-body proximity operations require continuous-thrust guidance under uncertain gravity, solar-radiation pressure (SRP), and stochastic disturbances. We combine iterative covariance steering (iCS) with $L_1$ distributionally robust adaptive control ($L_1$-DRAC) to provide risk-aware collision avoidance despite mismatch between the nominal planning model and the true dynamics. Iterative covariance steering plans a nominal feedback policy satisfying distributionally robust conditional value-at-risk keep-out constraints, while $L_1$-DRAC compensates for dynamics uncertainty and bounds the residual distributional mismatch through a Wasserstein radius used by the planner. In $\mathbf{1000}$ paired Monte Carlo trials with gravity, SRP, and diffusion mismatch, $L_1$-DRAC adaptive control reduces the keep-out violation rate from $\mathbf{32.7\%}$ to $\mathbf{0.2\%}$ and the physical collision rate from $\mathbf{16.4\%}$ to zero, without actuator saturation.