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Combining model-based controller and ML advice via convex reparameterization
Proceedings of the 6th Annual Learning for Dynamics & Control Conference, PMLR 242:679-693, 2024.
Abstract
Machine Learning (ML) based control, particularly Reinforcement Learning (RL), has achieved impressive advancements but is often black-box and lacks worst-case guarantees in safety-critical systems. In contrast, classical model-based control offers stability guarantees but usually underperforms the machine-learned black-box controller. This motivates us to combine machine-learned black-box and model-based controllers. Due to the nonconvexity of the space of stable controllers, a simple convex combination of the two controllers can lead to instability. We propose using Disturbance Response Control (DRC) to reparameterize the two controllers, ensuring the convexity of the stable controller space. We then propose lambdaCLEAC, which adaptively combines the machine-learned black-box controller and the model-based controller in the DRC parameterization. We prove that our approach achieves the best of both worlds: stability as in model-based control and similar regret bounds as the machine-learned controller.