Model-Based Reinforcement Learning via Stochastic Hybrid Models

Autor: Hany Abdulsamad, Jan Peters
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: IEEE Open Journal of Control Systems, Vol 2, Pp 155-170 (2023)
Druh dokumentu: article
ISSN: 2694-085X
DOI: 10.1109/OJCSYS.2023.3277308
Popis: Optimal control of general nonlinear systems is a central challenge in automation. Enabled by powerful function approximators, data-driven approaches to control have recently successfully tackled challenging applications. However, such methods often obscure the structure of dynamics and control behind black-box over-parameterized representations, thus limiting our ability to understand closed-loop behavior. This article adopts a hybrid-system view of nonlinear modeling and control that lends an explicit hierarchical structure to the problem and breaks down complex dynamics into simpler localized units. We consider a sequence modeling paradigm that captures the temporal structure of the data and derive an expectation-maximization (EM) algorithm that automatically decomposes nonlinear dynamics into stochastic piecewise affine models with nonlinear transition boundaries. Furthermore, we show that these time-series models naturally admit a closed-loop extension that we use to extract local polynomial feedback controllers from nonlinear experts via behavioral cloning. Finally, we introduce a novel hybrid relative entropy policy search (Hb-REPS) technique that incorporates the hierarchical nature of hybrid models and optimizes a set of time-invariant piecewise feedback controllers derived from a piecewise polynomial approximation of a global state-value function.
Databáze: Directory of Open Access Journals