Zehfroosh, AshkanTanner, Herbert G.2022-06-092022-06-092022-03-09Zehfroosh, Ashkan, and Herbert G. Tanner. 2022. “A Hybrid PAC Reinforcement Learning Algorithm for Human-Robot Interaction.” Frontiers in Robotics and AI 9 (March): 797213. https://doi.org/10.3389/frobt.2022.797213.2296-9144https://udspace.udel.edu/handle/19716/30973This article was originally published in Frontiers in Robotics and AI. The version of record is available at: https://doi.org/10.3389/frobt.2022.797213This paper offers a new hybrid probably approximately correct (PAC) reinforcement learning (RL) algorithm for Markov decision processes (MDPs) that intelligently maintains favorable features of both model-based and model-free methodologies. The designed algorithm, referred to as the Dyna-Delayed Q-learning (DDQ) algorithm, combines model-free Delayed Q-learning and model-based R-max algorithms while outperforming both in most cases. The paper includes a PAC analysis of the DDQ algorithm and a derivation of its sample complexity. Numerical results are provided to support the claim regarding the new algorithm’s sample efficiency compared to its parents as well as the best known PAC model-free and model-based algorithms in application. A real-world experimental implementation of DDQ in the context of pediatric motor rehabilitation facilitated by infant-robot interaction highlights the potential benefits of the reported method.en-USreinforcement learningprobably approximately correctmarkov decision processhuman-robot interactionsample complexityArticle