Jun 23, 2026 · cs.ROJ/K move · Enter open · S save
Yunsoo Seo, Sol Choi, Euncheol Im, Myo Taeg Lim+1
Center for Humanoid Research, Korea Institute of Science and Technology (KIST), 02792 Seoul, South Korea · University of Texas at Austin, Austin, Texas 78712, USA · Department of Mechanical Engineering, Yonsei University, 03722, Seoul, South Korea · School of Electrical Engineering, Korea University, 02841 Seoul, South Korea
Humanoid robots require whole-body controllers that are both robust and precise in contact-rich environments. While deep reinforcement learning (RL) achieves robust stability, its behavior is tightly coupled to the training objective and command interface, making it difficult to add new feedback objectives without retraining. In this study, we propose an RL guided whole-body model predictive path integral (MPPI) framework that acts as an add-on feedback controller on top of a pretrained RL policy. Instead of using RL policy as the final controller, we use it as a sampling prior that biases MPPI rollouts toward dynamically feasible behaviors. Task objectives are specified through modular MPPI cost terms, and MPPI closes the loop by continuously correcting the RL prior online to satisfy these objectives without retraining the policy. Simulations on a 29-DoF Unitree G1 humanoid in MuJoCo demonstrate stable high-rate control (average 280~Hz). The proposed method improves task-level precision over a pure RL baseline under the same command interface. This is achieved by correcting systematic drift during straight walking and tracking additional whole-body reference signals imposed through the cost.