HAFO: Humanoid Force-Adaptive Control for Intense External Force Interaction Environments

Chenhui Dong1, HaoZhe Xu1, Wenhao Feng1, Zhipeng Wang1, 2†, Yanmin Zhou1, 2, Yifei Zhao1, Bin He1, 2,
1Tongji University, 2Shanghai AI Laboratory,
†Corresponding Author

Whole-body control under loads

(Played at the original speed)

Locomotion under two-hand pot load

Locomotion under single-hand case load

Whole-body control under sandbag load

Locomotion under water bottle load

Robust Locomotion To Any Upper-Body Intervention

(Played at the original speed)

Arm-Swing & Dance

Continuous Arm Motion

Stable control under suspension

(Played at the original speed)

Comparison Experiment (Baseline)

Comparison Experiment (HAFO)

Policy deployment from a rope-suspended state

Wave greeting under Suspension

Human-Robot Interaction Force Adaptation Test

(Played at the original speed)

Carrying robot up high steps

Abstract

Reinforcement learning controllers have made impressive progress in humanoid locomotion and light load manipulation. However, achieving robust and precise motion with strong force interaction remains a significant challenge.

Based on the above limitations, this paper proposes HAFO, a dual-agent reinforcement learning control framework that simultaneously optimizes both a robust locomotion strategy and a precise upper-body manipulation strategy through coupled training under external force interaction environments. Simultaneously, we explicitly model the external pulling disturbances through a spring-damper system and achieve fine-grained force control by manipulating the virtual spring. During this process, the reinforcement-learning policy spontaneously generates disturbance-rejection response by exploiting environmental feedback. Moreover, HAFO employs an asymmetric Actor-Critic framework in which the Critic-network access to privileged spring-damping forces guides the actor-network to learn a generalizable, robust policy for resisting external disturbances.

The experimental results demonstrate that HAFO achieves stable control of humanoid robot under various strong force interactions, showing remarkable performance in load tasks and ensuring stable robot operation under rope tension disturbances. Project website: hafo-robot.github.io.

Learning Framework For Humanoid Force-Adaptive Control

Interpolate start reference image.

HAFO Overview. (a) Policy training. A dual-agent strategy with decoupled upper and lower bodies is adopted, where the lower-body policy takes root linear and angular velocities as command inputs, and the upper-body policy uses reference joint trajectories as command inputs. Meanwhile, various explicit dynamic perturbations are introduced at key locations to enhance the system's robustness and adaptability. (b) Strategy deployment. A humanoid robot control system based on teleoperation is developed, employing an efficient inverse kinematics algorithm to compute the robot's joint angles in real time with high precision, enabling efficient loco-manipulation tasks.