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Main Authors: Wang, Yikai, Leng, Tingxuan, Lin, Changyi, Liu, Shiqi, Simon, Shir, Chen, Bingqing, Francis, Jonathan, Zhao, Ding
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.11143
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author Wang, Yikai
Leng, Tingxuan
Lin, Changyi
Liu, Shiqi
Simon, Shir
Chen, Bingqing
Francis, Jonathan
Zhao, Ding
author_facet Wang, Yikai
Leng, Tingxuan
Lin, Changyi
Liu, Shiqi
Simon, Shir
Chen, Bingqing
Francis, Jonathan
Zhao, Ding
contents Humanoid locomotion has advanced rapidly with deep reinforcement learning (DRL), enabling robust feet-based traversal over uneven terrain. Yet platforms beyond leg length remain largely out of reach because current RL training paradigms often converge to jumping-like solutions that are high-impact, torque-limited, and unsafe for real-world deployment. To address this gap, we propose APEX, a system for perceptive, climbing-based high-platform traversal that composes terrain-conditioned behaviors: climb-up and climb-down at vertical edges, walking or crawling on the platform, and stand-up and lie-down for posture reconfiguration. Central to our approach is a generalized ratchet progress reward for learning contact-rich, goal-reaching maneuvers. It tracks the best-so-far task progress and penalizes non-improving steps, providing dense yet velocity-free supervision that enables efficient exploration under strong safety regularization. Based on this formulation, we train LiDAR-based full-body maneuver policies and reduce the sim-to-real perception gap through a dual strategy: modeling mapping artifacts during training and applying filtering and inpainting to elevation maps during deployment. Finally, we distill all six skills into a single policy that autonomously selects behaviors and transitions based on local geometry and commands. Experiments on a 29-DoF Unitree G1 humanoid demonstrate zero-shot sim-to-real traversal of 0.8 meter platforms (approximately 114% of leg length), with robust adaptation to platform height and initial pose, as well as smooth and stable multi-skill transitions.
format Preprint
id arxiv_https___arxiv_org_abs_2602_11143
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle APEX: Learning Adaptive High-Platform Traversal for Humanoid Robots
Wang, Yikai
Leng, Tingxuan
Lin, Changyi
Liu, Shiqi
Simon, Shir
Chen, Bingqing
Francis, Jonathan
Zhao, Ding
Robotics
Humanoid locomotion has advanced rapidly with deep reinforcement learning (DRL), enabling robust feet-based traversal over uneven terrain. Yet platforms beyond leg length remain largely out of reach because current RL training paradigms often converge to jumping-like solutions that are high-impact, torque-limited, and unsafe for real-world deployment. To address this gap, we propose APEX, a system for perceptive, climbing-based high-platform traversal that composes terrain-conditioned behaviors: climb-up and climb-down at vertical edges, walking or crawling on the platform, and stand-up and lie-down for posture reconfiguration. Central to our approach is a generalized ratchet progress reward for learning contact-rich, goal-reaching maneuvers. It tracks the best-so-far task progress and penalizes non-improving steps, providing dense yet velocity-free supervision that enables efficient exploration under strong safety regularization. Based on this formulation, we train LiDAR-based full-body maneuver policies and reduce the sim-to-real perception gap through a dual strategy: modeling mapping artifacts during training and applying filtering and inpainting to elevation maps during deployment. Finally, we distill all six skills into a single policy that autonomously selects behaviors and transitions based on local geometry and commands. Experiments on a 29-DoF Unitree G1 humanoid demonstrate zero-shot sim-to-real traversal of 0.8 meter platforms (approximately 114% of leg length), with robust adaptation to platform height and initial pose, as well as smooth and stable multi-skill transitions.
title APEX: Learning Adaptive High-Platform Traversal for Humanoid Robots
topic Robotics
url https://arxiv.org/abs/2602.11143