Qingzhou Lu

Qingzhou Lu, Yao Feng, Baiyu Shi et al.

Humanoid robots are expected to operate in human-centered environments where safe and natural physical interaction is essential. However, most recent reinforcement learning (RL) policies emphasize rigid tracking and suppress external forces. Existing impedance-augmented approaches are typically restricted to base or end-effector control and focus on resisting extreme forces rather than enabling compliance. We introduce GentleHumanoid, a framework that integrates impedance control into a whole-body motion tracking policy to achieve upper-body compliance. At its core is a unified spring-based formulation that models both resistive contacts (restoring forces when pressing against surfaces) and guiding contacts (pushes or pulls sampled from human motion data). This formulation ensures kinematically consistent forces across the shoulder, elbow, and wrist, while exposing the policy to diverse interaction scenarios. Safety is further supported through task-adjustable force thresholds. We evaluate our approach in both simulation and on the Unitree G1 humanoid across tasks requiring different levels of compliance, including gentle hugging, sit-to-stand assistance, and safe object manipulation. Compared to baselines, our policy consistently reduces peak contact forces while maintaining task success, resulting in smoother and more natural interactions. These results highlight a step toward humanoid robots that can safely and effectively collaborate with humans and handle objects in real-world environments.

Botian Xu, Haoyang Weng, Qingzhou Lu et al.

Reinforcement learning (RL) has made significant strides in legged robot control, enabling locomotion across diverse terrains and complex loco-manipulation capabilities. However, the commonly used position or velocity tracking-based objectives are agnostic to forces experienced by the robot, leading to stiff and potentially dangerous behaviors and poor control during forceful interactions. To address this limitation, we present \emph{Force-Adaptive Control via Impedance Reference Tracking} (FACET). Inspired by impedance control, we use RL to train a control policy to imitate a virtual mass-spring-damper system, allowing fine-grained control under external forces by manipulating the virtual spring. In simulation, we demonstrate that our quadruped robot achieves improved robustness to large impulses (up to 200 Ns) and exhibits controllable compliance, achieving an 80% reduction in collision impulse. The policy is deployed to a physical robot to showcase both compliance and the ability to engage with large forces by kinesthetic control and pulling payloads up to 2/3 of its weight. Further extension to a legged loco-manipulator and a humanoid shows the applicability of our method to more complex settings to enable whole-body compliance control. Project Website: https://facet.pages.dev/

Zhongru Zhang, Chenghan Yang, Qingzhou Lu et al.

Video generation models have advanced rapidly and are beginning to show a strong understanding of physical dynamics. In this paper, we investigate how far an advanced video generation model such as Veo-3 can support generalizable robotic manipulation. We first study a zero-shot approach in which Veo-3 predicts future image sequences from current robot observations, while an inverse dynamics model IDM recovers the corresponding robot actions. The IDM is trained solely on random-play data, requiring neither human supervision nor expert demonstrations. The key intuition is that, if a video model can generate physically plausible future motions in image space, an IDM can translate those visual trajectories into executable robot actions. We evaluate this "Veo-3+IDM" approach in both simulation and the real world using a high-dimensional dexterous hand. We find that, owing to the strong generalization capability of frontier video models, Veo-3+IDM can consistently generate approximately correct task-level trajectories. However, its low-level control accuracy remains insufficient to solve most tasks reliably. Motivated by this observation, we develop a hierarchical framework, Veo-Act, which uses Veo-3 as a high-level motion planner and a VLA policy as the low-level executor, significantly improving the instruction-following performance of a state-of-the-art vision-language-action policy. Overall, our results suggest that, as video generation models continue to improve, video models can be a valuable component for generalizable robot learning.