A single humanoid robot can now skate on wheels, climb stairs, and transform its body shape to handle different delivery tasks.
April 24, 2026
Original Paper
X2-N: A Transformable Wheel-legged Humanoid Robot with Dual-mode Locomotion and Manipulation
arXiv · 2604.21541
The Takeaway
The X2-N robot uses a unified control framework to switch between walking like a human and rolling like a vehicle. This dual-mode locomotion allows it to cover long distances with the efficiency of wheels while still navigating tight indoor spaces. Most robots are specialized for either speed or versatility, but this machine bridges that gap with a high-degree-of-freedom design. A single reinforcement learning policy handles all these complex transitions without needing separate programs for each mode. This design could finally make multi-purpose home and warehouse robots practical for everyday use. It solves the efficiency problem that has held back walking robots for decades.
From the abstract
Wheel-legged robots combine the efficiency of wheeled locomotion with the versatility of legged systems, enabling rapid traversal over both continuous and discrete terrains. However, conventional designs typically employ fixed wheels as feet and limited degrees of freedom (DoFs) at the hips, resulting in reduced stability and mobility during legged locomotion compared to humanoids with flat feet. In addition, most existing platforms lack a full upper body with arms, which limits their ability to