Acrobatic four-legged robot can run at speeds of up to 5m/s
6 August 2025 
The Chinese robot developer Unitree has announced a four-legged robot that can carry loads of up to 25kg, and move at speeds of up to 5m/s (18km/h) – three times faster than Boston Dynamics’ rival Spot quadruped robot, which can handle loads up to 14kg.
A video of the A2 Stellar Explorer robot shows it performing acrobatics, running up and down steps and steep hills with loose surfaces, climbing 1m-high blocks, crashing through a glass window, navigating through complex terrains, carrying a 30kg weight for 12.55km, and supporting the weight of a person jumping up and down on its back.
The robot’s 12 joints are powered by permanent magnet synchronous motors with high-speed inner rotors, that can each deliver 180Nm of torque. It weighs around 37kg – about 6kg of that being a hot-swappable 453Wh battery. It can accommodate two batteries simultaneously.
Carrying a 25kg load, the aluminium-and-plastic robot can walk continuously for more than three hours, covering a distance of around 12.5km. Unloaded, it can walk for more than five hours, covering around 20km. It can handle slopes of up to 45 degrees, and steps up to 30cm high.
When stationary, the robot can support loads of up to 100kg.
The IP56-protected A2 carries one or two Lidar sensors (front and rear) and an HD camera. Unitree claims that it has no blind spots. The robot’s joints incorporate dual encoders and industrial crossed roller bearings
An optional wheeled version will be available.
