China’s humanoid robot Bumblebee now walks with human-like gait

Shanghai Kepler Robotics has unveiled a significant advancement in its humanoid robot K2 “Bumblebee,” showcasing China’s first “hybrid-architecture disturbance-resistant” gait that enables the robot to walk with a natural, human-like straight-knee motion. This breakthrough is achieved through a novel hybrid actuation system combining planetary roller screw linear actuators and rotary actuators in a series-parallel configuration. The linear actuators act as the robot’s primary “leg muscles,” providing walking force, while rotary actuators manage fine adjustments and terrain adaptation. This design offers high energy efficiency (81.3%), precise positioning, and strong load-bearing capacity, allowing Bumblebee to maintain balance over uneven surfaces such as bricks and grass, and to carry payloads up to 30 kilograms (66 pounds). To bridge the gap between simulation and real-world performance, Kepler addressed mechanical and control challenges by integrating reinforcement learning, imitation learning, and torque control, enabling dynamic gait switching and robust stability despite sensor noise, actuator