Kepler K2 Bumblebee

K2 "Bumblebee" is a bright yellow bipedal industrial humanoid from Shanghai's Kepler Robotics. "Bumblebee" is the nickname of the K2 itself, not a separate edition. It combines planetary roller screw linear actuators with rotary actuators, walks with straight knees and has been in mass production since September 2025 at 248,000 yuan per unit.

History and launch

Kepler Robotics was founded in Shanghai in 2023, and the K2 succeeds its K1. First units went to the SAIC-GM plant in Shanghai in April 2025. In September 2025 the company showed a straight-knee gait over bricks, plastic and grass, and later that month announced mass production and customer shipments.

Hardware

The robot stands 1.75 m tall and weighs 75 kg, with a combined dual-arm payload of up to 30 kg. Its distinguishing feature is a hybrid serial-parallel drive: joints use planetary roller screw linear actuators (14 per robot) alongside rotary actuators. Kepler says the screws exceed 80% efficiency and the whole system reaches up to 81.3%, giving about eight hours of operation on a one-hour charge.

The hands have 11 degrees of freedom with fingertip sensors. About 80% of core components, including motors, hands and roller screws, are made in-house; the screws alone account for roughly 20% of the robot's cost.

Software and AI

The gait was trained with reinforcement learning in GPU-accelerated simulation across thousands of parallel instances, plus imitation of human walking such as heel strike and toe-off. A layered VLA+ model handles natural-language commands, with some cognitive functions running in the cloud.

Use cases and deployments

Automotive manufacturing (including SAIC-GM) comes first, followed by logistics, sorting, assembly, guided tours, exhibitions and hazardous work. Kepler reports framework agreements for several thousand units worth hundreds of millions of yuan and estimates a 1.5 to 1.8 year payback for customers, while conceding that large-scale production-line deployment is three to five years away.

Manufacturer

Kepler Robotics is based in Shanghai's Zhangjiang technology hub. Since early 2025 it has closed three funding rounds with strategic investors from precision components, sensors, machine tools and servo systems.

Price and availability

Kepler lists the K2 at 248,000 yuan per unit (reported as roughly $30,000 to $35,000). It has been in mass production and shipping to customers since September 2025.

Timeline

• 2023 Kepler Robotics founded in Shanghai
• 2025-04 First K2 deployment at SAIC-GM
• 2025-09 Straight-knee walking demo and start of mass production

Sources

1. Kepler Announces Mass Production of its K2 "Bumblebee", Humanoid Robotics Technology (2025-09-26)
2. China's humanoid robot achieves human-like straight-knee walk, VnExpress International (2025-09-14)
3. China's humanoid robot start-ups race to scale before Tesla arrives, Jiemian (2025)

Updated: 2026-10-10

Compared with the catalogue

• At 175 cm the Kepler K2 Bumblebee is taller than 68% of the humanoids in the catalogue (median: 170 cm).
• It has 52 degrees of freedom against a catalogue median of 28; more degrees of freedom usually means finer arm and hand movement.
• Its weight of 75 kg (catalogue median: 65 kg) matters for transport and for working around people.
• It is one of 3 Kepler models in the catalogue and one of 128 humanoids from China.

Capabilities