A1

Overview

The Unitree A1 is Unitree Robotics' original mass-market research quadruped, the predecessor to the Go1 and Go2 series. It weighs 12 kg, carries 5 kg payload, and stands 400 mm at the hip. The A1 was launched in 2020 and was notable for its price point (under $10,000 for the research variant) relative to Boston Dynamics Spot, making legged robotics research accessible to a much broader range of institutions globally. Official new stock is no longer available, but the platform remains in active use across university research labs worldwide.

The A1 represented Unitree's first serious attempt at a research-grade quadruped combining proprioceptive actuation (joint position, velocity, and torque estimation) with an accessible SDK, establishing the template that the Go2 and B2 series follow.

Key Specifications

• Degrees of freedom: 12
• Payload: 5 kg
• Top speed: 3.3 m/s
• Standing height: 400 mm
• Weight: 12 kg
• Battery runtime: approximately 1 hour
• Software: Unitree Legged SDK (ROS compatible), community maintained

The Unitree Legged SDK provides low-level joint control at 500 Hz, enabling researchers to implement fully custom locomotion controllers in C++ or Python. This level of SDK access is the primary reason the A1 remains relevant as a research platform despite its age.

Use Cases

The A1 is used in locomotion research, terrain traversal studies, reinforcement learning and sim-to-real transfer experiments, and multi-robot co-ordination research. It is a common platform for academic papers on legged robot control, owing to its combination of price, capability, and SDK access. Many significant papers in learning-based quadruped locomotion used A1 hardware, and their codebases often include A1-compatible implementations.

Buying Used

The A1 has a well-established secondhand market driven by university equipment sales and research group upgrades to the Go2 or B2 platforms. UK prices range from £2,500 to £5,000. Battery condition is important; test runtime under a 3 kg payload to confirm the battery retains meaningful capacity. Check all 12 joints for wear, particularly the hip abduction joints. Confirm SDK compatibility with your ROS environment, as some newer ROS2 distributions require updated wrapper packages.

Alternatives to Consider

• Unitree Go2 Pro: Current-generation platform with better sensors, ROS2 support, and active Unitree firmware updates.
• Unitree Go1: Intermediate generation at lower secondhand price with comparable SDK access.
• Deep Robotics Lynx: Higher payload at 5 kg with current software support, at $8,000 new.