Robotic Hands UNITREE G1 Dex3-1 L+R without tactile sensors

UNITREE G1 Dex3-1 robotic hands, left and right

This set includes a left and a right three-fingered robotic hand designed for use with the UNITREE G1 humanoid robot. Each hand has 7 degrees of freedom and uses seven miniature brushless joints with force control. Hybrid force and position control supports precise movement, with fingertip positioning repeatability of ±2 mm. Communication operates at 1,000 Hz via USB 2.0, and extensive feedback data supports complex manipulation and precise monitoring of the mechanism.

Degrees of freedom and movement

Each Dex3-1 hand has three movable fingers: the thumb has 3 degrees of freedom, while the index and middle fingers each have 2. Joint ranges allow a variety of grip configurations. The thumb joints move through -60° to 60°, -35° to 60° and 0° to 100°. The index and middle finger joints each move through 0° to 90° and 0° to 100°, respectively. This arrangement allows the fingers to move in multiple planes and adapt to different tasks. Fingertip positioning repeatability is ±2 mm.

Hybrid force control and joints

The Dex3-1 uses hybrid force and position control, allowing control beyond setting a specific finger position. Each hand has six miniature, directly driven brushless force-control joints and one geared joint. The joint models used are F-1515-108 and F-1515-214. Control parameters include torque, angle, angular velocity, stiffness and damping. For the F-1515-108, theoretical maximum torque is 0.76 Nm; actual torque is 0.49 Nm in the direction of rotation and 1.37 Nm in the opposite direction. For the F-1515-214, theoretical maximum torque is 1.498 Nm; actual torque is 0.86 Nm in the direction of rotation and 3.1 Nm in the opposite direction.

Operational feedback

Feedback data covers the mechanism’s current state, including joint mode, position, velocity, torque and temperature, as well as voltage, current and IMU data. Control feedback also includes joint stiffness and damping coefficients. This information supports monitoring hand behaviour during tasks and using multiple parameters for motion planning and control.

Communication

The hand uses a USB 2.0 interface and communicates at 1,000 Hz. A full data packet is 1,234 bytes for transmission and 1,270 bytes for reception. Joint control also operates at 1,000 Hz, with High Speed Unibus used for joint communication. These specifications support frequent control updates and access to detailed hand-status data during complex motion sequences.

Design for UNITREE G1

Each hand weighs 710 g and measures 175 × 88 × 77 mm when extended. Designed to work with the UNITREE G1 humanoid robot, the Dex3-1 combines a compact form with advanced motion control and feedback for a range of manipulation tasks.

General specifications

• Manufacturer: UNITREE
• Model: DX31-214N
• Compatibility: UNITREE G1

Hand specifications

• Weight: 710 g
• Dimensions: 175 × 88 × 77 mm (extended)
• Degrees of freedom: Thumb ×3; index finger ×2; middle finger ×2
• Drive mechanism: 6 direct-drive motors; 1 gear-driven motor
• Joint range of motion: Thumb joint 0: -60° to 60°; thumb joint 1: -35° to 60°; thumb joint 2: 0° to 100°; index finger joint 0: 0° to 90°; index finger joint 1: 0° to 100°; middle finger joint 0: 0° to 90°; middle finger joint 1: 0° to 100°
• Fingertip positioning repeatability: ±2 mm
• Operating voltage: 12–58 V
• Quiescent current: 0.2 A at 58 V
• Maximum current: 10 A
• Communication interface: USB 2.0
• Operating temperature range: -20°C to 60°C
• Load conditions, palm facing down: At room temperature, gripping a hard round object with a diameter of 5 cm; maximum weight: 500 g; maximum power: 400 W for 3 s
• Load conditions, palm facing left: At room temperature, gripping a hard round object with a diameter of 5 cm; maximum weight: 500 g; maximum power: 400 W for 3 s

Software specifications

• Communication frequency: 1,000 Hz
• Full data packet size: Transmitter: 1,234 bytes; receiver: 1,270 bytes
• Measurement feedback data: Joint mode, joint position, joint speed, joint torque, joint temperature, voltage and current, and IMU data
• Control feedback data: Joint mode, joint position, joint speed, joint torque, joint stiffness coefficient and joint damping coefficient

Miniature brushless force-control joint specifications

• Models: F-1515-108 miniature brushless force-controlled joint; F-1515-214 miniature brushless force-control joint
• Weight: 45 g
• Dimensions: 34.8 × 23.1 × 23.3 mm
• Gear ratio: F-1515-108: 1:108; F-1515-214: 1:214
• Maximum theoretical torque: F-1515-108: 0.76 Nm; F-1515-214: 1.498 Nm
• Maximum actual torque, in the direction of rotation: F-1515-108: 0.49 Nm; F-1515-214: 0.86 Nm
• Maximum actual torque, opposite to the direction of rotation: F-1515-108: 1.37 Nm; F-1515-214: 3.1 Nm
• Maximum rotational speed: F-1515-108: 23 rad/s; F-1515-214: 11 rad/s
• Maximum line current: 4.76 A
• Control communication frequency: 1,000 Hz
• Communication method: High Speed Unibus
• Encoder: Absolute rotor position encoder
• Operating temperature range: -20°C to 60°C
• IP rating: Not specified
• Operating voltage: 12–24 V
• Motor feedback: Torque, angle, angular velocity and temperature
• Motor control commands: Torque, angle, angular velocity, stiffness and damping