Overview
BrainCo Revo 3 dexterous hand is designed for industrial automation, research, and robotic manipulation scenarios. It integrates 21 independent motors with 21 active degrees of freedom in a compact bionic form factor. The system supports RS485 communication at a default baud rate of 5 Mbps and CAN FD (in development) communication. Cross-platform C/C++ and Python SDKs are provided for Linux, macOS, and Windows.
Product Features
- 21 DoF Fully Active Bionic Configuration: Integrates 21 independent motors for opposition, lateral abduction/adduction, and bionic finger motion. It supports multi-pose grasping, back-drivable joints, and joint-level control.
- Tactile Feedback: Selected configurations include a distributed tactile array for contact state sensing, which can be used for grasping fragile, soft, and irregular objects.
- Reliability & Environment Testing: Joint flexing lifetime exceeds 1,000,000 cycles. The device has been tested for drop collision, vibration, static pressure, high/low temperature operation, and salt spray.
- SDK & Robotics Ecosystem: Provides C/C++ and Python SDKs, ROS support, and open-source demos for robot application integration and model transfer.
Product Dimensions
Product Parameters
Standard styles: Bionic Silver (supporting Left/Right hands laterality, customizable in bulk)| Category | Parameter | Revo3 U21 | Revo3 U21T | Revo3 U21VT |
|---|---|---|---|---|
| Degrees of Freedom | Total DoF | 21 (Fully direct-drive backdrivable) | 21 (Fully direct-drive backdrivable) | 21 (Fully direct-drive backdrivable) |
| DoF Distribution | 4 fingers 4×4 DoFs, Thumb 5 DoFs | 4 fingers 4×4 DoFs, Thumb 5 DoFs | 4 fingers 4×4 DoFs, Thumb 5 DoFs | |
| Dimensions | Hand Dimensions | 216×108×50 mm | 216×108×50 mm | 216×108×50 mm |
| Operating Parameters | Supply Voltage | 16–85 V | 16–85 V | 16–85 V |
| Max Current | 10 A (24V) | 10 A (24V) | 10 A (24V) | |
| Max Active Grip Force | ≥100 N | ≥100 N | ≥100 N | |
| Max Fingertip Pinch Force | ≥25 N | ≥25 N | ≥25 N | |
| Total Hand Payload | 20 kg | 20 kg | 20 kg | |
| Four-finger Payload | 5 kg | 5 kg | 5 kg | |
| Repeatability | 0.1° | 0.1° | 0.1° | |
| Joint Open/Close Time | 0.33 s | 0.33 s | 0.33 s | |
| Motion Capabilities | Motion Ability | Kapandji opposition test perfect score Covers 33 grasp taxonomies (Feix, GRASP, Taxonomy) | Kapandji opposition test perfect score Covers 33 grasp taxonomies (Feix, GRASP, Taxonomy) | Kapandji opposition test perfect score Covers 33 grasp taxonomies (Feix, GRASP, Taxonomy) |
| Min Grasping Diameter | 10 mm | 10 mm | 10 mm | |
| Max Grasping Diameter | 150 mm | 150 mm | 150 mm | |
| Hardware Configuration | Comm Interface | EtherCAT / CANfd / RS-485 | EtherCAT / CANfd / RS-485 | EtherCAT / CANfd / RS-485 |
| Comm Frequency | 500 Hz | 500 Hz | 500 Hz | |
| Sensors | IMU (Mainboard), Temperature (Mainboard) | IMU (Mainboard), Temperature (Mainboard) | IMU (Mainboard), Temperature (Mainboard) | |
| Control Modes | Position Control, MIT Force/Position, Current Control, Admittance Control, Impedance Control | Position Control, MIT Force/Position, Current Control, Admittance Control, Impedance Control | Position Control, MIT Force/Position, Current Control, Admittance Control, Impedance Control | |
| Tactile Module | Tactile Distribution | / | Full-hand tactile | Full-hand tactile |
| Tactile Type | / | Full-hand piezoresistive array | Full-palm piezoresistive array + Fingertip vision-tactile | |
| Array Taxels | / | 416 | 301 (Piezoresistive) + 2000 (Vision-tactile) | |
| Force Range | / | 0–20 N | 0–20 N | |
| Resolution | / | 0.01 N | 0.01 N |
Note: Stay tuned for more DoF configurations.
Parameter Description
Degrees of Freedom Distribution
Revo 3 features 21 fully active, independently driven degrees of freedom, arranged in a biomimetic joint layout.
| Fingers | Degrees of Freedom | Joint Configuration (Base to Tip) |
|---|---|---|
| Thumb | 5 DoF | CMC Abd Carpometacarpal abduction / adductionCMC Rot Carpometacarpal axial oppositionMCP Flex Metacarpophalangeal flexion / extensionPIP Flex Proximal interphalangeal flexion / extensionDIP Flex Distal interphalangeal flexion / extension |
| Index, Middle, Ring, and Pinky | 4 DoF / finger | Abd Abduction / adductionMCP Flex Metacarpophalangeal flexion / extensionPIP Flex Proximal interphalangeal flexion / extensionDIP Flex Distal interphalangeal flexion / extension |
The thumb supports opposition, pinch, and precision grasping. The other four fingers support independent motion, coordinated grasping, and fine manipulation.
Physical distribution diagram of the 21 fully active independently driven degrees of freedom (motors) of the Revo 3 smart dexterous handJoint Motion Range
The physical achievable joint motion range (corresponding to the physical float parameters in the SDK interface) for each joint is listed in the table below:
| Active Joint | Joint Motion Range | Min Angle | Max Angle |
|---|---|---|---|
| Thumb | CMC Abd (Carpometacarpal Abduction) | 0° | 110° |
| CMC Rot (Carpometacarpal Rotation) | 0° | 105° | |
| MCP Flex (Metacarpophalangeal Flexion) | 0° | 75° | |
| PIP Flex (Proximal Interphalangeal Flexion) | -10° | 90° | |
| DIP Flex (Distal Interphalangeal Flexion) | -20° | 90° | |
| Index | Abd (Abduction/Adduction) | -10° | 30° |
| MCP Flex (Metacarpophalangeal Flexion) | -5° | 90° | |
| PIP Flex (Proximal Interphalangeal Flexion) | -10° | 90° | |
| DIP Flex (Distal Interphalangeal Flexion) | -20° | 90° | |
| Middle | Abd (Abduction/Adduction) | -20° | 25° |
| MCP Flex (Metacarpophalangeal Flexion) | -5° | 90° | |
| PIP Flex (Proximal Interphalangeal Flexion) | -10° | 90° | |
| DIP Flex (Distal Interphalangeal Flexion) | -20° | 90° | |
| Ring | Abd (Abduction/Adduction) | -25° | 20° |
| MCP Flex (Metacarpophalangeal Flexion) | -5° | 90° | |
| PIP Flex (Proximal Interphalangeal Flexion) | -10° | 90° | |
| DIP Flex (Distal Interphalangeal Flexion) | -20° | 90° | |
| Pinky | Abd (Abduction/Adduction) | -30° | 10° |
| MCP Flex (Metacarpophalangeal Flexion) | -5° | 90° | |
| PIP Flex (Proximal Interphalangeal Flexion) | -10° | 90° | |
| DIP Flex (Distal Interphalangeal Flexion) | -20° | 90° |
Control Modes
| Control Mode | Target Parameters | Detailed Description |
|---|---|---|
| Current Mode | Target Current | Current closed-loop control. The controller sets motor output current without position or velocity closed-loop constraints. In this mode, the joints can move passively under external force. It is suitable for compliant interaction, physical teaching, zero-resistance dragging, and adaptive wrapping of flexible objects. |
| Position (Trajectory) Mode | Target Position, Kp, Kd | Position closed-loop control based on trajectory planning. The controller generates acceleration/deceleration trajectories from target positions and uses Kp/Kd parameters to correct position error and reduce oscillation. It is suitable for fixed gesture replay, alignment, and constant-speed motion. |
| MIT Mode | Target Position, Target Velocity, Feedforward Torque, Kp, Kd | Hybrid control using position, velocity, feedforward torque, stiffness, and damping inputs. The controller computes torque from the target state and Kp/Kd parameters. It is suitable for contact interaction, adaptive grasping, manipulation policy testing, and reinforcement learning experiments. |
Note: Stay tuned for more control modes.
Device ID Specifications
In the RS485 bus network topology, the default Left Hand ID for both Revo 2 and Revo 3 dexterous hands is 126, the default Right Hand ID is 127, and the Broadcast ID is 0.
In the network bus topology, developers can configure unique IDs to identify and control the left and right hands separately. Sending instructions to Broadcast ID 0 will control all dexterous hands on the bus simultaneously.
Power-On Reset & Calibration
Power-on self-reset refers to the dexterous hand automatically executing physical position calibration upon power-on. The system will search for the starting position of each finger, and all fingers will open during this period.
⚠️ Critical Safety Notes for Power-On Calibration
- Note 1 (Drop Risk): During the process of position calibration, if the hand is holding any object, there is a potential risk of the object falling.
- Note 2 (Control Prerequisite): After the hand is powered on, a position calibration must be executed once before it can be controlled normally.
Communication Interface
The Revo 3 dexterous hand communicates and is controlled via RS485 and CAN FD (in development) interfaces.
Physical Connector Specifications
| Interface | Connector Model | Description |
|---|---|---|
| 485 | A1257WV-S-2P-6T | RS485 communication interface |
| CAN FD | A1257WV-S-2P-6T | CAN FD communication interface (in development) |
| EtherCAT | A1257WV-S-5P-6T | EtherCAT communication interface |
| VCC | XT30UPB-M | Main power supply interface |
| VBTS | A1257WV-S-10P | Tactile/sensor data transmission expansion interface |
When performing physical wiring and debugging, please pay close attention to the following guidelines:
🔌 Power Supply & Bus Security
- Power Budget: Since the Revo 3 integrates 21 independent motors, instantaneous current can be high under heavy loads or when multiple fingers are gripping. Use a stable 24V DC power supply with a power rating of at least 100W to reduce voltage drop risk.
- Bus Wiring: At 5M baud rate, use shielded twisted pair cables for the RS485 bus and keep the wiring length as short as possible to reduce signal reflection and noise.