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Quadruped Robot Solo12 (12dof v1)

The Solo12 is a fully-featured 12-degree-of-freedom quadruped robot with torque-controlled actuators. Each leg has 3 active degrees of freedom, enabling complex locomotion behaviors and dynamic maneuvers.

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Overview

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Key Specifications

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Mechanical Design

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Body Structure

The Solo12 body structure (300g) consists of modular 3D printed components: Additional structural components:

• Body Structure Top IMU: 12g
• Body Structure Top Master Board: 11g
• Hip AA Support: 20g each (4 required)
• LED Cover: 0.4g (transparent material)

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3DOF Leg Modules

Each leg features three degrees of freedom:

1. Hip Abduction/Adduction (AA): Lateral leg movement
2. Hip Flexion/Extension (FE): Forward/backward leg movement
3. Knee: Lower leg rotation

Weight per leg: 485g See the 3DOF Leg Documentation for complete details.

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Range of Motion

Hip AA Joint:

• Standard range: 215 degrees
• Extended range: 325 degrees (when Hip FE moves simultaneously)

Hip FE and Knee Joints:

• Multiple rotations possible
• Enables stepping onto obstacles and recovery from falls
• Wire routing through Hip FE joint limits total rotations

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Electronics System

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Master Board v2

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Micro Driver Boards

The Solo12 uses 6 Micro Driver v2 boards organized in two stacks: Front Stack (3 boards):

• Controls front left and front right legs
• Total weight: 47g per stack

Hind Stack (3 boards):

• Controls hind left and hind right legs
• Total weight: 47g per stack

Each board controls 2 brushless motors. See the Micro Driver Documentation for details.

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Motor Assignment

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Inertia Measurement Unit

Lord Microstrain 3DM-CX5-25

• Weight: 13g
• Mounted in front of robot
• Label pointing downward
• Extended measurement range:
  • Gyro Rate: ±900 deg/sec
  • Accelerometer Range: ±20G
• Product Page

IMU Origin Position (in robot coordinate system):

• X: 104.07mm
• Y: -6.35mm
• Z: 15.40mm

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Assembly Components

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Hip AA Bearings

Stainless Steel Bearings ET2520 2Z VA

• Dimensions: 25mm x 20mm x 4mm
• Weight: 3.4g each
• Quantity: 4 required

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Fasteners

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Helicoil Thread Inserts

• M3 x 4.5mm: 32 inserts
• Type: 1.5xD, Böllhoff 41890030045

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Wiring Details

Complete wiring documentation is available in the Electronics Wiring Guide. Key wiring considerations:

• Motor phase wires routed through leg joints
• SPI communication wires to each micro driver stack
• IMU communication wire (4 conductors)
• Power and Ethernet interface wire

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Bill of Materials

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Coordinate System

The robot coordinate system origin is located at the center of the body structure. The IMU coordinate system has the same orientation as the robot coordinate system, with the offset documented above. For complete coordinate system conventions, see Conventions.

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Robot Calibration

A dedicated calibration tool is available for the Solo12. See the Quadruped 12dof Calibration Tool documentation.

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Vicon Object for Motion Capture

Body Structure Center Plate with Vicon Markers

• Weight: 43g
• 13 markers (Ø 9.5mm)
• Can replace standard center plate
• Used for base state estimation

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Solo12 v1.1 - Autonomy Upgrade

The Solo12 v1.1 upgrade enables autonomous operation without tether: Upgraded Components:

• Power System: 2x SLS X-Cube 850mAh LiPo batteries (11.1V, 3S1P)
  • One battery in front, one in back
  • 68g each, 136g total
  • XT30 connectors
  • 30C continuous / 60C burst discharge
• Power Management Board: Custom board for safe operation
  • Battery voltage and current monitoring
  • On/off switch and e-stop handling
  • Emergency power cutoff
  • Inrush current limitation
  • SPI communication with Master Board
  • 8x XT30 output connectors
  • Dimensions: 65mm x 35mm
  • Weight: 16g
• Wireless Communication: WiFi module
  • Replaces wired Ethernet
  • Enables untethered operation
  • Compatible with existing software stack
• LED Status Ring: 12 RGB LEDs
  • Mounted on top of robot
  • Real-time status indication
  • Visible from all angles
• Payload Interfaces: Mounting points for accessories
  • Top and bottom attachment points
  • Standard hole patterns
  • Additional sensors or cameras

Benefits:

• Untethered operation for outdoor experiments
• Onboard IMU-based state estimation
• Operation outside motion capture area
• Longer experiment duration with dual batteries
• Real-time battery monitoring and safety

Weight Breakdown (v1.1):

• Solo12 v1 base: 2.5kg
• Batteries: 136g
• Power board: 16g
• Additional structure: ~148g
• Total: ~2.8kg

See Power Board Documentation for details.

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Applications

The Solo12 is designed for:

• Advanced quadrupedal locomotion research
• Dynamic maneuvers and acrobatic behaviors
• Machine learning and reinforcement learning
• Whole-body control development
• Outdoor terrain navigation (with v1.1 autonomy upgrade)

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Related Resources