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Quadruped Robot Solo8 v2

The Solo8 v2 is a lightweight 8-degree-of-freedom quadruped robot with torque-controlled actuators, featuring a weight-reduced body structure and updated electronics.

Overview

Degrees of Freedom

8 DOF - 2 actuated joints per leg (Hip FE and Knee)

Weight

1.9kg (1.7kg robot + 0.2kg battery placeholder)

Communication

Power and communication over wire (24V / Ethernet)

Electronics

Master board v2, micro drivers, and IMU

Key Specifications

SpecificationValue
Degrees of Freedom8 DOF (2 per leg)
Robot Weight1.7kg
Weight with Battery Placeholders1.9kg
Body Structure Weight247g
Leg Configuration4x 2DOF legs
Power Supply24V over wire
CommunicationEthernet

Mechanical Design

Body Structure

The Solo8 v2 features a weight-reduced body frame structure constructed from 3D printed components:
  • Body Structure Bottom: 38g
  • Body Structure Front/Back Plates: 24g each (identical)
  • Body Structure Side Plates: 52g each (identical)
  • Body Structure Top: 35g
  • Total Body Weight: 247g
The body structure is designed to house all electronics while maintaining minimal weight. Multiple top plate options are available:
  • Standard top plate (35g)
  • Top plate with Vicon marker attachments (37g)
  • Top plate with roll bars for marker protection (55g)

Leg Modules

Each leg uses a 2DOF configuration:
  • Hip Flexion/Extension (FE) joint
  • Knee joint
Four identical 2DOF leg modules attach to the body structure. Actuator Module Wire Lengths:
  • Hip FE Motor Phases: 6cm
  • Hip FE Encoder Wire: 10cm
  • Knee Motor Phases: 12cm
  • Knee Encoder Wire: 19cm

Electronics System

Master Board v2

Master Board

Custom electronics board for robot control and communication

Micro Driver Electronics

The Solo8 v2 uses 4 Micro Driver v2 boards:
  • Each board controls 2 brushless motors
  • 2-card stack in front of robot (32g total)
  • 2-card stack in back of robot (32g total)
  • Total micro driver weight: 64g
See Micro Driver Board Documentation for details.

Inertia Measurement Unit

Lord Microstrain 3DM-CX5-25
  • Weight: 13g
  • Extended measurement range:
    • Gyro Rate: ±900 deg/sec
    • Accelerometer range: ±20G
  • Product Page
IMU Origin Position (in robot coordinate system):
  • X: -10.18mm
  • Y: -38.35mm
  • Z: -7.85mm

Wiring Configuration

SPI Wires

Wire IDLengthConnection
#016cmFLHFE and FLK
#116cmFRHFE and FRK
#220cmHLHFE and HLK
#314cmHRHFE and HRK

Micro Driver Wires

  • 24x motor phase wires (7cm each)
For complete wiring details, see the Electronics Wiring Guide.

Assembly Components

3D Printed Parts

All parts should be printed in the positive Z direction of the STL files.

Body Structure Bottom

Weight: 38g

Body Structure Front/Back

Weight: 24g each (2 required)

Body Structure Sides

Weight: 52g each (2 required)

Body Structure Top

Weight: 35g (multiple options available)

Hardware Requirements

Fasteners:
  • 25x M3x8 Socket Head Cap Screws (body structure)
  • 8x M3x12 Socket Head Cap Screws (legs to front plate)
  • 8x M2.5x20 Socket Head Cap Screws (micro driver electronics)
  • 3x M2x6 Socket Head Cap Screws (master board)
  • 3x M2.5x16 Slotted Screws - Polyamide (IMU)
Helicoil Threaded Inserts:
  • 25x M3x4.5 Helicoil
  • 8x M3x6 Helicoil

Bill of Materials

ComponentQuantityNotes
2DOF Leg Modules4Custom assembly
Master Board v21Custom electronics
Micro Driver Board v24Custom electronics
IMU (3DM-CX5-25)1Extended measurement range
Body Structure 3D Printed Parts1 setSee part list above
FastenersVariousStainless steel
Helicoil Inserts33M3x4.5 and M3x6

Coordinate System

The robot coordinate system origin is located at the geometric center of the body structure. The IMU sensor origin is offset from the robot origin as specified in the IMU section above.

Applications

The Solo8 v2 is designed for:
  • Quadrupedal locomotion research
  • Dynamic movement studies
  • Machine learning experiments
  • Agile robot control development

2DOF Leg Assembly

Build instructions for the leg modules

Electronics Wiring

Complete wiring guide and schematics

Master Board

Master board documentation and firmware

CAD Model

Interactive 3D CAD viewer

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