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ASTRA

An open-source 9.5 kg quadruped robot with a 3-DoF active spine, designed to be rebuilt for around €1500 and used to study active spine control.

  • Quadruped
  • Open source
  • ROS 2
  • 3D printable

Suggested by Robotheca, created by @fedecomi04 (opens in a new tab), from github.com/fedecomi04/opensource-spinal-quadruped (opens in a new tab). Pinned to commit 41dab01 (opens in a new tab).

Fork on GitHub (opens in a new tab)Download the files at this commit (.zip)
Hardware license
Apache-2.0 (opens in a new tab)
Software license
Apache-2.0 (opens in a new tab)
Commercial use
Allowed

Photo and 3D model

ASTRA, photo from its repository
Photo:@fedecomi04 (opens in a new tab)Apache-2.0source file (opens in a new tab)

3D preview converted from github.com/fedecomi04/opensource-spinal-quadruped at 41dab01, under Apache-2.0. View the original files from GitHub (24.6 MB) (opens in a new tab)

Degrees of freedom
15
Power
24 V
Height
435 mm
Weight
9.5 kg

What it can do

Written by Robotheca from the project's documents.

  • Balances its body horizontally on an inclined plane by actively rotating a 3-DoF spine, keeping either the front or rear body level.
  • Performs a hard-coded trot gait with quintic foot trajectories and inverse kinematics, reaching about 4 cm/s on hardware.
  • Allows single-motor command for hardware bring-up and boot-time joint zeroing.
  • Can be run in a MuJoCo simulation that exposes the same ROS 2 topics as the real hardware.

Bill of materials

This repository has no parts list Robotheca can read yet.

Build guide

The creator's steps, each with its instructions.

  1. 1Order the motors
  2. 2Cut the CFRP frame and leg parts from the STEP file
  3. 33D-print the Tough PLA brackets
  4. 4Wire the electronics
  5. 5Flash the firmware
  6. 6Set up the Pi with ROS 2 Jazzy
  7. 7Bring-up: zero joints, verify in MuJoCo, then walk with the trot controller

The guide appears here as you scroll.

Guide by @fedecomi04 (README.md), under Apache-2.0.

Wiring and electronics

Notes written by Robotheca from the project's documents.

Main parts

  • Raspberry Pi 5 acting as the non-real-time controller running ROS 2 Jazzy.
  • Two STM32H723VG boards handling the real-time CAN-FD bus, one per body half.
  • 15 Damiao motors (DM6006 for hips, waist and knees; DM4010 for the spine) with on-board BLDC drivers.
  • RoboMaster PDU distributing 24 V from a 6S LiPo battery to the motors.
  • A separate power bank supplying the Raspberry Pi.
  • An IMU providing pitch data.

Connections

  • Raspberry Pi 5 connects to each STM32H723VG board over USB.
  • Each STM32 board drives its motors over CAN-FD using FDCAN peripherals, at 1 Mbit/s arbitration and 5 Mbit/s data.
  • Front STM32 board drives the front right and front left motors plus a motor bus; rear board drives rear motors and the spine.
  • The motors receive 24 V from the PDU, while the Raspberry Pi runs from its own power bank so a kill-switch can cut motor power alone.
  • Each 14-byte USB packet from the Pi is unpacked into a CAN frame, and CAN replies are repacked into USB packets for the Pi.