Skip to content
RobothecaBeta
Log in

SoftRobotETF

A low-cost, modular open-source soft robotics platform with tendon-driven continuum robots controlled by force-feedback actuators over serial and I2C.

  • Other
  • Open source
  • arduino
  • 3D printable

Suggested by Robotheca, created by @MilosRasic98 (opens in a new tab), from github.com/MilosRasic98/SoftRobotETF (opens in a new tab). Pinned to commit f07d526 (opens in a new tab).

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

Photo and 3D model

SoftRobotETF, photo from its repository
Photo:@MilosRasic98 (opens in a new tab)MITsource file (opens in a new tab)

3D preview converted from github.com/MilosRasic98/SoftRobotETF at f07d526, under MIT. View the original files from GitHub (13.9 MB) (opens in a new tab)

What it can do

Written by Robotheca from the project's documents.

  • Drives tendon-based soft continuum robots by pulling tendons with actuators that each contain a motor and load cell.
  • Each actuator controls tendon force in closed loop using a PI controller that reads a load cell, with force references set in grams.
  • Actuators can run in manual drive mode, load-cell PI force control mode, or IMU-based PI control mode.
  • Commands use a G-code-like format sent over serial; a controller board relays them to multiple actuators over I2C.
  • Multiple actuators can be daisy-chained and controlled together, and the controller logs actuator and IMU data to CSV.
  • Supports any brushed DC motor up to 28V and 5A by redesigning one 3D-printable part.

Bill of materials

This repository has no parts list Robotheca can read yet.

Build guide

The guide appears here as you scroll.

Guide by @MilosRasic98 (README.md), under MIT.

Wiring and electronics

Notes written by Robotheca from the project's documents.

Main parts

  • Custom actuator PCB built around a Raspberry Pi Pico microcontroller.
  • DRV8842 motor driver for a brushed DC motor.
  • Load cell read through an INA826 instrumentation amplifier, chosen over an HX711 for its higher sample rate.
  • Pololu 12V brushed DC motors with 19:1 gearboxes were used in testing.
  • Robot Controller Raspberry Pi Pico acting as the I2C master for multi-actuator setups.
  • MPU6050 IMU attached to the top of the robot for angle measurement.

Connections

  • Actuators have dual power connectors for daisy-chaining power between units.
  • Actuators have multiple I2C connectors so they can be chained on one I2C bus.
  • In multi-actuator setups, the Robot Controller Pico connects to a computer over USB serial and to the actuators over I2C.
  • The load cell output feeds the INA826 amplifier, whose gain is set by a potentiometer and must be calibrated.