github

Choloepus

Introduction

Choloepus is a flexible gripper driven by a three-phase motor with Field-Oriented Control (FOC).

Performance & Features

• Capable of lifting 3kg of water
• Capable of delicate operations such as picking up a needle or gripping an eggshell (video demo)
• Maximum drive current: 2A
• Drive voltage range: 12V ~ 24V
• Supports three control modes:
  • Force closed-loop (current loop)
  • Position closed-loop
  • Hybrid force-position control
• Weight: 300g

Mechanical Structure

Except for the motor and the depth camera, all other components were designed in-house. They can be fabricated via 3D printing and basic mechanical processing. You can find the models and engineering drawings in the /0.Model directory.

Circuit Design

You can find the circuit schematics and PCB layout in ./Hardware.

Firmware

This project’s firmware is developed with PlatformIO under the Arduino framework.

We have built upon the open-source project SimpleFOC and made optimizations to drive the flexible gripper with FOC control.

The firmware is located in ./2.Frimware.

Communication

At the bottom of Choloepus, there is a 4-PIN XT30 connector that supports a DC input voltage of 12 ~ 24V and CAN bus communication.

In the /3.Software directory, you will find a Python library that lets you create a Choloepus object and establish communication:

my_gripper = gripper(serial_port='COM10', id_num=20)

Choloepus supports different control modes, shown below:

Video Demo

Watch the Demo

This video demonstrates how Choloepus collaborates with a continuum robotic arm designed in our lab to perform a grape suturing operation.

License

Choloepus is released under the AGPL-3.0. For more details, please refer to the LICENSE.

Contact

Feel free to reach out to me at: changxiangchina@outlook.com