Halbach Array Gripper for the 2025 French Robotics Cup

This gripper uses seven small 5mm magnets arranged in a Halbach array to increase magnetic force on one side while canceling it on the other. It is designed for the 2025 French Robotics Cup and has been demonstrated live on my Twitch channel. I am sharing the prototype that helped validate the actuator for our robotics team, Les Karibous.

Feel free to use and adapt it to your needs.

How It Works

The mechanism rotates the magnets using an MG90S servo motor, effectively "activating" or "deactivating" the magnetic grip on metallic objects, such as cans, which are used in the competition.

Note: In the video demonstration, the prototype features nine magnets zone, but the working principle remains identical to the current version with seven magnets.

Required Components

• 1x MG90S servo motor
• 7x 5mm cube magnets
• 4x M3 threaded inserts
• 4x M3 10mm TBHC screws
• 1x M3 16mm TBHC screw
• 2x MF83 bearings
• 2x M2.5 10mm TCHC screws
• 2x M2.5 nuts

Fabrication Notes

• The orange plates are intended to be laser-cut, but for prototyping, they can be 3D printed.
• All other parts are designed to be 3D printed.
• Pay close attention to the orientation of the magnet holder during printing.
• Recommended material: PETG for better durability, but PLA can also be used for testing purposes.

FreeCAD File Available

The FreeCAD design file is provided for reference. However, please note that it was created quickly, meaning it is not parametric, and the functions are not yet optimized.

Important Installation Notes

To ensure proper functionality, the magnets must be arranged in the correct Halbach array configuration, as shown in the reference images.