James Bruton builds a force-controlled gripper!
In a variety of robotic situations, you’ll need some sort of gripper. In this project, James Bruton attempts to create a force-controlled, three-fingered assembly using an Arduino Uno along with a trio of servos.
Instead of directly controlling the grip fingers, the 3D-printed device is held open with bungee cables. When it’s time to clamp everything down, the servos wind up the cables attached to the inside of the fingers, similar to how human tendons work.
To correlate servo inputs to grip force, he uses a series of springs to allow some amount of compliance, as well as flex sensors attached to the fingers themselves to measure the resulting positions. Arduino code for the build is available here.