5 Degree of Movement Prosthetic Thumb using Twisted Fiber Artificial Muscles

The loss of a hand can be detrimental to an individual’s overall mobility and functionality. Which is why prosthetics have been an important piece of technology and why it’s continuously growing. There are several caveats to current prosthetics including cost, weight, functionality, cosmetics, and overall fluidity of movement. Artificial muscles are a current technology that may  many of these caveats. Artificial muscles can consist of an actuator that under a stimulus can extend, contract, or rotate. This stimulus can consist of temperature, electrochemical, pneumatics, or pressure. This paper focuses on a thermal actuated artificial muscle composed of twisted fibers combined with a conductive material. These artificial muscles are attached to a resin printed skeleton of the thumb that has been modified to house the artificial muscles along with 3D printed flexible ligaments that holds the bones together. The artificial muscles are actuated individually using an Arduino and a power supply to conduct joule heating on the conductive materials to actuate the twisted fibers. The result is a thumb that’s movement mimics that of a human thumb in terms of the 5 degrees of movement found. These movements include flexion, extension, adduction, abduction, and lastly the hardest movement to replicate being opposition. This is the first step in creating a prosthetic that can fully mimic the movement of a human hand while also being affordable and low weight.