Bio-Inspired Robotic Finger Looks, Feels, and Works Like the Real Thing

Erik Engeberg, an assistant professor at Florida Atlantic University, has developed and tested a robotic finger using shape memory alloy (SMA), a 3D CAD model of a human finger, a 3D printer, and a unique thermal training technique. Engeberg and his team used a resistive heating process called Joule heating, which involves the passage of electric currents through a conductor that releases heat. They used a 3D CAD model of a human finger to create a solid model of the finger. With a 3D printer, they created the inner and outer molds that housed a flexor and extensor actuator and a position sensor. The extensor actuator takes a straight shape when it's heated, and the flexor actuator takes a curved shape when heated. The team used SMA plates and a multi-stage casting process to assemble the finger. An electrical chassis was designed to allow electric currents to flow through each SMA actuator. Its U-shaped design directed the electric current to flow the SMAs to an electric power source at the base of the finger. This new technology used both a heating and then a cooling process to operate the robotic finger. As the actuator cooled, the material relaxed slightly.