A Gear-Based "Antagonistic Variable Stiffness" System Makes This Robot Finger Flexible Yet Tough
Designed to grasp any object yet strong enough to shrug off a blow from a hammer, this 3D-printed finger packs a punch.
Robotics researchers from the Harbin Institute of Technology have come up with what they claim is a better design for a robot's finger — offering the ability to operate in harsh environments and undergo physical impact without failure.
"[Our design] will enable the dexterous hand to have better mechanical robustness," explains corresponding author Yiwei Liu, professor, of the team's work, "thus solving the problem that the rigid driven dexterous hand is easily damaged by physical collisions in unstructured environments."
Where the team's design differs from traditional rigid robotic hands is in the way the finger works. Designed to more closely mimic a human digit, the robotic finger swaps out the typical dual-actuator variable stiffness system for what its creators call an "antagonistic variable stiffness finger mechanism" based on gear transmission, rather than cables. The result: a finger that can adjust its stiffness while also better absorbing the energy of physical impacts without damage.
Compared to the current state of the art, the team claims its finger is simpler, smaller, and lighter — weighing 480g (around 16oz) in prototype form, combining 3D-printed plastic parts with an alloy body and driven by an STMicroelectronics STM32F407 microcontroller. In testing, the prototype proved capable of picking up a range of differing-shape objects, and withstood expected levels of force applied upon it.
"This research is of great importance to improving the manipulation level of dexterous hands in unstructured environments or physical interacting tasks," claims Liu, though without providing a roadmap to commercialization.
The team's work has been published under open-access terms in the journal Frontiers of Mechanical Engineering.