During the Daily Planet program of the Discovery Channel Canada aired on February 18, a robotic hand dexterously rotating two meditation balls caught a lot of viewers’ attention. The amazing innovation is “an underactuated prosthetic hand based on postural synergies” developed by the Rii™ Lab (the Research Laboratory of Robotics Innovation and Intervention) at the UM-SJTU Joint Institute.

Research_Prosthesis2012_5A model of “an underactuated prosthetic hand based on postural synergies”

Because human hands are delicate and deft, it is a challenge to design a prosthetic hand that can replicate motions of human hands. Recent neurology research shows that CNS (Central Nervous System) controls hand muscles in a coordinated manner called a postural synergy, each of which corresponds to flexion/extension actuation statuses of several involved muscles. CNS coordinates postural synergies, adjusting each synergy’s weight (coefficient), to realize various hand motions.
Prof. Kai Xu, Director of the Rii™ Lab, explained that, based on bionic ideas, he designed his prosthetic hand to be a simple and flexible continuum, translating input from two motors globally into 16 joint motions, giving the prosthetic hand the ability to effectively grasp a variety of objects. At the same time, this simple continuum also greatly simplifies the prosthetic design and processing, thereby reducing costs. Coupled with the use of 3D printing technology, it is possible in the future to produce customized, powerful, and cheap prostheses.
Compared to the development results and application of similar robotic hands, to such a compact and flexible design innovation, “Daily Planet” host Dan Riskin could not help but exclaimed: ”Today meditation balls, tomorrow the world!”

“An underactuated prosthetic hand based on postural synergies” on Daily Planet

Background information
“An underactuated prosthetic hand based on postural synergies” is a project developed by the Rii™ Lab (the Research Laboratory of Robotics Innovation and Intervention) at the UM-SJTU Joint Institute. The team is composed of Prof. Kai Xui, Ph.D. students Huan Liu, Zenghui Liu, and master student Yuheng Du.
Project link:http://rii.sjtu.edu.cn/index.php?title=Research_Prosthesis2012