OpenBionics | NTUA – Anthropomorphic, Light-Weight, Affordable Prosthetic Hands

Year: 2015

Groups: OpenBionics, NTUA

Hand Type: Robot Hand

Weight: < 300 gr

Cost: < 200$

Maximum Fingertip Force: 8 N

Time of Closure (from fully closed to fully open): < 1 s

Total fingers: 5

Compliant fingers: yes

Type of motors: Servo Motor

Underactuation: yes

Tendons: yes

Anthropomorphism: yes

Sensory System: no

Number of motors: 1

Number of DoF: 15

Number of fingers: 5

CAD Files: All files required for the replication of the prosthetic hands can be found in the OpenBionics GitHub Repository.


The OpenBionics initiative, prepares and freely distributes open-source designs for the development of anthropomorphic, under-actuated, adaptive, light-weight (weigh less than 300 gr) prosthetic hands of low complexity and cost (cost less than 200$). The proposed hands utilize a novel differential mechanism (a variation of the whiffletree or “seesaw mechanism”) that blocks the motion of the individual fingers, allowing the user to select between 144 grasping postures and gestures using only 1 actuator. Human-likeness of both robot structure and motion is achieved by employing in the design process an index of anthropomorphism. This index utilizes parametric models derived from hand anthropometry studies. The proposed hands can be easily reproduced with off-the-shelf materials and can be fabricated with rapid prototyping techniques (e.g., 3D printers). A prosthetic hand concept, created by the OpenBionics initiative, was appointed first prize winner of the 2015 Robotdalen International Innovation Award, at a prize ceremony held in Västerås, Sweden on September 3rd 2015. More details can be found in the OpenBionics initiative website.

How to cite:

George P. Kontoudis, Minas V. Liarokapis, Agisilaos G. Zisimatos, Christoforos I. Mavrogiannis and Kostas J. Kyriakopoulos, “Open-Source, Anthropomorphic, Underactuated Robot Hands with a Selectively Lockable Differential Mechanism: Towards Affordable Prostheses”, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Hamburg (Germany), 2015.