hand comes to life
a European research team has their way it won’t be long before the
sci-fi bionic man becomes reality.
The research team is currently developing a highly dexterous,
bioinspired artificial hand and sensory system that could provide
patients with active feeling.
Funded by the Future and Emerging Technologies initiative of the IST
programme, the Cyberhand project aims to hard-wire a mechanical hand
into the nervous system, allowing sensory feedback from the hand to
reach the brain, and instructions to come from the brain to control the
hand, at least in part.
The research team is coordinated by Professor Paolo Dario with Professor
Maria Chiara Carrozza leading the development of the hand. The project
united researchers from Germany, Spain, Italy and Denmark. To date the
project has made several significant achievements. The project has a
complete, fully sensitised five-fingered hand.
The Cyberhand prototype has 16 Degrees of Freedom made possible by the
work of six tiny motors. Each of the five fingers is articulated and has
one motor dedicated to its joint flexing for autonomous control. It
features that miracle of evolution, the opposable thumb, so the device
can perform different grasping actions.
Other significant achievements include: the design, implementation and
assessment of different types of neural interfaces in order to develop
the bi-directional link between the peripheral nervous system and the
prosthesis; the implementation of an integrated electronic system able
to be connected to the neural interfaces and thus to be implanted
together with the electrodes in the amputee’s residual limb; the
development of the software for the control of the hand using
electroneurographic signals from LIFE (Longitudinal IntraFascicular
In addition to traditional wire LIFEs, used to connect the hand to the
nervous system, a new type of electrode has been developed to improve
performance and make them less invasive in humans: the Thin Film LIFE (tfLIFE).
Taking inspiration from the real hand, where a muscle pulls a tendon
inside a synovial sheath, Cyberhand's finger cables run through a Teflon
sheath pulled by a DC motor. So the proximal, medial and distal
phalanges are all driven by the same tendon. This approach is called
underactuation as there are more Degrees of Freedom than Degrees of
Movement (motors); it means the prosthesis has a self-adaptive grasp.
Dr Lucia Beccai, project manager, explained: “This is a fundamental
feature of the Cyberhand prosthesis because only a limited number of
control signals are available for user’s voluntary control.”
Importantly, it also means less user effort is required to control the
hand during daylong use. Dr Beccai told Middle East Health, the hand
uses two types of senses.
The Cyberhand prototype integrates a proprioceptive artificial sensory
system, in order to integrate the ability to sense both the hand
position and movement, and an exteroceptive artificial sensory system,
in order to sense the tactile stimuli originating from the environment
when the hand grasps and manipulates objects. The link between the hand
and the nervous system is achieved by using electrodes – neural
interfaces – able to record neural signals (to extract voluntary
commands to control the prosthesis) and to stimulate nerve fibres, in
particular, afferent nerves to deliver sensory feedback.
The electrodes will be connected to an electronic processing unit and a
telemetry system that connects them to the sensorised prosthesis,”
explained Dr Beccai. It is expected that it could take five to eight
years before the device has cleared all the tests necessary to prove its
safety, usability and robustness.
For more information about the Cyberhand project and the consortium
involved visit: www.cyberhand.org