While Festo’s ExoHand was primarily developed to assist older employees handle repetitive assembly tasks in industry that can only be performed by humans, it is also a pioneer innovation in the area of service robotics, such as rehabilitation. In stroke therapy, for example, this hand orthosis can be used to help treat the first signs of paralysis in patients.
Because all joints and their actuators exist in the form of an exoskeleton outside of the actual hand, the ExoHand can be worn over a human hand or an artificial hand made from silicone. There are eight pneumatic actuators that move the mechanical fingers. The fingers can be actively moved and their strength amplified. The hand movements can be registered and transmitted to robotic hands in real time. The exoskeleton structure supports the human hand externally and simulates the physiological degrees of freedom of the hand.
Eight pneumatic actuators move the exoskeleton. Sensors record the forces, angles and distances. Servo pneumatic open- and closed loop control algorithms allow precise movement of the individual finger joints. The ExoHand thus supports the various possibilities for gripping and touching, which a human hand has. The pneumatic components allow highly flexible and ergonomic control of the individual finger joints. High forces can thus be transmitted precisely in a small space and with a low weight without the system becoming rigid and restrictive.
The ExoHand can be used together with a brain-computer interface to create a closed feedback loop. It can help stroke patients who are showing the first signs of paralysis to restore the missing connection between brain and hand. An electroencephalography signal (EEG) from the brain indicates the patient’s desire to open or close the hand. The active hand orthosis then performs the movement. The result is a training effect, which over time helps patients to move their hand again without any technical assistance. Festo is working together with the Centre for Integrative Neuroscience at the University Hospital Tübingen on this subject.