The robotic hand Hannes is developed in Italy at Istituto Italiano di Tecnologia and Centro Protesi INAIL. Hannes is able to replicate the key biological properties of the human hand and is able to restore over 90% of functionality to people with upper-limb amputations.
Image courtesy of IIT-Inail..
A biomimetic prosthetic hand that can replicate the key biological properties of the human hand, including natural synergistic and adaptable movement, biomimetic levels of force and speed, high anthropomorphism, and grasp robustness, is featured on the cover of the latest Science Robotics.
Researchers from Istituto Italiano di Tecnologia (IIT-Italian Institute of Technology) and Italy’s Centro Protesi INAIL (the prosthetic unit of the National Institute for Insurance against Accidents at Work) reported about the development of the prosthesis in an open-access study in the journal.
Developed with researchers, orthopedists, industrial designers, and patients, the Hannes hand can restore over 90 percent of functionality to people with upper-limb amputations.
Hannes is an anthropomorphic, poly-articulated, myoelectric upper-limb prosthetic system including a hand and wrist whose main characteristics are the softness and the ability to dynamically adapt themselves to the shape of objects to grasp. To evaluate the effectiveness and usability of Hannes, pilot trials with people with amputations were performed at Centro Protesi INAIL, and researchers found that after a training period of less than one week patients could autonomously use the device to perform activities of daily living.
The prosthesis can be worn all day and is adjustable to different upper-limb impairments. An array of surface electromyographic sensors, placed within a custom socket, detect the activity of the residual arm muscles, which are actively contracted by the user to perform multiple movements. Moreover, through a specially developed software and a Bluetooth connection, it is possible to customize the operating parameters of the hand, such as the precision and speed of movements, to ensure the most optimized experience for each user.
The Hannes hand has been tested for durability and robustness in a setting that simulated more than one year of usage and almost 500,000 life cycles.
The mechanical design of Hannes is unique, say the researchers, which gives to the prosthesis the versatility and the movement of a natural hand. The underlying mechanism of the hand is a mechanical differential system that allows Hannes to adapt to the object being grasped by using just a single motor. This enhances performance due to its efficiency, and is matched to the 50th percentile human hand size. The prosthesis, which weighs 450 grams, is designed in two sizes, for right and left hands, and for men and women.
The fingers can flex and be positioned in a natural manner, even at rest. In particular, the thumb can be oriented in three different positions to replicate a wide variety of grips, including a fine grip to pick up small objects, a lateral grip, which allows grasping of thin objects, and a power grip capable of grasping and moving heavy loads. The system also permits to pronation and supination of the wrist, allowing grasps in different orientation without relying on harmful patient compensation.
Hannes can perform a full-closed grasp in less than one second, and it can exert a maximum grasp force of 150 N, which the researchers say is well beyond other commercial and research poly-articulated hands, and it has an autonomy of a day of standard use.
The researchers validated the prosthesis’ performance and the human-likeness of its grasping behavior and demonstrated an improved performance compared with existing research or commercial devices. They are identifying investors and industrial partners to prepare the device for commercialization.
The name of the robotic system prosthesis is a tribute to Professor Johannes “Hannes” Schmidl, technical director of the Centro Protesi Inail in the 1960s and a pioneer in upper-limb prosthetics. The Hannes hand was recently awarded the international industrial design prize Compasso d’Oro.
The study, The Hannes hand prosthesis replicates the key biological properties of the human hand, was published in Science Robotics.
Editor’s note: This story was adapted from materials provided by the Istituto Italiano di Tecnologia.
To see a video of the development, visit https://eurekalert.org/multimedia/pub/243551.php.
