title: Enabling variable-stiffness hand rehabilitation orthoses with dielectric elastomer transducers.
abstract: Patients affected by motor disorders of the hand and having residual voluntary movements of fingers or wrist can benefit from self-rehabilitation exercises performed with so-called dynamic hand splints. These systems consist of orthoses equipped with elastic cords or springs, which either provide a sustained stretch or resist voluntary movements of fingers or wrist. These simple systems are limited by the impossibility of modulating the mechanical stiffness. This limitation does not allow for customizations and real-time control of the training exercise, which would improve the rehabilitation efficacy. To overcome this limitation, 'active' orthoses equipped with devices that allow for electrical control of the mechanical stiffness are needed. Here, we report on a solution that relies on compact and light-weight electroactive elastic transducers that replace the passive elastic components. We developed a variable-stiffness transducer made of dielectric elastomers, as the most performing types of electromechanically active polymers. The transducer was manufactured with a silicone film and tested with a purposely-developed stiffness control strategy that allowed for electrical modulations of the force-elongation response. Results showed that the proposed new technology is a promising and viable solution to develop electrically controllable dynamic hand orthoses for hand rehabilitation.
authors.affiliation: Queen Mary University of London, School of Engineering & Materials Science, London, UK. Electronic address: f.carpi@qmul.ac.uk.
authors.forename: Federico
authors.initials: F
authors.lastname: Carpi
authors.affiliation: Queen Mary University of London, School of Engineering & Materials Science, London, UK.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Frediani
authors.affiliation: Research Center "E. Piaggio", University of Pisa, Pisa, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Gerboni
authors.affiliation: Research Center "E. Piaggio", University of Pisa, Pisa, Italy.
authors.forename: Jessica
authors.initials: J
authors.lastname: Gemignani
authors.affiliation: Research Center "E. Piaggio", University of Pisa, Pisa, Italy.
authors.forename: Danilo
authors.initials: D
authors.lastname: De Rossi
mesh_terms: D020724:Elastomers; D017097:Electric Impedance; D004566:Electrodes; D004867:Equipment Design; D006225:Hand / Q000502:physiology*; D006801:Humans; D055595:Mechanical Phenomena; D009989:Orthotic Devices; D012046:Rehabilitation / Q000295:instrumentation*; D013165:Splints; D014159:Transducers
chemical_list: D020724:Elastomers
keywords: Actuator; Dielectric elastomer; Electroactive; Electromechanically active; Finger; Polymer; Rehabilitation; Splint; Stiffness; Transducer; Variable; Wrist; hand