Exoskeleton | EPFL Graph Search

An exoskeleton (from Greek έξω éxō "outer" and σκελετός skeletós "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. Some large exoskeletons are known as "shells". Examples of exoskeletons within animals include the arthropod exoskeleton shared by chelicerates, myriapods, crustaceans, and insects, as well as the shell of certain sponges and the mollusc shell shared by snails, clams, tusk shells, chitons, and nautilus. Some animals, such as the turtle, have both an endoskeleton and an exoskeleton. Role Exoskeletons contain rigid and resistant components that fulfill a set of functional roles in many animals including protection, excretion, sensing, support, feeding, and acting as a barrier against desiccation in terrestrial organisms. Exoskeletons have roles in defense from pests and predator and in providing an attachment framework for musculature. Arthropod exoskelet

Lean synthesis and application to lower-limb exoskeletons

Tristan Hubert Vouga

Mobility impairments are the most prevalent of all disabilities, affecting the life of nearly one in 20 individuals in developed countries. In the most severe cases, they can have dramatic consequences for the social, mental and physical well-being of those impacted. Wearable robots, also known as exoskeletons, are devices that can physically help humans achieve certain tasks by compensating a disability or augmenting their capacity. Such devices have already proven to temporarily restore some physical function such as the ability to walk for individuals who had suffered a spinal cord injury (SCI). As of today, their limited performance has however prevented them from being widely accepted and used in community. Their high cost, bulkiness, weight, poor usability and limited intelligence are often regarded as a cause. Exoskeleton research and development faces several challenges which have so far limited adoption, whether in the medical field or not. These challenges include the unpredictable and complex nature of human users; the important diversity of their pathologies and needs; the long cycles inherent to hardware development and patient testing; together with the difficulty to compare devices' design and mode of action. In an attempt to cope with these challenges, this thesis introduces the lean synthesis framework. It draws on modularity and digital manufacturing to accelerate and reduce the costs of exoskeleton development process. A collection of modules is presented, along with "DualSKin fabrication", a digital fabrication method particularly adapted to the case of wearable robotics, both used by the framework. We tested the framework by developing four lower-limb exoskeletons with different use cases. TWIICE, enabling individuals with a motor-complete SCI to walk again; SPRIINT, for running assistance of individuals with transfemoral amputation; INSPIIRE, for the study of gait and postural control; WIITE, enabling individuals with SCI to perform ski-touring. TWIICE was found to be the lightest exoskeleton capable of climbing stairs and among the fastest of its category. SPRIINT was the first exoskeleton able to assist running in individuals with transfemoral amputation and the fastest exoskeleton for running ever reported. WIITE was the first reported exoskeleton allowing SCI patients to practice ski-touring. INSPIIRE provided important and translatable insights on human gait and postural control. These findings enabled the implementation of a self-balancing controller on TWIICE. The important variety of these use cases exemplifies the diversity addressable by lean synthesis. New device development and fabrication cycles as short as five weeks were possible thanks to a high degree of reusability. Development and manufacturing costs could also be reduced by leveraging on standard components sharing and recycling. The presented DualSkin fabrication method was found to reduce the production costs of prototype structural parts by 93% with respect to CNC machining while remaining competitive for small series up to 500 parts with respect to low-volume injection molding. These findings suggest that the proposed implementation of lean synthesis contributed positively to addressing all of the considered challenges without deteriorating performance. Together, these contributions advocate for lean synthesis as a new tool for both wearable robotics research and product development.

EPFL2019

Hand exoskeleton device

Luca Randazzo

The invention relates to a hand exoskeleton device having a modular nature. The device is designed to be wearable, portable and light in weight, and comprises from one to ten modules each having an actuating mechanism such as a linear actuator coupled with an artificial tendon having a flexible cable or shaft encased into a sheath and an elastic, stretchable portion on its distal end. The exoskeleton allows controlling flexion-extension of the fingers, while keeping natural somatosensorial interactions with the environment surrounding the users. The device is useful to e.g. assist and restore hand functions of users with motor disabilities both during activities of daily living and in neurorehabilitative scenarios, as well in other scenarios such as virtual reality.

2019

Neuroprosthetics to support impaired hand functions: A multidisciplinary approach combining brain-machine interfaces and wearable exoskeletons

Luca Randazzo

Neuroprosthetics, the discipline that aims at interfacing neural systems to artificially engineered devices, has witnessed in recent years important advancements towards the ultimate goal of augmenting and restoring human functions through technology and artificial systems. Research in this field covers a wide range of efforts, from advancing our basic understanding of the neural processes involved into human sensory, motor and cognitive functions, to developing artificial intelligence algorithms for their decoding, to the physical interfacing between artificial devices and the human nervous system and biomechanics. Ultimately, this discipline aims at fusing these systems in order to restore, replace and rehabilitate lost and impaired functions due to motor disabling conditions or traumatic accidents. In this thesis, I present a multidisciplinary approach that aimed at developing a neuroprosthesis for the assistance and restoration of hand functions impaired by neurological disorders or traumatic accidents, such as cerebrovascular accidents and spinal cord injuries. These efforts encompassed the conceptualization and development of a robotic hand exoskeleton and brain-machine interface (BMI) algorithms for its control. Specifically, this thesis focused on the design, development and testing of (i) a novel mechatronic hand exoskeleton to assist hand motions within domestic and clinical settings, (ii) non-invasive BMI approaches based on electroencephalography (EEG) to decode neural correlates of intended hand movements, and on (iii) the closed-loop integration of the proposed exoskeleton and BMI for the sake of providing continuous feedback about ongoing neural modulations through hand motions and to trigger sensorimotor rehabilitation within clinical scenarios. Results showed that the proposed mechatronic system can successfully control hand opening and closing within a fully wearable, portable and lightweight package. The system was tested with users who suffered from motor disabling impairments, showing that it could help them in performing several activities of daily living for the first time since their accidents. From a brain-machine interfacing perspective, this work shows how imagined hand movements can be decoded, through EEG, in parallel with exoskeleton-induced motions, with important implications for the development of more embodied human-machine interaction protocols. Finally, this work shows how the closed-loop control of exoskeleton motions by means of the decoded ongoing neural activity enhances the discriminability of sensorimotor neural patterns and improves the performance of the brain-machine control channel. Overall, the results presented here represent important advancements within the field of neuroprosthetics, with interesting implications for the development of assistive exoskeletal technologies and non-invasive brain-machine interfaces aimed at controlling such systems in clinical or domestic settings, for both assistive and neurorehabilitative purposes.

EPFL2018

Neuroprosthetics to support impaired hand functions: A multidisciplinary approach combining brain-machine interfaces and wearable exoskeletons

Luca Randazzo

EPFL2018

Lean synthesis and application to lower-limb exoskeletons

Tristan Hubert Vouga

EPFL2019