title: Experimental Validation of Motor Primitive-Based Control for Leg Exoskeletons during Continuous Multi-Locomotion Tasks.
abstract: An emerging approach to design locomotion assistive devices deals with reproducing desirable biological principles of human locomotion. In this paper, we present a bio-inspired controller for locomotion assistive devices based on the concept of motor primitives. The weighted combination of artificial primitives results in a set of virtual muscle stimulations. These stimulations then activate a virtual musculoskeletal model producing reference assistive torque profiles for different locomotion tasks (i.e., walking, ascending stairs, and descending stairs). The paper reports the validation of the controller through a set of experiments conducted with healthy participants. The proposed controller was tested for the first time with a unilateral leg exoskeleton assisting hip, knee, and ankle joints by delivering a fraction of the computed reference torques. Importantly, subjects performed a track involving ground-level walking, ascending stairs, and descending stairs and several transitions between these tasks. These experiments highlighted the capability of the controller to provide relevant assistive torques and to effectively handle transitions between the tasks. Subjects displayed a natural interaction with the device. Moreover, they significantly decreased the time needed to complete the track when the assistance was provided, as compared to wearing the device with no assistance.
authors.affiliation: Center for Research in Mechatronics, Institute of Mechanics, Materials, and Civil Engineering, Université catholique de Louvain, Louvain-la-Neuve, Belgium; Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium; "Louvain Bionics", Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Virginia
authors.initials: V
authors.lastname: Ruiz Garate
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna , Pontedera, Pisa , Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Parri
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna , Pontedera, Pisa , Italy.
authors.forename: Tingfang
authors.initials: T
authors.lastname: Yan
authors.affiliation: Laboratory of Robotics at the Faculty of Electrical Engineering, University of Ljubljana , Ljubljana , Slovenia.
authors.forename: Marko
authors.initials: M
authors.lastname: Munih
authors.affiliation: Don Carlo Gnocchi Foundation , Florence , Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Molino Lova
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Pontedera, Pisa, Italy; Don Carlo Gnocchi Foundation, Florence, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Vitiello
authors.affiliation: Center for Research in Mechatronics, Institute of Mechanics, Materials, and Civil Engineering, Université catholique de Louvain, Louvain-la-Neuve, Belgium; Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium; "Louvain Bionics", Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Renaud
authors.initials: R
authors.lastname: Ronsse
keywords: bio-inspired; control; exoskeleton; orthosis; primitives