Experimental validation of motor primitive-based control for leg exoskeletons during continuous multi-locomotion tasks

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

Motor primitive-based control for lower-limb exoskeletons

Assistive technology forecasts better autonomy for people with lifelong disabilities and for the elderly facing motor decline. As the population of developed countries is becoming greyer, there is thus a high probability of observing a significant increase in the demand for assistive locomotion devices. Designing the controller for such devices is not trivial, and requires both to set up a compliant framework and to manage the cross adaptation between the device and its user (the so-called interface). Taking inspiration from neuromechanical principles governing human locomotion is an approach which is currently investigated by several groups to address these challenges

Motor primitive-based control for lower-limb exoskeletons

Assistive technology forecasts better autonomy for people with lifelong disabilities and for the elderly facing motor decline. As the population of developed countries is becoming greyer, there is thus a high probability of observing a significant increase in the demand for assistive locomotion devices. Designing the controller for such devices is not trivial, and requires both to set up a compliant framework and to manage the cross adaptation between the device and its user (the so-called interface). Taking inspiration from neuromechanical principles governing human locomotion is an approach which is currently investigated by several groups to address these challenges