  This work presents a description of the EXOSMOOTH project, oriented to the
benchmarking of lower limb exoskeletons performance. In the field of assisted
walking by powered lower limb exoskeletons, the EXOSMOOTH project proposes an
experiment that targets two scientific questions. The first question is related
to the effectiveness of a novel control strategy for smooth assistance. Current
assist strategies are based on controllers that switch the assistance level
based on the gait segmentation provided by a finite state machine. The proposed
strategy aims at managing phase transitions to provide a smoother assistance to
the user, thus increasing the device transparency and comfort for the user. The
second question is the role of the actuation at the ankle joint in assisted
walking. Many novel exoskeletons devised for industrial applications do not
feature an actuated ankle joint. In the EXOSMOOTH project, the ankle joint
actuation will be one experimental factor to have a direct assessment of the
role of an actuated joint in assisted walking. Preliminary results of 15
healthy subjects walking at different speeds while wearing a lower limb
exoskeleton supported the rationale behind this question: having an actuated
ankle joint could potentially reduce the torques applied by the user by a
maximum value of 85 Nm. The two aforementioned questions will be investigated
in a protocol that includes walking on a treadmill and on flat ground, with or
without slope, and with a load applied on the back. In addition, the
interaction forces measured at the exoskeleton harnesses will be used to assess
the comfort of the user and the effectiveness of the control strategy to
improve transparency.
