• walking strategies
• sensory feedback
• powered orthosis
• emg
• wearable robotics
• hip exoskeleton
• gait assistance

In the last years, we have witnessed one of the greatest revolutions in the scientific world, the development of robotic wearable devices. Among these, exoskeletons are the focus of this thesis. Due to the close contact with the human, they have to comply with several challenging cognitive and physical requirements, such as the implementation of effective assistive strategies able to promote a synergetic cooperation between the robot and the user. In this regard, despite different research groups have demonstrated that the use of lower-limb exoskeletons can reduce biological joint torques and the energetic cost of walking, there is not a clear understanding of which are the ultimate determinants for optimal assistance. The objective of this thesis was twofold: from one side, it aimed at investigating this variability by assessing the efficiency of gait assistive torques provided with different timings with an Active Pelvis Orthosis to six healthy subjects; moreover, the efficacy of introducing augmented sensory feedback describing the provided assistance was evaluated. In fact, we hypothesized that encoding meaningful information about the action of an active orthosis could improve the cooperation with the exoskeleton and reduce the muscular effort. Results indicated that individualized torque timings could effectively reduce the activation of some muscles: in particular, we found muscular reduction on both the RF (i.e. hip flexor) and the GM (i.e. ankle plantar flexor), that might be attributed to different walking strategies used by humans at joint and muscular levels. As for the introduction of sensory feedback, providing augmented feedback helped achieving more repeatable walking patterns, even though it did not improve the reduction in muscular effort obtained with assistance alone.