Cooperative Ankle-Exoskeleton Control Can Reduce Effort to Recover Balance After Unexpected Disturbances During Walking

摘要

<title>Abstract</title> BackgroundIn the last two decades, lower-limb exoskeletons have been developed to assist human standing and locomotion. One of the ongoing challenges is the cooperation between the exoskeleton balance support and the wearer control. Here we present a cooperative ankle-exoskeleton control strategy to assist in balance recovery after unexpected disturbances during walking, which is inspired on human balance responses.MethodsWe evaluated the novel controller in ten able-bodied participants wearing the ankle modules of the Symbitron exoskeleton. During walking, participants received unexpected forward pushes with different timing and magnitude at the pelvis level, while being supported or not by the robotic assistance provided by the controller.ResultsThe results show that the controller was able to reduce participants’ effort while keeping similar ability to counteract and withstand the balance disturbances (average reduction of 10.09% in soleus activity, 5.20% in gastrocnemius medialis activity and 6.67% in gastrocnemius lateralis activity for the stance leg).ConclusionThe proposed controller was able to cooperate with the able-bodied participants in counteracting perturbations, contributing to the state-of-the-art of bio-inspired cooperative ankle exoskeleton controllers for supporting dynamic balance. In the future, this control strategy may be used in exoskeletons to support and improve balance control in users with motor disabilities.