Design and Evaluation of a Powered Hip Exoskeleton for Frontal and Sagittal Plane Assistance

Powered exoskeletons have the potential to improve ambulation for millions of individuals who struggle with mobility. Most powered exoskeletons aim to improve walking economy and increase speed by generating propulsive torque in the sagittal plane. However, individuals with mobility impairments typically have limited mediolateral balance, which requires assistance in the frontal plane. Here we present the design and preliminary evaluation of an autonomous powered hip exoskeleton that can generate torque in both the frontal and sagittal planes. The exoskeleton leverages a unique parallel actuator to produce up to 30 Nm of torque while achieving a compact and lightweight design that adds only 3 cm posterior and 8 cm lateral to the user and weighs only 5.3 kg. Preliminary validation tests with two healthy subjects show that the proposed powered hip exoskeleton can successfully assist gait by controlling the frontal plane torque to alter step width and providing sagittal plane torque to assist with hip flexion. A device with these characteristics has the potential to improve both gait economy and balance in clinical populations.