Knee Exoskeleton-Enabled Balance Control of Human Walking Gait With Unexpected Foot Slip

Abstract

Foot slip is one of the leading causes of fall-related injuries during human walking. The underlying slip dynamics help understand bipedal recoverability under gait perturbation and therefore provide a tool to design proactive slip-induced fall prevention strategies. We present a new integrated wearable sensing and exoskeleton-enabled fall prevention under unexpected foot slip. The real-time slip detection is realized with a set of small, wearable inertial measurements units on both legs. We use the balance recoverability and inter-limb coordination analyses to design the balance recovery strategies. The bilateral knee exoskeleton provides assistive torque control and helps walker to follow the designed gait recovery strategies. Multiple subject experiments are presented to demonstrate the exoskeleton-enabled recovery under foot slip. Various critical metrics, including slip distance, velocity, swing leg touch-down time, are systematically compared to assess the efficacy of both the exoskeleton and the controller. The results confirm that incorporating knee exoskeletons as a balance recovery method for human walking is a reliable and robust approach to mitigate or prevent slip-induced falls.