Assist-As-Needed Control of a Wearable Lightweight Knee Robotic Device

Abstract

Knee joint actuation plays a critical role to keep human walking locomotion and balance under abnormal conditions, such as foot slip or work-related musculoskeletal disorders etc. Wearable assistive robotic knee devices provide additional support and actuation for human walkers. We present assist-as-needed control strategy for a lightweight, highly-backdrivable soft knee assistive device. The control design takes advantages of the custom-built high-performance knee assistive device and the muscle synergy-based human walking actuation model. A model predictive control (MPC) design is used for real-time tuning physical human-robot interactions. Human-in-the-loop simulation results are presented to demonstrate the performance of the robotic control systems under normal walking condition.