Reinforcement Learning Enabled Automatic Impedance Control of a Robotic Knee Prosthesis to Mimic the Intact Knee Motion in a Co-Adapting Environment
This work addresses the challenge of automatic configuration for robotic knee prostheses, which is crucial for their broader adoption by users.
This paper explores the use of reinforcement learning to automatically configure the impedance parameters of a robotic knee prosthesis. The goal is to mimic the intact knee motion in a co-adapting environment, which was successfully achieved through online policy iteration in both simulations and experiments with two able-bodied subjects.
Automatically configuring a robotic prosthesis to fit its user's needs and physical conditions is a great technical challenge and a roadblock to the adoption of the technology. Previously, we have successfully developed reinforcement learning (RL) solutions toward addressing this issue. Yet, our designs were based on using a subjectively prescribed target motion profile for the robotic knee during level ground walking. This is not realistic for different users and for different locomotion tasks. In this study for the first time, we investigated the feasibility of RL enabled automatic configuration of impedance parameter settings for a robotic knee to mimic the intact knee motion in a co-adapting environment. We successfully achieved such tracking control by an online policy iteration. We demonstrated our results in both OpenSim simulations and two able-bodied (AB) subjects.