A sEMG-Based Active-Passive Fusion Rehabilitation Method for Ankle Fracture Rehabilitation Robot after Surgery

Abstract

In this letter, an active-passive fusion rehabilitation training method for the ankle fracture rehabilitation robot after surgery is developed. A subject-independent continuous estimation model of ankle torque is proposed based on surface electromyography (sEMG), an online adaptive algorithm for passive rehabilitation training trajectory is designed according to the virtual torque, and healthy subject experiments are carried out. The results of offline training, cross-validation and online estimation show that the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAE</i>, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMSE</i>, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SSE</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i><sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> indices of the proposed model are better than existing methods, verifying the accuracy, generalization ability, and portability of the proposed ankle torque estimation method. The results of adaptive rehabilitation training show that, compared to the force control method with the same level of muscle activation, the interaction torque is reduced by an average of 58% to 72%, and the time delay is within 61 ms, proving the feasibility and efficiency of this method in the ankle fracture rehabilitation robot system.