Measurement of Human Ankle Stiffness Using the Anklebot

In this paper we present initial results using a novel ankle robot to estimate human ankle stiffness. This lower-extremity robotic therapy module was developed at MIT to aid recovery of ankle function. Given the importance of the ankle during locomotion, an accurate estimate of ankle stiffness would be a valuable asset for locomotor rehabilitation, potentially providing a measure of recovery and a quantitative basis to design treatment protocols. We show that the ankle robot provides accurate measurement of ankle configuration and present a simple protocol to estimate ankle stiffness. Our initial ankle stiffness estimates compare favorably with previously published work, indicating that this method may serve as an efficient clinical measurement tool.