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Updated: Oct 27, 2025
Oscillation and Reaction Board Techniques for Estimating Inertial Properties of a Below-knee Prosthesis
Published on: May 8, 2014
Validation of Methods for Estimation of Knee Joint Mechanical Impedance During Locomotion Using a Torque-Controllable
Yves F Nazon1, Raveena M Doshi1, Elliott J Rouse1
1Department of Mechanical Engineering, Robotics Institute University of Michigan, Ann Arbor, MI 48109.
Abstract:
The mechanical impedance of the joints of the leg governs the body's response to external disturbances, and its regulation is essential for the completion of tasks of daily life. However, it is still unclear how this quantity is regulated at the knee during dynamic tasks. In this work, we introduce a method to estimate the mechanical impedance of spring-mass systems using a torque-controllable exoskeleton with the intention of extending these methods to characterize the mechanical impedance of the human knee during locomotion. We characterize system bandwidth and intrinsic impedance and present a perturbation-based methodology to identify the mechanical impedance of known spring-mass systems. Our approach was able to obtain accurate estimates of stiffness and inertia, with errors under 3% and ∼13-16%, respectively. This work provides a qualitative and quantitative foundation that will enable accurate estimates of knee joint impedance during locomotion in future works.
