An Improved mechanical model for the ankle admittance

An Improved mechanical model for the ankle admittance

Farotto, D.

Van der Helm, F.C.T. (mentor)
De Vlugt, E. (mentor)

Mechanical, Maritime and Materials Engineering

Biomechanical Engineering

BME

2014-02-19

Quantification of neuromechanical parameters describing joint admittance is used to improve understanding about human motor control, which is relevant for diagnostics and treatment monitoring of patients suffering from movement disorders. Previous studies used a simple mass-spring-damper (MBK) mechanical model to describe the ankle admittance estimated from small mechanical displacements around a constant mean joint angle i.e. working point. Van Eesbeek used the MBK to describe the admittance for several working points over a wide range of motion (RoM) of the passive ankle using a piece-wise linear approach (LPV). However, the MBK model appeared not sufficient to describe the behavior of the ankle in all working points. This discrepancy was the reason for this study, whose goal is to derive a better model structure for the passive ankle over a large RoM. Results show that a mechanical model made up of 2 springs, 1 damper and 1 mass can approximate the ankle admittance more accurately than a MBK model in each working point. The second spring was meant to approximate the mechanical properties of the Achilles tendon. The result endorses the importance of the tendon mechanical properties when estimating the passive ankle admittance. In addition, it may question the validity of older studies that used MBK mechanical models to estimate joint mechanical properties.

ankle admittance
system identification

http://resolver.tudelft.nl/uuid:b1736955-9727-48fa-96b6-76102c238c0f

2014-04-13

Student theses

master thesis

(c) 2014 Farotto, D.