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Dear Biomch-L readers,
Our group is using a mechanical device to elicit ‘sudden’ perturbations
at the knee joint during walking. The initial step is to stretch the
quadriceps muscle group during various phases of the gait cycle using a
ramp and hold input.
A goniometer is used to quantify both the velocity and amplitude of the
stretch. It is our aim to maintain these two parameters constant. The
question is how to define this constancy, that is, how to define a
constant input to the dynamic system we are dealing with.
Should we
A. Observe the velocity of the moving limb as recorded by the goniometer
and adjust our input
accordingly to obtain a final value for velocity which is always
fixed at say 350 degrees/s (8degree
amplitude). In other words use a relative input, or
B. Input a velocity of say 350 degrees/s (8 degree amplitude)
irrespective of the velocity of the moving
limb, i.e. an absolute input?
Thanks in advance for your help.
Natalie
--
Natalie Mrachacz-Kersting, M.Ed.
Center for Sensory-Motor Interaction
Dept. of Medical Informatics and Image Analysis
Institute of Electronic Systems, Aalborg University
Fredrik Bajersvej 7 D3
DK-9220 Aalborg Ø, Denmark
email: nm@smi.auc.dk
ph: +45 9635 8823
fax: +45 9815 4008
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Our group is using a mechanical device to elicit ‘sudden’ perturbations
at the knee joint during walking. The initial step is to stretch the
quadriceps muscle group during various phases of the gait cycle using a
ramp and hold input.
A goniometer is used to quantify both the velocity and amplitude of the
stretch. It is our aim to maintain these two parameters constant. The
question is how to define this constancy, that is, how to define a
constant input to the dynamic system we are dealing with.
Should we
A. Observe the velocity of the moving limb as recorded by the goniometer
and adjust our input
accordingly to obtain a final value for velocity which is always
fixed at say 350 degrees/s (8degree
amplitude). In other words use a relative input, or
B. Input a velocity of say 350 degrees/s (8 degree amplitude)
irrespective of the velocity of the moving
limb, i.e. an absolute input?
Thanks in advance for your help.
Natalie
--
Natalie Mrachacz-Kersting, M.Ed.
Center for Sensory-Motor Interaction
Dept. of Medical Informatics and Image Analysis
Institute of Electronic Systems, Aalborg University
Fredrik Bajersvej 7 D3
DK-9220 Aalborg Ø, Denmark
email: nm@smi.auc.dk
ph: +45 9635 8823
fax: +45 9815 4008
---------------------------------------------------------------
To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl
For information and archives: http://isb.ri.ccf.org/biomch-l
---------------------------------------------------------------