Class: BE209
Group: W1
Members:Laura Bouchelle, Amy Garber, Jay Komarneni, Melissa Simon,
Enzong Yap
Date: December, 2002
Abstract-
In this lab we monitored the change in the angles of knee motion
as walking speed on a treadmill increased (beginning at 1mph increasing
at intervals of 0.5mph ). These angles, as measured by an exercise
apparatus, were calculated two ways: first by averaging the maximum and
minimum voltages over 10 steps using the Virtual Instrument DMM, then by
hand calibrating the reference potentiometers on a window comparator circuit.
Both methods showed that increasing walking speed decreases the maximum
angle and increases the minimum angle made by the knee. As a result,
the increased speed decreased the overall range of motion, and, therefore,
decreased the work done by the knee. Differences in the voltage values
obtained by the DMM and window comparator are accounted for since the DMM
values were averages, whereas the window comparator values were the absolute
maximum and minimum. The results of this experiment do not fully
agree with prior experimentation, but this is probably caused by our observation
of only one joint, whereas full walking gait cycles involve several other
factors such as the angles of the hip and ankle and the frequency of steps.
Overall, the window comparator-exercise apparatus system is highly sensitive
(sensitivity of .5º) and is not greatly affected by noise (frequency
of 341kHz and peak to peak voltage of 14.6mV) and drift (none over 10 minutes),
thus it appears to be an appropriate means for observing gait cycles.