In the experimental setup, a human subject tracks visual images of force
traces displayed on the monitor by applying appropriate normal forces through
a fingerpad that is in contact with a force sensor (Srinivasan and Chen,
1993). In these experiments, the finger moves by only fractions of a mm,
thus approximating isometric muscular contraction conditions. We had completed
one set of experiments on such force tracking last year, and now we have
expanded the range of target forces and their frequency. During tracking
constant and sinusoidal force targets (three subjects with 3 trials per
stimulus), the mean absolute error increased with constant force magnitude,
target sinusoid frequency and amplitude. The errors for a sinusoid of a
given amplitude are 5 to 40 times higher than those for constant force targets
with the same magnitude. Even at relatively low frequency of 2 Hz, the errors
can be higher than 50% of the sinusoid amplitude at all amplitudes.
|
Click on the following links to read more in specific areas.
|
|
