Additionally,we measured the motion of
pelvis when an identical user walks 14 meters in 22 steps,20 steps and 17 steps.The
each time-series data of pitch angle are illustrated in Figure 4.
Figure 4:The time-series data of pitch angle
whose forms change as number of steps
Figure 5:The relationship between width of
changing pitch angle and length of a step
The relationship between width of changing pitch angle and length of a step which is
computed by Figure 4 is illustrated in Figure 5.
The experimental data illustrated in Figure 5 shows that length of a step is
computed by the time-series data of pitch angle.
Therefor important parameter of walking
which includes number of steps,length of a
step,and direction of walking,can be computed by using information about the
motion of pelvis which is measured by the gyrometer.And then,the positional
information can also be computed by the parameter
about walking.
4 Experiment
To prove applicability of this system,we
examined how accurately this system can
compute the positioning trajectory.The
experiment was made using the rectangular course whose longer side is 30 meters
and shorter side is 15 meters.The positioning trajectory which computed by this system when user walked along the rectangular
course is illustrated in Figure 6.
Figure 6:
The positioning trajectory computed by this system when user walked
along the rectangular course whose longer
side is 30 meters and shorter side is 15 meters
The experimental data illustrated in Figure 6 shows that the positioning trajectory
be computed very accurately in such a
simple course.
5 Conclusions
Through several basicexperiments,it can
be concluded that this positioning system
has possibility of providing positional information with high accuracy in the case of
walking.
The problem for this positioning system
is that movement in the height direction
and movement by ” non-walking ” methods
like by car and train cannot be computed.
For the purpose of this positioning system
shows,it is very important to compute the
movement using stairs,escalators,elevators,
cars,trains and so on.Theoretically,it is
expected that movement vector can be computed by integrating acceleration measured
by the accelerometer,but it is con . rmed
that this integrating isn ’ t practical,because
accuracy of the accelerometer is very low for
this purpose.
At first,development of an algorithm
which can distinguish modes of action,like
walking,running,going up or down stairs,
standing,sitting,and so on,is necessary for
this problem.And it is important to automatically identify the modes of movement
(e.g.walking)which the personal positioning system can be applied to.On the other
hand,it will be very di . cult to compute directly the positional information when user
is going by elevators,buses,cars,trains and
subways.Therefore,in this case,it is necessary to distinguish transportation mode
(e.g.car,train)which a user is using,and to
use additional information to determine the
location.It is also very interesting that the
other sensors like a microphone for speech
recognition or a barometer for elevation estimation have possibility to give us more
information about user ’ s action.
After discussing about these ideas and doing many experiments to prove the
availability of this positioning system,we will complete this developement of the personal hycan
brid positioning system.And then,we have
to prove how accurately this positioning system can complement GPS.
References
- Hideo KAWAI,Haruyoshi IWAMOTO
and Koji TORII,1988.A Route Navigational Composite System of Pedometer and Azimuth Compass for Human.
T.IEICE,J71-A-11,pp.2054-2062.
- Takayuki TAKAHASHI,Hirofumi OSAWA,Akihiro SUZUKI and Hikaru INOOKA,1995.An Improved Algorithm
and Implementation for the Ambulatory Measuring System of Human Gait.
T.SICE,32-7,pp.1057-1064.
- Koichi SAGAWA,Atsushi INA,
Takayuki TAKAHASHI,Tadashi
ISHIHARA and Hikaru INOOKA,1998.
Estimation of Human Moving Behavior
by Using Acceleration and Air Pressure.
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