Fig. 12 shows the average of lap time by each
interface. t test of Fig. 12 shows p = 0.17 > 0.05,
therefore there is no significant difference between
two lap times. Thus, it can be said that proposed in-
terface has equivalent operability to the conventional
interface. In addition, let us focus on the transition
of the control inputs during experiment in both inter-
face shown in Fig. 13. From this figure, it is observed
that the control inputs by the stick controller are os-
cillated while the control inputs by propose interface
smoothly changed. From this oscillation, the stick
controller needs fine correction operation. In particu-
lar, transition of v
ref
is largely oscillated. This means
the velocity of the PM-W is also oscillated. This kinds
of motion cannot provide comfortable ride or easy op-
eration.
Thus, from the viewpointsof lap time and smooth-
ness of the control inputs, it is turned out that the pro-
posed interface provides smooth operation compared
to the conventional interface though there is no dif-
ferences between the lap times by the proposed and
conventional interface.
From the above, it is appropriate that the interface
using strain at the root of handle post is adopted for
”vehicle mode”, because it can be regarded that the
operability of proposed interface is equal to or more
than the conventional interface.
5 CONCLUSION
This paper presented Personal Mobility with assis-
tive Walker (PM-W). PM-W has two mobile modes:
”walking assist mode” and ”vehicle mode”. In ”walk-
ing assist mode”, PM-W assists user’s walking by
driving two wheels while user saddles on the seat and
walks. In ”vehicle mode”, user controls PM-W like
an electric bike or conventional senior cart. There-
for a certain control interface is needed in ”vehicle
mode”. Thus, this paper develops the interface for
”vehicle mode”.
The main contact point between user and PM-W
is the handle. The handle is used as a handrail for
elderlies safe in both modes. Therefore the handle
should not have any moving parts on it such as throttle
lever or stick controller. From this things, the bend-
ing strain at the root of the handle post is focused on
for the interface. When user applies own forces to the
handle, the handle post has a strain. In order to realize
the interface using bending strain at the handle post,
FEM was conducted to find the suitable strain part for
the interface. As a result, the vertical and horizontal
strain at the root of the handle post is used for the in-
puts of the interface. In order to verify the operability
of this interface, the basic experiment was conducted.
From the results of the experiment, it is appropriate
that the interface using strain at the root of handle
post is adopted for ”vehicle mode”, because it can be
regarded that the operability of proposed interface is
equal to or more than the conventional interface.
As the future works, we will develop the control
scheme for walking assists mode including the stabil-
ity of the user.
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