Technical Field
[0001] The present invention relates to an assisting robot.
Background Art
[0002] PTL 1 discloses an assisting robot that helps a care receiver to stand up. The assisting
robot has two drive axes: A shaft, as one of the drive axes, moves linearly in a vertical
direction. The other drive axis is a table provided to the upper end of the shaft
in a pivotable manner. With the care receiver in a sitting posture having his/her
elbows on the table, the assisting robot pivots (forward-rotates) the table and moves
the table into an ascension-ready position and thereafter raises the table to make
the care receiver stand up.
[0003] PTL 2 discloses the preamble of claim 1.
PRIOR ART REFERENCES
BRIEF SUMMARY OF THE INVENTION
Technical Problem
[0005] The assisting robot first rotates the table forward while the elbows of the care
receiver in the sitting posture are placed on the table. Since the table is raised
by rotating forward, the upper body of the care receiver is lifted as the table starts
rotating forward.
[0006] Here, while in the sitting posture in which the care receiver is seated on a seat
surface, the center of gravity of the care receiver is normally separated away from
the ground position in contact with feet of the care receiver. When the upper body
of the care receiver is lifted by the forward rotation of the table from this state,
a force is generated that causes the upper body of the care receiver to separate rearward
from the table of the assisting robot. For this reason, the care receiver exerts force
to keep from separating away from the table and feels discomfort as a result.
[0007] It is an object of the present invention to provide an assisting robot that can suppress
discomfort to a care receiver during a standing-assistance operation.
Solution to Problem
[0008] An assisting robot according to the present invention is defined in claim 1.
[0009] According to the present invention, the first operation is an operation in which
lowering the elevator and forward-rotating the arm are performed in a coordinated
manner. The upper body of the care receiver is tilted forward by forward-rotating
the arm. Here, in the first operation, the holder is raised with respect to the elevator
by forward-rotating the arm, but the elevator is lowered with respect to the base
by lowering the elevator. As a result, in the first operation, at least a portion
of the raising of the holder with respect to the elevator by forward-rotating the
arm is offset by lowering the elevator.
[0010] In this way, when the center of gravity G of the care receiver moves forward from
its position during the initial sitting posture, in the case of the first operation
described above, the amount the upper body of the care receiver is raised is reduced
compared to the amount with just forward-rotating the arm as performed conventionally.
Therefore, in the initial stage from the sitting posture to the standing posture,
the amount the upper body of the care receiver is lifted is reduced, thereby reducing
discomfort to the care receiver.
Brief Description of Drawings
[0011]
[FIG. 1] FIG. 1 is a rear perspective view showing the external appearance of an assisting
robot according to the present embodiment.
[FIG. 2] FIG. 2 is a view from the right side showing the structure of the assisting
robot in which a care receiver is in an initial sitting posture.
[FIG. 3] FIG. 3 is a view from the right side showing the structure of the assisting
robot in which a care receiver is in an initial sitting posture.
[FIG. 4] FIG. 4 is a view from the right side showing the structure of the assisting
robot in which a care receiver is in an initial sitting posture.
[FIG. 5A] FIG. 5A shows a trace of the shoulder position P of the care receiver and
the angle θ of the trunk receiver at the shoulder positions P1, P2, P3 during a standing
operation of the care receiver that uses an assisting robot.
[FIG. 5B] FIG. 5B shows a change in time of the angle of the trunk receiver from the
beginning to end of assistance in the standing operation of the care receiver.
[FIG. 6A] FIG. 6A shows, for comparison, a trace of the shoulder position Pa and an
angle θa of the trunk at the shoulder positions Pa1, Pa2, Pa3 during a standing operation
of a healthy subject.
[FIG. 6B] FIG. 6B shows an angle θa of the trunk from the beginning to end of operation
in the standing operation of the healthy subject.
DESCRIPTION OF EMBODIMENTS
(1. Configuration of an assisting robot 1)
[0012] An assisting robot 1 assists a care receiver M (shown in FIG. 2) in standing up from
a sitting posture to a standing posture, and assists the care receiver M in sitting
down from a standing posture to the sitting posture. In particular, the assisting
robot 1 according to the present embodiment is primarily targeted to a care receiver
M who has difficulty standing up by oneself, and is effectively used, for example,
in assisting the pulling down and pulling up of bottoms (i.e., clothes worn on the
lower body) of the care receiver M and assisting the care receiver M in performing
a bowel movement. With an assisting robot 1 supporting the upper body of the care
receiver M in a standing posture, a single caregiver can perform the above-mentioned
treatment of the care receiver M. In other words, the standing posture in the present
embodiment refers to a state in which at least the lower body of the care receiver
M is upright, and does not refer to a state in which both the upper body and the lower
body are upright.
[0013] Although the assisting robot 1 of the present embodiment is described for the purpose
of assisting in raising only the lower body of the care receiver M to a standing posture,
it is also possible for the assisting robot 1 to assist in raising both the lower
body and upper body of a care receiver M to the standing posture.
[0014] As shown in FIGS. 1 and 2, the assisting robot 1 has a base 10, wheels 20, an elevator
30, an arm 40, a holder 50, a grip 60, a lower leg contact section 70, and a control
device 80. In the following, front, rear, left, right, up, and down, as shown in FIG.
1, are front, rear, left, right, up, and down as seen from the care receiver M. The
base 10 includes a frame 11, a support column 12, a footrest 13, and a fixed cover
14. The frame 11 is located slightly apart from and is roughly horizontal with a ground
surface 2 (floor, ground).
[0015] The support column 12 is fixed to the frame 11 and erected upward from the front
of the upper surface of the frame 11. The support column 12 is disposed at the center
in the left-right direction at the front of the frame 11. In the present embodiment,
the assisting robot 1 has one support column 12, but two or more support columns 12
may be provided.
[0016] The footrest 13 is fixed to the rear of the top surface of the frame 11. A contact
mark 13a for the feet of the care receiver M is marked on the top surface of the footrest
13. That is, the contact mark 13a guides the position of the feet of the care receiver
M. As shown in FIG. 1, the fixed cover 14 is fixed to the frame 11 or the support
column 12, and encloses the periphery of the lower portion of an elevator main body
31 of the elevator 30 described later.
[0017] As shown in FIG. 1, the wheels 20 are arranged at the four corners (front, rear,
left and right) of the frame 11. The wheels 20 have a locking function for restricting
rotation. In the present embodiment, the wheels 20 freely rotate, but the wheels 20
may be provided such that they are driven by a driving device.
[0018] The elevator 30 includes the elevator main body 31, a pivot support 32, and an elevator
cover 33. As shown in FIG. 2, the elevator main body 31 has an elongated shape in
the vertical direction and is provided to the front face of the support column 12
so as to be linearly movable in the vertical direction. The elevator main body 31
is guided by a guide (not shown) on the front face of the support column 12 and is
driven by a linear motion device (not shown) . The elevator main body 31 is enclosed
by the fixed cover 14.
[0019] The pivot support 32 is provided on the upper end of the elevator main body 31 and
has a pivot axis 32a that is parallel to the left-right direction. Specifically, the
pivot support 32 protrudes rearward from the upper end of the elevator main body 31.
That is, the pivot axis 32a is positioned rearward of the support column 12 and the
elevator main body 31.
[0020] As shown in FIG. 1, the elevator cover 33 is fixed to the elevator 30 and encloses
the elevator 30. Further, the elevator cover 33 encloses the support column 12 and
the fixed cover 14. The elevator cover 33 also overlaps the fixed cover 14 even when
the elevator 30 is in a raised position. In the present embodiment, the assisting
robot 1 has one elevator 30 because it has one support column 12, but if the assisting
robot 1 has two or more support columns 12, the assisting robot 1 will be provided
with a number of elevators 30 corresponding to the number of support columns 12.
[0021] The arm 40 is provided so as to be capable of pivoting about the pivot axis 32a of
the pivot support 32 of the elevator 30 as a central axis. The arm 40 is pivoted by
an arm driving device (not shown). The arm 40 pivots to a position higher than the
pivot support 32. That is, the pivot range of the arm 40 spans from the state where
the tip of the arm 40 extends to the rear of the pivot support 32 (shown in FIG. 2),
to the state where the tip of the arm 40 is in the vicinity above the pivot support
32 or the elevator main body 31 (shown in FIG. 4). When the assisting robot 1 assists
in standing, the arm 40 rotates forward from the rear-extended state, and when the
assisting robot 1 assists in sitting down, the arm 40 rotates rearward to the rear-extended
state.
[0022] The holder 50 is provided at the distal end of the arm 40 and holds the upper body
of the care receiver M. In the present embodiment, the holder 50 includes a trunk
receiving section 51 that comes into contact with the trunk of the care receiver M
and an underarm receiving part 52 that supports both underarms of the care receiver
M. Furthermore, the holder 50 may be provided with only one of the trunk receiving
section 51 or the underarm receiving part 52.
[0023] The trunk receiving section 51 supports the trunk of the care receiver M from below.
The trunk receiving section 51 has a planar shape and is made of a cushion material.
The trunk receiving section 51 has an initial shape corresponding to the body of the
standard care receiver M and is flexibly deformed to accommodate the body of each
care receiver M. In the present embodiment, the trunk receiving section 51 comes into
contact with the chest and abdomen of the care receiver M.
[0024] The underarm receiving part 52 has an arc shape and is disposed on the left and right
sides of the trunk receiving section 51 such that an arc opening faces upward. The
underarm receiving part 52 supports the upper body of the care receiver M by supporting
the underarms of the care receiver M from below. Further, by sandwiching both underarms
of the care receiver M from the front and rear direction, the underarm receiving part
52 restricts back and forth movement of the care receiver M. Accordingly, the trunk
receiving section 51 and the underarm receiving part 52 can control the shoulder position
P of the care receiver M in a state held in place by the holder 50.
[0025] By the arm 40 pivoting with respect to the elevator 30, the center line in the left-right
direction of the trunk receiving section 51 is pivoted in the range of 20° to 110°
with respect to the vertical line. Within the range of angles 20° to 90° of the center
line of the trunk receiving section 51, the trunk receiving section 51 is directed
upward and rearward. On the other hand, within the range of angles 90° to 110° of
the trunk receiving section 51, the trunk receiving section 51 is directed upward
and forward.
[0026] The grip 60 has a U-shape, and both ends of the U-shape of the grip 60 are fixed
to the lower surface of the trunk receiving section 51. The central portion of the
grip 60 is located in front of the trunk receiving section 51 and gripped by the care
receiver M held in the holder 50.
[0027] The lower leg contact section 70 determines the position and posture of the lower
body of the care receiver M in the sitting posture by coming into contact with the
front part of the lower leg (shin or knee) of the care receiver M in the sitting posture.
In particular, the position of the feet is determined to some extent. The lower leg
contact section 70 is fixed to the support column 12 of the base 10. The lower leg
contact section 70 includes two support members 71 and a lower leg pad 72.
[0028] The support members 71 have an L-shape. One end of the L-shaped support member 71
is fixed to the support column 12, and the other end of the L-shaped support member
71 is positioned behind the support column 12. The lower leg contact main body 72
is fixed to the other end of the support member 71 and is positioned behind the elevator
cover 33 and below the pivot support 32. The lower leg pad contact main body 72 is
a part that comes in contact with the front part of the lower leg of the care receiver
M, has a planar shape, and is made of the cushion material.
[0029] The control device 80 is fixed to a frame 11 of the base 10 and erected upward from
the front top surface of the frame 11. The control device 80 is positioned next to
the support column 12. The control device 80 controls vertical movement of the elevator
30 and pivoting of the arm 40 to assist the care receiver M in standing up and sitting
down.
[0030] When an operator (the care receiver M or the caregiver) executes an adjustment operation
for a standing start height, the control device 80 controls only the vertical movement
of the elevator 30 and does not pivot the arm 40 at this time. That is, the control
device 80 adjusts the standing start height according to the elongation of the care
receiver M.
[0031] Furthermore, a standing-assistance program to be used during a standing-assistance
operation is stored in the control device 80 beforehand. As a standing-assistance
operation is executed by the operator (the care receiver M or the caregiver), the
control device 80 executes the standing-assistance program and controls the vertical
movement of the elevator 30 and pivoting of the arm 40. Additionally, a sitting-assistance
program to be used during a sitting-assistance operation is stored in the control
device 80 beforehand. As a sitting-assistance operation is executed by the operator
(the care receiver M or the caregiver), the control device 80 executes the sitting-assistance
program and controls the vertical movement of the elevator 30 and pivoting of the
arm 40. Further, the control device 80 corrects the standing-assistance program and
the sitting-assistance program in accordance with the standing start height.
(2. Standing-assistance operation by the assisting robot 1)
[0032] The standing-assistance operation with respect to the care receiver M by the assisting
robot 1 will be described with reference to FIGS. 2 to 4. In FIGS. 2 to 4, the bold
solid line shows the trace of the shoulder position P during a standing operation
of the care receiver M, and the thick broken line shows the trace of the center of
gravity G during the standing operation of the care receiver M. The standing-assistance
operation is an operation that moves the assisting robot 1 from an initial state shown
in FIG. 2, to an intermediate state shown in FIG. 3, and then to a final state shown
in FIG. 4. That is, by way of the standing-assistance operation, the care receiver
M moves from an initial sitting posture shown in FIG. 2, to an intermediate posture
shown in FIG. 3, and then to a standing posture shown in FIG. 4. That is, the control
device 80 conducts the vertical movement of the elevator 30 and forward rotation of
the arm 40 so that the shoulder position P moves along the trace shown in FIGS. 2
to 4.
[0033] As shown in FIG. 2, in the initial state of the standing-assistance operation, the
care receiver M is seated on a seat surface 3 (the sitting posture) . The assisting
robot 1 is set to the initial state of the standing-assistance operation by operation
of the care receiver M or a caregiver. In the standing-assistance program, the initial
state of the assisting robot 1 is a state in which the holder 50 is positioned furthest
to the rear. That is, the initial state of the assisting robot 1 is a state in which
the arm 40 extends rearward. The lower body of the care receiver M is disposed in
a space below the holder 50. The feet of the care receiver M are positioned on the
contact mark 13a. The lower legs of the care receiver M come in contact with the rear
surface of the lower leg pad 72.
[0034] In this state, the control device 80 moves the elevator 30 vertically as a result
of the care receiver M or the caregiver performing a vertical movement operation of
only the elevator 30 according to the height of the upper body of the care receiver
M who is in a sitting posture on the seating surface 3. In this way, the front surface
of the trunk of the care receiver M comes into contact with a trunk holding surface
of the trunk receiving section 51. Further, the care receiver M places the underarms
on the underarm receiving part 52, and the care receiver M grips the grip 60. In this
initial state, the upper body of the care receiver M is in a slightly forward-leaning
posture. However, the position of the center of gravity G1 in the front-rear direction
of the care receiver M in the initial state is located behind the front-rear span
F of the feet of the care receiver M.
[0035] Subsequently, when the care receiver M or the caregiver starts the standing-assistance
operation, the control device 80 lowers the elevator 30 and forward-rotates the arm
40 in a coordinated manner in accordance with the standing-assistance program. Here,
the operation from the initial sitting posture to the intermediate posture of the
care receiver M is referred to as the first operation. That is, the first operation
is an operation in which lowering the elevator 30 and forward-rotating the arm 40
is performed in a coordinated manner for at least a part of a period of time from
the initial sitting posture to the intermediate posture.
[0036] In the present embodiment, the coordinated operation of lowering the elevator 30
and forward-rotating the arm 40 is performed for the entire period from the initial
sitting posture to the intermediate posture. Of course, coordinated operation can
also be executed for only a part of the period. At this time, the arm 40 only forward-rotates
and does not rearward-rotate, and the elevator 30 only descends and does not rise.
[0037] As shown in FIGS. 2 and 3, the first operation moves the shoulder position P of the
care receiver M forward in a roughly horizontal manner. In the first operation, the
holder 50 rises with respect to the elevator 30 by forward rotation of the arm 40.
However, as the elevator 30 descends, the shoulder position P moves in a roughly horizontal
manner. Here, "roughly horizontal" includes states that are slightly inclined upward
or downward with respect to the horizontal.
[0038] Furthermore, in the first operation, by forward rotation of the arm 40, the trunk
holding surface of the trunk receiving section 51 tilts forward and moves forward.
Therefore, due to the coordinated first operation, the shoulder position P of the
care receiver M moves forward and the rear end of the trunk receiving section 51 rises.
Accordingly, the upper body of the care receiver M tilts forward and the vicinity
of the abdomen of the care receiver M is lifted. As a result of such a first operation,
while the buttocks of the care receiver M are kept in contact with the seat surface
3, the back muscles of the care receiver M extend and the pelvis stands upright. In
this way, the holder 50 supports the care receiver M having such a posture in a stable
manner.
[0039] Additionally, as shown in FIG. 3, in the intermediate posture, the position in the
front-rear direction of the center of gravity G2 of the care receiver M enters the
front-rear span F of the ground surface in contact with the feet of the care receiver
M. Accordingly, although the care receiver M can not stand up on his/her own, in the
intermediate posture, the care receiver M is in a posture that makes it easy for him/her
to support him/herself in a stable manner with his/her own feet.
[0040] Whether or not the position of the center of gravity G2 of the care receiver M in
the front-rear direction is within the front-rear span F of the ground surface in
contact with the feet can be predicted by the extension and the weight of the care
receiver M. Therefore, by predicting the center of gravity G of the care receiver
M in advance and setting vertical movement of the elevator 30 and the angle of forward
rotation of the arm 40, the above can be realized.
[0041] Additionally, it is also possible to make the above judgment by measuring the mass
on the holder 50 and determining whether or not the mass reaches a predetermined percentage
of the mass of the upper body of the care receiver M. Further, the above judgment
can be made based on whether or not the rear load received by the holder 50 from the
care receiver M has reached a value that is equal to or less than a predetermined
value. Furthermore, the above judgment can also be made depending on whether or not
the inclination of the upper body of the care receiver M has reached a predetermined
value or more.
[0042] Accordingly, the control device 80 switches the operation of the elevator 30 from
lowering to raising. In the present embodiment, the control device 80 coordinates
upward movement of the elevator 30 and forward rotation of the arm 40 in accordance
with the standing-assistance program. Here, the operation from the intermediate posture
of the care receiver M to the standing posture is referred to as a second operation.
That is, in the second operation, the coordination between raising of the elevator
30 and forward rotation of the arm 40 is performed for at least a part of a period
from the intermediate posture to the standing posture.
[0043] In the present embodiment, the coordinated operation of raising the elevator 30 and
forward-rotating the arm 40 is performed for the entire period from the intermediate
posture to the standing posture. Of course, coordinated operation can also be executed
for only a part of the period. At this time, the arm 40 is only rotating forward and
does not rotate rearward, and the elevator 30 only rises and does not descend.
[0044] As shown in FIGS. 3 and 4, the shoulder position P of the care receiver M rises upward
in a roughly direct manner while slightly moving forward from the intermediate posture.
That is, the holder 50 moves slightly forward due to forward rotation of the arm 40
and rises mainly due to rising of the elevator 30.
[0045] By performing the second operation, the buttocks of the care receiver M moves upward
and away from the seating surface 3. In the second operation, by the forward rotation
of the arm 40, the trunk holding surface of the trunk receiving portion 51 further
tilts forward. The upper body of the care receiver M is raised and further tilted
forward. Accordingly, by way of the second operation, when the upper body of the care
receiver M rises, a state in which the back muscles of the care receiver M are extended
is maintained. Therefore, during the second operation, the holder 50 can support the
care receiver M in a stable manner.
[0046] Furthermore, during the second movement, the position (G2 to G3) of the center of
gravity G of the care receiver M in the front-rear direction is located within the
front-rear span F of the ground surface in contact with the feet of the care receiver
M. In this way, the care receiver M feels secure when the upper body of the care receiver
M rises.
(3. Position of the pivot axis 32a)
[0047] Next, the position of the pivot axis 32a will be described with reference to FIGS.
2 to 4. The height from the top surface of the footrest 13 to the pivot axis 32a moves
up and down within a range of 400 to 1000 mm through the vertical movement of the
elevator 30. In the standing-assistance program, when the assisting robot 1 is in
the intermediate state shown in FIG. 3, the pivot axis 32a is positioned at the lowest
position, and when the assisting robot 1 is in the final state shown in FIG. 4, the
pivot axis 32a is positioned at the highest position. However, since the vertical
movement of the elevator 30 can be suitably adjusted, the lowest position and the
highest position of the pivot axis 32a can be changed according to the elongation
of the care receiver M.
[0048] The center in the left-right direction of the trunk receiving section 51 comes into
contact with the center in the left-right direction of a front surface of the body
of the care receiver M. The distance L (shown in FIGS. 2 and 4) between a line passing
through the shoulder position P and parallel to the trunk holding surface, which is
provided for the care receiver M by the trunk receiving section 51 of the holder 50,
and the pivot axis 32a of the arm 40 is 230 to 290 mm. In particular, the distance
L is preferably 250 to 270 mm.
[0049] The pivot axis 32a is located in front of the front-rear span F of the ground surface
in contact with the feet of the care receiver M. The pivot axis 32a is located 250
to 450 mm in front of the ground contact position of the heel of the foot of the care
receiver M. In particular, the distance between the pivot axis 32a and said ground
contact position is preferably 300 to 400 mm.
[0050] During the first operation, the pivot axis 32a descends within the height range
of the upper body of the care receiver M, that is, within the range from the lower
surface (the seat surface 3) of the buttocks of the care receiver M to the top of
the head. In particular, in the present embodiment, the pivot axis 32a descends within
the height range of the body (chest and abdomen) of the care receiver M during the
first operation.
[0051] Further, as shown in FIG. 2, the pivot axis 32a is located in front of the head of
the care receiver M in the initial sitting posture. Further, as shown in FIG. 4, the
pivot axis 32a is located behind the head of the care receiver M in the standing posture
while the care receiver M is held in the holder 50.
(4. Shoulder position of the care receiver and a healthy subject)
[0052] Next, the trace of the shoulder position P of the care receiver M and the change
of the angle θ of the trunk receiving section 51 during the standing-assistance operation
will be described with reference to FIGS. 5A and 5B. In FIGS. 5A and 5B, T1, T2, and
T3 represent times, and P1(T1), P2(T2) and P3(T3) represent the shoulder positions
at T1, T2, and T3, respectively.
[0053] For comparison, the trace of the position Pa of a healthy subject and the trace of
inclination angle θa of the trunk when a healthy subject performs the standing operation
will be described with reference to FIGS. 6A and 6B. In FIGS. 6A and 6B, Ta1, Ta2,
Ta3 and Ta4 represent times, and Pa1 (Ta1), Pa2 (Ta2), Pa3 (Ta3), Pa4 (Ta4) represent
the shoulder positions at Ta1, Ta2, Ta3, and Ta4, respectively. Further, the trace
of the shoulder position P of the care receiver M and the change of the angle θ of
the trunk receiving section 51 as well as the trace of the shoulder position Pa of
the healthy subject and the change of the angle θa of the trunk, are different, for
example, depending on the extended length, sitting height, the length of the legs,
and the like.
[0054] As shown in FIG. 5A, the shoulder position P of the care receiver M is positioned
at P1 at the time T1 when the care receiver M is in the initial sitting posture, at
P2 at the time of the intermediate posture T2, and at P3 at the time of the standing
posture T3. The shoulder position P moves forward in a roughly horizontal manner from
P1 to P2. Thereafter, the shoulder position P moves forward from P2 and rises to reach
P3. The shoulder position P rises while moving forward from P1 to P3. P1 is the lowest
position, and P3 is the highest position.
[0055] The angle θ of the trunk receiving section 51 (equivalent to the angle of the trunk
of the care receiver M), as shown in FIGS. 5A and 5B, is 35° at time T1 when the care
receiver M is in the initial sitting posture, 64° at time T2 of the intermediate posture,
and 95° at time T3 of the standing posture. As shown in Figure 5B, the angle θ trends
upward.
[0056] On the other hand, as shown in FIG. 6A, the shoulder position Pa of the healthy subject
is at position Pa1 at time Ta1 when the healthy subject is in the initial sitting
posture and is positioned at the lowest position Pa2 at time Ta2 when the upper body
is tilted forward and the buttocks are lifted away from the seating surface 3. After
that, the shoulder position Pa of the healthy subject rises and is located at Pa4
at time Ta4 of the standing posture.
[0057] The trunk angle θa of the healthy subject at time Ta1 of the initial sitting posture
is 5°, and by gradually tilting forward, at time Ta2, the angle θa reaches 44°, when
the buttocks separates from the seat surface 3. Immediately after that at time Ta3,
the trunk angle θa is maximized, and then the trunk rises as the angle θa becomes
small. The trunk angle θa is 3° at time Ta4 of the standing posture.
[0058] The shoulder position P of the care receiver M approximately follows the trace of
the shoulder position Pa of the healthy subject from the vicinity of Pa2 to somewhere
in between Pa3 and Pa4. Therefore, since the care receiver M stands up after slidong
the upper body forward like the healthy subject, the care receiver M can comfortably
stand up with the center of gravity G on the soles of the feet. However, whereas the
trunk angle θa becomes small after becoming large in the healthy individuals, the
angle θ of the trunk receiving section 51 continues to become large. The reason for
this difference is that the final standing posture is different.
(5. Effect)
[0059] The assisting robot 1 described above includes: the base 10, the elevator 30 for
linear movement in the vertical direction with respect to the base 10, the arm 40
that is attached in a pivotable manner to the elevator 30 with the predetermined pivot
axis 32a, a holder 50 provided at the end of the arm 40 for holding the upper body
of the care receiver M, and the control device 80 that controls vertical movement
of the elevator 30 and pivoting of the arm 40 to assist the care receiver M in standing
up from the sitting posture to the standing posture.
[0060] The control device 80 lowers the elevator 30 and forward-rotates the arm 40 in a
coordinated manner for at least a part of a period from when the care receiver M is
in the initial sitting posture (T1 in FIG. 5A and FIG. 5B), shown in FIG. 2, to the
intermediate posture (T2 of FIG. 5A and FIG. 5B), shown in FIG. 3. Furthermore, the
control device 80 executes the second operation that raises the elevator 30 during
a period from the intermediate posture shown in FIG. 3 (T2 of FIG. 5A and FIG. 5B)
to the standing posture as shown in FIG. 4 (T3 in FIGS. 5A and 5B) .
[0061] The first operation by the control device 80 is an operation in which the lowering
of the elevator 30 and forward rotation of the arm 40 are performed in a coordinated
manner. The upper body of the care receiver M is tilted by the forward rotation of
the arm 40. Here, although the first operation raises the holder 50 with respect to
the elevator 30 by forward rotation of the arm 40, the elevator 30 is lowered with
respect to the base 10. As a result, in the first operation, at least a portion of
the raising operation of the holder 50 with respect to the elevator 30 by the forward
rotation of the arm 40 is offset by the lowering operation of the elevator 30.
[0062] In this way, when the center of gravity G of the care receiver M moves forward from
its position during the initial sitting posture, in the case of the first operation
described above, the amount of the upper body of the care receiver M raised is suppressed
compared to the amount with just the forward rotation of the arm as before. Therefore,
in the initial stage from the sitting posture to the standing posture, the amount
of the upper body of the care receiver M lifted is reduced, thereby suppressing discomfort
to the care receiver M.
[0063] The holder 50 includes the trunk receiving section 51 which comes into contact with
the trunk of the care receiver M. The first operation is an operation that raises
the rear end of the trunk receiving section 51 by coordinating the lowering of the
elevator 30 and the forward rotation of the arm 40. Through such a first operation,
the spine of the care receiver M extends in a state in which the pelvis is upright.
In this way, the holder 50 supports the care receiver M having such a posture in a
stable manner. Further, in the second operation, the assisting robot 1 stabilizes
the care receiver M and moves the care receiver M to a standing posture. In other
words, the care receiver M is provided with a sense of security.
[0064] Additionally, for at least a part of a period, by coordinating the lowering of the
elevator 30 and the forward rotation of the arm 40, the first operation moves the
shoulder position P of the care receiver M held by the holder 50 forward in an approximately
horizontal manner. By doing so, from the time T1 of the initial sitting posture to
the time T2 of the intermediate posture, the care receiver can get ready to stand
up without feeling burdened.
[0065] The first operation and the second operation by the control device 80 include an
operation for forward-rotating the arm 40 and do not include an operation for rearward-rotating
the arm 40 . That is, the angle of the trunk of the care receiver M changes only in
one direction. As shown in FIGS. 6A and 6B, in the case of the healthy subject, the
angle of the trunk changes direction midway. By performing the first operation and
the second operation in the manner described above, the assisting robot 1 is effective
in the case in which the objective is to assist in raising only the lower body of
the care receiver M to the standing posture.
[0066] Additionally, for at least a part of a period from the time T2 of the intermediate
posture to the time T3 of the standing posture, the second operation is an operation
in which the raising of the elevator 30 and the forward rotation of the arm 40 are
performed in a coordinated manner. That is, the care receiver M moves into a head
forward posture in the second operation. Thus, in particular, the assisting robot
1 is effective in a case in which the objective is to assist in raising only the lower
body of the care receiver M to a standing posture.
[0067] Further, the pivot axis 32a of the arm 40 descends within the range of the upper
body height of the care receiver M during the first operation. Furthermore, the pivot
axis 32a of the arm 40 is positioned in front of the head of the care receiver M in
the initial sitting posture and behind the head of the care receiver M in the standing
posture. By positioning the pivot axis 32a of the arm 40 in the manner described above,
the assisting robot 1 assists in standing without giving discomfort to the care receiver
M.
[0068] Additionally, distance L between a line passing through the shoulder position P of
the care receiver M held by the holder 50 , with being parallel to the trunk holding
surface defined by the holder 50 for the care receiver M, and the pivot axis 32a of
the arm 40 is 230 to 290 mm. By positioning the pivot axis 32a of the arm 40 in the
manner described above, the assisting robot 1 assists in standing without giving discomfort
to the care receiver M.
[0069] Also, the time T2 of the intermediate posture of the care receiver M may be any of
the following. In the present embodiment, the time T2 of the intermediate posture
corresponds to all of the following but correspondence to at least one of the following
will suffice.
[0070] The first intermediate posture time T2 of the care receiver M is when the buttocks
of the care receiver M starts rising from the seat surface 3. The second intermediate
posture time T2 of the care receiver M is when the position in the front-rear direction
of the center of gravity G of the care receiver M enters the front-rear span F of
the ground surface in contact with the feet of the care receiver M. The third intermediate
posture time T2 of the care receiver M is when the mass supported by the holder 50
reaches a value that is equal to or greater than a predetermined percentage of the
upper body mass of the care receiver M. The fourth intermediate posture time T2 of
the care receiver M is when the rear load on the assisting robot 1 from the care receiver
M reaches a value that is equal to or less than the predetermined value. The fifth
intermediate posture time T2 of the care receiver M is when the inclination of the
upper body of the care receiver M reaches a value that is equal to or greater than
a predetermined value.
Reference Signs List
[0071] 1: assisting robot, 3: seat surface, 10: base, 30: elevator, 31: elevator main body,
32: pivot support, 32a: pivot axis, 40: arm, 50: holder, 51: trunk receiving section,
52: underarm receiving part, 80: control device, F: front-rear span of ground surface
in contact with the feet, M: the care receiver, G: center of gravity of the care receiver,
P: shoulder position, T1: time of initial sitting posture, T2: time of intermediate
posture, T3: time of standing posture, θ: angle of the trunk receiving section