U.S. patent application number 12/912750 was filed with the patent office on 2011-05-12 for robot.
This patent application is currently assigned to KABUSHIKI KAISHA YASKAWA DENKI. Invention is credited to Takenori OKA, Manabu Okahisa.
Application Number | 20110107866 12/912750 |
Document ID | / |
Family ID | 43608800 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110107866 |
Kind Code |
A1 |
OKA; Takenori ; et
al. |
May 12, 2011 |
ROBOT
Abstract
A robot includes a base and an arm formed by a plurality of
members connected by a plurality of joints. The arm has an offset
portion where a rotation axis of a certain joint is offset from a
rotation axis of the next joint in a predetermined direction and
the rotation axis of the next joint is offset from a rotation axis
of a joint next to the next joint in a direction opposite the
predetermined direction.
Inventors: |
OKA; Takenori; (Fukuoka,
JP) ; Okahisa; Manabu; (Fukuoka, JP) |
Assignee: |
KABUSHIKI KAISHA YASKAWA
DENKI
Kitakyushu-shi
JP
|
Family ID: |
43608800 |
Appl. No.: |
12/912750 |
Filed: |
October 27, 2010 |
Current U.S.
Class: |
74/490.03 ;
74/490.04; 74/490.05 |
Current CPC
Class: |
B25J 17/00 20130101;
B25J 9/0084 20130101; Y10T 74/20317 20150115; B25J 9/06 20130101;
B25J 9/0087 20130101; Y10T 74/20323 20150115; B25J 9/046 20130101;
Y10T 74/20329 20150115 |
Class at
Publication: |
74/490.03 ;
74/490.05; 74/490.04 |
International
Class: |
B25J 18/00 20060101
B25J018/00; B25J 17/00 20060101 B25J017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2009 |
JP |
2009-257212 |
Claims
1. A robot comprising: a base; and an arm including a plurality of
members connected by a plurality of joints, wherein the arm has an
offset portion where a rotation axis of any one of the joints is
offset from a rotation axis of the next joint in a predetermined
direction and the rotation axis of the next joint is offset from a
rotation axis of a joint next to the next joint in a direction
opposite the predetermined direction.
2. The robot according to claim 1, wherein the arm includes: a
first joint configured to rotate a first member relative to the
base; a second joint configured to pivot a second member relative
to the first member; a third joint configured to rotate a third
member relative to the second member; a fourth joint configured to
pivot a fourth member relative to the third member; a fifth joint
configured to rotate a fifth member relative to the fourth member;
and a sixth joint configured to pivot a sixth member relative to
the fifth member, wherein a rotation axis of the third joint is
offset from a rotation axis of the fourth joint by a first length
in a predetermined direction, and a rotation axis of the fourth
joint is offset from a rotation axis of the fifth joint by a second
length in a direction opposite the predetermined direction.
3. The robot according to claim 2, wherein the arm further includes
a seventh joint configured to rotate the sixth member and a seventh
member.
4. The robot according to claim 2, wherein the arm further includes
a seventh joint configured to rotate on a rotation axis orthogonal
to a rotation axis of the sixth joint and to pivot a seventh member
relative to the sixth member.
5. The robot according to claim 2, further comprising: a cable
extending at least from the third joint to the fifth joint via the
fourth joint.
6. The robot according to claim 5, wherein each of the third joint,
the fourth joint, and the fifth joint is formed by an electric
motor having a hole that receives the cable.
7. The robot according to claim 6, wherein the third member
includes: a first receiving portion configured to receive the third
joint; a first connecting portion extending from the first
receiving portion in the predetermined direction; and a second
receiving portion configured to receive the fourth joint, and
wherein the cable is stored in an internal space formed by the
first receiving portion, the first connecting portion, and the
second receiving portion.
8. The robot according to claim 7, wherein the fourth member
includes: a third receiving portion configured to receive the
fourth joint; a second connecting portion extending from the third
receiving portion in the direction opposite the predetermined
direction; and a fourth receiving portion configured to receive the
fifth joint, and wherein the cable is stored in an internal space
formed by the third receiving portion, the second connecting
portion, and the fourth receiving portion.
9. The robot according to claim 1, wherein a pair of the arms are
attached to the base.
10. The robot according to claim 9, wherein the pair of arms are
attached to a body in an asymmetrical form, wherein the body
includes a base member fixed to a mounting surface, and a body
portion connected to the base member via a turning joint that turns
relative to the base member, and wherein a rotation axis of the
turning joint is offset from the base of the robot.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority under 35 U.S.C.
.sctn.119 to Japanese Patent Application No. 2009-257212, filed
Nov. 10, 2009. The contents of the application are incorporated
herein by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a robot having a plurality
of joints.
[0004] 2. Description of the Related Art
[0005] In most typical vertical articulated robots, an arm mounted
on a base includes six or seven rotary joints, and portions
provided on distal-end sides (robot-hand sides) of the joints are
rotated or turned.
[0006] The moving range of the hand of such a robot can be widened
by increasing the length of the arm. Meanwhile, if the arm is
folded so that the hand of the robot is placed in an area near the
base, it is necessary to prevent the hand from interfering with the
arm. For this reason, the moving range of the hand of the robot is
set such as not to include the area near the base.
[0007] In recent years, there has been a demand for a robot that
can perform more complicated operation and moving range. Hence, the
robot is required to operate in a manner such that the hand can be
placed both at positions sufficiently distant from the base and
positions closer to the base.
[0008] As a technique for solving this problem, Japanese Patent
Laid-Open Publication No. 2008-272883 discloses a structure for
offsetting the rotation axis of an arm in a middle portion of the
arm. According to this disclosed technique, even in a state in
which the arm is folded, a wide moving range can be ensured wile
avoiding interference between the arm portions.
SUMMARY OF THE INVENTION
[0009] The robot is required to have a more compact size while
ensuring a wider moving range. Particularly when the robot is not
in use, the arm takes a substantially straight attitude in order to
minimize an area where the arm interferes with surrounding
objects.
[0010] However, when the rotation axis of the arm is offset, as in
the technique of Patent Literature 1, even if the arm can be made
in a straight form by moving the joints of the arm, the arm
protrudes owing to the offset. This limits enhancement of the space
saving performance of the robot.
[0011] Accordingly, an object of the invention is to provide a
robot and a robot system that can enhance space-saving performance
while widening a moving range.
[0012] According to one aspect of the present invention, a robot
includes a base; and an arm including a plurality of members
connected by a plurality of joints. The arm includes an offset
portion where a rotation axis of any one of the joints is offset
from a rotation axis of the next joint in a predetermined direction
and the rotation axis of the next joint is offset from a rotation
axis of a joint next to the next joint in a direction opposite the
predetermined direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will be described in further detail
with reference to the accompanying drawings wherein:
[0014] FIG. 1 is a side view illustrating a configuration of a
robot according to a first embodiment;
[0015] FIG. 2 is a side view illustrating the configuration of the
robot of the first embodiment;
[0016] FIG. 3 is a side view illustrating a configuration of a
robot according to a second embodiment;
[0017] FIG. 4 is a side view illustrating a configuration of a
robot according to a third embodiment; and
[0018] FIG. 5 is a top view illustrating the configuration and a
moving range of the robot of the third embodiment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
First Embodiment
Overall Configuration
[0019] A first embodiment will be described below with reference to
the drawings.
[0020] As illustrated in FIG. 1, a robot system 100 according to
the first embodiment includes a seven-axis vertical articulated
robot 1, a robot controller 2, and a cable 3 that connects the
robot 1 and the robot controller 2.
[0021] The robot controller 2 is formed by a computer including a
memory, an electronic processor, and an input (all of them not
illustrated), and is connected to below-described actuators in the
robot 1 by the cable 3. The cable 3 is formed by bundling and
sheathing signal communication lines between the robot controller 2
and the actuators and power feeding lines for supplying power from
a power supply (not shown) to the actuators.
[0022] The robot 1 includes a base 10 fixed to a mounting surface
(e.g., floor or ceiling) 101, and an arm. In the arm, an arm member
(first member) 11, an arm member (second member) 12, an arm member
(third member) 13, an arm member (fourth member) 14, an arm member
(fifth member) 15, an arm member (sixth member) 16, and a flange
(seventh member 17) are connected by rotary joints (first to
seventh joints) in order from the base 10 to a leading end of the
robot 1. That is, the arm is constituted by the arm members 11 to
17 and the rotary joints.
[0023] More specifically, the base 10 and the arm member 11 are
connected by a first actuator (first joint) 11A, and the arm member
11 is rotated by driving of the first actuator 11A. The arm member
11 and the arm member 12 are connected by a second actuator (second
joint) 12A, and the arm member 12 is pivoted by driving of the
second actuator 12A.
[0024] The arm member 12 and the arm member 13 are connected by a
third actuator (third joint) 13A, and the arm member 13 is rotated
by driving of the third actuator 13A. The arm member 13 and the arm
member 14 are connected by a fourth actuator (fourth joint) 14A,
and the arm member 14 is pivoted by driving of the fourth actuator
14A.
[0025] The arm member 14 and the arm member 15 are connected by a
fifth actuator (fifth joint) 15A, and the arm member 15 is rotated
by driving of the fifth actuator 15A. The arm member 15 and the arm
member 16 are connected by a sixth actuator (sixth joint) 16A, and
the arm member 16 is pivoted by driving of the sixth actuator
16A.
[0026] The arm member 16 and the flange 17 are connected by a
seventh actuator (seventh joint) 17A, and the flange 17 and an end
effecter (not shown), such as a hand, which is attached to the
flange 17 are pivoted by driving of the seventh actuator 17A.
[0027] As illustrated in FIG. 1, the arm member 13 includes a
receiving portion (receiving portion A) 20A that receives the third
actuator 13A, a connecting portion (connecting portion A) 20B
obliquely extending from the receiving portion 20A to the upper
right side of the figure (in the R-direction and a direction
towards the leading end), and a receiving portion (receiving
portion B) 20C that receives the fourth actuator 14A. The receiving
portion 20A, the receiving portion 20C, and the connecting portion
20B form a continuous internal space, where the cable 3 is
stored.
[0028] The arm member 14 includes a receiving portion (receiving
portion A) 21A that receives the fourth actuator 14A, a connecting
portion (connecting portion B) 21B obliquely extending from the
receiving portion 21A to the upper left side of the figure (in the
L-direction and a direction towards the leading end), and a
receiving portion (receiving portion D) 21C that receives the fifth
actuator 15A. The receiving portion 21A, the receiving portion 21C,
and the connecting portion 21B form a continuous internal
space.
[0029] That is, the receiving portion 20A, the receiving portion
20C, the connecting portion 20B, the receiving portion 21A, the
receiving portion 21C, and the connecting portion 21B correspond to
the offset portion.
[0030] Each of the first to seventh actuators 11A to 17A is formed
by a servo motor with built-in reduction gears. The servo motor has
a hole through which the cable 3 can extend. The first to seventh
actuators 11A to 17A are connected to the robot controller 2 by the
cable 3.
[0031] When the robot 1 takes an attitude such that rotation axes
A1, A3, and A5 (referred to as rotation axes in the rotating
direction) are perpendicular to the mounting surface 101 (a state
illustrated in FIG. 1), rotation axes A2, A4, A6, and A7 (rotation
axes in the pivot direction) are at an angle of 90 degrees to the
rotation axes in the rotating direction. Further, the rotation axis
A6 is at an angle of 90 degrees to the rotation axis A7.
[0032] The rotation axis A1 of the first actuator 11A and the
rotation axis A3 of the third actuator 13A are substantially
aligned with each other. Also, the rotation axis A1 and the
rotation axis A3 are orthogonal to the rotation axis A2 of the
second actuator 12A.
[0033] The rotation axes A1 and A3 do not intersect the rotation
axis A4 of the fourth actuator 14A, and are offset from the
rotation axis A4 by a length d1 in a direction horizontal to the
mounting surface 101 (in a R-direction with reference to the
rotation axis A3).
[0034] In other words, the offset refers to a state in which a
rotation axis different from a rotation axis at a base end is
shifted from the rotation axis at the base end in the orthogonal
direction when the robot or the arm takes an attitude such that the
projection area thereof on the mounting surface is the
smallest.
[0035] Further, the rotation axis A4 does not intersect the
rotation axis A5 of the fifth actuator 15A, and is offset from the
rotation axis A5 by a length d2 in the direction horizontal to the
mounting surface 101 (in the rightward direction of the figure with
reference to the rotation axis A4).
[0036] Therefore, the rotation axis A3 and the rotation axis A5 are
offset by a length |d1-d2| in the direction horizontal to the
mounting surface 101 (in the rightward direction of the figure with
reference to the rotation axis A3).
[0037] In the first embodiment, the length d1 is set to be larger
than the length d2 (that is, d1>d2). The width of the arm member
13 is larger than the width of the arm member 15.
[0038] The base 10 has a cable insertion hole (not shown). As
illustrated in FIG. 2, the cable 3 passes, in order, through the
interior of the base 10, the hole of the first actuator 11A, the
arm member 11, the hole of the second actuator 12A, the arm member
12, the hole of the third actuator 13A, the receiving portion 20A,
the connecting portion 20B, the receiving portion 20C, the hole of
the fourth actuator 14A, the receiving portion 21A, the connecting
portion 21B, the receiving portion 21C, the hole of the fifth
actuator 15A, the arm member 15, the hole of the sixth actuator
16A, the arm member 16, and the hole of the seventh actuator 17A.
Further, the cable 3 is connected to the end effecter (not shown)
via a hole of the flange 17.
[0039] Since the robot system 100 of the first embodiment has the
above-described configuration, when the robot system 100 operates
with the flange 17 being placed near the base 10 or the arm member
11, in a state in which the fourth actuator 14A is greatly rotated,
as illustrated in FIG. 2, the rotation axis A3 and the rotation
axis A5 are offset from each other by the sum of the length d1 and
the length d2 (that is, d1+d2), which increases the offset amount
between the rotation axis A3 and the rotation axis A5. For this
reason, even when the fourth actuator 14A is bent to obtain an
attitude such that the rotation axis A3 and the rotation axis A5
become substantially parallel to each other, it is possible to
prevent the arm member 13 and the arm member 15 from touching and
interfering each other and to allow the flange 17 to reach a lower
position near the arm member 11.
[0040] In contrast, during a standby state of the robot system 100,
the robot 1 is operated so that the rotation axis A1, the rotation
axis A3, and the rotation axis A5 become perpendicular to the
mounting surface 101. This can minimize the amount of protrusion of
the robot 1 in the direction horizontal to the mounting surface
101. In this case, the offset amount of the rotation axes A1 and A3
from the rotation axis A4 is limited to the length d1.
[0041] In other words, the offset amount corresponding to d1+d2 can
be obtained in the state where the fourth actuator 14A is bent, and
the offset amount can be limited to d1 (d1<d1+d2) in the standby
state. Thus, a wide moving range of the flange 17 can be ensured by
the offset, and moreover space saving can be achieved.
[0042] The cable 3 passes through the hole of the third actuator
13A, is gently bent in the connecting portion 20B, passes through
the hole of the fourth actuator 14A, is gently bent in the
connecting portion 21B, and is then guided to the hole of the fifth
actuator 15A. Therefore, even if the angle between the arm member
13 and the arm member 14 is made more acute by greatly rotating the
fourth actuator 14A, the curvature of the cable 3 can be limited to
a relatively small value. Hence, it is possible to reduce damage to
the cable 3 due to the increase in curvature of the cable 3.
[0043] In the first embodiment, the fifth actuator 15A rotates the
arm member 15, the sixth actuator 16A pivots the arm member 16, and
the seventh actuator 17A rocks the flange 17 at an angle of 90
degrees to the pivot direction of the arm member 16. Hence, unlike
the case in which the seventh actuator 17A rotates the flange 17,
it is possible to prevent an out-of-control point (singular point)
from being caused by overlapping of the rotation axis A5 and the
rotation axis A7. For this reason, it is unnecessary to perform an
operation for avoiding the singular point in the attitude such that
the fourth actuator 14A is bent (state of FIG. 2). This increases
the degree of flexibility in operation of the robot 1.
Second Embodiment
[0044] Next, a second embodiment will be described. As illustrated
in FIG. 3, a robot system 200 of the second embodiment is different
from the robot 1 of the first embodiment only in an attachment
direction of a seventh actuator 27A (seventh joint) and a flange
27. Therefore, in the following description, for convenience of
explanation, redundant descriptions are appropriately omitted, and
like components are denoted by like reference numerals.
[0045] In the second embodiment, an arm member 16 is connected to
the flange 27 by the seventh actuator 27A, and the flange 27 and an
end effecter (not shown), such as a hand, attached to the flange 27
are rotated by driving of the seventh actuator 27A.
[0046] Since the robot system 200 of the second embodiment has the
above-described configuration, in contrast to the robot 1 of the
first embodiment, it is necessary to avoid a singular point caused
when a fourth actuator 14A is bent, but it is possible to easily
rotate the end effecter attached to the flange 27 by simply driving
the seventh actuator 27A. Thus, the second embodiment is suitable
for an application in which the end effecter is rotated.
Third Embodiment
[0047] Next, a third embodiment will be described. As illustrated
in FIGS. 4 and 5, the third embodiment is different from the first
embodiment in that the base adopted in the first embodiment is
removed and the body is provided with a pair of (two) arms 400
having a structure similar to that of the arm of the robot 1.
Therefore, descriptions overlapping with the first embodiment are
appropriately omitted, and like components are denoted by like
reference numerals.
[0048] In a robot system 300 of the third embodiment, two arms 400
are attached to a body 301 (corresponding to the base) fixed to a
mounting surface 101.
[0049] The body 301 includes a base portion 301A fixed to the
mounting surface 101, and a turning body portion (main body) 301B
that turns relative to the base portion 301A via an actuator
301C.
[0050] The turning body portion 301B obliquely extends upward (to
the upper right of FIG. 4) from the actuator 301C, and has an
opening where the pair of arms 400 can be attached.
[0051] A rotation axis Ab of the actuator 301C is offset from
rotation axes A1 of first actuators 11A in the arms 400 by a length
d3 in a direction horizontal to the mounting surface 101
(R-direction with reference to the rotation axis Ab).
[0052] In the third embodiment, the arms 400 are attached to the
turning body portion 301B in a manner such that the rotation axes
A1 of the respective first actuators 11A are arranged on the same
straight line (the orientations of the arms 400 can be changed
appropriately). That is, the turning body portion 301B also
functions as a bases for both of the arms 400. A robot controller
302 is connected to the arms 400 by a cable 303 so that the
actuators of the arms 400 operate according to commands from the
robot controller 302.
[0053] Since the robot system 300 of the third embodiment has the
above-described configuration, it is possible to enlarge the moving
range where the pair of arms 400 cooperate near the body, for
example, during assembly of mechanical products. This achieves
further space saving.
[0054] Further, the turning body portion 301B obliquely extends
upward and the pair of arms 400 are attached thereto. Thus, the
offset between the rotation axis Ab and the rotation axis A1 allows
the flanges 17 of the arms 400 to be moved to farther positions by
rotating the actuator 301C.
[0055] In addition, ends of the arms 400 can reach even a space
formed near the base portion 301A and below the turning body
portion 301B. Therefore, operation can be performed utilizing the
space below the turning body portion 301B, and this achieves
further space saving.
[0056] While the embodiments of the present invention have been
described above, the robot system of the present invention is not
limited to the above embodiments, and appropriate modifications can
be made without departing from the scope of the present
invention.
[0057] For example, while the robot of the first embodiment is
attached to the body in the third embodiment, the arm attached to
the body may be similar to the arm adopted in the robot system 200
of the second embodiment.
[0058] While the robot has seven joints in the above embodiments,
it may have three joints. For example, the structures other than
the third to fifth actuators 13A, 14A, and 15A and the arm members
13 to 15 in the first embodiment may be removed from the robot.
* * * * *