Robot-mounted moving device, system, and machine tool
A system includes a machine tool 10 , a robot 25 having a camera 31 , and a transfer device 35 having the robot 25 mounted thereon, and an identification figure is arranged in a machining area of the machine tool 10.
1. A robot-mounted moving device movable around a machine tool,
the robot-mounted moving device having stored therein a reference identification position as information associated with a reference device position,
the reference device position being a position of the robot-mounted moving device for performing an operation of extracting a target from inside of the machine tool or an operation of attaching the target into the machine tool,
the reference identification position being a position of an identification figure arranged within the machine tool on a first axis and a second axis set in a plane parallel to the identification figure at the reference device position, wherein the identification figure has a set position within the machine tool and the robot-mounted moving device moves relative to the identification figure,
the robot-mounted moving device comprising:
a robot having (i) a camera, (ii) a hand unit configured to grip a workpiece or a tool, (iii) a second arm unit to which the hand unit is movably coupled, and (iv) a first arm unit to which the second arm unit is movably coupled;
a control unit controlling a position of the hand unit of the robot; and
a moving unit configured to be movable and having the robot mounted thereon,
wherein, at a current device position different from the reference device position, the control unit controls, based on a difference between the reference identification position and the current identification position which is a position of the identification figure in the plane when an image of the identification figure is captured by the camera at the current device position, movement of the hand unit of the robot to an operating pose by means of (a) movement on the first axis in the plane, (b) movement on the second axis in the plane, and (c) rotational movement in the plane.
2. A system comprising:
a machine tool performing predetermined machining on a workpiece;
a robot having a camera for image capturing and an end effector acting on the workpiece, and performing an operation to the machine tool;
a transfer device having the robot mounted thereon, and configured to be movable to an operating position set with respect to the machine tool; and
a controller configured to, in accordance with an operation program containing a predetermined operation command, bring the robot in sequence into an operation starting pose, an image capturing pose for causing the camera to face an identification figure for pose compensation arranged in the machine tool and capture an image of the identification figure, and one or more operating poses for causing the end effector to act on the workpiece,
the operation starting pose, the image capturing pose, and the one or more operating poses being set in advance by performing a teaching operation to the robot,
the identification figure being formed on a predetermined plane and arranged in a machining area of the machine tool,
the controller being configured to:
in the teaching operation,
cause the camera to capture a reference image of the identification figure with the robot in the image capturing pose, and
in actual operation of the robot in accordance with the operation program,
estimate, based on the reference image and a current image of the identification figure captured by the camera after the robot is brought into the image capturing pose from the operation starting pose when the transfer device is at the operating position, positional error amounts of the camera in a first axis and a second axis and a rotational error amount of the camera around a third axis between a current pose of the robot and a pose of the robot in the teaching operation, the first axis and the second axis being orthogonal to each other and set in a plane parallel to the identification figure, the third axis being orthogonal to the first axis and the second axis,
calculate a compensation amount for the end effector in the one or more operating poses based on the estimated error amounts, and
compensate a position of the end effector in each of the one or more operating poses based on the calculated compensation amount.
3. The system of claim 2 , wherein:
the first axis and the second axis are respectively an x-axis and a y-axis of an x-axis and y-axis coordinate system corresponding to the pose of the robot in the teaching operation;
the third axis is a z-axis orthogonal to the x-axis and the y-axis; and
the controller is configured to:
estimate positional error amounts Δx, Δy of the camera in the x-axis and y-axis coordinate system and a rotational error amount Δrz of the camera around the z-axis,
calculate, based on the estimated positional error amounts Δx, Δy and rotational error amount Δrz, translational error amounts t x , t y of the end effector between a current position of the end effector and a position of the end effector in the teaching operation in the x-axis and y-axis coordinate system in accordance with an equation:
[
t
x
t
y
]
=
[
x
′
y
′
]
-
[
cos
Δ
r
z
-
sin
Δ
r
z
sin
Δ
r
z
cos
Δ
r
z
]
[
x
+
Δ
x
y
+
Δ
y
]
where x and y indicate a position of the camera in the teaching operation in the x-axis and y-axis coordinate system, and x′ and y′ indicate a current position of the camera in an x′-axis and y′-axis coordinate system corresponding to the current pose of the robot, and
compensate a position of the end effector in each of the one or more operating poses based on the calculated translational error amounts t x , t y and the rotational error amount Δrz.
4. The system of claim 2 , wherein the transfer device is an automatic guided vehicle controlled by the controller and is configured to, under control by the controller, move to the operating position set with respect to the machine tool.
5. The system of claim 2 , wherein the identification figure has a matrix structure having a plurality of pixels arranged two-dimensionally.
6. The system of claim 2 , wherein the controller is configured to, after calculating the estimated positional error amounts of the camera in the first axis and the second axis and the estimated rotational error amount of the camera around the third axis,
compensate the image capturing pose of the robot based on the estimated positional error amounts in the first axis and the second axis and the estimated rotational error amount around the third axis and bring the robot into the compensated image capturing pose,
thereafter, cause the camera to capture the current an image of the identification figure,
estimate, based on the current image of the identification figure and the reference image, a positional error amount of the camera in the third axis, a rotational error amount of the camera around the first axis, and a rotational error amount of the camera around the second axis between a current pose of the robot and a pose of the robot in the teaching operation, and
compensate a position of the end effector in each of the one or more operating poses based on the estimated positional error amounts in the first axis, the second axis, and the third axis and the estimated rotational error amounts around the first axis, the second axis, and the third axis.
7. A system comprising:
a machine tool performing predetermined machining on a workpiece;
a robot having a camera for image capturing and an end effector acting on the workpiece, and performing an operation to the machine tool;
a transfer device having the robot mounted thereon, and configured to be movable to an operating position set with respect to the machine tool; and
a controller configured to, in accordance with an operation program containing a predetermined operation command, bring the robot in sequence into an operation starting pose, an image capturing pose for causing the camera to capture an image of an identification figure for pose compensation arranged in the machine tool, and one or more operating poses for causing the end effector to act on the workpiece,
the operation starting pose, the image capturing pose, and the one or more operating poses being set in advance by performing a teaching operation to the robot,
the identification figure being formed on a predetermined plane and arranged in a machining area of the machine tool,
the controller being configured to:
in the teaching operation,
cause the camera to capture a reference image of the identification figure with the robot in the image capturing pose, and
in actual operation of the robot in accordance with the operation program,
estimate, based on the reference image and a current an image of the identification figure captured by the camera after the robot is brought into the image capturing pose from the operation starting pose when the transfer device is at the operating position, positional error amounts of the camera in a first axis, a second axis, and a third axis and rotational error amounts of the camera around the first axis, the second axis, and the third axis between a current pose of the robot and a pose of the robot in the teaching operation, the first axis and the second axis being orthogonal to each other and set in a plane parallel to the identification figure, the third axis being orthogonal to the first axis and the second axis, and
compensate a position of the end effector in each of the one or more operating poses based on the estimated positional error amounts and rotational error amounts.
8. The system of claim 7 , wherein the controller is configured to carry out a process of calculating, based on the reference image, an image-capturing camera position p ideal camera_teach in the teaching operation in a teaching-operation robot coordinate system corresponding to the robot in the teaching operation, a process of calculating, based on the current image of the identification figure captured in the actual operation, an image-capturing camera position P ideal camera_curr in the actual operation in the teaching-operation robot coordinate system, a process of estimating, based on the calculated image-capturing camera position p ideal camera_teach ideal and image-capturing camera position p ideal camera_curr in the teaching-operation robot coordinate system, positional error amounts of the camera in the first axis, the second axis, and the third axis and rotational error amounts of the camera around the first axis, the second axis, and the third axis in an actual-operation robot coordinate system corresponding to the robot in the actual operation, and a process of compensating a position of the end effector in each of the one or more operation poses based on the estimated positional error amounts and rotational error amounts.
9. The system of claim 8 , wherein the controller is configured to:
after calculating the image-capturing camera position p ideal camera_teach ideal and the image-capturing camera position p ideal camera_curr in the teaching-operation robot coordinate system,
carry out a process of calculating, based on teaching-operation camera angles rx ideal camera_teach , ry ideal camera_teach , rz ideal camera_teach in the teaching-operation coordinate system and current camera angles rx ideal camera_curr ry ideal camera_curr , rz ideal camera_curr in the teaching-operation coordinate system, a difference between them to calculate, with the first axis, the second axis, and the third axis respectively designated as an x-axis, a y-axis, and a z-axis, rotational error amounts Δrx, Δry, and Δrz around the x-axis, the y-axis, and the z-axis and calculating, based on the calculated rotational error amounts Δrx, Δry, and Δrz, a rotation matrix R curr ideal between the teaching-operation robot coordinate system and the actual-operation robot coordinate system as the rotational error amounts of the camera in the actual-operation robot coordinate system, a process of calculating a translation matrix T curr ideal from the teaching-operation robot coordinate system to the actual-operation robot coordinate system as the positional error amounts of the camera in the actual-operation robot coordinate system, a process of calculating a compensation amount M curr ideal based on the rotation matrix R curr ideal and the translation matrix T curr ideal curr, and a process of calculating a compensated position p curr goal of the end effector in each of the one or more operating poses based on the compensation amount M curr ideal .
10. The system of claim 9 , wherein the controller is configured to calculate the rotation matrix R curr ideal , the translation matrix T curr ideal , the compensation amount M curr ideal , and the compensated position p curr goal in accordance with equations below:
R
c
u
r
r
i
d
e
a
l
=
[
cos
Δ
r
z
-
sin
Δ
r
z
0
sin
Δ
r
z
cos
Δ
r
z
0
0
0
1
]
[
cos
Δ
r
y
0
sin
Δ
r
y
0
1
0
-
sin
Δ
r
y
0
cos
Δ
r
y
]
[
1
0
0
0
cos
Δ
r
x
-
sin
Δ
r
x
0
sin
Δ
r
x
cos
Δ
r
x
]
T
c
u
r
r
i
d
e
a
l
=
P
c
u
r
r
c
a
m
e
r
a
-
c
u
r
r
-
R
c
u
r
r
i
d
e
a
l
·
P
i
d
e
a
l
c
a
m
e
r
a
-
c
u
r
r
M
c
u
r
r
i
d
e
a
l
=
[
R
c
u
r
r
i
d
e
a
l
T
c
u
r
r
i
d
e
a
l
0
1
]
[
P
c
u
r
r
g
o
a
l
1
]
=
M
c
u
r
r
i
d
e
a
l
·
[
P
ideal
goal
1
]
where p goal ideal is a position of the end effector in the teaching operation in the teaching-operation robot coordinate system.
11. A machine tool for machining a workpiece, configured such that:
a transfer device has a robot mounted thereon and is configured to transfer the robot to a first position to allow the robot to hold the workpiece, the robot having a camera for capturing a current image including an identification figure arranged in the machine tool, and an end effector acting on the workpiece;
the camera captures a current image including the identification figure arranged in the machine tool after the transfer device transfers the robot to the first position;
a second position of the end effector in an X-axis and a Y-axis in a three-dimensional space defined by the X-axis, the Y-axis, and a Z-axis is compensated by linearly and rotationally moving the end effector based on positional information of the identification figure in the current image of the identification figure and a reference image of the identification figure; and
the end effector is caused to act on the workpiece in the machine tool after the second position is compensated,
wherein the identification figure is arranged at a set position in a machining area of the machine tool.