JP2015000438A - Robot, positional attitude correction device, and positional attitude correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot, a positional attitude correction device, and a positional attitude correction method that can reproduce a real environment with high precision.SOLUTION: A robot 100 includes: a positional attitude acquisition part 710 for acquiring a positional attitude of a component 800 on a work table 600; a stable attitude acquisition part 720 for acquiring a stable attitude of the component 800; a positional attitude reproduction part 730 for reproducing the positional attitude of the component 800 in a virtual environment S on the basis of the information acquired by the positional attitude acquisition part 710; a reproduction state determination part 740 for determining whether an arrangement of the component 800 is proper or improper; and a positional attitude correction part 750 for selecting an attitude which is closest to the attitude of the component 800 in the virtual environment S, from among the stable attitudes acquired by the stable attitude acquisition part 720, when determined that the arrangement is improper by the reproduction state determination part 740, and for arranging the component 800 on the work table 600 by using the selected stable attitude.

Description

  The present invention relates to a robot, a position / orientation correction apparatus, and a position / orientation correction method.

  For example, a robot having an arm having at least one joint and a hand attached to the arm is known as a robot that can be used in a manufacturing process for manufacturing a precision device such as a wristwatch. In addition, before performing work in a real environment, a simulation apparatus is used to check a work process or determine a movement route of an arm (for example, see Patent Document 1).

JP 2007-326160 A

  The simulation apparatus described in Patent Document 1 is a container model arranged in a virtual environment in order to reproduce a container existing in the real environment and a plurality of works stacked in the container in the virtual environment. The work models are arranged one by one in order. At this time, the simulation apparatus appropriately determines the posture of each work model, and places each work model so that it does not overlap with the already placed work model in the determined posture. As a result, a state close to the real environment is reproduced in the virtual environment.

However, in such a simulation device, for example, the work model may be floating inside, or the work model may be stable in a posture that should not be stable, and the work model may not be in a real environment. There is. Therefore, there is a problem that a highly accurate simulation cannot be performed.
An object of the present invention is to provide a robot, a position and orientation correction apparatus, and a position and orientation correction method that can reproduce a real environment with high accuracy.

Such an object is achieved by the present invention described below.
The robot of the present invention includes an arm that performs a predetermined process on an object arranged on a reference plane;
A position and orientation acquisition unit for acquiring a position and orientation of the object on the reference plane;
A stable posture acquisition unit that acquires at least one stable posture of the object that is stably disposed on the reference plane;
Based on the information acquired by the position and orientation acquisition unit, a position and orientation reproduction unit that reproduces the position and orientation of the object on the reference plane in a virtual environment;
A reproduction state determination unit that determines whether the arrangement of the object in the virtual environment reproduced by the position and orientation reproduction unit is appropriate or inappropriate;
When it is determined that the reproduction state determination unit is inappropriate, the stable posture acquired by the stable posture acquisition unit is selected from the posture of the object in the virtual environment, A position and orientation correction unit that arranges the object on the reference plane in the selected stable posture, and
The predetermined processing is performed based on the object on the reference plane arranged by the position and orientation correction unit.
Thereby, it is possible to provide a robot that can reproduce the real environment with high accuracy.

The robot of the present invention preferably further includes an image display unit that displays the virtual environment.
Thereby, the virtual environment can be visually confirmed.
In the robot according to the aspect of the invention, the reproduction state determination unit may determine that the reproduction state determination unit is inappropriate when the object interferes with the reference plane or the object floats from the reference plane in the virtual environment. It is preferable to determine that there is.
As a result, the position and orientation of an object that cannot exist in a real environment can be effectively “inappropriate”.

In the robot according to the aspect of the invention, it is preferable that the reproduction state determination unit determines that the object is inappropriate when the target object interferes with another object in the virtual environment.
As a result, the position and orientation of an object that cannot exist in a real environment can be effectively “inappropriate”.
In the robot according to the aspect of the invention, it is preferable that the position / orientation acquisition unit sets the posture in which a vertical line passing through the center of gravity of the object intersects with a surface in contact with a reference surface of the object as the stable posture.
Thereby, a stable posture can be acquired relatively easily.

The position and orientation correction apparatus of the present invention includes a position and orientation acquisition unit that acquires the position and orientation of an object on a reference plane;
A stable posture acquisition unit that acquires at least one stable posture of the object that is stably disposed on the reference plane;
Based on the information acquired by the position and orientation acquisition unit, a position and orientation reproduction unit that reproduces the position and orientation of the object on the reference plane in a virtual environment;
A reproduction state determination unit that determines whether the arrangement of the object in the virtual environment reproduced by the position and orientation reproduction unit is appropriate or inappropriate;
When it is determined that the reproduction state determination unit is inappropriate, the stable posture acquired by the stable posture acquisition unit is selected from the posture of the object in the virtual environment, And a position / orientation correction unit that arranges the object on the reference plane in the selected stable attitude.
Accordingly, it is possible to provide a position and orientation correction apparatus that can reproduce the real environment with high accuracy.

The position and orientation correction method of the present invention acquires a position and orientation of an object on a reference plane, and acquires at least one stable orientation of the object that is stably placed on the reference plane;
Reproducing the position and orientation of the object on the reference plane in a virtual environment based on the acquired position and orientation of the object;
Determining whether the placement of the object in the reproduced virtual environment is appropriate or inappropriate;
If it is determined that the object is inappropriate, the stable posture is selected from the postures of the object in the virtual environment, and the object is moved to the reference plane with the selected stable posture. And a step of disposing the upper portion.
Accordingly, it is possible to provide a position and orientation correction method that can reproduce the real environment with high accuracy.

It is a perspective view which shows suitable embodiment of the robot of this invention. It is a figure showing the rotating shaft of the robot shown in FIG. It is a block diagram which shows the robot control part which the robot shown in FIG. 1 has. It is a figure which shows the hand with which the robot shown in FIG. 1 is mounted | worn. It is a block diagram which shows the position and orientation correction | amendment apparatus which the robot shown in FIG. 1 has. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a figure explaining the process in a position and orientation correction | amendment apparatus. It is a flowchart explaining the process in a position / orientation correction apparatus.

Hereinafter, a robot, a position / orientation correction apparatus, and a position / orientation correction method of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1 is a perspective view showing a preferred embodiment of the robot of the present invention. FIG. 2 is a diagram illustrating a rotation axis of the robot shown in FIG. FIG. 3 is a block diagram illustrating a robot control unit included in the robot illustrated in FIG. 1. FIG. 4 is a diagram showing a hand attached to the robot shown in FIG. FIG. 5 is a block diagram showing a position / orientation correction apparatus included in the robot shown in FIG. 6 to 15 are diagrams for explaining processing in the position and orientation correction apparatus. FIG. 16 is a flowchart for explaining processing in the position / orientation correction apparatus. As shown in FIGS. 6 to 15, the three axes orthogonal to each other are the X axis, the Y axis, and the Z axis, the X axis and the Y axis extend in the horizontal direction, and the Z axis extends in the vertical direction. Shall be present.
The robot 100 shown in FIG. 1 can be used in a manufacturing process for manufacturing precision equipment such as a wristwatch, for example. Such a robot 100 includes a robot main body 200, a robot control unit 900 that controls the operation of the robot main body 200, and a position and orientation correction device 700 (see FIG. 5).

(Robot body)
As shown in FIGS. 1 and 2, the robot main body 200 includes, for example, a base (base) 210 fixed to the floor, a first arm 220 connected to the base 210 via the joint mechanism 310, and a joint mechanism 320. The second arm 230 connected to the first arm 220 via the joint mechanism 330, the third arm 240 connected to the tip of the second arm 230 via the joint mechanism 330, and the third arm 240 via the joint mechanism 340. A fourth arm 250 connected to the tip, a fifth arm 260 connected to the tip of the fourth arm 250 via the joint mechanism 350, and a fifth arm 260 connected to the tip of the fifth arm 260 via the joint mechanism 360. 6 arms 270. The sixth arm 270 is provided with a hand connection portion 271, and a hand (end effector) 400 corresponding to the work to be executed by the robot 100 is attached to the hand connection portion 271. Hereinafter, the first arm 220 to the sixth arm 270 and the joint mechanisms 310 to 360 are also collectively referred to as “arm 280”.

  As shown in FIG. 2, the joint mechanism 310 rotates the first arm 220 around a rotation axis O <b> 1 perpendicular to the base 210, and the joint mechanism 320 moves the second arm 230 relative to the first arm 220. Thus, the joint mechanism 330 rotates the third arm 240 about the rotation axis O3 parallel to the rotation axis O2 with respect to the second arm 230. The joint mechanism 340 rotates the fourth arm 250 about the rotation axis O4 orthogonal to the rotation axis O3 with respect to the third arm 240, and the joint mechanism 350 causes the fifth arm 260 to move to the fourth arm 250. , The joint mechanism 360 rotates the sixth arm 270 about the rotation axis O6 orthogonal to the rotation axis O5 with respect to the fifth arm 260. Rotate.

  The joint mechanisms 310, 320, 330, 340, 350, 360 are not particularly limited. As shown in FIG. 3, the joint mechanisms 310, 320, 330, 340, 350, 360 of the present embodiment have the same configuration, and motors (drive sources) 311, 321, 331, 341, 351, 361, a speed reducer (not shown) that reduces the rotation speed of the motors 311, 321, 331, 341, 351, 361, and a position sensor 312 that detects the rotation angle of the motors 311, 321, 331, 341, 351, 361. 322, 332, 342, 352, 362. As the motors 311, 321, 331, 341, 351, 361, for example, servo motors such as AC servo motors and DC servo motors can be used. As the reducers, for example, planetary gear type reducers, A harmonic drive ("Harmonic Drive" is a registered trademark) or the like can be used. As the position sensors 312, 322, 332, 342, 352, and 362, for example, an encoder, a rotary encoder, a resolver, a potentiometer, or the like can be used. .

  The hand 400 attached to the tip of the arm 280 has a function of gripping a component (object), for example. Although the configuration of the hand 400 varies depending on the work to be performed, in the present embodiment, as illustrated in FIG. 4A, the configuration includes a first finger 410 and a second finger 420. In the hand 400, the first finger 410 is fixed, and as shown in FIG. 4B, the component 800 is grasped by moving the second finger 420 closer to or away from the first finger 410. . The movement of the second finger 420 is performed by, for example, a drive mechanism 430 that is built in the hand 400 and includes a motor 431 and a position sensor 432. As the motor 431 and the position sensor 432, those similar to the motor 311 and the position sensor 312 described above can be used.

  A force sensor may be arranged between the hand 400 having such a configuration and the hand connection portion 271. The force sensor has a function of detecting an external force applied to the hand 400, and feeds back the force detected by the force sensor to the robot control unit 900, thereby performing the operation by the robot 100 more precisely. Can do. Further, the contact of the hand 400 with an obstacle or the like can be detected by the force or moment detected by the force sensor. Therefore, an obstacle avoidance operation, an object damage avoidance operation, and the like can be performed. As such a force sensor, a known force sensor capable of detecting a force component and a moment component of each of three axes orthogonal to each other can be used.

(Robot controller)
As shown in FIG. 3, the robot control unit 900 includes a first drive source control unit 921 that controls driving of the motor 311 while obtaining feedback from the position sensor 312, and a motor 321 that obtains feedback from the position sensor 322. The second drive source control unit 922 that controls the drive, the third drive source control unit 923 that controls the drive of the motor 331 while obtaining feedback from the position sensor 332, and the motor 341 while obtaining feedback from the position sensor 342. A fourth drive source control unit 924 that controls the drive, a fifth drive source control unit 925 that controls the drive of the motor 351 while obtaining feedback from the position sensor 352, and a motor 361 that obtains feedback from the position sensor 362. A sixth drive source control unit 926 for controlling drive; While obtaining feedback from location sensor 432 has a seventh drive source controller 927 for controlling the driving of the motor 431, the. The robot controller 900 can freely move the arm 280 and the hand 400 by independently driving the motors 311, 321, 331, 341, 351, 361, and 431.

(Position and orientation correction device)
As shown in FIG. 5, the position / orientation correction apparatus 700 includes a position / orientation acquisition unit 710, a stable orientation acquisition unit 720, a position / orientation reproduction unit 730, a reproduction state determination unit 740, a position / orientation correction unit 750, and a display. Part (monitor) 760.
The position and orientation acquisition unit 710 acquires the position and orientation of the part (object) 800 on the work table (reference surface) 600 in the actual environment. When there are a plurality of parts 800 on the workbench 600, the position / orientation acquisition unit 710 acquires the position / orientation of each part 800. The position and orientation acquisition method is not particularly limited, but in this embodiment, the image data obtained by imaging the part 800 on the workbench 600 with the camera (imaging means) 711 disposed above the workbench 600 is obtained. To obtain the position and orientation of the part 800 on the work table 600. As the camera 711, a dedicated camera for acquiring the position and orientation of the component 800 may be used. For example, a monitoring camera for monitoring the robot 100 may be used. A provided camera may be used.

  The stable posture acquisition unit 720 acquires at least one stable posture of the component 800 that can be stably placed on the work table 600. The stable posture acquisition unit 720 stores data such as the outer shape and the center of gravity of the component 800 in advance, and the stable posture acquisition unit 720 uses, for example, FIG. 6, FIG. 7, and FIG. A posture as shown, that is, a posture where the vertical line L passing through the center of gravity G of the component 800 intersects the contact surface 810 with the work table 600 is acquired (calculated) as a stable posture. By defining such a posture as a stable posture, the definition of the stable posture becomes relatively simple, and the stable posture can be acquired relatively easily. However, the stable posture is not limited to the above definition as long as the component 800 can be stably arranged on the workbench 600 without wobbling. For example, as shown in FIG. 9, there are three points that are not in a straight line. As described above (points 821, 822, 823), the posture where the vertical line L passing through the center of gravity G intersects the surface defined by connecting the points 821, 822, 823 can be added to the stable posture. it can. The stable posture may be acquired using a physical operation engine such as ODE (open dynamics engine).

  The position and orientation reproduction unit 730 reproduces the position and orientation of the component 800 on the work table 600 in the virtual environment S. Specifically, as shown in FIG. 10, the position / orientation reproduction unit 730 corresponds to the work environment 600 in the virtual environment S based on the three-dimensional position and orientation of the work environment 600 stored (or acquired) in advance. A worktable model 600M is arranged, and further, a part model 800M corresponding to the part 800 is arranged in the virtual environment S based on the position and orientation of the part 800 acquired by the position and orientation acquisition unit 710. When there are a plurality of parts 800, all the part models 800M are arranged. As a result, the real environment is reproduced in the virtual environment S. The virtual environment S is displayed on the display unit 760 so that the administrator can visually confirm it.

Here, depending on the accuracy of the position / orientation acquisition unit 710 (accuracy of the camera 711) or the like, the position / orientation of the component model 800M reproduced in the virtual environment S may deviate from the position / orientation of the component 800 in the actual environment, and may be in the actual environment. There may be no state.
Therefore, the reproduction state determination unit 740 determines whether or not the part model 800M is properly arranged on the worktable model 600M. Specifically, the reproduction state determination unit 740 determines that the arrangement state that can be reproduced in the real environment is “appropriate”, and determines that the arrangement state that cannot be reproduced in the real environment is “inappropriate”. When there are a plurality of component models 800M, the appropriate / inappropriate determination is made for each component model 800M. As the “appropriate” state, for example, as shown in FIG. 11A, there is a state in which the part model 800M is arranged on the worktable model 600M in a stable posture. As shown in FIG. 11B, the part model 800M interferes with the workbench model 600M, as shown in FIG. 12A, the part model 800M floats from the workbench model 600M, 12B, there is a state in which a certain part model 800M (800M ′) interferes with another part model 800M (800M ″). According to such a method, it is possible to relatively accurately. In addition, it is possible to easily determine appropriate / inappropriate.

  When the reproduction state determination unit 740 determines that the arrangement of the component model 800M is inappropriate, the position / orientation correction unit 750 selects the closest one from the posture of the component model 800M among the stable postures acquired by the stable posture acquisition unit 720. The part model 800M is appropriately placed on the workbench model 600M with the selected stable posture. It can be said that the closest stable posture is a stable posture that can be reached by the smallest translational rotation conversion (including only one of the translational rotation and the rotation conversion). As described above, depending on the accuracy of the position / orientation acquisition unit 710, the position / orientation of the part model 800M may deviate from the position / orientation of the part 800 in the actual environment, but this deviation is not large from the current technical level. Therefore, it is considered that the closest stable posture substantially matches the position and posture of the component 800 in the real environment. Therefore, by appropriately arranging the component model 800M on the workbench model 600M with the closest stable posture, the real environment can be reproduced with high accuracy.

  For example, as shown in FIG. 13A, when the part model 800M interferes with the workbench model 600M, the position / orientation correction unit 750 displays the part model 800M. Arrangement (correction) is performed as shown in FIG. As shown in FIG. 14A, when the part model 800M is lifted from the worktable model 600M, the position / orientation correction unit 750 arranges the part model 800M as shown in FIG. 14B. . At this time, it is preferable that the position / orientation correction unit 750 corrects the center of gravity G of the component model 800M so as to coincide with the vertical direction (Z-axis direction) before and after the correction. Thereby, the movement of the component model 800M in the horizontal direction is suppressed, and the real environment can be reproduced with high accuracy.

  As shown in FIG. 15A, when the part model 800M ′ interferes with another part model 800M ″, the position / orientation correction unit 750 displays the part model 800M ′ on the surface of the workbench model 600M. 15 (b), the shift amount at this time can be appropriately set in consideration of the accuracy of the position / orientation acquisition unit 710. Thus, the actual environment Can be reproduced with high accuracy.

The configuration of the position / orientation correction apparatus 700 has been described above. Next, processing performed by the position / orientation correction apparatus 700 will be described based on the flowchart shown in FIG.
First, the stable posture acquisition unit 720 obtains the stable posture of the component 800 based on the external shape and the gravity center position of the component 800 stored in advance (S1). Next, the position and orientation acquisition unit 710 acquires the position and orientation of the component 800 on the workbench 600 (S2). Next, the position / orientation reproduction unit 730 arranges the workbench model 600M and the part model 800M in the virtual environment S, and reproduces the position / orientation of the part 800 in the real environment (S3). Next, the reproduction state determination unit 740 determines whether the arrangement of the part model 800M is appropriate or inappropriate (S4). If it is determined to be appropriate, the process is terminated. On the other hand, if it is determined to be inappropriate, the position / orientation correction unit 750 selects the nearest stable posture and places the component model 800M on the worktable model 600M in the selected stable posture (S5). The process ends here.

  According to the position / orientation correction apparatus 700 as described above, the real environment can be reproduced with high accuracy. Therefore, a subsequent simulation (for example, a simulation for confirming a work process, a route for moving the arm 280, etc.) Simulation, etc.) can be performed with higher accuracy. The robot 100 performs predetermined processing (for example, gripping) on the component 800 based on the component 800 (component model 800M) on the work table 600 (work table model 600M) corrected by the position / orientation correction apparatus 700.

As described above, the robot, the position / orientation correction apparatus, and the position / orientation correction method of the present invention have been described based on the illustrated embodiment, but the present invention is not limited to this, and the configuration of each unit has the same function. It can be replaced with one having any structure. In addition, any other component may be added to the present invention.
In the above-described embodiment, a 6-axis articulated robot having six rotation axes is used as the robot. However, the robot is not limited to this. For example, the robot has a torso and two articulated arms. It may be an arm robot or a SCARA robot (horizontal articulated robot).

  DESCRIPTION OF SYMBOLS 100 ... Robot 200 ... Robot main body 210 ... Base 220 ... 1st arm 230 ... 2nd arm 240 ... 3rd arm 250 ... 4th arm 260 ... 5th arm 270 ... 6th arm 271 …… Hand connection part 280 …… Arm 310, 320, 330, 340, 350, 360 …… Joint mechanism 311, 321, 331, 341, 351, 361 …… Motor 312, 322, 332, 342, 352, 362… ... Position sensor 400 ... Hand 410 ... First finger 420 ... Second finger 430 ... Drive mechanism 431 ... Motor 432 ... Position sensor 600 ... Worktable 600M ... Worktable model 700 ... Position Attitude correction device 710 ... Position and orientation acquisition unit 711 ... Camera 720 ... Stable posture acquisition unit 730... Position and orientation reproduction unit 740... Reproduction state determination unit 750... Position and orientation correction unit 760. 823 …… Point 900 …… Robot controller 921 …… First drive source controller 922 …… Second drive source controller 923 …… Third drive source controller 924 …… Fourth drive source controller 925 …… First 5 drive source control unit 926... 6th drive source control unit 927... 7th drive source control unit G .. center of gravity L .. vertical line O1, O2, O3, O4, O5, O6. ... virtual environment

Claims (7)

An arm for performing a predetermined process on an object arranged on a reference plane;
A position and orientation acquisition unit for acquiring a position and orientation of the object on the reference plane;
A stable posture acquisition unit that acquires at least one stable posture of the object that is stably disposed on the reference plane;
Based on the information acquired by the position and orientation acquisition unit, a position and orientation reproduction unit that reproduces the position and orientation of the object on the reference plane in a virtual environment;
A reproduction state determination unit that determines whether the arrangement of the object in the virtual environment reproduced by the position and orientation reproduction unit is appropriate or inappropriate;
When it is determined that the reproduction state determination unit is inappropriate, the stable posture acquired by the stable posture acquisition unit is selected from the posture of the object in the virtual environment, A position and orientation correction unit that arranges the object on the reference plane in the selected stable posture, and
The robot according to claim 1, wherein the predetermined process is performed based on the object on the reference plane arranged by the position and orientation correction unit.   The robot according to claim 1, further comprising an image display unit that displays the virtual environment.   The reproduction state determination unit determines that the object is inappropriate when the object interferes with the reference surface or the object floats from the reference surface in the virtual environment. The robot according to 1 or 2.   The robot according to any one of claims 1 to 3, wherein the reproduction state determination unit determines that the object is inappropriate when the target object interferes with another object in the virtual environment.   5. The robot according to claim 1, wherein the position / orientation acquisition unit sets the posture in which a vertical line passing through the center of gravity of the object intersects with a surface in contact with a reference surface of the object as the stable posture. . A position and orientation acquisition unit that acquires the position and orientation of the object on the reference plane;
A stable posture acquisition unit that acquires at least one stable posture of the object that is stably disposed on the reference plane;
Based on the information acquired by the position and orientation acquisition unit, a position and orientation reproduction unit that reproduces the position and orientation of the object on the reference plane in a virtual environment;
A reproduction state determination unit that determines whether the arrangement of the object in the virtual environment reproduced by the position and orientation reproduction unit is appropriate or inappropriate;
When it is determined that the reproduction state determination unit is inappropriate, the stable posture acquired by the stable posture acquisition unit is selected from the posture of the object in the virtual environment, And a position / orientation correction unit that arranges the object on the reference plane in the selected stable attitude. Obtaining a position and orientation of an object on a reference plane, and obtaining at least one stable orientation of the object that is stably placed on the reference plane;
Reproducing the position and orientation of the object on the reference plane in a virtual environment based on the acquired position and orientation of the object;
Determining whether the placement of the object in the reproduced virtual environment is appropriate or inappropriate;
If it is determined that the object is inappropriate, the stable posture is selected from the postures of the object in the virtual environment, and the object is moved to the reference plane with the selected stable posture. A position / orientation correction method comprising the steps of:

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