JP2015100874A - Robot system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot system capable of easily adjusting an attitude intuitionally and teaching the gripping attitude information more precisely.SOLUTION: A robot system comprises: a robot 6 for gripping a workpiece; and a teaching device 2 for teaching the robot 6 the gripping position information of the workpiece. The teaching device 2 receives the first gripping position of the workpiece by the robot 6 in a first coordinate system and a second gripping position of the workpiece by the robot 6 in a second coordinate system thereby to teach the robot the gripping position information.

Description

  The present invention relates to a robot system.

  When operating an industrial robot, for example, a deburring robot for a workpiece, it is necessary to create an operation program for operating the robot (hereinafter referred to as a “teaching program”). As a method for creating this teaching program, for example, in an actual deburring line, there are an online system that uses a robot as an actual machine and an offline system that uses a computer simulation to perform outside the actual line. .

Of these, in the offline method, a 3D model of the work environment including the robot model and a 3D model of the work are created and displayed on the display screen, and teach points (teaching points) that are the work points on the display screen. (Also referred to as “also called”), and an operation program is created by determining the passing order of each teach point.
In the case of such a simulation method, there is an advantage that it is not necessary to stop the deburring line, and that it is possible to easily set the operation in accordance with the actual work environment.

  By the way, as a programming language for controlling an industrial robot, there are a compiler type and an interpreter type. In any type of robot language, a user who is an operator edits a program language with reference to a screen on which these languages are displayed. That is, since the work contents performed by the robot are displayed as a program list in the robot language, there is a problem that it is difficult to grasp the actual work contents, and special knowledge and experience regarding the program are required.

  Conventionally, as shown in Japanese Patent Application Laid-Open No. 2004-133620, such a problem is easily displayed visually by displaying, creating and editing a program used for teaching an industrial robot having an interface function with a user. Techniques to do are disclosed.

JP 2012-22546 A

However, the conventional techniques described above have the following problems. According to Patent Document 1, an operation program for causing a robot to perform a processing operation on a machine tool of a processing-related object is created offline, and the processing program is visually displayed as disclosed in Patent Document 1.
On the other hand, machining workpieces flowing in a line may be of a single type or shape, or may be different, and each time the machining workpiece is changed, the program correction is sequentially performed on the personal computer in the tool coordinate system or part coordinate system. Since either one of the coordinate systems is used to teach the teaching point, there is a risk of lack of accuracy.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A robot system according to this application example includes a robot that grips a workpiece, and a teaching device that teaches the robot about gripping posture information of the workpiece, and the teaching device is in a first coordinate system. The robot is instructed of the grip posture information by receiving a first grip posture of the workpiece by the robot and a second grip posture of the workpiece by the robot in a second coordinate system. .

  According to this application example, when teaching the workpiece gripping posture information to the robot that grips the workpiece, the first gripping posture determined in the first coordinate system and the second gripping posture determined in the second coordinate system Since the final gripping posture information is determined by accepting, it is easy to intuitively adjust the posture, and the gripping posture information can be taught more accurately.

  Application Example 2 In the robot system according to the application example, the teaching device includes a display unit that displays an input reception screen for receiving the first gripping posture and the second gripping posture, The input reception screen includes a first input unit that inputs the first gripping posture, a second input unit that inputs the second gripping posture, the input first gripping posture, and the second gripping And a gripping posture display unit that displays a gripping posture of the workpiece by the robot based on the posture.

  According to this application example, the first gripping posture determined in the first coordinate system and the second gripping posture determined in the second coordinate system are superimposed and visually displayed, and the final gripping posture is displayed. Information can be easily determined.

  Application Example 3 In the robot system according to the application example, the first coordinate system is a parts coordinate system based on an origin provided on the workpiece.

  According to this application example, the first coordinate system can be easily determined.

  Application Example 4 In the robot system according to the application example, the second coordinate system is a hand coordinate system based on an origin provided in the hand of the robot.

  According to this application example, the second coordinate system can be easily determined.

  Application Example 5 In the robot system according to the application example described above, the teaching apparatus receives the second holding posture after receiving the first holding posture.

  According to this application example, since the second gripping posture in the hand coordinate system is determined after the first gripping posture in the part coordinate system is determined, it is easy to intuitively adjust the gripping posture.

The figure which shows the robot system structural example which concerns on this embodiment. The figure which shows the hand which concerns on this embodiment. The figure which shows the detailed robot system structural example which concerns on this embodiment. The figure which showed the example of the input reception screen which concerns on this embodiment. The flowchart for demonstrating the process which concerns on this embodiment. A specific example of a situation used for explaining a flowchart. The flowchart for demonstrating the process which concerns on this embodiment.

  Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.

1. FIG. 1 is a diagram illustrating a configuration example of a robot system according to the present embodiment. FIG. 2 is a diagram illustrating the hand 12 according to the present embodiment. First, the method of this embodiment will be described. As will be described later with reference to FIG. 1, the present embodiment relates to a method for teaching gripping posture information of a robot control device or the like having an arm and a hand (grip unit) provided at the tip of the arm. In such an industrial robot, a work (an object to be processed) placed on a pallet or the like is processed by operating an arm and a hand. As specific examples of processing, grasping, processing, changing the direction, moving, and the like can be considered.

  When processing an industrial robot, it is necessary to set a series of work contents (hereinafter referred to as scenarios as appropriate). As an example of a scenario, an example in which a workpiece is held and then placed with a specific surface facing down can be considered. In addition, a scenario may be assumed in which a workpiece is gripped with the right hand, then is moved to the left hand, and a part is attached to a specific position of the workpiece with the right hand.

However, even if a scenario is set, it is not easy for the robot to perform processing more accurately.
For example, when teaching a gripping method of a workpiece, if a gripping point (x, y, z) of a hand and a rotation (α, β, γ) around the xyz axis are input by numerical values or sliders, Is graphically displayed at the specified position and orientation, and teaches the grip position and grip posture information while viewing the figure. In the figure, the work environment may be displayed in a global coordinate system, or the object may be displayed in the coordinate system of the object such as a workpiece. I want to teach the position and orientation of the hand in the coordinate system, but it is difficult to intuitively understand the movement when multiple axes rotate.

  Therefore, the present applicant proposes a method for determining a more accurate gripping posture according to a scenario. In the above example, the gripping posture information taught in the parts coordinate system (first coordinate system) and the gripping posture information taught in the hand coordinate system (second coordinate system) are combined to obtain the final gripping posture information. To decide. Specifically, after rotating around the xyz axis to roughly determine the direction of the hand 12 shown in FIG. 2, fine adjustment is performed. That is, after the hand 12 is rotated around the xyz axis at a specified angle, rotation is input (specified) with respect to the attitude (axis) of the hand 12. By doing so, the grip posture information can be taught more accurately. The hand coordinate system is a coordinate system based on the position of the robot's hand, and the part coordinate system is a coordinate system based on the direction in which the workpiece is facing.

  Here, the rotation matrix around the axis will be described. The rotation matrix around the axis is expressed by the following equation (1) when the point (x, y, z) is rotated by an angle α around the x axis, an angle β around the y axis, and an angle γ around the z axis. Is done.

図２のようにハンド１２の前をｚ軸、指の開閉方向をｘ軸とした場合に、回転後のベクトルは、ハンド１２の前方向は式（１）の（ｘ，ｙ，ｚ）に（０，０，１）、回転後のハンド１２の指の開閉方向は式（１）の（ｘ，ｙ，ｚ）に（１，０，０）を代入すれば求められる。

As shown in FIG. 2, when the front of the hand 12 is the z-axis and the opening / closing direction of the finger is the x-axis, the vector after the rotation is represented by (x, y, z) in the expression (1). (0, 0, 1), the opening / closing direction of the finger of the hand 12 after rotation can be obtained by substituting (1, 0, 0) for (x, y, z) in the equation (1).

  A rotation matrix around an arbitrary axis is expressed by the following equation (2) when the angle θ is rotated around the vector A (a, b, c).

式（１）で回転後に手首の周りに回転させて微調整しようとした場合、式（１）で計算したハンド１２の前方向のベクトルをＡ、ユーザーが入力した角度を角度θとして式（２）でハンド１２の指の開閉方向が計算できる。以下、ロボットシステム構成例を説明し、把持姿勢情報の教示方法を、フローチャートを用いて説明する。

In the case of trying to finely adjust by rotating around the wrist after the rotation in Expression (1), the forward vector of the hand 12 calculated in Expression (1) is A, and the angle input by the user is the angle θ. ) To calculate the opening / closing direction of the finger of the hand 12. Hereinafter, a configuration example of the robot system will be described, and a teaching method of gripping posture information will be described using a flowchart.

2. Robot System Configuration Example A configuration example of a robot system including the robot control apparatus according to the present embodiment will be described with reference to FIG. The robot system includes a teaching device 2, an imaging device 4, and a robot 6. However, the robot system is not limited to the configuration of FIG. 1, and various modifications such as omitting some of these components or adding other components are possible. The robot 6 has an arm 10 and a hand 12 and performs processing in accordance with an operation instruction from the teaching device 2. For example, processing is performed on the workpiece placed on the pallet 14. The imaging device 4 is provided, for example, at a position where the workpiece can be photographed (may be directly above the pallet or attached to the hand 12 of the robot 6), and mainly photographs the workpiece. Then, information relating to the position and posture of the workpiece is detected from the information of the captured image. For example, the detected information may be sent to the teaching device 2 or the like, or may be sent directly to the robot 6. Further, since it is only necessary to be able to detect information related to the position, posture, etc. of the workpiece, a method other than acquisition of a captured image by the imaging device 4 (for example, three-dimensional scanning using a laser) may be used.

Next, the teaching device 2 will be described with reference to FIGS. 3 and 4.
FIG. 3 is a diagram illustrating a detailed configuration example of the robot system according to the present embodiment. As shown in FIG. 3, the teaching apparatus 2 has the same configuration as a general computer, and includes a storage unit 16, a processing unit 18, a display unit 20, and an external I / F unit 22.

  The storage unit 16 stores a database and serves as a work area for the processing unit 18 and the like, and its function can be realized by a memory such as a RAM or an HDD (hard disk drive). The storage unit 16 includes a work database 24 (hereinafter referred to as DB as appropriate) and a robot DB 26. The robot DB 26 includes an arm DB 28 and a hand DB 30. When the robot includes a plurality of arms, the arm DB 28 and the hand DB 30 may be plural.

  The work DB 24 stores information such as the size, shape, and posture of the work.

  The robot DB 26 stores data related to the robot. Specifically, the arm DB 28 stores the shape of the arm, the movable range, and the like, and the hand DB 30 stores information such as the shape and size of the hand. However, the memory | storage part 16 is not limited to the structure of FIG. 3, Various deformation | transformation implementations, such as abbreviate | omitting some of these components and adding another component, are possible.

  The processing unit 18 performs various processes based on data from the storage unit 16, information from the imaging device or robot received by the external I / F unit 22, and the like. The function of the processing unit 18 can be realized by hardware such as various processors (CPU and the like), ASIC (gate array and the like), a program, and the like.

  The processing unit 18 includes a work position calculation unit 32, an image processing unit 34, and a grip pattern information acquisition unit 36. The processing unit 18 is not limited to the configuration shown in FIG. 3, and various modifications such as omitting some of these components or adding other components are possible.

  The work position calculation unit 32 calculates the position of the work. For example, the work position is calculated using data acquired from the imaging device 4 in the external I / F unit 22.

  The image processing unit 34 acquires captured image information from the imaging device 4 and performs various image processing. Although the image processing unit 34 is provided in the processing unit 18 of the teaching device 2 here, the present invention is not limited to this. The image processing unit may be built in the imaging device 4.

  The grip pattern information acquisition unit 36 acquires grip pattern information that can execute an operation instruction based on information stored in the database of the storage unit 16. A specific acquired grip pattern group will be described later.

  The display unit 20 is for displaying various display screens, and can be realized by, for example, a liquid crystal display or an organic EL display.

  The external I / F unit 22 is an interface for performing input from the user to the teaching device 2 and receiving information from the imaging device 4 and the robot 6. The input from the user may be configured from a switch, button, keyboard, mouse or the like.

  As described above, the imaging device 4 is provided, for example, at a position where a workpiece can be photographed, and mainly photographs the workpiece. In the present embodiment, the captured image information is transmitted as it is to the teaching device 2, but the present invention is not limited to this. For example, a part of the processing unit 18 of the teaching device 2 (for example, the image processing unit 34) may be provided in the imaging device 4. In this case, information after image processing is performed on the captured image is output.

  The robot 6 includes a control unit 38 in addition to the arm 10 and the hand 12. The control unit 38 receives information from the teaching device 2 and controls each unit (arm 10, hand 12, etc.) of the robot 6.

3. Gripping posture information teaching method Next, a gripping posture information teaching method will be described. Specifically, the flow of processing will be described using a flowchart.
FIG. 4 is a diagram illustrating an example of an input reception screen according to the present embodiment. The teaching device 2 displays an input reception screen as shown in FIG. The input reception screen is a screen for inputting the gripping point and posture of the hand 12. The input reception screen includes a first input unit D that prompts input of a gripping point and posture of “input of coordinates and orientation”, a second input unit E that prompts input of rotation around “Position A” of “fine adjustment”, and a workpiece And a gripping posture display unit F that graphically displays a positional relationship between the hand 12 and the hand 12.

  The work and the hand 12 are displayed in the xyz-axis coordinates on the basis of the part coordinate system on the grip posture display part F of the input reception screen. The work and the hand 12 may be displayed in a hand coordinate system. The hand 12 is displayed in a pencil shape. The hand 12 has a pencil-shaped tip displayed as the tip position (grip point) of the hand 12. The hand 12 is displayed as a posture of the hand 12 with a pencil-shaped tip rod 40 (Pose A) and a rod 42 (Pose B).

  The teaching device 2 prompts the user to input the grip point and the posture with the first input unit D of the input reception screen. The teaching device 2 prompts the user to input a fine adjustment (rotation around the position A after the rotation) to the second input unit E of the input reception screen. The term “after rotation” refers to a posture in which the gripping point and posture of the hand 12 are determined to some extent with respect to the workpiece. That is, it is urged to designate the rotation with the axis of the Pose A (bar 40) for the current posture. The teaching device 2 teaches the robot 6 the gripping posture information on the installation area of each unit based on this layout design.

  In the input acceptance screen of FIG. 4, the bar 40 indicates the front (front end) direction of the hand 12 and is referred to as “Pose A”, and the direction of the bar 42 indicates the direction in which the finger of the hand 12 opens and is referred to as “Pose B”. Also, when the values are entered with the sliders of the first input part D and the second input part E, or a numerical value is entered in the edit box and confirmed with the Enter key, it is reflected in the gripping point and posture of the hand 12 in the figure. Further, since the fine adjustment rotates around the current hand's Pose A, the rotation around the Poses A may be returned to 0 when the rotation around the xyz axis is changed.

  Here, a specific numerical value is set on the input reception screen. As shown in FIG. 4, the gripping point of the first input unit D is (x, y, z) = (− 49, 15, 21). When it is desired to hold the workpiece from an oblique angle, the rotation α around the x axis is α = 37 degrees, the rotation around the y axis is β = 10 degrees, and the rotation around the z axis is γ = −34 degrees. , The forward direction (Pose A) of the hand 12 before rotating the posture is (x, y, z) = (1, 0, 0), so that (x ′, y ′, z ′) = (0.82, −0.36, −0.45) (note that this is rounded off to the third decimal place). Since the opening / closing direction (Pose B) of the finger of the hand 12 before the posture is rotated is (x, y, z) = (0, 0, 1), (x ′, y ′, z ′) = (0.17, −0.59, 0.79) (not shown).

  After this rotation, if you want to change only the finger opening / closing direction (Pose B) while keeping the forward direction (Pose A) of the hand 12, it is difficult to adjust the posture by changing the numerical values of the rotation α, β, γ around the axis. In this state, the rotation is designated with the front direction (Pose A) of the hand 12 as an axis.

  For example, when the fine adjustment of the second input unit E is a rotation θ around −A = −28 degrees, Pose A of the rotation axis is (a, b, c) = (0.82, −0.36, −0) .45), so when substituting into the expression (2), Pose B of the region G is (x ″, y ″, z ″) = (0.41, −0.19, 0.89) Rounded 3rd).

  5 and 7 are flowcharts for explaining processing according to the present embodiment. FIG. 6 is a specific example of the situation used for explaining the flowchart. As a specific example, as shown in FIG. 6, an example of a single-arm robot that moves a workpiece at the place P1 to the place P2 with the surface C facing down is used. The processing of the flowchart in FIG. It is not limited to.

  When this process is started, first, in step S10, the processing unit 18 receives an input from the user. Specifically, for example, an input such as “Place the work in the place P1 on the place P2 with the surface C facing down” can be considered.

  In step S12, the processing unit 18 starts a scenario creation process in response to the input, and in step S14, the processing unit 18 determines whether the scenario can be created. For example, a scenario is conceivable in which (1) the state of the workpiece is confirmed (2) the workpiece is gripped by the hand (3) the surface C of the workpiece is placed on the place P2 with the surface C facing down. If a scenario cannot be created in step S14, the processing unit 18 displays an error on the display unit 20 and ends the process in step S30.

  If a scenario can be created in step S14, in step S16, the processing unit 18 decomposes the scenario into unit motions and analyzes it. In step S18, the processing unit 18 determines whether the robot 6 can operate. I do.

  Specifically, regarding the step of gripping the workpiece with the hand 12 in the above (2), it can be gripped considering whether the place P1 is within the movable range of the arm or the shape and size of the hand 12 and the workpiece. It is determined whether or not there is.

  If the robot 6 is operable in step S18, in step S20, the processing unit 18 determines whether the analysis of all unit motions has been completed. The analysis is performed, and if completed, the process proceeds to step S22. If it is determined in step S18 that the operation is impossible, the process returns to step S12 to recreate the scenario.

  Next, in step S22, the processing unit 18 analyzes all operations, and in step S24, the processing unit 18 confirms whether there is any inconvenience in the flow of operations. If the operation is possible, the process proceeds to step S26. If the operation is not possible, the process returns to step S12 to recreate the scenario.

  In step S <b> 26, the processing unit 18 selects a grip pattern to be presented when a plurality of grip pattern candidates remain.

  In step S28, the processing unit 18 creates and sends a command to the robot 6.

  A coping example in the case where the operation is not possible as a result of the unit operation analysis in step S18 will be described. For example, if the location P1 or P2 is far and the arm 10 cannot reach, the scenario is changed to a scenario using the other hand in the case of a double-arm robot. In addition, if it is impossible to reach both the places P1 and P2 with only the right hand or the left hand, the scenario is changed to a scenario in which the hand is changed halfway. If the workpiece is large and cannot be gripped with one hand, the scenario may be changed to a scenario in which it is lifted with both palms.

  Next, (2) input of a technique for gripping a workpiece with the hand 12 in the input in step S10 will be described. First, as shown in FIG. 7, in step S50, the processing unit 18 uses the first input unit D on the input reception screen to determine the workpiece gripping point and posture by the robot in the part coordinate system (first coordinate system) from the user. Accepts input.

  Next, in step S52, the processing unit 18 receives the hand 12 and the workpiece on the display unit 20 based on the input of the gripping point and posture of the workpiece by the robot in the part coordinate system from the user. And an input for confirming whether there is any inconvenience in the gripping point and posture of the workpiece by the robot in the part coordinate system is received from the user. If there is no inconvenience, the first gripping posture of the workpiece by the robot in the part coordinate system is determined, and the process proceeds to step S54. If there is inconvenience, the process returns to step S50, and the input of the gripping point and posture of the workpiece by the robot in the part coordinate system is received from the user.

  Next, in step S54, the processing unit 18 receives an input from the user for fine adjustment of the posture of the workpiece by the robot in the hand coordinate system (second coordinate system) at the second input unit E on the input reception screen.

  Specifically, an input of a posture with respect to the current coordinate axis of the hand 12 is received. That is, the image of the first gripping posture is visually displayed on the gripping posture display unit F of the input receiving screen, and the input of the second gripping posture of the workpiece by the robot in the hand coordinate system is received.

  Next, in step S56, the processing unit 18 displays the hand 12 and the workpiece on the display unit 20 on the gripping posture display unit F of the input reception screen based on the fine adjustment input from the user, and the posture from the user. An input for confirming whether there is any inconvenience in the fine adjustment of is accepted. If there is any inconvenience, the process returns to step S54 and accepts the input of fine adjustment of the posture from the user. If there is no inconvenience, the second holding posture is determined, and the subroutine of step S10 is ended.

  After the first gripping posture of the workpiece in the part coordinate system is determined by the steps S50 to S56, the input of the second gripping posture of the workpiece in the hand coordinate system is accepted. Also, using the first holding posture and the second holding posture, the holding posture information to be taught to the robot is determined, and in step S28, the processing unit 18 transmits the holding posture information to the robot 6.

  According to the present embodiment, when teaching the gripping point and posture of the hand 12 that grips the workpiece while looking at the figure displaying the workpiece and the hand 12, the first gripping posture determined in the parts coordinate system and the hand The second gripping posture determined in the coordinate system is overlaid and visually displayed to determine the final gripping posture information, so it is easy to intuitively adjust the posture and teach the gripping posture information more accurately can do. In addition, since the second gripping posture in the hand coordinate system is determined after the first gripping posture in the part coordinate system is determined, it is easy to intuitively adjust the gripping posture information.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Further, the configuration and operation of the robot control device and the robot system are not limited to those described in this embodiment, and various modifications can be made.

  2 ... Teaching device 4 ... Imaging device 6 ... Robot 10 ... Arm 12 ... Hand 14 ... Pallet 16 ... Storage unit 18 ... Processing unit 20 ... Display unit 22 ... External I / F unit 24 ... Work DB 26 ... Robot DB 28 ... Arm DB 30 ... hand DB 32 ... work position calculation unit 34 ... image processing unit 36 ... grip pattern information acquisition unit 38 ... control unit 40, 42 ... bar.

Claims (5)

A robot that grips the workpiece;
A teaching device for teaching the robot the gripping posture information of the workpiece,
The teaching device includes:
Teaching the robot the gripping posture information by receiving a first gripping posture of the workpiece by the robot in a first coordinate system and a second gripping posture of the workpiece by the robot in a second coordinate system;
A robot system characterized by this. The robot system according to claim 1,
The teaching device includes a display unit that displays an input reception screen for receiving the first holding posture and the second holding posture,
The input acceptance screen is
A first input unit for inputting the first holding posture;
A second input unit for inputting the second gripping posture;
A gripping posture display unit that displays the gripping posture of the workpiece by the robot based on the input first gripping posture and the second gripping posture.
A robot system characterized by this. The robot system according to claim 1 or 2,
The first coordinate system is a part coordinate system based on an origin provided on the workpiece.
A robot system characterized by this. The robot system according to any one of claims 1 to 3,
The second coordinate system is a hand coordinate system based on an origin provided in the robot hand.
A robot system characterized by this. The robot system according to any one of claims 1 to 4, wherein
The teaching device includes:
Accepting the second gripping posture after receiving the first gripping posture;
A robot system characterized by this.

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