JP2019118959A - Robot system and robot control method - Google Patents

Abstract

To provide a robot system which can accurately recognize a position of a work-piece even for work-pieces of various shapes.SOLUTION: A robot system performs first processing, second processing, and third processing. In first processing, a robot hand 13 is moved and a first sensor reference point P1 is so made as to be coincident with a first contour 100a. In second processing, the robot hand 13 is rotated around the first sensor reference point P1, and a second sensor reference point P2 is so made as to be coincident with the first contour 100a of the work-piece 100. In third processing, the robot hand 13 is moved in parallel, a distance from the first sensor reference point P1 to the first contour 100a, a distance from the second sensor reference point P2 to the first contour 100a, and a distance from a third sensor reference point P3 to a second contour 100b are so made as to be coincident with previously set target values respectively, and the robot hand 13 or the work-piece 100 is so made as to be coincident with a reference position.SELECTED DRAWING: Figure 2

Description

  The present invention relates mainly to a robot system that recognizes the position of a placed work or a work held by a robot.

  The robot system of Patent Document 1 includes an end effector that holds a work, a position detection sensor that is attached to the end effector, and that detects the position of the work, and a controller. The controller detects a predetermined point of the work (for example, a position of 1⁄4 from each of the four corners to each side) based on the detection result of the position detection sensor. Next, the controller calculates the amount of displacement of the workpiece by comparing the measured position of the specific point with the position of the predetermined point on the predetermined operation. The controller corrects the position of the robot arm based on the amount of deviation.

WO 2009/025271

  In Patent Document 1, rectangular and cylindrical workpieces are described. Such a simple-shaped workpiece can easily recognize the actual position of the workpiece based on the detection result of the position detection sensor. However, for example, when the corner of the workpiece is not a right angle but is arc-shaped or the contour of the workpiece is a curve, it may be difficult to recognize the position of the workpiece based on the detection result of the workpiece. . For example, when the corner is arc-shaped, the specific position of the corner can not be specified, and it becomes difficult to accurately recognize the position of 1⁄4 of each side from the four corners.

  The present invention has been made in view of the above circumstances, and its main object is to provide a robot system capable of accurately recognizing the position of a workpiece even for workpieces of various shapes. is there.

  The problem to be solved by the present invention is as described above, and next, means for solving the problem and its effect will be described.

  According to a first aspect of the present invention, a robot system having the following configuration is provided. That is, this robot system includes a robot, a sensor group, and a correction processing unit. The robot has a robot hand that holds a workpiece. The sensor group detects an outline of the work. The correction processing unit corrects the robot hand or the work to a predetermined reference position by fixing the position of one of the sensor group and the work and moving the other integrally with the robot hand. I do. The sensor group includes a first sensor, a second sensor, and a third sensor. The first sensor measures a distance from a first contour which is a substantially linear contour of the work to a first sensor reference point. The second sensor measures the distance from the first contour of the workpiece to a second sensor reference point. The third sensor measures a distance from a second contour different from the first contour to a third sensor reference point. In a state in which the robot hand or the work is aligned with the reference position, a straight line connecting the first sensor reference point and the second sensor reference point is parallel to the first contour. The correction processing unit performs a first process, a second process, and a third process. The first process moves the robot hand to make the first sensor reference point coincide with the first contour. In the second processing, the robot hand is rotated about the first sensor reference point as a rotation center to make the second sensor reference point coincide with the first contour of the workpiece. In the third processing, the robot hand is moved in parallel, and a distance from the first sensor reference point to the first contour, a distance from the second sensor reference point to the first contour, and the third sensor Each of the distances from the reference point to the second contour is adjusted to a previously set target value, and the robot hand or the work is adjusted to the reference position.

  According to a second aspect of the present invention, the following robot control method is provided. That is, the robot control method includes a first process, a second process, and a third process. In the first processing, the robot hand is moved while the distance from a first contour, which is a substantially linear contour of the workpiece, to a first sensor reference point is measured, and the first sensor reference is determined. Match a point to the first contour. In the second processing, while the distance from the first contour of the workpiece to the second sensor reference point is measured by the second sensor, the robot hand is rotated about the first sensor reference point as the rotation center. A second sensor reference point is made to coincide with the first contour of the workpiece. In the third process, while the distance from the second contour different from the first contour to the third sensor reference point is measured by the third sensor, the robot hand is moved in parallel to move from the first sensor reference point Each of the distance to the first contour, the distance from the second sensor reference point to the first contour, and the distance from the third sensor reference point to the second contour is adjusted to a preset target value. , Aligning the robot hand or the work with a preset reference position. In the first process, the second process, and the third process, one of the sensor group including the first sensor, the second sensor, and the third sensor is fixed, or the other is fixed. Move integrally with the robot hand. In a state in which the robot hand or the work is aligned with the reference position, a straight line connecting the first sensor reference point and the second sensor reference point is parallel to the first contour.

  As a result, since the straight line connecting the first and second sensor reference points is parallel to the contour of the work, the robot hand performs the second process to match the first and second sensor reference points with the contour of the work. Alternatively, since the direction of the workpiece can be adjusted to the same direction as the reference position, the workpiece or the robot hand can be adjusted to the reference position only by performing parallel movement thereafter. Moreover, in this method, if it has a linear contour (first contour) in part, workpieces of various shapes (for example, workpieces with curved corners, workpieces with a partial contour) , The robot hand or the work can be adjusted to the reference position. Further, since attention is paid to the distance to the contour of the workpiece, the correction process can be performed even on a large workpiece which is difficult to measure the entire workpiece.

  According to the present invention, it is possible to realize a robot system capable of accurately recognizing the position of a workpiece even for workpieces of various shapes.

1 is a block diagram showing a configuration of a robot system according to a first embodiment of the present invention. (A) An external appearance perspective view of a robot holding a placed work, and (b) an external appearance perspective view showing a situation where a workpiece before holding is measured using a sensor group provided on a robot hand. The flowchart which shows the pre-processing performed before working with respect to a workpiece | work. The figure explaining the value registered by pre-processing. The flowchart which shows the process which hold | maintains a workpiece | work and correct | amends, correct | amending the position of a robot hand. The figure which shows that there exists an error between the reference position of a workpiece | work, and the actual position of a workpiece | work. FIG. 8 is a view showing the movement of the robot hand in the first process and the second process. The figure which shows the motion of the robot hand in 3rd process. The figure which shows that correction processing can be performed similarly with respect to another workpiece | work with the same robot hand. (A) External perspective view of robot according to the second embodiment, and (b) External perspective view showing how a workpiece held by a robot hand is measured using a fixed sensor group. 6 is a flowchart showing the flow of correction processing and work in the second embodiment. The perspective view which shows the modification provided with the distance sensor which measures the height of a workpiece | work. The perspective view which shows another modification provided with three distance sensors which measure the height of a workpiece | work.

  Next, embodiments of the present invention will be described with reference to the drawings. First, the overall configuration of the robot system 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of a robot system 1 according to an embodiment of the present invention.

  The robot system 1 includes a robot 10, a control device 20, a teaching device 30, and a sensor group 40. The teaching device 30 creates teaching data of the robot 10, and the control device 20 controls the robot 10 using the teaching data, whereby the robot 10 performs a predetermined work on the workpiece 100 which is a work object. Further, the sensor group 40 measures the position of the contour of the workpiece 100 in order to recognize the correct position of the workpiece 100.

  The control device 20 is configured by a known computer, and includes an arithmetic device (CPU or the like) and a storage unit 21 (for example, ROM, RAM, HDD or the like). The storage unit 21 stores programs such as teaching data for causing the robot 10 to operate as taught. The control device 20 controls the robot 10 by the arithmetic device reading and executing this program in the RAM or the like. Thereby, the control device 20 can function as the operation control unit 22 or the correction processing unit 23. The operation control unit 22 operates the robot 10. The correction processing unit 23 performs correction processing for correcting the attitude of the robot 10 based on the detection result of the sensor group 40 (details will be described later).

  The teaching device 30 has a configuration in which software for teaching the robot 10 is installed in a known computer. Accordingly, the teaching device 30 also includes an arithmetic device and a storage unit as the control device 20 does. The teaching device 30 includes a drawing data reading unit 31 and a teaching data processing unit 32, which are realized by the calculation unit.

  The drawing data reading unit 31 reads the drawing data of the workpiece 100. Here, the drawing data read by the teaching device 30 is three-dimensional CAD data created at the time of design or the like. Thereby, the work 100 can be displayed on the virtual space constructed on the computer.

  The teaching data processing unit 32 creates teaching data for operating the robot 10 and corrects the teaching data. In this embodiment, three-dimensional models of the robot 10, peripheral devices, and the work 100 are arranged in the above virtual space, and teaching data are created, instead of actually moving the robot 10. Specifically, the teaching device 30 creates teaching data by the operator setting the work location, the work order, the work content, the work condition, and the like of the work 100 while referring to the above-described virtual space. The teaching data created by the teaching data processing unit 32 is output to the control device 20 and stored in the storage unit 21.

  Here, in the robot system 1 of the present embodiment, the control device 20 and the teaching device 30 are configured from different hardware, but the hardware configuration is arbitrary as long as the function of the present invention can be exhibited. . For example, the control device 20 and the teaching device 30 may be the same hardware, or may be configured to further include other hardware in addition to the control device 20 and the teaching device 30. In addition, at least a part of the functions of the teaching device 30 of the present embodiment may be provided to the control device 20, or at least a part of the functions of the control device 20 may be provided to the teaching device 30.

  Next, specific configurations of the robot 10 and the sensor group 40 will be described with reference to FIG. FIG. 2A is an external perspective view of the robot 10 that holds the placed work 100. FIG. 2B is an external perspective view showing how the workpiece 100 before holding is measured using the sensor group 40 provided on the robot hand 13.

  The robot 10 includes a support 11, an articulated arm 12, and a robot hand 13. The support 11 is fixed at a predetermined position in the facility. The articulated arm 12 has a plurality of joints, and each joint is provided with an actuator. By controlling these actuators by the controller 20, the posture and speed of the articulated arm 12 are adjusted. The robot hand 13 is attached to the tip of the articulated arm 12. The robot hand 13 includes a base body 13a and a suction unit 13b. The suction unit 13 b is attached to the base body 13 a and holds the work 100 by suction.

  In the present embodiment, the work is performed on the work 100 while the robot 10 holds the work 100. Examples of this operation include inspection of the workpiece 100 (inspection for examining surface defects of the workpiece 100, inspection for examining the thickness of the workpiece 100, etc.), painting, cleaning, and the like. Hereinafter, an operation of inspecting the workpiece 100 will be described as an example. The application of the glass plate is not particularly limited. For example, the robot system 1 can be applied to window glass for vehicles such as automobiles, glass used for organic EL panels and liquid crystal panels, and the like.

  More specifically, the robot 10 uses the robot hand 13 to hold the workpiece 100 from the uninspected workpiece placement unit 110. Then, the robot 10 inspects the workpiece 100 by positioning the held workpiece 100 in the inspection space of the inspection apparatus (not shown). Thereafter, the robot 10 places the inspected workpiece 100 on the inspected workpiece placement unit 120. If the inspection result can be detected in real time, the workpiece 100 not satisfying the predetermined criteria may be placed on the placement unit for a defective product.

  The sensor group 40 is attached to the robot hand 13 (specifically, the base body 13a). The sensor group 40 performs a process of detecting the contour of the workpiece 100 before the robot hand 13 holds the workpiece 100. The detection result of the sensor group 40 is output to the correction processing unit 23 of the control device 20. The sensor group 40 includes a first sensor 41, a second sensor 42, and a third sensor 43.

  The first sensor 41 includes an irradiation unit 41 a and a light receiving unit 41 b. The irradiation unit 41 a irradiates the laser beam toward the workpiece 100 (downward). The laser beam emitted by the irradiation unit 41a is a laser beam whose irradiation area in the horizontal plane (that is, on the workpiece 100) is linear. The irradiation part 41a irradiates a laser beam so that a linear irradiation area | region and the outline of the workpiece | work 100 may cross | intersect. The light receiving unit 41 b receives the reflected light of the laser beam emitted by the irradiating unit 41 a. The reflected light obtained by the laser beam reflected by the work 100 and the reflected light reflected by the mounting surface on which the laser light is placed are different in timing at which the light receiving portion 41b receives the reflected light. Therefore, the contour of the workpiece 100 is present in the portion where the light reception timing difference occurs. The first sensor 41 detects the contour of the workpiece 100 according to the above principle. The second sensor 42 also includes the same irradiation unit 42a and light reception unit 42b, and the third sensor 43 also includes the same irradiation unit 43a and light reception unit 43b. As described above, each of the first sensor 41, the second sensor 42, and the third sensor 43 is a reflection type laser sensor in which the irradiation area is linear.

  Next, pre-processing will be described with reference to FIGS. 3 and 4. The pre-processing is processing that is performed in advance before the correction processing for correcting the position of the robot hand 13. Therefore, pre-processing is processing performed in an ideal positional relationship using drawing data. The position of the robot hand 13 at this time is referred to as a reference position. FIG. 3 is a flowchart showing the pre-processing. FIG. 4 is a diagram for explaining values to be registered in the pre-processing. In the following description, these three sensors may be collectively referred to as sensors 41, 42, 43.

  In the following description, terms such as "straight line" and "parallel" are intended to include not only configurations that are strictly straight and parallel but also configurations that have slight errors.

  First, the shape of the workpiece 100 will be described. The workpiece 100 assumed in the present embodiment includes a linear contour. In the present embodiment, a linear contour (hereinafter, first contour 100 a) of the workpiece 100 is set as a first detection target by the sensor group 40. Moreover, in order to perform the process of the present embodiment, the workpiece 100 may include at least one linear contour. When the workpiece 100 includes a plurality of linear contours, one of them may be treated as the first contour 100a. Further, among the contours of the workpiece 100, a contour different from the first contour 100a is referred to as a second contour 100b, and is used as a second detection target by the sensor group 40. The second contour 100b may be linear or curved, but is preferably not parallel to the first contour 100a.

  In the pre-processing, first, three sensor reference points are registered in a state where the robot hand 13 is at the reference position (S101). A sensor reference point is a point used as a reference at the time of measuring by sensors 41, 42, and 43. The sensor reference point of the first sensor 41 is the first sensor reference point P1, the sensor reference point of the second sensor 42 is the second sensor reference point P2, and the sensor reference point of the third sensor 43 is the third sensor reference point It is P3. Further, it is preferable that the third sensor reference point P3 be apart from the sensor reference points P1 and P2. For example, when the sensor reference points P1 and P2 are on one side of an imaginary line that divides the workpiece 100 into two, it is preferable that the third sensor reference point P3 be disposed on the other side. Hereinafter, the three sensor reference points may be collectively referred to as sensor reference points P1, P2, and P3.

  The sensors 41, 42, 43 output the distance from the sensor reference points P1, P2, P3 to the end (outline) of the workpiece 100 as a measurement result. The sensor reference points P1, P2, and P3 are generally at the center of the linear detection range, but may be offset from the center. In step S101, coordinate values of three sensor reference points P1, P2, and P3 in the robot coordinate system are registered.

  In this embodiment, the X coordinate value (Lx1) in the robot coordinate system of the first sensor reference point P1 and the X coordinate value (Lx2) of the second sensor reference point P2 are set to be the same. . In other words, the straight line connecting the sensor reference points P1 and P2 is parallel to the Y axis. The detection range of the sensors 41 and 42 is parallel to the X axis. Moreover, although the detection range of the sensors 41 and 42 is the same in this embodiment, it may differ. Further, the value (Ly1) of the Y coordinate of the first sensor reference point P1 and the value (Ly2) of the Y coordinate of the second sensor reference point P2 are also registered. On the other hand, the X coordinate value (Lx3) of the third sensor reference point P3 and the Y coordinate value (Ly3) are similarly registered. The detection range of the third sensor 43 is parallel to the Y axis.

  Next, in a state where the robot hand 13 is at the reference position, registration of the distances from the three sensor reference points P1, P2, P3 to the contour of the workpiece 100 is performed (S102). As described above, since the pre-processing is performed in the ideal positional relationship using the drawing data, the distance registered here indicates the ideal distance (that is, the target value at the time of the correction processing). In the present embodiment, the work 100 is disposed such that the first contour 100 a is parallel to the Y axis. Therefore, the straight line connecting the two sensor reference points P1 and P2 is parallel to the first contour 100a. The values to be specifically registered are, for the sensor reference points P1 and P2, the distance to the first contour 100a (difference in the value of the X coordinate, specifically, Δx1 and Δx2). The third sensor reference point P3 is the distance to the second contour 100b (difference in Y coordinate value, specifically Δy3). Therefore, the directions of the detection ranges of the sensors 41 and 42 and the third sensor 43 differ by 90 degrees. In addition, although it is (DELTA) x1 = (DELTA) x2 when 1st outline 100a is a perfect straight line, a difference arises in both otherwise. Further, although details will be described later, at least one of Δx1, Δx2, and Δy3 may be zero.

  Next, the correction process will be described with reference to FIGS. 5 to 9. FIG. 5 is a flowchart showing processing for holding the workpiece 100 and performing work while correcting the position of the robot hand 13. FIG. 6 is a diagram showing that there is an error between the reference position of the workpiece 100 and the actual position of the workpiece 100. 7 to 9 are diagrams showing the flow of the correction process.

  Here, since the pre-processing is theoretically (on data), there is no error in the position of the work 100, etc., but the work 100 actually placed is the object during work (during inspection). Therefore, an error is included in the position of the workpiece 100 (see FIG. 6). Therefore, even when the robot 10 carries out the inspection as taught, the actual position of the workpiece 100 is shifted, so that the inspection position may differ and the inspection may not be performed as expected. Moreover, when operating the robot 10, the possibility that the workpiece 100 may collide with a peripheral device or an inspection device is also considered. In consideration of the above, in the present embodiment, the inspection process is performed while correcting the error of the position of the workpiece 100.

  However, in general, if the workpiece has a rectangular corner, the position of the workpiece 100 can be accurately recognized only by specifying the corner. In addition, even if the corner is chamfered in a curved shape, if the two contours directed to the corner are straight lines, the position of the work can be accurately determined by using the intersection of the two straight lines. It can be recognized. However, if at least one of the contours directed to the corner is a curve, it is difficult to accurately recognize the position of the workpiece 100 only by detecting a part of the workpiece 100 by the conventional method. In this respect, in the present embodiment, the position of the work 100 can be recognized accurately and easily by performing the process using the distance from the contour of the work 100 registered in the pre-processing. The details will be described below. Further, the correction processing described below is performed by the correction processing unit 23.

  First, the operation control unit 22 moves the robot hand 13 to the upper part of the uninspected work placement unit 110 based on the content taught in advance (S201). At this time, the robot hand 13 does not hold the workpiece 100 yet, and performs the following correction processing above the workpiece 100. Further, at this point of time, high accuracy is not required for the position of the robot hand 13 with respect to the workpiece 100. For example, it is sufficient if the sensor group 40 can detect the contour of the workpiece 100.

  Next, the correction processing unit 23 moves the robot hand 13 to make the first sensor reference point P1 coincide with the first contour 100a of the workpiece 100 (S202, first processing). Further, the correction processing unit 23 moves the robot hand 13 and also moves the robot coordinate system by the same amount (the same applies to the subsequent processes). Specifically, the correction processing unit 23 can grasp the distance between the first sensor reference point P1 and the first contour 100a (specifically, the difference between the X coordinate values) based on the detection result of the first sensor 41. , The robot hand 13 is moved so that this distance becomes zero. In the present embodiment, it is assumed that the robot hand 13 is moved in parallel (it is moved without changing the direction), but the robot hand 13 may be rotated if it is slightly.

  Next, the correction processing unit 23 rotates the robot hand 13 about the first sensor reference point P1 as a rotation center to make the second sensor reference point P2 coincide with the first contour 100a of the workpiece 100 (S203, second processing) ). Specifically, as in step S101, the correction processing unit 23 determines the distance between the second sensor reference point P2 and the first contour 100a (specifically, the value of the value of the X coordinate) based on the detection result of the second sensor 42. Since the difference) can be grasped, the robot hand 13 is rotated so that this distance becomes zero.

  By rotating the robot hand 13 in this manner, the straight line connecting the two sensor reference points P1 and P2 becomes parallel to the first contour 100a. Therefore, with regard to the orientation of the robot hand 13 and the work 100, the same situation as in the pre-processing is realized.

  Next, the correction processing unit 23 moves the robot hand 13 in parallel to make the third sensor reference point P3 coincide with the second contour 100b of the workpiece 100 (S204, third pre-processing). Specifically, as in steps S101 and S102, the correction processing unit 23 determines the distance between the third sensor reference point P3 and the second contour 100b based on the detection result of the third sensor 43. Since the difference in value) can be grasped, the robot hand 13 is moved so that this distance becomes zero. Since the direction of the robot hand 13 has already been adjusted to the correct direction, the correction processing unit 23 moves (translates) the robot hand 13 without rotating it.

  Next, the correction processing unit 23 moves the robot hand 13 in parallel to the X axis and the Y axis to set the distances from the three sensor reference points P1, P2, P3 to the contour of the workpiece 100 to the target values (Δx1, Δx2 , Δy 3) (S 205, third correction processing). Here, at the stage where the third pre-processing is completed, all three sensor reference points P1, P2, P3 are positioned on the contour of the workpiece 100. Then, in the pre-processing, the target values (Δx1, Δx2, Δy3) of the distances from the three sensor reference points P1, P2, P3 to the contour of the work 100 are registered. Therefore, by performing the third pre-processing and moving the robot hand 13 next by the above-described target value, the robot hand 13 can be aligned with the reference position determined in the pre-processing. Thus, the correction process is completed.

  Next, the operation control unit 22 lowers the robot hand 13 and holds the workpiece 100, and performs inspection work and the like using the position of the robot hand 13 after this correction processing and the robot coordinate system (S206). When it is determined that the work is completed (S207), the work 100 is moved to the inspected work placement unit 120, and the work 100 is released (S208). Thereafter, the operation control unit 22 performs the process of step S201 and subsequent steps on the next workpiece 100 placed on the uninspected workpiece placement unit 110. By repeating the above processing, it is possible to work while automatically correcting the position of the robot hand 13 according to the positional deviation of the workpiece 100.

  Next, with reference to FIG. 9, it will be described that the robot system 1 can execute the correction process on a plurality of types of workpieces 100. FIG. The robot system 1 is required to perform work on workpieces 100 of various shapes. However, replacing the jig for fixing the configuration of the robot 10 and the position of the workpiece 100 every time the workpiece 100 to be worked is changed is very time-consuming and increases the operation cost. Therefore, the robot system 1 of the present embodiment is configured to be able to perform operations on a plurality of types of workpieces 100 without changing the mechanical configuration as much as possible.

  Specifically, in addition to the work 100 described above, pre-processing (in particular, the process of step S102) is performed on another work 100, and the target value of the work 100 is registered in the storage unit 21. Then, when changing the work 100 to be worked, the robot system 1 notifies the robot system 1 to that effect, and the robot system 1 performs the correction process and the work on the work 100 after the change as described above. Therefore, unless the work 100 is extremely different in size and shape, work can be continued without changing the mechanical configuration.

  Three examples of the work 100 in which the storage unit 21 stores the target value are shown in FIG. 9. Each work 100 has a first outline 100a which is a linear outline, and in the state where the robot hand 13 is at the reference position, this line is parallel to a line connecting the sensor reference points P1 and P2 It is set to. Further, as shown in FIG. 9A to FIG. 9C, the orientation of the robot hand 13 at the reference position may be different for each work 100.

  Further, as shown in FIG. 9A, the sensor reference points P1 and P2 may be made to coincide with the first contour 100a. In this case, two target values of Δx1 and Δx2 become zero. Further, by performing the third pre-processing (S204), the position of the X coordinate of the sensor reference points P1 and P2 is already matched with the reference position. Therefore, in the third correction process (S205), the robot hand 13 can be aligned with the reference position only by moving the robot hand 13 in the direction parallel to the first contour 100a.

  Further, as shown in FIG. 9B, the sensor reference points P1 and P2 may be arranged with respect to the first contour 100a which is not strictly a straight line. In this case, by performing the third pre-processing (S204), the second sensor reference point P2 will deviate from the first contour 100a, but after that, the first processing (S202) and the second processing (S202) are performed again. By performing a series of processes of S203) and the third pre-processing (S204), the amount of deviation can be reduced. If the error is large even if the above series of processing is performed twice, this series of processing may be further performed. Errors can be converged by repeating this series of processing. Then, by performing the third correction processing (S205) after that, the robot hand 13 can be adjusted to the reference position.

  Next, a second embodiment will be described with reference to FIGS. 10 and 11. FIG. 10A is an external perspective view of the robot 10 according to the second embodiment. FIG. 10B is an external perspective view showing how the workpiece 100 held by the robot hand 13 is measured using the fixed sensor group 40. FIG. 11 is a flow chart showing the flow of correction processing and work in the second embodiment.

  In the first embodiment, by performing the correction process before holding the workpiece 100 by the robot hand 13, the robot hand 13 can hold the workpiece 100 as defined in the pre-processing. On the other hand, in the second embodiment, the correction process is performed with the robot hand 13 holding the work 100. Further, in the second embodiment, the sensor group 40 is fixed to a predetermined inspection table or the like, and the sensor group 40 does not move even if the robot hand 13 moves. In other words, in the first embodiment, the robot hand 13 and the sensor group 40 move integrally to correct the position of the robot hand 13 with respect to the workpiece 100 (set the robot hand 13 to the reference position). On the other hand, in the second embodiment, the robot hand 13 and the workpiece 100 move integrally, and the position of the workpiece 100 with respect to the mounting surface, the inspection apparatus, etc. is corrected (the workpiece 100 is adjusted to the reference position). Do.

  Further, since the sensor group 40 is fixed, the sensors 41, 42 and 43 of the second embodiment are transmission type laser sensors. Specifically, the irradiating unit 41a and the light receiving unit 41b are disposed to face each other. The irradiation unit 41 a irradiates the light receiving unit 41 b with laser light whose irradiation region is linear. In the portion where the work 100 is present between the irradiation unit 41a and the light receiving unit 41b, the light receiving unit does not receive the laser light because the laser light is blocked. On the other hand, in the portion where the work 100 is not present between the irradiation unit 41a and the light receiving unit 41b, the light receiving unit receives the laser light because the laser light is not blocked. The sensor 41 detects the position of the work 100 according to the above principle. The same applies to the second sensor 42 and the third sensor 43.

  In the reflection type laser sensor of the first embodiment, when the end (outline) of the workpiece 100 is processed (chamfered) into an R shape (arc shape), an error is detected in the position of the end of the workpiece 100 May occur. On the other hand, the transmission type laser sensor of the second embodiment is not configured to detect reflected light, regardless of the shape of the end of the work 100 (for example, the surface where the reflected light travels in an unexpected direction) Even if it is a shape, the position of the end of the workpiece 100 can be detected accurately.

  In the second embodiment, correction processing is performed while holding the workpiece 100 unlike the first embodiment, but when the robot hand 13 is moved, the positional relationship between the sensor group 40 and the workpiece 100 changes. Is the same. Therefore, the second embodiment can perform almost the same correction processing as the first embodiment.

  In addition, since there are differences in points other than the correction processing, the differences will be described. The processes of steps S301 to S308 correspond to the processes of steps S201 to S208. Although only the positioning of the robot hand 13 on the work 100 of the uninspected work placement unit 110 is described in step S201, holding of the work 100 of the uninspected work placement unit 110 is described in step S301. There is. In addition, although holding of the work 100 is described in step S206, since the work is already held in step S306, this point is not described.

  Next, modifications of the first embodiment and the second embodiment will be described with reference to FIGS. 12 and 13. FIG. 12 is a perspective view showing a modification including the distance sensor 44 for measuring the height of the work 100. As shown in FIG. In this case, the height at the point where the distance sensor 44 is disposed is obtained in advance based on the drawing data of the workpiece 100 at the time of pre-processing. In the modification of the first embodiment, as shown in FIG. 12A, a distance sensor 44 such as a laser sensor is disposed on the robot hand 13. In the modification of the second embodiment, as shown in FIG. 12B, the distance sensor 44 is fixed to a work table or the like (the third sensor 43 in the figure). Then, after the robot hand 13 or the work 100 is aligned with the reference position, the distance sensor 44 performs measurement. Thereafter, the error in the height direction can be calculated by comparing the height obtained in the pre-processing and the height obtained based on the distance sensor 44. Accordingly, the robot hand 13 is moved accordingly to adjust the robot coordinate system The position in the height direction can be corrected by changing. Further, as shown in FIG. 13, when the distance sensors 44 are arranged at at least three locations, the height of the workpiece 100 can be measured in three dimensions, so three-dimensional height correction can be performed.

  As described above, the robot system 1 according to the embodiment includes the robot 10, the sensor group 40, and the correction processing unit 23. Also, robot control is performed by the robot system 1. The robot 10 has a robot hand 13 that holds the work 100. The sensor group 40 detects the contour of the workpiece 100. The correction processing unit 23 fixes the position of one of the sensor group 40 and the work 100 and moves the other integrally with the robot hand 13 to make the robot hand 13 or the work 100 match the reference position set in advance. I do. The sensor group 40 includes a first sensor 41, a second sensor 42, and a third sensor 43. The first sensor 41 measures the distance from the first contour 100a, which is a substantially linear contour of the workpiece 100, to the first sensor reference point P1. The second sensor 42 measures the distance from the first contour 100 a of the workpiece 100 to the second sensor reference point P2. The third sensor 43 measures the distance from the second contour 100b different from the first contour 100a to the third sensor reference point P3. In a state in which the robot hand 13 or the workpiece 100 is aligned with the reference position, a straight line connecting the first sensor reference point P1 and the second sensor reference point P2 is parallel to the first contour 100a. The correction processing unit 23 performs a first process, a second process, and a third process. The first process moves the robot hand 13 to make the first sensor reference point P1 coincide with the first contour 100a. In the second process, the robot hand 13 is rotated about the first sensor reference point P1 to make the second sensor reference point P2 coincide with the first contour 100a of the workpiece 100. In the third process, the robot hand 13 is moved in parallel, and the distance from the first sensor reference point P1 to the first contour 100a, the distance from the second sensor reference point P2 to the first contour 100a, and the third sensor reference point Each of the distances from P3 to the second contour 100b is adjusted to a previously set target value, and the robot hand 13 or the workpiece 100 is adjusted to the reference position.

  Thereby, since the straight line connecting the sensor reference points P1 and P2 and the contour of the work 100 are parallel, the robot hand 13 or the robot hand 13 or the second processing is performed to make the sensor reference points P1 and P2 coincide with the first contour 100a. Since the direction of the work 100 can be adjusted to the same direction as the reference position, the work 100 or the robot hand 13 can be adjusted to the reference position only by performing parallel movement thereafter. In addition, in this method, if the linear contour (first contour 100a) is partially included, workpieces 100 of various shapes (for example, the workpiece 100 whose corner is curved, a portion of the contour is curved) The robot hand 13 or the workpiece 100 can be adjusted to the reference position. In addition, since attention is paid to the distance to the contour of the workpiece 100, the correction process can be performed even on a large workpiece 100 in which it is difficult to measure the entire workpiece 100.

  Moreover, in the robot system 1 of the said embodiment, the memory | storage part 21 which memorize | stores a target value for every several workpiece | work 100 from which a shape differs is provided.

  Thus, the correction process can be performed on the workpiece 100 having a different shape only by changing the target value to be read.

  Further, in the robot system 1 of the above-described embodiment, the third process includes a third pre-process and a third correction process. In the third pre-processing, the robot hand 13 is moved in parallel with the first contour 100a to make the third sensor reference point P3 coincide with the second contour 100b. In the third correction processing, after the third pre-processing, the robot hand 13 is translated in at least one of a direction parallel to the first contour 100a and a direction perpendicular to the first contour 100a to align the robot hand 13 or the workpiece 100 with the reference position.

  Thus, the third correction process is performed by performing the process of adjusting to the reference position based on the distance from the sensor reference points P1, P2, and P3 to the first contour 100a or the second contour 100b in the third correction process. The third correction process can be performed in a short time and with a simple calculation.

  Further, in the robot system 1 of the above-described embodiment, the correction processing unit 23 completes the correction processing by performing the first processing, the second processing, and the third processing once each.

  Thereby, for example, when the straight line connecting the sensor reference points P1 and P2 and the first contour 100a are exactly parallel or high positional accuracy is not required, the correction process can be performed in a short time by doing as described above. It can be completed.

  In the robot system 1 according to the above-described embodiment, the correction processing unit 23 performs the third correction process after performing the series of processes of the first process, the second process, and the third preliminary process a plurality of times. Correction processing can be completed.

  Thereby, even if, for example, the straight line connecting the sensor reference points P1 and P2 and the first contour 100a are not sufficiently parallel, the workpiece 100 or the robot hand 13 can be made accurate by performing the above-described series of processing a plurality of times. It can be well adjusted to the reference position.

  Further, in the robot system 1 of the above-described embodiment, the sensor group 40 is attached to the robot hand 13. In the correction process, the robot hand 13 is adjusted to the reference position.

  Thereby, even when the position of the work 100 placed on the mounting table (for example, the uninspected work placement unit 110) is shifted, the robot hand 13 holds the predetermined position of the work 100. Can.

  Further, in the robot system 1 of the above-described embodiment, the correction process is performed in a state where the robot hand 13 holds the work 100, and in the correction process, the work 100 is aligned with the reference position.

  Thus, even when the holding position of the work 100 by the robot hand 13 is shifted, the work 100 can be moved as predetermined by moving the robot hand 13.

  Although the preferred embodiment and modification of the present invention have been described above, the above configuration can be modified as follows, for example.

  The flowcharts shown in FIG. 3 and FIG. 11 are an example, and addition, deletion, and order change of processing may be performed as long as the effects of the present invention can be exhibited. Further, two or more processes may be simultaneously performed.

  In the above embodiment, the teaching device 30 reads the drawing data of the workpiece 100. However, the drawing data of the workpiece 100 may be created on the application executed by the teaching device 30.

  In the above embodiment, although the configuration is such that the position of the contour up to the workpiece 100 is measured using a laser sensor whose irradiation area is linear, a sensor having another configuration can also be used.

  In the above embodiment, the robot hand 13 or the workpiece 100 is moved to the reference position after the third preliminary processing is performed to align the three sensor reference points P1, P2, P3 with the contour of the workpiece 100. However, this third pre-processing may be omitted, and processing for moving the robot hand 13 or the work 100 to the reference position may be performed after the second processing.

DESCRIPTION OF SYMBOLS 1 robot system 10 robot 11 support stand 12 articulated arm 13 robot hand 20 control device 21 storage unit 22 motion control unit 23 correction processing unit 30 teaching device 40 sensor group P1 first sensor reference point P2 second sensor reference point P3 third Sensor reference point

Claims (10)

A robot having a robot hand that holds a work;
A sensor group that detects the contour of the work;
A correction processing unit that performs correction processing to fix the robot hand or the work to a predetermined reference position by fixing one position of the sensor group and the work and moving the other integrally with the robot hand ,
Equipped with
The sensor group is
A first sensor for measuring a distance from a first contour which is a substantially linear contour of the work to a first sensor reference point;
A second sensor that measures a distance from the first contour of the workpiece to a second sensor reference point;
A third sensor that measures a distance from a second contour different from the first contour to a third sensor reference point;
Equipped with
A straight line connecting the first sensor reference point and the second sensor reference point is parallel to the first contour in a state in which the robot hand or the work is aligned with the reference position.
The correction processing unit
A first process of moving the robot hand to make the first sensor reference point coincide with the first contour;
A second process of rotating the robot hand about the first sensor reference point as a rotation center to make the second sensor reference point coincide with the first contour of the workpiece;
The robot hand is moved in parallel, and the distance from the first sensor reference point to the first contour, the distance from the second sensor reference point to the first contour, and the third sensor reference point to the second A third process of setting the robot hand or the work to a reference position in accordance with a predetermined target value for each of the distances to the contour;
A robot system characterized by performing. The robot system according to claim 1,
A robot system comprising: a storage unit for storing the target value for each of a plurality of workpieces having different shapes. The robot system according to claim 1 or 2, wherein
The third process is
Third pre-processing of moving the robot hand parallel to the first contour to make the third sensor reference point coincide with the second contour;
After the third pre-processing, a third correction process of translating the robot hand in at least one of a direction parallel to the first contour and a direction perpendicular to the first contour to align the robot hand or the workpiece with a reference position;
A robot system characterized by including. The robot system according to any one of claims 1 to 3, wherein
A robot system characterized in that the correction process is completed by performing the first process, the second process, and the third process once each. The robot system according to claim 3,
After the correction process performs a series of processes of the first process, the second process, and the third pre-process over a plurality of times, the correction process is completed by performing the third correction process. Robot system to feature. The robot system according to any one of claims 1 to 5, wherein
A robot system, wherein the sensor group is attached to the robot hand, and in the correction process, the robot hand is adjusted to a reference position. The robot system according to claim 6, wherein
A robot system characterized in that each of the first sensor, the second sensor, and the third sensor is a reflection type laser sensor whose irradiation area is linear. The robot system according to any one of claims 1 to 5, wherein
The robot system is characterized in that the correction process is performed in a state where the robot hand holds the work, and in the correction process, the work is adjusted to a reference position. The robot system according to claim 8, wherein
A robot system characterized in that each of the first sensor, the second sensor, and the third sensor is a transmission type laser sensor whose irradiation area is linear. In a robot control method for controlling a robot having a robot hand holding a work,
The robot hand is moved while the distance from the first contour, which is a substantially linear contour of the workpiece, to the first sensor reference point is measured by the first sensor, and the first sensor reference point is moved to the first contour A first process to match
The robot hand is rotated about the first sensor reference point as the second sensor reference point while the distance from the first contour of the workpiece to the second sensor reference point is measured by the second sensor. A second process for matching the first contour of the workpiece;
The robot hand is moved in parallel while the distance from the second contour to the third sensor reference point different from the first contour is measured by the third sensor, and the distance from the first sensor reference point to the first contour is The robot hand or the above according to the target values set in advance, each of the distance, the distance from the second sensor reference point to the first contour, and the distance from the third sensor reference point to the second contour, A third process of aligning the workpiece to a preset reference position;
Including
In the first process, the second process, and the third process, one of the sensor group including the first sensor, the second sensor, and the third sensor is fixed, or the other is fixed. Move integrally with the robot hand
Robot control characterized in that a straight line connecting the first sensor reference point and the second sensor reference point is parallel to the first contour in a state in which the robot hand or the work is aligned with the reference position. Method.

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