JP2010264560A - Robot interference prevention method - Google Patents

Abstract

A method for detecting the presence or absence of an object approaching a robot by a simple method is provided.
An imaging process in step S1 for generating an image by imaging a second robot using a third imaging device installed on a third arm of the first robot and having a fixed focus; a turntable of the first robot; A moving step in step S2 for moving the first arm, the second arm, and the third arm, and an image determining step in step S3 for detecting whether a focused image, which is an image focused on the generated image, is captured; An interference prevention step of step S4 that does not narrow the distance between the hand portion and the second robot when the focused image is captured.
[Selection] Figure 4

Description

  The present invention relates to a robot interference prevention method, and more particularly to a method for detecting an obstacle.

  Robots are used for various tasks such as moving a workpiece. There are cases where an environment in which a workpiece and an object move or a plurality of robots collaborate. At this time, the robot needs to operate so as not to interfere with various objects.

  A method for preventing the robot from interfering is disclosed in Patent Document 1. According to this, a target object approaching the robot is photographed a plurality of times with a camera (hereinafter referred to as an imaging device). Next, the captured image is subjected to image processing to detect the moving direction and speed of the target object. Then, the time and place where the robot and the target object interfere with each other are calculated and predicted. And the treatment which prevents interference was implemented.

JP 2007-320024 A

  When taking images of a moving object continuously and calculating interference between the object and the robot from a plurality of images, a complicated processing process and an arithmetic device capable of high-speed calculation are required. Therefore, a method for detecting the presence or absence of an object approaching the robot by a simple method has been desired.

  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 method for preventing interference of a robot according to this application example, in which an imaging process is performed by capturing an object using an imaging device installed on a movable part of the robot and having a fixed focal point, and movement for moving the movable part An image determining step for detecting whether a focused image, which is an image focused on the image, and an interval between the movable portion and the subject are not narrowed when the focused image is captured. An interference prevention step.

  According to this robot interference prevention method, the focus of the imaging device is fixed. Therefore, the range in which a focused image can be captured is limited. When an image focused on the photographed image can be detected, it is determined that the subject is present at a predetermined distance from the imaging device.

  When it is determined that the subject is located at a predetermined distance from the movable part, the distance between the movable part and the subject is not reduced. Therefore, it is possible to prevent the movable part and the subject from interfering with each other.

[Application Example 2]
In the robot interference prevention method according to the application example described above, a position where the outermost periphery of the movable range of the movable portion moves is set as a movable tip portion, and the imaging apparatus is focused at a position away from the movable tip portion by a predetermined distance. As described above, the image pickup apparatus is adjusted.

  According to this robot interference prevention method, it is possible to detect whether or not a subject is present at a predetermined distance from the movable tip. When the subject approaches the movable range, it passes through the outermost periphery of the subject range and enters the movable range. In addition, the possibility that the location of the movable tip portion approaches the subject is higher than the possibility that the location other than the movable tip portion approaches the subject. Therefore, it is possible to increase the possibility of detecting a subject approaching the movable part, as compared with the case where the imaging apparatus photographs near a place other than the movable tip.

[Application Example 3]
In the robot interference prevention method according to the application example, the robot includes a plurality of the movable parts, and the robot includes a plurality of the movable tip parts and the imaging device.

  According to this robot interference prevention method, the robot includes a plurality of movable parts and an imaging device. Therefore, the robot can change its posture. At this time, the movable tip portion is switched depending on how the movable portion is moved. Also at this time, it is possible to increase the possibility that the imaging device detects a subject approaching the movable tip.

[Application Example 4]
In the robot interference prevention method according to the application example described above, a distance between the movable tip portion and a place where the imaging apparatus is focused is set as a detection distance, and after the determination to stop the movable tip portion is performed, the movable tip portion is When the distance that the movable tip moves during the stop is defined as a stop distance, the detection distance is more than the stop distance.

  According to this robot interference prevention method, it is possible to detect whether or not a subject is present at a position that is more than the stop distance from the movable tip. When there is a subject, the distance between the subject and the movable tip is greater than the stop distance. Accordingly, it is possible to prevent the movable portion and the subject from interfering when the movable portion is stopped.

The schematic perspective view which shows the structure of a picking apparatus. The schematic perspective view which shows a robot. The electric control block diagram of a picking apparatus. The flowchart which shows the movement operation | movement of a hand part. The schematic diagram for demonstrating the robot control method in the movement operation | movement of a hand part. The schematic diagram for demonstrating the robot control method in the movement operation | movement of a hand part. The schematic diagram for demonstrating the robot control method in the movement operation | movement of a hand part. The schematic diagram for demonstrating the robot control method in the movement operation | movement of a hand part.

Hereinafter, embodiments will be described with reference to the drawings. In addition, each member in each drawing is illustrated with a different scale for each member in order to make the size recognizable on each drawing.
(First embodiment)
A picking device using a robot in this embodiment and a characteristic robot control method for preventing robot interference will be described with reference to FIGS. The picking device is a device that moves a workpiece by gripping, moving, and releasing the workpiece.

(Picking device)
FIG. 1 is a schematic perspective view showing the configuration of the picking apparatus. As shown in FIG. 1, the picking device 1 mainly includes a supply device 2, a first robot 3, a second robot 4 as a subject, a transport device 5, and a control device 6. The picking device 1 has a function of moving the workpiece 7 from the supply device 2 to the transport device 5.

  The supply device 2 is a device that supplies the workpiece 7. The shape and material of the workpiece 7 are not particularly limited. It is sufficient that the first robot 3 and the second robot 4 can be gripped. The supply device 2 includes a base 8 that is long in one direction. The longitudinal direction of the base 8 is defined as the X direction. Then, on the horizontal plane, the direction orthogonal to the X direction is defined as the Y direction. The vertical direction is the Z direction. A pair of side plates 9 are arranged on both sides of the base 8 in the Y direction.

  A belt 10 is disposed between the two side plates 9. The belt 10 is made of a sheet formed in a cylindrical shape, and a pair of pulleys (not shown) are arranged inside the belt 10. A predetermined tension is applied to the belt 10 in the X direction by the pulley. Of the two side plates 9, a motor 11 is arranged on the left side of the lower right side plate 9 in the figure, and the drive shaft of the motor 11 is connected to a pulley. A workpiece 7 is placed on the upper surface of the belt 10. The workpiece 7 is placed on the belt 10 by a supply device (not shown). Then, by driving and stopping the motor 11, the workpiece 7 can be moved in the X direction via the belt 10 and stopped at a predetermined place.

  A first robot 3 is arranged on the right side of the supply device 2 in the drawing. In the present embodiment, vertical articulated robots are employed for the first robot 3 and the second robot 4, but the present invention is not limited to this, and various robots such as horizontal articulated robots and orthogonal robots can be employed. The first robot 3 includes a movable portion and a hand portion 12 as a movable tip portion, and the hand portion 12 can grip the workpiece 7. The first robot 3 can move the workpiece 7 by changing the posture while holding the workpiece 7.

  A second robot 4 is arranged on the upper right of the first robot 3 via an intermediate platform 13. The intermediate table 13 is a table used when the workpiece 7 is transferred from the first robot 3 to the second robot 4. The first robot 3 carries the workpiece 7 from the supply device 2 and places it on the intermediate table 13. Next, the second robot 4 grips and moves the workpiece 7 on the intermediate table 13.

  The second robot 4 is the same device as the first robot 3. The second robot 4 includes a hand portion 12 as a movable portion, and the hand portion 12 can grip the workpiece 7. The second robot 4 can move the workpiece 7 by changing the posture while holding the workpiece 7.

  A transfer device 5 is arranged on the upper right side of the second robot 4 in the drawing. The transport device 5 includes a mechanism similar to that of the supply device 2. And the belt 10 which moves to a X direction is provided, and the workpiece | work 7 mounted on the belt 10 is moved to a X direction.

  A control device 6 is arranged at the upper left of the supply device 2 in the figure. The control device 6 is a device that controls the operation of each device constituting the picking device 1.

  FIG. 2 is a schematic perspective view showing the robot. As shown in FIG. 2, the first robot 3 includes a base 16, and a turntable 17 as a movable part is disposed on the base 16. The turntable 17 includes a fixed stand 17a and a rotation shaft 17b. The turntable 17 includes a servo motor and a speed reduction mechanism inside, and can rotate and stop the rotation shaft 17b with high angular accuracy.

  A first joint 18 as a movable part is arranged connected to the rotation shaft 17b of the turntable 17, and a first arm 19 as a movable part is arranged connected to the first joint 18.

  In the first arm 19, a first imaging device 21 is disposed on one surface on the right side in the drawing via a rotating pedestal 20. The rotation base 20 has a rotation mechanism inside and can rotate the first imaging device 21. Then, when the control device 6 rotates the rotary base 20, the direction in which the first imaging device 21 captures an image can be changed. The photographic lens 21a includes a focus adjustment mechanism that adjusts the focus according to the instruction signal. The operator performs focus adjustment before driving the first robot 3 and moving the first arm 19. Then, the control device 6 stores the adjusted focal position. While moving the first arm 19, the control device 6 shoots with the focus of the photographic lens 21a fixed at the adjusted position.

  When driving the turntable 17 and the first joint 18, the first arm 19 moves. The distance that the first arm 19 moves from when a signal for stopping the driving to the turntable 17 and the first joint 18 until the first arm 19 stops is defined as a stop distance. This stop distance is the distance that the moving end 19a as the movable tip, which is the end of the first arm 19 opposite to the first joint 18, moves. At this time, the first imaging device 21 adjusts the focal point of the photographic lens 21a so that the moving end 19a and the moving end 19a are in focus in the traveling direction more than the stop distance. At this time, the distance between the in-focus position of the first imaging device 21 and the moving end 19a is set as a detection distance. The detection distance is set longer than the stop distance.

  A second joint 22 is disposed as a movable part in connection with the first arm 19. A second arm 23 is disposed as a movable part in connection with the second joint 22. The second arm 23 includes a fixed shaft 23a and a rotation shaft 23b, and the second arm 23 includes a rotation mechanism. And the 2nd arm 23 can rotate the rotating shaft 23b by making the longitudinal direction of the 2nd arm 23 into a rotating shaft.

  A second imaging device 24 is disposed on the upper side of the rotary shaft 23b via the rotary pedestal 20 in the drawing. Then, when the control device 6 rotates the rotating base 20, the direction in which the second imaging device 24 captures an image can be changed. Similar to the first imaging device 21, the second imaging device 24 has a photographic lens 24 a provided with a focus adjustment mechanism that can adjust the focus adjustment according to an instruction signal. The operator adjusts the focus of the photographic lens 24 a before moving the second arm 23. Then, the control device 6 stores the adjusted focal position. While moving the second arm 23, the control device 6 shoots with the focus of the photographic lens 24a fixed at the adjusted position.

  When driving the turntable 17, the first joint 18, and the second joint 22, the second arm 23 moves. The distance that the second arm 23 moves from when the signal for stopping the driving to the turntable 17, the first joint 18, and the second joint 22 is output until the second arm 23 stops is defined as the stop distance. This stop distance is a distance by which the moving end 23c as the movable tip, which is the end of the second arm 23 opposite to the second joint 22, moves. At this time, the second imaging device 24 adjusts the focal point of the photographic lens 24a so that the moving end 23c and the moving end 23c are in the traveling direction at a distance greater than the stop distance. At this time, the distance between the place where the second imaging device 24 is focused and the moving end 23c is set as a detection distance. The detection distance is set longer than the stop distance.

  A third joint 25 as a movable part is arranged in connection with the rotation shaft 23b of the second arm 23. A third arm 26 is arranged as a movable part in connection with the third joint 25. The third arm 26 includes a fixed shaft 26a and a rotation shaft 26b, and the third arm 26 can rotate the rotation shaft 26b with the longitudinal direction of the third arm 26 as a rotation axis.

  A third imaging device 27 is arranged on the upper side of the fixed shaft 26 a via the rotary pedestal 20. Then, when the control device 6 rotates the rotary base 20, the direction in which the third imaging device 27 captures an image can be changed. The third imaging device 27 includes a photographic lens 27a having a focus adjustment mechanism that can be switched between an automatic mode for automatically adjusting focus adjustment and a fixed mode for fixing to a preset focus position.

  The focus adjustment mechanism of the photographic lens 27a can adjust the focus according to the instruction signal in the same manner as the photographic lens 21a. The operator adjusts the focus of the photographic lens 27 a before moving the third arm 26. Then, the control device 6 stores the adjusted focal position. While moving the third arm 26, the control device 6 shoots with the focus of the photographic lens 27a fixed at the adjusted position.

  A hand portion 12 as a movable portion is arranged in connection with the rotation shaft 26 b of the third arm 26. When the turntable 17, the first joint 18, the second joint 22, and the third joint 25 are driven, the hand portion 12 moves. Then, the distance that the hand portion 12 moves from when a signal for stopping driving is output to the turntable 17, the first joint 18, the second joint 22, and the third joint 25 until the hand portion 12 stops is defined as a stop distance. . At this time, the third imaging device 27 adjusts the focal point of the photographic lens 27a in the fixed mode so that the focal point is located at a distance greater than or equal to the stop distance from the hand part 12 in the traveling direction of the hand part 12. At this time, the distance between the in-focus position of the third imaging device 27 and the tip of the hand portion 12 is defined as a detection distance. The detection distance is set longer than the stop distance.

  The hand portion 12 is formed long in a direction orthogonal to the rotation shaft 26 b of the third arm 26. The hand portion 12 is provided with a finger portion 28 as a pair of movable portions. The hand portion 12 includes a servo motor and a linear motion mechanism that is driven by the servo motor. The distance between the finger portions 28 can be changed by this linear motion mechanism.

  The first joint 18, the second joint 22, the second arm 23, the third joint 25, and the third arm 26 include a servo motor and a reduction mechanism inside, and the first arm 19, the second arm 23, and the third arm 26. Can be rotated and stopped with high angular accuracy. As described above, the robot has many joints and a rotation mechanism. In addition to these joints and rotation mechanism, the finger portion 28 is controlled so that the workpiece can be gripped and moved.

  The second robot 4 has the same configuration as the first robot 3. A fourth imaging device 29, a fifth imaging device 30, and a sixth imaging device 31 are arranged instead of the first imaging device 21, the second imaging device 24, and the third imaging device 27, respectively. The fourth image pickup device 29 and the fifth image pickup device 30 have photographic lenses 29a and 30a each having a focus adjustment mechanism capable of adjusting the focus adjustment according to the instruction signal in the same manner as the first image pickup device 21. And while driving the 2nd robot 4, the control apparatus 6 fixes the focus of the photographic lenses 29a and 30a. Similar to the third image pickup device 27, the sixth image pickup device 31 includes a photographic lens 31a having a focus adjustment mechanism capable of switching between an automatic mode for automatically adjusting the focus adjustment and a fixed mode for fixing to a preset focus position. Have. The focus adjustment mechanism of the photographic lens 31a can adjust the focus adjustment according to the instruction signal in the fixed mode.

  The photographic lenses 21a, 24a, 27a, 29a, 30a, and 31a preferably have a wide aperture and a shallow depth of field by using a wide-angle lens.

  FIG. 3 is an electric control block diagram of the picking apparatus. In FIG. 3, a control device 6 as a control unit of the picking device 1 includes a CPU (Central Processing Unit) 35 that performs various arithmetic processes as a processor and a memory 36 as a storage unit that stores various information.

  The first robot driving device 37, the second robot driving device 38, and the first imaging device 21 to the sixth imaging device 31 are connected to the CPU 35 via the input / output interface 39 and the data bus 40. Further, the supply device 2, the transport device 5, the input device 41, and the display device 42 are also connected to the CPU 35 via the input / output interface 39 and the data bus 40.

  The first robot drive device 37 is connected to the first robot 3 and drives the first robot 3. The first robot drive device 37 outputs information related to the posture of the first robot 3 to the CPU 35. When the CPU 35 instructs to move the workpiece 7, the workpiece 35 is gripped and moved.

  The second robot drive device 38 is connected to the second robot 4 and drives the second robot 4. The second robot drive device 38 outputs information related to the posture of the second robot 4 to the CPU 35. When the CPU 35 instructs to move the workpiece 7, the workpiece 35 is gripped and moved.

  Each of the imaging devices of the first imaging device 21 to the sixth imaging device 31 captures an image according to a signal instructed by the CPU 35, and then outputs captured image data to the memory 36.

  The supply device 2 moves or stops the belt 10 according to an instruction from the CPU 35. Then, the supply device 2 supplies the workpiece 7 to a range that can be reached by the hand portion 12 of the first robot 3. The conveying device 5 moves or stops the belt 10 according to an instruction from the CPU 35. Then, the work 7 moved by the second robot 4 is moved to the next process.

  The input device 41 is a device for inputting information on the shape of the workpiece 7 and various information such as operating conditions of the first robot 3 and the second robot 4. For example, it is a device that receives and inputs coordinates indicating the shape of the workpiece 7 from an external device (not shown). The display device 42 is a device that displays data and work status related to the workpiece 7, the first robot 3, and the second robot 4. An operator performs an input operation using the input device 41 based on the information displayed on the display device 42.

  The memory 36 is a concept including a semiconductor memory such as a RAM and a ROM, and an external storage device such as a hard disk and a DVD-ROM. Functionally, a storage area for storing the program software 43 in which the operation control procedure in the picking apparatus 1 is described is set in the memory 36. Furthermore, a storage area for storing work attribute data 44 that is information such as the shape and dimensions of the work 7 is also set in the memory 36. Further, there is a storage area for storing information related to the elements constituting the first robot 3 and the second robot 4 and robot-related data 45 which is information such as conditions for driving each movable part when the work 7 is moved. It is set in the memory 36. Furthermore, a storage area for storing image data taken by the first imaging device 21 to the sixth imaging device 31 and image data 46 that is image data after image processing is also set in the memory 36. Furthermore, a work area for the CPU 35, a storage area that functions as a temporary file, and other various storage areas are set in the memory 36.

  The CPU 35 performs control for picking the workpiece 7 after detecting the position of the workpiece 7 according to the program software 43 stored in the memory 36. As a specific function realization part, it has the robot control part 47 which performs the control for driving the 1st robot 3 and the 2nd robot 4, and moving the workpiece | work 7. FIG. In addition, it has a photographing control unit 48 that outputs photographing instructions to the first imaging device 21 to the sixth imaging device 31 to control the photographing operation. The imaging control unit 48 controls whether the focus adjustment of the third imaging device 27 and the sixth imaging device 31 is performed between the automatic mode and the fixed mode. Furthermore, it has an image calculation unit 49 that analyzes a photographed image and detects a subject approaching the first imaging device 21 to the sixth imaging device 31.

  In addition, there is an interference prevention control unit 50 that controls the operation of each robot so as to prevent interference when the first robot 3 and the second robot 4 approach each other. In addition, there is a workpiece position calculation unit 51 that detects the position of the workpiece 7 using a photographed image. In addition, a discharge material control unit 52 that controls operations of the supply device 2 and the transfer device 5 in cooperation with the operations of the first robot 3 and the second robot 4 is provided.

(Robot control method)
Next, a robot control method in an example of work in which the first robot 3 moves the hand portion 12 will be described with reference to FIGS. In the example of this work, the first robot 3 moves the hand 12 from the supply device 2 to the intermediate table 13 without interfering with the second robot 4. FIG. 4 is a flowchart showing the hand moving operation. 5 to 8 are schematic diagrams for explaining a robot control method in the hand moving operation.

  In the flowchart shown in FIG. 4, step S1 corresponds to a photographing process. This is a process in which the imaging device takes a picture with the focus of the photographic lens fixed. Next, the process proceeds to step S3. Step S2 corresponds to a moving process. This is a process in which the robot controller moves the hand part toward the target location. Next, the process proceeds to step S3. Step S1 and step S2 are performed in parallel. Step S3 corresponds to an image determination process. This is a step of determining whether there is a subject approaching a movable part such as a hand part using an image taken by the imaging device. When there is a subject approaching a movable part such as a hand, a place where the image is in focus is formed. When the image is in focus, the process proceeds to step S4. When the image is not in focus, the process proceeds to step S5.

  Step S4 corresponds to an interference prevention step. This is a step of controlling the movable part so that the subject and the imaging device do not approach each other. Next, the process proceeds to step S1 and step S2. Step S5 corresponds to an arrival determination step. This is a step of determining whether or not the hand has reached the target point. When the hand portion has not reached the target point, the process proceeds to step S1 and step S2. When the hand reaches the target point, the hand moving operation is terminated.

  Next, the robot control method in the hand moving operation will be described in detail with reference to FIGS. 5 to 8 in association with the steps shown in FIG. FIG. 5A to FIG. 5B are diagrams corresponding to the photographing process in step S1 and the moving process in step S2. As shown in FIG. 5A, in step S <b> 1 and step S <b> 2, the hand portion 12 of the first robot 3 moves from above the supply device 2 toward the intermediate table 13. The workpiece 7 is gripped by the hand portion 12. The imaging control unit 48 drives the rotary pedestal 20 to direct the direction in which the third imaging device 27 captures an image in the traveling direction of the hand unit 12. Then, while the workpiece 7 is moving, the imaging control unit 48 outputs an instruction to the third imaging device 27 to perform imaging.

  As a result, as shown in FIG. 5B, the first image 55 is taken. Since the second robot 4 is positioned in the traveling direction of the hand portion 12, an image of the second robot 4 is captured in the first image 55. Since the second robot 4 is located at a location away from the focal length of the third imaging device 27, the first image 55 is a defocused image with an unclear image contour.

  FIG. 5C is a diagram corresponding to the image determination process in step S3. FIG. 5C shows a line graph obtained by differentiating the luminance distribution and the luminance distribution contour in the first image. The first luminance distribution line 56 in the upper part of the figure shows the luminance distribution on the A-A ′ line of the first image 55 shown in FIG. The vertical axis indicates the luminance, and the upper side has a higher luminance than the lower side. The horizontal axis indicates the location on the A-A ′ line. A first luminance differential line 57 in the lower part of the figure indicates a line obtained by differentiating the first luminance distribution line 56 and calculating an absolute value. The vertical axis represents the differential absolute value, and the change in luminance is larger on the upper side than on the lower side.

  When the outline of the first image 55 is clear, the first luminance distribution line 56 is a line having a large change. The first luminance differential line 57 also shows a high peak value. Since the outline of the first image 55 is unclear, the first luminance distribution line 56 is a gently changing line. The peak of the first luminance differential line 57 is low. The proximity determination line 58 is a line for determining the peak value of the first luminance differential line 57. The peak value of the luminance differential line when the distance between the third imaging device 27 and the second robot 4 as the subject is a predetermined distance is shown. When the first luminance differential line 57 is lower than the proximity determination line 58, it can be determined that the distance between the third imaging device 27 and the second robot 4 that is the subject is greater than the focal length of the photographic lens 27a. In this example, the locations along the line A-A ′ are analyzed, but the analysis is performed at all locations of the first image 55.

  In the image determination step of step S3, it is determined that the photographed image is not in focus. Then, the process proceeds to step S5. In the arrival determination step of step S5, since the hand portion 12 has not reached the intermediate stage 13, determination is made to proceed to step S1 and step S2.

  FIGS. 6A to 6B are diagrams corresponding to the photographing process in step S1 and the moving process in step S2. As shown in FIG. 6A, in step S <b> 1 and step S <b> 2, the hand portion 12 of the first robot 3 moves from above the supply device 2 toward the intermediate table 13. Then, while the workpiece 7 is moving, the imaging control unit 48 outputs an instruction to the third imaging device 27 to perform imaging.

  As a result, as shown in FIG. 6B, the second image 59 is taken. Since the second robot 4 is positioned in the traveling direction of the hand portion 12, an image of the second robot 4 is captured in the second image 59. Since the third imaging device 27 is closer to the second robot 4 than when the first image 55 is taken, the image outline of the second image 59 is clearer than that of the first image 55. However, since the second robot 4 is located at a location away from the focal length of the third imaging device 27, the second image 59 is a defocused image with unclear image contours.

  FIG. 6C is a diagram corresponding to the image determination process in step S3. FIG. 6C shows a graph of a line obtained by differentiating the luminance distribution and the luminance distribution outline in the second image. The second luminance distribution line 60 in the upper part of the figure shows the luminance distribution on the B-B ′ line of the second image 59 shown in FIG. The vertical axis indicates the luminance, and the upper side has a higher luminance than the lower side. The horizontal axis indicates the location on the B-B ′ line. A second luminance differential line 61 in the lower part of the figure indicates a line obtained by differentiating the second luminance distribution line 60 and calculating an absolute value. The vertical axis represents the differential absolute value, and the change in luminance is larger on the upper side than on the lower side.

  Since the outline of the second image 59 is clearer than that of the first image 55, the second luminance distribution line 60 is a line having a large change compared to the first luminance distribution line 56. The peak of the second luminance differential line 61 is higher than the peak of the first luminance differential line 57. However, since the second luminance differential line 61 is lower than the proximity determination line 58, it can be determined that the distance between the third imaging device 27 and the second robot 4 that is the subject is greater than the focal length of the photographic lens 27a.

  In the image determination step of step S3, it is determined that the image is not in focus. Then, the process proceeds to step S5. In the arrival determination step of step S5, since the hand portion 12 has not reached the intermediate stage 13, determination is made to proceed to step S1 and step S2.

  FIG. 7A to FIG. 7B are diagrams corresponding to the photographing process in step S1 and the moving process in step S2. As shown in FIG. 7A, in step S <b> 1 and step S <b> 2, the hand portion 12 of the first robot 3 moves from above the supply device 2 toward the intermediate table 13. Then, while the workpiece 7 is moving, the imaging control unit 48 outputs an instruction to the third imaging device 27 to perform imaging.

  As a result, as shown in FIG. 7B, the third image 62 is taken. Since the second robot 4 is positioned in the traveling direction of the hand portion 12, an image of the second robot 4 is captured in the third image 62. Since the third imaging device 27 is closer to the second robot 4 than when the second image 59 is taken, the third image 62 has a clearer image outline than the second image 59.

  FIG. 7C is a diagram corresponding to the image determination process in step S3. FIG. 7C shows a graph of lines obtained by differentiating the luminance distribution and the luminance distribution contour in the third image 62. The third luminance distribution line 63 in the upper part of the figure indicates the luminance distribution on the C-C ′ line of the third image 62 shown in FIG. The vertical axis indicates the luminance, and the upper side has a higher luminance than the lower side. The horizontal axis indicates the location on the C-C ′ line. A third luminance differential line 64 in the lower part of the figure indicates a line obtained by differentiating the third luminance distribution line 63 and calculating an absolute value. The vertical axis represents the differential absolute value, and the change in luminance is larger on the upper side than on the lower side.

  Since the outline of the third image 62 is clearer than that of the second image 59, the third luminance distribution line 63 is a line having a large change compared to the second luminance distribution line 60. The peak of the third luminance differential line 64 is higher than the peak of the second luminance differential line 61. Since the third luminance differential line 64 is higher than the proximity determination line 58, it can be determined that the distance between the third imaging device 27 and the second robot 4 as the subject is the focal length of the photographic lens 27a. In the image determination step of step S3, it is determined that the image in the third image 62 is a focused image in focus. Then, the process proceeds to step S4.

  FIG. 8A and FIG. 8B are diagrams corresponding to the interference prevention process in step S4. As shown in FIG. 8A, in step S4, the interference prevention control unit 50 outputs to the robot control unit 47 an instruction to reverse the direction in which the hand portion 12 of the first robot 3 moves. Then, the imaging control unit 48 drives the rotary base 20 so that the direction of the third imaging device 27 is directed toward the supply device 2. Subsequently, the robot control unit 47 moves the hand portion 12 of the first robot 3 toward the supply device 2. At this time, the movement is stopped when there is a place where the image captured by the third imaging device 27 is in focus. As a result, the distance between the hand portion 12 and the second robot 4 becomes longer.

  Next, the robot controller 47 drives the second robot 4 to move the hand portion 12 of the second robot 4 from above the intermediate platform 13 toward the transport device 5. At this time, the second robot 4 repeats Step S1, Step S2, Step S3, and Step S5. In step S1, the imaging control unit 48 rotates the rotating base 20 of the fifth imaging device 30 to change the direction in which the fifth imaging device 30 captures the image to the direction in which the hand 12 advances. Then, the fifth imaging device 30 moves while confirming that there is no in-focus place in the image captured.

  When the second robot 4 moves the workpiece 7, the second robot 4 moves along a trajectory in which the vicinity of the hand portion 12 and the third joint 25 is the outermost periphery. Therefore, there is a high possibility that the vicinity of the hand portion 12 and the third joint 25 interferes with the object. The imaging control unit 48 uses the sixth imaging device 31 to image the vicinity of the hand portion 12. Further, the imaging control unit 48 uses the fifth imaging device 30 to image the vicinity of the third joint 25. Then, the CPU 35 detects an object that approaches the vicinity of the hand portion 12 and the third joint 25.

  As a result, as shown in FIG. 8B, the second robot 4 is not moved from above the intermediate platform 13. Thereafter, the first robot 3 moves from step S4 to step S1 and step S2, and starts to move the hand portion 12. Subsequently, the first robot 3 moves the hand portion 12 by repeating Step S1, Step S2, Step S3, and Step S5. The second robot 4 also moves the hand portion 12 by repeating Step S1, Step S2, Step S3, and Step S5.

  As a result, as shown in FIG. 8C, the hand portion 12 of the first robot 3 reaches the intermediate base 13. Then, in the arrival determination step of step S5, it is determined that the target point has been reached, and the hand moving operation is terminated. Similarly, the hand portion 12 of the second robot 4 reaches the transfer device 5. Then, in the arrival determination step of step S5, it is determined that the target point has been reached, and the hand moving operation is terminated.

As described above, this embodiment has the following effects.
(1) According to the present embodiment, the focus of the third imaging device 27 is fixed in the photographing process of step S1. Therefore, the range in which a focused image can be captured is limited. When a focused image can be detected in the captured first image 55 to third image 62, it is determined that the subject is present at the focal length of the photographic lens 27 a in the third imaging device 27.

  When it is determined in the image determination step of step S3 that the subject is located at a location where the third imaging device 27 and the photographic lens 27a are separated from each other, the process proceeds to the interference prevention step of step S4. In step S4, the interval between the hand 12 and the second robot 4 as the subject is not narrowed. Therefore, it is possible to prevent the hand portion 12 and the second robot 4 from interfering with each other.

  (2) According to this embodiment, when the 1st robot 3 moves the hand part 12, the hand part 12 becomes a movable front-end | tip part which is a part which moves the outermost periphery of the movable range. In step S3, it is detected whether or not a subject is present at a predetermined distance from the hand portion 12. When the subject approaches the movable range, the possibility that the location of the hand portion 12 approaches the subject is higher than the possibility that a location other than the hand portion 12 approaches the subject. Therefore, it is possible to increase the possibility of detecting a subject approaching the movable part, as compared with the case where the imaging apparatus captures a place near the place other than the hand part 12.

  (3) According to the present embodiment, the first robot 3 includes a plurality of movable parts and an imaging device. Therefore, the first robot 3 can change its posture. At this time, depending on how the movable part is moved, the movable tip part, which is the part that moves on the outermost periphery of the movable range, is replaced. Also at this time, it is possible to increase the possibility that the imaging device detects a subject approaching the movable tip by changing the imaging device that photographs the movable tip.

  (4) According to the present embodiment, each imaging device is adjusted so as to be focused on a location that is more than the stop distance from the movable tip. Then, it is detected whether or not there is a subject at that place. When there is a subject, the distance between the subject and the movable tip is greater than the stop distance. Accordingly, it is possible to prevent the movable portion and the subject from interfering when the movable portion is stopped.

In addition, this embodiment is not limited to embodiment mentioned above, A various change and improvement can also be added. A modification will be described below.
(Modification 1)
In the embodiment, the first robot 3 detects that the object approaches the hand 12 using the third imaging device 27. The imaging devices of the first imaging device 21, the second imaging device 24, and the third imaging device 27 may be moved in parallel. An object approaching each movable part can be detected.

(Modification 2)
In the above-described embodiment, vertical articulated robots are used for the first robot 3 and the second robot 4, but the present invention is not limited to the robot form. Various types of robots such as a horizontal articulated robot, an orthogonal robot, and a parallel link robot can be employed.

(Modification 3)
In the embodiment, a luminance differential line such as the first luminance differential line 57 is calculated to determine whether the image is in focus. The method for detecting whether the image is in focus is not limited to this. Spectrum analysis may be performed on the luminance distribution line such as the first luminance distribution line 56 at a spatial frequency. And you may judge using distribution of a frequency. The spectrum analysis may be one-dimensional or two-dimensional analysis. In the case of the one-dimensional case, the amount of calculation is smaller than in the case of the two-dimensional case, so that analysis can be performed in a short time. In the analysis of the two-dimensional analysis, since it is possible to detect the presence / absence of a focused place with respect to all the places of the image, it is possible to judge with high quality.

(Modification 4)
In the embodiment, the hand portion 12 of the first robot 3 is a movable tip portion, and the third imaging device 27 detects a subject approaching the hand portion 12. When the third joint 25 becomes a movable tip, a subject that approaches the third joint 25 may be detected using the second imaging device 24. Further, when the second joint 22 becomes a movable tip, a subject that approaches the second joint 22 may be detected using the first imaging device 21. When the movable part of the first robot 3 moves, it is possible to detect an object that approaches the place that becomes the movable tip part.

  DESCRIPTION OF SYMBOLS 2 ... Supply apparatus, 3 ... 1st robot, 4 ... 2nd robot as a to-be-photographed object, 12 ... Hand part as a movable part and a movable front-end | tip part, 17 ... Turntable as a movable part, 18 ... 1st as a movable part Joints 19a, 23c ... moving end as movable tip, 21 ... first imaging device, 22 ... second joint as movable portion, 24 ... second imaging device, 25 ... third joint as movable portion, 26 ... Third arm as movable part, 27... Third imaging device, 28. Finger part as movable part, 29... Fourth imaging device, 30. 59 ... 2nd image, 62 ... 3rd image.

Claims (4)

A photographing step of photographing a subject and generating an image using an imaging device installed on a movable part of the robot and having a fixed focus;
A moving step of moving the movable part;
An image determination step of detecting whether a focused image, which is an image focused on the image, is taken;
An interference prevention method for a robot, comprising: an interference prevention step that does not narrow a distance between the movable portion and the subject when the focused image is captured. The robot interference prevention method according to claim 1,
A place where the outermost periphery of the movable range of the movable part moves is a movable tip part,
A method for preventing interference of a robot, characterized in that the imaging device is adjusted so that the imaging device is focused at a position away from the movable tip by a predetermined distance. The robot interference prevention method according to claim 2,
The robot includes a plurality of movable parts, and the robot includes a plurality of movable tip parts and the imaging device. The robot interference prevention method according to claim 3,
The distance between the movable tip and the place where the imaging device is in focus is the detection distance,
After determining to stop the movable tip, when the distance that the movable tip moves while stopping the movable tip is a stop distance,
The method for preventing interference of a robot, wherein the detection distance is a distance greater than the stop distance.