JP2021030391A - Attitude control device, work-piece processor, and work-piece attitude control method - Google Patents

Abstract

To provide an attitude control device which can adequately control a position of a work-piece.SOLUTION: An attitude control device 10 comprises a multi-joint robot 20, an imaging unit 40, and a control part 56. The control part 56 comprises: an image processing part 53 which acquires depth information from a picked-up image for control imaged by the imaging unit 40 on all of a plurality of focus areas 62A to 62D which are set in an imaging visual field 61A of a work-piece 60; a calculation processing part 51 which operates the multi-joint robot 20 on the basis of all pieces of depth information acquired by the image processing part 53, thereby determining a focusing attitude focusing on all of the plurality of focus areas 62A to 62D, and changing an attitude of the work-piece 60 to acquire a displacement amount from an operation start attitude to the focusing attitude; and a robot control part 55 which displaces the multi-joint robot 20 to a focusing position at which the work-piece 60 takes the focusing attitude on the basis fo the displacement amount acquired by the calculation processing part 51.SELECTED DRAWING: Figure 2

Description

The present invention relates to an attitude control device, a work processing device, and a work posture control method.

An inspection method is known in which a work is held by an end effector attached to the tip of a robot arm, an image is taken by an imaging device, and the obtained image is image-processed to perform an image inspection of the work. In such an inspection method, if the image is taken in a state where the workpiece does not face the imaging device, the focus may be out of focus and the inspection may not be performed properly.

Here, as a method of controlling the posture of the robot, the tip of the robot arm is rotated around the tip axis with the outer peripheral surface of the measuring work gripped by the robot hand as the end effector abutting against the reference jig. The robot hand is centered by calculating the correction amount based on the eccentricity (see Patent Document 1), and while operating the robot arm, a mark indicating the center position of the robot hand is imaged and used as the movement trajectory of the mark. Based on this, a technique (see Patent Document 2) has been proposed in which the positional deviation of the central axis of the robot hand is calculated to correct the trajectory data of the robot arm.

Japanese Unexamined Patent Publication No. 2016-168651 JP-A-2017-124468

The above technique corrects the behavior of the robot by quantifying the posture of the end effector and using it as a correction value. For example, when the holding state of the work with respect to the end effector is deviated, the end is used. Evaluating the posture of the effector does not necessarily lead to proper control of the position of the work.

The posture control device disclosed by the present specification includes an articulated robot including a robot arm having a plurality of joints, an end effector attached to the tip of the robot arm to hold a work, and a robot arm held by the end effector. The work is provided with an image pickup device that captures the image of the work, and a control unit that controls the articulated robot and the image pickup device. The control unit uses the control image captured by the image pickup device to obtain the work. By operating the articulated robot based on the image processing unit that acquires depth information at all of the plurality of determination positions set in the imaging field of the camera and all the depth information acquired by the image processing unit. , The arithmetic processing unit that determines the focusing posture to be focused at all of the plurality of determination positions, changes the posture of the work, and acquires the displacement amount from the operation start posture to the focusing posture. It includes an operation control unit that displaces the end effector to a focusing position in which the work takes the focusing posture based on the displacement amount acquired by the arithmetic processing unit.

Further, the work posture control method disclosed in the present specification is a work posture held by an articulated robot including a robot arm having a plurality of joints and an end effector attached to the tip of the robot arm. A method of controlling the work, that is, a transport step of holding the work by the end effector and transporting the work to an imaging position, an imaging step of imaging the work by an imaging device, and a control captured image captured in the imaging step. From the image processing step of acquiring depth information at all of the plurality of determination positions set in the imaging field of the work, and the articulated robot based on all the depth information acquired in the image processing step. A calculation process that determines the focusing posture to be focused at all of the plurality of determination positions by operating the work, changes the posture of the work, and acquires the amount of displacement from the operation starting posture to the focusing posture. It includes a step and an operation control step of displacementing the end effector to a focusing position where the work takes the focusing posture based on the displacement amount acquired in the arithmetic processing step.

According to the attitude control device disclosed by the present specification and the attitude control method of the work, the position of the work can be appropriately controlled.

FIG. 1 is a front view of the image inspection device of the embodiment. FIG. 2 is a block diagram showing an electrical configuration of the image inspection device of the embodiment. FIG. 3 is a flowchart showing a flow of processing in which the posture of the work is controlled by the image inspection device of the embodiment and the image inspection is performed. FIG. 4 is a flowchart showing the flow of the autofocus process in the embodiment. FIG. 5 is a front view of the work of the embodiment. FIG. 6 is a diagram showing a focus area set in the imaging field of view in the work of the embodiment. FIG. 7 is a plan view showing a state in which the work held by the end effector does not face the image pickup apparatus in the embodiment. FIG. 8 is a side view showing a state in which the work held by the end effector does not face the image pickup apparatus in the embodiment. FIG. 9 is a partially enlarged plan view showing a state in which the work held by the end effector faces the image pickup apparatus in the embodiment. FIG. 10 is a partially enlarged side view showing a state in which the work held by the end effector faces the image pickup apparatus in the embodiment.

[Outline of Embodiment]
The posture control device disclosed by the present specification includes an articulated robot including a robot arm having a plurality of joints, an end effector attached to the tip of the robot arm to hold a work, and a robot arm held by the end effector. The work is provided with an image pickup device that captures the image of the work, and a control unit that controls the articulated robot and the image pickup device. The control unit uses the control image captured by the image pickup device to obtain the work. By operating the articulated robot based on the image processing unit that acquires depth information at all of the plurality of determination positions set in the imaging field of the camera and all the depth information acquired by the image processing unit. , The arithmetic processing unit that determines the focusing posture to be focused at all of the plurality of determination positions, changes the posture of the work, and acquires the displacement amount from the operation start posture to the focusing posture. It includes an operation control unit that displaces the end effector to a focusing position in which the work takes the focusing posture based on the displacement amount acquired by the arithmetic processing unit.

Further, the work posture control method disclosed in the present specification is a work posture held by an articulated robot including a robot arm having a plurality of joints and an end effector attached to the tip of the robot arm. A method of controlling the work, that is, a transport step of holding the work by the end effector and transporting the work to an imaging position, an imaging step of imaging the work by an imaging device, and a control captured image captured in the imaging step. From the image processing step of acquiring depth information at all of the plurality of determination positions set in the imaging field of the work, and the articulated robot based on all the depth information acquired in the image processing step. A calculation process that determines the focusing posture to be focused at all of the plurality of determination positions by operating the work, changes the posture of the work, and acquires the amount of displacement from the operation starting posture to the focusing posture. It includes a step and an operation control step of displacementing the end effector to a focusing position where the work takes the focusing posture based on the displacement amount acquired in the arithmetic processing step.

According to the above configuration, since the posture of the work itself is directly evaluated to determine the focusing posture, the posture control of the work is compared with the conventional technique in which the posture of the end effector is evaluated and corrected. Can be done more appropriately.

Further, the work processing device disclosed by the present specification includes the above-mentioned attitude control device and a working unit that performs a predetermined work on the work while the work is held in the in-focus posture.

In the work processing device, an image inspection in which the working unit processes an image for inspection taken by the image pickup device while the work is held in the in-focus position and executes an image inspection of the work. It may be a department.

According to such a configuration, the work is imaged by the imaging device, the focusing posture is determined from the obtained control image, and then the image is taken again by the same imaging device while the work is held in the focusing posture. It is possible to obtain an image for inspection. As a result, it becomes easy to acquire an inspection image in which the entire visual field is in focus, and it becomes easy to appropriately perform an image inspection.

[Details of Embodiment]
Specific examples of the techniques disclosed herein will be described below with reference to the drawings. It should be noted that the present invention is not limited to these examples, and is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

<Embodiment>
The embodiment will be described with reference to FIGS. 1 to 10.

(Overall configuration of image inspection device 1)
The image inspection device 1 (an example of the work processing device) of the present embodiment is a device for performing an image inspection of the work 60, and as shown in FIG. 1, an articulated robot for transporting and holding the work 60. 20. An image pickup device 40 for taking an image of the work 60 and the like are provided. The work 60 to be image-inspected is, for example, an LED substrate.

As shown in FIG. 1, the articulated robot 20 includes a vertical articulated robot arm 21 and an end effector 31 attached to the tip of the robot arm 21 to hold the work 60.

The robot arm 21 includes a base portion 23 fixed to the gantry 22 and a plurality of links 24 for transmitting displacement and force, and the base portion 23, the links 24, and adjacent links 24 swing or swing at joints 25. It is rotatably connected. In the present embodiment, the robot arm 21 includes 6-axis joints 25 having 3 swinging axes and 3 rotating axes, and a joint driving device (not shown) is incorporated in each joint 25.

The end effector 31 is a gripping hand that includes a plurality of (two in this embodiment) gripping portions 32, and grips and holds the work 60. The end effector 31 is attached to a link 24 on the opposite side of the base portion 23, that is, a link 24 located at the tip of the robot arm 21 via a force sensor. The two grips 32 are displaceable in the direction of being close to each other and separated from each other, and the work 60 is gripped by moving (closing) the two grips 32 in the direction of approaching each other, and the two grips 32 are held. The work 60 is released by moving (opening operation) in a direction away from each other.

The image pickup device 40 is a device for taking an image of the work 60 held by the end effector 31, and includes an image sensor such as a CCD or CMOS, a light source for illuminating the work 60, and the like.

(Electrical configuration of image inspection device 1)
Next, the electrical configuration of the image inspection device 1 will be described with reference to FIG. The image inspection device 1 has a main control unit 50, and the main control unit 50 controls and controls the entire image inspection device 1. The main control unit 50 includes an arithmetic processing unit 51. The articulated robot 20 and the imaging device 40 are connected to the main control unit 50.

A robot control unit 55 (an example of an operation control unit) is connected to the articulated robot 20, and an image pickup control unit 52 is connected to the image pickup device 40. The operation of the articulated robot 20 is controlled by the robot control unit 55. The image pickup control unit 52 is configured to capture an image signal output from the image pickup device 40, and has an image processing unit 53 that analyzes an image for control based on the captured image signal and an image processing unit 53 for inspection. It includes an image inspection unit 54 (an example of a working unit) that analyzes captured images.

The main control unit 50, the image processing unit 53, and the robot control unit 55 form a control unit 56. Further, the control unit 56, the image pickup device 40, and the articulated robot 20 constitute the attitude control device 10.

The image processing unit 53 analyzes the control captured image captured by the imaging device 40 and calculates the contrast value. The arithmetic processing unit 51 determines the focusing posture of the work 60 based on the peak value of the contrast value, and calculates the displacement amount of the work 60 based on the operation start posture and the focusing posture. The robot control unit 55 displaces the end effector 31 based on the calculated displacement amount. Hereinafter, a detailed description will be given.

(Operation mode of image inspection device 1)
The process of controlling the posture of the work 60 and performing the image inspection by the image inspection device 1 will be described with reference to FIGS. 3 and 4.

The robot control unit 55 drives and controls the articulated robot 20 to hold the work 60 in the end effector 31 and move the work 60 to the imaging position, that is, the front position of the imaging device 40 (step S10: transfer step). Here, the surface of the work 60 to be imaged (imaging surface 60F: see FIG. 7) is divided into a plurality of imaging fields of view 61 as shown in FIG. 5, and the robot control unit 55 determines among them. The articulated robot 20 is driven and controlled so that the one (for example, the imaging field of view 61A in the upper right of FIG. 5) is located in front of the imaging device 40. In the following description, when distinguishing each imaging field of view, subscripts A and B are added to the codes of the imaging field of view, and when generically referred to without distinction, no subscript is added to the code. And.

Next, the image pickup control unit 52 controls the image pickup device 40 to take an image in the image pickup field of view 61A of the work 60, and obtains an image capture image (step S20). The image processing unit 53 of the image pickup control unit 52 performs image processing on the obtained captured image, and applies the plurality of focus areas 62A, 62B, 62C, 62D (an example of the determination position) set in the imaging field of view 61A. It is analyzed whether or not it is impatient (step S30). In the present embodiment, one imaging field of view 61A having a rectangular outer shape is divided into four vertically and horizontally, and focus areas 62A, 62B, 62C, and 62D are set for each division (see FIG. 6).

Here, if the work 60 is held in the normal holding posture by the end effector 31, the imaging surface 60F faces the imaging device 40. However, if the holding posture of the work 60 with respect to the end effector 31 deviates from the normal holding posture, the imaging surface 60F does not face the imaging device 40. In the examples shown in FIGS. 7 and 8, if the work 60 is held in the normal holding posture by the end effector 31, the imaging surface 60F should be located in the XZ plane of FIGS. 7 and 8. Since the holding posture of the work 60 with respect to the end effector 31 deviates from the normal holding posture, the imaging surface 60F is tilted with respect to the XZ plane. When such a situation occurs, the obtained image is partially out of focus. That is, at least a part of the focus areas 62A, 62B, 62C, and 62D will not be in focus. In the example shown in FIG. 6, it is determined that only one focus area 62A (upper right of FIG. 6) is in focus, and the other focus areas 62B, 62C, and 62D are determined not to be in focus. There is.

When it is determined that at least one of the plurality of focus areas 62A, 62B, 62C, and 62D is not in focus, the arithmetic processing unit 51 adjusts the focusing posture of the work 60 by autofocus (AF) processing. Determine (step S40). In the present embodiment, the AF process is executed by the contrast autofocus (AF) method. In the contrast autofocus (AF) method, imaging is performed multiple times while changing the distance between the lens and the subject, and the contrast value (AF evaluation value: an example of depth information) of the obtained image is calculated, and the contrast value is calculated. This is a method of determining that the subject is in focus when it reaches the maximum.

When the AF process is started, the arithmetic processing unit 51 first acquires the current posture of the work 60 and stores it as the operation start posture (step S41).

Next, the scanning process is executed (step S42). Specifically, the main control unit 50 controls the robot control unit 55 to drive the articulated robot 20, controls the image pickup control unit 52 while gradually changing the position of the work 60, and controls the image pickup field 61A. A plurality of control captured images are captured (imaging step). The image processing unit 53 performs image processing on the obtained plurality of control captured images, and calculates a contrast value for each of the focus areas 62A, 62B, 62C, and 62D (step S43: image processing step).

The arithmetic processing unit 51 determines whether or not the peak value of the contrast value is detected for each of the focus areas 62A, 62B, 62C, and 62D (step S44). If it is determined that the peak value has not been detected, the processes from step S42 to step S44 are repeated until the peak value is detected. The contrast value information calculated by the image processing unit 53 is fed back to the robot control unit 55 and reflected in the drive control of the articulated robot 20 during the scanning process.

When the arithmetic processing unit 51 determines that the peak value of the contrast value is detected for all the focus areas 62A, 62B, 62C, 62D, the contrast value becomes the peak value for all the focus areas 62A, 62B, 62C, 62D. The posture of the work 60 is acquired with 6 degrees of freedom, and this posture is determined as the focusing posture (step S45). Next, the arithmetic processing unit 51 calculates the amount of displacement of the work 60 from the operation start posture to the focusing posture (step S46). The step of repeating the processes from step S42 to step S44 to detect the peak value of the contrast value, and steps S45 and S46 are examples of the arithmetic processing steps.

After the displacement amount is calculated, the robot control unit 55 displaces the end effector 31 to the focusing position where the work 60 takes the focusing posture based on the displacement amount (step S50: motion control step). When the end effector 31 is displaced to the in-focus position, the imaging surface 60F of the work 60 faces the imaging device 40 as shown in FIGS. 7 and 8.

Then, an image inspection is performed (step S60). The image pickup control unit 52 controls the image pickup device 40 to take an image in the image pickup field of view 61A of the work 60, and obtains an image for inspection. The image inspection unit 54 performs image processing on the obtained captured image for inspection to determine whether or not there is a defect or the like in the imaging field of view 61A. In this way, the image inspection is completed for one imaging field of view 61A.

Next, the robot control unit 55 drives and controls the articulated robot 20 to displace the end effector 31 so that the other imaging field of view 61B adjacent to one imaging field of view 61A is located in front of the imaging device 40. .. At this time, the arithmetic processing unit 51 reflects the information on the focusing posture of one imaging field of view 61A to the other imaging field of view 61B, so that the displacement amount of the work 60 is adjusted so as to focus in the imaging field of view 61B. calculate. Then, the robot control unit 55 displaces the end effector 31 based on the calculated displacement amount. Next, an image inspection is performed on the other imaging field of view 61B. Similarly, an image inspection is performed on all imaging fields of view 61.

(Action effect)
As described above, according to the present embodiment, the posture of the work 60 itself is directly evaluated to determine the focusing posture, so that the posture of the end effector is evaluated and corrected as compared with the conventional technique. , The attitude control of the work 60 can be performed more appropriately.

Further, when the work 60 is photographed by the imaging device 40 and the focusing posture is determined from the obtained control image, the work 60 is held in the focusing posture and the work 60 is imaged again by the same imaging device 40 for inspection. It is possible to obtain a captured image for use. As a result, it becomes easy to acquire an inspection image in which the entire visual field is in focus, and it becomes easy to appropriately perform an image inspection.

<Other Embodiments>
(1) In the above embodiment, the LED work is exemplified as the work 60, but the type of the work is arbitrary, and for example, a wireless communication module substrate may be used.
(2) In the above embodiment, the gripping hand is illustrated as the end effector 31, but the end effector may be, for example, a suction hand.
(3) The division mode of the imaging field of view can be arbitrarily set according to the size and shape of the work. Further, the entire imaging field of view may be used as one imaging field of view without dividing the imaging field of view.
(4) The selection of the imaging field of view used to determine the focusing posture is arbitrary, and for example, the imaging field of view located at the center of the plurality of imaging fields of view may be selected.
(5) In the above embodiment, the four focus areas 62A, 62B, 62C, and 62D are set, but the number and positions of the determination positions can be arbitrarily set according to the required attitude control accuracy.
(6) In the above embodiment, the focusing posture is determined by the contrast autofocus (AF) process, but the autofocus process may be executed by, for example, a phase difference autofocus method.
(7) In the above embodiment, the attitude control device 10 is applied to the image inspection device 1, but the attitude control device is applied to, for example, a processing device, and the working unit is a processing unit for processing the work. It doesn't matter.
(8) In the above embodiment, when the work 60 is displaced in order to perform an image inspection of another imaging field of view 61B, information on the focusing posture of one imaging field of view 61A is reflected in the other imaging field of view 61B. However, the focusing posture may be determined and the displacement amount may be calculated by individually performing the autofocus processing in all of the plurality of imaging fields.

1: Image inspection device (work processing device)
10: Attitude control device 20: Articulated robot 21: Robot arm 22: Stand 23: Base unit 24: Link 25: Joint 31: End effector 32: Grip unit 40: Image pickup device 50: Main control unit 51: Arithmetic processing unit 52 : Image control unit 53: Image processing unit 54: Image inspection unit (working unit)
55: Robot control unit (motion control unit)
56: Control unit 60: Work 60F: Imaging surface 61: Imaging field of view 61A: One imaging field of view 61B: Other imaging fields of view 62A, 62B, 62C, 62D: Focus area (determination position)

Claims (4)

An articulated robot including a robot arm having a plurality of joints and an end effector attached to the tip of the robot arm to hold a work.
An imaging device that images the work held by the end effector, and
A control unit that controls the articulated robot and the imaging device is provided.
The control unit
An image processing unit that acquires depth information at all of a plurality of determination positions set in the imaging field of view of the work from the control captured image captured by the imaging device.
By operating the articulated robot based on all the depth information acquired by the image processing unit, the focusing posture to be focused at all of the plurality of determination positions is determined, and the posture of the work is changed. An arithmetic processing unit that acquires the amount of displacement from the operation start posture to the focusing posture.
An attitude control device including an operation control unit that displaces the end effector to a focusing position in which the work takes the focusing posture based on the displacement amount acquired by the arithmetic processing unit. The attitude control device according to claim 1 and
A work processing device including a work unit that performs a predetermined work on the work while the work is held in the focusing posture. The working part
The work according to claim 2, wherein the work is an image inspection unit that performs image processing on an inspection image captured by the image pickup apparatus while the work is held in the in-focus position and executes an image inspection of the work. Processing equipment. A method of controlling the posture of a work held by an articulated robot including a robot arm having a plurality of joints and an end effector attached to the tip of the robot arm.
A transfer process in which the work is held by the end effector and conveyed to the imaging position, and
An imaging process in which the work is imaged by an imaging device, and
An image processing step of acquiring depth information from the control captured image captured in the imaging step at all of a plurality of determination positions set in the imaging field of view of the work.
By operating the articulated robot based on all the depth information acquired in the image processing step, the focusing posture to be focused at all of the plurality of determination positions is determined, and the posture of the work is changed. An arithmetic processing process for acquiring the amount of displacement from the operation start posture to the in-focus posture.
A work posture control method comprising a motion control step of displace the end effector to a focusing position in which the work takes the focusing posture based on the displacement amount acquired in the arithmetic processing step.

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