Positioning device

Abstract

Reduce the travel time of the target object. [Solution] The system includes a moving mechanism 1 for moving a target object P1, an imaging unit 2 for photographing the target object P1, an image processing unit 4 that outputs position information D2 of the target object P1 based on image data D1 captured by the imaging unit 2, a first control unit 6 that controls the moving mechanism 1 to move the target object P1 to a target position P2 based on the position information D2, and an image size changing unit 71 that changes the size of the image data D1 output from the imaging unit P1 according to the positional relationship between the target object P1 and the target position P2.

Description

Technical Field

[0001] The present disclosure relates to a positioning device that positions a target object at a target position.

Background Art

[0002] Conventionally, in industrial machines such as manufacturing devices for electronic devices and various processing devices, a positioning device for a moving body has been used. As such a positioning device, for example, a component mounting device that produces an electronic substrate by mounting electronic components at predetermined positions on a printed circuit board is known.

[0003] For example, Patent Document 1 discloses a control system that realizes positioning using image processing at higher speed and higher precision. Specifically, the control system of Patent Document 1 executes a second control operation after executing a first control operation. In the first control operation, the image processing means acquires image data and specifies the position of a feature portion. The control means determines a control command for moving an object to an intermediate target position separated from the final target position by a predetermined margin distance by accelerating the object to a predetermined first speed and then decelerating it to a predetermined second speed smaller than the first speed based on the position of the specified feature portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, since the object (target object) is moved at a second speed smaller than the first speed from the intermediate target position to the final target position, the movement time of the object becomes long.

[0006] The present disclosure aims to provide a positioning device that can shorten the travel time of a target object. [Means for solving the problem]

[0007] To achieve the above objective, the positioning device according to this disclosure comprises a moving mechanism for moving a target object, an imaging unit for photographing the target object, an image processing unit that outputs position information of the target object based on image data captured by the imaging unit, a control unit that controls the moving mechanism to move the target object to a target position based on the position information, and an image size changing unit that changes the size of the image data output from the imaging unit according to the positional relationship between the target object and the target position. [Effects of the Invention]

[0008] According to this disclosure, the travel time of the target object can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing the configuration of the positioning device according to the first embodiment. [Figure 2] Block diagram of the positioning device according to the first embodiment. [Figure 3] An image showing an example of image data D1 according to the first embodiment. [Figure 4] An image showing an example of the setting screen for the first condition according to the first embodiment. [Figure 5] A schematic diagram showing the configuration of the positioning device according to the second embodiment. [Figure 6] An image showing an example of the setting screen for the first condition according to the second embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present disclosure will be described below with reference to the drawings. The following description of preferred embodiments is illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0011] (First Embodiment) Figure 1 is a schematic diagram showing the configuration of a positioning device according to the first embodiment. As shown in Figure 1, the positioning device according to this embodiment comprises a moving mechanism 1, an imaging unit 2, a light source 3, an image processing unit 4, a conversion unit 5, a first control unit 6, and a second control unit 7. In the following description, the height direction will be referred to as the Z direction, and the directions perpendicular to the Z direction will be referred to as the X direction and the Y direction.

[0012] The moving mechanism 1 is a moving mechanism that moves the target object P1 (workpiece) to the target position P2 by driving the stage 11. The target object P1 is, for example, an electronic component or an alignment mark. The target position P2 is the target position of the target object P1. In Figure 1, the target object P1 is shown as a circle, but it can be any shape. In Figure 1, for the sake of explanation, the target position P2 is shown as a dashed line (cross mark), but the target position P2 may or may not be an actual object. The target position P2 is, for example, the position where the target object P1 is imaged by the imaging unit 2 when the target object P1 is moved to the target position. In this case, the position of the target object P1 when it is moved to the target position P2 is imaged in advance, and this position of the target object P1 becomes the target position P2. That is, in this case, the target position P2 is not an actual object. Furthermore, in the case of bonding transparent workpieces, the target object P1 and target position P2 are attached to each workpiece. In this case, the workpieces are moved so that the relative positions of the target object P1 and target position P2 remain constant. That is, in this case, the target position P2 is actually attached. In this embodiment, however, the case where the target position P2 is not actually attached will be explained as an example.

[0013] The moving mechanism 1 comprises a stage 11 and drive units 12 and 13.

[0014] Stage 11 is a stage on which the target object P1 is placed. The stage 11 extends in the X direction and the Y direction and is formed in a substantially planar shape. Driving units 12 and 13 are attached to the stage 11. The driving unit 12 drives (moves) the stage 11 in the X direction (driving direction). The driving unit 13 drives (moves) the stage 11 in the Y direction (driving direction). The target object P1 placed on the stage 11 moves in the X direction and the Y direction on the stage 11 when the driving units 12 and 13 are driven. Although details will be described later, the driving units 12 and 13 are driven based on the control signals D71 and D72 output from the first control unit 6.

[0015] Also, the driving units 12 and 13 have sensors that detect displacement and speed in their driving directions. The driving unit 12 outputs speed information D81 indicating its speed in the X direction (driving direction) to the speed control unit 62a. The driving unit 13 outputs speed information D82 indicating its speed in the Y direction (driving direction) to the speed control unit 62b.

[0016] The imaging unit 2 images the target object P1 placed on the stage 11 at a predetermined cycle. Specifically, the imaging unit 2 is arranged above (in the Z direction) the stage 11 and is installed such that the imaging direction is directed toward the stage 11. In the present embodiment, since the target position P2 is not actually attached, the imaging unit 2 images the target object P1. However, when the target position P2 is actually attached, the imaging unit 2 images the target object P1 and the target position P2.

[0017] The imaging unit 2 outputs the imaging result to the image processing unit 4 as image data D1.

[0018] The light source 3 is a light source composed of an LED (Light-Emitting Diode) or the like. The light source 3 irradiates spot light on the target object P1 in accordance with the imaging timing of the imaging unit 2.

[0019] The image processing unit 4 is, for example, a computer or the like. The image processing unit 4 communicates with the imaging unit 2, the conversion unit 5, and the second control unit 7. The image processing unit 4 includes a position information generation unit 41.

[0020] Based on the image data D1 output from the imaging unit 2, the position information generation unit 41 generates position information D2 of the target object P1 (the position of the target object P1 in the X and Y directions).

[0021] The image processing unit 4 generates the position information D2 of the target object P1 based on the features given to the target object P1. For example, a predetermined mark (such as a cross or a circle) is given as a feature to the target object P1. Based on this mark, the image processing unit 4 generates the position information D2 of the target object P1 (identifies the position of the target object P1). Note that the feature given to the target object P1 may be a predetermined mark or a specific area such as a corner portion of the target object P1.

[0022] The conversion unit 5 converts the position information D2 of the target object P1 generated by the position information generation unit 41 into displacements (positions) in the driving directions (X and Y directions) of the driving units 12 and 13. Specifically, the conversion unit 5 converts the position (coordinates) of the target object P1 in the position information D2 into the position (coordinates) of the target object P1 in the driving directions of the driving units 12 and 13. For example, in this embodiment, the first reference position (coordinates) in the position information D2 is associated with the second reference position (coordinates) in the driving directions of the driving units 12 and 13. The conversion unit 5 converts the position of the target object P1 with respect to the first reference position in the position information D2 into the position of the target object P1 with respect to the second reference position in the driving directions of the driving units 12 and 13. That is, the conversion unit 5 generates displacement information D31 indicating the displacement (position) of the target object P1 in the X direction (driving direction of the driving unit 12) after conversion, and displacement information D32 indicating the displacement (position) of the target object P1 in the Y direction (driving direction of the driving unit 13) after conversion.

[0023] Displacement information D41 and D42 are data obtained by converting the target position P2 in the image captured by the imaging unit 2 to the target position P2 in the driving direction of the drive units 12 and 13. The image at this time is the image captured by the imaging unit 2 when the target object P1 is at the target position P2. For example, displacement information D41 and D42 are obtained by converting the target position P2 in the image data D1, relative to the first reference position, to the target position P2 relative to the second reference position in the driving direction of the drive units 12 and 13. Displacement information D41 shows the displacement (position) of the converted target position P2 in the X direction (driving direction of the drive unit 12). Displacement information D42 shows the displacement (position) of the converted target position P2 in the Y direction (driving direction of the drive unit 13).

[0024] The first control unit 6 is, for example, a computer. The first control unit 6 controls the operation of the drive units 12 and 13. Specifically, the first control unit 6 comprises position control units 61a and 61b and speed control units 62a and 62b.

[0025] As shown in Figure 1, the position control unit 61a generates a velocity command value D61 based on displacement information D31 and D41, which sets the difference between the displacement of the target object P in the X direction and the displacement of the target position of the target object P in the X direction to 0. The velocity control unit 62a generates a control signal D71 to control the drive unit 12 based on the velocity command value D61 and velocity information D81. The position control unit 61b generates a velocity command value D62 based on displacement information D32 and D42, which sets the difference between the displacement of the target object P in the Y direction and the displacement of the target position of the target object P in the Y direction to 0. The velocity control unit 62b generates a control signal D72 to control the drive unit 13 based on the velocity command value D62 and velocity information D82.

[0026] The second control unit 7 will be described later.

[0027] Figure 2 is a block diagram of the positioning device according to the first embodiment. In Figure 2,

[0028]

number

[0029] This is the displacement of the target object P1 in the X direction (displacement information D31),

[0030]

number

[0031] This is the displacement of the drive unit 12 in the driving direction (X direction),

[0032]

number

[0033] This is the speed of the drive unit 12 in the driving direction (X direction). Note that in Figure 2, the control system that controls the Y direction (position control unit 61b, speed control unit 62, and drive unit 13, etc.) is omitted from the illustration. The control system that controls the Y direction (position control unit 61b, speed control unit 62, and drive unit 13, etc.) is configured similarly to the control system that controls the X direction (position control unit 61a, speed control unit 62a, and drive unit 12, etc.) which will be described below, so the explanation will be omitted as appropriate.

[0034] The position control unit 61a generates a velocity command value D61 to make the difference between the displacement of the target object P1 in the X direction (driving direction of the drive unit 12) (displacement information D31) and the displacement of the target position P2 in the X direction (driving direction of the drive unit 12) (displacement information D41) zero.

[0035] Specifically, the position control unit 61a includes a position control controller 611. The position control controller 611 generates a velocity command value D61 based on displacement information D31 and displacement information D41.

[0036] The speed control unit 62a controls the drive unit 12 so that the speed command value D61 and the speed information D81 (speed of the drive unit 12 in the driving direction) are equal. Specifically, the speed control unit 62a includes a speed control controller 621. The speed control controller 621 generates a control signal D71 based on the speed command value D61 and the speed information D81. Based on the control signal D71, the drive unit 12 drives (moves) the stage 11 (target object P1) in the X direction.

[0037] As described above, the positioning device of this embodiment is configured with a feedback control system in which the displacement of the drive unit in the driving direction and the displacement of the target object P1 are fed back to the first control unit 6.

[0038] As shown in Figure 1, the second control unit 7 is, for example, a computer. The second control unit 7 controls the operation of the imaging unit 1 and the first control unit 6 based on the position information D2. The second control unit 7 includes an image size changing unit 71, a control gain changing unit 72 (control parameter changing unit), a display unit 73, an operation unit 74, and a setting unit 75.

[0039] The image resizing unit 71 outputs a resizing signal D10 to the imaging unit 1 based on the position information D2 received from the image processing unit 4 (position information generation unit 41). Specifically, the image resizing unit 71 generates a resizing signal D10 if the position of the target object P1 in the position information D2 satisfies the first condition. The imaging unit 1 reduces the size of the image data D1 to be output according to the resizing signal D10. At this time, the image resizing unit 71 outputs the resizing signal D10 to the position information generation unit 41. The position information generation unit 41 outputs the position information D2 according to the input resizing signal D10. The position information generation unit 41 outputs position information D2 that is not affected even if the output range of the image data D1 is changed by taking the resizing signal D10 into consideration. In this embodiment, it is assumed that the second control unit 7 has already received the position information D2 when the target object P1 is at the target position P2.

[0040] Figure 3 shows an example of image data D1 according to the first embodiment. In Figure 3, the image data D1 before receiving the resizing signal D10 is shown as region S1 (dashed line), and the image data D1 after receiving the resizing signal D10 is shown as region S2 (solid line). Both regions S1 and S2 are assumed to have the target position P2 at their center. For example, the image resizing unit 71 determines that the first condition is met if, in the position information D2, the target object P1 is within region S1 (within a predetermined range centered on the target position P2). The image resizing unit 71 then generates a resizing signal D10 to reduce the size of the image data D1 from region S2 to the range of region S1, and outputs it to the imaging unit 1. The imaging unit 1 reduces the size of the image data D1 to be output according to the resizing signal D10. That is, the imaging unit 1 outputs a portion of the captured image as image data D1 according to the size of the image data D1 changed by the image resizing unit 71. As a result, when the target object P1 approaches the target position P2, the size of the image data D1 output from the imaging unit 1 decreases, shortening the transfer time of the image data D1 and increasing the image processing speed of the image processing unit 4 (position information generation unit 41). This allows the movement speed of the target object to be increased, thus shortening the movement time of the target object.

[0041] In this embodiment, for the sake of explanation, the target position P2 is assumed to be located at the center of Figure 3, but this is not the only possible configuration. For example, if the positional relationship between the target object P1 and the target position P2 is predetermined, the position of the target position P2 may be determined accordingly. For instance, if it is predetermined that the target position P2 is to the right of the target object P1, the target position P2 may be placed on the right side of Figure 3.

[0042] As shown in Figure 1, the control gain changing unit 72 changes the control gain (control parameter) in the first control unit 6 in response to the size change signal D10. Specifically, when the size of the image data D1 is reduced by the size change signal D10, the control gain changing unit 72 generates a gain change signal D11. When the first control unit 6 receives the gain change signal D11, it increases the control gain. When the size change signal D10 is output, it can be said that the target object P1 and the target position P2 are in close proximity, so by increasing the control gain (feedback gain) in the first control unit 6, the target object P1 can be moved to the target position P2 more quickly.

[0043] The display unit 73 is, for example, a display device such as a screen. The display unit 73 displays an image to the user of the positioning device in response to instructions from the second control unit 7.

[0044] The control unit 74 is, for example, an input device such as a mouse or keyboard. The control unit 74 receives input from the user.

[0045] The setting unit 75 receives the setting of the first condition. The setting unit 75 displays an image for setting the first condition (such as the setting screen described below) on the display unit 73 and accepts the setting of the first condition via the operation unit 74.

[0046] Figure 4 is an image showing an example of the setting screen for the first condition according to the first embodiment. As shown in Figure 4, the setting screen displays the first screen Sc1 for setting the first condition in the center. The first screen Sc1 displays the target object P1, the target position P2, areas S3 and S4, and the mouse pointer P3. Area S3 is the area where the image resizing unit 71 determines that the first condition is met when the target object P1 and the target position P2 are within area S3. Area S4 is the area where the image resizing unit 71 changes the size of the image data D1 when it determines that the first condition is met (corresponding to area S2 in Figure 3). The user can move the mouse pointer P3 within the setting screen by operating the operation unit 74, for example. Then, within the first screen Sc1, the user can change the size of areas S3 and S4 as appropriate by operating (dragging, etc.) the areas S3 and S4. In other words, the setting unit 75 allows the user to set the first condition.

[0047] Furthermore, the settings screen in Figure 4 displays a second screen, Sc2, at the bottom, which shows the transfer time of image data D1. The transfer time of image data D1 is the time it takes for the image data D1 to be transferred from the imaging unit 1 to the image processing unit 4 (position information generation unit 41). In the example in Figure 4, the increase / decrease ratio (e.g., 1 / 4) of the transfer time of image data D1 is displayed depending on the set region S4. The transfer time of image data D1 varies depending on the size of region S4. Specifically, the transfer time of image data D1 becomes longer when the size of region S4 is large, and shorter when the size of region S4 is small. As a result, the user can visually observe the improvement in the delay time in the positioning device by changing the size of region S4, and thus confirm that the image data transfer time in this positioning device is shortened. In addition, since the control gain (control parameter) is set according to the transfer time of image data D1 and the generation time of position information D2, the movement time of the target object can also be confirmed in practice.

[0048] Furthermore, in the settings screen shown in Figure 4, the fifth screen, Sc5, is displayed between the first screen, Sc1, and the second screen, Sc2. When either area S3 or S4 is selected using the mouse pointer P3, the coordinates of the top right and bottom left corners of the selected area are displayed on the fifth screen, Sc5.

[0049] (Second Embodiment) Figure 5 is a schematic diagram showing the configuration of the positioning device according to the second embodiment. Compared to Figure 1, Figure 5 shows that the moving mechanism 1 is further provided with a drive unit 14, and the first control unit 6 is further provided with a position control unit 61c and a speed control unit 62c. In addition, two imaging units 2 are provided.

[0050] The drive unit 14 is located on the stage 11. The drive unit 14 rotates the stage 11 in the XY plane. That is, the target object P placed on the stage 11 moves in the X and Y directions on the stage 11 and rotates in the XY plane as a result of being driven by the drive units 12 to 14.

[0051] Although a detailed explanation is omitted, the position control unit 61c and the speed control unit 62c are configured similarly to the position control unit 61a and the speed control unit 62a, respectively. In the positioning device of the second embodiment, a feedback control system is configured in which the displacement of the drive unit 14 in the rotational direction (drive direction) and the displacement of the target object P1 in the rotational direction are fed back to the first control unit 6. Therefore, the control system of the positioning device can be stabilized even in the rotational direction.

[0052] The drive unit 14 may also move the stage 11 in the Z direction. As a result, the target object P1 placed on the stage 11 moves on the stage 11 in the X, Y, and Z directions as the drive units 12 to 14 are driven.

[0053] In the second embodiment, two target objects P1 are provided, along with two imaging units 2. The two imaging units 2 each image the corresponding target object P1. Note that in Figure 5, the target position P2 is omitted from the illustration.

[0054] For example, when positioning is performed using one imaging unit 2 based on one target object P1, it is difficult to detect the position of the target object P1 with high accuracy in relation to the rotational direction in the XY plane. Therefore, it is conceivable to use two target objects to detect the position of the target object P1 with high accuracy. In this case, it becomes possible to accurately detect the position of the target object P1 with respect to the rotational direction from the positions of the two target objects P1. Furthermore, in this case, the further apart the two target objects P1 are placed, the higher the accuracy of position detection becomes. However, when imaging two target objects P1 with one imaging unit 2, the further apart the two target objects P1 are placed, the more pixels the imaging unit 2 needs to have, and the more pixels that image positions where no target object P1 exists, the more unnecessary pixels there are, resulting in an increase in the cost of the imaging unit 2. Therefore, by providing two imaging units 2 in the positioning device, and having the two imaging units 2 each image the corresponding target object P1, it is possible to reduce unnecessary pixels when imaging the two target objects P1. This allows for high-precision detection of the position (especially the rotational direction) of the target object P1 while keeping the cost of the imaging units 2 down.

[0055] Here, the setting unit 75 may set different first conditions for each of the two imaging units 2.

[0056] Figure 6 is an image showing an example of the setting screen for the first condition according to the second embodiment. As shown in Figure 6, the setting screen displays a third screen Sc3 in the upper left for setting the first condition of the left imaging unit 2 in Figure 5. The setting screen also displays a fourth screen Sc4 in the upper right for setting the first condition of the right imaging unit 2 in Figure 5. The third screen Sc3 and the fourth screen Sc4 display the target object P1, the target position P2, and the regions S3 and S4, respectively, similar to the first screen Sc1, and the size of each region S3 and S4 can be changed using the mouse pointer P3. The setting screen in Figure 6 also displays a second screen Sc2 at the bottom, which shows the transfer time of the image data D1. The transfer time of this image data D1 changes according to the size of the larger region S4 among the regions S4 in the third screen Sc3 and the fourth screen Sc4.

[0057] Note that the settings screen in Figure 6 displays the fifth screen, Sc5, similar to the settings screen in Figure 4. When either area S3 or S4 is selected using the mouse pointer P3, the coordinates of the upper right and lower left corners of the selected area are displayed on the fifth screen, Sc5.

[0058] (Other embodiments) As described above, embodiments have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these embodiments and can be applied to embodiments that are modified, replaced, added, or omitted as appropriate. Furthermore, it is possible to create new embodiments by combining the components described in the above embodiments.

[0059] In each of the above embodiments, the image processing unit 4, the conversion unit 5, the first control unit 6, and the second control unit 7 may be composed of one computer or multiple computers.

[0060] Furthermore, in each of the above embodiments, the imaging unit 1 may reduce the size of the captured image according to the positional relationship between the target object P1 and the target position P2, and output the reduced image as image data D1. For example, the image size change unit 71 generates a size change signal D10 to reduce the size of the captured image when it determines that the target object P1 is not within the region S1 (within a predetermined range centered on the target position P2) in the position information D2, i.e., when the first condition is not met. As a result, when the target object P1 is far from the target position P2, the size of the image data D1 output from the imaging unit 1 becomes smaller, and the image processing speed of the image processing unit 4 (position information generation unit 41) increases. This makes it possible to shorten the movement time of the target object.

[0061] Furthermore, although the above embodiments show that the regions S3 and S4 displayed on the settings screen are both rectangles, regions Sc3 and Sc4 may have shapes other than rectangles, such as circles or ellipses. Also, regions Sc3 and Sc4 do not have to be closed intervals like rectangles; they can be any shape as long as a region that satisfies the first condition can be specified. For example, the first screen Sc1 could be divided by a straight line, and the region could be one of the regions of the first screen Sc1 divided by that line.

[0062] Furthermore, in each of the above embodiments, multiple areas S3 and S4 displayed on the setting screen may be provided so that multiple first conditions can be set in stages.

[0063] Furthermore, in each of the above embodiments, the transfer time of the image data D1 displayed on the second screen Sc2 in the settings screen may be a specific transfer time (e.g., 10 μs) rather than an increase / decrease ratio of the transfer time (e.g., 1 / 4). Also, instead of the transfer time of the image data D1, the second screen Sc2 may display the time from when the imaging unit 1 captures an image until the position information D2 (image recognition result) from the position information generation unit 41 is output (image recognition delay time) for setting the control gain (control parameter).

[0064] Furthermore, in each of the above embodiments, the transfer time of the image data D1 displayed on the second screen Sc2 may be set on the settings screen. In this case, the size of the area S4 displayed on the settings screen will be set according to the transfer time of the image data D1.

[0065] Furthermore, in each of the above embodiments, the sizes of regions S3 and S4 displayed on the settings screen may be set based on the coordinates on the settings screen. For example, the coordinates of the upper left and lower right corners of region S4 (or region S3) may be set using the fifth screen Sc5 at the bottom of Figures 4 and 6.

[0066] Furthermore, in each of the above embodiments, in the first screen Sc1, etc., the region S3 in which the first condition is considered to be met and the region S4 in which the size of the image data D1 is changed can be set separately, but regions S3 and S4 may be a single region. [Industrial applicability]

[0067] The positioning device of this disclosure is useful because it can shorten the travel time of the target object. [Explanation of Symbols]

[0068] 1 Moving mechanism 11 stages 12-14 Drive unit 2 Imaging Unit 3 light source 4 Image Processing Unit 41 Location information generation section 5. Conversion section 6. First Control Unit 7. Second Control Unit 71 Image resizing section 72 Control Gain Change Section (Control Parameter Change Section) 75 Settings Section P1 target P2 target position D1 Image Data

Claims

1. A moving mechanism for moving the target object, An imaging unit for photographing the aforementioned target object, An image processing unit outputs positional information of the target object based on the image data captured by the imaging unit, A control unit controls the movement mechanism to move the target object to the target position based on the position information, A positioning device comprising an image resizing unit that changes the size of the image data output from the imaging unit according to the positional relationship between the target object and the target position.

2. The positioning device according to claim 1, wherein the imaging unit outputs a portion of the image as image data according to the size of the image data changed by the image size changing unit.

3. The positioning device according to claim 1, wherein the imaging unit reduces the size of the image data that has been changed by the image size changing unit, and outputs the reduced image as the image data.

4. The positioning device according to claim 1, further comprising a control parameter changing unit that changes control parameters for controlling the movement mechanism in the control unit according to the size of the image data changed by the image size changing unit.

5. The positioning device according to claim 1, further comprising a setting unit for setting conditions when the image resizing unit changes the size of the image data.

Images