JP2008205051A - Head position control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for accurately controlling a head to a target point regardless of the moving direction of the head toward the target point before reaching it. <P>SOLUTION: A database is obtained by measuring an error quantity between an instructed destination point of a head 102 that is instructed to an XY drive part from a control part and an actual point that the head 102 reaches in each moving direction of the head 102. Using the database, the instructed destination point of the head 102 that is instructed to the XY drive part from the control part is corrected, thus improving precision in reaching a target point of the head 102. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a head position control method for a component mounting apparatus for mounting an electronic component or the like on an electronic circuit board. More specifically, the head position is controlled to a target point with high accuracy regardless of the head moving direction approaching the target point. On how to do.

  FIG. 1 is a plan view showing a schematic configuration of an example of a current component mounting apparatus.

  The component mounting apparatus 100 supplies a head unit 102 to which a nozzle that adsorbs components can be mounted, an XY drive unit 104 that can move the head unit 102 in a plane direction (XY direction), and a component 105 (see FIG. 4). Component supply section 106, board transport section 108 that carries in and out the electronic circuit board 108A, and nozzle replacement section 110, and their positions and axis operations are coordinates with reference mark 112 as a reference point. It is determined by the system.

  FIG. 2 is a perspective view showing the head unit 102. The head unit 102 includes a camera unit 114 and a component mounting unit 116. The head unit 102 is connected and fixed to the XY driving unit 104 and can be moved in the plane direction (XY direction) by the XY driving unit 104.

  The camera unit 114 captures the reference mark 112 to set the coordinate system, images the electronic circuit board 108A and the component supply unit 106, confirms the mounting position and the suction position, performs teaching, and performs mounting and suction. For positioning.

  FIG. 3 is a diagram showing an outline of the component mounting unit 116.

  The component mounting unit 116 includes a nozzle 118 that can move in the vertical direction. The nozzle 118 can rotate about its axis. The component mounting unit 116 sucks the component by the nozzle 118 and mounts the component 105 on the electronic circuit board 108A.

  One end of the shaft 120 is connected to a vacuum generator (not shown), and the nozzle 118 is attached to the other end. The shaft 120 can be moved in the vertical direction by the Z-axis motor 122, and the shaft 120 can be rotated around the axis by the θ-axis rotation motor 124. In addition, the component mounting unit 116 is provided with a component recognition device 126 that detects the position of the component 105 sucked by the nozzle 118 by emitting laser light in the horizontal direction.

  The operation of the component mounting apparatus 100 will be described. First, the coordinate system is set by recognizing the reference mark 112 by the camera unit 114 included in the head unit 102. The head unit 102 is positioned on the component supply unit 106 by the XY driving unit 104 using the set coordinate system. Thereafter, the shaft 120 of the component mounting portion 116 is lowered and the lower end of the nozzle 118 is lowered to a predetermined position. Then, the vacuum generator is operated and the component 105 is sucked by the nozzle 118.

  The position of the component sucked by the nozzle 118 is measured by the component recognition device 126, and the control unit 128 (see FIG. 6) drives the θ-axis rotation motor 124 based on the result, and the component 105 sucked by the nozzle 118. Correct the posture.

  Thereafter, the XY driving unit 104 positions the head unit 102 on the electronic circuit board 108A. Then, after the shaft 120 of the component mounting portion 116 is lowered by the Z-axis motor 122 and the lower end of the nozzle 118 is lowered to a predetermined position, the vacuum generator is stopped and the suction is released to release the component 105 from the nozzle 118. Then, the component 105 is mounted on the electronic circuit board 108A.

  However, as shown in FIG. 4, even when the component 105 is mounted by moving the head unit 102 to the same target point 152 on the electronic circuit board 108 </ b> A by the XY driving unit 104, the head unit toward the target point 152. When the moving direction of 102 is different, the mounting points 154 and 156 of the component 105 do not coincide with each other and may be slightly different, so that the moving point 102 is not necessarily accurately moved to the target point 152.

  Normally, when a new coordinate system is set, the camera unit 114 mounted on the head unit 102 is moved onto the reference mark 112 that determines the reference of the coordinate system, and the camera unit 114 is made to recognize the reference mark 112. Based on this recognition result, a new coordinate system is set. However, the position of the camera unit 114 is slightly different due to the difference in the moving direction on the reference mark 112. As a result, the position of the recognized reference mark 112 is also slightly different. In contrast, the newly set coordinate system was slightly different.

  The above-mentioned phenomenon in which the position where the head unit 102 actually reaches differs due to the difference in the moving direction of the head unit 102 to the target point is due to the backlash of the driving mechanism of the XY driving unit 104, the load applied to the driving mechanism, etc. Is considered to be the cause.

  Therefore, in order to deal with the above-described phenomenon, an invention has been proposed in which the moving direction of the head unit 102 is set to a fixed direction after the head unit 102 approaches within a predetermined distance from the target point. . Although the present invention is a prior application (Japanese Patent Application No. 2006-108160), it is not disclosed at the present time and is not publicly known.

  However, in the present invention, since the moving direction needs to be a certain direction after the head unit 102 approaches within a predetermined distance from the target point, the target point 162, 164 is reached as shown in FIG. The shortest route cannot be moved, and it is necessary to take the travel routes 162A and 164A that have been turned around, resulting in a problem that the moving distance becomes long and the time until moving to the target point becomes long.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a method for accurately controlling the head unit to the target point regardless of the moving direction until the head unit reaches the target point. And

  As a result of diligent research to solve the above problems, the present inventor has actually found the movement command point of the head unit 102 that the control unit 128 commands the XY drive unit 104 for each movement direction of the head unit 102 to the target point. By measuring the amount of error from the point of arrival and adjusting the movement command point to be commanded to the XY drive unit 104 in consideration of this amount of error for each moving direction, until the head unit 102 reaches the target point The present inventors have found that the movement of the head unit 102 to the actual target point can be controlled with high accuracy regardless of the moving direction of the head.

  That is, the head position control method according to the present invention includes a camera unit capable of recognizing an object, a head having a component mounting unit for mounting a component on a substrate, an XY driving unit for driving the head in a plane direction, and the XY A head position control method in a component mounting apparatus including a control unit that controls a position of the head in a planar direction via a drive unit, wherein the control unit commands the XY drive unit to move the head The head movement command that the control unit commands the XY drive unit using a database obtained by measuring the error amount between the point and the point where the head actually reaches for each movement direction of the head The point is corrected to improve the accuracy of reaching the moving target point of the head.

  The error amount in the moving direction that is not in the database may be calculated using the error amount in the moving direction that is in the database.

  According to the head position control method of the present invention, the error amount between the head movement command point commanded by the control unit to the XY drive unit and the point where the head actually arrives is measured for each head movement direction. The movement command point of the head to be commanded is corrected using the database, so that the movement of the head unit to the actual target point can be controlled with high accuracy regardless of the moving direction until the head unit reaches the target point. .

  Therefore, it is possible to minimize the movement path of the head part while controlling the movement of the head part to the actual target point with high accuracy, and to shorten the movement time of the head part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 6 is a block diagram when carrying out an example of an embodiment of a head position control method according to the present invention.

  The control unit 128 includes a CPU 128A and a memory 128B. Data relating to the component 105 and the electronic circuit board 108 </ b> A can be input to the control unit 128 by the data input unit 132, and the control unit 128 can exchange data with the storage device 134.

  The control unit 128 controls the XY driving unit 104 by the X-axis motor 136 having the encoder 136A and the Y-axis motor 138 having the encoder 138A, and the head unit 102 (camera unit 114 and component mounting unit 116) is planar. Move in the direction (XY direction). Further, the position of the nozzle 118 in the vertical direction (Z direction) is controlled by the Z-axis motor 122 incorporating the encoder 122A, and the position of the nozzle 118 in the rotational direction around the axis is controlled by the θ-axis motor 124 incorporating the encoder 124A. Control.

  Image data picked up by the camera unit 114 is sent to the image processing device 140 for data processing. The image processing apparatus 140 includes an A / D converter 140A, a CPU 140B, and a memory 140C. The image data can be displayed on the display device 142.

  Next, the procedure for controlling the movement of the head unit 102 will be described with reference to the flowcharts of FIGS.

  FIG. 7 is a flowchart showing a procedure for controlling the head position. First, for each movement direction of the head unit 102, an error amount between the movement command point of the head unit 102 that the control unit 128 commands the XY drive unit 104 and the point where the head unit 102 actually reaches is acquired, and the storage device A database for the error amount is constructed (step S1). Next, the current position of the head unit 102 is acquired from the encoder 136A and the encoder 138A (step S2), and the movement target point of the head unit 102 is input to the control unit 128 by the data input unit 132 (step S3). The movement angle to the point is calculated (step S4).

  The error amount corresponding to the movement angle is acquired from the database constructed in step S1 (step S5), and the error amount is added to or subtracted from the coordinates of the movement target point (step S6). The movement command point of the head unit 102 to be commanded is calculated (step S7). Then, the control unit 128 issues a command to move the head unit 102 to the movement command point to the XY driving unit 104 to move the head unit 102 (step S8).

  Even if the control unit 128 issues a command to move the head unit 102 to the movement command point, the head unit 102 reaches the movement command point because there is actually an error amount corresponding to the moving direction. Without reaching the target location.

  FIG. 8 is a flowchart showing in detail a procedure for constructing a database for the error amount in step S1.

  First, the counter is set to 0 (Cnt = 0) (step S11). Next, it is set how many times the movement angle of the head unit 102 to the reference mark 112 is shaken to construct the database (step S12). Here, the movement angle is assumed to be changed every A °. The number N of times the head unit 102 recognizes the reference mark 112 is obtained from N = 360 / A (step S13). As a result, the operation in which the head unit 102 recognizes the reference mark 112 is performed from all directions from 0 ° to 360 ° as shown in FIG. FIG. 9 shows a case where A = 45, and the arrow in FIG. 9 indicates the moving direction of the head unit 102. The operation in which the head unit 102 recognizes the reference mark 112 is performed from the direction in which the angle formed with the X direction is 0 ° in FIG.

  After moving the head unit 102 to a position immediately above the reference mark 112 so that the image center of the camera unit 114 of the head unit 102 is located at the center of the reference mark 112 (step S14), a predetermined angular direction (A × It is moved a certain distance in the direction of Cnt degree) (step S15). Thereafter, the control unit 128 issues a command to the XY drive unit 104 to move the head unit 102 to position the head unit 102 at a position directly above the reference mark 112 (step S16). At the point after the movement, the reference mark 112 is recognized by the camera unit 114, and an error amount between the image center of the camera unit 114 and the center of the reference mark 112 is acquired and stored in the storage device 134 (step S17). Then, 1 is added to the count number (Cnt ++) (step S18), and it is determined whether the count number has reached the number of times of recognition N. If it has reached, the acquisition of data is terminated. If not, the process goes to step S14. Returning and data acquisition is continued (step S19).

  As described above, the moving direction of the head unit 102 to the reference mark 112 is shaken without deviation in the range of 0 ° to 360 °, and the error amount is acquired for the angle in the range of 0 ° to 360 °. Build a database about quantity. A part of an example of the constructed database is shown in FIG.

  Further, an average value is calculated for the error amount in each movement direction obtained by shaking the movement direction of the head unit 102 to the reference mark 112 in a range of 0 ° to 360 °, and this average value is calculated by the control unit. 128 is added to or subtracted from the coordinates initially recognized as the reference mark position to correct the reference mark position, and a coordinate system is formed based on the corrected reference mark position.

  Once the database for the error amount for each movement direction is obtained, the movement command point is calculated by adding or subtracting the error amount in the movement direction when moving to the movement target point to the coordinates of the movement target point. When the control unit 128 instructs the XY driving unit 104 to move to the position, the head unit 102 is controlled to the movement target point with high accuracy.

  In FIG. 11, the current position of the head unit 102 is (100, 0), the movement target point is (0, 0), and the movement command point when the movement direction is 0 ° is (−0.05, It is a figure which shows typically the case where it is 0). The control unit 128 commands the XY drive unit 104 to move the head unit 102 to the movement command point (−0.05, 0), so that the head unit 102 can accurately move to the movement target point (0, 0). Be controlled.

  As described above, the moving direction of the head unit 102 to the reference mark 112 is shaken without deviation in the range of 0 ° to 360 °, and the error amount is acquired for the angle in the range of 0 ° to 360 °, and the error is obtained. It is desirable to construct a database about the quantity, move the head unit 102 using this database, and control the position of the head unit 102, but the first quadrant (movement angle 0 ° to 90 °) and the third quadrant It is also possible to construct only a database for error amounts in the second quadrant (movement angle 90 ° to 180 °) and the fourth quadrant (movement angle 270 ° to 360 °) (movement angle 180 ° to 270 °).

For example, as shown in FIG. 12, when the moving direction is 45 °, the error amount is (A _x1 , B _y1 ), and when the moving direction is 225 °, the error amount is (A _x3 , B _y3 ). Then, the predicted value of the error amount when the moving direction is 0 ° is (A _x1 / cos 45 °, 0), and the predicted value of the error amount when the moving direction is 90 ° is (0, By ₁ / sin 45 °). prediction value of the error amount in the case the moving direction of 180 ° is _{(a x3 / cos45 °, 0} ), the predicted value of the error amount in the case the moving direction of 270 ° becomes _{(0, B y3 / sin45 °} ).

Therefore, for example, the predicted value of the error amount when the moving direction is 120 ° is ((A _x3 / cos 45 °) × cos 60 °, (B _y1 / sin 45 °) × sin 60 °), and (0.71A _x3 , 1 .22B _y1 ). Further, for example, the predicted value of the error amount when the moving direction is 330 ° is ((A _x1 / cos 45 °) × cos 30 °, (B _y1 / sin 45 °) × sin 30 °), and is (1.22A _x3 , 0 .71B _y1 ).

  Thus, from the error amount in the first quadrant (movement angle 0 ° to 90 °) and the third quadrant (movement angle 180 ° to 270 °), the second quadrant (movement angle 90 ° to 180 °) and the fourth quadrant. It is possible to predict the error amount at (movement angle 270 ° to 360 °).

  In the embodiment described above, the accuracy of the moving position of the head unit 102 is improved by using the error amount database for the moving direction. However, the error amount is further varied by changing the moving speed and moving distance for each moving direction. By using a database obtained by measuring the above, it is possible to control the movement position with higher accuracy.

The top view which shows schematic structure of an example of the present component mounting apparatus The perspective view which shows the head part of the said component mounting apparatus The figure which shows the outline | summary of the component mounting part of the said head part. Schematic diagram when mounting the parts by moving the head from the different movement directions to the same target point The schematic diagram which shows the problem of the technique which concerns on a prior application (Japanese Patent Application No. 2006-108160) A block diagram when carrying out an example of an embodiment of a head position control method according to the present invention Flow chart showing the procedure for controlling the head position Flow chart showing in detail the procedure for constructing the database for the error amount Movement direction of the head when the head recognizes the reference mark A diagram showing a part of an example of a built database When the current position of the head part is (100, 0), the movement target point is (0, 0), and the movement command point when the movement direction is 0 ° is (−0.05, 0) Figure schematically showing The figure which shows typically the error amount when the moving direction of a head part is 45 degrees, and the error amount when a moving direction is 225 degrees

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Component mounting apparatus 102 ... Head part 104 ... XY drive part 105 ... Component 106 ... Component supply part 108 ... Substrate conveyance part 110 ... Nozzle replacement part 112 ... Reference mark 114 ... Camera part 116 ... Component mounting part 118 ... Nozzle 120 ... Shaft 122 ... Z-axis motor 124 ... θ-axis motor 126 ... Part recognition device 128 ... Control unit 128A ... CPU
128B ... Memory 132 ... Data input means 134 ... Storage device 136 ... X-axis motor 138 ... Y-axis motor 122A, 124A, 136A, 138A ... Encoder 140 ... Image processing device 140A ... A / D converter 140B ... CPU
140C ... Memory 142 ... Display device 152 ... Target point 154, 156 ... Mounting point 162, 164 ... Target point 162A, 164A ... Movement route

Claims (2)

A head having a camera unit capable of recognizing an object and a component mounting unit for mounting the component on the substrate, an XY driving unit for driving the head in a planar direction, and a position in the planar direction of the head via the XY driving unit A head position control method in a component mounting apparatus provided with a control unit for controlling
Using a database obtained by measuring the error amount between the movement command point of the head commanded by the control unit to the XY drive unit and the point where the head actually reaches for each moving direction of the head, A head position control method, wherein the head movement command point commanded by the control unit to the XY drive unit is corrected to improve the accuracy of reaching the head movement target point.   An error amount for a moving direction not in the database is calculated using an error amount for the moving direction in the database, and the movement command point commanded by the control unit to the head is corrected using the calculated error amount. The head position control method according to claim 1, wherein the accuracy of reaching the moving target point of the head is improved.

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