JP2010082782A - Suction device and suction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suction device capable of automatically detecting an abrasion or a displacement arising on a suction pad. <P>SOLUTION: The suction device 100 has a control part 40 having such a function for controlling that when a suction sensor 30 measures a suction force F1 at a reference position L<SB>0</SB>of the suction pad 10 and a deciding part 42 decides that the measured suction force F1 is smaller than a threshold value TH, a driving part 20 displaces the suction pad 10 by a prescribed displacement amount in an elevating or lowering direction or an intersecting direction, and when the suction sensor 30 measures a suction force F2 of the suction pad 10 at a displaced position (displaced position L<SB>D</SB>) and the deciding part 42 decides that the suction force F2 is larger than the threshold value TH, a displacement amount ΔL is obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an adsorption device and an adsorption method.

A robot arm with a suction pad attached to the tip is widely used for transporting workpieces. The suction pad is a member that obtains a suction force with respect to the surface to be suctioned of the workpiece by vacuum suction of the inside thereof.
In order to accurately convey the work to a predetermined position, it is necessary to accurately align the work and the suction pad.
Here, various inventions have been proposed regarding techniques for aligning the workpiece and the suction pad. For example, Patent Document 1 described below describes a suction device in which a hole is formed in the suction pad so that the horizontal displacement between the workpiece and the suction pad can be visually confirmed. Patent Document 2 below describes a suction device that automatically corrects the suction position of the suction pad in the horizontal direction using an optical sensor and a center display of a workpiece.

Japanese Utility Model Publication No. 6-75629 JP-A-9-225877

However, the suction pad is worn or displaced from the reference position due to long-term use. When the suction pad is worn or misaligned, the suction force with respect to the workpiece is reduced, and the occurrence of a suction error becomes a problem. When a suction mistake by the suction pad occurs, an operation loss due to post-maintenance occurs, resulting in an increase in cost.
On the other hand, the inventions described in Patent Documents 1 and 2 detect the horizontal displacement between the suction pad and the work by optical means, and require a special shape or marking on the work. Poor sex.

The suction device of the present invention includes a suction pad for vacuum-sucking a workpiece,
Driving means for driving the suction pad in the up-and-down direction with respect to the workpiece, or in the crossing direction with respect to the up-and-down direction;
Measuring means for measuring the suction force of the suction pad;
Determination means for determining the magnitude of the measured adsorption force and a predetermined threshold;
When the measuring means measures the suction force at the reference position of the suction pad and the determination means determines that the measured suction force is smaller than the threshold value, the driving means raises and lowers the suction pad. The predetermined displacement amount is displaced once or a plurality of times in the direction or the crossing direction, and the measuring unit measures the suction force of the suction pad at the displaced position, and the determination unit determines that the suction force is greater than the threshold value. Control means having a function of acquiring the amount of displacement when determined by;
Is provided.

Further, the suction method of the present invention includes a first measurement step for measuring the suction force of a suction pad for vacuum-sucking a workpiece at a reference position,
A first displacement step of displacing the suction pad by a predetermined displacement amount in a lifting direction with respect to the workpiece or in a crossing direction with respect to the lifting direction when the measured suction force is smaller than a predetermined threshold;
A second measurement step of measuring the suction force of the suction pad at the displaced position;
A displacement information acquisition step of acquiring the amount of displacement when the suction force is greater than the threshold;
including.

  In the above invention, when it is determined that the suction force of the suction pad is smaller than a predetermined threshold value, the suction force is measured again by displacing the suction pad in the ascending / descending direction or the crossing direction with respect to the workpiece. The position of the suction pad from which is obtained is obtained. Thereby, when the suction force exceeds the threshold value due to the displacement in the up-and-down direction, it is detected that the suction pad is worn or that the position of the suction pad has shifted in the up-and-down direction. Further, when the suction force is improved by the displacement in the intersecting direction, it is detected that the suction pad is displaced in the direction.

In the above invention, the suction pad vacuum-sucking the work means that the work is sucked by sucking the inside of the suction pad to a negative pressure rather than the installation atmosphere of the suction device.
Moreover, the raising / lowering direction with respect to a workpiece | work means the up-down of the surface orthogonal direction with respect to the to-be-sucked surface of the workpiece | work attracted | sucked by a suction pad, and does not necessarily mean the up-down of a gravitational direction.

  Further, the various components of the present invention do not have to be individually independent, that a plurality of components are formed as one member, and one component is formed of a plurality of members. It may be that a certain component is a part of another component, a part of a certain component overlaps a part of another component, and the like.

  Moreover, in describing the adsorption method according to the present invention, a plurality of steps may be described in order, but the order of description does not necessarily limit the order in which the steps are executed, unless explicitly stated. In addition, a plurality of processes are not limited to being executed at different timings unless explicitly stated, other processes may occur during execution of a certain process, execution timing of a certain process, and other timing. It may be that part or all of the process execution timing overlaps.

  ADVANTAGE OF THE INVENTION According to this invention, the general purpose adsorption | suction apparatus and adsorption | suction method which can detect the abrasion and position shift which arose to the adsorption | suction pad, and can prevent that the adsorption | suction mistake by the fall of the adsorption | suction power with respect to a workpiece | work are produced are provided. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

<Adsorption device>
FIG. 1 is a schematic diagram illustrating an example of an adsorption device 100 according to the first embodiment of the present invention. In the figure, a one-dot chain line indicates a signal line.

First, the outline | summary of the adsorption | suction apparatus 100 of this embodiment is demonstrated.
The suction device 100 according to the present embodiment includes a suction pad 10 that vacuum-sucks the work 120, and a lifting direction of the suction pad 10 with respect to the work 120 (up and down direction in FIG. 1) or a crossing direction with respect to the lifting direction (left and right direction in FIG. A driving unit 20 that drives in the front-rear direction, a measurement unit that measures the suction force of the suction pad 10 (suction sensor 30), and a determination unit that determines the magnitude of the measured suction force and a predetermined threshold TH. And.
The suction device 100, when the suction force F1 suction sensor 30 measures the measured attractive force F1 is determined the determination unit 42 and the threshold value TH is smaller than the reference position L ₀ of the suction pad 10 is driven The unit 20 displaces the suction pad 10 a predetermined displacement amount in the up-down direction or the crossing direction once or a plurality of times, and the suction sensor 30 measures the suction force F2 of the suction pad 10 at the displaced position (displacement position L _D ). In addition, it further includes a control unit 40 having a function of acquiring the displacement amount ΔL when the determination unit 42 determines that the suction force F2 is greater than the threshold value TH.

Next, the adsorption device 100 of this embodiment will be described in detail.
The suction device 100 is a mechanism used by being incorporated in the arm unit 26 of a transfer robot (not shown).
The workpiece 120 can be a variety of products including semiconductor devices, parts, or members.

In the present embodiment, the workpiece 120 is placed on the upper surface of the feed base 130 and continuously fed to the suction device 100. The suction device 100 sucks and holds the workpieces 120 individually and transports them to a predetermined position. On the upper surface of the work 120, a flat attracted surface 122 over a predetermined area is formed. The suction target surface 122 includes the suction surface 11 of the suction pad 10 and includes a suction permissible region around the periphery of the suction pad 10 that allows positional variation of a predetermined width.
On the other hand, the suction pad 10 is provided at the lower end of the suction device 100 of the present embodiment so as to open in the −Z direction.

As shown in FIG. 1, the upper surface of the feed base 130 is the XY plane, and the direction perpendicular thereto is the Z direction. Hereinafter, for convenience, the XY direction is referred to as a horizontal direction, and the Z direction is referred to as an ascending / descending direction.
The origin O is the zero point position (0, 0, 0) of the suction pad 10 when the suction holding operation for the workpiece 120 is started. More specifically, the origin O is the lower end surface (suction surface 11) of the suction pad 10. The center position.
The work 120 is set at a position (work position L _W ) and is sucked and held by the suction pad 10. The relative positions of the origin O and the work position _{L W (δX, δY, δZ} ) are known.
The reference position L ₀ is a position where the suction force F1 of the suction pad 10 is measured in order to detect wear or displacement of the suction pad 10, and the relative positions (δX ₀ , δY ₀ , δZ ₀ ) from the origin O are Known. Here, the reference position L ₀ is may be coincident with the origin O or a work position L _W, or may be provided in these and differences are located. In this embodiment, the relative positional relationship between the origin O and the reference position L ₀ is known.

A controller 40 is connected via a signal line to the drive unit 20 that drives the suction pad 10 to each axis in the X, Y, and Z directions. The control unit 40 is a computer that controls the entire adsorption device 100, and includes a storage unit 60 such as a semiconductor memory. Specifically, the control unit 40 does not have sufficient data processing of the measurement signal SG output from the suction sensor 30, control of the driving direction and driving amount of the suction pad 10 by the driving unit 20, and suction force of the suction pad 10. When the determination unit 42 determines that there is, output control of the notification unit 50 is performed.
The determination unit 42 is a computer that accesses the storage unit 60 in which the threshold value TH is stored and determines the magnitude of the suction force of the suction pad 10 and the threshold value TH.
In the case of this embodiment, the control unit 40 and the determination unit 42 are realized by a common computer. However, the present invention is not limited to this, and the control unit 40 and the determination unit 42 may be configured by different computers.

The storage unit 60 stores position information indicating the origin O of the suction pad 10 as X, Y, and Z direction components, and the drive unit 20 can be driven to set the suction pad 10 to the zero point position. it can.
The storage unit 60, position information indicating the reference position L ₀ and work position L _W is, as a relative position from the origin O, X, Y, are respectively stored for each Z-direction component.
The suction device 100, a suction pad 10 which is set to the origin O to the workpiece position _{L W (δX, δY, δZ} ) by simply moving parallel to properly suction the workpiece 120 at the suction pads 10 it can.

That is, the suction device 100 according to the present embodiment stores the teaching value VT indicating the position of the workpiece 120 (work position L _W ) in the storage unit 60. The teaching value VT is data indicating a relative position from a known point to the attracted surface 122 of the workpiece 120. As the known point, the zero point position or the reference position L ₀ of the suction pad 10 can be exemplified. In the present embodiment, the teaching value VT is stored in the storage unit 60 as the relative position (δX, δY, δZ) between the origin O and the workpiece 120.

In addition, the suction device 100 of the present embodiment includes a position confirmation jig 110 that has a suction surface 112 larger than the suction pad 10 and is fixed to a known relative position with respect to the workpiece 120. . The attracted surface 112 of the localization fixture 110 is disposed in the reference position L ₀ of the suction pad 10 in the absence of wear and positional deviation. Further, the attracted surface 112 has a shape that includes the attracting surface 11 of the attracting pad 10, and has a shape that is the same as or smaller than the attracting allowable area of the workpiece 120.

In the case of this embodiment, the relative position between the origin O and the workpiece 120 (work position L _W ) and the relative position between the origin O and the reference position L ₀ are stored in the storage unit 60, so the workpiece position L _W and the reference position L ₀ is at a known relative position.
Then, the suction pad 10 which is set at the origin O to the reference position _{L 0 (δX 0, δY 0} , δZ 0) only by moving parallel, the attracted position confirmation jig 110 adsorption surface 11 of the suction pads 10 An appropriate suction position can be set with respect to the surface 112. Also, the suction pad 10 in the reference position _{L 0 (δX-δX 0,} δY-δY 0, δZ-δZ 0) be moved by parallel, it can be guided this to work position _{L W.}

When storing the reference position L ₀ in the storage unit 60, in the initially adjusted suction device 100, a new suction pad 10 is set at the origin O, and the suction surface 11 is covered with the position check jig 110 under visual confirmation. Move to the suction surface 112. By storing the displacement amount of the suction pad 10 at this time in the storage unit 60 for each axial direction, the control unit 40 can guide the suction pad 10 from the zero point position to the reference position L ₀ thereafter.

The suction pad 10 is provided with the tip of the suction nozzle 33 communicating therewith. The distal end of a flexible air tube 31 is connected to the proximal end of the suction nozzle 33 via a joint 32.
On the other hand, a suction device 34 is connected to the proximal end of the air tube 31. The suction device 34 sucks the air tube 31 and the inside of the suction pad 10 to a negative pressure.
The air tube 31 is provided with an adsorption sensor 30 as a measurement unit between the joint 32 and the suction device 34. In the present embodiment, an air pressure sensor that measures the internal pressure of the air tube 31 is used as the adsorption sensor 30.

A measurement signal SG from the adsorption sensor 30 is input to the control unit 40 through a signal line.
When the internal pressure of the air tube 31 measured by the suction sensor 30 is equal to or lower than a predetermined value, air leakage at the suction pad 10 is substantially zero, and the suction force of the work 120 by the suction pad 10 is sufficiently high. Is determined. On the other hand, when the internal pressure of the air tube 31 measured by the suction sensor 30 is equal to or higher than a predetermined value, significant air leakage occurs in the suction pad 10 and the suction force of the work 120 by the suction pad 10 is insufficient. Determined.

The drive unit 20 that drives the suction pad 10 includes a motor 21, pulleys 22 and 24, a belt 23, a ball screw 25, and an arm unit 26 that drives the entire suction device 100 in the XY direction. Yes.
When the rotational force of the motor 21 is transmitted to the ball screw 25 via the pulley 22, the belt 23, and the pulley 24, the ball screw 25 advances and retreats in the ± Z direction as illustrated.
The lower end of the ball screw 25 and the upper end of the suction nozzle 33 are connected by a coupling 28 and a spring 29.

Here, the zero point position indicating the center of the lower end surface (suction surface 11) of the suction pad 10 varies minutely due to long-term use of the suction device 100 or the like. Specific factors include a rise in the suction surface 11 due to wear of the suction pad 10 in the + Z direction, displacement of the arm portion 26 in an arbitrary direction, plastic deformation, and the like. When the suction surface 11 of the suction pad 10 is worn or the position of the suction pad 10 is shifted, the center position (origin O) of the suction surface 11 of the suction pad 10 moves.
In contrast, the position or confirmation jig 110 arranged in the reference position L ₀ of the suction device 100, with respect to the position of the workpiece 120 is sent by the feed base 130, over time displacement is negligible. This is because the position confirmation jig 110 is fixedly installed on the suction device 100 and is not displaced, and the workpiece 120 is aligned with respect to the feed base 130 with high accuracy by an optical or other method.

FIG. 2 is a schematic diagram showing a state where the suction pad 10 is worn and its suction surface 11 is raised in the + Z direction. Specifically, when the suction surface 11 of the suction pad 10 is raised by ΔZ in the + Z direction, the zero point position of the suction pad 10 is displaced to the origin O ₁ (0, 0, ΔZ).
As a result, the reference position L ₀ of the suction pad 10 is displaced to positions (δX ₀ , δY ₀ , δZ ₀ + ΔZ).
That is, when the suction surface 11 of the suction pad 10 is worn, a gap is generated by ΔZ in the up and down direction between the reference position L ₀ and the suction target surface 112 of the position confirmation jig 110.
Also, the suction pad 10 the zero point position from (origin _{O 1) (δX, δY,} δZ) only is moved parallel to reach the suction surface 11 than the work position _{L W} of + [Delta] Z position (δX, δY, δZ + ΔZ ) It will be.
Therefore, in the suction pad 10 where the suction surface 11 is worn, atmospheric air leaks from the gap between the suction surfaces 112 and 122, and a sufficient suction force cannot be obtained.

FIG. 3 is a schematic diagram showing a state in which the suction pad 10 is displaced by (+ ΔX, + ΔY) in the horizontal direction. Specifically, the zero point position of the suction pad 10 is displaced to the origin O ₂ (ΔX, ΔY, 0).
Thereby, the reference position L ₀ of the suction pad 10 is displaced to a position (δX ₀ + ΔX, δY ₀ + ΔY, δZ ₀ ).
In other words, when there is a positional shift on the suction surface 11, a gap (ΔX, ΔY) is generated in the horizontal direction between the reference position L ₀ and the suction target surface 112 of the position confirmation jig 110. .
Also, the suction pad 10 the zero point position from (origin _{O 2) (δX, δY,} δZ) only is moved parallel position ([delta] X + [Delta] X of the suction surface 11 than the work position _{L W (+ ΔX, + ΔY} ), δY + ΔY, δZ).
Therefore, even in the suction pad 10 in which the positional deviation has occurred, the atmospheric air leaks from the gap between the suction surfaces 112 and 122 and a sufficient suction force cannot be obtained.

Therefore, in the adsorption apparatus 100 of the present embodiment, the measurement unit (suction sensor 30), at the reference position L ₀ and the displacement position L _D where the suction pads 10 in the lifting direction or the cross direction by displacing the predetermined displacement amount ΔL Then, the suction forces F1 and F2 of the suction pad 10 with respect to the suction target surface 112 are measured.

More specifically, the adsorption apparatus 100, the suction force F1 of the suction pads 10 at the reference position L ₀ is measured and that this is the case the predetermined threshold value TH is smaller than that caused wear or misalignment suction pads 10 Detect. As the threshold value TH, a value lower than the suction force obtained by the suction pad 10 without wear is set. However, the threshold value TH is the suction force of the suction pad 10 that is sufficient to suck and hold the workpiece 120, and is set to a value larger than the dead weight of the workpiece 120.

  In the present invention, the determination when the measured adsorption force F1 and the predetermined threshold TH coincide with each other within the range of significant figures is arbitrary. Similarly to the case where it is determined that the suction force F1 is smaller than the threshold value TH, it may be determined that the suction pad 10 is worn or displaced. Alternatively, as in the case where it is determined that the suction force F1 is greater than the threshold value TH, it may be determined that the suction pad 10 is not worn or displaced.

Next, the suction device 100 drives the driving unit 20 to first displace the suction pad 10 by a predetermined amount in the descending direction (−Z direction), and measures the suction force F2 of the suction pad 10.
Here, when the suction surface 11 of the suction pad 10 is worn by ΔZ as shown in FIG. 2, the suction pad 10 is displaced by ΔZ in the descending direction, so that the suction pad 10 is moved to the position confirmation jig 110. An attracting force F2 that abuts the attracted surface 112 and exceeds the threshold TH is obtained. Thus, the adsorption apparatus 100 detects that the wear amount of displacement [Delta] L = [Delta] Z only suction pad 10 from a reference position L ₀ to a displaced position L _D occurs. The displacement amount ΔL is detected as an X, Y, Z direction component.

The same applies not only when the suction surface 11 of the suction pad 10 is worn but also when the suction pad 10 is displaced in the + Z direction. Also in this case, the reference position L ₀ is displaced to (δX ₀ , δY ₀ , δZ ₀ + ΔZ), and the suction force F1 of the suction pad 10 at the reference position L ₀ is smaller than the threshold value TH. Then, by displacing only ΔZ in lowering direction the suction pad 10 to the displacement position L _D, the suction force F2 exceeds the threshold TH.
Therefore, the suction device 100 can handle the wear of the suction surface 11 and the displacement of the suction pad 10 in the + Z direction without distinction.

On the other hand, when the suction surface 11 of the suction pad 10 is displaced in the horizontal direction as shown in FIG. 3, the suction force F2 does not exceed the threshold value TH even if the suction pad 10 is driven in the up-and-down direction.
Therefore, if the suction force F2 of the suction pad 10 does not exceed the threshold value TH even if the suction pad 10 is driven up and down by a predetermined displacement amount, the suction device 100 moves the suction pad 10 in the horizontal direction to change the suction force. Monitor.

That is, when the determination unit 42 determines that the suction force F2 due to the suction pad 10 displaced in the ascending / descending direction or the crossing direction is smaller than the threshold value TH, the control unit 40 causes the driving unit 20 to move the suction pad 10 in the crossing direction or the ascending / descending direction. The suction force F3 of the suction pad at the position (displacement position L _E ) displaced in the crossing direction or the up-and-down direction is measured by the measurement unit (suction sensor 30), and the determination unit determines that the suction force F3 is greater than the threshold value TH. It further has a function of acquiring the displacement amount ΔL when 42 is determined.

  As a result, the suction device 100 can detect the direction and amount even if the suction pad 10 is worn or displaced in any one of the X, Y, and Z directions or in the combined direction.

Here, if worn or positional deviation of the displacement amount ΔL in the suction pad 10 at the reference position L ₀ is detected, that is at the origin O and the work position L _W, the wear or the displacement amount ΔL by the suction pads 10 Misalignment will occur.
Then, the suction device 100 updates the teaching value VT based on the displacement amount ΔL.
Specifically, the suction device 100 stores a value obtained by subtracting the displacement amount ΔL from the teaching value VT in the storage unit 60 as a new teaching value VT.
Then, the suction device 100 translates the suction pad 10 set at the zero point position (the origin O, O ₁ or O ₂ ) by the drive unit 20 by the new teaching value VT. Thereby, the displacement amount ΔL of the suction pad 10 is canceled, and the suction pad 10 can be appropriately set on the suction surface 122 of the work 120.
At this time, by operating the suction device 34 before and after the parallel movement of the suction pad 10 and sucking the air tube 31 and the inside of the suction pad 10 to a negative pressure, the suction pad 10 has a suction force larger than the threshold value TH. The workpiece 120 is vacuum-sucked.
Thereby, according to the suction device 100 of the present embodiment, a suction force exceeding the threshold value TH can be stably obtained, and a suction error of the workpiece 120 does not occur.

<Adsorption method>
FIG. 4 is a flowchart showing an adsorption method according to the present embodiment (hereinafter sometimes referred to as the present method). This method will be described with reference to FIG.

First, an outline of this method will be described.
The method includes a first step of measuring the adsorption force F1 of the suction pads 10 to vacuum suction the workpiece 120 at the reference position L ₀ (step S10), and the measured suction force F1, the threshold value TH predetermined If smaller, the first displacement step (step S12) for displacing the suction pad 10 by a predetermined amount of displacement in the ascending / descending direction with respect to the workpiece 120 or the intersecting direction with respect to the ascending / descending direction, and the suction at the displaced position (displacement position L _D ) A second measurement step (step S14) for measuring the suction force F2 of the pad 10 and a displacement information acquisition step (step S16) for acquiring a displacement amount ΔL when the suction force F2 is greater than the threshold value TH are included.

Next, this method will be described in more detail.
This method automatically corrects the amount of displacement ΔL of the suction pad 10 due to the wear or displacement in the suction device 100 where it is unknown whether the suction surface 11 of the suction pad 10 is worn or displaced. 10 is intended to guide the work position _{L W.}

First, to measure the attractive force F1 in the suction pad 10 which is set in the reference position L _0. Such measurement may be performed at predetermined time intervals in the handling process of the workpiece 120 by the suction device 100.
Specifically, the first measuring step (step S10), the suction pads 10 from the zero point position at _{(δX 0, δY 0, δZ} 0) the reference position _{L 0} that is displaced by, and driving the suction device 34 Then, the air tube 31 is vacuumed and the internal pressure of the air tube 31 is measured by the adsorption sensor 30. When the measurement result of the suction sensor 30 input to the control unit 40 is equal to or less than the predetermined value, the determination unit 42 determines that the suction force F1 is greater than the threshold value TH (step S11: Y). In such a case, it is determined that the suction pad 10 is not worn or displaced. Then, after the suction pad 10 is returned to the origin O, the suction operation of the workpiece 120 is performed based on the teaching value VT stored in the storage unit 60 (step S18).

  When it is determined that the suction force F1 is smaller than the threshold value TH (step S11: N), in this method, the motor 21 of the drive unit 20 is driven to move the suction pad 10 in the downward direction (−Z direction) with respect to the workpiece 120. Displace. Various displacement methods can be used, but in this embodiment, a minute amount (dZ) is displaced (step S12). The minute amount dZ for displacing the suction pad 10 is preferably equal to the resolution of the motor 21. And the raising / lowering drive amount of the drive part 20 is input into the control part 40, and is integrated | accumulated.

Here, in the suction device 100, in order to protect the suction pad 10 and the workpiece 120, a predetermined maximum lifting amount is set in the lifting direction and stored in the storage unit 60. And the control part 40 confirms that the descending amount of the suction pad 10 in a 1st displacement process (step S12) does not exceed the said predetermined maximum raising / lowering amount (step S13).
When the lowering amount of the suction pad 10 is less than or equal to the maximum lifting amount (step S13: N), as a second measurement step, the suction sensor 30 measures the suction force F2 on the suction pad 10 (step S14).
Data indicating the suction force F2 is input from the suction sensor 30 to the control unit 40, and the determination unit 42 determines the magnitude of the threshold TH (step S15).
If it is determined that the suction force F2 is still less than or equal to the threshold value TH (step S15: N), the suction device 100 drives the drive unit 20 again to lower the suction pad 10 (step S12) and Repeat the process.

On the other hand, as shown in FIG. 2, when the suction pad 10 is worn or displaced in the + Z direction, it is determined that the suction force F2 is larger than the threshold value TH by lowering the suction pad 10 by ΔZ. (Step S15: Y). That is, it is detected in the suction device 100 that the zero point position of the suction pad 10 is displaced from the origin O to the origin O ₁ (0, 0, ΔZ).
In such a case, the adsorption device 100 acquires ΔZ as the displacement amount ΔL (step S16) and stores it in the storage unit 60.
In this method, the amount of descending each time the suction pad 10 is constant at the minute amount dZ, and the displacement amount ΔL is obtained by integrating the minute amount dZ, but the present invention is not limited to this. For example, when the first displacement step (step S12) is performed a plurality of times, the suction pad 10 may be displaced again with a different descending amount after the suction pad 10 previously displaced is temporarily returned. In this case, when the suction force F2 larger than the threshold value TH is measured in the second measurement step (step S14), the amount of decrease in the immediately preceding first displacement step (step S12) is set as ΔZ.

Then, the adsorption device 100 subtracts ΔZ from the teaching value VT (δX, δY, δZ) stored in the storage unit 60 and sets the storage unit 60 as (δX, δY, δZ−ΔZ) as a new teaching value VT. Update (step S17). Then, the suction device 100 returns the suction pad 10 to the origin O ₁ (0, 0, ΔZ). Further, the suction pad 10 is moved to the workpiece position L _W (δX, δY, δZ) based on the new teaching value VT (δX, δY, δZ−ΔZ) stored in the storage unit 60, and the workpiece 120 is suctioned. An operation is performed (step S18).

In this method, when the suction force F1 or F2 measured in the first or second measurement step (steps S10 and S14) is both smaller than the threshold value TH, the second suction pad 10 is displaced in the crossing direction or the up-and-down direction. It further includes a displacement step (step S20) and a third measurement step (step S22) for measuring the suction force F3 of the suction pad 10 at the position displaced in the second displacement step (displacement position L _E ).

In this way, in the first third measurement step (step S10, S14, S22), measures the suction force F1~F3 suction pad 10 for localization fixture 110 located at the reference position _{L 0.}

That is, as shown in FIG. 3, when the suction pad 10 is misaligned in the intersecting direction (horizontal direction), the suction pad 11 is lowered in the −Z direction so that the suction surface 11 and the suction target surface 122 of the workpiece 120 are moved. Even if they are brought into contact with each other, the horizontal gap is not eliminated, and air leakage occurs in the suction pad 10.
In such a case, in the determination step (step S15) after the second measurement step (step S14), the lowering amount of the suction pad 10 exceeds the maximum lift amount without the suction force F2 exceeding the threshold value TH (step S13: Y).
The suction device 100 appropriately returns the position of the suction pad 10 in the ascending / descending direction (step S19), and then drives the arm unit 26 to horizontally move the suction pad 10 in the X and Y directions (step S20).
Here, in the suction device 100, a predetermined maximum movement amount is set for each of the X and Y directions in the horizontal direction so that the suction pad 10 and the drive unit 20 do not interfere with other members, and are stored in the storage unit 60. Has been.

  Then, the arm portion 26 is driven to displace the suction pad 10 by a minute amount (dX, dY) in the horizontal direction with respect to the workpiece 120 (step S20). The minute amounts dX and dY for displacing the suction pad 10 are preferably equal to the resolution of the drive motor (not shown) of the arm unit 26. The amount of horizontal movement of the drive unit 20 is input to the control unit 40 and integrated for each of the X and Y directions.

The suction device 100 confirms by the control unit 40 that the horizontal movement amount does not exceed the maximum movement amount in both the X and Y directions (step S21: N), and measures the suction force F3 of the suction pad 10 by the suction sensor 30. (Step S22).
When the suction force F3 is equal to or less than the threshold value TH1 (step S23: N), the arm portion 26 is driven again to horizontally move the suction pad 10 (step S20), and the suction force F3 is measured.

Note that the threshold value TH1 used for the magnitude determination with the suction force F3 is different from the threshold value TH used for the magnitude determination with the suction force F1 or F2 measured in the first or second measurement step (steps S10 and S14). Also good. Specifically, the threshold value TH1 may be set to a value smaller than the threshold value TH.
The horizontal movement of the suction pad 10 (step S20) is preferably performed by slightly separating the suction surface 11 and the suction target surface 122 in consideration of the friction between the suction pad 10 and the position confirmation jig 110. In such a case, the suction force F3 of the suction pad 10 measured in the third measurement step (step S22) may be equal to or less than the threshold value TH even when the suction pad 10 is not displaced. Therefore, in such a case, the suction device 100 stores an appropriate value as the threshold value TH1 in the storage unit 60, and in step S23, the determination unit 42 calls the threshold value TH1 and determines the magnitude of the suction force F3.

When the suction force F3 is larger than the threshold value TH1 (step S23: Y), as the displacement information acquisition step (step S16), the integrated movement amount (ΔX, ΔY) in the X and Y directions is acquired as the displacement amount ΔL. Store in the storage unit 60.
Thereby, in the suction device 100, it is detected that the zero point position of the suction pad 10 is displaced from the origin O to the origin O ₂ (ΔX, ΔY, 0).

Then, the adsorption device 100 subtracts ΔX and ΔY from the teaching value VT (δX, δY, δZ) stored in the storage unit 60, and sets (δX−ΔX, δY−ΔY, δZ) as a new teaching value VT. The storage unit 60 is updated (step S17). The suction device 100 returns the suction pad 10 to the origin O ₂ (ΔX, ΔY, 0), and then sets the new teaching value VT (δX−ΔX, δY−ΔY, δZ) stored in the storage unit 60. Based on this, the suction pad 10 is moved to the workpiece position L _W (δX, δY, δZ). At this position, the workpiece 120 is suctioned with a suction force exceeding the threshold TH (step S18).

That is, in the present method, when the suction force F2 or F3 measured in the second or third measurement step (steps S14 and S22) is larger than the threshold values TH and TH1, the position of the workpiece 120 is determined based on the displacement amount ΔL. A teaching step (step S17) for updating the teaching value VT indicating the suction, and a suction step for vacuum-sucking the work 120 by the suction pad 10 at the suction position L _A (= work position L _W ) based on the updated teaching value VT. (Step S18).

Here, when the suction force F3 does not exceed the threshold value TH1 (step S23: N) and the horizontal movement amount of the suction pad 10 exceeds the maximum movement amount (step S21: Y), the suction pad 10 has an allowable value. It is detected that the positional deviation exceeds or the wear shape of the suction surface 11 is not flat but has a large uneven shape that causes significant air leakage.
In such a case, the suction device 100 determines that it is necessary to check and correct the displacement of the transport mechanism by a maintenance person.

  In the present method, a notification step of performing notification output is performed when the suction force F2 or F3 measured in the second or third measurement step (steps S14 and S22) is smaller than the threshold values TH and TH1 (step S24).

  That is, as shown in FIGS. 1 to 3, the suction device 100 of the present embodiment outputs a notification output when the determination unit 42 determines that the measured suction forces F1 to F3 are all smaller than the threshold values TH and TH1. A notification unit 50 is provided.

  In addition to using an alarm device connected to the control unit 40, the notification unit 50 can be configured by a program for outputting a notification on the display screen of the control unit 40.

  The above steps S10 to S17 and S19 to S24 may be performed intermittently at a predetermined number of times or every predetermined time while repeating the suction holding operation of the workpiece 120 by the suction pad 10 many times. As a result, the suction device 100 can quickly detect the occurrence of wear or misalignment of the suction pad 10 and automatically update the teaching value VT of the workpiece 120 to prevent the occurrence of problems due to suction mistakes. Can do.

The effect of the adsorption device 100 of the present embodiment will be described.
Adsorption apparatus 100 of the present embodiment, when the suction force F1 at the reference position L ₀ of the suction pads 10 is determined to be smaller than the threshold TH, is displaced a predetermined displacement suction pads 10 in the lifting direction or the cross direction Then, the suction force F2 is measured again, the position of the suction pad 10 where the suction force F2 is larger than the threshold value TH is specified, and the displacement amount ΔL is acquired. Thus, since it is detected that the origin O, which is the zero point position of the suction pad 10, is displaced, there is no subsequent maintenance after the suction error of the workpiece 120 occurs, and the operation loss of the suction device 100 is lost. Can be suppressed.
In the suction device 100 of the present embodiment, the suction pad 10 and the workpiece 120 are not optically aligned and positioned, but the position of the origin O and the reference position L ₀ is determined depending on the suction force of the suction pad 10. This is a method for detecting deviation. For this reason, the work 120 does not require a special shape or marking. That is, the suction device 100 is highly versatile in the sense that the suction holding operation can be performed regardless of the workpiece 120.
According to the suction device 100 of the present embodiment, it is possible to detect that the suction surface 11 has been displaced in the up-and-down direction. Therefore, even when the suction surface 11 is worn or displaced in the up-and-down direction, the workpiece is attracted. Mistakes can be prevented.

And the adsorption | suction apparatus 100 of this embodiment updates the teaching value VT which shows the position of the workpiece | work 120 based on this displacement amount (DELTA) L. Thereby, even when the suction pad 10 is worn or displaced, the teaching value VT is automatically taught based on the displacement ΔL. Then, it is possible to always exactly match the suction position L _A is a guide position of the suction pads 10 to the work position L _W of the workpiece 120.

In the suction device 100 of the present embodiment, the position confirmation jig 110 is provided fixed to a known relative position with respect to the workpiece 120. The measuring unit (suction sensor 30), at the reference position _{L 0} and the displacement position _{L D,} the size determination of the threshold TH by measuring the suction force F1, F2 of the suction pad 10 with respect to the suction surface 122 of the workpiece 120 Do. As a result, the suction device 100 can detect wear or displacement of the suction pad 10 using the position confirmation jig 110 as a reference (fixed point). Further, when the suction force F1 to F3 is measured by displacing the suction pad 10 in the ascending / descending direction or the crossing direction, by using the position confirmation jig 110 that is provided apart from the work 120, the work 120 is unpredictable. No external force is given.
In this sense, it is preferable that the attracted surface 112 of the position confirmation jig 110 is provided at a higher position in the ascending / descending direction than the attracted surface 122 of the workpiece 120. Thereby, when the suction pad 10 is displaced in the up-down direction or the crossing direction, the suction pad 10 and the workpiece 120 do not interfere with each other.

In addition, this invention is not limited to a present Example, A various deformation | transformation is accept | permitted in the range which does not deviate from the summary.
For example, in the suction device 100 of the present embodiment, the origin O that is the starting point of the suction holding operation of the workpiece 120 and the reference position L ₀ where the position confirmation jig 110 is provided are set separately. It is not limited to this. The relative position (δX−δX ₀ , δY−δY ₀ , δZ−δZ ₀ ) between the position confirmation jig 110 and the workpiece 120 is stored in the storage unit 60 as the teaching value VT, and the attracted surface of the position confirmation jig 110 You may perform the adsorption | suction holding | maintenance operation | movement of the workpiece | work 120 by making 112 into a starting point (origin 0).

  In the suction device 100 of the present embodiment, the position confirmation jig 110 for measuring the suction force of the suction pad 10 is provided, but the present invention is not limited to this. During the suction holding operation by the suction pad 10, the suction force of the suction pad 10 against the suction target surface 122 of the workpiece 120 is measured by the suction sensor 30 and the control unit 40, and it is determined whether or not this is larger than the threshold value TH. You may determine by. In other words, the wear or misalignment of the suction pad 10 may be detected using the workpiece 120 itself that is the target of suction holding without providing a separate jig for measuring the suction force of the suction pad 10.

In the suction device 100 of the present embodiment, the teaching value VT is updated based on the displacement amount ΔL indicating wear or displacement of the suction pad 10, but the present invention is not limited to this. The teaching value VT stored in the storage unit 60 may be unchanged and the deviation of the zero point position of the suction pad 10 may be adjusted. Specifically, the suction pad 10 at the zero point position (the origins O ₁ , O ₂ ) is moved in the reverse direction by the amount of displacement ΔL acquired in the displacement information acquisition step (step S16), thereby attracting the suction pad 10. The origin of the pad 10 can be adjusted. Such position (origin O), by updating the original position of the suction pads 10, without updating the teaching value VT, can be guided accurately suction pad 10 to the work position L _W the origin O as a reference .

  Moreover, in the adsorption | suction apparatus 100 of this embodiment, although the 2nd displacement process (step S20) is performed after the 1st displacement process (step S12), this invention is not limited to this. That is, the suction pad 10 may be first moved horizontally to determine the suction force, and then moved up and down to remeasure the suction force. Alternatively, the first displacement step (step S12) and the second displacement step (step S20) may be repeated a plurality of times in an arbitrary order.

Further, in the present embodiment, the suction sensor 30 that measures the internal pressure of the air tube 31 is used as the measurement unit that measures the suction force of the suction pad 10, but the present invention is not limited to this. For example, by installing a load sensor under the position confirmation jig 110 and monitoring the weight of the position confirmation jig 110, the suction force by the suction pad 10 is replaced with the gravity load of the position confirmation jig 110 and measured. May be.
Or, if a flow meter is used in place of the suction sensor 30, whether or not airflow leakage occurs in the suction pad 10 depending on whether or not the flow rate of the airflow flowing through the air tube 31 gradually decreases to zero when the suction device 34 is driven. It may be determined whether or not. If the flow rate in the air tube 31 when the predetermined time has elapsed from the start of suction by the suction pad 10 with respect to the suction surface 112 of the position confirmation jig 110 is less than a predetermined threshold, there is no air leakage in the air tube 31. Therefore, it can be detected that the suction pad 10 has a sufficient suction force.

It is a schematic diagram which shows an example of the adsorption | suction apparatus concerning 1st embodiment of this invention. It is a schematic diagram which shows the state which the suction pad was worn out and the suction surface rose in the + Z direction. It is a schematic diagram which shows the state in which the suction pad was displaced by (+ ΔX, + ΔY) in the horizontal direction. It is a flowchart which shows the adsorption | suction method concerning this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Suction pad 11 Suction surface 20 Drive part 21 Motor 22, 24 Pulley 23 Belt 25 Ball screw 26 Arm part 28 Coupling 29 Spring 30 Suction sensor 31 Air tube 32 Joint 33 Suction nozzle 34 Suction device 40 Control part 42 Determination part 50 Notification part 60 storage unit 100 adsorber 110 localization fixture 112 object face 120 work 122 object face 130 feed bar ΔL displacement F1~F3 suction force _{L 0} reference position _{L A} suction position _L D, _{L E} displacement position _{L W} Work position O, O ₁ , O ₂ Origin TH, TH1 Threshold value VT Teaching value

Claims (10)

A suction pad for vacuum-sucking workpieces;
Driving means for driving the suction pad in the up-and-down direction with respect to the workpiece, or in the crossing direction with respect to the up-and-down direction;
Measuring means for measuring the suction force of the suction pad;
Determination means for determining the magnitude of the measured adsorption force and a predetermined threshold;
When the measuring means measures the suction force at the reference position of the suction pad and the determination means determines that the measured suction force is smaller than the threshold value, the driving means raises and lowers the suction pad. The predetermined displacement amount is displaced once or a plurality of times in the direction or the crossing direction, and the measuring unit measures the suction force of the suction pad at the displaced position, and the determination unit determines that the suction force is greater than the threshold value. Control means having a function of acquiring the amount of displacement when determined by;
An adsorption device comprising: And further comprising storage means for storing a teaching value indicating the position of the workpiece,
The suction device according to claim 1, wherein the teaching value is updated based on the amount of displacement. A position confirmation jig having a suction surface larger than the suction pad and fixed to a known relative position with respect to the workpiece;
The suction device according to claim 1, wherein the measuring unit measures a suction force of the suction pad with respect to the suction target surface at the reference position and the displaced position. The control means includes
When the determination means determines that the suction force by the suction pad displaced in the ascending / descending direction or the intersecting direction is smaller than the threshold value,
The suction pad is displaced in the intersecting direction or the ascending / descending direction by the driving means,
While measuring the suction force of the suction pad at the position displaced in the crossing direction or the up and down direction by the measurement means,
The suction device according to claim 1, further comprising a function of acquiring the amount of displacement when the determination unit determines that the suction force is greater than the threshold value.   The suction device according to claim 4, further comprising notification means for outputting a notification when the determination means determines that all of the measured suction forces are smaller than the threshold value. A first measurement step for measuring the suction force of a suction pad for vacuum-sucking a workpiece at a reference position;
A first displacement step of displacing the suction pad by a predetermined displacement amount in a lifting direction with respect to the workpiece or in a crossing direction with respect to the lifting direction when the measured suction force is smaller than a predetermined threshold;
A second measurement step of measuring the suction force of the suction pad at the displaced position;
A displacement information acquisition step of acquiring the amount of displacement when the suction force is greater than the threshold;
An adsorption method comprising: A second displacement step of displacing the suction pad in the intersecting direction or the ascending / descending direction when both of the suction forces measured in the first or second measurement step are smaller than the threshold value;
A third measurement step of measuring the suction force of the suction pad at the position displaced in the second displacement step;
The adsorption method according to claim 6, further comprising:   The suction method according to claim 7, wherein the suction force of the suction pad with respect to the position confirmation jig disposed at the reference position is measured in the first to third measurement steps. A teaching step of updating a teaching value indicating the position of the workpiece based on the amount of displacement when the suction force measured in the second or third measuring step is larger than the threshold;
A suction step of vacuum-sucking the workpiece with the suction pad at a suction position based on the updated teaching value;
The adsorption method according to claim 7 or 8, further comprising:   The suction method according to claim 7, further comprising a notification step of performing notification output when the suction force measured in the second or third measurement step is smaller than the threshold value.

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