JP2021117139A - Method for measuring thickness of sheet-like article to be conveyed and method of conveyance - Google Patents

Abstract

To provide a method for measuring the thickness and the number of sheets of the article to be conveyed, when holding and conveying a sheet-like article to be conveyed, such as paper and cloth having high insulation properties, while preventing damage to or deformation of it as much as possible, and a method of conveyance using the same.SOLUTION: Provided is a method for measuring the thickness of a sheet-like article to be conveyed while being kept in hold, when the article to be conveyed is gasped and conveyed, and a method of conveyance using the same. Said measuring method includes the steps of: gasping the article to be conveyed, using grasping means equipped with a compliance control mechanism; pressing the article to be conveyed while being kept in hold against a prescribed measurement plane; and measuring a displacement value in the thickness direction when the operation of the gasping means is stopped by the compliance control mechanism when the article is pressed. The measured displacement value is compared with a previously set reference value, and the thickness of the article to be conveyed that is kept in hold is thereby measured. There is also provided a method of conveyance using the method for measuring the thickness of the sheet-like article to be conveyed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for measuring the thickness of a sheet-shaped object to be conveyed and a method for conveying the thickness of the object to be conveyed. The present invention relates to a method capable of measuring the number of sheets.

Conventionally, several means for gripping and transporting sheet-shaped objects to be transported such as paper and cloth have been reported, and in particular, means for peeling, gripping, and transporting one by one from a plurality of stacked cloths and the like have been reported. Has been done. For example, an adhesive tape is used as a holding portion for an object to be adsorbed, but the adhering surface is devised (see Patent Document 1), or a hooking roller having a plurality of hooking needles on the surface of the roller is used. (Refer to Patent Document 2), a method in which these adhesive tapes, needles, or the negative pressure of air is used as a gripping portion, and air is blown onto a piled cloth or the like to devise peeling (see Patent Document 3). In a robot hand for gripping cloth equipped with a presser foot and a picking finger, the presser finger has a cloth sandwiching surface at the tip portion, and the picking finger has a sharp tip portion inserted under the cloth to be gripped. A method of providing a cloth holding surface for sandwiching the cloth between the holding finger and the cloth holding surface of the holding finger, and providing a visual sensor on the holding finger or the picking finger to detect the position of inserting the picking finger at the edge of the cloth. (See Patent Document 4) has been reported.
However, these methods have the following problems. That is, in the method using the adhesive tape as in Patent Document 1, the adhesive strength is weakened and replacement is required, which increases the cost, and also requires some ingenuity when peeling the adsorbed object from the adhesive tape. There is a problem, and the method of hooking and gripping with a needle as in Patent Document 2 is not preferable because there is a risk of damaging the object to be adsorbed, and further, the object to be adsorbed as in the method of Patent Document 3. In the method using negative pressure or compressed air for gripping and peeling, in addition to the problem that adsorption marks remain on the object to be adsorbed, there is a problem that a compressor is required and the size of the device becomes large. .. Further, also in the method described in Patent Document 4, the force is likely to be concentrated on the portion where the cloth is picked, and the cloth may be damaged or deformed.

On the other hand, apart from the above-mentioned method, a method of utilizing adsorption by electrostatic force has been reported as a method of gripping and transporting a sheet-shaped object to be transported such as a cloth in which air leakage occurs. For example, in Patent Document 5, a method of irradiating electrons or ions from a charging device (charging gun) used in combination to charge a grip portion (first grip piece 17) or an object to be adsorbed (conveyed object 101), or It has been reported that an electrostatic chuck or the like is used as the grip portion (first grip piece 17). Further, conventionally, a technique related to an electrostatic chuck has been reported for adsorption / holding when processing a semiconductor substrate or a glass substrate, and an electrostatic adsorption structure to which the technique is applied has been proposed.

For example, in Patent Document 6, a plurality of sheet members in which two dielectrics are sandwiched between electrodes are laminated, and by applying a voltage between the electrodes, the members can be adsorbed and fixed to each other, and paper is applied to other adsorption surfaces. It is highly convenient to change the configuration so that the display / bulletin board such as resin sheets can be adsorbed, and the sheet members and the objects to be adsorbed can be easily separated by cutting off the voltage after use. An electrostatic adsorption structure has been proposed. Further, for example, in Patent Document 7, the surface of an electrostatic chuck in which an adsorption electrode is sandwiched between two insulating layers is used as an attachment / detachment means, and a film-shaped solar cell is attached thereto to improve the selectivity of the installation location. A power generation device with good detachability has been proposed. The electrostatic adsorption structure of Patent Document 6 and the power generation device of Patent Document 7 have good detachability by using the adsorption principle of the electrostatic chuck, and although they are thin and devised for handleability, they are dielectric. The volume resistivity of the polyimide film and polyethylene terephthalate (PET) film used as the layer (insulator) is as high as 1 x 10 ¹⁷ Ω · cm, and it is presumed that the object to be adsorbed is adsorbed by the Coulomb force. Therefore, in particular, it was not always possible to exhibit a strong adsorptive force on a cloth having high insulating properties.
Further, even if the suction force can be satisfied, the suction method using the electrostatic force as described in Patent Documents 5 to 7 can surely grip one sheet at a time from a plurality of stacked cloths or the like. In some cases, it was not possible, or it was not possible to easily confirm that one piece was actually gripped in a series of manufacturing processes.

Here, a method of confirming whether or not the number of objects to be transported is the target number of sheets or the like by detecting the thickness has been conventionally reported. For example, Patent Document 8 describes a method / apparatus for measuring the thickness of paper sheets in order to confirm whether or not the paper sheets have been sent in an overlapping manner. Further, Patent Document 9 describes a method / apparatus for detecting a change in thickness in an enclosed object or a booklet sandwiching a postcard in order to prevent the postcard from coming off or being erroneously enclosed. Further, in Patent Document 10, in order to detect whether or not foreign matter such as cutting residue is attached to the plastic bag, the thickness thereof is measured and the measured thickness is compared with a preset reference value. The identification method / device is described.
However, all of the methods and devices described in Patent Documents 8 to 10 detect and measure the thickness based on the displacement amount of the roller and related equipment (arm, etc.) during transportation by the roller. Therefore, it is difficult to measure without deforming a soft cloth or the like. Further, for example, if the material of the roller is made soft in order to prevent deformation or breakage, it becomes difficult to measure the displacement of a thin or small object. Moreover, for the purpose of peeling one sheet from a plurality of stacked cloths, a mechanism different from the methods described in Patent Documents 8 to 10 is still required.

JP-A-62-244830 Japanese Unexamined Patent Publication No. 6-178883 Japanese Unexamined Patent Publication No. 7-68066 Japanese Unexamined Patent Publication No. 4-303494 Japanese Unexamined Patent Publication No. 2014-30887 WO2011 / 001978 Gazette WO2012 / 128147 Japanese Unexamined Patent Publication No. 9-304002 Japanese Unexamined Patent Publication No. 9-287939 Japanese Unexamined Patent Publication No. 2008-207916 WO2008 / 041457 JP-A-2017-177280 Japanese Unexamined Patent Publication No. 2018-051765

As described above, the method using the physical gripping means as described in Patent Documents 1 to 4 has problems such as damage and deformation of the transported object. Further, in the conventional electrostatic chuck or the like using the electrostatic force as described in Patent Documents 5 to 7, there is a case where a sufficient attractive force cannot be exhibited for the object to be transported having high insulating property, or Even if the suction force is sufficient, it is not possible to reliably grip one sheet at a time from a stack of a plurality of sheets, or it is not possible to easily confirm the gripping of one sheet in a series of steps. Further, in order to detect and measure the number of objects to be transported during transportation, only a method of performing transportation with a roller as described in Patent Documents 8 to 10 has been reported.

Therefore, the inventors of the present application focused on the compliance control technology. Compliance control is a control that includes a method of estimating and controlling the force applied to an object by the arm in order to flexibly control an industrial robot such as a robot arm and operate it so that it fits the object softly. Therefore, it is a technology that can realize processing that suppresses excessive contact with an object, load, and the like. Although some application examples incorporating such compliance control technology have been reported (see, for example, Patent Documents 11 to 13), it is used for transporting and checking the number of sheets to be transported such as paper and cloth. There are no reports applied to it.

Based on such a conventional technique, the present invention is a compliance method in a method of gripping and transporting a relatively thin sheet-shaped object to be transported such as paper or cloth while preventing damage or deformation as much as possible. By using a gripping means equipped with a control mechanism, it is possible to measure the thickness of the transported object gripped in a series of transport steps, and thereby confirm the number of gripped objects to be transported. It was done.

Therefore, an object of the present invention is, in particular, when gripping and transporting a sheet-shaped transported object such as paper or cloth having high insulating properties while preventing damage or deformation as much as possible, the thickness of the transported object. And a method of measuring the number of sheets and a transport method using the same.

That is, the gist of the present invention is as follows.
[1] A method of measuring the thickness of a sheet-shaped object to be transported while grasping the object to be transported.
A step of gripping the object to be transported using a gripping means provided with a compliance control mechanism, a step of pressing the gripped object to be transported against a predetermined measurement surface, and a step of pressing the gripped object against a predetermined measurement surface, and the gripping means by the compliance control mechanism when pressed. It has a process of measuring the displacement value in the thickness direction when the operation of
A method for measuring the thickness of a sheet-shaped object to be transported, which comprises measuring the thickness of a gripped object to be transported by comparing the measured displacement value with a preset reference value.
[2] The reference value is a displacement value when the gripping means is pressed against a predetermined measurement surface without gripping the object to be transported, and when the gripping means is pressed, the operation of the gripping means is stopped by the compliance control mechanism. The method for measuring the thickness of a sheet-shaped object to be transported according to [1], which is obtained by measuring.
[3] In advance, the speed and / or the pressing pressure when the gripping means is pressed against the predetermined measurement surface, parameters related thereto, and the thickness direction when the operation of the gripping means is stopped by the compliance control mechanism. The method for measuring the thickness of a sheet-shaped object to be transported according to [1] or [2], wherein the thickness of the object to be transported is measured after confirming the relationship with the displacement value of.
[4] The method for measuring the thickness of a sheet-shaped object to be transported according to any one of [1] to [3], wherein the gripping of the object to be transported is by electrostatic adsorption.
[5] The sheet shape according to any one of [1] to [4], wherein the gripping means is a robot hand provided with an electrostatic chuck that sucks and grips the object to be transported by electrostatic suction force. Method for measuring the thickness of the object to be transported.
[6] The electrostatic chuck has a laminated sheet in which an insulator having a thickness of 20 to 200 μm, an electrode layer having a thickness of 1 to 20 μm, and a resin film having a thickness of 20 to 200 μm are sequentially laminated, and a voltage on the electrode layer. The resin film has a tensile elasticity of at least 1 MPa or more and less than 100 MPa, a volume resistance of 1 × 10 ¹⁰ to 10 ¹³ Ω · cm, and the electrode layer. It consists of a bipolar electrode having a positive electrode and a negative electrode, and the resin film is used as an adsorption surface to adsorb an object to be transported as an object to be adsorbed by an electrostatic adsorption force generated by applying a voltage to the electrode layer. The method for measuring the thickness of a sheet-shaped object to be transported according to [5].
[7] A method of grasping and transporting a sheet-shaped object to be transported.
At the transport source, a step of grasping the object to be transported by using the method according to any one of [1] to [6] and measuring the thickness of the object to be transported while gripping the object to be transported, and a step of measuring the thickness of the object to be transported, and the thickness of the object to be transported. A method for transporting a sheet-shaped object to be transported, which comprises a step of transporting the object to a transfer destination.
[8] The step of pressing the gripped object to be transported against the mounting surface at the transport destination or the upper surface of the stacked objects to be transported, and when the pressed object is pressed, the operation of the gripping means is stopped by the compliance control mechanism. It has a process to measure the displacement value at the time.
The sheet shape according to [7], wherein the thickness of the gripped object to be transported or the total thickness of the object to be transported laminated at the transfer destination is measured based on the measured displacement value. Method of transporting the object to be transported.

According to the present invention, it is possible to grip and transport a sheet-shaped object to be transported such as paper or cloth having high insulating properties while preventing damage or deformation as much as possible, and a series of gripping and transporting the same. In the process of, the thickness and the number of sheets to be transported can be measured. Therefore, it contributes to mechanize and automate the work of grasping one sheet from the piled cloth, checking the number of sheets, and transporting and checking the number of cloths, which was conventionally performed manually. Then, by using the technique of the present invention, for example, it becomes possible to improve the productivity of garment products by improving the efficiency of sewing work in a garment factory, and it is expected to be expanded to fields and industries such as apparel, for example. NS.

FIG. 1 is a schematic view showing an example of an apparatus used when carrying out the thickness measuring method of the present invention. FIG. 2 is a schematic view showing an example of the operation of the apparatus when the thickness measuring method of the present invention is carried out, (i) shows a case where the object to be transported is not gripped, and (ii) is a case where the object to be transported is not gripped. Is shown when the is gripped. In both (i) and (ii), the left figure shows the state before operation (state before pressing), and the right figure shows the state after operation (state after pressing). The white arrow in the figure indicates the pressing direction. FIG. 3 is a schematic view for explaining a bipolar electrode (hereinafter, this may be referred to as a “flat plate”) used in the electrostatic chuck A (laminated sheet) according to Production Example 1. (I) is a plan view, and (ii) is a cross-sectional explanatory view in the XX cross section. [The numerical values in the figure indicate that the electrode width is 30 mm and the electrode spacing (pitch) is 2 mm. Is]. FIG. 4 is a plan view for explaining a bipolar electrode (hereinafter, this may be referred to as “comb-shaped”) used in the electrostatic chuck B (laminated sheet) according to Production Example 2. [The numerical values in the figure indicate that the width (electrode width) of each comb tooth is 10 mm and the electrode spacing (pitch) is 2 mm]. FIG. 5 is an explanatory photograph for explaining the method of evaluating the adsorptivity of the electrostatic chuck performed in the experimental example. White arrows in the figure indicate the horizontal direction. FIG. 6 is a schematic explanatory view of the methods of the preliminary experiment and Test Examples 1 to 8 performed using a robot hand equipped with a compliance control mechanism. FIG. 7 is a graph showing the results of Test Example 1, and is a graph showing the relationship between the operating speed and the displacement value of the z-axis for each current limit value. FIG. 8 is a graph showing the results of Test Example 2, and is a graph showing the relationship between the operating speed and the displacement value of the z-axis for each control force. FIG. 9 is a graph showing the results of Test Example 3 and is a graph showing the relationship between the control force and the displacement value of the z-axis for each current limit value. FIG. 10 is a graph showing the results of Test Example 4, and is a graph showing the relationship between the control force and the displacement value of the z-axis for each operating speed. FIG. 11 is a graph showing the results of Test Example 5, and is a graph showing the relationship between the current limit value and the displacement value of the z-axis for each control force. FIG. 12 is a graph showing the results of Test Example 6 and is a graph showing the relationship between the current limit value and the displacement value of the z-axis for each operating speed. FIG. 13 is a graph showing the results of Test Example 7, and is a graph showing the relationship between the current limit value and the displacement value on the z-axis for each number of pieces of cloth. FIG. 14 is a graph showing the results of Test Example 8 and is a graph showing the relationship between the number of cloths and the displacement value of the z-axis (thickness of the gripped cloth pieces) when the type of cloth pieces is changed. ..

Hereinafter, the present invention will be described in detail.
The outline of the method of the present invention is shown in FIGS. 1 and 2. In the present invention, in the method of measuring the thickness of the transported object, a gripping means for gripping the transported object is indispensably provided, and the gripping means includes a compliance control mechanism. That is, the method of the present invention is at least i) a step of gripping the transported object by using a gripping means provided with a compliance control mechanism, ii) a step of pressing the gripped object to be transported against a predetermined measurement surface, iii. ) It has a step of measuring the displacement value in the thickness direction of the object to be transported when the operation of the gripping means is stopped at the time of pressing. Then, iv) the measured displacement value is compared with a preset reference value.

First, the above i) will be described.
The object to be transported in the present invention is not limited as long as it is in the form of a sheet, but in particular, it has a high insulating property and is unlikely to generate an electrical adsorption force, and has a volume resistivity of 10 ¹² Ω such as cloth, paper, and resin.・ The target is about cm to ^{10 14 Ω ・ cm.} There are no particular restrictions on the shape and size of the object to be transported because it depends on the gripping means used and the equipment / devices including it, and the area that is not suitable for transportation by rollers is small (for example, 100 mm). ^{(About 2} ) can also be targeted. Further, a wide range of objects from thin to thick can be used, but from the viewpoint of measurement accuracy (discrimination accuracy of sheet number detection), it is preferable to use one having a thickness of 0.04 mm or more. For those with a large area, it is possible to determine whether or not it is applicable in relation to the gripping means, but it is preferable that the area is not too large compared to the gripping means, for example, a predetermined suction surface such as an electrostatic chuck. When the gripping means to be held is used, it is preferable that the area of the object to be transported is smaller than the area of the suction surface in order to prevent the end portion from being bent or bent. As for the surface shape (state) of the object to be transported, it is often used that the surface shape (state) is relatively smooth without having a complicated shape or unevenness, and the surface shape (state) of a general-purpose cloth, paper, or the like is used. ) Is preferable.

Here, the means for gripping the object to be transported may be any means as long as one or a plurality of sheets can be taken out (lifted) from the object to be transported stacked at the transfer source and transported to the transfer destination. Any known operation such as grasping, grasping, picking, scooping, placing, adhering, and adsorbing a transported object can be adopted. In addition, the parts other than those that come into contact with the object to be transported are those that move linearly, or those that have multiple joints and move flexibly, depending on the process and equipment to be applied. Can be changed. The contact portion with the object to be transported may be provided with a gripping means utilizing adsorption by electrostatic force. By using adsorption by electrostatic force, it is possible to grip while preventing damage or deformation of the object to be transported as much as possible, and it is also easy to release (release) the object to be transported by turning on / off the voltage application. Is. Further, from the viewpoint of being able to flexibly respond to various gripping / transporting operations, it is preferable to use an articulated robot hand (arm), and more preferably, a robot equipped with a gripping means that attracts by electrostatic force at the tip. It should be a hand (arm).

It is preferable to use an electrostatic chuck as the gripping means that attracts by electrostatic force. In particular, when targeting paper or cloth with high insulation properties, those using a polyimide or polyester dielectric layer (insulator) that has been conventionally used for processing semiconductor substrates and glass substrates can also be used. However, it is preferable that a stronger adsorptive force can be exhibited, and it is preferable to use an electrostatic adsorbent having the following configuration. That is, as illustrated in FIGS. 3 and 4, at least the resin film serving as the adsorption surface for the object, the electrode layer, and the insulator are sequentially laminated, and the electrode layer is insulated from the resin film. It is provided with a power supply device (not shown) that forms a laminated sheet sandwiched between the body and applies a voltage to the electrode layer, and the electrode layer is a static electrode having a bipolar electrode having a positive electrode and a negative electrode. It is preferably an electroadsorbent, and the resin film, insulator, electrode layer, and laminated sheet thereof used are as follows.

<Resin film>
^{Here, as a preferable resin film, the volume resistivity is 1 × 10 10} to 10 ¹³ Ω from the viewpoint of ensuring the adsorption force for paper or cloth and reducing the damage to the transported object due to the generation of leakage current. It is preferably cm. ^{More preferably, the volume resistivity is 1 × 10 10} to 10 ¹² Ω · cm from the viewpoint of the development of adsorption force and safety.

Further, the resin film preferably has a tensile elastic modulus (Young's modulus) of 1 MPa or more and less than 100 MPa. Having such a tensile elastic modulus (Young's modulus) enables adsorption following the shape of the object to be transported. Further, when the objects to be transported are adsorbed one by one, it is preferable to make the shape into a roll shape or the like so that the adsorption surface has a curved surface.

The thickness of the resin film is preferably 20 to 200 μm, preferably 50 to 100 μm, in order to ensure insulation, flexibility, adsorption followability to the object to be adsorbed, and adsorption force. It is good to do. If the thickness is less than 20 μm, dielectric breakdown is likely to occur, and if it exceeds 200 μm, the adsorption followability and flexibility to the object to be adsorbed will be inferior and the distance from the electrode layer will be large. Therefore, the adsorption force may decrease.

Examples of the resin film as described above include polyimide, polyethylene terephthalate (PET), nylon, polypropylene, polyurethane, soft polyvinyl chloride, polyvinylidene chloride, etc., or processed to adjust their conductivity. (Mixed with a filler, etc.) can be used, but polyurethane and soft polyvinyl chloride are preferable, and more preferably, in order to keep the volume resistance and tensile elasticity within the above ranges. It is soft polyvinyl chloride. That is, as the resin film, soft polyvinyl chloride satisfying the above-mentioned volume resistivity and tensile elastic modulus is most preferable.

<Insulator>
Further, as the insulator used on the side opposite to the adsorption surface with the object to be transported, the same insulator as the resin film may be used, or may be different, but the volume of the resin film. It is preferable to use one having the same resistivity or a larger volume resistivity than that. This is to prevent a current that should flow between the resin film and the object to be transported from flowing to the insulator side. Further, in order to develop flexibility, it is preferable that the tensile elastic modulus (Young's modulus) of the insulator is about the same as the tensile elastic modulus (Young's modulus) of the resin film. The thickness of the insulator is preferably 20 to 200 μm, more preferably 50 to 100 μm.

A preferable insulator is the same as the resin film, or ceramics such as aluminum nitride and alumina, and a more preferable insulator is one used for the resin film.

<Electrode layer>
As the electrode layer (including a single-layer electrode), a bipolar type is preferable. If the unipolar type is to be used, it will be necessary to arrange the electrodes on the side of the object to be transported, but this is because it is difficult to arrange the electrodes when the object to be transported is cloth. The material and shape of the electrode layer are not particularly limited, but the thickness is preferably 1 to 20 μm in order to suppress deformation when the electrode layer is too thin and deterioration of flexibility when the electrode layer is too thick. For example, the metal foil itself, a metal formed by a sputtering method, an ion plating method, or the like etched into a predetermined shape, or a metal material is sprayed or a conductive ink is printed to obtain a predetermined shape. It may be shaped.

Here, as the shape of the bipolar electrode, for example, a flat plate shape, a semicircular shape, a pattern shape such as a comb tooth shape or a mesh, or the like can be appropriately selected, but a pair of comb tooth shape electrodes is preferable. Is preferable, and more preferably, as shown in FIG. 4, it is often used that the comb teeth in the pair of comb-shaped electrodes are formed by meshing with each other on the same plane while maintaining a constant distance from each other. , It is preferable because the adsorption force can be more strongly expressed with respect to the object to be transported. Although the detailed principle is not clear, when a pair of comb-shaped electrodes as described above is used, a gradient force is developed between the pair of comb-shaped electrodes and a sheet-like insulator such as paper or cloth, and general positive electrodes and negative electrodes are used. It is considered that a stronger adsorption force is exhibited as compared with the case of using a flat plate-shaped bipolar electrode made of.
As a bipolar electrode in which the comb teeth of the pair of comb-shaped electrodes mesh with each other on the same plane while maintaining a constant distance from each other, the width (electrode width) of each comb tooth is preferably 0.5 to 20 mm. Further, the distance (pitch) between the comb teeth is preferably 0.5 to 10 mm, more preferably the width (electrode width) of each comb tooth is 1 to 10 mm, and the above-mentioned The distance (pitch) between the comb teeth should be 1 to 2 mm. By setting the width (electrode width) of each comb tooth to 1 mm or more, the workability of the electrode can be improved, while by setting the width to 10 mm or less, a decrease in adsorption force can be suppressed. Further, the discharge between the electrodes can be suppressed by setting the distance (pitch) between the comb teeth to 1 mm or more, while the decrease in the adsorption force can be suppressed by setting the distance between the comb teeth to 2 mm or less. ..

<Laminated sheet>
Then, the resin film, the electrode layer, and the insulator are laminated to form a laminated sheet, and it is preferable that the resin film, the electrode layer, and the insulator are sandwiched so as not to be exposed. Specific examples of the production method include a method in which a resin film, an electrode layer and an insulator are sequentially laminated and fused by applying heat and pressure. Alternatively, it may be bonded via a bonding sheet or an adhesive or an adhesive, but if another material such as an adhesive layer is inserted, deformation and expansion / contraction may be hindered, or the adhesive surface may be peeled off. Therefore, the method of fusing is preferable.

As the laminated sheet, a flat plate in which a resin film, an electrode layer and an insulator are laminated may be used as it is, or may be changed to a shape according to the object to be transported. For example, by rolling the laminated sheet on the surface of the object to be transported so that the suction surface of the laminated sheet has a curved surface, it is possible to approach the operation of peeling (turning up) the objects to be transported one by one. In this case, the radius of curvature R of the roll shape is preferably about 25 mm.
Further, if the area of the suction surface of the laminated sheet is smaller than the area of the object to be transported, the influence of the adsorption force on the second and subsequent objects to be adsorbed from the outer peripheral side of the laminated sheet can be eliminated as much as possible. As a result, the objects to be transported can be peeled off one by one. Preferably, the area of the suction surface of the laminated sheet is about 80% of the area of the object to be transported.

<Power supply>
As for the power supply device for applying a voltage to the electrode layer of the laminated sheet, as long as it can be connected to the electrode layer of the laminated sheet via a connection terminal and a switch and can generate a high DC voltage. The same one used in a general electrostatic adsorption structure can be used. The potential difference to be generated can be about ± 100 to ± 5000 V, and if necessary, a booster circuit (high voltage generation circuit) capable of boosting to a required voltage may be provided.

Next, as described above, the gripping means (and the device for transport connected thereto; these may be collectively referred to simply as "grasping means") in the present invention includes a compliance control mechanism. Any known compliance control technique can be adopted as the compliance control, but since the present invention includes a step of pressing the gripped object to be transported against a predetermined measurement surface, at least the contact force against the measurement surface is constant. Try to stop the operation to keep it. The stop time can be set as appropriate, but at least a time suitable for measuring a predetermined displacement value of the gripping means is preferable. In addition, in the actual work process, it is preferable to set the tact time and the like in consideration, and the stop in the present invention may include a very short momentary stop.

Here, the compliance control is performed by a controller provided with, for example, a central processing unit (CPU), a memory, an input / output device, etc., in the same manner as the control of the operation of the gripping means such as a robot hand. Taking the robot hand as an example, the controller is connected to the motor of each axis (joint) of the robot hand and controls the operation while monitoring the joint angle (encoder value) and acceleration / force (current value). ing. The user can use such a controller to give an operation instruction to a gripping means such as a robot hand, but the controller has a program for automatic operation and a reference for cloth thickness as described later. Information such as values can also be saved.

Then, in the compliance control, the operation of the gripping means is adjusted while the controller monitors the encoder value.
Here, in the case of normal position control that is not compliance control, the controller moves the motor until the encoder value reaches the specified value (until the joint angle reaches the angle specified by the user), hits something, etc. Even when a load is applied, the gripping means such as the robot hand is forced to operate by increasing the current (generating a larger force). On the other hand, in the case of compliance control, even if the gripping means such as the robot hand is loaded as described above, the increased current is set to the upper limit value (current limit value). It is adjusted so that it does not exceed, and as a result, the force for pushing the bumped object is controlled to be weaker than in the case of position control. That is, in compliance control, by setting the upper limit of the current acting on the shaft (joint) or the like related to the operation of the gripping means, the upper limit of the force that the shaft (joint) can exert can be set.

Taking a robot hand equipped with a compliance control mechanism as an example, the following is performed. That is, when the next posture is instructed / specified to the robot hand in the controller, the controller applies a current to the motor of the shaft (joint) of the robot hand so as to try to make the posture, thereby causing the current to flow. The corresponding torque is generated and the robot starts to move. Next, when the robot hand comes into contact with the measurement surface or the like, there is a difference between the position / speed of the robot hand corresponding to the current value passed and the position / speed of actual operation, and the difference causes the robot hand. Since it is related to the contact force at the time of contact with the measurement surface, the current value (current limit value), the target control force, and the operating speed are changed as necessary. The target control force is a force for controlling a robot hand or the like, and when this value is reduced, the robot moves according to a small external force. If the current limit value is set to zero, it can be pushed back with the force according to the target control force, but then the robot cannot move by itself, for example, it can not even push against the measurement surface, so in that case each robot hand Adjust the current value (current limit value) flowing through the shaft (joint). At the same time, the operating speed is also adjusted in order to prevent rebounding due to overshoot (sinking when the measuring surface or the like has cushioning properties) when it comes into contact with the measuring surface or the like. Change one or more of the current value (current limit value), target control force, and speed according to the material to be transported and the material used for the measurement surface, taking into consideration the degree of deformation of the object to be transported. Is preferable.

Other parameters related to compliance control include the following. First, in order to prevent an error (operation stop) due to a deviation between the target position and the actual position that occurs when operating according to an external force, the target position deviation allowance and each axis deviation allowance are adjusted. Further, the compliance control is a control that operates like a spring, but in a gripping means such as a robot hand, the farther the tip position is from the target position, the stronger the force tends to move to the target position. Therefore, the softness of the virtual spring (that is, the degree of the strength of the return force) can be adjusted and set. In addition, it is possible to adjust and set the "viscosity" assuming what kind of viscous liquid such a virtual spring is in. When the "viscosity" is set, the ratio of the resistance force according to the speed, that is, the ease of acceleration according to the speed of the gripping means can be adjusted. That is, the smaller the "viscosity" is, the easier it is to accelerate as in the case of being in the air, while the larger the "viscosity" is, the more difficult it is to accelerate as in the case of being in a highly viscous liquid. Further, the offset value of the force can be adjusted and set for adjusting the force for guiding the gripping means in the desired direction. These parameters can be managed and set according to the equipment / devices used.

Following i), the present invention includes ii) a step of pressing the gripped object to be transported against a predetermined measurement surface (for example, an operation as shown in FIG. 2). As long as the measurement surface has a certain flat surface on which the gripped object to be transported can be pressed, the place where the measurement surface is installed and the orientation of the surface (for example, an oblique surface, a vertical surface, etc.) are not restricted. However, it is preferable that the measuring surface is easily incorporated into a series of operations of the transport device including the gripping means. When the gripping means (and the transport device including the same) is a general robot hand or the like, the measurement surface shall have a table (stage) capable of vertically and downwardly pressing the gripped object to be transported. The height and size of the stage can be appropriately set according to the size of the object to be transported and the operation of the robot hand. It is known that the harder the measurement surface, the higher the accuracy of the thickness measurement itself in this case. In order to alleviate the degree of contact of the gripping means, it is preferable that a soft object such as a sponge or resin is installed on the outermost surface of the measurement surface. The material used for the surface can be appropriately selected.

Then, following this ii), as described in iii) above, when the gripped object is pressed against such a measurement surface, compliance control according to the contact force acts on the gripping means. As a result, the operation of the gripping means is stopped for a certain period of time. The downtime is as described above. Then, the displacement value of the gripping means in that case is measured. Here, the displacement value is a displacement value in the vertical direction (thickness direction of the object to be transported) with respect to the measurement surface, and is a reference for measuring the displacement value measured when the object to be transported is not gripped as described later. If they are the same, the displacement value of the tip portion of the gripping means or the other portion may be used as a reference. Such a displacement value is measured based on, for example, an encoder value of each axis (joint) confirmed from the controller. When the object to be transported is gripped, a difference occurs in the above-mentioned displacement value as compared with the displacement value when nothing is gripped. Therefore, in the present invention, the difference in the displacement value is the difference in the displacement value to be transported. Will be measured as the thickness of. In the method of the present invention, when determining or measuring this displacement value (including the reference value of displacement), the relationship with the above-mentioned parameters related to compliance control is confirmed and grasped in advance by a preliminary experiment or the like. It is preferable to keep it. That is, with respect to the speed and pressing pressure when the gripping means is pressed against a predetermined measurement surface, and the parameters related thereto, the displacement value in the thickness direction when the operation of the gripping means is stopped by the action of compliance control (reference). It is preferable to confirm the relationship with (including the value) in advance, and by confirming and grasping such a relationship in advance, the present invention has good reproducibility when incorporated into an actual process, device, or the like. You will be able to implement the method.

In the present invention, after the step iii) is performed, the thickness of the object to be transported is compared with the displacement value (= reference value) when the object to be transported is not gripped, as described in iv) above. Is measured. Then, if the thickness of each piece of the transported object can be grasped in advance, the number of gripped objects to be transported is calculated from the measured thickness value of the transported object. Since such an operation is also performed instantaneously in the controller, it is possible to automate the confirmation of the thickness and the number of sheets to be transported in the series of transport processes. In addition, based on the result of checking the thickness and the number of sheets by measuring the above displacement value, it is also possible to separately provide a mechanism for throwing the object to be transported into another transport path or discharging it as a defective product. Is.

After the thickness measurement of the object to be transported is performed in the process, the object to be transported is transported to the transfer destination, but the above-mentioned displacement value is measured not only in the middle of the process but also at the transfer destination. You can also do it. That is, it is also possible to perform the steps ii) and iii) on the measurement surface at the transport destination. In this case, it is possible to measure the gripped thickness and the number of sheets according to the displacement value measuring method described so far for the first one transported to the transport destination, and the second and subsequent ones are transported. For those, it is possible to measure the total thickness of the objects to be transported (laminated products) that are sequentially laminated at the transport destination according to the same displacement value measurement method. If the thickness of one sheet can be grasped in advance, the confirmation result of the number of laminated sheets can be obtained based on the measurement of the total thickness. Further, at the transport destination, it is possible to measure the thickness and the number of gripped objects each time they are transported without stacking the transported objects, or the transported objects are gripped. It is also possible to measure only the total thickness of the laminated material by pressing the gripping means against the laminated object to be transported in the absence state. In any case, it is necessary to set the parameters related to the compliance control in advance when the gripping means and the measuring surface come into contact with each other (pressing).

The destination may be separately provided with a means for releasing (releasing) the gripped object to be transported. For example, after the object to be transported is thrown into a line out of a series of processes, it may be manually operated or another device. It is also possible to collect the transported object by using the above. As a mechanism for releasing (releasing) the object to be transported in the gripping means, for example, pushing with a pin from the gripping means side, peeling with air, hooking with a nail or the like, or pinching and peeling by a person, etc. However, as described above, when the electrostatic chuck is used as the gripping means, it is preferable because the gripped object can be easily released (released) by turning on / off the voltage application. ..

The gripping means used in the method of the present invention and other devices / devices related to transportation may be provided with various sensors (for example, force sensor, thickness sensor, etc.), a camera, and the like. The method of the present invention utilizes force control by compliance control, and these sensors, cameras, etc. are not essential for measuring and confirming the thickness and number of objects to be transported, but they are installed. Therefore, it is possible to improve the accuracy of measurement.

Hereinafter, preferred embodiments of the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not construed as being limited thereto.

1. 1. Examination of gripping means (evaluation of adsorption force according to the configuration of electrostatic chuck)
First, the configuration (resin film, electrode layer) of the electrostatic adsorbent (electrostatic chuck) was changed for the gripping means using the electrostatic force, and the attractive force to various objects was evaluated. The production of an electrostatic chuck (manufacturing example) and its evaluation, and the evaluation of the attractive force based on the electrode width and pitch (experimental example) will be described separately.

[Manufacturing Example 1]
<Manufacturing of electrostatic chuck A (flat electrode)>
Double-sided Kapton (registered trademark) tape [Teraoka Seisakusho Co., Ltd., trade name: Kapton (registered trademark) double-sided tape 760H] was attached to one side of a copper foil (thickness: 18 μm) to be an electrode layer. Next, only the copper foil portion was used with a cutting plotter (Graphtec Corporation, trade name: FC2250-180VC), and as shown in FIG. 3, two electrodes [each electrode width 30 mm (length 60 mm), and electrode spacing (pitch). ) 2 mm] to form an electrode pattern and use it as an electrode sheet. Then, an insulator (Kinugawa Co., Ltd., trade name: Graform GF-5) as a base base material was attached to the surface of the electrode sheet opposite to the copper foil surface. After removing unnecessary copper foil, a soft polyvinyl chloride film which is a resin film on the copper foil surface side [volume resistivity: 1 × 10 ¹⁰ Ω · cm (measured by the method described later), tensile elastic modulus (Young's modulus) ): 20 to 30 MPa, thickness 100 μm] was attached using a laminator and a roller to obtain a bipolar laminated sheet in which the electrode layer (copper foil) was sandwiched between the insulator and the resin film. The outline of the electrode and the laminated structure of the electrostatic chuck A is shown in FIG.

A power supply device (a high voltage generator (± 2000V output), a power supply cable, and a power supply device consisting of a 24V power supply] (not shown) was attached to the laminated sheet thus produced to form an electrostatic chuck A.

<Evaluation of adsorptivity of electrostatic chuck>
A voltage of ± 2 kV is applied to the electrostatic chuck A, and four types of test pieces [copy paper (high quality paper, thickness: about 0.092 mm), polyester (PE) 100%) are placed on the resin film side as objects to be adsorbed. Cloth piece (thickness about 0.47 mm), 100% cotton cloth piece 1 (hereinafter, this is referred to as "cotton 1". Hard cloth with a handicraft pattern printed, thickness about 0.24 mm), cotton A 100% piece of cloth 2 (hereinafter, this is referred to as "cotton 2". A soft cloth for underwear, a thickness of about 0.32 mm) was placed and adsorbed. After hooking the hook of the push-pull gauge (trade name: Digital Force Gauge FGJN-5) manufactured by Nidec-Shimpo Co., Ltd., on the loop-shaped hook part (made of nylon) attached to the test piece in advance, push it. The pull gauge was pulled in the horizontal direction, and the measurement result was taken as the attraction force (unit: gf / cm ² ) for each test piece. The situation is shown in FIG. 5, and the results are shown in Table 1 below.

The volume resistivity of the soft polyvinyl chloride film in Production Example 1 was measured by the double ring electrode method (IEC60093, ASTM D257, JIS K6911, JIS K6271) and used in Production Examples 2 to 5 described later. The volume resistivity of each resin film was also measured by the same method.

[Manufacturing Example 2]
As the electrode layer, a comb-teeth-like electrode [width of each comb tooth (electrode width) 10 mm, electrode spacing (pitch) 2 mm] formed by meshing a pair of comb teeth on the same surface as shown in FIG. 4 was used. Except for the above, the electrostatic chuck B according to Production Example 2 was produced in the same manner as in Production Example 1, and its adsorptivity was evaluated in the same manner. The results are as shown in Table 1. The outline of the electrode of the electrostatic chuck B is shown in FIG.

[Manufacturing Example 3]
As the electrode layer, the comb-toothed electrode is the same as in Production Example 2, except that the width (electrode width) of each comb tooth is 10 mm and the electrode spacing (pitch) is 5 mm. The electrostatic chuck C according to Production Example 3 was produced, and its adsorptivity was evaluated in the same manner. The results are as shown in Table 1.

[Manufacturing Example 4]
As a resin film to be the adsorption surface of the object to be adsorbed, a polyimide film [Product name manufactured by Toray DuPont Co., Ltd .: Capton (registered trademark) H, volume resistance: 1 × 10 ¹⁷ Ω · cm (measured by the above method) , Tensile elasticity (Young rate): 3 × 10 ³ MPa, thickness 50 μm], and as an electrode layer, a flat plate-shaped bipolar electrode [electrode width 60 mm (length 110 mm)) similar to that in Production Example 1 and The electrostatic chuck D according to Production Example 4 was produced in the same manner as in Production Example 1 except that the electrode spacing (pitch) was 2 mm], and its adsorptivity was evaluated in the same manner. The results are shown in Table 1.

[Manufacturing Example 5]
As a resin film to be the adsorption surface of the object to be adsorbed, a polyimide film [Product name manufactured by Toray DuPont Co., Ltd .: Capton (registered trademark) H, volume resistance: 1 × 10 ¹⁷ Ω · cm (measured by the above method) , Tensile elasticity (Young rate): 3 × 10 ³ MPa, thickness 50 μm], and as an electrode layer, a comb-tooth-shaped bipolar electrode similar to that in Production Example 2 [width of each comb-tooth (electrode width) ) 0.7 mm, electrode spacing (pitch) 0.7 mm], the electrostatic chuck E according to Production Example 5 was produced in the same manner as in Production Example 1, and its adsorptivity was also produced in the same manner. Evaluation was performed. The results are shown in Table 1.

[Experimental Examples 1 to 12 (Measurement of adsorption force by electrode width)]
Except for using comb-toothed electrodes as in Production Example 2 as the electrode layer and fixing the spacing (pitch) of each electrode to 2 mm while changing the width (electrode width) of each comb-tooth to 1 mm to 30 mm, respectively. Made each of Experimental Examples 1 to 12 electrostatic chucks in the same manner as in Production Example 2, and evaluated their adsorptivity in the same manner. The results are as shown in Table 2. ^{The reason why the result of the adsorption force (gf / cm 2} ) was different from that of the production example 2 in the experimental example 10 performed using the electrode layer having the same electrode width and pitch as the production example 2 is as a reason. It is presumed that the temperature and humidity at the time of measurement have an effect because the experiment dates are different.

[Experimental Examples 13 to 17 (Measurement of adsorption force by electrode pitch)]
Except for using a comb-shaped electrode as in Production Example 2 as the electrode layer and fixing the width (electrode width) of each comb tooth to 10 mm and changing the electrode spacing (pitch) to 1 mm to 5 mm, respectively. , Each of the electrostatic chucks of Experimental Examples 13 to 17 was produced in the same manner as in Production Example 2, and the adsorptivity was evaluated in the same manner. The results are as shown in Table 3. In Experimental Example 14 performed using an electrode layer having the same electrode width and pitch as in ^{Production Example 2 and Experimental Example 10, the result of the adsorption force (gf / cm 2} ) is the result of Production Example 2 and Experimental Example 10. It is presumed that the reason for the difference from the case of is that the temperature and humidity at the time of measurement have an influence because the experiment dates are different.

2. Compliance control setting and cloth thickness (number of sheets) measurement using it (1) Compliance control setting (preliminary experiment)
[Device]
First, a preliminary experiment was conducted on the setting of the gripping means including the compliance control without gripping the cloth piece to be transported. The gripping means has the following configuration. That is, an electrostatic chuck (the same electrostatic chuck B as in Production Example 2) was used for the contact portion with the object to be transported. Then, this electrostatic chuck B was attached to the tip of a vertical articulated robot hand (VP-6242 manufactured by Denso Wave Incorporated) via an attachment to serve as a gripping means. As the measuring surface for pressing the gripping means, a metal table having a horizontal surface wider than the electrostatic chuck and the object to be transported (cloth piece) is used, and the horizontal surface (contact surface) is made of cushioning chloroprene rubber. A sheet (thickness 5 mm, hardness 25 ± 5 degrees, 25% compression load 50-80 kPa) was installed. A schematic diagram is shown in FIG.

[Outline of measurement method]
The measurement position (reference position) of the robot hand was the same in all tests. That is, it was as follows according to the coordinate axes of FIG. Regarding the coordinate axes, the point (x, y, z) = (0,0,0) indicates the center of the ground plane of the robot hand. With respect to z, the height is gradually lowered from 190 mm until it comes into contact with the measurement surface (table) and stops (if there is no cloth piece to be transported, it stops at around z = 185 mm), and z when stopped. The coordinates were set to be acquired as the height of the electrostatic chuck. These settings were specified on the measurement program stored in the controller of the robot hand, and the parameters were adjusted while checking the acquired z-coordinates. When creating the program, the programming language (PacScript) used by the robot hand used is used, and the outline of the program is as shown in a) to d) below.
a) Move the robot directly above the measurement position (z = 190, x, y, rx, ry, rz are the following values).
b) Enable the compliance control function.
c) Move the robot to the measurement position (z = 180) (actually, stop in the middle)
d) Get the z coordinate.
<Measurement coordinates>
x = 325.0272
y = 0
z = 180-190
rx = 179.8521 (rotation around the x-axis)
ry = 0.06496224 (Rotation around the y-axis)
rz = -67.59645 (rotation around the z-axis)

[Parameter adjustment]
The parameters for compliance control of the robot hand were set. The changed parameters are speed (robot operating speed, 1 to 100%), target control force (upper limit of control force applied to the measurement surface by the tip of the robot hand. No more than the set force is output. For example, this value is set. When it is made smaller, it operates according to a small external force applied to the robot hand from the outside.), Current limit value [Setting the torque value (current value) of the motor of each axis of the robot. 100% is the rating, and if this value is reduced, the torque value (current value) will decrease, the resistance force against the external force will be weakened, and the movement will change even if an external force is applied lightly. ]. These initial values are values that are considered to be good for hand adjustment, with a control force of 4 Newton (N) and a current limit value of 10% per joint (axis) (10% for all 6 axes). The operating speed was set to 10%. These parameters were specified in the measurement program stored in the controller of the robot hand as described above.
Specifically, the position where the robot stops when the electrostatic chuck is pressed against the measurement surface (table) by changing the above three parameters while the electrostatic chuck does not grip anything [z of the electrostatic chuck The change in the displacement value of the axis (hereinafter, may be simply referred to as "displacement value of the z-axis")] was measured. Regarding the measured values, those acquired in the controller program were output to an external personal computer (PC) and read, and based on the measured values, analysis such as calculation of average values and errors was also performed on the PC. The number of repetitions for each measured value is N = 10.

[Test Example 1] Confirmation of change in stop position (control force is fixed at 4N) according to current limit value and operating speed Current limit value (curlm) is set to 0%, 5%, 10%, 15%, 20%, Change to 25% and 30%, respectively, and the operating speed [speed (%); horizontal axis] at each current limit value is 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70. The z-axis displacement values [z (mm); vertical axis] at%, 80%, and 90% were measured. As for the current limit value, the 6 axes were set to the same value in all cases including Test Example 2 and later. The results are shown in FIG. 7 (the error bars in the figure represent the average value of 3σ). In FIG. 7, in order to avoid overlapping of the plots, the values of the operating speeds shown on the horizontal axis are intentionally shifted and plotted. For example, when the speed is 0%, the plots are divided into speeds of -1% to + 3% so that the plots do not overlap. The same applies to the other speeds of FIG. 7, and the same applies to the following FIGS. 8 to 12 and 14.
Then, from the result of FIG. 7, for the robot hand used this time, if the current limit value is 10% and the operating speed is 50% or less, or if the current limit value is 15% or more regardless of the operating speed. Measurement results with small error were obtained. When the current limit value was 0 to 5%, the robot could not operate sufficiently.

[Test Example 2] Confirmation of change in stop position according to control force and operating speed (current limit value is fixed at 10% for each of 6 axes) Control force (force) is set to 1N, 2N, 3N, 4N and 5N, respectively. The operating speed [speed (%); horizontal axis] at each control force is changed to 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 90%. The displacement value of the z-axis [z (mm); vertical axis] was measured. The results are shown in FIG. 8 (the error bars in the figure represent the average value of 3σ).
From the results of FIG. 8, for the robot hand used this time, if the operating speed is 50% or less, the measured value and the measurement result with a small error can be obtained in the range of the control force of 1 to 5N, and the operating speed is higher than that. The larger the value, the larger the error tends to be.

[Test Example 3] Confirmation of change in stop position (operating speed is fixed at 10%) according to current limit value and operating speed Current limit value (curlm) is set to 0%, 5%, 10%, 15%, 20%. , 25% and 30%, respectively, and the displacement value of the z-axis [z (mm)) when the control force [force (N); horizontal axis] at each current limit value is 1N, 2N, 3N, 4N and 5N. ; Vertical axis] was measured. The results are shown in FIG. 9 (the error bars in the figure represent the average value of 3σ).
From the results of FIG. 9, for the robot hand used this time, if the current limit value is 10% or more, the measured value and the measurement result with a small error can be obtained between the control force of 1 to 5N. Similar to Test Example 1, when the current limit value was 5% or less, the robot could hardly be moved.

[Test Example 4] Confirmation of change in stop position (current limit value is fixed at 10% for each of 6 axes) according to operating speed and control force Operating speed (speed) is set to 0%, 10%, 20%, 30%. , 40%, 50%, 60%, 70%, 80% and 90%, respectively, when the control force [force (N); horizontal axis] at each operating speed is 1N, 2N, 3N, 4N and 5N. The displacement value of the z-axis [z (mm); vertical axis] was measured. The results are shown in FIG. 10 (the error bars in the figure represent the average value of 3σ).
From the results of FIG. 10, for the robot hand used this time, if the operating speed was 50% or less, the measured values and the measurement results with a small error were obtained between the control forces of 1 to 5N. Moreover, the larger the control force, the smaller the error.

[Test Example 5] Confirmation of change in stop position (operating speed is fixed at 10%) according to control force and current limit value Control force (force) is changed to 1N, 2N, 3N, 4N and 5N, respectively. The z-axis when the current limit value [curlm (%); horizontal axis] in the control force is 0%, 5%, 10%, 15%, 20%, 25% and 30% (all 6 axes have the same set value). The displacement value [z (mm); vertical axis] was measured. The results are shown in FIG. 11 (the error bars in the figure represent the average value of 3σ).
From the results of FIG. 11, for the robot hand used this time, if the current limit value is 10% or more, the measured value and the measurement result with a small error can be obtained between the control force of 1 to 5N. Similar to Test Example 1, when the current limit value was 5% or less, the robot could hardly be moved.

[Test Example 6] Confirmation of change in stop position (control force is fixed at 4N) according to operating speed and current limit value Operating speed (speed) is set to 0%, 10%, 20%, 30%, 40%, 50 %, 60%, 70%, 80% and 90%, respectively, and the current limit value [curlm (%); horizontal axis] at each operating speed is 0%, 5%, 10%, 15%, 20%, The displacement value [z (mm); vertical axis] of the z-axis at 25% and 30% (the same set value for all 6 axes) was measured. The results are shown in FIG. 12 (the error bars in the figure represent the average value of 3σ).
From the results of FIG. 12, for the robot hand used this time, the operating speed is 60% or less when the current limit value is 10%, or the operating speed is 0 to 90% when the current limit value is 15% or more. In the range of, the measured values and the measurement results with small error were obtained.

[Test Example 7] Confirmation of change in stop position (control force is fixed at 4N, operating speed is fixed at 10%) according to the current limit value when the object to be transported is gripped. A piece of cloth (cloth in Table 4) is used as the object to be transported. Number 1; Made of cotton, thickness 0.560 mm, approx. 100 mm x 85 mm), change this to 0, 1, 2 and 3 respectively, and the current limit value for each number (denoted as "number") [Curlm (%); horizontal axis] is 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15 The displacement value [z (mm); vertical axis] of the z-axis at%, 16%, 18%, 20%, 25% and 30% (all 6 axes have the same set value) was measured. The results are shown in FIG. 13 (the error bars in the figure represent the average value of 3σ).
From the results of FIG. 13, it was found that in the actual measurement of the thickness of the cloth piece, if the current limit value is 10%, the difference between the thickness and the number of sheets can be detected.

Based on the results of Test Examples 1 to 7, in order to confirm the thickness and the number of cloths to be transported, the robot hand used this time has an operating speed of 50% or less and a current limit value of 10. % Or more (10% or more for each of the 6 axes), the thickness of the cloth for which the measurement error (average value 3σ) wants to determine the number of sheets within the range of control force 1 to 5N (0.195 to 0.771 in this data) It is 10% or less of mm), and the number of cloths can be counted accurately. That is, even if a gripping means having a compliance control mechanism different from the above is used, at least the operating speed, control force, and current limit value (or those) can be obtained by carrying out such a preliminary experiment. If the measurement error is 50% or less of the thickness of the object to be transported (cloth), the number of cloths can be confirmed accurately by other robots. If so, the method of the present invention can be carried out in the same manner.

[Test Example 8]
Based on the results of Test Examples 1 to 7, the operating speed of the gripping means is set to 10%, the control force is set to 4N, and the current limit value is set to 10% (10% for each of the 6 axes), and then the electrostatic chuck portion. A piece of cloth (one piece, two pieces, three pieces, written as "number"; horizontal axis) is attracted to the surface, and similarly pressed against the measurement surface, the displacement value of the z-axis (thickness of the piece of cloth, "number"). Notated as "thickness (mm)"; vertical axis) was measured. The cloth pieces used are those of cloth numbers 1 to 9 shown in Table 4. The reference value was a displacement value on the z-axis when the cloth was not gripped (repeated number of measured values N = 50). The value obtained by measuring the thickness of one piece of cloth with a micrometer is also described (the number of repetitions of the measured value N = 1). The results are shown in Table 4 and FIG.
From the results of Table 4 and FIG. 14, if the gripping means is equipped with the compliance control this time, the difference in thickness depending on the number of sheets from a relatively thin cloth of about 0.2 mm to a relatively thick cloth of about 1 mm. Was detected, and it was found that the number of sheets could be detected if the thickness could be measured.

1 ... Electrostatic chuck, 2 ... Robot hand, 3 ... Gripping means, 4 ... Object to be transported, 5 ... Controller, 6 ... Table (measurement surface), 7 ... Rubber sheet, 8 ... Attachment, a ... Electrode layer (positive) Electrode or negative electrode), b ... Resin film, b'... Insulator, c / c'... Electrostatic adsorbent (laminated sheet), d ... Adsorbed object, e ... Push-pull gauge

Claims (8)

This is a method of measuring the thickness of a sheet-shaped object to be transported while grasping the object to be transported.
A step of gripping the object to be transported using a gripping means provided with a compliance control mechanism, a step of pressing the gripped object to be transported against a predetermined measurement surface, and a step of pressing the gripped object against a predetermined measurement surface, and the gripping means by the compliance control mechanism when pressed. It has a process of measuring the displacement value in the thickness direction when the operation of
A method for measuring the thickness of a sheet-shaped object to be transported, which comprises measuring the thickness of a gripped object to be transported by comparing the measured displacement value with a preset reference value. The reference value is a displacement value when the gripping means is pressed against a predetermined measurement surface without gripping the object to be transported and the operation of the gripping means is stopped by the compliance control mechanism when the gripping means is pressed. The method for measuring the thickness of a sheet-shaped object to be transported according to claim 1, wherein the thickness is obtained by the above method. In advance, the speed and / or the pressing pressure when the gripping means is pressed against the predetermined measurement surface, parameters related thereto, and the displacement value in the thickness direction when the operation of the gripping means is stopped by the compliance control mechanism. The method for measuring the thickness of a sheet-shaped object to be transported according to claim 1 or 2, wherein the thickness of the object to be transported is measured after confirming the relationship with the object in advance. The method for measuring the thickness of a sheet-shaped object to be transported according to any one of claims 1 to 3, wherein the gripping of the object to be transported is by electrostatic adsorption. The thickness of the sheet-shaped object to be conveyed according to any one of claims 1 to 4, wherein the gripping means is a robot hand provided with an electrostatic chuck that attracts and grips the object to be conveyed by electrostatic attraction. Measuring method. The electrostatic chuck applies a voltage to the electrode layer and a laminated sheet in which an insulator having a thickness of 20 to 200 μm, an electrode layer having a thickness of 1 to 20 μm, and a resin film having a thickness of 20 to 200 μm are sequentially laminated. A power supply device is provided, and at least the tensile elasticity of the resin film is 1 MPa or more and less than 100 MPa, the volume resistance thereof is 1 × 10 ¹⁰ to 10 ¹³ Ω · cm, and the electrode layer is a positive electrode and It consists of a bipolar electrode having a negative electrode, and the resin film is used as an adsorption surface to adsorb an object to be transported as an object to be adsorbed by an electrostatic adsorption force generated by applying a voltage to the electrode layer. The method for measuring the thickness of a sheet-shaped object to be transported according to claim 5. It is a method of grasping and transporting a sheet-shaped object to be transported.
At the transport source, a step of grasping the object to be transported by using the method according to any one of claims 1 to 6 and measuring the thickness of the object to be transported while gripping the object to be transported, and a step of measuring the thickness of the object to be transported, the thickness of the object to be transported is measured. A method for transporting a sheet-shaped object to be transported, which comprises a step of transporting to a transport destination. The step of pressing the gripped object to be transported against the mounting surface or the upper surface of the stacked objects to be transported at the transfer destination, and the displacement when the operation of the gripping means is stopped by the compliance control mechanism when the pressed object is pressed. Has a process to measure the value
The sheet shape according to claim 7, wherein the thickness of the gripped object to be transported or the total thickness of the object to be transported laminated at the transfer destination is measured based on the measured displacement value. Method of transporting the object to be transported.

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