JP2011136397A - Brush condition determination device and determination method of conductive rotary brush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brush condition determination device and determination method for comparatively simply, easily and quantitatively determining the flexibility of a rotary brush. <P>SOLUTION: This brush condition determination device includes a robot arm 3 and a robot hand 4 for moving the rotary brush to a measuring surface Wf of a workpiece W for measurement, while rotating the rotary brush, a motor 5 and a control unit 8 for switching rotating speed of the rotary brush among a plurality of different brush rotating speeds, a power source device for applying voltage between the rotary brush and a surface of the workpiece W for measurement, and a voltmeter for detecting a voltage change between both of the rotary brush and the measuring surface Wf of the workpiece W when the rotary brush is in contact with the measuring surface Wf of the workpiece W. A voltage change starting position of the rotary brush when the voltage change is generated after the rotary brush starts to contact the measuring surface Wf of the workpiece W and a voltage stabilizing position of the rotary brush when the voltage is substantially stabilized after the rotary brush sufficiently contacts by the measuring surface Wf are recorded for each of the plurality of different brush rotating speeds, based on an output value of the voltmeter. Flexibility of the rotary brush is determined based on the recorded data and a flexibility evaluation value fixed in advance. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus and a method for determining a brush state of a rotating brush used for finishing a surface to be processed, particularly a rotating brush having conductivity.

  In the present specification, the term “conductive” for a rotating brush does not necessarily mean that all of the many bristle materials constituting the brush have conductivity, and is in a rotating state in contact with the surface to be treated. It is sufficient that electrical conduction is obtained between the rotating brush and the surface to be processed. Therefore, the configuration of the brush may be, for example, a configuration in which an appropriate number of conductive hair materials are mixed in a large number of non-conductive hair materials.

  In this specification, “surface finishing operation” means a normal cleaning operation that simply removes, for example, dust, rust, burrs, paint film pieces, welding slag, or other foreign matters adhered or fixed to the surface. In addition, a polishing (polishing) operation with improvement of the properties of the surface itself such as polishing (polishing) of the surface is also included.

  As a method for finishing a surface to be processed, a method for finishing a surface by moving a rotating brush along a predetermined locus while contacting the surface to be processed is generally well known. A finishing robot that automatically performs such finishing work is also known.

  As the bristle material constituting the rotating brush used in such finishing work, various bristle materials such as metal bristle materials such as brass and steel, or bristle materials based on wear-resistant synthetic resins such as nylon, etc. From the types, suitable ones are selected according to the material of the surface to be treated, the type of finishing work, and the like.

  In such a finishing operation using a rotating brush, if the tip of the rotating brush (that is, the tip of the hair material) wears with the progress of the finishing operation, the number of brush hair materials that come into contact with the surface to be processed decreases, and the processing is completed. There is a problem that the area to be reduced is reduced, and it is difficult to obtain sufficient finishing quality.

  For example, in Patent Document 1, a brush having conductivity (conductive brush) is used as a rotating brush, and the amount of brush wear is corrected by utilizing the fact that the rotating brush is conductive. The configuration described above is disclosed. In this prior art, a conductive reference body is connected to the conductive brush through a conductor to enable switching between the two, and when the tip of the conductive brush is worn to some extent as the polishing operation proceeds, the conductive brush Is lowered and brought into contact with the reference surface of the conductive reference body, this contact is detected by switching, the contact position is stored in the memory, and the cutting depth of the brush with respect to the surface to be processed (that is, using this contact position as a reference) The amount of wear of the brush is corrected by moving the rotating brush up and down to a position where the pressing force is appropriate.

Japanese Patent Laid-Open No. 62-188666

  By the way, when finishing a surface to be processed using a rotating brush, generally, there are various conditions such as the material and wire diameter of the bristle material, the shape and basic size of the brush, and the usage conditions such as the rotation speed of the brush. If it is the same, while the brush is new and the bristle material is highly flexible, the brush spreads by rotation (especially, expansion in the diametrical direction) is large, and a finishable width (area) can be secured. When used over a period of time, the tip is not only worn, but it is difficult to spread the brush during rotation, and the finishable width is reduced. This is considered to be due to a decrease in the brush spreading function due to the centrifugal force generated by the rotation as a result of the decrease in the flexibility of the brush (that is, the flexibility of the bristle material) with use.

Therefore, in order to stably obtain a sufficient finishing quality, not only the wear state of the rotating brush (in other words, the diameter size of the rotating brush at that time) but also the flexibility of the rotating brush itself is grasped. It is important to plan finishing work.
However, conventionally, as described above, when the brush is worn to some extent, correction of the amount of wear of the brush is intended, but there is no intention to properly grasp the flexibility of the brush itself. The actual situation is that the brush life due to loss of flexibility is managed based on the expected life left to the judgment of the skilled worker by visual inspection.

  In view of the above, the present invention has as its basic object to make it possible to quantitatively determine the flexibility of a rotating brush in a relatively simple and easy manner when performing a finishing operation on the surface to be processed using the rotating brush. It was made.

  The inventor of the present application has been diligently engaged in research and development to achieve the above object, and when the same rotating brush is rotated at a plurality of different rotating speeds, the difference in how the brush spreads due to the difference in rotating speed is determined by the flexibility of the brush. We found that it depends heavily on sex. And by paying attention to this point, the present invention has been reached in which the flexibility of the rotating brush can be determined relatively easily and easily.

  A brush state determination device according to the present invention is a brush state determination device for determining the brush state of a conductive rotary brush, and moves the rotary brush so as to be able to come into contact with and separate from the surface of the workpiece for measurement. Brush moving means, rotational speed switching means for switching the rotational speed of the rotary brush between a plurality of different brush rotational speeds, a power supply device for applying a voltage between the rotary brush and the measurement work surface, and Based on the output value of the voltage detecting means for detecting a voltage change between the rotating brush and the measuring work surface when the rotating brush comes into contact with the measuring work surface, the rotating brush starts to come into contact with the measuring work surface. The voltage change start position of the rotating brush when the change occurs, and when the rotating brush is sufficiently in contact with the measurement work surface and the voltage is substantially stabilized Based on the recording means for recording the voltage stabilization position of the rolling brush for each of the plurality of different brush rotation speeds, the recording data of the recording means and a predetermined flexibility evaluation value, And determining means for determining sex.

  In this apparatus, for each case when rotating at a plurality of different brush rotation speeds, the position of the rotating brush (voltage change) when the rotating brush starts to contact the measurement work surface and the applied voltage changes between them. Start position) and the position (voltage stabilization position) of the rotating brush when the applied voltage is stabilized when the rotating brush is sufficiently in contact with the surface of the workpiece for measurement. The flexibility of the rotating brush is determined based on the flexibility evaluation value.

  The brush state determination method according to the present invention is a brush state determination method for determining the brush state of a conductive rotary brush, and is capable of coming into contact with and separating from the measurement work surface while rotating the rotary brush. When the rotating brush comes into contact with the measurement work surface in the brush moving step to be moved, the rotation speed switching step for switching the rotation speed of the rotating brush between a plurality of different brush rotating speeds, and the brush moving step. A voltage detection step for detecting a change in the voltage applied between the two and a voltage change caused when the rotating brush starts to contact the surface of the workpiece for measurement based on the output value obtained in the voltage detection step. The voltage change starting position of the rotating brush and the voltage stabilizing position of the rotating brush when the rotating brush is sufficiently in contact with the measurement workpiece surface and the voltage is substantially stabilized. Determining the flexibility of the rotating brush based on a recording process for recording each of the plurality of different brush rotation speeds, recording data obtained in the recording process, and a predetermined flexibility evaluation value And a process.

  In this method, for each case when rotating at a plurality of different brush rotation speeds, the position of the rotating brush (voltage change) when the rotating brush starts to contact the surface of the measurement workpiece and the applied voltage changes between them. Start position) and the position (voltage stabilization position) of the rotating brush when the applied voltage is stabilized when the rotating brush is sufficiently in contact with the surface of the workpiece for measurement, and this recorded data and predetermined The flexibility of the rotating brush is determined based on the flexibility evaluation value.

In the above case, the difference between the voltage change start position and the voltage stabilization position at the first rotation speed among the plurality of different brush rotation speeds, and the voltage at the second rotation speed different from the first rotation speed. Based on the difference between the change start position and the voltage stabilization position, the flexibility of the rotating brush can be determined.
In this configuration, by comparing or comparing the difference between the voltage change start position and the voltage stabilization position at each of the first and second rotation speeds, the difference in how the brush spreads due to the difference in rotation speed is evaluated, The flexibility of the brush is determined.

Alternatively, in the above case, a difference between a voltage change start position at a first rotation speed among the plurality of different brush rotation speeds and a voltage change start position at a second rotation speed different from the first rotation speed. Based on the above, the flexibility of the rotating brush can be determined.
In this configuration, the voltage change start positions at the first and second rotational speeds are compared, and the difference in the brush spreading method due to the difference in the rotational speed is evaluated based on the difference, thereby determining the flexibility of the brush. .

Further, in the above case, a voltage stabilization position at a first rotation speed among the plurality of different brush rotation speeds and a voltage stabilization position at a second rotation speed different from the first rotation speed. Based on the difference, the flexibility of the rotating brush can also be determined.
In this configuration, the voltage stabilization positions at the first and second rotation speeds are compared, the difference in the brush spreading method due to the difference in the rotation speed is evaluated based on the difference, and the flexibility of the brush is determined. .

  A brush state determination apparatus according to another invention of the present application is a brush state determination apparatus for determining a brush state of a conductive rotary brush, and is in contact with a measurement work surface while rotating the rotary brush. A voltage is applied between the brush moving means for releasably moving, the rotation speed switching means for switching the rotation speed of the rotary brush between a plurality of different brush rotation speeds, and the rotary brush and the measurement work surface. The rotating brush is moved to a predetermined first brush position by the power supply device, voltage detecting means for detecting a voltage change between the rotating brush and the measuring work surface when the rotating brush contacts the measuring work surface. Sometimes the voltage detection means detects the first voltage value and the rotating brush has moved to a second brush position that is a predetermined distance away from the first brush position. Recording means for recording the second voltage value detected by the voltage detecting means for each of the plurality of different brush rotation speeds, recording data of the recording means, and a predetermined flexibility evaluation value. And determining means for determining the flexibility of the rotating brush.

  In this apparatus, for each case of rotation at a plurality of different brush rotation speeds, an applied voltage value (first voltage) between the rotating brush and the measurement work surface when the rotary brush moves to a predetermined first brush position. Value) and an applied voltage value (second voltage value) between the rotating brush and the measurement work surface when the rotary brush moves to a second brush position separated from the first brush position by a predetermined amount. The flexibility of the rotating brush is determined based on the recording data and a predetermined flexibility evaluation value.

  Furthermore, a brush state determination method according to another invention of the present application is a brush state determination method for determining a brush state of a conductive rotary brush, and is in contact with a measurement work surface while rotating the rotary brush. The rotating brush contacts the measurement work surface in a brush moving step for moving the brush separately, a rotation speed switching step for switching the rotation speed of the rotating brush between a plurality of different brush rotation speeds, and the brush moving step. A voltage detecting step for detecting a change in the voltage applied between the two and a first voltage value detected when the rotating brush moves to a predetermined first brush position in the brush moving step; A second voltage value detected when the rotating brush moves to a second brush position separated by a predetermined amount from the first brush position, and a plurality of different brush rotation speeds. And a determination step for determining the flexibility of the rotating brush on the basis of the recording data obtained in the recording step and a predetermined flexibility evaluation value. It is what.

  In this method, for each case of rotation at a plurality of different brush rotation speeds, an applied voltage value (first voltage) between the rotating brush and the measurement work surface when it moves to a predetermined first brush position. Value) and an applied voltage value (second voltage value) between the rotating brush and the measurement work surface when the rotary brush moves to a second brush position separated from the first brush position by a predetermined amount. The flexibility of the rotating brush is determined based on the recording data and a predetermined flexibility evaluation value.

In these other invention apparatuses and invention methods, both the first brush position and the second brush position are the voltage change of the rotary brush when the voltage change occurs when the rotary brush starts to contact the measurement work surface. It is preferable to select between the start position and the voltage stabilization position of the rotating brush when the rotating brush is sufficiently in contact with the measurement work surface and the voltage is substantially stabilized.
In this configuration, since both the first brush position and the second brush position are selected between the position where the voltage change is started and the position where the voltage is substantially stabilized, the first voltage value at the first brush position is selected. And the second voltage value at the second brush position can be expected to be larger, and the accuracy of the brush flexibility determination can be improved.

  According to the present invention, when determining the brush state of a rotating brush used for finishing the surface to be processed, particularly a rotating brush having conductivity, each case when rotating at a plurality of different brush rotation speeds. The position of the rotating brush (voltage change start position) when the applied voltage changes between the rotating brush and the surface of the measuring work, and the rotating brush is more in contact with the measuring work surface. Since the position of the rotating brush when the applied voltage is stabilized (voltage stabilization position) is recorded, and the flexibility of the rotating brush is determined based on the recording data predetermined flexibility evaluation value, The difference in how the brush spreads due to the difference in rotation speed can be quantitatively evaluated, and the flexibility of the brush can be determined based on the quantitative data. That is, the flexibility of the rotating brush can be quantitatively determined easily and easily as compared with the conventional technique that relies exclusively on the judgment of a skilled worker.

  Further, according to another invention of the present application, when a brush state is determined for a rotating brush used for finishing the surface to be processed, particularly a rotating brush having conductivity, rotation at a plurality of different brush rotation speeds. In each case, the applied voltage value (first voltage value) between the rotating brush and the measurement work surface when the rotating brush moves to a predetermined first brush position, and the rotating brush is in the first brush position. An applied voltage value (second voltage value) with the measurement work surface when moving to a second brush position separated by a predetermined amount is recorded, and based on this recorded data and a predetermined flexibility evaluation value Therefore, it is possible to quantitatively evaluate the difference in how the brush spreads due to the difference in rotation speed and determine the flexibility of the brush based on quantitative data. Kill. That is, the flexibility of the rotating brush can be quantitatively determined easily and easily as compared with the conventional technique that relies exclusively on the judgment of a skilled worker.

It is a block diagram which shows the outline of the finishing robot which concerns on embodiment of this invention. It is a block diagram which shows the outline of the electric circuit for brush state determination attached to the said finishing robot. It is a graph which shows an example of the change of the output voltage of the constant current power supply with which the said electric circuit was equipped. It is a graph which shows typically change of an output voltage when a brush is easy to spread by rotation. It is a graph which shows typically change of an output voltage when a brush is hard to spread by rotation. It is a flowchart for demonstrating the brush state determination method of the rotating brush with which the said finishing robot was equipped. It is a graph of the change of the output voltage with respect to the operating distance of a brush which shows an example of the brush state determination according to this invention about the case of the new brush of a carbon steel hair material. It is a graph of the change of the output voltage with respect to the operating distance of a brush which shows an example of the brush state determination according to this invention about the case of the brush after use of a carbon steel bristle material. It is a graph of the change of the output voltage with respect to the operating distance of a brush which shows an example of the brush state determination according to this invention about the case of the new brush of a stainless steel bristle material. It is a graph of the change of the output voltage with respect to the operating distance of a brush which shows an example of the brush state determination according to this invention about the case of the brush after use of a stainless steel bristle material.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a configuration diagram schematically showing an outline of a finishing robot according to the present embodiment. As shown in this figure, the finishing robot 1 includes, for example, a base portion 2 fixed at a predetermined installation location, an arm portion 3 (robot arm) having a base end supported on the base portion 2, and the arm. A hand unit 4 (robot hand) held on the terminal side of the unit 3. The robot arm 3 is more preferably an articulated arm.

  The finishing robot 1 uses a rotating brush 6 for finishing the surface to be processed, and the rotating brush 6 rotates around the axis L6 of the brush shaft 6s. The brush shaft 6s is integrally coupled to a rotation shaft (motor shaft: not shown) of the motor 5 as a rotation drive source so that the axis lines L5 and L6 coincide with each other. To be rotated. The motor 5 is held on the terminal side of the robot hand 4.

  The robot arm 3 and the robot hand 4 move the rotating brush 6 along, for example, a predetermined trajectory taught in advance while maintaining a predetermined contact state with the surface to be processed at the time of finishing work. The motor 5 is connected to the control unit 8 of the finishing robot 1 so as to be able to send and receive signals, and the number of rotations is controlled to change according to a control signal from the control unit 8. The control unit 8 and the motor 5 constitute “rotational speed switching means” for switching the rotational speed of the rotary brush 6 between a plurality of different brush rotational speeds.

  The control unit 8 outputs a control signal to a drive unit (not shown) of the robot arm 3 and the robot hand 4 so as to control the moving operation of the rotating brush 6 by the robot arm 3 and the robot hand 4. . The robot arm 3, the robot hand 4, and the driving unit thereof constitute “brush moving means” for moving the rotating brush 6 so as to be able to contact and separate from the measurement work surface Wf (described later). The control unit 8 is configured with, for example, a microcomputer as a main part.

  In the present embodiment, the rotary brush 6 has conductivity, and the brush state can be determined using this conductivity. Specifically, the rotating brush 6 is made of, for example, a steel bristle material, and all the bristle materials are conductors. Note that not all of the bristle material constituting the brush 6 needs to have conductivity, and electrical conduction is obtained between the rotating brush 6 that is in contact with the surface to be processed and is in a rotating state and the surface to be processed. If necessary, the configuration of the brush 6 may be, for example, a configuration in which an appropriate number of conductive hair materials are mixed in a large number of non-conductive hair materials, as described above. .

In the present embodiment, in order to determine the brush state of the rotating brush 6 (specifically, the flexibility of the brush), a measurement work W is prepared. As shown in FIG. And an electric circuit 10 for applying a voltage between the rotating brush 6 and the rotating brush 6.
The measurement workpiece W is preferably formed of a conductor such as a rectangular parallelepiped metal, and is disposed in a state where one surface (measurement surface) Wf faces the rotating brush 6 side. When the determination of the brush state of the rotating brush 6 is performed, the rotating brush 6 is moved so as to come into contact with and separate from the workpiece measurement surface Wf while rotating by driving the robot arm 3 and the robot hand 4.

  In the initial state before the brush state determination test, the rotary brush 6 has a position of the brush shaft 6s (that is, a position of the motor axis L5 and the brush axis L6) separated from the workpiece measurement surface Wf by a predetermined distance d (see FIG. 2). The initial position is set. This initial position is selected within a range in which the bristle tip of the brush 6 does not come into contact with the workpiece measurement surface Wf even when the rotary brush 6 rotates at the maximum rotation speed as the test speed. The position of the rotating brush 6 can be represented by, for example, an operating distance from this initial position. Note that the position of the rotating brush 6 may be represented by a distance from the workpiece measurement surface Wf.

The electric circuit 10 is connected between the measurement workpiece W and the metal casing of the motor 5, and the rotating brush 6 comes into contact with the workpiece measurement surface Wf so that the two are electrically connected to each other. 10 closes.
The electric circuit 10 is provided with a power supply device 11, and a voltmeter 12 as a voltage detecting means is connected in parallel with the power supply device 11, and the power supply device 11 connects the rotating brush 6 and the measurement work W to each other. The voltage applied between them (ie, the change in voltage) can be detected by the voltmeter 12.

More preferably, the power supply device 11 is a so-called constant current power supply configured to flow a constant current through the circuit when the circuit is closed. In the present embodiment, for example, a constant current power supply having an output voltage of 15 volts (V) and an output current setting value of 0.1 ampere (A) is used.
Therefore, in a state where the rotary brush 6 is separated from the measurement surface Wf of the measurement workpiece W and the circuit 10 is open, the detection value of the voltmeter 12 is maintained at the maximum value of 15 volts. When the circuit 10 is completely closed by sufficiently contacting the measurement surface Wf of the measurement workpiece W, the detection value of the voltmeter 12 is greatly reduced so that a constant current of about 0.1 ampere flows through the circuit 10. It has become.

  FIG. 3 is a graph showing an example of a change in the output voltage of the constant current power supply 11 (that is, a change in the detected value of the voltmeter 12), where the vertical axis represents the output voltage (V) and the horizontal axis represents the rotation brush 6. It represents the operating distance (mm) from the initial position. In this graph, the rotating brush 6 is not in contact with the workpiece measurement surface Wf until the operating distance is Da, and the output voltage of the constant current power supply 11 is maintained at the maximum value of 15 volts. When the operating distance of the rotating brush 6 reaches Da, the rotating brush 6 starts to contact the workpiece measurement surface Wf, the output voltage starts to drop abruptly, and the moving operation of the rotating brush 6 proceeds slightly (operating distance Db). The output voltage greatly drops as the process proceeds to. Thereafter, as the moving operation of the rotating brush 6 further proceeds, the output voltage gradually decreases, and the rotating brush 6 is moved to the extent that complete conduction between the rotating brush 6 and the workpiece measurement surface Wf is obtained. When fully contacting the measurement surface Wf (operating distance Dc), the electric circuit 10 is completely closed, a constant current of about 0.1 amperes flows through the circuit 10, and the output voltage is stabilized at about 1 volt. .

  At this time, the process from when the rotating brush 6 starts to contact the measuring surface Wf of the measuring workpiece W until the electric circuit 10 is completely closed is determined by the material and wire diameter of the rotating brush 6 and the brush 6. If the conditions such as the shape and the basic size are the same, they are greatly influenced by the flexibility and the rotation speed of the rotating brush 6.

  That is, when the conditions such as the bristle material, the wire diameter, the shape and the basic size of the brush 6 are the same, and the rotational speed of the brush 6 is the same, generally, the flexibility of the brush 6 is high. In this case, since the brush is easily spread by the centrifugal force generated by the rotation, the rotary brush 6 starts to contact the workpiece measurement surface Wf earlier (the operation distance Da becomes shorter). In this case, for example, as schematically shown in FIG. 4, the voltage drop until the operating distance Dc of the rotating brush 6 until the complete conduction between the rotating brush 6 and the workpiece measurement surface Wf is obtained. The gradient tends to be relatively gentle.

  On the other hand, when the flexibility of the brush 6 is low, generally, the brush is difficult to spread during rotation, so that the rotation brush 6 starts to come into contact with the workpiece measurement surface Wf (the operation distance Da becomes smaller). Longer). Therefore, in this case, if the operating distance Dc of the rotating brush 6 until the complete continuity between the rotating brush 6 and the workpiece measurement surface Wf is obtained is approximately the same as that when the flexibility is high, for example, FIG. As schematically shown in FIG. 5, the slope of the voltage drop tends to be relatively steep.

  In addition, when the conditions such as the material of the bristle material, the wire diameter, the shape and the basic size of the brush 6 are the same, and the flexibility of the brush 6 is the same, generally when the brush rotation speed is high. Since the brush tends to spread during rotation, the rotary brush 6 starts to contact the workpiece measurement surface Wf earlier (the operation distance Da becomes shorter). In this case, similar to the case where the flexibility of the brush 6 is high, for example, as shown schematically in FIG. 4, generally, until complete conduction between the rotating brush 6 and the workpiece measurement surface Wf is obtained. The gradient of the voltage drop up to the operating distance Dc of the rotating brush 6 is relatively gentle.

  On the other hand, when the brush rotation speed is low, generally, the brush is difficult to spread during rotation, so that the rotation brush 6 starts to come into contact with the workpiece measurement surface Wf (the operation distance Da is longer). Become). Therefore, in this case, if the operating distance Dc of the rotating brush 6 until the complete conduction between the rotating brush 6 and the workpiece measurement surface Wf is obtained is about the same as that when the brush rotation speed is high, the brush 6 Similar to the case of low flexibility, generally, the slope of the voltage drop is relatively steep, as schematically shown in FIG. 5, for example.

  As described above, if the conditions such as the material and wire diameter of the hair material of the rotating brush 6 and the shape and basic size of the brush 6 are the same, the rotating brush 6 is greatly affected by the flexibility and the rotating speed. However, when the same rotating brush 6 is rotated at a plurality of different rotational speeds, the difference in the spreading method of the brush 6 due to the difference in rotational speed largely depends on the flexibility of the brush 6. By paying attention to this point, the flexibility of the rotating brush 6 can be determined relatively easily and easily.

  Next, the determination of the brush state using the finishing robot 1 will be described with reference to the flowchart of FIG. The determination of the brush state is performed, for example, according to the control program of the control unit 8 of the finishing robot 1. The control unit 8 includes a memory (storage device) storing a necessary program such as a control program, a flexibility evaluation value determined in advance for use in the brush state determination test, data obtained in the brush state determination test, and the like. Various storage devices such as a storage device for storage are built in or attached.

  When the brush state determination test starts, first, in step # 1, the rotating brush 6 is set to the initial position described above. Next, in step # 2, the rotational speed during the test of the rotary brush 6 is set. In the present embodiment, the measurement test is repeated by changing the rotation speed to a plurality of different values (for example, two kinds of values, high speed and low speed). Here, first, the first rotation at a relatively low speed is performed as the first measurement. Set to speed. Then, while rotating the rotating brush 6 at the first rotation speed, the movement is started preferably at a constant speed so as to bring the brush 6 closer to the workpiece measurement surface Wf (step # 3).

In this way, the detected value of the voltmeter 12 is continuously monitored while the rotary brush 6 is moved, and it is continuously determined whether or not the voltage V is below the first threshold (step # 4). The first threshold value is a threshold value for determining whether or not the rotating brush 6 has started to contact the workpiece measurement surface Wf. In the present embodiment, the first threshold value is, for example, 14 volts that is 1 volt lower than the maximum output of 15 volts so that the contact can be reliably detected.
If the determination result in step # 4 is YES (V <first threshold value), the brush position when the voltage V falls below the first threshold value while continuing the movement operation of the brush 6 (step # 5). Is recorded as the voltage change start position P1 of the rotary brush 6 when the voltage change occurs when the rotary brush 6 starts to contact the workpiece measurement surface Wf (step # 6). The data of the voltage change start position P1 is recorded in the memory of the control unit 8, for example.

While continuing the moving operation, the detected value of the voltmeter 12 is continuously monitored, and this time, it is continuously determined whether or not the voltage change ΔV within a certain period falls below the second threshold (step #). 7). In the process after the rotary brush 6 comes into contact with the workpiece measurement surface Wf, more preferably, the pressing load of the rotary brush 6 against the workpiece measurement surface Wf is controlled to be kept constant. The second threshold value is a threshold value for determining whether or not the voltage is substantially stabilized by the contact of the rotating brush 6 with the workpiece measurement surface Wf. In the present embodiment, the second threshold value is, for example, a voltage change of 0.1 volts per 2 mm operating distance so that it can be reliably detected that the voltage has stabilized.
When the determination result in step # 7 is YES (voltage change ΔV <second threshold value), the brush position when the voltage change ΔV falls below the second threshold value is indicated by the rotary brush 6 on the workpiece measurement surface Wf. For example, it is recorded in the memory of the control unit 8 as the voltage stabilization position Q1 of the rotating brush 6 when the voltage is sufficiently stabilized by the sufficient contact (step # 8).

  Thereafter, by returning the rotating brush to the initial position in step # 9, the first measurement at the low speed is completed. In step # 10, it is determined whether or not to change the rotation speed of the brush. In this case, since the first measurement has only been completed, the rotation speed needs to be changed, and the determination result in step # 10 is YES.

  And it returns to step # 2 and the setting which changes the rotational speed during the test of a rotating brush is performed. In this case, the second rotation speed is set to a relatively high speed (for example, twice the first rotation speed) as the second measurement, and each step from Step # 3 to Step # 9 is repeatedly executed. Is done. In this second measurement, in step # 6, the brush position when the voltage V falls below the first threshold is recorded as the voltage change start position P2 of the rotating brush 6 at the second rotational speed, and step # 6. 8, the brush position when the voltage change ΔV falls below the second threshold is recorded as the voltage stabilization position Q2 of the rotating brush 6 at the second rotational speed. The voltage change start position P2 and the voltage stabilization position Q2 of the rotary brush 6 at the second rotation speed are also recorded in the memory of the control unit 8, for example.

Then, when step # 10 is reached again, it is determined whether or not to change the rotation speed of the brush. In this case, since there are two types of rotation speeds to be set, high speed and low speed, there is no need to change the rotation speed any more. In step # 10, NO is determined, and the operation of the rotating brush 6 by the finishing robot is performed. All are stopped and the brush state determination test ends.
When the rotational speed is changed to more types, it is determined as YES in Step # 10, and Steps # 2 to # 9 are repeatedly executed.

  Thereafter, based on the recording data and the flexibility evaluation values of the voltage change start positions P1 and P2 and the voltage stabilization positions Q1 and Q2 obtained by the above measurement, for example, the brush state determination unit of the control unit 8 Thus, the flexibility of the rotating brush 6 is determined. For this determination, methods based on various determination criteria can be considered.

For example, the difference (Q1−P1) between the voltage change start position P1 and the voltage stabilization position Q1 at the first rotation speed, and the voltage change start position P2 and the voltage stabilization at a second rotation speed different from the first rotation speed. The flexibility of the rotating brush 6 can be determined based on the recording data of the difference (Q2-P2) from the conversion position Q2 and the predetermined flexibility evaluation value.
If the conditions such as the material and wire diameter of the bristle material and the shape and basic size of the rotating brush 6 are the same, and therefore the rotating brush 6 is the same, the centrifugal force acting on the brush 6 is generally the rotational speed. It can be said that the larger the brush is, the larger the brush is, and the higher the flexibility of the brush is, the more prominent the brush is spread by the action of centrifugal force.

Therefore, when the same rotating brush 6 is rotated at different rotational speeds, the second rotation is higher, depending on the degree of the rotational speed, the material of the bristle material, the brush type, shape, size, etc. The difference between the voltage change start position P2 at the speed and the voltage stabilization position Q2 (Q2-P2) and the difference between the voltage change start position P1 at the lower first rotation speed and the voltage stabilization position Q1 (Q1-P1) ), It is generally considered that a difference occurs according to the flexibility of the brush 6.
Therefore, the ratio (Q2-P2) / (Q1-P1) of the difference (Q2-P2) in the second rotation speed to the difference (Q1-P1) in the first rotation speed, or the difference between the two [(Q2-P2 )-(Q1-P1)] is obtained, and the flexibility of the rotating brush 6 can be determined based on the recording data of these values and a predetermined flexibility evaluation value.

  That is, by categorizing (classifying) these values, the flexibility of the rotating brush 6 can be determined, for example, as a new product or a new product, such as short-term use, medium-term use, and long-term use. Then, based on the determination result, for example, for a medium period use or a long period use, it is possible to optimize the use mode for each brush, such as using it in a place where the finishing width may be narrow to some extent. it can. Thereby, from the viewpoint of flexibility, one rotating brush 6 can be used up to the end of its life, and can greatly contribute to cost reduction of finishing work using the rotating brush 6.

However, when the same rotating brush 6 is rotated at different rotational speeds, the voltage at the higher second rotational speed depends on the material of the bristle material, the type of brush, shape and size, etc. The difference between the change start position P2 and the voltage stabilization position Q2 (Q2-P2) and the difference between the voltage change start position P1 and the voltage stabilization position Q1 at the lower first rotation speed (Q1-P1) There may be no noticeable difference and it may be difficult to classify the flexibility of the brush.
In such a case, it is one method to perform a determination test by changing the degree of difference in rotational speed (for example, by increasing the degree of difference in rotational speed). Alternatively, it may be possible to classify the flexibility of the brush by changing the determination method.

For example, the difference (P1−P2) between the voltage change start position P1 at the first rotation speed and the voltage change start position P2 at the second rotation speed different from the first rotation speed is obtained, and the recorded data of this value and The flexibility of the rotating brush 6 may be determined based on a predetermined flexibility evaluation value.
Furthermore, the recording data of the difference (Q1-Q2) between the voltage stabilization position Q1 at the first rotation speed and the voltage stabilization position Q2 at the second rotation speed different from the first rotation speed and the predetermined flexibility The flexibility of the rotating brush can also be determined based on the property evaluation value.

  When the rotational speed is changed over three or more types, the above determination method may be applied with the combination of any two of the rotational speeds as the first rotational speed and the second rotational speed.

  FIGS. 7 to 10 are graphs of changes in output voltage with respect to the operating distance of the brush, showing examples of brush state determination according to the present invention. FIG. 7 shows the case of a new brush made of carbon steel bristle material, and FIG. 8 shows the case after using the same carbon steel bristle brush to some extent. FIG. 9 shows the case of a new brush made of stainless steel hair material, and FIG. 10 shows the case after using the same brush made of stainless steel hair material to some extent. In any of these examples of FIGS. 7 to 10, an aluminum plate is used as the measurement workpiece W.

  Further, in all of the examples of FIGS. 7 to 10, the test was performed by changing the rotational speed of the brush 6 between three speeds of 2000 rpm, 3000 rpm, and 4000 rpm. In each graph, the case where the line data of A1 to A4 is a rotation speed of 2000 rpm, the case where the line data of B1 to B4 is a rotation speed of 3000 rpm, and the case where the line data of C1 to C4 is a rotation speed of 4000 rpm are shown. ing.

  Furthermore, in any of the examples of FIGS. 7 to 10, the pressing load on the workpiece measurement surface Wf of the rotating brush 6 is changed between four different loads at each rotation speed (test No. 1 to test 10). No. 4) was performed. In each graph of FIG. 7 to FIG. In the case of No. 1, the broken line data of A2, B2, and C2 indicate that the test No. In the case of No. 2, the line data of A3, B3, and C3 indicate that the test No. 3 and the broken line data of A4, B4, and C4 indicate that the test no. Cases 4 are shown respectively.

  Each of the polygonal line data A1 to A4, B1 to B4, and C1 to C4 shown in the graphs of FIGS. Table 1 shows the relationship.

図７から図１０のグラフにおいて、それぞれある程度のバラツキは認められるものの、概して言えば、回転速度が高いほどワーク計測面Ｗｆへの電圧変化開始位置に至る動作距離が短いことが分かる。
また、毛材が炭素鋼製の回転ブラシ６の場合、図７のグラフと図８のグラフとを比較すれば、同じ回転速度でも新品ブラシ（図７）の方がある程度使用したブラシ（図８）よりも、電圧変化開始位置に至る動作距離が短く、電圧安定化位置に至る動作距離が長いことが分かる。

Although the graphs of FIGS. 7 to 10 each show some variation, generally speaking, it can be seen that the higher the rotational speed, the shorter the operating distance to the voltage measurement start position on the workpiece measurement surface Wf.
Further, in the case where the bristle material is the rotating brush 6 made of carbon steel, comparing the graph of FIG. 7 with the graph of FIG. 8, the new brush (FIG. 7) used to some extent even at the same rotational speed (FIG. 8). ), The operating distance to the voltage change start position is short and the operating distance to the voltage stabilization position is long.

  In such a case, as can be seen in the graphs of FIGS. 7 and 8, for example, by comparing the polygonal lines A1, B1, and C1, there is a difference in the difference between the voltage change start position and the voltage stabilization position due to the difference in rotational speed. Often, the ratio is relatively large. Of the determination methods described above, the ratio (Q2−P2) / (Q1) of the difference (Q2−P2) in the second rotation speed to the difference (Q1−P1) in the first rotation speed. It is considered that the determination of the flexibility of the rotating brush 6 based on -P1) or the difference between them [(Q2-P2)-(Q1-P1)] can be effectively applied in many cases.

  On the other hand, in the case where the bristle material is the rotating brush 6 made of stainless steel, if the graph of FIG. 9 is compared with the graph of FIG. 10, the gap between the new brush (FIG. 9) and the brush used to some extent (FIG. 10). Thus, it can be seen that there is no significant difference in the required operating distance for each of the voltage change start position and the voltage stabilization position.

  In such a case, as can be seen in the graphs of FIGS. 9 and 10, for example, by comparing the polygonal lines A1, B1, and C1, there is a difference in the difference between the voltage change start position and the voltage stabilization position due to the difference in rotational speed. Often, the ratio is relatively small, and among the above-described determination methods, the ratio (Q2-P2) / (Q1) of the difference (Q2-P2) in the second rotation speed to the difference (Q1-P1) in the first rotation speed It is considered that the determination of the flexibility of the rotating brush 6 based on -P1) or the difference between the two [(Q2-P2)-(Q1-P1)] is not very effective in many cases.

  Therefore, in such a case, for example, the flexibility of the rotary brush 6 based on the difference (P1−P2) between the voltage change start position P1 at the first rotation speed and the voltage change start position P2 at the second rotation speed. Or other determinations such as determination of flexibility of the rotating brush 6 based on the difference (Q1-Q2) between the voltage stabilization position Q1 at the first rotation speed and the voltage stabilization position Q2 at the second rotation speed. Application of the method should be considered. Furthermore, it is one method to perform a judgment test by changing the degree of difference in rotational speed (for example, by making the degree of difference in rotational speed larger).

  As described above, according to the present embodiment, when the brush state of the rotating brush 6 having conductivity is determined, the rotating brush 6 measures each case when rotating at a plurality of different brush rotation speeds. The position of the rotating brush (voltage change start position) when a change occurs in the applied voltage between the workpiece W and the measured surface Wf of the measuring workpiece W, and the rotating brush 6 is more sufficiently measured by the measuring surface Wf of the measuring workpiece W. The position (voltage stabilization position) of the rotating brush 6 when the applied voltage is stabilized by contact is recorded, and the flexibility of the rotating brush 6 is based on the recorded data and a predetermined flexibility evaluation value. Is determined. That is, the difference in how the brush 6 spreads due to the difference in rotational speed can be quantitatively evaluated, and the flexibility of the rotating brush 6 can be determined based on quantitative data. That is, the flexibility of the rotating brush 6 can be determined quantitatively easily and easily as compared with the conventional technique that relies exclusively on the judgment of a skilled worker.

  In the above embodiment, the brush of the rotating brush 6 with respect to the change in the state of the applied voltage between the rotating brush 6 and the measurement surface Wf of the measurement workpiece W in each case when rotating at a plurality of different brush rotation speeds. The position is recorded, that is, when a change occurs in the applied voltage between the rotating brush 6 and the workpiece measurement surface Wf and the position of the rotating brush 6 when the applied voltage stabilizes (voltage change start position and voltage). (Stabilization position) is recorded, and the flexibility of the rotating brush 6 is quantitatively determined. Instead, the rotating brush 6 and the workpiece with respect to the change in the brush position of the rotating brush 6 are used. It is also possible to quantitatively determine the flexibility of the rotating brush 6 by recording the change in state of the applied voltage with the measurement surface Wf.

  In this case, in each case when rotating at a plurality of different brush rotation speeds, the applied voltage value (the first voltage between the rotary brush 6 and the workpiece measurement surface Wf when the rotary brush 6 moves to a predetermined first brush position) 1 voltage value) and an applied voltage value (second voltage value) between the rotary brush 6 and the workpiece measurement surface Wf when the rotary brush 6 moves to a second brush position separated from the first brush position by a predetermined amount. Thus, the flexibility of the rotating brush 6 is determined based on the recorded data and a predetermined flexibility evaluation value.

  In this method, at least one of the first brush position and the second brush position is a voltage change start position of the rotary brush 6 when a voltage change occurs when the rotary brush 6 starts to contact the workpiece measurement surface Wf. The rotary brush 6 should be in contact with the workpiece measurement surface Wf sufficiently to be present between the voltage stabilization position of the rotary brush 6 when the voltage is substantially stabilized and the first brush. Both the position of the second brush and the position of the second brush are such that when the rotary brush 6 starts to contact the workpiece measurement surface Wf and a voltage change occurs, the voltage change start position of the rotary brush 6 is sufficiently greater than the workpiece measurement surface Wf. It is preferable to select between the voltage stabilization position of the rotating brush 6 when the voltage is stabilized by contact. Thereby, since both the first brush position and the second brush position are selected between the position where the voltage change is started and the position where the voltage is substantially stabilized, the first voltage value at the first brush position It can be expected that the difference from the second voltage value at the second brush position becomes larger, and the accuracy of the brush flexibility determination can be improved.

As a more specific determination method, the difference (J1−K1) between the first voltage value (J1) and the second voltage value (K1) at the first rotation speed among a plurality of different brush rotation speeds, Recording data of a difference (J2−K2) between the first voltage value (J2) and the second voltage value (K2) at a second rotation speed different from the first rotation speed and a predetermined flexibility evaluation value Based on this, the flexibility of the rotating brush 6 can be determined.
In this case, the ratio (J2-K2) / (J1-K1) of the difference (J2-K2) in the second rotational speed to the difference (J1-K1) in the first rotational speed, or the difference between the two [(J2- K2) − (J1−K1)] is obtained, and the flexibility of the rotating brush 6 can be determined based on the recording data of these values and a predetermined flexibility evaluation value.

Alternatively, the difference (J1−J2) between the first voltage value J1 at the first rotation speed and the first voltage value J2 at the second rotation speed different from the first rotation speed is obtained, and the recorded data of this value The flexibility of the rotating brush 6 may be determined based on a predetermined flexibility evaluation value.
Furthermore, the recording data of the difference (K1−K2) between the second voltage value K1 at the first rotation speed and the second voltage value K2 at the second rotation speed different from the first rotation speed and the predetermined flexibility The flexibility of the rotating brush 6 can also be determined based on the sex evaluation value.

  Even in these cases, when determining the brush state of the rotating brush 6 having conductivity, the rotating brush 6 moves to a predetermined first brush position in each case when rotating at a plurality of different brush rotation speeds. The applied voltage value (first voltage value) between the workpiece measurement surface Wf and the workpiece measurement surface Wf when the rotary brush 6 moves to the second brush position separated by a predetermined amount from the first brush position. The applied voltage value (second voltage value) is recorded, and the flexibility of the rotating brush 6 is determined based on this recorded data and a predetermined flexibility evaluation value. That is, the difference in how the brush 6 spreads due to the difference in rotational speed can be quantitatively evaluated, and the flexibility of the rotating brush 6 can be determined based on quantitative data. That is, the flexibility of the rotating brush 6 can be determined quantitatively easily and easily as compared with the conventional technique that relies exclusively on the judgment of a skilled worker.

  In the above embodiment, the measurement surface Wf of the measurement workpiece W has a planar shape. However, the present invention is not limited to such a configuration, and the measurement surface Wf is, for example, a curved surface. Even a shape can be effectively applied. In the above embodiment, the rotary brush 6 is configured to move in the lateral direction (horizontal direction). However, the present invention is not limited to such a configuration, and the rotary brush 6 is, for example, the vertical direction. The present invention can also be effectively applied to the case of moving in other directions.

Furthermore, each of the above embodiments is an example of a conductive rotating brush used for finishing work. However, the present invention is not limited to such a case, and the conductive brush for other uses is used. The present invention can also be effectively applied to a rotating brush.
Thus, it goes without saying that the present invention is not limited to the above-described embodiments, and various changes or improvements can be made without departing from the scope of the invention.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used as an apparatus and method for determining a brush state of a rotating brush used for finishing a surface to be processed, particularly a rotating brush having conductivity.

DESCRIPTION OF SYMBOLS 1 Finishing robot 2 Base part 3 Robot arm 4 Robot hand 5 Motor 6 Rotating brush 6s Brush axis 8 Control unit 10 Electric circuit 11 Constant current power supply 12 Voltmeter J1 Voltage value in 1st brush position in 1st rotation speed J2 2nd Voltage value at the first brush position at the rotation speed K1 Voltage value at the second brush position at the first rotation speed K2 Voltage value at the second brush position at the second rotation speed P1 Voltage change start position at the first rotation speed P2 Voltage change start position at the second rotation speed Q1 Voltage stabilization position at the first rotation speed Q2 Voltage stabilization position at the second rotation speed W Measurement work Wf Work measurement surface

Claims (10)

A brush state determination device for determining a brush state of a conductive rotary brush,
A brush moving means for moving the rotating brush so as to be able to contact and separate from the surface of the workpiece for measurement while rotating the rotating brush;
Rotation speed switching means for switching the rotation speed of the rotating brush between a plurality of different brush rotation speeds;
A power supply device for applying a voltage between the rotating brush and the measurement work surface;
Voltage detecting means for detecting a voltage change between the rotating brush and the measurement work surface when contacting the surface;
Based on the output value of the voltage detection means, the voltage change start position of the rotating brush when the rotating brush starts to contact the measuring work surface and a voltage change occurs, and the rotating brush is more fully connected to the measuring work surface. Recording means for recording the voltage stabilization position of the rotating brush when the voltage is substantially stabilized by contact, for each of the plurality of different brush rotation speeds;
Determination means for determining the flexibility of the rotating brush based on the recording data of the recording means and a predetermined flexibility evaluation value;
A brush state determination device for a conductive rotary brush, comprising:   The determination means includes a difference between a voltage change start position and a voltage stabilization position at a first rotation speed among the plurality of different brush rotation speeds, and a voltage at a second rotation speed different from the first rotation speed. The brush state according to claim 1, wherein the flexibility of the rotating brush is determined based on recording data of a difference between the change start position and the voltage stabilization position and a predetermined flexibility evaluation value. Judgment device.   The determination unit records a difference between a voltage change start position at a first rotation speed among the plurality of different brush rotation speeds and a voltage change start position at a second rotation speed different from the first rotation speed. The brush state determination device according to claim 1, wherein the flexibility of the rotating brush is determined based on data and a predetermined flexibility evaluation value.   The determination unit records a difference between a voltage stabilization position at a first rotation speed among the plurality of different brush rotation speeds and a voltage stabilization position at a second rotation speed different from the first rotation speed. The brush state determination device according to claim 1, wherein the flexibility of the rotating brush is determined based on data and a predetermined flexibility evaluation value. A brush state determination device for determining a brush state of a conductive rotary brush,
A brush moving means for moving the rotating brush so as to be able to contact and separate from the surface of the workpiece for measurement while rotating the rotating brush;
Rotation speed switching means for switching the rotation speed of the rotating brush between a plurality of different brush rotation speeds;
A power supply device for applying a voltage between the rotating brush and the measurement work surface;
Voltage detecting means for detecting a voltage change between the rotating brush and the measurement work surface when contacting the surface;
A first voltage value detected by the voltage detecting means when the rotating brush has moved to a predetermined first brush position by the brush moving means, and a second value in which the rotating brush is separated from the first brush position by a predetermined amount. Recording means for recording a second voltage value detected by the voltage detection means when moving to a brush position for each of the plurality of different brush rotation speeds;
Determination means for determining the flexibility of the rotating brush based on the recording data of the recording means and a predetermined flexibility evaluation value;
A brush state determination device for a conductive rotary brush, comprising: A brush state determination method for determining a brush state of a conductive rotating brush,
A brush moving step of moving the rotating brush so as to be able to contact and separate from the surface of the workpiece for measurement while rotating the rotating brush;
A rotational speed switching step of switching the rotational speed of the rotating brush between a plurality of different brush rotational speeds;
In the brush moving step, when the rotating brush comes into contact with the measurement workpiece surface, a voltage detecting step for detecting a change in voltage applied between the two,
Based on the output value obtained in the voltage detection step, the voltage change start position of the rotating brush when the rotating brush starts to contact the measuring work surface and a voltage change occurs, and the rotating brush is the measuring work surface. Recording step for recording the voltage stabilization position of the rotating brush when the voltage is substantially stabilized by sufficiently contacting with each of the plurality of different brush rotation speeds;
A determination step of determining the flexibility of the rotating brush based on the recording data obtained in the recording step and a predetermined flexibility evaluation value;
A method for determining a brush state of a conductive rotating brush.   In the determination step, the difference between the voltage change start position and the voltage stabilization position at the first rotation speed among the plurality of different brush rotation speeds, and the voltage at the second rotation speed different from the first rotation speed. The brush state according to claim 6, wherein the flexibility of the rotating brush is determined based on recording data of a difference between the change start position and the voltage stabilization position and a predetermined flexibility evaluation value. Judgment method.   In the determination step, a difference between a voltage change start position at a first rotation speed among the plurality of different brush rotation speeds and a voltage change start position at a second rotation speed different from the first rotation speed is recorded. The brush state determination method according to claim 6, wherein the flexibility of the rotating brush is determined based on data and a predetermined flexibility evaluation value.   In the determination step, a difference between a voltage stabilization position at a first rotation speed among the plurality of different brush rotation speeds and a voltage stabilization position at a second rotation speed different from the first rotation speed is recorded. The brush state determination method according to claim 6, wherein the flexibility of the rotating brush is determined based on data and a predetermined flexibility evaluation value. A brush state determination method for determining a brush state of a conductive rotating brush,
A brush moving step of moving the rotating brush so as to be able to contact and separate from the surface of the workpiece for measurement while rotating the rotating brush;
A rotational speed switching step of switching the rotational speed of the rotating brush between a plurality of different brush rotational speeds;
In the brush moving step, when the rotating brush comes into contact with the measurement workpiece surface, a voltage detecting step for detecting a change in voltage applied between the two,
The first voltage value detected when the rotating brush has moved to a predetermined first brush position in the brush moving step, and the rotating brush moved to a second brush position separated by a predetermined amount from the first brush position. A recording step of recording the second voltage value detected at the time of each of the plurality of different brush rotation speeds;
A determination step of determining the flexibility of the rotating brush based on the recording data obtained in the recording step and a predetermined flexibility evaluation value;
A method for determining a brush state of a conductive rotating brush.

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