Patent Description:
A typical technique of performing exterior coating has been provided, involving using a coating device including a coating head having a plurality of nozzles for ejecting paint. For example, in a production plant of an automobile, a technique has been proposed in which a coating device composed of a multi-joint robot having the above-mentioned coating head disposed at the front end is installed in a coating line to coat a vehicle body. In the coating process by the coating head, since a coating material having a viscosity different from that of the ink used for printing on a paper surface is used, clogging of the nozzles due to adhesion of coating residues probably occur in the nozzles.

Therefore, there is provided a technique that includes detecting the state of the coating agent or the paint droplets ejected from the coating device and cleaning each nozzle of the coating head before clearing the clogging (see Patent Document <NUM>). In Patent Document <NUM>, a light source for emitting inspection light and a camera disposed in a cleaning device for capturing droplets irradiated by the light source, where the image captured by the camera is used to evaluate the number of droplets, the ejection angle of droplets, and whether the ejection direction of the droplets ejected from each nozzle is closed, to detect whether there is clogging. Patent document <NUM> refers to a method for inspecting jetting state of inkjet head and apparatus for inspecting jetting state of inkjet head. Patent document <NUM> describes a method and an apparatus for inspecting clogging of ink ejection nozzle. Patent document <NUM> describes an application apparatus, in which the formation of a test pattern by applying color materials from all nozzles is performed after a first scan of an application gantry. In parallel with the double-action scans of the application gantry, a camera gantry starts a scan to take the test patterns applied just before, with a scan camera. Patent document <NUM> provides a system and methods for manufacturing an optical member, such as a color filter, using a scanning ink-jet head, where all nozzles of the ink-jet head precisely scan formation regions of pixels.

Patent Document <NUM>: <CIT>; patent document <NUM>: <CIT>; patent document <NUM>: <CIT>; patent document <NUM>: <CIT>; patent document <NUM>: <CIT>.

The cleaning device disclosed in Patent Document <NUM> has an advantage that detection of the presence or absence of clogging and nozzle cleaning can be performed using a single device. However, according to Patent Document <NUM>, detecting clogging, a degree of clogging and the like, is performed for the purpose of nozzle cleaning when the paint color is changed or during the period of stopping coating, rather than detecting clogging and a degree of clogging occurring during the coating process. Therefore, in Patent Document <NUM>, it is impossible to detect the presence or absence of clogging that has occurred in multiple successive coatings, i.e., it cannot be detected whether coating defect has occurred.

The present disclosure is proposed for solving the above problem, with the objective to provide a technique that can prevent coating defect caused by clogging in multiple successive coatings.

In order to solve the above problem, an example of the coating determining device of the coating head according to the present disclosure, where the coating head having a plurality of nozzles for ejecting paint, the plurality of nozzles being configured to eject the paint out of the nozzles so as to coat a workpiece with the ejected paint while moving in a direction, the coating determining device of the coating head comprising: an image acquiring unit for acquiring an image of the coated workpiece; and a determination unit for determining, based on the image acquired by the image acquiring unit, whether coating the workpiece is implemented normally.

The coating determining device further comprises: an extraction unit for extracting coating defect in the workpiece from the image of the coated workpiece, wherein when the extraction unit determines that the coating defect in the workpiece, the determination unit determines the nozzles in which the ejecting defect occurs from the plurality of nozzles comprised by the coating head.

In addition, the coating head comprises a control unit for controlling ejection of the paint of the plurality of nozzles for the nozzle, the control unit cooperates with the coating head to move in a direction, and applies to the workpiece with a pattern for determination for determining whether there is a ejecting defect for the paint, using the plurality of nozzles comprised by the coating head, and the determining unit determines, based on an image of the workpiece coated with the pattern for determination, whether coating the workpiece is implemented normally.

In the case, the coating head is provided with a plurality of nozzle rows in a direction orthogonal to the direction, the nozzle rows each including a predetermined number of nozzles arranged in a direction inclined relative to the direction, the pattern for determination at least comprises a plurality of baselines configured in a <NUM>-dimensional shape and extending along the direction, and when the coating head is moving in a direction, the control unit, while switching the nozzles, coats the plurality of baselines onto the workpiece by continuously ejecting the paint baselines from any one of the predetermined number of nozzles comprised by each of the plurality of nozzle rows.

In the image of the pattern for determination acquired by the image acquiring unit, for the baselines formed using any one from the predetermined number of nozzles comprised by a same nozzle row, when the coating defect occurs in more than a predetermined number of baselines, the determination unit determines that coating the workpiece is not implemented normally using the coating head.

The coating determining device further comprises: at least one camera unit for capturing an image of the workpiece at a plurality of different positions; a <NUM>-dimensional image generating unit for generating, using the image acquired by the at least one camera unit, a <NUM>-dimensional image of the workpiece coated by the coating head; and a state determining unit for determining, using the <NUM>-dimensional image of the workpiece generated by the <NUM>-dimensional image generating unit, a coated state of the workpiece.

The coating determining device further comprises: an instruction unit for instructing to apply the pattern for determination for determining presence or absence of a in ejecting defect for the paint when the state determining unit determines that the thickness of the paint is below the predetermined thickness, wherein the state determining unit determines, using the <NUM>-dimensional image, whether a thickness of the paint coated over the workpiece is below a predetermined thickness.

A coating system according to the present disclosure comprises: a coating head comprising a plurality of nozzles; a moving unit disposed within a coating chamber subjected to an explosion-proof treatment and configured to move the coating head along a workpiece in a direction; the coating determining device of the coating head; and a cleaning unit for cleaning the plurality of nozzles comprised by the coating head, wherein when the coating determining device of the coating head determines that coating the workpiece is not implemented normally, the cleaning unit cleans the plurality of nozzles comprised by the coating head.

The workpiece comprises a first workpiece for determining whether coating the workpiece is implemented normally in the coating determining device of the coating head, the coating determining device of the coating head is disposed outside the coating chamber, and the coating system further comprises a transport unit for transporting the first workpiece coated by the coating head to the coating determining device of the coating head.

According to the present disclosure, coating defect caused by clogging in multiple successive coatings can be avoided.

References now are made to the drawings to illustrate a coating system for carrying out the present disclosure. As illustrated in <FIG>, the coating system <NUM> includes a coating robot <NUM>, an image processing device <NUM>, a transport device <NUM> and a coating determining device <NUM>. It is to be noted that the coating robot <NUM> in the coating system <NUM> is disposed within a coating chamber <NUM> subj ected to an explosion-proof treatment, and the image processing device <NUM> is disposed outside the coating chamber <NUM>. In addition, the coating determining device <NUM> is disposed within an inspection chamber <NUM> adjacent to the coating chamber <NUM>. The transport device <NUM> is disposed across the coating chamber <NUM> and the inspection chamber <NUM>.

Although omitted in the drawings, the object to be coated is transported from the upstream of the coating line to the inside of the coating chamber <NUM>. The object to be coated is subjected to coating while being transported into the coating chamber <NUM> or temporarily stopped when transported to a predetermined position in the coating chamber <NUM>. When the object to be coated has been subjected to coating, it is indicated that the object to be coated is transported from the coating chamber <NUM> to the downstream of the coating line. Hereinafter, the vehicle body FR of the automobile will be described as an example of the object to be coated, but the object to be coated may be, for example, an automobile part other than the vehicle body (as one example, a door, a hood, various panels, and the like, but the present invention is not limited thereto), and other parts (as an example, an airplane or a railway exterior part) other than the automobile, and the like, there is no need to be limited to the vehicle body of the automobile.

Moreover, in the following description, a coating system <NUM> for coating a vehicle body FR by using one coating robot <NUM> will be described, but coating system <NUM> may be a coating system for coating a vehicle body FR using two or more coating machines <NUM>.

The objective of coating is to form a coating film on a surface of an object to be coated to protect the surface thereof and attain a pleasant appearance. To this end, in addition to coating an object to be coated using paint of a specific color or a paint having a specific function, coating includes coating an object to be coated by using paint of multiple colors in order. Furthermore, the coating includes, for example, coating such as a pattern, an illustration, an image or the like.

For example, the coating robot <NUM> includes a substrate <NUM>, a leg <NUM>, a rotatable drive unit <NUM>, a mechanical arm <NUM> and a coating head unit <NUM>. The substrate <NUM> is a member that holds an underside of the leg <NUM> extending in the vertical direction and supports the entire coating robot <NUM>. The substrate <NUM> can be fixed on, for example, the floor surface of the coating chamber <NUM>, or may be movable within the coating chamber <NUM>. It would be appreciated that the coating robot <NUM> is rotatable between a position (denoted by a solid line in <FIG>) of the coating robot <NUM> for coating the vehicle body FR transported in the coating line and a position (denoted by a double-dotted line in <FIG>) of the coating robot <NUM> for coating a sample S with a test pattern TP (referring to <FIG>), with the leg <NUM> being the rotation center. The vehicle body FR and the sample S here is equivalent to the workpiece as recited in the technical solution.

A rotatable drive unit <NUM> is disposed at an upper end of the leg <NUM>. The rotatable drive unit <NUM> includes a rotatable shaft unit <NUM> and a rotatable arm <NUM>. The rotatable shaft unit <NUM> causes the mechanical arm <NUM> linked via the rotatable arm <NUM> to rotate around a straight line included in a plane (an XY plane in <FIG>) parallel to the ground as a rotation center. The rotatable arm <NUM> is disposed between the rotatable shaft unit <NUM> and the mechanical arm <NUM>. When driven by a motor M1 (see <FIG>), the rotatable arm <NUM> rotates with the central axis of the rotary shaft of the motor M1 (i.e., the central axis of the rotatable shaft unit <NUM>) as a rotation center. Examples of the motor M1 can include an electric motor or a pneumatic motor.

The mechanism arm <NUM> includes a first rotatable arm <NUM> and a second rotatable arm <NUM>. The first rotatable arm <NUM> is linked to the rotatable arm <NUM> via a shaft section not shown in the figure at an end in the extending direction of the first rotatable arm <NUM> (e.g. the X-axis direction in <FIG>), and driven via a motor M2 (see <FIG>) to rotate around the center axis of the shaft section, which acts as a rotation center. It is worth noting that, although not shown in detail in the figure, the motor M2 is housed within the housing of the rotatable arm <NUM> or the housing of the first rotatable arm <NUM>.

The second rotatable arm <NUM> is linked to the first rotatable arm <NUM> via the shaft section not shown in the figure at the other end in the extending direction of the first rotatable arm <NUM> (e.g. the X-axis direction in <FIG>), and driven via a motor M3 (see <FIG>) to rotate around the central axis of the shaft unit, which acts as a rotation center. It is worth noting that, although not shown in the figure, the motor M3 is housed within the housing of the first rotatable arm <NUM> or the housing of the second rotatable arm <NUM>.

The second rotatable arm <NUM> holds a wrist <NUM> at the other end opposite the end linked to the first rotatable arm <NUM>. In a state of retaining the coating head unit <NUM>, the wrist <NUM> causes the retained coating head unit <NUM> to rotate around a certain shaft section among a plurality of shaft sections included therein, which acts as a rotation center. For example, the pluralities of shaft sections are <NUM> shaft sections in different directions. It is worth noting that the number of shaft section can be two or more.

The wrist <NUM> includes motors M4, M5 and M6 (see <FIG>). When driven by a any one of those motors, the wrist <NUM> enables rotational motion around the shaft section corresponding to the motor to be driven among the plurality of shaft sections, which acts as the rotation center.

The coating head <NUM> includes a head control unit <NUM> and the like. The head control unit <NUM> controls a coating head <NUM>, a circular path for circulating paint (not shown in the figure), and a piezoelectric substrate <NUM> (see <FIG>) included in the coating head <NUM>.

<FIG> is a front view of a nozzle forming surface of the coating head <NUM>. As shown therein, the nozzle forming surface <NUM> includes two nozzle groups 32a, 32b configured along a primary scanning direction in the coating head unit <NUM> (i.e., the S1 direction in <FIG>). As shown in <FIG>, the nozzle group 32a is configured with a plurality of nozzle rows 34a configured in a secondary scanning direction (i.e., the S2 direction in <FIG>) orthogonal to the primary scanning direction, where the nozzle row <NUM> is formed by, for example, four nozzles <NUM> spaced apart in a certain interval along a straight line L1 inclined at a predetermined angle relative to the primary scanning direction. Here, if the four nozzles forming the nozzle row <NUM> include a nozzle 33a, a nozzle 33b, a nozzle 33c and a nozzle 33d from the upper part in <FIG>, the nozzles 33a of the each nozzle rows 34a are at the same locations. Likewise, nozzles 33b, nozzles 33c, and nozzles 33d in the each nozzle rows 34a are at the same locations in the primary scanning direction. Here, when the interval between two adjacent nozzles <NUM> in the same nozzle row 34a in the secondary scanning direction is set to D1, the interval D2 between two nozzles 33a, 33d adjacent to each other in the secondary scanning direction located at respective ends of two adjacent nozzle rows 34a is the same as the interval D1 (D1 = D2).

Similarly, the nozzle group 32b includes a plurality of nozzle rows 32b in the secondary scanning direction, where the nozzle row 34b is formed by four nozzles <NUM> arranged in a straight line L2 inclined at a predetermined angle relative to the primary scanning direction. Here, the straight line L1 is parallel to the straight line L2. When the four nozzles in the nozzle row 34b are set as a nozzle 33e, a nozzle 33f, a nozzle <NUM>, and a nozzle <NUM> from the upper part in <FIG>, the nozzles 33e in the each nozzle rows 34b are at the same locations in the primary scanning direction. Likewise, nozzles 33f, nozzles <NUM> and nozzles <NUM> in the each nozzle rows 34b are at the same locations in the primary scanning direction. It is worth noting that, although not shown in the figure, an interval D3 between two adjacent nozzles <NUM> in the same nozzle row 34b in the secondary scanning direction, and an interval D4 between two nozzles 33e, <NUM> adjacent to each other in the second scanning direction located at respective ends of two adjacent nozzle rows 34b are identical to the interval D1 (D3 = D4 = D1).

In addition, among the nozzle groups 32a, 32b, each nozzle rows 34b in the nozzle group 32b is disposed in the secondary scanning direction at locations offset a distance D1/<NUM> from the respective arrays 34a in the nozzle group 34a.

Therefore, as shown in <FIG>, if each nozzles <NUM> disposed on the nozzle forming surface <NUM> are projected onto the same projection plane PL1, the nozzle 33a in the nozzle row 34a is disposed between the nozzle 33e and the nozzle 33f in the nozzle row 34b. In addition, the nozzle 33b of the nozzle row 34a is disposed between the nozzle 33f and the nozzle <NUM> in the nozzle row 34b. Besides, the nozzle 33c of the nozzle row 34a is disposed between the nozzle <NUM> and the nozzle <NUM> of the nozzle row 34b. As such, two nozzle groups 32a, 32b formed on the nozzle forming surface <NUM> are used during coating to increase the point density.

Returning to <FIG>, the image processing device <NUM> generates, based on CAD data corresponding to a coating range of a vehicle, a <NUM>-dimensional model (a <NUM>-dimesnional model for coating) of measurement data obtained by measuring a real vehicle. In addition, the image processing device <NUM> generates, based on trajectory data stored in an arm memory <NUM> (see <FIG>) and the generated <NUM>-dimensional model for coating, <NUM>-dimensional image data (coating pattern data) used when the coating head unit <NUM> is performing coating. The coating pattern data is data obtained by dividing a coating region in a vehicle body FR, and sends the same sequentially to the coating robot <NUM> when the vehicle body FR is being coated.

The transport device <NUM> conveys the sample S coated with a test pattern by the coating robot <NUM> from the coating chamber <NUM> to the inspection chamber <NUM>. the transport device <NUM> is, for example, a conveyor device.

The coating determining device <NUM> captures the test pattern TP coated over the sample S, and determines, based on the captured camera data and image data for determination, whether coating by the coating head unit <NUM> is normally performed, i.e., whether coating defect occurs.

The coating determining device includes a camera section <NUM>, a light source <NUM> and a computer <NUM>. The camera section <NUM> captures a coated surface of the sample S transported by the transport device <NUM>. The light source <NUM> illuminates the coated surface of the sample S transported by the transport device <NUM>. The computer <NUM> controls driving of the camera section <NUM> and the light source <NUM>. In addition, the computer <NUM> determines whether coating defect occurs based on the camera data acquired by the camera section <NUM> and image data used for determination. Alternatively, the computer <NUM> determines whether coating defect occurs based on the camera data acquired by the camera section <NUM> and baseline information (e.g. for value threshold of a linear pixel for determining, a width of a linear portion, and the like) other than the image data for determining coating defect. In the case of determining that coating defect occurs, the coating robot <NUM> is instructed to clean the coating head unit <NUM>.

Next, the test pattern TP is coated on the coated surface of the sample S. As shown in <FIG>, the test pattern TP has a plurality of baselines MCL extending along the primary scanning direction (the S1 direction in <FIG>) and a plurality of baselines SCL extending along the secondary scanning direction (the S2 direction in <FIG>).

The baselines SCL extending along the secondary scanning line are generated by droplets of the paint ejected from the plurality of nozzles <NUM> of the coating head unit <NUM> disposed on the nozzle forming surface when the nozzles <NUM> reaching the specific locations in the primary scanning direction.

As shown in <FIG>, the baselines MCL extending along the primary scanning direction are generated in such a fashion that: when the nozzles <NUM> ejecting the paint droplets are being switched, all the nozzles <NUM> belonging to the same group perform the following act: in the case that the nozzle row 34a from the nozzle group 32a and the nozzle row 34b from the nozzle group 32b in the same line counted from the left side in <FIG> in the secondary scanning direction (the S2 direction in <FIG>) on the nozzle forming surface <NUM> are divided into the same group (Gr1, Gr2, Gr3. ), when the coating head <NUM> is moving along the primary scanning direction, a certain nozzle from the nozzles in the same group continuously eject paint droplets multiple times (see below for which nozzle forms which baseline MCL). The number of baselines MCL and the baselines SCL are varied with the number of nozzles disposed on the nozzle forming surface <NUM>.

As described above, the nozzle row 34a from the nozzle group 32a and the nozzle row 34b from the nozzle group 32b provide with four nozzles <NUM>, respectively. Therefore, the test pattern TP as shown in <FIG> includes eight baselines MCL1 - MCL8 extending along the primary scanning direction and <NUM> baselines SCL1 - SCL9 extending along the secondary scanning direction, where the <NUM> baselines MCL1 - MCL <NUM> correspond to the number of groups divided in the secondary scanning direction.

In <FIG>, the baseline MCL1 is a baseline formed by the paint continuously ejected from the nozzle 33e in the nozzle row 34b of the nozzle group 32b multiple times. The baseline MCL2 is a baseline formed by the paint ejected continuously from the nozzle 33a in the nozzle row 34a of the nozzle group 32a. The baseline MCL3 is a baseline formed by the paint continuously ejected from the nozzle 33f in the nozzle row 34b of the nozzle group 32b. The baselines MCL4 is a baseline formed by the paint continuously ejected from the nozzle 33b in the nozzle row 33a of the nozzle group 32a.

In addition, the baseline MCL5 is a baseline formed by the paint continuously ejected from the nozzle <NUM> in the nozzle row 34b of the nozzle group 32b. The baseline MCL6 is a baseline formed by the paint continuously ejected from the nozzle 33c in the nozzle row 34a of the nozzle group 32a. The baselines MCL7 is a baseline formed by the paint continuously ejected from the nozzle <NUM> in the nozzle row 34b of the nozzle group 32b. The baseline MCL8 is a baseline formed by the paint continuously ejected from the nozzle 33d in the nozzle row 34a of the nozzle group 32a.

It is to be noted that the test pattern TP determines the presence or absence of clogging of the plurality of nozzles <NUM> disposed on the nozzle forming surface <NUM>. Accordingly, the baselines SCL extending along the secondary scanning direction are not necessary, and the test pattern TP may be a test pattern only having baselines MCL extending along the primary scanning direction.

Control composition in the coating system <NUM> according to the present implementation will be described below. <FIG> is a diagram illustrating control composition in the coating system <NUM>. As shown therein, the coating system <NUM> includes a management device <NUM> and a nozzle cleaning device <NUM>, in addition to the coating robot <NUM>, the image processing device <NUM>, the transport device <NUM> and the coating determining device <NUM>.

The coating robot <NUM> includes a primary control section <NUM>, an arm control section <NUM>, a paint supply control section <NUM> and a head control section <NUM>. Although not shown, the primary control section <NUM>, the arm control section <NUM>, the paint supply control section <NUM> and the head control section <NUM> are comprised of a CPU (Central Processing unit), a storage portion (ROM (Read Only Memory)), a RAM (Random Access Memory), a nonvolatile memory or the like, and other elements.

The primary control section <NUM> sends a predetermined control signal to the arm control section <NUM>, the paint supply control section <NUM> and the head control section <NUM>, respectively, to cause the motors M1, M2, M3, M4, M5 and M6, the paint supply section <NUM> and the piezoelectric substrate <NUM> to act in cooperation to perform coating on the object to be coated.

The arm control section <NUM> controls driving of the motors M1, M2, M3, M4, M5 and M6. The arm control section <NUM> includes an arm memory <NUM>. The arm memory <NUM> stores data (trajectory data) related to trajectories of the coating head unit <NUM> created from a robot view and taking into consideration a width (referred to as coating width below) coated on the object to be coated in the primary scanning direction when the coating head unit <NUM> is caused to move along the primary scanning direction, and data (posture data) related to postures of the coating head unit <NUM>, such as an inclined angle of the coating head unit <NUM> and the like.

In addition, the arm control section <NUM> controls driving of the motors M1, M2, M3, M4, M5 and M6 based on the trajectory data and posture data stored in the memory <NUM> and the image processing performed by the image processing device <NUM>. As an effect of control of the motors M1, M2, M3, M4, M5 and M6, the coating head unit <NUM> can pass the target position at a determined speed or stop at the target position when performing coating. It would be appreciated that the arm memory <NUM> can be disposed on the coating robot <NUM>, or can be disposed outside the coating robot <NUM>. When disposed outside the coating robot <NUM>, the arm memory <NUM> is preferably connected to a communication unit, where the communication unit can communicate with an external machine in a wireless or cabled fashion.

The paint supply control section <NUM> controls the supply of paint to the coating head <NUM>. Although not shown in the drawings, the paint supply control section <NUM> controls actions of a pump, a valve and the like included in the paint supply section <NUM>, so as to cause the paint stored in the paint tank, box and the like connected to the paint supply section <NUM> to circulate between the paint supply section <NUM> and the coating head unit <NUM>.

The head control section <NUM> controls the action of the piezoelectric substrate <NUM> of the coating head <NUM> based on the data generated during image processing performed in the image processing device <NUM>, and position information from a position sensor <NUM> described below. In other words, when determining, based on the position information from the position sensor <NUM>, that the coating head <NUM> arrives at the predetermined position in the trajectory data, the head control section <NUM> causes the piezoelectric substrate <NUM> to act, based on coating data corresponding to the position. Here, the head control section <NUM> cannot only control the action of the piezoelectric substrate <NUM>, but can also control an amount of droplets respectively ejected from the plurality of nozzles <NUM> disposed on the nozzle forming surface <NUM>.

The position sensor <NUM> detects the position of the coating head <NUM> that moves under the control of the arm control unit <NUM>, and outputs a detection signal to the primary control section <NUM>.

The transport device <NUM> includes a drive control unit <NUM>, a motor M7 and a drive roller <NUM>. The drive control unit <NUM> drives the motor M7 based on a drive signal sent from the coating robot <NUM>, to rotate the drive roller <NUM>. The drive roller <NUM> is driven by the motor M7 to rotate, thus causing a coiled conveyor belt <NUM> across the drive roller <NUM> and a driven roller <NUM> (see <FIG>) to move such that a sample S carried on the conveyor belt <NUM> is transported from the coating chamber <NUM> to the inspection chamber <NUM> (the arrow direction in <FIG>).

Moreover, as described with reference to <FIG>, the coating determining device <NUM> includes a camera section <NUM>, a light source <NUM> and a computer <NUM>. The computer <NUM> includes a control unit <NUM>, an operation unit <NUM> and a display panel <NUM>. The control unit <NUM> includes a primary control section <NUM>, a camera control section <NUM>, a light-emitting control unit <NUM> and a display control unit <NUM>. By executing a determining program <NUM> stored in the memory <NUM> included in the control unit <NUM>, the primary control section <NUM> can implement respective functions of an image processing section <NUM>, an extraction section <NUM> and a determining unit <NUM>.

The image processing section <NUM> performs image processing, such as scaling processing and the like, in addition to processing including denoising, destraining, brightness adjustment, and the like, performed on image data (hereinafter referred to as camera data) of the test pattern TP captured by the camera section <NUM>, and contour extraction processing. In addition, as required, the image processing section <NUM> can perform binarization processing on the camera data. It is worth noting that the scaling processing refers to scaling up/down a size of a test pattern TP in an image based on camera data, to match the size of the test pattern TP in the image based on determination image data <NUM>.

Using the determination image data <NUM> stored in the memory <NUM> and camera data (hereinafter referred to as processed data) obtained by image processing performed by the image processing section <NUM>, the extraction section <NUM> extracts uncoated baselines MCL (missed from the coating) included in the test pattern TP. In the processed data, the coated baselines MCL are presented in the form of contour while the uncoated baselines MCL are not presented in this form. Therefore, when comparing the plurality of baselines MCL included in the determination image data <NUM> with a plurality of contours included in the processed data, the extraction section <NUM> extracts uncoated baselines MCL.

It is to be noted that the extraction section <NUM> can obtain the difference data between the processed data and the determination image data <NUM>, and if the difference data within the range of coating the test pattern TP include a predetermined amount of pixels with pixel values exceeding a predetermined range in the primary scanning direction, the baselines MCL of the respective part are extracted as uncoated baselines MCL.

When none of a plurality of nozzles <NUM> disposed on the nozzle forming surface <NUM>, for example, is clogged (i.e., in a normal state), all of the baselines MSL in the test pattern TP coated on the sample S are coated. The determination image data <NUM> are data acquired by coating all the baselines in the test pattern TP. As such, since the processed data include contours of respective baselines MCL for forming the test pattern TP, the uncoated baselines MCL are not extracted.

On the other hand, if the one of the plurality of nozzles <NUM> disposed on the nozzle forming surface <NUM>, for example, is clogged, the baselines MCL corresponding to the nozzle <NUM> are not coated.

Therefore, the processed data do not include contours of the baselines MCL corresponding to the nozzle <NUM> among the baselines MCL forming the test pattern TP. In the case, the uncoated baselines MCL are extracted.

The extraction section <NUM> extracts the uncoated baselines MCL using the determination image data <NUM> and the processed data, and generates extraction data indicative of an extraction result. For example, when the uncoated baselines MCL are extracted, the extraction data include position information of the uncoated baselines MCL.

The determining section <NUM> determines whether coating defect occurs by using the extraction data generated by the extraction section <NUM>. Coating defect will be described below. The determining unit <NUM> sends to the management device <NUM> a determination result as to whether coating defect occurs.

The management device <NUM> includes a CPU, a memory, and the like, which are not shown in the figure, and performs comprehensive control on the coating robot <NUM>, the image processing device <NUM>, the transport device <NUM> and the coating determining device <NUM> which jointly form the coating system <NUM>. The management device <NUM> sends, based on the determination result as to whether coating defect occurs, a signal indicative of performing cleaning to the coating robot <NUM> and a nozzle cleaning device <NUM>.

The nozzle cleaning device <NUM> is a device for cleaning the nozzle forming surface <NUM> of the coating head <NUM>.

Coating defect is now described. For example, the coating defect refer to that more than <NUM> baselines MCL are not coated among baselines MCL1 - MCL8 generated by the paint ejected from the nozzles divided into the same group Gr1, Gr2. as shown in <FIG>. Coating defect will be illustrated below.

As shown in <FIG>, for example, when each nozzles <NUM> in the same group normally eject the paint, all the baselines MCL1 - MCL <NUM> are coated. On the other hand, if the one in a plurality of nozzles <NUM> in the same group is clogged, a baseline MCL corresponding to the clogged nozzle <NUM> is not coated. In <FIG>, for example, MCL3, MCL4 and MCL5 are not clogged which are denoted by dotted lines. As shown in <FIG>, the nozzle 33b, nozzle 33f and nozzle <NUM> are adjacent nozzles <NUM> when projected onto the same projection plane PL1. If a vehicle body FR is coated in the state, the coated vehicle body FR includes a strip region not coated with the paint.

As shown in <FIG>, when the baseline MCL2, the baseline MCL4 and the baseline MCL6 are not coated, the nozzle 33a corresponding to the baselines MCL2, the nozzle 33b corresponding to the baseline MCL4 and the nozzle 33c corresponding to the MCL6 are clogged. In <FIG>, the uncoated baselines MCL2, MCL4 and MCL <NUM> are denoted in dotted lines. As shown in <FIG>, the nozzle 33a, the nozzle 33b and the nozzle 33c are arranged every other nozzle when projected onto the same projection plane PL1. If a vehicle body FR is coated in the state, the uncoated parts and the coated parts are formed alternately, making the coated vehicle body FR look like discolored or seemingly have recesses.

In addition, as shown in <FIG>, for example, when the baseline MCL2, the baseline MCL5 and the baseline MCL8 are not coated, the nozzle 33a corresponding to the baseline MCL2, the nozzle <NUM> corresponding to the baseline MCL5, and the nozzle 33d corresponding to the baseline MCL8 are clogged. In <FIG>, the uncoated baselines MCL2, MCL5 and the MCL8 are denoted by dotted lines. As shown in <FIG>, the nozzle 33a, the nozzle 33d and the nozzle <NUM> are arranged every two nozzles when projected onto the same projection plane PL1. If a vehicle body FL is coated in the state, the coated vehicle body FR looks discolored due to the uncoated parts.

As shown in <FIG>, for example, when the baseline MCL2, the baseline MCL3, the baseline MCL6 and the baseline MCL <NUM> are not coated, the nozzle 33a corresponding to the baseline MCL2, the nozzle 33f corresponding to the baseline MCL3, the nozzle 33c corresponding to the baseline MCL6 and the nozzle <NUM> corresponding to the baseline MCL7 are clogged. In <FIG>, the uncoated baselines MCL2, MCL3, MCL6 and MCL7 are shown in dotted lines. As shown in <FIG>, the nozzle 33a, the nozzle 33a and the nozzle 33f, and the nozzle 33c and the nozzle <NUM> are adjacent to each other, respectively, when projected onto the same projection plane PL1. If the sample S is coated in the state, the coated vehicle body FR includes strip regions uncoated with the paint.

Here, even if it is indicated that nozzles <NUM> from, for example, the group Gr1 (or G2, G3,. ) eject droplets, coating defect is also determined when there are more than <NUM> uncoated baselines due to clogging. However, considering a number of nozzles <NUM> in each group, constituents of the paint for coating, paint colors, and the like, a number of uncoated baselines upon determination of the coating defect can be determined.

Reference below will be made to the flowchart of <FIG> to describe a processing flow from coating, by the coating system, the test pattern TP to cleaning the coating head unit <NUM>. The flowchart of <FIG> is performed, for example, in a case where a predetermined number of vehicles FR are coating by the painting robot <NUM> immediately before the coating is started on the vehicle body FR, or a case where a certain period of time has elapsed after the coating robot <NUM> is installed in the coating chamber <NUM>.

The management device <NUM> instructs the image processing device <NUM> and the coating robot <NUM> to coat the test pattern TP. In response to receiving the instruction of coating the test pattern TP from the management device <NUM>, the image processing device <NUM> generates coating pattern data based on the test pattern TP and sends the same to the coating robot <NUM>. When the coating pattern data is received, the primary control section <NUM> of the coating robot <NUM> instructs the arm control section <NUM> and the head control section <NUM> to start driving. Upon receiving the instruction, the arm control section <NUM> reads, from the arm memory <NUM>, trajectory data when the test pattern TP is coated, and performs drive control for respective motors M1 - M6 based on the read trajectory data. The head control section <NUM> causes, based on the coating pattern data, the piezoelectric substrate <NUM> of the coating head unit <NUM> to act. In this way, the coating robot <NUM> is used to coat the test pattern TP on the sample S.

If the coating robot <NUM> is used to coat the test pattern TP on the sample S, a content of coating completion is transmitted from the coating robot <NUM> to the management device <NUM>. Upon receiving the content, the management device <NUM> instructs the transport device <NUM> to transport the sample S. The drive control unit <NUM> of the transport device <NUM> stops the drive of the motor M7 after the motor M7 has been driven for a predetermined time. The predetermined time is a time during which a transport time for transporting a sample S carried on the conveyor belt <NUM> to the inspection chamber <NUM>.

The primary control section <NUM> of the control unit <NUM> included in the coating determining device <NUM> determines whether coating defect occurs using the determination image data stored in the memory <NUM> and the camera data. Coating defect determination will be described below. The primary section <NUM> of the control unit <NUM> transmits the determination result of the coating defect to the management device <NUM>.

When the management step device <NUM> determines that coating defect occurs at step S104, the method proceeds to Step S105. On the other hand, when it is determined that no coating defect has occurred, the flow as illustrated in <FIG> is completed.

The management device <NUM> instructs the nozzle cleaning device <NUM> and the coating robot <NUM> to start nozzle cleaning. Upon receiving the instruction, the primary control section <NUM> of the coating robot <NUM> drives the ratable arm <NUM> and the first and second rotatable arms <NUM>, <NUM> such that the position sensor <NUM> senses the position of the coating head unit <NUM> while the coating head unit <NUM> is moved to the cleaning position. Moreover, when the coating head unit <NUM> is moved to the cleaning position, the nozzle cleaning device <NUM> cleans the nozzle forming surface <NUM> of the coating head <NUM>. As a result, the clogging is cleared.

It is not be noted that, at step S105, a new coating head unit <NUM> is substituted, rather than cleaning the nozzle forming surface <NUM> of the coating head <NUM>. When a new coating head unit <NUM> is substituted, the old coating head unit <NUM> can be cleaned at other cleaning site.

Reference now will be made to the flowchart of <FIG> to describe a process of determining coating defect at step S103. The process of determining coating defect at step S103 is performed by the computer <NUM> of the coating determining device <NUM>.

The management device <NUM> instructs the coating determining device <NUM> to use the coating determination on the sample S. Upon receiving the instruction, the primary control section <NUM> of the control unit <NUM> instructs the camera control section <NUM> to capture pictures. At the same time, the light emitting control section <NUM> of the primary control section <NUM> instructs the light source <NUM> to emit light. Upon receiving the instruction, the light emitting control section <NUM> turns on the light source <NUM>. In this way, the sample S coated with the test pattern is illuminated. In addition, the camera control section <NUM> drives the camera section <NUM> to capture the sample S illuminated by the light source <NUM>. The camera data captured by the camera section <NUM> are output to the primary control section <NUM> of the control unit <NUM>.

The image processing section <NUM> of the primary control unit <NUM> performs, for the camera data, processing such as denoising, destraining, brightness adjustment and the like, as well as image processing such as contour extraction processing and the like, and generates processed data.

The extraction section <NUM> of the primary control section <NUM> reads the determination image data <NUM> stored in the memory <NUM>. Besides, when referring to the read determination image data <NUM>, the extraction section <NUM> of the primary control section <NUM> extracts the baselines MCL based on the processed data generated at step S202. The extraction section <NUM> of the primary control section <NUM> generates extraction data indicative of an extraction result.

The determination section <NUM> of the primary control section <NUM> determines, based on the extraction data generated through the processing at step S203, whether uncoated baselines MCL exist for each group as mentioned above. When there is at least one group including, for example, more than <NUM> uncoated baselines MCL, it is determined that coating defect occurs. The number of groups including, for example, more than <NUM> uncoated baselines MCL, can be set appropriately. In the case, at step S105 as described above, the nozzle forming surface <NUM> of the coating head is cleaned.

Therefore, by capturing the coated surface of the sample S coated with the test pattern TP and comparing the same with an image for determination, it is possible to determine whether coating defect has occurred. In addition to this, by determining coating states of the baselines MCL, the positions of the clogged nozzles <NUM> can be determined.

In the above implementation, whether coating defect occurs can be determined based on absence or presence of the baseline MCL on the coated surface of the sample S. For example, a <NUM>-dimensional displacement sensor is used to detect the coating state on the coated surface of the sample S such as a width of the baseline MCL, a splash state of the paint, a thickness of the baseline MCL (i.e., the film thickness of the paint) and the like, and determine the clogged state of the nozzle <NUM> based on the detected result.

Determining whether coating defect has occurred according to the above implementation is performed, for example, either when the coating robot <NUM> is used to coat a predetermined number of vehicle bodies FR prior to the commence of coating the vehicle body FR, or in a predetermined time after the coating robot <NUM> is disposed within the coating chamber <NUM>. Alternatively, the determining whether coating defect is performed based on the coating state of the coated surface of the object to be coated. This will be described with reference to <FIG>.

As shown in <FIG>, a plurality of camera sections <NUM> for capturing the coated vehicle body FR at different positions are disposed in the coating chamber <NUM>. Those camera units <NUM> are connected to the state determining device <NUM>, and controlled and driven by the latter. The plurality of camera sections <NUM> are disposed at a plurality of different positions, which can be fixed or movable.

The state determining device <NUM> generates, based on the camera data acquired by the plurality of camera sections <NUM>, a <NUM> dimensional image of the coated surface of the vehicle body FR, and determines a state of the coated surface of the vehicle body FR. The state determining device <NUM> includes a <NUM>-dimensional image generating section <NUM> and a coated state determining section <NUM>. The coated state determining state <NUM> herein is equivalent to the state determining unit according to the technical solution.

The <NUM>-dimensional image generating section <NUM> generates, based on the camera data acquired by the plurality of camera sections <NUM> and position data of the camera sections <NUM> when acquiring the camera data, <NUM>-dimensional image data on the coated surface of the vehicle body FR.

The coated state determining section <NUM> computes a thickness of a coating film coated over the vehicle body FR using the <NUM>-dimensional image data generated by the <NUM>-dimensional image generating section <NUM> and <NUM>-dimensional data of the vehicle body FR. If there is a part having a coating film with a thickness below a predetermined value, the coating determining device <NUM> is used to determine the coating state.

In the case, upon receiving a content of completion of, for example, the coating performed by the coating robot <NUM> for the vehicle body FR, the state determining device <NUM> drives the camera sections <NUM> to capture the vehicle body FR. In addition, the state determining device <NUM> generates the -dimensional data of the vehicle body FR acquired from the camera sections <NUM>. If there are multiple parts, for example, having coating films each with a thickness below the predetermined value when using the <NUM>-dimensional data of the vehicle body FR, the state determining device <NUM> instructs the management device <NUM> to coat the test pattern TP. Upon receiving the instruction, the management device <NUM> stops coating of the vehicle body FR and instructs to coat the sample S. Therefore, the management device <NUM> functions as an instruction unit according to the technical solution.

In this way, when it is determined that an uneven coating is performed in the coating state where the vehicle body FR is coated, it is instructed to coat the test pattern TP on the sample S. As such, the time when the line coating is stopped is minimized as much as possible, so as to maintain the efficiency for the vehicle body FR.

In the implementation described above, the uncoated baselines MCL are extracted using the determination image data <NUM> and the camera data acquired through image processing. However, the paint is ejected from the nozzle <NUM> based on the clogged state of the nozzle <NUM>. At this time, the amount of droplets is less than the amount of droplets of the paint ejected from the nozzle when there is no clogging, and the baseline MCL becomes thinner. In addition, in a condition that the nozzle <NUM> is clogged, the continuity of the droplets of the paint adhering to the coated surface is abnormal. In the process of determining whether there is clogging, the width of the coated width and continuity of the paint droplets adhered to the coated surface may be taken into consideration. If those are taken into consideration, not only the presence or absence of lockage in the nozzle corresponding baseline MCL can be determined, a degree of clogging in the nozzle can also be derived.

For example, if a baseline becomes thin or curved, it is determined that the corresponding nozzle is in a semi-clogged state. At this time, the nozzle <NUM> determined in a semi-clogged state can be set not to perform the following coating.

It would be appreciated that, if there is a nozzle determined not to perform the following coating, nozzles at the peripheral part of the nozzle can be used for imputation in the following coating.

In the present implementation, the coating determining device <NUM> is the coating determining device <NUM> of the coating head unit <NUM>. The coating head unit <NUM> includes a plurality of nozzles <NUM> for ejecting paints, which eject paints therefrom when moving in a direction. The ejected paints are used to coat the sample S. The coating determining device <NUM> includes a camera section <NUM> for acquiring an image of the coated sample S, and a determination section <NUM> for determining, based on the image acquired by the camera unit <NUM>, whether coating the sample S is normally performed.

As such, it cannot only be determined, based on the image of the coated sample S, whether the sample S is normally coated, but respective states (presence or absence of clogged pores, a clogging degree of a pore and the like) of the plurality of nozzles <NUM> included in the coating head unit <NUM> can also be obtained. In addition, a reliable detection on whether the sample S can be normally coated can be performed in a short time. When the respective states of the plurality of nozzles <NUM> of the coating head unit <NUM> are obtained, the coating quality for the vehicle body FR can be improved.

Besides, there is provided an extraction section <NUM> for extracting, from the image of the coated sample S, coating defect performed for the sample S. When the extraction section <NUM> extracts coating defect in the sample, the determination section <NUM> determines the nozzles in the plurality of nozzles <NUM> included in the coating head unit <NUM> having an ejecting defect for the paint.

Coating missing, namely no paint coating performed, or position offsets of the ejected paints can be determined, making it easy to determine the positions of the nozzles <NUM> in the plurality of nozzles <NUM> included in the coating head unit <NUM> having an ejecting defect for the paint.

The coating head unit <NUM> includes a head control section <NUM> for controlling paint ejection at the plurality of nozzles <NUM> for each nozzle, which cooperates with the coating head unit <NUM> to move in a direction. The plurality of nozzles <NUM> included in the coating head unit <NUM> are used to apply, to the sample S, the test pattern TP for determining whether paint ejection failure occurs, and the determination section <NUM> determines, based on the image of the sample S coated with the test pattern TP, whether coating the sample S is implemented normally.

Whether the coating of the coating head unit <NUM> is performed normally is determined using, for example, the image of the coated test pattern TP. Since the test pattern TP is used to determine whether the nozzles <NUM> are clogged, the clogged states of the plurality of nozzles <NUM> can be reliably detected (obtained).

The coating head unit <NUM> is provided with a plurality of nozzle rows 34a, 34b in a direction orthogonal to a direction, where the nozzle rows 34a, 34b include a predetermined number of nozzles <NUM> arranged in an inclined direction relative to the direction. The test pattern TP at least includes a plurality of baselines MCL configured in a <NUM>-dimensional shape and arranged along a direction. When the coating head <NUM> moves in a direction, the head control section <NUM>, while switching the nozzles, causes all the nozzles <NUM> to respectively perform such an action that a certain nozzle in the predetermined number of nozzles <NUM> respectively included in the plurality of nozzle rows 34a, 34b ejects the paint continuously to coat the sample S with a plurality of baselines MCL.

In the present disclosure, while the coating head unit <NUM> is moving in a direction, the paint is ejected from the each nozzle <NUM> to coat a workpiece as the object to be coated. A plurality of coating heads <NUM> of the plurality of nozzle rows 34a, 34b disposed in a direction orthogonal to the direction are used, where the nozzle rows 34a, 34b respectively include a predetermined number of nozzles <NUM> arranged in a direction inclined relative to the movement direction of the coating head unit <NUM>, and a plurality of baselines MCL respectively corresponding to the nozzles <NUM> of the coating head <NUM> are set as a test pattern TP. As such, by determining the coating state of each baseline MCL, it is easy to determine whether there is a nozzle <NUM> causing coating defect, and obtain the coated state of the vehicle body FR.

In the image of the test pattern TP acquired through the camera section <NUM>, if coating defect is performed for a predetermined number of baselines MCL in the baselines MCL formed by a certain nozzle in a predetermined number of nozzles <NUM> included in the same nozzle row 34a, 34b, the determination section <NUM> determines that the sample S coated using the coating head <NUM> is not normally coated.

For example, the state where coating defect is performed for more than the predetermined number of baselines MCL is a state where the FR cannot be uniformly coated. The vehicle body FR in the coated state is considered as a coating failure and thus cannot be used. Therefore, by obtaining the coated state of the sample S coated using the coating head unit <NUM><NUM>, it is possible to avoid poorly coated vehicle bodies FR.

In addition, there are further provided: at least one camera section <NUM> that captures the vehicle body VR at a plurality of different positions; a <NUM>-dimensional image generating section <NUM> that generates, based on the image captured by the at least one camera section <NUM>, a <NUM>-dimensional image of the vehicle body FR coated by the coating head <NUM>; and a coated state determining section <NUM> that determines the coated state of the vehicle body FR using the <NUM>-dimensional image of the vehicle body FR generated by the <NUM>-dimensional image generating section <NUM>.

In this way, by acquiring the <NUM>-dimensional image of the coated vehicle body FR, it is possible to obtain the coating state of the coated surface of the vehicle body FR, i.e., it is possible to determine whether uneven coating is carried out. For example, if uneven coating is carried out, the nozzle <NUM> corresponding to the uneven part among the plurality of nozzles <NUM> included in the coating head unit <NUM> can be determined. In addition, the clogged state of the pore of the each nozzle <NUM> can be determined based on the unevenness of the coating.

Moreover, the coated state determining section <NUM> further includes a management device <NUM> that determines, using the <NUM>-dimensional image, whether the thickness of the paint coated over the sample S is below a predetermined thickness, and if determining that the thickness of the coating is below a predetermined thickness, the coted state determining section <NUM> instructs to coat the sample S with a test pattern TP for determining presence or absence of an ejecting defect for the paint.

As such, when the <NUM>-dimensional image is coated unevenly on the coated surface of the vehicle body FR, it is instructed to coat the test pattern TP on the sample S, making it possible to appropriately detect the nozzle <NUM> among the plurality of nozzles <NUM> included in the coating head <NUM> having an ejecting defect for the paint caused by pore clogging and the like.

There are further provided: a coating head unit <NUM> including a plurality of nozzles <NUM>; a coating robot <NUM> that is disposed within a coating chamber <NUM> subjected to an explosion-poof treatment and can cause the coating head unit <NUM> to move along the sample S in a direction; the coating determining device <NUM> described above; and a nozzle cleaning device <NUM> for cleaning a plurality of nozzles <NUM> included in the coating head <NUM>, the nozzle cleaning device <NUM> cleaning the plurality of nozzles <NUM> included in the coating head <NUM> when the coating determining device <NUM> determines that the sample S is not normally coated.

Accordingly, when the coating determining device <NUM> determines that it is unable to normally coat the sample S, the plurality of nozzles included in the coating head <NUM> are cleaned to remove the clogging of the nozzle <NUM> and thus maintain the coating quality for the vehicle body FR.

At this time, a workpiece includes the sample S coated with a test pattern in the coating determining device <NUM> for determining whether the coating the vehicle body FR can be performed normally. The coating determining device <NUM> is disposed outside the coating chamber <NUM> and further includes a transport device <NUM> for transporting the sample S coated with a test pattern by the coating head unit <NUM> to the coating determining device <NUM>.

Claim 1:
A coating determining device (<NUM>) of a coating head (<NUM>) for determining a coating state of the coating head (<NUM>), comprising:
a coating head having a plurality of nozzles (<NUM>) for ejecting paint and being configured to eject the paint out of the nozzles (<NUM>) so as to coat a workpiece with the ejected paint while moving in a direction, the coating determining device (<NUM>) comprising
an image acquiring unit for acquiring an image of the coated workpiece; and
a determination unit for determining, based on the image acquired by the image acquiring unit, whether coating the workpiece is implemented normally,
wherein:
the coating head (<NUM>) comprises a control unit (<NUM>) for controlling ejection of the paint at the plurality of nozzles (<NUM>) for each nozzle,
the control unit (<NUM>) cooperates with the coating head (<NUM>) to move in a direction, and applies to the workpiece with a pattern for determination for determining whether there is an ejecting defect for the paint using the plurality of nozzles (<NUM>) comprised by the coating head (<NUM>), and
the determining unit is configured to determine, based on an image of the workpiece coated with the pattern for determination, whether coating the workpiece is implemented normally and to send to a management device (<NUM>) a determination result as to whether coating defect occur; and
the coating head (<NUM>) is provided with a plurality of nozzle rows (34a, 34b) in a direction orthogonal to the direction, the nozzle rows (34a, 34b) each including a predetermined number of nozzles (<NUM>) arranged in a direction inclined relative to the direction,
the pattern for determination at least comprises a plurality of baselines (MCL; SCL) configured in a <NUM>-dimensional shape and extending along the direction, and
when the coating head (<NUM>) is moving in a direction, the control unit (<NUM>), while switching the nozzles (<NUM>), coats the plurality of baselines (MCL; SCL) onto the workpiece by continuously ejecting the paint baselines from any one of the predetermined number of nozzles (<NUM>) comprised by each of the plurality of nozzle arrays.