Patent Description:
Robot painting using robots predominates in painting lines for vehicles such as automobiles. In the robot painting, a painting machine (a rotary atomization type painting machine) having a rotary atomization type painting head mounted at a front end of an articulated robot is used, but it is proposed to paint the vehicles by using an inkjet-type vehicle painting machine. Such an inkjet-type painting machine has, for example, structures shown in Patent Literature <NUM> to <NUM>.

Patent Literature <NUM> discloses that a painting width is automatically adjusted by adjusting the angle of a rotation direction of a painting head in accordance with the shape of a painting location of a vehicle, which serves as a painting object. In addition, the same content is also disclosed in Patent Literature <NUM> and Patent Literature <NUM>. Patent Literature <NUM> describes printing an image onto a curved surface of a three-dimensional article, while Patent Literature <NUM> describes a head structure having a plurality of nozzles arrayed two-dimensionally for reducing crosstalk.

However, in the structures disclosed in Patent Literature <NUM> to <NUM>, the painting width is adjusted by rotating the painting head. In general, however, in the painting head, under the premise of an advancement direction being perpendicular to a long side direction of the painting head corresponding to the painting width, a plurality of nozzles constitute a nozzle column, and a large number of the nozzle columns are provided. Therefore, when the painting head is rotated to perform painting, there may be cases where paint droplets ejected from predetermined nozzles of a certain nozzle column overlap with the paint droplets ejected from predetermined nozzles of other nozzle columns at a specific location, but no such overlap occurs elsewhere. In particular, the presence or absence of such overlap of the paint droplets becomes remarkable when the nozzle column is inclined relative to the advancement direction of the painting head. Therefore, it is preferable to perform painting in a state where the long side direction of the painting head is kept perpendicular to the advancement direction of the painting head.

However, for example, represented by the roof of the vehicle, the width of the painting location of the vehicle is not constant, and the height is not constant either. Therefore, when the painting is performed in the state where the long side direction of the painting head is kept perpendicular relative to the advancement direction of the painting head, it is relatively difficult to form a uniform painting film thickness relative to the painting location represented by the roof of the vehicle.

The present invention is made in view of the above situations and is intended to provide an inkjet-type vehicle painting machine and an inkjet-type vehicle painting method, which may form a uniform painting film thickness relative to a painting location represented by the roof of a vehicle, when painting is performed in a state where a long side direction of a nozzle head corresponding to a painting width is kept perpendicular relative to an advancement direction of a painting head.

In order to solve the above problems, according to a first aspect of the present invention, an inkjet-type vehicle painting machine is provided, which is used for performing painting by ejecting paint from nozzles onto a vehicle located on a painting line. The inkjet-type vehicle painting machine is characterized by including: a nozzle head having a plurality of nozzles; a robot arm capable of assembling the nozzle head to a front end portion and moving the assembled nozzle head; an arm control portion for controlling the operation of the robot arm; a head control portion for controlling the driving of the nozzle head; and painting data forming means for forming, based on a painting range corresponding to a vehicle to be painted, painting data that is used for controlling the driving of the nozzle head by means of the head control portion, wherein a plurality of nozzle columns composed of the nozzles are arranged obliquely relative to a long side direction of the nozzle head, the nozzle column is provided with a first nozzle column that is located on one side in a scanning direction of the nozzle head, and a second nozzle column that is located on the other side in the scanning direction, the first nozzle column and the second nozzle column are configured in a state where the droplets ejected from the nozzles in the second nozzle column are ejected in the middle of the droplets ejected from adjacent nozzles in the first nozzle column when the long side direction of the nozzle head is orthogonal to the scanning direction, the painting data forming means create trajectory data for driving the robot arm to move the nozzle head, and forms, based on the trajectory data, posture data for keeping the long side direction of the nozzle head perpendicular relative to a main scanning direction of the nozzle head.

In addition, in the above invention, preferably, the painting data forming means take a location on a vehicle side where the distance between the vehicle and a nozzle ejection surface in the painting width of the nozzle head is the closest as a reference location, and create the trajectory data at a position higher than the reference location by a predetermined height.

In addition, in the above invention, preferably, the painting data forming means form, before forming the trajectory data, a painting three-dimensional model for the painting range per painting range of the vehicle to be painted, and forms divided painting data actually corresponding to the painting width of the nozzle head based on the painting three-dimensional model, the trajectory data and the posture data, and the divided painting data includes an overlapping portion that overlaps with adjacent divided painting data.

In addition, in the above invention, preferably, the painting data forming means form the posture data, so that in a width direction of the vehicle, the nozzle head is inclined at an inclination angle the same as the inclination angle of the painting location of the vehicle, which is located at a location opposed to the center of the nozzle head in the long side direction.

In addition, in the above invention, preferably, the painting data forming means form the posture data, so that in the long side direction of the vehicle, the nozzle head is inclined at an inclination angle the same as the inclination angle of the painting location of the vehicle, which is located at a location opposed to the center of the nozzle head in a short side direction.

In addition, in the above invention, preferably, the painting data forming means increase the concentration of the divided painting data according to the inclination angle of the location opposed to the center of the nozzle head in the short side direction.

In addition, in the above invention, preferably, the painting data forming means form, before forming the trajectory data, a painting three-dimensional model for the painting range per painting range of the vehicle to be painted, forms two-dimensional painting data for painting the vehicle based on the painting three-dimensional model, forms divided painting data actually corresponding to the painting width of the nozzle head based on the two-dimensional painting data, and forms the trajectory data based on the divided painting data.

In order to solve the above problems, according to a second aspect of the present invention, an inkjet-type vehicle painting method is provided, including a nozzle head having a plurality of nozzle columns composed of nozzles, wherein the nozzle column is arranged obliquely relative to a long side direction of the nozzle head, the nozzle column is provided with a first nozzle column that is located on one side in a scanning direction of the nozzle head, and a second nozzle column that is located on the other side in the scanning direction, the first nozzle column and the second nozzle column are configured in a state where the droplets ejected from the nozzles in the second nozzle column are ejected in the middle of the droplets ejected from adjacent nozzles in the first nozzle column when the long side direction of the nozzle head is orthogonal to the scanning direction, moreover, trajectory data is formed, the trajectory data is used for driving a robot arm, which assembles the nozzle head at a front end portion, to move the nozzle head, and based on the trajectory data, posture data is formed for keeping the long side direction of the nozzle head perpendicular relative to a main scanning direction of the nozzle head.

According to the present invention, the inkjet-type vehicle painting machine and the inkjet-type vehicle painting method are provided, which may form the uniform painting film thickness relative to the painting location represented by the roof of the vehicle, when painting is performed in the state where the long side direction of the nozzle head corresponding to the painting width is kept perpendicular relative to the advancement direction of the painting head.

Hereinafter, the inkjet-type vehicle painting machine and the inkjet-type vehicle painting method involved in various embodiments of the present invention will be illustrated based on the drawings.

The inkjet-type vehicle painting machine and the inkjet-type vehicle painting method in the present embodiment are a method for "painting" a painting target object relative to a vehicle or a vehicle component (hereinafter, the vehicle component becoming a portion of the vehicle is also regarded as the "vehicle" for description) located on a painting line in an automobile manufacturing plant, so as to form a painting film on the surface of the painting target object to provide protection and beauty to the surface thereof. Therefore, it is necessary to perform painting with desired painting quality within a certain period of time relative to a vehicle moving along the painting line every predetermined time.

In addition, in order to paint the vehicle, it is necessary to perform painting faster on a vehicle to be painted at the same action as a vehicle that has already been painted. Therefore, a multi-axis robot arm, which will be described later, needs to perform the same action relative to many vehicles, and a nozzle head unit <NUM> needs to move while maintaining a state of being opposed to the vehicle at a short distance. In addition, the nozzle head unit <NUM> is installed on a front end side of the robot arm, but a loadable weight cannot be greatly increased if a moment when the robot arm is extended is considered. In addition, as described above, since the vehicles move along the painting line one after another, it is necessary for the vehicle painting machine to perform the painting as quickly as possible. That is, the vehicle painting machine in the present embodiment is used under the particularity of such vehicle painting.

In addition, with regard to the inkjet-type vehicle painting machine and the inkjet-type vehicle painting method in the present embodiment, not only the above painting film may be formed, but also various appearance designs and images may be formed relative to the painting target object such as a vehicle and a vehicle component.

<FIG> is a schematic diagram showing an overall structure of an inkjet-type vehicle painting machine <NUM> involved in a first embodiment of the present invention. <FIG> is a diagram showing a schematic structure of the vehicle painting machine <NUM>. As shown in <FIG> and <FIG>, the vehicle painting machine <NUM> is provided with a painting robot <NUM>, a paint supply portion <NUM>, and a nozzle head unit <NUM>.

As shown in <FIG>, the painting robot <NUM> takes a base <NUM>, a leg portion <NUM>, a rotating shaft portion <NUM>, a rotating arm <NUM>, a first rotating arm <NUM>, a second rotating arm <NUM>, a wrist portion <NUM>, and motors M1 to M6 for driving them as main components. In addition, a portion from the rotating shaft portion <NUM> to the wrist portion <NUM> corresponds to a robot arm, but other portions excluding, for example, the leg portion <NUM>, may also correspond to the robot arm.

Among these, the base <NUM> is a portion arranged at an arrangement location such as the ground, but the base <NUM> may also be able to travel relative to the arrangement location. In addition, the leg portion <NUM> is a portion erected from the base <NUM> toward an upper portion. In addition, a joint portion may also be arranged between the leg portion <NUM> and the base <NUM>, so that the leg portion <NUM> may rotate relative to the base <NUM>.

In addition, the rotating shaft portion <NUM> is arranged at an upper end of the leg portion <NUM>. The rotating arm <NUM> is installed on the rotating shaft portion <NUM> in a freely rotatable state. In addition, the rotating arm <NUM> is driven by the motor M1 to rotate, but as such a motor, an electric motor or a pneumatic motor may be used. In addition, when the vehicle painting machine <NUM> is arranged in an explosion-proof area and an electric motor is used, it is preferable to have an explosion-proof structure for increasing an internal pressure in a shell of the rotating shaft portion <NUM> (the situation is the same in the following motors M2 to M6). However, when the vehicle painting machine <NUM> is arranged in a place other than the explosion-proof area, the above-mentioned explosion-proof structure may not be provided. In addition, at least one of the rotating arm <NUM>, the first rotating arm <NUM>, the second rotating arm <NUM>, the wrist portion <NUM> and a chuck portion <NUM> may have such an explosion-proof structure.

In addition, one end side of the first rotating arm <NUM> is installed on the rotating arm <NUM> in a rotatable state. In addition, the motor M2 that drives the first rotating arm <NUM> to rotate relative to the rotating shaft portion <NUM> may be accommodated in the shell of the rotating arm <NUM>, and may also be accommodated in the shell of the first rotating arm <NUM>.

In addition, one end side of the second rotating arm <NUM> is installed on the other end side of the first rotating arm <NUM> via a shaft portion in a freely swingable state. The motor M3 that drives the second rotating arm <NUM> to rotate relative to the first rotating arm <NUM> may be accommodated in the shell of the first rotating arm <NUM>, and may also be accommodated in the shell of the second rotating arm <NUM>.

The wrist portion <NUM> is installed on the the other end side of the second rotating arm <NUM>. The wrist portion <NUM> may perform a rotational movement around a plurality of (for example, three) shaft portions with different orientations as the center. Thereby, the orientation of the nozzle head unit <NUM> may be controlled with high precision. In addition, several shaft portions may be provided as long as the number is two or more.

The motors M4 to M6 are provided in order to enable such a wrist portion <NUM> to perform the rotational movement with the each shaft portion as the center. In addition, the motors M4 to M6 are accommodated in the shell of the second rotating arm <NUM>, but they may also be accommodated in other locations.

In addition, the nozzle head unit <NUM> is installed on the arm portion <NUM> by means of a bracket portion that is not shown in the figure. That is, the nozzle head unit <NUM> is detachably arranged on the arm portion <NUM> by means of the bracket portion.

In addition, the vehicle painting machine <NUM> equipped with the rotating shaft portion <NUM>, the rotating arm <NUM>, the first rotating arm <NUM>, the second rotating arm <NUM>, the wrist portion <NUM>, and the motors M1 to M6 for driving them is a robot that may be driven by <NUM> axes. However, the vehicle painting machine <NUM> may be a robot that is driven by any number of axes greater than <NUM>.

Next, the nozzle head unit <NUM> will be described. The nozzle head unit <NUM> is installed on the wrist portion <NUM> by means of the chuck portion <NUM>. As shown in <FIG>, the nozzle head unit <NUM> is provided with a head cover which is not shown in figure, and various structures are built in the head cover. In addition, examples of the structures built in the head cover include a paint circulation path, that is, a head side circulation path (not shown in the figure), a head control portion <NUM>, etc..

<FIG> is a diagram showing a front view state of a nozzle ejection surface <NUM> for ejecting paint from the nozzle head unit <NUM>. In <FIG> is a partial top view showing the configuration of each nozzle <NUM> on the nozzle ejection surface <NUM>, <FIG> shows a result of ejecting paint from each nozzle <NUM>, and <FIG> shows a driving moment of each nozzle <NUM>. In addition, in <FIG>, for convenience of description, a secondary scanning direction (an X direction) is shown in a state where it is greatly stretched. For example, on the leftmost side of a nozzle head <NUM> in <FIG>, there are a nozzle column <NUM> composed of a total of <NUM> nozzles <NUM> on a depth side of a paper surface of <FIG> and a nozzle column <NUM> composed of a total of <NUM> nozzles <NUM> on a front side of the paper surface of <FIG>, but a state corresponds to <FIG>, where the two nozzle columns <NUM> are taken out, a main operation direction (the X direction) remains unchanged without being stretched, and the secondary scanning direction (the X direction) is greatly stretched.

As shown in <FIG> and <FIG>, the nozzle ejection surface <NUM> is provided with a plurality of nozzle columns <NUM> in which the nozzles <NUM> are arranged in a column in a direction that is inclined relative to a long side direction of the nozzle head unit <NUM>. In addition, in <FIG>, a longitudinal axis represents time (driving moment), and a horizontal axis represents positions of a total of <NUM> nozzles 54A and a total of <NUM> nozzles 54B in the X direction. In addition, in the above description, a long side of the nozzle head unit <NUM> refers to a longer direction (a lateral width direction) of the nozzle head in <FIG>.

In the present embodiment, such a nozzle column <NUM> is provided with a first nozzle column 55A located on one side (a Y2 side) of the main scanning direction (a Y direction) and a second nozzle column 55B located on the other side (a Y1 side) of the main scanning direction. In the first nozzle column 55A and the second nozzle column 55B, the nozzle column located on the side (the left side) closest to the secondary scanning direction of <FIG> is respectively shown in <FIG> as a first nozzle column 55A1 and a second nozzle column 55B1.

Here, if the nozzles 54A, 54B in the first nozzle column 55A1 and the second nozzle column 55B1 are projected on a straight line (a projection straight line PL) along the secondary scanning direction of <FIG>, the first nozzle 54B11 counted starting from the Y1 side of the second nozzle column 55B1 is located on the projection straight line PL between the first nozzle 54A11 and the second nozzle 54A12 counted starting from the Y1 side of the first nozzle column 55A1. In addition, the second nozzle 54B12 counted starting from the Y1 side of the second nozzle column 55B1 is located between the second nozzle 54A12 and the third nozzle 54A13 counted starting from the Y1 side. Hereinafter, similarly, between adjacent nozzles 54A in the first nozzle column 55A, the nozzles 54B in the second nozzle column 55B are located on the above projection straight line PL.

Therefore, in a state where the nozzle head unit <NUM> is scanning, by controlling the ejection moment of the droplets ejected from the respective nozzles 54A and 54B as shown in <FIG>, the droplets may land on the straight line in the secondary scanning direction as shown in <FIG>. As it were, the nozzle columns <NUM> are configured such that the landing positions of the droplets of adjacent nozzle columns <NUM> are staggered by a half pitch. Thereby, it is possible to increase the point density while painting.

However, as shown in <FIG>, a single nozzle head <NUM> exists on the nozzle ejection surface <NUM>. However, a head group composed of a plurality of nozzle heads <NUM> may also exist on the nozzle ejection surface <NUM>. In this case, as an example, as shown in <FIG>, a structure in which a plurality of nozzle heads <NUM> are aligned and are configured in a staggered manner may be cited, but the configuration of the nozzle heads <NUM> of the head group may be not staggered.

<FIG> is a diagram showing an overall structure for supplying paint to each nozzle <NUM>. <FIG> is a cross-sectional view showing a structure in the vicinity of a column direction supply flow path <NUM>, a nozzle pressurizing chamber <NUM> and a column direction discharge flow path <NUM>. As shown in <FIG> and <FIG>, the nozzle head <NUM> is provided with a supply side large flow path <NUM>, the column direction supply flow path <NUM>, the nozzle pressurizing chamber <NUM>, the column direction discharge flow path <NUM>, and a discharge side large flow path <NUM>. The supply side large flow path <NUM> is a flow path for supplying paint from a supply path <NUM> of a head side circulation path described later. In addition, the column direction supply flow path <NUM> is a flow path in which the paint in the supply side large flow path <NUM> diverges.

In addition, the nozzle pressurizing chamber <NUM> is connected to the column direction supply flow path <NUM> by means of a nozzle supply flow path 59a. As a result, the paint is supplied to the nozzle pressurizing chamber <NUM> from the column direction supply flow path <NUM>. The nozzle pressurizing chamber <NUM> is provided corresponding to the number of nozzles <NUM> and may eject the paint inside from the nozzle <NUM> by using a driving element described later.

In addition, the nozzle pressurizing chamber <NUM> is connected to the column direction discharge flow path <NUM> by means of a nozzle ejection flow path 59b. Therefore, the paint that is not ejected from the nozzle <NUM> is discharged from the nozzle pressurizing chamber <NUM> via the nozzle ejection flow path 59b toward the column direction discharge flow path <NUM>. In addition, the column direction discharge flow path <NUM> is connected to the discharge side large flow path <NUM>. The discharge side large flow path <NUM> is a flow path in which the paint ejected from various column direction discharge flow paths <NUM> merges. The discharge side large flow path <NUM> is connected to a return path <NUM> of the head side circulation path.

According to such a structure, the paint supplied from the supply path <NUM> of the head side circulation path is ejected from the nozzle <NUM> by means of the supply side large flow path <NUM>, the column direction supply flow path <NUM>, the nozzle supply flow path 59a and the nozzle pressurizing chamber <NUM>. In addition, the paint that is not ejected from the nozzle <NUM> returns from the nozzle pressurizing chamber <NUM> to the return path <NUM> of the head side circulation path by means of the nozzle ejection flow path 59b, the column direction discharge flow path <NUM> and the discharge side large flow path <NUM>.

In addition, in the structure shown in <FIG>, one column direction supply flow path <NUM> is configured to correspond to one column direction discharge flow path <NUM>. However, it may also be configured such that one column direction supply flow path <NUM> corresponds to a plurality of (for example, two) column direction discharge flow paths <NUM>. In addition, it may also be configured such that a plurality of column direction supply flow paths <NUM> correspond to one column direction discharge flow path <NUM>.

In addition, as shown in <FIG>, a piezoelectric substrate <NUM> is configured on a top surface (the surface on an opposed side of the nozzle <NUM>) of the nozzle pressurizing chamber <NUM>. The piezoelectric substrate <NUM> is provided with two piezoelectric ceramic layers 63a and 63b, which serve as piezoelectric bodies, and is also provided with a common electrode <NUM> and individual electrodes <NUM>. The piezoelectric ceramic layers 63a and 63b are members that may expand and contract by applying a voltage from the outside. As such piezoelectric ceramic layers 63a and 63b, ceramic materials with high dielectricity such as lead zirconate titanate (PZT) series, NaNbO3 series, BaTiO3 series, (BiNa)NbO3 series, and BiNaNb5O15 series may be used.

In addition, as shown in <FIG>, the common electrode <NUM> is configured between the piezoelectric ceramic layer 63a and the piezoelectric ceramic layer 63b. In addition, a surface electrode (not shown in the figure) for the common electrode is formed on an upper surface of the piezoelectric substrate <NUM>. The common electrode <NUM> and the surface electrode for the common electrode are electrically connected by a through conductor which is not shown in figure and exists on the piezoelectric ceramic layer 63a. In addition, the individual electrodes <NUM> are respectively configured at locations opposed to the nozzle pressurizing chamber <NUM>. Further, a portion of the piezoelectric ceramic layer 63a sandwiched between the common electrode <NUM> and the individual electrode <NUM> is polarized in a thickness direction. Therefore, if a voltage is applied to the individual electrode <NUM>, the piezoelectric ceramic layer 63a is deformed due to a piezoelectric effect. Therefore, when a predetermined driving signal is applied to the individual electrode <NUM>, the piezoelectric ceramic layer 63b relatively fluctuates in such a way that the volume of the nozzle pressurizing chamber <NUM> is reduced, thereby ejecting the paint.

In addition, in the structure shown in <FIG>, the common electrode <NUM> is configured on the top surface of the nozzle pressurizing chamber <NUM>, but it is not limited to this structure. For example, as shown in <FIG>, a structure in which the common electrode <NUM> is configured on a side face of the nozzle pressurizing chamber <NUM> may also be used, and in addition, any structure may be used as long as the paint may be ejected from the nozzle <NUM> well.

Next, a control mechanism of the vehicle painting machine <NUM> of the present embodiment will be described. The control mechanism is provided with an image processing portion <NUM>, an arm control portion <NUM>, a paint supply control portion <NUM>, a head control portion <NUM>, and a main control portion <NUM>. In addition, the image processing portion <NUM>, the arm control portion <NUM>, the paint supply control portion <NUM>, the head control portion <NUM> and the main control portion <NUM> are composed of a CPU, a memory (an ROM, an RAM, a non-volatile memory or the like), and other elements. In addition, the memory stores programs and data, which are used for executing desired control.

Among these, the image processing portion <NUM> forms a three-dimensional model (painting three-dimensional model) based on CAD data corresponding to a painting range of the vehicle. In addition, the image processing portion <NUM> forms, based on trajectory data D1 formed by the arm control portion <NUM> described later and the above painting three-dimensional model, two-dimensional divided painting data corresponding to the painting of the nozzle head <NUM> along the trajectory data D1.

In addition, the image processing portion <NUM> and the arm control portion <NUM> correspond to painting data forming means, but may also correspond to at least one painting data forming means that includes at least one excluding these portions (for example, the head control portion <NUM>, the main control portion <NUM>, and the like).

In addition, the arm control portion <NUM> is a portion that controls the driving of the above motors M1 to M6. The arm control portion <NUM> is provided with a memory <NUM>, and the memory <NUM> stores the trajectory data D1 that is formed considering robot instruction of a painting width that the nozzle head <NUM> may paint, and posture data related to the posture of the nozzle head <NUM>. Moreover, the arm control portion <NUM> controls the driving of the motors M1 to M6 based on the trajectory data D1 and the posture data stored in the memory <NUM> and the image processing in the image processing portion <NUM>. By means of the control, the nozzle head <NUM> may pass through a desired position for performing painting at a desired speed, or stop at a predetermined position. In addition, the memory <NUM> may also be provided on the vehicle painting machine <NUM>. However, the memory <NUM> may also exist outside the vehicle painting machine <NUM>, and information may be received and sent relative to the memory <NUM> by means of a wired or wireless communication mechanism.

In addition, the paint supply control portion <NUM> is a portion that controls the supply of the paint to the nozzle head <NUM>, and specifically controls the operation of a pump, a valve and the like included in the paint supply unit <NUM>. At this time, preferably, the paint supply control portion <NUM> controls the operation of the above pump and the valve by supplying the paint at a constant pressure (one example of the constant pressure is a fixed amount) relative to the nozzle head <NUM>.

In addition, the head control portion <NUM> is a portion that controls the operation of the piezoelectric substrate <NUM> in the nozzle head unit <NUM> based on the image processing in the image processing portion <NUM>. When the head control portion <NUM> reaches a predetermined position of the trajectory data D1 according to a mechanism that detects the position of a sensor <NUM> or the like described later, it controls the ejection of the paint based on the divided painting data corresponding to the position. In addition, in this case, the driving frequency of the piezoelectric substrate <NUM> is controlled in a manner of ensuring a uniform film thickness of the vehicle, so as to control the number of points (the number of droplets) ejected from the nozzle <NUM>, or the voltage applied to the piezoelectric substrate <NUM> is controlled to control the size of the droplets ejected from the nozzle <NUM>.

In addition, the main control portion <NUM> is a portion that sends a predetermined control signal to the arm control portion <NUM>, the paint supply control portion <NUM> and the head control portion <NUM> by performing painting relative to the painting object by means of the cooperation of the motors M1 to M6, the paint supply portion <NUM> and the piezoelectric substrate <NUM>.

In addition, in order to keep the nozzle ejection surface <NUM> of the nozzle head <NUM> parallel to the painting surface under the control of the arm control portion <NUM>, various sensors <NUM> are connected to the painting robot <NUM>. Examples of the sensor <NUM> include an angular velocity sensor, an acceleration sensor, an image sensor, a ToF (Time of Flight) sensor or the like, but other sensors may also be used.

Next, based on <FIG>, a painting method for painting painting objects such as vehicles and vehicle components in the vehicle painting machine <NUM> having the above-mentioned structure will be described. <FIG> is a flow diagram showing an outline of the painting method using the vehicle painting machine <NUM> of the present embodiment. First, the image processing portion <NUM> of the vehicle painting machine <NUM> forms a three-dimensional model (painting three-dimensional model) based on CAD data of the vehicle (step S11). In the painting three-dimensional model, a three-dimensional model of a location that is actually painted except for a location that is not to be painted is formed.

Next, the arm control portion <NUM> forms trajectory data D1 based on the above painting three-dimensional model (step S12). The trajectory data D1 may also be formed by considering robot instruction of a painting width that the nozzle head <NUM> may paint, or the trajectory data D1 is automatically generated. When such trajectory data D1 is formed, the trajectory data D1 is formed such that adjacent painting areas have a small overlapping portion L2, that is, a state in which the painting width L1 includes the overlapping portion L2. In addition, when the painting range in the vehicle is known in advance, the trajectory data D1 may also be formed without depending on the painting three-dimensional model, but, for example, depending on the CAD data.

In addition, step S12 may be performed first, and then step S11 may be performed. That is, after the trajectory data D1 is formed in the arm control portion <NUM>, the painting three-dimensional model may be formed at a position lower than the trajectory data D1 by a predetermined distance.

Here, a height image when the trajectory data D1 is formed is as shown in <FIG>. As shown in <FIG>, there may be a height difference <NUM> in the vehicle <NUM> that serves as an actual painting target. Therefore, when the trajectory data D1 is formed, a location (the height difference <NUM> or the like) on a vehicle <NUM> side where the distance between the vehicle <NUM> side and the nozzle ejection surface <NUM> in the painting width L1 is the closest is taken as a reference location P1, and the trajectory data D1 is created at a position higher than the reference location P1 by a predetermined height, so as to prevent the interference between the height difference <NUM> and the nozzle head <NUM>.

In addition, preferably, in the case of the overlooking trajectory data D1 as shown in <FIG>, the trajectory data D1 is linear. However, the trajectory data D1 may also have a curved portion within a range in which the overlapping portion L2 of the divided painting data D3 described later is not lower than a lower limit.

Next, the arm control portion <NUM> forms posture data in a manner corresponding to the trajectory data D1 (step <NUM>). In addition, the posture data may also be formed together with the trajectory data D1. As shown in <FIG>, the posture data is formed such that the long side direction (the lateral width direction) T of the nozzle head <NUM> is kept perpendicular relative to the main scanning direction S (the advancement direction) of the nozzle head <NUM>. By forming such posture data, as shown in <FIG>, it is possible to eject the paint on the painting surface at equal intervals.

Here, <FIG> shows an image when the long side direction T of the nozzle head <NUM> is not kept perpendicular relative to the main scanning direction S of the nozzle head <NUM> (when the long side direction T is inclined relative to the main scanning direction S). As shown in <FIG>, if the long side direction T of the nozzle head <NUM> is inclined, the landing positions of the droplets will be in a non-uniform state. That is, a portion where the droplets overlap each other and a portion where the droplets do not overlap and leave gaps are formed. Such overlaps and gaps of the droplets may cause poor painting. Therefore, the posture data is formed such that the long side direction T of the nozzle head <NUM> is kept perpendicular relative to the main scanning direction S of the nozzle head <NUM>.

In addition, the posture data is formed so that in a section (cross section) in the width direction of the vehicle, at least a portion of the nozzle ejection surface <NUM> of the nozzle head <NUM> maintains a state of being parallel to the cross section of the vehicle that serves as the painting target. For example, as shown in <FIG>, the posture data is formed, such that in the case where the portion of the painting width is inclined at a predetermined angle θ1 relative to the horizontal plane like the end side in the width direction of the vehicle, the nozzle head <NUM> is also inclined by the inclination amount.

In addition, for the posture data, preferably, the posture data is formed such that, as shown in <FIG>, for example, when the inclination angle of the painting surface at the location opposed to the center of the long side direction T of the nozzle ejection surface <NUM> is the angle θ1, the long side direction T of the nozzle head <NUM> is also inclined at the angle θ1. In this way, with the center of the nozzle ejection surface <NUM> in the long side direction T as a reference, the nozzle head <NUM> is inclined at the same angle as the inclination angle θ1 of the portion opposed to the center, so that the distance between any side of one end side or the other end side of the painting width of the nozzle ejection surface <NUM> and the painting surface is prevented from becoming larger. This is also because the distance between the center of the nozzle ejection surface <NUM> in the long side direction T and the painting surface opposed to the center is often the smallest, and the portion opposed to the center of the long side direction T becomes the reference location P1.

However, it is also possible to set the posture data in the following manner to incline the nozzle head <NUM>, so that, for example, when the height difference <NUM> used as the reference location P1 is located close to one end side, the nozzle head <NUM> moves away from the other end side of the height difference and gradually approaches to the painting surface.

In addition, as shown in <FIG>, like the both end sides of the nozzle head <NUM> in the main scanning direction S, in the section (longitudinal cross section) along the main scanning direction S, the painting surface may be inclined relative to the horizontal plane sometimes. In this case, preferably, the posture data is formed so that when the portion opposed to the center of the nozzle ejection surface <NUM> in a short side direction (longitudinal width direction; in this case, it is consistent with the main scanning direction S) is inclined at an angle θ2, the short side direction S of the nozzle head <NUM> is also inclined at the angle θ2. However, it is not necessary to form the posture data in such a way that the short side direction S is inclined at the angle θ2. At this time, in order to ensure the uniformity of the film thickness, the concentration of the image data may be increased in accordance with the size of the angle θ2.

Here, in order to simplify the posture control of the nozzle head <NUM>, in the case where the nozzle head <NUM> is not inclined in the section along the main scanning direction S, the driving frequency H of the piezoelectric substrate <NUM> may also be changed to consistently maintain the painting film thickness. In this case, when the painting surface is horizontal, the driving frequency H of the piezoelectric substrate <NUM> is made to become <NUM>/cos θ times (in other words, greater than the frequency H). Thereby, the uniformity of the painting film thickness may be realized.

However, if the driving frequency H is made to become <NUM>/cos θ times as described above, and if facing to the large end portion side of the inclination angle θ2, the frequency of the painting head is increased. For example, if the inclination angle of the end portion is increased, for example, if the inclination angle is <NUM> degrees, the frequency H is made to become <NUM> times the frequency, and if the inclination angle is <NUM> degrees, the frequency H is doubled, and if the inclination angle is <NUM> degrees, the frequency H is made to become approximately three times the frequency. In this way, it is likely to reach an upper limit of the frequency. In order to cope with such a problem, for example, the arm control portion <NUM> may control the operation of the painting robot <NUM>, so that when reaching areas (end portion areas) on both end sides in the main scanning direction S, the moving speed (scanning speed) of the nozzle head <NUM> is slower than that before arrival.

In addition, as another method of suppressing the increase in the frequency as described, an average inclination angle of the inclination angles θ2 of the areas (end portion areas) on the both end sides in the main scanning direction S may be specified, and the end portion areas may be approximated to planes for painting.

In addition, when a portion with a large curvature such as the end portion area cannot be approximated to a plane, the length of the curve in the end portion area of the cross section along the main scanning direction S may also be calculated by integration, and if it is calculated to be several times (assuming R times) greater than a straight line parallel to the horizontal plane, driving control is performed on the piezoelectric substrate <NUM> at a frequency that is R times the driving frequency H. In this way, the uniformity of the painting film thickness is achieved. However, in order to simplify the calculation, the magnification relative to the driving frequency H is converted by simple approximation such as circular approximation instead of being calculated by integration as described above.

After the trajectory data D1 and the posture data are formed as described above, the image processing portion <NUM> forms divided painting data actually corresponding to the painting width L1 of the nozzle head <NUM> based on the above-mentioned painting three-dimensional model, the trajectory data D1 and the posture data (step S14). In this case, the painting three-dimensional model is divided based on the trajectory data D1, but the divided painting data is formed to include the overlapping portion L2 that overlaps with the adjacent divided painting data.

Next, after the divided painting data is formed, painting is performed relative to the vehicle (step S15).

The inkjet-type vehicle painting machine <NUM> having the above-mentioned structure is provided with: a robot arm (rotating shaft portion <NUM> to wrist portion <NUM>) capable of assembling a nozzle head <NUM> with a plurality of nozzles <NUM> to a front end portion and moving the assembled nozzle head <NUM>; an arm control portion <NUM> for controlling the operation of the robot arm; a head control portion <NUM> for controlling the driving of the nozzle head <NUM>; and painting data forming means (an image processing portion <NUM> and an arm control portion <NUM>) for forming, based on a painting range corresponding to a vehicle to be painted, painting data that is used for controlling the driving of the nozzle head <NUM> by means of the head control portion <NUM>.

Moreover, a plurality of nozzle columns <NUM> composed of nozzles <NUM> are arranged obliquely relative to a long side direction of the nozzle head <NUM>, the nozzle column <NUM> is provided with a first nozzle column 55A that is located on one side in a scanning direction of the nozzle head <NUM>, and a second nozzle column 55B that is located on the other side in the scanning direction, and the first nozzle column 55A and the second nozzle column 55B are configured in a state where the droplets ejected from the nozzles 55B in the second nozzle column 55B are ejected in the middle of the droplets ejected from adjacent nozzles <NUM> in the first nozzle column 55A when the long side direction of the nozzle head <NUM> is orthogonal to the scanning direction. Furthermore, the painting data forming means form trajectory data D1 for driving the robot arm to move the nozzle head <NUM>, and forms, based on the trajectory data D1, posture data for keeping the long side direction of the nozzle head <NUM> perpendicular relative to a main scanning direction of the nozzle head <NUM>. Furthermore, the arm control portion <NUM> controls the robot arm based on the trajectory data D1 and the posture data, so that the long side direction of the nozzle head <NUM> is kept perpendicular relative to the main scanning direction in a state where the nozzle head <NUM> moves along the main scanning direction and paint is ejected from the nozzle <NUM>.

In this way, when the nozzle head <NUM> moves along the main scanning direction based on the trajectory data D1 and performs painting, the long side direction of the nozzle head <NUM> is controlled by the arm control portion <NUM> based on the posture data to kept perpendicular relative to the main scanning direction. As a result, as shown in <FIG>, the nozzle head <NUM> can be prevented from tilting, and therefore, as shown in <FIG>, the formation of a portion where the droplets overlap with each other and a portion where the droplets do not overlap and leave gaps is prevented. Therefore, the uniformity of the painting film thickness for the vehicle may be ensured, and the painting quality may be improved.

In addition, in the present embodiment, preferably, the painting data forming means (the image processing portion <NUM> and the arm control portion <NUM>) take a location on a vehicle <NUM> side where the distance between the vehicle and a nozzle ejection surface <NUM> in the painting width of the nozzle head <NUM> is the closest as a reference location P1, and create the trajectory data D1 at higher than the reference location P1 by a position a predetermined height.

In the case of such a configuration, it is possible to prevent the nozzle head <NUM> (the nozzle ejection surface <NUM>) from interfering with a protruding location such as the height difference <NUM>. Therefore, it is possible to prevent the occurrence of poor painting due to a damage to the painting location by the nozzle head <NUM> (the nozzle ejection surface <NUM>).

In addition, in the present embodiment, preferably, the painting data forming means (the image processing portion <NUM> and the arm control portion <NUM>) form, before forming the trajectory data D1, a painting three-dimensional model for the painting range per painting range of the vehicle to be painted, and form divided painting data actually corresponding to the painting width of the nozzle head <NUM> based on the painting three-dimensional model, the trajectory data D1 and the posture data, and the divided painting data includes an overlapping portion L2 that overlaps with adjacent divided painting data.

In the case of such a configuration, since the divided painting data that is formed based on the painting three-dimensional model, the trajectory data D1 and the posture data includes the overlapping portion L2, it is possible to prevent the formation of a gap between the painting by scanning of a certain nozzle head <NUM> and the painting by scanning of a certain subsequent nozzle head <NUM>. In addition, by having the overlapping portion L2 as described above, within a range not lower than a lower limit of the overlapping portion L2, not only linear trajectory data D1, but also curved trajectory data D1 may be formed.

In addition, in the present embodiment, preferably, the painting data forming means (the image processing portion <NUM> and the arm control portion <NUM>) form the posture data, so that in a width direction of the vehicle, the nozzle head <NUM> is inclined at an inclination angle θ1 the same as the inclination angle θ1 of the painting location of the vehicle, which is located at a location opposed to the center of the nozzle head <NUM> in the long side direction.

In the case of such a configuration, as shown in <FIG>, in the width direction of the vehicle, the center of the nozzle head <NUM> can be in a state perpendicular to the painting location. Therefore, the both end sides of the nozzle head <NUM> in the long side direction are close to the painting location. Thereby, the paint may be made to fall on a desired position, and the painting quality may be improved. In addition, since the nozzle head <NUM> may be close to the painting location, it is possible to reduce the paint that scatters excessively, and thus the waste of the paint may be reduced.

In addition, in the present embodiment, preferably, the painting data forming means (the image processing portion <NUM> and the arm control portion <NUM>) form the posture data, so that in the long side direction of the vehicle, the nozzle head <NUM> is inclined at an inclination angle θ2 the same as the inclination angle θ2 of the painting location of the vehicle, which is located at a location opposed to the center of the nozzle head <NUM> in a short side direction.

In the case of such a configuration, as shown in <FIG>, in the long side direction of the vehicle, the center of the nozzle head <NUM> can be in a state perpendicular to the painting location. Therefore, the both end sides of the nozzle head <NUM> in the short side direction are close to the painting location. Thereby, the paint may be made to fall on a desired position, and the painting quality may be improved. In addition, since the nozzle head <NUM> may be close to the painting location, it is possible to reduce the paint that scatters excessively, and thus the waste of the paint may be reduced.

In addition, in the present embodiment, preferably, the painting data forming means (the image processing portion <NUM> and the arm control portion <NUM>) increase the concentration of the divided painting data according to the inclination angle of the location opposed to the center of the nozzle head <NUM> in the short side direction.

In the case of such a configuration, even for a location inclined relative to the horizontal plane, such as the end portion in the long side direction of the vehicle, the concentration of the divided painting data may be increased to form the same painting painting thickness as other locations. Thereby, the entire painting range of the vehicle may have a uniform painting film thickness.

One embodiment of the present invention has been described above, but the present invention may have various deformations in addition to the above-mentioned embodiment. Hereinafter, a deformation example will be described.

In the above-mentioned embodiment, before the divided painting data is formed, the trajectory data D1 is formed. However, it is also possible to form the divided painting data by means of the image processing portion <NUM> before the trajectory data D1 is formed.

That is, the painting data forming means (the image processing portion <NUM> and the arm control portion <NUM>) form, before forming the trajectory data D1, a painting three-dimensional model for the painting range per painting range of the vehicle to be painted. The painting data forming means form two-dimensional painting data for painting the vehicle based on the painting three-dimensional model. The painting data forming means form divided painting data actually corresponding to the painting width of the nozzle head based on the two-dimensional painting data. The painting data forming means form the trajectory data D1 based on the divided painting data.

In this case, as shown in <FIG>, first, a three-dimensional model (painting three-dimensional model) is formed in the image processing portion <NUM> (step S21). Next, based on the painting three-dimensional model, planar two-dimensional painting data is formed in the image processing portion <NUM> (step S22). Then, the two-dimensional painting data is divided by a painting width L1 that the nozzle head <NUM> may paint, so as to form divided painting data (step S23), wherein the painting width L1 further has the overlapping portion L2. After that, the arm control portion <NUM> forms trajectory data D1 for scanning by the nozzle head <NUM> above the divided painting data (step S24 ). Moreover, posture data is formed in a manner corresponding to the trajectory data D1 in the arm control portion <NUM> (step S25).

As described above, after the divided painting data, the trajectory data D1 and the posture data are formed, painting is performed relative to the vehicle (step S26). In this way, the painting may also be performed on the vehicle well.

Claim 1:
An inkjet-type vehicle painting machine (<NUM>) for performing painting by ejecting paint from nozzles (<NUM>) onto a vehicle (<NUM>) located on a painting line, the inkjet-type vehicle painting machine (<NUM>) comprising:
a nozzle head (<NUM>) having a plurality of the nozzles (<NUM>);
a robot arm (<NUM> to <NUM>) capable of assembling the nozzle head (<NUM>) to a front end portion and moving the assembled nozzle head (<NUM>);
an arm control portion (<NUM>) for controlling the operation of the robot arm (<NUM> to <NUM>);
a head control portion (<NUM>) for controlling a driving of the nozzle head (<NUM>); and
painting data forming means (<NUM> and <NUM>) for forming, based on a painting range corresponding to a vehicle (<NUM>) to be painted, painting data that is used for controlling a driving of the nozzle head (<NUM>) by means of the head control portion (<NUM>),
a plurality of nozzle columns (<NUM>) composed of the nozzles (<NUM>) being arranged obliquely relative to a long side direction (T) of the nozzle head (<NUM>),
the nozzle columns (<NUM>) being provided with a first nozzle column (55A) that is located on one side in a scanning direction (S) of the nozzle head (<NUM>) and a second nozzle column (55B) that is located on the other side in the scanning direction (S),
the first nozzle column (55A) and the second nozzle column (55B) being configured in a state where the droplets ejected from the nozzles (<NUM>) in the second nozzle column (55B) are ejected in the middle of the droplets ejected from adjacent nozzles (<NUM>) in the first nozzle column (55A) when the long side direction (T) of the nozzle head (<NUM>) is orthogonal to the scanning direction (S),
the painting data forming means (<NUM> and <NUM>):
forming trajectory data (D1) for driving the robot arm (<NUM> to <NUM>) to move the nozzle head (<NUM>), and
forming, based on the trajectory data (D1), posture data for keeping the long side direction (T) of the nozzle head (<NUM>) perpendicular relative to a main scanning direction (S) of the nozzle head (<NUM>), and
the arm control portion (<NUM>) controlling the robot arm (<NUM> to <NUM>) based on the trajectory data (D1) and the posture data, so that the long side direction (T) of the nozzle head (<NUM>) is kept perpendicular relative to the main scanning direction (S) in a state where the nozzle head (<NUM>) moves along the main scanning direction (S) and the paint is ejected from the nozzles (<NUM>).