Painting robot

Abstract

The present invention provides a painting robot capable of reducing the influence of pressure changes at the time of paint ejection or ejection stop. The painting robot includes a control section (100), a robot arm (R1) that mounts a painting head unit (50) to the front end, and a paint supply mechanism (70) that is provided across between the robot arm and the painting head unit, the paint supply mechanism including a paint circulation path (71) and a paint transfer mechanism (90, 91, control object) and a regulating valve (92, 93, control object) that are provided midway in the paint circulation path, the control section including a feedback control section (142) that calculates a pressure calculation value for performing feedback control of the action of the control object and controls the action of the control object, and a feedforward control section (143) that, based on a trigger signal associated with a change in the state of a painting head (53), corrects the pressure calculation value with a compensation pressure value in a direction opposite to a pressure change expected with respect to a pressure set value, and controls the action of the control object.

Description

TECHNICAL FIELD

[0001] The present application relates to a painting robot. BACKGROUND

[0002] In a painting line of a vehicle such as an automobile, a robot painting using a robot has become mainstream. As an example of a configuration related to this robot painting, for example, the following configuration is disclosed in Patent Literature 1. That is, in the painting robot disclosed in Patent Literature 1, a circulation device 200 is installed on the front end side of a robot arm 100. Inside the circulation device 200, a first proportional control valve 204 and a second proportional control valve 205 are provided, and a plurality of pressure sensors 208 to 211 are provided, and further a flowmeter 212 is provided. And, in the case where the posture of the circulation device 200 is changed, the opening degree of the first proportional control valve 204 and the second proportional control valve 205 is controlled by a control mode corresponding to a constant flow or a constant differential pressure, thereby adjusting the supply pressure and the recovery pressure, whereby control corresponding to the above control mode is realized.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: WO2021 / 040034 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in the configuration of the above Patent Literature 1, the measurement results of the pressure sensors and the flowmeter are transmitted to the processor. Therefore, at the time of, for example, paint ejection or ejection stop, a delay occurs in the responsiveness of the pump, the proportional control valve (paint regulator). Due to this delay in responsiveness, a pressure change occurs. If this pressure change occurs, in many cases, a situation where the pressure of the paint does not fall within the reference pressure range occurs.

[0008] The present application has been made in view of the above circumstances, and an object thereof is to provide a painting robot capable of reducing the influence of a pressure change at the time of paint ejection or ejection stop.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] To solve the above problems, a first aspect of the present application provides a painting robot that performs painting of a vehicle, including: a painting head unit that includes a painting head including a plurality of nozzles that eject droplets of paint; a robot arm that mounts the painting head unit to a front end and moves the painting head to a desired position; a paint supply mechanism that is disposed across between the robot arm and the painting head unit; and a control section that controls driving of the robot arm and the paint supply mechanism, the paint supply mechanism including: a paint circulation path that is disposed across between the robot arm and the painting head unit, supplies paint to the painting head, and recovers paint that is not ejected from the painting head; a paint transfer mechanism that is disposed midway through the paint circulation path and performs supply and recovery of paint between a paint storage site and the painting head; and a regulating valve that is disposed midway through the paint circulation path and can adjust opening and closing of an internal flow path of the paint circulation path, the control section including: a control memory that stores a pressure set value; a feedback control section that calculates a pressure calculation value for performing feedback control of the action of at least one of the paint transfer mechanism and the regulating valve to be the pressure set value read from the control memory; and a feedforward control section that, based on a trigger signal associated with a change in state of the painting head, corrects the pressure calculation value by a compensation pressure value in a direction opposite to an expected change in pressure with respect to the pressure set value, and controls the action of at least one of the paint transfer mechanism and the regulating valve.

[0011] In the above invention, preferably, the paint circulation path includes: a paint supply passage that supplies paint to the painting head; and a return flow path that is connected to a paint discharge side of the painting head and recovers paint that is not ejected from the nozzles, the paint transfer mechanism includes: a paint supply unit that is mounted to a prescribed position of the robot arm, disposed midway through the paint supply passage, and applies a pressure for supplying paint to the painting head based on control by the control section; and a paint recovery mechanism that is mounted to a prescribed position of the robot arm, disposed midway through the return flow path, and applies a pressure for recovering paint that is not ejected from the painting head on a downstream side of the return flow path based on control by the control section, and the feedforward control section corrects the pressure calculation value by a compensation pressure value that corrects the paint supply unit to an increase side of driving based on a trigger signal associated with start of ejection, and causes the paint supply unit to act, wherein the start of ejection is start of ejection that changes from a state in which the painting head stops ejection of paint.

[0012] In the above invention, preferably, the feedforward control section corrects the pressure calculation value by a compensation pressure value that corrects the paint recovery mechanism to a decrease side of driving based on a trigger signal associated with start of ejection, and causes the paint recovery mechanism to act, wherein the start of ejection is start of ejection that changes from a state in which the painting head stops ejection of paint.

[0013] Further, in the above invention, it is preferable that the feedforward control section corrects the pressure operation value by a compensation pressure value that corrects the paint supply unit to the drive stop side based on a trigger signal associated with the discharge stop that is a change from a state in which the paint is discharged from the painting head, and causes the paint supply unit to operate.

[0014] Further, in the above invention, it is preferable that the feedforward control section corrects the pressure operation value by a compensation pressure value that corrects the paint supply unit to the drive stop side based on a trigger signal associated with the discharge stop that is a change from a state in which the paint is discharged from the painting head, and causes the paint supply unit to operate.

[0015] Further, in the above invention, it is preferable that the feedforward control section corrects the pressure operation value by a compensation pressure value that corrects the paint supply unit to the drive stop side based on a trigger signal associated with the discharge stop that is a change from a state in which the paint is discharged from the painting head, and causes the paint supply unit to operate.

[0016] Further, in the above invention, it is preferable that the feedforward control section corrects the pressure operation value by a compensation pressure value that corrects the paint supply unit to the drive stop side based on a trigger signal associated with the discharge stop that is a change from a state in which the paint is discharged from the painting head, and causes the paint supply unit to operate.

[0017] Further, in the above invention, it is preferable that the feedforward control section corrects the pressure operation value by a compensation pressure value that corrects the paint supply unit to the drive stop side based on a trigger signal associated with the discharge stop that is a change from a state in which the paint is discharged from the painting head, and causes the paint supply unit to operate.

[0018] Further, in the above invention, it is preferable that the feedforward control section corrects the pressure operation value by a compensation pressure value that corrects the paint supply unit to the drive stop side based on a trigger signal associated with the discharge stop that is a change from a state in which the paint is discharged from the painting head, and causes the paint supply unit to operate.

[0019] Further, in the above invention, it is preferable that the feedforward control section corrects the pressure calculation value by a compensation pressure value that corrects the second regulating valve to the opening side, based on a trigger signal associated with a change in the state of paint ejection from the coating head, and controls the operation of at least one of the paint transfer mechanism and the regulating valve.

[0020] Further, in the above invention, it is preferable that the feedforward control section corrects the pressure calculation value by a compensation pressure value that corrects the second regulating valve to the opening side, based on a trigger signal associated with a change in the state of paint ejection from the coating head, and controls the operation of at least one of the paint transfer mechanism and the regulating valve.

[0021] Effects of Invention

[0022] According to the present invention, it is possible to provide a coating robot that can reduce the influence of a change in pressure at the time of paint ejection or ejection stop. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a diagram showing the overall configuration of a coating robot according to one embodiment of the present invention.

[0024] Figure 2 is a diagram showing the state of a nozzle forming surface in the coating robot shown in Figure 1

[0025] Figure 3 is a diagram showing the state of a plurality of coating heads being arranged in a staggered manner in the coating robot shown in Figure 1

[0026] Figure 4 Figure 1

[0027] Figure 5 Figure 4

[0028] Figure 6 Figure 2

[0029] Figure 7 Figure 1

[0030] Figure 8 Figure 1 ​​​​​​​​​​​Fig. 1 is a diagram showing an outline configuration of a control section of a painting robot.

[0031] Figure 9 Fig. 2 is a diagram showing an outline configuration of a painting robot. Figure 1 Fig. 3 is a diagram showing an outline configuration of a paint supply control section of a painting robot.

[0032] Figure 10 Fig. 4 is a diagram showing an example of a result of verification of a pressure change when a control object is not subjected to feedforward control but is controlled only with feedback control to eject paint from a painting head in the painting robot shown in Fig. 2. Figure 1

[0033] Fig. 5 is a diagram showing an example of a result of verification of a pressure change when a control object is subjected to feedforward control and feedback control to eject paint from a painting head in the painting robot shown in Fig. 2. Figure 11 Figure 1 Fig. 6 is a diagram showing an example of a result of verification of a pressure change when a control object is subjected to feedforward control and feedback control to eject paint from a painting head in the painting robot shown in Fig. 2.

[0034] Figure 12 Figure 1 Fig. 7 is a diagram showing a picture of a case where a painting head reaches a prescribed position on a movement path in the painting robot shown in Fig. 2.

[0035] Figure 13 Fig. 8 is a diagram showing a picture of a state where a painting head is inclined with respect to a direction orthogonal to a direction of a painting path in the painting robot shown in Fig. 2. Figure 1

[0036] Fig. 9 is a diagram showing an outline configuration of a painting robot.

[0037] Fig. 10 is a diagram showing an outline configuration of a painting robot.​​10... painting robot, 11... painting robot system, 20... robot main body, 21... base, 22a... 1st rotation axis, 22b... 2nd rotation axis, 22c... 3rd rotation axis, 22d... 4th rotation axis, 22e... 5th rotation axis, 22f... 6th rotation axis, 24... 1st turning arm, 25... 2nd turning arm, 26... turning arm, 27... wrist, 50... painting head unit, 52... nozzle forming surface, 53... painting head, 54... nozzle, 55... nozzle row, 55A... 1st nozzle row, 55B... 2nd nozzle row, 57... supply-side large flow path, 58... row-direction supply flow path, 59... nozzle pressurization chamber, 59a... nozzle supply flow path, 59b... nozzle discharge flow path, 60... row-direction discharge flow path, 61... discharge-side large flow path, 62... piezoelectric substrate, 63a... piezoelectric ceramic layer, 63b... piezoelectric ceramic layer, 64... common electrode, 65... independent electrode, 70... paint supply mechanism, 71... paint circulation path, 72... paint supply passage, 73... return flow path, 74... bypass flow path, 75... external supply passage, 76... bubble removal member, 77... three-way valve, 78... on-off valve, 79... three-way valve, 80... switching valve, 81... discharge path, 90... supply pump (corresponding to paint supply unit), 91... suction pump (corresponding to paint recovery mechanism), 92... 1st paint regulator (corresponding to 1st regulating valve), 93... 2nd paint regulator (corresponding to 2nd regulating valve), 94... degassing assembly, 95... removal filter, 96... suction line, 97... vacuum pump, 100... control section, 110... main control section, 120... arm control section, 130... head control section, 140... paint supply control section, 141, 144... adder, 142... feedback control section, 143... feedforward control section, 150... control memory, 200... image processing device, 210... image processing section, 220... memory, 300... position sensor, 310... tilt sensor (corresponding to angle detection mechanism), FM1... 1st flowmeter, FM2... 2nd flowmeter, FR... vehicle, PS... painting path, R1... robot arm, S1-S8... pressure sensor DETAILED DESCRIPTION

[0038] Hereinafter, a painting robot 10 according to each embodiment of the present application will be described based on the drawings. Note that in the following description, the X direction is set as the length direction of the nozzle forming surface 52 (painting head 53) as needed, the X1 side is the right side in FIG. 1, and the X2 side is the left side in FIG. 1. Also, the Y direction is set as the short side direction (width direction) of the nozzle forming surface 52 (painting head 53) as needed, the Y1 side is the paper upper side in FIG. 1, and the Y2 side is the paper lower side in FIG. 1. Figure 2 Figure 2 Figure 2 Figure 2

[0039] ​​​​The painting robot 10 of the present embodiment aims to perform "painting" on a painting target object such as a vehicle or a vehicle component (hereinafter, a vehicle component as a part of a vehicle is also explained as a vehicle) on a painting line in a vehicle manufacturing plant, and to form a paint film on the surface of the painting target object to impart surface protection and beauty thereto. Therefore, it is necessary to perform painting on a vehicle moving along the painting line at a desired painting quality for a certain period of time every prescribed time.

[0040] In addition, in the painting robot 10 of the present embodiment, not only the above-described paint film but also various designs and images can be formed on a painting target object such as a vehicle or a vehicle component. Note that the painting target object is not limited to a vehicle or a vehicle component, and is a structure that needs to be painted such as various components other than vehicles (as an example, an outer member of an airplane or a railway) and the like.

[0041] (1-1. Overall configuration of painting robot for vehicle)

[0042] Figure 1 is a schematic view showing the overall configuration of the painting robot 10 of the first embodiment of the present application. As shown in Figure 1 , the painting robot 10 includes a robot main body 20 and a painting head unit 50 as main constituent elements. As an example thereof, Figure 1 The painting robot 10 shown in

[0043] (1-2. Painting device main body)

[0044] As shown in Figure 1 , the robot main body 20 includes a base 21, first to sixth rotating shafts 22a to 22f, a leg portion 23, a first turning arm 24, a second turning arm 25, a rotating arm 26, a wrist portion 27, and not-illustrated motors for driving these portions as main constituent elements. Note that the portion from the leg portion 23 to the wrist portion 27 corresponds to a robot arm R1, but a portion other than the base 21 and the like can also correspond to the robot arm R1.

[0045] The base 21 is a portion provided at a setting site such as a floor, and can be able to travel with respect to the setting site. In addition, the leg portion 23 is a portion erected upward from the base 21, and is provided so as to be able to rotate with respect to the base 21 by driving of a not-illustrated motor (first motor) via the first rotating shaft 22a. Note that the leg portion 23 can also be configured not to rotate with respect to the base 21.

[0046] Further, a first rotary arm 24 is provided at the upper end of the leg 23, and the first rotary arm 24 is rotatable by the driving of an electric motor (second electric motor) not shown via the second rotary shaft 22. Further, a second rotary arm 25 is provided at the front end side of the first rotary arm 24, and the second rotary arm 25 is rotatable by the driving of an electric motor (third electric motor) not shown via the third rotary shaft 22c.

[0047] Further, a rotary arm 26 is provided at the front end side of the second rotary arm 25, and the rotary arm 26 is rotatable about the center axis of the second rotary arm 25. The rotary arm 26 is rotatable by the driving of an electric motor (fourth electric motor) not shown via the fourth rotary shaft 22d. Further, a wrist 27 is provided at the front end side of the rotary arm 26. The wrist 27 is rotatable about a plurality of (for example, two) different axes. In Figure 1 the present embodiment, the rotary shafts about which the rotary motion is possible are provided as a fifth rotary shaft 22e and a sixth rotary shaft 22f, respectively. Thus, the orientation of the coating head unit 50 can be controlled with high precision. Note that the number of axes is two or more, and can be any number.

[0048] Further, the coating head unit 50 is attached to the wrist 27, but the coating head unit 50 can be provided detachably with respect to the wrist 27.

[0049] (1-3. Regarding the coating head unit)

[0050] Next, the coating head unit 50 will be described. Figure 2 is a view showing the state of a nozzle formation surface 52 in which the nozzles that eject paint in the coating head unit 50 are observed from the front. As Figure 2 shown, the coating head unit 50 has a head cover portion not shown, in which a plurality of components are built in. As Figure 2 shown, a plurality of nozzles 54 are formed on the nozzle formation surface 52 in a nozzle row 55 in which the nozzles 54 are connected in a direction inclined with respect to the length direction of the coating head unit 50. In the present embodiment, the nozzle row 55 is provided with a first nozzle row 55A on one side (Y2 side) in the main scanning direction (Y direction) and a second nozzle row 55B on the other side (Yl side) in the main scanning direction.

[0051] Note that, in the case of ejecting paint, the driving timing of each nozzle 54 is controlled so that the droplets ejected from the nozzles 54 in the second nozzle row 55B land between the droplets ejected from the adjacent nozzles 54 in the first nozzle row 55A. Thus, the dot density at the time of coating can be increased.

[0052] However, as Figure 2As shown, a single coating head 53 is present on the nozzle formation surface 52. However, a head group composed of a plurality of coating heads 53 can also be present on the nozzle formation surface 52. In this case, as an example, as shown in FIG. 2, a configuration in which the plurality of coating heads 53 are aligned and arranged in a staggered manner can be given, but the arrangement of the coating heads 53 in the head group can not be in a staggered manner. Figure 3

[0053] Figure 4 is a diagram showing the outline configuration of the supply of paint to each nozzle 54. Figure 5 is a cross-sectional view showing the configuration in the vicinity of the column direction supply flow path 58, the nozzle pressurization chamber 59, and the column direction discharge flow path 60. As shown in FIG. 3, the column direction supply flow path 58, the nozzle pressurization chamber 59, and the column direction discharge flow path 60 are formed in the nozzle formation surface 52. Figure 4 Figure 5 As shown, the coating head 53 is provided with a supply side large flow path 57, a column direction supply flow path 58, a nozzle pressurization chamber 59, a column direction discharge flow path 60, and a discharge side large flow path 61. The supply side large flow path 57 is a flow path that supplies paint from a paint supply passage 72 of a paint supply mechanism 70 described later. In addition, the column direction supply flow path 58 is a flow path that branches the paint in the supply side large flow path 57.

[0054] In addition, the nozzle pressurization chamber 59 is connected to the column direction supply flow path 58 via a nozzle supply flow path 59a. Thereby, paint is supplied from the column direction supply flow path 58 to the nozzle pressurization chamber 59. This nozzle pressurization chamber 59 is provided corresponding to the number of nozzles 54, and can eject the paint inside from the nozzles 54 using a piezoelectric substrate 62 described later.

[0055] In addition, the nozzle pressurization chamber 59 is connected to the column direction discharge flow path 60 via a nozzle discharge flow path 59b. Therefore, paint that is not ejected from the nozzles 54 is discharged from the inside of the nozzle pressurization chamber 59 to the column direction discharge flow path 60 via the nozzle discharge flow path 59b. In addition, the column direction discharge flow path 60 is connected to the discharge side large flow path 61. The discharge side large flow path 61 is a flow path in which the paint discharged from each column direction discharge flow path 60 is merged. This discharge side large flow path 61 is connected to a return flow path 73 of the paint supply mechanism 70 described later.

[0056] By such a configuration, the paint supplied from the paint supply passage 72 of the paint supply mechanism 70 described later is ejected from the nozzles 54 via the supply side large flow path 57, the column direction supply flow path 58, the nozzle supply flow path 59a, and the nozzle pressurization chamber 59. In addition, the paint that is not ejected from the nozzles 54 is returned to the return flow path 73 of the paint supply mechanism 70 described later via the nozzle pressurization chamber 59, the nozzle discharge flow path 59b, the column direction discharge flow path 60, and the discharge side large flow path 61.

[0057] Note that, in the above-described embodiment, the coating head 53 is provided with the supply side large flow path 57, the column direction supply flow path 58, the nozzle pressurization chamber 59, the column direction discharge flow path 60, and the discharge side large flow path 61. However, the coating head 53 can be provided with only the nozzle pressurization chamber 59, and the supply side large flow path 57, the column direction supply flow path 58, the column direction discharge flow path 60, and the discharge side large flow path 61 can be formed in the nozzle formation surface 52. Figure 4 ​​In the configuration shown, one column-direction discharge flow path 60 is provided corresponding to one column-direction supply flow path 58. However, multiple (e.g., two) column-direction discharge flow paths 60 may also be provided corresponding to one column-direction supply flow path 58. Alternatively, one column-direction discharge flow path 60 may be provided corresponding to multiple column-direction supply flow paths 58.

[0058] In addition, such as Figure 5 As shown, a piezoelectric substrate 62 is disposed on the top surface of the nozzle pressurization chamber 59 (the surface opposite to the nozzle 54). This piezoelectric substrate 62 has two piezoelectric ceramic layers 63a and 63b serving as piezoelectric elements, and further includes a common electrode 64 and an independent electrode 65. The piezoelectric ceramic layers 63a and 63b are components that can expand and contract when an external voltage is applied. Ferroelectric lead zirconate titanate (PZT), NaNbO3, BaTiO3, (BiNa)NbO3, and BiNaNb5O series piezoelectric ceramic layers 63a and 63b can be used as such piezoelectric ceramic layers. 15 Ceramic materials such as ceramics.

[0059] In addition, such as Figure 5 As shown, a common electrode 64 is disposed between piezoelectric ceramic layers 63a and 63b. Additionally, a surface electrode (not shown) for the common electrode is formed on the upper surface of the piezoelectric substrate 62. These common electrodes 64 and the surface electrode are electrically connected via a through conductor (not shown) in the piezoelectric ceramic layer 63a. Furthermore, individual electrodes 65 are disposed at locations opposite to the nozzle pressure chamber 59. Moreover, the portion of the piezoelectric ceramic layer 63a sandwiched between the common electrode 64 and the individual electrodes 65 is polarized in the thickness direction. Therefore, when a voltage is applied to the individual electrodes 65, the piezoelectric ceramic layer 63a deforms due to the piezoelectric effect. Consequently, when a predetermined driving signal is applied to the individual electrodes 65, the piezoelectric ceramic layer 63b changes relative to the individual electrodes, reducing the volume of the nozzle pressure chamber 59, thereby extruding the coating.

[0060] It should be noted that, in Figure 5 In this process, the common electrode 64 is disposed on the top surface of the nozzle pressurization chamber 59, but the common electrode 64 is not limited to... Figure 5 The configuration shown is arranged on the top surface of the nozzle pressurization chamber 59. For example, the common electrode 64 can also be arranged on the side surface of the nozzle pressurization chamber 59 (a surface orthogonal or substantially orthogonal to the top surface mentioned above). In addition, any configuration can be used as long as the paint can be sprayed out of the nozzle 54 well.

[0061] (1-4. Other components of the painting head unit)

[0062] Next, the other components of the painting head unit 50 will be explained. Figure 6is a plan view showing the configuration of the nozzle formation surface 52 of another coating head unit 50. As shown in Figure 6 It is also possible to arrange a plurality of nozzles 54 in the short side direction (width direction; Y direction) of the coating head 53 to configure a nozzle row 55. Note that in the configuration shown in Figure 6 In the configuration shown in

[0063] In addition, in the case where the coating head 53 shown in Figure 6 is used to coat a vehicle, it is also possible to perform coating in a state where the length direction of the coating head 53 is slightly inclined with respect to the main scanning direction of the coating head 53. For example, in the configuration of the coating head 53 shown in Figure 2 If the nozzle row 55 is inclined by an angle a with respect to the main scanning direction, it is sufficient to incline the length direction of the coating head 53 by the angle a with respect to the main scanning direction of the coating head 53. In such an inclined state, it is possible to apply the same coating as the coating head 53 shown in Figure 2 by adjusting only the ejection timing of the paint from each nozzle 54.

[0064] (1-5. Regarding the paint supply mechanism)

[0065] Next, the paint supply mechanism 70 and the bubble removing member and the flowmeter provided in the paint supply mechanism 70 will be described.

[0066] Figure 7 is a diagram showing the schematic configuration of the paint supply mechanism 70 and the like. The paint supply mechanism 70 has, as main constituent elements, a paint circulation path 71, an external supply passage 75, a bubble removing member 76, a supply pump 90, a suction pump 91, a first paint regulator 92, a second paint regulator 93, a degassing assembly 94, a removal filter 95, pressure sensors S1 to S8, a first flowmeter FM1, and a second flowmeter FM2.

[0067] The paint circulation path 71 is a flow path for circulating paint, and has a paint supply passage 72, a return flow path 73, and a bypass flow path 74. The paint supply passage 72 is a flow path for supplying paint supplied from the external supply passage 75 or returned from the return flow path 73 toward the coating head 53, and is connected to the above-mentioned supply-side large flow path 57.

[0068] The return flow path 73 is connected to the discharge-side large flow path 61 of the coating head 53, and is a flow path for returning paint that is not ejected from the coating head 53 to the bubble removing member 76.

[0069] The bypass flow path 74 is a flow path that connects the paint supply path 72 and the return flow path 73. That is, the bypass flow path 74 is provided in a state of being parallel to the painting head 53, and in a case where paint is not ejected from the painting head 53, paint flows into the bypass flow path 74 by switching the operation of a three-way valve 77 described later.

[0070] The external supply path 75 is a pipe for supplying paint supplied from the paint storage part side such as a circulation container to the inside of the container main body of the bubble removing member 76.

[0071] The bubble removing member 76 is a member for removing bubbles contained in paint. The bubble removing member 76 is provided at a stable part outside the robot arm Rl in a posture that does not change. In addition, the bubble removing member 76 is connected to the paint supply path 72 in a manner that paint can be supplied, and is connected to the return flow path 73 in a manner that paint is supplied from the return flow path 73. The bubble removing member 76 has a container main body that can be sealed from the outside, and an exhaust port for exhausting gas generated by bubbles accumulated inside is provided on the container main body.

[0072] In addition, the paint supply path 72 is connected to the three-way valve 77 at a downstream side compared to a first paint regulator 92 described later. The three-way valve 77 is connected to a middle part of the paint supply path 72, and is also connected to the bypass flow path 74. Therefore, at the time of painting, the upstream side and the downstream side of the paint supply path 72 compared to the three-way valve 77 are in an open state, and paint is supplied to the painting head 53. On the other hand, in a case where painting is not performed, it is switched so that paint flowing in the paint supply path 72 flows to the bypass flow path 74, and paint is not supplied to the downstream side of the paint supply path 72 (the painting head 53 side).

[0073] In addition, an on-off valve 78 is provided at a middle part of the bypass flow path 74 described above. By operating the on-off valve 78 to open, paint can flow in the bypass flow path 74.

[0074] Further, a three-way valve 79 is connected to the downstream side of the bypass flow path 74 compared to the on-off valve 78, and the three-way valve 79 is connected to the upstream side of the return flow path 73 (that is, the painting head 53 side of the return flow path 73) and the downstream side of the return flow path 73 (that is, the suction pump 91 side described later of the return flow path 73). Therefore, in a case where painting is performed, the upstream side and the downstream side of the return flow path 73 compared to the three-way valve 79 become an open state, and paint that is not ejected from the painting head 53 flows to the downstream side of the return flow path 73. On the other hand, in a case where painting is not performed, the three-way valve 79 is switched so that paint flowing in the bypass flow path 74 flows to the downstream side of the return flow path 73 (the suction pump 91 side).

[0075] Additionally, a switching valve 80 is disposed downstream of the supply pump 90 described later in the return flow path 73. This switching valve 80 is also a three-way valve, connecting not only the upstream and downstream sides of the return flow path 73 but also the discharge path 81. Under normal conditions, the switching valve 80 allows paint to flow on both the upstream and downstream sides of the return flow path 73. However, when, for example, cleaning liquid flows from the paint supply passage 72 through the coating head 53 or the bypass flow path 74 to the return flow path 73, the switching valve 80 switches, and the cleaning liquid (waste liquid) is discharged through the discharge path 81.

[0076] It should be noted that the return flow path 73 is connected to the aforementioned bubble removal component 76 on the downstream side compared to the switching valve 80.

[0077] Additionally, a supply pump 90 is connected midway through the paint supply passage 72. It should be noted that the supply pump 90 corresponds to the paint transfer mechanism and the paint supply unit. The supply pump 90 is a mechanism that applies positive pressure to the paint flowing in the paint supply passage 72 towards the downstream side. It should be noted that, as the supply pump 90, a gear pump capable of controlling the amount of paint supplied by controlling the rotational speed is preferably used. However, pumps other than gear pumps can also be used. The operation of the supply pump 90 is controlled by the control unit 100, described later. Thus, the operation of the supply pump 90 can be controlled to a predetermined pressure setpoint.

[0078] Additionally, a suction pump 91 is connected midway through the return flow path 73. It should be noted that the suction pump 91 corresponds to both the paint transfer mechanism and the paint recovery mechanism. The suction pump 91 is a mechanism that applies negative pressure to the paint flowing in the return flow path 73 upstream of the supply pump 90. It should be noted that, similar to the supply pump 90, a gear pump, capable of controlling the paint supply amount by controlling the rotational speed, is preferably used as the suction pump 91. However, pumps other than gear pumps can also be used for the suction pump 91. The operation of the suction pump 91 is also controlled by the control unit 100, described later. Thus, the operation of the suction pump 91 can be controlled to maintain a predetermined pressure setpoint downstream of it.

[0079] Furthermore, in the paint supply passage 72, a first paint regulator 92 is disposed downstream of the supply pump 90. The first paint regulator 92 mitigates the pulsations in the supply pump 90 and supplies paint at a constant pressure. It should be noted that the first paint regulator 92 corresponds to a regulating valve and a first regulating valve. The opening degree of this first paint regulator 92 can be adjusted by the control unit 100 described later, corresponding to control air pressure and electrical signals. Thus, the pressure downstream of the first paint regulator 92 can be controlled to a predetermined pressure setpoint, corresponding to the pressure upstream of the first paint regulator 92.

[0080] Further, in the return flow path 73, a second paint regulator 93 is arranged on the upstream side compared to the suction pump 91. The second paint regulator 93 moderates the pulsation in the suction pump 91 and sucks the paint at a constant pressure (negative pressure). Note that the second paint regulator 93 corresponds to the regulating valve and the second regulating valve. The second paint regulator 93 can also adjust the opening degree in response to the control air pressure, the electric signal by the control of the control section 100 described later. Thus, the pressure on the upstream side of the second paint regulator 93 can be controlled to a prescribed pressure set value in response to the pressure on the downstream side of the second paint regulator 93.

[0081] Further, in the paint supply path 72, a degassing assembly 94 is arranged on the downstream side compared to the supply pump 90 and on the upstream side compared to the first paint regulator 92. The degassing assembly 94 is arranged on the downstream side of the paint supply path 72 compared to the removal filter 95 described later and functions to remove the dissolved gas dissolved in the paint (degassing).

[0082] Further, in the paint supply path 72, a removal filter 95 is arranged on the upstream side compared to the degassing assembly 94 and on the downstream side compared to the supply pump 90. The removal filter 95 removes foreign matter contained in the paint flowing in the paint supply path 72. The removal filter 95 reliably removes coarse foreign matter, pigment aggregates from the paint containing the pigment, for example, and thereby maintains the painting head 53 in normal operation.

[0083] Next, the pressure sensors S1 to S8 and the flow meters FM1, FM2 will be described. In the paint supply path 72, a pressure sensor S1 is arranged on the upstream side of the supply pump 90. Also, in the paint supply path 72, a pressure sensor S2 is arranged on the downstream side compared to the supply pump 90 and on the upstream side compared to the removal filter 95. The pressure sensor S1 measures the supply pressure of the paint to the supply pump 90 and transmits the measurement result to the control section 100. Further, the pressure sensor S2 measures the pressure of the paint ejected from the supply pump 90 and transmits the measurement result to the control section 100.

[0084] As such, by measuring the pressure of the paint on the upstream side and the downstream side of the supply pump 90 with the pressure sensors S1, S2, the estimated pressure of the supply pump 90 can be measured with high accuracy. Note that the estimated pressure of the supply pump 90 can be set to the average of the pressure value of the pressure sensor S1 and the pressure value of the pressure sensor S2 or the pressure value of one of them. Further, the above estimated pressure is used to calculate the head pressure and the head pressure difference described later.

[0085] Further, the above-described degassing assembly 94 is connected to a vacuum pump 97 via a suction line 96. As described above, the vacuum pump 97 is used to depressurize the inside of the frame of the degassing assembly 94 (the inside of the hollow fiber membrane). By this depressurization, dissolved gas dissolved in the paint supplied to the inside of the frame is removed (degassed).

[0086] Further, a pressure sensor S3 measures the pressure of the suction line 96 between the above-described vacuum pump 97 and the degassing assembly 94.

[0087] Note that, in the paint supply passage 72, a first flowmeter FM1 is disposed on the downstream side compared to the degassing assembly 94 and on the upstream side compared to the first paint regulator 92. The first flowmeter FM1 measures the flow rate of the paint sent to the first paint regulator 92 and sends the result of the measurement to the control section 100. This first flowmeter FM1 is a non-contact type flowmeter such as an ultrasonic wave type, optical type, electromagnetic type, thermal type, etc. that does not have a movable portion, and therefore the first flowmeter FM1 is disposed outside the paint supply passage 72. Note that, the first flowmeter FM1 can also use a flowmeter that has a movable portion.

[0088] Here, in the case where the first flowmeter FM1 is of the optical type, at least the portion of the paint supply passage 72 in which the flow rate is measured by the first flowmeter FM1 is made transparent. However, in the case where the first flowmeter FM1 is of the ultrasonic wave type other than the optical type, at least the portion of the paint supply passage 72 in which the flow rate is measured by the first flowmeter FM1 does not need to be made transparent.

[0089] Further, in the paint supply passage 72, a pressure sensor S4 is disposed on the downstream side compared to the first flowmeter FM1 and on the upstream side compared to the first paint regulator 92. Further, in the paint supply passage 72, a pressure sensor S5 is disposed on the downstream side compared to the first paint regulator 92 and on the upstream side compared to the three-way valve 77. The pressure sensor S4 measures the supply pressure of the paint to the first paint regulator 92 and sends the result of the measurement to the control section 100. Further, the pressure sensor S5 measures the pressure of the paint ejected from the first paint regulator 92 and sends the result of the measurement to the control section 100.

[0090] As such, by measuring the pressure of the paint on the upstream side and the downstream side of the first paint regulator 92 using the pressure sensors S4, S5, it is possible to measure the estimated pressure of the first paint regulator 92 with high accuracy. Note that, the estimated pressure of the first paint regulator 92 can be set to the average of the pressure value of the pressure sensor S4 and the pressure value of the pressure sensor S5, or the pressure value of one of them.

[0091] Note that, preferably, the pressure sensor S4 is provided in the paint supply mechanism 70, but a configuration in which the pressure sensor S4 is omitted can also be adopted. Also, the pressure sensor S4 can be provided on the painting head unit 50 side or on the 2nd rotating arm 25 side (the robot arm Rl side). Also, the pressure sensor S4 can be provided on the upstream side from the 1st flowmeter FMl.

[0092] Also, in the return flow path 73, a pressure sensor S6 is provided on the downstream side of the three-way valve 79 and on the upstream side of the 2nd paint regulator 93. Also, in the return flow path 73, a pressure sensor S7 is provided on the downstream side of the 2nd paint regulator 93 from a flowmeter FM2 (described later) on the further downstream side. The pressure sensor S6 measures the supply pressure of the paint to the 2nd paint regulator 93 and transmits the measurement result to the control section 100. Also, the pressure sensor S7 measures the pressure of the paint ejected from the 2nd paint regulator 93 (i.e., the supply pressure of the paint to the suction pump 91) and transmits the measurement result to the control section 100.

[0093] In this way, by measuring the pressure of the paint on the upstream side and the downstream side of the 2nd paint regulator 93 with the pressure sensors S6, S7, it is possible to measure the estimated pressure of the 2nd paint regulator 93 with high accuracy. Note that, the estimated pressure of the 2nd paint regulator 93 can be set to the average of the pressure value of the pressure sensor S6 and the pressure value of the pressure sensor S7, or to the pressure value of one of them.

[0094] Note that, in the return flow path 73, a pressure sensor can also be provided on the downstream side of the 2nd paint regulator 93 and on the upstream side of the flowmeter FM2.

[0095] Also, in the return flow path 73, a 2nd flowmeter FM2 is provided on the downstream side of the 2nd paint regulator 93. The 2nd flowmeter FM2 measures the flow rate of the paint sent to the suction pump 91 and transmits the measurement result to the control section 100. This 2nd flowmeter FM2, like the 1st flowmeter FMl described above, is also a non-contact type flowmeter such as an ultrasonic wave type, an optical type, an electromagnetic type, a thermal type, etc. that has no movable part, so a detailed description thereof is omitted. Note that, the 2nd flowmeter FM2 can also use a flowmeter that has a movable part.

[0096] Also, in the return flow path 73, a pressure sensor S8 is provided on the downstream side of the suction pump 91 and on the upstream side of the above-mentioned switching valve 80. The pressure sensor S8 measures the pressure of the paint ejected from the suction pump 91 and transmits the measurement result to the control section 100.

[0097] As such, by measuring the pressure of the paint on the upstream side and the downstream side of the suction pump 91 using the pressure sensors S7, S8, it is possible to measure the estimated pressure of the suction pump 91 with high precision. Note that the estimated pressure of the suction pump 91 can be set to the average of the pressure value of the pressure sensor S7 and the pressure value of the pressure sensor S8, or the pressure value of one of them.

[0098] (1-8. Outline Configuration of Control Section)

[0099] Next, the outline configuration of the control section 100 for controlling the operation of the painting robot 10 will be described. Figure 8 is a view showing the outline configuration of the control centered on the control section 100 of the painting robot 10. As shown in Figure 8 , the control section 100 has a main control section 110, an arm control section 120, a head control section 130, a paint supply control section 140, a control memory 150, a position sensor 300, and a tilt sensor 310 as main constituent elements. In addition, the painting robot 10 constitutes a painting robot system (reference numerals are omitted) by being connected to the image processing device 200.

[0100] Note that the main control section 110, the arm control section 120, the head control section 130, the paint supply control section 140, and the image processing section 210 described later are constituted by elements such as a CPU (Central Processing Unit), a storage site (ROM (Read Only Memory), RAM (Random Access Memory), a nonvolatile memory, and the like), and the like. Note that the image processing section 210 can also be used together with or instead of the CPU using a GPU (Graphics Processing Unit) having excellent image processing performance.

[0101] The main control section 110 in the above-described control configuration transmits a prescribed control signal to the above-described arm control section 120, the head control section 130, and the paint supply control section 140, so that each motor (1st to 6th motors) of the robot arm R1, each moving part of the paint supply mechanism 70, and the piezoelectric substrate 62 are caused to act in cooperation to perform painting on the painting target object.

[0102] In addition, the arm control section 120 is a section that controls the driving of each motor (1st to 6th motors) of the above-described robot arm Rl. This arm control section 120 is provided with an arm-use memory (omitted from the drawing) in which data (trajectory data) related to the trajectory of the painting head 53 and attitude data related to the attitude such as the inclination of the painting head 53 are stored, and these data are created by robot teaching that takes into account the paintable width in the painting head 53.

[0103] Also, in the arm control section 120, the driving of each motor (1st to 6th motors) of the above-described robot arm Rl is controlled on the basis of the trajectory data and the attitude data stored in the arm-use memory and the image processing of the image processing section 210 described later. By this control, the painting head 53 is able to pass through the desired position for performing painting or stop at the prescribed position at the desired speed. Note that the arm-use memory can be provided in the painting robot 10, but it can also be located outside the painting robot 10, and it can be possible to perform information transmission and reception with respect to this arm-use memory by means of a wired or wireless communication mechanism (for example, the memory 220 shown in FIG. 2). Figure 8

[0104] In addition, the head control section 130 is a section that controls the operation of the piezoelectric substrate 62 in the painting head unit 50 on the basis of the image processing of the image processing apparatus 200. This head control section 130 controls the ejection of paint on the basis of the divided painting data corresponding to the position when reaching the prescribed position in the trajectory data according to the mechanism for detecting the position of the position sensor 300, the inclination sensor 310, and the like. Note that in this case, the driving frequency of the piezoelectric substrate 62 is controlled to control the number of dots (the number of droplets) ejected from the nozzle 54, or the voltage applied to the piezoelectric substrate 62 is controlled to control the size of the droplets ejected from the nozzle 54, so that the film thickness of the vehicle is uniform.

[0105] In addition, the paint supply control section 140 is a section that controls the supply of paint to the painting head 53, and specifically controls the operation of each working site in the paint supply mechanism 70, such as the supply pump 90, the suction pump 91, the 1st paint regulator 92, the 2nd paint regulator 93, the vacuum pump 97, the three-way valves 77, 79, the on-off valve 78, the switching valve 80, and the like. At this time, it is preferable that the paint supply control section 140 control the operation of the above-described pumps, valves, and the like working sites, so that paint is supplied to the painting head 53 at a constant pressure. However, it can also be that the paint supply control section 140 controls the operation of the above-described pumps, valves, and the like working sites, so that paint is supplied to the painting head 53 at a constant flow rate.

[0106] Here, the paint supply control section 140 is able to access the control-use memory 150, and by this access, is able to read the pressure set value stored in the control-use memory 150 described later.​

[0107] In addition, the position sensor 300 is a sensor that detects the current position of the coating head 53. As the position sensor 300, various sensors such as a rotary encoder, a resolver, a laser sensor, and the like can be used. In addition, the tilt sensor 310 is a sensor that detects the tilt angle of the coating head 53, corresponding to the angle detection mechanism. As the tilt sensor 310, various sensors such as a gyro sensor, an acceleration sensor, a tilt sensor, and the like can be used, for example.

[0108] Next, the details of the paint supply control section 140 will be described. Figure 9 is a diagram showing the outline configuration of the paint supply control section 140. As shown in Figure 9 , the paint supply control section 140 is provided with an adder 141, a feedback control section 142, a feedforward control section 143, and an adder 144. Note that, in Figure 9 , the supply pump 90, the suction pump 91, the first paint regulator 92, and the second paint regulator 93, which are control targets, are set as the control target CT1. In addition, the pressure sensors S1, S2, S4 to S8 are set as the sensor group SG1.

[0109] The adder 141 calculates the difference between the pressure set value read from the control memory 150 and the measured pressure from the sensor group SG1. In the adder 141, in the case where the measured pressure from the sensor group SG1 is equal to the pressure set value, the difference is zero.

[0110] In addition, the feedback control section 142 is a section that calculates a pressure operation value for performing feedback control of the control target CT1, so that the pressure operation value becomes the pressure set value read from the control memory 150 (i.e., so that the difference in the adder 141 is zero, following the pressure set value). Note that the feedback control section 142 is a section that independently performs feedback control based on the pressure set value set for the control target CT1. In the feedback control section 142, by performing, for example, PID control, it is possible to follow well so that each control target CT1 eliminates the difference (deviation) with respect to the pressure set value.

[0111] Note that, in the case where the feedback control section 142 performs, for example, PID control, by setting the prescribed proportional gain Kp, the prescribed differential gain Kd, and the prescribed integral gain Ki to appropriate values, good control can be achieved. In particular, the differential gain Kd contributes to suppressing overshoot and undershoot, and thus it is preferable to be set to an appropriate value.

[0112] Furthermore, the feedforward control unit 143 performs feedforward control of the controlled object CT1 based on the trigger signal sent from the main control unit 110, and calculates the pressure using a compensation pressure value that corresponds to a pressure change in the opposite direction to the expected pressure change relative to the aforementioned pressure setpoint. It should be noted that in this feedforward control unit 143, a signal related to the aforementioned compensation pressure value is sent to the adder 144. The trigger signal will be described later. Alternatively, the trigger signal may also be sent from a component other than the main control unit 110 (e.g., the arm control unit 120, the head control unit 130, etc.).

[0113] In addition, the adder 144 adds the feedback control-related signal from the feedback control unit 142 and the feedforward control-related signal (feedforward compensation) from the feedforward control unit 143 and sends it to the controlled object CT1.

[0114] <About Stress Control>

[0115] The following describes the pressure control in the paint supply control unit 140. Figure 10 This is a graph illustrating an example of the verification results when the controlled object CT1 is controlled solely by feedback control without feedforward control to eject paint from the coating head 53 (nozzle 54). It should be noted that... Figure 10 The diagram shows the state of the piezoelectric substrate 62 being driven at a specified frequency, with the vertical axis representing pressure (bar) and the horizontal axis representing time (s). It should be noted that... Figure 10 The pressure values ​​shown are those measured by pressure sensor S6.

[0116] from Figure 10 As can be seen, a downstroke occurs immediately after the paint is sprayed from the coating head 53, and the pressure inside the nozzle 54 drops significantly. Here, for example, compared with the stable pressure state before spraying (the state in which the paint is in a stable loop in the paint circulation path 71 via the bypass flow path 74 before spraying), the downstroke is approximately 2 kPa.

[0117] On the other hand, an overshoot occurs immediately after the paint is stopped from being sprayed from the coating head 53, resulting in a significant increase in pressure compared to the stable pressure state before spraying. Here, for example, the overshoot amount is approximately 1.5 kPa compared to the stable pressure state before spraying.

[0118] In cases where only feedback control is implemented, Figure 11 The diagram shows an example of a case where a feedforward control unit 143 is provided and feedforward control is performed by the feedforward control unit 143. Figure 11 This is a graph illustrating an example of the verification results of pressure changes when feedforward and feedback control is applied to the controlled object CT1 to spray paint from the coating head 53 (nozzle 54). It should be noted that... Figure 11 In the middle, it is shown that...Figure 10 The case where the piezoelectric substrate 62 is driven at a prescribed frequency is also shown, with the vertical axis indicating pressure (bar) and the horizontal axis indicating time (s). Also, Figure 11 the pressure value in the Figure 10 is also the pressure value measured by the pressure sensor S6.

[0119] Also, in the verification results shown in Figure 11 , the goal is to suppress both undershoot and overshoot. Therefore, in order to suppress undershoot, a compensation pressure value is calculated by the feedforward control section 143 based on a trigger signal (associated with the start of spraying) at the time of the start of spraying from the state where spraying of paint from the painting head 53 is stopped, and this compensation pressure value is added to the pressure calculation value from the feedforward control section 143 using the adder 144, thereby performing control of the control target CT1. Also, in order to suppress overshoot, a compensation pressure value is calculated by the feedforward control section 143 based on a trigger signal (associated with the stop of spraying) at the time of the stop of spraying from the state where spraying of paint from the painting head 53 is performed, and this compensation pressure value is added to the pressure calculation value from the feedforward control section 143 using the adder 144, thereby performing control of the control target CT1.

[0120] That is, in order to suppress both undershoot and overshoot, feedback control and feedforward control are combined, and control of the control target CT1 is performed. However, in Figure 11 , in order to suppress only undershoot, control combining feedback control and feedforward control can be performed based on a trigger signal at the time when spraying of paint from the painting head 53 is started. Also, in order to suppress only overshoot, control combining feedback control and feedforward control can be performed based on a trigger signal at the time when spraying of paint from the painting head 53 is stopped.

[0121] In Figure 11 , for example, compared to the state where the pressure is stable before spraying (a state where paint is stably circulated in the paint circulation path 71 via the bypass flow path 74 without spraying), undershoot is effectively suppressed to about 1 kPa or less. That is, the feedforward control section 143 is provided in addition to the feedback control section 142, control of the control target CT1 is performed by combining feedback control and feedforward control, and compared to the case shown in Figure 10 , undershoot is drastically reduced. Also, in Figure 11 , for example, compared to the state where the pressure is stable before spraying (a state where paint is stably circulated in the paint circulation path 71 via the bypass flow path 74 without spraying), overshoot is effectively suppressed to about 1 kPa or less. That is, the feedforward control section 143 is provided in addition to the feedback control section 142, control of the control target CT1 is performed by combining feedback control and feedforward control, and compared to the case shown in Figure 10 , overshoot is drastically reduced.

[0122] According to the verification results shown in Figure 10 Figure 11 According to the verification results shown in

[0123] In addition, in Figure 11

[0124] Here, as the trigger signal transmitted from the main control section 110 to the feedforward control section 143, in the case where it is desired to suppress undershoot and / or overshoot, for example, a signal related to the start of ejection of the coating head 53 can be cited. However, the trigger signal is not limited to this, and, for example, a prescribed position on the movement path of the coating head 53 based on the robot teaching operation by the robot arm Rl can be set as the trigger signal. Figure 12 is a diagram showing a case where the arrival of the coating head 53 at a prescribed position on the movement path is the trigger signal.

[0125] In Figure 12

[0126] Note that, in Figure 12

[0127] ​​​​Further, in the painting path in which the painting head 53 moves from the position P14 to the position P21 and then moves from the position P21 toward the position P24, the position information of the position sensor 300 at the time of reaching the position P22 is used as a trigger signal to implement undershoot suppression, and further, the position information of the position sensor 300 at the time of reaching the position P23, which is just before the end of painting, is used as a trigger signal to implement overshoot suppression.

[0128] Similarly, in the painting path in which the painting head 53 moves from the positions P24, P34, P44, P54, and P64 to the positions P31, P41, P51, P61, and P71, respectively, and then moves from the positions P31, P41, P51, P61, and P71 toward the positions P34, P44, P54, P64, and P74, respectively, the position information of the position sensor 300 at the time of reaching the positions P32, P42, P52, P62, and P72 is used as a trigger signal to implement undershoot suppression, and further, the position information of the position sensor 300 at the time of reaching the positions P33, P43, P53, P63, and P73, which is just before the end of painting, is used as a trigger signal to implement overshoot suppression.

[0129] Note that, in actual painting, the ejection of the paint droplets from the painting head 53 is stopped, and even if overshoot occurs, the ejection of the paint droplets is not performed for a prescribed period of time thereafter, so that undershoot can be effectively suppressed. Therefore, in the undershoot suppression control shown in Figure 12 , overshoot suppression can also be implemented using the position information of the position sensor 300 at the time of reaching the positions P13, P23, P33, P43, P53, P63, and P73 as a trigger signal.

[0130] Further, as shown in Figure 13 , if the robot arm R1 changes in posture to be inclined at an angle θ1, the difference in height of the supply pump 90, the suction pump 91, the first paint conditioner 92, and the second paint conditioner 93 changes drastically, and the above-described undershoot and overshoot can occur. Therefore, for example, based on robot teaching, in a case where it is possible to predict that the posture of the robot arm R1 changes after a prescribed time point based on the position information of the position sensor 300 corresponding to the reaching of the painting head 53 to a prescribed spatial position coordinate, the detection of the reaching of a prescribed position by the position sensor 300 can be used as a trigger signal. Further, for example, based on robot teaching, in a case where it is possible to predict that the posture of the robot arm R1 changes after a prescribed time point based on the information of the inclination angle of the inclination sensor 310, the detection of the reaching of a prescribed inclination angle by the inclination sensor 310 can be used as a trigger signal.

[0131] Note that, in the above-described Figure 13The case where the painting head 53 is tilted due to a change in the posture of the robot arm R1 is shown in FIG. 1, but in the case where the painting head 53 is not tilted and the robot arm R1 changes in posture, the trigger signal can also be set as described above.

[0132] (2. Regarding Effects)

[0133] As described above, the painting robot 10 that performs FR painting of a vehicle includes: a painting head unit 50 that has a plurality of nozzles 54 that eject paint droplets and a painting head 53 that has a piezoelectric substrate 62 that extrudes droplets from the nozzles 54 by being driven; a robot arm R1 that mounts the painting head unit 50 at a front end and moves the painting head unit 50 to a desired position; a paint supply mechanism 70 that is disposed across between the robot arm R1 and the painting head unit 50; and a control section 100 that controls driving of the robot arm R1 and the paint supply mechanism 70.

[0134] Further, the paint supply mechanism 70 includes: a paint circulation path 71 that is disposed across between the robot arm R1 and the painting head unit 50, supplies paint to the painting head 53, and recovers paint that is not ejected from the painting head 53; a supply pump 90 and / or a suction pump 91 (paint transfer mechanism) that is disposed midway through the paint circulation path 71 and performs supply and recovery of paint between a paint storage site and the painting head 53; and a first paint regulator 92 and / or a second paint regulator 93 (regulating valve) that is disposed midway through the paint circulation path 71 and can regulate opening and closing of an internal flow path of the paint circulation path 71, and the control section 100 includes: a control memory 150 that stores a pressure set value; a feedback control section 142 that calculates a pressure calculation value for performing feedback control of the action of at least one of the supply pump 90 and / or the suction pump 91 (paint transfer mechanism) and the first paint regulator 92 and / or the second paint regulator 93 (regulating valve) to become the pressure set value read from the control memory 150, and controls the action of at least one of the supply pump 90 and / or the suction pump 91 (paint transfer mechanism) and the first paint regulator 92 and / or the second paint regulator 93 (regulating valve); and a feedforward control section 143 that corrects the pressure calculation value by a compensation pressure value in a direction opposite to an expected change in pressure with respect to a change in pressure from the pressure set value based on a trigger signal associated with a change in the state of the painting head 53, and controls the action of at least one of the supply pump 90 and / or the suction pump 91 (paint transfer mechanism) and the first paint regulator 92 and / or the second paint regulator 93 (regulating valve).

[0135] As such, the control section 100 includes the feedback control section 142 and the feedforward control section 143. Therefore, when feedback control is performed on at least one of the (paint transfer mechanism) of the supply pump 90 and / or the suction pump 91 and the 1st paint regulator 92 and / or the 2nd paint regulator 93 (regulator valve) so as to become a pressure set value, in the case where undershoot, overshoot, and the like of the pressure change are predicted, the feedforward control section 143 can perform an operation of a compensation pressure value in the opposite direction of the pressure change, and by correcting the pressure operation value with the compensation pressure value, the pressure change can be suppressed.

[0136] Therefore, it is possible to reduce the influence of undershoot, overshoot, and the like of the pressure change. Thus, it is possible to stabilize the ejection pressure when, for example, the paint is ejected from the painting head 53, and it is possible to continuously perform the paint ejection. That is, it is possible to prevent the occurrence of an unstable paint ejection state including a state in which the paint is not ejected due to a decrease in the pressure in the painting head 53, or the occurrence of a defect such as overflow of the paint from the nozzle 54 due to an increase in the pressure in the painting head 53. Thus, it is possible to prevent the nozzle formation surface 52 of the painting head 53 from being contaminated or the like, and to prevent a defect such as the inability to perform painting of the next vehicle or the like.

[0137] In addition, in the present embodiment, the paint circulation path 71 includes a paint supply passage 72 that supplies the paint to the painting head 53, and a return flow path 73 that is connected to the paint discharge side of the painting head 53 and recovers the paint that is not ejected from the nozzle 54. Furthermore, the paint transfer mechanism includes a supply pump 90 (paint supply unit) that is mounted at a prescribed position of the robot arm R1, is provided midway through the paint supply passage 72, and applies a pressure for supplying the paint to the painting head 53 based on the control of the control section 100, and a suction pump 91 (paint recovery mechanism) that is mounted at a prescribed position of the robot arm R1, is provided midway through the return flow path 73, and applies a pressure for recovering the paint that is not ejected from the painting head 53 to the downstream side of the return flow path 73 based on the control of the control section 100, and the feedforward control section 143 can correct the pressure operation value with a compensation pressure value that corrects the supply pump 90 (paint supply unit) to the increase side of the drive based on a trigger signal associated with the start of the ejection from the state in which the painting head 53 stops the ejection of the paint, and cause the supply pump 90 (paint supply unit) to operate.

[0138] As such, for the supply pump 90 (paint supply unit), the operation of the compensation pressure value is performed by the feedforward control section 143 based on the trigger signal associated with the start of the ejection from the state in which the painting head 53 stops the ejection of the paint, and the pressure operation value is corrected with the compensation pressure value, and by combining such feedback control and feedforward control, it is possible to reduce the influence of the decrease in the pressure at the start of the paint ejection.

[0139] Further, in the present embodiment, the feedforward control section 143 is able to correct the pressure calculation value with a compensation pressure value that corrects the (paint supply unit) supply pump 90 to the drive stop side based on a trigger signal associated with a change in the state of the paint ejection from the paint ejection head 53, and operate the (paint supply unit) supply pump 90.

[0140] In this way, with respect to the (paint supply unit) supply pump 90, the feedforward control section 143 performs calculation of a compensation pressure value based on a trigger signal associated with a change in the state of the paint ejection from the paint ejection head 53, and corrects the pressure calculation value with this compensation pressure value, and by performing such control that combines feedback control and feedforward control, it is possible to reduce the influence of the pressure drop at the time of the start of the paint ejection.

[0141] Further, in the present embodiment, the feedforward control section 143 is able to correct the pressure calculation value with a compensation pressure value that corrects the (paint supply unit) supply pump 90 to the drive stop side based on a trigger signal associated with a change in the state of the paint ejection from the paint ejection head 53, and operate the (paint supply unit) supply pump 90.

[0142] In this way, with respect to the (paint supply unit) supply pump 90, the feedforward control section 143 performs calculation of a compensation pressure value based on a trigger signal associated with a change in the state of the paint ejection from the paint ejection head 53, and corrects the pressure calculation value with this compensation pressure value, and by performing such control that combines feedback control and feedforward control, it is possible to reduce the influence of the pressure drop at the time of the start of the paint ejection.

[0143] Further, in the present embodiment, the feedforward control section 143 is able to correct the pressure calculation value with a compensation pressure value that corrects the (paint supply unit) supply pump 90 to the drive stop side based on a trigger signal associated with a change in the state of the paint ejection from the paint ejection head 53, and operate the (paint supply unit) supply pump 90.

[0144] In this way, with respect to the (paint supply unit) supply pump 90, the feedforward control section 143 performs calculation of a compensation pressure value based on a trigger signal associated with a change in the state of the paint ejection from the paint ejection head 53, and corrects the pressure calculation value with this compensation pressure value, and by performing such control that combines feedback control and feedforward control, it is possible to reduce the influence of the pressure drop at the time of the start of the paint ejection.

[0145] Further, in the present embodiment, the adjusting valve includes a first paint adjuster 92 (first adjusting valve) provided on a downstream side of the paint supply passage 72 as compared with the supply pump 90 (paint supply unit) and adjusting a pressure of the paint toward the painting head 53 based on a control of the control section 100, and a second paint adjuster 93 (second adjusting valve) provided on an upstream side of the return flow path 73 as compared with the suction pump 91 (paint recovery mechanism) and adjusting a pressure of the paint recovered from the painting head 53 based on a control of the control section 100. Further, the feedforward control section 143 can correct the pressure operation value by a compensation pressure value based on a trigger signal associated with a start of the ejection from the state where the ejection of the paint from the painting head 53 is stopped or a stop of the ejection from the state where the paint is ejected from the painting head 53, and control an operation of at least one of the first paint adjuster 92 (first adjusting valve) and the second paint adjuster 93 (second adjusting valve).

[0146] As such, based on the trigger signal associated with the start of the ejection from the state where the ejection of the paint from the painting head 53 is stopped or based on the trigger signal associated with the stop of the ejection from the state where the paint is ejected from the painting head 53, the feedforward control section 143 operates the compensation pressure value, and corrects the pressure operation value with the compensation pressure value, and by performing such control of combining the feedback control and the feedforward control with respect to at least one of the first paint adjuster 92 (first adjusting valve) and the second paint adjuster 93 (second adjusting valve), it is possible to reduce the influence of the pressure reduction at the start of the ejection of the paint.

[0147] Further, in the present embodiment, the feedforward control section 143 can correct the pressure operation value by a compensation pressure value that corrects the first paint adjuster 92 (first adjusting valve) to the open side based on the trigger signal associated with the start of the ejection from the state where the ejection of the paint from the painting head 53 is stopped, and cause the first paint adjuster 92 (first adjusting valve) to operate.

[0148] As such, with respect to the first paint adjuster 92 (first adjusting valve), based on the trigger signal associated with the start of the ejection from the state where the ejection of the paint from the painting head 53 is stopped, the feedforward control section 143 operates the compensation pressure value, and corrects the pressure operation value with the compensation pressure value, and by performing such control of combining the feedback control and the feedforward control, it is possible to reduce the influence of the pressure reduction at the start of the ejection of the paint.

[0149] Further, in the present embodiment, the feedforward control section 143 can correct the pressure operation value by a compensation pressure value that corrects the second paint adjuster 93 (second adjusting valve) to the close side based on the trigger signal associated with the start of the ejection from the state where the ejection of the paint from the painting head 53 is stopped, and cause the second adjusting valve to operate.

[0150] In this way, with respect to the 2nd paint regulator 93 (2nd regulating valve), based on the trigger signal associated with the change from the state in which the paint is being ejected from the painting head 53 to the state in which the ejection is stopped, the feedforward control section 143 performs the operation of the compensation pressure value, and corrects the pressure operation value with the compensation pressure value, and by performing such control that combines the feedback control and the feedforward control, it is possible to reduce the influence of the pressure drop at the time of the start of the ejection of the paint.

[0151] In addition, in the present embodiment, the feedforward control section 143 is able to correct the pressure operation value with the compensation pressure value that corrects the 1st paint regulator 92 (1st regulating valve) to the closing side, based on the trigger signal associated with the change from the state in which the paint is being ejected from the painting head 53 to the state in which the ejection is stopped, and to control the operation of the 1st paint regulator 92 (1st regulating valve).

[0152] In this way, with respect to the 1st paint regulator 92 (1st regulating valve), based on the trigger signal associated with the change from the state in which the paint is being ejected from the painting head 53 to the state in which the ejection is stopped, the feedforward control section 143 performs the operation of the compensation pressure value, and corrects the pressure operation value with the compensation pressure value, and by performing such control that combines the feedback control and the feedforward control, it is possible to reduce the influence of the pressure rise at the time of the stop of the ejection of the paint.

[0153] In addition, in the present embodiment, the feedforward control section 143 is able to correct the pressure operation value with the compensation pressure value that corrects the 2nd paint regulator 93 (2nd regulating valve) to the opening side, based on the trigger signal associated with the change from the state in which the paint is being ejected from the painting head 53 to the state in which the ejection is stopped, and to control the operation of the 2nd paint regulator 93 (2nd regulating valve).

[0154] In this way, with respect to the 2nd paint regulator 93 (2nd regulating valve), based on the trigger signal associated with the change from the state in which the paint is being ejected from the painting head 53 to the state in which the ejection is stopped, the feedforward control section 143 performs the operation of the compensation pressure value, and corrects the pressure operation value with the compensation pressure value, and by performing such control that combines the feedback control and the feedforward control, it is possible to reduce the influence of the pressure rise at the time of the stop of the ejection of the paint.

[0155] In addition, in the present embodiment, the feedforward control section 143 is able to correct the pressure operation value with the compensation pressure value that corrects the 2nd paint regulator 93 (2nd regulating valve) to the opening side, based on the trigger signal associated with the change from the state in which the paint is being ejected from the painting head 53 to the state in which the ejection is stopped, and to control the operation of the 2nd paint regulator 93 (2nd regulating valve).

[0156] In this way, based on the trigger signal associated with the change in the posture of the coating head 53, the feedforward control section 143 performs the operation of the compensation pressure value, and corrects the pressure operation value with the compensation pressure value, and by performing such control that combines feedback control and feedforward control, it is possible to reduce the influence of the change in the pressure when the posture of the coating head 53 changes.

[0157] (3. Variations)

[0158] The above describes one embodiment of the present application, but the present application can be varied in many ways other than the above-described embodiment. Variations are described below.

[0159] In the above-described embodiment, a configuration including the pressure sensors S1 to S8 and the first flowmeter FM1 and the second flowmeter FM2 is adopted. However, in the case where the first flowmeter FM1 and the second flowmeter FM2 are provided, at least one of the pressure sensors S1 to S8 can be omitted, and in the case where the pressure sensors S1 to S8 are provided, at least one of the first flowmeter FM1 and the second flowmeter FM2 can be omitted.

Claims

1. A painting robot, characterized in that, To paint the vehicles, The painting robot includes: A coating head unit having a coating head having multiple nozzles that spray droplets of paint. A robotic arm that mounts the coating head unit to its front end and moves the coating head to a desired position; A paint supply mechanism, which spans between the robotic arm and the coating head unit; and The control unit controls the drive of the robotic arm and the drive of the paint supply mechanism. The paint supply organization includes: A paint circulation path, which spans between the robotic arm and the painting head unit, supplies paint to the painting head and recovers paint that is not sprayed from the painting head; A paint transfer mechanism, positioned midway through the paint circulation path, supplies and recovers the paint between the paint storage area and the coating head; and A regulating valve, located midway through the paint circulation path, is capable of regulating the opening and closing of the internal flow path of the paint circulation path. The control unit includes: A control memory that stores pressure setpoints; A feedback control unit calculates a pressure calculation value and controls the action of at least one of the paint transfer mechanism and the regulating valve, wherein the pressure calculation value is used to perform feedback control of the action of at least one of the paint transfer mechanism and the regulating valve, so as to become the pressure setpoint read from the control memory; and The feedforward control unit, based on a trigger signal associated with a change in the state of the coating head, corrects the calculated pressure value with a compensation pressure value that corresponds to a pressure change in the opposite direction to the expected pressure change relative to the pressure setpoint, and controls the operation of at least one of the paint transfer mechanism and the regulating valve. The coating circulation path includes: A paint supply passage that supplies paint to the coating head; and The return flow path, connected to the paint discharge side of the coating head, recovers any paint that was not sprayed from the nozzle. The coating transfer mechanism includes: A paint supply unit, mounted at a predetermined position on the robotic arm, is positioned midway through the paint supply path and applies pressure to supply paint to the coating head based on the control of the control unit; and A paint recovery mechanism, mounted at a predetermined position on the robotic arm, is positioned midway through the return flow path. Based on the control of the control unit, pressure is applied downstream of the return flow path to recover any paint not sprayed from the coating head. The feedforward control unit corrects the calculated pressure value by adjusting the compensation pressure value of the paint supply unit to the drive increase side based on the trigger signal associated with the start of spraying, and causes the paint supply unit to operate, wherein the start of spraying is the start of spraying from the state change of the coating head stopping spraying the paint.

2. The painting robot according to claim 1, characterized in that, The feedforward control unit, based on a trigger signal associated with the start of spraying, corrects the calculated pressure value by adjusting the compensation pressure value of the paint recovery mechanism towards the drive reduction side, and activates the paint recovery mechanism, wherein the start of spraying is the start of spraying from the state change of the coating head stopping spraying the paint.

3. The painting robot according to claim 1 or 2, characterized in that, The feedforward control unit corrects the pressure calculation value by adjusting the compensation pressure value of the paint supply unit to the drive stop side based on the trigger signal associated with the spray stop, and causes the paint supply unit to operate, wherein the spray stop is a spray stop due to a change in the state of the paint being sprayed from the coating head.

4. The painting robot according to claim 1 or 2, characterized in that, The feedforward control unit, based on a trigger signal associated with spray stop, corrects the calculated pressure value by adjusting the compensation pressure value of the paint recovery mechanism to the drive-in side, and activates the paint recovery mechanism, wherein the spray stop is a spray stop resulting from a change in the state of the paint being sprayed from the coating head.

5. The painting robot according to claim 1 or 2, characterized in that, The regulating valve includes: A first regulating valve, located downstream of the paint supply unit in the paint supply passage, regulates the pressure of the paint towards the coating head based on the control of the control unit; and A second regulating valve, located upstream of the paint recovery mechanism, regulates the pressure of the paint recovered from the coating head based on the control of the control unit. The feedforward control unit corrects the calculated pressure value with the compensated pressure value based on the trigger signal associated with the start or stop of spraying, and controls the operation of at least one of the first regulating valve and the second regulating valve, wherein the start of spraying is the start of spraying from the state change of the coating head stopping the spraying of the paint, and the stop of spraying is the stop of spraying from the state change of the spraying of the paint.

6. The painting robot according to claim 5, characterized in that, The feedforward control unit corrects the calculated pressure value by adjusting the compensation pressure value that corrects the first regulating valve to the open side based on the trigger signal associated with the start of spraying, and actuates the first regulating valve, wherein the start of spraying is the start of spraying from the state change of the coating head stopping spraying the paint.

7. The painting robot according to claim 5, characterized in that, The feedforward control unit corrects the calculated pressure value by adjusting the compensation pressure value that corrects the second regulating valve toward the closed side based on the trigger signal associated with the start of spraying, and actuates the second regulating valve, wherein the start of spraying is the start of spraying from the state change of the coating head stopping spraying the paint.

8. The painting robot according to claim 5, characterized in that, The feedforward control unit corrects the calculated pressure value by adjusting the compensation pressure value that corrects the first regulating valve toward the closed side based on the trigger signal associated with the spray stop, and actuates the first regulating valve, wherein the spray stop is a spray stop due to a change in the state of the paint being sprayed from the coating head.

9. The painting robot according to claim 5, characterized in that, The feedforward control unit corrects the calculated pressure value by adjusting the compensation pressure value that corrects the second regulating valve to the open side based on the trigger signal associated with the spray stop, and actuates the second regulating valve, wherein the spray stop is a spray stop due to a change in the state of the paint being sprayed from the coating head.

10. The painting robot according to claim 1 or 2, characterized in that, The feedforward control unit, based on a trigger signal associated with the attitude change of the coating head, corrects the calculated pressure value with a compensation pressure value in the opposite direction to the expected pressure change relative to the pressure setpoint, and controls the operation of at least one of the paint transfer mechanism and the regulating valve.

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