JPH06285402A - Method of controlling rate of flow of sealing agent in sealing robot - Google Patents

Abstract

PURPOSE:To seal all sections of a course with stable bead thickness by controlling the speed of revolution of a sealing agent supplying pump by a speed instruction which is obtained by multiplying the moving speed of a robot by a prescribed proportional gain and carrying out feedback control to make the detected pressure of a sealing gun be a set pressure when no sealing is carried out. CONSTITUTION:To control the flow rate of a sealing agent of a sealing robot a motor 30a for a sealing agent supplying pump is connected with an additional shaft controlling circuit 17 of a robot controlling apparatus 10 and when sealing is carried out, the speed of revolution of the motor 30a for the sealing agent supplying pump is controlled by the robot controlling apparatus 10 based on the speed instruction which is obtained by multiplying the moving speed of a robot main body 20 by a prescribed proportional gain and thus the sealing agent is supplied to a sealing gun 30b attached to the robot. When no sealing is carried out, the pressure of the sealing agent is detected by a pressure sensor 40 installed in the sealing gun 30b and the driving torque of the motor 30a is controlled based on feedback data to make the detected pressure be a set pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a flow rate of a sealing agent which allows a robot to perform a sealing operation.

[0002]

2. Description of the Related Art A seal gun is attached to a wrist at the end of a robot arm to teach a robot a sealing operation,
It is common practice to perform sealing work by robots. Conventionally, the control of the sealing work by this robot is provided with a sealant supply control device separately from the robot control device, and based on a control signal such as a seal start or stop command from the robot control device, the sealant is supplied. The supply control device controls the sealant supply pump. In addition, there are two types of seal guns, one that applies the sealant using a rod-shaped nozzle and the other that uses a spray nozzle.The former is used to apply the sealant linearly to the target object, and the latter is a planar object. It is used when a sealant is applied to the surface.

[0003]

In a seal gun having a rod-shaped nozzle, it is generally necessary to make the speed control of the sealant supply pump proportional to the moving speed of the robot because it is necessary to keep the bead thickness constant when the robot moves. However, the internal pressure of the seal gun is not actively controlled. Therefore, there is a problem in that the internal pressure of the seal gun immediately before the nozzle shutter of the seal gun is opened, that is, the jetting force of the sealant at the start of application varies, and the bead film thickness becomes unstable. For example, as shown in FIG. 6, the first sealing operation start position P
Teaching position section P1 until the wrist of the robot moves to 2
Even if the internal pressure Ps of the seal gun can be maintained at the initial blast pressure adapted to the robot moving speed in the section P2-P3 in -P2, the first sealing operation is completed at the teaching position P3 and the seal gun If the sealant supply pump causes overtravel due to inertia when the nozzle shutter is closed, the internal pressure of the seal gun rises more than necessary, and the sealant is removed at the moment when the nozzle shutter is opened at the second sealing operation start position P4. There is a risk that the bead will become thicker by ejecting strongly. In addition, since the internal pressure of the seal gun is not actively controlled, if it is absolutely necessary to prevent the bead film thickness from increasing at the start position of the second and subsequent sealing operations, the sealant inside the seal gun is purged. Then, it becomes necessary to reduce the pressure, but it is not possible to inadvertently scatter the sealant.

On the other hand, in a seal gun equipped with a spray nozzle, the bead width of the seal agent is maintained by controlling the driving force of the seal agent supply pump, that is, the internal pressure of the seal gun so as to always keep a constant value. However, immediately after the nozzle shutter of the seal gun is opened, that is, at the start of coating, the internal pressure of the seal gun is temporarily lowered, so that there is a problem that the bead width immediately after the start of sealing is reduced. For example, as shown in FIG. 7, the teaching position section Q1-Q2 until the wrist of the robot moves to the first sealing operation start position Q2, the teaching position section Q2-Q3 of the first sealing operation, and the teaching position section Q2-Q3. The teaching position section Q3-Q4 from the first sealing operation completion position Q3 to the second sealing operation start position Q4 until the wrist of the robot moves, and the teaching position section Q4-Q5 of the second sealing operation. Even if the internal pressure of the seal gun as a whole can be maintained at a constant value Ps,
Immediately after opening the nozzle shutter at the teaching positions Q2 and Q4, the internal pressure of the seal gun always temporarily drops. Since there is a time delay until the internal pressure of the seal gun returns to the set value Ps again by compensating for this pressure drop, the bead width immediately after the start of sealing may decrease.

Further, in each of these cases, a constant gain is always used as a proportional gain for speed control and a set value for pressure control. Therefore, the bead thickness and width are changed by a robot teaching program. I couldn't do that.

Therefore, an object of the present invention is to eliminate these drawbacks of the prior art, to obtain a stable bead width and film thickness, and to control the bead width and film thickness sealing conditions by a robot teaching program. It is an object of the present invention to provide a method for controlling the flow rate of a sealant in a sealing robot, which can be arbitrarily set for each teaching section.

[0007]

A sealant supply pump is connected to an additional axis control circuit of a robot controller, and a pressure sensor for detecting the pressure of the sealant is provided on the seal gun.

In the case of a seal gun that applies a sealant using a rod-shaped nozzle, the seal gun is controlled by controlling the rotation speed of the motor of the sealant supply pump with a speed command obtained by multiplying the moving speed of the robot by a predetermined proportional gain when performing sealing. While supplying the sealant to the sealant, when the sealing is not performed, the pressure of the sealant is detected by the pressure sensor provided in the seal gun, and the drive torque of the motor is feedback-controlled so that the detected pressure becomes the set pressure. Obtain a stable bead thickness. Further, by setting the proportional gain and the set pressure of the sealant in the teaching program corresponding to the robot teaching position in the sealing operation, the bead film thickness can be arbitrarily changed for each teaching section.

In the case of a seal gun in which the sealant is applied with a spray nozzle, the set pressure of the sealant when the sealing is performed and the set pressure of the sealant when the sealing is not performed are set in the robot controller separately, and the seal gun is set. The pressure of the sealant is sequentially detected by the pressure sensor provided at the position, and the driving torque of the motor of the sealant supply pump is feedback-controlled so that the detected pressure becomes the set pressure, thereby obtaining a stable bead width. Also,
By setting the set pressure of the sealant in the teaching program corresponding to the robot teaching position in the sealing operation, the bead width can be arbitrarily changed for each teaching section.

[0010]

In the seal gun equipped with the rod-shaped nozzle, the seal agent is supplied to the seal gun by controlling the rotation speed of the motor of the seal agent supply pump by a speed command obtained by multiplying the moving speed of the robot by a predetermined proportional gain. The amount of the sealant applied per unit distance of the object is maintained at a constant value regardless of the moving speed of the robot, and the bead film thickness is maintained at a value corresponding to the proportional gain. In addition, since the drive torque of the motor is feedback controlled so that the pressure of the sealant detected by the pressure sensor becomes the set pressure when the sealing is not executed, the initial dynamic pressure of the sealant at the start of sealing is stable and immediately after the start of sealing. The bead thickness is stable. The bead film thickness can be arbitrarily set by writing the proportional gain and the set pressure of the sealant in the teaching program corresponding to the robot teaching position in the sealing operation.

In the seal gun equipped with the spray nozzle, the set pressure of the sealant when the sealing is performed and the set pressure of the sealant when the sealing is not performed are set separately in the robot controller, so that the seal is not performed. The initial pressure at the start of sealing can be increased by setting the set pressure at the time higher. Therefore, it is possible to prevent the initial dynamic pressure at the start of sealing from falling below the set pressure of the sealing agent at the time of performing sealing, and in the state in which the pressure drop accompanying the opening of the nozzle shutter is compensated for, the bead immediately after the start of sealing is It is possible to prevent the width from decreasing. Further, the pressure of the sealant is sequentially detected by the pressure sensor provided in the seal gun, and the drive torque of the motor of the sealant supply pump is feedback-controlled so that the detected pressure becomes the set pressure. The width is stable. The width of the bead can be arbitrarily set by writing the set pressure of the sealant in the teaching program corresponding to the robot teaching position in the sealing operation.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a main part of a sealing robot for carrying out an embodiment of the present invention. A robot controller 10 includes a processor (CPU) 11, a ROM 12 for storing a control program, a RAM 13 used for temporary storage of data, a non-volatile memory 14 for storing a teaching program, and a teaching operation panel 15 with a display device. An axis control circuit 16 for driving and controlling a drive source (servo motor) for each axis of the robot, an additional axis control circuit 17 and an input / output interface 18 additionally provided for controlling axes other than each axis of the robot. Bus connected. Further, each axis drive source (servo motor) of the robot body 20 is connected to the axis control circuit 16, and the motor 30a of the sealant supply pump for supplying the sealant to the seal gun 30b is connected to the additional axis control circuit 17. Has been done. The seal gun 30b is attached to the wrist at the end of the arm of the robot body 20, and a pressure sensor 40 for detecting the pressure of the sealant is attached to the end of the seal gun 30b.
Is connected to the analog input terminal of the input / output interface 18 in the robot controller 10. Further, the seal gun 30b is turned on / off with the discharge of the sealing agent.
There is a nozzle shutter for FF control, which is controlled by a solenoid valve. This solenoid valve is connected to the input / output interface 18 and controlled by the robot controller 10.

Next, a stick-shaped nozzle-type seal gun 3
0b is attached to the robot wrist to perform a sealing operation. The processor 1 of the robot controller shown in FIG.
A description will be given with reference to a flowchart of a process performed by 1 in every predetermined cycle.

First, for the robot, the seal gun 30
It is assumed that the movement route of b is taught in advance and the motion teaching program is already stored in the non-volatile memory 14.
Further, in the teaching program, control data of a moving section corresponding to each teaching position of the moving route is set as a program in accordance with each teaching position. That is, if the movement section is the sealing execution section, the value of the speed control proportional gain for controlling the rotation speed of the motor 30a of the sealant supply pump in correspondence with the desired bead film thickness corresponds to the teaching position. If the moving section is set and the sealing section is a non-sealing section, the target pressure value of the sealant pressure control is programmed corresponding to the taught position, and the speed control proportional gain and target value are set. The value of the pressure is sequentially stored in the RAM 13 each time the current position of the robot reaches each teaching position.
It is adapted to be updated and stored in each of the speed control proportional gain storage register k2 and the target value storage register Ps. Since the speed control proportional gain and the pressure that is the target value are not used at the same time, the speed control proportional gain storage register k2 and the target value storage register Ps may be substantially the same register.

FIG. 4 is a conceptual diagram showing an example of the correspondence between the teaching position of the moving route and the sealing execution section. In this example, the teaching position sections P2-P3 and P4-P5 are the sealing execution section and the teaching execution section. Position section P1-P2, P3
-P4 is a sealing non-execution section for positioning movement. As described above, speed control is performed in the sealing execution section to control the rotation speed of the motor 30a of the sealant supply pump in accordance with the desired bead thickness, and in the sealing non-execution section. The pressure control is performed to adapt the pressure of 1 to the initial motion pressure of the next sealing execution section. For example, the target values of the sealant pressure in the non-sealing sections P1-P2 and P3-P4 are programmed corresponding to the teaching positions P1 and P3, respectively, and the bead film in the sealing execution sections P2-P3 and P4-P5 is set. The velocity control proportional gain corresponding to the thickness is programmed in correspondence with the teaching positions P2 and P4. As described above, the value of the velocity control proportional gain in the sealing execution section is determined corresponding to the desired bead thickness, and the pressure control target value in the sealing non-execution section is required in the next sealing execution section. These values are set in advance on the teaching program corresponding to each teaching position.

When the operation start command is input, the processor 1
1 is to sequentially read the teaching program block by block at a predetermined cycle, drive the servo motor of each axis of the robot body 20 via the axis control circuit 16 to drive the robot, and move the seal gun 30b along the teaching path. Further, as described above, each time the current position of the seal gun 30b reaches each teaching position, the speed control proportional gain and the pressure value which is the target value are sequentially set to the speed control proportional gain storage register k2 and the target in the RAM 13. It will be updated and stored in each of the value storage registers Ps. When a sealing start command is read from the teaching program, the solenoid valve of the seal gun 30b is operated via the input / output interface 18 to open the nozzle shutter and set the flag F to "1". When the sealing end command is read, the solenoid valve is deactivated and the nozzle shutter is closed, and the flag F is set to "0". Further, the processor 11 performs a predetermined cycle (for example, a cycle synchronized with a distribution cycle for distributing a movement command to each axis of the robot) as shown in FIG.
The process of is executed.

First, it is judged whether or not the flag F is set to "1" (step a1). If "1" is not set in the flag F, it means that the seal gun 30b is moving in the sealing non-execution section with the nozzle shutter closed, and the flag F is "1".
If is set, it means that the seal gun 30b is performing the sealing operation while moving in the sealing execution section.

Therefore, when the flag F is not set to "1" and the determination result of step a1 is true, the processor 11 first reads the current pressure Pn of the sealant from the pressure sensor 40 (step a2). ), The detected pressure Pn is subtracted from the target pressure value Ps of the positioning movement section stored in the target value storage register of the RAM 13, and this value is further multiplied by a set proportional gain k1 for pressure control to obtain a sealant supply pump. The speed command Vc of the motor 30a is calculated (step a3), and the speed command Vc is added to the additional axis control circuit 1
7 (step a4) to drive the motor 30a of the sealant supply pump. Hereinafter, while the flag F is set to “0”, that is, while the seal gun 30b moves in the sealing non-execution section, the processor 11 executes the processing of step a1 to step a4 every predetermined period, and the seal gun 30b is operated. The rotation speed of the motor 30a of the sealant supply pump is feedback-controlled so that the sealant pressure at the tip matches the set value Ps of the target value storage register.
By the time the seal gun 30b reaches the next taught position, the current pressure Pn of the sealant rises or falls to match the target pressure value Ps.

For example, the seal gun 30b is currently shown in FIG.
If the target pressure read from the target value storage register of the RAM 13 is the value corresponding to the teaching position P1, that is, the teaching position that is the start position of the next sealing execution section, This is the value of the initial pressure required at P2, and when the seal gun 30b reaches the teaching position P2, the current pressure Pn of the sealant is present.
Has already coincided with the initial dynamic pressure Ps required at the taught position P2.

When the seal gun 30b reaches the next teaching position and the sealing start command is read from the teaching program, the solenoid valve operates and the nozzle shutter is opened as described above, and the movement path of the seal gun 30b is changed. Enter the ceiling execution section. At this time, the flag F is set to "1", so that the determination result of step a1 becomes false. Therefore, the processor 11 reads the speed command Vr after the acceleration / deceleration processing performed before performing the pulse distribution of the movement command to each axis of the robot, and the sealing stored in the speed control proportional gain storage register in the RAM 13. The speed command proportional gain k2 of the execution section is multiplied by the speed command Vr to obtain the speed command Vc of the motor 30a of the sealant supply pump corresponding to the bead film thickness specified in the sealing execution section (step a5). The speed command Vc is output to the additional axis control circuit 17 (step a4) to drive the motor 30a of the sealant supply pump. That is, when each axis of the robot is suddenly driven at the time of starting or stopping the driving of the robot, or when changing the moving speed, vibration or impact is generated. Acceleration / deceleration processing for gradually accelerating or decelerating the axis is performed, and the moving speed of the robot follows the moving speed Vr after this acceleration / deceleration processing. Therefore, if the speed command Vr after the acceleration / deceleration processing is read and the speed command Vc obtained by multiplying the speed Vr and the speed control proportional gain k2 is used to drive the motor 30a of the sealant supply pump, the seal gun 30b is driven.
The amount of the sealant supplied from the rod-shaped nozzle at a unit distance on the object is a constant value with respect to the speed control proportional gain k2 regardless of the moving speed Vr of the seal gun 30b, and even if the moving speed Vr changes. Speed control proportional gain k
The sealing work can be performed with a predetermined bead thickness corresponding to 2.

For example, if the seal gun 30b is currently moving on the sealing execution section P2-P3,
At this time, the speed control proportional gain k2 read from the speed control proportional gain storage register of the RAM 13 is the teaching position P.
A value corresponding to 2, that is, the sealing execution section P2
-A value corresponding to the bead thickness specified for P3. At the teaching position P2 when the sealing non-execution section P1-P2 shifts to the sealing execution section P2-P3, the nozzle shutter is suddenly opened, so that the current pressure Pn of the sealant falls, but it corresponds to the teaching position P1. Since the target pressure Ps set by the above is the initial dynamic pressure at the teaching position P2 in consideration of such pressure drop as well, the bead film thickness is reduced at the sealing start position P2 in the sealing execution section, or the excessive pressure is generated. Pressurization does not increase the bead thickness.

Hereinafter, while the flag F is "1", the processor 11 repeats the processing of step a1, step a5 and step a4 in each cycle to control the rotational speed of the motor 30a of the sealant supply pump to control the speed. Proportional gain k2
The sealing work is performed with a predetermined bead thickness determined by the value of.

When the sealing stop command is read from the teaching program, the shutter nozzle is closed and the seal gun 30b enters the sealing non-execution section. At this time, as a result of the flag F being set to "0", the processor 11 restarts the processing of steps a1 to a4 in the same manner as above. Hereinafter, the processor 11 performs steps a1 to a1 until the execution of the teaching program is completed.
Process related to pressure control in step a4 and step a1,
The processing relating to speed control in steps a5 and a4 is alternately performed based on the value of the flag F, and in the sealing execution section, the sealing work is performed with the bead film thickness specified by the speed control proportional gain k2 for each sealing execution section. At the same time, in the sealing non-execution section, pressure control is performed to obtain the initial dynamic pressure required at the start position of the next sealing execution section based on the target pressure value Ps for each sealing non-execution section.

As a result, the bead film thickness in each sealing execution section is stable, including the vicinity of the sealing start position in each section, and for example, an accurate bead shape as shown in FIG. 4 can be obtained. .

FIG. 3 shows a robot controller 10 when a spray type seal gun is used as the seal gun.
11 is a flowchart of a process executed by the processor 11 of FIG.

In this case, in the teaching program, the target value of the sealing agent pressure control corresponding to the section of the teaching position is programmed corresponding to each teaching position, and the target pressure value is the current value of the robot. Every time the position reaches each teaching position, the target value storage register Ps in the RAM 13 is sequentially updated and stored.

FIG. 5 is a conceptual diagram showing an example of the correspondence between the teaching position of the moving route and the sealing execution section. In this example, the teaching position section Q2-Q3, Q4-Q4'-Q.
5 is the sealing execution section, and teaching position section Q1-Q
2, Q3 to Q4 are non-sealing sections for positioning movement. The target values of the sealing agent pressure control corresponding to the bead widths of the non-sealing sections Q1-Q2 and Q3-Q4 are programmed corresponding to the teaching positions Q1 and Q3, respectively, and the sealing execution sections Q2-Q3, Q
The target values of the sealant pressure control corresponding to the bead widths of 4-Q4 'and Q4'-Q5 are programmed corresponding to the teaching positions Q2, Q4 and Q4', respectively. The pressure control target value in each sealing execution section is determined according to the desired bead width, and the pressure control target value in each sealing non-execution section corresponds to the initial pressure required in the next sealing execution section. It can be decided. Figure 5
Since the bead widths of the sealing execution sections Q2-Q3 and Q4-Q4 'are the same, the teaching position Q2
The target value programmed corresponding to the teaching position Q4 is the same value, for example, Ps (c). Therefore, the sealing execution sections Q2-Q3 and Q4-Q4 '
Initial pressures required at the sealing start positions Q2 and Q4 are equal, and as a result, the pressure control target value set corresponding to the teaching position Q1 and the pressure control target value set corresponding to the teaching position Q3 are The value is, for example, Ps
Equal with (a). On the other hand, the bead width in the sealing execution section Q4'-Q5 is the sealing execution section Q.
Since the bead width at 2-Q3 and Q4-Q4 'is made wider, the pressure control target value set corresponding to the teaching position Q4', for example, Ps (b), is
It is larger than the target value Ps (c) which is programmed corresponding to the teaching positions Q2 and Q4.

As described above, when changing the bead width within the sealing execution section, since the nozzle shutter is not closed when the bead width is changed, pressurization or depressurization with the supply of the sealant stopped. Operation is naturally impossible. Therefore, when changing the bead width within the sealing section, the initial dynamic pressure required for the changed bead width is not taken into consideration, and the bead width is changed according to the taught position that is the bead width switching position. Directly program the changed pressure control target value. For example, the initial dynamic pressure required at the sealing start position Q4 'of the sealing execution section Q4'-Q5 is ignored, and the teaching target position Q4' has a pressure target value Ps corresponding to the bead width of the sealing execution section Q4'-Q5. (B) is set as it is.

When the operation start command is input, the processor 11 sequentially reads the teaching program block by block at predetermined intervals, and the robot body 20 is read through the axis control circuit 16.
The servomotor for each axis is driven to drive the robot to move the seal gun along the teaching path, and, as described above, each time the current position of the seal gun 30b reaches each teaching position, a target value is set. RAM of the pressure values
It will be updated and stored in the target value storage register Ps in 13. When the sealing start command is read from the teaching program, the solenoid valve of the seal gun 30b is operated to open the nozzle shutter, and when the sealing end command is read, the solenoid valve is deactivated and the nozzle shutter is closed. Further, the processor 11 executes the process of FIG. 3 at a predetermined cycle (for example, a cycle synchronized with a distribution cycle for distributing a movement command to each axis of the robot).

The processor 11 first detects the pressure sensor 40.
The current pressure Pn of the sealant is read from (step b
1), the detected pressure Pn is subtracted from the target pressure value Ps of the sealing execution section or the sealing non-execution section stored in the target value storage register of the RAM 13, and the set proportional gain k1 for pressure control is added to this value. The speed command Vc of the motor 30a of the sealant supply pump is obtained by multiplying (step b2), and the speed command Vc is added to the additional axis control circuit 1
7 (step b3) to drive the motor 30a of the sealant supply pump.

For example, the seal gun 30b is currently shown in FIG.
If it is moving on the sealing non-execution section Q1-Q2, the target pressure read from the target value storage register of the RAM 13 is the value corresponding to the teaching position Q1, that is, the teaching position that is the start position of the next sealing execution section. This is the value of the initial dynamic pressure Ps (a) required at the position Q2.

The processor 11 carries out step b every predetermined period.
The process from 1 to step b3 is repeatedly executed, and at least until the seal gun 30b reaches the taught position Q2, the current pressure Pn of the sealant is made to match the target value Ps (a).

When the seal gun 30b reaches the next teaching position and the sealing start command is read from the teaching program, the solenoid valve is actuated to open the nozzle shutter and the movement path of the seal gun 30b is the sealing execution section Q2. -Entering Q3, the value of the target value storage register of the RAM 13 is rewritten to the value corresponding to the teaching position Q2, that is, the pressure value Ps (c) corresponding to the bead width in the sealing execution section Q2-Q3.

Teaching position Q2 when shifting from the non-sealing section Q1-Q2 to the sealing execution section Q2-Q3
In this case, since the nozzle shutter is suddenly opened, the current pressure Pn of the sealant drops, but the target pressure Ps (a) set corresponding to the teaching position Q1 is the teaching position in consideration of such pressure drop. Since it is the initial dynamic pressure at Q2, the bead width does not decrease due to an inadvertent pressure drop at the sealing start position Q2 in the sealing execution section. Hereinafter, the processor 11 repeatedly executes the same processing as described above every predetermined period based on the rewritten target value Ps (c) to set the current pressure Pn of the sealant to the target pressure Pn.
The sealing agent is stably held at s (c), and the sealing agent is jetted with a bead width corresponding to the target pressure Ps (c).

Further, the seal gun 30b moves to the next teaching position Q.
3 is reached and the sealing stop command is read from the teaching program, the nozzle shutter is closed and the movement path of the seal gun 30b is the sealing non-execution section Q3-Q4.
Then, the value of the target value storage register of the RAM 13 becomes the value corresponding to the teaching position Q3, that is, the value Ps (a) of the initial pressure required at the teaching position Q4 in the next sealing execution section Q4-Q4 '. Will be rewritten again. The phenomenon occurring in the sealing non-execution section Q3-Q4 is the same as in the case of the sealing non-execution section Q1-Q2 described above.

Further, when the seal gun 30b reaches the next teaching position Q4 and the sealing start command is read from the teaching program, the solenoid valve is actuated to open the nozzle shutter, and the movement path of the seal gun 30b is sealed. After entering the execution section Q4-Q4 ', the value of the target value storage register of the RAM 13 becomes the value corresponding to the teaching position Q4, that is, the pressure value Ps (c) corresponding to the bead width in the sealing execution section Q4-Q4'. Can be rewritten. The phenomenon occurring in the sealing execution section Q4-Q4 'is the same as in the case of the sealing execution section Q2-Q3 described above.

Next, when the seal gun 30b reaches the next teaching position Q4 'and the movement path of the seal gun 30b enters the sealing execution section Q4'-Q5, the value of the target value storage register of the RAM 13 reaches the teaching position Q4'. The corresponding value,
That is, the pressure value Ps (b) corresponding to the bead width in the sealing execution section Q4'-Q5 is rewritten.

When updating the target pressure value within the sealing execution section, the nozzle shutter is kept open and only the target pressure value is rewritten, and it is required at the start position of the next sealing execution section. Since the initial dynamic pressure is not applied in advance, the current pressure Pn is changed from the pressure value Ps (c) corresponding to the bead width in the sealing execution section Q4-Q4 'to the sealing execution section Q4'-Q5 with a primary delay. The pressure value Ps (b) corresponding to the bead width gradually changes. In other words, since the opening operation of the nozzle shutter does not participate in this switching, for example, the teaching position Q
There is no worrisome pressure drop at 2, Q4, etc., and as described above, the current pressure Pn is accompanied by a primary delay and the pressure value Ps (corresponding to the bead width in the sealing execution section Q4-Q4 '). From c) to the sealing execution section Q
Pressure value Ps corresponding to the bead width at 4'-Q5
It gradually changes to (b), and its bead width is, for example, as shown in FIG.
When the current pressure Pn reaches the pressure value Ps (b) corresponding to the bead width in the sealing execution section Q4'-Q5, the bead width in the sealing execution section Q4'-Q5 is also increased. Stabilize.

Thereafter, the processor 11 executes steps b1 to b until the execution of the teaching program is completed.
The process related to the pressure control of 3 is repeatedly performed every predetermined period, and in the sealing non-execution section, the initial pressure required at the start position of the next sealing execution section based on the target pressure value of each sealing non-execution section. While performing the pressure control to obtain the desired bead width, the bead width of each sealing execution period is stably maintained on the basis of the target pressure value for obtaining the desired bead width. Further, when the target pressure value is changed within the sealing execution section, the bead width is smoothly changed and the next sealing execution section having a different bead width is performed.

As a result, when the sealing non-execution section shifts to the sealing execution section, the width of the bead in each sealing execution section is stable, including the vicinity of the sealing start position in each section. 5
You can get the exact bead shape as shown in
Further, the bead width can be smoothly changed by changing the target pressure value within the continuous sealing execution section.

[0041]

The method for controlling the flow rate of the sealant according to the present invention stabilizes the bead film thickness during sealing by controlling the rotation speed of the motor of the sealant supply pump for the seal gun having the rod-shaped nozzle. When the sealing is not executed waiting for the start of the sealing, the drive torque of the motor is feedback-controlled so that the pressure of the sealing agent becomes the set pressure, so that the pressure of the sealing agent is stabilized at the start of the sealing. This makes it possible to prevent fluctuations in the bead film thickness that occur at the start of sealing and to perform the sealing operation with a stable bead film thickness over the entire section of the path. Also, the proportional gain and target value used for speed control and pressure control are set in the teaching program in correspondence with the teaching position. The bead thickness can be set arbitrarily.

For a seal gun equipped with a spray nozzle, the set pressure of the sealant when the sealing is performed and the set pressure of the sealant when the sealing is not performed are set separately in the robot controller to control the pressure. Since this is done, it is possible to compensate for the pressure drop of the sealant that occurs at the start of sealing, and it is possible to obtain a stable bead width over the entire section including the start of sealing. Since the target value for pressure control is set in the teaching program corresponding to the teaching position, the width of the bead for each teaching position on the sealing path can be arbitrarily set by operating the teaching program. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a sealing robot and a robot controller that implement an embodiment of the present invention.

FIG. 2 is a flowchart showing a main part of a processing operation performed by the robot control apparatus of the embodiment with the stick gun of the rod-shaped nozzle attached.

FIG. 3 is a flowchart showing a main part of a processing operation performed by the robot control apparatus of the embodiment with a spray gun seal gun attached.

FIG. 4 is a conceptual diagram showing an example of a correspondence relationship between a teaching position of a movement path regarding a rod-shaped nozzle and a sealing execution section.

FIG. 5 is a conceptual diagram showing an example of a correspondence relationship between a teaching position of a movement path regarding a spray nozzle and a sealing execution section.

FIG. 6 is a diagram showing a problem of a conventional control method regarding a seal gun having a rod-shaped nozzle.

FIG. 7 is a diagram showing a problem of a conventional control method regarding a seal gun having a spray nozzle.

[Explanation of symbols]

 10 Robot Control Device 11 Processor (CPU) 12 ROM 13 RAM 14 Nonvolatile Memory 15 Teaching Operation Panel 16 Axis Control Circuit 17 Additional Axis Control Circuit 18 I / O Interface 20 Robot Main Body 30a Sealant Supply Pump Motor 30b Seal Gun 40 Pressure Sensor

Claims (4)

[Claims] 1. In a control method in which a seal gun for applying a sealant with a rod-shaped nozzle is attached to a robot wrist and a sealant is applied by a robot, a sealant supply pump is connected to an additional axis control circuit of a robot controller to perform sealing. At the time of execution, the robot controller controls the rotation speed of the motor of the sealant supply pump by a speed command obtained by multiplying the moving speed of the robot by a predetermined proportional gain, and supplies the sealant to the seal gun attached to the robot. When the sealing is not executed, the pressure of the sealant is detected by the pressure sensor provided in the seal gun, and the drive torque of the motor is feedback-controlled so that the detected pressure becomes a set pressure. Method. 2. The method for controlling the flow rate of a sealant in a sealing robot according to claim 1, wherein the predetermined proportional gain and the set pressure of the sealant are set in a teaching program in correspondence with a robot teaching position in a sealing operation. . 3. In a control method in which a seal gun for applying a seal agent with a spray nozzle is attached to a robot wrist and a seal agent is applied by a robot, a robot is a seal agent supply pump for supplying the seal agent to the seal gun attached to the robot. In addition to being connected to the additional axis control circuit of the control device, at least the set pressure of the sealant when the sealing is executed and the set pressure of the sealant when the sealing is not executed are set in the robot controller and set in the seal gun. A method for controlling the flow rate of a sealant in a sealing robot, in which the pressure of the sealant is sequentially detected by a pressure sensor, and the driving torque of the motor of the sealant supply pump is feedback-controlled so that the detected pressure becomes the set pressure. . 4. The method for controlling the flow rate of the sealant in a sealing robot according to claim 3, wherein the set pressure of the sealant is set in the teaching program in correspondence with the robot teaching position in the sealing operation.