JPH11169762A - Coating robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten an instructing work time while enhancing coating quality without being affected by the skillfulness of an instructor. SOLUTION: The coating robot is provided with a coating gun 10 attached to the wrist unit 9 of an articlated manipulator 1, a coating material flow rate regulator 15 controlling the discharge flow rate of the coating material from the coating gun 10 and a controller 11 for controlling respective apparatus parts and the controller 11 applies correction to the discharge flow rate corresponding to the posture of the coating gun 10 so that the thickness of the coating film on the surface 2a of an article 2 to be coated becomes constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a painting robot used for painting an object to be painted, for example.

[0002]

2. Description of the Related Art Conventionally, in a teaching playback type coating robot, a coating gun is mounted on the tip of an articulated manipulator to discharge the coating onto a surface to be coated. Work is taking place. Further, the coating robot teaches in advance the discharge flow rate of the coating material from the coating gun in order to make the coating film thickness uniform. In this case, when the direction of the coating gun is downward, the discharge flow rate is small, when it is upward, the discharge flow rate is large, and when the direction of the coating gun is oblique to the surface to be coated, the discharge flow rate is increased. Taught. Further, as a method of making the coating film thickness uniform, a method of controlling the discharge flow rate according to a change in the moving speed of the coating gun is used.

[0003]

However, in a conventional painting robot which preliminarily teaches the discharge flow rate of the paint, it is necessary to give a detailed instruction for each painting path which is a moving path of the painting gun, so that it is inconvenient to use. In addition, there is a disadvantage that the teaching operation requires a long time. Further, in the above-mentioned coating robot, there is a problem that the coating quality varies depending on the teacher because the teaching content of the discharge flow rate differs between the teachers. Furthermore, in the above-mentioned painting robot, since the teaching operation requires skill, there is also a problem that a teaching error is likely to occur particularly when a beginner performs the teaching operation. In addition, in a painting robot that controls the discharge rate of paint in accordance with the moving speed of the paint gun, since the direction of the paint gun is not considered, for example, the direction of the paint gun is upward and with respect to the surface to be painted. The film thickness on the painted surface when slanted is thinner than the film thickness on the painted surface when the direction of the paint gun is downward, and as a result, the film thickness on the surface to be painted becomes uneven. There was a problem that would.

The present invention has been made under such a background, and a coating robot capable of shortening the teaching work time and improving the coating quality without being influenced by the skill of the teacher. The purpose is to provide.

[0005]

According to a first aspect of the present invention, there is provided a coating robot for coating an object to be coated with a coating gun attached to a tip of a manipulator. Discharge flow rate control means for controlling a discharge flow rate; attitude information calculating means for obtaining attitude information relating to the attitude of the coating gun; and the discharge flow rate and the coating gun in which the coating film thickness is constant on the coating surface of the workpiece. Storage means for storing a function representing a relationship with the attitude, and discharge flow rate correction means for correcting the discharge flow rate using the calculation result of the attitude information calculation means and the function. And According to the first aspect of the present invention, the discharge flow rate is corrected by the discharge flow rate correction means in accordance with the position of the coating gun so that the coating film thickness is constant on the coating surface of the object to be coated. As a result, the teaching operation time can be shortened and the coating quality can be improved without being influenced by the skill of the teacher. According to a second aspect of the present invention, there is provided a coating robot which performs coating on an object to be coated by a coating gun attached to a tip of a manipulator, wherein a discharge flow rate of the paint discharged from the coating gun is controlled. Control means, attitude information calculating means for obtaining attitude information on the attitude of the coating gun, and a database representing the relationship between the discharge flow rate and the attitude of the coating gun at which the coating film thickness is constant on the coating surface of the workpiece. And a discharge flow rate correcting means for correcting the discharge flow rate using the calculation result of the attitude information calculating means and the database. According to the second aspect of the invention, since the discharge flow rate is corrected using the database, the coating quality can be further improved by increasing the amount of the database.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an external configuration of a painting robot according to the first embodiment of the present invention. In this drawing, reference numeral 1 denotes a multi-joint type manipulator, which applies a coating to an object 2 to be coated. In the manipulator 1, reference numeral 3 denotes a base installed on a floor (not shown) of a factory. Here, a base coordinate system ΣB fixed to the base 3 is defined. In this base coordinate system ΣB, x
b is a unit vector in the x-axis direction, yb is a unit vector in the y-axis direction, and zb is a unit vector in the z-axis direction.

Reference numeral 4 denotes a rotating member rotatably mounted on the base 3, which is driven in the direction of the arrow θ1 shown in FIG. Reference numeral 5 denotes a first drive unit provided between the rotating member 4 and the first arm 6, and drives the first arm 6 in the direction of the arrow θ2 shown in FIG.

[0008] Reference numeral 7 denotes a second drive unit mounted between the first arm 6 and the second arm 8;
Is driven in the direction of arrow θ3 shown in FIG. 9
Is a wrist unit attached to the tip 8a of the second arm 8, and moves with three degrees of freedom. Reference numeral 10 denotes a coating gun attached to the tip of the wrist unit 9,
The mist-shaped paint T is discharged in a substantially flat conical shape onto the surface 2a to be coated of the object 2 shown in FIG. The paint adhered surface Ts on which the paint T adheres to the painted surface 2a is elliptical.

Here, a wrist coordinate system Δh fixed to the tip of the coating gun 10 is defined. The posture of the wrist coordinate system Δh changes following the posture of the coating gun 10. That is, the posture of the wrist coordinate system Σh changes relatively to the fixed base coordinate system ΣB. In this coordinate system Δh, xh is a unit vector in the x-axis direction, and the direction of the unit vector xh is the same as the direction in which the paint T is discharged from the paint gun 10. That is, the unit vector xh indicates the direction in which the paint T is discharged. yh is a unit vector in the y-axis direction, and the direction of the unit vector yh
s is the same as the short axis JS direction. zh is a unit vector in the z-axis direction, and the direction of the unit vector zh is the same as the direction of the major axis JL of the paint adhesion surface Ts. Further, since the above-described unit vectors xh, yh, and zh change over time following the attitude of the coating gun 10, the unit vectors xh (t), yh (t), and zh (t) are expressed as a function of time. Can be represented.

Further, in FIG. 2, distance l, gravitational acceleration vector g, velocity vector v (t), angle α, angle β
And the angle γ are defined. The distance l is expressed in the wrist coordinate system Σ
This is the distance in the x-axis direction from the origin of h to the surface to be coated 2a. The gravitational acceleration vector g is a vector representing the magnitude and direction of the gravitational acceleration. Velocity vector v (t)
Is a vector representing the speed in the moving direction of the coating gun 10, and is a vector representing the speed at the target point P where the x-axis and the surface 2a to be coated intersect. .

The angle α is the angle between the gravitational acceleration vector g and the unit vector xh. In other words, the angle α
Is the angle between the gravitational acceleration vector g and the paint T discharge direction. Is the angle between the unit vector xh and the velocity vector v (t). In other words, the angle β
Is the angle between the discharge direction of the paint T and the velocity vector v (t). The angle γ is an angle between the unit vector zh and the velocity vector v (t). In other words, the angle γ
Is the major axis JL of the paint adhesion surface Ts and the velocity vector v (t).
And the angle between them.

1 is a controller connected to the manipulator 1 via a cable 12, and controls the operation of the manipulator 1 and controls the discharge flow rate of the paint discharged from the coating gun 10. This controller 11
Will be described in detail. Reference numeral 13 denotes a paint supply device that supplies paint to the coating gun 10 via a hose 14. Reference numeral 15 denotes a paint flow controller which is attached to the second arm 8 and inserted in the middle of the hose 14, and under the control of the controller 11, the flow rate of the paint to be supplied to the coating gun 10, in other words, the coating gun. The discharge flow rate of the paint from 10 is adjusted.

FIG. 3 is a block diagram showing the electrical configuration of the painting robot according to one embodiment of the present invention. In this figure, parts corresponding to respective parts in FIG. 1 are denoted by the same reference numerals. In the controller 11 shown in FIG. 3, reference numeral 16 denotes a control unit for controlling the driving of the manipulator 1 and controlling the discharge flow rate of the paint discharged from the coating gun 10. The operation of the control unit 16 will be described later in detail. Reference numeral 17 denotes a coating program storage unit that stores a coating program executed by the control unit 16. Here, the coating program includes data relating to the position and posture of the coating gun 10 (hereinafter, referred to as position / posture data Di), operation control of the coating gun 10, and data relating to the discharge flow rate of the paint (hereinafter referred to as coating data Dt and Dt). ) Is generated.

Reference numeral 18 denotes a position input from the control unit 16.
From the attitude data Di, data of the target trajectory of the coating gun 10 at time t is generated. Here, the target trajectory is
It is represented by position vectors p (t) and R (t). This position vector p (t) is a vector representing the origin position of the wrist coordinate system Σh as viewed from the base coordinate system ΣB shown in FIG. 1 at time t. R (t) is a rotation matrix representing the posture of the wrist coordinate system Σh viewed from the base coordinate system ΣB at the time t, and is represented by a rotation matrix shown in the following equation (1). R (t) = [xh (t) yh (t) zh (t)] (1)

Reference numeral 19 denotes a manipulator drive control unit, based on the target trajectory data (position vector p (t), rotation matrix R (t)) input from the trajectory generation unit 18, and the position vector p (t). ) And rotation matrix R (t)
The drive of the manipulator 1 is controlled so as to obtain. 2
Reference numeral 0 denotes an operation signal generation unit that obtains a target value of the paint discharge flow rate at time t (hereinafter, referred to as a discharge flow target value q (t)) from the coating data Dt input from the control unit 16. Further, the operation signal generation unit 20 outputs the coating data Dt.
From the on / off signal d for turning on / off the coating gun 10
(T) is generated. When the on / off signal d (t) is off, the paint is not discharged from the coating gun 10, while when the on / off signal d (t) is on, the paint is discharged from the coating gun 10. .

A correction unit 21 corrects the discharge flow rate target value q (t) in accordance with the attitude of the coating gun 10 in order to make the coating film thickness of the paint adhered to the workpiece 2 constant. As the corrected discharge flow target value q ′ (t). Details of the operation of the discharge flow rate correction unit 21 will be described later. 22
Is a coating database unit that stores a function f (α, β, γ) used at the time of correction in the discharge flow rate correction unit 21. Details of the function f (α, β, γ) will be described later.

Reference numeral 23 denotes a discharge flow controller for controlling the paint flow controller 15 so that the paint discharge flow from the coating gun 10 becomes the corrected discharge flow target value q '(t). 24
Is an I / O control unit, and when the on / off signal d (t) is off, the paint gun 10 is turned off so that paint is not discharged from the paint gun 10. On the other hand, when the on / off signal d (t) is on, the I / O control unit 24 turns the coating gun 10 on so that the paint is discharged from the coating gun 10.

Next, the operation of the painting robot according to the above-described embodiment will be described with reference to FIG. FIG.
Is a P that explains the operation of the discharge flow rate correction unit 21 shown in FIG.
It is an AD diagram. Now, assuming that an operation start switch (not shown) is pressed, the control unit 16 shown in FIG. Then
The control unit 16 generates the position / posture data Di and the coating data Dt by executing the above-mentioned coating program, and then outputs these to the trajectory generating unit 18 and the operation signal generating unit 20, respectively.

Thus, the trajectory generating section 18 obtains the data (the position vector p (t) and the rotation matrix R) of the target trajectory of the coating gun 10 at the time t from the position / posture data Di.
(T)) is generated and output to the manipulator drive control unit 19 and the discharge flow rate correction unit 21, respectively.

As a result, the manipulator 1 controls the position vector p by the manipulator drive control unit 19.
(T) and the rotation matrix R (t) are controlled.

On the other hand, from the coating data Dt, the operation signal generator 20 calculates the target value q of the paint discharge flow rate at time t.
After obtaining (t), it is output to the discharge flow rate correction unit 21. Further, the operation signal generation unit 20 generates an on / off signal d (t) from the coating data Dt, and then outputs the on / off signal d / t.
Output to the O control unit 24. In this case, it is assumed that the on / off signal d (t) is on.

Then, the flow rate correction unit 21 proceeds to step S1 shown in FIG. 4, and inputs each data of the position vector p (t), the rotation matrix R (t), and the target value q (t) of the flow rate. Thereafter, the process proceeds to step S2.

In step S2, the discharge flow rate correction unit 21
Determines whether the time t is 0. Now, assuming that the time t is 0, the discharge flow rate correction unit 21 sets the determination result of step S2 to "YES" and proceeds to step S3. In step S3, the discharge flow rate correction unit 21 sets the correction coefficient η for the discharge flow rate target value q (0) to 1, and then proceeds to step S7.

In step S7, the discharge flow rate corrector 21
Are expressed as “1”, “q” as the correction coefficient η in the following equation (2).
(T) "as the discharge flow rate target value q (0) at time 0
To obtain the corrected discharge flow rate target value q ′ (0) at time 0, and then proceed to step S8. q ′ (t) = η · q (t) (2)

In step S8, the discharge flow rate corrector 21
Outputs the obtained data of the corrected discharge flow target value q ′ (0) to the discharge flow control unit 23, and returns to step S1 to repeat the above-described processing. Thereby, the conical paint T is discharged from the discharge port (not shown) of the coating gun 10 shown in FIG.

Then, in step S2 shown in FIG. 4, the discharge flow rate correction unit 21 determines again whether or not the time is zero. In this case, assuming that the time is t, the discharge flow rate correction unit 21 sets the determination result of step S2 to "NO" and proceeds to step S4. In step S4, the discharge flow rate correction unit 21 calculates the velocity vector v (t) at the target point P shown in FIG. 2 from the following equation (3), and then proceeds to step S5.
Proceed to. v (t) = ((p (t) + 1.xh (t) -p (t-1) -l.xh (t-1)) / Ts・ (3)

In the above equation (3), "p (t)" is a position vector p representing the origin position of the wrist coordinate system Σh as viewed from the base coordinate system ΣB at time t, and "l" is the distance l shown in FIG. “Xh (t)” is a unit vector shown in FIG. 2 at time t. “P (t−1)” is the time t−1
Is a position vector representing the origin position of the wrist coordinate system Σh viewed from the base coordinate system ΣB, and “xh (t−1)” is a unit vector shown in FIG.
Ts "is the time from time t-1 to time t. Here, the distance l in equation (3) is a function of the time t, but in this case, l (t) = l0 ( (Constant value), the constant value l0.

In step S5, the discharge flow rate corrector 21
Calculates the angle α, angle β, and angle γ shown in FIG. 2 representing the attitude of the coating gun 10 from the following equations (4) to (6), and then proceeds to step S6. α = cos ⁻¹ (xh (t) ^T · g) (4) β = cos ⁻¹ (xh (t) ^T · v (t) / | v (t ) |) (5) γ = cos ⁻¹ (zh (t) ^T・ v (t) / | v (t) |) (6)

In the above equations (4) to (6), "xh
(T) "is the unit vector x shown in FIG.
h, the subscript ^{T of} “xh (t) ^T ” is transposed, “g” is the gravitational acceleration vector g, “v (t)” is the velocity vector v (t), “zh (t)” obtained in step S4. "Is the unit vector zh shown in FIG. 2 at time t, and" zh (t)
The suffix ^{T of T} ″ represents transposition, respectively.

In step S6, the discharge flow rate corrector 21
Is a function f (α, β, γ) from the coating database unit 22.
Is read. Here, the function f (α, β,
γ) is a function of the angle α, the angle β, and the angle γ representing the attitude of the coating gun 10, and is a function for obtaining the correction coefficient η. The correction coefficient η is a coefficient that is multiplied by a standard paint flow rate qs for obtaining a standard coating thickness δ0 on the surface 2a of the workpiece 2 to be coated.

Next, the discharge flow rate correction unit 21 calculates the function f
After substituting the angles α, β, and γ obtained in step S5 into (α, β, γ) to obtain the correction coefficient η, the process proceeds to step S7.

In step S7, the discharge flow rate correction unit 21
Is calculated as the correction coefficient η in the above-described equation (2) in step S6.
And the discharge flow target value q (t) at time t as “q (t)”, respectively,
After the corrected discharge flow target value q ′ (t) at the time of is obtained, the process proceeds to step S8.

In step S8, the discharge flow rate correction unit 21
Outputs the obtained data of the corrected discharge flow target value q ′ (t) to the discharge flow controller 23, and returns to step S1 to repeat the above-described processing. As a result, the paint T having a discharge flow rate corresponding to the posture of the coating gun 10 is applied from the discharge port (not shown) of the coating gun 10 shown in FIG.
Injected toward. Therefore, according to the painting robot according to the above-described embodiment, the paint T
Is always the standard coating thickness δ0.

As described above, according to the painting robot according to the above-described embodiment, the paint T discharged from the painting gun 10 is changed according to the posture (angle α, angle β, and angle γ) of the painting gun 10. Since the discharge flow rate is controlled, the coating thickness on the surface to be coated 2a can be made constant. Further, according to the coating robot according to the above-described embodiment, the following effects can be obtained. (A) Since there is no need to give detailed instructions for each painting pass, which is a moving path of the painting gun, the usability can be improved and the teaching operation time can be shortened. (B) Since the teaching content of the discharge flow rate is constant regardless of the instructor, it is possible to always obtain high coating quality regardless of the instructor's skill level. (C) Even beginners can teach easily,
Teaching mistakes can be prevented.

Although one embodiment of the present invention has been described with reference to the drawings, the specific configuration is not limited to this, and even if there is a design change or the like without departing from the gist of the present invention. Included in the present invention. For example, in the above-described painting robot, an example in which the correction coefficient η is obtained using the function f (α, β, γ) has been described. However, the present invention is not limited to this, and the function f (α, β, γ) may be used. Alternatively, the relationship between the correction coefficient η and the angles α, β, and γ may be stored in a database, and the correction coefficient η may be obtained using this database. In this case, by increasing the amount of the database, the coating quality can be further improved as compared with the case where the function f (α, β, γ) is used.

[0036]

According to the first and second aspects of the present invention, the discharge flow rate is corrected by the discharge flow rate correction means in accordance with the position of the coating gun so that the coating film thickness is constant on the surface to be coated. Therefore, the effect is obtained that the teaching work time can be shortened and the coating quality can be improved without depending on the skill of the teacher. According to the second aspect of the present invention,
By increasing the amount of the database, there is an effect that the coating quality can be further improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external configuration of a painting robot according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a configuration near an object to be coated 2 and a coating gun 10 shown in FIG.

FIG. 3 is a block diagram showing an electrical configuration of a painting robot according to one embodiment of the present invention.

FIG. 4 is a PAD illustrating the operation of the discharge flow rate correction unit 21 shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Manipulator 2 Workpiece 2a Workpiece surface 9 Wrist unit 10 Painting gun 11 Controller 13 Paint supply device 15 Paint flow controller 16 Control unit 18 Trajectory generation unit 19 Manipulator drive control unit 20 Operation signal generation unit 21 Discharge flow correction unit 22 Painting database unit 23 Discharge flow rate control unit

Claims (2)

[Claims] 1. A coating robot which performs coating on an object to be coated by a coating gun attached to a tip of a manipulator, wherein a discharge flow rate control means for controlling a discharge flow rate of the coating material discharged from the coating gun; Attitude information calculating means for obtaining attitude information relating to the attitude of the gun, and storage means for storing a function representing a relationship between the discharge flow rate and the attitude of the coating gun at which the coating film thickness is constant on the coating surface of the object to be coated. And a discharge flow rate correcting means for correcting the discharge flow rate using the calculation result of the attitude information calculating means and the function. 2. A coating robot for coating an object to be coated with a coating gun attached to a tip of a manipulator, comprising: a discharge flow rate control means for controlling a discharge flow rate of the coating material discharged from the coating gun; Attitude information calculation means for obtaining attitude information on the attitude of the gun, and storage means for storing a database representing a relationship between the discharge flow rate and the attitude of the coating gun at which the coating film thickness is constant on the coating surface of the workpiece. And a discharge flow rate correcting means for correcting the discharge flow rate using the calculation result of the attitude information calculating means and the database.