JP2023003216A - Control system of working robot - Google Patents

Abstract

To achieve modification teaching capable of suppressing the decrease in production speed.SOLUTION: A control system 10 includes a conveyance device 20 for conveying a working object 40 having a flat first plane 41 in a predetermined conveyance direction, a working robot 30 for jetting and spraying a spray material onto the working object, a plurality of distance sensors 51, 52 and 53 provided on a conveyance direction upstream of the working robot 30, and a control part 70 for controlling the working robot 30, wherein the control part 70 calculates inclination θ of the first plane 41 on the basis of detection results of the first distance sensor 51 and the second distance sensor 52, modifies teaching data for regulating operation of the working robot on the basis of the calculated inclination θ, and controls the working robot 30 on the basis of the modified teaching data.SELECTED DRAWING: Figure 1

Description

The present technology relates to a control system for a working robot.

2. Description of the Related Art Conventionally, there has been known a painting robot that sprays paint onto a conveyed work object. The vehicle painting robot described in Patent Document 1 is taught scanning path data for a bell that performs a painting operation in correspondence with design data for the shape of the vehicle body at a predetermined transport position. Then, in order to correct the error caused by the shape deviation of the vehicle body at the actual transport position, correction teaching is performed using the detection result of the distance sensor attached near the bell (correcting the scanning path data). is disclosed.

JP 2009-20846 A

The distance sensor described in Patent Literature 1 is attached to the tip of a robot arm of a vehicle painting robot, and there is a problem that it takes time to align the sensor. More specifically, the distance sensor is first automatically moved to the scanning reference point for correction by operating the teaching box, and then finely adjusted by visual observation from the scanning reference point for correction so as to approach the reference portion to be coated. After that, by controlling the height of the coating robot, it is aligned with the position facing the distance sensor. The distance sensor is designed to detect the shape deviation of the vehicle body after such alignment. Therefore, if the correction teaching described in Patent Document 1 is performed, there is a concern that the production speed will be greatly reduced.

The technique described in the specification of the present application was perfected based on the above-described actual situation, and aims at realizing correction teaching capable of suppressing a decrease in production speed.

(1) A work robot control system according to the present technology includes a conveying device that conveys a work object having a flat first surface in a predetermined conveying direction, and a spray material that is sprayed onto the work object. a work robot; a plurality of distance sensors provided upstream of the work robot in the conveying direction; and a second distance sensor that detects a distance from a second measurement point on the first surface, wherein the control unit controls the first distance sensor and the calculating the inclination of the first surface based on the detection result of the second distance sensor, correcting the teaching data defining the operation of the working robot based on the calculated inclination, and correcting the teaching data based on the corrected teaching data to control the working robot;

According to the control system for the work robot described above, the control unit can calculate the inclination of the first surface of the work object to be conveyed based on the detection results of the first distance sensor and the second distance sensor. The control unit corrects the teaching data based on this calculation result, and controls the work robot based on the corrected teaching data, thereby realizing corrected teaching. The teaching data is corrected according to the transport state of the work object to be transported (specifically, the inclination of the first surface). Here, the distance sensor is provided separately from the working robot (upstream in the transport direction from the working robot), and unlike the prior art described in Patent Document 1, alignment is not required for detection by the distance sensor. Further, since the distance sensor is provided upstream of the work robot in the transport direction, the detection work by the distance sensor and the work of spraying the spray material by the work robot can be performed in parallel. As a result, it is possible to suppress a decrease in production speed due to detection by the distance sensor. Furthermore, since the distance sensor does not need to be attached to the working robot, it is not limited to a dedicated product. By using a general-purpose product as the distance sensor, it is possible to suppress an increase in cost, prevent the overall control system from becoming complicated, and suppress an increase in the occurrence of failures.

(2) The shape and size of the work object are specified, and the plurality of distance sensors measure the distance to a second surface of the work object that extends in a direction intersecting the first surface. a third distance sensor for detecting, the control unit calculates the position of the work object based on the detection results of the first distance sensor, the second distance sensor, and the third distance sensor, The teaching data may be corrected based on the calculated position.

According to the control system for the working robot described above, since the shape and size of the work object are specified, the control unit uses this information, the first distance sensor, the second distance sensor, and the third distance sensor. The position of the work object can be calculated based on the detection result.

(3) The third distance sensor is capable of detecting passage of a most downstream portion or an most upstream portion of the work object in the conveying direction, and the control unit detects a result of detection by the third distance sensor. to calculate the start timing for injecting the spray material, and the teaching data may be corrected based on the calculated start timing.

According to the above control system for the work robot, the control unit can calculate the position of the forward end of the work object in the transport direction. This makes it possible to more accurately correct the start timing of spraying the spray material in the teaching data.

(4) The first distance sensor and the second distance sensor are provided at a position capable of facing the first surface of the work object to be conveyed, and the third distance sensor is arranged to face the work object to be conveyed. It may be provided at a position capable of facing the second surface of the object.

According to the control system for the work robot described above, the detection accuracy of each distance sensor can be improved.

(5) The conveying device is a conveyor including a rail that is a conveying route of the work object and a hanger that is connected to the rail and hangs the work object, and the plurality of distance sensors are: A support member may be provided through which the work object suspended by the hanger can pass.

According to the control system for the working robot described above, the work object can be easily conveyed by the overhead conveyor, and the distance sensor can be easily provided by the supporting member. On the other hand, when an overhead conveyor is used, the conveying state of the work object (the inclination of the first surface, etc.) tends to vary. become able to.

(6) The working robot includes a robot base placed on the floor, a robot arm connected to the robot base, and an end of the robot arm opposite to the robot base, and configured to perform the spraying. and an injection gun for injecting material, wherein the controller may control the robot base, the robot arm, and the injection gun based on the corrected teaching data.

According to the working robot control system described above, the working robot can be accurately controlled by controlling each part of the working robot based on the corrected teaching data.

According to the present technology, it is possible to realize correction teaching capable of suppressing a decrease in production speed.

1 is a perspective view schematically showing a control system for a painting robot according to Embodiment 1; FIG. Block diagram showing the electrical configuration of the coating robot control system Plan view of FIG. Another plan view of FIG. A plan view showing the amount of deviation from the basic conveying state of the object to be coated Plan view in which the main part of FIG. 5 is enlarged Another plan view showing the amount of deviation from the basic conveying state of the object to be coated FIG. 8 is a perspective view schematically showing a control system for a coating robot according to Embodiment 2;

<Embodiment 1>
A control system 10 (hereinafter simply referred to as the control system 10) of a painting robot 30 (an example of a work robot) according to Embodiment 1 will be described with reference to FIGS. 1 to 7. FIG. Parts of each drawing other than FIG. 2 show the X-axis, the Y-axis, and the Z-axis, and are drawn so that the direction of each axis is the same direction in each drawing. The X-axis direction is the left-right direction, the Y-axis direction is the front-back direction, and the Z-axis direction is the up-down direction.

The control system 10 causes the coating robot 30 to inject and spray paint (an example of a spraying material) onto the transported object 40 (an example of a work or work object), thereby automatically spraying the object 40. It is a system that paints effectively. As shown in FIG. 1, the control system 10 includes a conveyor 20 (an example of a conveying device) that conveys an object 40 to be coated, a coating robot 30 that sprays paint onto the conveyed object 40 to be coated, and a coating robot. A plurality of (three in this embodiment) distance sensors 51, 52, and 53 are provided at predetermined positions upstream of 30 in the transport direction.

As shown in FIG. 1, the coating robot 30 includes a robot base 31 placed on the floor, an articulated robot arm 33 connected to the robot base 31, and a tip of the robot arm 33 (the robot base 31). and a paint gun 35 (an example of an injection gun) that is attached to the end opposite to) and injects paint.

Further, as shown in FIG. 2, the control system 10 includes a control section 70 such as a CPU or a microcomputer, and a storage section 80 such as a memory such as a RAM or ROM. The storage unit 80 stores an operation control program for the coating robot 30, and the control unit 70 controls each unit (the robot base 31, the robot arm 33, and the coating gun 35) of the coating robot 30 based on the operation control program. do. The motion control program includes teaching data that defines the motion of the coating robot 30 (various setting data such as movement path, paint ejection start position, ejection stop position, ejection direction, etc.). Note that the storage unit 80 may be built in the control unit 70 .

The control unit 70 is electrically connected to the conveyor 20, the painting robot 30, the distance sensors 51, 52, 53, and the storage unit 80, as shown in FIG. The control unit 70 corrects the teaching data based on the detection results of the distance sensors 51, 52, 53, and controls the painting robot 30 based on the corrected teaching data, as will be described later in detail. Note that the conveyor 20 may be controlled by a control device separate from the control system (control section 70) of the painting robot 30. FIG.

As shown in FIGS. 1, 3, and 4, the conveyor 20 includes a rail 21 that is a conveying path, and a hanger 23 that is connected to the rail 21 and suspends the object 40 to be coated. The conveyor 20 is a so-called overhead conveyor that conveys the object 40 to be coated while suspended from a hanger 23 along a rail 21 arranged upward. The rails 21 are routed appropriately according to the work place, etc. In this embodiment, the rails 21 extend in the X-axis direction (horizontal direction, an example of the transport direction), and the object 40 to be coated extends in the +X-axis direction. Description will be given assuming that it is transported.

As shown in FIGS. 1, 3 and 4, the hanger 23 extends vertically as a whole, has an upper end (connecting portion) 23A connected to the rail 21, and has a lower portion engaged with the object 40 to be coated. It is a two-forked hook-shaped engaging portion 23B. The hanger 23 is manufactured by bending a metal pipe, for example, but the material, shape, etc. are not limited, and can be appropriately changed according to the object to be coated 40 to be conveyed. A plurality of hangers 23 are connected to the rail 21 at intervals, and an object 40 to be coated is suspended one by one from each hanger 23 and conveyed one after another.

As shown in FIGS. 1, 3 and 4, the object 40 has at least a flat first surface (eg, top surface 41) and a second surface (eg, rear surface 43) extending in a direction intersecting the first surface. ), and in this embodiment, a rectangular parallelepiped box having a front opening 45 will be described as an example. The object 40 to be coated is suspended by the hanger 23 by inserting the engaging portion 23B of the hanger 23 into the front opening 45 . In addition, the shape of the second surface of the object 40 to be coated is not limited to a flat shape, and may be, for example, an uneven shape or a curved shape. Specific examples of the object to be coated having a flat first surface and an uneven second surface include a transformer box 140 (see Embodiment 2 described later), a flat first surface and a second surface. A specific example of the curved object to be coated is a cylindrical container for a water bottle.

The connecting portion 23A of the hanger 23 is not excessively fixed to the rail 21 and is connected to the rail 21 in a manner having a certain degree of mobility. 23 A of connection parts are attached so that a worker can move along the extension direction (X-axis direction) of the rail 21 because a worker applies force. As a result, the worker can easily hang the article 40 to be coated from the hanger 23, and the work of hanging the article 40 to be coated can be speeded up and made efficient. Moreover, the hanger 23 is designed so that it can be commonly used for objects 40 to be coated having different sizes and shapes.

On the other hand, if the hanger 23 is provided in this way, the suspended state of the article 40 to be coated will vary to some extent. More specifically, as shown in FIGS. 3 and 4, the basic transport state of the suspended workpiece 40 is that the top surface 41 is parallel to the horizontal plane (XY plane) (condition 1), the top surface 41 is positioned vertically below the connection portion 23A of the hanger 23 (on the extension line L1 in the Z-axis direction) (Condition 2, in other words, the positions of the center 41A and the connection portion 23A in the X-axis direction and the Y-axis direction are the same).

For example, as shown in FIGS. 5 and 6, consider a state in which the engaging portion 23B of the hanger 23 is inserted into the front opening 45 of the object 40 to a small depth (insertion length). In this case, the top surface 41 is inclined downward toward the rear in the Y-axis direction. When viewed from the YZ plane direction, the top surface 41 is tilted from the horizontal plane by an inclination angle θ (an example of inclination) with respect to the basic transport state indicated by the two-dot chain line, and Condition 1 is not satisfied. In addition, the center 41A of the top surface 41 is displaced from the connecting portion 23A of the hanger 23 in the Y-axis direction by ΔY, and the condition 2 is not satisfied. Further, for example, as shown in FIG. 7, when the position where the hanger 23 is inserted into the front opening 45 shifts downstream in the conveying direction, the center 41A of the top surface 41 is ΔX in the X-axis direction from the connecting portion 23A of the hanger 23. , and condition 2 is not satisfied.

In general, the teaching data for the coating robot 30 is set assuming that the suspended workpiece 40 is in a predetermined state. In this embodiment, as shown in FIGS. 3 and 4, the teaching data are set assuming a basic conveying state in which the object 40 satisfies the conditions 1 and 2 above. For this reason, as shown in FIGS. 5 to 7, the object 40 to be coated is suspended with deviation from the basic transport state, and is transported to the coating robot 30 as it is. The spray start position, spray stop position, spray direction, and the like of the paint are not suitable for the object 40 to be actually conveyed, and coating defects (work defects) may occur. Therefore, based on the detection results of the distance sensors 51, 52, and 53, the control unit 70 of the control system 10 according to the present embodiment determines the amount of deviation (each amount of deviation θ, ΔY, ΔX) are calculated, and the teaching data is corrected based on the calculated deviation.

The teaching data have different values depending not only on the hanging state of the object 40 to be coated, but also on the shape and size of the object 40 to be coated. In this embodiment, it is assumed that the shape and size of the object to be coated 40 to be conveyed are specified in advance, and the teaching data corresponding thereto are set. However, the shape and size of the object 40 to be coated are not specified in advance, and may be specified by reading an identification information tag attached to the object 40 to be coated, for example.

As shown in FIGS. 1 and 3, the distance sensors 51, 52, 53 are fixed to a frame 55 (an example of a support member) erected on the floor upstream of the coating robot 30 in the conveying direction. The frame 55 is formed in a frame shape so that the object 40 to be coated can pass through the inside while being suspended on the hanger 23. However, if the distance sensors 51, 52, 53 can be fixed, the frame 55 may be shaped like a frame. etc. is not limited. As shown in FIG. 3, the frame 55 according to the present embodiment includes a rod-shaped first frame 55A extending in the Y-axis direction perpendicularly to the rail 21 directly above the rail 21, and a first frame 55A extending in the Z-axis direction. and a rod-shaped second frame 55B. The first distance sensor 51 and the second distance sensor 52 are fixed side by side on the first frame 55A with a predetermined interval Y1, and can face the top surface 41 of the object 40 to be conveyed. . The third distance sensor 53 is fixed to the second frame 55B and can face the rear surface 43 of the object 40 to be conveyed.

Each of the distance sensors 51, 52, 53 includes a light-emitting portion that emits laser light and a light-receiving portion that receives the laser light reflected by the surface (top surface 41 or rear surface 43) of the object 40 to be coated. Each of the distance sensors 51, 52, 53 detects the object to be coated from each distance sensor 51, 52, 53 based on the time it takes for the laser light emitted from the light emitting part to travel straight, return to the light receiving part due to reflection, and be received. Measure the distance to the 40 surface. As shown in FIG. 6, the first distance sensor 51 and the second distance sensor 52 emit laser beams in the -Z-axis direction, and the distance from the first measurement point 41B on the top surface 41 hit by the straight laser beams is calculated. Z1 and the distance Z2 from the second measurement point 41C are measured. The third distance sensor 53 emits a laser beam in the -Y-axis direction and measures a distance Y3 from a third measuring point 43B on the rear surface 43 which is hit by the straight laser beam.

The control unit 70 calculates the inclination angle θ of the top surface 41 of the object 40 with respect to the horizontal plane (XY plane) based on the detection results (distances Z1 and Z2) of the first distance sensor 51 and the second distance sensor 52. do. The tilt angle θ is expressed by the following equation as shown in FIG.
tan(θ)=(Z2−Z1)/Y1
θ=tan ⁻¹ {(Z2−Z1)/Y1}

In addition, the control unit 70 determines the amount of deviation in the Y-axis direction based on the tilt angle θ, the detection result (distance Y3) of the third distance sensor 53, and the previously specified shape and size of the object 40 to be coated. ΔY is calculated. Furthermore, by continuously detecting the detection result (distance Y3) of the third distance sensor 53, the change in the detection result is the most downstream or most upstream portion in the conveying direction of the object 40 to be coated (in this embodiment, as shown in FIG. 6). As shown, passage of the most downstream portion 43B1 or the most upstream portion 43B2) of the back surface 43 can be detected. As a result, the control unit 70 can calculate the displacement amount ΔX in the Y-axis direction, calculate the position of the forward end of the work object in the transport direction, and calculate the timing at which the paint gun 35 starts spraying the paint.

The control unit 70 corrects the teaching data based on the calculated deviation amounts (θ, ΔY, ΔX), and controls the coating robot 30 based on the corrected teaching data. Specifically, the angle of the reference point of the robot base 31 of the painting robot 30 with respect to the floor (horizontal plane) is corrected, and the positional relationship with the center 41A of the top surface 41 is corrected in the Y-axis direction and the Z-axis direction. Also, the start timing (and thus the end timing) of spraying paint by the paint gun 35 is corrected.

The control unit 70 controls the coating robot 30 without correcting the teaching data when the calculated deviation amounts θ, ΔY, and ΔX are all zero. Further, when each of the calculated deviation amounts θ, ΔY, and ΔX exceeds the correction allowable upper limit values θmax, ΔYmax, and ΔXmax set in advance for each, the control unit 70 determines that the correction possible range is exceeded. It is also possible to adopt a mechanism for judging and warning an error or the like.

According to the control system 10 described above, based on the detection results of the distance sensors 51, 52, and 53, the control unit 70 determines the amount of deviation of the workpiece 40 to be transported from the basic transport state (each amount of deviation θ, ΔY , ΔX) can be calculated. Then, the control unit 70 corrects the teaching data based on this calculation result, and controls the work robot based on the corrected teaching data, thereby realizing corrected teaching. The spray start position, spray stop position, spray direction, etc. of the coating robot 30 included in the teaching data are corrected based on the detection result of the transport state (hanging state) of the actually transported object 40. Therefore, defective coating (defective work) is suppressed, and the object 40 to be coated can be preferably coated.

Also, in the control system 10, the distance sensors 51, 52, 53 are fixed to the frame 55 instead of the painting robot 30. As shown in FIG. Since the distance sensors 51, 52, 53 are provided separately from the coating robot 30, there is no need to align the distance sensors 51, 52, 53 as in the prior art described in Patent Document 1, and the adjustment associated with the alignment is eliminated. A decrease in production speed can be suppressed. Further, since the distance sensors 51 , 52 , 53 are provided upstream of the coating robot 30 in the conveying direction, the work of detecting the conveying state of the object 40 to be coated by the distance sensors 51 , 52 , 53 and the paint , can proceed simultaneously in parallel. As a result, a decrease in production speed can be further suppressed. Furthermore, since the distance sensors 51, 52, 53 do not need to be attached to the coating robot 30, they are not limited to exclusive products. By using general-purpose products for the distance sensors 51, 52, 53, it is possible to suppress high costs, prevent the control system 10 as a whole from becoming complicated, and suppress an increase in the occurrence of failures.

<Embodiment 2>
A control system 110 according to Embodiment 2 will be described with reference to FIG. The control system 110 differs from the first embodiment in the configuration of the hanger 123 of the conveyor 120 and the mounting positions of the first distance sensor 51 and the second distance sensor 52 . In the second embodiment, overlapping descriptions of the same configurations, functions and effects as those of the first embodiment will be omitted.

As shown in FIG. 8, the conveyor 120 suspends and conveys the object 140 to be coated by engaging the four corners of the object 140 to be coated with the engaging portions 123B of the hanger 123 . The object 140 to be coated is a transformer box having a flat bottom surface 142 (another example of a first surface), uneven side surfaces including a back surface 143, and an upward opening.

The first distance sensor 51 and the second distance sensor 52 are fixed to a third frame 55C that extends in the Y-axis direction in a rod shape from the frame 55 and that is below the conveyed object 140 to be coated. Thereby, each of the distance sensors 51 and 52 can face the bottom surface 142 of the object 140 to be coated. Each of the distance sensors 51 and 52 emits laser light in the +Z-axis direction, and measures the distances to the first and second measurement points on the bottom surface 142 on which the straight laser light hits, respectively.

<Other embodiments>
The present technology is not limited to the embodiments described by the above description and drawings, and the following embodiments are also included in the technical scope of the present technology.

(1) The material to be sprayed may be a lubricant, a sealing material, or the like other than paint, and the type thereof is not limited. Further, the spraying material is not limited in its state as long as it can be sprayed, such as liquid, powder, or a mixture thereof. For example, when the spray material is paint, liquid paint or powder paint can be used.

(2) The conveying device is not limited to the overhead conveyors 20 and 120, and may be configured to support and convey the article 40 to be coated from below or from the side, for example.

(3) The mounting location of the control unit 70 and the storage unit 80 is not limited, and for example, they may be built in the painting robot 30, or they may be built in other computers or external servers.

DESCRIPTION OF SYMBOLS 10,110... Control system, 20,120... Conveyor (an example of a conveying apparatus), 21... Rail, 23,123... Hanger, 30... Painting robot (an example of a working robot), 31... Robot base, 33... Robot arm, 35... Coating gun (example of spray gun), 40... Object to be coated (example of work object), 41... Top surface (example of first surface), 43, 143... Back surface (example of second surface), 51 1st distance sensor 52 2nd distance sensor 53 3rd distance sensor 55 Frame (an example of support member) 70 Control section 142 Bottom (an example of first surface)

Claims (6)

a conveying device for conveying a work object having a flat first surface in a predetermined conveying direction;
a working robot that injects and sprays a spraying material onto the work object;
a plurality of distance sensors provided upstream of the work robot in the transport direction;
a control unit that controls the working robot,
The plurality of distance sensors are
a first distance sensor that detects a distance from a first measurement point on the first surface;
a second distance sensor that detects a distance to a second measurement point on the first surface;
The control unit
calculating the inclination of the first surface based on the detection results of the first distance sensor and the second distance sensor;
correcting teaching data that defines the operation of the working robot based on the calculated inclination;
A working robot control system that controls the working robot based on the corrected teaching data. The shape and size of the work object are specified,
The plurality of distance sensors further includes a third distance sensor that detects a distance from a second surface of the work object extending in a direction intersecting the first surface,
The control unit
calculating the position of the work object based on the detection results of the first distance sensor, the second distance sensor, and the third distance sensor;
2. The working robot control system according to claim 1, wherein said teaching data is corrected based on said calculated position. The third distance sensor is capable of detecting passage of a most downstream portion or an most upstream portion of the work object in the conveying direction,
The control unit
calculating a start timing for injecting the spray material based on the detection result of the third distance sensor;
3. The working robot control system according to claim 2, wherein said teaching data is corrected based on said calculated start timing. The first distance sensor and the second distance sensor are provided at a position capable of facing the first surface of the work object to be transported,
4. The working robot control system according to claim 2, wherein the third distance sensor is provided at a position capable of facing the second surface of the conveyed work object. The conveying device is
a rail that is a transport route for the work object;
a hanger connected to the rail for hanging the work object,
The control of the working robot according to any one of claims 1 to 4, wherein the plurality of distance sensors are provided on a support member through which the work object suspended on the hanger can pass. system. The working robot is
a robot base placed on the floor;
a robot arm connected to the robot base;
a spray gun attached to the end of the robot arm opposite to the robot base for spraying the spray material;
6. The working robot control system according to any one of claims 1 to 5, wherein the control unit controls the robot base, the robot arm, and the injection gun based on the corrected teaching data. .

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