WO2020012565A1

WO2020012565A1 - Robot control device

Info

Publication number: WO2020012565A1
Application number: PCT/JP2018/026078
Authority: WO
Inventors: 亮輔川西; 泰憲櫻本
Original assignee: 三菱電機株式会社
Priority date: 2018-07-10
Filing date: 2018-07-10
Publication date: 2020-01-16
Also published as: DE112018007703B4; CN112384340A; JPWO2020012565A1; JP6632783B1; DE112018007703C5; DE112018007703T5

Abstract

A robot control device (100) has: a storage unit (20) that stores a robot program (21) including teaching points; an interference avoidance processing unit (12) that performs interference avoidance processing when a robot (30) grasps a workpiece; a grasp correction acquisition unit (13) that acquires the grasp correction in the interference avoidance processing, said grasp correction being the amount of correction of a grasp position, which is a position in the workpiece grasped by the robot (30), and workpiece orientation; a teaching point acquisition unit (14) that acquires a teaching point; a teaching point revision unit (15) that revises the teaching point when the grasp position and workpiece orientation are changed because of the interference avoidance processing; and an operation command unit (16) that sends operation commands to the robot (30) in accordance with the robot program (21) in which the teaching point has been revised.

Description

Robot controller

The present invention relates to a robot control device that operates a robot based on a robot program.

When recognizing a randomly arranged work by image processing and gripping it with a robot, if the robot is operated to grip the position of the work as taught in the posture as taught, obstacles around the work will be obstructed. And the robot or the work may interfere with each other. For this reason, the teaching point indicating at least one of the position and the posture of the robot is changed to make it different from the time when the gripping position and the posture, which are the positions where the workpiece is gripped, are taught. Alternatively, attempts have been made to avoid interference with the work.

Patent Literature 1 discloses a technology that defines a permissible change amount of each teaching point and determines whether the change amount of each teaching point is within a permissible amount range when an interference avoidance correction of an operation program is performed. Have been.

JP-A-2015-231640

However, the invention disclosed in Patent Literature 1 does not consider changes in the gripping position and posture of the work in the operation after changing the gripping position from the teaching point to avoid interference. Therefore, when the gripping position and posture of the work are corrected by the interference avoidance, the assembling fails because the gripping position and posture of the work are different from those taught when the gripping operation such as assembling and fitting is performed. there's a possibility that.

Therefore, it has been desired to implement an interference avoidance technique that takes into account that the gripping position and posture of a workpiece change with interference avoidance.

The present invention has been made in view of the above, and when processing for avoiding interference is performed and the gripping position and posture of the workpiece are different from those at the time of teaching, the operation after gripping the workpiece fails. It is an object of the present invention to obtain a robot control device in which noise is suppressed.

In order to solve the above-described problems and achieve the object, the present invention provides a storage unit that stores a robot program including a teaching point indicating at least one of a position and a posture of a robot, An interference avoidance processing unit that performs an interference avoidance process that avoids the robot or the work from interfering with an obstacle; and a grip correction amount that is a correction amount of a grip position of the workpiece and a posture of the work in the interference avoidance process. And a grip correction amount acquisition unit that acquires The present invention is directed to a teaching point acquisition unit that acquires a teaching point, and corrects a teaching point based on a grip correction amount when a grip position and a posture of a workpiece are changed based on a grip correction amount along with interference avoidance processing. And an operation command unit for transmitting an operation command to the robot according to a robot program in which the teaching point is corrected based on the grip correction amount.

The robot control device according to the present invention has an effect that when processing for avoiding interference and the gripping position and posture of the workpiece are different from those at the time of teaching, it is possible to suppress the failure of the operation after gripping the workpiece. Play.

Functional block diagram of a robot control device according to Embodiment 1 of the present invention Flow chart showing the flow of the operation of the robot control device according to the first embodiment. Functional block diagram of a robot control device according to Embodiment 2 of the present invention Flow chart showing the flow of the operation of the robot control device according to the second embodiment. Functional block diagram of a robot control device according to Embodiment 3 of the present invention. Flow chart showing the flow of the operation of the robot control device according to the third embodiment. The figure which shows the structure which implement | achieved the function of the control part which concerns on Embodiment 1, 2, or 3 with hardware. The figure which shows the structure which implement | achieved the function of the control part based on Embodiment 1, 2 or 3 with software.

Hereinafter, a robot control device according to an embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the embodiment.

Embodiment 1 FIG.
FIG. 1 is a functional block diagram of the robot control device according to the first embodiment of the present invention. The robot control device 100 according to the first embodiment includes a control unit 10 that controls the robot 30 and a storage unit 20 that stores a robot program 21 for operating the robot 30. The robot program 21 includes a teaching point group 24. The teaching point group 24 includes at least one teaching point indicating at least one of the position and the posture of the robot 30. The control unit 10 includes an operation group creation unit 11 that groups a part of the teaching points included in the teaching point group 24 to create an operation group 23, an interference avoidance processing unit 12 that performs a process of avoiding interference, A grasping correction amount acquiring unit 13 for acquiring a grasping correction amount based on a result of a process to be avoided, a teaching point acquiring unit 14 for acquiring a teaching point included in the operation group 23, and a teaching point correcting unit 15 for correcting a teaching point And an operation command section 16 for outputting an operation command for operating the robot 30. The storage unit 20 also stores obstacle information 22 indicating the position and shape of an obstacle that may interfere with the robot 30.

The robot 30 has a hand 31 for gripping a work. The hand 31 grips the work according to the operation command output from the operation command unit 16 according to the grip command in the robot program 21, and according to the operation command output from the operation command unit 16 according to the grip release command according to the robot program 21. Release the work. That is, the gripping command is a command for instructing gripping of the work, and the gripping release command is a command for instructing gripping of the workpiece. The hand 31 for gripping the work can be exemplified by a hand gripper for holding the work, a suction end effector by air suction, and a suction end effector by magnetic force. Therefore, examples of the gripping command and the gripping release command include a command for instructing opening and closing of the hand 31 and a command for instructing on / off of suction. However, the method of sucking the work by the hand 31 is not limited to the illustrated method.

The operation group creating unit 11 can be set to either a manual mode for grouping teaching points specified by a user input operation or an automatic mode for analyzing the robot program 21 to group teaching points. When the operation group creation unit 11 is set to the manual mode, the operation group creation unit 11 creates an operation group 23 by grouping the teaching points tagged by selection by the user when creating the robot program 21. I do. When the operation group creation unit 11 is set to the automatic mode, the operation group creation unit 11 detects a gripping command and a grip release command in the robot program 21 and teaches while the robot 30 is operating while gripping an object. It is determined whether or not the point is a point, and the teaching points while grasping the object are grouped to create an operation group 23.

(4) By setting the operation group creation unit 11 to the manual mode, even if the robot 30 is teaching points while grasping an object, it is possible to exclude the teaching point from the operation group 23. Therefore, if the user wants to operate the robot 30 at the joint angle taught by the user for the purpose of optimizing the operation speed of the robot 30, even if the robot 30 is at a teaching point while grasping an object, the operation group 23 Can be excluded.

(4) By setting the operation group creation unit 11 to the automatic mode, the user does not need to perform an operation of specifying a teaching point to be included in the operation group 23, and thus labor can be saved. Further, it is possible to avoid occurrence of human error such as omission of selection of teaching points to be grouped.

Even when the operation group creation unit 11 is manually set, the robot 30 can be analyzed by analyzing the robot program 21 or detecting a gripping command and a gripping release command while the robot 30 is operating. It is possible to determine whether or not a teaching point that seems not to hold the object is included in the motion group 23. By issuing a warning and notifying the user when a teaching point that seems to be not holding the object by the robot 30 is included in the operation group 23, it is possible to prevent unnecessary teaching points from being grouped. .

Further, when the operation group creating unit 11 is manually set, the operation group creating unit 11 detects teaching points related to a series of operations of gripping an object by the robot 30 and presents the teaching points to the user. By allowing the user to select teaching points to be grouped from among the above, mistakes in selecting teaching points can be reduced.

The interference avoidance processing unit 12 determines whether or not to perform processing for avoiding interference during the operation of the robot 30 based on the obstacle information 22 stored in the storage unit 20 and the robot program 21.

(4) When the process of avoiding the interference is performed, the work is gripped by the robot 30 at a gripping position and a posture different from the gripping position and the posture at the time of teaching. Therefore, the grip correction amount acquired by the grip correction amount acquisition unit 13 is defined as a change amount that changes the grip position and posture at the time of teaching the workpiece to the grip position and posture after performing the process of avoiding interference. .

The acquisition method of the gripping correction amount for avoiding the interference may be an arbitrary calculation method of calculating and acquiring a change amount every time the process of avoiding the interference is performed, or a plurality of correction patterns may be held in advance. Alternatively, a pattern selection method of selecting from among them may be used. In the case of the occasional calculation method, the grip correction amount acquisition unit 13 calculates and acquires the grip correction amount based on the obstacle information 22 and the robot program 21. In the case of the pattern selection method, the grip correction amount acquisition unit 13 reads and acquires the grip correction amount stored in the storage unit 20.

In the case of performing the process of avoiding interference by the calculation method at any time, the process of avoiding interference can be performed at the time of creating the robot program 21 even if the grip correction amount cannot be determined.

When performing a process of avoiding interference by the pattern selection method, the amount of calculation of the gripping correction amount can be reduced.

The teaching point correction unit 15 performs the teaching point correction so that the position and the posture of the workpiece being gripped are not changed even when the gripping position and the attitude of the workpiece are changed in accordance with the processing for avoiding the interference based on the gripping correction amount. The teaching point acquired by the acquiring unit 14 is corrected.

When the grip correction amount and the teaching point to be corrected are described in the tool coordinate system, the same correction as the correction of the gripping position and posture is performed on the teaching point to be corrected, so that the position and the position of the corrected workpiece are corrected. The posture and the position and posture of the workpiece when the process for avoiding the interference is not performed can be made to match. If at least one of the grip correction amount and the teaching point to be corrected is not described in the tool coordinate system, the same correction can be performed by unifying the coordinate system to the tool coordinate system.

FIG. 2 is a flowchart showing a flow of the operation of the robot control device according to the first embodiment. In step S1, the interference avoidance processing unit 12 acquires all the teaching points in the robot program 21, that is, the teaching point group 24. In step S2, the interference avoidance processing unit 12 determines whether it is necessary to perform a process for avoiding interference. If it is necessary to perform the process of avoiding the interference, the result is Yes in step S2, and in step S3, the gripping correction amount acquisition unit 13 acquires the gripping correction amount. In step S4, the interference avoidance processing unit 12 performs a process of avoiding interference, and changes a gripping position and a posture of the work. In step S5, the teaching point acquisition unit 14 acquires the operation group 23 created by the operation group creation unit 11. In step S6, the teaching point acquiring unit 14 determines whether or not an uncorrected teaching point exists among the teaching points included in the operation group 23. If there is an uncorrected teaching point, the result is Yes in step S6, and the teaching point acquiring unit 14 acquires the value of the uncorrected teaching point in the operation group 23 in step S7. In step S8, the teaching point correction unit 15 corrects the teaching point. After step S8, the process returns to step S6.

If there is no uncorrected teaching point among the teaching points included in the operation group 23, the result is No in step S6, and in step S9, the operation command unit 16 corrects the teaching point based on the grip correction amount. According to 21, an operation command is transmitted to the robot 30. In step S10, the operation command unit 16 determines whether to end the operation of the robot 30. If there is another robot program 21 to be executed, the operation of the robot 30 is continued. If there is no other robot program 21 to be executed, the operation of the robot 30 ends. If the operation of the robot 30 is to be ended, the answer is Yes in step S10, and the process ends. If the operation of the robot 30 is not terminated, the result is No in step S10, and the process returns to step S1.

The robot control device 100 according to the first embodiment executes a process of avoiding interference by the teaching point correction unit 15 correcting the teaching point. The robot control device 100 according to Embodiment 1 changes the position and posture of the work at each teaching point in the operation group 23 even when the gripping position and posture of the work change due to the process of avoiding the interference. do not do. Therefore, the robot control device 100 according to the first embodiment can realize the interference avoidance that guarantees that the operation after gripping the work does not fail. Further, since the robot control device 100 according to the first embodiment performs the correction of the teaching point inside the robot control device 100, it is not necessary to add a correction formula of the teaching point in the robot program 21, and the usability is improved. It is possible to avoid the improvement and the complexity of the robot program 21. In the above description, each teaching point in the operation group 23 has been corrected, but the operation group creation unit 11 is omitted, and not only the teaching points in the operation group 23 but also all the teaching points in the teaching point group 24 are The points may be corrected.

Embodiment 2 FIG.
FIG. 3 is a functional block diagram of a robot control device according to Embodiment 2 of the present invention. The robot control device 101 according to the second embodiment includes an operation availability determination unit 17 that determines whether the robot 30 can move to a teaching point in the operation group 23 corrected by the teaching point correction unit 15. The rest is the same as the robot control device 100 according to the first embodiment.

The operation availability determination unit 17 checks whether or not the teaching point in the operation group 23 corrected by the teaching point correction unit 15 is within the operation limit of the robot 30, so that the robot 30 can reach the teaching point. It is determined whether it is possible to move.

The operation limit can be a range in which the position and posture of the robot 30 can be taken in an arbitrary coordinate system, or a range in which the joint angles of the joints of the robot 30 can be taken. The operation limit can be determined by the user setting the range of the translation position and the posture value in the rectangular coordinate system.

The operation limit may be the movable range of the robot 30. Here, the movable range of the robot 30 is a range that the joints of the robot 30 can physically take. The movable range of the robot 30 may be a design value or a value defined by specifications.

Alternatively, the movable range of the robot 30 may be determined by the user specifying a range in which the robot 30 and the devices connected to the robot 30 do not collide with a structure existing around the robot 30. The devices connected to the robot 30 can be exemplified by an end effector and a vision sensor. By simulating the arrangement state of structures around the robot 30 in a simulation space that simulates the operation of the robot 30, the range in which the robot 30 can operate without colliding with the surrounding structures is calculated on the simulation. May be set.

(4) The position of the object around the robot 30 may be acquired by a device such as a laser scanner capable of detecting the position of the object, and the operation limit may be determined based on the acquired position of the object.

The operation limit may be set by combining a plurality of setting methods. A method using both the movable range and the range designation of the rectangular coordinate system can be exemplified, but the method is not limited to this.

FIG. 4 is a flowchart showing a flow of the operation of the robot control device according to the second embodiment. The operation of the robot controller 101 according to the second embodiment is different from the operation of the robot controller 100 according to the first embodiment in that steps S11 and S12 are added after step S8.

After the teaching point correction unit 15 corrects the teaching point in step S8, in step S11, the operation availability determination unit 17 determines whether the corrected teaching point is within the operation limit.

場合 If the corrected teaching point is within the operation limit, the result is Yes in step S11, and the process proceeds to step S6. If the corrected teaching point is not within the range of the operation limit, the result is No in step S11, and in step S12, the operation availability determination unit 17 outputs an error.

The robot controller 101 according to the second embodiment knows beforehand whether or not the corrected teaching point is within the set operation limit when the teaching point in the operation group 23 is corrected by the teaching point correction unit 15. Therefore, an accident such as the robot 30 colliding with a surrounding structure can be prevented.

Embodiment 3 FIG.
FIG. 5 is a functional block diagram of a robot control device according to Embodiment 3 of the present invention. The robot control device 102 according to the third embodiment includes a gripping correction range obtaining unit 18 that obtains a range in which the gripping correction amount can be obtained, and a gripping correction amount changing unit 19 that changes the gripping correction amount in a range in which the gripping correction amount can be obtained. And The rest is the same as the robot control device 101 according to the second embodiment. Hereinafter, a range in which the grip correction amount can be taken is referred to as a grip correction range.

The gripping correction range acquisition unit 18 determines the gripping correction range when the gripping position and posture of the work can be obtained in a range in the process of avoiding interference, that is, when the gripping correction amount is a value having a width instead of a specific value. get.

把持 The grip correction amount that can be taken to avoid interference may not be uniquely determined. Taking a cylindrical work as an example, interference can be avoided by sliding the gripping position in the direction along the cylindrical axis of the work while maintaining the relative posture between the cylindrical work and the end effector of the robot 30. Where possible, the gripping position of the workpiece is not uniquely determined. In such a case, the grip correction range obtaining unit 18 can obtain the grip correction range.

The grip correction range is represented by a range of coordinate values in an arbitrary coordinate system. In the case of the cylindrical work described above, the work coordinate system of the work is set, and when the cylindrical axis direction is the X-axis direction of the work, the maximum and minimum values of X that can avoid interference are set. Good. The fact that the grip correction range is represented by a range of coordinate values means that the candidate values of the grip correction amount take a continuous value.

The grip correction range may be configured by a combination of a plurality of ranges. The grip correction range may be a range in which a plurality of ranges overlap.

The grip correction range may be a set of discrete values instead of a continuous range of coordinate values.

The grip correction amount changing unit 19 changes the grip correction amount based on the grip correction range and the determination result of the operation availability determination unit 17. When the grip correction range is a continuous value, the determination is performed by selecting a value for which the determination result in the operation availability determination unit 17 is allowable from the values within the grip correction range. When the grip correction range is a set of discrete values, the change of the grip correction amount is obtained by acquiring candidate values of the grip correction amount and determining the operation result determination unit 17 from the obtained candidates. This is done by selecting

Examples of the method of acquiring the candidate value include a method of calculating a plurality of gripping correction amounts by dividing the gripping correction range at an arbitrary interval, and a method of randomly extracting gripping positions and postures included in the gripping correction range. When the grip position and orientation included in the grip correction range are extracted at random, the result of the operation possibility determination differs depending on the extracted candidate value, so there is a possibility that interference avoidance may be successful by re-extracting the candidate value. .

FIG. 6 is a flowchart showing a flow of the operation of the robot control device according to the third embodiment. The operation of the robot control device 102 according to the third embodiment differs from the operation of the robot control device 101 according to the second embodiment in that steps S21, S22, and S23 are added after step S11. ing.

If the operation possibility determination unit 17 determines that the corrected teaching point is not within the range of the operation limit in step S11, the result is No in step S11, and in step S21, the grip correction amount changing unit 19 determines the grip correction amount. Determine whether to change. When the grip correction amount is changed, the answer is Yes in step S21, and in step S22, the grip correction range obtaining unit 18 obtains the grip correction range. In step S23, the grip correction amount changing unit 19 changes the grip correction amount within the grip correction range. After step S23, the process proceeds to step S5.

On the other hand, if the grip correction amount is not changed, No is obtained in step S21, and the process proceeds to step S12.

As described above, in the robot control device 102 according to the third embodiment, the grip correction amount has a plurality of candidate values within the grip correction range, and any of the candidate values within the grip correction range is used as the grip correction amount. When the corrected teaching point is not within the operation limit, the grip correction amount is changed to another candidate value, and it is determined whether the corrected teaching point is within the operation limit. Can be. When the correction is performed using the uniquely determined grip correction amount, there is a concern that the robot may not move to the corrected teaching point depending on the operation of the robot after gripping due to being outside the operation limit. According to the robot control apparatus 102 according to the third embodiment, the grip correction amount can be corrected so that the robot 30 can move within a range where interference can be avoided. This makes it possible to easily adjust the operation of the robot 30 and reduce the number of stops.

The function of the control unit 10 according to the first, second, or third embodiment is realized by a processing circuit. The processing circuit may be dedicated hardware or an arithmetic device that executes a program stored in a storage device.

If the processing circuit is dedicated hardware, the processing circuit may be a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an application specific integrated circuit, a field programmable gate array, or a combination thereof. Is applicable. FIG. 7 is a diagram illustrating a configuration in which the function of the control unit according to the first, second, or third embodiment is realized by hardware. The processing circuit 29 incorporates a logic circuit 29a for realizing the function of the control unit 10. The hardware that implements the processing circuit 29 can be exemplified by a microcontroller.

When the processing circuit 29 is an arithmetic unit, the function of the control unit 10 is realized by software, firmware, or a combination of software and firmware.

FIG. 8 is a diagram illustrating a configuration in which the function of the control unit according to the first, second, or third embodiment is realized by software. The processing circuit 29 has a central processing unit 291 for executing the program 29b, a random access memory 292 used by the central processing unit 291 for a work area, and a storage device 293 for storing the program 29b. The functions of the control unit 10 are realized by the central processing unit 291 expanding and executing the program 29b stored in the storage device 293 on the random access memory 292. The software or firmware is described in a programming language and stored in the storage device 293.

The processing circuit 29 implements the function of the control unit 10 by reading and executing the program 29b stored in the storage device 293. It can be said that the program 29b causes a computer to execute a procedure and a method for realizing the function of the control unit 10.

Note that the processing circuit 29 may be partially realized by dedicated hardware and partially realized by software or firmware.

As described above, the processing circuit 29 can realize the above-described functions by hardware, software, firmware, or a combination thereof.

The configurations described in the above embodiments are merely examples of the contents of the present invention, and can be combined with other known technologies, and can be combined with other known technologies without departing from the gist of the present invention. Parts can be omitted or changed.

10 control unit, 11 operation group creation unit, 12 interference avoidance processing unit, 13 grip correction amount acquisition unit, 14 teaching point acquisition unit, 15 teaching point correction unit, 16 operation instruction unit, 17 operation possibility determination unit, 18 grip correction range Acquisition unit, 19 grip correction amount change unit, 20 storage unit, 21 robot program, 22 obstacle information, 23 operation group, 24 teaching point group, 29 processing circuit, 29a logic circuit, 29b program, 30 robot, 31 hand, 100 , 101, 102 {robot control unit, 291} central processing unit, 292 {random access memory, 293} storage unit.

Claims

A storage unit that stores a robot program including a teaching point indicating at least one of a position and a posture of the robot,
When the robot grips a work, an interference avoidance processing unit that performs an interference avoidance process that avoids the robot or the work from interfering with an obstacle,
In the interference avoidance processing, a gripping correction amount obtaining unit that obtains a gripping correction amount that is a correction amount of a gripping position of the work and a posture of the work held by the robot,
A teaching point acquisition unit for acquiring the teaching point,
A teaching point correction unit that corrects the teaching point based on the grip correction amount, when the grip position and the posture of the work are changed based on the grip correction amount along with the interference avoidance processing;
An operation command unit for transmitting an operation command to the robot in accordance with the robot program in which the teaching point is corrected based on the grip correction amount.
An operation availability determination unit that determines whether the corrected teaching point is within the operation limit of the robot and issues a warning when the teaching point is not within the operation limit. 2. The robot control device according to 1.
The grip correction amount has a plurality of candidate values within a grip correction range,
If any of the candidate values within the gripping correction range is the gripping correction amount and the corrected teaching point is not within the range of the operation limit, the gripping correction amount is changed to another candidate value. 3. The robot control device according to claim 2, wherein the controller further determines whether the corrected teaching point is within the range of the operation limit.
4. The robot controller according to claim 3, wherein the grip correction amount is changed to another candidate value selected at random.
An operation group creation unit that creates an operation group by grouping two or more of the teaching points included in the robot program,
The operation group creation unit detects a command for instructing gripping and a command for releasing gripping in the robot program, and extracts the teaching point in a state where the robot grips the workpiece. Group
The teaching point acquisition unit acquires the teaching point included in the operation group,
The robot control device according to claim 1, wherein the teaching point correction unit corrects the teaching points included in the operation group based on the grip correction amount.