JP5078770B2 - Teaching data verification method for articulated robots - Google Patents

Description

  According to the present invention, new first teaching data of an articulated robot indicating work operations performed on a plurality of work points in a first work is provided as new articulation data indicating work operations performed on a plurality of work points in a second work. The present invention relates to a teaching data verification method for an articulated robot for verifying based on existing second teaching data of a robot.

  For example, when spot welding is performed on a plurality of work points using an articulated robot with respect to an automobile frame, a number of work points are combined into a series of processes to realize the operation of the processes. Create teaching data for articulated robots.

  In recent teaching data, off-line teaching has been put into practical use in which a model of a multi-joint robot, a work that is a work target, and surrounding structures is constructed on a computer, and teaching data is created using this model.

  Japanese Patent Application Laid-Open No. 2004-228620 proposes to create new teaching data by using / converting existing teaching data as a method for creating teaching data.

JP 2004-362018 A

  By the way, the teaching data created by off-line teaching or the like must be verified for various aptitudes before being actually applied on the production line. It takes a considerable amount of time, especially when the number of work points is large.

  In addition, when existing teaching data exists as in Patent Document 1, depending on the work point, almost the same verification as that performed on the teaching data may be performed on newly created teaching data. Efficiency.

  In particular, when there is another car model that is quite similar to the past, such as when a minor model change of the car, and there is teaching data corresponding to the car model, if possible, the data is It is desirable to use in.

  The present invention has been made in consideration of such problems, and an object of the present invention is to provide a teaching data verification method for an articulated robot capable of efficiently verifying newly created teaching data.

  According to the teaching data verification method for an articulated robot according to the present invention, new first teaching data of an articulated robot indicating work operations performed on a plurality of work points in a first work is obtained, and a plurality of work points in a second work are obtained. A teaching data verification method for an articulated robot for verifying based on the existing second teaching data of the articulated robot indicating a work operation to be performed for a predetermined work point in the first teaching data. Data as comparison object data, work point data in the second teaching data corresponding to the comparison object data as comparison reference data, position data of corresponding work points from the comparison object data and the comparison reference data, A corner of a working unit that is provided in the articulated robot and works on the working point. Based on at least one of the step of obtaining at least one of the data, the step of obtaining the position difference between the obtained position data and the angle difference of the angle data, and the position difference and the angle difference, And a step of verifying the comparison target data.

  As described above, the type of verification to be executed is limited by changing the type of verification of data related to a predetermined work point based on at least one of the position difference and the angle difference, and the newly created first teaching data is efficient. Can be verified.

  According to the teaching data verification method for an articulated robot according to the present invention, the type of verification to be executed is limited by changing the type of data verification related to a predetermined work point based on at least one of the position difference and the angle difference. The newly created first teaching data can be efficiently verified.

  The teaching data verification method for an articulated robot according to the present invention will be described below with reference to FIGS.

  FIG. 1 shows a configuration of an off-line teaching apparatus 10 to which the teaching data verification method for an articulated robot according to the present embodiment is applied, and a multi-joint robot 12 to which teaching data created by the off-line teaching apparatus 10 is applied. .

  The articulated robot 12 is an industrial articulated robot, and is disposed along with a robot control unit 24 on a production line at a site where a vehicle is manufactured. The articulated robot 12 has a base portion 14, a first arm 16, a second arm 18, and a third arm 20 in order with reference to the base portion 14, and a welding gun at the tip of the third arm 20. The end effector 22 is provided. The end effector 22 is detachable from the third arm 20. The first arm 16 can be rotated by axes J1 and J2 that can be rotated horizontally and vertically with respect to the base portion 14. The second arm 18 is connected to the first arm 16 so as to be rotatable about the axis J3. The second arm 18 can be twisted and rotated by the axis J4. The third arm 20 is connected to the second arm 18 so as to be rotatable about an axis J5. The third arm 20 can be twisted and rotated by the axis J6. Each of the shaft J4 and the shaft J6 can be twisted and rotated by 360 ° or more.

  The end effector 22 is a C-type welding gun having a pair of electrodes (working portions) 22a and 22b that open and close on the axis L. When the electrodes 22a and 22b are in a closed state, the end effector 22 operates on the axis L (hereinafter referred to as TCP). (Referred to as “Tool Center Point”).

  The electrodes 22a and 22b are working portions that perform welding work on work points Pn and Qn (n is a subscript indicating the work order) described later.

The parameter Z _T is defined with reference to the direction that coincides with the axis of the electrodes 22a and 22b on the main body side from the TCP, and the parameter X _T with reference to the direction that is orthogonal to the axis of the electrodes 22a and 22b and that faces the outside of the end effector 22. Is specified. The parameter Y _T is defined with reference to directions orthogonal to the axial direction of the electrodes 22 a and 22 b and the direction toward the outside of the end effector 22.

  The position of the TCP is represented by a world coordinate system of three axes X, Y, and Z that are orthogonal to each other. The origin of this world coordinate system is provided at the base end portion of the articulated robot 12, for example, as shown in FIG.

  The driving mechanisms of the axes J1, J2, J3, J4, J5 and J6 and the opening / closing mechanisms of the electrodes 22a and 22b are driven by actuators (not shown), respectively, and the TCP coordinates are the rotation angles of the axes J1 to J6 and the articulated robot 12. It is determined by the dimensions of each part.

  By the operation of the multi-joint robot 12 having such a six-axis configuration, the end effector 22 connected to the tip can be arranged in an arbitrary direction with respect to the workpiece on the production line. In other words, the end effector 22 can move with six degrees of freedom. The articulated robot 12 may have an operation unit such as an expansion / contraction operation and a parallel link operation in addition to the rotation operation.

  The articulated robot 12 operates according to teaching data set in the robot control unit 24.

  As shown in FIG. 2, the off-line teaching device 10 is configured by a computer. The control unit 26 of the offline teaching apparatus 10 includes a CPU 28 that controls the entire offline teaching apparatus 10, a ROM 30 and a RAM 32 that are recording units, a hard disk 36 that reads and writes data by a hard disk drive (HDD) 34, and a flexible disk A recording medium drive 40 that reads and writes teaching data from and to an external recording medium 38 such as a compact disc, a teaching data creation circuit 42 that creates teaching data for the articulated robot 12, and the created teaching data A simulation circuit 44 that performs operation simulation of the articulated robot 12 and a verification circuit 45 that performs operation verification of the articulated robot based on teaching data are provided. A display 46 for assisting teaching work by an operator, displaying a simulation image, and the like is connected to the control unit 26 via a drawing control circuit 48 and a keyboard 52 as an input device via an interface 50. And a mouse 54 are connected.

  The verification circuit 45 sets the articulated robot 12 in a predetermined posture in the virtual space, performs first verification for verifying the presence or absence of interference with other structures, and the operation speed and smoothness when performing a predetermined operation. A second verification can be performed. In other words, the first verification is a verification of the feasibility of whether or not a series of operations can be realized, and the second verification is a verification of the validity and suitability of a series of operations separately from the realization. It is verification. The structure as the target of the presence or absence of interference performed in the first verification is a structure other than the articulated robot 12, for example, a workpiece or another articulated robot arranged in the vicinity. As the second verification, for example, the movement time from the previous work point to the work point to be verified and the degree of smoothness of the movement are determined based on a predetermined threshold.

  In the hard disk 36, a teaching data creation program 56 for creating teaching data for the articulated robot 12, shape data 58 relating to the articulated robot 12, work objects and other equipment, and each axis of the articulated robot 12 are stored. The robot specification data 60 including the operation specifications, the first teaching data 104 and the second teaching data 106 are recorded.

  The first teaching data 104 is used when the articulated robot 12 performs welding work operation on a series of work points on the door frame of the first vehicle 100 (see FIG. 3) and is newly created. And is set based on the absolute coordinate value (“TCP position” in FIG. 4) of the work point Pn.

  The second teaching data 106 is used when verifying the first teaching data 104 and when performing a welding work operation on a series of a plurality of work points on the door frame of the second vehicle 102 (see FIG. 3). , Existing data. In addition to the first teaching data 104 and the second teaching data 106, a plurality of teaching data are stored in the hard disk 36.

  Next, a procedure for verifying the first teaching data 104 (see FIG. 4) will be described. The verification of the first teaching data 104 is performed based on a vehicle other than the first vehicle 100, for example, the second teaching data 106 (see FIG. 5). The first vehicle 100 is a minor change model of the second vehicle 102, and the shape of the door frame is slightly different. The second teaching data 106 is applied to the second vehicle 102 and is a proven existing data. The operation of the articulated robot 12 based on the second teaching data 106 is at least without interference with other structures, and It has been verified that a reasonably quick and smooth operation can be realized.

  The articulated robot 12 performs welding sequentially on the seven work points P1 to P7 for the first vehicle 100, and sequentially welds eight work points Q1 to Q8 for the second vehicle 102. Yes. Actually, in addition to the work points P1 to P7 and Q1 to Q8, a predetermined work start point, a work end point, an entry start point for the work point, a retreat point from the work point, a work relay point, etc. are set. These points are omitted so as not to complicate the description. Regarding the first vehicle 100 and the second vehicle 102, the parts other than the work points P1 to P7 and the work points Q1 to Q8 are welded simultaneously and in parallel by another multi-joint robot (not shown).

As shown in FIG. 4, the first teaching data 104 indicating the operation of the articulated robot 12 with respect to the first vehicle 100 is composed of a “gun unit orientation” column, a “TCP position” column, and an “each axis angle” column. Has been. The “orientation of the gun unit” column is coordinates indicating the attitude of the end effector 22, that is, tool coordinate data, and the parameters X _T , Y _T , and Z _T are recorded therein. Data indicating the absolute coordinates of the end effector 22 is recorded in the “TCP position” column. The first teaching data 104 is represented as a route including seven work points P <b> 1 to P <b> 7 in the first vehicle 100.

  The “each axis angle” column includes rotation angles θ1 to θ6, and each rotation angle θ1 to θ6 indicates the rotation angle of each axis J1 to J6.

  FIG. 5 shows second teaching data 106 indicating the operation of the articulated robot 12 with respect to the second vehicle 102. As is apparent from FIGS. 4 and 5, the first teaching data 104 and the second teaching data 106 have the same configuration as the framework, and only the data contents are different. The second teaching data 106 is represented as a route including eight work points Q1 to Q8 in the second vehicle 102.

  Next, a verification method for creating the first teaching data 104 and verifying it will be described.

  First, in step S1 of FIG. 6, the position data of the work points P1 to P7 and the data of the orientation of the end effector 22 are read from the predetermined storage unit as basic data, and the “TCP position” column of the first teaching data 104 and Write in the "Gun Unit Orientation" field. The orientation of the end effector 22 is set in advance based on the TCP position data and the orientation of the work surface in the first vehicle 100 corresponding to the position data. The orientation of the end effector 22 is basically set so that the electrodes 22a and 22b are perpendicular to the work surface at each work point. Thus, welding can be efficiently performed by setting the electrodes 22a and 22b so as to be perpendicular to the work surface.

  In step S2, the existing teaching data is compared with the first teaching data 104 at that time, and the data having the closest values in the “TCP position” column and the “Gun unit orientation” column is selected as comparison reference data. .

  This selection process is performed by the operator's judgment according to the design condition, or by the computer's automatic judgment. As described above, when the first vehicle 100 is a minor change model of the second vehicle 102 and the shape of the door frame is slightly different, the first teaching data 104 and the second teaching data 106 correspond to each other. It is clear that the second teaching data 106 may be used as comparison reference data at the discretion of the operator.

  If there is no data that is clearly similar to the first teaching data 104, or if it is unknown that any of the teaching data is similar to the first teaching data 104, the existing teaching data What is necessary is just to compare with the 1st teaching data 104 with a computer, for example, a correlation coefficient etc. is calculated | required and what has the highest similarity should just be selected.

In step S3, the first teaching data 104 is set by obtaining all parameters for the work points P1 to P7. As the processing in step S3, for example, the second teaching data 106 may be obtained by conversion as in the method described in Patent Document 1, or the parameters X _T , Y _T , Z _T , X, Based on Y and Z, each axis angle θ1 to θ6 may be obtained by a known matrix inverse transformation operation. Alternatively, it may be obtained by performing offline teaching while using the parameters X _T , Y _T , Z _T , X, Y and Z and moving the articulated robot 12 in the virtual space. The shaft angles θ <b> 1 to θ <b> 6 are set within each axis operation range of the articulated robot 12.

In step S3, the shaft angles θ1 to θ6 are obtained for the work points P1 to P7, and the initial parameters X _T , Y _T , and Z _T may be slightly changed as necessary.

  In step S4, the simulation circuit 44 performs an operation simulation of the articulated robot 12 based on the created first teaching data 104, and confirms that the end effector 22 is normally arranged with respect to the work points P1 to P7. To do.

  In step S5, the seven work points P1 to P7 of the first teaching data 104 are associated with the eight work points Q1 to Q8 of the second teaching data 106 of the comparison reference data. Basically, the TCP positions represented by the parameters X, Y, and Z may be associated with each other. In the example shown in FIG. 3, the work points P1 to P7 of the first teaching data 104 are sequentially The work points Q1 to Q7 of the second teaching data 106 may be associated with each other. When the number of work points Pn in the first teaching data 104 and the number of work points Qn in the second teaching data 106 are the same, the correspondence may be made as it is in the work order. The data of the work point Pn in the first teaching data 104 is set as comparison target data, and the data of the work point Qn in the second teaching data 106 corresponding to the comparison target data is set as comparison reference data.

  In step S6, the position data of the corresponding working points Pn and Qn and the angle data of the electrodes 22a and 22b as the working parts are obtained from the comparison target data and the comparison reference data, respectively.

The position data here is the TCP position, and the data in the “TCP position” column in the first teaching data 104 and the second teaching data 106, that is, the parameters X, Y, and Z can be used as they are. The angle data is data indicating the inclination of the axis L of the electrodes 22a and 22b, and is obtained from the data in the “Gun unit orientation” column, that is, the parameters X _T , Y _T and Z _T.

  In step S7, the position difference ΔA of the TCP position data and the angle difference ΔB of the electrodes 22a and 22b as the working parts are obtained for each corresponding work point using the first teaching data 104 and the second teaching data 106.

The position difference ΔA of the TCP position data corresponds to the space distance between the work points. For example, ΔA = √ ((XP1-XQ1) ² + (YP1-YQ1) for the work point P1 and the work point Q1. ² + (ZP1-ZQ1) ² ). FIG. 7 shows the relationship between the work point P1, the work point Q1, and the position difference ΔA.

As shown in FIG. 8, the angle difference ΔB is based on the postures of the electrodes 22a and 22b (shown by solid lines in FIG. 8) related to a predetermined work point (P1 in FIG. 8) in the first teaching data 104 and the second teaching. This corresponds to the angle difference between the inclinations of the axis L of the electrodes 22a and 22b (shown by broken lines in FIG. 8) related to the associated work point (Q1 in FIG. 8) in the data 106, and parameters X _T , Y _T , Z _Calculated based on _T. In FIG. 8, the work point P1 and the work point Q1 are shown to coincide with each other for easy understanding.

  In subsequent steps S8 to S15, the type of verification performed on the posture of the articulated robot 12 is changed for the first teaching data 104 based on the position difference ΔA and the angle difference ΔB.

  In step S8, the work point Pn is selected as comparison target data to be verified in the first teaching data 104. Basically, the work points P1 to P7 may be selected as verification targets in this order. The work point Qn corresponding to this becomes comparison reference data.

  In step S9, the position difference ΔA is compared with the first position threshold value R1, and when ΔA ≧ R1, the process proceeds to step S10, and otherwise, the process proceeds to step S11.

  Step S10 is a case where the work point P1 is outside the sphere having the radius R1 (that is, the first position threshold value R1) centered on the work point Q1 in FIG. 7, and the position is considerably shifted. Rather than relying on the results of the verification performed with the second teaching data 106, both the first verification and the second verification are performed again to ensure sufficient reliability. Thereafter, the process proceeds to step S15.

  In step S11, the angle difference ΔB is compared with the angle threshold value U. If ΔB ≧ U, the process proceeds to step S12. Otherwise, the process proceeds to step S13.

  In step S12, both the first verification and the second verification are performed. This is because when the angle difference ΔB is large, the change in the posture of the end effector 22 is large and the influence on the operation is large. Thereafter, the process proceeds to step S15.

  In step S13, the position difference ΔA is compared with the second position threshold value R2 smaller than the first position threshold value R1, and when ΔA ≧ R2, the process proceeds to step S14. Otherwise, the first verification and the second verification are performed. Skip to step S15.

  Step S14 is a case where the work point P1 is inside the sphere having the radius R1 centered on the work point Q1 and outside the sphere having the radius R2 (that is, the second position threshold R2) in FIG. It is considered that the deviation is relatively small and the results of verification performed with the second teaching data 106 can be used to some extent, and the second verification for suitability is omitted, but the first verification for feasibility is executed. In this case, even if the suitability is somewhat reduced, there is almost no hindrance to the series of operations. Thereafter, the process proceeds to step S15.

  In step S15, it is confirmed whether or not the processing has been completed for all the work points P1 to P7 of the first teaching data 104, and if not completed, the process returns to step S8.

  In each verification, if it is determined that a predetermined verification criterion is not satisfied, the corresponding data is corrected by a predetermined means.

  As described above, according to the teaching data verification method of the articulated robot according to the present embodiment, by changing the type of data verification related to the predetermined work point Pn based on the position difference ΔA and the angle difference ΔB, The types of verification to be performed are limited, and the newly created first teaching data 104 can be efficiently verified.

  In the above embodiment, the type of data verification related to the predetermined work point Pn is changed based on the position difference ΔA and the angle difference ΔB. For example, the welding work surfaces in the first vehicle 100 and the second vehicle are almost in the same direction. If the electrodes 22a and 22b are in direct contact with the welding work surface, the angle difference ΔB may be substantially ignored. In this case, the process shown in FIG. 9 may be performed. Steps S101 to S110 and S111 to S113 in FIG. 9 correspond to steps S1 to S10 and S13 to S15 in FIG.

  However, in step S106, only the position data is acquired, and it is not necessary to acquire the angle data as in step S6. In step S107, only the position difference ΔA is obtained, and the angle difference ΔB as in step S7 is unnecessary. . Further, the processing corresponding to steps S11 and S12 of the determination processing based on the angle difference ΔB in FIG. 6 is not necessary in FIG.

  As described above, depending on the design conditions, at least one of the position data and the angle data is acquired, and at least one of the position difference ΔA and the angle difference ΔB is obtained. Based on at least one of the position difference ΔA and the angle difference ΔB. Verification may be performed.

  The teaching data verification method for an articulated robot according to the present invention is not limited to the above-described embodiment, and various steps can be taken without departing from the gist of the present invention.

This is an offline teaching apparatus to which the teaching data verification method for an articulated robot according to the present embodiment is applied. It is a circuit block diagram of an off-line teaching device. It is a schematic diagram which shows the work point and work path | route by the 1st teaching data and 2nd teaching data which show operation | movement of the articulated robot with respect to a workpiece | work. It is a table which shows the content of the 1st teaching data. It is a table which shows the content of the 2nd teaching data. It is a flowchart of the teaching data verification method of the present embodiment. It is a schematic diagram which shows the relationship between the position difference of two work points, a 1st position threshold value, and a 2nd position threshold value. It is a schematic diagram which shows the relationship between an electrode and an angle difference. It is a flowchart of the teaching data verification method which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Offline teaching apparatus 12 ... Articulated robot 22 ... End effector 22a, 22b ... Electrode 24 ... Robot control part 42 ... Teaching data creation circuit 44 ... Simulation circuit 45 ... Verification circuit 100 ... 1st vehicle (1st workpiece | work) 102 ... Second vehicle (second work)
104 ... first teaching data 106 ... second teaching data Pn, Qn ... work point U ... angle threshold R1 ... first position threshold R2 ... second position threshold ΔA ... position difference ΔB ... angle difference

Claims (2)

The new first teaching data of the multi-joint robot showing work operations performed on a plurality of work points in the first work is obtained from the existing one of the multi-joint robots showing work operations performed on the plurality of work points in the second work. A method for verifying teaching data of an articulated robot for verifying based on the second teaching data of
Data of a predetermined work point in the first teaching data is set as comparison target data, data of a work point in the second teaching data corresponding to the comparison target data is set as comparison reference data, and the comparison target data and the comparison reference data Obtaining at least one of position data of a corresponding work point from each and angle data of a working unit provided to the articulated robot and working with respect to the work point;
Obtaining at least one of a position difference between the acquired position data and an angle difference between the angle data;
Verifying the comparison target data based on at least one of the position difference and the angle difference;
I have a,
The step of performing the verification includes
When the position difference is equal to or greater than a first position threshold value, or when the angle difference is equal to or greater than an angle threshold value, first verification for verifying the presence or absence of interference with other components of the articulated robot; and Perform a second verification to verify the motion speed or smoothness of the articulated robot,
When the position difference is less than the first position threshold and greater than or equal to the second position threshold smaller than the first position threshold, the first verification is performed without performing the second verification. Robot teaching data verification method. The teaching data verification method for an articulated robot according to claim 1,
The step of performing the verification includes
When the position difference is less than the second position threshold and the angle difference is less than the angle threshold, the first verification and the second verification are not performed.
Teaching data verification method for articulated robots.

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