JP3040906B2 - Robot operation time evaluation method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention calculates and integrates the time required for each work during offline teaching of a work robot such as a welding robot or an assembly robot to obtain a preset cycle time (work time). The present invention relates to a method and an apparatus for evaluating the operation time of a robot having a function of outputting (displaying, etc.) in real time in comparison.

[0002]

2. Description of the Related Art In various manufacturing factories, a manufacturing automation system using a working robot such as a welding robot or an assembly robot is employed. For example, in a production line of an automobile, various operation robots for performing welding and assembly in accordance with a manufacturing process are arranged, and a predetermined member is transported and supplied under computer control to automatically perform production.

In order to cause these work robots to perform required work, generally, a series of work commands (operation programs) are sent to a robot controller that controls the operation of the work robot using a teaching device. Under the control of a central computer, each robot controller sequentially supplies work instructions to subordinate work robots, and causes each work robot to perform required operations.

For example, a welding process in a welding robot includes a movement from an operation origin position of the robot to a predetermined welding position, current welding at predetermined welding conditions at the welding position,
It is composed of steps such as returning to the operation origin position and waiting between operations that occur in relation to the operation time in the previous step. It should be noted that, depending on the operation process, there is a case where one cycle of the welding process is constituted by an operation of continuously moving to a plurality of welding positions, performing welding, and returning to the origin position.

Therefore, when teaching to a robot controller using a teaching device, the position data, speed data and movement command from the robot origin position to the welding position, the energizing time at the welding position (preliminary energizing is required) If the work at the next welding position is performed continuously, the position data, speed data and movement command up to the next welding position, and the welding command, including the welding time, etc. Welding conditions and welding commands,
Move commands to the robot home position are sequentially stored in the robot controller in the order of work, and simulation of operation is performed between the teaching device and the robot controller, or actual operation check for actually operating the robot is performed. By measuring the required time (cycle time) and feeding the result back to the teaching work to correct the teaching data,
Some measures have been taken to reduce the time required for each operation. In this simulation or the like, an interference check between the robot and the work may be performed as necessary.

As a conventional technique of this kind, a technique disclosed in Japanese Patent Application Laid-Open No. Hei 5-6216 by the present applicant or a technique disclosed in Japanese Patent Application Laid-Open No. Hei 3-184795 is known. The former measures and displays the required time for each operation of the robot and the required time (cycle time) for each work process by a measuring means provided in the robot controller, and the latter measures a plurality of robots. When performing a series of work processes using not only the total cycle time for each work process of each robot but also the actual operation time and waiting time for each basic operation of each robot at the stage of motion simulation The time is measured and displayed separately from the time, and a more detailed and accurate cycle time is obtained before starting actual production.

[0007]

However, in each case, the prior art described above requires a cycle time measured after completion of each work process (one cycle) of the robot or after simulation and a preset cycle time. In other words, the cycle time (working time) can be determined only after actually operating the robot or simulating the actual operation. Therefore, in the system for teaching the robot controller using the teaching device as described above, after one cycle of teaching is completed,
The cycle time (working time) can be confirmed for the first time by performing a simulation, and the result is compared with a preset cycle time.
There was a problem that a method of verifying the relationship between the teaching data and the actual working time had to be taken.

For this reason, in the conventional technique, a cycle time (work time) obtained by performing a simulation and a preset cycle time are compared and evaluated, and, for example, an actual cycle time (work time) is set. If the cycle time is exceeded, the teaching data must be corrected so as to be within the set cycle time, and the simulation operation must be repeated, resulting in an inconvenience of increasing the number of teaching steps. Accurately matching the actual cycle time (working time) of the robot to the preset cycle time has an effect on the teaching work at the production site and, consequently, the production efficiency, and increases the number of teaching man-hours. Instead, during the teaching data verification stage,
A method that can guarantee a highly accurate cycle time is desired.

Further, in the conventional technology, in which the simulation is performed after the completion of one cycle of teaching and the cycle time (working time) has to be confirmed for the first time, the evaluation of the robot, the welding gun and the like cannot be performed in real time. If the situation is changed, such as a design change, a layout change in a production process, or a distribution of hit points, the teaching may be repaired in response to the situation, requiring a large number of man-hours.

The present invention solves the above-mentioned inconveniences. In offline teaching of a working robot such as a welding robot or an assembly robot, the time required for each work and the time required for one step of the work are calculated. It is an object of the present invention to provide a method and an apparatus for evaluating the operation time of a robot having a function of integrating (accumulating), comparing with a preset cycle time (work time), and outputting (displaying, etc.) in real time.

[0011]

In order to achieve the above object, a method according to the present invention comprises a teaching device for a robot.
The robot operation time evaluation method when correcting data
There are, in accordance with parameters including the distance and velocity leading to the target position from the current position of the robot, the method comprising the robot calculates the moving time required to move to the target position, in accordance with the working conditions at the target position, the Calculating a working time at the target position, and calculating an added value by adding the moving time and the working time ;
A step of obtaining the integrated value by integrating the added value in a plurality of work processes, and a cycle time and the integrated value of the robot set in advance for the plurality of work processes ,
A step of comparing each process of the work process and outputting warning information when the integrated value exceeds the cycle time, and processing when the warning is output.
And identifying the work process .

Further, the apparatus according to the present invention provides a robot
When the robot moves when correcting the teaching data
Be between evaluation device, in accordance with parameters including the distance and velocity leading to the target position from the current position of the robot, the movement time calculating means to which the robot calculates the moving time required to move to the target position, the target A work time calculating means for calculating a work time at the target position in accordance with a work condition at the position; an addition value obtained by adding the movement time and the work time;
An integrating means for integrating in each step, and a cycle time of the robot set in advance for the plurality of operation steps and an integrated value obtained by the integrating means, for each of the operations.
Comparing means for comparing each process, and outputting the warning information when the integrated value exceeds the cycle time.
In addition, the work process related to the processing when the warning is output
Output means for specifying a process.

[0013]

In the method and apparatus for evaluating the operation time of a robot according to the present invention, when correcting the teaching data of the robot, the movement required for the movement according to the parameters given for moving the robot to the target position. A time is calculated, a work time at the target position is calculated according to a work condition at the target position, and the movement time and the work time are integrated in a plurality of work steps . Then, the cycle time of the robot in the plurality of work steps set in advance and the integrated value are converted into the respective work steps.
Compared in real time for each of the processing, when the integrated value exceeds the cycle time, and outputs warning information DOO
In addition, work processes related to the processing when the warning is output
Specify .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for evaluating the operation time of a robot according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a logical configuration diagram of a control circuit in an off-line teaching device embodying the present invention, FIG. 2 is a block diagram showing a configuration of a control circuit in the teaching device, and FIG. 3 is a block diagram of the off-line teaching device. FIG. 2 is a block diagram illustrating an entire configuration.

In FIG. 3, reference numeral 10 denotes an off-line teaching device, and reference numerals 12a, 12
b indicates a robot control device. Robot controller 12
Reference numerals a and 12b are respectively connected to and control the assembling robots and welding robots 14a and 14b which are working robots. The teaching device 10 includes a control circuit 16 that controls the entire teaching device 10.
Are a CRT 18 which is a display means for displaying a three-dimensional image of the robot, a keyboard 20 and a mouse 22 which are input means for giving various instructions, a floppy disk 24, a hard disk 26 and a magnetic tape reader 28 which are storage means. And a printer 30 or the like as an output means.

In FIG. 2, the control circuit 16 includes a CPU 3
2, an I / F 36 which is an interface circuit between the keyboard 20 and the mouse 22, and a welding robot 14
ROM 38 that stores work commands such as work position data, work conditions, and the like, and a control program.
A RAM 40 for temporarily storing a calculation result generated while the CPU 32 is executing the control program stored in the ROM 38, and a setting for setting a cycle time (working time) for each predetermined process of the welding robots 14a and 14b. A circuit 42 and a simulation circuit 44 for performing a simulation for each process of the welding robots 14a and 14b
And

The control circuit 16 further outputs a work time calculated and integrated by the CPU 32 during the teaching process, a comparison result obtained by comparing the work time with the set cycle time, a warning, and the like. , CR
An I / F 48 as an interface circuit connected to the T18 and the printer, and an I / F 50 as an interface circuit connected to the floppy disk 24, the hard disk 26 and the magnetic tape reader 28 are provided.

Here, in the teaching device 10,
The input / output device such as the hard disk 26, the output device such as the CRT 18, the RAM 40, and the CPU 32 have the functional blocks shown in the logical configuration diagram of FIG. That is, the input means such as the hard disk 26 includes a robot operation command input means 62 for inputting an operation command of the welding robots 14a and 14b, a robot target position input means 64 for inputting a movement target position of the welding robots 14a and 14b, and a welding robot 14a. , 1
4b, a robot operation condition input means 66 for inputting operation conditions and incidental conditions at each target position, the welding robot 1
It has a function such as a cycle time setting input means 68 for inputting a cycle time setting value or a cycle time setting permissible value for each of the steps 4a and 14b.

The CPU 32 controls the welding robot 14
robot posture calculating means 5 for calculating postures of a and 14b
2. Robot moving time calculating means 54 for calculating a moving time for the welding robots 14a and 14b to move to the target position with respect to the target position of each step of the welding robots 14a and 14b, and the welding robot 14a at each target position. ,
The robot working time calculating means 56 for calculating the working time of 14b, the integrating means 60 for integrating the moving time and the working time during a predetermined process, and the cycle time and the integrating means 60 calculated in advance for each process. It has functions such as a cycle time comparing means 70 for comparing the calculated working time and an image information creating means 58 for creating image information such as the attitude of the welding robots 14a and 14b from the calculation result of the robot attitude calculating means 52.

Further, output means such as the CRT 18 includes an image information output means 72 for outputting the image information, a cycle time output means 74 for outputting the calculated cycle time,
The RAM 40 has a function such as a cycle time over warning output unit 76 that outputs warning information when the calculated work time exceeds the set cycle time, and the RAM 40 stores a posture information of the welding robots 14a and 14b. It has functions such as an information storage unit 82 and an image information storage unit 84 for storing the image information.

In the teaching device 10 configured as described above, the operation and effect of calculating and evaluating the working time (operating time) of the welding robots 14a and 14b will be described with reference to FIG.
This will be described with reference to FIG.

A normal teaching operation is performed as follows. That is, the keyboard 2 is operated by the operator.
When a data reading instruction is input from the mouse 0 or the mouse 22 or the like, the CPU 32 determines the type and shape of the robot and the types of peripheral devices necessary for performing teaching.
Work environment data indicating the shape, operation performance data such as the number of axes of the robot arm, the length between the arm axes, and acceleration / deceleration data of the arm axes, target position (work position) coordinate data for each robot work process, and The attitude data of a tool such as a welding gun at each target position, welding condition (working condition) data such as welding gun energization time, and set cycle time data for each process are transmitted to the hard disk 2 via the I / F 50.
Read from 6. These data may be read from the floppy disk 24 or the magnetic tape reader 28.

Next, the position data of each axis is calculated for each unit movement distance of the robot according to the operation instruction of the operator input from the keyboard 20, and the robot posture calculating means 5
2 (see FIG. 1), the posture of the robot is calculated and stored in the robot posture information storage means 82. Image information is created by the image information creating means 58 based on the robot posture information, and stored in the image information storage means 84. The created image information is transmitted to the CRT 1 by the image information output means 72.
8 is displayed. The operator checks the interference between the work and the tool based on the image and corrects the necessary teaching data.

When such work is repeated for each work process of the robot and the teaching data is corrected,
By activating the simulation circuit 44, for example, a simulation of the welding robot 14a is performed, the teaching data and the actual operation of the robot are confirmed, the final teaching data is determined, and the teaching of the operation command of the robot controller 12a is completed. I do.

Here, the working process of the welding robot 14a is, for example, as shown in FIG.
Move from ₀ to a target position Q on the workpiece 11 such as a flange, perform welding work according to the work conditions specified at the target position Q, and then move to the target position R, and follow the work conditions specified at the target position R. perform welding operations, further movement to the target position S, perform welding operations according to specified operating conditions at the target position S, it is to return to the robot origin position P _0. Accordingly, as the teaching data, the position coordinates and the moving speed of the target positions Q, R, and S are given together with the movement command of the welding robot 14a. Welding conditions such as a hold command, an energizing time, and an open command are given.

In the process of off-line teaching using these teaching data, the working time in each step of the robot is calculated in accordance with the teaching data described above, and is compared with a preset cycle time for evaluation. In this evaluation, if the operation time of the robot calculated in the teaching process exceeds a preset cycle time, warning information is displayed, and the operator can correct the teaching data based on the warning.

That is, for example, according to the target position data and the moving speed parameter given to move the welding robot 14a to a desired target position (Q, R, S, etc. in FIG. 4), the robot moving time calculating means 54 The travel time required for the welding robot 14a to move to the target position is calculated, and the robot work time calculation means 56 performs the work of the welding robot 14a at each target position according to the work conditions instructing the work of the welding robot 14a at each target position. Time is calculated. The moving time and the working time for each target position are integrated by the integrating means 60 during a predetermined process, and the total working time (operating time) of the welding robot 14a in this process is calculated.

FIG. 5 shows a cycle time and a control circuit 1 set in advance for the operation of the welding robot 14a.
6 is a time chart showing a relationship with the work time calculated in FIG. 6, in which (a) shows a preset cycle time and (b) shows a calculated work time.

In FIG. 5A, CT ₁ , CT ₃ ,
CT _5, CT ₇ is the target position from the respective robot origin position P ₀ Q, the target position from the target position Q R, the target from the target position R position S, the welding from the target position S to the robot origin position P ₀ the robot 14a is moved Is the travel time required for
T ₂ , CT ₄ , and CT ₆ indicate the work time required for the welding robot 14a to work at the target positions Q, R, and S, respectively, and the set cycle time of this series of steps is the sum of these.

On the other hand, in FIG. 5B, ct ₁ , c
t ₃ , ct ₅ , and ct ₇ are movement times between the target positions Q, R, S, and the robot origin position P ₀ calculated by the robot movement time calculation means 54, respectively, and ct ₂ , ct ₄ ,
ct ₆ is the welding robot 1 at each of the target positions Q, R, and S calculated by the robot working time calculation means 56, respectively.
4a, and the work time (operating time) of this series of steps is the sum of these, and is calculated by the integrating means 60. In the teaching process, as shown by an arrow A in FIG. 5, when a delay occurs in the moving time calculated by the robot moving time calculating means 54 with respect to a preset cycle time, the integrating cycle 60 is added to the set cycle time.
Exceeds the work time calculated by The cycle time comparing means 70 includes a cycle time setting allowable value storage means 86
Is compared with the work time in real time, and when the work time is exceeded, a warning is output to the cycle time over warning output means 76. Therefore, it is easy to specify the location where the cycle time is over.

The set cycle time and the accumulated work time shown in FIG.
T18 is configured to be displayed on the individual travel time _{ct 1, ct 3, ct 5} , ct 7, working time c
When t ₂ , ct ₄ , and ct ₆ are calculated, they are displayed in real time as integrated values up to that time.

In the set cycle time and the work time shown in FIG. 5, if the work robot has an operation waiting time, the set values are compared taking the time into consideration.

Next, how the above processing is performed in the process of offline teaching will be described for a case where teaching is performed while revising teaching data that has been previously taught and a case where teaching is performed without revising. .

At the time of the teaching operation by the teaching device 10, when the posture data of the robot is revised or abolished, or when the revised posture data is stored as teaching data in the robot posture information storage means 82, the work process of the robot is started. From the current position to the current position (for new teaching without renovation), or
Calculate the working time from the start to the end of the working process (when teaching by changing and restructuring) as described above,
At the same time as outputting the renewed image information, the calculated work time is displayed on the CRT 18 by the cycle time output means 74. In this case, if the operation instruction is continuously given, the calculated work time is calculated in conjunction with the continuous operation of the welding robot 14a or every time the welding robot 14a is moved and its posture is stored as teaching data. Is updated and displayed.

Further, by setting a permissible cycle time in advance, when the calculated work time is out of the range of the permissible value, it is possible to warn the operator to that effect. For example, when teaching the welding robot 14a, the upper limit value of the cycle time which should not be exceeded is input and set from the keyboard 20, and stored in the cycle time setting allowable value storage means 86 (setting circuit 42) in the control circuit 16. The work time of the entire process calculated in accordance with the robot operation command from the mouse 22 is compared with the set allowable value of the cycle time set allowable value storage means 86. If the calculated work time is longer, the CRT 1
8, a message indicating that the cycle time is over can be displayed, and at the same time, a buzzer built in the CPU 32 can be sounded to warn the operator.

If there is a change in an element affecting the operation time, such as an environment setting relating to the operation speed of the welding robot 14a, a setting relating to the trajectory control, etc.
By inputting the changed condition from 0 to the control circuit 16, the result of the change can be reflected in the calculation and calculation of the working time.

FIG. 6 is a flowchart showing the above-described processing procedure when changing existing teaching data.
FIG. 7 is a transition diagram in the processing flowchart of FIG.

In step S1, the welding robot 14
The motion amount of each axis is calculated (state T3) from the posture data before the operation (a) (state T1 in FIG. 7), the input target position data, the operation command, etc. (state T2), and the posture data after the operation (state T3). The state T4) is calculated. Next, in step S2, the posture data after the operation (state T4), the posture data of the previous operation step (state T5), the posture data of the next operation step (state T6), and the posture after the operation. (State T7) and the amount of movement from the post-operation posture (state T7).
8) is calculated.

Next, in step S3, the movement time (section ct) to the post-operation posture (section ct) (state T9) and the movement time from the post-operation posture (state T10) are calculated.
4, the movement time up to the pre-operation posture (state T1
1) The movement time from the posture before operation (state T12), the total work time in the posture before operation (state T13), and the total work time after operation (state T14) are calculated.

The traveling time of the welding robot 14a (section c)
t) is calculated as follows. That is, FIG.
8B is a diagram showing the speed characteristics of the welding robot 14a. Here, a six-axis articulated robot is considered as an example. For each axis of the welding robot 14a, it is assumed that all six axes start to operate simultaneously at each teaching step and move at the same time at all axes simultaneously ending operation, and are completely housed in the posture stored in the teaching step. , The operation to the next step is started.

8A and 8B, the vertical axis represents speed.
v, the horizontal axis indicates time t, and each axis of the welding robot 14a
Maximum speed v₁, V_Two~ V₆And the maximum acceleration is a₁, A_Two
~ A ₆And the maximum deceleration is d₁, D_Two~ D₆And
Each axis of the bot has velocity characteristics (acceleration, constant
Speed, deceleration), but the movement distance between target positions is short
If the acceleration is not completed,
Speed characteristics as shown in Fig. 8B where
You.

A robot is moved between two positions (steps).
The travel distance of each axis is₁, P_Two~ P ₆And each
Required when the axis moves its maximum travel by itself
T₁, T_Two~ T₆At the start of the operation
When the time is set to 0, the change in velocity v with respect to time t for each axis is
f₁, F_Two~ F₆Then, the following equation is established.

[0044]

(Equation 1)

When this is solved for T _n , the following equation is obtained.

[0046]

(Equation 2)

[0047]

(Equation 3)

Here, the movement amount P and the movement time T (section c)
The relationship with t) is as shown in FIG. 8C. The equation (1) is shown in FIG.
A case where the welding robot 14a operates with the speed characteristic of A
Equation (2) shows a case where the welding robot 14a operates with the speed characteristics of FIG. 8B. In practice, the travel times T ₁ , T ₂ ~
To fit the largest axis in T _6, since the other axis is not operated at a reduced speed, the maximum value of the travel time of 6 axes, the travel time between the two positions (section ct) .

[0049]

In the method and apparatus for evaluating the operation time of a robot according to the present invention, the required time for each operation of the robot and the required time for one step of the operation are calculated and integrated.
Compared to the preset cycle time (working time),
Outputs (displays, etc.) in real time and issues a warning if the calculated work time exceeds the set cycle time, so the calculated cycle time (work time) exceeds the set cycle time. In this case, it is possible to correct the teaching data immediately so as to limit the portion that causes the excess and to settle within the set cycle time, and there is an effect that the teaching man-hour is not increased.

Further, the actual cycle time (work time) of the robot can be accurately matched with the preset cycle time, and the teaching work at the production site, and the effect of improving the production efficiency can be achieved. Furthermore, after one cycle of teaching is completed, it is not necessary to check the cycle time (work time) for the first time by performing a simulation, so that evaluation of robots and welding guns can be performed in real time, design changes and layout of the production process. When a situation such as a change or distribution of hit points occurs, the teaching can be easily repaired in response.

[Brief description of the drawings]

FIG. 1 is a logical configuration diagram of a control circuit in a teaching device embodying the present invention.

FIG. 2 is a block diagram showing a configuration of a control circuit in the teaching device.

FIG. 3 is a block diagram showing the overall configuration of the teaching device.

FIG. 4 is a conceptual diagram for explaining a work process of the robot.

FIG. 5 is a time chart showing a relationship between a set cycle time and a work time calculated by the teaching device.

FIG. 6 is a flowchart showing a work time calculation process by the teaching device.

FIG. 7 is a transition diagram showing states in the flowchart of FIG. 6;

8A and 8B show the speed characteristics of the robot, and FIG. 8C shows the relationship between the movement amount and the movement time of the robot.

[Explanation of symbols]

10 Teaching device 12a, 12b
... Robot control devices 14a, 14b ... Welding robot 16 ... Control circuit 18 ... CRT 20 ... Keyboard 22 ... Mouse 24 ... Floppy disk 26 ... Hard disk 28 ... Magnetic tape reader 30 ... Printer 32 ... CPU 54 ... Robot movement time calculation means 56 ... Robot work time calculation means 60 ... Accumulation means 62 ... Robot operation command input means 64 ... Robot target position input means 66 ... Robot work condition input means 68 ... Cycle time setting input means 70 ... Cycle time comparison means 74 ... Cycle time output means 76 ... Cycle time over warning output means

──────────────────────────────────────────────────続 き Continuation of the front page (72) Katsumi Takeishi Inventor 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (56) References JP-A-56-102495 (JP, A) JP-A-59 JP-140515 (JP, A) JP-A-5-309546 (JP, A) JP-A-60-61801 (JP, A) JP-A-2-53551 (JP, A) JP-A-57-205090 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G05B 19/4068

Claims (4)

(57) [Claims] 1. The teaching data of a robot is corrected.
Wherein a operation time evaluation method of the robot when, in accordance with parameters including the distance and velocity leading to the target position from the current position of the robot, the method comprising the robot calculates the moving time required to move to the target position Calculating a work time at the target position according to a work condition at the target position; and calculating an added value by adding the movement time and the work time.
A step of integrating the added value in a plurality of work steps to obtain an integrated value; and a step of setting the cycle time of the robot and the integrated value set in advance for the plurality of work steps in each of the work steps.
A step of comparing each processing; and a step of outputting warning information when the integrated value exceeds the cycle time and processing when the warning is output
A method for evaluating the operation time of a robot, comprising the steps of : 2. A method according to claim 1, wherein the step of calculating the operation waiting time of the robot including
Seen, the addition value, the operation time evaluation method of a robot and obtaining by adding the said the said travel time and the working time latency. 3. The teaching data of the robot is corrected.
Wherein a operation time evaluation apparatus for a robot in accordance with parameters including the distance and velocity leading to the target position from the current position of the robot travel time to the robot calculates the moving time required to move to the target position when A calculating means, a working time calculating means for calculating a working time at the target position according to a working condition at the target position, and an adding value by adding the moving time and the working time.
Integrating means for accumulating the added value in a plurality of operation steps, and a cycle time of the robot set in advance for the plurality of operation steps and an integrated value obtained by the accumulation means, for each of the operation steps. Comparing means for comparing each time of processing ; outputting warning information when the integrated value exceeds the cycle time; and processing when the warning is output
And an output unit for specifying the work process according to (1) . 4. A device according to claim 3, wherein the operation waiting time calculating means of the robot, the integration means, by being configured to calculate pressure and the and the moving time and the working time latency Characteristic robot operation time evaluation device.