JP2020023013A - Robot control method - Google Patents

Abstract

To perform appropriate acceleration/deceleration processing according to use or work content of a robot.SOLUTION: It is selected that acceleration/deceleration processing of a machining robot 1 is to be performed either by acceleration/deceleration processing before interpolation or by acceleration/deceleration processing after interpolation. When the acceleration/deceleration processing before interpolation is selected, the acceleration/deceleration processing before interpolation is performed to position data before acceleration/deceleration of the machining robot 1, and a displacement magnitude of a motor 21 is calculated on the basis of the position data after the acceleration/deceleration processing. On the other hand, when the acceleration/deceleration processing after interpolation is selected, the displacement magnitude of the motor 21 is calculated on the basis of the position data before the acceleration/deceleration of the machining robot 1.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a robot control method.

  Due to its structure, the robot generates vibrations when suddenly accelerating or suddenly decelerating, which may cause a reduction in machining accuracy or damage to the driving unit. Therefore, usually, acceleration adjustment processing called acceleration / deceleration processing is performed. Thus, the command value of the movement amount given to the robot is gradually changed to suppress the vibration.

  Usually, the acceleration / deceleration processing is realized by a method of smoothing the movement amount of each motor constituting the robot (acceleration / deceleration after interpolation). However, when this method is used, the start point and the end point of the movement section are determined. Although the position is guaranteed, an error occurs in the middle trajectory. This is because the actual motor angle changes to an angle different from the ideal angle due to the smoothing.

  Therefore, there is an acceleration / deceleration method (acceleration / deceleration before interpolation) for smoothing the amount of change in the position of the motion trajectory in the rectangular coordinate system instead of smoothing the movement amount of each motor (for example, Patent Document 1). According to this method, acceleration and deceleration are performed along an ideal motion trajectory, so that not only the start point and the end point of the moving section but also the middle trajectory can be operated without error.

Japanese Patent No. 6100816

  By the way, in the pre-interpolation acceleration / deceleration, the motor may perform an excessive operation to follow an ideal motion trajectory depending on the posture and the moving speed of the robot, and the motor cannot be used in every case. .

  The present invention has been made in view of such a point, and an object of the present invention is to enable appropriate acceleration / deceleration processing to be performed according to the use of a robot and the contents of work.

  The present invention is directed to a robot control method for controlling the operation of a machining robot having a plurality of joints, and has taken the following solution.

That is, the first invention selects whether the acceleration / deceleration processing of the machining robot is performed by acceleration / deceleration before interpolation or acceleration / deceleration after interpolation.
Calculating a displacement of a motor that drives the joint based on the position data of the machining robot,
In the step of calculating the displacement amount of the motor, when the pre-interpolation acceleration / deceleration processing is selected, the pre-interpolation acceleration / deceleration processing is performed on the position data of the machining robot before the acceleration / deceleration, and after the acceleration / deceleration processing While calculating the displacement amount of the motor based on the position data, when the acceleration / deceleration processing after interpolation is selected, the displacement amount of the motor is calculated based on the position data of the machining robot before acceleration / deceleration. It is characterized in that it is calculated.

  In the first invention, it is selected whether to perform acceleration / deceleration processing of the machining robot by acceleration / deceleration before interpolation or acceleration / deceleration after interpolation. In the pre-interpolation acceleration / deceleration, acceleration / deceleration is performed along an ideal motion trajectory, so that not only the start point and the end point of the moving section but also the middle trajectory can be operated without error. Therefore, it may be selected when high processing accuracy is required.

  On the other hand, in the post-interpolation acceleration / deceleration, the positions of the start point and the end point of the moving section are guaranteed, but errors occur in the trajectory in the middle. I just need.

  When the pre-interpolation acceleration / deceleration processing is selected, the pre-interpolation acceleration / deceleration processing is performed on the position data of the machining robot before the acceleration / deceleration, and the displacement of the motor is calculated based on the position data after the acceleration / deceleration. You. On the other hand, if the post-interpolation acceleration / deceleration process is selected, the displacement of the motor is calculated based on the position data before the acceleration / deceleration.

  Accordingly, an appropriate motion trajectory can be realized by selectively switching between the acceleration / deceleration before interpolation and the acceleration / deceleration after interpolation according to the use or the work content of the robot.

  For example, in construction requiring accuracy such as laser welding, acceleration / deceleration processing before interpolation can be performed to switch to high-precision operation, and higher-quality processing can be performed. In addition, when the robot is moved to the next welding point, since high-precision operation is not required, the acceleration / deceleration processing after interpolation may be performed.

In a second aspect, in the first aspect,
When the workpiece to be machined by the machining robot is movably held by the workpiece movable unit, the pre-interpolation acceleration / deceleration process or the post-interpolation acceleration / deceleration process is performed on the position data of the workpiece movable unit before the acceleration / deceleration. Steps to perform;
Calculating the position data of the machining robot before the acceleration / deceleration based on the position data after the acceleration / deceleration of the work movable part.

  In the second invention, when the work is held movably by the work movable section, the pre-interpolation acceleration / deceleration processing or the post-interpolation acceleration / deceleration processing is performed on the position data before the acceleration / deceleration of the work movable section. ing. Then, the position data of the machining robot before the acceleration / deceleration is calculated based on the position data of the work movable part after the acceleration / deceleration.

  Thus, the position data of the machining robot can be generated in consideration of the acceleration / deceleration of the movable part of the work.

A third invention is a method according to the first or second invention,
Reducing the at least one of the processing speed and the processing acceleration of the processing robot when the displacement of the motor is larger than a predetermined threshold value.

  In the third aspect, when the displacement amount of the motor is larger than the predetermined threshold, that is, when the acceleration of the motor is too large, there is a possibility that vibration may be caused by sudden acceleration or sudden deceleration of the motor. Therefore, the processing speed and processing acceleration of the processing robot are reduced to suppress the motor acceleration.

A fourth invention is the third invention, wherein
After reducing at least one of the processing speed and the processing acceleration of the processing robot, re-calculating the displacement of the motor,
A step of further reducing at least one of the processing speed and the processing acceleration of the processing robot when the displacement amount of the motor after the recalculation is larger than the threshold value.

  In the fourth invention, when the displacement of the motor recalculated after reducing the processing speed of the processing robot is larger than a threshold value, the processing speed and the processing acceleration are further reduced. That is, the calculation is repeatedly performed until the acceleration of the motor becomes appropriate, thereby limiting the acceleration of the motor that causes vibration.

According to a fifth aspect, in the fourth aspect,
If the displacement amount of the motor after repeating the step of reducing at least one of the processing speed and the processing acceleration a predetermined number of times is larger than the threshold value, the acceleration / deceleration processing of the processing robot is performed by interpolation acceleration / deceleration. It is characterized by performing.

  In the fifth invention, even if the reduction of the processing speed and the processing acceleration are repeated a predetermined number of times, if the displacement of the motor is larger than the threshold value, the acceleration / deceleration processing of the processing robot is performed by the acceleration / deceleration after interpolation. I have. In other words, it is determined that vibrations caused by sudden acceleration or deceleration of the motor during acceleration / deceleration before interpolation cannot be sufficiently suppressed, and priority is given to suppressing vibration rather than high-precision operation. A deceleration process is performed.

  According to the present invention, it is possible to perform appropriate acceleration / deceleration processing in accordance with the use of the robot and the work content.

It is a side view showing the composition of the processing robot concerning this embodiment. FIG. 2 is a block diagram illustrating a configuration of a processing robot. FIG. 3 is a diagram illustrating an operation trajectory of a processing robot with respect to a work. FIG. 9 is a diagram for describing processing performed by acceleration / deceleration after interpolation. FIG. 4 is a diagram for explaining processing performed in acceleration / deceleration before interpolation. FIG. 4 is a block diagram illustrating a configuration of a work movable unit. It is a flowchart figure which shows the operation | movement procedure of the robot for processing. It is a flowchart figure which shows the operation | movement procedure of the robot for processing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely an example in nature, and is not intended to limit the present invention, its application, or its use.

  As shown in FIG. 1, the processing robot 1 includes a six-axis articulated robot arm 10. A robot controller 30 that controls the operation of the robot arm 10 is connected to the processing robot 1. In the example illustrated in FIG. 1, the processing robot 1 performs processing on a workpiece W fixed to a work table 25 installed on the ground. Note that the number of joints of the processing robot 1 and a horizontal articulated type, a vertical articulated type, and the like may be freely selected.

  The robot arm 10 includes a pedestal portion 11, a shoulder portion 12 supported by the pedestal portion 11 so as to be pivotable in the horizontal direction around the first joint portion J <b> 1, and a vertical direction around the second joint portion J <b> 2 on the shoulder portion 12. Lower arm 13 rotatably supported on the first arm, first upper arm 14 supported on lower arm 13 so as to be rotatable up and down around third joint J3, and first upper arm The second upper arm 15 is supported at the tip of the first joint 14 so as to be rotatable around the fourth joint J4, and the second upper arm 15 can pivot vertically about the fifth joint J5. And a mounting portion 17 supported by the wrist 16 so as to be rotatable around the sixth joint J6. A welding torch 18 is attached to the attachment portion 17. Note that a laser cutting head may be attached.

  A motor 21 (see FIG. 2) is built in the first to sixth joints J1 to J6. The robot control device 30 controls the first joint J1 to the sixth joint J6 based on an operation program input in advance by teaching or the like so that each of the first joint J1 to the sixth joint J6 reaches the target position (command angle). The drive of the motor 21 of the six joints J6 is controlled.

  As shown in FIG. 2, a robot controller 30 that controls the operation of the motor 21 is connected to the processing robot 1. The robot control device 30 includes an input unit 31, a current control unit 32, a storage unit 34, and a control unit 35.

  In the machining robot 1, the encoder detects the position of the rotor of the motor 21 at a predetermined sampling cycle. The position information of the motor 21 is transmitted to the control unit 35.

  The input unit 31 inputs an operation program for controlling the operation of the processing robot 1. The operation program input by the input unit 31 is transmitted to the control unit 35 and stored in the storage unit 34.

  The torque command value and the motor generated torque are input from the control unit 35 to the current control unit 32. The current control unit 32 calculates a drive command value, and supplies a current to the motor 21 based on the drive command value. Thus, the current control unit 32 controls the driving of the motor 21.

  The control unit 35 includes a calculation unit 36 and a selection unit 37. The calculation unit 36 performs various calculations based on the input information. For example, the calculation unit 36 calculates the dynamic torque based on the position information of the motor 21, the information on the speed and the acceleration, and the like. The torque calculated by the calculation unit 36 is transmitted to the storage unit 34 and stored. The calculation unit 36 performs acceleration / deceleration processing before interpolation and acceleration / deceleration processing after interpolation to be described later.

  The selection unit 37 selects whether to perform acceleration / deceleration processing of the machining robot 1 by acceleration / deceleration before interpolation or acceleration / deceleration after interpolation. Here, whether to select the acceleration / deceleration before interpolation or the acceleration / deceleration after interpolation is described by the user as a parameter in the operation program of the machining robot 1. For example, in a section where precise processing is required, a command set to acceleration / deceleration before interpolation, otherwise, a command set to acceleration / deceleration after interpolation is described in the operation program.

  The operation program input to the input unit 31 is read by the control unit 35, and the selection unit 37 selects whether to use the acceleration / deceleration before interpolation or the acceleration / deceleration after interpolation.

  Here, the acceleration / deceleration after the interpolation is a method of smoothing the moving amount of the motor 21 constituting the robot arm 10. In the post-interpolation acceleration / deceleration, the positions of the start point and the end point of the moving section are guaranteed, but an error occurs in the middle trajectory. I just need.

  On the other hand, the acceleration / deceleration before interpolation is an acceleration / deceleration method for smoothing the amount of change in the position of the motion trajectory in the rectangular coordinate system. In addition, in the pre-interpolation acceleration / deceleration, acceleration / deceleration is performed along an ideal motion trajectory, so that not only the start point and the end point of the moving section but also the middle trajectory can be operated without error. Therefore, it may be selected when high processing accuracy is required.

  Specifically, as shown in FIG. 3, a process of performing C-shaped laser welding at a plurality of locations using the processing robot 1 will be examined. At this time, the processing accuracy is required at a portion welded in a C-shape, and in this section, it is appropriate to perform acceleration / deceleration before interpolation. On the other hand, the section moving from the C-shaped welding point to the adjacent C-shaped welding point is an idle running section, and therefore it is appropriate to perform acceleration and deceleration after interpolation. Hereinafter, specific processing contents of the acceleration / deceleration after interpolation and the acceleration / deceleration before interpolation will be described.

<Acceleration / deceleration after interpolation>
As shown in FIG. 4, in the post-interpolation acceleration / deceleration, the following first to fifth processes are sequentially performed. In the first process, a point on the trajectory of the moving section in which the machining robot 1 operates is calculated by interpolation. That is, the operation start point S is connected to the operation end point E, and the section is finely divided into a plurality (X1 to X6 in FIG. 4). As a result, the position components (X, Y, Z, U, V, W) of the machining robot 1 in the orthogonal coordinate system are obtained for each division point. Here, X, Y, and Z indicate the positions of the processing points, and U, V, and W indicate the attitude (angle) of the welding torch 18.

  In the second process, the position data of the machining robot 1 in the orthogonal coordinate system is converted into angles (RT, UA, FA, RW, BW, TW) of the motor 21 by inverse kinematics calculation. In addition, RT, UA, FA, RW, BW, and TW indicate the angles of the motor 21 of the first joint J1 to the sixth joint J6, respectively.

  In the third process, the amount of angular displacement (△ RT, △ UA, △ FA, △ RW, △ BW, △ TW) of the motor 21 required in each divided section is calculated. Depending on the attitude of the processing robot 1, the motor angle at which the angular velocity needs to be rapidly accelerated / decelerated may be calculated in the second processing. In the example illustrated in FIG. 4, the displacement amount of any one of the motors 21 of the first to sixth joints J1 to J6 is illustrated.

  In the fourth process, smoothing is performed by filtering the displacement amount of the motor 21. That is, since sudden acceleration and sudden deceleration cause the machining robot 1 to vibrate, filter processing is performed so that sudden acceleration and sudden deceleration become slow acceleration and slow deceleration.

  Here, the filter determines a speed change waveform during acceleration / deceleration, and is generally a moving average filter that realizes trapezoidal acceleration / deceleration, or a two-stage movement that implements S-curve acceleration / deceleration. An average filter is used.

  In the fifth process, the filtered displacement of the motor 21 is obtained. Since the filtered angle change amount of the motor 21 is smoothed, the change in the angular velocity becomes gentle. This completes the post-interpolation acceleration / deceleration processing.

  By the way, the post-interpolation acceleration / deceleration processing may deviate from an ideal trajectory in order to forcibly reduce the angle change amount of the motor 21 required to realize a desired trajectory. Therefore, in order to operate not only the start point and the end point of the moving section but also the middle trajectory without errors, the acceleration / deceleration before interpolation may be performed.

<Acceleration / deceleration before interpolation>
As shown in FIG. 5, in the acceleration / deceleration before interpolation, the following first to fifth processes are sequentially performed. In the first process, a point on the trajectory of the movement section in which the machining robot 1 operates is calculated by interpolation. That is, the operation start point S is connected to the operation end point E, and the section is finely divided into a plurality of sections (X1 to X6 in FIG. 5). Thereby, the position components (X, Y, Z, U, V, W) of the machining robot 1 in the orthogonal coordinate system are obtained for each division point. Here, X, Y, and Z indicate the positions of the processing points, and U, V, and W indicate the attitude (angle) of the welding torch 18.

  In the second process, the movement amount in the orthogonal coordinate system between the division points of the processing robot 1 is calculated. Note that, unlike the acceleration / deceleration after interpolation, the angle of the motor 21 is not calculated.

  In the third process, smoothing is performed by filtering the amount of movement between the division points in the orthogonal coordinate system.

  In the fourth process, the filtered movement amount in the rectangular coordinate system is obtained. Since the movement amount in the filtered rectangular coordinate system is smoothed, the speed change of the movement amount along the trajectory becomes gentle.

  In the fifth process, the angle (RT, UA, FA, RW, BW, TW) of the motor 21 is calculated by inverse kinematics calculation based on the movement amount obtained in the fourth process. This completes the pre-interpolation acceleration / deceleration processing. Note that RT, UA, FA, RW, BW, and TW indicate the angles of the motor 21 of the first joint J1 to the sixth joint J6, respectively.

  In the pre-interpolation acceleration / deceleration process, the angle of the motor 21 is calculated after acceleration / deceleration is performed on the trajectory. Therefore, the operation of the machining robot 1 is positioned on the trajectory even during acceleration / deceleration.

  However, in the pre-interpolation acceleration / deceleration processing, when the angle of the motor 21 is calculated by the inverse kinematics calculation in the fifth processing, the angle change of the motor 21 becomes excessively large in order to follow an ideal motion trajectory. There is.

  Therefore, in the present embodiment, the acceleration and deceleration before interpolation and the acceleration and deceleration after interpolation are selectively switched according to the use and the work content of the machining robot 1.

  The work W may be installed not only in a form in which the work W is held on the work table 25 fixed on the ground (see FIG. 1), but also in a form in which the work W is movably held using the work movable unit 26. (See FIG. 6).

  As shown in FIG. 6, the work movable section 26 has a motor 27, and is composed of, for example, a positioner (external shaft) or another handling robot. Since the work movable section 26 also needs acceleration / deceleration processing, similarly to the processing robot 1, the reference coordinate system is also accelerated / decelerated. This causes a locus error, which causes deterioration of the processing quality. Therefore, when the workpiece W is held so as to be movable, the position data of the machining robot 1 before the acceleration / deceleration is changed in consideration of the acceleration / deceleration of the workpiece movable unit 26.

<Switching procedure between acceleration / deceleration before interpolation and acceleration / deceleration after interpolation>
As shown in FIG. 7, first, in step S101, an ideal motion trajectory of the machining robot 1 in the reference coordinate system where the workpiece W is set is created. Here, "ideal" refers to an ideal state in which the component does not perform any acceleration / deceleration and instantaneously reaches the commanded speed, and is also referred to as position data before acceleration / deceleration.

  In step S102, it is determined whether or not the processing of the processing robot 1 is performed with high accuracy. If the determination in step S102 is "YES", the flow branches to step S103 to perform acceleration / deceleration before interpolation. If the determination in step S102 is "NO", acceleration / deceleration is performed after interpolation. If the post-interpolation acceleration / deceleration process is selected, an inverse kinematics operation is performed on the position data of the machining robot 1 before the acceleration / deceleration to calculate the displacement amount of the motor 21.

  In step S103, it is determined whether the work W is to be movable. That is, it is determined whether the work W is held on the work table 25 installed on the ground or whether the work W is movably held by the work movable unit 26. If the determination in step S103 is "YES", the flow branches to step S104. If the determination in step S103 is "NO", the flow branches to step S107.

  In step S104, post-interpolation acceleration / deceleration processing is performed on the position data of the work movable unit 26 before acceleration / deceleration. Here, the reason why the post-interpolation acceleration / deceleration is used as the acceleration / deceleration processing is that the error caused by the post-interpolation acceleration / deceleration of the work movable unit 26 can be absorbed by the trajectory on the machining robot 1 side. Acceleration / deceleration processing is performed. However, in some cases, the pre-interpolation acceleration / deceleration processing may be performed.

  In step S105, angle data (position data) after acceleration / deceleration of the work movable section 26 is created.

  In step S106, based on the ideal work reference position data of the machining robot 1 and the position data of the work movable part 26 after acceleration / deceleration, the position data of the robot coordinate reference before acceleration / deceleration of the machining robot 1 is calculated. calculate. Thus, the position data of the machining robot 1 can be generated in consideration of the acceleration / deceleration of the work movable unit 26.

  In step S107, the pre-interpolation acceleration / deceleration processing is performed on the robot coordinate reference position data before the acceleration / deceleration of the machining robot 1. In other words, the acceleration / deceleration before interpolation is performed with respect to the trajectory of the tool tip position based on the coordinate system on which the work W is installed, that is, the relative position between the work W and the tool tip.

  In step S108, an inverse kinematics calculation is performed on the position data of the machining robot 1 after the acceleration / deceleration processing after the interpolation acceleration / deceleration processing, and the displacement amount of each motor 21 is calculated.

  Next, as shown in FIG. 8, in step S109, it is determined whether the acceleration of each motor 21 of the processing robot 1 is appropriate, that is, whether the displacement of the motor 21 is equal to or less than a predetermined threshold. That is, the acceleration that causes a shock or vibration is limited.

  If the determination in step S109 is "YES", it is determined that the acceleration of each motor 21 of the processing robot 1 is appropriate, and the flow branches to step S118. If the determination in step S109 is "NO", it is determined that the allowable acceleration of the motor is exceeded, and the flow branches to step S110. The threshold value for determining whether the motor 21 is appropriate is determined by the specifications of the motor 21 and the designation of the user.

  In step S110, it is determined whether the processing acceleration of the processing robot 1 can be reduced. If the determination in step S110 is "YES", the flow branches to step S111. If the determination in step S110 is "NO", the flow branches to step S112.

  In step S111, the acceleration of the motor 21 is suppressed by reducing the processing acceleration of the processing robot 1, and the process proceeds to step S114.

  In step S112, it is determined whether the processing speed of the processing robot 1 can be reduced. If the determination in step S112 is "YES", the flow branches to step S113. If the determination in step S112 is "NO", the flow branches to step S117.

  In step S113, the acceleration of the motor 21 is suppressed by reducing the processing speed of the processing robot 1, and the process proceeds to step S114.

  Since changing the processing speed or processing acceleration of the processing robot 1 affects the processing result, whether to permit the processing for reducing the processing speed or processing acceleration is left to the user's settings.

  In step S114, after reducing the processing speed and processing acceleration of the processing robot 1, the displacement of the motor 21 is recalculated.

  In step S115, it is determined whether the displacement of the motor 21 after the recalculation is equal to or smaller than the threshold, that is, whether the acceleration of the motor 21 is appropriate, that is, whether the displacement of the motor 21 is equal to or smaller than a predetermined threshold. . If the determination in step S115 is "YES", it is determined that the acceleration of the motor 21 has become appropriate, and the flow branches to step S118. If the determination in step S115 is "NO", the flow branches to step S116.

  In step S116, it is determined whether the number of repetitions of the step of reducing the processing speed and the processing acceleration of the processing robot 1 is equal to or less than a predetermined number. If the determination in step S116 is "YES", the flow returns to step S110, and adjustment is performed so as to further reduce the processing speed and the processing acceleration. If the determination in step S116 is "NO", the flow branches to step S117. Since changing the processing speed or processing acceleration of the processing robot 1 affects the processing result, the number of repetitions is left to the user's setting.

  In step S117, it is determined whether the machining robot 1 can operate in the acceleration / deceleration processing after interpolation. If the determination in step S117 is "YES", the post-interpolation acceleration / deceleration processing is performed on the machining robot 1. That is, even if the machining speed and machining acceleration of the machining robot 1 are repeatedly reduced a predetermined number of times, if the displacement amount of the motor 21 is larger than the threshold value, the acceleration or deceleration of the motor 21 in the acceleration / deceleration before interpolation is reduced. Since it is determined that the accompanying vibration cannot be sufficiently suppressed, acceleration / deceleration processing after interpolation is performed with priority given to suppressing vibration rather than performing high-precision operation.

  If the determination in step S117 is "NO", it is determined that execution is not possible, and an error or the like is issued.

  In step S118, since the acceleration and speed of each motor 21 are within the appropriate range, the displacement amount of each motor 21 is instructed to the working robot 1 and the work movable unit 26, which are constituent elements, to operate. The process ends.

  As described above, the present invention has a highly practical effect that it can perform appropriate acceleration / deceleration processing in accordance with the purpose and work content of a robot, and is therefore extremely useful and industrially applicable. Is expensive.

DESCRIPTION OF SYMBOLS 1 Processing robot 10 Robot arm 21 Motor 26 Work movable part 30 Robot controller 35 Control part 36 Operation part 37 Selection part J1-J6 Joint part

Claims (5)

A robot control method for controlling an operation of a processing robot having a plurality of joints,
A step of selecting whether to perform acceleration / deceleration processing of the machining robot by acceleration / deceleration before interpolation or acceleration / deceleration after interpolation;
Calculating a displacement of a motor that drives the joint based on the position data of the machining robot,
In the step of calculating the amount of displacement of the motor, when the pre-interpolation acceleration / deceleration processing is selected, the pre-interpolation acceleration / deceleration processing is performed on the position data of the machining robot before the acceleration / deceleration, and after the acceleration / deceleration processing While the displacement amount of the motor is calculated based on the position data, when the post-interpolation acceleration / deceleration process is selected, the displacement amount of the motor is calculated based on the position data of the machining robot before acceleration / deceleration. A robot control method characterized by calculating. In claim 1,
When a workpiece to be processed by the processing robot is movably held by a workpiece movable unit, the pre-interpolation acceleration / deceleration processing or the post-interpolation acceleration / deceleration processing is performed on the position data of the workpiece movable unit before acceleration / deceleration. Steps to perform;
Calculating the position data of the machining robot before the acceleration / deceleration based on the position data after the acceleration / deceleration of the work movable part. In claim 1 or 2,
A step of reducing at least one of a processing speed and a processing acceleration of the processing robot when a displacement amount of the motor is larger than a predetermined threshold value. In claim 3,
After reducing at least one of the processing speed and the processing acceleration of the processing robot, re-calculating the displacement of the motor,
A step of further reducing at least one of the processing speed and the processing acceleration of the processing robot when the displacement amount of the motor after the recalculation is larger than the threshold value. In claim 4,
If the displacement amount of the motor after repeating the step of reducing at least one of the processing speed and the processing acceleration a predetermined number of times is larger than the threshold value, the acceleration / deceleration processing of the processing robot is performed by interpolation acceleration / deceleration. A robot control method characterized by performing.

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