CN116075402A - Robot control method and robot control device - Google Patents

Abstract

In the robot control method of the present disclosure, the positional deviation increment (Δθd- Δθ) is calculated based on the positional command increment (Δθd) and the positional increment (Δθ). The positional deviation (e) is calculated based on the positional deviation increment (Δθd- Δθ). The speed command (ωd) is calculated based on the position deviation (e) and the gain (K). The actuator 30 is driven by being supplied with a current (i) corresponding to the speed command (ωd). When an emergency stop command is output, the positional deviation increment (Δθd- Δθ) is multiplied by a predetermined coefficient (C) that becomes C > 1.0.

Description

Robot control method and robot control device

technical field

The present disclosure relates to a robot control method and a robot control device.

Background technique

Patent Document 1 discloses a numerical control device that switches from a normal gain to a higher gain calculated for emergency stop at the time of emergency stop, performs emergency stop by maintaining position control, and shortens the motor stop distance.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2016-082850

Contents of the invention

However, the numerical controller of Patent Document 1 is configured to shorten the stop time by increasing the gain of the position control at the time of emergency stop (emergency stop).

However, if the gain is increased, the speed command and the speed of the actuator may become unstable, and a shock may be generated in the actuator of each axis of the robot, the reducer, or the like.

An object of the present disclosure is to suppress the occurrence of an impact on an actuator during an emergency stop of a robot and shorten the stop time.

A first aspect of the present disclosure is a robot control method for controlling the motion of a robot having a plurality of actuators, the robot control method including: a first step of: Increment (Δθd) and the position increment (Δθ) fed back after the actuator is driven, calculate the position deviation increment (Δθd-Δθ); the second process, based on the position deviation increment (Δθd-Δθ) , calculate the position deviation (e); the third process, based on the position deviation (e) and the gain (K), calculate the speed command (ωd); the fourth process, the current corresponding to the speed command (ωd) ( i) supplying the actuator to drive the actuator; and a fifth step, when an emergency stop command is output during the repeated execution of the first step to the fourth step, The aforementioned positional deviation increment (Δθd-Δθ) is multiplied by a predetermined coefficient (C) such that C>1.0.

In the first aspect of the present disclosure, the position deviation increment (Δθd-Δθ) is calculated based on the position command increment (Δθd) and the position increment (Δθ). The positional deviation (e) is calculated based on the positional deviation increment (Δθd-Δθ). The speed command (ωd) is calculated based on the position deviation (e) and gain (K). The actuator is driven by being supplied with a current (i) corresponding to a speed command (ωd). When an emergency stop command is output, the positional deviation increment (Δθd-Δθ) is multiplied by a predetermined coefficient (C) such that C>1.0.

In this way, when the emergency stop command is output, the speed command (ωd) is increased by simply multiplying the position deviation increment (Δθd-Δθ) after the emergency stop command is output by the coefficient (C). Accordingly, it is possible to reduce the time until the actuator stops while suppressing the occurrence of a shock in the actuator.

A second aspect of the present disclosure is a robot control device including a control unit that controls the movement of a robot having a plurality of actuators, and the control unit operates as follows: The position command increment (Δθd) of the actuator and the position increment (Δθ) fed back after the actuator is driven are used to calculate the position deviation increment (Δθd-Δθ); the second action is based on the position deviation increment amount (Δθd-Δθ), calculate the position deviation (e); the third action, based on the position deviation (e) and gain (K), calculate the speed command (ωd); the fourth action, combine the speed command ( ωd) the corresponding current (i) is supplied to the actuator to drive the actuator; and the fifth action is to output an emergency stop command during the period of repeatedly performing the first action to the fourth action In the case of , the positional deviation increment (Δθd-Δθ) is multiplied by a predetermined coefficient (C) such that C>1.0.

In the second aspect of the present disclosure, the position deviation increment (Δθd-Δθ) is calculated based on the position command increment (Δθd) and the position increment (Δθ). The positional deviation ( ^e ) is calculated based on the positional deviation increment (Δθd-Δθ). The speed command (ωd) is calculated based on the position deviation (e) and gain (K). The actuator is driven by being supplied with a current (i) corresponding to a speed command (ωd). When an emergency stop command is output, the positional deviation increment (Δθd-Δθ) is multiplied by a predetermined coefficient (C) such that C>1.0.

In this way, when the emergency stop command is output, the speed command (ωd) is increased by simply multiplying the position deviation increment (Δθd-Δθ) after the emergency stop command is output by the coefficient (C). Accordingly, it is possible to reduce the time until the actuator stops while suppressing the occurrence of a shock in the actuator.

According to the present disclosure, at the time of emergency stop of the robot, it is possible to reduce the stop time while suppressing the shock from being generated in the actuator.

Description of drawings

FIG. 1 is a side view showing the configuration of a robot controller according to an embodiment of the present disclosure.

FIG. 2 is a block diagram of a robot controller according to an embodiment of the present disclosure.

FIG. 3 is a graph showing changes in speed when a gain is kept constant during an emergency stop in Comparative Example 1. FIG.

FIG. 4 is a graph showing changes in speed when the gain is increased during an emergency stop in Comparative Example 2. FIG.

FIG. 5 is a graph showing changes in speed when the coefficient is constant at the time of an emergency stop in the embodiment of the present disclosure.

FIG. 6 is a graph showing changes in speed when the coefficient is increased at the time of emergency stop in the embodiment of the present disclosure.

Detailed ways

Embodiments of the present disclosure will be described below based on the drawings. In addition, the description of the following preferred embodiments is merely an example in nature, and is not intended to limit the present disclosure, its application, or its use.

<Robot Structure>

FIG. 1 is a side view showing the configuration of a robot controller 1 according to an embodiment of the present disclosure. As shown in FIG. 1 , the robot control device 1 includes a robot 5 and a control unit 20 . The robot 5 has a 6-axis articulated robot arm 10 . The control unit 20 controls the operation of the robot arm 10 . The robot 5 delivers the workpiece W to the workbench 6, for example.

The robot arm 10 has a base portion 11 , a shoulder portion 12 , a lower arm portion 13 , a first upper arm portion 14 , a second upper arm portion 15 , a wrist portion 16 , and a mounting portion 17 .

The shoulder portion 12 is supported by the base portion 11 so as to be rotatable in the horizontal direction around the first joint portion J1. The lower arm portion 13 is supported by the shoulder portion 12 so as to be rotatable in the vertical direction around the second joint portion J2.

The first upper arm portion 14 is supported by the lower arm portion 13 so as to be rotatable in the vertical direction around the third joint portion J3. The second upper arm portion 15 is supported so as to be twistable and rotatable about the fourth joint portion J4 with respect to the front end portion of the first upper arm portion 14 .

The wrist portion 16 is supported by the second upper arm portion 15 so as to be rotatable in the vertical direction around the fifth joint portion J5. The attachment part 17 is supported by the wrist part 16 so that it can twist and rotate around the sixth joint part J6. A hand 18 for holding the workpiece W is attached to the mounting portion 17 .

Actuators 30 are built in the first joint J1 to the sixth joint J6 (see FIG. 2 ). The control unit 20 controls the driving of the actuators 30 of the first joint part J1 to the sixth joint part J6 so that the first joint part J1 to the sixth joint part J6 Reach the target position (command angle) respectively.

<control department>

FIG. 2 is a block diagram of the robot controller 1 . As shown in FIG. 2 , the control unit 20 has: a coefficient block 21 , an integral operator block 22 , a gain block 23 , and a speed and current control block 24 . The control unit 20 is connected to the actuator 30 of the robot 5 . Various sensors 31 are provided on the actuator 30 .

A position command increment (Δθd) for driving the actuator 30 and a position increment (Δθ) fed back after the actuator 30 is driven are input to the control unit 20 .

The control unit 20 performs a first operation of calculating a position deviation increment (Δθd−Δθ) based on the position command increment (Δθd) and the position increment (Δθ).

In the coefficient block 21, the positional deviation increment (Δθd-Δθ) is multiplied by a predetermined coefficient (C). During normal control, the coefficient (C) is set to C=1.0. In other words, during normal control, the coefficient (C) has no effect on the increase or decrease of the position deviation increment (Δθd-Δθ).

In the integrator block 22, the positional deviation increment (Δθd−Δθ) up to the present time is integrated. The control unit 20 performs the second operation of calculating the positional deviation (e) based on the positional deviation increment (Δθd−Δθ).

In the gain block 23, the positional deviation (e) is multiplied by the gain (K). The gain (K) is a coefficient for the response of the position control, and when the value of the gain (K) is increased, the responsiveness of the position control is improved. The control unit 20 performs a third operation of calculating the speed command (ωd) based on the positional deviation (e) and the gain (K).

Specifically, the speed command (ωd) is calculated based on the following equation.

[Formula 1]

Here, t is the current time, and te is the time when the emergency stop command was output. In addition, the operation of the control unit (20) when an emergency stop command is output will be described later.

A speed command (ωd), a current feedback signal (FB), and a speed feedback signal (FBω) are input to the speed and current control block 24 . The current feedback signal (FB) and the speed feedback signal (FBω) are fed back from various sensors 31 after the actuator 30 is driven.

In the speed and current control block 24, the current (i) corresponding to the speed command (ωd) is calculated. The control unit 20 performs a fourth operation of driving the actuator 30 by supplying the current (i) corresponding to the speed command (ωd) to the actuator 30 .

The actuator 30 is driven at a predetermined speed according to the supplied current (i). The control unit 20 controls the operation of the robot 5 by repeatedly executing the first operation to the fourth operation.

The control unit (20) multiplies the positional deviation increment (Δθd-Δθ) by a predetermined value when the emergency stop switch 8 is pressed or the like and an emergency stop command is output during the repeated execution of the first operation to the fourth operation. The 5th action of the coefficient (C). At the time of emergency stop, the coefficient (C) is set so that C>1.0. For example, the coefficient (C) is set to C=3.0.

However, when an emergency stop command is output, it is necessary to stop the operation of the actuator 30 urgently. However, if the time until the actuator 30 stops is shortened, for example, the gain (K) is increased, the speed command and the speed of the actuator 30 may become unstable, and the actuators 30 of each axis of the robot 5 may be unstable. shock.

Hereinafter, as Comparative Example 1, the change in the speed of the actuator 30 in the case where the gain (K) is constant at the time of emergency stop will be described. 3 is a graph showing changes in speed when a gain is kept constant during an emergency stop in Comparative Example 1. FIG.

As shown in Comparative Example 1 in Fig. 3, when the emergency stop command is output with the gain (K) constant, the speed command (ωd), position increment (Δθ), and actual speed (ω) gradually increase. reduce.

In Comparative Example 1 shown in FIG. 3, the value of the gain (K) is also constant at approximately 600 even after the emergency stop command is output. During normal control, the actuator 30 operating at a maximum speed of 4800 rpm is controlled so that the speed is 0 rpm during an emergency stop. Here, in the example shown in FIG. 3 , the time from when the emergency stop command is output until the speed reaches 0 rpm is 360 ms.

Next, as Comparative Example 2, a change in the speed of the actuator 30 when the gain (K) is increased at the time of emergency stop will be described. FIG. 4 is a graph showing changes in speed when the gain is increased during an emergency stop in Comparative Example 2. FIG.

In Comparative Example 2 in FIG. 4 , after the emergency stop command is output, the gain (K) is gradually increased. When an emergency stop command is output, the speed command (ωd), the position increment (Δθ), and the actual speed (ω) gradually decrease.

In Comparative Example 2 shown in FIG. 4 , the value of the gain (K) is approximately 600 during normal control, which is constant. During an emergency stop, the value of the gain (K) gradually increases and becomes constant at about 1100. In Comparative Example 2, the speed command (ωd) is calculated based on the following equation.

[Formula 2]

Here, ΔK is the gain increase amount.

In this way, in Comparative Example 2 of FIG. 4 , when calculating the speed command (ωd), the entire position deviation increment (Δθd-Δθ) is multiplied by the gain increase amount (ΔK), so the responsiveness of the position control is improved. Therefore, in Comparative Example 2, the time from when the emergency stop command is output until the speed reaches 0 rpm is 277 ms, and the time until the actuator 30 stops can be shortened compared to Comparative Example 1 in which the gain (K) is kept constant.

However, if the value of the gain (K) is too high, the operation becomes unstable. Specifically, in Comparative Example 2 in FIG. 4 , immediately after the emergency stop command is output, a shock occurs in the actuator 30 , and the actuator 30 becomes an unstable operation such that the speed of the actuator 30 rises further than the maximum speed.

On the other hand, in the present embodiment, by studying the operation of the control unit (20) after the emergency stop command is output, the occurrence of a shock in the actuator 30 is suppressed.

First, as shown in FIG. 5 , a case where the coefficient (C) is set to C=1.0 will be described. FIG. 5 is a graph showing changes in speed when a coefficient is kept constant at the time of an emergency stop in the embodiment of the present disclosure.

In the example shown in FIG. 5 , when the emergency stop command is output, the speed command (ωd), the position increment (Δθ), and the actual speed (ω) gradually decrease.

In the example shown in FIG. 5, the coefficient (C) is also constant at C=1.0 even after the emergency stop command is output. During normal control, the actuator 30 operating at a maximum speed of 4800 rpm is controlled so that the speed is 0 rpm during an emergency stop. Here, in the example shown in FIG. 5 , the time from when the emergency stop command is output until the speed reaches 0 rpm is 356 ms.

Next, a change in the speed of the actuator 30 when the coefficient (C) is increased at the time of emergency stop will be described. 6 is a graph showing changes in speed when the coefficient is increased at the time of emergency stop in the embodiment of the present disclosure.

As shown in FIG. 6, after the emergency stop command is output, the coefficient (C) is set to be larger than 1.0 (C>1.0). In the example shown in FIG. 6, C=3.0 is set. Then, as shown in the above-mentioned formula 1, the speed command (ωd) is increased only by multiplying the position deviation increment (Δθd-Δθ) after the emergency stop command is output by the coefficient (C).

Therefore, in the present embodiment, the time from when the emergency stop command is output until the speed reaches 0 rpm is 258 ms, which can be shortened until the actuator 30 stops when compared with the case where the coefficient (C) is constant at C=1.0. time so far.

In addition, in the example shown in FIG. 6 , it can be seen that the speed of the actuator 30 decreases smoothly without causing a shock to the actuator 30 even after the emergency stop command is output.

As described above, in the robot controller 1 according to the present embodiment, when the emergency stop command is output, only the position deviation increment (Δθd-Δθ) after the emergency stop command is output is multiplied by C> A coefficient (C) of 1.0 is used to increase the speed command (ωd). Accordingly, it is possible to suppress the occurrence of a shock in the actuator 30 and shorten the time until the actuator 30 stops.

Industrial availability

As described above, the present disclosure can obtain the highly practical effect of suppressing the shock generated by the actuator during an emergency stop, and thus is extremely useful and has high industrial applicability.

-Symbol Description-

1 Robot controller

5 robots

8 Emergency stop switch

10 robotic arms

11 base part

12 shoulders

13 lower arm

14 1st upper arm

15 2nd upper arm

16 Wrist

17 Installation Department

18 hands

20 Control Department

21 coefficient blocks

22 integral operator block

23 gain block

24 Current control block

30 actuator

31 various sensors

J1 Joint #1

J2 Joint #2

J3 Joint 3

J4 Joint 4

J5 Joint 5

J6 Joint 6

W Workpiece.

Claims (2)

1. A robot control method for controlling an operation of a robot having a plurality of actuators, the robot control method comprising:

a 1 st step of calculating a positional deviation increment (Δθd- Δθ) based on a positional command increment (Δθd) for driving the actuator and a positional increment (Δθ) fed back after driving the actuator;

step 2, calculating a position deviation (e) based on the position deviation increment (delta theta d-delta theta);

a step 3 of calculating a speed command (ωd) based on the positional deviation (e) and the gain (K);

a 4 th step of supplying a current (i) corresponding to the speed command (ωd) to the actuator to drive the actuator; and

and a 5 th step of multiplying the positional deviation increment (Δθd- Δθ) by a predetermined coefficient C that is C > 1.0 when an emergency stop command is output while repeating the 1 st step to the 4 th step.

2. A robot control device is provided with a control unit for controlling the operation of a robot having a plurality of actuators,

the control unit performs the following operations:

1 st operation of calculating a positional deviation increment (Δθd- Δθ) based on a positional command increment (Δθd) for driving the actuator and a positional increment (Δθ) fed back after driving the actuator;

2 nd operation of calculating a positional deviation (e) based on the positional deviation increment (Δθd- Δθ);

a 3 rd operation of calculating a speed command (ωd) based on the position deviation (e) and the gain (K);

a 4 th operation of supplying a current (i) corresponding to the speed command (ωd) to the actuator to drive the actuator; and

and an operation 5 in which, while repeating the operations 1 to 4, when an emergency stop command is output, the positional deviation increment (Δθd- Δ0) is multiplied by a predetermined coefficient C that is C > 1.0.

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