JP2023174158A - robot system - Google Patents

Abstract

To provide a robot system which can control a robot to a safety side to the extent possible, even where an operation state of the robot cannot be predicted.SOLUTION: A robot system 1 includes: an RC 3 for controlling operation of a robot 2 by using a control program; and an SMM 4 for monitoring control contents according to the RC 3 while communicating with the RC 3. The RC 3 transmits, to the SMM 4, a normal request for switching when executing a CS command in the control program. When reaching a situation of not being able to predict an operational state of the robot 2, the RC 3 transmits, to the SMM 4, a request for switching to a default scene. Upon reception of the normal switching request, the SMM 4 performs switching of a limit value of a parameter according to the CS command, meanwhile, upon reception of the request for switching to the default scene, switches to a limit value of a parameter of the default scene.SELECTED DRAWING: Figure 8

Description

TECHNICAL FIELD The present invention relates to a system for improving safety.

How to improve safety when operating robots is always an issue. Here, the following method is assumed as one of the means to ensure safety. A controller that controls the motion of a robot handles motion speed, output torque, etc. as control-related parameters. In the control program, when the scene or situation in which the robot works, that is, the scene changes, commands are used to change parameter data, such as maximum speed and maximum torque, that define the robot's operation. For example, for scenes where there is a possibility that people may approach, the above values are set relatively low. In this way, the maximum value of the control parameter is set according to the robot's operation scene, and the control parameter is monitored so that it does not exceed the maximum value in each scene. Note that Patent Document 1 shows an example of an industrial robot to which a safety system is applied.

JP 2017-24095 Publication

Assuming the above method, the program creator needs to predict the operating state of the robot to some extent and determine parameter values for each scene. However, when the robot starts up or when an abnormality occurs, it is difficult to predict the operating state of the robot.

The present invention has been made in view of the above circumstances, and its purpose is to provide a robot system that can control a robot as safely as possible even when the operating state of the robot cannot be predicted.

According to the robot system according to the first aspect, in order to limit the motion of the robot, limit values are defined for parameters related to the control of the motion. When the state of the robot controlled by the control unit executing the control program reaches a specific condition for which no limit value is defined, the limit value is switched to a predetermined limit value corresponding to the specific condition. That is, when the control state of the robot reaches a specific condition for which a limit value is not defined, the limit value is automatically switched to a predetermined limit value corresponding to the specific condition. This allows the robot's operation to be controlled as safely as possible even under specific conditions.

According to the robot system according to the second aspect of the present invention, the control program includes a plurality of normal switching commands used to switch the limit value according to the situation in which the robot is operated. The control unit issues a safety setting switching request when the robot is controlled based on the control program and the operating state corresponding to the specific condition becomes unpredictable. At least some of the limit values corresponding to the safety setting switching request are set to values smaller than the limit values of each parameter corresponding to the normal switching command. In this way, by setting the limit value corresponding to the specific condition to a smaller value than the limit value corresponding to the normal switching command, the operation of the robot can be reliably controlled on the safe side.

Here, the situation in which the operating state of the robot cannot be predicted is, for example, when a control program starts to be executed as in the robot system according to claim 3, or when an abnormality occurs as in the robot system according to claim 4. This is when the execution of the control program is stopped. Specifically, under these situations, the robot can be controlled as safely as possible.

According to the robot system according to the fifth aspect, the switching permission conditions corresponding to each normal switching command are registered in advance in the determination section. Further, the limit values of each parameter corresponding to the safety setting switching request are registered as a safety setting parameter group. When the control unit executes the normal switching command in the control program, the control unit transmits the normal switching request together with the corresponding switching permission condition to the determination unit. Upon receiving the normal switching request, the determining unit compares the permission condition corresponding to the normal switching command with the corresponding permission condition registered in advance to determine permission or disapproval, and transmits the determination result to the control unit. Further, upon receiving the safety setting switching request, the determination unit transmits a default setting command for switching to the limit value of the parameter of the safety setting parameter group to the control unit.

With this configuration, the determination unit independent of the control unit can switch parameters corresponding to normal and safety setting switching requests, so the control unit only responds to normal switching requests and safety setting switching requests. All you have to do is send it to the judgment section.

Specifically, as in the robot system according to claims 6 to 8, when the power is turned on (claim 6), the determination unit finishes execution of the first control program after the power is turned on. After that (Claim 7), when there is a notification from the control unit indicating that execution of the control program has started (Claim 8), a default setting command is transmitted to the control unit. As described above, in response to situations in which the operating state of the robot is unpredictable, the control unit can be caused to switch to the limit values of the parameters of the safety setting parameter group.

According to the robot system according to claim 9, upon receiving the safety setting switching request, the determining unit determines the limit value of the parameter of the safety setting parameter group and the limit value of the corresponding parameter in the operation of the robot at that time. When compared, if the former limit value is smaller, the default setting command is not sent to the control unit. In other words, if the limit value of the corresponding parameter in the actual operation of the robot is smaller than the limit value of the safety setting parameter group, data with a smaller value that is safer is selected.

The first embodiment is a diagram showing the configuration of a robot system. Diagram showing the maximum values of parameters according to each scene Diagram showing how to set parameter values according to each scene from a personal computer to the safety motion module Sequence diagram showing the processing performed between the robot controller and safety motion module during a normal switching request Diagram showing the default scene added to Figure 2 Sequence diagram showing when power is applied to SMM Flowchart showing determination process (1) performed by SMM Sequence diagram showing the processing performed between RC and SMM when the program starts Sequence diagram showing the processing performed between RC and SMM when a program is stopped due to an abnormality occurrence A flowchart showing the determination process (2) according to the second embodiment, which corresponds to the case where the robot's current parameter value is smaller than the maximum value of the default scene.

(First embodiment)
The first embodiment will be described below with reference to the drawings. As shown in FIG. 1, the robot system 1 of this embodiment includes a robot 2 having, for example, a vertical six-axis arm, a robot controller that controls the operation of the robot 2 according to a control program; It is equipped with a motion module; SMM4. The robot 2, RC3, and SMM4 communicate with each other by wire or wirelessly. RC3 corresponds to a control section, and SMM4 corresponds to a determination section.

Furthermore, in this embodiment, a command called a change scene command is written in the control program. Hereinafter, this will be referred to as a "CS command." The CS command, which corresponds to the switching command, sends data on parameters such as speed and torque that define the movement of the robot 2 when the scene or situation in which the robot 2 works, that is, the scene changes, in the situation where the robot 2 is operated. This is the command to change.

For example, as shown in Figure 2, the scenes in which the robot 2 works are numbered like 1, 2, 3, etc., and the maximum allowable speed [mm/s] and output torque are determined for each scene number. Switch the values of parameters such as [N] using the CS command. For example, for scenes where there is a possibility that people may approach, the above values are set relatively low. Furthermore, the CS command is given the position coordinates (x, y, z) of the hand of the robot 2 as a condition for allowing the command to switch the allowable values of each parameter.

Data values of parameters and permission conditions corresponding to each CS command are written by the creator in a personal computer; PC5, as shown in FIG. 3, for example. Then, data values such as parameters of each command are sent to the SMM 4 and registered. The data value of the parameter corresponds to a limit value.

Next, the operation of this embodiment will be explained. For example, assume that in a control program, a CS command "changeScene2" is written following the command "Move P0", and a command "Move P1" is written after that. Furthermore, if the command "Move P0" is executed in scene 1, then scene 1 is switched to scene 2 by executing the above CS command.

As shown in FIG. 4, for example, when executing "changeScene2", the RC3 transmits a request to switch to scene 2 to the SMM4. Then, the SMM 4 determines whether the control state of the robot 2 at that time satisfies the conditions for permitting switching of the changeScene 2. If the permission conditions are met, the SMM 4 transmits an approval signal to the RC 3, and in response to this, the RC 3 switches the parameters, operating speed output torque, and maximum value of the movable range according to changeScene 2. The above switching request corresponds to a normal switching request. The SMM 4 monitors the control parameter values in each scene so that they do not exceed the maximum values set by the CS command while the RC 3 is controlling the robot 2. Below, the above maximum value is also referred to as a "monitoring value."

Furthermore, in this embodiment, a default scene is used separately from scenes 1 to 3. As shown in an example in Figure 5, the maximum speed and maximum torque values set as the default scene are set to values smaller than the values set in other scenes 1 to 3, and are applied to robot 2. It is used to make the settings more secure when For example, the parameter values of the default scene shown in FIG. 5 are set as a maximum speed of 20 [mm/S] and a maximum torque of 20 [N]. Regarding the movable range, since it is not possible to know where the hand position of the robot 2 is at that time, the setting is such that the movable range is allowed up to the maximum value MAX without setting a limit. These default scene monitoring values are an example of a safety setting parameter group.

The default scene is applied when it is determined in RC3 or SMM4 that the operating state of the robot 2 is in an unpredictable situation, and there are multiple cases as follows.
<When powering on SMM4>
As shown in FIG. 6, when the power is turned on, the SMM 4 executes the determination process (1) shown in FIG. First, the SMM 4 determines whether or not its own mode is a mode that can be automatically started (S1), and if it is a mode that is possible (Yes), it applies the monitoring value of the default scene (S2). On the other hand, if the mode is not possible (No), for example, a monitoring value for teaching is applied (S3). The "monitored value for teaching" is, for example, the maximum speed in manual operation defined by the standard. Then, as shown in FIG. 6, the SMM 4 transmits a signal to the RC 3 approving the switching to the respective monitored values.

<When starting the program>
As shown in FIG. 8, for example, when a button displayed on the display screen is operated or a request to start a control program is input to RC3 via I/0 or PC5, RC3 performs program execution processing. When starting, a request to change the default scene is sent to SMM4. This change request is sent from the base system that executes the control program. The SMM 4 transmits a signal approving switching to the RC 3 in order to apply the data of each parameter of the default scene as a monitoring value. Then, RC3 starts executing the user program after applying the monitoring value of the default scene. A request to change to the default scene corresponds to a request to switch to the safe side. Note that the user program is the same as the control program.

<When the program stops due to an error occurrence>
As shown in FIG. 9, even when some abnormality occurs while RC3 is executing the user program and RC3 stops executing the user program and stops the robot 2, the default scene is displayed in SMM4. Submit a change request to. Then, SMM4 transmits a signal approving the switching to RC3, similar to the case shown in FIG.

As described above, according to the present embodiment, the robot system 1 includes the RC 3 that controls the operation of the robot 2 using a control program, and the SMM 4 that communicates with the RC 3 and monitors the content of control by the RC 3. The control program describes a plurality of CS commands used to switch the parameter data related to the control of the motion according to the situation in which the robot 2 is operated. Data and permission conditions for each parameter corresponding to a plurality of CS commands are registered in advance in the SMM 4. In addition, in SMM4, data values of at least some of the parameters corresponding to multiple CS commands are set to values smaller than data values of corresponding parameters in multiple CS commands. A group of default scene parameters is also registered in advance.

RC3 sends a normal switching request to SMM4 when executing a CS command in the control program. When the operating state of the robot 2 becomes unpredictable, the RC3 transmits a request to switch to the default scene to the SMM4. Upon receiving the normal switching request, the SMM 4 transmits a signal approving the switching if the control state of the robot 2 at that time satisfies the switching permission conditions. Further, upon receiving a request to switch to the default scene, it transmits a signal approving switching to the monitored value of the parameters of the default scene.

With this configuration, in a situation where the operating state of the robot 2 is unpredictable, for example, when the execution of a program is started, or when the execution of a control program is stopped due to the occurrence of an abnormality, monitoring values of parameters corresponding to multiple CS commands can be used. Since the monitoring value of the default scene is set to a small value, the robot 2 can be controlled as safely as possible.

The SMM4, which is independent from the RC3, can determine whether or not to cause the RC3 to switch monitoring values of parameters corresponding to the CS command or default scene based on the permission conditions, thereby further improving safety. can.
Further, when the SMM 4 is powered on, it also transmits a signal approving switching of the default scene parameters to the monitored values. That is, even immediately after the RC3 is powered on and started, the RC3 is in a situation where the operating state of the robot 2 cannot be predicted, so the data value of the default scene is set in this case as well.

(Second embodiment)
Hereinafter, parts that are the same as those in the first embodiment are given the same reference numerals and explanations will be omitted, and different parts will be explained. In the second embodiment, when the SMM 4 receives a request to change the default scene, it compares the monitoring value of the default scene with the data value of the corresponding parameter of the robot 2 at that time.

For example, as shown in FIG. 10 as determination process (2), if the current speed of robot 2 is slower than the maximum speed of the default scene (S11; Yes), the current speed of robot 2 is not changed (S12 ). Further, if the current torque of the robot 2 is smaller than the maximum torque of the default scene (S13; Yes), the current torque of the robot 2 is not changed (S14). That is, in this case, no switching approval signal is sent to RC3.

If the maximum speed of the default scene is less than the current speed of robot 2 (S11; No), the maximum speed of the default scene is applied (S15), and the maximum torque of the default scene is smaller than the current torque of robot 2. In that case (S13; No), the maximum torque of the default scene is applied (S16).

As described above, according to the second embodiment, when the SMM 4 receives a request to change the default scene, the SMM 4 determines the monitoring value of the parameter of the default scene and the monitoring value of the corresponding parameter in the movement of the robot 2 at that time. compare. If the former monitored value is smaller, the latter monitored value is not changed. In other words, if the monitored value of the corresponding parameter in the actual operation of the robot 2 is smaller than the monitored value of the safety setting parameter group, a smaller monitored value that provides greater safety is selected.

It is also possible to apply the maximum speed and maximum torque of the default scene in steps S12 and S14 as well. In this way, it can be said that by unifying the monitoring values of the default scene to be applied in all cases, it becomes easier for the person monitoring the operation of the robot 2 to grasp the control state.

The present invention is not limited to the embodiments described above or illustrated in the drawings, but can be modified or expanded as described below.
The parameter values of the default scene may be applied whenever the power is turned on without making the determination in step S1.
The parameters specified by the CS command are not limited to operating speed and output torque.
The robot is not limited to the vertical 6-axis type.

Instead of registering the monitored values of each parameter in the SMM 4 in advance, the monitored values of each parameter may be written in the CS command, and these monitored values may be passed to the SMM 4 when making a scene switching request.
Although functions in text programming are used to change scenes, changes may also be made by substituting variables or arranging blocks in visual programming.

The data values of parameters and permission conditions corresponding to each CS command do not necessarily need to be registered in the SMM 4, and may be registered in a storage that can be accessed by both the RC 3 and the SMM 4, for example.

In the case shown in FIG. 6, instead of using the power ON as the trigger, the SMM 4 may be caused to execute the determination process (1) using the start of execution of the control program as the trigger.
Furthermore, in a case where a plurality of control programs are executed continuously, when the execution of one control program is completed, the SMM 4 may be caused to execute the determination process (1) before starting execution of the next control program.

In the drawings, 1 is a robot system, 2 is a robot, 3 is a robot controller, and 4 is a safety motion module.

Claims (9)

Equipped with a control unit that controls the operation of the robot using a control program,
In order to limit the movement of the robot, limit values are defined for parameters related to the control of the movement,
When the robot is controlled based on the control program under a specific condition in which the limit value is not defined, the robot system switches the limit value to a predetermined limit value corresponding to the specific condition. The control program describes a plurality of normal switching commands used to switch the limit value according to a situation in which the robot is operated,
The control unit issues a safety setting switching request when the robot is controlled based on the control program and the operating state of the robot becomes unpredictable as the specific condition;
2. The robot system according to claim 1, wherein at least some of the limit values corresponding to the safety setting switching request are set to values smaller than limit values of each parameter corresponding to the normal switching command. 3. The robot system according to claim 1, wherein the situation in which the operating state of the robot is unpredictable is when execution of the control program starts. 3. The robot system according to claim 1, wherein the situation in which the operating state of the robot cannot be predicted is when execution of the control program is stopped due to occurrence of an abnormality. comprising a determination unit that determines whether or not switching of the limit value is permitted;
In the determination unit, switching permission conditions corresponding to each normal switching command are registered in advance,
The limit values of each parameter corresponding to the safety setting switching request are registered as a safety setting parameter group,
When executing the normal switching command in the control program, the control unit transmits a normal switching request together with a corresponding switching permission condition to the determination unit,
When the determination unit receives the normal switching request, the determination unit compares the permission condition corresponding to the normal switching command with the corresponding permission condition registered in advance to make the permission/disapproval determination, and transmits the determination result to the control unit. and send it to
3. The robot system according to claim 2, wherein upon receiving the safety setting switching request, a default setting command for switching to a limit value of a parameter of the safety setting parameter group is sent to the control unit. The robot system according to claim 5, wherein the determination unit transmits the default setting command to the control unit when the power is turned on. 7. The robot system according to claim 6, wherein the determination unit transmits the default setting command to the control unit after execution of the first control program is completed after power is turned on. 6. The robot system according to claim 5, wherein the determination section transmits the default setting command to the control section upon receiving a notification from the control section indicating that execution of the control program has started. Upon receiving the safety setting switching request, the determination unit compares the limit value of the parameter of the safety setting parameter group with the limit value of the corresponding parameter in the operation of the robot at that time, and determines that the former limit value is The robot system according to any one of claims 5 to 8, wherein if the default setting command is smaller than that, the default setting command is not transmitted to the control unit.

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