Robot Control System

Abstract

To suitably improve safety and working efficiency of a robot.SOLUTION: A robot 20 is movable between a processing area E2 and an accumulation area E3 provided in one section of a factory 10. The robot 20 moved to the processing area E2 performs work for taking out workpiece from a processing machine 14 arranged in the processing area E2, and storing it in a container 18. After collection of the workpiece has been completed, the robot 20 conveys the workpiece to the accumulation area E3 through a passage E4 together with a container 18. After moved to the accumulation area E3, the robot 20 stacks the container 18 on a pallet 15. A control device of the robot 20 identifies a work scene of the robot from a progress status of an operation program. The control device switches a determination reference for monitoring operation of the robot 20 according to the identified work scene.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a robot control system. [Background technology]

[0002] Some robot control systems applied to robots such as industrial robots have a safety-related part that realizes the safety functions of the robot, and a non-safety-related part that controls the drive of the robot, etc. As for the safety-related part, there have been proposals for a system that forcibly stops the robot when it collides with an obstacle such as a person (see, for example, Patent Document 1), or forcibly stops the robot when it monitors the force (thrust) and speed of the robot while it is moving and the movement deviates from the safety standards. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4240517 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the types of work that a robot can perform are also increasing due to the advancement of robot technology. When a robot is used for various tasks, it may be difficult to improve both safety and work efficiency if the safety functions are uniform. In view of this situation, the inventor of the present invention has devised a configuration for switching the safety functions of a robot. However, if the safety functions are frequently switched, the control load in the robot control system increases excessively, and it is assumed that the impact on the original function of the robot control system (i.e., the function of executing the drive control of the robot) will be large. For example, if the safety functions are changed sequentially in response to changes in the position or orientation of the robot, the above-mentioned impact will be significant. Such an impact is undesirable because it is a factor that leads to a decrease in the work efficiency of the robot. In addition, it is undesirable that the switching operation of the safety functions by the user is required, as it is a factor that reduces the convenience of the robot. Thus, in order to realize an improvement in the safety and workability of the robot and promote the use of the robot, there is still room for improvement in the configuration related to the change of the safety functions.

[0005] The present invention has been made in consideration of the above problems, and a main object of the present invention is to preferably improve the safety and working efficiency of a robot. [Means for solving the problem]

[0006] Means for solving the above problems will be described below.

[0007] First means: A robot control system having a safety-related unit that has a motion judgment unit that judges the motion of the robot based on a safety-related input signal including a parameter correlated with at least one of the force and speed of the robot during work and a judgment criterion for the parameter that is stored in advance, and that realizes a safety function of the robot by generating a safety-related output signal according to the judgment result, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; A plurality of work scenes in which the robot performs different tasks are defined as work scenes in which the robot performs tasks; a storage unit that stores the parameter judgment criteria in association with each of the work scenes; a scene classification unit for classifying a work scene of the robot; a criterion switching unit for switching a criterion for the parameters referred to by the action determination unit to a criterion corresponding to the work scene identified by the scene identification unit; It is equipped with:

[0008] It is preferable for a single robot to be able to handle multiple different tasks in order to promote the automation of manufacturing and other processes. However, if the safety functions of a robot are made uniform regardless of the work scene, it becomes difficult to improve both safety and work efficiency. In this regard, the configuration shown in this feature identifies the work scene and changes the monitoring criteria for each work scene. This contributes to improving the safety of the robot and improving work efficiency.

[0009] Here, in order to improve the safety of the robot, it is possible to configure the safety functions to change sequentially every time the operating state (position, orientation, speed, etc.) of the robot changes. However, such a configuration increases the control load on the robot control system, affecting the original function of the robot control system (robot drive control). In this regard, considering that the movement of the robot changes for each task, there is a clear technical significance in configuring the system to switch the judgment criteria for each task scene, as shown in this feature, in that it can improve safety while minimizing the impact on the original function of the robot control system.

[0010] Second means: A robot control system having a safety-related unit that has a motion judgment unit that judges the motion of the robot based on a safety-related input signal including a parameter correlated with at least one of the force and speed of the robot during work and a judgment criterion for the parameter that is stored in advance, and that realizes a safety function of the robot by generating a safety-related output signal according to the judgment result, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; A work area is defined for each work to be performed by the robot; a storage unit that stores the parameter judgment criteria in association with each of the work areas; an area identification unit for identifying a working area of ​​the robot; a criterion switching unit for switching a criterion for the parameter referred to by the operation judging unit to a criterion corresponding to the work area identified by the area identifying unit; It is equipped with:

[0011] According to the configuration shown in the second aspect, the work area is identified and the monitoring criteria are changed for each work area. This contributes to improving the safety of the robot and the work efficiency. Moreover, this configuration has a clear technical significance in that it can improve safety while suppressing the impact on the original functions of the robot control system, compared to a configuration in which the safety function is changed sequentially according to the change in the position or orientation of the robot.

[0012] Third means: A robot control system provided with a safety-related unit that has a motion judgment unit that judges the motion of the robot based on a safety-related input signal including a parameter correlated with at least one of the force and speed of the robot during work and a judgment criterion for the parameter that is stored in advance, and that realizes a safety function of the robot by generating a safety-related output signal according to the judgment result, a drive control unit that controls the robot to operate according to a predetermined time schedule in accordance with a set operation program; The predetermined time schedule specifies that a plurality of types of work are to be performed in sequence according to time or time of day, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; a storage unit that stores a judgment criterion for the parameter in association with the time or the time instant; A grasping unit that grasps the current time or the hour; a criterion switching unit that switches a criterion for the parameter referred to by the operation judging unit to a criterion corresponding to the predetermined time or the predetermined hour when the time or the hour grasped by the grasping unit becomes a predetermined time or a predetermined hour for moving to a next task in the predetermined time schedule; It is equipped with:

[0013] According to the configuration shown in the third aspect, the current time (for example, the elapsed time from the start of the work routine) or the time is grasped, and when a predetermined time or a predetermined time is reached, the monitoring judgment criteria is changed. This can contribute to improving the safety of the robot and the work efficiency. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a schematic diagram showing a part of a layout of a factory in the first embodiment. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a block diagram showing the electrical configuration of the robot. [Figure 4] 1 is a flowchart showing the flow of work by a robot. [Diagram 5] Schematic diagrams comparing robot working scenes. [Figure 6] FIG. 2 is a schematic diagram showing the relationship between safety-related parts and non-safety-related parts. [Figure 7] 13 is a flowchart showing an operation monitoring process. [Figure 8] FIG. 13 is a schematic diagram illustrating a control device that instructs switching of safety functions. [Figure 9] 13 is a flowchart showing a task monitoring process. [Figure 10] FIG. 4 is a schematic diagram showing a request command transmitted from a non-safety-related part. [Figure 11] FIG. 1 is a schematic diagram showing the flow of a scene change sequence. [Figure 12] A schematic diagram comparing the criteria for each scene. [Figure 13] FIG. 1 is a schematic diagram for explaining a problem. [Figure 14] 10 is a flowchart showing a scene change monitoring process in the second embodiment. [Figure 15] 6 is a timing chart showing a change in a detection value when a work scene is changed. [Figure 16] 13 is a flowchart showing a scene change monitoring process in the third embodiment. [Figure 17] 6 is a timing chart showing a change in a detection value when a work scene is changed. [Figure 18] FIG. 13 is a schematic diagram showing an object detection region in the fourth embodiment. [Figure 19] 13 is a flowchart showing a special switching monitoring process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <First embodiment> Hereinafter, a first embodiment of the present invention will be described with reference to the drawings, in which the present invention is embodied in an industrial robot for use in factories, etc. First, with reference to FIG.

[0016] In one section of the factory 10, there are provided a stock area E1 in which shelves 12 for storing materials transported by a conveyor 11 and shelves 13 for storing empty containers (so-called returnable boxes) 18 are arranged, a processing area E2 in which a plurality of processing machines 14 for forming workpieces are arranged, an accumulation area E3 in which the formed workpieces are accumulated, and an aisle E4 connecting these areas E1 to E3. The robot 20 shown in this embodiment moves between the areas E1 to E3 through the aisle E4 and engages in the work assigned to each area.

[0017] As shown in FIG. 2, the robot 20 includes an AGV (Automated Guided Vehicle) 31, a vertical articulated robot arm 41 mounted on the AGV 31, and a control device 50 (see FIG. 3) that controls the AGV 31 and the robot arm 41.

[0018] The AGV 31 is provided with a travel motor 35 and a magnetic sensor 36 capable of detecting magnetism of a guide tape for magnetic guidance laid on the floor of the factory 10, and the control device 50 performs travel control of the AGV 31, such as drive control and steering control of the travel motor 35, based on the magnetism detected by the magnetic sensor 36. In this embodiment, guide tapes are placed in the areas E1 to E3 and the passage E4 so as to connect the areas E1 to E3, and the movement path (travel route) of the robot 20 is defined by the guide tapes.

[0019] A placement section 32 on which the container 18 is placed is formed on the upper surface of the body of the AGV 31, and the AGV 31 can move with the container 18 placed on the placement section 32. The AGV 31 is also provided with a laser scanner 37 for detecting obstacles on the path of the robot 20 and an emergency stop switch 38 that is operated by an operator or the like in an emergency. The laser scanner 37 and the emergency stop switch 38 function as input sections for a safety-related section, which will be described later, and are configured to bring the robot 20 to an emergency stop when an obstacle is detected or an emergency stop operation is detected. In this emergency stop, not only the AGV 31 but also the robot arm 41 are subject to stopping.

[0020] The robot arm 41 has a base fixed to the upper surface of the body of the AGV 31 (next to the placement unit 32), an arm attached to the base, and a hand 42 (end effector) provided at the tip (hand tip) of the arm. The arm is formed by connecting a plurality of movable parts, and a drive motor 45 for driving the movable parts, a rotary encoder 46 for detecting the rotation angle of each joint part (axis), and a torque sensor 47 for detecting the rotation torque of each joint part (axis) are provided for each joint part (see FIG. 3). As shown in FIG. 3, the drive motor 45, the rotary encoder 46, and the torque sensor 47 are connected to a control device 50, and a drive control unit 51 of the control device 50 controls the drive of each drive motor 45 based on the rotation angle detected by the rotary encoder 46, etc.

[0021] A teaching pendant 60 can be connected to the control device 50 via a communication cable. A setting support application is installed on the teaching pendant 60, and supports the user in setting the movement of the robot 20 (including so-called teaching). The teaching pendant 60 transmits an operation sequence indicating the movement of the robot 20 set by the user to the control device 50, and a drive control unit 51 of the control device 50 controls the drive of the AGV 31 and the robot arm 41 based on this operation sequence. Hereinafter, the work handled by the robot 20 will be described with reference to Figs. 1 and 4.

[0022] First, the robot 20 sets an empty container 18 on itself in the stock area E1 (scene SN1). Specifically, the robot arm 41 is extended to grab an empty container 18 stored on the shelf 13, and the container 18 is placed on its placement section 32. Thereafter, the robot arm 41 is returned to the standby position, and moves to the processing area E2 through the passage E4 (scene SN2). Note that the robot arm 41 in the standby position is prevented from protruding from the AGV 31 when the robot 20 is viewed from above.

[0023] In the processing area E2, the completed workpieces are collected from the multiple processing machines 14 arranged in the processing area E2 (scene SN3). Specifically, the robot arm 41 is extended to grab the workpiece held in the chuck of the processing machine 14 with the hand 42, and the workpiece is removed and stored in the set container 18. This movement is repeated for each processing machine 14, and collection is completed when the number of collected workpieces reaches a predetermined number. After collection is completed, the robot arm 41 is returned to the standby position, and the container 18 containing the workpieces is transported to the accumulation area E3 through the passage E4 (scene SN4).

[0024] In the accumulation area E3, the containers 18 containing the workpieces are unloaded. Specifically, the containers 18 are stacked on the pallets 15 (scene SN5). The group of containers 18 stacked on the pallets 15 is transported sequentially to the next process (e.g., another processing process).

[0025] In the above scene SN3, the workpieces are stored in the container 18 in an aligned state, but if the workpieces pile up in the container 18 for some reason, they may interfere with the stacking of the container 18. Therefore, in the above scene SN4, the robot arm 41 performs an operation to change the position of the workpieces in the container 18 as necessary. This change operation is performed in parallel with the transportation.

[0026] After completing unloading in the accumulation area E3, the robot 20 returns the robot arm 41 to the standby position and moves from the accumulation area E3 to the end of the conveyor 11 through the passage E4 (scene SN6). Then, the robot 20 receives the container 18 containing the work material from the conveyor 11 (scene SN7). Specifically, the container 18 is set on the placement section 32 by a crane attached to the conveyor 11. When receiving the container 18, the robot arm 41 temporarily changes direction to avoid colliding with the container 18.

[0027] The robot 20 on which the container 18 has been set transports the container 18 through the passage E4 to the stock area E1 (scene SN8). After arriving at the stock area E1, the robot 20 stores the set container 18 on the shelf 12 (scene SN9).

[0028] After the storage is completed, the series of operations in scenes SN1 to SN9 are repeated again. In this manner, in this embodiment, the work routine of the robot 20 is constructed by scenes SN1 to SN9. Note that, depending on the operation status of the conveyor 11, scenes SN7 to SN9 are skipped.

[0029] Scenes SN1 to SN9 differ not only in the area where the robot 20 is located and the specific content of the work, but also in the relationship with people (whether or not there is collaboration, etc.). Some scenes in the work routine, specifically scenes SN3 to SN5, will be described below with reference to Fig. 5. For convenience, in the following description, "scene" will also be referred to as "work scene".

[0030] The processing area E2 where the work (picking) of scene SN3 is performed is a collaboration area where an area staff (human) works together with the robot 20. Specifically, the area staff of the processing area E2 are responsible for the tasks of taking out materials from the containers 18 stored on the shelves 12 and feeding them into the processing machines 14, setting up each processing machine 14, and checking the operation of each processing machine 14, while the robot 20 is responsible for the collection task of collecting the processed workpieces. In other words, in the processing area E2, both the area staff and the robot 20 share the work related to the processing machines 14.

[0031] For the work (transport) in scene SN4, the work area is defined as the aisle E4, and for the work (palletizing) in scene SN5, the work area is defined as the accumulation area E3. The work in scenes SN4 and SN5 differs from scene SN3 in that the robot 20 performs the work alone (non-collaborative work). However, while people (such as area personnel) are allowed to pass through the aisle E4, people are basically prohibited from entering scene SN5. In other words, there is a difference in the possibility of contact between the robot 20 and people between scenes SN4 and SN5 due to the difference in the operation of the areas. Specifically, the possibility of contact between people and the robot 20 is higher in scene SN4 than in scene SN5.

[0032] As described above, the robot 20 may come into contact with humans during its work routine, and is provided with configurations for enhancing the safety of the robot 20 in addition to the laser scanner 37 and emergency stop switch 38. Below, a supplementary explanation of the configuration related to the safety functions of the robot 20 will be given with reference to FIG.

[0033] The robot control system CS applied to the robot 20 is classified into a safety-related part X that realizes the safety function of the robot 20 by outputting a safety-related output signal in response to a safety-related input signal, and a non-safety-related part Y that controls the drive of the AGV 31 and the robot arm 41 when safety has been confirmed by the safety-related part X and the operation of the AGV 31 and the robot arm 41 is permitted.

[0034] The safety-related part X is composed of an input part X1 that inputs the above-mentioned safety-related input signal, a logic part X2 that performs safety checks, and an output part X3 that outputs a safety-related output signal. In this embodiment, the laser scanner 37, the emergency stop switch 38, etc. correspond to the input part X1, a monitoring control part (safety controller) 52 provided in the control device 50 corresponds to the logic part X2, and a safety contactor attached to the control device 50 corresponds to the output part X3.

[0035] The safety contactor is connected to a switch provided in a drive circuit for the travel motor 35 of the AGV 31 and a switch provided in a drive circuit for the drive motor 45 of the robot arm 41. When a safety-related output signal is output from the safety contactor to these switches, the power supply to each of the motors 35, 45 is cut off, and the robot 20 is forcibly stopped.

[0036] The safety-related unit X shown in this embodiment includes the rotary encoder 46 and the torque sensor 47 in addition to the laser scanner 37 and the emergency stop switch 38. That is, the detection signal from the rotary encoder 46 and the detection signal from the torque sensor 47 are input to the logic unit X2 as the safety-related input signals. The logic unit X2 monitors the operation of the robot 20 based on the detection signals from the rotary encoder 46 and the torque sensor 47. Here, the operation monitoring process executed as part of the regular processing by the logic unit X2 (the monitoring control unit 52 of the control device 50) will be described with reference to the flowchart of FIG.

[0037] In the operation monitoring process, first, in step S101, operation monitoring parameters such as the force (thrust), speed, and position (coordinates) of the tip of the robot 20 (robot arm 41) (so-called tool center point) are identified based on the detection signals from the rotary encoder 46 and the torque sensor 47.

[0038] In the next step S102, it is determined whether the force of the hand is weaker than a predetermined reference value (force threshold). This reference value is pre-stored in the memory of the control device 50. If the force of the hand is weaker than the reference value, the process proceeds to step S103, where it is determined whether the speed of the hand is slower than the reference value (speed threshold). If the speed of the hand is slower than the reference value, the process proceeds to step S104, where it is determined whether the position of the hand is within a reference range (permissible motion range). If the position of the hand is within the reference range, the motion control process is terminated. In the following description, each reference value and reference range is also referred to as a "determination reference."

[0039] On the other hand, if any of the three requirements shown in steps S102 to S104 is not met, the process for emergency stop and for abnormality notification is executed in step S105, and then this operation monitoring process is terminated. In the process for emergency stop, the power supply to the motors 35 and 45 is forcibly cut off to stop the robot 20 (hereinafter, also referred to as emergency stop). In the process for abnormality notification, a warning lamp provided on the robot 20 is turned on, and information that an abnormality has occurred is transmitted to the management system of the factory 10. Thus, in this embodiment, the force, speed, and position of the hand of the robot 20 are operation monitoring parameters for monitoring the operation of the robot 20.

[0040] The parameters for monitoring the operation are not limited to the force, speed, and position of the hand of the robot 20. Instead of or in addition to these, parameters indicating the force (rotational torque), speed (rotational speed), and position of each joint (axis) can also be used as parameters for monitoring the operation.

[0041] In this embodiment, the judgment criteria of the operation monitoring parameters also function as targets for suppressing (limiting) the movement of the robot arm 41 (specifically, the hand). For example, when a user directly touches the robot arm 41 or the like to teach the robot 20 a movement, the robot arm 41 may be pushed and pulled by the force of the force, resulting in a movement that exceeds the judgment criteria. Even in such a case, the movement of the robot arm 41 is corrected so as to fall within a range that does not exceed the judgment criteria, thereby suppressing frequent emergency stops caused by the judgment criteria being exceeded during work.

[0042] Here, when the robot 20 is engaged in various tasks, it is assumed that the safety functions will become uniform, making it difficult to improve both safety and work efficiency. In this embodiment, taking such circumstances into consideration, the safety functions of the robot 20, specifically, the judgment criteria for each operation monitoring parameter, are made switchable in multiple stages. Hereinafter, a configuration related to switching of the safety functions will be described with reference to FIG. 8.

[0043] Three control devices are provided as control devices capable of switching the safety functions of the safety-related part X: (1) a teaching pendant 60, (2) a drive control part 51 (more specifically, a pack script), and (3) an external general-purpose input / output (hereinafter, referred to as IO). All of these three control devices correspond to the non-safety-related part Y.

[0044] An application for switching safety functions is installed on the teaching pendant 60, and when a user performs an operation to switch the judgment criteria of the operation monitoring parameters, a command (request command) instructing the switching and diagnostic information (CRC) for diagnosing whether the command has been normally transmitted or received are transmitted to a safety FPGA (Field Programmable Gate Array) of the safety-related unit X. The safety FPGA switches the judgment criteria of the operation monitoring parameters based on this command. For example, when a user performs the above-mentioned teaching, the judgment criteria of the operation monitoring parameters can be switched according to the user's operation to suitably prevent the safety functions from interfering with the teaching work. Note that the specific configuration of the logic unit X2 of the safety-related unit X is not limited to the safety FPGA, and it may be a microcomputer or a CPU.

[0045] In addition, sensors and the control center of the factory 10 are connected to the IO in a communicable manner, and switching of safety functions is permitted from external devices other than the teaching pendant.

[0046] Moreover, the robot control system CS shown in this embodiment is configured to be able to actively switch safety functions based on the judgment of the control device 50. Specifically, the judgment criteria for the operation monitoring parameters are switched depending on the work scene of the robot 20. Below, a task monitoring process executed as part of the regular process by the drive control unit 51 to realize such switching will be described.

[0047] In the operation program of the robot 20, the movement of the robot 20 in a work scene is defined by a combination of multiple tasks. In the task monitoring process shown in FIG. 9, first, in step S201, it is determined whether or not all tasks related to the work currently being performed have been completed.

[0048] If it is not the time when all tasks have been completed, a negative determination is made in step S201, and the task monitoring process ends. If it is the time when all tasks have been completed, a positive determination is made in step S201, and the process proceeds to step S202. The above operation program referenced by the drive control unit 51 includes information for identifying the next work scene when the last task is completed, and in step S202, the next work scene is identified based on this information.

[0049] In the next step S203, an instruction to switch the safety function to the safety FPGA of the safety-related unit X is determined according to the work scene identified in step S202. Specifically, a request command requesting switching of the safety function and a CRC, which is diagnostic information for diagnosing whether the transmission and reception of the request command have been performed normally, are set. The safety functions in this embodiment are defined for each work scene (scenes SN1 to SN9) of the robot 20. In other words, the request command set in step S203 can be said to request the safety-related unit X to switch the work scene. In view of these circumstances, the request command instructing switching of the safety function can also be said to be a "scene change command."

[0050] Here, the request command and CRC will be further explained with reference to Fig. 10. The request command is composed of information for identifying the control device that is the sender, a command ID including information indicating that the current request is to switch a safety function, and data (scene number) indicating the criteria to be referred to in subsequent judgments.

[0051] If the sender of the request command for switching the safety function is the teaching pendant 60, the command ID will be "11". If the sender is the drive control unit 51 (more specifically, the pack script), the command ID will be "12". If the sender is the IO, the command ID will be "13".

[0052] Furthermore, when a request command for switching the safety function is set, the data is one of the nine numbers from "1" to "9." For example, if the next work scene is scene SN3 (picking), the data is "3," if the next work scene is scene SN4 (transport), the data is "4," and if the next work scene is scene SN5 (palletizing), the data is "5."

[0053] The CRC is a checksum of the command ID and the data number. For example, if the drive control unit 51 is the sender and the next work scene is the transportation of scene SN4, the CRC will be "12" + "4" = "16".

[0054] After the request command and CRC are set in step S203, the scene change sequence is started in step S204, and the task monitoring process ends (see FIG. 9). After this, the task monitoring process is avoided until the scene change sequence ends.

[0055] Next, a scene change sequence executed by the non-safety-related part Y and the safety-related part X (specifically, the safety FPGA) will be described with reference to FIG.

[0056] In the scene change sequence, first, the non-safety-related part Y instructs the safety-related part X to switch the safety function of the safety-related part X, specifically, to switch the judgment criteria for the operation monitoring parameters. Specifically, it sends a request command and CRC to the safety-related part X (see ts1).

[0057] Based on the instruction received from the non-safety-related part Y, the safety-related part X diagnoses whether or not there is any abnormality such as damage in the current request command and CRC. Specifically, it judges whether or not the sum of the command ID number and the data number of the request command matches the CRC (see ts2). If they match, it assumes that the current instruction was sent and received normally, and then diagnoses whether or not the request command itself is normal. Specifically, it refers to the command ID to identify that the current instruction is to switch a safety function, and judges whether or not the data is within the range corresponding to the current command ID (see ts3). As described above, if the command ID is "11" to "13", the data will be any of "1" to "9". If the current data is any of "1" to "9", it judges that the request command is normal.

[0058] If ts2 or ts3 is diagnosed as abnormal, a notification is sent to the control center of the factory 10 or the like that a communication error or other abnormality has occurred, and this scene change sequence is terminated.

[0059] If the current request command is diagnosed as normal, the command is accepted and the safety function, i.e., the judgment criteria for the operation monitoring parameters, are switched in response to an instruction from the non-safety-related unit Y (see ts4). Specifically, the safety-related unit X (more specifically, the memory of the control device 50) stores the correspondence between the data numbers and each operation monitoring parameter. The operation monitoring parameters are switched based on the specified data number and the correspondence stored in the memory.

[0060] 12, when the next work scene is "picking" with data "3", the criterion for the force motion monitoring parameter is 70 N, the criterion for the speed motion monitoring parameter is 125 mm / s, and the criterion for the position motion monitoring parameter is the upper area of ​​the AGV 31 + the outer area of ​​the AGV 31 taking into account the workpiece picking operation (the outer area in a plan view of the robot 20). In this case, the robot 20 is brought to an emergency stop when any of the following conditions is met: the force of the hand exceeds 70 N, the speed of the hand exceeds 125 mm / s, or the position of the hand is outside the upper area of ​​the AGV 31 + the extended area for picking.

[0061] If the next work scene is "transport" with data "4", the criterion for the force motion monitoring parameter is 140 N, the criterion for the speed motion monitoring parameter is 250 mm / s, and the criterion for the position motion monitoring parameter is the upper region of the AGV 31. In this case, the robot 20 will be brought to an emergency stop when any of the following conditions occurs: the force of the hand exceeds 140 N, the speed of the hand exceeds 250 mm / s, or the position of the hand goes outside the upper region of the AGV 31 (when the robot arm 41 protrudes from the AGV 31 in a plan view).

[0062] If the next work scene is "palletizing" with data "5", the judgment criteria for the force motion monitoring parameters = upper capacity limit (maximum strength) + αN, the judgment criteria for the speed motion monitoring parameters = upper capacity limit (maximum speed) + βmm / s, and the judgment criteria for the position motion monitoring parameters = upper capacity limit (maximum range of motion) + γ. In this case, since all of the judgment criteria exceed the upper capacity limit, an emergency stop is essentially avoided.

[0063] Returning to the explanation of Fig. 11, after the switching of the safety function (criteria for the operation monitoring parameters) is completed, the fact that the instruction has been accepted is reported to the non-safety-related part Y. Specifically, an acknowledge signal is sent to the non-safety-related part Y (see ts5). When an acknowledge signal arrives from the safety-related part X, the non-safety-related part Y requests information for identifying the settings of the safety function after switching from the safety-related part X, that is, information for identifying the criteria for the operation monitoring parameters currently set as the reference target (see ts6). A CRC may also be added to this request.

[0064] In response to a confirmation request from a non-safety-related part Y, the safety-related part X sends to the non-safety-related part Y a request command (more specifically, a command simulating a request command) and a CRC, which is diagnostic information for diagnosing whether the transmission and reception of the request command was performed normally (see ts7). The request command from the safety-related part X, like the above request command from the non-safety-related part Y, is composed of information for identifying that the sender is the safety-related part X, a command ID including information indicating that the current request is a switching of a safety function, and data (scene number) indicating a judgment criterion to be referred to in subsequent judgments. The CRC is the sum of the command ID number and data number of the command to be responded to this time. For example, if the current setting corresponds to "palletizing" of scene SN5 in response to a request from the non-safety-related part Y, the command ID="19", data number="5", and CRC="24" are returned. Incidentally, it is sufficient for the CRC to be determined based on the command ID and data number, and the specific calculation method is arbitrary.

[0065] Note that the sum of the command ID and data of the request command sent from safety-related section X to non-safety-related section Y does not match the sum of the command ID and data of the request command sent from non-safety-related section Y to safety-related section X at the start of the current sequence. Similarly, the CRC accompanying the request command sent from safety-related section X to non-safety-related section Y does not match the CRC accompanying the request command sent from non-safety-related section Y to safety-related section X at the start of the current sequence.

[0066] Upon receiving the response from the safety-related part X, the non-safety-related part Y diagnoses whether the current response was sent and received normally based on the request command and CRC. Specifically, it determines whether the sum of the command ID number and the data number of the request command matches the CRC (see t8). If they match, it assumes that the current response was sent and received normally, and then it determines whether the safety function of the safety-related part X was switched normally in response to the request from the non-safety-related part Y (see t9). Specifically, the non-safety-related part Y stores the relationship between the command ID and data of the request command from the safety-related part X, and based on this relationship, it determines whether the command ID and data of the request command it sent to the safety-related part X match.

[0067] When it is confirmed that the response from safety-related part X matches its own instructions, the scene change sequence is completed.

[0068] According to the first embodiment described above in detail, the following excellent effects can be expected.

[0069] When switching the safety function (criterion), a switching instruction is given from the non-safety-related part Y to the safety-related part X. This instruction is composed of a request command and a CRC, and the safety-related part X diagnoses whether the instruction has been received normally based on the request command and the CRC, and diagnoses whether the instruction itself is normal. If the diagnosis shows no abnormality, the instruction from the non-safety-related part Y is accepted, and the safety-related part X switches the judgment criterion to be referred to in accordance with the instruction. In other words, even if the instruction is from the non-safety-related part Y, if it is determined that the instruction is not abnormal due to a transmission error or the like, the judgment criterion is switched. In this way, if safe switching from the non-safety-related part Y is realized, the operability of changing the safety function in the robot control system CS can be suitably improved.

[0070] Next, safety-related section X notifies non-safety-related section Y that it has received the instruction, and upon receiving the notification, non-safety-related section Y requests information from safety-related section X that can identify the judgment criterion currently being referenced (the judgment criterion after switching). In response to this, safety-related section X sends a group of information consisting of that information and a CRC to non-safety-related section Y. Non-safety-related section Y diagnoses based on the CRC whether the response from safety-related section X has been received normally, and whether the judgment criterion that has actually been set is the judgment criterion specified by the original instruction. In other words, non-safety-related section Y is able to confirm whether the switching of the safety function in safety-related section X has been performed normally by its own instruction.

[0071] According to the configuration shown in this embodiment, even when switching the safety function of the safety-related part X from the non-safety-related part Y, it is possible to suppress a decrease in reliability with respect to the change of the safety function, and it is possible to avoid stricter restrictions on the change as compared with the case where the input for changing the safety function is an input from the input part X1 (so-called safety input). This makes it possible to suitably improve the operability of changing the safety function.

[0072] Incidentally, when the robot 1 is engaged in various tasks, being able to change (operate) the safety function according to the task is advantageous in improving the robot's work efficiency while taking safety into consideration. Making it possible to switch the safety function from non-safety-related part Y encourages the application of robots to multiple types of tasks, which is also desirable in promoting factory automation.

[0073] As shown in this embodiment, if the configuration is such that the safety-related part X diagnoses whether the command from the non-safety-related part Y itself is normal by comparing the type of command pre-stored in the safety-related part X with the current command, when the command is damaged due to a stuck bit, a communication error, or the like, it is possible to preferably prevent the safety function from being switched based on the damaged command.

[0074] When switching between multiple types of judgment criteria (force criteria, speed criteria), instead of specifying each judgment criterion individually, a combination of those criteria (scene number) that has been defined in advance can be specified to prevent instructions from the non-safety-related part Y to the safety-related part X from becoming complicated. This is a preferable configuration for increasing the number of tasks that the robot can perform while taking into consideration safety functions.

[0075] It is preferable for one robot to take on multiple different tasks in order to promote the automation of manufacturing and the like. However, if the safety functions of the robot are made uniform regardless of the work scene, it becomes difficult to improve both safety and work efficiency. In this respect, in the configuration shown in this embodiment, the work scene is identified and the monitoring judgment criteria are changed for each work scene. This contributes to improving the safety of the robot and improving work efficiency.

[0076] Here, in order to improve the safety of the robot, it is also possible to configure the safety functions to be changed sequentially every time the operating state (position, orientation, speed, etc.) of the robot changes. However, such a configuration increases the control load in the robot control system, affecting the original function of the robot control system (driving control of the robot). In this regard, considering that the movement of the robot changes for each task, there is a clear technical significance in that the configuration shown in this embodiment in which the judgment criteria are switched for each task scene can improve safety while minimizing the impact on the original function of the robot control system.

[0077] If the work scene can be identified based on the scene-related information included in the operation program, the robot control system can quickly select the judgment criteria for each work scene by itself. This can reduce the long waiting time required for switching safety functions and contribute to improving work efficiency.

[0078] Furthermore, making the judgment criteria switchable is preferable in terms of improving the workability of the robot while taking into consideration the safety of the robot. However, when such a switching function is provided, the following new concerns arise. That is, if the judgment criteria are suddenly switched during the first task due to an accidental reason, an event may occur in which a movement that is not problematic in the first task is caught by monitoring. This unnecessarily increases the chances of emergency stops of the robot, which reduces the work efficiency. Therefore, as shown in this embodiment, a practically preferable configuration can be realized by preventing the switching of the judgment criteria according to the work scene until the first task being performed is completed, thereby suppressing the occurrence of the above-mentioned event.

[0079] In addition, by making it possible to switch the criteria for the motion monitoring parameters indicating the hand position as well as the criteria for the motion monitoring parameters indicating the force and speed, it is possible to prevent the monitoring of the robot's force and speed from becoming excessively strict, which is preferable in terms of improving the work efficiency of the robot.

[0080] <Second embodiment> The robot control system CS shown in the first embodiment realizes improvements in the work efficiency and safety of the robot 20 by changing the safety functions according to the work scene. One of the features of this embodiment is that a smooth transition of the work scene is implemented when changing the safety functions. Hereinafter, the phenomenon of interest will be described with reference to FIG. 13.

[0081] Changes in the judgment criteria (reference value) when a work scene is switched can be broadly classified into the following two patterns. That is, a pattern in which the reference value is raised by switching the work scene as shown in Fig. 13(a), and a pattern in which the reference value is lowered by switching the work scene as shown in Fig. 13(b). In the following explanation, the force of the hand of the robot 20 is exemplified, but a similar phenomenon also occurs with the speed of the hand.

[0082] In the example shown in FIG. 13(a), the force (detection value) of the hand of the robot 20 in the work scene before switching is changed to be lower than the reference value. At the timing t0 when the work scene is switched, the reference value is raised, and the difference between the detection value and the reference value is large. In other words, even if the reference value is raised in accordance with the switching of the work scene, the detection value remains below the reference value. Although the above-mentioned output restrictions and the like are relaxed by the switching of the work scene, and the force and speed of the hand of the robot 20 can increase, the detection value does not jump up instantly due to the work schedule, the delay of the motor movement, and the like. For this reason, immediately after the switching of the work scene, specifically, at the timing t1 which is the first monitoring period (sampling period) after the switching of the work scene, the detection value remains below the newly set reference value. In other words, an event does not occur in which the detection value exceeds the reference value at the switching of the work scene and the robot 20 is stopped in an emergency.

[0083] In contrast, in the example shown in FIG. 13(b), the force (detection value) of the hand of the robot 20 in the work scene before switching is changed to be lower than the reference value. In this respect, it is similar to the example shown in FIG. 13(a). However, in FIG. 13(a), the reference value is raised (the judgment criterion is loose) at the timing t0 when the work scene is switched, whereas in FIG. 13(b), the reference value is lowered (the judgment criterion is strict) at the timing t0 when the work scene is switched. As in the pattern L in FIG. 13(b), when the detection value changes to be lower than both the pre-switching and post-switching reference values ​​in the period until the timing t0, the detection value does not exceed the post-switching reference value at the timing t0 or the immediately following timing t1. On the other hand, as in the pattern H in FIG. 13(b), when the detection value changes between the pre-switching reference value and the post-switching reference value in the period until the timing t0, the detection value exceeds the post-switching reference value at the timing t0 or the immediately following timing t1. Even if the output restrictions and the like become stricter as the work scene is switched thereafter, the detected value does not necessarily immediately fall below the post-switching reference value. If such an event occurs and the robot 20 is brought to an emergency stop, that is, an emergency stop at a timing that would not normally be necessary, this can be an obstacle to improving the reliability of the robot 20 and the work efficiency (production efficiency) of the robot 20.

[0084] In this embodiment, the configuration for switching work scenes is devised in consideration of such circumstances. The devise, specifically, the scene switching monitoring process executed by the monitoring control unit 52 as part of the operation monitoring process (periodic process), will be described below with reference to the flowchart in Fig. 14. Note that, for the sake of convenience, Fig. 14 shows the time scale of the portion immediately after switching of the work scene and the time scale of the portion where the detection value normally exceeds the reference value as being enlarged compared to the time scale of the other portions.

[0085] In the scene switching monitoring process, first, in step S301, it is determined whether or not a special monitoring flag is set in a flag storage area of ​​memory. If the special monitoring flag is not set, a negative determination is made in step S301 and the process proceeds to step S302. In step S302, it is determined whether a work scene has been switched. Specifically, it is determined whether an instruction to switch safety functions has been received from non-safety-related unit Y. If a work scene has not been switched, the monitoring process ends as is. If a work scene has been switched, the process proceeds to step S303. In step S303, the determination criterion is switched. Specifically, the reference value referenced in the operation determination is switched to a reference value corresponding to the new work scene. In the following step S304, a special monitoring flag is set in the flag storage area of ​​memory and the monitoring process ends.

[0086] For convenience, the work scene before switching will be referred to as "work scene A", the reference value corresponding to work scene A will be referred to as "reference value FA", the work scene after switching will be referred to as "work scene B", and the reference value corresponding to work scene B will be referred to as "reference value FB".

[0087] Returning to the explanation of step S301, if the special monitoring flag is set, it is determined in step S305 whether it is time to check the movement of the robot 20 (hands) for the first time after the work scene is switched from work scene A to work scene B. Specifically, the memory is provided with a counter for tracking the number of times this monitoring process is executed after switching the work scene. The value n of this counter changes from "0" to "1" when the special monitoring flag is set, and thereafter is incremented by 1 each time this monitoring process is executed, and is cleared to 0 when the special monitoring flag is cleared. In step S305, it is determined whether it is time for the first check by referring to the value n of this counter.

[0088] If a positive determination is made in step S305, the process proceeds to step S306. In step S306, it is determined whether the current detection value Ft1 is below the post-switching reference value FB. If the detection value Ft1 is below the reference value FB, the special monitoring flag is cleared in step S307, and the monitoring process ends. If the detection value Ft1 has reached the reference value FB, a negative determination is made in step S306, and the process proceeds to step S308, where an interrupt for the force and speed reduction control is started.

[0089] In the process of step S308, the drive control of the drive motor 45 is intervened to suppress the movement of the hand of the robot 20. Specifically, the power supplied to the drive motor 45 is limited to a certain degree. This reduction control interruption continues until the monitoring cycle is repeated until it reaches the upper limit number of times, n times (until a predetermined period has elapsed). The degree of limitation and the upper limit number of times may be calculated based on the reference values ​​FA and FB when the process of step S308 is executed, or may be read out from those registered in advance in a program bank or the like. Incidentally, this reduction control interruption does not stop the robot 20.

[0090] The detection value is forcibly reduced by starting the reduction control interrupt in step S308. In the following step S309, a reduction control target value Tn (intermediate target value Tn or target value Tn) of the detection value Ftn in each monitoring cycle after the reduction control interrupt is started is set. Specifically, the reduction rate by the reduction control in step S308 is specified to be constant, and the reduction control target value Tn is set based on the reduction rate and the detection value Ft1.

[0091] Returning to the explanation of step S305, if it is determined that the timing is not the first check, that is, if it is determined that the timing is the second or later check, the process proceeds to step S310. In step S310, it is determined whether the current detection value Ftn is below the current reduction control target value Tn set in step S310. If the current detection value Ftn is not below the current reduction control target value Tn, an unexpected movement (abnormality) may have occurred in the robot 20, so in step S311, processes for emergency stop and abnormality notification are executed, and then the monitoring process is terminated. In the emergency stop process, the power supply to the motors 35 and 45 is forcibly cut off to bring the robot 20 to an emergency stop. Then, in the abnormality notification process, a warning lamp provided on the robot 20 is turned on, and information indicating that an abnormality has occurred is transmitted to the management system of the factory 10.

[0092] Returning to the explanation of step S310, if the current detection value Ftn is below the current reduction control target value Tn, an affirmative determination is made in step S310 and the process proceeds to step S312. In step S312, it is determined whether the current detection value Ftn is below the reference value FB, which is the reference value after switching. If a negative determination is made in step S312, the process proceeds to step S313 and it is determined whether the number of times this monitoring process has been executed in this monitoring period, i.e., after switching of the work stage, has reached the upper limit number set in step S309. If it is determined that the upper limit number has been reached, the process proceeds to step S311. Normally, a reduction control interrupt is performed so that the detection value falls below the reference value before the upper limit number is reached, but if the detection value has not yet been reduced to fall below the reference value even when the upper limit number is reached, it is assumed that an unexpected movement (abnormality) may have occurred in the movement of the robot 20. Therefore, in step S311, an emergency stop of the robot 20 and an abnormality notification are performed, and then the monitoring process is terminated. If it is determined in step S313 that the upper limit number has not been reached, the counter value n is incremented by "1" in step S314, and this monitoring process is terminated.

[0093] Returning to the explanation of step S312, if the determination in step S312 is affirmative, i.e., if the detection value Ftn is below the post-switching reference value FB, the process proceeds to step S315. In step S315, the interruption of the reduction control is ended. This ends the forced reduction of the detection value. Thereafter, in step S316, the special monitoring flag is cleared, and the monitoring process is ended.

[0094] Here, a supplementary explanation will be given of the change in the detection value accompanying the switching of the work scene from work scene A to work scene B with reference to the timing chart of FIG.

[0095] At time t0 when work scene A switches to work scene B, the detection value (detection value Ft0) is between reference value FA and reference value FB. At time t1 immediately after the work scene switches, that is, at time t1 of the next cycle following time t0, the detection value Ft1 remains above reference value FB. Normally, an emergency stop and abnormality notification would be performed at this point, but the emergency stop and abnormality notification based on this detection value are avoided. Then, at time t1, a reduction control interrupt is initiated to forcibly reduce the detection value.

[0096] In each of the subsequent cycles (timings t2 to t4), the detection values ​​Ft2 to Ft4 are below the reduction control target values ​​T2 to T4, respectively, and the detection values ​​are reduced as planned. Then, at timing t5, the detection values ​​fall below the reference value FB as planned before the cycle reaches the upper limit number of times. This ends the reduction control interrupt. If the detection values ​​were not reduced as planned in the timings t2 to t5, an emergency stop and an abnormality alert would be executed at that point.

[0097] After the interruption of the reduction control ends at t5, the actual detection value also basically remains below the reference value FB. Then, as shown at t6 to t7, when the detection value changes to reach the reference value FB, an emergency stop and an abnormality notification are executed.

[0098] According to the configuration described above in detail, even when the safety function is changed in accordance with a change in the work scene, the chances of the robot 20 being stopped in an emergency (mis-stop) due to the change can be reduced. In this way, suppressing the mis-stop of the robot 20 is preferable in terms of improving the production efficiency by the robot 20.

[0099] The configuration shown in this embodiment can also be applied to a configuration in which the distance to a person is detected using a laser scanner 37 or the like, and the work scene of the robot 20 (for example, a human collaboration scene) is switched depending on the detection result of the distance to the person. Specifically, further safety enhancement can be expected by configuring the reference value (close distance reference value) when the distance between the robot 20 and a person is relatively close to the person to be lower than the reference value (long distance reference value) when the distance is relatively far. However, since the distance to a person may change suddenly, the above-mentioned erroneous stop may occur more frequently when the reference value changes from high to low, which may have a significant impact on productivity, etc. In this regard, if the configuration shown in this embodiment is applied, erroneous stop of the robot 20 can be suppressed even when the work scene is suddenly switched from a long distance work scene to a short distance work scene.

[0100] <Third embodiment> In the second embodiment, the interruption of the reduction control is started when the work scene is switched. In this embodiment, the configuration related to the interruption of the reduction control is different from that of the second embodiment. Hereinafter, the scene switching monitoring process in this embodiment will be described with reference to the flowchart in FIG. 16, focusing on the differences from the second embodiment.

[0101] In the scene change monitoring process in this embodiment, first, in step S401, it is determined whether or not a switching preparation flag is set in memory. If the switching preparation flag is not set, the process proceeds to step S402. If a work scene change has occurred in step S402, the determination criteria are switched in step S403, specifically, the reference value FA is changed to the reference value FB, and then the monitoring process is terminated.

[0102] If no change in the work scene has occurred, proceed to step S404. In step S404, the progress of the current work is grasped. In the following step S405, it is determined whether the current detection value Fx is below the reference value (reference value FB) of the next scheduled work scene (work scene B). If the detection value Fx is below the reference value FB, the monitoring process is terminated. If the detection value Fx has reached the reference value FB, proceed to step S406.

[0103] In step S406, it is determined whether it is time to start interrupting the force and speed reduction control based on the difference between the current detection value Fx and the reference value FB and the remaining time (e.g., estimated time) until the next scheduled work scene. In other words, it is determined whether it is the appropriate timing to reduce the detection value to be lower than the reference value FB within the remaining time. If a negative determination is made in step S406, and there is still time remaining in consideration of the current detection value, etc., the monitoring process is terminated as is. If it is determined in step S406 that it is the appropriate timing, an interruption of the reduction control is started in step S408. In this interruption of the reduction control, the drive control of the drive motor 45 is intervened to suppress the movement of the hand of the robot 20. Specifically, the power supplied to the drive motor 45 is limited to a certain degree.

[0104] In this embodiment, the appropriate timing is set to be "variable", but it may be set to be "fixed". In other words, when the remaining time reaches a predetermined time, the reduction control interrupt may be started on the condition that the detected value at that time exceeds the reference value FB.

[0105] Thereafter, in step S406, a switching preparation flag is set in the flag storage area of ​​the memory, and this monitoring process ends.

[0106] Returning to the explanation of step S401, if it is determined that the switching preparation flag is set in the flag storage area of ​​the memory, the process proceeds to step S409. In step S409, it is determined whether a switching of the work scene has occurred. If a switching of the work scene has occurred, the determination criterion is switched in step S410, specifically, the reference value FA is changed to the reference value FB. Thereafter, in step S411, it is determined whether the current detection value Ft0 is below the reference value FB. As described above, in this embodiment, a switching of the work scene is detected in advance, and a reduction control interrupt is executed with the aim of the switching. As a result, at the timing when the switching of the work scene is executed, the detection value Ft0 is basically below the reference value FB.

[0107] If an affirmative determination is made in step S411, the interruption of the reduction control is ended in step S412, the switching preparation flag is cleared in step S413, and this monitoring process is ended.

[0108] If a negative determination is made in step S411, then in step S414, the processes for emergency stop and abnormality notification are executed, and then this monitoring process is terminated.

[0109] Here, with reference to the timing chart of FIG. 17, a supplementary explanation will be given of the change in the detection value when the work scene is switched from work scene A to work scene B.

[0110] At a timing tx prior to the timing t0 when work scene A switches to work scene B, the detection value (detection value Fx) is located between the reference value FA corresponding to the current work scene A and the reference value FB corresponding to the next work scene B. At the timing tx, the next work scene B and the remaining time until said next work scene B are specified in advance, and based on the current detection value, the reference value FB corresponding to the next work scene B, and the remaining time until the timing t0, it is determined that it is an appropriate timing to start an interruption of the reduction control, and the interruption of the reduction control is started.

[0111] At time t0 when work scene A switches to work scene B, the reference value switches from reference value FA to reference value FB, and it is determined whether the current detection value is below reference value FB. If the detection value is reduced as planned by the interruption of the reduction control, the detection value will fall below reference value FB at time t0, and emergency stop of the robot 20 will not be executed. On the other hand, if the detection value is not reduced as expected for some reason and reaches reference value FB at time t0, an emergency stop of the robot 20 will be executed.

[0112] As described above in detail, by providing a reduced control period (buffer area) before the work scene is switched, even if the safety function is changed in accordance with the switching of the work scene, the chances of the robot 20 being stopped in an emergency (erroneous stop) due to the change can be reduced. Suppressing erroneous stops of the robot 20 in this way is preferable in terms of improving the production efficiency of the robot 20.

[0113] <Fourth embodiment> The robot 20 shown in this embodiment is configured to estimate the distance to a person using a laser scanner 37, and switch the work scene of the robot 20 (for example, palletizing in scene SN5 where collaboration with a person is not assumed) between a work scene where a person is not assumed (hereinafter referred to as work scene 1) and a work scene where a person is assumed (hereinafter referred to as work scene 2) depending on the result of detecting the distance from the person, and the safety function (criterion) is changed when switching, which is different from the first embodiment. Considering that the criterion (criterion F1) in work scene 1 is lower than the criterion (criterion F2) in work scene 2, it can be said that work scene 2 is a scene where greater consideration is given to safety than work scene 1.

[0114] As shown in FIG. 18, the detection area (monitoring area) by the laser scanner 37 includes a peripheral area CE1 in the immediate vicinity of the robot 20, a non-detection area CE3 outside the monitoring by the laser scanner 37, and a buffer area CE2 set between the peripheral area CE1. When the robot 20 is working in the accumulation area E3, the work scene is the work scene 1 in which no human presence is assumed, and when a human approaching the robot 20 enters the peripheral area CE1 (when a human is detected in the peripheral area CE1), the work scene 1 is switched to the work scene 2. In this embodiment, when such an unexpected switching occurs, the technical idea shown in the third embodiment is applied, and advance preparation for switching the work scene is performed, thereby improving safety and production efficiency (work efficiency). Hereinafter, a configuration related to the advance preparation, specifically, a special switching time monitoring process executed as part of the operation monitoring process in the monitoring control unit 52 will be described with reference to the flowchart in FIG. 19.

[0115] In the special switching monitoring process, first, in step S501, it is determined whether or not a switching preparation flag is set in the memory. If the switching preparation flag is not set, the process proceeds to step S502. In step S502, it is determined whether or not an object (person) is detected in the buffer area CE2 based on information from the laser scanner 37. If a negative determination is made in step S502, the monitoring process is terminated. If a positive determination is made in step S502, the process proceeds to step S503, where the determination criterion (reference value) for the next work scene is confirmed in advance. Specifically, if a person enters the buffer area CE2, there is a possibility that the person will enter the surrounding area CE1, and if an intrusion into the surrounding area CE1 is confirmed, the work scene is switched from the above work scene 1 to work scene 2. Therefore, in step S503, the reference value F2 in the case of work scene 2 is confirmed in advance.

[0116] In the next step S504, it is determined whether the current detection value Fx is below the reference value F2 of the work scene 2 that is expected to be switched to next. If the detection value Fx is below the reference value F2, the monitoring process ends. If the detection value Fx has reached the reference value F2, the process proceeds to step S505.

[0117] In step S505, a force and speed reduction control interrupt is started. In this reduction control interrupt, the drive control of the drive motor 45 is intervened to suppress the movement of the hand of the robot 20. Specifically, the power supplied to the drive motor 45 is restricted to a certain degree. After that, in step S506, a switching preparation flag is set in a flag storage area of ​​the memory, and this monitoring process is terminated.

[0118] Returning to the explanation of step S501, if it is determined that the switching preparation flag is set in the flag storage area of ​​the memory, the process proceeds to step S507. In step S507, it is determined whether or not an object (person) has been detected in the buffer area CE2. If a negative determination is made in step S507, that is, if an object (person) is no longer detected in the buffer area CE2, the process proceeds to step S508, where the interruption of the reduction control is terminated. Thereafter, in step S509, the switching preparation flag is cleared, and this monitoring process is terminated.

[0119] On the other hand, if a positive determination is made in step S507, the process proceeds to step S510. Note that, even if an object (person) is detected in the surrounding area CE1, a positive determination is made in step S507, and the process proceeds to step S510.

[0120] In step S510, it is determined whether a switch from work scene 1 to work scene 2 has occurred. Specifically, it is determined whether an object (person) has been detected in the surrounding area CE1. If a switch to work scene 2 has occurred, in step S511 the determination criterion is switched, specifically, from reference value F1 to reference value F2. Thereafter, in step S512, it is determined whether the current detection value Ft0 is below reference value F2. As described above, in this embodiment, a switch of work scenes is predicted in advance, and a reduction control interrupt is executed with the aim of the switch. As a result, at the timing when the switch of work scenes is executed, the detection value Ft0 will basically be below reference value F2.

[0121] If an affirmative determination is made in step S512, the interruption of the reduction control is ended in step S508, the switching preparation flag is cleared in step S509, and this monitoring process is ended.

[0122] If a negative determination is made in step S512, then in step S513, the processes for emergency stop and abnormality notification are executed, and then this monitoring process is terminated.

[0123] As described above in detail, by providing a reduced control period before switching from work scene 1 to work scene 2, even if a safety function is changed in conjunction with switching of the work scene, the chances of emergency stopping (false stop) of the robot 20 due to the change can be reduced. Suppressing false stops of the robot 20 in this way is preferable in terms of improving production efficiency by the robot 20, etc.

[0124] In this embodiment, the case where the function related to switching between work scene 1 and work scene 2 is applied to the non-collaboration scene SN5 is illustrated, but the present invention is not limited to this. It is also possible to apply the function related to switching between work scene 1 and work scene 2 to other collaborative work scenes.

[0125] <Other embodiments> The present invention is not limited to the contents of the above-mentioned embodiments, and may be implemented, for example, as follows. Each of the following configurations may be applied individually to each of the above-mentioned embodiments, or may be applied in combination with some or all of the following configurations to each of the above-mentioned embodiments. It is also possible to arbitrarily combine all or some of the various configurations shown in each of the above-mentioned embodiments. In this case, it is preferable that the technical significance (effects exerted) of each of the configurations to be combined is guaranteed. Each of the following configurations may be applied individually to a new configuration consisting of a combination of the embodiments, or may be applied in combination with some or all of the following configurations.

[0126] In each of the above embodiments, the work scene (scenes SN1 to SN9) of the robot 20 is identified, and the judgment criteria for the operation monitoring parameters (force, speed, position) are switched according to the identified work scene, but this may be modified as follows. That is, in a configuration in which the type of work of the robot 20 differs for each area through which the robot 20 moves, it is also possible to identify the area in which the robot 20 is located, and switch the judgment criteria for the operation monitoring parameters according to the identified area. Also, in a case in which multiple tasks are performed in each area through which the robot 20 moves, or in a case in which the same task is performed in multiple areas, it is also possible to identify both the work scene of the robot 20 and the area in which the robot 20 is located, and switch the judgment criteria for the operation monitoring parameters according to them.

[0127] In a configuration in which the robot 20 executes a plurality of tasks (task routines) according to a predetermined time schedule, the progress of the task routine may be managed based on the time elapsed since the start of the routine or the current time, and the judgment criteria for the operation monitoring parameters may be switched based on the time or the current time. Also, in consideration of cases in which delays occur in the schedule, the judgment criteria for the operation monitoring parameters may be switched based on the time or the time and information indicating the delay time.

[0128] Furthermore, in addition to the configuration in which the judgment criteria are switched according to the work scene of the robot 20 as shown in each of the above embodiments, it is also possible to configure the judgment criteria to be switched according to the elapsed time or the current time. For example, in the factory 10, break times (lunch break, etc.) are often provided periodically, and it is assumed that there is a high possibility that the number of people in the passage E4, etc. increases during this time period. Taking such circumstances into consideration, it is preferable to configure the judgment criteria to be switched so that the judgment criteria when the robot 20 passes through the passage E4 during the break time are stricter than the judgment criteria when the robot 20 passes through the passage E4 outside the break time.

[0129] In each of the above embodiments, three motion monitoring parameters, force, speed, and position, are used in each work scene, but the type and number of motion monitoring parameters to be used as the judgment criteria may be changed depending on the work scene. For example, it is possible to use force and speed as motion monitoring parameters in a first scene, while using force, speed, and position as motion monitoring parameters in a second scene.

[0130] It is also possible to configure the work scenes shown in the above embodiments to be subdivided according to the type of operation of the robot 20, and to switch the judgment criteria for the operation monitoring parameters for each subdivided scene. For example, in the picking scene SN3, the scene of picking up the workpiece from the processing machine 14 and the scene of moving to the adjacent processing machine may be configured as separate scenes, and the judgment criteria may be switched. Furthermore, the judgment criteria may be switched between the first half of the workpiece picking scene (until the workpiece is grasped) and the second half (until the workpiece is moved to the container 18).

[0131] It is also possible to subdivide the work scene 1 into scenes in which the distance from people is expected to be relatively close and scenes in which the distance from people is expected to be relatively far, and to switch the judgment criteria for each of these subdivided scenes.

[0132] In each of the above embodiments, the judgment criteria for the motion monitoring parameters are switched when moving from the previous work scene to the next work scene. However, this is not intended to deny the possibility of changing this to a configuration in which the judgment criteria for the motion monitoring parameters are switched at the end of the previous work scene, or a configuration in which the motion monitoring parameters are switched at the beginning of the next work scene.

[0133] It is optional whether or not to allow the robot 20 to continue operating during the switching of the judgment criteria. When switching the judgment criteria of the operation monitoring parameters, the operation of the robot 20 may be temporarily stopped until the switching is completed. Also, it is possible to temporarily stop the robot 20 when the judgment criteria are switched to be stricter, while allowing the operation of the robot 20 to continue when the judgment criteria are switched to be looser.

[0134] In each of the above embodiments, a CRC is added as diagnostic information for diagnosing whether transmission and reception between the non-safety-related part Y and the safety-related part X is normal. The setting of this CRC is arbitrary, and does not necessarily have to be based on the command ID and data of the request command.

[0135] In the palletizing of scene SN5 shown in each embodiment above, values ​​that exceed the limits of the capabilities of the robot 20 with respect to the force, speed, and position, i.e. values ​​that cannot actually occur, are set as the judgment criteria for the operation monitoring parameters, but this may be changed and the operation monitoring may be skipped in the palletizing of scene SN5. In other words, the operation monitoring function of the robot 20 may be turned off in a specific work scene.

[0136] In each of the above embodiments, the judgment criteria for the motion monitoring parameters and the limitations of the force, speed, and position (movement area) are switched according to the work scene of the robot 20, but the present invention is not limited to this. It is sufficient to at least switch the judgment criteria for the motion monitoring parameters, and it is also possible to omit the switching of limitations.

[0137] In the above embodiments, the robot 20 is mobile, but the technical ideas shown in the above embodiments may be applied to a robot control system for a fixed robot. For example, in a configuration in which a fixed robot performs a plurality of different tasks depending on the type of workpiece supplied by a conveyor or the like, it is possible to determine the work scene and switch the judgment criteria for the operation monitoring parameters for each work scene. The work scenes may also be subdivided as described above, and the judgment criteria may be switched for each subdivided scene.

[0138] As shown in each of the above embodiments, making it possible to switch the judgment criteria for the operation monitoring parameters is preferable in terms of improving the workability of the robot 20 while taking into consideration the safety of the robot 20. However, when such a switching function is provided, the following new concerns arise. That is, if the judgment criteria suddenly switch during task 1 due to an accidental reason or the like, an event may occur in which a movement that would not be problematic otherwise is caught by the monitoring. This unnecessarily increases the chances of emergency stops of the robot 20, which reduces work efficiency. In view of these circumstances, there is technical significance in disabling (prohibiting) the switching of the judgment criteria until task 1 being performed is completed.

[0139] The items being transported are different in "Transport A" in scene SN4 and "Transport B" in scene SN8. Taking into account the difference in the conditions (e.g. weight) of the transported items, the safety functions (criteria for the operation monitoring parameters) in Transport A and the safety functions (criteria for the operation monitoring parameters) in Transport B may be set separately.

[0140] In each of the above embodiments, the request commands from each non-safety-related part Y (control device) are configured to share the same number (scene number = 1 to 9) that specifies the work scene, but this is not limited to this. A configuration in which the scene number is individual depending on which non-safety-related part Y the request command is from may also be used. For example, the scene numbers may be 1 to 9 for request commands when the control device is a teaching command, scene numbers may be 11 to 19 for request commands when the control device is a pack script, and scene numbers may be 21 to 29 for request commands when the control device is an IO.

[0141] In the safety-related unit X shown in each of the above embodiments, the judgment criteria of the operation monitoring parameters are stored in advance in association with the scene number, and each judgment criterion is specified from the scene number specified by the non-safety-related unit Y, but this is not limited to the above. The non-safety-related unit Y may be configured to send information indicating each judgment criterion individually to the safety-related unit X instead of the scene number of the work scene.

[0142] Incidentally, instead of the configuration in which the judgment criteria are stored in advance in the safety-related part X, a configuration in which a value indicating the judgment criteria is sent from the non-safety-related part Y to the safety-related part X may be adopted.

[0143] In the above embodiments, the robot 20 is applied to a processing line in the factory 10, but the application of the robot 20 is not limited to processing lines. The robot 20 can also be applied to an assembly line, an inspection line, or a packaging line. The movement range of the robot 20 is not limited to one line, and it can be configured to move across multiple lines, for example, to be engaged in individual tasks on each line.

[0144] <Inventions extracted from the above embodiments> The following describes the features of the inventions extracted from the above-mentioned embodiments, while indicating, as necessary, their effects, etc. In the following, for ease of understanding, the corresponding configurations in the above-mentioned embodiments are appropriately indicated in parentheses, but the present invention is not limited to the specific configurations indicated in parentheses.

[0145] <Feature A Group> Switching safety functions from non-safety related parts The following feature A group is related to the background technology of "Some robot control systems applied to robots such as industrial robots have safety-related parts that realize the safety functions of the robot and non-safety-related parts that perform drive control of the robot. As for the safety-related parts, for example, there have been proposals to forcibly stop the robot when it collides with an obstacle such as a person (see Patent Document 1), or to monitor the force (thrust) and speed of the robot while it is moving and forcibly stop the robot when it moves outside of safety standards." The feature A group is related to the background technology of "In recent years, with the advancement of robot technology, the types of work that robots (1) can perform are also on the rise. When robots (1) are to be performed in various tasks, it is important to be able to change (operate) the safety functions in order to take safety into consideration. This can be advantageous in improving the work efficiency of the robot while maintaining the safety of the robot. Here, in order to prevent the loss of the safety function due to a communication error or the like during the change, it is preferable that the input for changing the safety function is also an input from the safety-related input unit (so-called safety input). However, if the safety input is required, the constraints on the change will be stronger, which is expected to hinder improving the operability of changing the safety function. In contrast, if the requirement is simply avoided, although it is expected that the operability will be improved, the safety of the robot will decrease and there is a concern that trust in the safety function will be shaken. Thus, in order to improve the safety and work efficiency of the robot, there is still room for improvement in the configuration related to the change of the safety function. This was made in consideration of the background and issues, etc.

[0146] Feature A1. A robot control system (robot control system CS) provided with a safety-related part (safety-related part X) that realizes the safety function of the robot by generating a safety-related output signal according to the judgment result, the robot control system having a motion judgment part (logic part X2) that judges the motion of the robot based on a safety-related input signal (a signal from a rotary encoder 46, a torque sensor 47, etc.) including a parameter correlated with at least one of the force and speed of the robot (robot 20) during work and a judgment criterion (reference value or reference range) for the parameter that is stored in advance, and a non-safety-related part (non-safety-related part Y), a plurality of candidates for judgment criteria for the parameters to be referred to by the operation judgment unit included in the non-safety-related unit are provided, and the non-safety-related unit instructs the safety-related unit to switch the judgment criteria by sending to the safety-related unit an information group consisting of command information (a request command consisting of a command ID and data) indicating the judgment criteria to be referred to in the judgment by the operation judgment unit and first diagnosis information (CRC); when the safety-related part receives the instruction from the non-safety-related part, it diagnoses whether the instruction has been received normally based on the first diagnosis information, diagnoses whether the instruction itself is normal based on the command information, and when it has been diagnosed that the instruction has been received normally and that the instruction itself is normal, it accepts the instruction and switches a judgment criterion to be referred to in the judgment among the plurality of judgment criteria in accordance with the command information, and when it has received an instruction from the non-safety-related part, it notifies the non-safety-related part of that fact; when the safety-related part notifies the non-safety-related part that the instruction has been received, the non-safety-related part requests, from the safety-related part, identification information capable of identifying the judgment criterion set as a reference target by switching based on the instruction; the safety-related part responds to the request from the non-safety-related part by sending an information group consisting of the identification information and second diagnostic information (CRC) to the non-safety-related part; When the non-safety-related part receives the response from the safety-related part, the non-safety-related part diagnoses whether the response has arrived normally based on the second diagnostic information, and diagnoses whether the judgment criterion that is actually set is the judgment criterion specified by the instruction.

[0147] When switching the safety function (criterion), first, the non-safety-related part issues a switching instruction to the safety-related part. This instruction is composed of command information and first diagnostic information, and the safety-related part diagnoses whether the instruction has been received normally based on the first diagnostic information, and diagnoses whether the instruction itself is normal based on the command information. If the diagnosis shows no abnormality, the instruction from the non-safety-related part is accepted, and the safety-related part switches the judgment criterion to be referred to according to the instruction. In other words, even if the instruction is from a non-safety-related part, if it is determined that the instruction is not abnormal due to a transmission error or the like, the judgment criterion is switched. In this way, if safe switching from the non-safety-related part is realized, the operability related to the change of the safety function in the robot control system can be suitably improved. In other words, the safety function in the safety-related part is not changed unless the instruction from the non-safety-related part is normally received, thereby ensuring the reliability of safety control, while enabling the setting change by the operation from the non-safety-related part to realize an operation setting that takes user convenience into consideration, thereby improving the degree of freedom in setting the operation means.

[0148] Next, the safety-related part notifies the non-safety-related part that it has received the instruction, and upon receiving the notification, the non-safety-related part requests identification information that can identify the judgment criterion currently being referenced (the judgment criterion after switching) from the safety-related part. In response to this, the safety-related part sends an information group consisting of the identification information and the second diagnostic information to the non-safety-related part. The non-safety-related part diagnoses whether the response from the safety-related part has arrived normally based on the second diagnostic information, and diagnoses whether the judgment criterion that has actually been set is the judgment criterion specified by the original instruction. In other words, the non-safety-related part can confirm whether the switching of the safety function in the safety-related part has been performed normally by its own instruction.

[0149] According to the configuration shown in this feature, even when switching the safety function of the safety-related part from the non-safety-related part, it is possible to suppress a decrease in reliability with respect to the change of the safety function, and it is possible to avoid stricter restrictions on the change as compared with the case where the input for changing the safety function is an input from the safety-related input part (so-called safety input). This makes it possible to suitably improve the operability of changing the safety function.

[0150] Incidentally, for example, when the robot in 1 is engaged in various tasks, being able to change (operate) the safety functions according to the task is advantageous in improving the robot's work efficiency while taking safety into consideration. As shown in this feature, being able to switch safety functions from non-safety-related parts encourages the application of robots to multiple types of tasks, which is also desirable in promoting factory automation.

[0151] It should be noted that the "force and speed of the robot" in this characteristic includes not only the force and speed at the tool center point of the robot, but also the force (rotational torque) and speed (rotational speed) of each axis of the robot.

[0152] Feature A2. The command information is configured to be individual for each candidate of the judgment criterion; The safety-related unit is provided with a storage unit that stores a type of the command information, The robot control system according to feature A1, wherein the safety-related part, in the diagnosis of the safety-related part, checks whether the command information from the non-safety-related part is included in the types stored in the memory unit.

[0153] As shown by this feature, if the safety-related part is configured to diagnose whether the instruction (command information) itself from the non-safety-related part is normal by comparing the type of command information stored in advance with the current command information, then when the command information is damaged due to bit sticking, a communication error, or the like, it is possible to preferably prevent the safety function from being switched based on the damaged command information.

[0154] Feature A3. The non-safety-related parts are provided in plurality, the command information is composed of first information capable of identifying which of the non-safety-related parts the information is from, and second information specifying candidates for the judgment criterion to be referenced, The second information is configured to be individual for each of the first information, The storage unit stores a combination of the first information and the second information, The robot control system according to feature A2, wherein, in the diagnosis, the safety-related part checks whether a combination of the first information and the second information of the command information from the non-safety-related part is stored in the memory part.

[0155] In the case where the command information is damaged due to a stuck bit, a communication error, etc., it is possible to easily prevent the command information from accidentally matching with command information from other non-safety-related parts. Note that, in the case where the command information is constructed by combining the first information and the second information, it is unlikely that both pieces of information are damaged at the same time, so that it is possible to prevent inconvenience such as the information accidentally matching with other instructions.

[0156] Feature A4. The first diagnostic information included in the instruction from the non-safety-related part to the safety-related part is determined based on the command information; A robot control system described in any one of Features A1 to A3, wherein the safety-related part diagnoses whether the instruction has been received normally by comparing the first diagnostic information constituting the instruction from the non-safety-related part with the command information.

[0157] According to the configuration of this feature, the first diagnostic information (value) is determined (changes) according to the command information. When at least one of the command information and the first diagnostic information is damaged, the relationship between the two is lost, and it becomes possible to identify an abnormality in the instruction by diagnosis. With such a configuration, it is possible to suitably prevent erroneous switching due to an instruction (damaged) from a non-safety-related part.

[0158] In addition, when the first diagnostic information is added to the command information, the amount of information increases compared to when only the command information is used. In other words, the signal consisting of the command information and the first diagnostic information becomes longer, and the amount of information to be confirmed in the normal / abnormal diagnosis increases, improving the validity of the diagnosis result. This makes it possible to dramatically improve the reliability of switching (changing) the safety function by input from the non-safety-related part.

[0159] Feature A5. A robot control system described in any one of Features A1 to A4, in which the second diagnostic information sent from the safety-related part to the non-safety-related part in response to a request for the identification information from the non-safety-related part has a different configuration depending on which judgment criterion among the multiple judgment criteria is referenced in the judgment by the operation judgment part.

[0160] The identification information sent to the safety-related part in response to the safety-related part is accompanied by second diagnostic information. This second diagnostic information differs (variable value) according to the judgment criterion referenced by the operation judgment part of the safety-related part. In other words, it is possible to check not only for communication abnormalities from the second diagnostic information but also for whether the identification information is normal, and the reliability of the response can be improved with a simple configuration.

[0161] Feature A6. The second diagnostic information included in the response from the safety-related part to the non-safety-related part is determined based on the identification information; A robot control system described in any one of Features A1 to A5, wherein the non-safety-related part diagnoses whether the response has arrived normally by comparing the second diagnostic information and the identification information that constitute the response from the safety-related part.

[0162] According to this feature, the second diagnostic information (value) is determined (changes) according to the identification information. When at least one of the identification information and the second diagnostic information is damaged, the relationship between the two is lost, and it becomes possible to identify an abnormality in the response by diagnosis. This configuration contributes to further improving the reliability of the robot control system.

[0163] In addition, when the second diagnostic information is added to the identification information, the amount of information increases compared to when only the identification information is used. In other words, the signal consisting of the identification information and the second diagnostic information becomes longer, and the amount of information to be confirmed in the normal / abnormal diagnosis increases, improving the validity of the diagnosis result.

[0164] Feature A7. A robot control system described in any one of Features A1 to A6, wherein the second diagnostic information sent to the non-safety-related part in response to a request for identification information from the non-safety-related part after switching the judgment criterion among the multiple judgment criteria in response to the instruction from the non-safety-related part is created so as to be inconsistent with the first diagnostic information in the current instruction.

[0165] According to the configuration shown in this characteristic, the first diagnostic information and the second diagnostic information basically do not match when switching the safety function. Here, if the first diagnostic information is sent back as it is as the second diagnostic information due to an accidental error such as a stuck bit, the first diagnostic information and the second diagnostic information will match, and the error can be quickly found.

[0166] Feature A8. The command information and the identification information each include information indicating a criterion to be referenced by the operation determination unit among the multiple judgment criteria, and information indicating a sender of the command information and the identification information; A robot control system according to any one of Features A1 to A7, wherein the first diagnostic information included in the instruction from the non-safety-related part to the safety-related part is determined based on the command information included in the instruction, and the second diagnostic information included in the response from the safety-related part to the non-safety-related part is determined based on the identification information included in the response.

[0167] The first diagnostic information included in the instruction from the non-safety-related part and the second diagnostic information included in the response from the safety-related part are each determined based on the command information and the identification information, which include information indicating the sender. In other words, when switching the safety function, the first diagnostic information and the second diagnostic information basically do not match. Here, if the first diagnostic information is sent back as it is as the second diagnostic information due to an accidental error such as a stuck bit, the first diagnostic information and the second diagnostic information will match, and the above-mentioned overlooked error can be quickly discovered.

[0168] Feature A9. The judgment criteria include a force criterion for the force parameter and a speed criterion for the speed parameter, and a plurality of the force criterion and the speed criterion are defined; the safety-related unit stores combination information (scene number) indicating a combination of the force standard and the speed standard to be referred to in the determination by the motion determination unit, The robot control system according to any one of features A1 to A8, wherein the command information is configured to be information (scene number) correlated with the combination information.

[0169] As shown in Feature A8, when switching between multiple types of judgment criteria (force criteria, speed criteria), instead of specifying each judgment criterion individually, a combination of predefined criteria is specified, which makes it possible to prevent instructions from non-safety-related parts to safety-related parts from becoming complicated. This is a preferable configuration for increasing the number of tasks that a robot can perform while taking safety functions into consideration.

[0170] <Feature B group> Switching safety functions for each work scene The following feature B group is about the background technology of "Some robot control systems applied to robots such as industrial robots have safety-related parts that realize the safety functions of the robot and non-safety-related parts that perform drive control of the robot. For the safety-related parts, for example, a system has been proposed that forcibly stops the robot when it collides with an obstacle such as a person (see Patent Document 1), or that monitors the force (thrust) and speed of the robot while it is moving and forcibly stops the robot when it moves outside of safety standards." The feature B group is about the background technology of "In recent years, with the advancement of robot technology, the types of work that a robot can perform are also increasing. When a robot is used for various tasks, if the safety functions are uniform, it may be difficult to improve both safety and work efficiency. In consideration of such circumstances, the inventor of the present case We have devised a configuration for switching the safety functions of a robot. However, if the switching of the safety functions becomes frequent, the control load on the robot control system will increase excessively, and it is expected that the impact on the original function of the robot control system (i.e., the function of executing the drive control of the robot) will become significant. For example, if the safety functions are changed sequentially in response to changes in the position or orientation of the robot, the above-mentioned impact will be significant. Such an impact is undesirable because it leads to a decrease in the work efficiency of the robot. In addition, it is undesirable that the switching operation of the safety functions by the user is required, as it leads to a decrease in the convenience of the robot. Thus, in order to improve the safety and workability of the robot and promote the use of the robot, there is still room for improvement in the configuration related to the change of the safety functions. This was done in consideration of the background and issues that "

[0171] Feature B1. A robot control system (robot control system CS) having a motion judgment unit (logic unit X2) that judges the motion of the robot based on a safety-related input signal (a signal from a rotary encoder 46, a torque sensor 47, etc.) including a parameter correlated with at least one of the force and speed of the robot (robot 20) during work and a judgment criterion (reference value or reference range) for the parameter that is stored in advance, and a safety-related unit (safety-related unit X) that realizes the safety function of the robot by generating a safety-related output signal according to the judgment result, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; A plurality of work scenes in which the robot performs different tasks are defined as work scenes in which the robot performs tasks; A storage unit (memory of the control device 50) that stores the judgment criteria for the parameters in association with each of the work scenes; A scene identification unit (e.g., a function for executing a task monitoring process) that identifies the work scenes (scenes SN1 to SN9) of the robot; a criterion switching unit (a function of executing setting switching of a safety function in a safety FPGA) for switching the criterion for the parameters referred to by the operation judging unit to a criterion corresponding to the work scene identified by the scene identifying unit; A robot control system comprising:

[0172] It is preferable for a single robot to be able to handle multiple different tasks in order to promote the automation of manufacturing and other processes. However, if the safety functions of a robot are made uniform regardless of the work scene, it becomes difficult to improve both safety and work efficiency. In this regard, the configuration shown in this feature identifies the work scene and changes the monitoring criteria for each work scene. This contributes to improving the safety of the robot and improving work efficiency.

[0173] Here, in order to improve the safety of the robot, it is possible to configure the safety functions to change sequentially every time the operating state (position, orientation, speed, etc.) of the robot changes. However, such a configuration increases the control load on the robot control system, affecting the original function of the robot control system (robot drive control). In this regard, considering that the movement of the robot changes for each task, there is a clear technical significance in configuring the system to switch the judgment criteria for each task scene, as shown in this feature, in that it can improve safety while minimizing the impact on the original function of the robot control system.

[0174] Feature B2. Equipped with a drive control unit (drive control unit 51 of control device 50) that controls the drive of the robot according to a set operation program; The robot control system according to feature B1, wherein the scene identification unit identifies the work scene based on scene-related information included in the operation program being executed.

[0175] As shown in this feature, if the work scene can be identified based on the scene-related information included in the operation program, a configuration can be realized in which the robot control system can select the judgment criteria for each work scene by its own quick judgment. This can reduce the long waiting time required for switching safety functions and contribute to improving work efficiency.

[0176] Feature B3. The work scene includes a collaborative scene (e.g., scene SN3) in which the robot and a human collaborate, and a non-collaborative scene (e.g., scenes SN4 and SN5) in which the robot and a human do not collaborate; The robot control system according to feature B1 or B2, wherein the judgment criterion switching unit performs the switching so as to make the judgment criterion in the collaborative scene different from the judgment criterion in the non-collaborative scene.

[0177] As shown by this feature, when a robot's work scene includes collaborative and non-collaborative scenes, the safety and work efficiency of the robot can be improved in an optimal manner by setting different judgment criteria for those scenes.

[0178] Feature B4. The scene classification unit is capable of classifying the following work scenes: The robot control system according to any one of Features B1 to B3, wherein the judgment criterion switching unit performs the switching between a previous work scene and a subsequent work scene.

[0179] When the previous work scene is completed and a transition to the next work scene is made, the control load in the system can be more appropriately distributed by switching between the two scenes, compared to a configuration in which switching is made during work. Also, when moving to the next work scene, the situation is likely to change, and the distance to people, etc. will also change. Therefore, as shown in this feature, a configuration in which switching is made in preparation for the next scene is also preferable in terms of improving the safety of the robot.

[0180] Feature B5. The robot is configured to be brought to an emergency stop when the judgment result by the operation judgment unit indicates that the judgment criterion is exceeded; When the judgment standard is lowered with the change of the work scene, even if the judgment result by the operation judgment unit is that the judgment standard is exceeded, the robot is not brought to an emergency stop, and the movement of the robot is suppressed so as to forcibly lower the parameter without stopping the robot during a predetermined grace period after the lowering, The robot control system according to any one of features B1 to B4, wherein during the predetermined grace period, it is determined whether to stop the robot based on a decreasing trend of the parameter.

[0181] According to the configuration shown in this feature, even if the judgment criteria are lowered when the work scene is switched, the robot does not immediately stop (emergency stop). In other words, the robot does not suddenly stop due to the lowering of the judgment criteria. In such a situation, it is determined whether to stop the robot based on the decreasing trend of the parameter during a predetermined grace period. With this configuration, even if the safety function (judgment criteria) is changed with the switching of the work scene, the chances of the robot stopping erroneously can be reduced. In this way, suppressing the robot stopping erroneously is preferable in terms of improving the production efficiency of the robot 20.

[0182] For example, a target for parameter change during a specified grace period may be set, the change in the parameter may be checked during the specified grace period, and if the change does not reach the target, the robot may be stopped.

[0183] Feature B6. The robot is configured to be brought to an emergency stop when the judgment result by the operation judgment unit indicates that the judgment criterion is exceeded; Identifying the switching to the work scene and the determination criterion to be set when the next work scene occurs before the switching; A robot control system according to any one of features B1 to B4, which, when an excess of the judgment criterion set in the next work scene occurs during a specified period prior to switching to the next work scene, suppresses the movement of the robot to forcibly lower the parameter so that the excess is eliminated by the time the scene switches to the next work scene.

[0184] According to this characteristic configuration, a change in the work scene is identified (estimated or confirmed) in advance, and if it is confirmed in advance during a specified period before the change that the judgment criteria for the next work scene are exceeded, the movement of the robot is suppressed to forcibly lower the parameters. This prevents the judgment criteria from being exceeded at the timing of the change. With this configuration, even if the safety function (judgment criteria) is changed with the change in the work scene, the chances of the robot erroneously stopping can be reduced. In this way, suppressing erroneous stopping of the robot is preferable in terms of improving production efficiency by the robot 20.

[0185] Feature B7. A robot control system (robot control system CS) having a motion judgment unit (logic unit X2) that judges the motion of the robot based on a safety-related input signal (a signal from a rotary encoder 46, a torque sensor 47, etc.) including a parameter correlated with at least one of the force and speed of the robot (robot 20) during work and a judgment criterion (reference value or reference range) for the parameter that is stored in advance, and a safety-related unit (safety-related unit X) that realizes the safety function of the robot by generating a safety-related output signal according to the judgment result, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; A work area is defined for each work to be performed by the robot; A storage unit (a memory of the control device 50) that stores the judgment criteria for the parameters in association with each of the work areas; an area identification unit for identifying a working area of ​​the robot; a criterion switching unit (a function of executing setting switching of a safety function in a safety FPGA) for switching the criterion for the parameter referred to by the operation judging unit to a criterion corresponding to the work scene identified by the area identifying unit; A robot control system comprising:

[0186] It is preferable for one robot to take on multiple tasks in order to promote automation of manufacturing and the like. However, if the safety functions of the robot are made uniform regardless of the work area, it becomes difficult to improve both safety and work efficiency. In this regard, in the configuration shown in this feature, the work area is identified and the monitoring judgment criteria are changed for each work area. This contributes to improving the safety of the robot and improving work efficiency. Furthermore, this configuration has a clear technical significance in that it can improve safety while minimizing the impact on the original functions of the robot control system, compared to a configuration in which the safety functions are changed sequentially in response to changes in the position and orientation of the robot.

[0187] Feature B8. A robot control system (robot control system CS) having a motion judgment unit (logic unit X2) that judges the motion of the robot based on a safety-related input signal (a signal from a rotary encoder 46, a torque sensor 47, etc.) including a parameter correlated with at least one of the force and speed of the robot (robot 20) during work and a judgment criterion (reference value or reference range) for the parameter that is stored in advance, and a safety-related unit (safety-related unit X) that realizes the safety function of the robot by generating a safety-related output signal according to the judgment result, A drive control unit (drive control unit of the control device 50) is provided to control the robot so that the robot operates according to a predetermined time schedule in accordance with a set operation program, The predetermined time schedule specifies that a plurality of types of work are to be performed in sequence according to time or time of day, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; A storage unit (memory of the control device 50) that stores the parameter judgment criteria in association with the time or the time instant; A grasping unit that grasps the current time or the hour; a criterion switching unit (a function of executing setting switching of a safety function in a safety FPGA) that switches a criterion for the parameter referred to by the operation judging unit to a criterion corresponding to the predetermined time or the predetermined time when the time or the time grasped by the grasping unit becomes a predetermined time or a predetermined time for moving to a next task in the predetermined time schedule; A robot control system comprising:

[0188] It is preferable for one robot to take on multiple tasks in order to promote the automation of manufacturing and the like. However, if the safety functions of the robot are made uniform regardless of the time schedule, it becomes difficult to improve safety and work efficiency at the same time. In this regard, the configuration shown in this characteristic grasps the current time (e.g., the elapsed time from the start of the work routine) or hour, and changes the monitoring judgment criteria when a specified time or hour is reached. This can contribute to improving the safety of the robot and improving work efficiency.

[0189] Feature B9. A robot control system according to any one of Features B1 to B8, wherein the switching of the judgment criterion by the judgment criterion switching unit is not possible until one task being executed is completed.

[0190] Making the judgment criteria switchable as shown in feature B1 and the like is preferable in terms of improving the workability of the robot while taking into consideration the safety of the robot. However, when such a switching function is provided, the following new concerns arise. That is, if the judgment criteria are suddenly switched during task 1 due to an accidental reason or the like, an event may occur in which a movement that would normally be problem-free is caught by monitoring. This unnecessarily increases the chances of emergency stops of the robot, etc., and reduces work efficiency. Therefore, as shown in this feature, switching by the judgment criteria switching unit is not possible (for example, prohibited) until task 1 being executed is completed, and the occurrence of the above-mentioned event is suppressed, thereby realizing a practically preferable configuration.

[0191] Feature B10. The parameters include a parameter indicating a position of the robot during work; A robot control system according to any one of features B1 to B9, wherein when the judgment criterion switching unit switches the judgment criterion for at least one of the parameters of the force or the speed, the judgment criterion for the parameter indicating the position can also be switched at the same time.

[0192] By adding a position monitoring function and making it possible to switch the criteria for parameters indicating position together with the criteria for parameters indicating force and speed, it is possible to prevent the monitoring of the robot's force and speed from becoming excessively strict, which is preferable in terms of improving the work efficiency of the robot. [Explanation of symbols]

[0193] 10...factory, 20...robot, 31...AGV, 35...travel motor, 41...robot arm, 45...drive motor, 46...rotary encoder, 47...torque sensor, 50...control device, 51...drive control section, 52...monitoring control section, 60...teaching pendant, E1...stock area, E2...processing area, E3...accumulation area, E4...aisle, CS...robot control system, X...safety-related section, X1...input section, X2...logic section, X3...output section, Y...non-safety-related section.

Claims

1. A robot control system provided with a safety-related unit that has a motion determination unit that determines a motion of the robot based on a safety-related input signal including a parameter correlated to at least one of a force and a speed of the robot during work and a previously stored determination criterion for the parameter, and that realizes a safety function of the robot by generating a safety-related output signal in response to a result of the determination, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; A plurality of work scenes in which the robot performs different tasks are defined as work scenes in which the robot performs tasks; a storage unit that stores the parameter judgment criteria in association with each of the work scenes; a scene classification unit for classifying a work scene of the robot; a criterion switching unit for switching a criterion for the parameters referred to by the action determination unit to a criterion corresponding to the work scene identified by the scene identification unit; Equipped with the robot is brought to an emergency stop when the determination result by the operation determination unit indicates that the parameter exceeds the determination criterion, When the judgment standard is lowered with the change of the work scene, even if the judgment result by the operation judgment unit is that the parameter exceeds the judgment standard, the robot is not brought to an emergency stop, and the movement of the robot is suppressed so as to forcibly lower the parameter without stopping the robot during a predetermined grace period after the lowering, A robot control system that determines whether to stop the robot during the specified grace period based on a decreasing trend of the parameter.

2. a drive control unit that controls the drive of the robot according to a set operation program; The robot control system according to claim 1 , wherein the scene identification unit identifies the work scene based on scene-related information included in the operation program being executed.

3. a drive control unit that controls the drive of the robot according to a set operation program; In the operation program, the movement of the robot in the work scene is defined by a combination of a plurality of tasks, The robot control system according to claim 1 or 2, wherein the drive control unit switches the work scene when all of the tasks in the current work scene are completed.

4. A robot control system provided with a safety-related unit that has a motion determination unit that determines a motion of the robot based on a safety-related input signal including a parameter correlated to at least one of a force and a speed of the robot during work and a previously stored determination criterion for the parameter, and that realizes a safety function of the robot by generating a safety-related output signal in response to a result of the determination, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; A work area is defined for each work to be performed by the robot; a storage unit that stores the parameter judgment criteria in association with each of the work areas; an area identification unit for identifying a working area of ​​the robot; a criterion switching unit for switching a criterion for the parameter referred to by the operation judging unit to a criterion corresponding to the work area identified by the area identifying unit; Equipped with the robot is brought to an emergency stop when the determination result by the operation determination unit indicates that the parameter exceeds the determination criterion, when the judgment criterion is lowered in association with the change in the working area, even if the judgment result by the operation judgment unit indicates that the parameter exceeds the judgment criterion, the robot is not brought to an emergency stop, and the movement of the robot is suppressed so as to forcibly lower the parameter without stopping the robot during a predetermined grace period after the lowering, A robot control system that determines whether to stop the robot during the specified grace period based on a decreasing trend of the parameter.

5. A robot control system provided with a safety-related unit that has a motion determination unit that determines a motion of the robot based on a safety-related input signal including a parameter correlated to at least one of a force and a speed of the robot during work and a previously stored determination criterion for the parameter, and that realizes a safety function of the robot by generating a safety-related output signal in response to a result of the determination, a drive control unit that controls the robot to operate according to a predetermined time schedule in accordance with a set operation program; The predetermined time schedule specifies that a plurality of types of work are to be performed in sequence according to time or time of day, A plurality of candidates for the determination criteria for the parameters to be referred to by the operation determination unit are provided; a storage unit that stores a judgment criterion for the parameter in association with the time or the time instant; A grasping unit that grasps the current time or the hour; a criterion switching unit that switches a criterion for the parameter referred to by the operation judging unit to a criterion corresponding to the predetermined time or the predetermined hour when the time or the hour grasped by the grasping unit becomes a predetermined time or a predetermined hour for moving to a next task in the predetermined time schedule; Equipped with the robot is brought to an emergency stop when the determination result by the operation determination unit indicates that the parameter exceeds the determination criterion, when the judgment criterion is lowered as the predetermined time or the predetermined instant of time is reached, even if the judgment result by the operation judgment unit is that the parameter exceeds the judgment criterion, the robot is not brought to an emergency stop, and the movement of the robot is suppressed so as to forcibly lower the parameter without stopping the robot during a predetermined grace period after the lowering, A robot control system that determines whether to stop the robot during the specified grace period based on a decreasing trend of the parameter.

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