Control device and robot system

Abstract

Provided is a control device for controlling a robot, the control device including: an area setting unit that sets, in a work space, a safe movement area that includes a person or an object, such setting performed on the basis of information for identifying the person or the object in the work space; and a movement mode setting unit that sets, for the safe movement area, a movement mode that uses force control.

Description

Control Device and Robot System

[0001] The present disclosure relates to a control device and a robot system.

[0002] There is known a robot system configured to mount an end effector at the tip of an articulated robot and operate the articulated robot by force control to perform a predetermined operation. Further, as a robot having a force control function, there is known a collaborative robot configured to work in cooperation with a human. In this regard, Patent Document 1 describes a robot system that operates a robot in a safe mode in a non-detection area of a detector. Patent Document 2 describes a production system including a collaborative robot.

[0003] Japanese Unexamined Patent Application Publication No. 2017-7010, Japanese Unexamined Patent Application Publication No. 2018-51734

[0004] While the robot is moving, the contact force when the robot contacts an object tends to increase. Therefore, even in the case of a general robot and a collaborative robot having a force control function, there is a demand for reducing the contact force generated when the robot contacts the external environment. If the robot is operated at a low speed throughout the working space in order to reduce the contact force during contact, the cycle time of the operation becomes long and inefficient. A technology capable of achieving both the safety and efficiency of the operation by the robot is desired.

[0005] One aspect of the present disclosure is a control device that controls a robot, the control device including: a region setting unit that sets a safe operation region including a person or an object in the working space based on information that identifies the person or the object in the working space; and an operation mode setting unit that sets an operation mode by force control for the safe operation region.

[0006] These objects, features, and advantages of the present invention, as well as other objects, features, and advantages, will become more apparent from the detailed description of the typical embodiments of the present invention shown in the accompanying drawings.

[0007] This figure shows the equipment configuration of a robot system according to one embodiment. This is a functional block diagram of the robot system. This figure explains the function of setting the safe operating area by the area setting unit. This figure shows the state of the robot entering the safe operating area from outside the safe operating area. This is a graph for comparing the operation when the robot makes contact with an object in an area other than the safe operating area and performs stop control, and the operation when the robot makes contact with an object in the safe operating area and performs stop control. This is a graph for comparing the contact force when the robot makes contact with an object in an area other than the safe operating area and the contact force when the robot makes contact with an object in the safe operating area. This figure explains the control that moves the robot back in the opposite direction when the robot makes contact with an object. This figure explains the speed setting for the safe operating area. This is a flowchart showing the control that reduces the contact force.

[0008] Next, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, similar components or functional parts are given the same reference numerals. For ease of understanding, the scale of these drawings has been appropriately changed. Furthermore, the embodiments shown in the drawings are just one example of how to carry out the present invention, and the present invention is not limited to the illustrated embodiments.

[0009] Figure 1 is a diagram showing the equipment configuration of a robot system 100 according to one embodiment. As shown in Figure 1, the robot system 100 comprises a robot 10, a robot control device 20 that controls the robot 10, a teaching control panel 30 connected to the robot control device 20, a vision sensor 95, an image processing device 40 that controls the vision sensor 95, and a display device 90. The image processing device 40 and the display device 90 are connected to the robot control device 20. A screw tightening machine 60, which serves as an end effector, is attached to the flange 11 of the wrist portion of the robot 10 via a mounting plate 51. A force sensor (force detector) 70 for detecting external forces is attached between the flange 11 of the wrist portion and the mounting plate 51. In the above configuration, the robot system 100 can set the screw tightening machine 60 to a desired position and orientation using the robot 10, and make the robot 10 perform a force-controlled screw tightening operation based on the detected value detected by the force sensor 70.

[0010] As will be explained in detail below, the robot system 100 can identify targets (people or objects) in the workspace using the visual sensor 95, and based on the results, it can set a safe operating area within the workspace for the safe operation of the robot. Within the safe operating area, the robot system 100 operates the robot 10 in a predetermined force control mode. In this way, the robot system 100 achieves both safety and efficiency in the work.

[0011] As an example, robot 10 is assumed to be a 6-axis vertical articulated robot. However, various types of robots may be used as robot 10, such as horizontal articulated robots, parallel link robots, and dual-arm robots, depending on the task to be performed. Figure 1 shows an example configuration in which a screw tightening machine 60 is mounted as an end effector on robot 10, but various types of end effectors can be attached to robot 10 depending on the task.

[0012] The robot control device 20 controls the operation of the robot 10 according to an operation program or commands from the teaching control panel 30. The robot control device 20 may have a hardware configuration as a general computer, including a processor 21, memory (ROM, RAM, non-volatile memory, etc.), storage unit 22, operation unit, input / output interface, network interface, etc. (see Figure 2).

[0013] The teaching control panel 30 is used as an operating terminal for teaching the robot 10 and performing various settings. A teaching device consisting of a tablet terminal or the like may be used as the teaching control panel 30. The teaching control panel 30 may have a hardware configuration as a general computer, including a processor, memory (ROM, RAM, non-volatile memory, etc.), storage device, operation unit, display unit 31 (see Figure 2), input / output interface, network interface, etc.

[0014] The display device 90 provides a function to display various information related to the execution of the operating program. An information processing device such as a personal computer can be used as the display device 90. The display device 90 may have a hardware configuration as a general computer, including a processor, memory (ROM, RAM, non-volatile memory, etc.), storage device, operation unit, display unit 91 (Figure 2), input / output interface, network interface, etc.

[0015] The image processing device 40 controls the visual sensor 95 and has the function of performing various image processing on the image captured by the visual sensor. The image processing device 40 may be configured as a device dedicated to image processing, or it may be configured as a general-purpose information processing device such as a personal computer. The image processing device 40 may have a hardware configuration as a general computer, including a processor, memory (ROM, RAM, non-volatile memory, etc.), storage device, operation unit, display unit, input / output interface, network interface, etc.

[0016] The visual sensor 95 is positioned to monitor the entire workspace. The visual sensor 95 may be a two-dimensional camera that captures grayscale or color images, or a three-dimensional sensor that can acquire depth images or three-dimensional point clouds. Alternatively, the visual sensor 95 may have both two-dimensional camera and three-dimensional sensor functions. As a three-dimensional sensor, for example, a Time of Flight (TOF) camera that captures depth images using the optical time-of-flight method, or a stereo camera including two cameras can be used. In this embodiment, the visual sensor 95 may be pre-calibrated. In this case, the image processing device 40 may hold calibration data that defines the relative positional relationship between the visual sensor 95 and the world coordinate system (robot coordinate system fixed to the robot 10). This allows the position on the image captured by the visual sensor 95 to be converted to a position on the world coordinate system (robot coordinate system).

[0017] In this embodiment, an example configuration is described in which the image processing device 40 is arranged as a separate device from the robot control device 20 within the robot system 100. However, the entire function of the image processing device 40 may be incorporated into the robot control device 20.

[0018] The screw tightening machine 60 is, as an example, an angle-type screw tightening machine (nut runner). The screw tightening machine 60 comprises a main body 61 that includes a control unit 161 and a motor 162 (see Figure 2), and a head 62 connected to the tip of the main body 61. The head 62 holds a socket 65 as a tool. A screw 81 is held in the socket 65. The screw tightening machine 60 is connected to a robot control device 20, and, according to commands from the robot control device 20, tightens and fixes the screw 81 into the screw hole of the object (workpiece W).

[0019] The screw tightening machine 60 is attached to one side of the mounting plate 51, and the other side of the mounting plate 51 is attached to the flange 11 of the robot 10. In this configuration, the robot 10 can set the screw tightening machine 60 to a desired position and orientation and perform screw tightening work on the object.

[0020] The force sensor 70 is a six-axis force sensor that detects forces acting in the mutually orthogonal X, Y, and Z axis directions, as well as moments around each axis. In this embodiment, the external force acting on the robot 10 is detected by the force sensor 70, but instead of the force sensor 70, the external force may be detected by the detection values ​​of torque sensors provided on each axis of the robot.

[0021] Figure 2 is a functional block diagram of the robot system 100. As shown in Figure 2, the robot control device 20 includes an motion control unit 121, a force control unit 122, a force data processing unit 123, a contact determination unit 124, a stop control unit 125, a parameter adjustment unit 126, an operation mode setting unit 127, and a speed setting unit 128. The operation mode setting unit 127 includes a position control mode setting unit 129 and a force control mode setting unit 130. These functional blocks may also be functional elements realized by the processor 21 of the robot control device 20 executing software.

[0022] The robot control device 20 includes a storage unit 22. The storage unit 22 is a storage device, such as a non-volatile memory or a hard disk drive. The storage unit 22 stores various setting information, including an operation program for controlling the robot 10, force control parameters, operation parameters, and contact detection thresholds.

[0023] The motion control unit 121 controls the movement of the robot 10 according to the motion program or according to commands from the teaching control panel 30. The robot control device 20 includes a servo control unit (not shown) that performs servo control on the motors 111 of each axis according to the commands for each axis generated by the motion control unit 121.

[0024] The force data processing unit 123 provides a function to calculate external forces (force and moment) acting on a predetermined part of the robot 10 (such as the screw tightening machine 60) based on the detected values ​​of the force sensor 70. The position and orientation of the force sensor 70 can be calculated from the position and orientation of the tip of the robot 10's wrist in the coordinate system and the relative position information of the force sensor 70 with respect to the tip of the wrist. Based on the position, orientation, and detected values ​​of the force sensor 70, the force data processing unit 123 can calculate the magnitude and direction of the force and moment in any coordinate system pre-set for the robot 10. Note that the function of the force data processing unit 123 may be implemented by a device separate from the robot control device 20.

[0025] The force control unit 122 performs force control based on the force information calculated by the force data processing unit 123 and predetermined force control parameters. The force control may include impedance control, damping control, or hybrid control. The motion control unit 121 works in conjunction with the force control unit 122 to manage the operation performed by the force control.

[0026] The contact determination unit 124 compares the external force acting on the robot 10 with a threshold for contact determination, and determines that the robot has come into contact with the external environment (person or object) if the external force exceeds the threshold. The stop control unit 125 provides a function to slow down and stop the robot 10 when the contact determination unit 124 determines that the robot 10 has come into contact with the external environment.

[0027] The parameter adjustment unit 126 provides a function to automatically adjust force control parameters while the robot 10 is performing force-controlled operations. For example, the parameter adjustment unit 126 can search for appropriate force control parameters (pressing force, force control gain, etc.) by repeatedly having the robot 10 perform force-controlled operations (operations involving position and posture correction in screw tightening operations, precision fitting operations, etc.) while checking the detected values ​​(force and moment) of the force sensor 70 and changing the force control parameters.

[0028] The operation mode setting unit 127 provides functions for setting the operation mode of the robot 10. The functions of the operation mode setting unit 127 include controlling the robot 10 to operate in position control mode in the robot 10's normal operating range, and controlling the robot 10 to operate in force control mode in a safe operating range that allows the robot 10 to operate more safely than in the normal operating range. In addition, the functions of the operation mode setting unit 127 include the function of setting operation parameters in position control mode, and the function of setting operation parameters (force control parameters) in force control mode.

[0029] The operation mode setting unit 127 includes a position control mode setting unit 129 and a force control mode setting unit 130. The position control mode setting unit 129 provides a function for setting operation parameters in position control mode. The position control mode setting unit 129 may be configured to set operation parameters in position control mode according to an operation program or pre-set setting information, or it may have a function to accept specification of operation parameters from the user. The force control mode setting unit 130 provides a function for setting operation parameters (force control parameters) in force control operation mode. The force control mode setting unit 130 may be configured to set operation parameters (force control parameters) in force control mode according to an operation program or pre-set setting information, or it may have a function to accept specification of force control parameters from the user.

[0030] The speed setting unit 128 provides a function to set speed limits for the robot in the normal operating range and the safe operating range, respectively. The speed setting unit 128 may have a function to automatically set the speed limits, or it may have a function to set the speed limits based on the operation program or other setting information. Alternatively, the speed setting unit 128 may have a function to accept input of speed limits from the user.

[0031] The image processing device 40 comprises a visual data processing unit 141 and a storage unit 142. The visual data processing unit 141 has the function of performing various image processing based on image information acquired by the visual sensor 95. The functions of the visual data processing unit 141 may include the function of identifying various objects such as workpieces and robots, as well as people, from two-dimensional images or depth images obtained by the visual sensor 95. For example, the visual data processing unit 141 may have the function of detecting objects by pattern matching between the image of the object in the captured image and a model pattern, or the function of object detection using deep learning. As the function of object detection using deep learning, methods such as a CNN (convolutional neural network) based object detector capable of outputting bounding boxes and corresponding class labels from the input image, or semantic segmentation that performs class classification on a pixel-by-pixel basis may be used.

[0032] Furthermore, the visual data processing unit 141 has a region setting unit 143 that sets a safe operating area within the work space that is safer than the normal operating area, according to the object (object or person) identified from the image.

[0033] The screw tightening machine 60 includes a motor 162 for rotating the socket 65 and a control unit 161 for driving and controlling the motor 162. The control unit 161 drives and controls the motor 162 according to commands from the operation control unit 121 (including the specification of operation parameters, etc.). The control unit 161 may be composed of a microcomputer chip incorporating, for example, a CPU, memory (ROM, RAM, non-volatile memory, etc.).

[0034] Referring to Figure 3, the function of setting the safe operating area by the area setting unit 143 will be explained. In Figure 3, it is assumed that a workpiece W, which is to be screwed, is placed on the workbench 2. The visual sensor 95 continuously images and monitors the work space. When the area setting unit 143 identifies the workpiece W in the image, it sets a certain area including the workpiece W as the safe operating area. The safe operating area including the workpiece W will be called safe operating area A (see Figure 3). Furthermore, when a person is identified in the image, the area setting unit 143 sets a certain area including the person as a safe operating area with a different level of safety than safe operating area A. The safe operating area including the person will be called safe operating area B (see Figure 3). Note that the safe operating area can be any three-dimensional area that includes the identified object, and may be a sphere or a similar three-dimensional shape as shown in Figure 3, or a rectangular parallelepiped shape.

[0035] The area setting unit 143 provides the robot control device 20 with information regarding the type and location of the set safe operating area A and safe operating area B (area setting information). The visual data processing unit 141 (area setting unit 143) constantly updates the safe operating area according to the image information updated by the visual sensor 95 constantly monitoring the work space, and continues to provide this information to the robot control device 20. In other words, the area setting information is transmitted to the robot control device 20 in real time and is continuously updated. For example, when a person PE moves within the work space, the safe operating area B also moves along with the person's movement, and this information is transmitted to the robot control device 20 in real time.

[0036] The operation mode setting unit 127 operates the robot 10 in a normal position control mode (hereinafter referred to as the position control mode) while the robot 10 (a predetermined control point such as the tip of a tool) is in an area other than the safe operation area, and switches the operation mode of the robot 10 to a predetermined force control mode when the robot 10 enters the safe operation area. The force control mode in the safe operation area will also be referred to as the force control approach mode below. The force control approach mode is an area that reduces the impact (contact force) of contact when the robot 10 (a predetermined control point) comes into contact with an object (a person or object) during the process of moving to the target position (in this example, the workpiece W placed on the workbench 2), and allows it to stop quickly, compared to the position control mode.

[0037] Furthermore, the operation mode setting unit 127 (force control mode setting unit 130) sets the force control parameters so that the safety levels differ between the safe operation area A, which includes an object as illustrated in Figure 3, and the safe operation area B, which includes a person. Specifically, the operation mode setting unit 127 (force control mode setting unit 130) sets the force control parameters so that the safety level in the safe operation area B, which includes a person, is higher than that in the safe operation area A, which includes only an object.

[0038] Table 1 below shows an example of setting force control parameters for safe operating area A and safe operating area B by the operation mode setting unit 127 (force control mode setting unit 130). The settings in Table 1 are configured such that for safe operating area B, contact is detected more sensitively than in safe operating area A, and the robot can be stopped more quickly. For safe operating area A, contact detection does not need to be as sensitive as in safe operating area B, and the robot can be stopped more slowly than in safe operating area B.

[0039]

[0040] In the setting example of the force control parameters according to Table 1 above, since the contact determination threshold value in the safe operation area B is set to a value lower than that in the safe operation area A, in the safe operation area B, the contact between the robot and the target is detected more sensitively than in the safe operation area A, and it is possible to shift to stop control or the like more quickly. Also, in the safe operation area B, the acceleration / deceleration rate and the speed gain are set to values larger than those in the safe operation area A. Therefore, in the safe operation area B, when contact with the target is detected, the robot 10 can be decelerated and stopped more quickly.

[0041] As shown in FIG. 4, assume a situation where the robot 10 moves from an area C other than the safe operation areas A and B toward the workpiece W which is the target position in order to perform a screwing operation. In such a case, the operation mode setting unit 127 can recognize that the robot 10 (control point) has entered the safe operation area A based on the position information of the robot 10 (control point) and the area setting information. The operation mode setting unit 127 switches the operation mode of the robot 10 to the force control approach mode at the timing when the robot 10 (control point) enters the safe operation area A. The force control parameters in the force control approach mode in this case are the settings for the safe operation area A.

[0042] Thereby, it is possible to quickly detect that the robot 10 (tool tip) has contacted the workpiece W and to mitigate the impact (contact force) at the time of contact.

[0043] After the control for detecting the contact with the workpiece W and mitigating the impact (contact force) at that time is performed as described above, the operation mode setting unit 127 shifts the operation mode of the robot 10 to the force control mode for the screwing operation. That is, the force control parameters such as the traveling speed, the pressing force, and the force control gain of the robot 10 are set to the settings for the screwing operation, and the screwing operation is executed.

[0044] In addition, when the robot 10 enters the safe operation area B during the process of moving toward the workpiece W, the operation mode of the robot 10 will be set to the force control approach mode with the force control parameters for the safe operation area B. In this case, when the robot 10 comes into contact with a person, the robot 10 will quickly stop in a state where the impact (contact force) during contact is further reduced. After performing such a stop operation during contact, the robot 10 can start moving toward the target (workpiece W) again.

[0045] Fig. 5 shows a graph for comparing the operations when the robot 10 performs stop control by contacting an object in an area outside the safe operation area and the operations when the robot performs stop control by contacting an object in the safe operation area (safe operation area A or B). The graphs 201 and 202 shown on the left side of Fig. 5 respectively show the position and speed of the robot (control point) in an area outside the safe operation area (i.e., in the position control mode). Also, the graphs 211 and 212 shown on the right side of Fig. 5 respectively show the position and speed of the robot (control point) in the safe operation area (i.e., in the force control approach mode). In each of the left and right graphs in Fig. 5, the scale on the left vertical axis represents speed, the scale on the right vertical axis represents position, and the horizontal axis represents time. In each of the left and right graphs, the left end of the horizontal axis (time axis) is the time point when the robot contacts the object.

[0046] As can be understood from the comparison between the solid-line graph 202 and the graph 212, in the force control approach mode, the robot 10 can stop in time T ２０ (about 0.1 second) after contact is detected. In contrast, in the position control mode, the robot 10 takes time T １０ (about 0.28 second) from contact to stop. Therefore, it can be understood that in the force control approach mode, the robot can stop more quickly when contacting than in the case of the position control mode.

[0047] Furthermore, as can be seen from the comparison between the dashed graph 201 and graph 211, the amount the robot moves (indentation) from the time contact is detected until it stops is '-0.0432' in the force-controlled approach mode, while it is '-0.0465' in the position-controlled mode. This shows that the indentation is smaller in the force-controlled approach mode.

[0048] Figure 6 shows graphs comparing the contact force when the robot 10 makes contact with an object in an area outside the safe operating area and the contact force when the robot 10 makes contact with an object in the safe operating area (safe operating area A or B). Graph 221 on the left in Figure 6 shows the change in contact force when the robot makes contact with an object in an area outside the safe operating area (i.e., in position control mode), while graph 222 on the right shows the change in contact force when the robot makes contact with an object in the safe operating area (i.e., in force control approach mode). As shown in the figures, the overshoot of the contact force during contact in position control mode is 195 N (absolute value), while the overshoot of the contact force during contact in force control approach mode is reduced to 42 N (absolute value). Therefore, it can be understood that the impact (contact force) during contact can also be reduced by setting the force control parameters as described above in the safe operating area.

[0049] The robot control device 20 may have a function to record position data and external force data of the robot 10 and display graphs like those shown in Figures 5 and 6 on the display unit 91 of the display device 90 or the display unit 31 of the teaching operation panel 30. This allows the user to analyze the graphs and consider the values ​​of the parameters that should be set.

[0050] The robot control device 20 may also have the following functions, from the viewpoint of further improving its performance regarding safe operation in the safe operation area (such as sensitivity of contact detection and speed of stopping upon contact).

[0051] The operation mode setting unit 127 may, for example, set the force control approach mode so that the robot 10 can detect contact more sensitively in the force control approach mode than in the position control mode, by not applying filtering to the output (external force) of the force sensor 70. By making such a setting, the responsiveness of the contact determination unit 124 to changes in the output (external force) of the force sensor 70 can be improved.

[0052] Furthermore, the operation mode setting unit 127 may also perform control to reverse the robot 10 when it comes into contact with an object, as a control to reduce the impact (contact force) when the robot 10 comes into contact with an object. This control will be explained with reference to Figure 7. As shown in the upper part of Figure 7, suppose the robot 10 (control point) moves toward the target object (workpiece W) (downward in Figure 7) in the safe operation area A and comes into contact with the target object (workpiece W). At the moment the operation mode setting unit 127 detects contact between the robot 10 and the object, it issues a position command to move the robot 10 in the opposite direction to the direction of movement. As a result, as shown in the lower part of Figure 7, the robot 10 moves backward in the opposite direction (upward in Figure 7) at the moment it comes into contact with the object. With this type of control, the impact (maximum contact force) when the robot 10 comes into contact with the object (workpiece W) can be further reduced.

[0053] Next, the function of the speed setting unit 128 will be explained with reference to Figure 8. The speed setting unit 128 has the function of setting speed limit values ​​for the robot 10 in areas other than the safe operating area and in each of the safe operating area. In Figure 8, we assume that the speed limit in area C other than the safe operating areas A and B (i.e., in position control mode) is set to, for example, 2000 mm / s.

[0054] The speed setting unit 128 sets the speed limit in the safe operating area A to 250 mm / s, for example. In this case, as shown in Figure 8, when the robot 10 enters the safe operating area A from area C to perform screw tightening work, the operating mode of the robot 10 is set to force-controlled approach mode, and the maximum speed of the robot 10 is limited to 250 mm / s. Therefore, in this case, if the speed at which the robot 10 enters the safe operating area A exceeds 250 mm / s, the robot 10 will decelerate to 250 mm / s and operate. With this type of control, it is possible to further reduce the contact force when the robot 10 comes into contact with an object within the safe operating area A, and to further shorten the time until the robot 10 stops.

[0055] For the safe operating area B, which includes people, the speed setting unit 128 sets a stricter speed limit. For example, the speed setting unit 128 sets the speed limit in the safe operating area B to 100 mm / s. This further reduces the contact force when the robot 10 comes into contact with a person within the safe operating area B, and also further shortens the time it takes for the robot 10 to stop.

[0056] Figure 9 is a flowchart showing the control flow for reducing contact force in the robot system 100 having the functions described above. The process in Figure 9 is mainly performed under the control of the processor 21 of the robot control device 20.

[0057] First, the operator teaches the force control parameters required in the normal force control mode (Step S1). Here, for example, force control parameters (such as forward speed, target force, and force control gain) required for screw tightening work using force control are set. At this point, the robot 10 begins moving toward the target (workpiece W). Simultaneously, the visual sensor 95 begins monitoring the workspace, and area setting information is transmitted to and updated in real time by the robot control device 20 (Step S2).

[0058] The operation mode setting unit 127 determines whether the robot 10 (control point) is in the safe operation area based on the area setting information (step S3). If the robot 10 is not yet in the safe operation area (S3: NO), operation in position control mode continues (step S4), and processing from step S2 continues.

[0059] When it is determined that the robot 10 is in a safe operating area (S3: YES), the operation mode setting unit 127 switches the operation mode of the robot 10 to the force control approach mode (step S5).

[0060] Furthermore, the operation mode setting unit 127 determines whether the speed of the robot 10 exceeds the speed limit value in the safe operation area (step S6). If the speed of the robot 10 exceeds the speed limit value in the safe operation area (S6: YES), the operation mode setting unit 127 reduces the speed of the robot 10 to the speed limit value (step S7). If the speed of the robot 10 does not exceed the speed limit value in the safe operation area (S6: NO), the process proceeds to step S8.

[0061] In step S8, the contact detection unit 124 determines contact between the robot 10 and the external environment. If contact between the robot 10 and the external environment is detected (S8: YES), the robot 10 operates to decelerate in force-controlled approach mode and moves to a safer position in the opposite direction of travel (step S9). As described above, this operation reduces the impact when the robot comes into contact with a person or object, thereby increasing safety.

[0062] If no contact is detected between the robot 10 and the external environment (S8: NO), or if there is a force control operation to be performed after the robot 10 has performed the deceleration and retraction operation in step S9 (S10: YES), the operation mode setting unit 127 switches the operation mode of the robot 10 to a force control mode for a predetermined operation, and allows the robot 10 to perform the predetermined operation by force control (step S11). If the predetermined operation by force control is completed, or if there is no predetermined operation by force control (S10: NO), this process ends.

[0063] Furthermore, the flow from the contact determination in step S8 to the execution of a predetermined operation by force control in step S11 is as follows, if the safe operating area determined in step S3 is safe operating area A which includes the target workpiece W. The robot control device 20 recognizes that the object it has contacted is workpiece W, taking into account that the safe operating area is safe operating area A, and if necessary, the current position of the robot 10. Then, after performing the deceleration and retraction operation in step S9, the robot control device 20 checks whether there is a force control operation to be performed next (S10: YES), and then starts the predetermined operation by force control (step S11).

[0064] As described above, according to this embodiment, when having a robot perform a predetermined force control task, it is possible to enhance the safety of the work while avoiding a decrease in work efficiency in order to enhance safety. In other words, according to this embodiment, it is possible to achieve both improved safety and increased work efficiency when using a robot.

[0065] In the embodiments described above, it should be understood that not all of the functional blocks in the functional block diagram shown in Figure 2 are essential.

[0066] Furthermore, the functional arrangement shown in the functional block diagram in Figure 2 is illustrative, and there are various possible variations in the arrangement of the functional blocks in order to realize the functions of the embodiment described above. For example, some or all of the functions of the image processing device 40 may be located within the robot control device 20. In Figure 2, it is also possible that some of the functions within the robot control device 20 (for example, the speed setting unit 128) are located on the teaching operation panel 30 side. In addition, in Figure 2, some of the functional blocks located within the robot control device 20 may have their functions integrated.

[0067] In the above-described embodiment, a configuration was explained in which an object is identified from image information of a visual sensor and a safe operating area is set based on the identification result. On the other hand, in application examples where the position of the workpiece to be worked on is fixed, there may also be configuration examples in which the safe operating area set at least around the workpiece is set based on the known position of the workpiece.

[0068] Alternatively, information from various sensors (position sensors, proximity sensors, human detection sensors, etc.) placed within the robot system may be used to identify objects or people within the workspace. For example, the position of a workpiece being transported on a conveying device may be determined based on information from position sensors (sensors that detect the position of the conveyor) placed on the conveying device.

[0069] The configuration of the above embodiment has the aspect of being able to enhance safety by mitigating the impact on people or objects (workpieces) during contact, by introducing an operating mode called the force control approach mode to a predetermined force control operation by the robot. Since the force control approach mode is an operating mode that is applied in the safe operating area, it is also possible to avoid a decrease in work efficiency.

[0070] The configuration of the above-described embodiment can be applied as a configuration for improving safety in various industrial machine systems.

[0071] In the functional block diagram of Figure 2, each functional block described as a function of an image processing device, a robot control device, or a teaching control panel may be realized by one or more processors of these devices executing various software stored in a memory device, or in this case, part of the function may be made up of hardware such as discrete circuits (i.e., the functional block may be realized by a combination of a processor and discrete circuits), or the functions shown in the functional block diagram may be realized by a hardware-based configuration such as an ASIC (Application Specific Integrated Circuit).

[0072] Computer programs for performing various processes such as control to reduce contact force in the above-described embodiment (Figure 9), or computer programs for performing processes in each part of the processor of each device such as a robot control device, may be provided in the form of program products recorded on various computer-readable recording media (for example, semiconductor memories such as ROM, EEPROM, and flash memory, magnetic recording media, or optical recording media such as CD-ROM and DVD-ROM).

[0073] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. Furthermore, these embodiments can be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0074] The following further notes apply to the above embodiments and modifications. (Note 1) A control device (20) for controlling a robot, comprising: an area setting unit (143) for setting a safe operating area including a person or object within the working space based on information identifying a person or object within the working space; and an operating mode setting unit (127) for setting an operating mode by force control for the safe operating area. (Note 2) The control device (20) according to Note 1, further comprising a visual data processing unit (141) for acquiring the information identifying a person or object from image information obtained by imaging the working space with a visual sensor. (Note 3) The control device (20) according to Note 1 or 2, further comprising a speed setting unit (128) capable of setting the speed of the robot within the safe operating area. (Note 4) The control device (20) according to any one of Notes 1 to 3, wherein the operating mode setting unit (127) sets an operating mode of force control corresponding to the identified object for the safe operating area. (Note 5) The control device (20) according to Note 1, wherein the area setting unit (143) sets a plurality of safe operating areas based on the information, and the operation mode setting unit (127) sets an operation mode for force control corresponding to each identified object for the plurality of safe operating areas. (Note 6) The control device (20) according to Note 5, further comprising a speed setting unit (128) capable of setting the speed of the robot for each of the plurality of safe operating areas. (Note 7) The control device (20) according to Note 5 or 6, wherein the plurality of safe operating areas include a first safe operating area including an object and a second safe operating area including a person. (Note 8) The control device (20) according to any one of Notes 1 to 7, wherein the operation mode by force control in the safe operating area includes an operation mode that can reduce the overshoot of the contact force when the robot comes into contact with the external environment. (Note 9) The control device (20) according to any one of Notes 1 to 8, wherein the operation mode setting unit (127) sets the operation mode of the robot to position control mode in areas other than the safe operation area.(Note 10) The control device (20) according to any one of the following: a contact determination unit (124) that determines contact between the robot and the external environment based on the output of a force detector mounted on the robot; and a stop control unit (125) that decelerates and stops the robot when contact is detected by the contact determination unit, wherein the operation mode setting unit (127) increases the sensitivity of the contact determination in the safe operation area compared to when it is outside the safe operation area. (Note 11) The control device (20) according to Note 10, wherein the operation mode setting unit (127) applies at least one of the following to the safe operation area: setting the contact determination threshold used for determining contact to a value lower than the value when it is outside the safe operation area, or not performing filtering on the output of the force detector. (Note 12) The control device (20) according to Note 10 or 11, wherein the operation mode setting unit (127) sets at least one of the acceleration / deceleration and speed gain to a value greater than the value outside the safe operation area so that the robot can decelerate more quickly when it comes into contact with the external environment than when it is outside the safe operation area. (Note 13) The control device (20) according to any one of Notes 10 to 12, wherein the operation mode setting unit (127) outputs a command to reverse the direction of travel of the robot immediately after detecting contact between the robot and the external environment in the force control operation mode of the safe operation area, thereby reducing the contact force when the robot comes into contact with the external environment. (Note 14) The control device (20) according to any one of Notes 10 to 13, wherein the operation mode setting unit (127) switches the operation mode of the robot to a predetermined force control operation mode according to the work purpose after detecting contact between the robot and the external environment in the force control operation mode of the safe operation area. (Note 15) The control device (20) according to any one of Notes 1 to 14, wherein the information used to identify a person or object is information that is updated in real time.(Note 16) A robot system (100) comprising: a robot (10); a control device (20) for controlling the robot (10); a region setting unit (143) for setting a safe operating area in the working space that includes a person or object based on information that identifies a person or object in the working space; and an operating mode setting unit (127) for setting an operating mode by force control for the safe operating area. (Note 17) The robot system (100) according to Note 16, further comprising a visual data processing unit (141) for acquiring the information that identifies a person or object from image information obtained by imaging the working space with a visual sensor.

[0075] 2 Workbench 10 Robot 11 Flange 20 Robot control device 21 Processor 22 Memory unit 30 Teaching control panel 31 Display unit 40 Image processing device 51 Mounting plate 60 Screw tightening machine 61 Main body 62 Head unit 65 Socket 70 Force sensor 81 Screw 90 Display device 91 Display unit 95 Visual sensor 100 Robot system 111 Motor 121 Motion control unit 122 Force control unit 123 Force data processing unit 124 Contact determination unit 125 Stop control unit 126 Parameter adjustment unit 127 Operation mode setting unit 128 Speed ​​setting unit 129 Position control mode setting unit 130 Force control mode setting unit 141 Visual data processing unit 142 Memory unit 143 Area setting unit 161 Control unit 162 Motor

Claims

1. A control device for controlling a robot, comprising: an area setting unit that sets a safe operating area including a person or object within the working space based on information that identifies a person or object within the working space; and an operating mode setting unit that sets an operating mode by force control for the safe operating area.

2. The control device according to claim 1, comprising a visual data processing unit that acquires information for identifying a person or object from image information obtained by imaging the workspace with a visual sensor.

3. The control device according to claim 1 or 2, further comprising a speed setting unit capable of setting the speed of the robot in the safe operating area.

4. The control device according to any one of claims 1 to 3, wherein the operation mode setting unit sets an operation mode for force control corresponding to the identified object for the safe operation area.

5. The control device according to claim 1, wherein the area setting unit sets a plurality of safety operating areas based on the information, and the operation mode setting unit sets an operation mode for force control corresponding to each identified object for the plurality of safety operating areas.

6. The control device according to claim 5, further comprising a speed setting unit capable of setting the speed of the robot for each of the multiple safe operating areas.

7. The control device according to claim 5 or 6, wherein the plurality of safety operating areas include a first safety operating area including an object and a second safety operating area including a person.

8. The control device according to any one of claims 1 to 7, wherein the operating mode by force control in the safe operating area includes an operating mode that can reduce the overshoot of the contact force when the robot comes into contact with the external environment.

9. The control device according to any one of claims 1 to 8, wherein the operation mode setting unit sets the operation mode of the robot to position control mode in areas other than the safe operation area.

10. A control device according to any one of claims 1 to 9, comprising: a contact determination unit that determines contact between the robot and the external environment based on the output of a force sensor mounted on the robot; and a stop control unit that decelerates and stops the robot when contact is detected by the contact determination unit, wherein the operation mode setting unit increases the sensitivity of the contact determination in the safe operation area compared to when it is outside the safe operation area.

11. The control device according to claim 10, wherein the operating mode setting unit applies at least one of the following: setting the contact determination threshold used for determining contact in the safe operating area to a value lower than the value outside the safe operating area; or not performing filtering on the output of the force detector.

12. The control device according to claim 10 or 11, wherein the operation mode setting unit sets at least one of the acceleration / deceleration and speed gain to a value greater than the value outside the safe operation area, so that when the robot comes into contact with the external environment in the operation mode of force control in the safe operation area, the robot can decelerate more quickly than when it is outside the safe operation area.

13. The control device according to any one of claims 10 to 12, wherein the operation mode setting unit reduces the contact force when the robot comes into contact with the external environment by outputting a command to reverse the direction of travel of the robot immediately after detecting contact between the robot and the external environment in the operation mode of force control in the safe operation area.

14. The control device according to any one of claims 10 to 13, wherein the operation mode setting unit switches the operation mode of the robot to a predetermined force control operation mode according to the work purpose after contact between the robot and the external environment is detected in the force control operation mode in the safe operation area.

15. The control device according to any one of claims 1 to 14, wherein the information used to identify a person or object is information that is updated in real time.

16. A robot system comprising: a robot; a control device for controlling the robot; a region setting unit for setting a safe operating area in the working space that includes a person or object based on information identifying a person or object in the working space; and an operating mode setting unit for setting an operating mode by force control for the safe operating area.

17. The robot system according to claim 16, further comprising a visual data processing unit that acquires information for identifying a person or object from image information obtained by imaging the workspace with a visual sensor.

Images