Robot System

Abstract

This robot system (100, 500) comprises a robot (10, 520) and a robot control device (50, 530) for performing control so as to cause the robot (10, 520) to execute prescribed work on the basis of the result of detection of a subject to be detected by a sensor, the robot control device (50, 530) being provided with an abnormality-detection-time processing unit (153, 636) for, in accordance with sensing of an abnormality pertaining to the detection operation carried out by the sensor, controlling the robot (10, 520) so as to return to the position of a time point at which the detection serving as the source of the abnormality was carried out and then stop.

Description

[Technical field]

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

[0002] Conventionally, a robot system is known that includes a transport device that transports an article, a robot that performs a predetermined task on the transported article, a robot control device, and an imaging device that detects the article, etc. (see, for example, Patent Document 1).

[0003] Patent Document 2 relates to a control device for a work robot that performs specified tasks on a production line, and describes "a control device for a work robot that has the function, when a monitoring device that monitors the working status of a work device that performs specified tasks on a workpiece recognizes an abnormality in the working status, of returning the work device to the position where the abnormality was recognized and resuming the work from that position" (page 2, bottom right column, lines 14 to 20). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-188508 A [Patent Document 2] Japanese Patent Application Publication No. 62-278610 Summary of the Invention [Problem to be solved by the invention]

[0005] Consider the teaching and adjustment of a robot system including a transport device, a robot that performs a predetermined task on a transported object, a robot control device, and an imaging device as described above. Generally, in such a robot system, the imaging device takes images of the object or the transport device and detects its position, and the robot performs the task while following the object. In this process, it is difficult for an operator to check whether the processing at each position is being performed without problems. Therefore, when a problem occurs, teaching and adjustment are time-consuming, and the system takes a long time to start up. [Means for solving the problem]

[0006] One aspect of the present disclosure includes a robot and a robot control device that controls the robot to perform a predetermined task based on a detection result of a sensor for a detection target, and the robot control device includes an abnormality detection processing unit that controls the robot to return to a position at which the detection causing the abnormality was detected and stop the robot in response to detection of an abnormality related to the detection operation by the sensor. the abnormality detection processing unit activates the sensor while the robot has returned to the position at which the abnormality was detected and is stopped, and causes a display unit to display an output result of the sensor. It is a robot system. Effect of the Invention

[0007] According to the above configuration, the robot returns to the position where it was when the cause of the abnormality was detected and stops, so the operator can teach and adjust the problem area without having to carry out the burdensome task of moving the robot to the problem area. This significantly reduces the effort required for teaching and adjustment when a problem occurs in the robot system, and shortens the time required for starting up the robot system.

[0008] These and other objects, features and advantages of the present invention will become more apparent from the detailed description of exemplary embodiments of the invention that are illustrated in the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1]FIG. 1 is a diagram illustrating a configuration of a robot system according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the hardware configuration of a robot control device and a higher-level control device. [Diagram 3] FIG. 2 is a functional block diagram of a robot control device and a host control device. [Figure 4] 4 is an example of a reference image when detection is performed by an imaging device. [Diagram 5] 13 is a flowchart of alignment control using an imaging device. [Figure 6] 11 is an example of a captured image during alignment control. [Figure 7] 11 is a flowchart showing a process to be performed when an abnormality occurs. [Figure 8] FIG. 13 is a diagram illustrating an example of displaying information regarding the contents of an abnormality. [Figure 9] FIG. 13 is a diagram illustrating a configuration of a robot system according to another embodiment. [Figure 10] FIG. 10 is a functional block diagram of a robot control device in the robot system of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, similar components or functional parts are given similar reference symbols. To facilitate understanding, the scale of these drawings is appropriately changed. In addition, the form shown in the drawings is one example for implementing the present invention, and the present invention is not limited to the illustrated form.

[0011] FIG. 1 is a diagram showing the configuration of a robot system 100 according to an embodiment. As shown in FIG. 1, the robot system 100 includes a robot 10 having a hand 30 mounted on the arm tip, a robot control device 50 for controlling the robot 10, a transport device (a conveyor 25 and a conveyor control device 20) for transporting an article, three imaging devices 71-73, and a host control device 60. The robot control device 50 and the conveyor control device 20 are connected to the host control device 60, which controls the robot control device 50 and the conveyor control device 20 in an integrated manner so that a predetermined task is performed in the robot system 100. As shown in FIG. 1, a teaching device 40 may be connected to the robot control device 50.

[0012] The host controller 60 is, for example, a PLC (Programmable Logic Controller), and performs overall control of the operation timings of the robot controller 50 and the conveyor controller 20 in accordance with a control program for controlling the operation sequence.

[0013] The imaging devices 71-73 are connected to the robot controller 50 and operate under the control of the robot controller 50. In this embodiment, the robot controller 50 has a function of controlling each imaging device and a function of performing image processing on image data captured by each imaging device. The imaging devices 71-73 may be cameras that capture grayscale or color images, or stereo cameras or three-dimensional sensors that can capture distance images or three-dimensional point clouds. In this embodiment, each imaging device is a camera that captures two-dimensional images.

[0014] The conveyor control device 20 controls the driving of the motor 26 of the conveyor 25, thereby controlling the transportation of the workpieces by the conveyor 25.

[0015] The teaching device 40 is used, for example, to adjust teaching contents and programs. The teaching device 40 may be, for example, a teaching operation panel, a tablet terminal, a smartphone, or other information processing device.

[0016] In the robot system 100, when an abnormality is detected by the imaging devices 71-73, the robot control device 50 controls the robot 10 to return to the position at which the abnormality was detected and stop the robot 10. This allows the operator to make adjustments at the position where the problem occurred without moving the robot.

[0017] The configuration of this embodiment is applicable to a robot system capable of executing various processes (detection, judgment, etc.) using a visual sensor, but here, as an example, a configuration will be described in which the robot 10 grasps a workpiece 91 leaned against a stand 2 and attaches it to a workpiece 81 being transported on a conveyor 25. As an example, the workpiece 91 is a vehicle door, and the workpiece 81 is a vehicle body to which the door is to be attached. The robot 10 repeatedly performs the task of attaching the workpiece 91 to the workpieces 81 that are transported one after another on the conveyor 25 in the direction of the arrow in Fig. 1, during which the imaging devices 71-73 repeatedly perform imaging and detection operations of the detection target.

[0018] 2 is a diagram showing an example of the hardware configuration of the upper control device 60 and the robot control device 50. The upper control device 60 may have a configuration as a general computer in which a memory 62 (ROM, RAM, non-volatile memory, etc.), a display unit 63, an operation unit 64 consisting of an input device such as a keyboard (or software key), an input / output interface 65, etc. are connected to a processor 61 via a bus. The robot control device 50 may have a configuration as a general computer in which a memory 52 (ROM, RAM, non-volatile memory, etc.), an input / output interface 53, an operation unit 54 including various operation switches, etc. are connected to a processor 51 via a bus. The teaching device 40 may also have a configuration as a general computer having a processor, a memory, a display unit, an operation unit, various input / output interfaces, etc.

[0019] FIG. 3 is a functional block diagram of the robot control device 50 and the upper control device 60. As shown in FIG. 3, the robot control device 50 has an operation control unit 151 that controls the operation of the robot 10 (and the hand 30) in accordance with a command from the teaching device 40 or an operation program 155, an image processing unit 152 that controls the imaging devices 71-73 and performs image processing on the captured images, and an abnormality detection time processing unit 153 that controls the robot 10 to return to the position at the time when the abnormality was detected in response to the detection of an abnormality by any of the imaging devices 71-73. The information recording unit 154 acquires and records the position of the robot 10 at the time when the abnormality was detected and other information. The abnormality detection time processing unit 153 also has a function of sending a signal indicating that an abnormality was detected to the upper control device 60 in response to the detection of an abnormality by any of the imaging devices 71-73.

[0020] The upper controller 60 includes a control unit 161 that controls the operation sequences of the robot controller 50 and the conveyor controller 20 in accordance with a control program 164, and an abnormality processing unit 162 that controls the conveyor 25 to return to the position at the time the abnormality was detected in response to receiving a signal indicating that the above-mentioned abnormality has been detected from the robot controller 50. An information recording unit 163 acquires and records the position of the conveyor 25 at the time the abnormality was detected and other information.

[0021] Here, an example of the target detection operation by the imaging devices 71-73 performed while the robot 10 is performing a predetermined task will be described. The imaging device 71 is a fixed camera, and when the robot 10 grasps a workpiece 81 leaned against the stand 2, it captures an image of the state only once and detects any misalignment in the grasp.

[0022] The imaging devices 72 and 73 are fixed to the tip of the arm of the robot 10. The imaging directions of the imaging devices 72 and 73 are set so as to capture images of the vicinity of the attachment position when the robot 10 attaches the workpiece 91 to the workpiece 81. The imaging devices 72 and 73 repeatedly capture images while the robot 10 moves the workpiece 91 and attaches it to the workpiece 81.

[0023] The following describes the control of aligning the workpiece 91 with respect to the workpiece 81 using the imaging device 72 or 73, which is executed as part of such an attachment operation. Here, the case where an image captured by the imaging device 72 is used will be described. In the alignment control, when the robot 10 moves the workpiece 91 to a position where it can be attached to the workpiece 81, the imaging device 72 captures an image of that state, and control is performed to adjust the position of the robot 10.

[0024] 4 shows an image captured by the imaging device 72 under normal conditions when the robot 10 is in a position where the workpiece 91 can be attached to the workpiece 81 (here, the workpiece 91 is moved vertically downward to a position where the pins of the workpiece 91 can be inserted into the holes of the workpiece 81). Since this image is an image when the robot 10 is in the correct position, it will hereinafter also be referred to as a reference image 261.

[0025] The image processing unit 152 of the robot control device 50 has a function of detecting the feature amounts of characteristic portions that are predetermined characteristic parts of the workpieces 81 and 91. The image processing unit 152 also has a function of calculating the difference between the feature amount of the workpiece 81 and the feature amount of the workpiece 91 as a relative amount. The image processing unit 152 generates a command to operate the robot 10 based on the calculated relative amount.

[0026] In the robot system 100, the position of the workpiece 91 is aligned with respect to the workpiece 81 being transported by the conveyor 25, based on images captured by the imaging devices 72 and 73. Specifically, the position is aligned when inserting a pin (not shown) of the workpiece 91 (door) into holes 82a and 83a (see FIG. 6) of the protrusions 82 and 83 of the workpiece 81 (car body).

[0027] Before the robot 10 performs an actual task, the image processing unit 152 calculates the relative position amount in the reference image 261 according to the following procedures (A1) to (A3). (A1) The image processing unit 152 detects the upper surface of the protrusion 82 as a first characteristic portion for detecting the position of the workpiece 81, and detects the upper surface of the protrusion 92 of the workpiece 91 as a second characteristic portion for detecting the position of the workpiece 91. Note that as the characteristic portion, a part of the workpiece, a pattern formed on the surface of the workpiece, a line or a figure written on the surface of the workpiece, etc. may be adopted. As a method for detecting the characteristic portion, a base image serving as a reference for each of the workpieces 81, 91 may be prepared in advance. The characteristic portion in the image captured by the imaging device 72 can be detected by a method such as template matching using the base image and the image captured by the imaging device 72.

[0028] (A2) Next, the image processing unit 152 detects a first feature amount related to the position of the first feature portion and a second feature amount related to the position of the second feature portion. A screen coordinate system 252 is set in the image captured by the imaging device 72. The screen coordinate system 252 is a coordinate system when an arbitrary point in the image is set as the origin. The screen coordinate system 252 has a u axis and a v axis that are orthogonal to each other, and corresponds to the visual sensor coordinate system of the imaging device 72. The feature amount related to the position in this embodiment is the coordinate value of the u axis and the coordinate value of the v axis of the screen coordinate system 252 in the image. The image processing unit 152 can detect the positions of the set points P1 and P2 set in the feature portion based on the feature portion detected in the reference image 261. The image processing unit 152 detects the coordinate value (u1b, v1b) of the set point P1 in the screen coordinate system 252 as the first feature amount. Moreover, the feature amount detection unit detects the coordinate values ​​(u2b, v2b) of the setting point P2 in the screen coordinate system 252 as a second feature amount.

[0029] (A3) Next, the image processing unit 152 calculates a relative amount between the first feature amount and the second feature amount in the reference image. The image processing unit 152 calculates a relative position amount as a relative amount to control the position of the robot 10. The relative position amount is the difference between the first feature amount and the second feature amount. For example, the image processing unit 152 calculates the difference (u1b-u2b, v1b-v2b) between the coordinate value of the first feature amount and the coordinate value of the second feature amount as the relative position amount. The calculated relative position amount in the reference image 261 is stored as a reference relative position amount.

[0030] In this way, the image processing unit 152 can calculate the relative position amount in the reference image 261. In this embodiment, it is assumed that the relative position amount in the reference image 261 is calculated in advance and stored in the storage unit.

[0031] 5 shows a flowchart of the alignment control. This process is executed under the control of the processor 51 of the robot control device 50. After the robot control device 50 performs control to bring the workpiece 91 close to a position where it can be attached to the workpiece 81, in step S101, the operation control unit 151 causes the imaging device 72 to capture images of the workpieces 81 and 91.

[0032] 6 shows image 262 captured by imaging device 72 in step S101. Image 262 includes an image of the top surface of protrusion 82, which is a first characteristic portion, and an image of the top surface of protrusion 92, which is a second characteristic portion. In image 262, workpiece 91 is shifted toward the positive side of the u-axis of screen coordinate system 252 with respect to workpiece 81, as indicated by arrow 201.

[0033] In step S102, the image processing unit 152 detects a first characteristic portion and a second characteristic portion of the image 262 captured by the imaging device 72. Here, the top surface of the protrusion 82 of the workpiece 81 is detected as the first characteristic portion, and the top surface of the protrusion 92 of the workpiece 91 is detected as the second characteristic portion.

[0034] Next, in step S103, the image processing unit 152 detects a first feature amount and a second feature amount in the image captured by the imaging device 72. The image processing unit 152 detects the coordinate values ​​(u1m, v1m) of the setting point P1 in the screen coordinate system 252 as the first feature amount related to the first feature portion, and calculates the coordinate values ​​(u2m, v2m) of the setting point P2 in the screen coordinate system as the second feature amount related to the second feature portion.

[0035] Next, in step S104, the image processing unit 152 calculates the difference between the first feature amount and the second feature amount as a relative position amount. The relative position amount in the image 262 captured by the imaging device 72 is the difference between the coordinate value of the first feature amount and the coordinate value of the first feature amount (u1m-u2m, v1m-v2m).

[0036] Next, in step S105, the image processing unit 152 calculates a difference in a relative position amount between the relative position amount in the image 262 and the relative position amount in the reference image 261. The difference in the relative position amount can be expressed as values ​​related to the u-axis and v-axis, respectively, as [(u1m-u2m)-(u1b-u2b), (v1m-v2m)-(v1b-v2b)].

[0037] Next, in step S106, it is determined whether the difference in the relative position amount is within a predetermined range. If the difference in the relative position amount is within the predetermined range (S120: YES), it is considered that the alignment of the workpiece 91 with respect to the workpiece 81 is completed, and this process ends.

[0038] On the other hand, if the difference in the relative position amount is outside the predetermined range (S120: NO), it can be determined that the workpiece 91 has not reached the desired position with respect to the workpiece 81. In this case, the process proceeds to step S107.

[0039] In step S107, the image processing unit 152 sets a driving method for the robot 10 based on the difference in the relative position amount. The image processing unit 152 sets the movement direction and movement amount of the robot in the reference coordinate system. In this embodiment, the movement direction of the position of the robot 10 with respect to the difference in the relative position amount is determined in advance based on the relative positional relationship between the screen coordinate system 252 and the reference coordinate system of the robot 10. For example, the movement direction of the robot position with respect to the positive or negative value of the u axis of the screen coordinate system is determined in the reference coordinate system as follows. When the difference in the relative position amount with respect to the u axis is a positive value, the movement direction of (1,1,0) is determined using the coordinate values ​​of the X-axis, Y-axis, and Z-axis of the reference coordinate system. When the difference in the relative position amount with respect to the y axis is positive, the movement direction of (0,0,1) is determined using the coordinate values ​​of the X-axis, Y-axis, and Z-axis of the reference coordinate system.

[0040] Furthermore, a calculation method for the movement amount of the robot's position relative to the difference in the relative position amount is determined, for example, as follows. The movement amount of the robot's position in the direction corresponding to the u axis can be a value obtained by multiplying the value related to the u axis ((u1m-u2m)-(u1b-u2b)) by a predetermined coefficient. Also, the movement amount of the robot's position in the direction corresponding to the v axis can be a value obtained by multiplying the value related to the v axis ((v1m-v2m)-(v1b-v2b)) by a predetermined coefficient. In this way, the movement amount of the robot 10 can be calculated in the direction corresponding to each axis of the screen coordinate system 252.

[0041] Next, in step S108, the robot 10 is driven based on the movement direction and amount of movement of the robot position calculated as described above. The image processing unit 152 generates a movement command for driving the robot 10 based on the movement direction and amount of movement of the robot position. The image processing unit 152 sends the movement command to the operation control unit 151. The operation control unit 151 controls the position of the robot 10 based on the movement command. Then, the processing from step S115 is repeated. By such control, the position of the workpiece 91 can be gradually brought closer to the desired position.

[0042] The image processing unit 152 has a function of detecting an abnormality in the detection operation by any of the imaging devices 71 to 73. As examples of abnormality detection, the following situations may occur. (B1) There is a continuous state in which the detection target (e.g., a characteristic part) is not detected in the image. (B2) When capturing images of a moving detection target continuously, a situation may arise in which the position of the detected detection target is not continuous (is in an unexpected position).

[0043] 7 is a flowchart showing an abnormality detection process executed when an abnormality in detection by an imaging device is detected in the robot system 100. In the abnormality detection process, the flow shown in steps S1 to S6 is executed under the control of the processor 51 of the robot control device 50, and the flow shown in steps S7 to S10 is executed under the control of the processor 61 of the upper control device 60.

[0044] It is assumed that an abnormality in detection by any of the imaging devices 71-73 is detected due to the occurrence of the above-exemplified situation (B1) or (B2) (step S1).

[0045] In step S2, the robot controller 50 (abnormality detection processing unit 153) sends to the upper controller 60 a signal indicating that an abnormality has been detected.

[0046] Next, the abnormality detection processing unit 153 (information recording unit 154) acquires the current position (position A) of the robot 10 (step S3). The position of the robot 10 also includes the posture. Then, the robot control device 50 (abnormality detection processing unit 153) decelerates and stops the robot 10 to stop it safely (step S4).

[0047] Next, the robot controller 50 (abnormality detection processing unit 153) judges whether the robot 10 has stopped (step S5). The robot controller 50 (abnormality detection processing unit) waits for the robot to stop (S5: NO).

[0048] When the robot stops (S5: YES), the robot control device 50 (abnormality detection processing unit 153) moves the robot 10 to position A where it was at the time the abnormality was detected, and stops the robot 10 there.

[0049] When receiving a signal indicating the detection of an abnormality from the robot control device 50, the upper control device 60 (information recording unit 163) acquires the current conveyor position (position B) information (step S7). Next, the upper control device 60 (abnormality processing unit 162) decelerates and stops the conveyor 25 for safety reasons (step S8).

[0050] Next, the host controller 60 (abnormality processing unit 162) judges whether the conveyor 25 has stopped (step S9). The host controller 60 (abnormality processing unit 162) waits until the conveyor 25 has stopped (D9: NO). When the conveyor 25 has stopped (S9: YES), the host controller 60 (abnormality processing unit 162) moves the conveyor 25 to position B, which is the position when the abnormality occurred, and stops the conveyor 25 (step S10). By the above process, when an abnormality is detected in the detection operation of the imaging device, the robot 10 and the conveyor 25 can be returned to the positions at the time when the abnormality was detected.

[0051] In addition to returning the robot 10 and the conveyor 25 to the position at which the abnormality was detected, the robot system 100 may further perform one or more of the following actions (C1) to (C3). (C1) When each device constituting the robot system has returned to the point in time when the abnormality was detected, each imaging device captures an image and presents the captured image. (C2) Present information about the content of the anomaly. (C3) Present information about the operating conditions of the robot system at the time an anomaly is detected.

[0052] The above-mentioned operation (C1) can be realized by the abnormality detection time processing unit 153 operating each of the imaging devices 71-73 via the image processing unit 152 to display the captured images on the display unit 41 of the teaching device 40 after the robot 10 and the conveyor 25 have returned to the point at which the abnormality was detected. Since the abnormal state can be reproduced in such captured images, the operator can accurately adjust the position of the robot 10 in the operation program, adjust the operation timing of the robot 10, or adjust the installation position of the imaging devices while observing such captured images.

[0053] The above operation (C2) can be realized, for example, by the information recording unit 154 of the robot control device 50 cooperating with the image processing unit 152 or the operation control unit 151 to acquire information on the contents of the abnormality when the abnormality is detected, and the abnormality detection processing unit 153 displays the information on the contents of the abnormality acquired by the information recording unit 154 on the teaching device 40. FIG. 8 shows an example of a case where the abnormality detection processing unit 153 displays the contents of the abnormality when an abnormality in the detection of the imaging device is detected on the display screen (display unit 41) of the teaching device 40. In this example, an error display screen 145 is displayed that displays a message that the imaging device (camera #2 in this example) has not detected the target object as the cause of the abnormality. In this case, the operator can use the information on the contents of the abnormality presented here as a clue to accurately adjust the position of the robot 10 in the operation program, adjust the operation timing of the robot 10, adjust the installation position of the imaging device, and the like.

[0054] That is, by providing the operator with information regarding the details of the abnormality in this manner, it becomes possible to efficiently make adjustments to recover from the abnormality.

[0055] As an example of the above operation (C3), the information recording unit 154 of the robot control device 50 may be configured to record information about the operating conditions of the robot 10 (e.g., the position, posture, operating speed, etc. of the robot) at the time when an abnormality is detected. Furthermore, the information recording unit 163 of the upper control device 60 may be configured to record information about the operating conditions (position, speed, etc.) of the conveyor 25 at the time when an abnormality is detected. Information about the operating conditions of the robot 10 and the conveyor 25 may also be displayed, for example, on the display unit 41 of the teaching device 40. Such information about the operating conditions can also make adjustments by the operator more efficient.

[0056] Note that the presentation of information by the above operations (C1) to (C3) may be performed on a device having a display unit in the robot system 100 (for example, the upper control device 60) in addition to the above examples.

[0057] As described above, according to this embodiment, the robot returns to the position at which the cause of the abnormality was detected and stops, so the operator can teach and adjust the robot at the problem location without having to carry out the burdensome task of moving the robot to the problem location. This significantly reduces the effort required for teaching and adjustment when a problem occurs in the robot system, and shortens the time required for starting up the robot system.

[0058] Although the present invention has been described using exemplary embodiments, those skilled in the art will understand that modifications and various other changes, omissions, and additions can be made to the above-described embodiments without departing from the scope of the present invention.

[0059] It should be understood that the configuration of the robot system 100 shown in Fig. 1 is an example, and not all of the components are essential components. For example, a system configuration in which the conveyor 25 and the conveyor control device 20 are omitted from the robot system 100 is also possible.

[0060] Although the above embodiment relates to a robot system that detects an object using an imaging device as a visual sensor to perform a predetermined task, the present invention may be applied to a robot system having other types of sensors (proximity sensors, distance sensors, etc.) for detecting objects. When such other types of sensors are used in a robot system, the output results of the sensors are presented in the above operation (C1).

[0061] The configuration shown in the above embodiment, in which the robot or each movable body of the robot can be returned to the position when the problem occurred, various adjustments can be made, and the time required to start up the system can be shortened, can be applied to robot systems of various forms.

[0062] Here, another embodiment will be described with reference to Figs. 9 and 10. The embodiment shown here relates to a robot system configured to be able to correct the position of the robot with respect to the working space by detecting a marker arranged in the working space with a visual sensor mounted on the robot. Fig. 9 is a diagram showing the device configuration of a robot system 500. The robot system 500 includes a machine tool 510, a robot 520, a robot control device 530 for controlling the robot 520, and a transport device 581 for transporting the robot 520 and the robot control device 530. The robot 520 is mounted on the transport device 581 and placed at a predetermined position in front of the machine tool 510, and performs a predetermined task such as loading / unloading a work object (hereinafter referred to as a workpiece) into the machine tool 510. That is, the robot system 500 is configured as an automation system that automates the loading / unloading of a workpiece into the machine tool 510 by the robot 520. The transport device 581 is, for example, a dolly or an AGV (Automated Guided Vehicle).

[0063] The teaching device 550 is connected wirelessly or by wire to the robot control device 530, and is used to teach the robot 520. During actual operation of the robot system 500, the control program created using the teaching device 550 is registered in the robot control device 530, so the teaching device 550 may be omitted from the robot system 500.

[0064] 9, when the robot 520 performs an operation such as loading / unloading a workpiece, the position of the transport device 581 on which the robot 520 is mounted changes. Therefore, the robot 520 needs to be configured to measure the positional deviation of the robot 520 with respect to the machine tool 510 and perform the operation correctly with respect to the machine tool 510. For this reason, a visual sensor 571 is mounted on the arm tip 521 of the robot 520, and the robot 520 (robot control device 530) is configured to detect the positional deviation of the robot 520 with respect to the working space (machine tool 510) using the visual sensor 571 and correct the positional deviation to perform the operation.

[0065] The teaching device 550 provides a function of creating a program (hereinafter, such a program is also referred to as a measurement program) that measures the three-dimensional position of a marker 504 set at a predetermined position in the working space (machine tool 510) by using a visual sensor 571 mounted on an arm tip 521 of the robot 520 and measures the positional deviation of the robot 520 from a desired position in the working space. A control program including the measurement program created using the teaching device 550 is registered in the robot control device 530, and thereafter, the robot 520 (robot control device 530) can operate to detect the positional deviation of the robot 520 from a desired position in the working space, correct the position, and execute a predetermined task.

[0066] The visual sensor 571 may be a two-dimensional camera or a three-dimensional position detector. In this embodiment, the visual sensor 571 is a two-dimensional camera. The visual sensor 571 is connected to the robot control device 530. The robot control device 530 has a function for controlling the visual sensor 571, a function for performing various image processing on the image captured by the visual sensor 571, and the like. In addition, calibration data including data indicating the position of the visual sensor 571 with respect to the robot 520 is stored in advance in the memory of the robot control device 530.

[0067] Fig. 10 is a functional block diagram of the robot control device 530. As shown in Fig. 10, the robot control device 530 includes a storage unit 631 that stores a control program and other various information, an operation control unit 632 that controls the operation of the robot 520 according to the control program, a marker position measurement unit 633, a relative position calculation unit 634, a measurement accuracy evaluation unit 635, and an abnormality detection time processing unit 636.

[0068] The marker position measuring unit 133 measures the three-dimensional position of the marker 504 using the visual sensor 571. In this embodiment, as an example, the marker position measuring unit 633 measures the position of the marker 504 by a stereo measurement method using the visual sensor 571 as a two-dimensional camera. That is, the marker position measuring unit 633 changes the position of the visual sensor 571 consisting of a two-dimensional camera, captures images of the same marker 504 from two different positions, and calculates the three-dimensional position of the marker 504. This method has the advantage that a position measuring system can be realized at low cost by using a relatively inexpensive two-dimensional camera. Note that other methods known in the art for measuring the position of a marker (also called a target mark or visual marker) may be used.

[0069] The storage unit 631 stores calibration data indicating the position of the two-dimensional camera (visual sensor 571) based on a coordinate system (mechanical interface coordinate system) set on the arm tip 521 of the robot 520. Meanwhile, the robot control device 530 (marker position measurement unit 633) can grasp the position and posture of the arm tip 521 when the robot 520 is in motion. Therefore, the robot control device 530 (marker position measurement unit 633) can associate the sensor coordinate system at the time of imaging by the two-dimensional camera (visual sensor 571) with the robot coordinate system by converting the mechanical interface coordinate system into the robot coordinate system according to the motion of the robot 520. This enables the marker position measurement unit 633 to obtain the position of the target (marker 504) as a three-dimensional position in the robot coordinate system.

[0070] The relative position calculation unit 634 calculates the relative position between the working space (machine tool 510) and the robot 520 (in other words, the amount of deviation from the intended position of the robot 520 with respect to the working space) based on the measured marker positions.

[0071] The operation control unit 632 controls the robot 520 so that the robot 520 performs the task in a correct position and posture corrected from the specified position and posture based on the calculated relative positional relationship between the workspace and the robot (the amount of deviation from the intended position of the robot 520 relative to the workspace).

[0072] The measurement accuracy evaluation unit 635 has a function of evaluating the accuracy of the measurement result obtained when the marker position measurement unit 633 measures the position of one marker 504 .

[0073] The marker position measuring unit 633 may be configured to increase the number of markers to be measured when the measurement accuracy is evaluated as low by the measurement accuracy evaluating unit 635. As an example, when performing measurement using three markers, the following procedure is performed. The three markers are arranged at positions around the teaching point. The position and orientation of the coordinate system (work space coordinate system) are grasped by assuming that the measured position of the first marker is the origin position, the measured position of the second marker is the position in the X-axis direction, and the measured position of the third marker is on the XY plane.

[0074] After grasping the relative positional relationship between the robot 520 and the working space (machine tool 510) using the above-mentioned method, the robot control device 530 causes the robot 1 to perform a specified task (such as loading / unloading a workpiece into the machine tool 510) while performing a correction operation so that the positional relationship between the robot 520 and the working space is maintained at a desired positional relationship.

[0075] When an abnormality caused by a correction operation using the detection result of the marker is detected during the process in which the robot 1 performs a predetermined task, the abnormality detection processing unit 636 controls the robot 520 to return the visual sensor 571 to the imaging position of the marker (i.e., the position where the detection that caused the abnormality was performed) and stop it. Here, an abnormality caused by the correction operation is, for example, a case in which the robot 520 cannot place a workpiece in a correct position when placing it (seating error, etc.). In this way, when an abnormality caused by the correction operation is detected, the robot 520 (visual sensor 571) automatically returns to the imaging position (i.e., the position where the image for generating the correction operation was performed), so that the operator can quickly and easily make adjustments (parameter adjustments, etc.) related to the detection function of the marker.

[0076] The robot system 100 described with reference to FIGS. 1 to 8 above and the robot system 500 described with reference to FIGS. 9 and 10 above can be considered as a robot system that includes a robot and a robot control device that controls the robot to perform a specified task based on the detection result of a sensor for a detection target, and the robot control device includes an abnormality detection processing unit that, when an abnormality related to the detection operation by the sensor is detected, controls the robot to return to the position at which the detection causing the abnormality was made and stop the robot.

[0077] 3 and 10 are merely examples, and various examples of functional allocation are possible. For example, a configuration is also possible in which a visual sensor control device having the function of the image processing unit 152 in the above-described embodiment is disposed as a device separate from the robot control device.

[0078] The functional blocks of the robot control device and the higher-level control device shown in Figures 3 and 10 may be realized by the processors of these devices executing various software stored in a storage device, or may be realized by a hardware-based configuration such as an ASIC (Application Specific Integrated Circuit).

[0079] Programs for executing various processes such as the alignment control of FIG. 5 and the process upon abnormality detection of FIG. 7 in the above-described embodiment can be recorded on various computer-readable recording media (e.g., semiconductor memories such as ROM, EEPROM, and flash memory, magnetic recording media, and optical disks such as CD-ROM and DVD-ROM). [Explanation of symbols]

[0080] 10. Robot 20 Conveyor control device 25 Conveyor 30 Hands 40 Teaching device 41 Display section 50 Robot control device 51 Processors 52 Memory 53 Input / Output Interface 54 Operation section 60 Upper control device 61 processors 62 Memory 63 Display section 64 Operation section 65 Input / Output Interface 71, 72, 73 Imaging device 81, 91 Work 100 Robot System 151 Motion control section 152 Image processing section 153 Abnormality detection processing unit 154 Information Recording Section 155 Operation Program 161 Control Unit 162 Abnormality Processing Unit 163 Information Recording Department 164 Control Program 500 Robot System 504 Marker 510 Machine tools 520 Robot 530 Robot control device 550 Teaching device 571 Visual Sensor 631 Storage section 632 Motion control section 633 Marker Position Measurement Unit 634 Relative Position Calculation Unit 635 Measurement Accuracy Evaluation Department 636 Abnormality detection processing unit

Claims

1. Robots and a robot control device that controls the robot to perform a predetermined task based on a detection result of the sensor with respect to the detection target, the robot control device includes an abnormality detection processing unit that, in response to detection of an abnormality relating to a detection operation by the sensor, controls the robot to return to a position at which the abnormality was detected and stop the robot there; the abnormality detection processing unit activates the sensor while the robot has returned to and stopped at the position at which the abnormality was detected, and causes a display unit to display an output result of the sensor. Robot system.

2. the robot control device causes the robot to perform the predetermined task while detecting the detection target using the sensor; The robot system according to claim 1 , wherein the abnormality detection processing unit controls the robot to return to a position at which the abnormality was detected and stop the robot in response to the abnormality being detected in the detection operation by the sensor.

3. A conveying device that conveys an article; A host control device that controls the transport device and the robot control device, The abnormality detection processing unit further outputs a signal indicating that the abnormality has been detected to the upper control device in response to the abnormality being detected; 3. The robot system according to claim 1, wherein the host control device includes an abnormality processing unit that, in response to receiving the signal, controls the transport device to return to the position at which the abnormality was detected and stop the transport device.

4. the sensor is an imaging device; The robot system according to claim 1 , wherein the output result is an image captured by the imaging device.

5. The robot system according to claim 1 , wherein the abnormality detection processing section causes the display section to display information relating to a content of the abnormality in response to the detection of the abnormality.

6. The robot system according to claim 1 , wherein the abnormality detection processing section causes the display section to display information regarding an operating condition of the robot at a time when the abnormality was detected.

7. A teaching device connected to the robot control device for teaching the robot, The robot system according to claim 1 , wherein the display unit is provided in the teaching device.

8. the sensor is a visual sensor mounted on the robot; the robot control device is configured to execute a correction operation to correct a position of the robot with respect to the workspace by detecting one or more markers arranged in the workspace with the visual sensor; the abnormality is caused by the correction operation, The robot system according to claim 1 , wherein the abnormality detection processing unit controls the robot to return to a position where the visual sensor detected the marker in response to detection of the abnormality.

9. An operation control unit that controls the robot to perform a predetermined task based on the detection result of the sensor for the detection target; an abnormality detection processing unit that, in response to detection of an abnormality relating to the detection operation by the sensor, controls the robot to return to a position at which the abnormality was detected and stop the robot, the abnormality detection processing unit activates the sensor while the robot has returned to and stopped at the position at which the abnormality was detected, and causes a display unit to display an output result of the sensor. Robot control device.

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