Robot control device, robot system and robot control program

Abstract

A robot control device is provided with which it is possible to perform a tightening work using a tightener efficiently and with high accuracy. The robot control device controls a robot and causes the robot to perform the tightening work using a tightener, and is provided with a storage unit, an acquisition unit, a setting unit, and a control unit. The storage unit stores, in association with each other, information about the tightener and a parameter related to performing the tightening work. The acquisition unit acquires, based on an output of a tightener detection sensor, information about a tightener with which the tightening work is to be performed. A setting unit acquires, based on the acquired information about the tightener, the parameter associated with the information about the tightener from the storage unit and sets the parameter.The control unit controls the robot based on the set parameter.

Description

Area

[0001] The present invention relates to a robot control device, a robot system and a robot control program. background

[0002] In recent years, a screw tightening robot system (robot system) that causes a robot to perform tightening work through a tightener, such as a screw, a bolt, and a nut, has been widely used in various industries. Examples of screw tightening robots used for such a screw tightening robot system include a robot in which a nut driver (screw tightening device) and the like are attached to the arm tip (hand) of a multi-joint robot, or a robot equipped with a force sensor (so-called "force sensor") without using a nut driver for screw tightening.

[0003] For example, a screw tightening robot performs screw tightening (tightening work) on a workpiece (or work target) running on a production line during a production process. It should be noted that, for example, when tightening a large number of bolts, a worker (operator, user) manually or automatically sets the screw tightening parameters, replaces a suitable socket wrench on the robot, and then performs the screw tightening work. In this case, it is necessary to appropriately adjust the parameters that define the relationship between the force applied to the workpiece and the behavior of the robot when performing the screw tightening (tightening work) through a force controller on the robot.

[0004] In the prior art, various proposals have been made for a robot system that causes a robot to perform a screw tightening job. [Citation list][Patent literature] [PTL 1] Unexamined Japanese Patent Publication (Kokai) No. H02(1990)-237784 [PTL 2] International Unexamined Patent Publication No. 2020-518468 Summary[Technical problem]

[0005] As described above, in a robot system that causes a robot to perform screw tightening work, for example, it is necessary to perform screw tightening work on a variety of screw types, such as parameter readjustment and machining operations such as replacing a socket wrench. Therefore, there is a problem that machining requires time and effort, which particularly leads to inefficiency in the production line.

[0006] In addition, when performing the screw tightening work on a variety of screw bolt types, it is difficult to control the magnitude and direction of the force applied to each screw bolt, and it is difficult to perform the screw tightening work of a screw bolt with high accuracy.

[0007] Therefore, it is desirable to provide a robot control device, a robot system, and a robot control program that make it possible to perform a tightening work by a tightener efficiently and with high accuracy. (Solution to the problem)

[0008] According to an embodiment of the present disclosure, a robot control device for controlling a robot and causing the robot to perform a tightening work using a tightener is provided, comprising a storage unit, an acquisition unit, a setting unit, and a control unit.

[0009] The storage unit is configured to store tightener information and parameters for performing the tightening work associated with the tightener information, and the acquisition unit is configured to acquire information of the tightener performing the tightening work based on an output of a tightener detection sensor. The setting unit is configured to acquire and set the parameters associated with the tightener information from the storage unit based on the acquired tightener information, and the control unit is configured to control the robot based on the set parameters.

[0010] The objects and effects of the present invention will be realized and attained through the use of the components and combinations recited in the claims. Both the foregoing general description and the following detailed description are exemplary and descriptive, but are not limiting of the invention as recited in the claims. Brief description of the drawings

[0011] They show: [ Fig. 1] Fig. 1 is a diagram schematically showing an example of a robot in a robot system according to the present embodiment; [ Fig. 2] Fig. 2 is a block diagram showing an example of the robot system according to the present embodiment; [ Fig. 3] Fig. 3 is a diagram for describing an example of image tracking of the robot system according to the present embodiment; [ Fig. 4] Fig. 4 a diagram describing a processing in connection with a tightening operation in the Fig. 3 shown image tracking; [ Fig. 5] Fig. 5 is a diagram for describing an example of an image by a visual sensor in the example of the robot system according to the present embodiment; [ Fig. 6] Fig. 6 is a diagram for describing an example of processing by a force sensor in the example of the robot system according to the present embodiment; [ Fig. 7] Fig. 7 is a diagram for describing an example of an image displayed on a display device of the example of the robot system according to the present embodiment; [ Fig. 8] Fig. 8 is a block diagram showing another embodiment of the robot system; [ Fig. 9] Fig. 9 is a diagram for describing an example of a robot control program according to the present embodiment; [ Fig. 10] Fig. 10 is a flowchart for describing an example of the robot control program according to the present embodiment; and [ Fig. 11] Fig. 11 is a flowchart for describing processing in another example of the robot control program according to the present embodiment. Description of implementation examples

[0012] Examples of a robot control device, a robot system, and a robot control program according to the present embodiment will be described in detail below with reference to the accompanying drawings. In each of the drawings, the same or similar components are designated by the same or similar reference numerals. Furthermore, the embodiments described below do not limit the scope and meaning of the terms of the invention recited in the claims.

[0013] Fig. Fig. 1 is a diagram schematically showing an example of a robot in a robot system according to the present embodiment. In Fig. 1, reference numeral 1 denotes a robot (screw tightening robot), 3 a visual sensor (tightener detection sensor), 4 a force sensor (“force sensor”), 5 a nut driver (screw tightening device), SB a socket wrench (power socket wrench), B a screw bolt and W a workpiece (work target).

[0014] As in Fig. As shown in Figure 1, the robot 1 is formed of a multi-joint robot, and a nut driver 5 is attached to a tip (hand) of an arm 10. In this case, each joint section (shaft) of the robot 1 is provided with a force sensor 4. The force sensor 4 detects the magnitude and direction (torque) of the force at each section of the robot 1 and is configured, for example, as a torque sensor (built-in torque sensor) installed in each section.

[0015] In other words, Fig. Figure 1 shows an example in which the force sensor 4 is configured as a built-in torque sensor provided in each joint. The force sensor 4 is not limited to the built-in torque sensor in each section of the joint, but can be configured, for example, as a force sensor on the base of the robot 1. Furthermore, the force sensor 4 can detect, for example, the force of a rotation axis of the nut driver 5 (shaft for tightening the screw), i.e., the magnitude and direction of the force exerted on the screw bolt B.

[0016] Note that a visual sensor 3 for capturing an image of a workpiece W and the bolt B is mounted, for example, on a tip of the arm 10. The visual sensor 3 includes, for example, an imaging device such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), an optical lens for focusing the image onto the imaging device, an image processor, and the like, and acquires visual information.

[0017] In this case, the visual sensor 3 may be composed of a plurality of visual cameras for detecting a three-dimensional shape, a LiDAR (Light Detection and Ranging), a ToF (Time-of-Flight) camera, or a camera using a laser light section method, and the like. Depending on the tasks and specifications for which the robot system is used, a two-dimensional sensor (a visual camera) that detects a two-dimensional shape may also be used to save costs. Furthermore, the visual sensor 3 is not limited to being mounted on the tip of the arm 10, but may also be mounted above the robot 1 or on the robot 1 and configured by combining a plurality of devices arranged at various positions.

[0018] It should be noted that the visual sensor 3 is an example of a tightener detection sensor that detects information (information of the tightener B) such as the type of the bolt (tightener) B for performing a screw tightening work and a position to the workpiece W and the like, and is not limited to the visual sensor if the information (e.g., the size information) of the tightener B can be acquired. Fig. 1 shows a case where the nut driver 5 tightens the bolt B on the workpiece W, but the bolt B can be a screw, a nut, or another tightening element (tightener). Furthermore, the nut driver 5 and the socket wrench SB are only examples. Likewise, various external devices can be used to tighten the tightener.

[0019] The nut driver 5 is replaced, for example, with a socket wrench (power socket wrench) SB suitable for the type of bolt B tightened on the workpiece W, based on an output of the visual sensor 3 (command of the robot controller 2), and tightens the bolt B at a predetermined portion of the workpiece W by the socket wrench SB. Furthermore, the nut driver 5 controls, for example, the magnitude of a force for tightening the bolt B (tightening torque and the like: parameters) at the predetermined portion of the workpiece W based on an output of the force sensor 4 (command of the robot controller 2). In this case, a tip of the bolt B has already been inserted into the predetermined portion (tightening hole) of the workpiece W, but it is not possible to make various changes and modifications depending on the nut driver 5 and a screw tightening mechanism of the robot 1.

[0020] Although Fig. 1 shows a state where the bolt B is tightened from top to bottom in the vertical direction with respect to the workpiece W, the tightening direction of the bolt B with respect to the workpiece W can be any direction. Furthermore, the robot 1 is not limited to a multi-joint robot, nor is it limited to performing the bolt tightening work by the nut driver 5. In other words, other external devices for screw tightening may be adopted without using the nut driver 5, or it may be a robot that has an additional shaft (tightening motor: electric motor) for tightening the bolt B.When the robot 1 has an additional shaft for tightening the bolt B without using the nut driver 5, the force sensor 4 can be provided at any position if the magnitude and direction of the force for tightening the bolt B can be detected by the additional shaft. Furthermore, the robot 1 is not limited to tightening one bolt and one screw, but can also perform various tightening work using different tighteners. For example, in the work of inserting a pin (tightener) into a hole, instead of screwing the bolt B into the hole, an operation of selecting and inserting (tightening) an optimal pin into a hole can be performed based on information (size information) about the size of the hole detected by the vision sensor 3.

[0021] Fig. 2 is a block diagram showing an example of a robot system according to the present embodiment. As shown in Fig. 2, the robot system 100 according to the present embodiment includes a robot (screw tightening robot) 1, a robot controller 2, a tightener detection sensor 3, a force sensor 4, a nut driver 5, an operation panel (teaching operation panel) 6, and a display device 7. Note that the visual sensor is an example of a tightener detection sensor 3 that detects information (information about a tightener) such as a type of bolt B performing tightening work (screw tightening work) and a position relative to the workpiece W, and the tightener detection sensor 3 is not limited to the visual sensor.

[0022] The robot control device 2 controls the robot 1 to perform the tightening work (screw tightening work) using the tightener (screw bolt B) and includes a storage unit 21, an acquisition unit 22, a setting unit 23, and a control unit (arithmetic processing unit) 24. An output of the tightener detection sensor 3 and an output of the force sensor 4 are input to the robot control device 2, and the robot control device 2 causes the robot 1 to perform the tightening work based on information of the tightener, which will be described in detail below.

[0023] The storage unit 21 stores a robot control program for controlling the robot 1 by the control unit 24 to perform the tightening work using the tightener. In addition, the storage unit 21 stores model information of the tightener (detection models VB1, VB2, ..., a plurality of different bolt types B1, B2, ...) and parameters (parameters FB1, FB2, ... of a force control) in performing the tightening work in association with each other (corresponding to each other). In addition, the storage unit 21 stores the model information of the tightener and the information (SB1, SB2, ...) of the socket wrenches used for the tightening work in association with each other. It should be noted that the processing in an example of image tracking to which an example of the robot system according to the present embodiment is applied will be described with reference to Fig. 3 to Fig. 6 is described in detail.

[0024] The acquisition unit 22 acquires information of the tightener performing tightening work based on the output of the tightener detection sensor 3. In other words, the acquisition unit 22 receives image information acquired, for example, by the visual sensor 3, and acquires model information (detection model VB) of the bolt B performing screw tightening work, position information of the workpiece W, and the like. In this case, for example, the tightener information includes not only the bolt information indicating the type of the bolt B performing the screw tightening work, but also the position information and the like of the workpiece W of the bolt B performing the screw tightening. This is because even when one and the same bolt B is tightened, the corresponding parameters, such as the tightening torque, are different depending on the position of the workpiece W.

[0025] The setting unit 23 acquires and sets parameters corresponding to a tightener from the storage unit 21 based on the acquired information of the tightener. In other words, the setting unit 23 acquires and sets parameters associated with the acquired information (e.g., the size information) of the bolt B from the storage unit 21 based on the model information and the like of the bolt B acquired by the acquiring unit 22. In this case, the parameters stored in the storage unit 21 based on the model information and the like of the bolt B may be set, for example, to the model information of the bolt B assumed in advance before the screw tightening work is actually performed. It should be noted that the example of the processing performed in advance will be described below with reference to Fig. 9 and Fig. 10 is described in detail.

[0026] The control unit 24 controls the robot 1 based on the set parameters and causes the robot 1 to perform a tightening work of the tightener. In other words, the control unit 24 controls the robot 1 to perform a screw tightening work by using the parameters set based on the model information of the screw bolt B and the position information of the workpiece W. In this case, the control unit 24 can automatically select the socket wrench SB for tightening the screw bolt B (automatic switching) to a socket wrench corresponding to the type of the screw bolt B that performs the screw tightening work (automatic socket replacement), and the screw tightening work can be performed by the robot 1. It should be noted that the automatic selection of socket wrenches can be performed by various known methods.

[0027] As described above, the tightener detection sensor 3 is used to detect information such as the type of the tightener B that performs the screw tightening work and its position relative to the workpiece W, and it can be used with a visual sensor 3 for capturing an image including the screw bolt B and the workpiece W. Note that the visual sensor 3 may be formed of a LiDAR, a ToF camera, or a camera using an optical laser light section method as described above.

[0028] The force sensor 4 is, for example, a sensor for detecting and controlling parameters of a control device, such as a compressive force or tightening torque exerted by the nut driver 5 on the nut driver. A multi-axis force sensor with a plurality of strain gauges in each section of the robot 1, a built-in torque sensor, and a force sensor for detecting a force exerted on an additional shaft for screw tightening can be used as the force sensor 4.

[0029] For example, the operation panel 6 serves to allow a worker to move their hand and teach the robot 1 various operations, and the display device 7 serves to communicate various information to the worker through an image. The display device 7 can also be installed on the operation panel 6 or the robot control device 2 without being a separate device. Furthermore, the operation panel 6 and the display device 7 can be selected and used depending on the application target of the robot system 100, the work to be performed by the robot 1, and the like.

[0030] Fig. Figure 3 shows a diagram for describing an example of vision tracking of the example robot system according to the present embodiment. In this case, vision tracking is also referred to as conveyor tracking and performs a predetermined work on a workpiece (work target) W on a conveyor belt equipped with a sensor that detects the movement distance and speed using an output from the vision sensor (visual camera). In other words, Fig. 3 shows how several types of screw bolts B are screwed onto several workpieces W in a production line using the conveyor belt.

[0031] In Fig. 3, reference numeral 1 denotes a robot, 2 a robot control device, 3 a visual sensor, 4 a force sensor, 5 a nut driver, 8 a conveyor belt, B a screw bolt, and W a workpiece. As shown in Fig. 3, the conveyor belt 8 is moved from the lower left to the upper right in the drawing, and the robot 1 is controlled by the robot control device 2 for the plurality of workpieces W on the moving conveyor belt 8 to perform a screw tightening work of the screw bolt B. In this case, the screw bolt B is previously inserted into the tightening hole of the workpiece W at a tip of the screw bolt B, the socket wrench SB corresponding to the model (type) of each screw bolt B is exchanged, and the screw bolt B is tightened (screwed) to the predetermined portion of the workpiece W.

[0032] In other words, the robot control device 2 acquires, based on the image information acquired by the visual sensor 3, information (detection model) VB of the bolt B performing the screw tightening work, and position information and the like for the workpiece W of the bolt B. Further, based on the acquired model information of the bolt B and the position information for the workpiece W, the robot control device 2 sets corresponding parameters and causes the robot 1 (nut driver 5) to perform the screw tightening work of the bolt B based on the set parameters.

[0033] At this time, if the model of the bolt B that will perform the next screw tightening operation is different from the model of the bolt B that performed the screw tightening operation immediately before, the socket wrench SB is replaced with a bolt B corresponding to the bolt B that will perform the next screw tightening work, and then the screw tightening work is performed. When performing the screw tightening work of the bolt B, the robot controller 2 controls parameters for actually performing the screw tightening work based on the parameters corresponding to the set bolt B and an output of the force sensor 4.

[0034] Fig. 4 shows a diagram describing the processing in connection with a tightening operation in the Fig. 3 shown image tracking. Fig. 5 is a diagram for describing an example of an image by a visual sensor in an example of the robot system according to the present embodiment. Fig. 6 is a diagram for describing an example of processing by the force sensor according to an embodiment of the robot system according to the present embodiment, and shows a part of the nut driver 5 attached to the tip of the arm 10 in the robot 1.

[0035] In this case, Fig. 4(a) different types of tighteners (bolt B), and Fig. Figure 4(b) shows detection models VB (VB1, VB2, VB3, ...) corresponding to the bolts B (B1, B2, B3, ...). Fig. 4(c) Parameters FB (FB1, FB2, FB3, ...) corresponding to the bolts B (B1, B2, B3, ...), and Fig. 4(d) shows the sockets SB (SB1, SB2, SB3, ...) corresponding to the bolts B (B1, B2, B3, ...).

[0036] It should be noted that in Fig. 4(c) shows that the parameters FB represent only a force (axial force) in the axial direction and a force (tightening torque) in the rotational direction for pressing the screw B, but not only that, but other different parameters are possible. Although the parameter FB is one type for different types of screw B, for example, a variety of different parameters can be configured accordingly, which are set depending on the type, position, and the like of the workpiece W to be screwed with the same screw B. This is because even for the screw B of the same model, parameters such as the optimal tightening torque differ depending on the tightening position with respect to the workpiece W.

[0037] First, as in Fig. 1 and Fig. 2, the plurality of different types of screw bolts B1, B2, B3, ... and the parameters FB1, FB2, FB3, ... during tightening of the screw bolts B1, B2, B3, ... are associated with each other and stored in the storage unit 21. In addition, the storage unit 21 can store the types of screw bolts (model information) B1, B2, B3, ... and the types of socket wrenches SB (socket wrench information) SB1, SB2, ... associated with each other. It should be noted that the association (learning processing) of the parameters FB1, FB2, FB3, ... with respect to the plurality of screw bolts B1, B2, B3, ... of different types will be described below with reference to Fig. 9 and Fig. 10 is described in detail.

[0038] As in Fig. 5, the acquisition unit 22 extracts and acquires, for example, information about the screw bolt B (detection model VB) from an image (captured image) 300 captured by the visual sensor 3. In addition, the acquisition unit 22 compares the detection model VB extracted by the visual sensor 3 from the captured image 300 with the Fig. 4(b) and identifies (recognizes) the model of the bolt B that performs the screw tightening work.

[0039] As in Fig. 5, the image 300 captured by the visual sensor 3 includes not only a bolt B for performing the screw tightening work, but also various components attached to the workpiece W. Therefore, the acquisition unit 22 extracts the bolt B for performing the screw tightening work from the captured image 300 including the various components and the like, and acquires the information (detection model) VB of the bolt B.

[0040] The setting unit 23 reads the parameters corresponding to the detection model VB of the acquired bolt B from the storage unit 21 and sets the parameters. In this case, the parameters set by the setting unit 23 include, for example, a parameter FB of a force controller and a parameter (NB) of a nut driver 5. Note that, if it is possible to acquire the position information for the workpiece W of the bolt B on which the acquisition unit 22 performs the screw tightening work, the setting unit 23 may set the parameter FB (NB) corresponding to the detection model VB of the bolt B by adding not only the model information of the bolt B but also the position information of the workpiece W.

[0041] As in Fig. 6, the control unit 24 moves, for example, a tip of the socket wrench SB of the nut driver 5 attached to the tip of the arm 10 of the robot 1 to the position of the screw bolt B performing a screw tightening work, based on the image 300 captured by the visual sensor 3. Furthermore, the control unit 24 causes, for example, a head of the screw bolt B to be fitted into the tip of the socket wrench SB of the nut driver 5 for performing the screw tightening work, and controls the robot 1 (nut driver 5) based on the set parameter FB (NB) to perform the screw tightening work of the screw bolts B.

[0042] In other words, the control unit 24 controls the robot 1 to perform a screw tightening work with the parameter FB set by the setting unit 23 based on the model information of the screw bolt B and the position information and the like with respect to the workpiece W. In this case, the control unit 24 automatically selects the socket wrench SB for tightening the screw bolt B for the socket wrench SB corresponding to the type of the screw bolt B that performs the screw tightening work, and can perform the screw tightening work on the robot 1 as described above.

[0043] Note that the visual sensor 3 may be constituted by a LiDAR, a ToF camera, or an optical device to which a light-section method using laser light is applied, without being limited to a visual camera, if a type and the like of the bolt B performing screw tightening can be identified. Furthermore, a position of the bolt B performing the screw tightening work on the workpiece W is not limited to being calculated from an image captured by the visual sensor 3, but may be calculated, for example, by a tip position of the socket SB of the nut driver 5 obtained from a rotation angle and the like of each shaft of the robot 1.

[0044] Alternatively, but depending on the application objective, the detection model VB of the screw bolt B can also be detected by repeating the process of exchanging the socket wrench SB and fitting the screw bolt B by using the tip of the socket wrench SB as the tightening detection sensor 3.

[0045] Fig. 7 is a diagram for describing an example of an image displayed on a display device of the example of the robot system according to the present embodiment, and illustrates an example of a display image when an abnormality occurs in the screw tightening work. As shown in Fig. 2, a display device 7 can be arranged as a single device, but also on an operation panel 6 that teaches various operations on the robot control device 2 or the robot 1.

[0046] Furthermore, the display device 7 may be connected to the robot control device 2 via a communication line (e.g., LAN (Local Area Network)) without being located near the robot 1, and may also be provided in a location separate from the robot 1 (work chamber or the like). In this case, for example, an operator (worker) in the work chamber or the like provided with the display device 7 may perform various operations with reference to the display device 7. Moreover, the image displayed on the display device 7 is not limited to an image of a time point (real time) at which the screw tightening work is actually performed, but may be, for example, an image obtained by reproducing the screw tightening work from the stored data.

[0047] As in Fig. As shown in Figure 7, the display device 7 (display screen) has, for example, the display areas 7a to 7d arranged for performing various processes with respect to the operator. In this case, the display area 7a displays an image 300 captured by the visual sensor 3, e.g., the image shown in Fig. 5 above, and the display area 7b displays a work executed by the robot 1 (the robot system 100) based on a lapse of time. Furthermore, the display area 7c displays an execution history of force control of the screw tightening work (screw tightening and force execution results), and the display area 7d displays an execution history of a view of the screw tightening work (screw tightening and visual execution results).

[0048] Likewise, the display device 7 has touch-sensitive or pressure-sensitive operation buttons (operation areas) 7e to 7g. The button 7e is used, for example, to switch the display screen to a visual parameter setting screen when an abnormality occurs. Furthermore, the operation button 7f is used, for example, to switch the display screen to a force control parameter setting screen to adjust the force control parameters when an abnormality occurs. Furthermore, the operation button 7g is used to update the setting. It should be noted that the adjustment of the visual / force control parameters (including adjustment of parameters such as nut drivers and the like) can be performed automatically, but can also be performed manually by a worker in consideration of various conditions, such as items and specifications.

[0049] In this case, for example, if an alarm occurs during force control execution, visual / force parameter items related to this alarm can be automatically highlighted in the display area 7c, and the worker can specify and solve problems in a short time. Note that the alarm (warning information) can be recognized by the worker, for example, through a warning display on the screen of the display device 7 or a warning output unit such as a warning sound from the robot control device 2 and the operation panel 6, or an output of a warning lamp, and the like.

[0050] Specifically, for example, when performing a screw tightening job (2nd screw tightening function), a large torque, a short insertion depth, and a case where an alarm occurs are considered. In other words, the screw tightening job is performed without inserting the screw B at a correct angle relative to a tightening hole, and a case where an alarm (3rd alarm number 576) is generated by the force control is considered.

[0051] At this time, an image (image 300 captured by the visual sensor 3) in which an alarm is generated during the screw tightening work of the screw bolt B may be displayed in the display area 7a. Further, an angle (5th position change °) of the information (detection model: vision model) VB of the execution of the screw tightening work of the screw bolt B, which is visually detected, may be displayed together with a torque applied to the screw bolt B (8th generation force large) and an insertion depth (4th arrival depth short) when an alarm occurs.

[0052] As a result, the worker can, for example, quickly identify the cause of an alarm (occurrence of an abnormality) generated during the screw tightening work of screw bolt B. In addition, the worker can not only identify the cause of the alarm, but also adjust the visual and force control settings (visual and force parameters) so that they do not cause a similar abnormality by using the display areas 7b and 7d and the operation buttons 7e to 7g. Specifically, during the screw tightening work, the worker can intuitively perceive the diagnostic data through the force control when the abnormality occurs, so that the cause of the screw tightening failure can be quickly determined. It should be noted that the Fig. The display screen (display device 7) shown in Figure 7 is merely an example and, of course, various modifications and variations are possible.

[0053] Fig. Figure 8 shows a block diagram showing another example of the robot system according to the present embodiment. The robot system 100' of the present embodiment includes a robot 1, a robot control device 2, a visual sensor 3, a visual data processing device 30, a force sensor 4, a force data processing unit 40, a nut driver 5, an operation panel 6, and a display device 7.

[0054] In other words, as can be seen from the comparison between Fig. 8 and Fig. 2, the Fig. 8 is supplemented by the visual data processing device 30 and the force data processing unit 40. In detail, in the Fig. In the robot system 100 shown in Fig. 2, the visual data processing device 30 and the force data processing unit 40, for example, record and process various functions in the robot control device 2.

[0055] The visual data processing device 30 is provided between the visual sensor 3 and the robot control device 2 and includes a storage unit 31 and a visual data processing unit 32. The visual data processing unit 32 receives and processes an image captured by the visual sensor 3 and may, for example, include part of the functions of an acquisition unit 22 that extracts and acquires a detection model VB of the screw bolt B from the captured image. The storage unit 31 may, for example, include part of the functions of a storage unit 21 that stores the Fig. 4(b) in advance. It should be noted that the visual data processing unit 32 may, for example, include some functions of a control unit 24 that compares an extracted detection model VB with the Fig. 4(b) to identify a model of the bolt B performing a screw tightening work.

[0056] The force data processing unit 40 is located between the force sensor 4 and the robot controller 2 and includes a storage unit 41, a force data processing unit 42, and an automatic adjustment unit 43. The force data processing unit 42 receives an output of the force sensor 4 and determines a magnitude and direction of the force. Note that the force data processing unit 42 may, for example, include part of the functions of the control unit 24, which performs feedback control based on a compressive force applied to the bolt B or a tightening torque applied to the bolt B, which is obtained by processing the output of the force sensor 4.

[0057] The storage unit 41 comprises, for example, part of the functions of the storage unit 21, which stores the parameters FB1, FB2, FB3, ..., which describe the individual Fig. 4(c). Furthermore, the automatic adjustment unit 43 includes, for example, part of the functions of the control unit 24, which automatically adjusts (controls) a force applied by the robot 1 (nut driver 5) to the screw bolt B according to the parameters corresponding to the screw bolt B performing a screw tightening work.

[0058] In this case, the force data processing unit 40 can be used to prepare parameters for each of the screw bolts B1, B2, B3, ... before the screw tightening work is actually performed. It should be noted that, for example, the automatic adjustment unit 43 can apply a known technique for adjusting the parameters by automatically executing the force control a plurality of times. As described above, the robot system according to the present embodiment is not limited to the Fig. 2 and Fig. 8 models shown and can of course be changed and modified in various ways.

[0059] Fig. Fig. 9 is a diagram for describing a processing example in an example of a robot control program according to the present embodiment, and Fig. Fig. 10 is a flowchart for describing a processing example in the example of the robot control program according to the present embodiment. It should be noted that Fig. 9 and Fig. 10 are diagrams for describing an example of the processing of a pre-teaching program (screw registration program) executed before a screw tightening operation in an actual production line.

[0060] For example, the pre-learning program is stored in the storage unit 21 of the robot control device 2, and the control unit 24 performs adjustment of each item manually or automatically based on an image (detection model) VB of the screw bolt B extracted from the image captured by the visual sensor 3. Specifically, for example, when partially manually performing the teaching processing, by operating (pressing) a button VB1 of No. 1 in Fig. 9 a screen, e.g. bottom right, is displayed on a display device 7, and various items can be set.

[0061] In other words, the respective detection models VB1, VB2, ... (VB), the force control parameters FB1, FB2, ... (FB), the nut driver parameters NB1, NB2, ... (NB), and the socket wrenches SB1, SB2, ... (SB) are stored (taught) in the storage unit 21. It should be noted that the completion / non-completion of the teaching process at each item can be confirmed by a completion mark in an upper right portion of each item. For details, Fig. 9 With regard to the acquisition model VB1 and the parameter FB1, the learning process is completed (MV1, MF1), and with regard to the nut driver NB1 and the socket wrench SB1, the learning process is not completed (MN1, MS1).

[0062] In the above description, Fig. 9 is merely an example, and the items to be set in association with the detection model VB of the screw bolt B extracted from the image captured by the visual sensor 3, as well as the screens and operations displayed on the display device 7, can be modified and changed in various ways. Next, an example of processing in the example of the robot control program according to the present embodiment will be described with reference to the flowchart in Fig. 10 described.

[0063] As in Fig. 10, at the start (BEGIN) of an example of processing in the example of the robot control program (pre-teaching program) according to the present embodiment, the parameters required for screw tightening are taught in step ST11. In other words, in step ST11, the parameters required for performing screw tightening, such as a force control parameter FB and a parameter NB of a nut driver 5, are taught. Note that when an additional shaft is used for tightening a screw bolt B to a robot 1 without using the nut driver 5, the parameters (NB, FB) required for performing the screw tightening work can be taught with the external device or the additional shaft.These parameters can be learned, for example, using a well-known technique for automatic parameter adjustment by automatically executing the force control a large number of times. It is also possible to set or adjust the parameters manually.

[0064] Next, the process proceeds to step ST12, where the screw tightening parameters are set manually or automatically with respect to the screw bolt B to be machined. For example, the values ​​prepared by the manufacturer (supplier) can be automatically adjusted (set) with respect to the plurality of screw bolts (B1, B2, B3, ...) to be machined, but the operator (worker) can perform individual adjustment (fine adjustment). The automatic adjustment of the parameters (FB, NB) can be performed, for example, by the above-described automatic adjustment unit 43 (force data processing unit 40) in Fig. 8 can be made.

[0065] The process proceeds to step ST13, where the detection models VB1, VB2, VB3, ... of the bolt to be machined are taught by the visual sensor 3. In other words, in step ST13, an image (VB1, VB2, VB3, ...) of each bolt in the image captured by the visual sensor 3 is taught.

[0066] Furthermore, the process proceeds to step ST14, where the parameters, detection models, sockets, and the like are associated with each type of bolt. For example, as shown in Fig. 4, the parameters FB1, FB2, ..., the sockets SB1, SB2, ... and the detection models VB1, VB2, ... are associated with each type B1, B2, ... of screw bolts.

[0067] Further, the process proceeds to step ST15, wherein a bolt B is detected by the visual sensor 3, and the process proceeds to step ST16. In step ST16, it is determined whether or not the detected bolt B is one of the registered bolt types. If it is determined that the detected bolt B is not one of the registered bolt types (NO), then the process returns to step ST11 and the same processing can be performed. If it is determined that the detected bolt B is one of the registered bolt types (YES), the process is ended (END). It should be noted that the pre-learning program described above is merely an example and can of course be changed and modified in various ways.

[0068] Fig. Fig. 11 is a flowchart for describing a processing example in another example of the robot control program according to the present embodiment, and an example of a screw tightening operation of a screw bolt on a workpiece W in an actual production line is described. Other examples of the robot control program according to the present embodiment can be stored in the storage unit 21 of the Fig. 2 and executed by the control unit (arithmetic processing unit) 24.

[0069] As in Fig. 11, when starting (START) a processing example in another example of the robot control program (screw tightening control program) according to the present embodiment, in step ST21, a screw bolt B is detected by the visual sensor 3. Specifically, from an image including a workpiece W and the screw bolt B captured by the visual sensor 3, the screw bolt B is detected for performing a screw tightening work, and the process proceeds to step ST22.

[0070] In step ST22, it is determined whether the detected bolt B is one of the types of registered bolts, that is, it is determined whether the detected bolt B belongs to the types of bolts registered by the device with reference to Fig. 9 and Fig. 10. If, in step ST22, the detected bolt B does not correspond to the registered bolt type (NO), in other words, if the detected bolt B is a new bolt type, the process proceeds to step ST27.

[0071] In step ST27, an alarm “unregistered bolt type” is generated, and a worker performs a predetermined process based on the alarm, for example, a process after determining (NO) which is not included in the types of the bolts registered in step ST16 of Fig. 10 registered screws as described above.

[0072] On the other hand, if it is determined in step ST22 that the detected bolt B is one of the registered bolt types (YES), the process proceeds to step ST23, the screw tightening parameters are automatically set, and a socket wrench is automatically selected. In other words, the parameters corresponding to the bolt B that performs the screw tightening work can be set, and the socket wrench SB can be switched to the socket wrench SB corresponding to the bolt B that performs the screw tightening work.

[0073] The process further proceeds to step ST24, where the robot is moved to a vision correction position, and the screw tightening work of the screw bolt can be performed by force control. For example, a center position of a head portion of the screw bolt that performs the screw tightening work is calculated from an image captured by the vision sensor 3, an end portion of the socket wrench SB of the nut driver 5 is moved to the center position of the head portion of the screw bolt B that performs the screw tightening work, and the screw tightening work is performed according to the set parameters. In this case, the vision correction position in step ST24 corresponds to the center position of the head of the screw bolt B that performs the screw tightening work, which is obtained from the image captured by the vision sensor 3.

[0074] Furthermore, in step ST25, it is determined whether an abnormality occurs. If it is determined that the abnormality does not occur (NO), the screw tightening work of the screw B is terminated (END). If it is determined that the abnormality occurs (YES), the process proceeds to step ST26 to diagnose the occurrence of the abnormality. Specifically, in step ST26, a problem caused by the occurrence of the abnormality can be identified from an execution history, and the parameters can be adjusted so that the problem does not occur or no longer occurs.

[0075] As described above, with the robot control program (pre-teaching program and screw tightening control program) according to the present embodiment, the screw tightening work can be performed efficiently, and diagnosis at the time of abnormality occurrence can be easily performed. Note that, for example, the robot control program described above is executed by the control unit 24 of the robot control device 2, but it is also possible to execute the robot control program by a computer and the like added externally if the arithmetic processing capability is insufficient.

[0076] The robot control program according to the above-described embodiment may be recorded and provided in a computer-readable, non-temporary recording medium or a non-volatile semiconductor memory device, or it may be provided via wired or wireless communication. In this case, the computer-readable, non-temporary recording medium may be, for example, an optical disk such as a CD-ROM (Compact Disc Read Only Memory) or a DVD-ROM, or a hard disk device, and the like. Further, a PROM (Programmable Read Only Memory), a Flash Memory (registered trademark), and the like may be considered as non-volatile semiconductor memory devices. Furthermore, distribution from the server device may be performed via a wired or wireless WAN (Wide Area Network), LAN (Local Area Network), or the Internet.

[0077] As described in detail above, with the robot control device, the robot system and the robot control program of the present embodiment, it is possible to perform a tightening work with a tightener efficiently and with high accuracy.

[0078] Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the individual embodiments described above. These embodiments include various additions and replacements without departing from the gist of the disclosure, or without deviating from the spirit and essence of the disclosure, which are derived from the content described in the claims and their equivalents, modification, partial deletion, and the like are possible. In the embodiments described above, for example, the order of each operation and the order of each process are exemplified, but not limited thereto. The same applies when numerical values ​​or equations are used in the description of the embodiments described above.

[0079] With respect to the above-described embodiments and variations, the following description is further disclosed.

[0080] [Appendix 1] A robot control device (2) for controlling a robot (1) and causing the robot (1) to perform a tightening work using a tightener (B), comprising: a storage unit (21) configured to store information of the tightener (B) and parameters (FB, FN) for performing the tightening work associated with the information of the tightener (B); an acquisition unit (22) configured to acquire information (VB) of the tightener (B) performing the tightening work based on an output of a tightener detection sensor (3); a setting unit (23) configured to obtain and set the parameters (FB, FN) associated with the information of the puller (B) from the storage unit (21) on the basis of the acquired information of the puller (B); and a control unit (24) configured to control the robot (1) based on the set parameters (FB, FN).

[0081] [Annex 2] The robot control device as defined in Annex 1, where the control unit (24) is configured to control the robot (1) based on an output of a force sensor (4) which detects a parameter (FB) of a force control applied to the tightener (B) when performing the tightening work, and the set parameters (FB, FN).

[0082] [Annex 3] The robot control device as defined in Annex 1 or 2, where the information of the puller (B) includes model information (VB1, VB2, VB3, ...) of each puller (B1, B2, B3, ...).

[0083] [Annex 4] The robot control device according to any one of Annexes 1 to 3, wherein the information of the puller (4) includes position information of each puller (B1, B2, B3, ...) in a work target (W).

[0084] [Annex 5] The robot control device according to any one of Annexes 1 to 4, wherein the puller detection sensor (3) is a visual sensor configured to capture an image including the puller (B) and a work target (W).

[0085] [Annex 6] The robot control device according to any one of Annexes 1 to 5, wherein the robot (1) comprises an interchangeable socket wrench (SB), the storage unit (21) is configured to store the information of the tightener (B) and the information of the socket wrench (SB) used in performing the tightening work associated with the information of the tightener (B), the setting unit (23) is configured to obtain and set the information of the socket wrench (SB) associated with the information of the tightener (B) from the storage unit (21) based on the obtained information of the tightener (B); and the control unit (24) is configured to control the change of the socket wrench (SB) to be used when performing the tightening work on the basis of the set information of the socket wrench (SB).

[0086] [Annex 7] The robot control device according to any one of Annexes 1 to 6, wherein the robot (1) comprises an external device (5) or an additional shaft configured to perform the tightening work using the tightener (B), the control unit (24) is configured to control a force control parameter (FB) of the robot and parameters (NB, FB) of the external device (5) or the additional shaft based on the parameters (FB, FN) set by the setting unit (23).

[0087] [Annex 8] The robot control device as defined in Annex 7, where the external device (5) is a nut driver.

[0088] [Annex 9] The robot control device according to any one of Annexes 1 to 8, wherein the tightener (B) is a screw bolt, the tightening work using the tightener (B) is a screw tightening work of the screw bolt (B).

[0089] [Annex 10] The robot control device according to any one of Annexes 1 to 9, further comprising: a warning output unit (7, 2, 6) configured to output warning information when an abnormality occurs in the tightening work, wherein the control unit (24) is configured to identify a cause for the output of the warning information and to take an action on the warning information based on the information of the tightener (B) performing the tightening work acquired by the acquisition unit (22), the output of the force sensor (4) and the parameters (FB, FN) set by the setting unit (23) after the warning output unit (7, 2, 6) has output the warning information.

[0090] [Annex 11] A robot system (100, 100') comprising: the robot control device (2) according to any one of Annexes 1 to 10; the robot (1); the puller detection sensor; and the force sensor (4).

[0091] [Annex 12] The robot system as defined in Annex 11, which further comprises: a display device (7) configured to display information of the tightener (B) acquired by the acquisition unit (22), an output of the force sensor (4) and the parameters (FB, FN) set by the setting unit (23).

[0092] [Annex 13] The robot system as defined in Annex 12, where the display device (7) is provided on the robot control device (2) or an operating panel (6) in order to teach various operations on the robot (1).

[0093] [Annex 14] The robot system as defined in Annex 12, where the display device (7) is connected to the robot control device (2) via a communication line and is located at a location separate from the robot (1).

[0094] [Appendix 15] A robot control program for controlling a robot (1) and causing the robot (1) to perform a tightening work using a tightener (B), the robot control program causing the arithmetic processing unit (24) to execute: Learning information of the tightener (B) and parameters (FB, FN) for carrying out the tightening work associated with the information of the tightener (B); Registering the tightener (B) and the information of the tightener (B) and the parameters (FB, FN) of the execution of the tightening work associated with each type thereof; Detecting the tightener (B) performing the tightening work by a tightener detection sensor; and determining whether or not the tightener (B) performing the tightening work is a type of the registered tightener.

[0095] [Annex 16] The robot control program according to Annex 15, wherein the robot control program causes the arithmetic processing unit (24) to further execute: Adjusting the parameters (FB, FN) associated with the information of the tightener (B).

[0096] [Appendix 17] A robot control program for controlling a robot (1) and causing the robot (1) to perform a tightening work using a tightener (B), the robot control program causing the arithmetic processing unit (24) to execute: Storing information of the tightener and parameters (FB, FN) for performing the tightening work associated with the information of the tightener (B) in a storage unit (21); Obtaining the information of the tightener (B) performing the tightening work based on an output of a tightener detection sensor; Obtaining and setting the parameters (FB, FN) associated with the information of the puller (B) from the storage unit (21) on the basis of the acquired information of the puller (B); and Controlling the robot (1) based on the set parameters (FB, FN). List of reference symbols 1 robot 2 Robot control device 3 Visual sensor (attractor detection sensor) 4 force sensor 5 nut drivers (screw tightening device) 6 Control panel 7 Display device 8 Conveyor belt 10 arms 21 storage unit 22 Acquisition Unit 23 Adjustment unit 24 Control unit 30 visual data processing device 31 storage unit 32 visual data processing unit 40 Force data processing unit 41 storage unit 42 Force data processing unit 43 automatic adjustment unit 100, 100' robot system B, B1, B2, B3 screw bolts (tightener) FB, FB1, FB2, FB3 parameters (force control parameters) NB, NB1, NB2, NB3 parameters (nut driver parameters) SB, SB1, SB2, SB3 socket wrenches VB, VB1, VB2, VB3 acquisition model (applicator information) W Workpiece (work target) QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 237784

[0004] WO 2020-518468

[0004]

Claims

[1] A robot control device for controlling a robot and causing the robot to perform a tightening work using a tightener, comprising: a storage unit configured to store information of the tightener and parameters for performing the tightening work associated with the information of the tightener; an acquisition unit configured to acquire information of the tightener performing the tightening work based on an output of a tightener detection sensor; a setting unit configured to acquire and set the parameters associated with the information of the tightener from the storage unit based on the acquired information of the tightener; and a control unit configured to control the robot based on the set parameters. [2] The robot control device according to claim 1, wherein the control unit is configured to control the robot based on an output of a force sensor that detects a parameter of a force control applied to the tightener in performing the tightening work and the set parameters. [3] The robot control device according to claim 1 or 2, wherein the information of the attractor includes model information of each attractor. [4] The robot control device according to any one of claims 1 to 3, wherein the information of the attractor includes position information of each attractor in a work target. [5] The robot control device according to any one of claims 1 to 4, wherein the attractor detection sensor is a visual sensor configured to capture an image including the attractor and a work target. [6] Robot control device according to one of claims 1 to 5, wherein the robot includes an interchangeable socket wrench, the storage unit is configured to store the information of the tightener and the information of the socket wrench used in performing the tightening work, associated with the information of the tightener, the setting unit is configured to retrieve and set the socket wrench information associated with the wrench information from the storage unit based on the acquired wrench information; and the control unit is configured to control the change of the socket wrench to be used when performing the tightening work based on the set information of the socket wrench. [7] Robot control device according to one of claims 1 to 6, wherein the robot comprises an external device or an additional shaft configured to perform the tightening work using the tightener, the control unit is configured to control a force control parameter of the robot and parameters of the external device or the additional shaft based on the parameters set by the setting unit. [8] The robot control device according to claim 7, wherein the external device is a nut driver. [9] Robot control device according to one of claims 1 to 8, wherein the tightener is a screw bolt, the tightening work using the tightener is a screw tightening work of the screw bolt. [10] Robot control device according to one of claims 1 to 9, further comprising: a warning output unit configured to output warning information when an abnormality occurs in the tightening work, wherein the control unit is configured to identify a cause for the output of the warning information and to take an action on the warning information based on the information of the tightener performing the tightening work acquired by the acquisition unit, the output of the force sensor, and the parameters set by the setting unit after the warning output unit outputs the warning information. [11] Robot system comprising: the robot control device according to one of claims 1 to 10; the robot; the puller detection sensor; and the force sensor. [12] A robot system according to claim 11, further comprising: a display device configured to display the information of the tightener acquired by the acquisition unit, an output of the force sensor, and the parameters set by the setting unit. [13] A robot system according to claim 12, wherein the display device is provided on the robot control device or an operation panel to teach various operations on the robot. [14] A robot system according to claim 12, wherein the display device is connected to the control device of the robot via a communication line and is located at a location separate from the robot. [15] A robot control program for controlling a robot and causing the robot (1) to perform a tightening work using a tightener, the robot control program causing the arithmetic processing unit to execute: Learning information of the tightener and parameters for performing the tightening work associated with the information of the tightener; Registering the tightener and the tightener information and the parameters for performing the tightening work associated with each type thereof; Detecting the tightener performing the tightening work by a tightener detection sensor; and determining whether or not the tightener performing the tightening work is a type of the registered tightener. [16] The robot control program according to claim 15, wherein the robot control program causes the arithmetic processing unit to further execute: Adjust the parameters associated with the puller information. [17] A robot control program for controlling a robot and causing the robot to perform a tightening work using a tightener, the robot control program causing the arithmetic processing unit to execute: Storing tightener information and parameters for performing the tightening work associated with the tightener information in a storage unit; Obtaining the information of the tightener performing the tightening work based on the output of a tightener detection sensor; Obtaining and setting the parameters associated with the information of the attractor from the storage unit on a basis of the acquired information of the attractor; and Controlling the robot based on the set parameters.

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