Machine system for performing workpiece omission detection

Abstract

Machine system (1), comprising: a machine (11) that performs a work operation on a workpiece (10) that passes through a work area (15), an omission detection section (30) that detects that the workpiece (10) has passed through a working boundary line (16) of the machine (11) at a stage of an incomplete operation, and a reporting section (31) which, based on information from the omission detection section (30), reports information relating to the omitted workpiece (10); a first sensor (17) that detects the workpiece (10) that has passed through the working boundary line (16), wherein the omission detection section (30) detects, based on information from the first sensor (17), whether the workpiece (10) has passed through the working boundary line (16) at a stage of an incomplete operation or not; a second sensor (18) that detects the workpiece (10) arriving in the work area (15), and a workpiece management section (28) which manages at least a current position of the workpiece (10) on the basis of at least information from the second sensor (18), wherein the omission detection section (30) uses information from the workpiece management section (28) to determine whether the workpiece (10) has passed through the working boundary line (16) at a stage of an incomplete operation or not; a third sensor (19) that detects the amount of movement of the workpiece (10), and a workpiece management section (28) which manages at least a current position of the workpiece (10) on the basis of at least information from the third sensor (19), wherein the omission detection section (30) uses information from the workpiece management section (28) to determine whether the workpiece (10) has passed through the working boundary line (16) at a stage of an incomplete operation or not; characterized by the fact that the machine system (1) further comprises the following: a selection section (33) which, based on information from the second sensor (18), selects a work target from a large number of workpieces (10), wherein the omission detection section (30) detects whether the selected work target has crossed the work boundary line (16) at a stage of an incomplete operation or not, and detects whether the workpiece (10) that was not selected crosses the work boundary line (16) or not; and a prediction section (34) which, based on information from the workpiece management section (28) and a cycle time of the machine (11), predicts whether the workpiece (10) will pass through the working boundary line (16) at a stage of an incomplete operation or not, and a transport control section (35) which controls the transport of the workpiece (10) based on the prediction.

Description

[0001] The present invention relates to a machine system that performs operations on moving workpieces, and in particular to a machine system that performs omission detection of the workpiece.

[0002] When a machining operation is performed on a moving workpiece using a machine such as an industrial robot, the workpiece, because the operation is carried out within the machine's working area, may in some cases pass through the working area in an incomplete stage due to the workpiece's speed or the number of workpieces. The literature described below is known for such a machine system.

[0003] JP 2007-030087A discloses a logistical tracking device in which a robot on the upstream side determines whether each workpiece can be handled, sending data on unhandled workpieces to a robot on the downstream side, the robot on the downstream side using the received data to determine whether to handle each workpiece or not, and then sending the data on unhandled workpieces back to the robot on the downstream side.

[0004] JP 2007 - 015 055 A discloses a handling device comprising: a visual sensor that captures images of a plurality of tracking areas and detects the position of a workpiece, an encoder that detects the amount of movement of a conveyor belt, a tracking manager that identifies a tracking area during transport based on the detected amount of movement, a workpiece manager that selects an item that meets a specific condition within the identified tracking area, and a control section that controls a robot to grasp the selected workpiece.

[0005] JP 2018 - 069 377 A discloses a simulation device that simulates an article alignment operation in a virtual space, wherein a large number of articles aligned in a regular arrangement are placed on a tray.

[0006] JP 2017 - 056 529 A discloses a transport system comprising: a robot that transfers a workpiece carried by a first conveyor to a placement plate carried by a second conveyor, and a robot control system that causes the robot to perform an operation of temporarily placing the workpiece taken from the first conveyor in a temporary placement area when it is determined that workpieces have been fed to the placement plate in excess.

[0007] EP 2 998 077 A2 is the prior art of the generic type, which lacks at least the features mentioned in the characterizing part of claim 1. DE 10 2018 002 423 A1, EP 2 876 067 A1, EP 2 667 145 A1, EP 2 610 036 B1 and JP H11 - 90 871 A disclose further prior art.

[0008] Generally, workpieces skipped by a machine are often treated as defects. Since the quantity of good parts decreases when a skipped workpiece is treated as a defect, the operator can, in some cases, return the workpiece to an upstream process. However, because the operator cannot predict when a defect will occur, continuous system monitoring is necessary, increasing the operator's monitoring effort and labor costs. There is also a quality risk that the skipped workpiece could be mistakenly shipped to the end user as a non-defective item. Furthermore, it is not easy to determine how the workpiece was skipped.

[0009] Therefore, the task is to provide a technology that can detect workpiece omissions in a machine system that performs operations on moving workpieces.

[0010] According to the invention, the solution to the problem consists in a machine system with the features of claim 1, which comprises: a machine that performs an operation on a workpiece passing through a work area, an omission detection section that detects that the workpiece has passed through a working boundary line of the machine at a stage of an incomplete operation, and a reporting section that reports information relating to the omitted workpiece based on information from the omission detection section. Fig. Figure 1 is a perspective view showing the schematic configuration of a machine system according to an exemplary embodiment. Fig. Figure 2 is a block diagram of the machine system according to the exemplary embodiment. Fig. Figure 3 is a block diagram of a machine system according to another embodiment. Fig.Figure 4 is a perspective view showing a modified example of a machine system. Fig. Figure 5 is a flowchart showing the schematic operation of the machine system.

[0011] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. In the drawings, identical or similar constitutive elements are designated with the same or similar reference numerals. Furthermore, the embodiments described below do not limit the technical scope of the invention or the definitions of the terms described in the claims.

[0012] Fig.Figure 1 shows the schematic configuration of a machine system 1 according to the present embodiment. The machine system 1 comprises one or more machines 11 that perform a predetermined operation on a workpiece 10, a tool 12 mounted at the top of the machine 11, and a controller 13 that controls the machine 11 and the tool 12. The workpiece 10 comprises an article 10a or a tray 10b onto which the article 10a can be placed, and is transported by a transport section 14, such as a conveyor or an automated guided vehicle (AGV), so that it reaches a working area 15 of the machine 11. The machine 11 is a parallel joining robot, but could also be another industrial robot, such as an articulated robot, or another industrial machine, such as a machine tool or construction machine. The tool 12 is a suction hand, which, for example,The tool 12 is used to position four items 10a on a tray 10b. However, the tool 12 can be a hand with several fingers or another tool, e.g., a sealing tool, a welding tool, a screw tool, a soldering tool, or a laser processing tool, depending on the content of the operation on the workpiece 10. The controller 13 can be a known controller that includes a processor such as a CPU (central processing unit).

[0013] Since machine 11 performs an operation on a moving workpiece 10, it can happen in some cases that the workpiece passes through the working area 15 in an incomplete operation due to the workpiece's speed or the number of workpieces. Therefore, the machine system 1 includes a working boundary line 16 for each machine 11, or a working boundary line 16 only for the machine 11 located furthest downstream among the multiple machines 11, and is configured to perform a workpiece omission detection when the workpiece 10 passes through the working boundary line 16 in an incomplete operation.Although the working boundary line 16 is provided on the downstream side within the working area 15 in the direction of movement X of the workpiece, it may be provided further downstream than the working area 15 of the most downstream machine 11 (see the reference numeral 16 on the far right in . Fig. 1).

[0014] To perform omission detection of workpiece 10, machine system 1 can include a first sensor 17 for monitoring the working boundary line 16. The first sensor 17 can be a two-dimensional or three-dimensional camera capable of detecting workpiece 10. Machine system 1 can detect whether workpiece 10 has crossed the working boundary line 16 or not, or it can use the first sensor 17 to detect whether the operation on workpiece 10 is complete or not. As a result of the first sensor 17, it is possible, for example, to detect whether article 10a is placed at a predetermined position on tray 10b or not, or whether sealing, spot welding, etc., is completed at a predetermined location on article 10a, etc.

[0015] Alternatively, the machine system 1 can include a second sensor 18 for detecting the arrival of the workpiece 10. The second sensor 18 can be a two-dimensional camera, a three-dimensional camera, etc., capable of detecting the position, orientation, amount of movement, etc., of the workpiece 10, or it can be a photoelectric sensor, a contact sensor, etc., capable of detecting only the position of the workpiece 10. If the latter sensor is used, the machine system 1 can include, in addition to the second sensor 18, a third sensor 19 capable of detecting the amount of movement of the workpiece 10. The third sensor 19 can be a rotary encoder or similar device attached to a rotary shaft of the transport section 14.The machine system 1 manages at least the current position of the workpiece 10 as needed based on the information from the second sensor 18 and the information from the third sensor 19, and can, without using the first sensor 17, recognize based on the current position of the workpiece 10 whether the workpiece 10 has passed through the working boundary line 16 at a stage of an incomplete operation or not, or can recognize whether the operation on the workpiece 10 is completed or not.

[0016] Alternatively, if the reference position of the workpiece 10 is known, the machine system 1 manages the current position of the workpiece 10 based on the amount of movement of the workpiece 10 detected by the third sensor 19, without using the first sensor 17 or the second sensor 18, and can, based at least on the current position of the workpiece 10, determine whether the workpiece 10 has passed through a transport deceleration line 16b at a stage of an incomplete operation or not, or can determine whether the operation on the workpiece 10, which lies between the work boundary line 16a and a transport acceleration line 16c, is completed or not.

[0017] Based on the omission detection of workpiece 10, machine system 1 reports information regarding the omitted workpiece 10 to an operator or other device. This omission notification allows the operator or other device to take any desired action on the workpiece at a specific time. Furthermore, machine system 1 may include a work step compensation section 20 for compensating the work step based on the workpiece omission notification.The work step compensation section 20 is provided on the downstream side of the work boundary line 16 and includes a dispenser that dispenses the omitted item 10a or the omitted tray 10b, a refiller that replenishes the tray 10b if an item 10a is missing, or a transport machine that returns the omitted item 10a or the omitted tray 10b to the upstream area in front of the work area 15.

[0018] Fig.Figure 2 shows the configuration of machine system 1. The control unit 13 comprises a memory section 22, which stores at least one work program 21; a work operation control section 23, which controls the operation of machine 11 based on the work program 21; a machine drive section 25, which drives a machine drive motor 24; and a tool drive section 27, which drives a tool drive motor 26. The work program 21 is a program in which basic work commands of machine 11 are described in accordance with the work content, and the work operation control section 23 issues work commands to the machine drive section 25 or the tool drive section 27 based on the work program 21. The machine drive section 25 or the tool drive section 27 supplies power to the machine drive motor 24 or the tool drive motor 26 based on the work commands.

[0019] The control unit 13 further comprises a workpiece management section 28, which manages information (current position, orientation, amount of movement, operation stage, etc.) of the workpiece, and a converter 29, which converts the information (current position, orientation, amount of movement, etc.) of the workpiece from a sensor coordinate system into a machine coordinate system. The workpiece management section 28 can manage at least the current position of the workpiece by using only the second sensor 18, the second sensor 18 and the third sensor 19, or only the third sensor 19 if the reference position of the workpiece is known in advance. If the machine system 1 comprises a plurality of machines 11, the workpiece management section 28 can further manage the work distribution of the workpiece among the plurality of machines 11. The workpiece management section 28 can manage the workpiece information using a workpiece database, such as...The following table shows that the workpiece database is synchronized or shared among a variety of controllers (13). [Table 1] Article No. Current position Division of labor work stage 1 X420, Y12 Machine No. 1 Completed 2 X381, Y15 Machine No. 1 Unfinished 3 X286, Y13 Machine No. 1 Unfinished 4 X180, Y14 Machine No. 1 Unfinished Tray No. Current Position Position 1 2nd place 3rd place 4th place work stage 1 X410,Y14 Now n / a n / a n / a UNFINISHED 2 X381,Y15 n / a n / a n / a n / a UNFINISHED workpiece movement amount 20 cm / s machine Nr. Work area Ar boundary line 1 X2 00-X300 X 300 2 X4 00-X500 X 500

[0020] When a workpiece arrives within the work area, the workpiece management section 28 continuously transmits the workpiece information (current position, orientation, amount of movement, etc.) to the converter 29, and the converter 29 continuously converts the workpiece information (current position, orientation, amount of movement, etc.) from the sensor coordinate system to the machine coordinate system. The operation control section 23 continuously transmits work commands to the machine drive section 25, including a target operation (target position, target speed, target orientation, etc.) for the machine, in accordance with the workpiece information (current position, orientation, amount of movement, etc.) sent to the machine drive section 25. As a result, the machine 11 can perform the operation while tracking the workpiece.When the operation on the specific workpiece is completed, the workpiece management section 28 continuously transmits the information (current position, orientation, amount of movement, etc.) of a subsequent workpiece to the converter 29, and the operation described above is repeated. If the workpiece management section 28 manages the workpiece information (current position, orientation, amount of movement, etc.) in the machine coordinate system, the converter 29 can be positioned between each sensor and the workpiece management section 28.

[0021] The control unit 13 further comprises an omission detection section 30 for detecting when workpieces are omitted, and a reporting section 31 that reports information relating to the omitted workpiece based on the information from the omission detection section 30. The omission detection section 30 detects whether the workpiece has crossed the working boundary line at a stage of an incomplete operation, using only the first sensor 17 or the information from the workpiece management section 28. If the first sensor 17 is used, the omission detection section 30 can perform these determinations by identifying the workpiece, for example, by applying pattern matching or ink blot detection to the information from the first sensor 17.

[0022] When the information from workpiece management section 28 is used, omission detection section 30 can detect an omission of item no. 1 by, for example, referring to the workpiece database described above and comparing the current position (X420) of item no. 1 with the position (X300) of the working boundary line of machine no. 1. Furthermore, omission detection section 30 can detect an omission of tray no. 1 by, for example, referring to the workpiece database described above, comparing the current position (X410) of tray no. 1 with the position (X300) of the working boundary line of machine no. 1 and determining the presence or absence of items at placement positions 1 to 4 of tray no. 1.

[0023] The omission detection section 30 performs the same omission detection in embodiments where another operation, such as sealing or welding, is carried out. The omission detection section 30 can determine from the operation stage whether the operation is complete at the sealing or welding point of the workpiece or not, for example by referring to the workpiece database described above and comparing the current position of the workpiece with the position of the working boundary line.

[0024] Reporting section 31 provides the operator or other equipment with information regarding the skipped workpiece. Examples of skipped workpiece information include the fact that the workpiece was skipped, the number of skipped workpieces, and the incomplete machining portion of the workpiece. The skipped workpiece notification, or the number of skipped workpieces, enables the operator or other equipment to perform any type of process on the skipped workpiece at the desired time. Furthermore, the incomplete machining portion notification allows the operation to be performed only on that incomplete machining portion.As a result of this notification of a workpiece omission, the monitoring effort for the operator can be reduced, thereby improving the quantity of good parts and reducing the risk of quality degradation.

[0025] The reporting section 31 transmits information regarding the omitted workpiece to another device, such as the work compensation section 20, the workpiece management section 28, etc. Based on the report of a workpiece omission, the work compensation section 20 performs work compensation, such as dispensing the omitted item and tray, replenishing the tray with the missing item, or returning the omitted item or tray upstream of the work area. Additionally, if each machine is equipped with a work boundary line, the workpiece management section 28 can distribute a omitted workpiece to a downstream machine 11 based on the report of a workpiece omission.

[0026] The control unit 31 can further include a selection section 33, which selects a work target from the multitude of workpieces based on information from the second sensor. Selection section 33 can select non-defective / defective items based, for example, on the presence or absence of scratches, or it can select whether a work operation has been performed based on the presence or absence of a label. In this case, the omission detection section 30 can detect whether the selected work target has crossed the work boundary line at a stage of an incomplete work operation, or it can simply detect whether a non-selected workpiece (e.g., a defective item, etc.) has crossed the work boundary line.

[0027] The control unit 13 can include a prediction section 34, which, based on information from the workpiece management section 28 and the cycle time of the machine 11, predicts whether the workpiece will cross the working boundary line at a stage of an incomplete operation, and a transport control section 35, which controls the transport of the workpiece based on the prediction results. The prediction section 34 predicts whether item no. 2 will cross the working boundary line at a stage of an incomplete operation by, for example, referring to the workpiece database described above, calculating the arrival time (t2 = d2 / v) at which item no. 2 reaches the working boundary line based on the amount of movement (v = 20 cm / s) of the workpiece and the distance (d2 = X500 - X380) of item no. 2 to the working boundary line, and comparing the arrival time (t1) with the cycle time (c) (t2 - c > 0).Furthermore, the prediction section 34 performs the same prediction for the next arriving item No. 3 (t3 - 2c > 0). If it is predicted that item No. 3 will cross the work boundary line in an incomplete operation stage (t3 - 2c ≤ 0), the transport control section 35 drives a transport drive motor 36 at the transport speed (v' < d3 / 2c) so that item No. 3 does not cross the work boundary line in an incomplete operation stage.

[0028] Fig.Figure 3 shows the configuration of a machine system 1 according to another embodiment. In this configuration, the machine system 1 comprises a host computer device 32, and the host computer device 32 is communicatively connected to each controller 13. The host computer device 32 is configured to process the information from each sensor, such as the first sensor 17, the second sensor 18, and the third sensor 19, at high speed and, based on the processing results, issues various commands to each controller 13. The workpiece management section 28, the converter 29, the omission detection section 30, the signaling section 31, the selection section 33, the prediction section 34, and the transport control section 35 are not provided individually in each controller but are integrated into the host computer device 32.This allows different programs and different data from the multiple controllers 13 to be used together, thereby increasing the maintainability of the machine system 1.

[0029] Fig. Figure 4 shows a modified example of machine system 1. In this modified example, the work compensation section 20 includes a circulating conveyor 37. The circulating conveyor 37 distributes the workpiece 10 when there is no signal indicating that a workpiece 10 has been skipped, and returns the skipped workpiece 10 upstream of the work area 15 when there is a signal indicating that a workpiece 10 has been skipped. This allows the machine 11 to resume the operation on the skipped workpiece 10.

[0030] Fig.Figure 5 shows the schematic operation of machine system 1. In step S10, the second sensor detects at least the position of the workpiece, and in step S11, the third sensor detects the amount of movement of the workpiece. However, if the second sensor can also detect the amount of movement of the workpiece, because the current position of the workpiece can be managed solely with the second sensor, then the process of step S11 is unnecessary. Furthermore, if the reference position of the workpiece is known in advance, the process of step S10 is unnecessary, since the current position of the workpiece can be managed only with the third sensor.

[0031] In step S12, at least the current position of the workpiece is managed. If multiple machines are used, the workload distribution of the workpieces across these machines can be managed. In step S13, at least the current position of the workpiece is converted from the sensor coordinate system to the machine coordinate system. However, if the workpiece information (current position, orientation, amount of movement, etc.) is managed in the machine coordinate system, the process of step S13 can be performed between steps S11 and S12.

[0032] In step S14, the machine tracks the workpiece based on information about it (current position, orientation, amount of movement, etc.). In step S15, the machining operation is performed on the workpiece using the tool. In step S16, it is determined whether the workpiece has crossed the working boundary line in an incomplete machining operation. If the workpiece has crossed the working boundary line in an incomplete machining operation (YES in step S16), a message about the workpiece being passed is issued to the operator or another device in step S17, and work compensation is performed. If the workpiece has not crossed the working boundary line in an incomplete machining operation (NO in step S16), no message about the workpiece being passed is issued.

[0033] According to the above embodiments, since a skipped workpiece 10 is detected by the machine 11 and information relating to the skipped workpiece is reported, the operator or another device can perform a type of process on the workpiece 10 at a predetermined time. As a result of the report about the skipped workpiece, the monitoring effort for the operator can be reduced, thereby improving the quantity produced and reducing the risk of quality degradation.

[0034] The "sections" described above can consist of integrated semiconductor circuits or of programs executed by a processor. Furthermore, the program for executing the flowchart described above can be stored and made available on a computer-readable, non-volatile data carrier, such as a CD-ROM.

Claims

[1] Machine system (1), comprising: a machine (11) that performs a work operation on a workpiece (10) that passes through a work area (15), an omission detection section (30) that detects that the workpiece (10) has passed through a working boundary line (16) of the machine (11) at a stage of an incomplete operation, and a reporting section (31) which, based on information from the omission detection section (30), reports information relating to the omitted workpiece (10); a first sensor (17) that detects the workpiece (10) that has passed through the working boundary line (16), wherein the omission detection section (30) detects, based on information from the first sensor (17), whether the workpiece (10) has passed through the working boundary line (16) at a stage of an incomplete operation or not; a second sensor (18) that detects the workpiece (10) arriving in the work area (15), and a workpiece management section (28) which manages at least a current position of the workpiece (10) on the basis of at least information from the second sensor (18), wherein the omission detection section (30) uses information from the workpiece management section (28) to determine whether the workpiece (10) has passed through the working boundary line (16) at a stage of an incomplete operation or not; a third sensor (19) that detects the amount of movement of the workpiece (10), and a workpiece management section (28) which manages at least a current position of the workpiece (10) on the basis of at least information from the third sensor (19), wherein the omission detection section (30) uses information from the workpiece management section (28) to determine whether the workpiece (10) has passed through the working boundary line (16) at a stage of an incomplete operation or not; characterized by , that the machine system (1) further comprises the following: a selection section (33) which, based on information from the second sensor (18), selects a work target from a large number of workpieces (10), wherein the omission detection section (30) detects whether the selected work target has crossed the work boundary line (16) at a stage of an incomplete operation or not, and detects whether the workpiece (10) that was not selected crosses the work boundary line (16) or not; and a prediction section (34) which, based on information from the workpiece management section (28) and a cycle time of the machine (11), predicts whether the workpiece (10) will pass through the working boundary line (16) at a stage of an incomplete operation or not, and a transport control section (35) which controls the transport of the workpiece (10) based on the prediction. [2] Machine system (1) according to claim 1, comprising: a multitude of the machines (11), wherein the workpiece management section (28) further manages the work distribution of the workpiece (10) to the multitude of machines (11). [3] Machine system (1) according to claim 1 or 2, comprising: a plurality of machines (11), each of the machines (11) being provided with the working boundary line (16), and when the workpiece (10) has passed through the working boundary line (16) at a stage of an incomplete operation, the workpiece management section (28) distributes the skipped workpiece (10) to a downstream machine (11). [4] Machine system (1) according to any one of claims 1 to 3, comprising: a plurality of machines (11), wherein only the machine (11) which is located furthest downstream from the majority of the machines (11) is provided with the working boundary line (16). [5] Machine system (1) according to one of claims 1 to 4, wherein the working boundary line (16) is provided downstream within the working area (15) in a direction of movement of the workpiece (10). [6] Machine system (1) according to any one of claims 1 to 5, wherein information relating to the skipped workpiece (10) includes at least one of the fact that the workpiece (10) has been skipped, the number of skipped workpieces (10), and an incomplete machining part of the workpiece (10). [7] Machine system (1) according to any one of claims 1 to 6, further comprising: a work compensation section (20) that compensates for the operation based on the notification. [8] Machine system (1) according to claim 7, wherein the work compensation section (20) comprises a dispenser that dispenses the missing workpiece (10), a refiller that refills the workpiece (10), or a transport machine that returns the omitted workpiece (10) upstream of the working area (15). [9] Machine system (1) according to claim 7 or 8, wherein the work compensation section (20) comprises a circulating conveyor which returns the skipped workpiece (10) upstream of the working area (15). [10] Machine system (1) according to any one of claims 1 to 9, wherein the machine (11) performs the operation while tracking the workpiece (10) on the basis of a current position of the workpiece (10). [11] Machine system (1) according to any one of claims 1 to 10, wherein the workpiece (10) comprises an article or a tray on which the article can be placed. [12] Machine system (1) according to any one of claims 1 to 11, wherein the machine (11) comprises a robot or an industrial machine.

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