Robot control device, control method, and system

Abstract

Provided are a control device, a control method, and a system having a function of preventing deterioration of machining accuracy caused by foreign matter sandwiched between a workpiece and a fixing mechanism. A control device controls a robot configured to supply a held workpiece to a fixing mechanism, the robot having a force detection unit that detects a force and a torque applied to the workpiece, the control device having a correction unit that corrects a position of the workpiece with respect to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism and corrects a position of the workpiece with respect to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism. A force control function for correcting the posture of the workpiece with respect to the fixing mechanism; when the position of the workpiece is corrected and the force detection unit detects that the torque acting in the direction in which the posture of the workpiece is corrected exceeds a first threshold value, it is determined that foreign matter is gripped between the workpiece and the fixing mechanism.

Description

Technical Field

[0001] The present disclosure relates to a control device, a control method and a system for a robot. Background Art

[0002] As a means for supplying a workpiece to a machine such as a machine tool, a robot is sometimes used. For example, a technique for supplying a workpiece to be processed to a chuck mechanism equipped on a machine tool by a robot device is known (for example, Patent Document 1).

[0003] In addition, a technology has been proposed for detecting foreign matter interposed between an object and a fixing device when the object is attached to the fixing device (for example, Patent Document 2).

[0004] Furthermore, there has been proposed a technique in which two robots respectively hold workpieces and use force control when fitting one workpiece with the other workpiece (for example, Patent Document 3).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2022 / 172873

[0008] Patent Document 2: Japanese Patent Application Publication No. 2015-104759

[0009] Patent Document 3: Japanese Patent Application Publication No. 2018-024049 Summary of the invention

[0010] Problems to be solved by the invention

[0011] When a workpiece held by a robot is supplied to a fixing mechanism such as a chuck of a machine tool, if foreign matter such as chips or fragments adheres to or gets bitten into the fixing mechanism or the workpiece, the workpiece may be fixed with the foreign matter sandwiched between the workpiece and the fixing mechanism, deteriorating the machining accuracy of the workpiece.

[0012] Means for solving problems

[0013] One embodiment of the present disclosure is a control device for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting a force and a torque applied to the workpiece, the control device having: a function of performing force control to correct a position of the workpiece relative to the fixing mechanism and then correct a posture of the workpiece relative to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism; and a function of judging that a foreign object is bitten into between the workpiece and the fixing mechanism when the force detection unit detects that the torque acting in a direction to correct the posture of the workpiece exceeds a first threshold value when the position of the workpiece is corrected.

[0014] Another embodiment of the present disclosure is a control device for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting the force and torque applied to the workpiece, the control device having: a function of performing force control to correct the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism; a function of recording the position and posture of a first workpiece when the force control is performed under normal circumstances; and a function of judging that a foreign object is bitten into the second workpiece and the fixing mechanism when the force detection unit detects that the difference between the position and posture of the second workpiece when the force control is performed and the recorded position and posture of the first workpiece exceeds a second threshold.

[0015] Another embodiment of the present disclosure is a control device for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting the force and torque applied to the workpiece, the control device having: a function of performing force control to correct the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism; a function of recording the position and posture of a first workpiece when the force control is performed under normal circumstances; a function of performing position control to correct the position and posture of a second workpiece to become the recorded position and posture of the first workpiece; and a function of judging that a foreign object is bitten into between the second workpiece and the fixing mechanism when the force detection unit detects that the force or torque acting on the second workpiece after the position control is fixed by the fixing mechanism exceeds a third threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the main parts of the robot system according to the embodiment.

[0017] Figure 2 This is a diagram showing a state where the posture of the workpiece has been corrected.

[0018] Figure 3 This is a diagram showing a state where a workpiece is fixed by a chuck.

[0019] Figure 4 is a flowchart showing the processing in the first embodiment.

[0020] Figure 5 is a flowchart showing the processing in the second embodiment.

[0021] Figure 6 is a flowchart showing the processing in the third embodiment. DETAILED DESCRIPTION

[0022] Figure 1 FIG. 1 is a schematic diagram of a main part of a robot system 10 according to a preferred embodiment. The robot system 10 includes a robot 12 and a robot control device 14 for controlling the robot 12. Figure 1 In the figure, only the movable part of the components of the robot 12, that is, the robot arm 16, and the robot hand 18 provided at the front end of the robot arm 16 are shown, and other components are omitted. The robot 12 is, for example, an industrial vertical multi-joint robot having six drive axes, but the present disclosure is not limited thereto, and a robot capable of changing position and posture by any mechanism can be used.

[0023] The robot 12 is configured to supply a workpiece 22 as a processing object to a machine tool 20. Figure 1 Only the workpiece fixing mechanism (e.g., chuck) 24 of the machine tool 20 is shown. The manipulator 18 has a gripping mechanism 26 for gripping the workpiece 22, and in the example shown in the figure, has a plurality of gripping fingers capable of gripping the roughly cylindrical workpiece 22. In addition, the manipulator 18 has a force detection unit 28 that detects force, bending moment, and deformation, etc., acting on the gripping mechanism 26 or the workpiece 22 gripped by the gripping mechanism 26. As the force detection unit 28, for example, a three-axis or six-axis force sensor that detects at least one of the external force and moment acting on the workpiece 22 can be used. However, the force detection unit is not limited thereto, and for example, a torque sensor (not shown) provided on each axis of the robot 12, or a unit (not shown) that estimates the torque based on the current value of the motor possessed by each axis of the robot 12 may be used as the force detection unit.

[0024] The machine tool 20 is configured to be able to perform predetermined mechanical processing such as cutting processing on the workpiece 22 fixed to the chuck 24. In addition, in order to remove foreign matter such as chips attached to the chuck 24 or the workpiece 22 fixed to the chuck 24, the machine tool 20 can have a cleaning device such as a nozzle 30 that sprays a fluid such as compressed gas or coolant toward the chuck 24. However, a cleaning device such as a nozzle having the same function as the nozzle 30 can also be provided on the robot 12, or other robots or peripheral equipment not shown. In either case, the cleaning device can spray the fluid according to the command output by the robot control device 14 in the processing described later to clean the chuck 24.

[0025] In the robot system 10 that supplies the workpiece 22 to the machine tool 20, as shown in FIG. Figure 1As shown in the figure, sometimes foreign matter 32 such as chips is attached to the chuck 24. If the workpiece 22 is fixed to the chuck 24 in such a state, the foreign matter 32 may bite between the workpiece 22 and the chuck 24, and the core of the workpiece 22 may be offset relative to the chuck 24, thereby reducing the processing accuracy. In addition, even if the foreign matter is not attached to the chuck 24, foreign matter such as fragments of the workpiece caused by pre-processing may be attached to the workpiece 22 held by the robot 12, and the same problem may occur in such a case. Therefore, in the following embodiment, a unit and a process for detecting the presence of such foreign matter are described.

[0026] In addition, the foreign matter in this embodiment refers to an object that can reduce the positioning accuracy of the workpiece relative to the fixing mechanism by biting into the space between the workpiece 22 and the chuck 24, and can further reduce the processing accuracy, and for example, there can be cited chips and fragments generated by the processing of the workpiece, hair of the operator, dust generated by different working environments, etc. The chips can be, for example, chips generated during the processing of the previous workpiece and attached to the chuck, and the fragments can be, for example, fragments still attached to the workpiece during pre-processing.

[0027] (First embodiment)

[0028] Figure 4 1 is a flowchart showing an example of processing in the first embodiment of the robot system 10. First, force control is performed to make the position and posture of the workpiece 22 held by the robot 12 appropriate relative to the chuck 24 of the machine tool 20. Figure 2 As shown, the workpiece 22 is first pressed against the spindle and chuck 24 of the machine tool 20 to correct the posture of the workpiece 22, and then the position of the workpiece 22 is corrected by imitating the chuck 24 when the chuck 24 is closed (steps S11 and S12).

[0029] Next, in step S12, i.e., when the position of the workpiece 22 is corrected, it is determined whether the force detection unit 28 detects a moment in the direction of correcting the posture of the workpiece 22 (hereinafter referred to as the posture correction moment). If there is no foreign matter between the workpiece 22 and the chuck 24, no posture correction moment is generated during the position correction. However, if there is a foreign matter, the posture correction moment is generated. Figure 1 Therefore, when the force detection unit 28 detects a posture correction torque greater than a predetermined threshold, it can be determined that a foreign object exists. Therefore, it is preferable to interrupt the supply operation of the workpiece 22 by the robot 12 and proceed to step S14 to remove the foreign object.

[0030] As a specific process of step S13, when the posture correction torque detected by the force detection unit 28 exceeds the prescribed first threshold value during position correction (execution of step S12), the processor of the robot control device 14 determines that a foreign object is interposed between the workpiece 22 and the chuck 24. Here, the first threshold value can be determined as, for example, the maximum value of a range that does not affect the machining accuracy of the workpiece 22, and can be determined empirically based on past performance, for example. In other words, even if a posture correction torque below the first threshold value is detected, the foreign object bitten is extremely small and is considered not to affect the machining accuracy, so it is possible to enter step S15 to continue machining the workpiece 22.

[0031] In step S14, a coolant or air is sprayed from the nozzle 30 toward the fixing mechanism (here, the chuck 24) to clean the chuck 24 (remove the foreign matter 32). This operation can be automatically performed according to the instruction from the robot control device 14. Alternatively, in addition to this, the robot control device 14 may also have a function of outputting an alarm. By outputting an alarm, an operator who recognizes this situation can manually clean the chuck 24.

[0032] In S14, if the cleaning of the chuck 24 (removal of the foreign matter 32) is completed and the posture correction torque is not detected, Figure 3 As shown, the workpiece 22 is fixed by the chuck 24. Thus, the workpiece 22 in the machine tool 20 can be processed with high precision.

[0033] (Second embodiment)

[0034] Figure 5 1 is a flowchart showing an example of processing of the second embodiment in the robot system 10. First, in a state where it can be confirmed that foreign matter is not interposed between the first workpiece and the chuck 24 (hereinafter also referred to as the normal state), force control substantially equivalent to steps S11 and S12 described in the first embodiment is performed on the first workpiece (step S21). Then, when the force control is completed (i.e., the first workpiece can be accurately positioned with respect to the chuck 24 in a correct posture), information (position data, posture data, etc.) related to the position and posture of the first workpiece is stored in an appropriate storage device (e.g., a memory of the robot control device 14) (step S22).

[0035] Next, in step S23, under conditions different from normal times (specifically, a workpiece different from normal times is supplied to a chuck 24 where the presence of foreign matter is unknown), force control substantially equivalent to steps S11 and S12 described in the first embodiment is performed on a second workpiece different from the first workpiece.

[0036] In the next step S24, the information related to the position and posture of the second workpiece when the force control of step S23 is completed is compared with the stored information of the normal state. More specifically, if the difference between the value representing the position and posture of the second workpiece in step S23 and the value representing the position and posture of the first workpiece when it is stored is within a specified second threshold value, the position and posture of the second workpiece when executing step S23 are substantially the same as those when it is normal, and the processor of the robot control device 14 can determine that there is no foreign matter between the second workpiece and the chuck 24, and therefore, the process proceeds to step S26. Figure 3 As shown, the second workpiece is fixed by the chuck 24 and the prescribed processing is performed. In addition, the second threshold value can be set as the difference in the position and posture of the workpiece as described above. As in the first embodiment, it can be determined as the maximum value of the range that does not affect the processing accuracy of the workpiece. For example, it can be determined empirically based on past performance. In other words, when the difference in position or posture between when executing S23 and when it is normal is less than the second threshold value, it is considered that even if a foreign object is bitten, it will not affect the processing accuracy. Therefore, it is possible to enter step S26 to continue processing the workpiece. In addition, the second threshold value can also be set as the ratio of the position or posture between when executing S23 and when it is normal. For example, it can be set to a value within ±5% or ±3% of the ratio of the position or posture when executing S23 to the position or posture when it is normal.

[0037] If at least one of the position and posture of the workpiece in step S23 is significantly different from at least one of the normal position and posture, it can be determined that a foreign object is between the second workpiece and the chuck 24. Therefore, it is preferred to interrupt the supply of the second workpiece by the robot 12 and proceed to step S25 to remove the foreign object. The content of step S25 can be substantially the same as step S14 of the first embodiment.

[0038] In S25, if the cleaning of the chuck 24 (removal of the foreign matter 32) is completed and the position and posture of the second workpiece during the force control are substantially the same as those during the normal operation, then Figure 3 As shown, the second workpiece is fixed by the chuck 24. Thus, the workpiece 22 in the machine tool 20 can be processed with high precision.

[0039] (Third Embodiment)

[0040] Figure 61 is a flowchart showing an example of the processing of the third embodiment in the robot system 10. First, in a state where it can be confirmed that foreign matter is not interposed between the first workpiece and the chuck 24 (hereinafter also referred to as the normal state), force control substantially equivalent to steps S11 and S12 described in the first embodiment is performed on the first workpiece (step S31). Then, when the force control is completed (i.e., the first workpiece can be accurately positioned with respect to the chuck 24 in a correct posture), information (position data, posture data, etc.) related to the position and posture of the first workpiece is stored in an appropriate storage device (e.g., a memory of the robot control device 14) (step S32).

[0041] In the next step S33, under conditions different from the normal state (specifically, the second workpiece different from the normal state is supplied to the chuck 24 where the presence of foreign matter is unknown), the position and posture of the second workpiece are controlled based on the information stored in step S32. This control is different from the force control in the first embodiment or the second embodiment, and is a position control for changing the position and posture of the second workpiece in a manner that becomes the final position and posture of the first workpiece in step S31.

[0042] In the next step S34, the operation of closing the chuck 24 is performed. At this time, it is detected whether a force or torque acts on the second workpiece or the manipulator 18. That is, if there is no foreign matter between the second workpiece and the chuck 24, no force or torque acts on the second workpiece when the chuck is fixed, but if there is a foreign matter, a force or torque above a certain level acts on the second workpiece. Therefore, if no force or torque is detected, the process proceeds to step S36. Figure 3 As shown, the operation of fixing the second workpiece with the chuck 24 is completed.

[0043] As a specific process of step S34, when the force detection unit 28 detects a force or torque greater than a specified third threshold value during the gripping action of the second workpiece by the chuck 24 after executing S33, the processor of the robot control device 14 determines that a foreign object is between the second workpiece and the chuck 24. Here, the third threshold value can be determined as the maximum value of the range that does not affect the machining accuracy of the workpiece, as in the first or second embodiment, and can be determined empirically based on past performance, for example. Conversely, when the maximum value of the force or torque detected during the period of fixing the workpiece by the chuck 24 after executing S33 is less than the third threshold value, it is considered that even if a foreign object is bitten, it will not affect the machining accuracy, and therefore, the process can proceed to step S36 to continue machining the workpiece.

[0044] When a force or torque greater than the third threshold is detected in step S34, it can be determined that a foreign object is between the workpiece 22 and the chuck 24. Therefore, it is preferred to interrupt the supply of the workpiece 22 by the robot 12 and proceed to step S35 to remove the foreign object. The content of step S35 may be substantially the same as step S14 of the first embodiment.

[0045] In S35, if the cleaning of the chuck 24 (removal of the foreign matter 32) is completed, and the position and posture of the second workpiece during the position control are substantially the same as those during the normal operation, then Figure 3 As shown, the second workpiece is fixed by the chuck 24. Thus, the workpiece 22 in the machine tool 20 can be processed with high precision.

[0046] The functions of the control device 14 described above can also be provided by a computer program executable by a processor of the control device 14. In addition, the control device 14 can have a storage device such as a memory that stores data used in each process and data generated by each process. In addition, the computer program can be recorded in a non-temporary recording medium such as a semiconductor memory, a magnetic recording medium, or an optical recording medium that can be read by a computer, such as a CD-ROM, or can be distributed from a server device on a WAN (wide area network) or a LAN (local area network) via wired or wireless communication.

[0047] According to the above-described embodiment, the presence of foreign matter between the workpiece supplied by the robot and the workpiece fixing mechanism can be detected by an easy process, thereby preventing the machining accuracy of the workpiece from being deteriorated due to the bite of the foreign matter.

[0048] The present disclosure has been described in detail, but the present disclosure is not limited to the above-mentioned embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. without departing from the scope of the main purpose of the present disclosure, or without departing from the scope of the main purpose of the present disclosure derived from the contents recorded in the scope of the patent protection requested and its equivalents. In addition, these embodiments can also be implemented in combination. For example, in the above-mentioned embodiments, the order of each action and the order of each processing are shown as an example and are not limited to this. In addition, the same is true for the case where numerical values ​​or mathematical formulas are used in the description of the above-mentioned embodiments.

[0049] The following additional remarks are disclosed in relation to the above-mentioned embodiment and modified examples.

[0050] (Note 1)

[0051] A control device for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting the force and torque applied to the workpiece, wherein the control device has: a function of performing force control to correct the position of the workpiece relative to the fixing mechanism and then correct the posture of the workpiece relative to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism; and a function of judging that a foreign object is bitten between the workpiece and the fixing mechanism when the force detection unit detects that the torque acting in the direction of correcting the posture of the workpiece exceeds a first threshold value when correcting the position of the workpiece.

[0052] (Note 2)

[0053] A control device for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting the force and torque applied to the workpiece, wherein the control device has: a function of performing force control to correct the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism; a function of recording the position and posture of a first workpiece when the force control is performed under normal circumstances; and a function of judging that a foreign object is bitten into between the second workpiece and the fixing mechanism when the force detection unit detects that the difference between the position and posture of the second workpiece when the force control is performed and the recorded position and posture of the first workpiece exceeds a second threshold.

[0054] (Note 3)

[0055] A control device for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting a force and a torque applied to the workpiece, wherein the control device has: a function of performing force control to correct the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism; a function of recording the position and posture of a first workpiece when the force control is performed under normal circumstances; a function of performing position control to correct the position and posture of a second workpiece to become the recorded position and posture of the first workpiece; and a function of judging that a foreign object is bitten between the second workpiece and the fixing mechanism when the force detection unit detects that the force or torque acting on the second workpiece exceeds a third threshold when the second workpiece after the position control is fixed by the fixing mechanism.

[0056] (Note 4)

[0057] The control device according to any one of Supplementary Notes 1 to 3, wherein:

[0058] The control device further has a function of outputting a command for cleaning the fixing mechanism when it is determined that the foreign matter is bitten.

[0059] (Note 5)

[0060] The control device according to any one of Supplementary Notes 1 to 4, wherein:

[0061] The control device further has a function of outputting an alarm when it is determined that the foreign object is bitten.

[0062] (Note 6)

[0063] A robot system, comprising: the control device according to any one of Supplementary Notes 1 to 5; and a robot controlled by the control device.

[0064] (Note 7)

[0065] The robot system according to Supplementary Note 6 comprises: a cleaning device that cleans the fixing mechanism when the bite of the foreign matter is detected.

[0066] (Note 8)

[0067] A control method for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting a force and a torque applied to the workpiece, wherein the control method includes: while the robot supplies the workpiece to the fixing mechanism, performing force control to correct the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism; and when correcting the position of the workpiece, when the force detection unit detects that the torque acting in a direction to correct the posture of the workpiece exceeds a first threshold, determining that a foreign object is bitten between the workpiece and the fixing mechanism.

[0068] (Note 9)

[0069] A control method for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting the force and torque applied to the workpiece, wherein the control method includes: performing force control to correct the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism; recording the position and posture of a first workpiece when the force control is performed normally; and determining that a foreign object is bitten into the second workpiece and the fixing mechanism when the force detection unit detects that the difference between the position and posture of the second workpiece when the force control is performed and the recorded position and posture of the first workpiece exceeds a second threshold.

[0070] (Note 10)

[0071] A control method for a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting a force and a torque applied to the workpiece, wherein the control method includes: performing force control to correct the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot supplies the workpiece to the fixing mechanism; recording the position and posture of a first workpiece when the force control is performed under normal circumstances; performing position control to correct the position and posture of a second workpiece to become the recorded position and posture of the first workpiece; and determining that a foreign object is bitten into between the second workpiece and the fixing mechanism when the force detection unit detects that the force or torque acting on the second workpiece after the position control is fixed by the fixing mechanism exceeds a third threshold.

[0072] Explanation of symbols

[0073] 10 Robotic System

[0074] 12 Robot

[0075] 14 Robot control device

[0076] 16 Robotic Arm

[0077] 18 Robot

[0078] 20 Machine Tools

[0079] 22 Workpiece

[0080] 24 Chuck

[0081] 26 Grip finger

[0082] 28 Force detection unit

[0083] 30 Nozzle

[0084] 32 Foreign matter.

Claims

1. A control device for a robot, the robot being configured to supply a held workpiece to a fixing mechanism and having a force detection unit for detecting a force and a moment applied to the workpiece, characterized in that: The control device has: A function of performing force control for correcting the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot is supplying the workpiece to the fixing mechanism; as well as When the position of the workpiece is corrected, if the force detection unit detects that the moment acting in the direction of correcting the posture of the workpiece exceeds a first threshold, a function is provided to determine that a foreign object is caught between the workpiece and the fixing mechanism.

2. A control device for a robot, the robot being configured to supply a held workpiece to a fixing mechanism and having a force detection unit for detecting a force and a torque applied to the workpiece, characterized in that: The control device has: A function of performing force control for correcting the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot is supplying the workpiece to the fixing mechanism; A function of recording the position and posture of the first workpiece when the force control is performed normally; as well as The function is to determine that a foreign object is caught between the second workpiece and the fixing mechanism when the force detection unit detects that the difference between the position and posture of the second workpiece when the force control is performed and the recorded position and posture of the first workpiece exceeds a second threshold.

3. A control device for a robot, the robot being configured to supply a held workpiece to a fixing mechanism and having a force detection unit for detecting a force and a torque applied to the workpiece, characterized in that: The control device has: A function of performing force control for correcting the position of the workpiece relative to the fixing mechanism and then correcting the posture of the workpiece relative to the fixing mechanism while the robot is supplying the workpiece to the fixing mechanism; A function of recording the position and posture of the first workpiece when the force control is performed normally; A function of performing position control to correct the position and posture of the second workpiece so as to achieve the recorded position and posture of the first workpiece; as well as The function is to determine that a foreign object is caught between the second workpiece and the fixing mechanism when the force detection unit detects that the force or torque acting on the second workpiece exceeds a third threshold when the second workpiece after the position control is fixed by the fixing mechanism.

4. The control device according to any one of claims 1 to 3, characterized in that: The control device further has a function of outputting a command for cleaning the fixing mechanism when it is determined that the foreign matter is bitten.

5. The control device according to any one of claims 1 to 4, characterized in that: The control device further has a function of outputting an alarm when it is determined that the foreign object is bitten.

6. A robot system, characterized in that: Include: A control device according to any one of claims 1 to 5; and a robot controlled by the control device.

7. The robot system according to claim 6, characterized in that: The robot system includes a cleaning device that cleans the fixing mechanism when the penetration of the foreign matter is detected.

8. A method for controlling a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting a force and a torque applied to the workpiece, wherein: The control method comprises: During the period when the robot supplies the workpiece to the fixing mechanism, force control is performed to correct the position of the workpiece relative to the fixing mechanism and then correct the posture of the workpiece relative to the fixing mechanism; as well as When the force detection unit detects that the moment acting in the direction of correcting the posture of the workpiece exceeds a first threshold value when the position of the workpiece is corrected, it is determined that a foreign object is caught between the workpiece and the fixing mechanism.

9. A method for controlling a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting a force and a torque applied to the workpiece, wherein: The control method comprises: During the period when the robot supplies the workpiece to the fixing mechanism, force control is performed to correct the position of the workpiece relative to the fixing mechanism and then correct the posture of the workpiece relative to the fixing mechanism; recording the position and posture of the first workpiece when the force control is performed normally; as well as When the force detection unit detects that the difference between the position and posture of the second workpiece when the force control is performed and the recorded position and posture of the first workpiece exceeds a second threshold, it is determined that foreign matter is caught between the second workpiece and the fixing mechanism.

10. A method for controlling a robot, wherein the robot is configured to supply a held workpiece to a fixing mechanism and has a force detection unit for detecting a force and a torque applied to the workpiece, wherein: The control method comprises: During the period when the robot supplies the workpiece to the fixing mechanism, force control is performed to correct the position of the workpiece relative to the fixing mechanism and then correct the posture of the workpiece relative to the fixing mechanism; recording the position and posture of the first workpiece when the force control is performed normally; Performing position control to correct the position and posture of the second workpiece so as to achieve the recorded position and posture of the first workpiece; as well as When the force detection unit detects that the force or torque acting on the second workpiece exceeds a third threshold value when the position-controlled second workpiece is fixed by the fixing mechanism, it is determined that foreign matter is caught between the second workpiece and the fixing mechanism.

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