Robot control device and robot control method

Abstract

To correct deviation of a posture at which a robot supplies a workpiece, while continuing the production.SOLUTION: A robot control device for controlling a robot performing attachment and removal of a workpiece relative to a processing machine includes: a correction part for correcting a posture of a robot on the basis of a measurement value of a sensor that measures a load of the robot; a robot posture acquisition part; a storage part for saving a posture of the robot; a workpiece attachment target posture generation part; and a path generation part for generating an operation of the robot in accordance with the workpiece attachment target posture. The correction part corrects a posture of the robot so that a load of the robot is smaller than a preset threshold value, when the robot is performing the workpiece after processing. The robot posture acquisition part acquires a removal posture that is a posture of the robot after correction and saves the corrected posture in the storage part, for performing a plurality of workpieces after processing. The workpiece attachment target posture generation part generates a new workpiece attachment target posture on the basis of the plurality of removal postures saved in the storage part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control technology for a robot, and more particularly to a control technology for a robot that supplies a workpiece to an automatic machine tool. [Background technology]

[0002] When a robot attaches a workpiece to a processing machine, if there is a deviation in the posture of the robot supplying the workpiece, an excessive load may be applied to the robot when the processing machine grasps the workpiece. For example, JP 2012-176477 A (Patent Document 1) discloses a technology for adjusting the posture of the robot supplying the workpiece.

[0003] Patent Document 1 states, "(A) trajectory data is generated from a CAD model of the workpiece and stored in a storage device, (B) before machining, the workpiece is traced along the trajectory data at a tracing speed slower than the machining speed without machining the workpiece, and the trajectory data is corrected from the operating position to set a target trajectory, (C) next, based on the target trajectory, the position of the machining tool is controlled at the machining speed without contacting the workpiece, and learning to re-correct the trajectory data is repeated and stored as target trajectory data to be used in machining, and (D) during machining, the position of the machining tool is controlled at the machining speed based on the learned trajectory data to machine the workpiece." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-176477 A Summary of the Invention [Problem to be solved by the invention]

[0005] A conventional method for adjusting the posture of a robot when it supplies workpieces involves simultaneously holding a master workpiece without dimensional error by the holding device (chuck) of the machining machine and by the robot, adjusting the robot posture so that no load is placed on the robot, and registering that posture.

[0006] For example, Patent Document 1 describes a technology in which, when a workpiece held by a holding device is machined by a machining tool attached to the tip of a robot arm, the trajectory data of the robot is learned using the workpiece before machining, and the machining tool is controlled based on the learned trajectory data to machine the workpiece. Similarly, the robot grasps the workpiece before machining and moves it to a holding position by the chuck of the processing machine, learns a posture that places no load on the robot when the chuck holds the workpiece, and supplies the subsequent workpiece in the learned posture, thereby preventing excessive load from being placed on the robot.

[0007] However, in reality, there are cases where the dimensions of the workpiece before machining change due to, for example, changes in the manufacturing process of the workpiece to be machined, or the workpiece has a large dimensional error such as a casting, or the dimensions of the hand of the robot that supplies the workpiece change due to replacement or modification of the hand, and there is a problem that operating efficiency decreases when production is stopped each time and a master work is used for learning.

[0008] An object of the present invention is to provide a method for correcting deviations in the supply posture of a workpiece by a robot while continuing production using the workpiece to be machined. [Means for solving the problem]

[0009] In order to solve the above problems, the configurations described in the claims are adopted, for example. The present application includes a plurality of means for solving the above problems, and examples thereof are given below. That is, a robot control device that controls a robot that loads and removes a workpiece on a processing machine includes a correction unit that corrects the posture of the robot based on measurement values ​​of a sensor that measures the load of the robot, a robot posture acquisition unit that acquires the posture of the robot, a memory unit that stores the posture of the robot acquired by the robot posture acquisition unit, a work mounting target posture generation unit that generates a work mounting target posture which is a target posture for mounting the workpiece on the processing machine, and a path generation unit that generates an operation of the robot according to the work mounting target posture, wherein the correction unit corrects the posture of the robot so that the load on the robot is reduced when the robot grasps the workpiece after processing by the processing machine, the robot posture acquisition unit acquires removal postures which are the corrected postures of the robot for a plurality of the workpieces after processing and stores them in the memory unit, and the work mounting target posture generation unit generates a new work mounting target posture based on the plurality of removal postures stored in the memory unit. Effect of the Invention

[0010] According to one aspect of the present invention, it is possible to correct a deviation in the posture of a workpiece being fed by a robot while continuing production, using the workpiece to be machined. Problems, configurations, and effects other than those described above will become apparent from the description of the following embodiments. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing an example of the configuration of a work supply system using a robot according to an embodiment of the present invention. FIG. [Diagram 2] 1 is a block diagram showing an example of a configuration of a robot control device according to an embodiment of the present invention. [Figure 3A] 4 is a flowchart illustrating an example of a process executed by a robot control device according to an embodiment of the present invention. [Figure 3B]4 is a flowchart illustrating an example of a process executed by a robot control device according to an embodiment of the present invention. [Figure 4] FIG. 2 is an explanatory diagram showing a first example of machining to which the workpiece supply system according to the embodiment of the present invention is applied; [Diagram 5] FIG. 11 is an explanatory diagram showing a second example of machining to which the workpiece supply system according to the embodiment of the present invention is applied. [Figure 6] FIG. 11 is an explanatory diagram showing an example of workpiece supply target posture update executed by the robot control device according to the embodiment of the present invention. [Figure 7] FIG. 2 is an explanatory diagram showing an example of a work abnormality determination executed by a robot control device according to an embodiment of the present invention. [Figure 8] 4A to 4C are explanatory diagrams showing examples of attachment attitude information, removal attitude information, workpiece supply target attitude information, and workpiece dimension error information held by a robot control device according to an embodiment of the present invention. [Figure 9] FIG. 4 is an explanatory diagram illustrating an example of threshold value information held by a robot control device according to an embodiment of the present invention. [Figure 10] FIG. 2 is an explanatory diagram showing a first example of information output by the robot control device according to the embodiment of the present invention. [Figure 11] FIG. 11 is an explanatory diagram showing a second example of information output by the robot control device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. For convenience, when necessary, the description will be divided into a plurality of sections or examples, but unless otherwise specified, they are not unrelated to each other, and one is related to the other as a partial or complete modification, details, supplementary explanation, etc. In addition, in the following, when the number of elements (including the number, numerical value, amount, range, etc.) is mentioned, it is not limited to the specific number, except when otherwise specified or when it is clearly limited to a specific number in principle.

[0013] FIG. 1 is a block diagram showing an example of the configuration of a workpiece supply system 100 using a robot according to an embodiment of the present invention.

[0014] The work supply system 100 is composed of a work supply device 10, a robot control device 14, and a work instruction device 12. The work supply device 10 is composed of a robot arm 1, a hand 2, and a force sensor 3. The hand 2 is attached to the tip of the robot arm 1, and operates according to operation commands from the robot control device 14.

[0015] The work supply device 10 moves an object to be processed (work) 4 from its storage position to a holding position held by a holding device (chuck) 5 of the processing machine, and moves the processed work 4 from the holding position held by the chuck 5 to the storage position. The work instruction device 12 instructs from where to where to move the work 4, that is, the starting position and the destination position. The robot control device 14 generates a movement path from the starting position to the destination position of the work 4, and controls the attitude of the robot arm 1 and the hand 2 so that the work 4 moves on the movement path. The robot control device 14 also acquires the measurement value of the force sensor 3 and the position, attitude, or joint angle of the robot arm 1, and corrects the attitude of the robot arm 1 and the hand 2 by feeding back the values.

[0016] 1 shows a chuck 5 of the processing machine, but does not show the main body of the processing machine. The processing machine is, for example, a lathe processing machine or an end mill processing machine, but may be another type.

[0017] Although the robot arm 1 is illustrated as being fixed to the floor, it may be attached to a moving body (not shown) such as a cart or an automatic guided vehicle. In this embodiment, an example is described in which the robot arm 1 is operated with the cart or automatic guided vehicle installed in front of a processing machine, but the robot arm 1 may be operated while the cart or automatic guided vehicle is moving. When the robot arm 1 is operated while the cart or automatic guided vehicle is moving, the position information of the cart or automatic guided vehicle is taken into the robot control device 14. The movement mechanism and control method of the cart or automatic guided vehicle, and the method of acquiring the position information may be general methods.

[0018] The force sensor 3 may be of any type as long as it outputs a signal indicating the magnitude of an external force acting on the hand 2. For example, the force sensor 3 may be a pressure sensor, an image sensor, a strain gauge, or the like.

[0019] FIG. 2 is a block diagram showing an example of the configuration of the robot control device 14 in the embodiment of the present invention.

[0020] The robot control device 14 is composed of a calculation unit 21, a storage unit 22, an input unit 24, a display unit 25, and a communication unit 26. The calculation unit 21 includes a force feedback correction unit 211, a robot attitude acquisition unit 212, a workpiece supply target attitude information update unit 213, a workpiece dimension error calculation unit 214, an abnormality determination unit 216, a path generation unit 218, and a control unit 219. The processes executed by these units will be described later.

[0021] The storage unit 22 holds attachment attitude information 221, removal attitude information 222, workpiece supply target attitude information 223, workpiece dimension error information 224, threshold information 225, environment information 226, and robot information 227. Details of these pieces of information will be described later.

[0022] The input unit 24 is an input unit for inputting various information, inputting menu selection instructions, and inputting other instructions, and is, for example, a keyboard, a mouse, a touch panel, a card reader, a microphone, etc. Alternatively, the robot control device 14 may be configured to accept input of information between other devices via the communication unit 26. The information input by the input unit 24 is stored in the storage unit 22. The display unit 25 is a display unit for displaying input information, displaying processing results, and displaying the progress of processing, and is, for example, a screen display device such as a liquid crystal monitor, an LCD (Liquid Crystal Display), or a graphic card, a printer, or a sound output device such as a speaker. Alternatively, the robot control device 14 may be configured to output information between other devices via the communication unit 26. The communication unit 26 is a communication unit for transmitting and receiving data between other devices such as the work supply device 10 and the work instruction device 12. Some of the components shown in FIG. 2 may be omitted, and other components may be added. The robot control device 14 may be configured such that all or part of the configuration is realized by virtual resources such as a cloud server.

[0023] Next, the procedure of the process executed by the robot control device 14 will be described.

[0024] 3A and 3B are flowcharts showing an example of processing executed by the robot control device 14 in the embodiment of the present invention.

[0025] First, the control unit 219 reads the workpiece supply target attitude information 223 (step 301). The workpiece supply target attitude information 223 includes information indicating a target attitude when each workpiece 4 is supplied to the chuck 5. In this embodiment, the workpiece supply target attitude is described as an example consisting of the coordinate values ​​of each of the X, Y, and Z axes that are targets of the movement of the hand 2 gripping the workpiece 4, and the roll angle, pitch angle, and yaw angle that indicate the attitude of the hand 2 at the position indicated by the coordinate values ​​(details will be described later with reference to FIG. 8), but it may be composed of the joint angle of the robot arm 1. In this embodiment, the attitude of the hand 2 gripping the workpiece 4 is specified by the coordinate values ​​of each of the X, Y, and Z axes, and the roll angle, pitch angle, yaw angle, or joint angle. The control unit 219 acquires the workpiece supply target attitude regarding the workpiece 4 to be machined from the workpiece supply target attitude information 223.

[0026] Next, the path generating unit 218 generates a path for moving the workpiece 4 to be processed from the standby position to the workpiece supply target posture (step 302). This path generation can be performed in the same manner as in the past, and therefore a detailed description will be omitted.

[0027] Next, the control unit 219 controls the robot arm 1 so that the hand 2 moves to a standby position for the workpiece 4 to be processed, and controls the hand 2 so that the hand 2 grips the workpiece 4 to be processed (step 303). Then, the control unit 219 controls the robot arm 1 to move the hand 2 gripping the workpiece 4 to the workpiece supply target posture via the path generated in step 302 (step 304).

[0028] When the hand 2 moves to the workpiece supply target posture, the chuck 5 holds the workpiece 4 (step 305). For example, the chuck 5 holds the workpiece 4 by clamping the workpiece 4 with a plurality of jaws that constitute the chuck 5 closing.

[0029] Here, if the posture of the hand 2 when all the jaws of the chuck 5 are in contact with the workpiece 4 and holding the workpiece 4 (also referred to as the mounting posture) is exactly the same as the target posture for workpiece supply, no force is generated to move the workpiece 4 when the chuck 5 holds the workpiece 4, and no external force is applied to the hand 2.

[0030] On the other hand, when the attachment posture deviates from the workpiece supply target posture, an external force that tries to move the hand 2 from the workpiece supply target posture to the attachment posture is applied to the hand 2, and the external force is measured by the force sensor 3. The magnitude of this external force indicates the magnitude of the deviation between the attachment posture and the workpiece supply target posture.

[0031] The force feedback correcting unit 211 determines whether the measurement value of the force sensor 3 is smaller than a predetermined threshold value included in the threshold value information 225 (step 306). This threshold value may be an end threshold value Tf (see FIG. 9) for force feedback correction included in the threshold value information 225. The same applies to the determination in step 315 described below. Then, if the measurement value of the force sensor 3 is not smaller than the threshold value (step 306: No), the force feedback correcting unit 211 performs force feedback correction (step 307).

[0032] For example, the force feedback correction unit 211 may control the robot arm 1 to move the hand 2 by a small distance to search for a direction in which the measurement value of the force sensor becomes smaller (i.e., the external force acting on the hand 2 becomes smaller), and move the hand 2 in that direction until the measurement value of the force sensor becomes smaller than a threshold value. As this method can be applied to any known method, such as the method described in JP 2021-109295 A, a detailed description thereof will be omitted.

[0033] When the measurement value of the force sensor becomes smaller than the threshold value, the robot posture acquisition unit 212 acquires the posture of the robot arm 1 and hand 2 at that time and stores it as attachment posture information 221 (step 308). Then, the path generation unit 218 generates a path from the attachment posture to the evacuation position (step 309). The control unit 219 controls the hand 2 to release the workpiece 4, and controls the robot arm 1 to evacuate to the evacuation position (step 310).

[0034] When the retreat is completed, the processing machine starts processing the workpiece 4 (step 311). The control unit 219 waits to receive a processing end signal from the processing machine (step 312), and when processing is completed (step 312: Yes), controls the robot arm 1 so that the hand 2 moves again to the attachment posture (step 313), and controls the hand 2 so that it grips the workpiece 4 (step 314).

[0035] Next, the force feedback correction unit 211 determines whether the measurement value of the force sensor 3 is smaller than a predetermined threshold value included in the threshold value information 225 (step 315). If the measurement value of the force sensor 3 is not smaller than the threshold value (step 315: No), the force feedback correction unit 211 performs force feedback correction (step 316). These are executed in the same manner as steps 306 and 307 described above.

[0036] When the measurement value of the force sensor becomes smaller than the threshold value, the robot posture acquisition unit 212 acquires the posture of the robot arm 1 and hand 2 at that time and saves it as removal posture information 222 (step 317). For example, if the processing machine is a lathe, a cylinder centered on the rotation axis of the chuck 5 is cut out by processing, so the removal posture acquired when removing the processed workpiece 4 is the correct work supply posture (i.e., the posture that is desirable to be set as the work supply target posture). Similarly, in the case of processing machines other than lathes (for example, end mill machines), the removal posture of the processed workpiece 4 is the correct work supply posture.

[0037] Next, the workpiece dimension error calculation unit 214 calculates the difference between the mounting posture calculated in step 308 and the removal posture calculated in step 317, thereby calculating the workpiece dimension error, and stores the calculated workpiece dimension error as workpiece dimension error information 224 (step 318).

[0038] Next, the path generating unit 218 generates a path from the removal posture to the storage position of the machined workpiece 4 (step 319). The control unit 219 controls the robot arm 1 to move the workpiece 4 to the storage position (step 320), and releases the workpiece 4 (step 321).

[0039] Next, the workpiece supply target attitude information update unit 213 judges whether to update the workpiece supply target attitude (step 322), and if it is judged that the workpiece supply target attitude should be updated (step 322: Yes), it updates the workpiece supply target attitude (step 323). Details of the judgment in step 322 and the update in step 323 will be described later with reference to FIG. 6 etc.

[0040] Next, the abnormality determination unit 216 determines whether the workpiece is abnormal (step 324). If it is determined that the workpiece is abnormal (step 324: Yes), the abnormality determination unit 215 issues an alarm (step 325) and stops the equipment (e.g., the processing machine) (step 326). Details of the determination in step 324 will be described later with reference to FIG. 7, etc.

[0041] Although the process after it is determined that an abnormality exists will not be described in detail in this embodiment, for example, the processing machine may be automatically stopped, or an alarm may be output to the user as described later. This allows, for example, inspection of the equipment or the manufacturing process of the workpiece to be performed.

[0042] FIG. 4 is an explanatory diagram showing a first example of processing to which the workpiece supply system 100 according to the embodiment of the present invention is applied.

[0043] Fig. 4 shows turning as a first example. Specifically, Fig. 4 shows a front view (a) and a side view (b) of the chuck 5 when the processing machine is a turning machine. Here, the chuck 5 of the turning machine is referred to as chuck 5A, and the workpiece 4 to be turned and held by the chuck 5A is referred to as workpiece 4A. The front view shows the chuck 5A as seen from the direction on the rotation axis where the workpiece 4A is supplied.

[0044] The disk-shaped chuck 5A has a plurality of chuck jaws 401. In the example of FIG. 4, three chuck jaws 401 are provided, and move in the radial direction along the surface that holds the workpiece 4A to grip the workpiece 4A. Before gripping the workpiece 4A, each chuck jaw 401 is located away from the rotation axis of the chuck 5A. After the hand 2 (not shown in FIG. 4) moves the workpiece 4A to the workpiece supply target posture, each chuck jaw 401 moves in the direction of the rotation axis to grip the workpiece 4A (step 305). At this time, the workpiece 4A may move from the posture in which it was supplied due to the movement of the chuck jaws 401. In that case, the posture of the hand 2 is corrected according to the external force applied to the hand 2 by the movement, and the corrected value is stored as the mounting posture (steps 306 to 308). Then, processing is started (step 311).

[0045] In the example of FIG. 4, the workpiece 4A before machining is generally cylindrical, but since it is before machining, it may have irregularities such as unevenness on the surface. In the example of FIG. 4, the workpiece 4A before machining is generally elliptical cylindrical. This workpiece 4A is held in a chuck 5A and rotated to perform cutting. The part of the workpiece 4A after cutting has a cylindrical shape with a smaller diameter than the workpiece 4A before machining, and the center of the cylinder coincides with the rotation axis 404 of the chuck 5A. The shaded parts shown in the front view (a) and the side view (b) indicate the post-machining shape 403, which is the shape of the workpiece 4A after cutting, and the dashed part shown in the side view (b) indicates the pre-machining shape 402, which is the shape of the workpiece 4A before cutting.

[0046] As described above, the posture of the processed workpiece 4A is constant regardless of the deviation of the workpiece supply posture and the change in the shape of the workpiece 4A before processing, etc. Therefore, the posture of the hand 2 when gripping the processed workpiece 4 held by the chuck 5 is a desirable posture as the workpiece supply target posture.

[0047] The center 405 of the workpiece 4A before cutting does not necessarily coincide with the rotation axis 404 of the chuck 5A. The deviation 406 between the two at this time corresponds to the difference between the mounting posture stored in step 308 and the removal posture stored in step 317, and this is calculated and stored as the workpiece dimensional error (step 318).

[0048] FIG. 5 is an explanatory diagram showing a second example of processing to which the workpiece supply system 100 according to the embodiment of the present invention is applied.

[0049] Fig. 5 shows end mill machining as a second example. Specifically, Fig. 5 shows a plan view (a) and a front view (b) of the chuck 5 when the processing machine is an end mill machine. Here, the chuck 5 of the end mill machine is referred to as chuck 5B, and the workpiece 4 to be end milled and held by chuck 5B is referred to as workpiece 4B.

[0050] The chuck 5B has a plurality of chuck jaws 501. In the example of FIG. 5, four chuck jaws 501 are provided, and move along the surface that holds the workpiece 4B to grip the workpiece 4B. Before gripping the workpiece 4B, each chuck jaw 501 is located away from the rotation axis of the chuck 5B. After the hand 2 (omitted in FIG. 5) moves the workpiece 4B to the workpiece supply target posture, each chuck jaw 501 moves to grip the workpiece 4A (step 305). At this time, the workpiece 4B may move from the posture in which it was supplied due to the movement of the chuck jaws 501. In that case, the posture of the hand 2 is corrected according to the external force applied to the hand 2 by the movement, and the corrected value is stored as the mounting posture (steps 306 to 308). Then, processing is started (step 311).

[0051] In the example of Fig. 5, the workpiece 4B before machining has a rectangular parallelepiped shape, but since it is before machining, it may have irregularities such as unevenness on the surface. This workpiece 4B is held in a chuck 5B and cut by an end mill machine. The cut portion of the workpiece 4B has a rectangular parallelepiped shape that is smaller than the workpiece 4B before machining. The shaded area shown in the plan view (a) and the front view (b) indicates the cut shape 503 of the workpiece 4B after cutting, and the dashed area shown in the front view (b) indicates the pre-machining shape 502 of the workpiece 4B before cutting.

[0052] As in the example of lathe machining shown in FIG. 4, the posture of the workpiece 4B after machining is a desirable posture as the workpiece supply target posture.

[0053] The center line 505 of the workpiece 4B before cutting does not necessarily coincide with the center line 504 of the workpiece 4B after cutting. The deviation 506 between the two at this time corresponds to the difference between the mounting attitude stored in step 308 and the removal attitude stored in step 317, and this is calculated and stored as the workpiece dimensional error (step 318).

[0054] FIG. 6 is an explanatory diagram showing an example of workpiece supply target posture update executed by the robot control device 14 according to the embodiment of the present invention.

[0055] Fig. 6 shows an example of the relationship between the target posture when the robot control device 14 supplies the workpiece 4 to the chuck 5, i.e., the workpiece supply target posture, and the actual mounting posture. In reality, both the workpiece supply target posture and the mounting posture are expressed as six-dimensional values ​​consisting of X coordinates, Y coordinates, Z coordinates, roll angle, pitch angle, and yaw angle, but for the sake of explanation, Fig. 6 shows them plotted in a two-dimensional space.

[0056] In the example of Fig. 6, the black dots indicate the workpiece supply target posture, which is set as the target in step 304. Meanwhile, the white dots indicate the attachment posture saved in step 308. If it is determined in step 306 that the force sensor value is equal to or greater than the threshold value, this is the value after force feedback correction in step 307 is performed.

[0057] Every time the workpiece 4 is supplied, the mounting posture of the workpiece 4 is saved in step 308. The multiple white dots in Fig. 6 are an example of plotting multiple past mounting postures. In step 322, the workpiece supply target posture information update unit 213 determines whether the relationship between the current workpiece supply target posture (black dots) and the distribution of multiple past mounting postures (white dots) satisfies a predetermined condition, and if so, may update the current workpiece supply target posture to a new workpiece supply target posture in step 323.

[0058] For example, when the magnitude of an error vector from the current workpiece supply target posture to the center of distribution of a predetermined number of past mounting postures exceeds a predetermined threshold, the current workpiece supply target posture may be updated to a new workpiece supply target posture (step 322: Yes, step 323). Here, the new workpiece supply target posture may be the center of distribution of a predetermined number of past mounting postures. Also, the threshold for judgment in step 322 may be, for example, a judgment threshold value Tp (see FIG. 9) for updating the workpiece supply target posture included in the threshold information 225.

[0059] FIG. 7 is an explanatory diagram showing an example of a workpiece abnormality determination executed by the robot control device 14 according to the embodiment of the present invention.

[0060] The horizontal axis of the graph shown in Fig. 7 is the number of machining points of the workpiece 4, and the vertical axis is the central coordinate of the distribution of the workpiece dimensional error. The solid line plotted on the graph in Fig. 7 is the central coordinate of the distribution of the workpiece dimensional error of the past 100 points, and the dashed line is the central coordinate of the distribution of the workpiece dimensional error of the past 1000 points. Note that in reality, the workpiece dimensional error is expressed as a six-dimensional value consisting of X coordinate, Y coordinate, Z coordinate, roll angle, pitch angle, and yaw angle.

[0061] 3A and 3B are executed each time a new workpiece 4 is machined, and the workpiece dimensional error is calculated and stored in step 318. Then, corresponding to the number of machining points obtained by adding 1 to the number of machining points in the previous machining, the distribution center of the workpiece dimensional error calculated in a predetermined number of machining operations (e.g., 100 times) up to that point is plotted as a solid line graph. Also, the distribution center of the workpiece dimensional error calculated in an even larger number of machining operations (e.g., 1000 times) up to that point is plotted as a dashed line graph.

[0062] The workpiece dimensional error is the difference between the mounting posture acquired in step 308 and the removal posture acquired in step 317. A change in this workpiece dimensional error means a change in the shape of the workpiece 4 before machining. The shape of the workpiece 4 before machining may change suddenly or gradually. The abnormality determination unit 216 determines a workpiece abnormality based on the degree of change in the shape of the workpiece 4 before machining detected based on the distribution of the workpiece dimensional error (step 324).

[0063] For example, if the workpiece 4 before machining is a casting, the shape of the workpiece 4 before machining gradually changes due to gradual deterioration of the mold. Such gradual changes can be detected by comparing the distribution center of the workpiece dimensional errors of the past 100 times with the distribution center of the workpiece dimensional errors of the past 1000 times. For example, if the magnitude of the error vector between the distribution center of the workpiece dimensional errors of the past 100 times and the distribution center of the workpiece dimensional errors of the past 1000 times exceeds a predetermined threshold value, it may be determined that the workpiece is abnormal (step 324: Yes). This threshold value may be, for example, a determination threshold value Twc for the workpiece dimensional error transition included in the threshold value information 225 (see FIG. 9).

[0064] Alternatively, when the casting mold is suddenly deteriorated or replaced with a new one, the shape of the workpiece 4 before machining changes suddenly. Such a sudden change can be detected by comparing the newly acquired workpiece dimensional error with the distribution of the workpiece dimensional error acquired up to that point. For example, when the magnitude of the error vector between the newly acquired workpiece dimensional error and the distribution center of the workpiece dimensional error of a predetermined number of times in the past (for example, 100 times) is equal to or greater than a predetermined threshold value, or when the newly acquired workpiece dimensional error is away from the distribution center of the workpiece dimensional error of a predetermined number of times in the past by 3σ or more of the distribution, the workpiece may be determined to be abnormal (step 324: Yes). This threshold value may be, for example, the abnormality determination threshold value Tws of the workpiece dimensional error variation included in the threshold value information 225 (see FIG. 9).

[0065] Note that the above "100 times" and "1000 times" are both examples, and other numbers may be used. For example, "100 times" is an example of a sufficient number of samples to reduce the effects of measurement noise and workpiece dimensional variations. Also, "1000 times" is an example of a number of samples that is sufficiently greater than the above "100 times." The same applies to the following explanation.

[0066] In the above example, a workpiece abnormality is detected based on the distribution of workpiece dimensional errors, but the abnormality determination unit 216 can also detect an equipment abnormality based on the distribution of removal postures. Detection of equipment abnormality will be described below.

[0067] As explained with reference to FIG. 4 etc., the posture of the workpiece 4 after machining is constant and is not dependent on deviations in the workpiece supply posture or variations in the shape of the workpiece 4A before machining. If the removal posture changes despite this, it means that some change has occurred on the equipment side. Specifically, a change in the removal posture occurs, for example, when the claws of the hand 2 for gripping the workpiece 4 are deformed due to an excessive load or the like. Such equipment abnormalities can be detected based on the distribution of the removal postures.

[0068] In this case, the vertical axis of the graph in Fig. 7 is the central coordinate of the distribution of the removal postures. Each time a new workpiece 4 is machined, the processes in Fig. 3A and Fig. 3B are executed, and the removal posture is acquired and stored in step 317. Then, corresponding to the number of machining points obtained by adding 1 to the number of machining points in the previous machining, the distribution center of the removal postures acquired in the 100 machining operations up to that point is plotted as a solid line graph. Also, the distribution center of the removal postures calculated in the past 1000 machining operations up to that point is plotted as a dashed line graph.

[0069] The state of the equipment that causes the variation in the removal posture (for example, the state of the claws of the hand 2) may change gradually or suddenly. The abnormality determination unit 216 determines an equipment abnormality based on the state of the equipment detected based on the distribution of the removal posture (step 324).

[0070] For example, a gradual change in the state of the equipment can be detected by comparing the distribution center of the past 100 removal postures with the distribution center of the past 1000 removal postures. For example, if the magnitude of the error vector between the distribution center of the past 100 removal postures and the distribution center of the past 1000 removal postures exceeds a predetermined threshold, it may be determined that the equipment is abnormal (step 324: Yes). This threshold may be, for example, an abnormality determination threshold Trc of the removal posture error center position included in the threshold information 225 (see FIG. 9).

[0071] Furthermore, a sudden change in the state of the equipment can be detected by comparing the newly acquired removal posture with the distribution of removal postures acquired up to that point. For example, if the magnitude of the error vector between the newly acquired removal posture and the distribution center of the removal postures of a predetermined number of past times (e.g., 100 times) is equal to or greater than a predetermined threshold value, or if the newly acquired removal posture is away from the distribution center of the removal postures of a predetermined number of past times by 3σ or more of the distribution, it may be determined that the equipment is abnormal (step 324: Yes). This threshold value may be, for example, an abnormality determination threshold value Trs of the removal posture error variation included in the threshold value information 225 (see FIG. 9).

[0072] FIG. 8 is an explanatory diagram showing examples of attachment attitude information 221, removal attitude information 222, work supply target attitude information 223, and work size error information 224 held by the robot control device 14 in the embodiment of the present invention.

[0073] The mounting attitude information 221, the removal attitude information 222, the workpiece supply target attitude information 223, and the workpiece dimension error information 224 are all stored as information of the same format in the storage unit 22. Here, the mounting attitude information 221 will be described as an example.

[0074] The mounting attitude information 221 includes an identification number 801 , an x ​​coordinate value 802 , a y coordinate value 803 , a z coordinate value 804 , a roll angle 805 , a pitch angle 806 , and a yaw angle 807 .

[0075] The identification number 801 is a serial number of a set of posture information included in the mounting posture information 221. The identification number 801 may be, for example, the identification information of each workpiece 4. The x coordinate value 802, the y coordinate value 803, the z coordinate value 804, the roll angle 805, the pitch angle 806, and the yaw angle 807 indicate the mounting posture of each workpiece 4. That is, force feedback correction is performed for each workpiece 4 as necessary (step 307), and when the force sensor value becomes smaller than a predetermined threshold value (step 306: Yes), the coordinate values ​​and angles indicating the posture of the hand 2 at that time are held as the x coordinate value 802, the y coordinate value 803, the z coordinate value 804, the roll angle 805, the pitch angle 806, and the yaw angle 807.

[0076] The formats of the removal attitude information 222, the workpiece supply target attitude information 223, and the workpiece dimension error information 224 are also the same as those described above. For example, the coordinate values ​​and angles indicating the attitude of the hand 2 acquired in step 317 are held as the x coordinate value 802, the y coordinate value 803, the z coordinate value 804, the roll angle 805, the pitch angle 806, and the yaw angle 807 of the removal attitude information 222. In addition, the coordinate values ​​and angles indicating the attitude of the hand 2 when supplying each workpiece 4 to the chuck 5, which are set in advance, are held as the x coordinate value 802, the y coordinate value 803, the z coordinate value 804, the roll angle 805, the pitch angle 806, and the yaw angle 807 of the workpiece supply target attitude information 223. These coordinate values ​​and angles are updated when it is determined in step 322 that the workpiece supply target attitude is to be updated.

[0077] In addition, the coordinate values ​​and angles indicating the posture of the hand 2 corresponding to the workpiece dimension error calculated in step 318 (for example, the difference between the coordinate values ​​and angles indicating the removal posture acquired in step 317 and the coordinate values ​​and angles indicating the attachment posture acquired in step 308) are retained as the x coordinate value 802, y coordinate value 803, z coordinate value 804, roll angle 805, pitch angle 806, and yaw angle 807 of the workpiece dimension error information 224.

[0078] In the above example, the coordinate values ​​and angles indicating the posture of the hand 2 are stored, but instead, information such as the joint angles of the robot arm 1 may be stored.

[0079] FIG. 9 is an explanatory diagram showing an example of the threshold information 225 held by the robot control device 14 according to the embodiment of the present invention.

[0080] The threshold information 225 includes, for example, an end threshold (Tf) for force feedback correction, a judgment threshold (Tp) for updating the work supply target posture, an abnormality judgment threshold (Trs) for removal posture error variation, an abnormality judgment threshold (Trc) for removal posture error center position, an abnormality judgment threshold (Tws) for work dimension error variation, and a judgment threshold (Twc) for the work dimension error trend.

[0081] As the end threshold (Tf) of the force feedback correction, a threshold value of the magnitude of the external force measured by the force sensor 3, such as 1 N, is registered. As the judgment threshold (Tp) for updating the workpiece supply target posture, the abnormality judgment threshold (Trs) for judging an abnormality of the removal posture error variation, the abnormality judgment threshold (Trc) for judging an abnormality of the removal posture error center position, the abnormality judgment threshold (Tws) for judging the workpiece dimension error variation, and the judgment threshold (Twc) for judging the workpiece dimension error transition, threshold values, such as 3 mm, 4 mm, etc., used for comparing the posture value and the posture distribution value, or comparing the posture value distributions, are registered.

[0082] The storage unit 22 of the robot control device 14 further holds environmental information 226 and robot information 227. The environmental information 226 includes, for example, three-dimensional model information of processing machines and peripheral devices (e.g., conveyors and shelves). The robot information 227 includes three-dimensional model information of the robot arm 1 and hand 2, and information indicating the movable range of the joint angles of the robot arm 1. The above three-dimensional model information may be in a general format used in, for example, CAD. Illustrations and detailed descriptions of this information are omitted.

[0083] FIG. 10 is an explanatory diagram showing a first example of information output by the robot control device 14 according to the embodiment of the present invention.

[0084] A screen 1000 shown in FIG. 10 is an example of a screen displayed by the display unit 25 of the robot control device 14, and includes, for example, a work dimension error distribution display button 1001, a removal posture error distribution display button 1002, an equipment abnormality alarm display unit 1003, a work abnormality alarm display unit 1004, a force sense abnormality alarm display unit 1005, an error distribution display unit 1006, an error trend display unit 1007, a force sensor value display unit 1008, a threshold value display unit 1009, a threshold value change button 1010, an environment setting button 1011, and a work supply target posture setting button 1012.

[0085] A workpiece dimension error distribution display button 1001 and a removal posture error distribution display button 1002 are operated by the user to select display of either the distribution of workpiece dimension errors or the distribution of removal posture errors. Fig. 10 shows an example in which the removal posture error distribution display button 1002 is operated.

[0086] In this case, the error distribution display unit 1006 displays the distribution of errors in the removal posture previously acquired in step 317. In the example of Fig. 10, the x-coordinate value and the y-coordinate value of the removal posture are plotted in a two-dimensional space, but a combination of two other coordinate values ​​or a combination of any of the roll angle, pitch angle, and yaw angle may be used. Also, for example, a perspective view of a three-dimensional space in which three-dimensional coordinate values ​​are plotted may be displayed.

[0087] In the example of Fig. 10, when a change in the workpiece supply target attitude is made (step 323), the removal attitude acquired before the change is displayed as black dots, and the removal attitude acquired after the change is displayed as white dots. In addition, the degree of deviation of the distribution before and after the change (for example, the amount of deviation between the distribution centers) and the magnitude of the variation of each distribution may be displayed. By comparing these, the effect of the change in the workpiece supply target attitude can be confirmed.

[0088] The error transition display section 1007 displays a graph with the number of processing points on the horizontal axis and the removal posture error calculated in step 317 on the vertical axis. As shown in Fig. 7, the distribution center of the errors in the removal postures of the past 100 points may be displayed by a solid line, and the distribution center of the errors in the removal postures of the past 1000 points may be displayed by a dashed line.

[0089] The error transition display unit 1007 may display a graph of the magnitude of the error vector between the distribution center of the past 100 removal postures and the distribution center of the past 1000 removal postures. Furthermore, an abnormality determination threshold (Trc) of the removal posture error center position may be displayed, and, for example, when the difference between the distribution center of the errors of the past 100 removal postures and the distribution center of the errors of the past 1000 removal postures becomes equal to or larger than the abnormality determination threshold (Trc) of the removal posture error center position, it may be determined that an equipment abnormality has occurred, and an alarm may be displayed in the equipment abnormality alarm display unit 1003.

[0090] The force sensor value display unit 1008 displays a graph with the number of machining points on the horizontal axis and the measurement values ​​of the force sensor 3 acquired in steps 306 and 315 on the vertical axis. The force sensor value display unit 1008 further displays the end threshold value (Tf) of the force feedback correction. For example, when the measurement value of the force sensor 3 becomes equal to or greater than the end threshold value (Tf) of the force feedback correction, an alarm may be displayed in the force sense abnormality alarm display unit 1005.

[0091] The threshold value display section 1009 displays the threshold values ​​for each item similar to those shown in FIG.

[0092] A user can operate threshold change button 1010 to change the threshold of any item included in threshold information 225. For example, operating threshold change button 1010 may transition to another screen (not shown) where the user can manually change the threshold. Alternatively, the user may input a desired threshold in threshold display section 1009 and operate threshold change button 1010 to set the threshold.

[0093] Furthermore, the user can operate the environment setting button 1011 to set the environment information 226. For example, the user may input a three-dimensional model of the facility including the work supply device 10, the work 4, and the like.

[0094] Furthermore, the user can set the workpiece supply target posture to an arbitrary value by operating the workpiece supply target posture setting button 1012. For example, by operating the workpiece supply target posture setting button 1012, a transition to another screen (not shown) may be made, where the user inputs the workpiece supply target posture. At this time, a recommended value calculated from the deviation amount of the center of the distribution of the removal postures may be displayed. For example, the center of the distribution of the removal postures may be set as the recommended value for a new workpiece supply target posture.

[0095] FIG. 11 is an explanatory diagram showing a second example of information output by the robot control device 14 according to the embodiment of the present invention.

[0096] The differences from FIG. 10 will be described below.

[0097] Fig. 11 shows an example in which the workpiece dimension error distribution display button 1001 is operated. In this case, the error distribution display section 1006 displays the distribution of the workpiece dimension errors previously acquired in step 318. In the example of Fig. 11, the x-coordinate value and the y-coordinate value of the workpiece dimension errors are plotted in a two-dimensional space, but a combination of two other coordinate values ​​or any combination of a roll angle, a pitch angle, and a yaw angle may be used. Also, for example, a perspective view of a three-dimensional space in which three-dimensional coordinate values ​​are plotted may be displayed.

[0098] 11, when the workpiece supply target attitude is changed (step 323), the workpiece dimensional error acquired before the change is displayed as black dots, and the workpiece dimensional error acquired after the change is displayed as white dots. By comparing these, the effect of changing the workpiece supply target attitude can be confirmed.

[0099] The error transition display section 1007 displays a graph with the horizontal axis representing the number of machining points and the vertical axis representing the workpiece dimensional error calculated in step 318. As shown in Fig. 7, the distribution center of the workpiece dimensional error for the past 100 points may be displayed by a solid line, and the distribution center of the workpiece dimensional error for the past 1000 points may be displayed by a dashed line.

[0100] The error transition display unit 1007 may display a graph of the magnitude of the error vector between the distribution center of the past 100 removal postures and the distribution center of the past 1000 removal postures. Furthermore, a judgment threshold value (Twc) for the workpiece dimensional error transition is displayed, and, for example, when the difference between the distribution center of the workpiece dimensional error of the past 100 points and the distribution center of the workpiece dimensional error of the past 1000 points becomes equal to or greater than the judgment threshold value (Twc) for the workpiece dimensional error transition, it is judged that a workpiece abnormality has occurred, and an alarm may be displayed in the workpiece abnormality alarm display unit 1004.

[0101] Furthermore, the system according to the embodiment of the present invention may be configured as follows.

[0102] (1) A robot control device (e.g., a robot control device 14) for controlling a robot (e.g., a work supply device 10 including a robot arm 1 and a hand 2) that mounts and removes a work (e.g., a work 4) on a processing machine, the robot control device including: a correction unit (e.g., a force feedback correction unit 211) that corrects the posture of the robot based on a measurement value of a sensor (e.g., a force sensor 3) that measures the load of the robot; a robot posture acquisition unit (e.g., a robot posture acquisition unit 212) that acquires the posture of the robot; a memory unit (e.g., a memory unit 22) that stores the posture of the robot acquired by the robot posture acquisition unit; and a work mounting target posture generation unit (e.g., a work supply target posture update unit 23) that generates a work mounting target posture, which is a target posture for mounting the work on the processing machine. 13), and a path generating unit (e.g., path generating unit 218) which generates an operation of the robot according to the workpiece mounting target posture, in which the correction unit corrects the posture of the robot so that the load of the robot becomes smaller than a preset threshold when the robot grasps the workpiece after processing by the processing machine (e.g., steps 315, 316), the robot posture acquisition unit acquires removal postures, which are the corrected postures of the robot, for the multiple workpieces after processing and stores them in the memory unit (e.g., step 317), and the workpiece mounting target posture generation unit generates a new workpiece mounting target posture (e.g., a new workpiece supply target posture) based on the multiple removal postures stored in the memory unit (e.g., step 323).

[0103] This makes it possible to correct deviations in the posture of the workpiece being supplied by the robot while continuing production using the workpiece to be machined.

[0104] (2) The robot control device according to (1) above, further comprising an abnormality determination unit (e.g., the abnormality determination unit 216) that determines an abnormality in equipment including the robot based on a change in the removal posture.

[0105] This makes it possible to detect equipment abnormalities.

[0106] (3) In the robot control device described in (2) above, the abnormality determination unit determines that the equipment is abnormal (e.g., step 324) when the newly acquired removal posture is farther away from the distribution of the multiple past removal postures than a predetermined criterion (for example, when the newly acquired removal posture is farther away from the center of distribution of the past removal postures by 3σ or more, or when the magnitude of the difference between the newly acquired removal posture and the center of distribution of the past removal postures exceeds a predetermined threshold).

[0107] This makes it possible to detect equipment abnormalities based on sudden changes in the equipment condition.

[0108] (4) In the robot control device described in (2) above, the abnormality determination unit determines that the equipment is abnormal when the distribution of a first predetermined number (e.g., 100) of past removal postures deviates from the distribution of a second predetermined number (e.g., 1,000) of past removal postures that is greater than the first predetermined number by a predetermined criterion (e.g., when the magnitude of the difference between the centers of both distributions exceeds a predetermined threshold value) (e.g., step 324).

[0109] This makes it possible to detect equipment abnormalities based on gradual changes in the equipment condition.

[0110] (5) In the robot control device described in (2) above, when it is determined that the equipment is abnormal, the abnormality determination unit outputs an alarm indicating the abnormality of the equipment (for example, step 325).

[0111] This allows users to be notified of equipment abnormalities, leading to the development of countermeasures.

[0112] (6) In the robot control device described in (1) above, the correction unit corrects the posture of the robot so that the load on the robot is reduced when the robot moves the workpiece before processing to a workpiece mounting target posture and the holding device of the processing machine holds the workpiece before processing (e.g., steps 304 to 307), the robot posture acquisition unit acquires a mounting posture, which is the corrected posture of the robot, for each of the plurality of workpieces before processing and stores it in the memory unit (e.g., step 308), and the robot control device further has a workpiece dimensional error calculation unit (e.g., workpiece dimensional error calculation unit 214) that calculates a workpiece dimensional error based on a difference between the mounting posture and the removal posture, and an abnormality judgment unit (e.g., abnormality judgment unit 216) that judges an abnormality of the workpiece based on the workpiece dimensional error.

[0113] This makes it possible to detect abnormalities in the workpiece.

[0114] (7) In the robot control device described in (6) above, the abnormality judgment unit judges that the work is abnormal (e.g., step 324) when the newly acquired work dimensional error is farther away from the distribution of the multiple past work dimensional errors than a predetermined criterion (for example, when the newly acquired work dimensional error is farther away from the center of distribution of the past work dimensional errors by 3σ or more, or when the magnitude of the difference between the newly acquired work dimensional error and the center of distribution of the past work dimensional errors exceeds a predetermined threshold).

[0115] This makes it possible to detect workpiece abnormalities based on sudden changes in the workpiece condition.

[0116] (8) In the robot control device described in (6) above, the abnormality judgment unit judges that the workpiece is abnormal (e.g., step 324) when the distribution of the workpiece dimensional errors for a first predetermined number of past data (e.g., 100) is deviated from the distribution of the workpiece dimensional errors for a second predetermined number of past data (e.g., 1000) that is greater than the first predetermined number by a predetermined criterion (e.g., when the magnitude of the difference between the centers of the two distributions exceeds a predetermined threshold value).

[0117] This makes it possible to detect workpiece abnormalities based on gradual changes in the workpiece condition.

[0118] (9) In the robot control device described in (6) above, when the abnormality determination unit determines that the workpiece is abnormal, it outputs an alarm indicating the abnormality of the workpiece (e.g., step 325).

[0119] This allows the user to be notified of work abnormalities, leading to the development of appropriate countermeasures.

[0120] (10) In the robot control device described in (1) above, the sensor is a sensor that outputs a signal indicating the magnitude of an external force acting on a hand of the robot that grips the workpiece.

[0121] This makes it possible to measure the load on the robot.

[0122] (11) In the robot control device described in (10) above, the sensor is a force sensor, a pressure sensor, an image sensor or a strain gauge.

[0123] This makes it possible to measure the load on the robot.

[0124] (12) In the robot control device described in (1) above, the workpiece mounting target posture generation unit generates a center of distribution of the multiple removal postures stored in the memory unit as the new workpiece mounting target posture.

[0125] This allows the workpiece mounting target attitude to be appropriately updated.

[0126] The present invention is not limited to the above-mentioned embodiment, but includes various modifications. For example, the above-mentioned embodiment has been described in detail for a better understanding of the present invention, and is not necessarily limited to those including all of the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Also, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0127] In addition, the above-mentioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware, for example, by designing them as integrated circuits. In addition, the above-mentioned configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function. Information such as a program, table, file, etc. that realizes each function can be stored in a storage device such as a non-volatile semiconductor memory, a hard disk drive, or an SSD (Solid State Drive), or in a computer-readable non-transitory data storage medium such as an IC card, an SD card, or a DVD.

[0128] In addition, the control lines and information lines are shown as those considered necessary for the explanation, and not all control lines and information lines in the product are shown. In reality, it can be considered that almost all components are connected to each other. [Explanation of symbols]

[0129] 1. Robot arm 2. Hand 3. Force sensor 4. Work 5. Chuck 10. Work supply device 12...Work instruction device 14. Robot control device 100 Work supply system

Claims

1. A robot control device that controls a robot that mounts and removes a workpiece on a processing machine, a correction unit that corrects a posture of the robot based on a measurement value of a sensor that measures a load of the robot; a robot posture acquisition unit for acquiring a posture of the robot; a storage unit for storing the posture of the robot acquired by the robot posture acquisition unit; a workpiece mounting target posture generating unit that generates a workpiece mounting target posture, which is a target posture for mounting the workpiece on the processing machine; a path generating unit that generates a motion of the robot according to the workpiece mounting target posture, the correction unit corrects a posture of the robot so that a load on the robot becomes smaller than a preset threshold value when the robot grips the workpiece after processing by the processing machine; the robot posture acquisition unit acquires a removal posture, which is a posture of the robot after correction, for each of the plurality of workpieces after machining and stores the acquired posture in the storage unit; The robot control device is characterized in that the workpiece mounting target posture generation unit generates a new workpiece mounting target posture based on the multiple removal postures stored in the memory unit.

2. The robot control device according to claim 1 , The robot control device further comprises an abnormality determination unit that determines an abnormality in equipment including the robot based on a change in the removal posture.

3. The robot control device according to claim 2, The robot control device is characterized in that the abnormality determination unit determines that the equipment is abnormal when the newly acquired removal posture deviates from a distribution of multiple past removal postures by more than a predetermined criterion.

4. The robot control device according to claim 2, the abnormality determination unit determines that the equipment is abnormal when a distribution of a first predetermined number of past removal postures deviates by more than a predetermined criterion from a distribution of a second predetermined number of past removal postures that is greater than the first predetermined number.

5. The robot control device according to claim 2, The robot control device is characterized in that the abnormality determination unit outputs an alarm indicating an abnormality in the equipment when it determines that the equipment is abnormal.

6. The robot control device according to claim 1 , the correction unit corrects a posture of the robot so that a load on the robot is reduced when the robot moves the unmachined workpiece to a workpiece mounting target posture and a holding device of the processing machine holds the unmachined workpiece; the robot posture acquisition unit acquires an attachment posture, which is a posture of the robot after correction, for each of the plurality of workpieces before machining and stores the acquired attachment posture in the storage unit; The robot control device includes: a workpiece dimensional error calculation unit that calculates a workpiece dimensional error based on a difference between the mounting posture and the removal posture; and an abnormality determination unit that determines an abnormality in the workpiece based on the workpiece dimensional error.

7. The robot control device according to claim 6, The robot control device is characterized in that the abnormality judgment unit judges that the workpiece is abnormal when the newly acquired workpiece dimensional error deviates from the distribution of multiple past workpiece dimensional errors by more than a predetermined standard.

8. The robot control device according to claim 6, The robot control device is characterized in that the abnormality judgment unit judges that the workpiece is abnormal when the distribution of a first predetermined number of past workpiece dimensional errors deviates by more than a predetermined standard from the distribution of a second predetermined number of past workpiece dimensional errors that is greater than the first predetermined number.

9. The robot control device according to claim 6, The robot control device is characterized in that the abnormality determination unit outputs an alarm indicating an abnormality in the workpiece when it determines that the workpiece is abnormal.

10. The robot control device according to claim 1 , A robot control device characterized in that the sensor is a sensor that outputs a signal indicating the magnitude of an external force acting on a hand of the robot that grips the workpiece.

11. The robot control device according to claim 10, A robot control device, wherein the sensor is a force sensor, a pressure sensor, an image sensor or a strain gauge.

12. The robot control device according to claim 1 , The robot control device according to claim 1, wherein the workpiece mounting target posture generation unit generates a center of distribution of the plurality of removal postures stored in the memory unit as the new workpiece mounting target posture.

13. A robot control method executed by a robot control device that controls a robot that mounts and removes a workpiece on a processing machine, comprising: a correction step in which the robot control device corrects the posture of the robot based on a measurement value of a sensor that measures a load of the robot; a robot posture acquisition step in which the robot control device acquires and stores a posture of the robot; a workpiece mounting target posture generating step in which the robot control device generates a workpiece mounting target posture which is a target posture for mounting the workpiece on the processing machine; a path generation procedure in which the robot control device generates a motion of the robot according to the workpiece mounting target posture, In the correction step, the robot control device corrects a posture of the robot when the robot grips the workpiece after processing by the processing machine so that a load on the robot becomes smaller than a preset threshold value; In the robot posture acquisition step, the robot control device acquires and stores a removal posture, which is a posture of the robot after correction, for each of the plurality of workpieces after machining; A robot control method, characterized in that in the workpiece mounting target posture generating procedure, the robot control device generates a new workpiece mounting target posture based on a plurality of the stored removal postures.

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