Diagnostic device for force sensor and robot control device

Abstract

The diagnostic device of the force sensor diagnoses the force sensor provided in the robot. The force sensor is arranged near the installation surface where the robot is installed, and detects the force and torque applied to the robot from the outside. The diagnostic device of the force sensor includes: a calculation unit (23) that calculates the respective theoretical values of the force and torque detected by the force sensor; a determination unit (24) that determines whether the force sensor is deformed by comparing the measured values of the force and torque detected by the force sensor with the theoretical values of the force and torque; and a notification unit (25) that notifies the determination result of the determination unit (24).

Description

Technical Field

[0001] The present invention relates to a diagnostic device for a force sensor and a robot control device. Background Art

[0002] Conventionally, a force sensor has been provided on an industrial robot, and the force sensor detects an external force applied to the robot to detect contact between the robot and an object or a person (for example, refer to Patent Documents 1 and 2). In Patent Documents 1 and 2, the force sensor is disposed near the installation surface where the robot is installed.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-042906

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2018-080941 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] There are cases where the detection accuracy of the force sensor decreases for some reason. If the robot operates in a state where the detection accuracy of the force sensor has decreased, it may not be possible to accurately detect contact between the robot and an object or a person. Therefore, before the robot starts operating, it is necessary to confirm whether the detection accuracy of the force sensor meets a specified standard. However, there are various causes for the decrease in detection accuracy, and it is not easy to determine the cause.

[0009] Solutions to the Problems

[0010] One aspect of the present disclosure is a diagnostic device for a force sensor that diagnoses a force sensor provided in a robot. The force sensor is disposed near an installation surface where the robot is installed and detects a force and a torque applied to the robot from the outside. The diagnostic device for the force sensor is characterized by including: a calculation unit that calculates respective theoretical values of the force and the torque detected by the force sensor; a determination unit that determines whether the force sensor is deformed by comparing measured values of the force and the torque detected by the force sensor with the theoretical values of the force and the torque; and a notification unit that notifies a determination result of the determination unit. Brief Description of the Drawings

[0011] Figure 1 is an overall configuration diagram of a robot system according to an embodiment.

[0012] Figure 2A is a diagram showing an example of correct installation of a mounting plate.

[0013] Figure 2B This is a diagram showing an example of incorrect setting of the setting plate.

[0014] Figure 3 This is a functional block diagram of a robot control device according to an embodiment.

[0015] Figure 4 This is a diagram showing an example of the set value of the load connected to the robot.

[0016] Figure 5 This is a diagram for explaining the operation of the rotating body of the robot main body during the sensor diagnosis operation.

[0017] Figure 6 This is a diagram for explaining the operation of the first arm of the robot main body during the sensor diagnosis operation.

[0018] Figure 7 This is a diagram showing an example of the diagnostic result of the force sensor displayed by the notification unit.

[0019] Figure 8 This is a flowchart showing the diagnostic method of the force sensor executed by the robot control device.

[0020] Figure 9A This is a graph showing the time change of the rotation angles of the rotating body and the first arm during the sensor diagnosis operation.

[0021] Figure 9B This is a graph showing the time change of the force error ΔF during the sensor diagnosis operation.

[0022] Figure 9C This is a graph showing the time change of the torque error ΔM during the sensor diagnosis operation.

[0023] Figure 10 This is a diagram showing a modified example of the judgment result of the judgment unit. Detailed Embodiment

[0024] Hereinafter, a diagnostic device for a force sensor, a robot control device, and a robot system according to an embodiment will be described with reference to the accompanying drawings.

[0025] As Figure 1 shown, the robot system 100 of the present embodiment includes an industrial robot 1 and a robot control device 2 that is connected to and controls the robot 1.

[0026] The robot 1 includes a robot main body 3, a mounting plate 4 for fixing the robot main body 3 to a mounting surface S, and a force sensor 5 for detecting the force and torque applied to the robot main body 3 from the outside. For example, the robot 1 is a collaborative robot that works in the same working space as an operator, and the robot main body 3 is a six-axis vertical multi-joint robot.

[0027] The robot main body 3 has a base 6, a rotating body 7, a first arm 8, and a second arm 9. The rotating body 7 is placed on the base 6 and can rotate relative to the base 6 about a first axis J1 in the vertical direction. The base end portion of the first arm 8 is supported by the rotating body 7 and can rotate relative to the rotating body 7 about a second axis J2 in the horizontal direction. The base end portion of the second arm 9 is supported by the front end portion of the first arm 8 and can rotate relative to the first arm 8 about a third axis J3 in the horizontal direction.

[0028] A plurality of servo motors (not shown) for rotating the rotating body 7, the first arm 8, and the second arm 9 respectively, and a plurality of encoders (not shown) for detecting the rotation angles of the rotating body 7, the first arm 8, and the second arm 9 respectively are provided on the robot main body 3.

[0029] A mounting surface 10 for mounting a load 11 is provided at the front end of the second arm 9. The load 11 is, for example, an end effector such as a hand or a tool.

[0030] As Figure 2A shown, the mounting plate 4 is arranged on a horizontal or substantially horizontal mounting surface S such as the ground, and is fixed to the mounting surface S with a very large force, for example, a force of several tons, by anchor bolts 12 such as chemical anchor bolts.

[0031] The force sensor 5 is arranged between the base 6 and the mounting plate 4 and is fixed to the base 6 and the mounting plate 4. For example, the force sensor 5 has a cylindrical main body that deforms due to an external force applied to the robot main body 3, and a plurality of strain sensors fixed to the main body. The force sensor 5 is, for example, a six-axis force sensor. The force detected by the force sensor 5 includes three force components in the X-axis, Y-axis, and Z-axis directions, and the torque detected by the force sensor 5 includes three torque components about the X-axis, Y-axis, and Z-axis. The X-axis, Y-axis, and Z-axis are mutually orthogonal.

[0032] The force sensor 5 arranged near the mounting surface S is easily affected by the mounting state of the mounting plate 4 on the mounting surface S, and there is a case where the force sensor 5 is deformed due to the mounting plate 4 being incorrectly mounted on the mounting surface S.

[0033] Figure 2A An example of the correct mounting of the mounting plate 4 is shown, Figure 2B An example of the incorrect mounting of the mounting plate 4 is shown. As Figure 2AAs shown, when the installation surface S has unevenness, a spacer 13 is inserted into the gap between the installation plate 4 and the installation surface S to ensure the flatness of the installation plate 4. As Figure 2B shown, when the spacer 13 is not inserted or the spacer 13 is not properly inserted, the installation plate 4 is deformed as shown by the arrow due to the force from the anchor bolt 12, and the force sensor 5 fixed to the installation plate 4 is deformed.

[0034] As Figure 3 shown, the robot control device 2 includes a storage unit 21, a control unit 22, a calculation unit 23, a determination unit 24, and a notification unit 25.

[0035] The robot control device 2 has a sensor diagnosis function for diagnosing the force sensor 5, and the calculation unit 23, the determination unit 24, and the notification unit 25 are responsible for the sensor diagnosis function. That is, in one embodiment, the diagnostic device for the force sensor is mounted on the robot control device 2 as a part of the robot control device 2.

[0036] A sensor diagnosis program for diagnosing the force sensor 5 is stored in the storage unit 21. The robot control device 2 has a processor, and the processor executes processing according to the sensor diagnosis program to implement the functions of the control unit 22, the calculation unit 23, the determination unit 24, and the notification unit 25 described later.

[0037] The storage unit 21 has a RAM (Random Access Memory), a ROM (Read-Only Memory), and any other storage device. A set value of the load 11 connected to the robot 1 is stored in the storage unit 21. As Figure 4 shown, the set value includes, for example, the mass M of the load 11, the center of gravity position (Gx, Gy, Gz) of the load 11 based on the center position of the mounting surface 10, and the inertia Ix, Iy, Iz of the load 11 about the center of gravity G. The set value is input to the robot control device 2 by an operator, for example, and stored in the storage unit 21.

[0038] The control unit 22 controls the robot main body 3 and the force sensor 5. The control unit 22 controls the servo motor to cause the robot main body 3 to perform a sensor diagnosis operation that changes the posture of the robot main body 3. In addition, during the posture change of the robot main body 3 in the sensor diagnosis operation, the control unit 22 causes the force sensor 5 to detect force and torque. The measured values Fa and Ma of the force and torque detected by the force sensor 5 are sent from the force sensor 5 to the robot control device 2 for diagnosing the force sensor 5.

[0039] Figure 5 and Figure 6Shows the sensor diagnostic operation of the robot main body 3. In the sensor diagnostic operation, the posture of the robot main body 3 changes from the initial posture to the first posture only by the rotation of the rotating body 7 about the first axis J1 (refer to Figure 5 .), and then, changes from the first posture to the second posture only by the rotation of the first arm 8 about the second axis J2 (refer to Figure 6 .). The initial posture is the posture in which the load 11 is arranged at a position horizontally away from the first axis J1. For example, the first arm 8 and the second arm 9 are in a horizontally extended posture.

[0040] The respective rotation angle ranges of the rotating body 7 and the first arm 8 in the sensor diagnostic operation are arbitrarily set by the operator. The rotating body 7 and the first arm 8 are preferably rotated to their respective maximum rotation angles, and the respective rotation amounts of the rotating body 7 and the first arm 8 are preferably 90° or more.

[0041] For example, in the sensor diagnostic operation, the rotating body 7 rotates from 0° to 180°, and the first arm 8 rotates from 90° to 0° (refer to Figure 9A .). That is, in the initial posture, the rotation angle of the rotating body 7 is 0°, and the rotation angle of the first arm 8 is 90°. The first arm 8 extends horizontally at 90° and vertically at 0°.

[0042] The calculation unit 23 reads the set value of the load 11 from the storage unit 21, and uses the set value of the load 11 to calculate the respective theoretical values Ft, Mt of the force and torque detected by the force sensor 5 during the sensor diagnostic operation. For example, the theoretical value Ft is the root mean square of the theoretical values of the three force components in the X-axis, Y-axis, and Z-axis directions, and the theoretical value Mt is the root mean square of the theoretical values of the three torque components about the X-axis, Y-axis, and Z-axis.

[0043] When the theoretical values Ft, Mt change correspondingly according to the change of the posture of the robot main body 3, in order to calculate the theoretical values Ft, Mt, information on the posture of the robot main body 3 is required. In this case, the calculation unit 23 acquires information on the posture of the robot main body 3 at each moment during the sensor diagnostic operation. For example, the respective rotation angles of the rotating body 7, the first arm 8, and the second arm 9 are sent from the encoder to the robot control device 2 and stored in the storage unit 21 in time series. The calculation unit 23 calculates the posture of the robot main body 3 at each moment based on the rotation angles stored in the storage unit 21, and uses the set value of the load 11 and the posture of the robot main body 3 to calculate the theoretical values Ft, Mt.

[0044] As described in detail later, the determination unit 24 determines whether the set value of the load 11 is correct and whether the force sensor 5 is deformed due to incorrect setting of the setting plate 4 by comparing the measured values Fa and Ma with the theoretical values Ft and Mt. For example, the measured value Fa is the root mean square of the three force components in the X-axis, Y-axis, and Z-axis directions actually detected by the force sensor 5, and the measured value Ma is the root mean square of the three torque components about the X-axis, Y-axis, and Z-axis actually detected by the force sensor 5.

[0045] When it is determined that the set value of the load 11 is correct and the force sensor 5 is not deformed, the determination unit 24 determines that the detection accuracy of the force sensor 5 is "qualified".

[0046] On the other hand, when it is determined that the set value of the load 11 is incorrect and / or the force sensor 5 is deformed, the determination unit 24 determines that the detection accuracy of the force sensor 5 is "unqualified", and selects one mode from "Mode 1", "Mode 2", and "Mode 3" based on the reason for the unqualified.

[0047] The notification unit 25 has a display (not shown) and displays the determination result of the determination unit 24 on the display. When the determination result is "qualified", the notification unit 25 displays "qualified". When the determination result is unqualified, as Figure 7 shown, the notification unit 25 displays the mode selected by the determination unit 24 and the corresponding countermeasure method for the selected mode.

[0048] Next, a diagnostic method for the force sensor 5 executed by the robot control device 2 will be described with reference to Figure 8 For example, by executing a sensor diagnostic program based on an operator's instruction, the robot control device 2 starts the diagnostic method for the force sensor 5. The sensor diagnostic method is executed without applying force and torque to the robot main body 3 from the outside.

[0049] First, the control unit 22 obtains the measured value Fa of the force and the measured value Ma of the torque by controlling the robot main body 3 and the force sensor 5 (step S1). Specifically, the robot main body 3 performs a sensor diagnostic operation, and the rotating body 7 and the first arm 8 rotate in sequence. As a result, the posture of the robot main body 3 changes from the initial posture to the first posture, and then from the first posture to the second posture. During the rotation of the rotating body 7 and during the rotation of the first arm 8, the force and torque are detected by the force sensor 5.

[0050] Next, the calculation unit 23 calculates the theoretical values Ft and Mt of the force and torque detected by the force sensor 5 during the rotation of the rotating body 7 and during the rotation of the first arm 8 using the set value of the load 11 connected to the robot main body 3 (step S2).

[0051] Next, through the determination unit 24, the force error ΔF = |Fa - Ft|, which is the magnitude of the difference between the measured value Fa and the theoretical value Ft, and the torque error ΔM = |Ma - Mt|, which is the magnitude of the difference between the measured value Ma and the theoretical value Mt, are calculated (step S3).

[0052] The control unit 22 can also set the zero point of the force sensor 5 such that the force and torque detected by the force sensor 5 are both zero when the robot main body 3 is configured in the initial posture, and then change the posture of the robot main body 3. In this case, regardless of how the posture of the robot main body 3 changes relative to the initial posture, the theoretical values Ft and Mt calculated by the calculation unit 23 are always zero.

[0053] Figure 9A Shows the time variation of the rotation angles of the rotating body 7 and the first arm 8 during the sensor diagnostic operation, Figure 9B Shows the time variation of the measured value Fa and the theoretical value Ft of the force during the sensor diagnostic operation, that is, shows the time variation of the force error ΔF, Figure 9C Shows the time variation of the measured value Ma and the theoretical value Mt of the torque during the sensor diagnostic operation, that is, shows the time variation of the torque error ΔM.

[0054] In Figure 9B and Figure 9C the zero point of the force sensor 5 is set such that the force error ΔF and the torque error ΔM in the initial posture are both zero. When the set value of the load 11 is correct and the force sensor 5 is not deformed due to the incorrect setting of the setting plate 4, the force error ΔF and the torque error ΔM are always zero or approximately zero respectively.

[0055] On the other hand, when the set value of the load 11 is incorrect due to the operator inputting incorrect values for the mass M or the center of gravity position (Gx, Gy, Gz), etc., non-zero force error ΔF and torque error ΔM are detected even though no force and torque are externally applied to the robot main body 3. In this case, the force error ΔF and the torque error ΔM change with the change of the posture of the robot main body 3. In particular, the torque error ΔM changes significantly with the rotation of the rotating body 7.

[0056] In addition, when the force sensor 5 is deformed due to the incorrect setting of the setting plate 4, non-zero force error ΔF and torque error ΔM are detected even though no force is externally applied to the robot main body 3. In this case, the force error ΔF and the torque error ΔM change with the change of the posture of the robot main body 3. In particular, the force error ΔF changes significantly with the rotation of the first arm 8.

[0057] Next, the torque error ΔM is compared with a specified first threshold Th1 by the determination unit 24 (step S4), and it is determined whether the set value of the load 11 is correct. Specifically, when the torque error ΔM is equal to or less than the first threshold Th1 throughout the period of the attitude change of the robot main body 3, it is determined that the set value of the load 11 is correct. On the other hand, as Figure 9C shown, when there is a period during which the torque error ΔM is greater than the first threshold Th1 during the attitude change of the robot main body 3, it is determined that the set value of the load 11 is incorrect.

[0058] Next, the force error ΔF is compared with a specified second threshold Th2 by the determination unit 24 (step S5 or S6), and it is determined whether the force sensor 5 is deformed due to a mis-setting of the setting plate 4. Specifically, when the force error ΔF is equal to or less than the second threshold Th2 throughout the period of the attitude change of the robot main body 3, it is determined that the force sensor 5 is not deformed. On the other hand, as Figure 9B shown, when there is a period during which the force error ΔF is greater than the second threshold Th2 during the attitude change of the robot main body 3, it is determined that the force sensor 5 is deformed.

[0059] When it is determined that the set value of the load 11 is correct and the force sensor 5 is not deformed (Yes in step S4 and Yes in step S5), the determination unit 24 determines that the detection accuracy of the force sensor 5 is "qualified". Next, the diagnosis result is notified as "qualified" by the notification unit 25 (step S7), and the diagnosis method of the force sensor 5 ends.

[0060] When it is determined that the set value of the load 11 is correct (Yes in step S4) and the force sensor 5 is deformed (No in step S5), the determination unit 24 determines that the detection accuracy of the force sensor 5 is "unqualified". In this case, the reason for "unqualified" is the deformation of the force sensor 5 caused by the mis-setting of the setting plate 4. Therefore, the determination unit 24 selects "Mode 3" corresponding to the mis-setting of the setting plate 4, and the notification unit 25 notifies the diagnosis result as "Mode 3" (step S8). At this time, as a countermeasure, the confirmation of the setting state of the setting plate 4 is notified together with the diagnosis result.

[0061] When it is determined that the set value of the load 11 is incorrect (No in step S4) and the force sensor 5 is not deformed (Yes in step S6), the determination unit 24 determines that the detection accuracy of the force sensor 5 is "unqualified". In this case, the reason for "unqualified" is the incorrect set value of the load 11. Therefore, the determination unit 24 selects "Mode 2" corresponding to the incorrect set value of the load 11, and the notification unit 25 notifies the diagnosis result as "Mode 2" (step S9). At this time, as a countermeasure, the confirmation of the set value of the load 11 is notified together with the diagnosis result.

[0062] When it is determined that the set value of the load 11 is incorrect (No in step S4) and the force sensor 5 is deformed (No in step S4 and No in step S6), the determination unit 24 determines that the detection accuracy of the force sensor 5 is "unqualified". In this case, the reasons for "unqualified" are the incorrect setting of the setting plate 4 and the incorrect set value of the load 11. Therefore, the determination unit 24 selects "Mode 1" corresponding to the incorrect setting of the setting plate 4 and the incorrect set value of the load 11, and the notification unit 25 notifies that the diagnosis result is "Mode 1" (step S10). At this time, as a countermeasure, the confirmation of the set value of the load 11 and the re-diagnosis are notified together with the diagnosis result.

[0063] When the diagnosis result is "unqualified", the operator corrects the set value of the load 11 or the setting state of the setting plate 4 according to the countermeasure notified by the notification unit 25, and then executes the diagnosis method of the force sensor 5 again (Yes in step S11). The operator repeats the correction of the set value of the load 11 or the correction of the setting state of the setting plate 4, and the re-execution of the diagnosis until the diagnosis result becomes "qualified".

[0064] In this way, the deformation of the force sensor 5 caused by the incorrect setting of the setting plate 4 and the incorrect setting of the set value of the load 11 may cause the detection accuracy of the force sensor 5 to decrease. When the robot main body 3 operates in a state where the detection accuracy of the force sensor 5 has decreased, for example, a situation may occur where although the robot main body 3 is not in contact with an object or a person, contact is detected and the robot main body 3 stops. Therefore, in order for the robot 1 to operate normally, it is necessary to confirm that the detection accuracy of the force sensor 5 meets the required standard before the operation of the robot main body 3 starts. However, for example, it is not easy for the operator to determine the cause of the decrease in detection accuracy only based on the force error ΔF and the torque error ΔM.

[0065] According to the present embodiment, during the sensor diagnosis operation, while changing the posture of the robot main body 3, the force and torque are detected by the force sensor 5, and the force error ΔF and the torque error ΔM are measured. When the set value of the load 11 is incorrect, especially the torque error ΔM becomes larger; when the force sensor 5 is deformed, especially the force error ΔF becomes larger. Therefore, it is possible to judge whether the set value of the load is correct and whether the force sensor 5 is deformed based on the torque error ΔM and the force error ΔF. In addition, the cause of the decrease in the detection accuracy of the force sensor 5 can be determined by a simple operation of the robot main body 3 and simple calculations performed by the robot control device 2.

[0066] In addition, when the set value of the load 11 is incorrect, the torque error ΔM during the rotation of the rotating body 7 increases, and when the force sensor 5 is deformed, the force error ΔF during the rotation of the first arm 8 increases. Therefore, by separately rotating the rotating body 7 and the first arm 8, it is possible to distinguish between the mis-setting of the set value of the load 11 and the deformation of the force sensor 5.

[0067] In addition, according to the present embodiment, the determined cause and the corresponding countermeasure are notified to the operator together. Thereby, the operator can be reminded to take appropriate countermeasures. By appropriately responding according to the notified countermeasure, the operator can reliably complete the adjustment of the detection accuracy of the force sensor 5 in a short time.

[0068] In the above embodiment, the thresholds Th1 and Th2 of the errors ΔM and ΔF can also be changed according to the amount of change in the posture of the robot main body 3 during the sensor diagnosis operation, that is, according to the rotation amounts of the rotating body 7 and the first arm 8.

[0069] For example, the rotation ranges of the rotating body 7 and the first arm 8 may be limited due to the presence of structures around the robot main body 3. The larger the rotation amounts of the rotating body 7 and the first arm 8, the larger the errors ΔM and ΔF. Therefore, when the thresholds Th1 and Th2 are constant regardless of the rotation amount, there is a situation where it is impossible to accurately determine whether the set value of the load 11 is correct and whether the force sensor 5 is deformed.

[0070] By increasing the thresholds Th1 and Th2 as the rotation amount increases, it is possible to accurately determine whether the set value of the load 11 is correct and whether the force sensor 5 is deformed. For example, when the rotation amount is less than 90°, the thresholds Th1 and Th2 can be made proportional to the rotation amount in such a way that the thresholds Th1 and Th2 decrease as the rotation amount decreases.

[0071] In the above embodiment, the determination unit 24 determines the detection accuracy of the force sensor 5 in two grades of "qualified" and "unqualified", but instead, it can also be determined in three or more grades. For example, as Figure 10 shown, the determination unit 24 can also make a determination in four grades of "excellent", "good", "slightly poor", and "poor". In this example, in the case of "slightly poor" or "poor", the notification unit 25 notifies the mode and the countermeasure.

[0072] According to this configuration, the operator can more specifically identify the degree of the detection accuracy of the force sensor 5 based on the more detailed determination result.

[0073] In the above-described embodiment, the force error ΔF and the moment error ΔM are continuously detected during the attitude change of the robot main body 3. Instead, the force error ΔF and the moment error ΔM may be detected only when the attitude of the robot main body 3 is a specified attitude.

[0074] For example, the force error ΔF and the moment error ΔM may be detected at two moments when the attitude of the robot main body 3 is the first attitude and the second attitude, and the difference between the errors at the two moments may be used to perform the determination in steps S4 to S6.

[0075] In the above-described embodiment, the determination unit 24 determines both whether the set value of the load 11 is correct and whether the force sensor 5 is deformed. Instead, it may be determined only whether the force sensor 5 is deformed.

[0076] Even if the notified determination result is only whether the force sensor 5 is deformed, it is possible to assist the operator in determining the cause of the decrease in the detection accuracy of the force sensor 5 and to prompt the operator to take appropriate countermeasures.

[0077] In the above-described embodiment, the diagnostic device for the force sensor is implemented as a part of the function of the robot control device 2. Instead, the diagnostic device for the force sensor and the robot control device 2 may be separately provided. For example, the diagnostic device for the force sensor having the calculation unit 23, the determination unit 24, and the notification unit 25 may be arranged outside the robot control device 2 and connected to the robot control device 2.

[0078] In the above-described embodiment, the robot 1 is a six-axis vertical multi-joint robot, but the robot 1 may also be a vertical multi-joint robot having an axis number other than six or a robot having other joints.

[0079] Explanation of reference numerals:

[0080] 1 Robot

[0081] 2 Robot control device

[0082] 5 Force sensor

[0083] 11 Load

[0084] 21 Storage unit

[0085] 22 Control unit

[0086] 23 Calculation unit

[0087] 24 Judgment unit

[0088] 25 Notification unit

[0089] S Setting surface.

Claims

1. A diagnostic device for a force sensor that diagnoses a force sensor provided in a robot. The force sensor is disposed near a setting surface where the robot is set, and detects a force and a torque applied to the robot from the outside. The diagnostic device for the force sensor is characterized by comprising: a calculation unit that calculates respective theoretical values of the force and the torque detected by the force sensor; a determination unit that determines whether the force sensor is deformed by comparing measured values of the force and the torque detected by the force sensor with the respective theoretical values of the force and the torque; and a notification unit that notifies a determination result of the determination unit, wherein the determination unit determines that the force sensor is not deformed when a torque error is equal to or less than a prescribed first threshold value and a force error is equal to or less than a prescribed second threshold value. The torque error is a magnitude of a difference between the measured value of the torque and the theoretical value of the torque, and the force error is a magnitude of a difference between the measured value of the force and the theoretical value of the force. When the torque error is equal to or less than the prescribed first threshold value and the force error is greater than the prescribed second threshold value, it is determined that the force sensor is deformed.

2. The diagnostic device for a force sensor according to claim 1, wherein the calculation unit calculates the respective theoretical values of the force and the torque using a set value of a load connected to the robot, and the determination unit further determines whether the set value of the load is correct by comparing the measured values of the force and the torque with the respective theoretical values of the force and the torque.

3. The diagnostic device for a force sensor according to claim 2, wherein the determination unit determines whether the set value of the load is correct based on the torque error, which is a magnitude of a difference between the measured value of the torque and the theoretical value of the torque.

4. The diagnostic device for a force sensor according to claim 3, wherein the determination unit determines that the set value of the load is correct when the torque error is equal to or less than the prescribed first threshold value, and determines that the set value of the load is incorrect when the torque error is greater than the prescribed first threshold value.

5. The diagnostic device for a force sensor according to claim 1, wherein the determination unit determines whether the force sensor is deformed based on the torque error and the force error when the posture of the robot changes.

6. The diagnostic device for a force sensor according to claim 5, wherein the determination unit changes the prescribed second threshold value according to a change amount of the posture of the robot.

7. The diagnostic device for a force sensor according to claim 4, wherein the determination unit determines whether the set value of the load is correct based on the torque error when the posture of the robot changes.

8. The diagnostic device for a force sensor according to claim 7, wherein the determination unit changes the prescribed first threshold value according to a change amount of the posture of the robot.

9. The diagnostic device for a force sensor according to any one of claims 1 to 8, wherein The calculation unit acquires information on the posture of the robot, and calculates the theoretical value of the force and the theoretical value of the torque based on the acquired posture.

10. A robot control device having a function of diagnosing a force sensor provided in a robot, the force sensor being disposed near a setting surface on which the robot is set, and detecting a force and a torque applied to the robot from the outside, The robot control device is characterized by including: A control unit that controls the robot; A calculation unit that calculates the respective theoretical values of the force and the torque detected by the force sensor; A determination unit that determines whether the force sensor is deformed by comparing the measured values of the force and the torque detected by the force sensor with the theoretical values of the force and the torque; And A notification unit that notifies the determination result of the determination unit, When the torque error is equal to or less than a prescribed first threshold value and the force error is equal to or less than a prescribed second threshold value, the determination unit determines that the force sensor is not deformed. The torque error is the magnitude of the difference between the measured value of the torque and the theoretical value of the torque, and the force error is the magnitude of the difference between the measured value of the force and the theoretical value of the force. When the torque error is equal to or less than a prescribed first threshold value and the force error is greater than a prescribed second threshold value, it is determined that the force sensor is deformed.

11. A robot control device having a function of diagnosing a force sensor provided in a robot, the force sensor being disposed near a setting surface on which the robot is set, and detecting a force and a torque applied to the robot from the outside, The robot control device is characterized by including: A control unit that controls the robot; A calculation unit that calculates the respective theoretical values of the force and the torque detected by the force sensor; A determination unit that determines whether the force sensor is deformed by comparing the measured values of the force and the torque detected by the force sensor with the theoretical values of the force and the torque; A notification unit that notifies the determination result of the determination unit; And A storage unit that stores set values of loads connected to the robot, The calculation unit calculates the respective theoretical values of the force and the torque using the set values of the loads stored in the storage unit, The determination unit further determines whether the set values of the loads are correct by comparing the measured values of the force and the torque with the theoretical values of the force and the torque.

12. The robot control device according to claim 11, wherein The control unit causes the robot to perform a sensor diagnosis operation for changing the posture of the robot, and causes the force sensor to perform detection of the force and the torque during the posture change of the robot in the sensor diagnosis operation.

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