Workpiece mass estimation device

Abstract

The purpose of the present invention is to easily confirm whether or not a repetitive operation is normally processed. A workpiece mass estimation device is a device for a machine. The machine includes a motor that drives the workpiece placement portion, and a sensor that detects a state of the motor. The workpiece quality estimation apparatus includes a recognition unit, a storage unit, an estimation unit, and a display. The recognition unit recognizes a value of a physical parameter of a driven body driven by the output of the motor on the basis of the state of the motor detected by the sensor, and continuously updates the recognized value by repeated calculations. The storage unit continuously stores the continuously updated value of the physical parameter. The estimation unit estimates the quality of the workpiece on the basis of a final value of the continuously updated values of the physical parameters. The display displays a graph indicating the transition of the value of the physical parameter on the basis of the data stored in the storage unit, and displays the quality estimated by the estimation unit.

Description

Technical Field

[0001] The present disclosure relates to a workpiece mass estimation device that estimates the mass of a workpiece placed on various machines such as machine tools. Background Art

[0002] In machines such as machine tools, there are machines equipped with a workpiece placement unit, a motor, a sensor, and a motor control unit. A workpiece is placed on the workpiece placement unit. The motor drives the workpiece placement unit. The sensor detects the state of the motor. The state of the motor includes, for example, the current value and rotation speed of the motor. The motor control unit performs feedback control on the motor based on the detected state of the motor.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2015-55923 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The total mass of the driven bodies driven by the motor varies according to the mass of the workpiece placed on the workpiece placement unit. Therefore, the inertia of the driven bodies also varies according to the mass of the workpiece. According to this change in inertia, the acceleration and deceleration of the driven bodies by the motor change. Excessive acceleration and deceleration can impose excessive loads on the machine and cause mechanical failures. On the other hand, insufficient acceleration and deceleration can deteriorate the working efficiency of the machine. Therefore, it is necessary to adjust the acceleration and deceleration of the driven bodies by the motor to an optimal value. Thus, in the machine, there is a machine that adjusts the acceleration and deceleration of the driven bodies by the motor to an optimal value according to the mass of the workpiece input by the operator.

[0008] According to such a technique, the acceleration and deceleration of the driven bodies can be adjusted, but the operator needs to manually input the mass of the workpiece each time. Therefore, a method for automatically estimating the mass of the workpiece is proposed as follows. First, a specified operation instruction is transmitted to the motor control unit of the machine to drive the motor to drive the driven bodies. Based on the current feedback value and rotation speed feedback value detected by the sensor, etc., the inertia of the driven bodies at this time is identified. By subtracting the inertia due to non-workpieces from the identified inertia of the driven bodies, the inertia of the workpiece is calculated, and the mass of the workpiece is estimated.

[0009] However, the present inventors have focused on the following points: the following problems may occur in such a structure.

[0010] In the process of estimating the quality of a workpiece, the values of physical parameters are sometimes continuously updated successively through iterative calculations such as the steepest descent method. The physical parameters include the inertia of the driven body and the parameters for calculating the inertia. The estimated quality of the workpiece is calculated based on the final value among the updated values of the physical parameters. Therefore, the estimated quality of the workpiece depends on this final value.

[0011] When the iterative calculation is processed normally, there is no problem. However, when the iterative calculation is not processed normally, the values of the physical parameters do not converge within the limited time, and the final value will not be the correct value. As a result, the estimated quality of the workpiece deviates from the quality of the original workpiece.

[0012] The present disclosure has been completed in view of the above circumstances, and its object is to easily confirm whether the iterative calculation is processed normally.

[0013] Solution to the Problem

[0014] The workpiece quality estimation device of the present disclosure is a workpiece quality estimation device for mechanically estimating the quality of a workpiece. The machine has a workpiece placement unit for placing the workpiece, a motor for driving the workpiece placement unit, a sensor for detecting the state of the motor, and a motor control unit for controlling the motor based on the detected state of the motor. The workpiece quality estimation device includes:

[0015] An identification unit that identifies the values of the physical parameters of the driven body driven by the output of the motor based on the detected state of the motor, and continuously updates the identified values through iterative calculations;

[0016] A storage unit that continuously stores the continuously updated values of the physical parameters;

[0017] An estimation unit that estimates the quality of the workpiece based on the final value of the continuously updated values of the physical parameters; and

[0018] A display that displays a graph showing the change in the values of the physical parameters based on the data stored in the storage unit, and displays the quality estimated by the estimation unit. Description of the Drawings

[0019] Figure 1 is a schematic diagram showing the workpiece quality estimation device and the machine tool of the first embodiment.

[0020] Figure 2 is a flowchart showing the process of estimating the quality of the workpiece.

[0021] Figure 3 is a diagram showing the normal mode displayed on the display.

[0022] Figure 4 This is a diagram showing the first abnormal mode displayed on the display.

[0023] Figure 5 This is a diagram showing the second abnormal mode displayed on the display.

[0024] Figure 6 This is a diagram showing the third abnormal mode displayed on the display.

[0025] Figure 7 This is a diagram showing the fourth abnormal mode displayed on the display. Detailed implementation mode

[0026] [First implementation mode]

[0027] As Figure 1 shown, the workpiece quality estimation device 100 of this implementation mode is set for the machine tool 200. The machine tool 200 includes a motor control unit 50, a sensor 60, a motor 70, a transmission mechanism 80, and a workpiece placement unit 90.

[0028] The workpiece placement unit 90 is arranged to be movable in the rotational direction or the linear direction. A workpiece W is placed on the workpiece placement unit 90. The motor 70 has a rotor 78 and a stator 76 that rotates the rotor 78. Hereinafter, the output from the stator 76 to the rotor 78 will be referred to as "motor output Mo". The transmission mechanism 80 transmits the motor output Mo from the rotor 78 to the workpiece placement unit 90. The transmission mechanism 80 may include a speed reducer such as a gear.

[0029] Hereinafter, the part in the machine tool 200 that transmits the motor output Mo to the workpiece placement unit 90 will be referred to as the "transmission system". The transmission system includes the transmission mechanism 80 and its periphery. In addition, hereinafter, the group of components driven by the motor output Mo will be referred to as the "driven body Dv". The driven body Dv includes the rotor 78, the transmission mechanism 80, the workpiece placement unit 90, and the workpiece W. In addition, hereinafter, the components excluding the workpiece W from the driven body Dv will be referred to as the "general driven body".

[0030] The sensor 60 detects motor information Mi indicating the state of the motor 70. The motor information Mi includes the current value of the motor 70 and the rotational speed of the rotor 78. The motor control unit 50 performs feedback control on the motor 70 based on the motor information Mi detected by the sensor 60.

[0031] Next, the workpiece quality estimation device 100 will be described. The workpiece quality estimation device 100 is a device for estimating the quality of the workpiece W. Hereinafter, the estimation of the quality of the workpiece W will be simply referred to as "quality estimation", and the quality estimated by this quality estimation will be simply referred to as "estimated quality".

[0032] The workpiece quality estimation device 100 includes an identification unit 10, a storage unit 20, an estimation unit 30, and a display 40. The identification unit 10, the storage unit 20, and the estimation unit 30 are, for example, configured with the same computer as the main body. The display 40 is, for example, configured with the above-mentioned computer and display as the main body. The computer has, for example, a CPU, a ROM, a RAM, a memory, etc. In addition, in Figure 1 Although the workpiece quality estimation device 100 and the machine tool 200 are shown independently of each other, the workpiece quality estimation device 100 may also be incorporated into the machine tool 200.

[0033] The identification unit 10 identifies the physical parameters of the driven body Dv based on the motor information Mi detected by the sensor 60, and continuously updates the identified values successively through iterative calculations such as the steepest descent method. The physical parameters include the inertia of the driven body Dv, the viscous friction coefficient in the transmission system, the Coulomb friction coefficient in the transmission system, and the spring constant in the transmission system. Hereinafter, the viscous friction coefficient in the transmission system will be simply referred to as "viscous friction coefficient", the Coulomb friction coefficient in the transmission system will be simply referred to as "Coulomb friction", and the spring constant in the transmission system will be simply referred to as "spring constant". The inertia of the driven body Dv is calculated considering the viscous friction coefficient, the Coulomb friction coefficient, and the spring constant.

[0034] The storage unit 20 continuously stores the values of the physical parameters continuously updated by the identification unit 10.

[0035] When the final value of the physical parameter values continuously updated by the identification unit 10 is within a specified range, the estimation unit 30 performs quality estimation based on the final value. Specifically, the estimation unit 30 calculates the inertia of the workpiece W by subtracting the inertia of a general driven body from the final value of the inertia of the driven body Dv identified by the identification unit 10. In addition, for example, the inertia of the general driven body is calculated based on the mass of the general driven body input in advance. The estimation unit 30 performs quality estimation based on the calculated inertia of the workpiece W. On the other hand, the estimation unit 30 does not perform quality estimation when the final value of the physical parameter values continuously updated by the identification unit 10 falls outside the specified range.

[0036] As Figures 3 to 7 shown, the display 40 displays a graph 41 representing the change in the values of the physical parameters based on the data stored in the storage unit 20. The graph 41 includes an inertia graph 41a representing the change in inertia, a viscous friction coefficient graph 41b representing the change in the viscous friction coefficient, a Coulomb friction coefficient graph 42c representing the change in the Coulomb friction coefficient, and a spring constant graph 42d representing the change in the spring constant.

[0037] When the quality estimation is performed by the estimation unit 30, the display 40 is as Figure 3displays the graph 41 as shown and displays the quality information 42 indicating the estimated quality. On the other hand, in the case where the quality estimation is not performed, that is, when the final value of the physical parameter is out of the specified range, the display 40 does not display the quality information 42 as shown in Figures 4 to 7 and instead displays an alarm 42A such as "ERR". That is, the display 40 displays the graph 41 and displays the alarm 42A.

[0038] As shown in Figures 3 to 7 , the display 40 displays the graph 41 and displays the switching unit 43, the operation mode selection unit 44, the drive amount selection unit 45, the status information 46, the date and time information 47, and the temperature information 48.

[0039] The switching unit 43 is a part for performing operations to switch the execution and suspension of the quality estimation. The switching unit 43 also serves as a reset unit for initializing the estimated quality. The switching unit 43 is configured such that the operator can select either "SET" or "RESET". If "SET" is selected, the execution of the quality estimation is selected. On the other hand, if "RESET" is selected, the execution of the quality estimation is suspended and the estimated quality is initialized. In addition, when "SET" is selected and an error such as the final value of the physical parameter being out of the specified range occurs, as shown in Figures 4 to 7 , the selection automatically returns to "RESET".

[0040] The operation mode selection unit 44 is a part for selecting the operation conditions of the driven body Dv in the quality estimation. The drive amount selection unit 45 is a part for selecting the drive amount of the driven body Dv in the quality estimation.

[0041] The status information 46 is information indicating whether the quality estimation has been completed normally. That is, when the quality estimation is completed normally, as shown in Figure 3 , the meaning of the completion of the quality estimation such as "Adjustment completed" is displayed as the status information 46. On the other hand, when the quality estimation is not completed normally, as shown in Figures 4 to 7 , the meaning of the non-completion of the quality estimation such as "Adjustment failed" is displayed as the status information 46.

[0042] The date and time information 47 is information indicating the date and time (year, month, day, time, etc.) when the quality estimation is completed. The temperature information 48 is information that represents the temperature of a specified part of the motor 70 in real time. This specified part is the part of the motor 70 where the temperature affects the quality estimation.

[0043] Next, referring to Figure 2The process of quality estimation performed by the workpiece quality estimation device 100 will be described. In addition, "S" shown below is an abbreviation for "step". First, in S1, it is determined whether quality estimation is being performed. If a negative determination N (no) is made, the determination in S1 is repeated. On the other hand, if an affirmative determination Y (yes) is made in S1, the process proceeds to the next S2.

[0044] In S2, the identification unit 10 acquires motor information Mi from the motor control unit 50.

[0045] In the next S3, the identification unit 10 identifies the value of the physical parameter based on the motor information Mi. In the next S4, the storage unit 20 stores the identified parameter information. Then, in S5, it is determined whether the duration of the estimation process has reached the limit time. If a negative determination N is made, the process returns to S3. Thus, the iterative calculation of the identification unit 10 continues. On the other hand, if an affirmative determination Y is made in S5, the process proceeds to the next S6.

[0046] In S6, it is determined whether the final value of the identified physical parameter is within a preset specified range. If an affirmative determination Y is made, the process proceeds to S8. In S8, the estimation unit 30 estimates the quality of the workpiece W based on the final value of the identified physical parameter. In the next S9, the display 40 displays the graph 41 based on the data stored in the storage unit 20, and displays the estimated quality estimated by the estimation unit 30 as the quality information 42.

[0047] On the other hand, if a negative determination N is made in the previous S6, that is, if the final value of the identified physical parameter is not within the preset specified range, the process proceeds to S9. In this S9, the display 40 displays the graph 41 based on the data stored in the storage unit 20, and displays the alarm 42A.

[0048] Next, refer to Figures 3 to 7 to describe the display mode displayed on the display 40.

[0049] Figure 3 The normal mode Np shown indicates the case where the iterative calculation is processed normally. In this normal mode Np, all physical parameters converge. Therefore, in each of the inertia graph 41a, viscous friction coefficient graph 41b, Coulomb friction coefficient graph 41c, and spring constant graph 41d, the behavior of the convergence of the values of the physical parameters appears.

[0050] In Figure 4In the first abnormal mode Ap1 shown, in all physical parameters, the iterative calculation is not processed normally. Therefore, in each of the inertia graph 411, the viscous friction coefficient graph 412, the Coulomb friction coefficient graph 413, and the spring constant graph 414, a behavior of value divergence occurs.

[0051] In Figure 5 In the second abnormal mode Ap2 shown, due to the unstable fixation of the workpiece W or unstable disturbances, a fluctuating waveform appears in the inertia graph 411.

[0052] In Figure 6 In the third abnormal mode Ap3 shown, due to the wear deterioration of the sliding components in the transmission system, a protruding waveform appears in the Coulomb friction coefficient graph 41c.

[0053] In Figure 7 In the fourth abnormal mode Ap4 shown, since the components in the transmission system change from elastic deformation to plastic deformation, the spring constant changes. As a result, an irregularly divergent waveform appears in the spring constant graph 41d.

[0054] Based on the above, the operator can determine whether the iterative calculation is processed normally according to the graph 41. Furthermore, in the case where the iterative calculation is not processed normally, the cause can be determined according to the waveform appearing in the graph 41. That is to say, the operator can infer the cause of the mass estimation failure by determining which shape the behavior appearing in the graph 41 is similar to Figures 4 to 7 to speculate the cause of the mass estimation failure.

[0055] Next, the structure and effects of this embodiment will be summarized.

[0056] The display 40 displays the graph 41 and the quality information 42. Therefore, the operator can confirm whether the iterative calculation is processed normally according to the graph 41, and confirm the estimated quality according to the quality information 42. And in the case where the iterative calculation is not processed normally, the cause can be determined according to the waveform appearing in the graph 41. Thus, it is easy for the operator to then perform appropriate processing.

[0057] Specifically, the graph 41 includes an inertia graph 41a, a viscous friction coefficient graph 41b, a Coulomb friction coefficient graph 41c, and a spring constant graph 41d. Moreover, in the case where the iterative calculation is not processed normally, the above-mentioned Figures 4 to 7 shown behavior will occur in these graphs 41a - 41d. Therefore, the operator can infer the cause of the mass estimation failure by determining which shape these behaviors are similar to.

[0058] The display 40 displays the graph 41 and the display switching unit 43. Therefore, the operator can confirm the trend of the iterative calculation etc. based on the graph 41, and switch the execution and suspension of the quality estimation through the switching unit 43.

[0059] The display 40 displays the graph 41 and the date and time information 47. Therefore, in cases such as when the iterative calculation is not processed normally, the operator can confirm the date and time when the quality estimation is completed based on the date and time information 47, and confirm the cause of the quality estimation failure based on the graph 41.

[0060] The display 40 displays the graph 41 and displays the temperature information 48 in real time. Therefore, in cases such as when the iterative calculation is not processed normally, the operator can confirm the temperature of the motor 70 based on the temperature information 48, and confirm the cause of the quality estimation failure based on the graph 41.

[0061] The display 40 displays the graph 41 and the operation mode selection unit 44. Therefore, in cases such as when the iterative calculation is not processed normally, the operator can confirm the cause of the quality estimation failure based on the graph 41, and change the operation conditions of the driven body Dv through the operation mode selection unit 44.

[0062] The display 40 displays the graph 41 and the drive amount selection unit 45. Therefore, in cases such as when the iterative calculation is not processed normally, the operator can confirm the cause of the quality estimation failure based on the graph 41, and change the drive amount of the driven body Dv through the drive amount selection unit 45.

[0063] When the quality estimation is not completed normally, the display 40 displays the graph 41 and displays the meaning indicating that the quality estimation is not completed as the status information 46. Therefore, the operator can quickly identify the non-completion of the quality estimation based on the status information 46, and can confirm the cause of the quality estimation failure based on the graph 41.

[0064] The switching unit 43 also serves as a reset unit for initializing the estimated quality. That is, the display displays the graph 41 and the reset unit. Therefore, the operator can confirm the trend of the iterative calculation etc. based on the graph 41, and reset the estimated quality by the reset unit as needed.

[0065] When the identified physical parameter deviates from the specified range, the display 40 displays the graph 41 and the alarm 42A. Therefore, the operator can quickly identify the failure of the quality estimation based on the alarm 42A, and can confirm the cause of the failure based on the graph 41.

[0066] [Other Embodiments]

[0067] The above-described embodiments can be changed, for example, as follows. The workpiece quality estimation device 100 may be provided for a machine other than the machine tool 200. Regarding the graph 41, a part of the above four graphs 41a to 41d may be omitted, or additional graphs may be added. The inertia graph 41a may represent the change in the inertia of the workpiece W instead of the change in the inertia of the driven body Db. Regarding each of the information 42A, 43 to 48 displayed together with the graph 41 other than the quality information 42, a part of it may be omitted, or additional information may be added. The switching unit 43, the operation mode selection unit 44, the drive amount selection unit 45, etc. may also be displays other than those shown as Figures 3 to 7 shown.

[0068] According to the above embodiments, the workpiece quality estimation device (100) described in Addenda 1 to 9 shown below can be realized.

[0069] [Addendum 1]

[0070] A workpiece quality estimation device (100) is a workpiece quality estimation device (100) for estimating the quality of a workpiece (W) for a machine (200). The machine (200) has a workpiece placement part (90) for placing the workpiece (W), a motor (70) for driving the workpiece placement part (90), a sensor (60) for detecting the state of the motor (70), and a motor (70) controller for controlling the motor (70) based on the detected state of the motor (70). The workpiece quality estimation device (100) includes:

[0071] An identification unit (10) that identifies the value of the physical parameter of the driven body (Dv) driven by the output of the motor (70) based on the detected state of the motor (70), and continuously updates the identified value through iterative calculation;

[0072] A storage unit (20) that continuously stores the value of the physical parameter that is continuously updated;

[0073] An estimation unit (30) that estimates the quality of the workpiece (W) based on the final value of the continuously updated value of the physical parameter; and

[0074] A display (40) that displays a graph (41) showing the change in the value of the physical parameter based on the data stored in the storage unit (20), and displays the quality (42) estimated by the estimation unit (30).

[0075] [Addendum 2]

[0076] The workpiece quality estimation device (100) according to Addendum 1, wherein

[0077] The display (40) displays the graph (41) and also displays a switching section (43) for performing and aborting operations for switching the estimation of the quality.

[0078] [Supplementary Note 3]

[0079] The workpiece quality estimation device (100) according to Supplementary Note 1 or 2, wherein

[0080] The display (40) displays the graph (41) and also displays the date and time (47) when the estimation of the quality is completed.

[0081] [Supplementary Note 4]

[0082] The workpiece quality estimation device (100) according to any one of Supplementary Notes 1 to 3, wherein

[0083] The display (40) displays the graph (41) and also displays the temperature (48) of the motor (70) in real time.

[0084] [Supplementary Note 5]

[0085] The workpiece quality estimation device (100) according to any one of Supplementary Notes 1 to 4, wherein

[0086] The display (40) displays the graph (41) and also displays an operation mode selection section (44) for selecting the operation conditions of the driven body (Dv).

[0087] [Supplementary Note 6]

[0088] The workpiece quality estimation device (100) according to any one of Supplementary Notes 1 to 5, wherein

[0089] The display (40) displays the graph (41) and, in the case where the estimation of the quality of the workpiece (W) is not normally completed, displays the meaning (46) that the estimation of the quality is not completed.

[0090] [Supplementary Note 7]

[0091] The workpiece quality estimation device (100) according to any one of Supplementary Notes 1 to 6, wherein

[0092] The display (40) displays the graph (41) and also displays a reset section (43) for initializing the estimated quality.

[0093] [Supplementary Note 8]

[0094] The workpiece quality estimation device (100) according to any one of Supplementary Notes 1 to 7, wherein

[0095] When the identified physical parameter deviates from the specified range, the display (40) displays the graph (41) and an alarm (42A).

[0096] [Appendix 9]

[0097] The workpiece quality estimation device (100) according to any one of Appendices 1 to 8, wherein

[0098] The graph (41) includes an inertia graph (41a), a viscous friction coefficient graph (4b1), a Coulomb friction coefficient graph (41c), and a spring constant graph (41d),

[0099] wherein the inertia graph (41a) represents the change in the inertia of the driven body (Dv),

[0100] The viscous friction coefficient graph (4b1) represents the change in the viscous friction coefficient in the transmission system that transmits the output of the motor (70) to the workpiece placement unit (90),

[0101] The Coulomb friction coefficient graph (41c) represents the change in the Coulomb friction coefficient in the transmission system,

[0102] The spring constant graph (41d) represents the change in the spring constant in the transmission system.

[0103] The workpiece quality estimation device (100) according to Appendices 1 to 9 above can easily confirm whether the iterative calculation is being processed normally.

[0104] The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. without departing from the gist of the present disclosure, or without departing from the spirit of the present disclosure derived from the content described in the claims and its equivalents. In addition, these embodiments can also be combined and implemented. For example, in the above-described embodiments, the order of each action and the order of each process are shown as an example and are not limited to these orders. In addition, the same applies to the cases where numerical values or mathematical formulas are used in the description of the above-described embodiments.

[0105] Explanation of reference numerals

[0106] 10: Identification unit; 20: Storage unit; 30: Estimation unit; 40: Display; 41: Chart; 41a: Inertia chart; 41b: Viscous friction coefficient chart; 41c: Coulomb friction coefficient chart; 41d: Spring constant chart; 42: Mass; 42A: Alarm; 43: Switching unit; 44: Operating mode selection unit; 46: Status information; 47: Date and time information; 48: Temperature information; 50: Motor control unit; 60: Sensor; 70: Motor; 90: Workpiece placement unit; 100: Workpiece mass estimation device; 200: Machine tool (machine); W: Workpiece.

Claims

1. A workpiece quality estimation device is a workpiece quality estimation device for a machine that estimates the quality of a workpiece, wherein, The machine has a workpiece placement part for placing the workpiece, a motor for driving the workpiece placement part, a sensor for detecting the state of the motor, and a motor control part for controlling the motor according to the detected state of the motor. The workpiece mass estimation device includes: An identification part that identifies the value of the physical parameter of the driven body driven by the output of the motor according to the detected state of the motor, and continuously updates the identified value through iterative calculation; A storage part that continuously stores the continuously updated value of the physical parameter; An estimation part that estimates the mass of the workpiece according to the final value of the continuously updated value of the physical parameter; And A display that displays a graph showing the change in the value of the physical parameter based on the data stored in the storage part, and displays the mass estimated by the estimation part.

2. The workpiece mass estimation device according to claim 1, wherein The display displays the graph and a switching part for performing and aborting the execution of estimating the mass.

3. The workpiece mass estimation device according to claim 1 or 2, wherein The display displays the graph and the date and time when the estimation of the mass is completed.

4. The workpiece mass estimation device according to any one of claims 1 to 3, wherein The display displays the graph and the temperature of the motor in real time.

5. The workpiece mass estimation device according to any one of claims 1 to 4, wherein The display displays the graph and an operation mode selection part for selecting the operation condition of the driven body.

6. The workpiece mass estimation device according to any one of claims 1 to 5, wherein The display displays the graph and indicates that the estimation of the mass has not been completed normally when the estimation of the mass of the workpiece has not been completed normally.

7. The workpiece mass estimation device according to any one of claims 1 to 6, wherein The display displays the graph and a reset part for initializing the estimated mass.

8. The workpiece mass estimation device according to any one of claims 1 to 7, wherein When the identified physical parameter is outside the specified range, the display displays the graph and an alarm.

9. The workpiece mass estimation device according to any one of claims 1 to 8, wherein The graph includes an inertia graph, a viscous friction coefficient graph, a Coulomb friction coefficient graph, and a spring constant graph, wherein the inertia graph represents the change in the inertia of the driven body, the viscous friction coefficient graph represents the change in the viscous friction coefficient in the transmission system that transmits the output of the motor to the workpiece placement part, the Coulomb friction coefficient graph represents the change in the Coulomb friction coefficient in the transmission system, the spring constant graph represents the change in the spring constant in the transmission system.

Images