Abnormality determination system and recording medium

Abstract

An abnormality determination system and program capable of detecting an abnormality of a machine tool with high precision are provided. The abnormality determination system includes a pre-reading section that pre-reads a machining program to generate command data, an advance position calculation section that calculates an advance position of a movable section of a machine tool based on the command data, an interference checking section that checks interference of the movable section of the machine tool with other sections of the machine tool, a motor information estimation section that estimates motor estimation information related to a motor of the machine tool based on the interference of the movable section with the other sections, an estimation precision decision section that decides estimation precision of the motor estimation information, a detection threshold decision section that decides a detection threshold for detecting an abnormality of the machine tool based on the motor estimation information and the estimation precision, a motor measurement section that acquires motor measurement information related to the motor, and a state determination section that determines a state of the machine tool based on the motor measurement information and the detection threshold.

Description

Technical Field

[0001] The present invention relates to an abnormality determination system and a program. Background Art

[0002] Conventionally, a numerical control device drives and controls a movable portion (eg, a control axis) of a machine tool according to a pre-generated machining program (NC program), thereby machining a workpiece or the like as a machining object via the movable portion.

[0003] During the operation of numerical control devices and machine tools, interference may occur between the movable parts of the machine tool or between the movable parts of the machine tool and other parts of the machine tool due to errors in the machining program, incorrect installation position of the workpiece relative to the machine tool, and incorrect input of tool offsets.

[0004] In order to prevent such interference, the following technology has been proposed: based on the advance position of the machine tool and the shape data of the movable part and other parts of the machine tool, the interference between the movable part and other parts of the machine tool is simulated, thereby detecting abnormalities in the machine tool (for example, refer to Patent Document 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-244256 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] The numerical control device described in Patent Document 1 simulates the movement of a machine tool based on simulation conditions that include the predicted position of the machine tool's movable parts and the machine tool's shape data. However, the numerical control device must perform the simulation before the actual movement of the machine tool, resulting in a limited processing time for the simulation. Therefore, when there is insufficient processing time, the numerical control device must reduce the simulation accuracy. Conversely, when there is sufficient processing time, the simulation can be performed with high accuracy. Furthermore, the accuracy of the simulation may also be affected by the specifications of the computer performing the simulation.

[0010] When simulation accuracy varies, the numerical controller needs to set a wide range of detection thresholds for detecting machine tool anomalies, assuming the simulation accuracy is poor. Consequently, even when the numerical controller can simulate with high accuracy, it sets a wide range of detection thresholds, reducing the accuracy of machine tool anomaly detection.

[0011] Therefore, there is a need for an abnormality determination system that can detect an abnormality of a machine tool with high accuracy even if there are variations in the accuracy of the simulation.

[0012] Means for solving problems

[0013] The abnormality determination system according to the present disclosure includes: a pre-reading unit that pre-reads a machining program and generates command data; a pre-position calculation unit that calculates a pre-position of a movable part of a machine tool based on the command data; an interference check unit that simulates the operation of the machine tool based on the pre-position and shape data of the machine tool to thereby check for interference between the movable part of the machine tool and other parts of the machine tool; a motor information estimation unit that estimates motor estimation information related to a motor of the machine tool based on the interference between the movable part and the other parts detected by the interference check unit; an estimation accuracy determination unit that determines an estimation accuracy of the motor estimation information; a detection threshold determination unit that determines a detection threshold for detecting an abnormality of the machine tool based on the motor estimation information and the estimation accuracy; a motor measurement unit that obtains motor measurement information related to the motor; and a state determination unit that determines the state of the machine tool based on the motor measurement information and the detection threshold.

[0014] The program involved in the present disclosure causes a computer to execute the following steps: pre-reading a machining program to generate instruction data; calculating a preliminary position of a movable part of a machine tool based on the instruction data; simulating the movement of the machine tool based on the preliminary position and shape data of the machine tool, thereby checking interference between the movable part of the machine tool and other parts of the machine tool; estimating motor estimation information related to a motor of the machine tool based on the interference between the movable part and the other parts; determining an estimation accuracy of the motor estimation information; determining a detection threshold for detecting an abnormality of the machine tool based on the motor estimation information and the estimation accuracy; obtaining motor measurement information related to the motor; and determining a state of the machine tool based on the motor measurement information and the detection threshold.

[0015] Effects of the Invention

[0016] According to the present invention, an abnormality in a machine tool can be detected with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing an overview of the abnormality determination system according to this embodiment.

[0018] Figure 2A This is a diagram showing a voxel model of a workpiece cut by a machine tool.

[0019] Figure 2B : is a diagram showing an example of a detection threshold.

[0020] Figure 3A This is a diagram showing a voxel model of a workpiece cut by a machine tool.

[0021] Figure 3B It is a diagram showing an example of the detection threshold.

[0022] Figure 4 This is a flowchart showing the processing flow of the abnormality determination system according to this embodiment. DETAILED DESCRIPTION

[0023] Hereinafter, an example of an embodiment of the present invention will be described. Figure 1 FIG is a diagram showing an overview of an abnormality determination system 1 according to this embodiment. The abnormality determination system 1 is intended to determine abnormalities in a machine tool. Figure 1 As shown, the abnormality determination system 1 includes a numerical control device 2 and a simulation device 3 .

[0024] Numerical controller 2 is a device for controlling machine tool 4 to cause it to perform predetermined machining operations, etc. Numerical controller 2 includes a machining program 21, a look-ahead unit 22, look-ahead block instruction data 23, an allocation processing unit 24, a movement instruction output unit 25, an acceleration / deceleration processing unit 26, a servo control unit 27, a preceding position calculation unit 28, a current position register 29, a motor measurement unit 30, a detection threshold determination unit 35, and a state determination unit 36.

[0025] Simulator 3 is used to check interference between the movable portion of machine tool 4 and other parts of machine tool 4 through simulation. Simulator 3 includes a preceding position receiving unit 31 , an interference checking unit 32 , a motor information estimating unit 33 , and an estimation accuracy determining unit 34 .

[0026] The machining program 21 is stored in a storage device such as a memory of the numerical controller 2 and is a program for causing the machine tool 4 to perform predetermined machining.

[0027] The pre-reading unit 22 pre-reads the machining program 21 and generates command data based on the machining program 21. Specifically, the pre-reading unit 22 generates pre-read block command data 23 as command data.

[0028] The pre-read block command data 23 is a plurality of data obtained by reading commands per block from the machining program 21 by the pre-read unit 22 and converting them into an executable format. The pre-read block command data 23 is stored in a storage device such as a memory of the numerical controller 2 .

[0029] The allocation processing unit 24 sequentially reads the pre-read block instruction data 23 for each program block and, based on the movement amount and speed of each axis specified in each program block, calculates the allocated movement amount instructed to the servo motor 41 of each axis for each allocation cycle. The allocation processing unit 24 updates the current position of the servo motor 41 of each axis by adding the calculated allocated movement amount to, for example, the current position register 29. Furthermore, the allocation processing unit 24 outputs the calculated allocated movement amount to the acceleration / deceleration processing unit 26 via the movement instruction output unit 25.

[0030] When an axis stop command is input from the simulation device 3, the movement command output unit 25 stops outputting the allocated movement amount in the movement command output from the allocation processing unit 24 to the acceleration / deceleration processing unit 26. Therefore, unless an axis stop command is input from the simulation device 3, the movement command output unit 25 outputs the movement command to the acceleration / deceleration processing unit 13.

[0031] The acceleration / deceleration processing unit 26 performs acceleration / deceleration processing based on the movement command, and outputs the movement command corresponding to the movement amount after the acceleration / deceleration processing to the servo control unit 27 .

[0032] The servo control unit 27 performs position and speed feedback control based on position and speed feedback from a position and speed detector attached to the servo motor 41 (or a movable part of the machine tool 4 driven by the servo motor 41) and the movement command output from the acceleration / deceleration processing unit 26. The servo control unit 27 also controls the drive of the servo motor 41 via a servo amplifier.

[0033] In addition, Figure 1 Although only one servo motor 41 is shown in FIG, the servo control unit 27 similarly controls the servo motor 41 of each axis in the machine tool 4. That is, the servo control unit 27 controls the position and speed of the servo motor 41 of each axis.

[0034] The advance position calculation unit 28 calculates the advance position of the movable part of the tool machine 4 based on the pre-read block command data 23 as command data.

[0035] Specifically, advance position calculation unit 28 calculates the advance position of the movable part of machine tool 4 based on the current position of the movable part of machine tool 4, a preset advance time, and pre-read block command data 23. Here, the advance position of the movable part of machine tool 4 represents the position that the movable part, driven by servo motor 41, would move from its current position after the advance time.

[0036] Then, the advance position calculation unit 28 outputs the advance time and the coordinate values ​​of the advance position to the simulation device 3 in order to check the interference between the movable portion of the machine tool 4 and other parts of the machine tool 4 .

[0037] Here, the movable part of the machine tool 4 refers to the workpiece, tool (e.g., cutting tool), and movable parts other than the workpiece and tool driven by the servo motor 41. In addition, the other parts of the machine tool 4 refer to parts other than the workpiece, tool, and movable parts driven by the servo motor 41.

[0038] Current position register 29 registers the current position of the movable part of machine tool 4. The current position of the movable part of machine tool 4 is sequentially updated by allocation processing unit 24.

[0039] The motor measuring unit 30 measures motor measurement information related to the servo motor 41. Specifically, the motor measuring unit 30 measures motor measurement information such as the motor current value and the load on the servo motor 41 and the spindle load estimated from the current value. Furthermore, the motor measuring unit 30 can also measure motor measurement information related to the spindle motor 42 in addition to the servo motor 41.

[0040] The preceding position receiving unit 31 of the simulation device 3 receives the preceding position of the movable part of the machine tool 4 calculated by the preceding position calculating unit 28 .

[0041] Interference checking unit 32 checks for interference between the movable portion of machine tool 4 and other parts of the machine tool based on the preceding position of the movable portion of machine tool 4 and the shape data of machine tool 4. Specifically, interference checking unit 32 simulates the operation of machine tool 4 based on simulation conditions that include the preceding position and the shape data of machine tool 4, thereby checking for interference between the movable portion of machine tool 4 and other parts.

[0042] Here, the shape data of the machine tool 4 is, for example, data based on the design data of the machine tool 4 , and is stored in a memory or the like of the numerical controller 2 .

[0043] Motor information estimating unit 33 estimates motor estimation information regarding the motor of machine tool 4 based on the interference between the movable part and other parts detected by interference detecting unit 32. Specifically, based on the interference between the movable part and other parts of machine tool 4, that is, a simulation of the operation of machine tool 4, motor information estimating unit 33 estimates motor estimation information including the load of servo motor 41, the current value of servo motor 41 estimated based on the load of servo motor 41, and the load and current value of the spindle.

[0044] The estimation accuracy determination unit 34 determines the estimation accuracy of the motor estimation information estimated by the motor information estimation unit 33. Specifically, the estimation accuracy determination unit 34 determines the estimation accuracy of the motor estimation information based on simulation conditions such as time resolution and shape data accuracy.

[0045] Next, detection threshold determination unit 35 of numerical controller 2 determines a detection threshold for detecting an abnormality in machine tool 4 based on the motor estimation information and the estimation accuracy. Specifically, detection threshold determination unit 35 determines the detection threshold to be a relatively small value when the estimation accuracy is relatively high, and determines the detection threshold to be a relatively large value when the estimation accuracy is relatively low.

[0046] State determination unit 36 ​​determines the state of machine tool 4 based on the motor measurement information measured by motor measuring unit 30 and the detection threshold determined by detection threshold determination unit 35. Specifically, state determination unit 36 ​​determines that machine tool 4 is operating abnormally if the motor measurement information exceeds the detection threshold, and determines that machine tool 4 is operating normally if the motor measurement information does not exceed the detection threshold.

[0047] Conventional simulation devices simulate the motion of machine tool 4 based on simulation conditions including the advance position of the movable part of the machine tool and the shape data of the machine tool. However, the simulation device must complete the simulation before the actual motion of the machine tool, so the processing time for the simulation is limited.

[0048] Therefore, conventional numerical controllers, when determining the detection threshold for detecting machine tool anomalies, must set a wide range of detection thresholds, assuming the simulation device has poor simulation accuracy. Consequently, even when the numerical controller can simulate with high accuracy, the detection threshold range is set wide, resulting in reduced accuracy in detecting machine tool anomalies.

[0049] Therefore, the abnormality determination system 1 of the present embodiment determines the detection threshold value based on the accuracy of the simulation, thereby improving the accuracy of detecting abnormalities in the machine tool 4 .

[0050] Figure 2A as well as Figure 3A is a diagram showing a voxel model of a workpiece cut by the machine tool 4. Figure 3A as well as Figure 3B It is a diagram showing an example of the detection threshold.

[0051] like Figure 2A as well as Figure 3A As shown, the simulation device 3 represents the workpiece cut by the machine tool 4 using voxel models M1 and M2. Here, the voxel models M1 and M2 are models that represent the shape of the object using a collection of tiny cubes.

[0052] Then, the interference checking unit 32 of the simulation device 3 uses the voxel models M1 and M2 to check the workpiece cut by the machine tool 4 (ie, other parts of the machine tool 4) and the movable parts of the machine tool 4 (eg, Figure 2A as well as Figure 3A The action of the cutting tool T) shown is simulated.

[0053] For example, the interference checker 32 simulates the cutting load and motor torque based on the geometric relationship between the voxel models M1 and M2, which are modeled as a workpiece, and the cutting tool T. While various methods exist for simulating the cutting load and motor torque using voxel models, the interference checker 32 of this embodiment uses known methods to simulate the cutting load and motor torque. Furthermore, as the cutting tool T proceeds, the interference checker 32 simulates the voxel models M1 and M2 so that only the cut portion remains.

[0054] The accuracy of the simulation depends on simulation conditions such as the size of voxels in the voxel models M1 and M2 and the time resolution, etc. Therefore, the interference check unit 32 adjusts the simulation conditions so that the simulation can be completed within a limited time.

[0055] The estimation accuracy determination unit 34 determines the estimation accuracy of the motor estimation information based on the adjusted simulation conditions. Figure 2A As shown, the size ratio of the voxels in the voxel model M1 as the simulation condition is Figure 3A When the voxel model M2 shown is thin, the estimation accuracy determination unit 34 determines the estimation accuracy of the motor estimation information (for example, the estimated value of the motor torque) to be a relatively high value.

[0056] Moreover, if Figure 2B As shown in the graph G1 of FIG, the detection threshold determination unit 35 determines the detection threshold to be a relatively small value when the estimation accuracy is relatively high. Figure 2B As shown, state determination unit 36 ​​determines the state of machine tool 4 based on motor measurement information (eg, actual measurement value of motor torque) and the detection threshold value determined by detection threshold value determination unit 35 .

[0057] Likewise, if Figure 3A As shown, the simulation device 3 represents the workpiece cut by the machine tool 4 by means of a voxel model M2. The simulation device 3 uses the voxel model M2 to simulate the workpiece cut by the machine tool 4 (i.e., other parts of the machine tool 4) and the movable parts of the machine tool 4 (e.g., Figure 3A The action of the cutting tool T) shown.

[0058] And, for example, Figure 3A As shown, the size ratio of the voxels in the voxel model M2 as the simulation condition is Figure 2A When the voxel model M1 shown is coarse, the estimation accuracy determination unit 34 determines the estimation accuracy of the motor estimation information (for example, the estimated value of the motor torque) to be a relatively low value.

[0059] like Figure 3BAs shown in graph G2, detection threshold determination unit 35 determines a relatively large detection threshold when the estimated accuracy is relatively low. Consequently, state determination unit 36 ​​determines the state of machine tool 4 based on motor measurement information (e.g., the actual value of motor torque) and the detection threshold determined by detection threshold determination unit 35.

[0060] Here, since the detection threshold is determined to be a relatively large value, state determination unit 36 ​​does not detect the actual value of the motor torque, which may be erroneously detected if the detection threshold remains at a relatively small value. In other words, it determines that the state of machine tool 4 is normal.

[0061] Therefore, when the estimation accuracy of motor estimation information (for example, estimated value of motor torque) is relatively low, abnormality determination system 1 can appropriately determine the state of machine tool 4 by setting the detection threshold to a relatively large value.

[0062] Figure 4 This is a flowchart showing the flow of processing of the abnormality determination system 1 according to the present embodiment.

[0063] In step S1 , the pre-reading unit 22 pre-reads the machining program 21 before the operation of the machine tool 4 , and generates pre-read block command data 23 as command data.

[0064] In step S2 , the advance position calculation unit 28 calculates the advance position of the movable part of the machine tool 4 based on the current position of the movable part of the machine tool 4 , a preset advance time, and the pre-read block command data 23 .

[0065] In step S3 , the interference checker 32 simulates the operation of the machine tool 4 based on simulation conditions including the preceding position and the shape data of the machine tool 4 , thereby checking for interference between the movable portion of the machine tool 4 and other portions.

[0066] In step S4 , the motor information estimating unit 33 estimates motor estimation information related to the motor of the machine tool 4 based on the interference between the movable part and other parts detected by the interference detecting unit 32 .

[0067] In step S5 , the estimation accuracy determination unit 34 determines the estimation accuracy of the motor estimation information estimated by the motor information estimation unit 33 .

[0068] In step S6 , detection threshold determination unit 35 determines a detection threshold for detecting an abnormality in machine tool 4 based on motor estimation information and estimation accuracy.

[0069] In step S7 , state determination unit 36 ​​determines the state of machine tool 4 based on the motor measurement information measured by motor measurement unit 30 and the detection threshold value determined by detection threshold value determination unit 35 .

[0070] As explained above, the abnormality determination system 1 of the present embodiment is provided with: the pre-reading section 22 that pre-reads the machining program 21, generates the pre-reading program block instruction data 23 as the instruction data; the advance position calculation section 28 that calculates the advance position of the movable section of the machine tool 4 based on the pre-reading program block instruction data 23; the interference checking section 32 that simulates the movement of the machine tool 4 based on the advance position and the shape data of the machine tool 4, thereby checking the interference of the movable section of the machine tool 4 with other sections of the machine tool 4; the motor information estimation section 33 that estimates the motor estimation information relating to the motor of the machine tool 4 based on the interference of the movable section with other sections checked by the interference checking section 32; the estimation accuracy decision section 34 that decides the estimation accuracy of the motor estimation information; the detection threshold decision section 35 that decides the detection threshold for detecting the abnormality of the machine tool 4 based on the motor estimation information and the estimation accuracy; the motor measurement section 30 that acquires the motor measurement information relating to the motor; and the state determination section 36 that determines the state of the machine tool 4 based on the motor measurement information and the detection threshold.

[0071] Thus, the abnormality determination system 1 decides the detection threshold according to the accuracy of the simulation, so that even if there is a deviation in the accuracy of the simulation, the abnormality of the machine tool 4 can be detected with high accuracy. Therefore, the abnormality determination system 1 can detect the abnormality of the machine tool 4 with high accuracy even if there is a deviation in the accuracy of the simulation in the case where there is a difference between the simulation of the movement of the machine tool 4 and the actual movement of the machine tool.

[0072] In addition, the detection threshold decision section 35 decides the detection threshold to be a relatively small value in the case where the estimation accuracy is relatively high, and decides the detection threshold to be a relatively large value in the case where the estimation accuracy is relatively low. Thus, the abnormality determination system 1 decides the detection threshold according to the accuracy of the simulation, so that the detection threshold for detecting the abnormality of the machine tool 4 can be set to an appropriate value.

[0073] In addition, the interference checking section 32 simulates the movement of the machine tool 4 based on the simulation conditions including the advance position and the shape data of the machine tool 4, thereby checking the interference of the movable section of the machine tool 4 with other sections of the machine tool 4. The estimation accuracy decision section 34 decides the estimation accuracy of the motor estimation information based on the simulation conditions. Thus, the abnormality determination system 1 can decide the estimation accuracy of the motor estimation information indicating the accuracy of the simulation, so that the abnormality of the machine tool 4 can be detected with high accuracy according to the accuracy of the simulation.

[0074] In addition, the state determination section 36 determines that the movement of the machine tool 4 is abnormal in the case where the motor measurement information exceeds the detection threshold, and determines that the movement of the machine tool 4 is normal in the case where the motor measurement information does not exceed the detection threshold.

[0075] Furthermore, abnormality determination system 1 includes a numerical controller 2 that controls machine tool 4 and a simulator 3 that simulates the operation of machine tool 4. Furthermore, numerical controller 2 includes a look-ahead unit 22, a forward position calculation unit 28, a motor measurement unit 30, a detection threshold determination unit 35, and a state determination unit 36, while simulator 3 includes an interference check unit 32, a motor information estimation unit 33, and an estimation accuracy determination unit 34. Thus, abnormality determination system 1 can detect abnormalities in machine tool 4 with high accuracy using numerical controller 2 and simulator 3.

[0076] While the embodiments of the present invention have been described above, the abnormality determination system 1 described above can be implemented using hardware, software, or a combination thereof. Furthermore, the control method performed by the abnormality determination system 1 described above can also be implemented using hardware, software, or a combination thereof. Here, implementation using software means that a computer reads a program and executes it.

[0077] The program can be stored and provided to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (read-only memories), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (programmable ROMs), EPROMs (erasable PROMs), flash ROMs, and RAMs (random access memories)).

[0078] The above-described embodiments are preferred embodiments of the present invention, but the scope of the present invention is not limited to the above-described embodiments, and the present invention can be implemented in various modified forms without departing from the spirit of the present invention.

[0079] Explanation of symbols

[0080] 1Abnormality determination system,

[0081] 2 numerical control device,

[0082] 3Simulation device,

[0083] 4. Machine tools,

[0084] 21 processing procedures,

[0085] 22 Pre-reading Department,

[0086] 23 Pre-read program block instruction data,

[0087] 24 Allocation Processing Department,

[0088] 25 movement command output unit,

[0089] 26 Acceleration and deceleration processing unit,

[0090] 27 Servo control unit,

[0091] 28 advance position calculation unit,

[0092] 29 current position register,

[0093] 30 Motor measurement unit,

[0094] 31 advance position receiving unit,

[0095] 32 Interference Inspection Department,

[0096] 33 motor information estimation unit,

[0097] 34 estimation accuracy determination unit,

[0098] 35 detection threshold determination unit,

[0099] 36. Status determination unit.

Claims

1. An abnormality determination system, characterized in that: have: A pre-reading unit that pre-reads a machining program and generates instruction data; a preceding position calculation unit for calculating a preceding position of a movable part of the tool machine based on the command data; an interference checking unit for simulating the movement of the machine tool based on the preceding position and the shape data of the machine tool, thereby checking for interference between the movable portion of the machine tool and other portions of the machine tool; a motor information estimating unit that estimates motor information related to the motor of the machine tool based on the interference between the movable portion and the other portion detected by the interference detecting unit; an estimation accuracy determination unit that determines an estimation accuracy of the motor estimation information; a detection threshold determination unit that determines a detection threshold for detecting an abnormality in the machine tool based on the motor estimation information and the estimation accuracy; a motor measuring unit that acquires motor measurement information related to the motor; and A state determination unit determines a state of the machine tool based on the motor measurement information and the detection threshold.

2. The abnormality determination system according to claim 1, characterized in that: The detection threshold determination unit determines the detection threshold to be a relatively small value when the estimation accuracy is relatively high, and determines the detection threshold to be a relatively large value when the estimation accuracy is relatively low.

3. The abnormality determination system according to claim 1 or 2, characterized in that: The interference checking unit simulates the movement of the machine tool based on simulation conditions including the preceding position and the shape data of the machine tool, thereby checking interference between the movable part of the machine tool and the other parts of the machine tool. The estimation accuracy determination unit determines the estimation accuracy of the motor estimation information based on the simulation condition.

4. The abnormality determination system according to any one of claims 1 to 3, characterized in that: The state determination unit determines that the operation of the machine tool is abnormal when the motor measurement information exceeds the detection threshold, and determines that the operation of the machine tool is normal when the motor measurement information does not exceed the detection threshold.

5. A computer-readable recording medium having a computer program recorded thereon, characterized in that: The computer program is used to cause a computer to execute the following steps: Pre-read the machining program and generate instruction data; calculating a pre-calculated position of a movable part of a tool machine according to the command data; Simulating the movement of the machine tool based on the preceding position and the shape data of the machine tool, thereby checking interference between the movable part of the machine tool and other parts of the machine tool; estimating motor estimation information related to a motor of the machine tool based on interference between the movable portion and the other portion; determining an estimation accuracy of the motor estimation information; determining a detection threshold for detecting an abnormality in the machine tool based on the motor estimation information and the estimation accuracy; obtaining motor measurement information related to the motor; and The state of the machine tool is determined based on the motor measurement information and the detection threshold.

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