tax system

Abstract

Control system (20), comprising: a data recipient (1311) who is designed to receive: support target object information representing information about a support target object (6) supported by a support (5) of an industrial machine (30); a holding state, which is a state in which the holding target object (6) is held by the holder (5); and machine information representing information about the industrial machine (30); and an analyzer (1312) configured to derive a cutoff frequency as a natural frequency of a machine configuration comprising a control target and the mount (5), wherein the cutoff frequency is set in a filtering process in a motor controller (1), wherein the motor controller (1) controls the control target, wherein the control target is provided in the industrial machine (30), wherein the natural frequency is generated in the machine configuration in a case where the mount target object (6) is mounted by the mount (5), wherein the analyzer (1312) is designed if the holding target object (6) and / or the holding state changes before the industrial machine (30) performs a machining operation: generate a geometric model for an object to be analyzed from the support target object information, the support state, and the machine information obtained by the data acquirer (1311) after the support target object (6) and / or the support state has changed; to perform a vibration analysis for the geometric model using a finite element method; and to derive the natural frequency of the machine configuration when the machining operation is carried out in a state in which the support target object (6) is held by the holder (5) of the industrial machine (30), wherein the holding target object (6) is a workpiece to be machined by the industrial machine (30), and the support target object information is information including a support position, a structure, and a material of the support target object (6).

Description

Technical area

[0001] The present disclosure relates to a control system that controls an industrial machine such as a machine tool. Technological background

[0002] A controller that controls the operation of an industrial machine, such as a machine tool, typically uses a feedback control method. The controller can continuously follow a target value sent from a host controller and cope with the effects of disturbances by adjusting the feedback control method.

[0003] However, even if the feedback control method is used, depending on the rigidity, mass, and the like of a control target, mechanical resonance may occur. If the feedback gain is set to a large value, mechanical resonance may increase and cause a control system to oscillate when mechanical resonance occurs. To suppress such a phenomenon, a method has been conventionally used in which a notch filter, which is a filter that attenuates only a specific frequency component, is provided in a control loop. However, in order to set a cutoff frequency, which is a specific frequency to be attenuated, that is, cut off in the notch filter, the frequency to be cut off must be obtained in advance by actual measurement, so a dedicated measuring instrument is required.In addition, some machine tools perform an operation of holding a support target such as a workpiece. In such a machine tool, the resonance frequency changes depending on characteristics such as structures and materials of a support target, and whether the support target is supported. That is, the resonance frequency changes when the support state changes. Therefore, there are cases where the above-described phenomenon cannot be sufficiently suppressed by the method in which the cutoff frequency is determined in advance using a dedicated measuring instrument.

[0004] To address the above-described problem, Japanese Patent No. JP 6 639 758 B1 discloses a control system that estimates a resonance frequency, which changes according to the characteristics and state of a support target, from a current command in a control loop, a position obtained from a sensor or the like, and feedback information regarding the current. The control system described in JP 6 639 758 B1 can suppress vibration even when a control target changes by setting the estimated resonance frequency as a cutoff frequency of a notch filter.

[0005] The prior art also includes DE 10 2018 208 544 A1, which discloses a servo motor control device that determines a change in the stiffness of a connecting mechanism. Brief description of the inventionTechnical problem

[0006] However, when a machine tool is in a state whose resonance frequency is unknown, it is necessary for the method described in JP 6 639 758 B1 to estimate a resonance frequency at which mechanical resonance has occurred by using data such as feedback information including a current command and a result of detection by a detector when mechanical resonance has occurred, after the mechanical resonance has actually occurred in an industrial machine such as the machine tool.

[0007] Therefore, it is necessary to perform a mechanical resonance generation operation to determine the cutoff frequency of the notch filter. This can have a negative impact on the industrial machine.

[0008] The present disclosure has been made in view of the foregoing, and it is an object of the present disclosure to obtain a control system capable of suppressing mechanical resonance of an industrial machine such as a machine tool without requiring the operation of actually generating mechanical resonance in the industrial machine to estimate a resonance frequency of mechanical resonance occurring according to a natural frequency that changes depending on a state of the industrial machine. Solution to the problem

[0009] This object is achieved by a control system having the combination of features of patent claim 1. Preferred developments can be found in the dependent claims. To solve the above-described problem and achieve the object, a control system of the present disclosure comprises a data acquirer and an analyzer. The data acquirer acquires: support target information, which represents information regarding a support target held by a support of an industrial machine; support state, which represents information regarding a support target held by a support; and machine information, which represents information regarding the industrial machine.The analyzer is configured to derive a cutoff frequency such as a natural frequency of a machine configuration including a control target and the fixture, wherein the cutoff frequency is set in a filtering process in a motor controller, wherein the motor controller is configured to control the control target provided in the industrial machine, wherein the natural frequency is generated in the machine configuration in a case where the fixture target object is held by the fixture. The analyzer is configured to derive the natural frequency of the machine configuration from the fixture target object information, the fixture state, and the machine information acquired by the data acquirer, wherein the natural frequency is generated when a machining operation is performed in a state where the fixture target object is held by the fixture of the industrial machine. Advantageous effects of the invention

[0010] The control system according to the present disclosure has an effect of making it possible to suppress mechanical resonance of an industrial machine such as a machine tool without the need for an operation of actually generating mechanical resonance in the industrial machine to estimate a resonance frequency of mechanical resonance occurring corresponding to a natural frequency that changes depending on the state of the industrial machine. Brief description of the drawings Fig. 1 is a diagram schematically illustrating an example of a configuration of a control system according to a first embodiment. Fig. 2 is a diagram schematically illustrating an example of a configuration of a filter generator in the control system according to the first embodiment. Fig. 3 is a diagram schematically illustrating an example of a configuration of an arithmetic device in the control system according to the first embodiment. Fig. 4 is a flowchart illustrating an example of a processing procedure to be performed in the filter generator in the control system according to the first embodiment. Fig. 5 is a diagram illustrating an example of a configuration of a processing circuit of the first embodiment. Fig. 6 is a diagram schematically illustrating another example of the configuration of the control system according to the first embodiment. Fig. 7 is a diagram schematically illustrating still another example of the configuration of the control system according to the first embodiment. Fig. 8 is a block diagram illustrating an example of a configuration of a computer system implementing the arithmetic device of the control system according to the first embodiment. Description of embodiments

[0011] Hereinafter, control systems according to an embodiment of the present invention will be described in detail with reference to the drawings. First embodiment

[0012] Fig. 1 is a diagram schematically illustrating an example of a configuration of a control system according to a first embodiment. A control system 20 of the first embodiment includes a motor controller 1 and a host controller 2 that controls the motor controller 1. The control system 20 controls a machine tool 30. The first embodiment assumes that the machine tool 30 serving as a control target to be controlled by the control system 20 is a machine tool that performs cutting work. However, a control target to be controlled by the control system 20 is not limited to a machine tool that performs cutting work, and it may be any other industrial machine configured to perform an operation of holding a workpiece 6 to be machined.

[0013] In the Fig. In the example shown in Figure 1, the machine tool 30 includes a motor 3, a speed reducer 8, a clamp 5, and a cutting tool 7. The machine tool 30 can hold the workpiece 6. The workpiece 6 is an example of a holding target that can be held by the machine tool 30. In addition, the workpiece 6 is to be machined by the machine tool 30. The clamp 5 is an example of a holder of the machine tool 30. More specifically, the machine tool 30 fixes the workpiece 6 using the clamp 5. The clamp 5 fixes the workpiece 6 when it receives a clamp signal from the host controller 2 indicating that the workpiece 6 is to be held. The motor 3 is controlled by the motor controller 1. The rotational movement of the motor 3 is transmitted to the clamp 5 via the speed reducer 6. As a result, the workpiece 6 rotates together with the clamp 5.The workpiece 6 is machined by the cutting tool 7 while rotating. Further, the position of the motor 3, that is, the rotational position of the motor 3, is detected by a detector 4. The position of the motor 3 detected by the detector 4 is input to the motor controller 1. The motor controller 1 directly controls the motor 3 and indirectly controls the speed reducer 8, which converts the rotational motion of the motor 3. The motor 3 and the speed reducer 8 are examples of control targets to be controlled by the motor controller 1. It should be noted that the control targets to be controlled by the motor controller 1 may include, in addition to the motor 3 and the speed reducer 8, elements that transmit the driving force of the motor 3, such as a ball screw (not shown).

[0014] Fig. 1 illustrates an example in which the clamping device 5 holds the workpiece 6 by means of a clamping mechanism. However, the holder is not limited to a holder that includes a clamping mechanism, and it may be a holder that holds the workpiece 6 by means of another mechanism. Furthermore, the clamping device 5 holds Fig. 1, the clamping device supports one end of the workpiece 6 extending in one direction, but it can support any part of the workpiece 6.

[0015] Further, although as an example in Fig. 1 illustrates a case where the machine tool 30 comprises a single set of machine parts including the motor 3, the speed reducer 8, the clamping device 5, and the cutting tool 7, the machine tool 30 may comprise two sets of machine parts. In this case, the sets of machine parts each comprising the motor 3, the speed reducer 8, the clamping device 5, and the cutting tool 7 may be arranged symmetrically. As a result, there are cases where a state in which both sets of machine parts hold the workpiece 6 is changed to a state in which one of the sets of machine parts holds the workpiece 6 and the other set of machine parts does not hold the workpiece 6. In such a case, the resonance frequency of the entire machine tool 30 changes.

[0016] The host controller 2 generates a command, a control signal, control information, and the like for controlling the machining to be performed by the machine tool 30. More specifically, the host controller 2 generates a position command, which is a command related to the position of the motor 3, and outputs the position command to the motor controller 1. In one example, the host controller 2 generates a command, a control signal, control information, and the like for controlling the machining to be performed by the machine tool 30 according to a machining program. The motor controller 1 generates a current for controlling the motor 3 based on the position command received from the host controller 2 and the position of the motor 3 input from the detector 4, and outputs the current to the motor 3.

[0017] In addition, the host controller 2 generates a control signal indicating whether the workpiece 6 is to be clamped or released by the clamping device 5, and outputs the control signal to the clamping device 5. Here, it is assumed that the control signal indicating whether the workpiece 6 is to be clamped or released is a clamp signal to be output while the workpiece 6 is clamped. The clamping device 5 performs an operation of clamping the workpiece 6 as long as it receives the clamp signal from the host controller 2, and performs the operation of releasing the workpiece 6 as long as it does not receive a clamp signal.Note that the control signal indicating whether to clamp or release the workpiece 6 is not limited to this example, and may be a signal to be output at the start and end of machining the workpiece 6, or it may be a signal indicating clamping and releasing the workpiece 6 by using a clamping value or the like of the signal. Furthermore, although an example has been described in which the workpiece 6 is clamped by the clamping device 5, any clamping method may be used as long as the host controller 2 can detect whether the workpiece 6 is clamped to the machine tool 30.

[0018] The host controller 2 detects the holding state of the workpiece 6. In one example, the holding state is information indicating whether the workpiece 6 is fixed to the machine tool 30. As an example, the holding state is information indicating whether the workpiece 6 is in the Fig. 1. This holding state is specified by the machining program in one example. The host controller 2 can determine the holding state of the workpiece 6 based on the machining program. Additionally, the holding state may be information that can be input by an operator of the machine tool 30. In one example, the operator inputs the holding state of the workpiece 6 using an input means (not shown) of the host controller 2. Alternatively, the motor controller 1 may include input means for allowing the operator to input the holding state of the workpiece 6 to the motor controller 1.Further, when machining is performed using the machine tool 30, workpiece information, which is information regarding the workpiece 6, and machine information, which is information regarding the machine tool 30, are input as machining conditions. The host controller 2 controls the machining to be performed by the machine tool 30 based on the machining conditions. The workpiece information includes the fixture position, structure, and material of the workpiece 6. The workpiece information corresponds to fixture target information. The fixture position is information indicating a distance from an end of the workpiece 6 to a point on the workpiece 6 at which the workpiece 6 is held by the chuck 5. In the example shown in FIG. Fig. In the example shown in Fig. 1, a distance from an end at which the workpiece 6 is not held to an end, which is a point on the workpiece 6 at which the workpiece 6 is held by the clamp 5, is used as the clamping position. The structure is information indicating the shape of the workpiece 6. The material is information indicating a material of the workpiece 6. The machine information is information regarding the machine tool 30, and includes the inertia and structures of: the motor 3 as a control target to be controlled by the motor controller 1; the speed reducer 8 that changes the speed of the motor; and the clamp 5 that holds the workpiece 6.The host controller 2 outputs to the motor controller 1: the holding state of the workpiece 6; the workpiece information, which is information regarding the workpiece 6; and the machine information, which is information regarding the machine tool 30. The workpiece information and the machine information may also be determined based on the machining program or may be information that can be input by the operator. Note that the holding target object information is information representing information regarding the holding target object, such as the workpiece 6. In addition, the machine information is information representing information regarding an industrial machine, such as the machine tool 30.

[0019] Next, a configuration of the engine control 1 will be described. As in Fig. 1, the motor controller 1 includes a position control unit 11, a speed control unit 12, a filter generator 13, a current control unit 14, and a speed conversion unit 15. The position control unit 11 calculates a speed command based on the position command received from the host controller 2 and the position input from the detector 4, and outputs the speed command to the speed control unit 12. Specifically, the speed command is calculated based on a difference between the position command and the position input from the detector 4. The speed conversion unit 15 calculates a speed by differentiating the position input from the detector 4 and outputs the calculated speed to the speed control unit 12.

[0020] The speed control unit 12 calculates a current command based on the speed command and the speed input from the speed conversion unit 15, and outputs the current command to the filter generator 13. Specifically, the speed control unit 12 calculates the current command based on a difference between the speed command and the speed input from the speed conversion unit 15. That is, the speed control unit 12 is a command generator that generates a command for controlling the machine tool 30 through feedback control. Specifically, this command is a command for controlling the motor 3 of the machine tool 30 through feedback control. In the first embodiment, an example will be described in which the filter generator 13, to be described below, performs a filtering process on a current command for controlling the motor 3.Meanwhile, the current command is an example of a command for controlling the machine tool 30 configured to support the support target object by feedback control. Thus, the filtering process of the first embodiment only needs to be applied to a command for controlling the motor provided in the machine tool 30, and such a command is not limited to the current command.

[0021] The filter generator 13 performs a filtering process in response to a command for controlling the machine tool 30 by feedback control. That is, in this example, the filter generator 13 performs a filtering process in response to a current command and outputs the current command that was the subject of the filtering process to the current control unit 14. The filtering process to be performed in the filter generator 13 is a filtering process for attenuating, that is, cutting off a component of a cutoff frequency, which is a specific frequency. By setting a frequency at which resonance occurs in the machine tool 30, which is the resonance frequency, as the cutoff frequency to be cut off by the filter generator 13, it is possible to suppress mechanical resonance, that is, to reduce the mechanical resonance.Meanwhile, the frequency at which mechanical resonance occurs varies depending on the natural frequency of a machine configuration of the machine tool 30, which includes the clamping device 5 and the control target to be controlled by the motor controller 1. The natural frequency depends on the support state of the workpiece 6 in which the workpiece 6 is held by the machine tool 30, the structure and material of the workpiece 6, and the like. Therefore, if the support state of the workpiece 6, the structure and material of the workpiece 6, and the like are not taken into account when determining the cutoff frequency to be removed by the filter generator 13, resonance cannot be suppressed in some cases depending on the support state of the workpiece 6, the structure and material of the workpiece 6, and the like.Therefore, in the first embodiment, the filter generator 13 determines the cutoff frequency to be removed by the filtering process based on the workpiece information, the holding state, and the machine information obtained from the host controller 2. Thus, in the first embodiment, it is possible to determine the cutoff frequency by considering the holding state of the workpiece 6, the structure and material of the workpiece 6, and the like. Therefore, even if the natural frequency of the workpiece 6 changes, mechanical resonance can be suppressed. Details of the filter generator 13 will be described below. In one example, the holding state of the workpiece 6 changes from a state in which the workpiece 6 is held by each of two sets of machine parts to a state in which the workpiece 6 is released from one of the sets of machine parts and held by the other set of machine parts.

[0022] The current control unit 14 controls a current to be output to the motor 3 based on the current command output from the filter generator 13. The current command to be output from the filter generator 13 is a current command obtained by the filter generator by removing the cutoff frequency from the current command output from the speed control unit 12. The motor 3 rotates according to the current output from the current control unit 14. Based on the above-described operation, the motor controller 1 can control the motor 3 in such a manner as to position the motor according to the position command received from the host controller 2.As a result of controlling the motor 3 in such a manner as to bring the motor into a position according to the position command, it is possible to control the workpiece 6 in such a manner as to bring the workpiece 6 into a desired position by means of the speed reducer 8 and the clamping device 5.

[0023] Next, details of the filter generator 13 will be described. The filter generator 13 obtains an oscillation frequency using information including workpiece information, fixture state, and machine information, and performs a filtering process in response to a current command according to the oscillation frequency. The filter generator 13 includes an arithmetic device that derives a natural frequency from information including the workpiece information, fixture state, and machine information through vibration analysis using a finite element method (FEM) model based on a finite element method. Since vibration analysis using the finite element method model is a well-known technology, its description will be omitted.

[0024] Fig. 2 is a diagram schematically illustrating an example of a configuration of the filter generator in the control system according to the first embodiment. The filter generator 13 includes an arithmetic device 131 and a notch filter 132. The arithmetic device 131 derives the natural frequency of the machine configuration by inputting the workpiece information, the fixture state, and the machine information obtained from the host controller 2. When deriving the natural frequency, the arithmetic device 131 generates a geometric model for an object to be analyzed from the workpiece information, the fixture state, and the machine information, and performs vibration analysis using the FEM model for this geometric model. The notch filter 132 performs a filtering process on a current command by using the natural frequency output from the arithmetic device 131 as a cutoff frequency.In one example, the filter generator 13 is a functional block that causes an integrated circuit (IC), a microcomputer, or the like to function as the filter generator 13. The functional block functions as the notch filter 132 as a result of adjusting the cutoff frequency derived from the arithmetic device 131.

[0025] Fig. 3 is a diagram schematically illustrating an example of a configuration of the arithmetic device in the control system according to the first embodiment. The arithmetic device 131 includes a data acquirer 1311 and an FEM analyzer 1312.

[0026] The data acquirer 1311 acquires the workpiece information, the fixture state, and the machine information regarding the workpiece 6 from the host controller 2 as input data to be used in the vibration analysis using the FEM model, and inputs the input data to the FEM analyzer 1312.

[0027] The FEM analyzer 1312 derives a cutoff frequency, to be set in a filtering process in the motor controller 1, which controls the control target provided in the machine tool 30, as the natural frequency of the machine configuration to be generated when the workpiece 6 is held. Specifically, the FEM analyzer 1312 derives, from the workpiece information, the holding state, and the machine information acquired by the data acquirer 1311, as the cutoff frequency, the natural frequency of the machine configuration to be generated when a machining operation is performed in a state where the workpiece 6 is held by the clamp 5 of the machine tool 30. At this time, the FEM analyzer 1312 derives the natural frequency by performing vibration analysis and using the finite element method.That is, the FEM analyzer 1312 derives a cutoff frequency to be applied to the notch filter 132 by performing vibration analysis on the input data input from the data acquirer 1311 using the FEM model based on the finite element method. The FEM analyzer 1312 corresponds to an analyzer.

[0028] Fig. 4 is a flowchart illustrating an example of a procedure of processing to be performed in the filter generator in the control system according to the first embodiment. The data acquirer 1311 of the arithmetic device 131 acquires data (step S11). Specifically, the data acquirer 1311 of the arithmetic device 131 acquires, as input data to be used in vibration analysis, workpiece information, a support state, and machine information relating to the workpiece 6 held by the machine tool 30, and inputs the input data to the FEM analyzer 1312. Here, the data acquirer 1311 acquires the workpiece information, the support state, and the machine information relating to the workpiece 6 from the host controller 2.

[0029] The FEM analyzer 1312 derives a natural frequency, which is an oscillation frequency for a case where the workpiece 6 is held by the machine tool 30, by performing a vibration analysis using the FEM model based on the input data (step S12).

[0030] Next, the FEM analyzer 1312 outputs the natural frequency derived in step S12 to the notch filter 132 (step S13). The notch filter 132 makes adjustments according to the data output from the FEM analyzer 1312 (step S14). More specifically, the notch filter 132 sets the natural frequency calculated by the arithmetic device 131 as a cutoff frequency and performs a filtering process on the current command. After that, the process ends.

[0031] Based on the above-described operation, the filter generator 13 can suppress a natural frequency corresponding to a combination of the workpiece information, the fixture state, and the machine information through the filtering process. Thus, even if the workpiece 6, which is a fixture target, and / or the fixture state changes, it is possible to suppress mechanical resonance of the machine tool 30. That is, even if the workpiece 6 is replaced or the workpiece 6 being held is released during machining, after the change in the workpiece 6 and / or the fixture state, a natural frequency corresponding to a combination of the workpiece information, the fixture state, and the machine information is calculated by the arithmetic device 131 and set in the notch filter 132.Therefore, mechanical resonance of the machine tool 30 can be suppressed even after the change. Since the control system 20 calculates the natural frequency corresponding to the combination of the workpiece information, the fixture state, and the machine information using the arithmetic device 131, a cutoff frequency can be derived without requiring an operation to actually generate mechanical resonance in the machine tool 30.

[0032] A hardware configuration of the motor controller 1 will now be described. Each unit of the motor controller 1 is implemented by a circuit. The power control unit 14 includes a converter circuit that converts AC power into DC power, or an inverter circuit that converts DC power into desired AC power. As a result, the power control unit 14 supplies power to the motor 3 in such a way that it follows a power command. The position control unit 11, the speed control unit 12, the filter generator 13, and the speed conversion unit 15 are implemented by a processing circuit. The processing circuit may be a circuit including a processor or may be dedicated hardware.

[0033] If the processing circuit is a circuit comprising a processor, the processing circuit is, for example, a control circuit comprising a processor and a memory. Fig. 5 is a diagram illustrating an example of a configuration of the processing circuit of the first embodiment. Fig. The processing circuit 100 shown in Figure 5 comprises a processor 101 and a memory 102. In a case where the position control unit 11, the speed control unit 12, the filter generator 13 and the speed conversion unit 15 are implemented by the control circuit, these units are implemented by the processor 101, which reads and executes a program stored in the memory 102. That is, in a case where the position control unit 11, the speed control unit 12, the filter generator 13 and the speed conversion unit 15 are implemented by the Fig. 5, the functions of these units are implemented through the use of a program, which is software. The memory 102 is also used as a work area for the processor 101. The processor 101 is a central processing unit (CPU) or the like. In one example, the memory 102 corresponds to a non-volatile or volatile semiconductor memory, such as a random access memory (RAM), a read-only memory (ROM), a flash memory, or a magnetic disk.

[0034] In a case where the position control unit 11, the speed control unit 12, the filter generator 13, and the speed conversion unit 15 are each implemented by dedicated hardware, the processing circuit is, for example, a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). Note that the position control unit 11, the speed control unit 12, the filter generator 13, and the speed conversion unit 15 may be implemented by a combination of a processing circuit including a processor and dedicated hardware. The position control unit 11, the speed control unit 12, the filter generator 13, and the speed conversion unit 15 may be implemented by multiple pieces of processing circuitry.

[0035] It is noted that the host controller 2 in the Fig. 1, the filter generator 13 of the motor controller 1 is supplied with the workpiece information, the holding state, and the machine information relating to the workpiece 6 held by the clamping device 5, which is a control target to be controlled by the motor controller 1.

[0036] However, the workpiece information, the fixture state, and the machine information related to the workpiece 6 can be input via the input means (not shown) of the motor controller 1. In this case, the control system 20 includes the motor controller 1 for setting the cutoff frequency.

[0037] Furthermore, the tax system includes 20 in the Fig. In the example shown in Figure 1, the engine controller 1 and the host controller 2 are included, and the filter generator 13 of the engine controller 1 includes the arithmetic device 131 that calculates a natural frequency. However, the configuration of the control system 20 is not limited to this.

[0038] Fig. Fig. 6 is a diagram schematically illustrating another example of the configuration of the control system according to the first embodiment. Note that the same components as those described above are denoted by the same reference numerals, and their description will therefore be omitted. Fig. The control system 20a shown in Figure 6 differs from that shown in Fig. 1 in that the filter generator 13 of the engine controller 1 does not include the arithmetic device 131, and the host controller 2 includes an arithmetic device 21 that calculates a natural frequency. The configuration of the arithmetic device 21 is similar to that shown in Fig. 3. In this case, a data acquirer of the arithmetic device 21 of the host controller 2 acquires workpiece information, a fixture state, and machine information relating to the workpiece 6 held by the clamping device 5, and an FEM analyzer derives the natural frequency of a machine configuration in the machine tool 30 having the workpiece 6 defined by the workpiece information, the fixture state, and the machine information using an FEM model. The arithmetic device 21 then sets the derived natural frequency in the filter generator 13 of the motor controller 1.

[0039] Fig. Fig. 7 is a diagram schematically illustrating yet another example of the configuration of the control system according to the first embodiment. Note that the same components as those described above are denoted by the same reference numerals, and their descriptions are therefore omitted. Fig. The control system 20b shown in Figure 7 further includes an arithmetic device 50 in addition to the motor controller 1 and the host controller 2. The motor controller 1, the host controller 2, and the arithmetic device 50 are connected via a communication line, and the arithmetic device 50 can communicate with the host controller 2 and the motor controller 1. In addition, the filter generator 13 of the motor controller 1 does not include the arithmetic device 131. The configuration of the arithmetic device 50 is similar to that shown in Fig. 3. In this example, a data acquirer of the arithmetic device 50 acquires workpiece information, a fixture state, and machine information relating to the workpiece 6 held by the clamping device 5. An FEM analyzer derives, by using an FEM model, the natural frequency of a machine configuration in the machine tool 30 having the workpiece 6, which is defined by the workpiece information, the fixture state, and the machine information. The FEM analyzer of the arithmetic device 50 then sets the derived natural frequency in the filter generator 13 of the motor controller 1.

[0040] In this case, the arithmetic device 50 comprises, for example, a computer system. That is, a program, which is a computer program in which a process for deriving a natural frequency has been described, is executed on the computer system. As a result, the computer system functions as the arithmetic device 50 of Fig. 7. Fig. 8 is a block diagram illustrating an example of a configuration of the computer system implementing the arithmetic device of the control system according to the first embodiment. As shown in Fig. 8, the computer system comprises a control unit 81, an input unit 82, a storage unit 83, a display unit 84, a communication unit 85, and an output unit 86, which are connected via a system bus 87.

[0041] In Fig. 8, the control unit 81 is, for example, a processor such as a CPU, and executes a program in which processing to be performed in the arithmetic device 50 according to the first embodiment has been written. Note that part of the control unit 81 may be implemented by dedicated hardware such as a graphics processor (GPU) or an FPGA. The input unit 82 includes a keyboard, a mouse, and the like, and is used by a user of the computer system to input various types of information. The storage unit 83 includes various memories such as RAM and ROM, and a storage device such as a hard disk, and stores a program to be executed by the above-described control unit 81, necessary data obtained during the execution of a process, and the like.Furthermore, the storage unit 83 is also used as a temporary storage area for the program. The display unit 84 includes a display, a liquid crystal display panel, or the like, and displays various screen displays for the user of the computer system. The communication unit 85 includes a receiver and a transmitter that perform communication processing. The output unit 86 is a printer, a speaker, or the like. It should be noted that . Fig. 8 is an example, and that the configuration of the computer system is not limited to the example of Fig. 8 is limited.

[0042] An example of an operation to be performed by the computer system until the above-described program becomes executable will now be described. In the computer system having the above-described configuration, a computer program is installed in the storage unit 83, for example, from a compact disc (CD-ROM) inserted into a CD-ROM drive (not shown) or from a digital versatile disc (DVD-ROM) inserted into a DVD-ROM drive (not shown). Then, the program read from the storage unit 83 is stored in a main memory area of ​​the storage unit 83 at the time of program execution. In this state, the control unit 81 performs processing according to the program stored in the storage unit 83, such as the arithmetic device 50 of Fig. 7.

[0043] It should be noted that in the above description, the program in which the processing to be performed in the arithmetic device 50 was described was provided using a CD-ROM or DVD-ROM as a recording medium, but the manner of providing the program is not limited to this. For example, a transmission medium such as the Internet via the communication unit 85 may be used to provide the program, depending on the configuration of the computer system, the capacity of the provided program, and the like.

[0044] In one example, this computer program causes the computer system to Fig. 4 to carry out the processing procedure shown.

[0045] As described above, in the control system 20, 20a, and 20b according to the first embodiment, it is possible to obtain by calculation the type of vibration of the machine configuration of the machine tool 30 reflecting the support state of the workpiece 6 from the workpiece information, the support state, and the machine information regarding the workpiece 6, by using a geometric model reflecting a state in which the workpiece 6 is actually supported in the machine tool 30, the shape and material of the workpiece 6, and the machine information regarding the machine tool 30.In the conventional technique, a machining operation is performed in a state where the workpiece 6 is held by the machine tool 30, and a resonance frequency at which mechanical resonance has actually occurred is obtained through feedback control by using data such as feedback information including a current command and a detection result by a detector. As a result, the obtained resonance frequency is set as a cutoff frequency in the notch filter 132. However, in the first embodiment, it is possible to calculate a natural frequency without using feedback control and set a calculation result in the filter generator 13 of the motor controller 1 before the machine tool 30 actually performs a machining operation, as described above.As a result, in order to obtain a resonance frequency, it is not necessary to perform an operation in which a machining operation is performed in the machine tool 30 that holds the workpiece 6 to actually cause mechanical resonance, and thus the mechanical resonance is suppressed. It is thus possible to suppress the occurrence of vibration at the natural frequency of the workpiece 6 from the start of the machining operation. That is, the first embodiment achieves the effect of allowing the suppression of mechanical resonance of an industrial machine without requiring an operation for estimating the resonance frequency of the mechanical resonance that occurs according to a natural frequency that changes depending on the state of the industrial machine such as the machine tool 30.In addition, since it is not necessary to generate mechanical resonance to estimate a natural frequency after the state change, it is possible to prevent mechanical resonance from exerting an adverse effect on the machine tool 30.

[0046] The configurations set forth in the above embodiments show examples, and it is possible to combine the configurations with other known technologies, and it is also possible to partially omit or modify the configurations without departing from the scope of the present disclosure. List of reference symbols 1 engine control; 2 Host control; 3 engine; 4 detector; 5 clamping device; 6 workpiece; 7 cutting tool; 8 speed reducers; 11 Position control unit; 12 speed control unit; 13 filter generator; 14 Power control unit; 15 speed conversion unit; 20, 20a, 20b tax system; 21, 50, 131 arithmetic device; 30 machine tools; 132 notch filters; 1311 data recipients; 1312 FEM analyzer.

Claims

[1] Control system (20), comprising: a data recipient (1311) who is designed to receive: support target object information representing information about a support target object (6) supported by a support (5) of an industrial machine (30); a holding state, which is a state in which the holding target object (6) is held by the holder (5); and machine information representing information about the industrial machine (30); and an analyzer (1312) configured to derive a cutoff frequency as a natural frequency of a machine configuration comprising a control target and the mount (5), wherein the cutoff frequency is set in a filtering process in a motor controller (1), wherein the motor controller (1) controls the control target, wherein the control target is provided in the industrial machine (30), wherein the natural frequency is generated in the machine configuration in a case where the mount target object (6) is mounted by the mount (5), wherein the analyzer (1312) is designed if the holding target object (6) and / or the holding state changes before the industrial machine (30) performs a machining operation: generate a geometric model for an object to be analyzed from the support target object information, the support state, and the machine information obtained by the data acquirer (1311) after the support target object (6) and / or the support state has changed; to perform a vibration analysis for the geometric model using a finite element method; and to derive the natural frequency of the machine configuration when the machining operation is carried out in a state in which the support target object (6) is held by the holder (5) of the industrial machine (30), wherein the holding target object (6) is a workpiece to be machined by the industrial machine (30), and the support target object information is information including a support position, a structure, and a material of the support target object (6). [2] The control system (20) according to claim 1, wherein the support position is information indicating a distance from an end of the support target object (6) to a point on the support target object (6) at which the support target object (6) is supported by the support (5). [3] The control system (20) according to claim 1 or 2, wherein the mount state is information indicating whether the mount target object (6) is fixed to the mount (5). [4] Control system (20) according to one of claims 1 to 3, wherein the machine information is information that includes structures and inertia of: a motor (3) included in the control target to be controlled by the motor control (1); a speed reducer configured to change a speed of the motor (3); and the holder (5) which is designed to hold the holding target object (6). [5] The control system (20) according to any one of claims 1 to 4, wherein the analyzer (1312) is configured to obtain the natural frequency by performing vibration analysis using a finite element method based on the support target information, the support state, and the machine information. [6] Control system (20) according to one of claims 1 to 5, further comprising: a filter generator (13) configured to apply the filtering process using the cutoff frequency to a command for controlling the industrial machine (30) through feedback control to eliminate the oscillation of the natural frequency derived from the analyzer (1312).

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