Control device and control method

Abstract

A control device according to the present disclosure comprises: a vibration application signal generation unit that generates a vibration application signal for applying vibration to a motor which drives a drive unit provided to an industrial machine; a control unit that positions the motor at a predetermined diagnosis start position, and that controls a diagnosis operation in which the vibration application signal is used to diagnose a frequency characteristic; a data acquisition unit that acquires at least feedback data obtained from the vibration application signal and the diagnosis operation; and a frequency characteristic calculation unit that calculates, on the basis of the feedback data, a resonance curve which indicates the frequency characteristic. Before performing the control related to the diagnosis operation, the control unit controls a prior operation in which an operation for positioning the motor at one end of a prescribed prior operation range and then positioning the motor at another end of the prior operation range is executed at least once, and subsequently the control unit positions the motor at the diagnosis start position and starts the diagnosis operation.

Description

Control device and control method

[0001] The present disclosure relates to a control device and a control method.

[0002] It is well known to diagnose the condition of a drive unit provided in industrial machinery by analyzing the frequency characteristics (resonance curve). The condition of the drive unit is diagnosed, for example, for mechanical resonance points, stability, and responsiveness, and the diagnostic results are utilized for preventive maintenance of the drive unit. Here, the frequency characteristics are measured by a diagnostic operation (frequency sweep operation) that applies a predetermined input signal to the drive unit to be controlled and observes the output signal.

[0003] A diagnostic operation is performed to drive a drive mechanism, and the frictional force is identified from the frequency response (frequency characteristics of the present application) of the drive mechanism based on the motor drive current, thereby diagnosing the state of the drive mechanism. Furthermore, the tension value of a belt that transmits power to industrial machinery is estimated based on data obtained from the diagnostic operation, and the degree of damage to the belt is diagnosed. Analyzing the frequency characteristics obtained by performing a diagnostic operation and diagnosing the state of a drive device in this manner is well known (e.g., Patent Documents 1 and 2, etc.).

[0004] JP 2020-038172 A JP 2021-076395 A

[0005] If the environmental conditions of the industrial machinery (e.g., room temperature, humidity, etc.) and the operating conditions related to the diagnostic operation (e.g., operation command values ​​such as motor rotation speed, the configuration of drive parts such as reducers provided in the drive unit, the rigidity of the drive unit, the magnitude of the load applied to the drive unit, etc.) are the same, the frequency characteristics obtained by the diagnostic operation will produce the same analysis results. However, in the past, the diagnostic operation was performed after the operator adjusted the position of the drive unit to the position where the diagnostic operation would be performed, which resulted in differences in the meshing state (e.g., backlash, play, rattle, etc.) of the power transmission parts such as belts, pulleys, and gears provided in the drive unit at the start of the diagnostic operation.

[0006] As a result, each time a diagnostic operation is performed, differences occur in the analysis results of the frequency characteristics, such as the shape of the resonance curve graph and the resonance point obtained by analyzing the frequency characteristics obtained by the diagnostic operation, and there are issues with the accuracy and reproducibility of the analysis results.It is desired to automatically position the position of the drive unit at a predetermined diagnostic start position when starting a diagnostic operation, thereby improving the analysis accuracy of the frequency characteristics and the reproducibility of the analysis results.

[0007] The control device of an injection molding machine according to the present disclosure solves the above problem by, when analyzing the frequency characteristics of a prime mover that drives a drive unit equipped in industrial machinery, positioning the prime mover at one end of a predetermined pre-operating range, then positioning it at the other end of the pre-operating range, and then positioning the prime mover at a diagnostic start position to start diagnostic operation.

[0008] One aspect of the present disclosure is a control device comprising: a vibration signal generation unit that generates a vibration signal that vibrates a prime mover that drives a drive unit provided in industrial machinery; a control unit that positions the prime mover at a predetermined diagnosis start position and controls a diagnostic operation that diagnoses the frequency characteristics using the vibration signal; a data acquisition unit that acquires at least the vibration signal and feedback data obtained from the diagnostic operation; and a frequency characteristic calculation unit that calculates a resonance curve that indicates the frequency characteristics based on the feedback data, wherein the control unit controls a pre-operation that performs at least one operation of positioning the prime mover at one end of a predetermined pre-operation range and then positioning it at the other end of the pre-operation range before controlling the diagnostic operation, and then positions the prime mover at the diagnosis start position and starts the diagnostic operation.

[0009] FIG. 1 is a schematic hardware configuration diagram of a control device according to an embodiment of the present disclosure. FIG. 2 is a schematic configuration diagram of an injection molding machine. FIG. 3 is a perspective view of a belt and a pulley which are power transmission means equipped in the injection molding machine. FIG. 4 is a block diagram showing the schematic functions of a control device according to a first embodiment. FIG. 5 is a graph illustrating a position change of a servo motor in a diagnostic operation of an injection molding machine. FIG. 6 is a graph illustrating a position change of a servo motor in a pre-operation related to a diagnostic operation. FIG. 7 is a graph illustrating a position change of a servo motor in a pre-operation related to another diagnostic operation. A schematic diagram of a toothed belt and a toothed pulley. FIG. 8 is a block diagram showing the schematic functions of a control device according to a second embodiment. FIG. 9 is a screen configuration diagram showing an example of a setting screen for a pre-operation range.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [First Embodiment] Fig. 1 is a schematic hardware configuration diagram showing the main parts of a control device according to a first embodiment of the present disclosure. The control device 1 according to this embodiment can be implemented as a control device that controls industrial machinery based on a control program, for example. In this embodiment, an example is shown in which the control device 1 is implemented as a control device that controls an injection molding machine 2, which is a type of industrial machinery.

[0011] The CPU 11 provided in the control device 1 according to this embodiment is a processor that controls the entire control device 1. The CPU 11 reads a system program stored in the ROM 12 via the bus 22 and controls the entire control device 1 in accordance with the system program. The RAM 13 temporarily stores temporary calculation data, display data, various data input from outside, and the like.

[0012] The nonvolatile memory 14 may be, for example, a battery-backed memory (not shown) or a solid-state drive (SSD), and retains its stored state even when the control device 1 is powered off. The nonvolatile memory 14 stores programs and data read from an external device 72 via the interface 15, programs and data input via the input device 71, and programs and data acquired from the injection molding machine 2 or other devices via the network 5. The stored data may include, for example, data related to physical quantities such as motor current, voltage, torque, position, speed, and acceleration of the drive unit detected by a sensor attached to the injection molding machine 2, injection cylinder temperature, resin pressure, flow rate, and flow velocity, mold temperature and pressure, mold temperature and pressure of the mold temperature regulator, position and speed of the molded product removal unit, and vibrations and sounds generated in various parts of the injection molding machine 2. The programs and data stored in the nonvolatile memory 14 may be loaded into the RAM 13 for execution or use. Various system programs, such as known analysis programs, are pre-loaded into the ROM 12.

[0013] The interface 15 is an interface for connecting the CPU 11 of the control device 1 to an external device 72 such as a USB device. For example, a system program, a program related to the operation of the injection molding machine 2, setting data, etc. are read from the external device 72. In addition, the programs and setting data created and edited within the control device 1 can be stored in an external storage means via the external device 72.

[0014] The interface 20 is an interface for connecting the CPU 11 of the control device 1 to a wired or wireless network 5. The network 5 may communicate using technologies such as serial communication such as RS-485, Ethernet (registered trademark), optical communication, wireless LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), etc. At least one injection molding machine 2 to be controlled, at least one other industrial machine 4, a fog computer 6, a cloud server 7, etc. are connected to the network 5, and data is exchanged between the network 5 and the control device 1.

[0015] The display device 70 displays various data read into the memory, data obtained as a result of executing programs, etc., output via the interface 17. An input device 71, which is comprised of a keyboard, pointing device, etc., passes instructions, data, etc. based on operations by an operator to the CPU 11 via the interface 18.

[0016] FIG. 2 is a schematic diagram of the injection molding machine 2. The injection molding machine 2 is mainly composed of a mold clamping unit 401 and an injection unit 402. The mold clamping unit 401 is equipped with a movable platen 416 and a fixed platen 414. A movable mold 412 is attached to the movable platen 416, and a fixed mold 411 is attached to the fixed platen 414. A servo motor 50 is attached to the mold clamping unit 401 as a prime mover. By driving the servo motor 50, a ball screw (not shown) is driven via power transmission means such as a belt 420 and a pulley 422, and the movable platen 416 can be moved forward or backward toward the fixed platen 414. Other examples of the prime mover include a hydraulic motor, a hydraulic cylinder, a linear motor, and a direct drive motor.

[0017] Figure 3 is a perspective view of a belt 420 and a pulley 422, which are power transmission means provided in the injection molding machine 2 shown in Figure 2. As shown in Figure 3, a toothed belt may be used as the belt 420, and a toothed pulley may be used as the pulley 422. A flat belt, a V-belt, a chain, or the like may also be used as the belt 420. Depending on the structure of the injection molding machine 2, a linear bushing, a ball screw, a spline coupling part, or the like may also be used as the power transmission means. Furthermore, a direct-coupled structure using a direct drive motor may also be used.

[0018] On the other hand, the injection unit 402 is made up of an injection cylinder 426, a hopper 436 that stores the resin material to be supplied to the injection cylinder 426, and a nozzle 440 provided at the tip of the injection cylinder 426. The injection unit 402 can move the injection cylinder 426 forward or backward toward the fixed platen 414 by driving a servo motor (not shown).

[0019] In a molding cycle for producing one molded product, the mold clamping unit 401 closes and clamps the mold by moving the movable platen 416, and the injection unit 402 presses the nozzle 440 against the fixed mold 411 and then injects the resin measured into the injection cylinder 426 into the mold. These operations are controlled by commands from a control device 1 (not shown).

[0020] Furthermore, sensors (not shown) are attached to each part of the injection molding machine 2, and detect various physical quantities necessary for controlling the molding operation. Examples of the detected physical quantities include the motor current, voltage, torque, position, speed, and acceleration of the drive unit, the temperature of the injection cylinder 426, the pressure of the resin in the injection cylinder 426, the flow rate of the resin, the temperature and pressure of the mold, the temperature and pressure of the mold temperature regulator, the position and speed of the molded product removal device, and vibrations and sounds generated in each part of the injection molding machine 2. The detected physical quantities are transmitted and output to the control device 1. The control device 1 stores the detected physical quantities in the RAM 13, non-volatile memory 14, etc.

[0021] 4 is a schematic block diagram illustrating functions of the control device 1 according to the first embodiment of the present disclosure. Each function of the control device 1 according to this embodiment is realized by the CPU 11 of the control device 1 shown in FIG. 1 executing a system program and controlling the operation of each part of the control device 1.

[0022] The control device 1 of this embodiment includes a control unit 100, an excitation signal generation unit 110, a data acquisition unit 120, a frequency characteristic calculation unit 130, and an output unit 140. A control program 200 including commands for controlling the injection molding machine 2 is pre-stored in the RAM 13 to the non-volatile memory 14 of the control device 1. Furthermore, the RAM 13 to the non-volatile memory 14 of the control device 1 are pre-stored with a parameter storage unit 210, which is an area in which parameters related to the diagnostic operation of the injection molding machine 2 are pre-stored, and an acquired data storage unit 220, which is an area in which the data acquisition unit 120 stores data acquired from the servo motor 50, sensors, etc., provided in the injection molding machine 2.

[0023] The control unit 100 analyzes the blocks of the control program 200 and controls each part of the injection molding machine 2 based on the analysis results. For example, when a block of the control program 200 commands the control unit 100 to drive each axis of the injection molding machine 2, the control unit 100 generates movement command data in accordance with the command from the block and outputs the movement command data to the servo motor 50 provided in the injection molding machine 2. Furthermore, when a block of the control program 200 commands the control unit 100 to operate a peripheral device attached to the injection molding machine 2, the control unit 100 generates and outputs a predetermined signal to operate the peripheral device. In addition, the control unit 100 can output general commands related to the control of the injection molding machine 2, such as the operation of injecting resin measured in the injection cylinder 426 into a mold, to the injection molding machine 2 in accordance with the command from the block of the control program 200. On the other hand, the control unit 100 acquires position feedback, speed feedback, and torque feedback of the servo motor 50 equipped in the injection molding machine 2, as well as detection value data detected by sensors such as temperature sensors and humidity sensors, and uses this data to control the injection molding machine 2.

[0024] When the control program 200 issues a command to execute a diagnostic operation for the injection molding machine 2, the control unit 100 controls the injection molding machine 2 to perform a diagnostic operation (frequency sweep operation) by moving the servo motor 50 to a diagnostic start position for the diagnostic operation and driving the servo motor 50, which drives the belt 420, at a predetermined range of rotation speeds (frequencies) using a vibration signal generated by the vibration signal generation unit 110. The parameters required for the diagnostic operation (e.g., the diagnostic operation range of the servo motor 50, the upper limit position of the diagnostic operation range, the lower limit position of the diagnostic operation range, the type of vibration signal, the maximum value, minimum value, and increment value of the vibration frequency, etc.) are determined in advance by an operator or manufacturer through experiments or the like and stored in the parameter storage unit 210. The control unit 100 commands the vibration signal generation unit 110 to generate a vibration signal based on the parameters read from the parameter storage unit 210, and the resulting vibration signal is used for the diagnostic operation of the injection molding machine 2.

[0025] The excitation signal generating unit 110 generates an excitation signal that vibrates the servo motor 50 provided in the injection molding machine 2 when performing a diagnostic operation of the injection molding machine 2. The excitation signal may be, for example, a sine wave signal, a square wave signal, a rectangular wave signal, a triangular wave signal, a sawtooth wave signal, or the like.

[0026] FIG. 5 is a graph illustrating changes in the position of the servo motor 50 during a diagnostic operation of the injection molding machine 2. In the example of FIG. 5, a sine wave signal is used as the excitation signal to control the diagnostic operation of the injection molding machine 2. As shown in FIG. 5, when performing a diagnostic operation using a sine wave signal, a sine wave signal with a predetermined amplitude is swept and input to the servo motor 50 as a control signal. For example, the amplitude of the sine wave signal input to the servo motor 50 is kept constant, and the frequency of the sine wave signal is changed over time by increasing the frequency of the sine wave in 10 Hz increments within a range from 1 Hz to 1 kHz. By analyzing the frequency characteristics of the output signal fed back from the servo motor 50 during this diagnostic operation, the operating characteristics of the servo motor 50 can be determined. During the diagnostic operation, the control unit 100 drives the servo motor 50 to move back and forth within a predetermined diagnostic operation range determined by the signal shape and amplitude. In the example of Figure 5, between times td1 and td2 when the diagnostic operation is being performed, the position of the servo motor 50 fluctuates between the upper limit position xd1 of the diagnostic operation and the lower limit position xd2 of the diagnostic operation, with the central position xd0 of the diagnostic operation as the center.

[0027] The control unit 100 according to this embodiment controls the injection molding machine 2 to perform a preliminary operation related to the diagnostic operation before controlling the diagnostic operation of the injection molding machine 2. The preliminary operation related to the diagnostic operation moves the servo motor 50 within a predetermined preliminary operation range. This preliminary operation may be performed by moving the servo motor 50 through all positions within the preliminary operation range. For example, the servo motor 50 may be positioned at one end of the preliminary operation range and then moved to the other end of the preliminary operation range. It is preferable that the preliminary operation range be defined to include the diagnostic operation range in which the servo motor 50 of the injection molding machine 2 is driven during the diagnostic operation, but it may also be a range narrower than the diagnostic operation range. The preliminary operation may be performed at least once, or may be performed by moving back and forth between one end and the other end of the preliminary operation range a predetermined number of times. It is desirable that the preliminary operation related to the diagnostic operation performed for the same injection molding machine 2 always be the same operation. For example, if the first end to be positioned in the preliminary operation for the diagnostic operation of a certain injection molding machine 2 is set to the upper limit position of the preliminary operation range, it is desirable that the first end to be positioned in the preliminary operation range be always set to the upper limit position of the preliminary operation range in subsequent preliminary operations. Also, if positioning is performed once from one end to the other, it is desirable that subsequent preliminary operations also be performed once from one end to the other. This is to ensure that the meshing of the transmission parts and the meshing error (backlash) are consistent each time they are measured when starting the diagnostic operation. This enables stable measurement of frequency characteristics and good reproducibility of the measurement results to be obtained in diagnostic operations performed on the same injection molding machine 2.

[0028] FIG. 6 is a graph illustrating the position change of the servo motor 50 during the preliminary operation for the diagnostic operation. As shown in FIG. 6 , when the preliminary operation for the diagnostic operation is performed, the servo motor 50 is moved from one end to the other end of a preliminary operation range (range between the preliminary operation upper limit position xp1 and the preliminary operation lower limit position xp2), which includes the diagnostic operation range (range between the diagnostic operation upper limit position xd1 and the diagnostic operation lower limit position xd2), within which the servo motor 50 is driven during the diagnostic operation. In the example of FIG. 6 , before the diagnostic operation performed between times td1 and td2 is started, the servo motor 50 is positioned from the preliminary operation start position xp0 to the upper limit position xp1 (> the diagnostic operation upper limit position xd1), which is one end of the preliminary operation range, and then to the lower limit position xp2 (< the diagnostic operation lower limit position xd2), which is the other end of the preliminary operation range. The diagnostic operation is then started after being positioned at the diagnostic start position (center position xd0) of the diagnostic operation.

[0029] FIG. 7 is a graph illustrating an example of positional changes of the servo motor 50 during a preliminary operation for another diagnostic operation. In the preliminary operation for the diagnostic operation illustrated in FIG. 7 , the servo motor 50 is positioned twice, first at the lower limit position xp2, which is one end of the preliminary operation range, and then at the upper limit position xp1, which is the other end. This allows a lubricant such as grease to permeate the power transmission means driven by the servo motor 50, and allows the meshing of the power transmission means, such as a belt, pulley, or gear, to become more even. In the example of FIG. 7 , after positioning the servo motor 50 at the upper limit position xp1 and the lower limit position xp2 of the preliminary operation, the servo motor 50 is put on hold for a predetermined waiting time tw1. This reduces shocks that may occur when the servo motor 50 reverses its rotation. The timing for starting the diagnostic operation after the preliminary operation may be set to a predetermined time tw2. This reduces shocks to the servo motor 50 when transitioning from the preliminary operation to the diagnostic operation. The values ​​of the predetermined waiting time tw1 and the predetermined time tw2 may be selected, for example, by repeatedly conducting an experiment in which the rotation direction of the servo motor 50 is reversed and shocks are observed.

[0030] The upper limit position xp1 and the lower limit position xp2 of the preliminary operation may be determined depending on the structure of the power transmission means. For example, when a toothed belt and toothed pulley as shown in FIG. 8 are used as the power transmission means, the upper limit position xp1 and the lower limit position xp2 of the preliminary operation may be determined to be the distance from the center position xd0 of the diagnostic operation obtained by multiplying the pitch p of the toothed belt or toothed pulley by a predetermined coefficient α (α is 1.0 or greater). Even when the power transmission means is a chain, nut, ball screw (ball spline), etc., the upper limit position xp1 and the lower limit position xp2 of the preliminary operation may be determined based on the pitch of each. By determining the positions in this manner, the meshing state (backlash, gap, play, rattle) of the power transmission components of the drive unit, such as the belt, pulley, and gear, is always the same at the start of the diagnostic operation. Therefore, the analysis results of the diagnostic operation can be expected to be stable.

[0031] The upper limit position xp1 of the preliminary operation may be determined by adding a predetermined margin value β1 (β1 is 0.0 or greater) to the upper limit position xd1 of the diagnostic operation. The lower limit position xp2 of the preliminary operation may be determined by subtracting a predetermined margin value β2 (β2 is 0.0 or greater) from the lower limit position xd2 of the diagnostic operation. The preliminary operation range may be determined to be the width of the diagnostic operation range multiplied by a predetermined coefficient γ (γ is 1.0 or greater). For example, in the case of a diagnostic operation using a sine wave signal as illustrated in Figures 5 and 6, the upper limit position xp1 and the lower limit position xp2 of the preliminary operation may be determined at a distance from the center position in the amplitude direction of the sine wave by a predetermined coefficient γ multiplied by the amplitude of the sine wave. By defining the preliminary operation range in this manner, the preliminary operation range includes the diagnostic operation range, and the lubrication condition (grease) of the drive parts within the diagnostic operation range is always consistent at the start of the diagnostic operation. This allows for stable analysis results of the diagnostic operation to be expected.

[0032] If the upper limit position xp1 and the lower limit position xp2 of the preliminary operation determined by the above method are outside the movable range of the servo motor 50, they may be clamped so that they are within the movable range of the servo motor 50.

[0033] When controlling the positioning of the preliminary operation, the control unit 100 may set a predetermined torque limit value for the torque of the servo motor 50. This torque limit value is preferably smaller than the torque limit value during normal operation when the injection molding machine 2 manufactures molded products. The torque limit value may be smaller than the torque limit value during normal operation and during diagnostic operation of the injection molding machine 2. Also, a predetermined speed limit value may be set for the speed of the servo motor 50. This speed limit value is preferably smaller than the speed limit value during normal operation of the injection molding machine 2. The speed limit value may be smaller than the speed limit value during normal operation and during diagnostic operation of the injection molding machine 2. In this way, by limiting the movement during positioning of the preliminary operation to a lower torque or speed than during normal operation, it is possible to safely position the servo motor 50 to the diagnosis start position.

[0034] The control unit 100 may be configured to stop the pre-operation and diagnostic operation if the elapsed time from the start of the pre-operation to its completion exceeds a predetermined time limit. In such a case, the control unit 100 may output a warning, such as by displaying an alarm message on the display device 70 or sounding a buzzer. If the pre-operation takes longer than expected, there is a high possibility that some kind of trouble has occurred in the drive unit. Starting a diagnostic operation in such a state not only makes it impossible to perform an accurate diagnosis, but also may cause serious damage to the drive unit of the injection molding machine 2. Detecting such a situation can prevent problems from occurring in advance.

[0035] Parameters related to the pre-operation (pre-operation range, upper limit position of the pre-operation, lower limit position of the pre-operation, positioning sequence, number of positioning operations, torque limit value, speed limit value, torque during positioning, speed during positioning, etc.) can be determined in advance by an operator or manufacturer based on experiments and stored in the parameter memory unit 210.

[0036] The data acquisition unit 120 acquires feedback data such as position feedback, velocity feedback, and torque feedback from the servo motor 50 of the injection molding machine 2 during the diagnostic operation of the injection molding machine 2, as well as detection value data detected by sensors and the like of the injection molding machine 2, and stores the acquired data in the acquired data storage unit 220. The feedback data such as position feedback, velocity feedback, and torque feedback acquired by the data acquisition unit 120 is time-series data. The detection value data acquired by the data acquisition unit 120 may be data values ​​acquired at a predetermined timing. For example, the room temperature at the timing when the diagnostic operation is started may be acquired as the detection value data. The data acquisition unit 120 may also acquire data detected by another industrial machine 4 from the industrial machine 4 via the network 5. Furthermore, the data acquisition unit 120 may also acquire data input by an operator via the input device 71 or data input via an external device 72.

[0037] During the diagnostic operation of the injection molding machine 2, the frequency characteristic calculation unit 130 calculates frequency response data (hereinafter referred to as a resonance curve) that indicates the frequency characteristics of feedback data such as position feedback, velocity feedback, and torque feedback acquired by the data acquisition unit 120. The resonance curve calculated by the frequency characteristic calculation unit 130 may be, for example, a gain curve that is curve data that indicates frequency-gain characteristics, or a phase curve that is curve data that indicates frequency-phase characteristics. Such data can be calculated by performing known frequency analysis such as fast Fourier transform on the feedback data that is time-series data.

[0038] The output unit 140 outputs and displays on the display device 70 a resonance curve indicating the frequency characteristics of the feedback data during the diagnostic operation calculated by the frequency characteristic calculation unit 130. The output unit 140 may transmit and output the determination result of the resonance curve to the injection molding machine 2 via the network 5. Alternatively, the output unit 140 may transmit and output the result to a higher-level computer such as the fog computer 6 or the cloud server 7. Furthermore, the output may be output to a log recording area provided in advance on the non-volatile memory 14 or the like. The output resonance curve indicating the frequency characteristics is used to analyze the resonance point, stability, responsiveness, etc. of the drive unit of the injection molding machine 2 driven by the servo motor 50, and to understand the operating characteristics.

[0039] The control device 1 according to this embodiment, having the above configuration, moves the drive unit within a predetermined pre-operation range (between the upper and lower pre-operation positions) before performing a diagnostic operation. By always performing the same pre-operation before performing a diagnostic operation, the motor rotation direction and the movement direction of the movable parts of the drive unit are always the same when positioning the drive unit to its position at the start of the diagnosis. Therefore, the meshing state (backlash, clearance, play, and rattle) of the power transmission parts, such as the belt, pulley, and gears, of the drive unit are always the same when the diagnostic operation is initiated. This ensures that the diagnostic operation is performed under the same conditions, thereby achieving reproducibility of the diagnostic operation. Furthermore, the reproducibility of the analysis results of the frequency characteristics obtained from the diagnostic operation is also improved. For example, the reproducibility, analysis accuracy, and reliability of the analysis results, such as the graph shape of the resonance curve obtained by analyzing the frequency characteristics and the resonance point (resonance frequency) obtained by analyzing the resonance curve, are improved.

[0040] Furthermore, by setting the preliminary operating range to include the diagnostic operating range, the lubrication state of the lubricant (grease) on the moving parts of the drive unit becomes stable, and the friction force on the moving parts of the drive unit during the diagnostic operation becomes the same when the diagnostic operation is performed, thereby achieving reproducibility of the diagnostic operation.

[0041] [Second Embodiment] A control device 1 according to a second embodiment will be described below. The control device 1 according to this embodiment differs from the control device 1 according to the first embodiment in that it has a function of supporting parameter setting for a preliminary operation. The control device 1 according to the second embodiment has the same hardware configuration as the control device according to the first embodiment.

[0042] 9 is a schematic block diagram showing functions of the control device 1 according to the second embodiment. Each function of the control device 1 according to this embodiment is realized by the CPU 11 of the control device 1 shown in FIG. 1 executing a system program and controlling the operation of each part of the control device 1.

[0043] The control device 1 of this embodiment includes a parameter setting unit 150 in addition to a control unit 100, an excitation signal generating unit 110, a data acquiring unit 120, a frequency characteristic calculating unit 130, and an output unit 140. A control program 200 including commands for controlling the injection molding machine 2 is pre-stored in the RAM 13 to the non-volatile memory 14 of the control device 1. The RAM 13 to the non-volatile memory 14 of the control device 1 also include a parameter storage unit 210, which is an area in which parameters related to the diagnostic operation of the injection molding machine 2 are pre-stored, and an acquired data storage unit 220, which is an area in which the data acquiring unit 120 stores data acquired from the servo motor 50, sensors, etc., of the injection molding machine 2.

[0044] The control unit 100, the vibration signal generation unit 110, the data acquisition unit 120, the frequency characteristic calculation unit 130, and the output unit 140 provided in the control device 1 according to this embodiment have the same functions as the control unit 100, the vibration signal generation unit 110, the data acquisition unit 120, the frequency characteristic calculation unit 130, and the output unit 140 provided in the control device 1 according to the first embodiment.

[0045] The parameter setting unit 150 according to this embodiment provides a user interface for the operator to set parameters related to the preliminary operation range. FIG. 10 is a screen configuration diagram illustrating an example of a preliminary operation range setting screen. In the example of FIG. 10, a user interface is provided for calculating the upper and lower limit positions of the preliminary operation based on the configuration of the power transmission means and the parameters of the diagnostic operation range. The configuration of the power transmission means (e.g., pitch value) may be set in advance in the control device 1 as a parameter related to the configuration of the injection molding machine 2. Furthermore, the parameters related to the diagnostic operation range may be read and used from values ​​previously set in the parameter storage unit 210. The preliminary operation range setting screen may display a graph showing position changes related to the diagnostic operation on the screen based on the parameter values ​​set in the parameter storage unit 210. The operator may input the upper and lower limit positions of the preliminary operation while referring to the screen. Furthermore, the upper and lower limit positions of the preliminary operation may be calculated according to the configuration of the power transmission means by inputting a coefficient α related to the toothed belt of the power transmission means. For example, the upper and lower limit positions of the preliminary operation may be calculated by multiplying the pitch of the toothed belt by the coefficient α. Furthermore, by inputting coefficients β1, β2, γ, etc. related to the diagnostic operation range, the upper limit position and the lower limit position of the pre-operation may be calculated according to the diagnostic operation range. For example, the upper limit position of the pre-operation may be calculated by adding the coefficient β1 to the upper limit position of the diagnostic operation range. The setting screen for the pre-operation range may display a graph related to position changes related to the pre-operation on the screen based on the input upper limit position and lower limit position of the pre-operation and the values ​​of the parameters related to the pre-operation set in the parameter storage unit 210.

[0046] The control device 1 according to this embodiment having the above configuration can appropriately determine the upper limit position and the lower limit position of the preliminary operation, thereby eliminating the need for the operator to carry out trial and error.

[0047] The control device 1 according to each embodiment of the present disclosure described so far performs a preliminary operation before performing a diagnostic operation, so that the meshing state (backlash, gap, play, rattle) of power transmission parts such as belts, pulleys, and gears of the drive unit is always in the same state when the diagnostic operation is started. As a result, the diagnostic operation is performed in the same state, so the reproducibility of the diagnostic operation is achieved, and the reproducibility of the analysis results (frequency characteristics) obtained from the diagnostic operation is also good.

[0048] The above-described embodiments of the present disclosure describe the operation of the control device 1 using an injection molding machine 2 as an example of an industrial machine. However, the control device 1 according to the present disclosure can be applied to various other industrial machines. For example, the control device 1 can be suitably used to diagnose the operation of industrial machines equipped with a predetermined prime mover and power transmission means, such as extruders, blow molding machines, electric discharge machines, robots, machine tools, and mining machines. Examples of prime movers equipped in industrial machines include servo motors, hydraulic motors, hydraulic cylinders, linear motors, and direct drive motors. Examples of power transmission means equipped in industrial machines include drives equipped with any of belts, pulleys, linear bushings, ball screws, splined components, and the like.

[0049] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the invention or the idea and intent of the present disclosure derived from the content described in the claims and their equivalents. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0050] The following are supplementary notes related to embodiments of the present disclosure. (Supplementary Note 1) A control device (1) according to one aspect of the present disclosure includes: a vibration signal generation unit (110) that generates a vibration signal that vibrates a prime mover (50) that drives a drive unit included in an industrial machine (4); a control unit (100) that positions the prime mover (50) at a predetermined diagnosis start position and controls a diagnostic operation that diagnoses frequency characteristics using the vibration signal; a data acquisition unit (120) that acquires at least the vibration signal and feedback data obtained from the diagnostic operation; and a frequency characteristic calculation unit (130) that calculates a resonance curve that indicates frequency characteristics based on the feedback data, wherein, before performing control related to the diagnostic operation, the control unit (100) controls a pre-operation that performs at least one operation of positioning the prime mover (50) at one end of a predetermined pre-operation range and then positioning it at the other end of the pre-operation range, and then positions the prime mover (50) at the diagnosis start position and starts the diagnostic operation.

[0051] (Supplementary Note 2) In the control device (1) according to another aspect of the present disclosure, the torque limit value when the control unit (100) executes the preliminary operation is a value smaller than either the torque limit value when the industrial machine (4) is normally operated or the torque limit value when the diagnostic operation is controlled. (Supplementary Note 3) In the control device (1) according to another aspect of the present disclosure, the speed limit value when the control unit (100) executes the preliminary operation is a value smaller than either the speed limit value when the industrial machine (4) is normally operated or the speed limit value when the diagnostic operation is controlled.

[0052] (Supplementary Note 4) In the control device (1) according to another aspect of the present disclosure, the pre-operating range includes the range of the diagnostic operation. (Supplementary Note 5) In the control device (1) according to another aspect of the present disclosure, the power transmission means of the drive unit includes at least one of a toothed belt and a gear, and the pre-operating range is determined based on either the pitch of adjacent teeth of the toothed belt or the pitch of adjacent teeth of the gear.

[0053] (Supplementary Note 6) The control device (1) according to another aspect of the present disclosure further includes a parameter setting unit (150) that provides a user interface for an operator to specify the preliminary operating range.

[0054] (Supplementary Note 7) In the control device (1) according to another aspect of the present disclosure, when the control unit (100) positions the prime mover (50) at at least one of one end and the other end of the preliminary operation, the control unit (100) waits for a predetermined waiting time. (Supplementary Note 8) In the control device (1) according to another aspect of the present disclosure, the preliminary operation performs an operation of positioning the prime mover at one end of the preliminary operation range and then at the other end of the preliminary operation range two or more times.

[0055] (Supplementary Note 9) In a control device (1) according to another aspect of the present disclosure, the control unit (100) clamps the preliminary operating range to the movable range of the prime mover (50) when the preliminary operating range is outside the movable range of the prime mover (50). (Supplementary Note 10) In a control device (1) according to another aspect of the present disclosure, the control unit (100) halts the start of the diagnostic operation when the elapsed time required for the preliminary operation exceeds a predetermined time limit. (Supplementary Note 11) The control device (1) according to another aspect of the present disclosure further includes a display device (70), and displays and outputs the results of the diagnostic operation on the display device (70).

[0056] (Supplementary Note 12) A control method according to one aspect of the present disclosure includes a control device (1) executing a vibration signal generation step in which a control device (1) generates a vibration signal that vibrates a prime mover (50) that drives a drive unit provided in an industrial machine (4); a preliminary operation step in which a preliminary operation is controlled to perform at least one operation of positioning the prime mover (50) at one end of a predetermined preliminary operation range and then positioning it at the other end of the preliminary operation range; a diagnostic operation step in which the control device (1) positions the prime mover (50) at a predetermined diagnosis start position and controls a diagnostic operation that diagnoses frequency characteristics using the vibration signal; a data acquisition step in which the control device (1) acquires at least the vibration signal and feedback data obtained from the diagnostic operation; and a frequency characteristic calculation step in which a resonance curve indicating frequency characteristics is calculated based on the feedback data.

[0057] REFERENCE SIGNS LIST 1 Control device 2 Injection molding machine 4 Industrial machine 5 Network 6 Fog computer 7 Cloud server 11 CPU 12 ROM 13 RAM 14 Non-volatile memory 15, 17, 18, 20 Interface 22 Bus 50 Servo motor 70 Display device 71 Input device 72 External device 100 Control unit 110 Vibration signal generation unit 120 Data acquisition unit 130 Frequency characteristic calculation unit 140 Output unit 150 Parameter setting unit 200 Control program 210 Parameter storage unit 220 Acquired data storage unit 420 Belt 422 Pulley

Claims

1. a vibration signal generating unit that generates a vibration signal that vibrates a prime mover that drives a drive unit included in the industrial machine; a control unit that positions the motor at a predetermined diagnosis start position and controls a diagnostic operation that diagnoses frequency characteristics using the excitation signal; a data acquisition unit that acquires at least the excitation signal and feedback data obtained from the diagnostic operation; a frequency characteristic calculation unit that calculates a resonance curve indicating a frequency characteristic based on the feedback data; Equipped with the control unit controls a preliminary operation of performing at least one operation of positioning the prime mover to one end of a predetermined preliminary operating range and then positioning the prime mover to the other end of the preliminary operating range before performing control related to the diagnostic operation, and then positions the prime mover at the diagnosis start position and starts the diagnostic operation. Control device.

2. a torque limit value when the control unit executes the preliminary operation is smaller than either a torque limit value when the industrial machine is normally operated or a torque limit value when the control unit controls the diagnostic operation; The control device according to claim 1 .

3. a speed limit value when the control unit executes the preliminary operation is smaller than either a speed limit value when the industrial machine is normally operated or a speed limit value when the control unit controls the diagnostic operation. The control device according to claim 1 .

4. the preliminary operating range includes the diagnostic operating range; The control device according to claim 1 .

5. the power transmission means of the drive unit includes at least one of a toothed belt and a gear; The pre-operating range is determined based on either a pitch of adjacent teeth of the toothed belt or a pitch of adjacent teeth of the gear. The control device according to claim 1 .

6. a parameter setting unit that provides a user interface for an operator to specify the preliminary operating range; The control device according to claim 1 .

7. the control unit waits for a predetermined waiting time when the prime mover is positioned at least at one end or the other end of the preliminary operation. The control device according to claim 1 .

8. the preliminary operation includes performing an operation of positioning the prime mover to one end of the preliminary operation range and then positioning the prime mover to the other end of the preliminary operation range two or more times; The control device according to claim 1 .

9. When the preliminary operating range is outside the movable range of the prime mover, the control unit clamps the preliminary operating range to the movable range. The control device according to claim 1 .

10. the control unit cancels the start of the diagnostic operation when the elapsed time required for the preliminary operation exceeds a predetermined time limit. The control device according to claim 1 .

11. a display device; outputting and displaying the results of the diagnostic operation on the display device; The control device according to claim 1 .

12. The control device a vibration signal generating step of generating a vibration signal for vibrating a prime mover that drives a drive unit included in the industrial machine; a pre-operation step of controlling a pre-operation in which the prime mover is positioned at one end of a predetermined pre-operation range and then positioned at the other end of the pre-operation range at least once; a diagnostic operation step of positioning the prime mover at a predetermined diagnostic start position and controlling a diagnostic operation for diagnosing frequency characteristics using the excitation signal; a data acquisition step of acquiring at least the excitation signal and feedback data obtained from the diagnostic operation; a frequency characteristic calculation step of calculating a resonance curve indicating frequency characteristics based on the feedback data; A control method for performing