WO2023042494A1 - 寿命推定方法、寿命推定装置及びコンピュータプログラム - Google Patents
寿命推定方法、寿命推定装置及びコンピュータプログラム Download PDFInfo
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- WO2023042494A1 WO2023042494A1 PCT/JP2022/022706 JP2022022706W WO2023042494A1 WO 2023042494 A1 WO2023042494 A1 WO 2023042494A1 JP 2022022706 W JP2022022706 W JP 2022022706W WO 2023042494 A1 WO2023042494 A1 WO 2023042494A1
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- 238000000034 method Methods 0.000 title claims description 43
- 238000004590 computer program Methods 0.000 title claims description 12
- 230000008859 change Effects 0.000 claims abstract description 22
- 230000002596 correlated effect Effects 0.000 claims abstract description 12
- 230000001133 acceleration Effects 0.000 claims description 66
- 230000008569 process Effects 0.000 claims description 13
- 238000004364 calculation method Methods 0.000 claims description 10
- 230000002123 temporal effect Effects 0.000 claims description 9
- 238000000465 moulding Methods 0.000 claims description 7
- 238000007476 Maximum Likelihood Methods 0.000 claims description 5
- 230000015556 catabolic process Effects 0.000 abstract 2
- 230000006870 function Effects 0.000 description 53
- 238000001746 injection moulding Methods 0.000 description 30
- 238000002347 injection Methods 0.000 description 28
- 239000007924 injection Substances 0.000 description 28
- 238000012545 processing Methods 0.000 description 17
- 238000010586 diagram Methods 0.000 description 11
- 238000010438 heat treatment Methods 0.000 description 10
- 230000007246 mechanism Effects 0.000 description 8
- 230000000875 corresponding effect Effects 0.000 description 4
- 238000010801 machine learning Methods 0.000 description 4
- 239000012778 molding material Substances 0.000 description 4
- 238000013528 artificial neural network Methods 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 238000012706 support-vector machine Methods 0.000 description 2
- 238000012549 training Methods 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001537 neural effect Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/76—Measuring, controlling or regulating
Definitions
- the present invention relates to a lifespan estimation method, a lifespan estimation device, and a computer program.
- the injection molding machine is equipped with an injection device that melts and injects the molding material and a mold clamping device.
- the injection device includes a heating cylinder having a nozzle at its tip, and a screw arranged in the heating cylinder so as to be rotatable in the circumferential direction and the axial direction.
- the screw is driven rotationally and axially by a drive mechanism.
- the drive mechanism includes a ball screw that converts the rotational drive force of the injection servomotor into the drive force in the axial direction of the screw and transmits the force (for example, Patent Document 1).
- An object of the present invention is to provide a life estimation method, a life estimation device, and a computer program capable of accumulating physical quantity data indicating the state of a predetermined portion of an industrial machine and calculating the failure time or failure probability of the predetermined portion. That's what it is.
- a lifespan estimation method acquires physical quantity data indicating the state of a predetermined part constituting an industrial machine, and stores the acquired physical quantity data and time data indicating the acquisition time of the physical quantity data in association with each other. Then, based on the obtained physical quantity data and the time data, a function for estimating a change over time in a parameter value that is correlated with the life of the predetermined part is calculated, and the calculated function is used to determine the value of the predetermined part. Calculate failure time or failure probability.
- a lifespan estimation device corresponds to an acquisition unit that acquires physical quantity data indicating the state of a predetermined part that constitutes an industrial machine, and the acquired physical quantity data and time data that indicates when the physical quantity data was acquired. a function for estimating the change over time of a parameter value correlated with the lifetime of the predetermined portion based on the storage unit to be stored with the data and the acquired physical quantity data and the time data, and calculating the calculated function and a calculation unit for calculating a failure time or a failure probability of the predetermined part using the above.
- a computer program acquires physical quantity data indicating a state of a predetermined part that constitutes an industrial machine, and stores the acquired physical quantity data and time data indicating acquisition time of the physical quantity data in association with each other. , based on the obtained physical quantity data and the time data, calculating a function for estimating a change over time of a parameter value correlated with the life of the predetermined part, and using the calculated function, the failure of the predetermined part A computer is caused to execute processing for calculating the timing or failure probability.
- FIG. 1 is a schematic diagram showing a configuration example of an injection molding machine according to Embodiment 1.
- FIG. FIG. 2 is a cross-sectional view showing a configuration example of a driving device of the injection molding machine according to Embodiment 1;
- 4 is a flow chart showing a processing procedure of a computing unit according to the first embodiment;
- FIG. 4 is an explanatory diagram showing a method of calculating a function for estimating changes over time in vibration acceleration peak values that are correlated with the service life of a ball screw;
- FIG. 4 is an explanatory diagram showing a method of calculating the failure probability of the life of a ball screw and the failure time;
- FIG. 4 is an explanatory diagram showing a method of calculating the failure probability of the life of a ball screw and the failure time;
- FIG. 4 is an explanatory diagram showing a method of calculating the failure probability of the life of a ball screw and the failure time;
- FIG. 11 is a schematic diagram showing an example of a display screen for an estimation result
- 9 is a flow chart showing a processing procedure of a computing unit according to the second embodiment
- FIG. 11 is a schematic diagram showing a configuration example of a control device according to Embodiment 3;
- FIG. 1 is a schematic diagram showing a configuration example of an injection molding machine 1 according to Embodiment 1.
- An injection molding machine 1 according to the first embodiment includes a mold clamping device 2 that clamps a mold 21 , an injection device 3 that melts and injects a molding material, and a control device 4 .
- the control device 4 functions as a life estimation device according to the first embodiment.
- the mold clamping device 2 includes a fixed platen 22 fixed on the bed 20, a mold clamping housing 23 slidably provided on the bed 20, and a movable platen 24 that slides on the bed 20 as well.
- the stationary platen 22 and the mold clamping housing 23 are connected by a plurality of tie bars 25, 25, . . .
- the movable platen 24 is configured to be slidable between the fixed platen 22 and the mold clamping housing 23 .
- a mold clamping mechanism 26 is provided between the mold clamping housing 23 and the movable platen 24 .
- the mold clamping mechanism 26 is composed of, for example, a toggle mechanism.
- the mold clamping mechanism 26 may be configured by a direct pressure type mold clamping mechanism, that is, a mold clamping cylinder.
- a fixed mold 28 and a movable mold 27 are provided on the fixed platen 22 and the movable platen 24, respectively. When the mold clamping mechanism 26 is driven, the mold 21 is opened and closed.
- the injection device 3 is provided on the base 30.
- the injection device 3 includes a heating cylinder 31 having a nozzle 31a at its tip, and a screw 32 arranged in the heating cylinder 31 so as to be rotatable in the circumferential and axial directions.
- a heater for melting the molding material is provided inside or on the outer periphery of the heating cylinder 31 .
- the screw 32 is driven rotationally and axially by the driving device 5 .
- a hopper 33 into which molding material is charged is provided near the rear end of the heating cylinder 31 .
- the injection molding machine 1 also includes a nozzle touch device 34 for moving the injection device 3 in the front-rear direction (left-right direction in FIG. 1). When the nozzle touch device 34 is driven, the injection device 3 advances and the nozzle 31 a of the heating cylinder 31 touches the contact portion of the stationary platen 22 .
- the control device 4 is a computer that controls the operations of the mold clamping device 2 and the injection device 3, and includes a processor (calculation unit) 41, a storage unit 42, an operation unit 43, an acquisition unit 44, a display unit 45, etc. as a hardware configuration.
- the control device 4 may be a server device connected to a network.
- the control device 4 may be configured with a plurality of computers to perform distributed processing, may be realized by a plurality of virtual machines provided in one server, or may be realized using a cloud server. may have been
- the processor 41 includes a CPU (Central Processing Unit), a multi-core CPU, a GPU (Graphics Processing Unit), a GPGPU (General-purpose computing on graphics processing units), a TPU (Tensor Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA ( Field-Programmable Gate Array), arithmetic circuits such as NPU (Neural Processing Unit), internal storage devices such as ROM (Read Only Memory) and RAM (Random Access Memory), I/O terminals, timers, etc.
- the processor 41 implements the control method according to the first embodiment by executing a computer program (program product) 42a stored in a storage unit 42, which will be described later.
- the storage unit 42 is a non-volatile memory such as a hard disk, EEPROM (Electrically Erasable Programmable ROM), and flash memory.
- the storage unit 42 stores a computer program 42a for causing a computer to execute processing for calculating the failure time and failure probability of the ball screw 51 .
- the computer program 42a according to the first embodiment may be recorded on the recording medium 6 in a computer-readable manner.
- the storage unit 42 stores a computer program 42a read from the recording medium 6 by the reading device.
- a recording medium 6 is a semiconductor memory such as a flash memory.
- the recording medium 6 may be an optical disc such as a CD (Compact Disc)-ROM, a DVD (Digital Versatile Disc)-ROM, or a BD (Blu-ray (registered trademark) Disc).
- the recording medium 6 may be a magnetic disk such as a flexible disk or a hard disk, or a magneto-optical disk.
- the computer program 42a according to the first embodiment may be downloaded from an external server connected to a communication network and stored in the storage unit 42. FIG.
- the operation unit 43 is an input device such as a touch panel, soft keys, hard keys, keyboard, and mouse.
- the acquisition unit 44 AD-converts a rotation angle signal output from an encoder 50d, which will be described later, and an acceleration signal output from the acceleration sensor 5a, and acquires rotation angle data and acceleration data.
- the display unit 45 is a liquid crystal panel, organic EL display, electronic paper, plasma display, or the like. The display unit 45 displays various information according to the image data given from the processor 41 .
- the injection molding machine 1 has set values that define molding conditions such as injection start time, mold resin temperature, nozzle temperature, cylinder temperature, hopper temperature, mold clamping force, injection speed, injection acceleration, injection peak pressure, injection stroke, etc. is set.
- the injection molding machine 1 has information such as resin pressure at the tip of the cylinder, check ring seating state, holding pressure switching pressure, holding pressure switching speed, holding pressure switching position, holding pressure completion position, cushion position, metering back pressure, metering torque, and the like.
- Set values are set to define molding conditions.
- setting values are set which determine molding conditions such as a metering completion position, a screw 32 retreat speed, a cycle time, a mold closing time, an injection time, a pressure holding time, a metering time, and a mold opening time.
- the injection molding machine 1 in which these set values are set operates according to the set values.
- FIG. 2 is a cross-sectional view showing a configuration example of the driving device 5 of the injection molding machine 1 according to the first embodiment.
- the driving device 5 includes an injection servomotor 50 and a ball screw 51 for axially driving the screw 32 .
- the injection servomotor 50 is provided with an encoder 50 d that detects a rotation angle and outputs a rotation angle signal indicating the rotation angle to the control device 4 .
- the control device 4 controls the rotation of the injection servomotor 50 based on the rotation angle signal output from the encoder 50d.
- the output shaft of the injection servomotor 50 is provided with a small pulley 50a.
- the ball screw 51 includes a ball screw shaft 51a and a nut 51b screwed onto the ball screw shaft 51a.
- a base end of the ball screw shaft 51a is rotatably supported by a first plate 52 having a hole and a bearing seat via a bearing 52a.
- a large pulley 50c is provided at the proximal end of the ball screw shaft 51a.
- the small pulley 50a and the large pulley 50c are connected by a timing belt 50b, and the rotational force of the small pulley 50a is transmitted to the large pulley 50c to rotate the ball screw shaft 51a.
- the direction toward the base end of the ball screw shaft 51a (right side in FIG. 1) is called the backward direction, and the opposite direction (left side in FIG.
- the forward direction is called the forward direction.
- the advancing direction and the retreating direction are collectively referred to as the advancing/retreating direction.
- a load cell 53 is provided on the forward direction side surface of the nut 51 b , and the forward direction side surface of the load cell 53 is fixed to the second plate 54 .
- a plurality of through holes are formed in the second plate 54, and guide shafts 55 are inserted through the through holes.
- the second plate 54 is guided by the guide shaft 55 and moves in the advancing/retreating direction.
- a third plate 56 is provided on the forward direction side of the first plate 52, and one end and the other end of the guide shaft 55 are supported by the first plate 52 and the third plate 56, respectively.
- a hole and a bearing seat are provided in the second plate 54, and an output shaft 58 is supported in the hole via a bearing 54a.
- a plasticizing pulley 57 is provided on the output shaft 58 .
- the plasticizing pulley 57 is connected via a timing belt (not shown) to a pulley attached to a motor for rotating the screw 32 (not shown).
- the center of rotation of the output shaft 58 coincides with the center of rotation of the ball screw shaft 51a.
- the output shaft 58 is formed with a recess into which the tip of the ball screw shaft 51a enters when the nut 51b is moved back and forth. Further, one end of the screw 32 is fixed to the output shaft 58 so that the center axis thereof coincides with the output shaft 58 .
- a through hole through which the screw 32 is inserted is formed in the third plate 56 .
- One end of the heating cylinder 31 is fixed to the third plate 56 so that the screw 32 inserted through the through hole of the third plate 56 can move in the heating cylinder 31 in the axial direction.
- An acceleration sensor 5a is attached to the nut 51b of the ball screw 51 to detect the vibration of the nut 51b.
- the acceleration sensor 5 a outputs the detected acceleration signal to the control device 4 .
- the processor 41 of the control device 4 AD-converts the acceleration signal output from the acceleration sensor 5a into acceleration data in the acquisition unit 44 and acquires the acceleration data.
- the controller 4 can estimate the life of the ball screw 51 based on the acceleration data.
- the outline of the molding process cycle is as follows, and the control device 4 performs processing to sequentially move the forward/backward movement range of the nut 51b in the repeated molding process cycle.
- injection molding a well-known mold closing process, mold clamping process, injection unit advancing process, injection process, weighing process, injection unit retreating process, mold opening process and ejecting process are sequentially performed.
- FIG. 3 is a flow chart showing the processing procedure of the processor 41 according to the first embodiment.
- the processor 41 acquires acceleration data indicating the state of the ball screw 51 from the acceleration sensor 5a via the acquisition unit 44 (step S111).
- the calculation unit associates the acquired acceleration data with the time data indicating the time when the acceleration data was acquired and stores them in the storage unit 42 (step S112).
- Time data is obtained from the timer.
- the calculation unit calculates a first function for estimating the temporal change in the acceleration peak value that is correlated with the service life of the ball screw 51 (step S113 ).
- the acceleration peak value is an example of parameter values that are correlated with the life of the ball screw 51 .
- FIG. 4 is an explanatory diagram showing a method of calculating a function for estimating a change over time in the vibration acceleration peak value that correlates with the service life of the ball screw 51.
- FIG. The horizontal axis of the graph shown in FIG. 4 indicates time, and the vertical axis indicates acceleration peak value.
- the time on the horizontal axis corresponds to the operating time of the ball screw 51, and the acceleration peak value corresponds to the degree of failure of the ball screw 51.
- the processor 41 Based on the acceleration data and time data accumulated in the storage unit 42 over a predetermined period of time, the processor 41 obtains a first function indicating the temporal change of the acceleration peak value by the maximum likelihood estimation method.
- the first function is represented by the following formula.
- P a x e bt + c (1) however, P: acceleration peak value t: time a, b, c: coefficient
- the processor 41 obtains the first function by calculating the coefficients a, b, and c that minimize the mean squared error.
- the processor 41 estimates the change over time of the value obtained by adding the standard deviation (predetermined deviation) of the normal distribution to the acceleration peak value calculated using the first function.
- a second function for is calculated (step S114). Specifically, the processor 41 calculates acceleration peak values (average values) calculated using the first function at a plurality of time points, and acceleration data and time data as sample data stored in the storage unit 42. , to calculate the standard deviation at each of the multiple time points. Then, a value obtained by adding the standard deviation at each time point to the acceleration peak value (average value) at each time point is obtained. Then, the processor 41 calculates a second function indicating the temporal change of the calculated value by the maximum likelihood estimation method. The second function is also expressed using an exponential function as shown in Equation (1) above.
- the processor 41 calculates a third function for estimating the temporal change of the values obtained by subtracting the standard deviation of the normal distribution from the multiple time point meter values (step S115).
- the calculation method of the third function is the same as the calculation method of the second function.
- the processor 41 calculates the failure time and failure probability of the ball screw 51 using the first function (step S116). Similarly, the processor 41 calculates the failure time and failure probability of the ball screw 51 using the second function (step S117). The processor 41 also calculates the failure time and failure probability of the ball screw 51 using the third function (step S118).
- FIG. 5A and 5B are explanatory diagrams showing a method of calculating the life failure probability and failure timing of the ball screw 51.
- the processor 41 determines the point at which the acceleration peak value calculated using the first function reaches a predetermined failure determination threshold as the failure time when the failure probability is 50% (first probability).
- the failure determination threshold value may be stored in the storage unit 42 in advance, or may be configured so that the processor 41 receives it from the operator through the operation unit 43 .
- the processor 41 calculates the point in time when the acceleration peak value calculated using the second function reaches a predetermined failure determination threshold as the failure time when the failure probability is 16% (second probability).
- the processor 41 calculates the point in time when the acceleration peak value calculated using the third function reaches a predetermined failure determination threshold as the failure time when the failure probability is 84% (third probability).
- the processor 41 uses the first function to find the acceleration peak value (average value) at the specific estimated reference time. Then, the processor 41 calculates the variance or standard deviation at the estimated reference time based on the average value of the acceleration peak values and the acceleration data and the time data as samples stored in the storage unit 42, , the probability that the acceleration peak value becomes the failure determination threshold may be calculated. That is, assuming that the acceleration peak value follows a normal distribution at the estimated reference time, the probability that the acceleration peak value becomes the failure determination threshold can be obtained.
- the processor 41 displays the measured value graph 45a and the estimated value graphs 45b, 45c, 45d, etc. on the display unit 45 (step S119), and ends the process.
- FIG. 6 is a schematic diagram showing an example of a display screen for estimation results.
- the processor 41 displays the horizontal axis and the vertical axis of the graph on the display unit 45, and displays the graph lines of the measured value graph 45a and the estimated value graphs 45b, 45c, and 45d.
- the horizontal axis indicates the operating time corresponding to the elapsed time
- the vertical axis indicates the degree of failure corresponding to the acceleration peak value.
- the measured value graph 45a is a graph showing measured values of changes in acceleration peak value over time, based on the acceleration data and time data stored in the storage unit 42 .
- Estimated value graphs 45b, 45c, and 45d are graphs showing temporal changes in acceleration peak values obtained by the first function, the second function, and the third function, respectively.
- the processor 41 also displays a threshold line image 45f indicating the failure determination threshold on the display unit 45.
- FIG. Furthermore, the processor 41 displays a normal distribution image 45e indicating the elapsed time from the present
- the operator of the injection molding machine 1 visually recognizes the current actual state of the ball screw 51, failure time, and failure probability from the measured value graph 45a and the estimated value graphs 45b, 45c, and 45d displayed on the display unit 45. be able to.
- the injection molding machine 1 As described above, according to the injection molding machine 1 according to the first embodiment, it is possible to accumulate acceleration data indicating the state of the ball screw 51 of the injection molding machine 1 and calculate the failure time and failure probability of the ball screw 51. can.
- a first function indicating the relationship between time and the acceleration peak value is obtained by the maximum likelihood estimation method, and the point in time when the acceleration peak value calculated using the first function reaches a predetermined failure determination threshold is It can be calculated as a failure time with a failure probability of 50%. Also, the point in time when the acceleration peak value calculated using the second function reaches a predetermined failure determination threshold can be calculated as the failure time with a failure probability of 16%. Furthermore, the point in time when the acceleration peak value calculated using the third function reaches a predetermined failure determination threshold can be calculated as the failure time with a failure probability of 84%.
- the current state of the ball screw 51 can be displayed using the measured value graph 45a and estimated value graphs 45b, 45c, and 45d.
- the failure timing and failure probability of the ball screw 51 are estimated based on the vibration of the ball screw 51.
- physical quantity data indicating the current or torque of the injection servomotor 50 is used.
- the processor 41 calculates a function indicating the temporal change of the peak value of the current or torque based on the physical quantity data indicating the current or torque of the injection servomotor 50, and similarly to the first embodiment, the ball screw 51 Failure time and failure probability can be calculated. Further, the failure timing and failure probability of the ball screw 51 may be calculated based on the concentration of iron powder contained in the lubricating oil of the ball screw 51 . In the first embodiment, an example of calculating the failure time and failure probability of the ball screw 51 has been described. Further, the physical quantity data indicating the state of a predetermined portion of the industrial machine may be acquired, and the failure time and failure probability of the predetermined portion may be calculated.
- the second function and the third function for estimating the value obtained by adding and subtracting the standard deviation from the average value of the acceleration peak values are exemplified, but the present invention is not limited to this.
- a function for estimating a value obtained by adding or subtracting an arbitrary predetermined deviation to or from the average value of the acceleration peak values may be calculated, and the failure time and failure probability may be estimated using the function.
- the injection molding machine 1 according to the second embodiment differs from the first embodiment in that the failure time and failure probability are calculated for each part of the ball screw shaft 51a. Since other configurations of the injection molding machine 1 are the same as those of the injection molding machine 1 according to the first embodiment, the same parts are denoted by the same reference numerals, and detailed description thereof is omitted.
- FIG. 7 is a flow chart showing the processing procedure of the calculation unit according to the second embodiment.
- the processor 41 acquires acceleration data indicating the state of the ball screw 51 from the acceleration sensor 5a via the acquisition unit 44 (step S211).
- the processor 41 also acquires angle data, in other words, position data indicating the position of the nut 51b, from the encoder 50d via the acquisition unit 44 (step S211).
- the rotation angle of the injection servomotor 50 corresponds to the position of the nut 51b on the ball screw shaft 51a.
- the calculation unit associates the acquired acceleration data, the position data, and the time data indicating the time when the acceleration data and the position data were acquired, and stores them in the storage unit 42 (step S212). Time data is obtained from the timer.
- the calculation unit calculates the first function for estimating the temporal change in the acceleration peak value that is correlated with the service life of the ball screw 51. It is calculated for each part of the screw shaft 51a (step S213).
- the processor 41 applies the second function for estimating the change over time of the value obtained by adding the standard deviation of the normal distribution to the acceleration peak value calculated using the first function. is calculated for each (step S214).
- the processor 41 calculates a third function for estimating the temporal change of the values obtained by subtracting the standard deviation of the normal distribution from the plurality of time point meter values for each part of the ball screw shaft 51a (step S215).
- the method of calculating the first to third functions is the same as in the first embodiment.
- the processor 41 uses the first function to calculate the failure time and failure probability of the ball screw 51 for each part of the ball screw shaft 51a (step S216). Similarly, the processor 41 uses the second function to calculate the failure time and failure probability of the ball screw 51 for each part of the ball screw shaft 51a (step S217). The processor 41 also uses the third function to calculate the failure time and failure probability of the ball screw 51 for each part of the ball screw shaft 51a (step S218).
- the method of calculating the failure time and failure probability using the first to third functions is the same as in the first embodiment.
- the processor 41 displays the measured value graph 45a and the estimated value graphs 45b, 45c, 45d, etc. on the display unit 45 (step S219), and ends the process.
- the acceleration data indicating the state of the ball screw 51 of the injection molding machine 1 is accumulated, and the failure time and failure probability of the ball screw 51 are calculated for each part of the ball screw shaft 51a. can be calculated.
- the injection molding machine 1 according to the third embodiment differs from the first embodiment in that the failure time and failure probability of the ball screw shaft 51a are calculated by machine learning. Since other configurations of the injection molding machine 1 are the same as those of the injection molding machine 1 according to the first embodiment, the same parts are denoted by the same reference numerals, and detailed description thereof is omitted.
- FIG. 8 is a schematic diagram showing a configuration example of the control device 4 according to the third embodiment.
- the processor 41 of the control device 4 according to the third embodiment includes a learning processing section 41a as a functional section.
- the storage unit 42 also stores a learning model 42 b for estimating the failure time and failure probability of the ball screw 51 .
- the learning processing unit 41a may be realized by software, or may be configured by hardware. Also, a part of the learning processing unit 41a may be configured by hardware.
- the processor 41 reads out the learning model 42b and the computer program 42a from the storage unit 42 and executes them.
- the learning model 42b is a neural network that outputs a failure probability when the peak value of vibration acceleration and the elapsed time, which is the operating time of the ball screw 51, are input.
- the learning model 42b includes an input layer, a hidden layer, and an output layer.
- the input layer has a plurality of nodes to which peak vibration acceleration values and elapsed times are input.
- the hidden layer includes a plurality of hidden layers having a plurality of nodes, and the nodes of the hidden layer on the input side are connected to the nodes of the input layer.
- the output layer has nodes that output failure probabilities. Each node in the output layer is connected to an intermediate layer node on the output side.
- the learning model 42b can be generated by machine learning using training data including the peak value of vibration acceleration, elapsed time, and failure probability.
- the learning processing unit 41a of the processor 41 performs machine learning on the learning model 42b by optimizing the weighting coefficients of the learning model 42b by error backpropagation using training data, error gradient descent, or the like.
- the learning model 42b has nodes corresponding to a plurality of elapsed times in the output layer, and when the peak value of the vibration acceleration is input, the failure probability is output from the node corresponding to each elapsed time. You may
- the processor 41 can calculate the failure probability of the ball screw 51 by inputting the currently detected peak value of the vibration acceleration and an arbitrary elapsed time into the learning model 42b. Using the relationship between the elapsed time and the failure probability calculated using the learning model 42b, the processor 41 displays the measured value graph 45a and the estimated value graphs 45b, 45c, and 45d on the display unit 45 in the same manner as in the first embodiment. do it.
- the failure time and failure probability of the ball screw 51 are calculated, and the measured value graph 45a and the estimated value graphs 45b, 45c, and 45d are displayed on the display unit 45. can be displayed in
- the learning model 42b using a neural network has been described in the third embodiment, it is possible to estimate the failure time and failure probability using other known machine learning models such as SVM (Support Vector Machine) and Bayesian network. can be configured to
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Abstract
Description
取得部44は、後述のエンコーダ50dから出力される回転角信号、加速度センサ5aから出力される加速度信号をAD変換し、回転角データ及び加速度データを取得する。
表示部45は、液晶パネル、有機ELディスプレイ、電子ペーパ、プラズマディスプレイ等である。表示部45は、プロセッサ41から与えられた画像データに応じた各種情報を表示する。
以下、ボールねじ軸51aの基端部側の方向を(図1中、右側)を後退方向、その反対側の方向(図1中、左方向)を前進方向と呼ぶ。また、前進方向及び後退方向を合わせて進退方向と呼ぶ。射出用サーボモータ50が駆動して大プーリ50c及びボールねじ軸51aが回転すると、その回転方向に応じてナット51bは前進方向及び後退方向へ移動する。
P=a×ebt+c…(1)
但し、
P:加速度ピーク値
t:時間
a,b,c:係数
また、プロセッサ41は、第2関数を用いて算出される加速度ピーク値が所定の故障判定閾値に達する時点を、故障確率が16%(第2確率)となる故障時期として算出する。
更に、プロセッサ41は、第3関数を用いて算出される加速度ピーク値が所定の故障判定閾値に達する時点を、故障確率が84%(第3確率)となる故障時期として算出する。
横軸は経過時間に相当する稼働時間を示し、縦軸は加速度ピーク値に相当する故障度を示す。実測値グラフ45aは、記憶部42が記憶する加速度データ及び時間データに基づく、加速度ピーク値の経時変化の実測値を示すグラフである。推定値グラフ45b,45c,45dは、それぞれ第1関数、第2関数、第3関数で求められる加速度ピーク値の経時変化を示すグラフである。
また、プロセッサ41は、故障判定閾値を示す閾値線画像45fを表示部45に表示する。更に、プロセッサ41は、現時点からの経過時間とボールねじ51の故障確率を示す正規分布画像45eを表示する。
また、第2関数を用いて算出される加速度ピーク値が所定の故障判定閾値に達する時点を、故障確率16%の故障時期として算出することができる。
更に、第3関数を用いて算出される加速度ピーク値が所定の故障判定閾値に達する時点を、故障確率84%の故障時期として算出することができる。
また、本実施形態1ではボールねじ51の故障時期及び故障確率を算出する例を説明したが、型締装置2、射出装置3の故障時期及び故障確率を算出するように構成してもよい。
更に、産業機械を構成する所定部位の状態を示す物理量データを取得し、当該所定部位の故障時期及び故障確率を算出するように構成してもよい。
実施形態2に係る射出成形機1は、ボールねじ軸51aの部位毎に故障時期及び故障確率を算出する点が実施形態1と異なる。射出成形機1のその他の構成は、実施形態1に係る射出成形機1と同様であるため、同様の箇所には同じ符号を付し、詳細な説明を省略する。
また、プロセッサ41は、複数の時点メータ値に対して、正規分布の記標準偏差を減算した値の経時変化を推定するための第3関数を、ボールねじ軸51aの部位毎に算出する(ステップS215)。
なお、第1関数~第3関数の算出方法は実施形態1と同様である。
なお、第1関数~第3関数を用いた故障時期及び故障確率の算出方法は実施形態1と同様である。
実施形態3に係る射出成形機1は、機械学習によりボールねじ軸51aの故障時期及び故障確率を算出する点が実施形態1と異なる。射出成形機1のその他の構成は、実施形態1に係る射出成形機1と同様であるため、同様の箇所には同じ符号を付し、詳細な説明を省略する。
2 型締装置
3 射出装置
4 制御装置
5 駆動装置
5a 加速度センサ
6 記録媒体
31 加熱シリンダ
32 スクリュ
50 射出用サーボモータ
50d エンコーダ
51 ボールねじ
41 プロセッサ
51 ボールねじ
51a ボールねじ軸
51b ナット
Claims (10)
- 産業機械を構成する所定部位の状態を示す物理量データを取得し、
取得した前記物理量データ及び該物理量データの取得時を示す時間データを対応付けて記憶し、
取得した前記物理量データ及び前記時間データに基づいて、前記所定部位の寿命と相関のあるパラメータ値の経時変化を推定するための関数を算出し、
算出した前記関数を用いて前記所定部位の故障時期又は故障確率を算出する
寿命推定方法。 - 前記関数を用いて算出される前記パラメータ値が、故障判定閾値に達する時点を故障時期として算出する
請求項1に記載の寿命推定方法。 - 最尤推定法にて算出した前記関数を用いて算出される前記パラメータ値が前記故障判定閾値に達する時点を故障確率が50%の故障時期として算出する
請求項2に記載の寿命推定方法。 - 最尤推定法にて、前記パラメータ値の経時変化を推定するための第1関数を算出し、
前記第1関数を用いて算出される前記パラメータ値に対して所定偏差を加算した値の経時変化を推定するための第2関数を算出し、
前記第1関数を用いて算出される前記パラメータ値に対して前記所定偏差を減算した値の経時変化を推定するための第3関数を算出し、
前記第1関数を用いて算出される前記パラメータ値が前記故障判定閾値に達する時点を、故障確率が第1確率の場合の故障時期として算出し、
前記第2関数を用いて算出される前記パラメータ値が前記故障判定閾値に達する時点を、故障確率が第2確率の場合の故障時期として算出し、
前記第3関数を用いて算出される前記パラメータ値が前記故障判定閾値に達する時点を、故障確率が第3確率の場合の故障時期として算出する
請求項2に記載の寿命推定方法。 - 前記物理量データ及び前記時間データに基づく前記パラメータ値の経時変化を示す実測値グラフと、前記第1関数、前記第2関数及び前記第3関数を示す推定値グラフと、前記故障判定閾値とを表示する
請求項4に記載の寿命推定方法。 - 前記産業機械はボールねじを有する成形機であり、
前記ボールねじの故障時期又は故障確率を算出する
請求項1から請求項5のいずれか1項に記載の寿命推定方法。 - 前記物理量データは、前記ボールねじの振動加速度、前記ボールねじを駆動するモータの電流又はトルクを示すデータであり、前記パラメータ値は、前記振動加速度、前記電流又は前記トルクのピーク値である
請求項6に記載の寿命推定方法。 - 前記成形機は、先端部にノズルを有するシリンダ内に回転方向と軸方向とに駆動可能に設けられたスクリュを備え、前記ボールねじは、回転可能に設けられたボールねじ軸と、該ボールねじ軸に螺合され該ボールねじ軸の回転に伴い進退されるナットとを有し、該ナットの進退により前記スクリュを前記軸方向に駆動するものであり、
前記ボールねじに対する前記ナットの位置を示す位置データと、該位置の前記ボールねじの状態を示す前記物理量データとを取得し、
取得した前記位置データ、前記物理量データ及び該物理量データの取得時を示す前記時間データを対応付けて記憶し、
取得した前記位置データ、前記物理量データ及び前記時間データに基づいて、前記ボールねじの寿命と相関のある前記パラメータ値の経時変化を推定するための前記関数を、前記ボールねじ軸の部位毎に算出する
請求項7に記載の寿命推定方法。 - 産業機械を構成する所定部位の状態を示す物理量データを取得する取得部と、
取得した前記物理量データ及び該物理量データの取得時を示す時間データを対応付けて記憶する記憶部と、
取得した前記物理量データ及び前記時間データに基づいて、前記所定部位の寿命と相関のあるパラメータ値の経時変化を推定するための関数を算出し、算出した前記関数を用いて前記所定部位の故障時期又は故障確率を算出する演算部と
を備える寿命推定装置。 - 産業機械を構成する所定部位の状態を示す物理量データを取得し、
取得した前記物理量データ及び該物理量データの取得時を示す時間データを対応付けて記憶し、
取得した前記物理量データ及び前記時間データに基づいて、前記所定部位の寿命と相関のあるパラメータ値の経時変化を推定するための関数を算出し、
算出した前記関数を用いて前記所定部位の故障時期又は故障確率を算出する
処理をコンピュータに実行させるためのコンピュータプログラム。
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WO2020136823A1 (ja) * | 2018-12-27 | 2020-07-02 | 三菱電機株式会社 | 異常診断装置および異常診断方法 |
JP2021074918A (ja) * | 2019-11-06 | 2021-05-20 | 株式会社日本製鋼所 | 異常検知装置、異常検知方法及びコンピュータプログラム |
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JP2019166702A (ja) | 2018-03-23 | 2019-10-03 | 株式会社日本製鋼所 | 機械学習器により成形条件を調整する射出成形機システム |
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