Material testing machine and control method of material testing machine

Abstract

The present invention provides a material testing machine and a control method for the material testing machine, which can reduce the burden on operators. The tensile testing machine (1) includes: a processing filter (FP) for removing noise components contained in a test force measurement signal (SG1) output by a load cell (14); and an adjustment unit (544) for adjusting the frequency characteristics of the processing filter (FP).

Description

Technical Field

[0001] The invention relates to a material testing machine and a control method of the material testing machine. Background Art

[0002] In material testing machines, various technologies are known for removing noise components contained in detection signals output by sensors.

[0003] For example, the material testing machine described in Patent Document 1 describes the following: detecting a break point from the original data as a change point, segmenting the data before and after the break point to obtain segmented data, performing low-pass filtering on each segmented data, and when the filtering of all segmented data is completed, reconstructing the time series data with the natural vibration frequency removed before and after the break point, and connecting the reconstructed data at the break point.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-56614 Summary of the Invention

[0007] [Problems to be solved by the invention]

[0008] However, in the material testing machine described in Patent Document 1, the operator must adjust the frequency characteristics of a filter such as a low-pass filter every time the material and shape of the test piece or the type of the gripper changes, which places a burden on the operator.

[0009] The noise components contained in the detection signals output by sensors often have high frequencies. Therefore, for example, lowering the cutoff frequency of a low-pass filter can sufficiently remove the noise components, but this can sometimes reduce the responsiveness of the detection signal. Conversely, increasing the cutoff frequency of a low-pass filter improves the responsiveness of the detection signal, but sometimes fails to fully remove the noise components.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a material testing machine that can reduce the burden on an operator.

[0011] [Technical means to solve the problem]

[0012] A material testing machine according to a first aspect of the present invention includes: a processing filter for removing noise components included in a detection signal output by a sensor; and an adjustment unit for adjusting frequency characteristics of the processing filter.

[0013] A second aspect of the present invention is a control method for a material testing machine, wherein the material testing machine includes a processing filter, the processing filter removes noise components contained in a detection signal output by a sensor, and the control method for the material testing machine includes: an adjustment step, adjusting the frequency characteristics of the processing filter.

[0014] [Effects of the Invention]

[0015] The control methods for the materials testing machine of the first aspect and the materials testing machine of the second aspect of the present invention each adjust the frequency characteristics of a processing filter that removes noise components from the detection signal output by a sensor. This reduces the burden on the operator. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a diagram showing an example of the structure of the tensile testing machine according to the present embodiment.

[0017] Figure 2 This is a diagram showing an example of the configuration of a control circuit unit according to this embodiment.

[0018] Figure 3 This is a flowchart showing an example of processing by the control unit of this embodiment.

[0019] [Explanation of Symbols]

[0020] 1: Tensile testing machine (material testing machine)

[0021] 2: Tensile testing machine body

[0022] 4: Control unit

[0023] 10: Crosshead

[0024] 12: Load mechanism

[0025] 14: Force sensor (sensor)

[0026] 15: Displacement sensor

[0027] 20: Rotary encoder

[0028] 21: Upper grip

[0029] 22: Lower grip

[0030] 26: Platform

[0031] 28, 29: Screw

[0032] 30: Overall control device

[0033] 32: Display device (display)

[0034] 34: Test program execution device

[0035] 40: Signal input / output unit

[0036] 42: First sensor amplifier

[0037] 43: Counter circuit

[0038] 44: Servo amplifier

[0039] 45: Second sensor amplifier

[0040] 50: Control circuit unit

[0041] 51: Ministry of Communications

[0042] 52: Feedback Control Unit

[0043] 53: Control Department

[0044] 54: Processor

[0045] 541: Speed ​​determination unit

[0046] 542: First Judgment Unit

[0047] 543: Second Judgment Unit

[0048] 544: Adjustment Department

[0049] 545: Selection Department

[0050] 55: Memory

[0051] 56: Low-pass filter

[0052] 561: First low-pass filter

[0053] 562: Second low-pass filter 563: Third low-pass filter

[0054] FA: response frequency

[0055] FC: Cutoff frequency

[0056] FC1: First frequency

[0057] FC2: Second frequency

[0058] FC3: Third Frequency

[0059] FD: Test force measurement value

[0060] FD1: First test force measurement value

[0061] FD2: Second test force measurement value

[0062] FD3: third test force measurement value

[0063] FP: Processing Filter

[0064] LP2: Two low-pass filters

[0065] SG1: Test force measurement signal

[0066] SG2: Rotation measurement signal

[0067] SG3: Extension measurement signal

[0068] TP: Test piece

[0069] VC: Movement Speed

[0070] VCA: Threshold

[0071] XD: Displacement measurement value

[0072] ΔF1: first threshold

[0073] ΔF2: Second threshold DETAILED DESCRIPTION

[0074] Hereinafter, this embodiment will be described with reference to the drawings.

[0075] [1. Structure of the tensile testing machine]

[0076] Figure 1 It is a diagram showing an example of the structure of the tensile testing machine 1 according to the present embodiment.

[0077] The tensile testing machine 1 of this embodiment applies a test force F to a test piece TP to perform a tensile test to measure mechanical properties of the sample, such as tensile strength, yield point, elongation, and contraction. The test force F is the tensile force.

[0078] The tensile testing machine 1 includes a tensile testing machine body 2 for applying a test force F to a test piece TP, which is a test object, to perform a tensile test; and a control unit 4 for controlling the tensile test performed by the tensile testing machine body 2 .

[0079] In addition, the tensile testing machine 1 corresponds to an example of a “material testing machine”.

[0080] The testing machine body 2 includes a platform 26; a pair of lead screws 28 and 29 rotatably mounted upright on the platform 26 while oriented in a vertical direction; a crosshead 10 movable along the lead screws 28 and 29; a loading mechanism 12 for moving the crosshead 10 to apply a load to the test piece TP; and a load cell 14. The load cell 14 measures the tensile load applied to the test piece TP, i.e., the test force F, and outputs a test force measurement signal SG1.

[0081] The load mechanism 12 includes worm reducers 16 and 17 connected to the lower ends of the lead screws 28 and 29, a servo motor 18 connected to the worm reducers 16 and 17, and a rotary encoder 20. The rotary encoder 20 is a sensor that measures the rotation of the servo motor 18 and outputs a rotation measurement signal SG2 having a number of pulses corresponding to the rotation to the control unit 4.

[0082] The load mechanism 12 transmits the rotation of the servo motor 18 to the pair of lead screws 28 and 29 via the worm reducers 16 and 17 . The lead screws 28 and 29 rotate synchronously, so that the crosshead 10 moves up and down along the lead screws 28 and 29 .

[0083] An upper gripper 21 is attached to the crosshead 10 for gripping the upper end of the test piece TP, and a lower gripper 22 is attached to the platform 26 for gripping the lower end of the test piece TP. During a tensile test, the tester body 2 raises the crosshead 10 under the control of the control unit 4 while gripping the ends of the test piece TP via the upper gripper 21 and the lower gripper 22, thereby applying a test force F to the test piece TP.

[0084] A displacement sensor 15 is disposed on the test piece TP. For example, a dumbbell-shaped test piece with a tapered center is used. The displacement sensor 15 measures the distance between a pair of measuring points on the test piece TP to determine an extension measurement value ED and output an extension measurement signal SG3. The pair of measuring points are disposed at the upper and lower portions of the tapered region of the test piece TP.

[0085] The control unit 4 includes an overall control device 30 , a display device 32 , and a test program execution device 34 .

[0086] The overall control device 30 is a device that centrally controls the tester body 2 and is connected to the tester body 2 so as to be capable of transmitting and receiving signals. Signals received from the tester body 2 include the test force measurement signal SG1 output by the load cell 14, the rotation measurement signal SG2 output by the rotary encoder 20, the extension measurement signal SG3 output by the displacement sensor 15, and other appropriate signals required for control or testing.

[0087] The display device 32 includes a liquid crystal display (LCD) or the like, and displays various information based on signals input from the overall control device 30. For example, during a tensile test, the overall control device 30 displays the extension measurement value ED, which is the measured value of the extension of the test piece TP, based on the extension measurement signal SG3, on the display device 32. Furthermore, during a tensile test, the overall control device 30 displays the displacement measurement value XD, which indicates the displacement of the crosshead 10 based on the rotation measurement signal SG2, on the display device 32.

[0088] The display device 32 corresponds to an example of a “display”.

[0089] The tensile test program execution device 34 is a device having functions such as accepting user operations such as setting operations for various setting parameters such as test conditions for tensile testing or execution instruction operations and outputting them to the overall control device 30, and analyzing data of test force measurement values ​​FD.

[0090] Next, the overall control device 30 of this embodiment will be further described. The overall control device 30 includes a signal input / output unit 40 and a control circuit unit 50 .

[0091] The signal input / output unit 40 constitutes an input / output interface circuit for transmitting and receiving signals with the tester body 2 , and in this embodiment includes a first sensor amplifier 42 , a second sensor amplifier 45 , a counter circuit 43 , and a servo amplifier 44 .

[0092] The first sensor amplifier 42 is an amplifier that amplifies the test force measurement signal SG1 outputted from the load cell 14 and outputs the amplified signal to the control circuit unit 50 .

[0093] The second sensor amplifier 45 is an amplifier that amplifies the extension measurement signal SG3 outputted from the displacement sensor 15 and outputs the amplified signal to the control circuit unit 50 .

[0094] The counter circuit 43 counts the number of pulses of the rotation measurement signal SG2 output by the rotary encoder 20 and outputs the rotation amount of the servo motor 18, that is, the displacement measurement value XD of the crosshead 10 raised and lowered by the rotation of the servo motor 18, to the control circuit unit 50 as a digital signal.

[0095] The servo amplifier 44 is a device that controls the servo motor 18 under the control of the control circuit unit 50 .

[0096] The control circuit unit 50 includes a communication section 51 , a feedback control section 52 , and a control section 53 .

[0097] The control unit 53 includes a processor 54 and a memory 55 .

[0098] Reference Figure 2 The control unit 53 , the processor 54 , and the memory 55 will be described.

[0099] The control circuit unit 50 includes a computer, which includes a storage device such as a hard disk drive (HDD) or a solid state drive (SSD), an interface circuit with the signal input / output unit 40, a communication device for communicating with the tensile test program execution device 34, a display control circuit for controlling the display device 32, and various electronic circuits.

[0100] Furthermore, the processor 54 of the control unit 53 of the control circuit unit 50 executes the control program stored in the memory 55 or the storage device, thereby realizing Figure 1 The functional parts shown.

[0101] Furthermore, an analog / digital (A / D) converter is provided in the interface circuit with the signal input / output unit 40, and the test force measurement signal SG1 and the extension measurement signal SG3, which are analog signals, are converted into digital signals through the A / D converter.

[0102] In addition, the control circuit unit 50 is not limited to a computer, and may also include one or more appropriate circuits such as an integrated circuit (IC) chip or a large-scale integrated circuit (LSI).

[0103] The communication unit 51 communicates with the tensile test program execution device 34, receiving test condition settings, set values ​​for various setting parameters, tensile test execution instructions, and interruption instructions from the test program execution device 34. Furthermore, the communication unit 51 transmits the extension measurement value ED based on the extension measurement signal SG3 and the test force measurement value FD based on the test force measurement signal SG1 to the tensile test program execution device 34 at appropriate times. Furthermore, the communication unit 51 transmits the displacement measurement value XD based on the rotation measurement signal SG2 to the tensile test program execution device 34 at appropriate times.

[0104] The feedback control unit 52 performs feedback control on the servo motor 18 of the tester body 2 to execute the tensile test. The feedback control unit 52 is a circuit that performs feedback control on the servo motor 18.

[0105] When the feedback control unit 52 performs position control, for example, the feedback control unit 52 performs position control on the test force measurement value FD output by the load cell 14. In this case, the feedback control unit 52 calculates the command value dX of the displacement measurement value XD so that the test force measurement value FD is consistent with the test force target value FT, and outputs a command signal A4 indicating the command value dX to the servo amplifier 44. The test force target value FT indicates the target value of the test force measurement value FD.

[0106] Furthermore, the term "position control" refers to control performed so that a detection value measured by a sensor or the like coincides with a target value.

[0107] Furthermore, the case of executing position control is described, but the feedback control unit 52 may also execute speed control. "Speed ​​control" refers to control so that the amount of change per unit time of a detection value measured by a sensor or the like matches its target value.

[0108] [2. Structure of the control circuit unit]

[0109] Figure 2 1 is a diagram showing an example of the configuration of the control circuit unit 50 according to the present embodiment.

[0110] The control unit 53 includes, for example, a personal computer, and controls the operation of the control circuit unit 50. The control unit 53 includes a processor 54 and a memory 55.

[0111] The processor 54 includes a central processing unit (CPU) or a microprocessor (MPU).

[0112] The memory 55 includes a read-only memory (ROM) or a random access memory (RAM).

[0113] The control unit 53 is not limited to a personal computer, and may include one or more appropriate circuits such as an IC chip or an integrated circuit such as an LSI. Furthermore, the control unit 53 may include, for example, a tablet terminal or a smartphone.

[0114] Furthermore, the control unit 53 may include programmed hardware such as a digital signal processor (DSP) or a field programmable gate array (FPGA). Furthermore, the control unit 53 may include a system-on-a-chip (SoC) FPGA.

[0115] The control circuit unit 50 further includes, for example, a low-pass filter 56 .

[0116] The low-pass filter 56 is a filter that does not attenuate components with frequencies lower than the cutoff frequency FC but attenuates components with frequencies higher than the cutoff frequency FC in the test force measurement signal SG1 , which is the detection signal of the load cell 14 , for example.

[0117] Specifically, the load cell 14 outputs its detection signal, namely, the test force measurement signal SG1, to the first sensor amplifier 42. The first sensor amplifier 42 amplifies the test force measurement signal SG1 and outputs the test force measurement value FD to the low-pass filter 56. The low-pass filter 56 does not attenuate components of the test force measurement value FD having frequencies lower than the cutoff frequency FC, but attenuates components having frequencies higher than the cutoff frequency FC.

[0118] The low-pass filter 56 corresponds to an example of a “processing filter”.

[0119] In this embodiment, the processing filter is described as a low-pass filter 56 , but any processing filter that removes noise components contained in the detection signal output by the sensor may be used. For example, the processing filter may be a band-pass filter.

[0120] Furthermore, while this embodiment describes a case where the low-pass filter 56 attenuates high-frequency components contained in the test force measurement signal SG1, which is the detection signal of the load cell 14, the present invention is not limited to this embodiment. The low-pass filter 56 only needs to attenuate high-frequency components contained in the detection signal of the sensor disposed in the tensile testing machine 1. For example, the low-pass filter 56 may also attenuate high-frequency components contained in the extension measurement signal SG3, which is the detection signal of the displacement sensor 15.

[0121] That is, the load cell 14 corresponds to an example of a “sensor”.

[0122] In other words, in this embodiment, the case where the “sensor” is the load cell 14 is described, but the “sensor” may be, for example, the displacement sensor 15 .

[0123] The low-pass filter 56 includes a first low-pass filter 561 , a second low-pass filter 562 , and a third low-pass filter 563 .

[0124] The test force measurement value FD is input to each of the first to third low-pass filters 561 to 563. In other words, each of the first to third low-pass filters 561 to 563 attenuates high-frequency components contained in the test force measurement signal SG1, which is the detection signal of the load cell 14.

[0125] The first low-pass filter 561 is configured to have better responsiveness than the second low-pass filter 562 and the third low-pass filter 563 .

[0126] The cutoff frequency FC of the first low-pass filter 561 is a first frequency FC1. The first frequency FC1 is set, for example, to be higher than the response frequency FA required for controlling the tensile testing machine 1. The response frequency FA is, for example, 100 Hz. The first frequency FC1 is, for example, 300 Hz. The first low-pass filter 561 outputs a first test force measurement value FD1 to the control unit 53.

[0127] The first low-pass filter 561 corresponds to an example of “two low-pass filters”.

[0128] The second low-pass filter 562 is configured to have better high-frequency noise removal performance than the first low-pass filter 561 , and is configured to have better responsiveness than the third low-pass filter 563 .

[0129] The cutoff frequency FC of the second low-pass filter 562 is the second frequency FC2. The second frequency FC2 is set lower than the first frequency FC1. The second frequency FC2 is, for example, 3 Hz. The second low-pass filter 562 outputs the second test force measurement value FD2 to the control unit 53.

[0130] The second low-pass filter 562 corresponds to an example of “two low-pass filters”.

[0131] Furthermore, the second low-pass filter 562 corresponds to an example of a “processing filter”.

[0132] The third low-pass filter 563 is configured to have a higher performance in removing high-frequency noise than the first low-pass filter 561 and the second low-pass filter 562 .

[0133] The cutoff frequency FC of the third low-pass filter 563 is the third frequency FC3. The third frequency FC3 is set lower than the second frequency FC2. The third frequency FC3 is, for example, 0.3 Hz. The third low-pass filter 563 outputs the third test force measurement value FD3 to the control unit 53.

[0134] The third low-pass filter 563 corresponds to an example of “two low-pass filters”.

[0135] Furthermore, the third low-pass filter 563 corresponds to an example of a “processing filter”.

[0136] In addition to the first to third test force measurement values ​​FD1 to FD3, the control unit 53 receives the displacement measurement value XD from the counter circuit 43. The displacement measurement value XD represents the displacement of the crosshead 10. The displacement measurement value XD is generated by the counter circuit 43 based on the rotation measurement signal SG2 output by the rotary encoder 20.

[0137] In this embodiment, the low-pass filter 56 includes three low-pass filters, namely, the first low-pass filter 561 to the third low-pass filter 563. However, the low-pass filter 56 may also include two low-pass filters. In this case, the structure and processing can be simplified. Furthermore, the low-pass filter 56 may also include four or more low-pass filters. In this case, the frequency characteristics of the processing filter FP can be more appropriately adjusted.

[0138] [3. Structure of the control unit]

[0139] like Figure 2 As shown, the control unit 53 includes a speed determination unit 541 , a first determination unit 542 , a second determination unit 543 , an adjustment unit 544 , and a selection unit 545 .

[0140] Specifically, the processor 54 of the control unit 53 functions as a speed determination unit 541 , a first determination unit 542 , a second determination unit 543 , an adjustment unit 544 , and a selection unit 545 by executing a control program stored in the memory 55 or a storage device.

[0141] The speed determination unit 541 calculates the moving speed VC of the crosshead 10 and determines whether the moving speed VC is equal to or greater than a threshold value VCA.

[0142] The speed determination unit 541 calculates the moving speed VC based on the displacement measurement value XD input from the counter circuit 43. Specifically, the speed determination unit 541 calculates the amount of change in the displacement measurement value XD per unit time as the moving speed VC.

[0143] The first determination unit 542 determines whether the difference between the output signals of the two low-pass filters LP2 selected by the selection unit 545 is equal to or greater than a first threshold value ΔF1 .

[0144] The first threshold value ΔF1 is set based on the full scale FS of the test force measurement value FD. For example, the first threshold value ΔF1 is set to a value of 1 / 20000 of the full scale FS of the test force measurement value FD.

[0145] When the selector 545 selects the first low-pass filter 561 and the second low-pass filter 562 as the two low-pass filters LP2 , the first determiner 542 determines whether the absolute value of the difference between the first test force measurement value FD1 and the second test force measurement value FD2 is greater than or equal to the first threshold ΔF1 .

[0146] The second determination unit 543 determines whether the difference between the output signals of the two low-pass filters LP2 selected by the selection unit 545 is equal to or smaller than a second threshold value ΔF2 .

[0147] The second threshold value ΔF2 is set to a value greater than the first threshold value ΔF1. For example, the second threshold value ΔF2 is set to a value twice as large as the first threshold value ΔF1.

[0148] When the selector 545 selects the first low-pass filter 561 and the third low-pass filter 563 as the two low-pass filters LP2 , the second determiner 543 determines whether the absolute value of the difference between the first test force measurement value FD1 and the third test force measurement value FD3 is less than or equal to the second threshold ΔF2 .

[0149] If the speed determination unit 541 determines that the moving speed VC is equal to or greater than the threshold value VCA, the adjustment unit 544 sets the third low-pass filter 563 as the processing filter FP. The threshold value VCA is set in advance based on experimental results or the like.

[0150] If the speed determination unit 541 determines that the moving speed VC is less than the threshold value VCA, the adjustment unit 544 adjusts the frequency characteristics of the processing filter FP. The processing filter FP removes noise components included in the test force measurement signal SG1 output by the load cell 14.

[0151] The output signal of the processing filter FP is used as a display signal displayed on the display device 32 .

[0152] The adjustment unit 544 receives the test force measurement signal SG1 output by the load cell 14 and adjusts the frequency characteristics of the processing filter FP based on the difference between the output signals of the two low-pass filters LP2 having different frequency characteristics.

[0153] Specifically, the processing filter FP includes a low-pass filter, and the adjustment unit 544 reduces the cutoff frequency of the processing filter FP based on the determination result of the first determination unit 542 .

[0154] More specifically, the adjustment unit 544 switches the processing filter FP from the second low-pass filter 562 to the third low-pass filter 563 based on the determination result of the first determination unit 542. Specifically, if the difference between the output signals of the two low-pass filters LP2 selected by the selection unit 545 is greater than or equal to the first threshold ΔF1, the adjustment unit 544 switches the processing filter FP from the second low-pass filter 562 to the third low-pass filter 563.

[0155] For example, when the selection unit 545 selects the first low-pass filter 561 and the second low-pass filter 562 as the two low-pass filters LP2, the first determination unit 542 determines whether the absolute value of the difference between the first test force measurement value FD1 and the second test force measurement value FD2 is greater than or equal to the first threshold value ΔF1. Furthermore, if the first determination unit 542 determines that the absolute value of the difference between the first test force measurement value FD1 and the third test force measurement value FD3 is greater than or equal to the first threshold value ΔF1, the adjustment unit 544 switches the processing filter FP from the second low-pass filter 562 to the third low-pass filter 563.

[0156] Furthermore, the adjustment unit 544 increases the cutoff frequency of the processing filter FP according to the determination result of the second determination unit 543 .

[0157] Specifically, the adjustment unit 544 switches the processing filter FP from the third low-pass filter 563 to the second low-pass filter 562 based on the determination result of the second determination unit 543. In other words, if the difference between the output signals of the two low-pass filters LP2 selected by the selection unit 545 is equal to or less than the second threshold value ΔF2, the adjustment unit 544 switches the processing filter FP from the third low-pass filter 563 to the second low-pass filter 562.

[0158] For example, when the selection unit 545 selects the first low-pass filter 561 and the third low-pass filter 563 as the two low-pass filters LP2, the second determination unit 543 determines whether the absolute value of the difference between the first test force measurement value FD1 and the third test force measurement value FD3 is less than or equal to the second threshold value ΔF2. Furthermore, if the second determination unit 543 determines that the absolute value of the difference between the first test force measurement value FD1 and the third test force measurement value FD3 is less than or equal to the second threshold value ΔF2, the adjustment unit 544 switches the processing filter FP from the third low-pass filter 563 to the second low-pass filter 562.

[0159] The selection unit 545 selects two low-pass filters LP2 from the first to third low-pass filters 561 to 563 .

[0160] For example, when the third low-pass filter 563 is set as the processing filter FP, the selection unit 545 selects the first low-pass filter 561 and the third low-pass filter 563 as the two low-pass filters LP2 .

[0161] Furthermore, for example, when the second low-pass filter 562 is set as the processing filter FP, the selection unit 545 selects the first low-pass filter 561 and the second low-pass filter 562 as two low-pass filters LP2 .

[0162] In other words, the selection unit 545 selects the first low-pass filter 561 and the low-pass filter set as the processing filter FP as the two low-pass filters LP2.

[0163] The selector 545 selects the first low-pass filter 561 and the low-pass filter set as the processing filter FP as the two low-pass filters LP2. Therefore, the adjuster 544 can appropriately switch the processing filter FP between the third low-pass filter 563 and the second low-pass filter 562 based on the determination results of the first determiner 542 and the second determiner 543.

[0164] That is, one of the two low-pass filters LP2 is the first low-pass filter 561 , and therefore the adjustment unit 544 can adjust the frequency characteristics of the processing filter FP based on the first test force measurement value FD1 having good responsiveness.

[0165] Furthermore, since the other of the two low-pass filters LP2 is set as the processing filter FP, the adjustment unit 544 can adjust the frequency characteristics of the processing filter FP based on the signal used as the display signal displayed on the display device 32 .

[0166] When the moving speed VC is zero, that is, when the crosshead 10 is stopped, the moving speed VC is less than the threshold value VCA, so the adjustment unit 544 adjusts the frequency characteristics of the processing filter FP. In other words, when the crosshead 10 is stopped, the adjustment unit 544 appropriately adjusts the frequency characteristics of the processing filter FP.

[0167] On the other hand, in order to satisfy the test conditions for determining the suitability of the tensile testing machine 1 , the noise component must be below a predetermined value when the crosshead 10 is stopped.

[0168] The tensile testing machine 1 of this embodiment appropriately adjusts the frequency characteristics of the processing filter FP when the crosshead 10 is stopped, thereby increasing the possibility of satisfying the test conditions.

[0169] [4. Operation of the Control Unit]

[0170] Next, refer to Figure 3 The processing of the control unit 53 will be described.

[0171] Figure 3 This is a flowchart showing an example of the processing of the control unit 53 in this embodiment.

[0172] First, in step S101 , the speed determination unit 541 calculates the moving speed VC of the crosshead 10 and determines whether the moving speed VC is equal to or greater than a threshold value VCA.

[0173] If the speed determination unit 541 determines that the moving speed VC is equal to or greater than the threshold value VCA (step S101 ; Yes), the process proceeds to step S103 .

[0174] Next, in step S103, the adjustment section 544 sets the third low-pass filter 563 as the processing filter FP. Then, the process returns to step S101.

[0175] If the speed determination unit 541 determines that the moving speed VC is not equal to or greater than the threshold value VCA (step S101 ; No), the process proceeds to step S105 .

[0176] Next, in step S105 , the adjustment unit 544 determines whether the second low-pass filter 562 is set as the processing filter FP.

[0177] If the adjustment unit 544 determines that the second low-pass filter 562 has not been set as the processing filter FP (step S105; No), that is, if the third low-pass filter 563 has been set as the processing filter FP, the process proceeds to step S117. If the adjustment unit 544 determines that the second low-pass filter 562 has been set as the processing filter FP (step S105; Yes), the process proceeds to step S107.

[0178] Next, in step S107 , the selection unit 454 selects the first low-pass filter 561 and the second low-pass filter 562 as two low-pass filters LP2 , and the first determination unit 542 acquires the first test force measurement value FD1 .

[0179] Next, in step S109 , the first determination section 542 acquires a second test force measurement value FD2 .

[0180] Next, in step S111 , the first determination unit 542 calculates the difference between the first test force measurement value FD1 and the second test force measurement value FD2 , that is, the absolute value of the difference between the first test force measurement value FD1 and the second test force measurement value FD2 .

[0181] Next, in step S113 , the first determination unit 542 determines whether the difference between the first test force measurement value FD1 and the second test force measurement value FD2 is greater than or equal to a first threshold value ΔF1 .

[0182] If the first determination unit 542 determines that the difference between the first test force measurement value FD1 and the second test force measurement value FD2 is not greater than the first threshold value ΔF1 (step S113; No), the process returns to step S101. If the first determination unit 542 determines that the difference between the first test force measurement value FD1 and the second test force measurement value FD2 is greater than the first threshold value ΔF1 (step S113; Yes), the process proceeds to step S115.

[0183] Next, in step S115, the adjustment unit 544 switches the processing filter FP from the second low-pass filter 562 to the third low-pass filter 563. Then, the process returns to step S101.

[0184] If the adjustment unit 544 determines that the second low-pass filter 562 has not been set as the processing filter FP (step S105; no), that is, if the third low-pass filter 563 has been set as the processing filter FP, then in step S117, the selection unit 454 selects the first low-pass filter 561 and the third low-pass filter 563 as two low-pass filters LP2, and the second determination unit 543 obtains the first test force measurement value FD1.

[0185] Next, in step S119 , the second determination section 543 obtains a third test force measurement value FD3 .

[0186] Next, in step S121 , the second determination unit 543 calculates the difference between the first test force measurement value FD1 and the third test force measurement value FD3 , that is, the absolute value of the difference between the first test force measurement value FD1 and the third test force measurement value FD3 .

[0187] Next, in step S123 , the second determination unit 543 determines whether the difference between the first test force measurement value FD1 and the third test force measurement value FD3 is equal to or smaller than a second threshold value ΔF2 .

[0188] If the second determination unit 543 determines that the difference between the first test force measurement value FD1 and the third test force measurement value FD3 is not less than the second threshold value ΔF2 (step S123; No), the process returns to step S101. If the second determination unit 543 determines that the difference between the first test force measurement value FD1 and the third test force measurement value FD3 is less than the second threshold value ΔF2 (step S123; Yes), the process proceeds to step S125.

[0189] Next, in step S125, the adjustment unit 544 switches the processing filter FP from the third low-pass filter 563 to the second low-pass filter 562. Then, the process returns to step S101.

[0190] Step S115 and step S125 correspond to an example of an “adjustment step”.

[0191] In this manner, the adjustment unit 544 adjusts the frequency characteristics of the processing filter FP that removes noise components included in the test force measurement value FD output by the load cell 14. Therefore, the burden on the operator can be reduced.

[0192] Specifically, if the first determination unit 542 determines that the absolute value of the difference between the first test force measurement value FD1 and the second test force measurement value FD2 is greater than the first threshold value ΔF1, the adjustment unit 544 switches the processing filter FP from the second low-pass filter 562 to the third low-pass filter 563. Therefore, high-frequency noise can be appropriately removed.

[0193] Furthermore, if the second determination unit 543 determines that the absolute value of the difference between the first test force measurement value FD1 and the third test force measurement value FD3 is less than or equal to the second threshold value ΔF2, the adjustment unit 544 switches the processing filter FP from the third low-pass filter 563 to the second low-pass filter 562. Therefore, the responsiveness of the processing filter FP can be appropriately improved.

[0194] Furthermore, if the moving speed VC is greater than or equal to the threshold value VCA, the adjustment unit 544 sets the processing filter FP to the third low-pass filter 563. Since the amplitude of high-frequency noise is large when the moving speed VC is greater than or equal to the threshold value VCA, setting the processing filter FP to the third low-pass filter 563 can appropriately suppress high-frequency noise.

[0195] [5. Form and Effect]

[0196] It should be understood by those skilled in the art that the above-described embodiments and modifications are specific examples of the following aspects.

[0197] (Item 1)

[0198] A material testing machine according to a first aspect includes: a processing filter for removing noise components contained in a detection signal output by a sensor; and an adjustment unit for adjusting frequency characteristics of the processing filter.

[0199] The material testing machine according to the first aspect includes: a processing filter for removing noise components included in the detection signal output by the sensor; and an adjustment unit for adjusting the frequency characteristics of the processing filter.

[0200] Therefore, the operator does not need to adjust the frequency characteristics of the processing filter, thereby reducing the burden on the operator.

[0201] (Second Item)

[0202] In the material testing machine described in the first aspect, the output signal of the processing filter is used as a display signal to be displayed on a display.

[0203] According to the material testing machine described in the second aspect, the output signal of the processing filter is used as a display signal displayed on a display.

[0204] Therefore, the noise component included in the display signal can be appropriately removed by the processing filter, so that an appropriate display signal can be displayed on the display.

[0205] (Item 3)

[0206] In the material testing machine described in the first or second aspect, the adjustment unit inputs the detection signal output by the sensor and adjusts the frequency characteristics of the processing filter based on the difference between output signals of two low-pass filters having different frequency characteristics.

[0207] According to the material testing machine described in the third aspect, the adjustment unit inputs the detection signal output by the sensor and adjusts the frequency characteristics of the processing filter based on the difference between output signals of two low-pass filters having different frequency characteristics.

[0208] Therefore, the adjustment unit can appropriately adjust the frequency characteristics of the processing filter.

[0209] (Item 4)

[0210] The material testing machine described in the third item further includes: a first determination unit, which determines whether the difference between the output signals of the two low-pass filters is greater than a first threshold value, the processing filter includes a low-pass filter, and the adjustment unit reduces the cutoff frequency of the processing filter according to the determination result of the first determination unit.

[0211] According to the material testing machine described in the fourth aspect, when the difference between the output signals of the two low-pass filters is equal to or greater than a first threshold value, the adjustment unit reduces the cutoff frequency of the processing filter.

[0212] Therefore, the adjustment unit can appropriately remove high-frequency noise included in the output of the processing filter.

[0213] (Item 5)

[0214] The material testing machine described in the fourth item includes: a first low-pass filter having a cutoff frequency of a first frequency; a second low-pass filter having a cutoff frequency of a second frequency lower than the first frequency; a third low-pass filter having a cutoff frequency of a third frequency lower than the second frequency; and a selection unit that selects the two low-pass filters from the first low-pass filter, the second low-pass filter, and the third low-pass filter, wherein when the second low-pass filter is set as the processing filter, the selection unit selects the first low-pass filter and the second low-pass filter as the two low-pass filters, and the adjustment unit switches the processing filter from the second low-pass filter to the third low-pass filter based on the determination result of the first determination unit.

[0215] According to the material testing machine described in item 5, when the difference between the output signals of the two low-pass filters is equal to or greater than a first threshold, the adjustment unit switches the processing filter from the second low-pass filter to the third low-pass filter.

[0216] Therefore, high-frequency noise included in the output of the processing filter can be appropriately removed with a simple configuration.

[0217] (Item 6)

[0218] The material testing machine described in the third item further includes: a second determination unit, which determines whether the difference between the output signals of the two low-pass filters is below a second threshold value, the processing filter includes a low-pass filter, and the adjustment unit increases the cutoff frequency of the processing filter according to the determination result of the second determination unit.

[0219] According to the material testing machine described in item 6, when the difference between the output signals of the two low-pass filters is equal to or smaller than a second threshold value, the adjustment unit increases the cutoff frequency of the processing filter.

[0220] Therefore, the adjustment unit can appropriately improve the responsiveness of the processing filter.

[0221] (Item 7)

[0222] The material testing machine described in item 6 includes: a first low-pass filter having a cutoff frequency of a first frequency; a second low-pass filter having a cutoff frequency of a second frequency lower than the first frequency; and a third low-pass filter having a cutoff frequency of a third frequency lower than the second frequency, and the material testing machine includes a selection unit, the selection unit selecting the two low-pass filters from the first low-pass filter, the second low-pass filter, and the third low-pass filter; when the third low-pass filter is set as the processing filter, the selection unit selects the first low-pass filter and the third low-pass filter as the two low-pass filters; and the adjustment unit switches the processing filter from the third low-pass filter to the second low-pass filter based on the determination result of the second determination unit.

[0223] According to the material testing machine described in item 7, when the difference between the output signals of the two low-pass filters is equal to or smaller than a second threshold value, the adjustment unit switches the processing filter from the third low-pass filter to the second low-pass filter.

[0224] Therefore, the responsiveness of the processing filter can be appropriately improved with a simple configuration.

[0225] (Item 8)

[0226] In a second aspect of a material testing machine control method, the material testing machine includes a processing filter that removes noise components contained in a detection signal output by a sensor. The material testing machine control method includes an adjustment step of adjusting a frequency characteristic of the processing filter.

[0227] According to the control method of the material testing machine described in the eighth aspect, the same operation and effect as that of the material testing machine described in the first aspect are achieved.

[0228] [6. Other Implementation Methods]

[0229] The tensile testing machine 1 of the present embodiment is merely an example of the form of the material testing machine of the present invention, and can be arbitrarily modified and applied without departing from the scope of the present invention.

[0230] For example, this embodiment describes a case where the material testing machine is a tensile testing machine 1, but this embodiment is not limited to this. Any material testing machine can be used as long as it can apply a test force to a test piece TP, causing the test piece TP to deform and perform material testing. For example, the material testing machine may also be a compression testing machine, a bending testing machine, or a torsion testing machine.

[0231] Furthermore, in the present embodiment, the case where the “sensor” is the load cell 14 has been described, but the “sensor” may be, for example, the displacement sensor 15 .

[0232] Furthermore, in this embodiment, the processing filter FP includes a low-pass filter, but the processing filter FP only needs to remove noise components included in the detection signal output by the sensor. The processing filter FP may also include a band-pass filter, for example.

[0233] Furthermore, in this embodiment, the low-pass filter 56 includes three low-pass filters, namely, the first low-pass filter 561 to the third low-pass filter 563. However, the low-pass filter 56 may also include two low-pass filters. In this case, the structure and processing can be simplified. Furthermore, the low-pass filter 56 may also include four or more low-pass filters. In this case, the frequency characteristics of the processing filter FP can be more appropriately adjusted.

[0234] and, Figure 1 as well as Figure 2 The functional units shown are merely illustrative of the functional structure, and their specific implementation is not particularly limited. Specifically, it is not necessary to install hardware corresponding to each functional unit independently. A configuration in which a single processor executes a program to implement the functions of multiple functional units is also possible. Furthermore, hardware may partially implement the functions implemented by software in the aforementioned embodiments, and software may partially implement the functions implemented by hardware.

[0235] Furthermore, in order to facilitate understanding of the processing of the control unit 53, Figure 3 The processing units in the flowchart shown are divided according to the main processing contents. Figure 3 The processing units shown in the flowchart are not limited by the division method or name, and can be divided into more processing units according to the processing content, or divided in a way that one processing unit includes more processing. Moreover, the processing order of the flowchart is not limited to the example shown in the figure.

[0236] Furthermore, the control method of the tensile testing machine 1 can be implemented by causing the processor 54 included in the control unit 53 to execute a control program corresponding to the control method of the tensile testing machine 1. Furthermore, the control program can also be pre-recorded in a recording medium that can be recorded readable by a computer. As the recording medium, a magnetic recording medium, an optical recording medium, or a semiconductor memory device can be used. Specifically, portable or fixed recording media such as a floppy disk, an HDD, a compact disk read only memory (CD-ROM), a digital versatile disc (DVD), a Blu-ray (registered trademark) optical disc, a magneto-optical disc, a flash memory, and a card-type recording medium can be listed. Furthermore, the recording medium can also be an internal storage device included in the control unit 53, i.e., a non-volatile storage device such as a RAM, ROM, or HDD. Furthermore, the control program corresponding to the control method of the tensile testing machine 1 can also be stored in a server device, etc., and the control program can be downloaded from the server device to the control unit 53, thereby implementing the control method of the tensile testing machine 1.

Claims

1. A material testing machine, characterized in that: include: Processing filter to remove noise components contained in the detection signal output by the sensor; as well as an adjustment unit that adjusts the frequency characteristics of the processing filter, The adjustment unit receives the detection signal output by the sensor and adjusts the frequency characteristics of the processing filter based on the difference between output signals of two low-pass filters having different frequency characteristics.

2. The material testing machine according to claim 1, characterized in that The output signal of the processing filter is used as a display signal to be displayed on a display.

3. The material testing machine according to claim 1 or 2, characterized in that: Also includes: The first determination unit determines whether the difference between the output signals of the two low-pass filters is greater than a first threshold value. The processing filter comprises a low-pass filter, The adjustment unit reduces a cutoff frequency of the processing filter according to a determination result of the first determination unit.

4. The material testing machine according to claim 3, characterized in that: include: a first low-pass filter having a cutoff frequency of a first frequency; a second low-pass filter having a cutoff frequency that is a second frequency lower than the first frequency; a third low-pass filter having a cutoff frequency that is a third frequency lower than the second frequency; as well as a selection unit that selects the two low-pass filters from among the first low-pass filter, the second low-pass filter, and the third low-pass filter; When the second low-pass filter is set as the processing filter, the selection unit selects the first low-pass filter and the second low-pass filter as the two low-pass filters. The adjustment unit switches the processing filter from the second low-pass filter to the third low-pass filter based on the determination result of the first determination unit.

5. The material testing machine according to claim 1 or 2, characterized in that: Also includes: The second determination unit determines whether the difference between the output signals of the two low-pass filters is less than a second threshold value. The processing filter comprises a low-pass filter, The adjustment unit increases a cutoff frequency of the processing filter according to a determination result of the second determination unit.

6. The material testing machine according to claim 5, characterized in that: include: a first low-pass filter having a cutoff frequency of a first frequency; a second low-pass filter having a cutoff frequency that is a second frequency lower than the first frequency; as well as a third low-pass filter having a cutoff frequency that is a third frequency lower than the second frequency, The material testing machine includes a selection unit that selects the two low-pass filters from the first low-pass filter, the second low-pass filter, and the third low-pass filter. When the third low-pass filter is set as the processing filter, the selection unit selects the first low-pass filter and the third low-pass filter as the two low-pass filters. The adjustment unit switches the processing filter from the third low-pass filter to the second low-pass filter based on a determination result of the second determination unit.

7. A control method for a material testing machine, characterized in that: The material testing machine includes a processing filter, which removes noise components contained in the detection signal output by the sensor. The control method of the material testing machine includes: an adjusting step of adjusting the frequency characteristics of the processing filter, The adjustment step inputs the detection signal output by the sensor and adjusts the frequency characteristics of the processing filter based on the difference between output signals of two low-pass filters having different frequency characteristics.

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