JP2020165701A - Material testing machine and control method for material testing machine - Google Patents

Abstract

To calculate appropriate control compliance that corresponds to material test and enable the feedback control of a servo motor 18 to be exercised with good accuracy.SOLUTION: A material testing machine 1 comprises: a load mechanism 12 for moving a crosshead 10 and adding a test force to a test piece TP; a rotary encoder 20; a response measurement unit; a time width adjustment unit 541 for adjusting a calculation time width; a control compliance calculation unit 542 for calculating control compliance in the calculation time width adjusted by the time width adjustment unit 541; and a feedback control unit 543 for feedback controlling a servo motor 18 on the basis of the calculated control compliance. The time width adjustment unit 541 executes at least one of an adjustment for extending the calculation time width proportionately in correspondence to an increase in the amplitude of noise included in the measured value of response physical quantity and an adjustment for shortening the same proportionately in correspondence to an increase in a time change rate of response physical quantity or the target speed of the crosshead.SELECTED DRAWING: Figure 1

Description

The present invention relates to a material testing machine and a control method for the material testing machine.

Conventionally, in the material test of a material testing machine, feedback control is performed in which an instruction is given to a driving target of a load mechanism that applies a load to the test target and a measured value to be controlled is fed back (for example, Patent Document 1). reference). Patent Document 1 discloses a material testing machine that feedback-controls a load mechanism that applies a test force to a test piece by moving a crosshead.

Japanese Unexamined Patent Publication No. 2005-337812

In a material test as described in Patent Document 1, in feedback control, a ratio of a change in a physical quantity occurring in a test object or a load mechanism and a change in a physical quantity having a high correlation with an indicated value given to the load mechanism is added as a control parameter. There is. In this case, since the material tester can take into account how much change in physical quantity occurs in the test object or load mechanism for how much response change, the accuracy of feedback control of the load mechanism is improved.

Generally, the ratio is calculated based on a measured value measured in a fixed time width. However, if the time width is fixed, the ratio is calculated with the same number of measurements in any material test, and depending on the material test, an appropriate ratio cannot be calculated and feedback control of the load mechanism is performed. The accuracy of is reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable the calculation of an appropriate ratio according to a material test so that feedback control of a load mechanism can be performed with high accuracy.

A first aspect of the present invention includes a load mechanism that applies a load to a test object by a moving member, and a first measurement unit that measures a first physical quantity generated in the test object or the load mechanism in response to the application of the load. , A second measuring unit that measures a second physical quantity that is a response in the feedback control of the load mechanism, a first change amount that indicates a change in the first physical quantity measured by the first measuring unit, and the second measuring unit. A time width adjusting unit that adjusts the time width of the measured values of the first physical quantity and the second physical quantity used for calculating the change amount ratio, which is the ratio of the second change amount indicating the change of the second physical quantity measured by The second physical quantity is based on the change amount ratio calculation unit that calculates the change amount ratio in the time width adjusted by the time width adjusting unit and the change amount ratio calculated by the change amount ratio calculation unit. The load mechanism is feedback-controlled so as to reduce the deviation between the measured value and the target value of the second physical quantity, and the time width adjusting unit includes the second physical quantity with respect to the time width. With respect to a material testing machine, which performs at least one of an adjustment that increases the noise contained in the measured value of the above and an adjustment that decreases the time change rate of the second physical quantity or the target speed of the moving member increases. ..

A second aspect of the present invention includes a load mechanism that applies a load to the test object by a moving member, and a first measurement unit that measures a first physical quantity generated in the test object or the load mechanism in response to the application of the load. , A second measuring unit that measures a second physical quantity that is a response in the feedback control of the load mechanism, a first change amount that indicates a change in the first physical quantity measured by the first measuring unit, and the second measuring unit. A time width adjusting unit that adjusts the time width of the measured values of the first physical quantity and the second physical quantity used for calculating the change amount ratio, which is the ratio of the second change amount indicating the change of the second physical quantity measured by , The change amount ratio calculation unit that calculates the change amount ratio in the time width adjusted by the time width adjustment unit, and the change amount ratio calculated by the change amount ratio calculation unit, and the second physical quantity. A control method for a material testing machine including a control device including a feedback control unit that feedback-controls the load mechanism so as to reduce a deviation between a measured value and a target value of the second physical quantity. The width adjusting unit adjusts the time width to be longer as the noise contained in the measured value of the second physical quantity is larger, and to be shorter as the time change rate of the second physical quantity or the target speed of the moving member is larger. It relates to a method of controlling a material testing machine that at least performs one of the above.

According to the first aspect of the present invention, the time width of the measured value used for calculating the change amount ratio is adjusted to be longer as the noise included in the measured value of the second physical quantity is larger, and the time change of the second physical quantity. By performing at least one of the adjustments that shortens the rate or the target speed of the moving member as it increases, the time width of the measured value used to calculate the change amount ratio is dynamically adjusted to the appropriate width according to the material test. Can be adjusted. Therefore, an appropriate change amount ratio according to the material test can be calculated, and the feedback control of the load mechanism can be performed with high accuracy.

According to the second aspect of the present invention, the same effect as that of the first aspect of the present invention is obtained.

It is a figure which shows typically the structure of the material tester of this embodiment. It is a block diagram which shows the control system of the feedback control of a load mechanism. It is a graph which shows the relationship between the calculated time width and "V" in the formula (2). It is the measurement data of the response physical quantity. It is the measurement data of the response physical quantity. It is a flowchart which shows the operation of a control device. It is the measurement data of the compression test.

[1. Material tester configuration]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing a configuration of a material testing machine 1 according to the present embodiment.
The material testing machine 1 is a testing machine that executes material tests such as a tensile test, a compression test, and a bending test to test the mechanical properties of the test piece TP to be tested. The test targets are various materials, industrial products, parts or members of the industrial products, and the test piece TP is prepared based on a predetermined standard for material testing.

As shown in FIG. 1, the material testing machine 1 includes a testing machine main body 2 that applies a test force F as a load to a test piece TP to perform a material test, and a control unit 4 that controls a material testing operation by the testing machine main body 2. And. Further, the material testing machine 1 includes an extensometer 90 used for measuring the strain of the test piece TP. The extensometer 90 is an automatic extensometer that grips and releases the test piece TP without the manual work of the user, and holds the test piece TP and displaces the test piece TP together with the upper arm 92 and the lower arm 93. And a strain gauge 91 for detecting the displacement of the upper arm 92 and the lower arm 93. The strain gauge 91 is a sensor that measures the elongation amount of the test piece TP and outputs the elongation amount measurement signal A2 to the control device 30.

[2. Testing machine body configuration]
The testing machine main body 2 can move along the table 6, a pair of screw rods 8 and 9 rotatably erected on the table 6 in a vertical direction, and these screw rods 8 and 9. A crosshead 10, a load mechanism 12 for moving the crosshead 10 to give a test force F to the test piece TP, and a load cell 14 are provided. The crosshead 10 corresponds to an example of the "moving member" of the present invention. The load cell 14 is a sensor that measures the test force F, which is the load applied to the test piece TP, and outputs the test force measurement signal A1. The testing machine main body 2 may be configured to have one screw paddle.

The pair of screw paddles 8 and 9 are made of ball screws, and the crosshead 10 is connected to each of the screw paddles 8 and 9 via nuts (not shown). The load mechanism 12 includes worm reducers 16 and 17 connected to the lower ends of the screw paddles 8 and 9, a servomotor 18 connected to each worm reducer 16 and 17, and a rotary encoder 20. The rotary encoder 20 is a sensor that measures the rotation amount Tr of the servomotor 18 and outputs the rotation amount measurement signal A3 of the number of pulses corresponding to the rotation amount Tr to the signal input / output unit 40.
Then, the load mechanism 12 transmits the rotation of the servomotor 18 to the pair of screw paddles 8 and 9 via the worm reducers 16 and 17, and the screw paddles 8 and 9 rotate in synchronization with the cross head. 10 moves up and down along the screw paddles 8 and 9.

The crosshead 10 is provided with an upper grip 21 for gripping the upper end of the test piece TP, and the table 6 is provided with a lower grip 22 for gripping the lower end of the test piece TP. .. The testing machine main body 2 is controlled by the control device 30 in a state where, for example, during a tensile test, the upper end of the test piece TP is gripped by the upper gripper 21 and the lower end of the test piece TP is gripped by the lower gripper 22. As a result, the test piece TP is given a test force F by raising the crosshead 10. For example, during a compression test, the testing machine main body 2 is controlled by the control device 30 with the upper end of the test piece TP gripped by the upper gripper 21 and the lower end of the test piece TP held by the lower gripper 22. As a result, the test piece TP is given a test force F by lowering the crosshead 10. The distance between the upper gripping tool 21 and the lower gripping tool 22 is changed according to the vertical slide of the upper gripping tool 21.

[3. Control unit configuration]
The control unit 4 includes a control device 30, a display device 32, and a test program execution device 34.

The control device 30 is a device that centrally controls the testing machine main body 2, and is connected to the testing machine main body 2 so as to be able to transmit and receive signals. The signals received from the tester main body 2 are the test force measurement signal A1 output by the load cell 14, the elongation amount measurement signal A2 output by the extensometer 90, the rotation amount measurement signal A3 output by the rotary encoder 20, and for control and testing. It is an appropriate signal that is required.

The display device 32 is a device that displays various information based on the signal input from the control device 30, and for example, the control device 30 is applied to the test piece TP based on the test force measurement signal A1 during the material test. The position of the cross head 10 and the like are displayed on the display device 32 based on the measured value of the test force F and the rotation amount measurement signal A3.

The test program execution device 34 receives user operations such as setting operations of various setting parameters such as test conditions for material tests and execution instruction operations, and outputs data to the control device 30 and analyzes data such as measured values of test force F. It is a device equipped with a function to perform. The test program execution device 34 includes a computer, which includes a processor such as a CPU and MPU, a memory device such as a ROM and a RAM, a storage device such as an HDD and an SSD, a control device 30, and various peripheral devices. It is provided with an interface circuit for connection. Then, the processor executes a material test program which is a computer program stored in a memory device or a storage device to realize the above-mentioned various functions.

Next, the control device 30 will be described in detail.
As shown in FIG. 1, the control device 30 includes a signal input / output unit 40 and a control circuit unit 50.

The signal input / output unit 40 constitutes an input / output interface circuit for transmitting and receiving signals to and from the testing machine main body 2. In the present embodiment, the first sensor amplifier 41, the second sensor amplifier 42, and the counter circuit It has 43 and a servo amplifier 44.

The first sensor amplifier 41 is an amplifier that amplifies the test force measurement signal A1 output from the load cell 14 and inputs it to the control circuit unit 50.

The second sensor amplifier 42 is an amplifier that amplifies the elongation amount measurement signal A2 output by the elongation meter 90 and inputs it to the control circuit unit 50.

The counter circuit 43 counts the number of pulses of the rotation amount measurement signal A3 output by the rotary encoder 20 and outputs the count value A4 to the control circuit unit 50 as a digital signal. The count value A4 indicates the rotation amount Tr of the servomotor 18 with reference to the start of the material test. The rotation amount Tr of the servomotor 18 based on the start of the material test corresponds to the moving distance of the crosshead 10 based on the position at the start of the material test. The rotary encoder 20 and the counter circuit 43 constitute a rotation amount measuring unit 60, and the rotation amount measuring unit 60 corresponds to an example of the "first measuring unit" of the present invention. Further, the rotation amount Tr of the servomotor 18 corresponds to an example of the "first physical quantity" of the present invention.

The rotation amount measuring unit 60 may be configured to include an encoder mounted on at least one of the screw paddles 8 and 9 instead of the rotary encoder 20. In the case of this configuration, the encoder generates a signal that outputs one pulse each time at least one of the attached screw paddles 8 and 9 rotates by a predetermined angle, and outputs the signal to the counter circuit 43.

The servo amplifier 44 is a device that controls the servomotor 18 under the control of the control circuit unit 50.

The control circuit unit 50 includes a communication unit 52, a control unit 54, and a storage unit 56.
The control circuit unit 50 communicates with a processor such as a CPU or MPU, a memory device such as a ROM or RAM, a storage device such as an HDD or SSD, an interface circuit between the signal input / output unit 40, and a test program execution device 34. A computer including a communication device, a display control circuit for controlling the display device 32, and various electronic circuits, and a processor executes a computer program stored in a memory device or a storage device to control a control unit. Each of the 54 functional units is realized. Further, an A / D converter is provided in the interface circuit of the signal input / output unit 40, and the test force measurement signal A1 of the analog signal is converted into a digital signal by the A / D converter.
The control circuit unit 50 is not limited to a computer, and may be configured by one or a plurality of appropriate circuits such as integrated circuits such as IC chips and LSIs.

The communication unit 52 communicates with the test program execution device 34, and receives settings of material test conditions, set values of various setting parameters, material test execution instructions, interruption instructions, and the like from the test program execution device 34. Further, the communication unit 52 transmits, for example, the measured value of the test force F based on the test force measurement signal A1 to the test program execution device 34 at an appropriate timing.

The storage unit 56 is composed of a memory device and stores the target data 561.
The target data 561 is time-series data showing the temporal variation of the target value such as the test force F in the material test. The target data 561 is mutably stored by the control circuit unit 50 according to a user setting operation for the test program execution device 34.

The control unit 54 is a functional unit that feedback-controls the servomotor 18 as the load mechanism 12 of the testing machine main body 2 to execute the process related to the material test. Here, before explaining each functional unit included in the control unit 54, a control system for feedback control of the servomotor 18 will be described.

[3-1. Control system configuration]
The configuration of the control system that feedback-controls the servomotor 18 will be described with reference to FIG.
FIG. 2 is a block diagram showing a control system for feedback control of the servomotor 18 in the present embodiment. In FIG. 2, t shows the execution timing of the control cycle of the feedback control.

In the feedback control of the load mechanism 12, PID control is performed as shown in FIG. 2, and the rotation amount Tr (t) of the servomotor 18 is determined. Then, in the Fordback control of the servomotor 18, the rotation amount Tr (t) of the servomotor 18 is updated every preset control cycle.

As shown in FIG. 2, the block diagram of the feedback control includes a subtractor 70, a converter 71, and a controller 78. The controller 78 includes a proportional device 72, an integrator 73, a first differentiator 74, a first adder 75, a second adder 76, and a second differentiator 77.

The subtractor 70 calculates the deviation e (t) obtained by subtracting the measurement response physical quantity RPs (t) from the target response physical quantity RPc (t) in each control cycle, and outputs the calculated deviation e (t) to the converter 71. ..

The target response physical quantity RPc indicates a target response physical quantity RP in the material test. The response physical quantity RP is a physical quantity that becomes a response in the feedback control of the servomotor 18, and corresponds to the “second physical quantity” of the present invention. Examples of the response physical quantity RP include a test force F applied to the test piece TP, an elongation amount of the test piece TP, and the like. When the response physical quantity RP is the test force F, the load cell 14 corresponds to the “second measuring unit” of the present invention, and when the response physical quantity RP is the elongation amount of the test piece TP, the elongation meter 90 is the “second measuring unit” of the present invention. Corresponds to "2 measurement unit". Hereinafter, when the load cell 14 and the extensometer 90 are not distinguished, they are collectively referred to as a “response measuring unit”.

The converter 71 multiplies the deviation e (t) output by the subtractor 70 by the control compliance Comp (t) described later, and multiplies the deviation e (t) by the movement amount X (t) (both stroke value) of the crosshead 10. It is converted into the deviation e'(t) corresponding to). The converter 71 inputs the converted deviation e'(t) to the proportional device 72, the integrator 73, and the first differentiator 74.

In the present embodiment, the movement amount X of the crosshead 10 corresponds to the amount of change between the rotation amount Tr of the servomotor 18 at a certain timing and the rotation amount Tr of the servomotor 18 at a timing different from the certain timing. It is the amount of change in the position of the crosshead 10. The movement amount X of the crosshead 10 corresponds to an example of the "first change amount" of the present invention.

The first adder 75 adds the outputs of the proportional device 72, the integrator 73, and the first differentiator 74, and outputs the first addition value K1 (t) to the second adder 76. Further, the second adder 76 adds the initial movement amount U0 to the first addition value K1 (t) output by the first adder 75, and outputs the second addition value K2 (t) to the second differentiator 77. To do.

The second differentiator 77 differentiates the second adder K2 (t) output from the second adder 76, thereby differentiating the movement amount X (t) of the crosshead 10 indicated by the second adder K2 (t). The rotation amount Tr (t) of the servomotor 18 is calculated from the above. Then, in the feedback control shown in FIG. 2, a command signal B1 indicating the rotation amount Tr (t) of the servomotor 18 is output to the servo amplifier 44.

[3-2. Control circuit unit configuration]
The functional block of the control unit 54 will be described with reference to FIG.
The control unit 54 includes a time width adjustment unit 541, a control compliance calculation unit 542, and a feedback control unit 543. The control compliance calculation unit 542 corresponds to an example of the "change amount ratio calculation unit" of the present invention.
Details of the time width adjusting unit 541 will be described later.

The control compliance calculation unit 542 calculates the control compliance Comp. The control compliance Comp is the most correlated with the change in the physical quantity of the feedback target generated in the test piece TP or the load mechanism 12 and the indicated value given to the drive target of the load mechanism 12 (rotation amount Tr of the servomotor 18 in this embodiment). It is the ratio to the change of high physical quantity. In the present embodiment, the control compliance calculation unit 542 calculates the control compliance Comp, which is the ratio of the movement amount X of the crosshead 10 and the change amount of the response physical quantity RP in the calculation time width described later. In the case of FIG. 2, the control compliance Comp is the ratio of the movement amount X of the crosshead 10 and the change amount of the elongation amount of the test piece TP in the calculation time width described later. The control compliance Comp corresponds to an example of the "change amount ratio" of the present invention.

The control compliance calculation unit 542 calculates the control compliance Comp based on, for example, the following equation (1).
Comp (t) = Slop1 (t) / Slop2 (t) ... (1)
In equation (1), t is the execution timing of the control cycle. In addition, Comp (t) indicates the control compliance in each control cycle. Further, Slop1 (t) indicates the first slope calculated by the control compliance calculation unit 542 in each control cycle. Further, Slop2 (t) indicates the second slope calculated by the control compliance calculation unit 542 in each control cycle.

The first inclination Slop1 will be described.
When the control cycle of the feedback control arrives, the control compliance calculation unit 542 is a slope of an approximate straight line representing the relationship between the rotation amount Tr of the servomotor 18 and the time in the calculated time width adjusted by the time width adjustment unit 541. 1 Slope Slop1 is calculated. The calculated time width is the time width of the measured values of the response physical quantity RP and the rotation amount Tr of the servomotor 18 used by the control compliance calculation unit 542 to calculate the control compliance Comp. In the present embodiment, the calculated time width is the time width from the time when the control cycle arrives to a certain time toward the past. The time width adjusting unit 541 adjusts the calculated time width by changing the certain time. The calculated time width corresponds to the "time width" of the present invention. The control compliance calculation unit 542 calculates the movement amount X of the crosshead 10 per unit time in the calculation time width based on the measured value of the rotation amount Tr of the servomotor 18 in the calculation time width.

The control compliance calculation unit 542 sequentially acquires the measured value of the rotation amount Tr of the servomotor 18 based on the count value A4 input from the counter circuit 43. Then, when the control cycle arrives, the control compliance calculation unit 542 revolves between the measured value and the time based on the measured value of the rotation amount Tr of the servomotor 18 in the calculated time width adjusted by the time width adjusting unit 541. The approximate straight line representing the above is calculated, and the slope of the calculated approximate straight line is calculated as the first slope Slop1. The control compliance calculation unit 542 calculates the approximate straight line and the first slope Slop1 by, for example, the least squares method or the principal component analysis.

Next, the second slope Slop2 will be described.
When the control cycle of feedback control arrives, the control compliance calculation unit 542 has a second slope of an approximate straight line representing the relationship between the measured value of the response physical quantity RP and the time in the calculated time width adjusted by the time width adjustment unit 541. The slope Slop2 is calculated. That is, the control compliance calculation unit 542 calculates the amount of change in the response physical quantity RP per unit time in the calculated time width based on the measured value of the response physical quantity RP in the calculated time width adjusted by the time width adjustment unit 541. .. The calculated time width when calculating the first slope Slop1 and the calculated time width when calculating the second slope Slop2 are the same.

When the response physical quantity RP is the elongation amount of the test piece TP, the control compliance calculation unit 542 calculates the elongation amount of the test piece TP from the elongation amount measurement signal A2 input from the elongation meter 90 via the second sensor amplifier 42. Acquire sequentially. When the control cycle arrives, the control compliance calculation unit 542 is an approximate straight line representing the relationship between the elongation amount and the time based on the elongation amount of the test piece TP acquired in the calculated time width adjusted by the time width adjustment unit 541. Is calculated, and the slope of the calculated approximate straight line is calculated as the second slope Slop2. The control compliance calculation unit 542 calculates an approximate straight line and a second slope Slop2 by, for example, the least squares method or principal component analysis.

The feedback control unit 543 executes feedback control of the servomotor 18. In each control cycle, the feedback control unit 543 multiplies the deviation e (t) between the target response physical quantity RPc (t) and the measurement response physical quantity RPs (t) by the control compliance Comp calculated by the control compliance calculation unit 542. e'(t) is calculated. Then, the feedback control unit 543 rotates the servomotor 18 to reduce the deviation e (t) between the measured response physical quantity RPs (t) and the target response physical quantity RPc (t) based on the calculated deviation e ′ (t). The quantity Tr (t) is calculated, and the command signal B1 indicating the rotation amount Tr (t) is output to the servo amplifier 44.

[4. Calculation time width adjustment]
Next, the time width adjusting unit 541 will be described.
The time width adjusting unit 541 adjusts the calculated time width by the following equation (2).

Calculated time width = TW x (V) ^ b ... (2)

In the formula (2), "TW" is the maximum adjustable time width which is the upper limit of the calculated time width which can be adjusted for the longest time by the time width adjusting unit 541. The maximum adjustable time width is obtained as follows before the start of the material test and is given to the material testing machine 1 in advance as data.

In the present embodiment, the maximum adjustable time width is a calculated time width calculated based on the measured value of the response physical quantity RP when the crosshead 10 is moving at the lowest speed among the speeds at which the crosshead 10 can move. The change in the response physical quantity RP, that is, the shortest calculation time width in which the second gradient Slop2 can be calculated, is shown without being buried in the amplitude of the noise and the amount of noise included in the measured value. The maximum adjustable time width of the present embodiment is half of the standard deviation of the measured value of the response physical quantity RP when the crosshead 10 is moving at the minimum speed, and is the time when the response physical quantity RP changes. There is. This "half" is appropriately determined by prior tests and simulations.

For example, the response physical quantity RP is the elongation amount of the test piece TP, the minimum velocity is "1 (μm / sec)", and the standard deviation of the measured value of the elongation amount at the minimum velocity is "8000 (μm)". In this case, the maximum adjustable time width is "4000 (msec)". This can be done by using the measured value of the elongation amount of the test piece TP measured between "4000 (msec)" even when the crosshead 10 moves at a moving speed of "1 (μm / sec)". It shows that the slope Slop2 can be calculated.

In the equation (2), the time change rate of the response physical quantity RP in a predetermined period or the target speed of the crosshead 10 in the control cycle is substituted for "V". The time width adjusting unit 541 acquires the time change rate of the response physical quantity RP in a predetermined period or the target speed of the crosshead 10 by calculation or the like, and substitutes it into “V” in the equation (2) to adjust the calculated time width. To determine.

In the formula (2), "b", which is an index of "V", is a coefficient for setting the shortest calculation time width in which the control compliance calculation unit 542 can adjust the calculation time width.

In the present embodiment, "b" in the formula (2) is obtained as follows.
That is, for "b", the maximum speed at which the crosshead 10 can move is substituted for "V" in the equation (2), and the second inclination Slop2 at the maximum speed of the crosshead 10 is set in the calculated time width of the equation (2). It is calculated by substituting the shortest calculation time width that can be calculated and substituting the adjustable maximum time width calculated as described above into "TW".

For example, assume that the maximum time width is "4000 (msec)", the maximum speed of the crosshead 10 is "16000 (μm / sec)", and the minimum calculated time width is "10 (msec)". .. In this case, "b" in the equation (2) is obtained as "-0.5" by the calculation of "10 (msec) = 4000 (msec) x 160000 (μm / sec) ^ b".

The shortest calculation time width assigned to the right side of the equation (2) when calculating "b" is such that the number of measurements is not insufficient even when the crosshead 10 is moving at the maximum speed. This is the shortest calculation time width in which the second slope Slop2 can be calculated. The shortest calculation time width is appropriately determined in advance by a preliminary test, simulation, or the like.

FIG. 3 is a graph showing the relationship between the calculated time width in the equation (2) and “V”.
In FIG. 3, the vertical axis is set to the calculated time width, and the horizontal axis is set to “V” in the equation (2). In FIG. 3, the response physical quantity RP is used as the elongation amount of the test piece TP. Therefore, in FIG. 3, the unit on the vertical axis is set to “msec” and the unit on the horizontal axis is set to “μm / sec”.
FIG. 3 shows a graph in the case where the maximum adjustable time width is “4000 (msec)” and “b” is −0.5 in the equation (2).

According to the equation (2) in which the maximum adjustable time width calculated in this way and "b" are substituted, the time width adjusting unit 541 appropriately sets a predetermined period with respect to "V" in the equation (2). The calculated time width is adjusted by substituting the time change rate of the response physical quantity RP in the above or the target speed of the crosshead 10 in the control cycle. Therefore, by obtaining the calculated time width by the equation (2), the time width adjusting unit 541 does not adjust the calculated time width longer than the maximum adjustable time width, and the crosshead 10 has the highest speed. 2 The slope Slop2 is not adjusted to be shorter than the shortest calculation time width that can be calculated.

As described above, the maximum adjustable time width is included in the measured value based on the measured value of the response physical quantity RP when the crosshead 10 is moving at the lowest speed among the speeds at which the crosshead 10 can move. The change in the response physical quantity RP without being buried in the amplitude of the noise and the amount of noise, that is, the shortest calculation time width in which the second gradient Slop2 can be calculated is shown. Therefore, the time width adjusting unit 541 does not adjust the calculated time width longer than the maximum adjustable time width by adjusting the calculated time width according to the equation (2). Therefore, the control compliance calculation unit 542 does not calculate the control compliance Comp in a time width unnecessarily longer than the maximum adjustable time width. Further, the control compliance calculation unit 542 adjusts so that the slower the moving speed of the crosshead 10 is, the longer the calculation time width is. Therefore, the larger the amplitude of noise is relative to the change in the response physical quantity RP. , The control compliance Comp can be calculated by sufficiently reducing the influence of noise contained in the measured value of the response physical quantity RP. Therefore, when the time width adjusting unit 541 adjusts the calculated time width based on the equation (2), the control compliance calculation unit 542 may have a case where the noise amplitude is relatively large with respect to the change amount of the response physical quantity RP. Even when the amount of noise is large, the control compliance Comp in which the influence of the noise is reduced can be calculated with a necessary and sufficient number of measurements.

Further, since the second inclination Slop2 cannot be smaller than the shortest calculation time width that can be calculated at the maximum speed of the crosshead 10, the calculation time width is extremely large even when the change in the response physical quantity RP per unit time is large. The control compliance Comp can be calculated appropriately without shortening.

As described above, this equation (2) is adjusted so that the calculated time width becomes smaller as the time change rate of the response physical quantity RP in a predetermined period or the target speed of the crosshead 10 in the control cycle increases. The formula is shown. In addition to this, this equation (2) is also an equation adjusted so that the larger the amplitude of noise included in the measured value of the response physical quantity RP, or the larger the amount of noise, the longer the calculation time width. This is because "TM" is substituted with a value based on the standard deviation of the measured value of the response physical quantity RP at the minimum speed of the crosshead 10 as the adjustable maximum time width.

The accuracy of the second slope Slop2 calculated by the control compliance calculation unit 542 with the calculation time width adjusted based on the equation (2) will be described below with reference to FIGS. 4 and 5. The measurement data shown in FIGS. 4 and 5 show the measurement data in the calculated time width based on the formula (2) in which "TM" is set to 4000 (msec) and "b" is set to -0.5. There is.

FIG. 4 shows measurement data of the response physical quantity RP when the crosshead 10 is moved at a target speed of 9 (μm / sec) in the calculated time width corresponding to 9 (μm / sec) on the horizontal axis of FIG. is there. The measurement data of the response physical quantity RP shown in FIG. 4 is the measurement data showing the elongation amount of the test piece TP measured by the extensometer 90. The calculated time width corresponding to 9 (μm / sec) on the horizontal axis of FIG. 3 is 1333 (msec).

In FIG. 4, the vertical axis is set to the amount of elongation (μm), and the horizontal axis is set to the time (sec). In FIG. 4, the graph Gf4-1 shown by the solid line is the measurement data of the response physical quantity RP, and the graph Gf4-2 shown by the alternate long and short dash line shows the target speed of the crosshead 10. The graph Gf4-3 shown by the dotted line is an approximate straight line calculated by the least squares method based on the graph Gf4-1 shown by the solid line.

In FIG. 4, the slope of the straight line is the second slope Slop2. The graph Gf4-2 shown by the alternate long and short dash line is the target speed of the crosshead 10. Therefore, the slope of the graph Gf4-2 is the true value of the second slope Slop2 calculated in the calculation time width corresponding to 9 (μm / sec). As is clear from the comparison between the graph Gf4-2 and the graph Gf4-3, the slopes of both are about 8778 (μm / sec), which are almost the same. This indicates that the second slope Slop2 is appropriately calculated by the measurement data of the response physical quantity RP in the calculation time width corresponding to 9 (μm / sec).

FIG. 5 is measurement data of the response physical quantity RP when the crosshead 10 is moved at a target speed of 70 μ / sec in the calculated time width corresponding to the horizontal axis of 70 μ / sec in FIG. The measurement data of the response physical quantity RP shown in FIG. 5 is the measurement data showing the elongation amount of the test piece TP measured by the extensometer 90. The calculated time width corresponding to 70 (μm / sec) on the horizontal axis of FIG. 3 is 478 (msec).

In FIG. 5, the vertical axis is set to the amount of elongation (μm), and the horizontal axis is set to the time (sec). In FIG. 5, the graph Gf5-1 shown by the solid line is the measurement data of the response physical quantity RP, and the graph Gf5-2 shown by the alternate long and short dash line shows the target speed of the crosshead 10. The graph Gf5-3 shown by the dotted line is an approximate straight line calculated by the least squares method based on the graph Gf5-1 shown by the solid line.

In FIG. 5, the slope of the straight line is the second slope Slop2. The graph Gf5-2 shown by the alternate long and short dash line is the target speed of the crosshead 10. Therefore, the slope of the graph Gf5-2 is the true value of the second slope Slop2 calculated in the calculation time width corresponding to 70 (μ / sec). As is clear from the comparison between the graph Gf5-2 and the graph Gf5-3, the slopes of both are about 69942 (μm / sec), which are almost the same. This indicates that the second slope Slop2 is appropriately calculated by the measurement data of the response physical quantity RP in the calculation time width corresponding to 70 (μm / sec).

As shown from the measurement data of FIGS. 4 and 5, the second slope Slop2 is appropriate even if the calculated time width is adjusted according to the time change rate of the response physical quantity RP or the target speed of the crosshead 10. Can be calculated. The control compliance calculation unit 542 calculates the first slope Slop1 with the calculation time width for which the second slope Slop2 is calculated. Therefore, the fact that the second slope Slop2 can be calculated appropriately indicates that the first slope Slop1 can also be calculated appropriately, and the control compliance Comp can be calculated accurately according to the calculation time width.

[5. Control device operation]
Next, the operation of the material testing machine 1 will be described.
FIG. 6 is a flowchart showing the operation of the material testing machine 1, and in particular, the flowchart showing the operation related to the feedback control of the servomotor 18.

In the description of the flowchart shown in FIG. 6, the feedback control of the servomotor 18 will be described. During the execution of the material test, the control device 30 executes the operation of the flowchart shown in FIG. 6 at predetermined control cycles to feedback-control the servomotor 18.

When the control cycle arrives, the time width adjusting unit 541 of the control unit 54 of the control device 30 sets the time change rate of the response physical quantity RP in a predetermined period or the target speed of the crosshead 10 to "V" in the equation (2). Substitute and adjust the calculated time width (step SA1). For example, the time width adjusting unit 541 calculates the time change rate of the measured value of the response physical quantity RP in a predetermined period toward the past from the incoming control cycle and substitutes it in step SA1. Further, for example, the time width adjusting unit 541 calculates the target speed of the crosshead 10 from the target waveform of the target data 561 and substitutes it in step SA1.

Next, the control compliance calculation unit 542 calculates the first inclination Slop1 (t) based on the rotation amount Tr of the servomotor 18 measured with the calculated time width adjusted by the time width adjustment unit 541 in step SA1 (step). SA2).

Next, the control compliance calculation unit 542 calculates the second slope Slop2 (t) based on the response physical quantity RP measured with the calculated time width adjusted by the time width adjustment unit 541 in step SA1 (step SA3).

The processing order of step SA2 and step SA3 is not limited to this order, and may be reversed or simultaneous.

Next, the control compliance calculation unit 542 calculates the control compliance Comp (t) (step SA4).

Next, the feedback control unit 543 calculates the deviation e (t) by subtracting the measurement response physical quantity RPs (t) from the target response physical quantity RPc (t) (step SA5).

Then, the feedback control unit 543 calculates the deviation e'(t) by multiplying the deviation e (t) by the control compliance Comp calculated in step SA5 (step SA6).

Next, the feedback control unit 543 calculates the rotation amount Tr (t) of the servomotor 18 that matches the target response physical quantity RPc (t) and the measurement response physical quantity RPs (t) based on the deviation e'(t). (Step SA7).

Then, the feedback control unit 543 outputs a command signal B1 indicating the calculated rotation amount Tr (t) to the servo amplifier 46 (step SA8).

[6. Material test accuracy]
FIG. 7 is a diagram showing measurement data of the compression test. The compression test may be performed with the jig shown in FIG. 1 or with a jig dedicated to the compression test such as a pressure plate.
In FIG. 7, the vertical axis is set to the test force (N: Newton) and the horizontal axis is set to the time (sec).

In the compression test of the measurement data shown in FIG. 7, the crosshead 10 is moved at a target speed of 50 (mm / sec) to increase the test force F applied to the test piece TP to 2000 N, and then the test force F is applied. It is set as a test condition to keep it at 2000N.

In FIG. 7, graph Gf7-1 is measurement data when the control compliance Comp is calculated with a fixed calculation time width and the servomotor 18 is feedback-controlled. On the other hand, in FIG. 7, in the graph Gf7-2, 50 (mm / sec) is substituted for “V” in the equation (2), and the control compliance Comp is calculated with the calculation time width corresponding to 50 (mm / sec). This is the measurement data when the servomotor 18 is feedback-controlled. The fixed calculation time width in the graph Gf7-1 is longer than the calculation time width corresponding to 50 (mm / sec) in the graph Gf7-2.

As shown in FIG. 7, when the calculated time width is fixed, immediately after holding the test force F, the characteristics of the test force F vibrate with reference to 2000 (N), and a stable hold of the test force F is maintained. I can't do it. This is because the calculation time range of the control compliance Comp is long, and the control compliance calculation unit 542 calculates the control compliance Comp that deviates from the actual control compliance Comp, and the feedback control of the servomotor 18 cannot be performed accurately. I'm showing.

On the other hand, in the graph Gf7-2, the vibration immediately after holding the test force F is reduced as compared with the graph Gf7-1. This is because the control compliance calculation unit 542 calculates the control compliance Comp with the calculation time width corresponding to 50 (mm / sec), so that the control compliance Comp that does not deviate from the actual control compliance Comp can be calculated. It shows that the feedback control of the servomotor 18 is performed with high accuracy.

[7. Other embodiments]
It should be noted that the above-described embodiment is merely an example of one aspect of the present invention, and can be arbitrarily modified and applied without departing from the spirit of the present invention.

In the above-described embodiment, the time width adjusting unit 541 has a configuration in which the calculated time width is adjusted by the equation (2). However, the equation referred to when the time width adjusting unit 541 adjusts the calculated time width is not limited to the equation (2). The formula referred to by the time width adjusting unit 541 has a longer calculated time width as the noise vibration included in the measured value of the response physical quantity RP is larger or the amount of noise is larger, and the target speed or response of the crosshead 10 is increased. The formula may be such that the calculated time width becomes shorter as the time change rate of the physical quantity RP increases.

Further, in the above-described embodiment, the control compliance calculation unit 542 calculates the ratio of the first inclination Slop1 and the second inclination Slop2 as the change amount ratio, but the calculation method of the control compliance Comp is not limited to this. .. Any calculation method may be used to calculate the control compliance Comp based on the measured value in the calculated time width adjusted by the time width adjusting unit 541. For example, the response physical quantity RP measured in this calculated time width and the rotation of the servomotor 18 The quantity Tr may be calculated by the method of least squares.

In the above-described embodiment, the material tester 1 that performs the compression test is shown in the measurement data of FIG. 7, but in the present invention, the test force F is applied to the test piece TP to measure the change in the physical quantity of the test piece TP. It can be widely applied to material testing machines. For example, the present invention can be applied to a material testing machine that performs a tensile test, a bending test, a peeling test, and the like. As the jig fixed to the tester main body 2 of the test piece TP, an appropriate jig is adopted according to the test type.

For example, in the above embodiment, as shown in the block diagram shown in FIG. 2, feedback control of the servomotor 18 is performed by PID control. As another configuration, the feedback control of the servomotor 18 may be performed by general PD control.

For example, in the above embodiment, the test force F and the elongation amount of the test piece TP are exemplified as the response physical quantity RP, but torque, pressure, displacement, or the like may be used. Further, as the first physical quantity of the present invention, the rotation amount Tr of the servomotor 18 is exemplified, and as the first change amount of the present invention, the movement amount of the crosshead 10 is exemplified, but the present invention is not limited thereto. For example, the first change amount of the present invention may be the change amount of the elongation amount of the test piece TP, and in this case, the first physical quantity of the present invention is the elongation amount of the test piece TP.

For example, in the above embodiment, the servomotor 18 is used as the drive source of the load mechanism 12, but another drive source such as a hydraulic source may be used. In this case, the output to the control target in the block diagram of FIG. 2 is set to a physical quantity according to the drive source.

For example, in the above-described embodiment, the functional block shown in FIG. 1 is a schematic diagram showing components classified according to main processing contents in order to facilitate understanding of the present invention, and is shown according to the processing contents. , Can be classified into more components. It can also be categorized so that one component performs more processing.

For example, the step unit of the operation shown in FIG. 6 is divided according to the main processing contents in order to facilitate understanding of the operation of each part of the material testing machine 1, and the method and name of the division of the processing unit. Does not limit the present invention. It may be divided into more step units depending on the processing content. Further, one step unit may be divided so as to include more processes. Further, the order of the steps may be appropriately changed as long as it does not interfere with the gist of the present invention.

[7. Summary of embodiments]

As described above, the material testing machine 1 includes a load mechanism 12 that applies a test force F to the test piece TP by the crosshead 10, a rotation amount measuring unit 60 that measures the rotation angle of the servomotor 18, and a response physical quantity. A response measurement unit that measures RP, a time width adjustment unit 541 that adjusts the calculation time width, a control compliance calculation unit 542 that calculates a control compliance Comp in the calculation time width adjusted by the time width adjustment unit 541, and a control compliance calculation unit. A feedback control unit 543 that feedback-controls the servomotor 18 so as to reduce the deviation between the measurement response physical quantity RPs and the target response physical quantity RPc based on the control compliance Comp calculated by the unit 542. The time width adjustment unit 541 adjusts the calculated time width to be longer as the amplitude of noise included in the measured value of the response physical quantity RP is larger or as the amount of noise is larger, and the time change rate or crosshead of the response physical quantity RP. At least one of the adjustments that shortens the target speed of 10 is performed.

According to this configuration, the calculated time width is adjusted to be longer as the amplitude of noise contained in the measured value of the response physical quantity RP is larger or as the amount of noise is larger, and the time change rate or crosshead of the response physical quantity RP. The calculated time width can be dynamically adjusted to an appropriate width according to the material test by executing at least one of the adjustments that shortens the target speed of 10 as it becomes larger. Therefore, an appropriate control compliance Comp can be calculated according to the material test, and the feedback control of the servomotor 18 can be performed with high accuracy.

Further, the time width adjusting unit 541 is set to be equal to or less than the maximum adjustable time width calculated based on the noise amplitude or the amount of noise included in the measured value of the response physical quantity RP when the moving speed of the crosshead 10 is the minimum speed. Adjust the calculation time width so that

According to this configuration, the control compliance calculation unit 542 does not calculate the control compliance Comp in a time width unnecessarily longer than the maximum adjustable time width when the crosshead 10 is moving at the minimum speed. Further, since the control compliance calculation unit 542 adjusts so that the calculation time width becomes longer as the moving speed of the cross head 10 is slower, the noise amplitude is relatively large with respect to the change amount of the response physical quantity RP. However, it is possible to calculate the control compliance Comp in which the influence of noise included in the measured value of the response physical quantity RP is sufficiently reduced. Therefore, by adjusting the calculation time width so that the time width adjustment unit 541 is equal to or less than the maximum adjustable time width, the control compliance calculation unit 542 increases the noise amplitude relative to the change amount of the response physical quantity RP. Even when the amount of noise is large or the amount of noise is large, the control compliance Comp in which the influence of the noise is reduced can be calculated with a necessary and sufficient number of measurements.

The time width adjusting unit 541 adjusts the calculated time width so that the control compliance Comp is equal to or greater than the shortest calculated time width that can be calculated when the moving speed of the crosshead 10 is the maximum speed.

According to this configuration, the calculated calculation time width to be adjusted is not shorter than the shortest calculated time width that can be calculated at the maximum speed of the crosshead 10, so that the calculation is performed even when the displacement of the measured value of the response physical quantity RP is large. The control compliance Comp can be calculated appropriately without shortening the time width extremely.

The control compliance calculation unit 542 calculates the first slope Slop1 in the calculated time width adjusted by the time width adjustment unit 541, calculates the second slope Slop2 in the calculated time width adjusted by the time width adjustment unit 541, and calculates the first slope Slop2. The ratio of Slop1 to the second slope Slop2 is calculated as the control compliance Comp.

According to this configuration, the first slope Slop1 and the second slope Slop2 are used as the calculation parameters of the control compliance Comp. Therefore, the calculation parameter of the control compliance Comp is a parameter in which the fluctuation of the measured value due to noise is removed, and is a parameter related to the change amount of the movement amount X of the crosshead 10 and the elongation amount P of the test piece TP. Can be done. Therefore, by calculating the ratio of the first slope Slop1 and the second slope Slop2 as the control compliance Comp, the fluctuation of the measured value due to noise is not added to the calculation of the control compliance Comp, and the control compliance Comp is calculated accurately. it can. Therefore, the material testing machine 1 can calculate the control compliance Comp with high accuracy, and the feedback control of the servomotor 18 can be performed with higher accuracy.

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

(Section 1)
The material testing machine according to one aspect includes a load mechanism that applies a load to the test object by a moving member, and a first measuring unit that measures a first physical quantity generated in the test object or the load mechanism in response to the application of the load. , A second measuring unit that measures a second physical quantity that is a response in the feedback control of the load mechanism, a first change amount that indicates a change in the first physical quantity measured by the first measuring unit, and the second measuring unit. A time width adjusting unit that adjusts the time width of the measured values of the first physical quantity and the second physical quantity used for calculating the change amount ratio, which is the ratio of the second change amount indicating the change of the second physical quantity measured by The second physical quantity is based on the change amount ratio calculation unit that calculates the change amount ratio in the time width adjusted by the time width adjusting unit and the change amount ratio calculated by the change amount ratio calculation unit. The load mechanism is feedback-controlled so as to reduce the deviation between the measured value and the target value of the second physical quantity, and the time width adjusting unit includes the second physical quantity with respect to the time width. At least one of an adjustment that lengthens as the noise contained in the measured value of is larger and an adjustment that shortens the time change rate of the second physical quantity or the target speed of the moving member increases is executed.

According to the material testing machine described in the first item, the time width of the measured value used for calculating the change amount ratio is adjusted to be longer as the noise contained in the measured value of the second physical quantity is larger, and the second physical quantity is adjusted. By at least performing either the time change rate or the adjustment that shortens as the target speed of the moving member increases, the time width of the measured value used to calculate the change amount ratio is moved to an appropriate width according to the material test. Can be adjusted. Therefore, an appropriate change amount ratio according to the material test can be calculated, and the feedback control of the load mechanism can be performed with high accuracy.

(Section 2)
In the material testing machine according to the first item, the time width adjusting unit has the time width calculated based on the noise included in the measured value of the second physical quantity when the moving speed of the moving member is the minimum speed. The time width is adjusted so as to be as follows.

According to the material testing machine described in the second item, even when the noise is relatively large with respect to the change in the measured value of the second physical quantity, the time adjusting unit affects the influence of the noise with a necessary and sufficient number of measurements. The time width can be adjusted so that the reduced change ratio can be calculated.

(Section 3)
In the material testing machine according to the first or second paragraph, the time width adjusting unit is set to be equal to or greater than the shortest time width that can calculate the change amount ratio when the moving speed of the moving member is the maximum speed. The time width is adjusted so as to be.

According to the material testing machine described in the third item, even when the displacement of the response physical quantity is large, the time width is not extremely shortened, so that the change amount ratio can be calculated appropriately.

(Section 4)
In the material testing machine according to any one of the items 1 to 3, the change amount ratio calculation unit is the first measurement unit measured by the first measurement unit in the time width adjusted by the time width adjustment unit. The first slope, which is the slope of an approximate straight line representing the relationship between one physical quantity and time, is calculated, and the second physical quantity and time measured by the second measuring unit in the time width adjusted by the time width adjusting unit. The second slope, which is the slope of the approximate straight line representing the relationship, is calculated, and the ratio of the first slope to the second slope is calculated as the change amount ratio.

According to the material testing machine described in the fourth item, the change amount ratio can be calculated by the parameters related to the change of the first physical quantity and the second physical quantity in which the fluctuation of the measured value due to noise is removed. Therefore, since the fluctuation of the measured value due to noise is not taken into consideration in the calculation of the change amount ratio, the change amount ratio can be calculated accurately, and the feedback control of the load mechanism can be performed more accurately.

(Section 5)
The control method of the material testing machine according to another aspect measures a load mechanism for applying a load to the test object by a moving member and a first physical quantity generated in the test object or the load mechanism according to the application of the load. A first measuring unit, a second measuring unit that measures a second physical quantity that is a response in the feedback control of the load mechanism, and a first change amount that indicates a change in the first physical quantity measured by the first measuring unit. Adjust the time width of the measured values of the first physical quantity and the second physical quantity used for calculating the change amount ratio, which is the ratio of the second change amount indicating the change of the second physical quantity measured by the second measuring unit. Based on the time width adjusting unit, the change amount ratio calculation unit that calculates the change amount ratio in the time width adjusted by the time width adjusting unit, and the change amount ratio calculated by the change amount ratio calculation unit. A control method for a material testing machine including a control device having a feedback control unit that feedback-controls the load mechanism so as to reduce the deviation between the measured value of the second physical quantity and the target value of the second physical quantity. Therefore, the time width adjusting unit adjusts the time width so that it becomes longer as the noise included in the measured value of the second physical quantity increases, and the time change rate of the second physical quantity or the target speed of the moving member is adjusted. Perform at least one of the adjustments that make it shorter as it is larger.

According to the control method of the material testing machine according to the fifth item, the same effect as that of the material testing machine according to the first item is obtained.

1 Material testing machine 10 Crosshead (moving member)
12 Load mechanism 14 Load cell (2nd measuring unit)
18 Servo motor 20 Rotary encoder 30 Control device 60 Rotation amount measurement unit (1st measurement unit)
90 Elongator (2nd measuring unit)
541 Time width adjustment unit 542 Control compliance calculation unit 543 Feedback control unit 561 Target data F Test force (load)
RP response physical quantity (second physical quantity)
RPc target response physical quantity (target value of second physical quantity)
RPs measurement response physical quantity (measured value of the second physical quantity)
Slop1 1st slope Slop2 2nd slope Comp Control compliance (change ratio)
TP test piece (test target)
Tr rotation amount (first physical quantity)
e Deviation X Movement amount (first change amount)

Claims (5)

A load mechanism that applies a load to the test object by a moving member,
A first measuring unit that measures a first physical quantity generated in the test object or the load mechanism in response to the application of the load.
A second measuring unit that measures a second physical quantity that is a response in the feedback control of the load mechanism,
A change amount that is a ratio of a first change amount indicating a change in the first physical quantity measured by the first measuring unit and a second change amount indicating a change in the second physical quantity measured by the second measuring unit. A time width adjusting unit for adjusting the time width of the measured values of the first physical quantity and the second physical quantity used for calculating the ratio, and
A change amount ratio calculation unit that calculates the change amount ratio in the time width adjusted by the time width adjustment unit,
Feedback control that feedback-controls the load mechanism so as to reduce the deviation between the measured value of the second physical quantity and the target value of the second physical quantity based on the change amount ratio calculated by the change amount ratio calculation unit. With a department,
The time width adjusting unit
Either the adjustment that lengthens the time width as the noise contained in the measured value of the second physical quantity increases, or the adjustment that lengthens the time width as the time change rate of the second physical quantity or the target speed of the moving member increases. At least do
Material testing machine. The time width adjusting unit
The time width is adjusted so as to be equal to or less than the time width calculated based on the amplitude of noise included in the measured value of the second physical quantity when the moving speed of the moving member is the minimum speed.
The material testing machine according to claim 1. The time width adjusting unit
When the moving speed of the moving member is the maximum speed, the time width is adjusted so as to be equal to or greater than the shortest time width in which the change amount ratio can be calculated.
The material testing machine according to claim 1 or 2. The change ratio calculation unit
The first slope, which is the slope of an approximate straight line representing the relationship between the first physical quantity and time measured by the first measuring unit in the time width adjusted by the time width adjusting unit, is calculated.
The second slope, which is the slope of an approximate straight line representing the relationship between the second physical quantity and time measured by the second measuring unit in the time width adjusted by the time width adjusting unit, is calculated.
The ratio of the first slope to the second slope is calculated as the change amount ratio.
The material testing machine according to any one of claims 1 to 3. A load mechanism that applies a load to the test object by a moving member,
A first measuring unit that measures a first physical quantity generated in the test object or the load mechanism in response to the application of the load.
A second measuring unit that measures a second physical quantity that is a response in the feedback control of the load mechanism,
A change amount that is a ratio of a first change amount indicating a change in the first physical quantity measured by the first measuring unit and a second change amount indicating a change in the second physical quantity measured by the second measuring unit. A time width adjusting unit that adjusts the time width of the measured values of the first physical quantity and the second physical quantity used for calculating the ratio, and a change amount ratio that calculates the change amount ratio in the time width adjusted by the time width adjusting unit. The load mechanism is set so as to reduce the deviation between the measured value of the second physical quantity and the target value of the second physical quantity based on the calculation unit and the change amount ratio calculated by the change amount ratio calculation unit. A control method for a material testing machine including a control device having a feedback control unit for feedback control.
The time width adjusting unit
Either the adjustment that lengthens the time width as the noise contained in the measured value of the second physical quantity increases, or the adjustment that lengthens the time width as the rate of change in time of the second physical quantity or the target speed of the moving member increases. At least do
Control method of material tester.

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