JP2000131203A - Method of data sampling and control device having deta sampling function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control data points per one cycle of a change in controlled output to be constantly around an appropriate number, in the case that a target value signal is adapted to vary such that a value of the target value signal is started to increase when the controlled output decreases to a predetermined minimum value, while the value of the target value signal is started to decrease when the output increases to a predetermined maximum value, and that the output is sampled as data while feed-back controlling a controlled device. SOLUTION: In a low-cycle fatigue test, a hydraulic type material testing machine 12 is feed-back controlled while varying a target value signal Ds such that a value of a target value signal Ds is started to increase when a value of displacement, i.e., a controlled output decreases to a predetermined minimum value, while the value of the target value signal is started to increase if the value of displacement increases to an predetermined maximum value. A load, i.e., an output of the hydraulic type material testing machine 12, and the like are sampled as data whenever the value of displacement reach each of plural predetermined levels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data sampling method and a control device having a data sampling function, and more particularly, to feedback-control a device to be controlled while sampling the output amount of the device as data. And a control device having a data sampling function.

[0002]

2. Description of the Related Art When it is necessary to control a certain device with high precision, a feedback control method is often used. A typical configuration of a feedback control system includes a control target device, a sensor system that generates a sensor signal representing an output amount of the control target device, and a control signal for receiving the sensor signal from the sensor system and controlling the control target device. And a control device for generating Further, the control device generally includes a feedback unit that uses a sensor signal from a sensor system as a feedback signal to output an output amount represented by the sensor signal as a control target output amount, and a target unit that indicates a target value of the control target output amount. A target value signal generator for generating a value signal;
An error signal generator for generating a difference between the target value signal and the feedback signal as an error signal, and a control signal generator for generating a control signal according to the error signal are provided. The feedback control system having such a configuration is widely used in various fields.

In a usual feedback control system, the magnitude of a target value signal is set to be equal to the magnitude of a sensor signal (feedback signal) generated when the controlled object output amount reaches a target value. I have. If the target value signal is set in this manner, the feedback control system operates so that the difference (deviation) between the target value signal and the sensor signal (feedback signal) approaches “0”. Control is performed so as to approach the target value.

In a feedback control system having such a configuration, when the controlled device is a hydraulic material testing machine having a hydraulic actuator system, the response speed of the controlled device to a control signal is relatively low. The frequency response characteristic curve of the magnitude of the control target output amount (that is, the gain) with respect to the magnitude of the target value signal becomes a remarkably right-downward curve that rapidly decreases as the frequency increases.

[0005] When a fatigue test of a material is performed using a hydraulic material testing machine, the displacement of a load portion on which the test piece is mounted or the elongation of the test piece read from an extensometer directly mounted on the test piece is measured. The weight is repeatedly applied to the test piece by performing control so as to periodically change the amplitude at a desired amplitude. The frequency of the periodic change is often on the order of tens to hundreds of cycles / minute, but this is a considerably high frequency for a hydraulic material testing machine, and at such a frequency, the control target output is low. The actual amplitude of the displacement or elongation, which is the force, tends to be considerably smaller than the amplitude of the target value signal. Therefore, in order to perform the amplitude control of the output amount of the control target with high accuracy, some countermeasures are required.

Further, during the execution of the fatigue test, the transfer function of the hydraulic material testing machine may fluctuate mainly due to an increase in the temperature of the hydraulic oil of the hydraulic actuator system. When the control is performed at a low frequency, the influence of the change of the transfer function is not so large, but when the control is performed at a high frequency, the change is large in the amplitude of the displacement or elongation, which is the output amount to be controlled. Affect. Therefore, also from this point, some countermeasures are required to ensure the accuracy of the amplitude control.

[0007] One of the methods for controlling the amplitude of the output of the controlled object, which is periodically changed, with high accuracy is to determine the magnitude of the amplitude of the target value signal generated as a periodic function and the actual value of the amplitude as a result of the control. There is a method in which the magnitude of the amplitude of the output amount to be controlled is compared with a comparison unit provided separately from the error signal generation unit, and the target value signal is amplified with a compensation gain corresponding to the ratio between the amplitudes of the two. .

For example, there is a control system which is set so that the magnitude of a feedback signal representing the displacement is ± 5.0 V when the magnitude of the displacement which is the controlled object output amount is ± 1.0 mm. And In this control system, the amplitude of the target value signal is set to ± 5.0 V in order to perform control so as to periodically change the displacement with the amplitude being ± 1.0 mm. Then, when the control is actually performed by the target value signal set as described above, if the amplitude of the displacement actually generated becomes ± 0.8 mm for the above-described reason,
The target value signal is amplified with a compensation gain of “1.25” (= 1.0 / 0.8), and the amplitude of the target value signal is ±
If the voltage is set to 6.25 V, the amplitude of the displacement actually generated can be set to the desired amplitude of ± 1.0 mm.

In actual control, an operation for applying amplification corresponding to a compensation gain to a target value signal is performed by automatic control of the gain of a target value signal generator. May be called an AGC (Automatic Gain Control) method.

However, in the AGC system, when performing a control for periodically changing the controlled object output amount, during the execution of the control, based on the amplitude of the controlled object output amount actually generated in a certain cycle, Since the amplitude of the target value signal used in the next cycle is corrected, it is impossible to control the amplitude of the controlled output with high accuracy from the first cycle of the periodic control. is there. In addition, in order to perform stable control, it is desirable that the magnitude of the compensation gain be changed to some extent gently.
In such a case, the amplitude of the controlled object output amount cannot be controlled with high accuracy until the first few cycles of the periodic control have elapsed.

This means that the number of fracture cycles (that is, the number of repetitive loadings required to cause the specimen to fracture) is relatively large, and the area of the hysteresis curve of the stress-strain curve of the specimen is relatively small. There is no particular problem in the high cycle fatigue test, which is relatively small. However, in the low cycle fatigue test in which the number of fracture cycles is relatively small and the area of the hysteresis curve of the stress-strain curve of the test piece is relatively large, the amplitude of displacement or elongation, which is the controlled output, is controlled by the periodic control. The AGC method is inappropriate because it is necessary to control with high accuracy from the first cycle.

Here, the low cycle fatigue test will be briefly described. In a fatigue test of a metal material, by setting the magnitude of the cyclic load applied to the test piece to a relatively large value, the maximum plastic strain generated in the test piece (this corresponds to the residual strain in the stress-strain diagram) Do)
Can be made sufficiently large compared to the maximum elastic strain (which corresponds to the difference between the maximum total strain minus the maximum plastic strain). When a fatigue test is performed under such conditions, a so-called low-cycle fatigue fracture occurs in which the test piece is broken by a relatively small number of load application cycles of 10 ³ to 10 ⁴ times or less. This is called a fatigue test. In the low-cycle fatigue test, a large plastic strain is generated in the test piece, so that the stress-strain diagram of the test piece draws a large-area hysteresis loop.

On the other hand, the high cycle fatigue test is a fatigue test performed in such a manner that the maximum elastic strain generated in the test piece is sufficiently larger than the maximum plastic strain, contrary to the low cycle fatigue test. . When the fatigue test is performed under such conditions, the test piece is required to be 10 ³ to 1 until it breaks.
0 ⁴ times or more weighting applied cycle times are required, since the so-called high-cycle fatigue fracture occurs, which is referred to high cycle fatigue testing. In the high cycle fatigue test, only a small plastic strain is generated in the test piece, so the stress of the test piece
The hysteresis loop of the distortion diagram has a small area and an elongated shape.

In the low-cycle fatigue test, while a load is repeatedly applied to the test piece, the load actually applied to the test piece at that time and the displacement generated in the load-applying portion that applies the load to the test piece at that time. Alternatively, the elongation occurring in the test piece is measured, that is, sampling is performed as data. Then, the stress generated in the test piece is obtained from the measured load, and the strain generated in the test piece is obtained from the measured displacement or elongation. Further, a stress-strain diagram of the test piece is created based on the values of the stress and the strain, and various parameters relating to fatigue of the metal material are obtained by analyzing a hysteresis curve of the stress-strain diagram.

More specifically, data sampling is performed at a number of data points while the displacement or elongation of the test piece changes in one cycle.
This enables a stress-strain diagram to be created for each cycle of displacement or elongation. Then, from the hysteresis curve of the stress-strain diagram for each cycle,
Dynamic hardening index, Young's modulus, heat value per cycle or absorbed energy (which is equal to the loop area of the hysteresis curve), fatigue plasticity index, fatigue strength index, residual strain (ie, plastic strain), Elastic strain,
Then, the values of various parameters such as total strain are obtained, and the relationship between the values of those parameters and material fatigue is clarified.

The number of data points per cycle required to create a stress-strain diagram with sufficiently high accuracy that meets the purpose of such a low cycle fatigue test is usually several tens to Hundreds of thousands. In addition, in the low cycle fatigue test, in order to repeatedly apply a load to the test piece, control is performed to periodically change the displacement of the load applying portion for applying a load to the test piece or the elongation generated in the test piece. It is necessary to control the amplitude of the displacement or elongation with high precision from the first cycle of the periodic control.

In the above-mentioned AGC method, it is difficult to perform high-precision amplitude control required for a low-cycle fatigue test.
Another amplitude control method that can perform amplitude control with higher accuracy than the method is used. This amplitude control method starts increasing the value of the target value signal at a substantially constant speed when the value of the displacement or elongation, which is the output amount to be controlled, decreases to a predetermined minimum value, and when it increases to a predetermined maximum value. The target value signal generator is controlled so that the value of the target value signal begins to decrease at a substantially constant speed, whereby the value of the displacement or elongation, which is the output amount to be controlled, is changed from a predetermined minimum value to a predetermined maximum value. , And repeatedly changing from a predetermined maximum value to a predetermined minimum value. This method is sometimes called a level comparison method.

When this level comparison method is used, the target value signal is generated substantially in the form of a triangular wave signal. Further, when the direction of change of the target value signal is switched from increase to decrease or from decrease to increase, a slight amplitude error occurs due to the overshoot of the output of the controlled object, but this amplitude error is very small. By using the level comparison method, it is possible to control the amplitude of the control target output amount with very high accuracy from the first cycle of the periodic control.

However, this level comparison method has a disadvantage that the period of the target value signal generated in the form of a triangular wave signal cannot be set accurately. In the above-described AGC method, the cycle of the target value signal can be specified irrespective of the current value of the output amount of the control target, so that the desired value can be accurately set. When the current value of the output amount reaches the maximum value or the minimum value, the direction of change of the target value signal is switched. Will be affected. for that reason,
The cycle of the target value signal may be significantly different from the expected cycle.Furthermore, as the temperature of the hydraulic oil of the hydraulic actuator system and the characteristics of the test piece change during the execution of the low cycle fatigue test, the The period of the value signal may fluctuate.

[0020]

Conventionally, data sampling in a low cycle fatigue test is performed at predetermined time intervals (for example, at a sampling period of several hundreds to several thousands of microseconds).
This was done by sampling. However, as described above, when the level comparison method is used to control the amplitude of displacement or elongation with high accuracy, the cycle period, which is the time during which the displacement or elongation changes by one cycle, is accurately determined. Since it cannot be set, it is necessary to set a shorter sampling period in advance so that a sufficient number of data points can be secured even if the cycle period is eventually shortened. If the actual cycle period is relatively long, the number of data points per cycle becomes unnecessarily large.

For example, when an estimate was made in formulating a test plan for a certain low cycle fatigue test, in order to obtain a test result having sufficient accuracy, the number of data points for drawing one hysteresis curve was several hundred. (Ie, data must be collected at hundreds of data points per cycle), and the maximum number of break cycles is expected to be 100,000 cycles And In this case, if you want to record all the changes in the state of the specimen up to the fracture,
At most, it is necessary to sample and store several hundreds of data = tens of millions of data.

In addition, although the data sampling cycle is previously set short so as to cope with the case where the cycle cycle is relatively short as a result, the actual cycle cycle becomes relatively long. In addition, if the number of break cycles is considerably large, it is necessary to sample several times more data.

Conventionally, when a low cycle fatigue test is performed using the level comparison method, an enormous data storage capacity is required if the cycle period of displacement or elongation, which is the control target, becomes long. In addition, there has been a problem that the amount of data processing related to the analysis of the hysteresis curve also increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. One object of the present invention is to perform feedback control of a device to be controlled while sampling the output amount of the device to be controlled as data. In the data sampling method for, the value of the target value signal begins to increase when the value of the control target output amount decreases to a predetermined minimum value,
When performing control to change the target value signal so that the value of the target value signal starts to decrease when the value of the control target output amount increases to a predetermined maximum value, one of the changes in the control target output amount
An object of the present invention is to provide a data sampling method capable of ensuring that the number of data points per cycle does not become too small or too large, and is always close to an appropriate number.

Another object of the present invention is to provide a control device having a data sampling function for sampling the output amount of the controlled device as data while performing feedback control on the controlled device. The target is set to start increasing the value of the target value signal when the value of the output amount decreases to the predetermined minimum value, and to start decreasing the value of the target value signal when the value of the controlled object output amount increases to the predetermined maximum value. When performing control to change the value signal,
Provided is a control device having a data sampling function that can keep the number of data points per one cycle of a change in the controlled object output amount to be not too small or too large and always be close to an appropriate number. Is to do.

[0026]

According to a first aspect of the present invention, there is provided a data sampling method according to the present invention, wherein a plurality of sensor signals representing a plurality of output amounts of a controlled object device are provided. A plurality of sensor systems, each of which generates, and a feedback unit that uses one sensor signal of the plurality of sensor signals as a feedback signal to make an output amount represented by the sensor signal a control target output amount,
A target value signal generation unit that generates a target value signal representing a target value of the control target output amount, an error signal generation unit that generates a difference between the target value signal and the feedback signal as an error signal, Using a feedback control system including a control signal generation unit that generates a corresponding control signal, when the value of the control target output amount decreases to a predetermined minimum value, the value of the target value signal starts increasing, By controlling the target value signal generator so that the value of the target value signal starts decreasing when the value of the control target output amount increases to a predetermined maximum value, the control target output amount is reduced to the predetermined minimum value. To the predetermined maximum value and from the predetermined maximum value to the predetermined minimum value while repeatedly changing one or more of the plurality of output amounts of the plurality of output amounts of the controlled object device. A data sampling method for sampling a data, is characterized by performing data sampling every time the value of the control target output quantity reaches each of a plurality of predetermined levels.

The data sampling method according to the present invention is characterized in that the plurality of predetermined levels are set at equal level intervals.

In the data sampling method according to the present invention, the plurality of predetermined levels are set at unequal level intervals.

According to a fourth aspect of the present invention, in the data sampling method according to the present invention, in a range between the predetermined maximum value and the predetermined minimum value in the range of the controlled output amount, a first level interval is provided. The plurality of predetermined levels are set at equal level intervals, and in a value range of the output amount of the control target, in a region deviating from a region between the predetermined maximum value and the predetermined minimum value, the value is smaller than the first level interval. The plurality of predetermined levels are set at equal level intervals with a second level interval.

According to a fifth aspect of the present invention, in the data sampling method according to the present invention, in a range between the predetermined maximum value and the predetermined minimum value in the value range of the control target output amount, the data sampling method has the same level interval. A plurality of predetermined levels are set, and in a range of the output amount of the control target, in a region outside a region between the predetermined maximum value and the predetermined minimum value, data sampling is performed at predetermined time intervals. I have.

According to a sixth aspect of the present invention, in the data sampling method of the present invention, the controlled object device is a hydraulic material testing machine having a hydraulic actuator system, and the control of the target value signal generating section is performed by: Executed as a control for a low cycle fatigue test of a test piece mounted on the hydraulic material testing machine, an output amount related to a load applied to the test piece and an output amount related to a deformation amount generated in the test piece. Is sampled as data.

According to a seventh aspect of the present invention, there is provided a data sampling method according to the present invention, wherein the first output amount of a control target device which generates a plurality of output amounts including a first output amount and a second output amount is feedback controlled. And a data sampling method for sampling at least the second output amount of the plurality of output amounts as data, wherein data sampling is performed each time the value of the first output amount reaches each of a plurality of predetermined levels. It is characterized by performing.

According to another aspect of the present invention, there is provided a control device having a data sampling function according to the present invention, wherein a plurality of sensor signals respectively representing a plurality of sensor signals representing a plurality of output amounts of the controlled object device are provided. Used in combination with a sensor system,
A control unit having a data sampling function, wherein one of the plurality of sensor signals is used as a feedback signal so that an output amount represented by the sensor signal is used as a control target output amount; A target value signal generator that generates a target value signal representing a target value of the output amount; an error signal generator that generates a difference between the target value signal and the feedback signal as an error signal; and control according to the error signal. A control signal generating unit that generates a signal, and starts increasing the value of the target value signal when the value of the controlled object output amount decreases to a predetermined minimum value, and increases the value of the controlled object output amount to a predetermined maximum value By controlling the target value signal generation unit so as to start decreasing the value of the target value signal when the control target output amount has reached the predetermined minimum value. A target value signal generator control means for repetitively changing from the predetermined maximum value to the predetermined maximum value and from the predetermined maximum value to the predetermined minimum value, and one of the plurality of output amounts of the controlled device. Data sampling means for sampling one or more output amounts as data, wherein the data sampling means determines whether or not the value of the controlled output amount has reached each of a plurality of predetermined levels. Equipped with arrival determination means,
Each time the level reaching determination means determines that the value of the controlled object output amount has reached each of the plurality of predetermined levels,
It is characterized in that it is configured to perform data sampling of the output amount of the control target device.

[0034] A control device having a data sampling function according to the present invention is characterized in that the plurality of predetermined levels are set at equal level intervals.

In the control device having a data sampling function according to the present invention, the plurality of predetermined levels are set at unequal level intervals.

Further, in the control device having the data sampling function of the present invention according to the present invention, in the range of the controlled object output amount between the predetermined maximum value and the predetermined minimum value, The plurality of predetermined levels are set at equal level intervals with a first level interval, and in a value range of the control target output amount, in a region outside a region between the predetermined maximum value and the predetermined minimum value, The plurality of predetermined levels are set at equal level intervals with a second level interval smaller than the first level interval.

According to a twelfth aspect of the present invention, in the control device having the data sampling function according to the present invention, in the range of the controlled object output amount, the range between the predetermined maximum value and the predetermined minimum value includes: The plurality of predetermined levels are set at equal level intervals, and the data sampling means further determines whether a current value of the controlled object output amount is in an area between the predetermined maximum value and the predetermined minimum value. Control target output amount current value region determining means for determining the value of the control target output amount, in a range outside the region between the predetermined maximum value and the predetermined minimum value, a predetermined time interval Is characterized by performing data sampling.

According to a thirteenth aspect of the present invention, in the control device having a data sampling function according to the present invention, the controlled object device is a hydraulic material testing machine having a hydraulic actuator system, and the target value signal generator Is executed as a control for a low-cycle fatigue test of a test piece mounted on the hydraulic material testing machine, and the output amount of the controlled device, which is sampled as data, is a load applied to the test piece. And an output amount related to an amount of deformation generated in the test piece.

According to a fourteenth aspect of the present invention, there is provided a control device having a data sampling function according to the present invention, wherein the first controlled object device generates a plurality of output quantities including a first output quantity and a second output quantity. In a control device having a data sampling function, wherein at least the second output amount of the plurality of output amounts is sampled as data while performing feedback control of the output amount, the value of the first output amount may be a plurality of predetermined levels. Level determination means for determining whether or not each of the plurality of predetermined levels has been reached, and each time the level arrival determination means determines that the value of the first output amount has reached each of the plurality of predetermined levels, Is characterized in that at least the second output amount among the output amounts is sampled.

According to the data sampling method of the present invention, the control target output amount that repeatedly changes from the maximum value to the minimum value and from the minimum value to the maximum value reaches a predetermined level. To perform data sampling,
The number of data points per cycle of the repetitive change of the controlled object output amount is not affected by the length of the cycle of the repetitive change. Therefore, the number of data points does not become too small or too large. It is possible to make the number close to the appropriate number.

In the data sampling method according to the present invention, a plurality of predetermined levels are set at equal level intervals, which is a method that can be suitably applied to many uses. In addition, in this way, in addition to storing the set level in the look-up table, it becomes easy to calculate a predetermined level for the next data sampling by calculation.

According to the data sampling method of the present invention, since a plurality of predetermined levels are set at unequal level intervals, an important portion of the range of the output amount of the control target is small. By setting the level interval, it is possible to increase the resolution of the data in that part.

According to the data sampling method of the present invention, in the range of the controlled object output amount, the region between the predetermined maximum value and the predetermined minimum value has the first level interval. A plurality of predetermined levels are set at a level interval, and in an area deviating from an area between a predetermined maximum value and the predetermined minimum value, a plurality of predetermined levels are set at equal level intervals at a second level interval smaller than the first level interval. When applying this data sampling method to a low cycle fatigue test using a material testing machine, the accuracy of the important part of the hysteresis curve of the stress-strain diagram created based on the sampled data should be improved. Is possible.

According to the data sampling method of the present invention, in a range between the predetermined maximum value and the predetermined minimum value in the value range of the controlled object output amount, a plurality of values are provided at equal level intervals. A predetermined level is set, and data sampling is performed at predetermined time intervals in an area deviating from an area between the predetermined maximum value and the predetermined minimum value. When the method is applied to a low-cycle fatigue test using a material testing machine, it is possible to increase the accuracy of an important part of a hysteresis curve of a stress-strain diagram created based on sampled data.

Further, in the data sampling method according to the present invention, the controlled object device is a hydraulic material testing machine having a hydraulic actuator system, and the control of the target value signal generating unit is controlled by the hydraulic type material testing machine. It is executed as a control for low cycle fatigue test of the test piece mounted on the material testing machine, and the output amount related to the load applied to the test piece and the output amount related to the deformation amount generated in the test piece as data Sampling, which is defined in claims 1 to 5
2 shows a preferable application object in which a particularly great advantage can be obtained by applying the data sampling method described in (1).

Further, according to the data sampling method of the present invention, the first output amount of the controlled device that generates a plurality of output amounts including the first output amount and the second output amount is feedback-controlled. A data sampling method for sampling at least a second output amount of the plurality of output amounts as data, wherein data sampling is performed each time the value of the first output amount reaches each of a plurality of predetermined levels. This clearly shows the excellent features of the data sampling method according to the present invention.

According to the control device having the data sampling function of the present invention, the controlled object output amount which repeatedly changes from the maximum value to the minimum value and from the minimum value to the maximum value is determined by the predetermined value. Since data sampling is performed each time the level is reached, the number of data points per cycle of the repetitive change of the controlled output amount is not affected by the length of the cycle of the repetitive change. It is possible that the number is not too small or too large, and is always close to an appropriate number.

According to a ninth aspect of the present invention, there is provided a control device having a data sampling function according to the present invention, wherein a plurality of predetermined levels are set at equal level intervals.
This is a device that can be suitably applied to many uses. In such a device, besides storing the set level in a lookup table, a predetermined level for the next data sampling is calculated. It is also easy to calculate.

According to the control device having the data sampling function of the present invention, a plurality of predetermined levels are set at unequal level intervals. By setting a small level interval for an important part, it is possible to increase the resolution of the data of that part.

Further, according to the control device having the data sampling function of the present invention described in claim 11, in the range between the predetermined maximum value and the predetermined minimum value in the range of the controlled object output amount, A plurality of predetermined levels are set at equal level intervals at one level interval. In an area deviating from an area between a predetermined maximum value and the predetermined minimum value, equal levels are set at a second level interval smaller than the first level interval. Since a plurality of predetermined levels are set at intervals, when a control device having this data sampling function is applied to a low-cycle fatigue test using a material testing machine, a stress generated based on the sampled data is used. It is possible to improve the accuracy of the important part of the hysteresis curve of the strain diagram.

Further, according to the control device having the data sampling function of the present invention, in the range of the output amount of the controlled object, the range between the predetermined maximum value and the predetermined minimum value is equal. The data sampling according to claim 11, wherein a plurality of predetermined levels are set at level intervals, and data sampling is performed at predetermined time intervals in a region outside a region between a predetermined maximum value and a predetermined minimum value. Similarly to a control device having a function, when a control device having this data sampling function is applied to a low cycle fatigue test using a material testing machine, a stress-strain diagram created based on the sampled data. Of the important part of the hysteresis curve can be improved.

According to a thirteenth aspect of the present invention, there is provided a control device having a data sampling function according to the present invention, wherein the control target device is a hydraulic material testing machine having a hydraulic actuator system, and the control of the target value signal generation unit is performed. Is executed as a control for the low cycle fatigue test of the test piece mounted on the hydraulic material testing machine, and the output amount of the control target device sampled as data is the output amount related to the load applied to the test piece. And an output amount related to an amount of deformation generated in the test piece.
In particular, the present invention shows a suitable application object in which a particularly great advantage is obtained by applying the control device having the data sampling function described in (1).

According to a fourteenth aspect of the present invention, there is provided a control device having a data sampling function according to the first aspect of the present invention, wherein a control target device for generating a plurality of output quantities including a first output quantity and a second output quantity. In a control device having a data sampling function, which samples at least a second output amount of the plurality of output amounts as data while performing feedback control of the power amount, the value of the first output amount is set to each of a plurality of predetermined levels. Each time the level attainment determination means determines that the data has been reached, data sampling of at least the second output amount of the plurality of output amounts is performed. This is a control device having a data sampling function according to the present invention. This is a simple illustration of the excellent features of

[0054]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the feedback control system 10. This feedback control system 10 includes a control device having a data sampling function according to a preferred embodiment of the present invention, and implements a data sampling method according to a preferred embodiment of the present invention. It is a control system suitable for

The feedback control system 10 shown in FIG.
Is a hydraulic material testing machine 12 which is a device to be controlled, and a load sensor system 14a and a displacement sensor system 14a which respectively detect a load and a displacement which are output amounts of the hydraulic material testing machine 12.
b, and a digital signal processor 16 which receives the sensor signals generated by the sensor systems 14a and 14b and outputs a control signal for controlling the material testing machine 12.

The material testing machine 12, the sensor system 14a,
14b and the digital signal processing device 16 are both under the control of the host computer 18, as schematically shown by the connection symbol C in FIG. The operator of the material testing machine 12 can set various parameters of the material testing machine 12, the sensor systems 14a and 14b, and the digital signal processing device 16 by operating the host computer 18.

As will be described in detail below, the digital signal processing device 16 and the host computer 18 constitute a control device having a data sampling function according to a preferred embodiment of the present invention. .

The material testing machine 12 is supported by a testing machine frame, a hydraulic actuator system, a fixed-side load applying portion whose fixing position is fixed to the testing machine frame in an adjustable manner, and movably supported by the testing machine frame. A movable-side load applying unit driven by a hydraulic actuator system. And
A test piece is mounted directly or via a fixture such as a chuck between the fixed and movable load portions, and various test operations are performed on the test piece by operating the hydraulic actuator system. It is configured so that it can be added.

However, in the present invention, the material testing machine 12
1 is shown in FIG. 1 as a single block, since the specific detailed configuration is not important. When the material testing machine 12 is controlled by the digital signal processor 16, it means that the digital signal processor 16
Means that the hydraulic actuator system of the material testing machine 12 is controlled.

When the hydraulic actuator system of the material testing machine 12 operates, the physical quantity related to the test piece mounted on the material testing machine 12 changes. In the illustrated example, one of the physical quantities related to the test piece is a load applied to the test piece, and the other is a deformation (strain) generated in the test piece.

It is needless to say that the load sensor system 14a detects the load applied to the test piece. On the other hand, the amount of deformation generated in the test piece is proportional to the magnitude of the displacement of the movable load portion of the material testing machine 12, so the displacement sensor system 14b
Is detected by

The load sensor system 14a can be composed of, for example, a load cell attached to one load load section of the material testing machine 12, a bridge circuit associated with the load cell, and a sensor amplifier connected to the bridge circuit. it can. Further, the displacement sensor system 14b can be composed of, for example, a potentiometer attached between the tester frame of the material testing machine 12 and the movable load portion, and a sensor amplifier connected to the potentiometer. In such a configuration, the output ranges of the sensor systems 14a and 14b can be adjusted by appropriately setting the amplification factors of the sensor amplifiers via the host computer 18. Is good.

The configurations of the sensor systems 14a and 14b are not limited to those described above, and an appropriate one of various specific configurations of known sensor systems may be used. In the illustrated example, the sensor signals generated by the sensor systems 14a and 14b and representing the detected output amounts of the load and the displacement, respectively, are both analog sensor signals.

The digital signal processing device 16 includes a CPU,
It has a general configuration in which a RAM, a ROM, and a multiply-accumulate unit are combined. For the present invention, the function is more important than the specific configuration. The function of the device 16 is shown in the form of a block diagram combining several functional elements. It is obvious for a person skilled in the art how to configure hardware and how to create a program in order to realize the functions of each of these functional elements. Omitted.

The digital signal processor 16 has an A / D converter 22a for converting analog sensor signals received from the sensor systems 14a and 14b into digital signals.
And 22b. Those A / D converters 22
Each output of a and 22b is connected to the host computer 18 as schematically shown by a connection symbol D in FIG. The host computer 18 can sample the output amount of the material testing machine 12 as data by sampling the outputs (ie, sensor signals) of the A / D converters 22a and 22b, and the sampled data is Are stored in the memory of the host computer 18.

The digital signal processing device 16 further includes A /
It has a selector 24 to which the outputs of the D converters 22a and 22b are connected. The selector 24 receives the A / D signals according to a command signal received from the host computer 18.
Only one of the outputs (ie, sensor signals) of the converters 22a and 22b is selected and passed. The sensor signal Ss that has passed through the selector 24 is used as a feedback signal Ss in the feedback control system 10. Therefore, the output amount corresponding to the sensor signal selected by the selector 24 is equal to the output amount to be controlled by the feedback control system 10. Become. Therefore, the selector 24 constitutes a feedback unit that uses one sensor signal of the plurality of sensor signals as a feedback signal and uses the output amount represented by the sensor signal as the control target output amount.

The digital signal processor 16 further generates a target value signal generator 26 for generating a target value signal Ds representing the target value of the output quantity to be controlled, and calculates the difference between the target value signal and the feedback signal Ss as an error signal Es Signal generation section 28 generated as a control signal Cs corresponding to error signal Es
And a control signal generator 32 for generating

The target value signal Ds generated by the target value signal generator 26 is a digital signal representing the target value of the controlled output amount as a function of time. The target value signal generator 26 is controlled by the host computer 18 as schematically shown by a connection symbol C in FIG. The target value signal Ds includes control data to be loaded into the digital signal processor 16 by the host computer 18 prior to execution of the material test, and the host computer 1 during execution of the material test.
8 may be generated as a ramp function for a tensile strength test, a sinusoidal function for a fatigue strength test, and It may also be generated as any other suitable function for mounting and removing pieces.

The error signal generator 28 calculates the difference between the value of the digital feedback signal Ss output from the selector 24 and the value of the digital target value signal Ds output from the target value signal generator 26, and calculates the difference. It is output as a digital error signal Es. Error signal generator 28
Performs necessary operations on the CPU of the digital signal processor 16.
, It is possible to realize only by software, and it is also possible to configure it by using appropriate hardware together.

The control signal generator 32 performs an arithmetic operation on the digital error signal Es to generate a digital control signal Cs. This arithmetic processing is performed by the host computer 18 prior to the execution of the material test.
Are executed as various types of arithmetic operations in accordance with control data to be loaded into the digital signal processor 16 and commands issued by the host computer 18 to the digital signal processor 16 during execution of the material test. Specifically, for example, it may be executed as a simple operation of multiplying a digital error signal by a specified constant, or may be performed by multiplying the digital error signal by a constant, an integral value, a differential value, and a digital error signal. It may be executed as an operation to calculate the sum of the calculated values and the appropriate combination.

As will be easily understood, the control characteristics of the feedback control system 10 can be variously set by appropriately determining the form of the operation executed by the control signal generator 32. For example, when the transfer function of the control target mechanism can be approximated by a constant, and thus the control target mechanism can be considered to be substantially a proportional element, the operation performed by the control signal generating unit 32 includes a digital error signal Es , The control characteristic of the feedback control system 10 performs proportional control (P operation). If the calculation is a calculation of a sum of a value obtained by multiplying the digital error signal Es by a constant, an integral value of the digital error signal Es, and a differential value of the digital error signal Es, the control of the feedback control system 10 is performed. The characteristics are those for performing proportional / integral / differential control (PID operation).

As described above, the control signal Cs generated by the control signal generator 32 is a digital signal. The digital signal processing device 16 includes a D / A converter 34 for converting the control signal Cs from a digital signal to an analog signal. This is provided because the material testing machine 12 is configured to be controlled by analog control signals. Therefore, when the device to be controlled is configured to be controlled by the digital control signal, the D / A converter 34 is unnecessary.

As is well known, in the ordinary feedback control system, the magnitude of the target value signal Ds is set to be equal to the magnitude of the sensor signal (feedback signal) Ss generated when the output of the controlled object reaches the target value. I am trying to do it. If the target value signal Ds is set in this manner, the feedback control system 10 sets the difference (deviation) between the target value signal Ds and the sensor signal (feedback signal) Ss to “0”.
, The control target output amount is controlled so as to approach the target value.

However, since the hydraulic material testing machine 12 has a hydraulic actuator system having a relatively slow operating speed, the response speed of the hydraulic material testing machine 12 to the control signal Cs is relatively low. Therefore, the frequency response characteristic curve of the magnitude of the displacement (that is, the gain), which is the output amount of the control target with respect to the magnitude of the target value signal Ds, becomes a remarkably right-downward curve that rapidly decreases as the frequency increases.

When a fatigue test of a material is performed using the hydraulic material testing machine 12, control is performed so that the displacement of the load portion on which the test piece is mounted is periodically changed at a desired amplitude. By doing so, a load is repeatedly applied to the test piece. The frequency of the periodic change is often on the order of tens to hundreds of cycles / minute, but this is a rather high frequency for the hydraulic material testing machine 12 and at such frequencies the control The actual amplitude of the displacement of the load portion, which is the target output amount, tends to be considerably smaller than the amplitude of the target value signal.

Further, during the execution of the fatigue test, the transfer function of the hydraulic material testing machine 12 may fluctuate mainly due to an increase in the temperature of the hydraulic oil of the hydraulic actuator system.
When the control is performed at a low frequency, the influence of the fluctuation of the transfer function is not so large. However, when the control is performed at a high frequency, it greatly affects the amplitude of the displacement, which is the output amount to be controlled.

In view of these circumstances, generally, when the above-described ordinary feedback control method is used, when the displacement of the load load portion of the hydraulic material testing machine is periodically changed at a relatively high frequency, It is difficult to control the amplitude of the displacement with high accuracy.

Therefore, when it is necessary to control the amplitude of displacement with high accuracy, the AGC method and the level comparison method described in detail in the description of the conventional technique are used. In particular, when performing a low cycle fatigue test, a level comparison method capable of controlling the amplitude with higher accuracy is used. In this level comparison method, the value of the displacement, which is the output amount to be controlled, is a predetermined minimum value. So that the value of the target value signal Ds starts increasing at a substantially constant speed when it has decreased to a predetermined maximum value, and starts decreasing at a substantially constant speed when it has increased to a predetermined maximum value. The control of the target value signal generator 26 is performed, whereby the displacement as the controlled object output amount is repeatedly changed from the predetermined minimum value to the predetermined maximum value and from the predetermined maximum value to the predetermined minimum value. .

According to this level comparison method, the target value signal is generated substantially in the form of a triangular wave signal. When the change direction of the target value signal Ds is switched from increase to decrease or from decrease to increase, the displacement which is the controlled object output amount causes an overshoot. Therefore, a slight error occurs in the amplitude of the displacement, but the amplitude error is very small.

In order to control the operation of the target value signal generator 26 as described above, the digital signal processor 16 includes a triangular wave signal generation controller 40. The triangular-wave signal generation control unit 40 receives the feedback signal Ss from the selector 24, and controls the target value signal generation unit 26 based on the feedback signal Ss in the above-described manner, thereby controlling the amplitude in the above-described level comparison system. Is realized.

Therefore, the triangular wave signal generation control section 40 starts increasing the value of the target value signal Ds at a substantially constant speed when the value of the displacement, which is the output amount to be controlled, decreases to a predetermined minimum value. By controlling the target value signal generator 26 so as to start decreasing the value of the target value signal Ds at a substantially constant speed when increasing to a predetermined maximum value, the displacement, which is the controlled object output amount, is reduced to a predetermined minimum value. From a predetermined maximum value to a predetermined maximum value and from a predetermined maximum value to a predetermined minimum value.

The triangular wave signal generation control section 40 can be constituted by wiring logic, and can be realized by software by causing the CPU of the digital signal processing device 16 to execute necessary operations. FIG. 2 is a block diagram showing one specific example in the case where this is constituted by wiring logic. The triangular-wave signal generation control unit 40 in FIG. 2 controls the displacement so that the magnitude of the displacement represented by the sensor signal generated by the displacement sensor system 14b repeatedly changes between the maximum value Rmax and the minimum value Rmin. It controls the amplitude.
Note that these two values can be arbitrarily set by the operator so that Rmax> Rmin within the operation range of the material testing machine 12. However, here, for simplicity of explanation, Rmax is used. = −Rmin.

The triangular wave signal generation control section 40 shown in FIG.
A comparator 42a and a second comparator 42b are provided, and a feedback signal (sensor signal) Ss is input to a first input of each of the comparators 42a and 42b. The feedback signal S when the displacement is Rmax is supplied from the first reference value generation source 44a to the second input of the first comparator 42a.
A reference value equal to the value of s (also represented by Rmax) has been entered. The second input of the second comparator 42b is supplied from the second reference value source 44b to a reference value (also Rmi) equal to the value of the feedback signal Ss when the displacement is Rmin.
n) is input.

The output of the first comparator 42a is output when the value of the feedback signal Ss is larger than the reference value Rmax (Ss
> Rmax) is “1”, otherwise it is “0”. The output of the second comparator 42b is output when the value of the feedback signal Ss is smaller than the reference value Rmin (S
s <Rmin) is “1”, otherwise it is “0”. The output of the first comparator 42a is input to the first input of the first AND gate 46a, and the second comparator 42a
The output of b is input to a first input of a second AND gate 46b.

A status signal can be taken out from the target value signal generator 26. This status signal is output to the target value signal generator 2 in the level comparison mode.
6 is "1" when transmitting an output that increases at a substantially constant rising speed (INC), and is transmitting an output that decreases at a substantially constant decreasing speed (DEC). Is "0". This status signal is the first A
The second input of the ND gate 46a is input as it is, and the second input of the second AND gate 46b is connected to the inverter 48.
Input after being inverted.

The triangular wave signal generation control section 40 further has a flip-flop 50. First AND gate 46a
Is input to the "0" input of the flip-flop 50, and the output of the second AND gate 46b is input to the "1" input of the flip-flop 50. The output of the flip-flop 50 becomes “1” when the combination of the “1” input and the “0” input becomes (1, 0), and becomes “0” when it becomes (0, 1). become. When the combination of inputs is (0,0), the output of flip-flop 50 does not change. Further, in the configuration of FIG. 2, the combination of inputs does not become (1, 1).

The output of the flip-flop 50 is sent as a command signal from the triangular wave signal generation control section 40 and is input to the target value signal generation section 26. When the command signal becomes "1" while the target value signal generator 26 is in the level comparison mode, the output of the target value signal generator 26 increases from the output value at that time at a substantially constant rising speed. Get started. When the command signal becomes "0", the output of the target value signal generator 26 starts to decrease at a substantially constant rate from the output value at that time.

With the above configuration, as described above,
It is possible to periodically change the displacement, which is the output amount to be controlled, and to control the amplitude of the displacement to the target amplitude (ie, Rmax−Rmin) with high accuracy.

FIG. 3 is a flowchart showing a specific example of a case where the triangular wave signal generation control section 40 is realized by software by causing the CPU of the digital signal processing device 16 to execute necessary operations. Each of the steps is a step executed by the CPU of the digital signal processing device 16.

In FIG. 3, first, the value of the feedback signal Ss is read (S102), and the read value is compared with the value of Rmax described above (S104). If Ss> Rmax, the target value signal generator 26
The value of the I / D flag indicating whether the output value of the target value signal should be increased or decreased is set to “0” to indicate that the output value of the target value signal generator 26 should be reduced ( S106).

On the other hand, if Ss> Rmax is not satisfied,
Subsequently, the read value is compared with the value of Rmin described above (S108). If Ss <Rmin, the value of the I / D flag is set to “1” to indicate that the output value of the target value signal generator 26 should be increased (S
110). Then, the above steps S102 to S110 are repeatedly executed until it is indicated in step S112 that the level comparison mode should be ended.

As described above, when the triangular wave signal generation control unit 40 is realized by software and the I / D flag is used, the I / D flag is used from the target value signal generation unit 26 side.
Refer to the D flag. In such a case, the configuration of the target value signal generator 26 for operating in the mode of the level comparison method may be, for example, a configuration as shown in the flowchart of FIG. 4, and each step in FIG. Are the steps executed by the CPU of the digital signal processing device 16.

In the flowchart of FIG. 4, first, a standby time ΔT corresponding to the increase / decrease speed of the target value signal Ds output from the target value signal generator 26 is calculated (S122).
The value of the waiting time ΔT has a small value when the increase / decrease speed is high, and has a large value when the increase / decrease speed is low. Subsequently, after waiting for this ΔT (S124), the I / D flag is referenced (S126, S130). And the I /
If the D flag is “1”, the target value signal generator 2
In step S128, the value of the target value signal Ds output from No. 6 is incremented by a predetermined increment ΔS (S128). If the I / D flag is “0”, the value of the target value signal Ds is changed by ΔS
Is decremented by one (S132). The above steps S124 are performed until it is indicated in step S134 that the operation in the mode of the level comparison method should be ended.
To S132 are repeatedly executed.

FIG. 5A employs the level comparison method in which the amplitude of the displacement, which is the control target output amount, is controlled by controlling the target value signal generation unit 26 by the triangular wave signal generation control unit 40 as described above. FIG. 5B is a waveform diagram showing the result when the above-described normal feedback control method is adopted for comparison with the result.

When the ordinary feedback control method is employed, as shown in FIG.
The value of the target value signal Ds at which a triangular wave signal having a value corresponding to the target upper limit value Rmax of the control target output amount as an upper limit and a lower limit value corresponding to the target lower limit value Rmin of the control target output amount as the lower limit is generated. Is set to

In this case, the controlled object output amount represented by the sensor signal (feedback signal) Ss is equal to the target value signal Ds
At the time when the direction of change of the target value signal Ds reverses from increase to decrease or from decrease to increase, the target upper limit value Rmax or the target lower limit value Rmin
And the change direction of the target value signal Ds is reversed, and at the same time, the increasing speed or the decreasing speed of the controlled object output amount is rapidly changing. Therefore, the actual amplitude of the control target output amount is considerably smaller than the target amplitude (Rmax−Rmin).

The difference between the target amplitude and the actual amplitude can be compensated for by using the AGC method described in detail in the description of the prior art at the beginning of the present specification. As described above, since the amplitude cannot be controlled with high precision from the first cycle of the periodic control, it is not suitable for a low cycle fatigue test.

On the other hand, when the above-described level comparison method is used, as shown in FIG. 5A, the output of the control target represented by the sensor signal (feedback signal) Ss is actually the target upper limit value. Since the change direction of the target value signal Ds is reversed at the time of reaching Rmax or the target lower limit value Rmin, the amplitude of the controlled object output amount becomes equal to the target amplitude (Rmax-R
min).

More specifically, the output amount of the control target slightly exceeds the target limit values Rmax and Rmin because an overshoot occurs when the change direction of the target value signal Ds is reversed. However, the protruding amount is exaggerated in FIG. 5A for easy understanding, but is actually very small, and therefore, high-precision amplitude control is possible.

When the ordinary feedback control method is employed or when the AGC method is employed, the cycle of the target value signal Ds transmitted as a triangular wave signal is set to the exact cycle T0 as specified in advance. However, the period Ta generated in the amplitude control using the level comparison method has a different length depending on the characteristics of the test piece mounted on the material testing machine 12, and further, the hydraulic oil of the hydraulic actuator system of the material testing machine 12 May also change due to changes in the temperature or the like.

Since the conventional data sampling method in the low cycle fatigue test is to perform data sampling at a predetermined cycle, when the cycle cycle of the target value signal Ds in the form of a triangular wave signal changes, the cycle per one cycle is changed. The number of times of data sampling has changed, thereby causing the inconvenience as described in the description of the problem to be solved by the invention.

The present invention solves the above-mentioned inconvenience by performing data sampling each time the value of the controlled object output amount reaches each of a plurality of predetermined levels. Hereinafter, some embodiments of the data sampling method of the present invention will be described with reference to a feedback control system 10 shown in FIG.
A description will be given of the case where a low cycle fatigue test is performed using

Here, in order to facilitate understanding of the present invention, a low cycle fatigue test will be outlined here. As described above, the low-cycle fatigue test is a test of the maximum plastic strain generated in a specimen by setting the magnitude of the cyclic load applied to the specimen to a relatively large value in a fatigue test of a metal material. Is equivalent to the residual strain in the stress-strain diagram), but is sufficiently large compared to the maximum elastic strain (this is the difference between the maximum total strain minus the maximum plastic strain). is there. When a fatigue test is performed under such conditions, a so-called low-cycle fatigue fracture occurs in which the test piece is broken by a relatively small number of load application cycles of 10 ³ to 10 ⁴ times or less. In the low-cycle fatigue test, a large plastic strain is generated in the test piece, so that the stress-strain diagram of the test piece draws a large-area hysteresis loop.

On the other hand, the high-cycle fatigue test is a fatigue test performed in such a manner that the maximum elastic strain generated in the test piece becomes sufficiently larger than the maximum plastic strain, contrary to the low-cycle fatigue test. When the fatigue test is performed under such conditions, the test piece is required to be 10 ³ -10
So-called high-cycle fatigue fracture, which requires ^four or more load application cycles, occurs. In the high cycle fatigue test, since only a small plastic strain is generated in the test piece, the hysteresis loop of the stress-strain diagram of the test piece has an elongated shape with a small area.

In the low-cycle fatigue test, while a load is repeatedly applied to the test piece, the load actually applied to the test piece at that time and the displacement generated in the load-applying portion applying the load to the test piece are measured. Alternatively, the elongation occurring in the test piece is measured, that is, sampling is performed as data. Then, the stress generated in the test piece is obtained from the measured load, and the strain generated in the test piece is obtained from the measured displacement or elongation. Further, a stress-strain diagram of the test piece is created based on the values of the stress and the strain, and various parameters relating to fatigue of the metal material are obtained by analyzing a hysteresis curve of the stress-strain diagram.

More specifically, data sampling is performed at a number of data points while the displacement or elongation of the test piece changes by one cycle.
This enables a stress-strain diagram to be created for each cycle of displacement or elongation. Then, from the hysteresis curve of the stress-strain diagram for each cycle,
Dynamic hardening index, Young's modulus, heat value per cycle or absorbed energy (which is equal to the loop area of the hysteresis curve), fatigue plasticity index, fatigue strength index, residual strain (ie, plastic strain), Elastic strain,
Then, the values of various parameters such as total strain are obtained, and the relationship between the values of those parameters and material fatigue is clarified.

The number of data points per cycle required to create a stress-strain diagram with sufficiently high accuracy that meets the purpose of such a low cycle fatigue test is usually several tens to Hundreds of thousands. In addition, in the low cycle fatigue test, in order to repeatedly apply a load to the test piece, control is performed to periodically change the displacement of the load applying portion for applying a load to the test piece or the elongation generated in the test piece. It is necessary to control the amplitude of the displacement or elongation with high precision from the first cycle of the periodic control.

The low-cycle fatigue test described below according to the embodiment of the present invention is based on the general properties of the low-cycle fatigue test described above. By periodically changing the displacement of the load section at a predetermined amplitude, a load is repeatedly applied to the test piece mounted on the material testing machine 12. In order to control the amplitude of the displacement with high precision, the above-described level comparison method is adopted, and data sampling is performed at a large number of data points while the displacement changes by one cycle.

It is the host computer 18 that executes this data sampling. Therefore, the host computer 18 and a program for data sampling loaded on the host computer 18 (this will be described later with reference to a flowchart). ) Constitute data sampling means. The data sampled by the data sampling means are the current value of the displacement, the current value of the load applied to the test piece, and the current value of the time at each data point.
The two values are set as a set for each data point and stored in the memory of the host computer 18 one after another. Further, based on the data thus stored, a hysteresis curve of a stress-strain diagram is created for each cycle later, and the hysteresis curve is analyzed.

Further, as described above, in the data sampling method of the present invention, data sampling is performed each time the controlled object output amount reaches each of a plurality of predetermined levels. In the description, it is called a sampling level. Also, in any of the embodiments described below, prior to the start of the low-cycle fatigue test, the host computer 18 calculates a large number of sampling levels in advance, and stores the calculated values of the sampling levels in its own memory. It is stored in the form of a look-up table, and this look-up table is called a sampling level table in the following description.

However, the creation of the sampling level table is not always necessary for the method of the present invention, and the sampling levels may be calculated one after another during the execution of the low cycle fatigue test.

Further, in order to facilitate understanding of the present invention,
Here, the low cycle fatigue test is performed in the following (1) to (4).
Shall be executed in accordance with the specifications listed in the above.

(1) During the execution of the test, the material testing machine 12
Is repeatedly moved periodically between an upper limit position Rmax and a lower limit position Rmin to apply a repetitive stress to the test piece. Therefore, the target amplitude of the displacement is (Rmax-Rmin). The value of the target amplitude is specified by the operator before the start of the test.

(2) The zero position of the movable-side load portion of the material testing machine 12 is defined by an upper limit position Rmin and a lower limit position Rm.
amax, and Rmax = −R
min.

(3) The maximum tensile strain εmax is generated in the test piece when the displacement reaches the upper limit position Rmax, and the maximum compressive strain εmin occurs in the test piece when the displacement reaches the lower limit position Rmin. Are substantially equal. Therefore, εmax = −εmin.

(4) As described above, a hysteresis curve of a stress-strain diagram was obtained from data collected while the displacement changed by one cycle, and based on the hysteresis curve, was the test piece broken? Judge whether
At this time, the number of data points per cycle necessary for making an accurate determination is Nreq.
The value of Nreq is specified by the operator prior to the start of the test. However, as will be described in detail later, an overshoot occurs in the displacement which is the control target output amount, and the data point corresponding to the overshoot portion is Nr.
Since the number of data points is added to eq data points, the number of data points per cycle at which data sampling is actually performed is several percent larger than Nreq data points.

As is clear from the above, from Rmin to R
The area up to max is the value range of the original target value for controlling the displacement, which is the control target output amount. Therefore, Rm
The region from in to Rmax is referred to as a target region in the following description. Further, as described above, since the displacement, which is the controlled object output amount, causes an overshoot, it slightly protrudes outside Rmax and Rmin. Therefore, the value range in which the displacement can actually take place includes the regions corresponding to the overshoots on both sides of the target region, and the regions on both sides are called overshoot regions in the following description.

The individual embodiments will now be described. In the data sampling method according to the first embodiment, the sampling levels are set at equal level intervals in the entire range of the value range in which the displacement can actually take, including the target area and the overshoot area. More specifically, for example, the operator
The number Nreq of data points per cycle is 10
When the number of data points is designated to 00, the sampling level of the target area may be set to 500 levels, and the number of data points per cycle is reduced to the designated number of 1000 and the overshoot area. Is added to the number of data points (this is a small number compared to 1000).

Further, in this case, the zero position of the displacement is the 0th level, the Rmax is the 250th level, the Rmin is the -250th level, and the level interval ΔD is ΔD = (Rmax−Rmin) / 500
By setting the level at equal level intervals, the sampling level can be set according to the specified displacement amplitude and the number of data points.

These processes relating to the sampling level setting are executed by the host computer 18. If the above processing is generalized and expressed, Rmax, R
When the values of min and Nreq are input from the operator, the host computer 18 first sets the level interval ΔD to ΔD = 2 × (Rmax−Rmin) / Nreq
Then, the n-th level L (n) is calculated as follows:
L (n) = n × ΔD is obtained and stored in the sampling level table one after another.

Further, at this time, since the sampling level is set not only in the target area but also in the overshoot area, for example, the area width of the overshoot area is expected to be at most 2% or less of the area width of the target area. Then, Rmin-1.02 x (Rmax-Rmin)
, The sampling level L (n) is obtained in a region from Rmax + 1.02 × (Rmax−Rmin).

As described above, setting of all necessary sampling levels is completed, other necessary parameters are designated by the operator, and necessary data and programs are transmitted from the host computer 18 to the digital signal processor 16. Loaded and test piece is a material testing machine 1
When properly mounted on No. 2, it is ready to start the low cycle fatigue test. Then, when the operator inputs a test start command to the host computer 18, the low cycle fatigue test is started.

Once the low cycle fatigue test has started,
The triangular wave signal generation control section 40 controls the target value signal generating section 26 to generate a target value signal Ds in the form of a triangular wave signal, whereby a stress is repeatedly applied to the test piece. And
The host computer 18 performs data sampling every time the displacement value represented by the sensor signal (= feedback signal) Ss reaches the sampling level stored in the sampling level table.

FIG. 6 is a flowchart showing an outline of a program of the host computer 18 for executing the data sampling. 6, first, the host computer 18 reads the sensor signal Ss (S142), obtains a sampling level L (n0) closest to the read sensor signal Ss, and sets a variable n to:
It is set to n = n0 (S144).

Subsequently, the sensor signal Ss is read again (S
146) If the read sensor signal Ss is larger than the sampling level L (n + 1) (S14)
8), because the displacement is at its sampling level L (n +
1) and has passed therethrough. Therefore, after performing data sampling, the variable n is changed to n
= N + 1 (S150).

On the other hand, if the sensor signal Ss read in step S146 is smaller than the sampling level L (n-1) (S152), it is determined that the displacement reaches the sampling level L (n-1) and The variable n is set to n = n−1 after performing data sampling (S15).
4).

In the step S156, it is checked whether or not the data sampling should be terminated. Then, in this step S156, the above-mentioned procedure from step S146 to step S154 is repeatedly executed until the routine for controlling the entire low cycle fatigue test indicates that data sampling should be terminated.

Therefore, as is clear from the above description,
The procedure shown in the flowchart of FIG.
Constitutes a level attainment determining means for determining whether or not the value of the displacement, which is the controlled object output amount, represented by (1) has reached each of a plurality of predetermined sampling levels.

FIG. 7A is a schematic diagram showing a hysteresis curve of a stress-strain diagram created based on data obtained by executing the data sampling method according to the first embodiment described above. FIG. 7B is a schematic diagram showing where a plurality of data points obtained by sampling data for creating the stress-strain diagram are located on the displacement waveform. In these figures, black circles in the figures represent data points.

Further, εmin and εm shown in FIG.
a represents the strain of the test piece when the displacement is at Rmin and Rmax, respectively. Rmin and Rmax
Are overshoot regions, and the outside of εmin and εmax are overshoot regions. In these figures, the overshoot regions are markedly exaggerated and widened. Further, the level interval ΔD of the sampling level
Is drawn much larger than the actual one.

As is apparent from FIGS. 7A and 7B, the first
According to the data sampling method according to the embodiment, even if the cycle cycle of the displacement changes significantly, the number of data points per cycle hardly changes. That is, the number of data points in the target area is always constant, and the number of data points in the overshoot area may fluctuate slightly, but the area width of the overshoot area is much smaller than the target area. , The variation in the number is small compared to the total number of data points per cycle. Therefore, the number of data points does not become too small or too large,
The number is always close to the appropriate number.

Further, according to the data sampling method according to the first embodiment, since a plurality of predetermined levels are set at equal level intervals, the set levels are stored in a lookup table and the next data level is stored. It is also easy to calculate the level at which sampling is performed by calculation.

However, in the data sampling method according to the first embodiment, in the hysteresis curve of FIG. 7A, the accuracy of the shape of the folded portion at the upper right and lower left corresponding to the overshoot region is not very good. Absent. On the other hand, depending on the material to be tested, it is necessary to represent the shape of this portion with high accuracy.

The data sampling method according to the second embodiment described below is a method suitable for testing such a material, and is similar to the method according to the first embodiment. However, the level interval of the sampling level in the overshoot area is set to be narrower than the level interval of the sampling level in the target area. Regarding this second embodiment,
FIGS. 8A and 8B correspond to FIGS. 7A and 7B, respectively.

In the data sampling method according to the second embodiment, when the sampling level table is created, the first area is set in the target area (Rmin to Rmax).
In the same manner as in the embodiment, the sampling level is set at the level interval ΔD. On the other hand, in the overshoot area outside the target area, the shape of the folded part at the upper right and lower left of the stress-strain diagram is sufficiently accurate. So that
The sampling level is set with a smaller level interval ΔD ′.

If the level setting is performed as described above, R
When the sampling level corresponding to max is the Nth level and the sampling level corresponding to Rmin is the −Nth level, a plurality of sampling levels are provided at equal level intervals from the −Nth level to the Nth level with a level interval ΔD. On the other hand, regarding the sampling level equal to or lower than the (-N-1) th level and the sampling level equal to or higher than the (N + 1) th level, a plurality of sampling levels are set at equal level intervals with a level interval ΔD ′ smaller than the level interval ΔD. The sampling level will be set.

The procedure for executing the data sampling method according to the second embodiment may be exactly the same as that of the first embodiment. Therefore, the procedure shown in the flowchart of FIG. 6 may be used. it can.

In the second embodiment, the number of data points per cycle is slightly larger than in the first embodiment, but the actual overshoot region width is exaggerated in the drawing. The number of data points in the overshoot region is much smaller than the number of data points in the target region, and is insignificant, as it is much narrower than that depicted. Therefore, when the second embodiment is adopted, the same advantage as that when the above-described first embodiment is adopted can be obtained. When the second embodiment is adopted, in addition to this, as is clear from FIGS. 8A and 8B, the shape of the folded portion at the upper right and lower left of the stress-strain diagram is highly accurate. Is obtained.

In the second embodiment, the level interval in the overshoot area is set to be smaller than the level interval in the target area. However, this is further generalized to an arbitrary area portion in the value range of the output amount to be controlled. May be set to a smaller level interval, so that
The resolution of the data in that region can be particularly improved. In addition, good results may be obtained by continuously changing and setting the level interval in the entire value range of the controlled object output amount. Depending on the specific application, setting the sampling levels at appropriate unequal level intervals may provide various advantages.

The data sampling method according to the third embodiment combines the level-based data sampling in the first and second embodiments with the time-based data sampling. In the target area, data sampling is performed every time a sampling level set at equal level intervals is reached, while in the overshoot area, data sampling is performed at predetermined time intervals instead of based on the level of displacement. Things. FIGS. 9A and 9B corresponding to FIGS. 7A and 8B or FIGS. 8A and 8B relating to the third embodiment are shown.

To execute the data sampling according to the third embodiment, only the sampling level of the target area needs to be set when the sampling level table is created, and the setting method of the sampling level of this area is as follows. , May be exactly the same as in the first and second embodiments. The data sampling in the overshoot region is performed at predetermined time intervals using the internal clock of the digital signal processing device 16. The procedure is shown in the flowcharts of FIGS.

First, in FIG. 10, step S14
Steps 2 ′ to S156 ′ show the procedure for executing data sampling in the target area. These steps are exactly the same as steps S142 to S156 in the flowchart of FIG. 6 described above. is there.

In the third embodiment, in step S162 inserted between steps S146 ′ and S148 ′, the sensor signal Ss read in step S146 ′ satisfies the condition of Rmin ≦ Ss ≦ Rmax. I'm trying to find out if it is. If this condition is satisfied, the current value of the displacement is within the target area.
Go to 8 '. On the other hand, if this condition is not satisfied, it indicates that the current value of the displacement is within the overshoot area, and in that case, the flow of processing proceeds to step S164.

Therefore, this step S162 is to determine whether or not the current value of the displacement, which is the controlled output amount, is in a region between the predetermined maximum value and the predetermined minimum value. Is composed.

In step S164, as shown in FIG. 11, the current value of the displacement deviates above the target area (Ss
> Rmax) or whether it is deviated downward, and a U / L flag for indicating the deviated direction is set (S166, S168). Subsequently, referring to a counter configured to count the internal clock of the digital signal processing device 16 and reset each time data sampling is performed, a predetermined time has elapsed since the last data sampling was performed. It is checked whether the interval ΔT has elapsed (S170), and if it has elapsed, data sampling is executed (S172). Note that this counter may be a hardware counter provided in the digital signal processing device 16, or may be realized by software by causing a CPU of the digital signal processing device 16 to execute necessary operations.

In the next step S174, it is checked whether or not a command indicating that data sampling should be terminated has been issued from a routine that supervises the entire low-cycle fatigue test. To end.

On the other hand, if such a command has not been issued, the sensor signal Ss is read again (S176), and the current value of the displacement represented by the sensor signal Ss is overshot. It is checked whether or not the area has returned to the target area (S178). Then, while the displacement is within the overshoot area, the procedure from step S170 to step S178 is repeatedly executed.

Therefore, in step S178, similarly to step S162 described above, it is determined whether or not the current value of the displacement, which is the output amount to be controlled, is in the area between the predetermined maximum value and the predetermined minimum value. This constitutes a control target output amount present value area determination means.

If the sensor signal Ss read in step S176 indicates that the current value of the displacement has returned to the target area, it means that the value of the displacement is Rmax
Through the limit sampling levels L (Nmax) to L (Nmin) respectively corresponding to Rmin to Rmin. Therefore, in this case, the host computer 18 executes data sampling (S
180), examine the U / L flag and find that the displacement
It is determined which of the two limit sampling levels has passed, and if the lower limit sampling level L
(Nmin), the variable n is changed to n = N
The variable n is set to min + 1 (S184), and if it has passed the upper limit sampling level L (Nmax), the variable n is set to n = Nmax-1. Thereafter, the processing flow returns to step S146 ', and data sampling is continued.

As described above, the actual width of the overshoot region is much smaller than the target region.
The time when the displacement is actually in the overshoot region is
Much shorter than the time in the target area. for that reason,
The number of data points in the overshoot region is much less than the number of data points in the target region. Therefore, when the third embodiment is adopted, the same advantages as those when the above-described second embodiment is adopted can be obtained. In particular, it is clear from FIGS. 9A and 9B that the shapes of the folded portions at the upper right and lower left of the stress-strain diagram can be obtained with high accuracy.

There are various materials to which the low cycle fatigue test can be applied. Which of the three embodiments disclosed above is the most suitable embodiment depends on the characteristics of the material to be tested. Further, modified embodiments of the embodiments disclosed above and still other embodiments may be suitable, and all of the embodiments included in the claims, including those, fall within the scope of the present invention. Is what you do.

[0152]

As described above, in the data sampling method according to the first aspect of the present invention, each of a controlled device and a plurality of sensor signals representing a plurality of output amounts of the controlled device are generated. A plurality of sensor systems, a feedback unit that uses one of the plurality of sensor signals as a feedback signal to make an output amount represented by the sensor signal a controlled object output amount, and a target of the controlled object output amount A target value signal generator that generates a target value signal representing a value, an error signal generator that generates a difference between the target value signal and the feedback signal as an error signal, and generates a control signal corresponding to the error signal. A feedback control system including a control signal generator, and increasing the value of the target value signal when the value of the control target output amount decreases to a predetermined minimum value. Controlling the target value signal generator so that the value of the target value signal starts to decrease when the value of the control target output amount increases to a predetermined maximum value, thereby controlling the control target output amount to the predetermined value. While repeatedly changing from a minimum value to the predetermined maximum value and from the predetermined maximum value to the predetermined minimum value, one or more output amounts of the plurality of output amounts of the controlled device are controlled. In the data sampling method for sampling as the data, data sampling is performed each time the value of the control target output amount reaches each of a plurality of predetermined levels.

According to this data sampling method, data sampling is performed every time the output of the controlled object repeatedly changing from the maximum value to the minimum value and from the minimum value to the maximum value reaches a predetermined level. The number of data points per cycle of the repetitive change of the output amount is not affected by the length of the cycle of the repetitive change, and therefore, the number of data points does not become too small or too large, and is always an appropriate number. Can be set to a number close to.

In the data sampling method according to the present invention, the plurality of predetermined levels are set at equal level intervals.

This is a method that can be suitably applied to many uses. By doing so, in addition to storing the set level in the look-up table, the predetermined level for the next data sampling can be obtained. Can also be easily calculated.

In the data sampling method according to the present invention, the plurality of predetermined levels are set at unequal level intervals.

For this reason, a small level interval is set for an important part of the value range of the controlled object output amount,
The resolution of the data in that portion can be increased.

According to a fourth aspect of the present invention, in the data sampling method according to the present invention, in a range between the predetermined maximum value and the predetermined minimum value in the value range of the controlled object output amount, a first level interval is provided. The plurality of predetermined levels are set at equal level intervals, and in a value range of the output amount of the control target, in a region deviating from a region between the predetermined maximum value and the predetermined minimum value, the value is smaller than the first level interval. The plurality of predetermined levels are set at equal level intervals with a second level interval.

Therefore, when this data sampling method is applied to a low cycle fatigue test using a material testing machine, the accuracy of an important part of a hysteresis curve of a stress-strain diagram created based on sampled data is improved. be able to.

According to a fifth aspect of the present invention, in the data sampling method of the present invention, in a range between the predetermined maximum value and the predetermined minimum value in the value range of the controlled object output amount, the data sampling method is provided at equal level intervals. A plurality of predetermined levels are set, and data sampling is performed at predetermined time intervals in a region out of a region between the predetermined maximum value and the predetermined minimum value in a value range of the control target output amount.

Therefore, when this data sampling method is applied to a low-cycle fatigue test using a material testing machine, a stress generated based on the sampled data is obtained in the same manner as the data sampling method described in claim 4. The accuracy of the important part of the hysteresis curve of the strain diagram can be improved.

Further, in the data sampling method according to the present invention, the controlled object device is a hydraulic material testing machine provided with a hydraulic actuator system, and the control of the target value signal generating section is performed by: Executed as a control for a low cycle fatigue test of a test piece mounted on the hydraulic material testing machine, an output amount related to a load applied to the test piece and an output amount related to a deformation amount generated in the test piece. Is sampled as data.

This shows a preferable object to which a particularly great advantage can be obtained by applying the data sampling method according to claims 1 to 5.

According to a seventh aspect of the present invention, in the data sampling method according to the present invention, the first output amount of the controlled device that generates a plurality of output amounts including the first output amount and the second output amount is feedback-controlled. And a data sampling method for sampling at least the second output amount of the plurality of output amounts as data, wherein data sampling is performed each time the value of the first output amount reaches each of a plurality of predetermined levels. I did it.

This clearly shows the excellent characteristics of the data sampling method according to the present invention.

According to the present invention, there is provided a control device having a data sampling function according to the present invention, wherein a plurality of sensor signals respectively representing a plurality of sensor signals representing a plurality of output amounts of the controlled object device are provided. Used in combination with a sensor system,
A control unit having a data sampling function, wherein one of the plurality of sensor signals is used as a feedback signal so that an output amount represented by the sensor signal is used as a control target output amount; A target value signal generator that generates a target value signal representing a target value of the output amount; an error signal generator that generates a difference between the target value signal and the feedback signal as an error signal; and control according to the error signal. A control signal generating unit that generates a signal, and starts increasing the value of the target value signal when the value of the controlled object output amount decreases to a predetermined minimum value, and increases the value of the controlled object output amount to a predetermined maximum value By controlling the target value signal generation unit so as to start decreasing the value of the target value signal when the control target output amount has reached the predetermined minimum value. A target value signal generator control means for repetitively changing from the predetermined maximum value to the predetermined maximum value and from the predetermined maximum value to the predetermined minimum value, and one of the plurality of output amounts of the controlled device. Data sampling means for sampling one or more output amounts as data, wherein the data sampling means determines whether or not the value of the controlled output amount has reached each of a plurality of predetermined levels. Equipped with arrival determination means,
Each time the level reaching determination means determines that the value of the controlled object output amount has reached each of the plurality of predetermined levels,
The control target device is configured to perform data sampling of the output amount.

According to the control device having the data sampling function, the data sampling is performed every time the control target output amount that repeatedly changes from the maximum value to the minimum value and from the minimum value to the maximum value reaches a predetermined level. Therefore, the number of data points per cycle of the repetitive change of the controlled object output amount is not affected by the length of the cycle of the repetitive change, and therefore the number of data points is not too small or too large. Instead, the number can always be close to the appropriate number.

In the control device having a data sampling function according to the ninth aspect of the present invention, the plurality of predetermined levels are set at equal level intervals.

This is a device that can be suitably applied to many uses. In such a device, in addition to storing the set level in a look-up table, a predetermined level for the next data sampling is used. Can also be easily calculated.

In the control device having a data sampling function according to the present invention, the plurality of predetermined levels are set at unequal level intervals.

For this reason, by setting a small level interval for an important part of the value range of the controlled object output amount,
The resolution of the data in that portion can be increased.

Further, in the control device having the data sampling function according to the present invention, in the range of the controlled object output amount between the predetermined maximum value and the predetermined minimum value, The plurality of predetermined levels are set at equal level intervals with a first level interval, and in a value range of the control target output amount, in a region outside a region between the predetermined maximum value and the predetermined minimum value, The plurality of predetermined levels are set at equal level intervals with a second level interval smaller than the first level interval.

Therefore, when the control device having the data sampling function is applied to a low cycle fatigue test using a material testing machine, the importance of the hysteresis curve of the stress-strain diagram created based on the sampled data is important. The accuracy of the part can be increased.

A control device having a data sampling function according to the present invention as set forth in claim 12, wherein in the range of the controlled object output amount, between the predetermined maximum value and the predetermined minimum value, The plurality of predetermined levels are set at equal level intervals, and the data sampling means further determines whether a current value of the controlled object output amount is in an area between the predetermined maximum value and the predetermined minimum value. Control target output amount current value region determining means for determining the value of the control target output amount, in a range outside the region between the predetermined maximum value and the predetermined minimum value, a predetermined time interval Is configured to perform data sampling.

Therefore, similarly to the control device having the data sampling function according to the eleventh aspect, when the control device having the data sampling function is applied to a low cycle fatigue test using a material testing machine, The accuracy of the important part of the hysteresis curve of the stress-strain diagram created based on the sampled data can be improved.

According to a thirteenth aspect of the present invention, there is provided a control device having a data sampling function according to the present invention, wherein the controlled object device is a hydraulic material testing machine having a hydraulic actuator system, and the target value signal generator Is executed as a control for a low-cycle fatigue test of a test piece mounted on the hydraulic material testing machine, and the output amount of the controlled device, which is sampled as data, is a load applied to the test piece. And the output amount related to the amount of deformation occurring in the test piece.

This shows a preferable object to which a particularly great advantage can be obtained by applying the control device having the data sampling function according to claims 8 to 12.

A control device having a data sampling function according to the present invention as defined in claim 14 is a control device which generates a plurality of output quantities including a first output quantity and a second output quantity. In a control device having a data sampling function, wherein at least the second output amount of the plurality of output amounts is sampled as data while performing feedback control of the output amount, the value of the first output amount may be a plurality of predetermined levels. Level determination means for determining whether or not each of the plurality of predetermined levels has been reached, and each time the level arrival determination means determines that the value of the first output amount has reached each of the plurality of predetermined levels, Is configured to perform data sampling of at least the second output amount of the output amounts.

This clearly shows the excellent features of the control device having the data sampling function according to the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram of a feedback control system suitable for carrying out a data sampling method according to a preferred embodiment of the present invention, including a control device having a data sampling function according to the preferred embodiment of the present invention; FIG.

FIG. 2 is a block diagram showing a specific example of a triangular wave signal generation control unit configured by wiring logic.

FIG. 3 is a flowchart illustrating a specific example of a triangular wave signal generation control unit implemented by software.

FIG. 4 is a flowchart showing a specific example of a configuration of a target value signal generator for operating in a level comparison mode.

FIG. 5A is a waveform diagram showing a result when the amplitude of the displacement, which is the output amount to be controlled, is controlled by controlling the target value signal generation unit by the triangular wave signal generation control unit using the level comparison method. FIG. 6B is a waveform diagram showing a result when a normal feedback control method is used for comparison.

FIG. 6 is a flowchart showing a data sampling method according to the first embodiment and the second embodiment of the present invention.

FIG. 7A is a schematic diagram showing a hysteresis curve of a stress-strain diagram created based on data obtained by executing the data sampling method according to the first embodiment of the present invention, and FIG. FIG. 5 is a schematic diagram showing where data points obtained by sampling data for creating the stress-strain diagram are located on the waveform of displacement.

FIGS. 8A and 8B are diagrams corresponding to FIGS. 7A and 7B according to the second embodiment of the present invention.

FIGS. 9A and 9B are diagrams corresponding to FIGS. 7A and 8B or FIGS. 8A and 8B relating to a third embodiment of the present invention; FIGS.

FIG. 10 is a flowchart illustrating a data sampling method according to a third embodiment of the present invention.

FIG. 11 is a flowchart illustrating a data sampling method according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Feedback control system 12 Hydraulic material testing machine 14a, 14b Sensor system 16 Digital signal processor 18 Host computer 26 Target value signal generation part 28 Error signal generation part 32 Control signal generation part 40 Triangular wave signal generation control part Ss Sensor signal (feedback Signal) Ds target value signal Es error signal Cs control signal

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2G061 AA01 AB01 AB05 AB10 BA06 DA03 DA12 EA01 EA02 EB03 EB05 5H004 GB20 HA07 HA11 HA16 HB07 HB11 JA05 JA23 JB09 JB10 JB19 KA36 LA15 MA09 MA34 MA60

Claims (14)

[Claims] 1. A control target device, a plurality of sensor systems respectively generating a plurality of sensor signals representing a plurality of output amounts of the control target device, and a feedback of one of the plurality of sensor signals A feedback unit configured to generate a control signal, the output amount represented by the sensor signal being a control target output amount, a target value signal generation unit generating a target value signal representing a target value of the control target output amount, and the target value signal An error signal generating unit that generates a difference between the error signal and the feedback signal, and a feedback control system including a control signal generating unit that generates a control signal according to the error signal, the control target output amount Starts increasing the value of the target value signal when the value of the target value signal decreases to a predetermined minimum value, and increases the value of the target value signal when the value of the control target output amount increases to a predetermined maximum value. By controlling the target value signal generation unit so as to start decreasing, the control target output amount is repeatedly changed from the predetermined minimum value to the predetermined maximum value, and from the predetermined maximum value to the predetermined minimum value. A data sampling method for sampling one or more output amounts of the plurality of output amounts of the control target device as data, wherein the value of the control target output amount is a plurality of predetermined values. A data sampling method, wherein data sampling is performed each time a level is reached. 2. The data sampling method according to claim 1, wherein said plurality of predetermined levels are set at equal level intervals. 3. The data sampling method according to claim 1, wherein said plurality of predetermined levels are set at unequal level intervals. 4. An area between the predetermined maximum value and the predetermined minimum value in the range of the controlled object output amount, wherein the plurality of predetermined levels are set at equal level intervals with a first level interval, In the range of the output amount of the controlled object, in a region deviating from the region between the predetermined maximum value and the predetermined minimum value, the plurality of predetermined levels at equal level intervals with a second level interval smaller than the first level interval. 2. The data sampling method according to claim 1, wherein 5. In a range between the predetermined maximum value and the predetermined minimum value in the range of the controlled object output amount, the plurality of predetermined levels are set at equal level intervals, 2. The data sampling method according to claim 1, wherein data sampling is performed at predetermined time intervals in an area out of an area between the predetermined maximum value and the predetermined minimum value in the value range. 6. The hydraulic material testing machine provided with a hydraulic actuator system, wherein the control target device controls the target value signal generating section by a low cycle of a test piece mounted on the hydraulic material testing machine. The method is executed as control for a fatigue test, and an output amount related to a load applied to the test piece and an output amount related to a deformation amount generated in the test piece are sampled as data. 6. The data sampling method according to claim 5. 7. A feedback control of the first output amount of a controlled device that generates a plurality of output amounts including a first output amount and a second output amount, and at least the first output amount of the plurality of output amounts. 2. A data sampling method for sampling an output amount as data, wherein the data sampling is performed each time the value of the first output amount reaches each of a plurality of predetermined levels. 8. A control device having a data sampling function, wherein a control target device and a plurality of sensor signals representing a plurality of output amounts of the control target device are used in combination with a plurality of sensor systems respectively generating the plurality of sensor signals. A feedback unit that uses one of the sensor signals as a feedback signal to make an output amount represented by the sensor signal a control target output amount; and generates a target value signal that indicates a target value of the control target output amount. A target value signal generator that generates a difference between the target value signal and the feedback signal as an error signal; a control signal generator that generates a control signal according to the error signal; When the value of the target output amount decreases to a predetermined minimum value, the value of the target value signal starts to increase, and the value of the control target output amount increases to a predetermined maximum value. By controlling the target value signal generation unit so as to start decreasing the value of the target value signal when the control target output amount from the predetermined minimum value to the predetermined maximum value, and the predetermined maximum value And a target value signal generation unit control means for repeatedly changing the output value to the predetermined minimum value, and sampling one or more output amounts of the plurality of output amounts of the controlled device as data. Data sampling means for determining whether or not the value of the controlled object output amount has reached each of a plurality of predetermined levels. Each time the level reaching determination unit determines that the value of the output amount has reached each of the plurality of predetermined levels, data sampling of the output amount of the control target device is performed. A control device having a data sampling function, which is configured as described above. 9. The control device according to claim 8, wherein the plurality of predetermined levels are set at equal level intervals. 10. The control device according to claim 8, wherein the plurality of predetermined levels are set at unequal level intervals. 11. In a range between the predetermined maximum value and the predetermined minimum value in the value range of the controlled object output amount, a first
The plurality of predetermined levels are set at equal level intervals with a level interval, and in a range of the output amount of the control target, in a region outside a region between the predetermined maximum value and the predetermined minimum value, 9. The control device with a data sampling function according to claim 8, wherein the plurality of predetermined levels are set at equal level intervals with a second level interval smaller than one level interval. 12. The plurality of predetermined levels are set at equal level intervals in an area between the predetermined maximum value and the predetermined minimum value in a range of the output amount of the control target. Further includes a control target output amount current value area determination unit that determines whether a current value of the control target output amount is in a region between the predetermined maximum value and the predetermined minimum value, In a value range of the target output amount, data sampling is performed at a predetermined time interval in a region deviating from a region between the predetermined maximum value and the predetermined minimum value. 9. A control device provided with the data sampling function according to 8. 13. The control target device is a hydraulic material testing machine having a hydraulic actuator system, and the control of the target value signal generating section is performed by a low cycle of a test piece mounted on the hydraulic material testing machine. The output amount of the controlled device, which is executed as control for a fatigue test and is sampled as data, is an output amount related to a load applied to the test piece and an output amount related to a deformation amount generated in the test piece. The control device having a data sampling function according to any one of claims 8 to 12, comprising: 14. A feedback control of the first output amount of a controlled device that generates a plurality of output amounts including a first output amount and a second output amount, and at least the first output amount of the plurality of output amounts. (2) A control device having a data sampling function for sampling the output amount as data, comprising: a level arrival determination unit configured to determine whether or not the value of the first output amount has reached each of a plurality of predetermined levels; Each time the level reaching determination unit determines that the value of the first output amount has reached each of the plurality of predetermined levels, data sampling of at least the second output amount of the plurality of output amounts is performed. A control device having a data sampling function, which is configured.