JP2004251825A - Material testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with work for finding the optimum gain for a testing condition by trial and error, and to improve workability. <P>SOLUTION: In this material testing machine 100, a changing speed of a stress or strain in a specimen is detected by a load cell 105 or an extensometer 106, and a pulse number P is determined based on a value of a deviation ΔV between a set target changing speed and a detected actual changing speed to control a rotating speed of a motor 1. A plurality of gain values is set tentatively therein to test the specimen respectively, a frequency q of the deviations ΔV is measured therein, and the pulse numbers P in the deviations ΔV are weight-averaged based on the measured frequency q to prepare a table of the deviations ΔV and the pulse numbers P. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

ただし、
Ｇ：試験機のゲイン
Γ：偏差ΔＶとゲインＧの乗算値
β：試験機ごとに固有の定数
【００１３】
テーブル作成モードを実行すると、まずゲインＧをある値に仮に設定する。このゲインはたとえばオペレータが任意に設定することができ、ここではたとえばＧ＝ｇ_１と設定する。このゲインにより供試体を試験し、ある時間間隔、たとえば５０ｍｓごとにサンプリングした偏差ΔＶについて、偏差ΔＶとゲイン値ｇ_１との乗算値Γ_１およびそのときに出力するパルス数Ｐ_１を測定する。
【００１４】
試験が終了したら、乗算値Γ_１とパルス数Ｐ_１の測定結果をテーブル化する。測定結果テーブルの例を図３（ａ）に示す。図３（ａ）の例では、時間ｔ１，ｔ２，ｔ３，ｔ４，・・・においてサンプリングされた偏差ΔＶ_１ ^ｔ１，ΔＶ_１ ^ｔ２，ΔＶ_１ ^ｔ３，ΔＶ_１ ^ｔ４，・・・について、乗算値Γ_１の測定結果Γ_１ ^ｔ１，Γ_１ ^ｔ２，Γ_１ ^ｔ３，Γ_１ ^ｔ４，・・・と、パルス数Ｐ_１の測定結果Ｐ_１ ^ｔ１，Ｐ_１ ^ｔ２，Ｐ_１ ^ｔ３，Ｐ_１ ^ｔ４，・・・がテーブル化されている。
【００１５】
乗算値Γ_１とパルス数Ｐ_１の測定結果をテーブル化したら、そのテーブルにおける偏差ΔＶのヒストグラムを作成し、ゲイン値ｇ_１のときの偏差ΔＶの頻度ｑ_１を算出する。図３（ａ）のテーブルにより作成されるヒストグラムの例を図３（ｂ）に示す。図３（ｂ）の例では、偏差ΔＶ_１，ΔＶ_２，ΔＶ_３，ΔＶ_４，・・・の頻度はそれぞれｑ_１ ^１，ｑ_１ ^２，ｑ_１ ^３，ｑ_１ ^４，・・・である。
【００１６】
頻度ｑ_１を算出したら、その頻度ｑ_１よりパルス数Ｐ_１に対する重み係数ｗ_１を算出する。重み係数ｗ_１は、下記の式（３）により算出される。このとき、オペレータの判断によって重み係数ｗ_１の値を調節してもよい。算出した重み係数ｗ_１は、頻度ｑ_１およびパルス数Ｐ_１とともに、偏差ΔＶの値ごとにテーブル化される。テーブル化した例を図３（ｃ）に示す。図３（ｃ）の例では、偏差ΔＶ_１，ΔＶ_２，ΔＶ_３，ΔＶ_４，・・・の頻度ｑ_１ ^１，ｑ_１ ^２，ｑ_１ ^３，ｑ_１ ^４，・・・ごとに算出された重み係数ｗ_１ ^１，ｗ_１ ^２，ｗ_１ ^３，ｗ_１ ^４・・・が、パルス数Ｐ_１ ^１，Ｐ_１ ^２，Ｐ_１ ^３，Ｐ_１ ^４，・・・とともにテーブル化されている。
【数３】

【００１７】
以上のようにして、ゲイン値ｇ_１における重み係数のテーブルを作成する。同様にして、ゲイン値を変えたときの重み係数テーブルをそのゲイン値ごとに作成する。このときのゲイン値および作成する重み係数テーブルの数は、オペレータが任意に設定できる。図４（ａ）〜（ｃ）に、ｇ_１とは別のゲイン値ｇ_２において重み係数テーブルを作成した例を示す。（ａ）は供試体の試験結果による乗算値Γ_２とパルス数Ｐ_２の測定結果テーブル、（ｂ）は（ａ）の測定結果テーブルによる偏差ΔＶのヒストグラム、（ｃ）は（ｂ）のヒストグラムより算出した重み係数テーブルの例をそれぞれ示している。
【００１８】
全てのゲイン値における重み係数テーブルを作成し終えたら、作成した重み係数テーブルにより、偏差ΔＶに対して出力すべきパルス数Ｐを算出する。出力すべきパルス数Ｐは、重み付け加重平均による下記の式（４）によって算出される。
【数４】

ただし、
ｍ ：作成した変数テーブルの数
ｗ_ｋ：ゲイン値ｇ_ｋのときの重み係数
Ｐ_ｋ：ゲイン値ｇ_ｋのときのパルス数
【００１９】
上記のようにして偏差ΔＶごとの出力すべきパルス数Ｐを算出したら、これを供試体の種類や試験条件とともにテーブル化する。図３（ｃ）および図４（ｃ）の重み係数テーブルにより出力すべきパルス数Ｐを算出し、これをテーブル化した例を図５に示す。図５の例では、行５１の偏差ΔＶの各値に対応するパルス数が供試体の種類ごとに各行にテーブル化されており、行５２に図３（ｃ）および図４（ｃ）により算出した７００７アルミのときのパルス数Ｐ_ｃがテーブル化されている。上記の式（４）により、この図５における出力すべきパルス数Ｐ_Ｃの値Ｐ_Ｃ ^１，Ｐ_Ｃ ^２，Ｐ_Ｃ ^３，Ｐ_Ｃ ^４，・・・は下記の式（５）で算出される。
【数５】
Ｐ_Ｃ＝（ｗ_１・Ｐ_１＋ｗ_２・Ｐ_２）／（ｗ_１＋ｗ_２） ・・・・（５）
【００２０】
作成した偏差ΔＶと出力すべきパルス数Ｐのテーブルは、データベースとして図１のメモリカード１０８に記憶する。また、このテーブルを作成するのに用いた重み係数テーブルも合わせて記憶する。これらのテーブルを記憶すると、テーブル作成モードを終了する。
【００２１】
（Ｂ）テストモード
テストモードでは、テーブル作成モードで作成した偏差ΔＶと出力すべきパルス数Ｐのテーブルを用いて、供試体に対する負荷試験を実施する。さらに、負荷試験の結果を反映してテーブルを更新する。
【００２２】
テストモードを実行すると、まず使用する偏差ΔＶと出力すべきパルス数Ｐのテーブルを選択する。これは、たとえば供試体の種類や試験条件を指定することで、記憶されたデータベースより自動的に検索して選択してもよいし、あるいはデータベースよりオペレータが選択してもよい。選択した偏差ΔＶと出力すべきパルス数Ｐのテーブルにより、検出したモータ速度の偏差ΔＶの値に対して出力するパルス数Ｐが決定され、材料試験機１００のモータ１が制御される。このようにして試験が行われる。
【００２３】
試験の終了後には、試験の実施結果により、テーブル作成モードで作成した重み係数テーブルと同様の重み係数テーブルを作成する。テストモードの試験結果により重み係数テーブルを作成したら、このテストモードで作成した重み係数テーブルと、前述のテーブル作成モードで作成した重み係数テーブルとを用いて、偏差ΔＶと出力すべきパルス数Ｐのテーブルを更新する。このときの方法は、前述のテーブル作成モードにおける方法と同様である。すなわち、テストモードとテーブル作成モードのそれぞれで作成した重み係数テーブルにより、偏差ΔＶに対して出力すべきパルス数Ｐを上記の式（４）を用いて算出する。
【００２４】
テストモードで作成した重み係数テーブルおよび更新した偏差ΔＶと出力すべきパルス数Ｐのテーブルは、図１のメモリカード１０８に記憶される。ここで更新したテーブルにより、次に実施する試験における偏差ΔＶに対して出力するパルス数Ｐを決定する。さらに、その試験結果によっても同様にして偏差ΔＶと出力すべきパルス数Ｐのテーブルを更新する。テストモードを実行している間は、このようにして処理を繰り返し実施し、テーブルを逐次更新する。
【００２５】
以上説明したようにして、テーブル作成モードとテストモードを行う。このようにすることで、あらかじめゲイン値を調節しなくても試験を実施することができ、さらに試験の実施結果を逐次反映して、より適切にモータ１の制御を行うことができる。
【００２６】
なお上述した材料試験機では、テーブル作成モードにおいて、サンプリングされた偏差ΔＶのヒストグラムを作成することを説明したが、このとき値が一定範囲内にあるものごとにグループ化し、このグループのヒストグラムを作成することとしてもよい。この場合、それぞれのグループに対応するパルス数の値は、そのグループに含まれる偏差ΔＶに対応するパルス数の値によって決定される。たとえば、対応するパルス数全体の平均値や最頻値としてもよく、あるいはそのグループ内での頻度に基づいて加重平均した値により決定してもよい。
【００２７】
上述した材料試験機では、はじめにテーブル作成モードにより偏差ΔＶと出力すべきパルス数Ｐの関係を決定し、その関係を用いてテストモードにより試験を実施することとしたが、テーブル作成モードを省略してもよい。この場合、あらかじめ設定された偏差ΔＶと出力すべきパルス数Ｐのテーブルを用いてテストモードを実施し、その実施結果を反映してテーブルを逐次更新していくようにする。
【００２８】
上述した材料試験機では、モータをサーボモータ１、検出手段をロードセル１０５、変位計１０６およびＣＰＵ１０１で実現し、駆動手段、テーブル作成手段、設定手段および更新手段をＣＰＵ１０１で実現している。しかし、これらはあくまで一例であり、本発明の特徴が損なわれない限り、各構成要素は上記実施の形態に限定されない。
【００２９】
【発明の効果】
以上説明したように本発明によれば、供試体の応力または歪みの変化速度を検出し、設定された供試体の目標変化速度と、検出された供試体の実変化速度との偏差に基づいてモータ駆動信号をモータへ供給し、偏差に対するモータ駆動信号のテーブルを供試体の材料ごとに作成し、作成された複数のテーブルの中から、供試体の材料に適したテーブルを設定し、設定されたテーブルから偏差を用いて算出されたモータ駆動信号をモータへ供給する。このようにしたので、あらかじめ偏差に対するモータ駆動信号のゲイン値を調節しなくても試験を実施することができ、作業性を改善できる。
また、テーブルを用いて行った試験中にサンプリングした偏差に対するモータ駆動信号に基づいてテーブルを更新するようにしたので、試験の実施結果を逐次反映してテーブルを更新し、より適切にモータの制御を行うことができる。
さらに本発明によれば、第１のゲインを用いて供試体を負荷しながら偏差に対するモータ駆動信号をサンプリングし、第１のゲインにおける偏差ごとの頻度分布に基づいて偏差に対するモータ駆動信号に重み付けをする。さらに、第２のゲインを用いて供試体を負荷しながら偏差に対するモータ駆動信号をサンプリングし、第２のゲインにおける偏差ごとの頻度分布に基づいて偏差に対するモータ駆動信号に重み付けをする。第１および第２のゲインによる重み付け後のモータ駆動信号を加重平均して偏差とモータ駆動信号とのテーブルを作成するようにした。このようにしたので、供試体ごとにそれぞれ適した偏差とモータ駆動信号とのテーブルを作成することができる。
また本発明によれば、テーブルを用いて行った試験中にサンプリングした偏差に対するモータ駆動信号に基づいて、偏差ごとの頻度分布に基づいて偏差に対するモータ駆動信号に重み付けをし、試験に使用したテーブルの偏差に対するモータ駆動信号と、試験中に重み付けしたモータ駆動信号を加重平均して、偏差とモータ駆動信号とのテーブルを更新するようにした。このようにしたので、試験の実施結果を逐次反映してテーブルを更新し、より適切にモータの制御を行うことができる。
【図面の簡単な説明】
【図１】本実施の形態の材料試験機の概略構成を示すブロック図
【図２】材料試験機の構造を模式的に示す図
【図３】テーブル作成モードにおいてゲイン値ｇ_１のときに作成されるテーブルとヒストグラムの例を示す図であり、（ａ）は試験の測定結果テーブルの例、（ｂ）は偏差ΔＶのヒストグラムの例、（ｃ）は重み係数テーブルの例をそれぞれ示す
【図４】テーブル作成モードにおいてゲイン値ｇ_２のときに作成されるテーブルとヒストグラムの例を示す図であり、（ａ）は試験の測定結果テーブルの例、（ｂ）は偏差ΔＶのヒストグラムの例、（ｃ）は重み係数テーブルの例をそれぞれ示す。
【図５】偏差ΔＶと出力すべきパルス数Ｐをテーブル化した例を示す図
【符号の説明】
１：モータ １００：材料試験機
１０１：ＣＰＵ １０２：ＲＯＭ
１０３：ＲＡＭ １０４：Ｄ／Ａ変換器
１０５：ロードセル １０６：伸び計
１０７：Ａ／Ｄ変換器 １０８：メモリカード
１０９：カードリーダ[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a material testing machine for loading a specimen such as metal, rubber, food or the like with a motor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a material testing machine which evaluates a specimen by applying a tensile load or a compressive load to the specimen by driving a pair of screw rods by a servomotor. In such a material testing machine, when performing the constant stress increase rate control, the stress is detected, the deviation between the target stress increase rate and the stress increase rate calculated from the detected stress is calculated, and this deviation is zero. Control the servo motor so that In the case of constant strain increase rate control, the strain is detected, the deviation between the target strain increase rate and the strain increase rate calculated from the detected strain is calculated, and the servomotor is controlled so that the deviation becomes zero. I do.
[0003]
[Problems to be solved by the invention]
In a conventional material testing machine, a gain is set in accordance with a test condition, and a command value to be input to a motor is calculated based on the following equation (1) using the above-described deviation and a preset gain.
(Equation 1)
Command value P = deviation ΔV × gain G × constant α (1)
[0004]
However, the constant α is a value set in hardware in the material testing machine, and cannot be changed by the user. Therefore, in order to find the optimum gain for the test condition, it is essential to find the optimum gain by trial and error before the test, and there is a demand for improving the workability.
[0005]
The present invention provides a material testing machine that improves workability.
[0006]
[Means for Solving the Problems]
A material testing machine according to the present invention includes a motor for loading a specimen, detection means for detecting a rate of change in stress or strain of the specimen, a target rate of change of a set specimen, and detection by the detection means. Driving means for supplying a motor drive signal to the motor based on the deviation from the actual change speed of the specimen, table creation means for creating a table of the motor drive signal for the deviation for each material of the specimen, and table creation means. Setting means for setting a table suitable for the material of the specimen from among the plurality of created tables, and the driving means supplies a motor drive signal calculated using a deviation from the set table to the motor. Is what you do.
According to a second aspect of the present invention, in the material testing machine of the first aspect, an updating means for updating the table based on a motor drive signal for a deviation sampled during a test performed using the table is further provided.
According to a third aspect of the present invention, there is provided a motor for loading a specimen, a detecting means for detecting a speed at which the stress or strain of the specimen changes, a set target changing speed of the specimen, and the detecting means. A driving means for supplying a motor drive signal to the motor based on the deviation from the actual change speed of the specimen, and a table preparation means for preparing a table of the motor drive signal with respect to the deviation for each material of the specimen. The means (1) samples the motor drive signal for the deviation while loading the specimen using the first gain, and weights the motor drive signal for the deviation based on the frequency distribution for each deviation in the first gain. And (2) sampling the motor drive signal for the deviation while loading the specimen using the second gain, and based on the frequency distribution for each deviation in the second gain. And (3) a weighted average of the motor drive signals weighted by the first and second gains to create a table of the deviation and the motor drive signal. A motor drive signal calculated using the deviation from the table obtained is supplied to the motor.
According to a fourth aspect of the present invention, in the material testing machine of the third aspect, (1) the motor for the deviation based on the frequency distribution for each deviation based on the motor drive signal for the deviation sampled during the test performed using the table. Updating means for weighting the drive signal and (2) weighting and averaging the motor drive signal for the deviation of the table used for the test and the motor drive signal weighted during the test, and updating the table of the deviation and the motor drive signal Is further provided.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
-1st Embodiment-
FIG. 1 is a block diagram showing a schematic configuration of the material testing machine of the present embodiment. The material testing machine 100 shown in FIG. 1 drives the servomotor 1 to perform a tension or compression test or the like. The material testing machine 100 has a CPU 101, a ROM 102, a RAM 103, a D / A converter 104, a load cell 105, an extensometer 106, an A / D converter 107, a memory card 108, and a card reader 109 in addition to the motor 1.
[0008]
The CPU 101 performs various operations by executing a program stored in the ROM 102 using the RAM 103 as a work area. The CPU 101 controls the motor 1 by outputting a motor drive signal to the D / A converter 104.
[0009]
Data measured by the load cell 105 for measuring the load applied to the sample and the extensometer 106 for measuring the deformation of the sample due to the load are output to the A / D converter 107 by analog signals. The measurement data converted into a digital signal by the A / D converter 107 is output to the CPU 101. The CPU 101 detects the rate of change of the stress or strain of the sample from the measurement data, and, based on the deviation ΔV between the detection result and the target rate of change set as a test condition, generates a D / A converter 104 as a motor drive signal. Is determined. The motor drive signal having the pulse number P is converted into an analog signal by the D / A converter 104, and then output to the motor 1 to drive the motor 1 at a speed corresponding to the pulse number P. The CPU 101 also outputs the measurement data to the card reader 109 that controls reading and writing of the memory card 108, and stores the measurement data in the memory card 108.
[0010]
FIG. 2 is a diagram schematically showing a structure of a portion for loading a sample in the material testing machine 100 of FIG. The material testing machine 100 includes a pair of screw rods 32 erected on a table 31, a crosshead 33 screwed to the screw rods 32, and the servomotor 1 for rotating and driving the screw rods 32. The head 33 is provided with a grip 34 via a load cell 105, and the table 31 is provided with a lower grip 35. The rotation of the motor 1 is transmitted to the pair of screw rods 32 via the drive gear train 38, and the rotation of the screw rods 32 raises and lowers the crosshead 33 to load the specimen 37. The elongation of the specimen 37 is detected by the extensometer 106.
[0011]
The number of pulses P output as a motor drive signal from the CPU 101 is determined by the value of the deviation ΔV. Even if the value of the deviation ΔV is the same, the value of the number of pulses P determined by the test conditions and the type of the specimen is different. Therefore, it is difficult to set an optimal value of the pulse number P for a certain value of the deviation ΔV in advance. In order to solve this, the present embodiment has the following two modes.
(A) Table creation mode: a mode in which the value of the number of pulses P is first determined with respect to the value of the deviation ΔV under a certain test condition. (B) Test mode: a test is performed based on the relationship between the deviation ΔV determined in the table creation mode and the number of pulses P. The modes in which the test results are further reflected in the relationship between the deviation ΔV and the number of pulses P will be described below in detail. In the following, a description will be given of a case where a test specimen is tested with a constant stress increase rate control.
[0012]
(A) Table creation mode In the table creation mode, the value of the number of pulses P to be output with respect to the value of the deviation ΔV is determined using a specific material, for example, 7007 aluminum as a specimen. That is, in this mode, a table of the number of pulses corresponding to the deviation ΔV between the target stress increase rate and the actual stress increase rate detected by the load cell 105 is created for each material of the specimen. Here, the pulse number P is represented by the following equation (2) by the deviation ΔV.
(Equation 2)

However,
G: Gain of test machine 機: Multiplied value of deviation ΔV and gain G β: Constant unique to each test machine
When the table creation mode is executed, the gain G is temporarily set to a certain value. The gain for example allow the operator to set arbitrarily, set here, for example G = g ₁ and. The gain by testing the specimen, the time interval that is, the deviation ΔV sampled e.g., every 50 ms, measures the number of pulses P ₁ to be output when the multiplication value gamma ₁ and the deviation ΔV and the gain value g _1.
[0014]
Once the test is completed, the table of the measurement result of the multiplication value gamma ₁ and the pulse number P _1. FIG. 3A shows an example of the measurement result table. In the example of FIG. 3A, the multiplication value Γ is obtained for the deviations ΔV ₁ ^t1 , ΔV ₁ ^t2 , ΔV ₁ ^t3 , ΔV ₁ ^t4 ,... Sampled at times t1, t2, t3, t4,. ₁ measurements ^{_{Γ 1 t1, Γ 1 t2,}} Γ 1 t3, Γ 1 t4, ··· and, measurements _P ¹ t1 pulse number ^{_{P 1, P 1 t2, P}} 1 t3, P 1 t4, ··・ It is tabulated.
[0015]
After the table the measurement results of the multiplication value gamma ₁ and the pulse number P _1, a histogram of deviations ΔV in the table, calculates the frequency q ₁ deviation ΔV when the gain value g _1. FIG. 3B shows an example of a histogram created by the table shown in FIG. In the example of FIG. 3 (b), the deviation _{ΔV 1, ΔV 2, ΔV 3} , ΔV 4, each frequency ^{_{··· q 1 1, q 1 2}} , q 1 3, q 1 4, is ... .
[0016]
After calculating the frequency _{q 1,} it calculates the weighting coefficients _{w 1} than the frequency _{q 1} to the pulse number _{P 1.} Weighting coefficients _{w 1} is calculated by the following formula (3). This time may be adjusted the value of the weight coefficients w ₁ by the operator's discretion. Calculating weighting coefficients w ₁ that, along with the frequency q ₁ and the number of pulses P _1, are tabulated for each value of the deviation [Delta] V. FIG. 3C shows an example of the table. In the example of FIG. 3 (c), the deviation _{ΔV 1, ΔV 2, ΔV 3} , ΔV 4, the frequency of ^{_{··· q 1 1, q 1 2}} , q 1 3, q 1 4, it is calculated for each ... weight coefficient ^{_{w 1 1, w 1 2,}} w 1 3, w 1 4 ··· is, the number of pulses ^{_{P 1 1, P 1 2,}} P 1 3, P 1 4, are tabulated together with ... .
[Equation 3]

[0017]
As described above, creating a weighting coefficient table in the gain value g _1. Similarly, a weight coefficient table when the gain value is changed is created for each gain value. At this time, the operator can arbitrarily set the gain value and the number of weight coefficient tables to be created. Figure 4 (a) ~ (c) , shows an example of creating a weighting coefficient table in another gain value _{g 2} and _{g 1.} (A) the measurement result table multiplication value gamma ₂ and the pulse number P ₂ by specimen test results, (b) is a histogram of the deviation ΔV by the measurement result table (a), the histogram of (c) is (b) Each example of the weight coefficient table calculated by the above is shown.
[0018]
When the weight coefficient tables for all the gain values have been created, the number of pulses P to be output for the deviation ΔV is calculated from the created weight coefficient tables. The number of pulses P to be output is calculated by the following equation (4) using a weighted weighted average.
(Equation 4)

However,
m: number of variables table that was created _{w k:} the weighting factor at the time of the gain value _{g k P k:} the number of pulses [0019] when the gain value _{g k}
After calculating the number of pulses P to be output for each deviation ΔV as described above, this is tabulated together with the type of test specimen and test conditions. FIG. 5 shows an example in which the number of pulses P to be output is calculated from the weighting coefficient tables of FIGS. 3C and 4C, and this is tabulated. In the example of FIG. 5, the number of pulses corresponding to each value of the deviation ΔV in the row 51 is tabulated in each row for each type of the specimen, and is calculated in the row 52 according to FIGS. 3C and 4C. The number of pulses _{Pc for} 7007 aluminum is tabulated. The above equation (4), the value _P ^C 1 pulse number _{P C} to be output in FIG. _5, ^P C ^_2, P C _3, ^{P C} 4, · · · is calculated by the following formula (5) You.
(Equation 5)
P _C = (w ₁ · P ₁ + w ₂ · P ₂ ) / (w ₁ + w ₂ ) (5)
[0020]
The table of the created deviation ΔV and the number of pulses P to be output is stored in the memory card 108 of FIG. 1 as a database. In addition, the weight coefficient table used to create this table is also stored. When these tables are stored, the table creation mode ends.
[0021]
(B) Test Mode In the test mode, a load test is performed on the specimen using a table of the deviation ΔV and the number of pulses P to be output created in the table creation mode. Further, the table is updated to reflect the result of the load test.
[0022]
When the test mode is executed, a table of the deviation ΔV to be used and the number P of pulses to be output is selected. This may be performed by automatically retrieving and selecting from a stored database, for example, by designating the type of test specimen and test conditions, or by an operator from the database. Based on the table of the selected deviation ΔV and the number of pulses P to be output, the number of pulses P to be output for the detected value of the deviation ΔV of the motor speed is determined, and the motor 1 of the material testing machine 100 is controlled. The test is performed in this way.
[0023]
After the end of the test, a weight coefficient table similar to the weight coefficient table created in the table creation mode is created based on the result of the test. After the weight coefficient table is created based on the test results in the test mode, the deviation ΔV and the number of pulses P to be output are calculated using the weight coefficient table created in the test mode and the weight coefficient table created in the above-described table creation mode. Update the table. The method at this time is the same as the method in the table creation mode described above. That is, the number of pulses P to be output with respect to the deviation ΔV is calculated using the above equation (4), based on the weight coefficient tables created in each of the test mode and the table creation mode.
[0024]
The weight coefficient table created in the test mode and the table of the updated deviation ΔV and the number of pulses P to be output are stored in the memory card 108 of FIG. Based on the updated table, the number of pulses P to be output for the deviation ΔV in the next test to be performed is determined. Further, the table of the deviation ΔV and the number of pulses P to be output is similarly updated based on the test result. While the test mode is being executed, the processing is repeatedly performed in this manner, and the table is sequentially updated.
[0025]
The table creation mode and the test mode are performed as described above. By doing so, the test can be performed without adjusting the gain value in advance, and the motor 1 can be more appropriately controlled by sequentially reflecting the test results.
[0026]
In the above-described material testing machine, it has been described that the histogram of the sampled deviation ΔV is created in the table creation mode. However, at this time, the values are grouped into those within a certain range, and the histogram of this group is created. You may do it. In this case, the value of the number of pulses corresponding to each group is determined by the value of the number of pulses corresponding to the deviation ΔV included in the group. For example, the average value or the mode value of the whole number of corresponding pulses may be used, or the value may be determined based on a weighted average value based on the frequency in the group.
[0027]
In the above-described material testing machine, first, the relationship between the deviation ΔV and the number of pulses P to be output is determined in the table creation mode, and the test is performed in the test mode using the relationship, but the table creation mode is omitted. You may. In this case, the test mode is performed using a table of a preset difference ΔV and the number of pulses P to be output, and the table is updated successively by reflecting the result of the test.
[0028]
In the above-described material testing machine, the motor is realized by the servomotor 1, the detecting means is realized by the load cell 105, the displacement meter 106 and the CPU 101, and the driving means, table creating means, setting means and updating means are realized by the CPU 101. However, these are merely examples, and each component is not limited to the above-described embodiment as long as the features of the present invention are not impaired.
[0029]
【The invention's effect】
As described above, according to the present invention, the rate of change of stress or strain of a specimen is detected, and based on a deviation between the set target rate of change of the specimen and the detected actual rate of change of the specimen. The motor drive signal is supplied to the motor, a table of the motor drive signal with respect to the deviation is created for each material of the specimen, and a table suitable for the material of the specimen is set from the plurality of created tables, and the table is set. The motor drive signal calculated using the deviation from the table is supplied to the motor. With this configuration, the test can be performed without adjusting the gain value of the motor drive signal with respect to the deviation in advance, and the workability can be improved.
Also, since the table is updated based on the motor drive signal corresponding to the deviation sampled during the test using the table, the table is updated by sequentially reflecting the test execution results, and the motor control is more appropriately performed. It can be performed.
Further, according to the present invention, the motor drive signal for the deviation is sampled while loading the specimen using the first gain, and the motor drive signal for the deviation is weighted based on the frequency distribution for each deviation in the first gain. I do. Further, the motor drive signal for the deviation is sampled while loading the specimen using the second gain, and the motor drive signal for the deviation is weighted based on the frequency distribution for each deviation in the second gain. The motor drive signal weighted by the first and second gains is weighted and averaged to create a table of the deviation and the motor drive signal. With this configuration, it is possible to create a table of the deviation and the motor drive signal suitable for each specimen.
Further, according to the present invention, based on the motor drive signal for the deviation sampled during the test performed using the table, the motor drive signal for the deviation is weighted based on the frequency distribution for each deviation, the table used for the test The motor drive signal corresponding to the deviation and the motor drive signal weighted during the test are weighted and averaged, and the table of the deviation and the motor drive signal is updated. With this configuration, the table can be updated by sequentially reflecting the test results, and the motor can be controlled more appropriately.
[Brief description of the drawings]
Created when the block diagram Figure 2 Figure 3 shows the structure of a material testing machine shown schematically table creating mode of the gain value g ₁ shown FIG. 1 a schematic structure of a material testing machine of the embodiment FIGS. 7A and 7B are diagrams showing an example of a table and a histogram, wherein FIG. 7A shows an example of a test measurement result table, FIG. 7B shows an example of a histogram of a deviation ΔV, and FIG. 4 is a view showing an example of a table and the histogram created when the gain value g ₂ in the table creating mode, (a) shows the example of the measurement result table of the test, (b) the example of the histogram of the deviation [Delta] V, (C) shows an example of the weight coefficient table.
FIG. 5 is a diagram showing an example in which a deviation ΔV and the number of pulses P to be output are tabulated.
1: Motor 100: Material testing machine 101: CPU 102: ROM
103: RAM 104: D / A converter 105: Load cell 106: Extensometer 107: A / D converter 108: Memory card 109: Card reader

Claims (4)

A motor for loading the specimen,
Detecting means for detecting the rate of change of the stress or strain of the specimen,
A driving unit that supplies a motor drive signal to the motor based on a deviation between the set target change speed of the specimen and an actual change speed of the specimen detected by the detection unit; and the motor drive signal for the deviation. Table creation means for creating a table for each material of the specimen,
From among the plurality of tables created by the table creation means, setting means to set a table suitable for the material of the specimen,
The material testing machine, wherein the driving unit supplies a motor driving signal calculated from the set table using the deviation to the motor. The material testing machine according to claim 1,
A material testing machine further comprising: an updating unit that updates the table based on a motor drive signal for a deviation sampled during a test performed using the table. A motor for loading the specimen,
Detecting means for detecting the rate of change of the stress or strain of the specimen,
Driving means for supplying a motor drive signal to the motor based on a deviation between the set target change speed of the specimen and the actual change speed of the specimen detected by the detection means,
Table creating means for creating a table of the motor drive signal for the deviation for each material of the specimen,
The table creation means,
(1) sampling a motor drive signal for a deviation while loading the specimen using a first gain, and weighting the motor drive signal for the deviation based on a frequency distribution for each deviation in the first gain;
(2) A motor drive signal for the deviation is sampled while loading the specimen using the second gain, and the motor drive signal for the deviation is weighted based on a frequency distribution for each deviation in the second gain. ,
(3) A table of the deviation and the motor drive signal is created by performing a weighted average of the motor drive signal after the weighting by the first and second gains,
The material testing machine, wherein the driving unit supplies a motor driving signal calculated from the set table using the deviation to the motor. The material testing machine according to claim 3,
(1) weighting the motor drive signal for the deviation based on a frequency distribution for each deviation based on the motor drive signal for the deviation sampled during a test performed using the table;
(2) An update means for updating a table of the deviation and the motor drive signal by performing a weighted average of the motor drive signal for the deviation of the table used for the test and the motor drive signal weighted during the test. And material testing machine.

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