JP3255471B2 - Control device for material testing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for a material testing machine, and more particularly to a fixed table and a crosshead that moves up and down with respect to the fixed table. (A) a test pattern in which a test specimen is loaded while a crosshead is driven at a constant speed, or (b) a load speed or distortion of the test specimen. The present invention relates to a control device for controlling a test to be performed with a test pattern in which a test piece is loaded at a constant speed.

[0002]

2. Description of the Related Art Conventionally, as a control device of this type, a control device as shown in FIG. 7 is disclosed, for example, in Japanese Utility Model Laid-Open No. 2-77656. In the figure, the speed of the crosshead is detected as a pulse train by a rotary encoder 2 directly connected to a motor 1 for driving the crosshead, the load applied to the test piece is detected as an analog value by a load cell 3 attached to the crosshead, and The strain of the test piece is detected as an analog value by the strain gauge 4 attached to the test piece.
A crosshead speed setting device 6 for setting a target speed of the crosshead according to an input operation from the operation panel 5.
And a load speed setting device 7 for setting the load speed, and a strain setting device 8 for setting the strain speed of the test piece. Each of the setting devices 6 to 8 is set according to the test patterns a and b. Set value and rotary encoder 2, load cell 3,
A deviation is obtained by comparing each detection output from the strain gauge 4, and the drive of the crosshead driving motor 1 is controlled in accordance with the deviation.

That is, when the test pattern (a) is selected, the common contact of the switches SW1 to SW3 is switched to the contact 1. The crosshead speed setting device 6 outputs to the pulse generator 9 a signal for generating a pulse train of a number corresponding to the target speed, and outputs an up signal and a down signal in accordance with the tension and compression. The up signal and the down signal output from the crosshead speed setting unit 6 are input to the up input U and the down input D of the counter 10 and the pulse input from the pulse generator 9 to the clock input CK of the counter 10. Signal counts up,
Counted down.

Further, a pulse signal is generated from the rotary encoder in accordance with the rotation of the motor 1 for driving the crosshead, and a down signal and an up signal are generated in accordance with the direction of rotation. The pulse signal is input to the clock input CK of the counter, the down signal is input to the down input D, and the up signal is input to the up input U. The count value of the counter 10 is converted into an analog signal by the D / A converter 11, and the switch SW 1 and the drive amplifier 12
Is sent as a drive signal to the motor 1 via the. Thereby, the motor 1 rotates so that the crosshead moves up and down at the set target speed, and the test piece is loaded.

When the test pattern (b) is selected, the common contact c of the switches SW1 to SW3 is switched to the contact 2 or 3. When the contact is switched to the contact 2, an analog signal from the load speed setting device 7 and a load detection analog signal output from the load cell 3 via the load amplifier 13 are input to the deviation calculator 14, respectively. Deviations are taken. This deviation signal is output from the switch SW
1 and to the motor 1 via the drive amplifier 12.
Thereby, the crosshead is raised and lowered so that the load applied to the test piece increases at the set load speed.

Similarly, when the contact is switched to the contact 3, the motor 1 is controlled in accordance with the deviation between the analog signal from the strain rate setting device 8 and the analog signal for strain detection output from the strain gauge 4 via the strain gauge amplifier 15. Is driven, whereby the crosshead is driven such that the strain rate is constant.

[0007]

In the conventional apparatus described above, in setting the crosshead speed, it is sufficient to set how many pulse trains are to be generated according to the target speed, and a digital setter can be used. However, as the setting devices 7 and 8 for setting the load speed and the strain speed, respectively, it is necessary to use analog type setters that generate analog signals that increase or decrease according to the load speed or the strain speed.

[0008] By the way, this type of analog setting device is susceptible to aging and the setting accuracy is poor at 2-3%.
Since the speed accuracy is determined by the set accuracy, the analog speed accuracy has to be 2-3%. Further, since the setting operation for setting the speed of the crosshead is different from the setting operation for setting the speed of the load or the strain, there is a problem that the setting workability is not good.

In order to solve such a problem, it is easily conceivable that the speed setting of the load and strain can be digitally set. The analog signals detected from the load cell 3 and the strain gauge 4 are also converted into digital signals. Therefore, when converting the detected analog signal into a digital signal, the control accuracy is limited to the resolution of the A / D converter.

For example, in the case of a metal material having high rigidity, the elongation in the elastic region is about 100 μm. In this test, if a resolution of about 1/2000 is required, a resolution of 0.05 μm can be obtained by simple calculation. is necessary. On the other hand, if the arithmetic part of the control is processed in analog, there is no problem of the resolution as described above, and the control can be performed very smoothly.

Therefore, in view of the above-mentioned conventional problems, the present invention adopts analog processing for controlling loads and strains, and enables digital processing to set those speeds. It is an object of the present invention to provide a control device for a material testing machine which improves control accuracy and operability.

[0012]

In order to achieve the above object, a display device of a material testing machine according to the present invention comprises a crosshead for loading a test piece as shown in the basic configuration diagram of FIG. Actuator 1 that moves up and down, encoder 2 that outputs a number of pulse trains corresponding to the rise and fall of the crosshead to be detected, first counting means 24 that counts pulse trains from encoder 2, load and elongation of test specimen to be detected Detecting means 3 and 4 for outputting analog signals in accordance with the above, first setting means 20b for setting a target elevating speed of the crosshead by an input operation, and second setting means for setting a target increase / decrease speed of the load or elongation by the input operation Setting means 20c, 20d and the first and second setting means 20a, 20c, 20
a pulse generator 22 for generating pulses at a speed corresponding to the speed set by d, a second counting means 23 for counting the pulses from the pulse generator 22, and a count value of the first counting means 24 A digital deviation calculating means 20e for calculating a deviation between the count value of the second counting means 23 and the second counting means 23;
Of the counting means 23 and the digital deviation calculating means 2
D / A conversion means 11 for D / A conversion of the deviation obtained at 0e, the count value of the second counting means 23 which has been D / A converted by the D / A conversion means 11, and the detection means 3 , 4
An analog deviation calculating means 14 for obtaining a deviation from an analog signal from the digital deviation calculating means 14, and an analog signal of the deviation obtained by the digital deviation calculating means 20e from the D / A converting means 11 or a deviation analog signal from the analog deviation calculating means 14. Selecting means SW11 for selecting one of the signals;
And a drive amplifier for outputting a drive signal for driving the actuator based on an analog signal of the deviation selected by W11 so as to cancel the deviation.

[0013]

In the above construction, the second counting means 23 corresponds to the target vertical movement speed of the crosshead set by the first setting means 20b and the target increase / decrease speed of the load or elongation set by the second setting means 20c. The pulse generated by the pulse generator 22 at the set speed is counted. Also, the second counting means 24
The number of pulse trains corresponding to the elevation of the crosshead from the encoder 2 is counted. The count value of the second counting means 23 and the first
The count value of the counting means 24 is calculated by the digital deviation calculating means 20e.
The digital deviation is converted into an analog signal by the D / A converter 11. The count value of the second count switch 23 is converted into an analog signal by the D / A converter 11 and then converted by the analog deviation calculator 14.
The deviation is taken. The selecting means SW11 selects one of the analog signal of the deviation obtained by the digital deviation calculating means 20e or the analog signal of the deviation from the analog deviation calculating means 14, and based on the selected analog signal of the deviation, the drive amplifier 12 A drive signal for driving the actuator 1 is output so as to cancel this deviation. Therefore, control of load, strain, and the like can be performed by analog processing, and their speed can be set by digital processing.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an embodiment of the control apparatus of the material testing machine according to the present invention. In FIG. 2, the same parts as those of the conventional apparatus described above with reference to FIG. I do.

In the illustrated embodiment, the operation panel 51 is constituted by a keyboard including ten keys and function keys. The operation panel 51 is used to create speed setting data of each test pattern, select a test pattern, and input a signal for instructing start / end of a test and the like, and an operation signal generated by key operation thereof Is input to the control unit 20 configured by a microcomputer (CPU).

The CPU constituting the control unit 20 executes a task determined by a control program stored in a program ROM (not shown), and performs key operations on an operation panel 51 performed by an operator while watching the display on the display unit 21. Creates / changes the setting data of the crosshead speed, load speed, and strain speed based on the input signal, and stores it in the RAM.
In the internal memory 20a. Internal memory 2
The speed setting data stored in 0a is composed of data designating the elevation of the crosshead and the increase or decrease of the load or strain and the speed data, and is selectively read out and output by selecting a test pattern by operating the keys on the operation panel 51. Is done.

The speed data of the read speed setting data is sent to the pulse generator 22 and is used to cause the pulse generator 22 to generate a pulse train at a speed corresponding to the target speed. The pulse signal generated by the pulse generator 22 is input to the clock input CK of the counter 23 which functions as the second counting means. The counter 23 receives an up signal and a down signal sent from the control unit 20 in accordance with the rising / falling and increasing / decreasing data, respectively, to an up input U and a down input D. Accordingly, the pulse signal from the pulse generator 22 is counted up and down.

The control unit 20 sends a switching control signal to the switches SW11 to SW13 in accordance with the selected test pattern.
The common contact c of the switches 11 to SW13 is switched to the contact 1, and in the case of the test pattern (b), the switches SW11 to SW13
Is switched to contact 2 or 3.

When the test pattern (a) is selected, the control unit 20 reads the count value of the counter 23, and reads the read count value.
The pulse signal generated by the encoder 2 is compared with a count (count) value read from a counter 24 serving as first counting means for counting up or counting down,
A digital deviation value that is a difference between the two count values is obtained. Thereby, the control unit 20 functions as a digital deviation calculating unit 20e. This deviation value is sent to the D / A converter 11 functioning as D / A conversion means via the contact 1 of the switch SW12, and is converted into an analog deviation signal. The analog deviation signal drives and controls the motor 1 via the switch S11 and the drive amplifier 12.

When the test pattern (b) is selected, the count value of the counter 23 is set to the value of the switch SW.
The signal is sent to the D / A converter 11 through the contacts 2 or 3 of 12 and is converted into an analog signal here. This analog signal is input as a target signal to a deviation calculator 14 acting as an analog deviation calculator, where the load is input from a load cell 3 as a detector through a load amplifier 13 and a contact 2 of a switch SW13 as a selector. This is compared with a detected signal or a detected strain signal input from the strain gauge 4 as a detecting means via the strain gauge amplifier 15 and the contact 3 of the switch SW13. Based on the result of this comparison, the analog deviation calculator 14 calculates the difference between the two signals and outputs a deviation signal. This deviation signal is supplied to the switch SW1
The drive of the motor 1 is controlled via the contact 2 or 3 and the drive amplifier 12.

With the above configuration, when setting the crosshead elevating speed in a test pattern (mode) in which a test piece is loaded while driving the crosshead at a constant speed,
When the mode is selected by the key operation of the operation panel 51 and the speed in this mode is input by the key operation of the operation panel 51, the control unit 20 operates the internal memory 20a.
The speed setting value of the crosshead is stored in. Thereby, the control unit 20 functions as the crosshead speed setting unit 20b.

The operation panel 51 is also used to set the load increase / decrease rate in a test pattern (mode) in which the load rate or the strain rate of the test piece is kept constant and the test piece is loaded.
When the speed in this mode is input by operating the key on the operation panel 51, the control unit 20 causes the pulse generator 22 to generate a pulse corresponding to the speed input by operating the key. Data for determining the speed is created and stored in the internal memory 20a.
To memorize. Thereby, the control unit 20 functions as the load speed setting unit 20c or the strain speed setting unit 20d.

After setting each mode and its speed as described above, when a test start is instructed by operating the keys on the operation panel 51, the switch SW is set in accordance with the control mode.
11 to set the state of SW13 and the internal memory 2
The data stored in 0a is read out and output to the pulse generator 22. As a result, the pulse generator 22 generates a pulse having such a speed as to move the crosshead up and down or increase or decrease the load at the set speed.

When the test starts, the control unit 20 reads the count value of the counter 23. When the control mode is the speed control of the crosshead, the count value of the counter 24 is also read, a deviation between the two count values is obtained, and a digital deviation signal is output to the D / A converter 11. After this digital deviation signal is converted into an analog deviation signal, it is used to drive and control the motor 1 via the switch SW11 and the drive amplifier 12. On the other hand, in the case of load or strain speed control, the count value of the counter 23 is output to the D / A converter 11 as it is, and is converted into an analog signal. The deviation from the signal from the total 4 is taken. The resulting analog deviation signal is the switch S
It is used for controlling the drive of the motor 1 via W11 and the drive amplifier 12.

The details of the operation of the device outlined above are described in C
The work performed by the PU 6 according to the control program stored in the ROM (not shown) will be described below with reference to the flowcharts of FIGS.

The CPU 6 executes a main routine shown in FIG. For example, the operation is started when the power is turned on, initialization is performed in the first step S1, and a control mode and a speed setting process for setting a speed in each mode are performed in a subsequent step S2. After that, in step S3, when starting the control, a control start process is performed, and then the process proceeds to step S4, where a control process for performing a test in the mode designated here is performed. Then, the process proceeds to the next step S5, performs other processing, returns to the step S2, and repeats the steps S2 to S5.

In the control mode and speed setting processing in step S2, as shown in FIG. 4, first, in step S21, it is determined whether or not there is a mode selection input by operating a key on the operation panel 51.
If the determination is NO, step S3 of the main routine
Proceed to. If the determination in step S21 is YES, the process proceeds to step S22 to wait for speed setting by key operation of the operation panel 51 for the selected mode. Thereafter, the process proceeds to step S23, and the set value set by the operation of step S22 is stored in the internal memory 20a. Then, the process proceeds to step S24, where the internal memory 2 is operated by key operation.
It is determined whether there is an operation input for reading the set value stored in 0a. Step S2 when there is no operation input
Proceed to 5 to wait for an input operation for changing the speed. If there is an input operation in step S25, step S2
6, the data for the pulse generator 22 is created based on the input and stored in the internal memory 20a, and then the process proceeds to step S3 of the main routine.

On the other hand, when there is an operation input for reading the set value stored in the internal memory 20a, the process proceeds to step S27, and based on the input, the set value is read from the internal memory 20a, and then the process proceeds to step S26. In step S26, data for the pulse generator 22 is created based on the set values read in step S27, stored in the internal memory 20a, and then the operation proceeds to step S3 of the main routine.

In the control start process in step S3, as shown in FIG. 5, first, in step S31, it is determined whether or not there is a control start input by a key operation on the operation panel 51, and the determination in step S31 is NO. In this case, the process immediately proceeds to step S4 of the main routine.
If the determination in step S31 is YES, step S3
Proceeding to 2, the control mode data is read from the internal memory 20a. Thereafter, the process proceeds to step S33, and step S2
3 according to the data read out from the switches SW1 to SW1.
The state of SW3 is set and a state for performing a test in the control mode is formed. Further thereafter, step S34
In step S26, the data for the pulse generator 22 stored in the internal memory 20a is read out in step S26, and the read data is output to the pulse generator 22 in step S35. Proceed to.

In the control processing of step S4,
As shown in FIG. 6, first, in step S41, the count value of the counter 22 is read. In a succeeding step S42, it is determined whether or not the control mode is the crosshead speed mode, and if this determination is YES, a step S4
Proceeding to 3, the count value of the counter 24 is read. Thereafter, the process proceeds to step S44, where a deviation between the count value of the counter 22 and the count value of the counter 24 is calculated.
The deviation value obtained in this step S44 is output to the D / A converter 11 in the following step S45, and then the process proceeds to step S5 of the main routine. On the other hand, if the determination in step S42 is NO, the process proceeds to step S45, in which the count value of the counter 22 is directly output to the D / A converter 11, and then the process proceeds to step S5 of the main routine.

[0031]

As described above, according to the present invention, the control of load and strain is performed by analog processing.
In addition, since these speed settings can be performed by digital processing, the respective advantages can be utilized, and control accuracy and operability can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a control device of a material testing machine according to the present invention.

FIG. 2 is a diagram showing one embodiment of a control device of the material testing machine according to the present invention.

FIG. 3 is a main flowchart of work performed by a CPU in FIG. 2;

FIG. 4 is a flowchart showing details of a part of the flowchart of FIG. 3;

FIG. 5 is a flowchart showing details of another part of the flowchart in FIG. 3;

FIG. 6 is a flowchart showing details of still another part of the flowchart of FIG. 3;

FIG. 7 is a diagram showing an example of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Motor (actuator) 2 Encoder 3 Rosecell (detection means) 4 Strain gauge (detection means) 11 D / A converter (D / A conversion means) 12 Drive amplifier 14 Deviation calculator (analog deviation calculation means) 20b Crosshead speed setting Means (first setting means) 20c Load speed setting means (second setting means) 20d Strain speed setting means (second setting means) 20e Deviation calculating means (analog deviation calculating means) 22 pulse generator 23 counter (first 1 counting means) 24 counter (second counting means) SW11 switch (selection means)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-118236 (JP, A) JP-A-1-167634 (JP, A) JP-A 2-77656 (JP, U) JP-A 63-118236 145149 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 3/08 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. An actuator for raising and lowering a crosshead for loading a test piece, an encoder for outputting a pulse train of a number corresponding to the lifting and lowering of the crosshead to be detected, and a first counting device for counting a pulse train from the encoder Means, detecting means for outputting an analog signal corresponding to the load or elongation of the test piece to be detected, first setting means for setting a target lifting / lowering speed of the crosshead by input operation, and target of load or elongation by input operation Second setting means for setting the increasing / decreasing speed; a pulse generator for generating a pulse at a speed corresponding to the speed set by the first and second setting means; and counting the pulses from the pulse generator Second counting means; digital deviation calculating means for calculating a deviation between the count value of the first counting means and the count value of the second counting means; and the second counting means D / A conversion means for D / A converting the count value and the deviation obtained by the digital deviation calculation means; and the count value of the second counting means D / A converted by the D / A conversion means. Analog deviation calculating means for calculating a deviation from the analog signal from the detecting means; analog signal of the deviation obtained by the digital deviation calculating means from the D / A converting means or deviation analog signal from the analog deviation calculating means And a drive amplifier that outputs a drive signal for driving the actuator based on an analog signal of the deviation selected by the selection unit so as to cancel the deviation. Control device for material testing machine.