JPH1183714A - Material tester driven with plurality of actuators - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material tester wherein plurality of actuators are driven in synchronous manner. SOLUTION: A load pressure plate 7 is pressed and moved by four load hydraulic cylinders 4a-4d to compress a test piece W. A control hydraulic cylinder 3 is load-feedback-controlled by a deviation between an actual load on the test piece W and a target load, further, the load hydraulic cylinders 4a-4d are feedback-controlled so that a relative displacement amount between the control hydraulic cylinder 3 and the load hydraulic cylinders 4a-4d is pre-set reference value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of loading a specimen by driving a plurality of actuators in synchronization with each other, such as a biaxial loading test used for evaluating the performance of seismic isolation rubber or the like. To a material testing machine.

[0002]

2. Description of the Related Art Conventionally, there has been known a biaxial loading tester for measuring a shear deformation of a seismic isolation rubber as shown in FIG. As shown in FIG. 5, the biaxial loading tester has a base 52 and a cross yoke 53 whose both ends in the direction perpendicular to the paper are fixed to a support frame (not shown). For example, four hydraulic cylinders 54 are provided, and a load yoke 56 is connected to a ram rod of the hydraulic cylinder 54 via a ball seat (not shown). The left and right ends (both ends in the vertical direction of the paper) of the load yoke 56 are supported by a support frame (not shown) via a vertical slide guide. An upper platen 59 is provided on the lower surface of the load yoke 56 via a slide bearing 58 so as to be movable in the horizontal direction. An upper platen 60 is provided on a lower surface of the upper platen 59. Base 5
2 has a lower platen 6 through a horizontal slide bearing 61.
2 is provided, and a lower surface plate 63 is provided on the upper surface of the lower platen 62. The specimen 51 made of seismic isolation rubber is fixed to the upper and lower panels 60 and 63 with bolts and nuts. The upper and lower platens 59 and 62 are moved by the horizontal slide bearings 58 and 61 in the horizontal direction of FIG.

The upper and lower platens 59 and 62 are provided with brackets 64 and 65, respectively.
4, 65 are connected to both ends of a horizontal load hydraulic cylinder 66.
The distance between 4, 65 changes.

Then, the upper platen 59 is pushed vertically by the load yoke 56 to apply a compressive load to the specimen 51. In this state, the hydraulic cylinder 66 is expanded and contracted to move the upper and lower platens 59 and 62 horizontally. Reciprocate relatively. At this time, the displacement amount of the hydraulic cylinder 66 is measured by a displacement meter, and the load load is measured by a load cell provided on the load yoke 56, and the energy curve in which the horizontal axis represents the horizontal movement amount and the vertical axis represents the load cell output. Draw and evaluate the energy loss due to the shear deformation of the specimen 51 from the area of the energy curve.

At this time, each of the vertical load hydraulic cylinders 54 is controlled by load feedback so that the actual load becomes the target load or by displacement feedback such that the actual shaft displacement becomes the target displacement. . Here, since each hydraulic cylinder 54 equally divides the compressive load applied to the specimen 51, the target load of each hydraulic cylinder 54 is １ ／ or 1 of the compressive load according to the number of hydraulic cylinders 54.
/ 4.

[0006]

As described above, when the load feedback control of the hydraulic cylinder is performed, the load generated by the plurality of compression hydraulic cylinders is controlled to a target value, but the displacement varies, so that the horizontal displacement is varied. When the diameter becomes large, the upper platen may be greatly inclined. On the other hand, when performing displacement feedback control, the displacement of each hydraulic cylinder may deviate from the actual target value due to a manufacturing error or an assembly error of a plurality of compression hydraulic cylinders, and the intended operation may not be performed. As a result, an unbalanced load acts on the upper platen, and the upper platen or other mechanisms may be deformed.

An object of the present invention is to provide a material testing machine in which a plurality of actuators are driven synchronously.

[0008]

[Means for Solving the Problems]

(1) Referring to FIG. 1 to FIG. 3 showing an embodiment, the invention of claim 1 comprises a plurality of load actuators 4 a to 4 d for loading a specimen W, and a load actuator 4.
control actuator 3 for controlling the driving of a to 4d
And a detector 1 for detecting the load or displacement acting on the specimen W
2, 6a to 6d, a first feedback control circuit 20 that drives and controls the control actuator 3 by displacement feedback control or load feedback control based on the displacement or load detected by the detector, The load actuator 4 is controlled so that the relative displacement with the actuators 4a to 4 becomes a predetermined reference value.
The above object is achieved by providing the second feedback control circuit 30 that performs feedback control of the signals a to 4. (2) Referring to FIGS. 1, 2 and 4 showing an embodiment, the invention according to claim 2 comprises at least first and second actuators 4a 'and 4b for loading a specimen W;
Detector 6a to detect the load or displacement acting on the specimen W
6d, 12 ', a first feedback control circuit 20' for driving and controlling the first actuator 4a 'by displacement feedback control or load feedback control based on the load or displacement detected by the detector,
And a second feedback control circuit 30 that performs feedback control of the second actuator 4b so that the relative displacement between the second actuator 4a ′ and the second actuator 4b becomes a predetermined reference value. To achieve.

In the meantime, in the section of the means for solving the above-mentioned problem which explains the constitution of the present invention, the drawings of the embodiments of the present invention are used in order to make the present invention easy to understand. However, the present invention is not limited to this.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 are schematic diagrams showing a configuration of a material testing machine according to the present embodiment.

As shown in FIGS. 1 and 2, a material testing machine according to the present embodiment comprises a single control hydraulic cylinder 3 which is suspended at the center of an upper cross yoke 2 of a frame 1. Similarly, four return-type load hydraulic cylinders 4a to 4d provided around the control hydraulic cylinder 3 of the upper crosshead 2 are provided. Ball seats 5a to 5d are provided at the tips of the piston rods of the four load hydraulic cylinders 4a to 4d.
(5c and 5d are not shown) and load cells 6a to 6d (6c
And 6d are not shown), the load platen 7 is attached via
The specimen W is mounted between the load platen 7 and the lower platen 8. A flat plate 9 is horizontally attached to the tip of the piston rod of the control hydraulic cylinder 3 with a pin, and the flat plate 9 is attached to the tip of the piston rod of the load hydraulic cylinders 4a to 4d with a pin.
0a to 10d are mounted horizontally. Micro displacement meters (for example, differential transformers) 11a to 11d are interposed between the flat plate 9 and the flat plates 10a to 10d, respectively.

FIG. 3 shows a control circuit of the material testing machine according to the present embodiment. Although FIG. 3 shows the control hydraulic cylinder 3 and the load hydraulic cylinders 4a and 4b for simplicity, the same applies to the load hydraulic cylinders 4c and 4d.

In FIG. 3, a displacement meter 12 detects a displacement of a piston rod of the control hydraulic cylinder 3 and outputs a displacement feedback signal FS. The displacement detected by the displacement meter 12 represents the displacement of the specimen W. The displacement of the specimen W may be directly detected and replaced with the signal of the displacement meter 12. Displacement signal F
S is amplified by the displacement amplifier 21. Load cells 6a, 6
b detects the load generated by the load hydraulic cylinders 4a and 4b, and outputs load signals La and Lb. The load generated by the load hydraulic cylinders 4c, 4d is similarly detected by load cells 6c, 6d (not shown), and the load cells 6c, 6d
d outputs load signals Lc and Ld. Load signals La to L
d is input to the adder 22 and added, and the adder 22 outputs the load feedback signal FL. The setting signal output unit 23 outputs a target displacement signal during displacement feedback control or a target load signal during load feedback control. These target signals can be arbitrarily set by the operator according to the test conditions. The switch 24 selects one of the displacement feedback signal FS and the load feedback signal FL, and the contacts a and b are switched by an operator. The deviation between the target load signal and the load feedback signal FL or the deviation between the target displacement signal and the displacement feedback signal FS is calculated by the deviation unit 25, and the deviation signal is amplified by the servo amplifier 26 and supplied to the servo valve 3V of the control hydraulic cylinder 3. Is done. The above feedback control circuit 20 is a first feedback circuit for control.

Pressure oil is supplied to the servo valve 3V from a control hydraulic circuit (not shown), and the pressure oil is controlled by the servo valve 3V according to the deviation signal, whereby the control hydraulic cylinder 3 is operated.

On the other hand, the minute displacement feedback signals S1 and S2 output from the minute displacement meters 11a and 11b are amplified by the displacement amplifiers 31a and 31b, and are amplified by the deviation devices 32a and 32b.
Is input to The reference displacement signals are also input from the reference displacement signal output devices 33a and 33b to the deviation devices 32a and 32b, and the deviation devices 32a and 32b calculate the deviation between the minute displacement feedback signal and the reference displacement signal. The calculated deviation signal is amplified by the servo amplifiers 34a and 34b and output to the servo valves 4aV and 4bV of the load hydraulic cylinders 4a and 4b.
The same applies to the load hydraulic cylinders 4c and 4d. The above-described feedback control circuits 30a and 30b are the second feedback circuits for the load.

The servo valves 4aV to 4dV (4cV, 4dV
(Not shown) is supplied with pressure oil from a load hydraulic circuit (not shown), and the servo valves 4aV to 4d
The pressure oil is controlled by V, whereby the load hydraulic cylinders 4a to 4d are operated.

The operation of this embodiment will be described with respect to displacement feedback control. In the following description, when the load platen 7 is moved horizontally, the load hydraulic cylinders 4a,
The operation of the load hydraulic cylinder 4c,
4d operates similarly, and will be described as needed.

Prior to the test, the reference signal output devices 33a, 33a
The output signal of 33b is set to zero displacement. Micro displacement meter 1
The position of the flat plate 9 is finely adjusted by adjusting the stroke of the control hydraulic cylinder 3 so that the outputs of 1a and 11b become zero. This adjustment is performed on a minute displacement meter 11 on a monitor screen (not shown).
It is possible to display the output values of a to 11d, and manually operate the servo valve 3V while visually observing the output values. Further, the switch 24 is switched to the contact a side.

When the test is started, a target displacement signal is output from the setting signal output device 23, and a zero displacement signal is output from the reference signal output devices 33a and 33b as a reference displacement signal. The displacement feedback signal FS is sent to the deviation device 25 via the switch 24.
Is input, the deviation between the displacement feedback signal FS and the target displacement is calculated by the deviation device 25, and the servo valve 3V
Drives the control hydraulic cylinder 3 so that the deviation between them becomes zero.

The control hydraulic cylinder 3 operates according to the target displacement signal, and accordingly, the flat plate 9 moves up and down. When the flat plate 9 moves, the minute displacement meters 11a, 11
The displacement signals S1 and S2 corresponding to the amount of movement of the flat plate 9 are output from b, and deviations from the zero displacement signal are calculated by the deviation units 32a and 32b. As described above, the minute displacement meters 11a, 1
Since the initial output signal of 1b is adjusted to zero, the deviation signals output from the deviation units 32a and 32b are signals corresponding to the amount of movement of the flat plate 9. The deviation signal is the servo amplifier 3
The servo signals 4aV and 4bV are amplified by the gains predetermined in advance to the servo valves 4a and 34b. Similarly, the servo valves 4cV and 4dV are also driven. As a result, the load hydraulic cylinders 4a to 4d
And the specimen W is loaded by the displacement feedback control in accordance with the target displacement output from the setting signal output unit 23.

Next, the operation of the present embodiment will be described with respect to load feedback control. Prior to the test, the output signals of the reference signal setting and outputting devices 33a and 33b are set to zero displacement. The stroke of the control hydraulic cylinder 3 is manually adjusted as described above so that the outputs of the minute displacement meters 11a and 11b become zero. The switch 24 is switched to the contact b side.

When the test is started, a target load signal is output from the setting signal output device 23, and a zero displacement signal is output from the reference signal output devices 33a and 33b as a reference displacement signal. The adder 22 adds the load signals La to Ld to calculate the total load applied to the specimen W.
5, the load feedback signal FL is input. The deviation between the load feedback signal FL and the target load is calculated by the deviation device 25, and the servo valve 3V drives the control hydraulic cylinder 3 so that the deviation between the two becomes zero.

As described above, the control hydraulic cylinder 3 operates according to the target load signal, and accordingly, the flat plate 9 moves up and down. When the flat plate 9 moves, the minute displacement meter 1
Displacement signals corresponding to the amount of movement of the flat plate 9 are output from 1a and 11b, and deviations from the reference displacement signal are calculated by the deviation units 32a and 32b. As described above, the minute displacement meters 11a, 1
Since the initial output signal of 1b is adjusted to zero, the deviation signals output from the deviation units 32a and 32b are signals corresponding to the amount of movement of the flat plate 9. The deviation signal is the servo amplifier 3
The servo signals 4aV and 4bV are amplified by the gains predetermined in advance to the servo valves 4a and 34b. Similarly, the servo valves 4cV and 4dV are also driven. As a result, the load hydraulic cylinders 4a to 4d
The specimen W is loaded by the load feedback control in accordance with the target load output from the setting signal output device 23.

As described above, since the four load hydraulic cylinders 4a to 4d are driven in synchronization with the movement of the control hydraulic cylinder 3, there is a manufacturing error in the hydraulic cylinders 4a to 4d or the feedback circuits 30a, 30b , The load hydraulic cylinders 4a to 4d can move at the same speed as the control hydraulic cylinder 3, respectively. Incidentally, each load hydraulic cylinder 4a-4d
Are driven by independent displacement feedback circuits, the load hydraulic cylinders 4a to 4
A different motion occurs in the motion of d. In the case of the above-described load feedback control, since the output signals of the respective reference signal output devices 33a to 33d (33c and 33d are not shown) are unified to zero signals, the flat plate 9 is kept horizontal. The load hydraulic cylinders 4a to 4d have the same operation amount even during the load feedback control, and the load platen 7 does not tilt.

In the above description, the control hydraulic cylinder 3 is provided separately from the load hydraulic cylinders 4a to 4d. However, the control hydraulic cylinder 3 is omitted and the load hydraulic cylinders 4a to 4d are provided.
Any one of the hydraulic cylinders may be used as a master cylinder.

FIG. 4 shows a control circuit of such a material testing machine. The same parts as those in FIG. 3 are denoted by the same reference numerals, and only the differences will be described. The load hydraulic cylinder 4a 'is provided with a displacement meter 12' for detecting the stroke, and its output signal is amplified by a displacement amplifier 21 '. When the switch 24 is switched to the contact point a, the displacement of the load hydraulic cylinder 4a 'input to the deviation device 25, that is, the deviation between the actual displacement of the specimen W and the target displacement is calculated by the deviation device 25, and the deviation signal is calculated. Is input to the servo valve 4aV 'of the load hydraulic cylinder 4a', whereby the load hydraulic cylinder 4a 'is operated. When the load hydraulic cylinder 4a 'is displaced, the flat plate 9 moves and an output signal is output from the minute displacement meter 11b. Deflector 32b
Calculates a deviation between the deviation signal and a reference displacement signal (for example, a zero displacement signal) output from the reference signal output unit 33b. The calculated deviation signal is amplified by the servo valve 34b and input to the servo valve 4bV, whereby the servo valve 4bV is driven. Reference numeral 20 'denotes a first feedback control circuit.

Although the hydraulic cylinder 3 is used as the control actuator, an electric motor and a screw rod may be used. Although the zero displacement signals are output from the reference signal output devices 33a to 33d, when the test is performed with the load platen 7 inclined, a displacement signal corresponding to the inclination of the load platen 7 is output. Reference signal output devices 33a to 33
d may be set. Furthermore, a material testing machine using four load hydraulic cylinders 4a to 4d has been described.
The present invention can be applied not only to the hydraulic cylinder but also to a material testing machine using an electric motor. Furthermore, although the compression tester has been described above, the present invention can also be applied to a tensile tester and a bending tester, and of course, to a biaxial loading tester as shown in FIG.

[0028]

As described above, according to the first aspect of the present invention, since a plurality of load actuators are driven in synchronization with the movement of the control actuator, even if there is a manufacturing error or the like in each of the load actuators. Each of the load actuators is driven on the basis of the control actuator, so that variations in operation due to manufacturing errors and the like can be suppressed. In particular, when the compression test is performed by the load feedback control, if the test is started by holding the platen horizontally by the load actuator in advance, the test can be performed while the platen is horizontally held even by the load feedback control. According to the second aspect of the invention, since the second actuator is operated based on the movement of the first actuator, the same operation and effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a configuration of a material testing machine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a block diagram showing a control circuit according to the embodiment of the present invention.

FIG. 4 is a block diagram showing a control circuit according to another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a two-axis loading tester for explaining a conventional problem.

[Explanation of symbols]

 3, 4a 'Control hydraulic cylinder 3V, 4aV, 4bV Servo valve 4a-4d Load hydraulic cylinder 6a-6d Load cell 7 Load platen 9,10a-10d Flat plate 11a-11d Micro displacement meter 12,12' Displacement meter 20 Control feedback circuit 20 '' Feedback circuit 23 Setting signal output device 24 Switching device 30 Load feedback circuit 33a, 33b Reference signal output device W Specimen

Claims (2)

[Claims] 1. A plurality of load actuators for loading a specimen, a control actuator for controlling driving of the load actuator, a detector for detecting a load or displacement acting on the specimen, and a detector for detecting the load or displacement. A first feedback control circuit that drives and controls the control actuator by displacement feedback control or load feedback control based on the displacement or load that has been applied, and a reference value in which the relative displacement between the control actuator and the load actuator is predetermined. And a second feedback control circuit that performs feedback control of the load actuator so as to provide a material testing machine driven by a plurality of actuators. 2. At least first and second actuators for loading a specimen, a detector for detecting a load or a displacement applied to the specimen, and a detector for detecting a load or a displacement detected by the detector. A first feedback control circuit that drives and controls the first actuator by displacement feedback control or load feedback control, and a relative displacement amount between the first actuator and the second actuator becomes a predetermined reference value. And a second feedback control circuit for performing feedback control of the second actuator. A material testing machine driven by a plurality of actuators.