JP2006266347A - Hydraulic actuator control method and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic actuator control method and its device for, for example, preventing reduction of pushing speed of a rod of a hydraulic actuator and increasing response property of the hydraulic actuator for a control signal because working liquid discharged from a pulling side chamber is returned into a pushing side chamber by a boost circuit in a pushing load process for feeding working liquid into the pushing side chamber from a discharge amount variable pump. <P>SOLUTION: Direction switching valves 2, 3 communicating with the pushing side chamber S in the hydraulic actuator 1 and a direction switching valve communicating with the pulling side chamber L are provided, a liquid supply pipe passage 4 connected with a liquid pressure generating source and a return liquid pipe passage 5 connected with a tank are connected with each direction switching valve, the discharge amount variable pump 7 is arranged in the liquid supply pipe passage, and a high speed on-off valve 8 is arranged in the liquid supply pipe passage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to, for example, a hydraulic actuator control method and apparatus used for load control on a specimen in a material loading tester for a structural member for civil engineering construction, cylinder load control of a hydraulic press machine and cylinder displacement control.

As this type of conventional hydraulic actuator control device, for example, as shown in FIG. 6, as a hydraulic actuator K incorporated in the loading tester, attached to the attachment member D on the rod K ₁ on one side rod type hydraulic cylinder A directional control valve M comprising a two-position electromagnetic directional switching valve that communicates with the push side chamber S and the pull side chamber L in the hydraulic actuator K is provided. A liquid supply line N connected to the pressure source and a return liquid line G connected to the tank T are connected, and a discharge amount variable pump P composed of an inverter-driven motor is disposed in the liquid supply line N. A high-speed on / off valve E comprising a 2-port 2-position spring return electromagnetic high-speed switching valve is disposed between the liquid supply line N and the tank T, and a potentiometer or the like for taking out the displacement of the rod K ₁ is provided. A position sensor F, a load sensor H such as a load cell for measuring the load, a control pressure sensor J as a pressure transducer for detecting the pressure in the liquid supply pipe N, and an operation control unit Q for calculating and controlling these main control elements. The structure of the structure is known.

Accordingly, as shown in FIG. 7, the pushing process in the right direction in the figure and the unloading process of the pushing load with respect to the controlled object W, and the pulling process and the pulling load in the left direction in the figure with respect to the controlled object W are removed. In the loading process, while obtaining the actual value as a feedback signal from the load sensor H, the position sensor F, and the control pressure sensor J, the load by the hydraulic actuator K, the displacement of the rod K ₁ , and the pressure in the liquid supply line N, respectively, The arithmetic control unit Q outputs a control signal so as to match a predetermined target value for control such as a predetermined load or rod displacement, and feedback-controls the operating state of the hydraulic actuator.

That is, in the process of pushing load on the control object W, in FIG. 6, the liquid supply line N is connected to the push side chamber S of the hydraulic actuator K via the direction switching valve M, and the pull side chamber S is connected to the tank T. In this state, hydraulic fluid as hydraulic fluid is supplied from the discharge amount variable pump P to the push chamber S of the hydraulic actuator K, and this control pressure is driven by an inverter motor by comparing the target value with the actual value as a feedback signal. When the actual value reaches the target value, the process shifts to a pushing load removal process. In this pushing load removal process, the high-speed on / off valve E is turned on / off at high speed, This on / off control is controlled by comparing the target value with the actual value, which is the feedback signal. Finally, the pushing load reaches zero, and the process moves to the pulling load process. In the pulling load process, the direction switching valve M is switched in the off state of the high-speed on / off valve E, the pulling chamber L is connected to the liquid supply line N, the push chamber S is connected to the tank T, and the hydraulic actuator K is pulled. The working fluid is supplied to the side chamber L from the liquid supply line N, and the control pressure is the same as in the pushing load process, and the discharge amount variable pump P driven by the inverter motor by comparing the target value with the actual value as the feedback signal. When the actual value reaches the target value, the process shifts to the removal process of the pulling load, and in this pulling load removal process, the high-speed on / off valve E is controlled at high speed on / off. It is controlled by comparison with the actual value, which is a feedback signal. Finally, the pulling load reaches zero, and if necessary, the process proceeds to the pushing load process again. Loading Test of a controlled object W specimen is performed by controlling the operating state of Ta.
Japanese Patent Publication No. 5-9641

However, in the case of this conventional structure, a hydraulic actuator K is single rod type cylinder, inevitably push side pressure receiving areas serving head side from a larger pressure receiving area than the pull side pressure receiving area serving rod side, of the rod K ₁ The pushing speed is lower than the pulling speed to the left in the figure. As a result, the response of the hydraulic actuator K to the control signal is lowered, and the control reliability and stability may be lacking. is doing.

  The present invention aims to solve these disadvantages. Among the present inventions, the invention of the method according to claim 1 includes a directional control valve and a pull side chamber communicating with a push side chamber in a hydraulic actuator. A directional switching valve that communicates is provided, a supply liquid line connected to a hydraulic pressure source and a return liquid line connected to a tank are connected to each directional switching valve, and a discharge amount variable pump is connected to the liquid supply line And a high-speed on / off valve in the liquid supply pipe line, comparing the target value such as load and displacement with the actual value, and operating condition of the hydraulic actuator by the variable discharge pump and high-speed on / off valve In the push-load process in which the working liquid is fed from the discharge amount variable pump into the push side chamber, the working liquid discharged from the pull side chamber is returned to the push side chamber by a boost circuit. Hydraulic actuator In the control method.

  According to a second aspect of the present invention, the working liquid discharged from the pulling side chamber is returned to the tank in the pushing load process of feeding the working liquid from the discharge amount variable pump into the pushing side chamber. The method invention described in claim 3 is characterized in that the variable discharge pump is driven by a servo motor, and the method invention described in claim 4 The hydraulic actuator is a one-side rod type cylinder having a pressure-side pressure receiving area: pull-side pressure receiving area = 2: 1.

  According to a fifth aspect of the present invention, there is provided a direction switching valve that communicates with the push-side chamber and a direction switching valve that communicates with the pull-side chamber in the hydraulic actuator, and each direction switching valve is connected to a hydraulic pressure generating source. A liquid supply line and a return liquid line connected to the tank, a variable discharge pump is provided in the liquid supply line, and a high-speed on / off valve is provided in the liquid supply line to allow load and displacement. Comparing the target value and the actual value, etc., with an operation control unit for calculating and controlling the operation state of the hydraulic actuator by the variable discharge pump and the high-speed on / off valve, at least the hydraulic actuator, each of the above In the hydraulic actuator control device, the direction switching valve, the discharge amount variable pump, the tank, and the high-speed on / off valve are integrally mounted.

  According to a sixth aspect of the present invention, there is provided a direction switching valve communicating with the push-side chamber and a direction switching valve communicating with the pull-side chamber in the hydraulic actuator, and each direction switching valve is connected to a hydraulic pressure generating source. A liquid supply line and a return liquid line connected to the tank, a variable discharge pump is provided in the liquid supply line, and a high-speed on / off valve is provided in the liquid supply line to allow load and displacement. And a control unit for calculating and controlling the operating state of the hydraulic actuator by the variable discharge pump and the high-speed on / off valve while comparing the target value and the actual value such as the discharge value variable pump in the push side chamber The hydraulic actuator control device is provided with a boost circuit for returning the working liquid discharged from the pulling side chamber to the pushing side chamber in a pushing load process of feeding the working liquid from the pulling side chamber.

  According to a seventh aspect of the present invention, the variable discharge pump is driven by a servo motor, and the hydraulic actuator has a pressure-side pressure receiving area: a pressure-side pressure receiving area = It is a 2: 1 single rod type cylinder.

  As described above, in the invention according to claim 1 or 6, the present invention boosts the working liquid discharged from the pulling side chamber in the pushing load process of feeding the working liquid from the discharge amount variable pump into the pushing side chamber. Since the circuit is returned to the push-side chamber, for example, it is possible to prevent a decrease in the pushing speed of the rod of the hydraulic actuator, to improve the response of the hydraulic actuator to the control signal, and to improve the control reliability and Stability can be improved.

  According to a second aspect of the present invention, in the pushing load process in which the working liquid is fed from the discharge amount variable pump into the push side chamber, the operation is discharged from the pull side chamber without selecting the boost circuit. Since the liquid is returned to the tank, for example, there is a decrease in the pushing speed of the rod of the hydraulic actuator, but a high output of the pressure receiving pressure area x the working liquid pressure will be exhibited, and the boost circuit It is possible to select whether to use or not, and to increase the flexibility of control.

  Further, in the invention according to claim 3 or 7, since the variable discharge pump is driven by a servo motor, control flexibility is provided by a high output torque characteristic at a high rotation speed and a low speed as compared with an inverter motor drive. In addition, in the invention according to claim 4 or 8, the hydraulic actuator includes a one-side rod type cylinder having a pressure-side pressure receiving area: pull-side pressure receiving area = 2: 1. Therefore, it can be equivalent to a double rod type cylinder, and the ease and stability of control can be improved.

  In the invention according to claim 5, since at least the hydraulic actuator, the directional switching valves, the variable discharge pump, the tank, and the high-speed on / off valve are integrally mounted, each device The length of the pipe line can be shortened, the delay due to the compressibility of the working liquid in the pipe line can be suppressed, the heat generation and power loss can be suppressed, and the control response and reliability can be improved. be able to.

  1 to 5 show an embodiment of the present invention. Reference numeral 1 denotes a hydraulic actuator 1, which uses a one-side rod type hydraulic cylinder, and a control object attached to an attachment member D on the rod 1a. A directional switching valve 2 composed of a two-position electromagnetic directional switching valve that communicates with the push-side chamber S in the hydraulic actuator 1 and a directional switching valve 3 of the same structure that communicates with the pull-side chamber L are provided. A liquid supply line 4 connected to the hydraulic pressure source and a return liquid line 5 connected to the tank T are connected to the directional switching valves 2 and 3, and the liquid supply line 4 is driven by a servo motor 6. A variable discharge pump 7 is disposed, a high-speed on / off valve 8 comprising a 2-port 2-position spring return electromagnetic high-speed switching valve is disposed between the liquid supply line 4 and the tank T, and the displacement of the rod 1a Take out the potentiometer A position sensor 9, a load sensor 10 such as a load cell for measuring a load, a control pressure sensor 11 as a pressure transducer for detecting pressure in the liquid supply pipe 4, and an arithmetic control unit 12 for calculating and controlling these main control elements. It is provided and configured.

In this case, the hydraulic actuator 1 uses a push-side pressure area A ₁ : pull-side pressure-receiving area A ₂ = 2: 1 single-side rod type cylinder, and by using the boost circuit 13, the push-side chamber S and the pull-side chamber are used. The same oil pressure will be applied to L, and the pressure generated by pressing = (A ₁ -A ₂ ) x oil pressure = (2-1) x A ₂ x oil pressure = A ₂ x oil pressure. Is equivalent to

  Reference numeral 13 denotes a boost circuit. In this case, as shown in FIG. 3, the P ports of the directional control valves 2 and 3 are connected to the liquid supply pipe 4 and returned to the T ports of the directional control valves 2 and 3. A liquid line 5 is connected, and both the push-side chamber S and the pull-side chamber L of one direction switching valve 2 are connected to the liquid supply line 4 and are operated from the discharge amount variable pump 7 in the push-side chamber S. In the push load process for feeding the liquid, a generated load difference is generated from the area difference between the push side chamber S and the pull side chamber L, and the working liquid discharged from the pull side chamber L is returned to the push side chamber S.

  Since this embodiment has the above-described configuration, the boost circuit 13 is used in consideration of the load on the controlled object W, the predicted fracture load of the specimen, and the influence on the hydraulic actuator 1 due to the fracture of the specimen. If it is selected to do so, at the start of the pushing load process on the controlled object W, as shown in FIG. 3, each of the switching valves 2 and 3 is set to a non-excitation position, and each direction switching valve 2 is connected to the liquid supply line 4. Each P port of 3 is connected, a return liquid pipe 5 is connected to each T port of each direction switching valve 2. 3, and both the push side chamber S and the pull side chamber L of one direction switching valve 2 are connected to each other. A boost circuit 13 connected to the liquid supply line 4 is configured. When the high-speed on / off valve 8 is in an off state, the booster circuit 13 is operated from the liquid supply line 4 via the direction switching valve 2 to the push-side chamber S of the hydraulic actuator 1. Supply oily working liquid and boost circuit 13 The working fluid as the working oil is also supplied to the side chamber L from the liquid supply line 4 via the direction switching valve 3, and the push-side pressure receiving area is larger than the pull-side pressure receiving area. As a result, the rod 1a moves to the right, which is the pushing direction, and the working liquid discharged from the pulling side chamber L is returned to the pushing side chamber S. This control pressure is a target value and an actual value as a feedback signal. The comparison is controlled by a variable discharge amount pump 7 driven by a servo motor.

  Then, when the actual value reaches the target value, the process proceeds to the pushing load removing process, and in this pushing load removing process, the high-speed on / off valve 8 is subjected to the high-speed on / off control. Is controlled by comparison with the actual value, and finally the pushing load reaches zero, and the process moves to the pulling process. In this pulling process, as shown in FIG. The one direction switching valve 2 is switched to the excitation position to connect the push-side chamber S to the tank T, and the direction switching valve 3 is switched to the non-excitation position to supply the supply line to the pulling-side chamber L of the hydraulic actuator 1. The hydraulic fluid is supplied from 4 and this control pressure is applied to the discharge amount variable pump 7 driven by the servo motor by comparing the target value with the actual value as the feedback signal, as in the pushing load process. When the actual value reaches the target value, the process shifts to the unloading process of the pulling load. In this unloading process of the pulling load, the high-speed on / off valve 8 is controlled at high speed on / off. It is controlled by comparison with the actual value that is a feedback signal, finally the pulling load reaches zero, and if necessary, the process proceeds to the pushing load process again, and the control object is controlled by controlling the operating state of such a hydraulic actuator. A loading test is performed on the test specimen W.

  Therefore, in the pushing load process in which the working liquid is fed from the discharge amount variable pump 7 into the push side chamber S, the working liquid discharged from the pull side chamber L is returned to the push side chamber S by the boost circuit 13. Therefore, it is possible to prevent a decrease in the pushing speed of the rod 1a of the hydraulic actuator 1, to increase the response of the hydraulic actuator to the control signal, and to improve the reliability and stability of the control.

  Further, when it is selected not to use the boost circuit 13 in consideration of the size of the load on the control target W and the predicted fracture load of the specimen, the start of the pushing load process on the control target W is as shown in FIG. The one direction switching valve 2 is left in the non-excitation position, the other direction switching valve 3 is switched to the excitation position, the pulling side chamber L is connected to the tank T, and the hydraulic pressure is turned off when the high-speed on / off valve 8 is off. The hydraulic fluid as hydraulic fluid is supplied from the liquid supply line 4 to the push chamber S of the actuator 1 via the direction switching valve 2, and this control pressure is driven by a servo motor by comparing the target value with the actual value as a feedback signal. The discharge amount variable pump 7 is controlled.

  Then, when the actual value reaches the target value, the process proceeds to the pushing load removing process, and in this pushing load removing process, the high-speed on / off valve 8 is subjected to the high-speed on / off control. Is controlled by comparison with the actual value, and finally the pushing load reaches zero, and the process moves to the pulling process. In this pulling process, as shown in FIG. The one direction switching valve 2 is switched to the excitation position to connect the push-side chamber S to the tank T, and the direction switching valve 3 is switched to the non-excitation position to supply the supply line to the pulling-side chamber L of the hydraulic actuator 1. The hydraulic fluid is supplied from 4 and this control pressure is applied to the discharge amount variable pump 7 driven by the servo motor by comparing the target value with the actual value as the feedback signal, as in the pushing load process. When the actual value reaches the target value, the process shifts to the unloading process of the pulling load. In this unloading process of the pulling load, the high-speed on / off valve 8 is controlled at high speed on / off. It is controlled by comparison with the actual value that is a feedback signal, finally the pulling load reaches zero, and if necessary, the process proceeds to the pushing load process again, and the control object is controlled by controlling the operating state of such a hydraulic actuator. A loading test is performed on the test specimen W.

  In this case, in the pushing load process of feeding the working liquid from the discharge amount variable pump 7 into the push side chamber S, the boost circuit 13 is not used, and the working liquid discharged from the pull side chamber S is supplied to the tank T. Therefore, for example, there is a decrease in the pushing speed of the rod of the hydraulic actuator, but a high output of the pressure side pressure receiving area × the working liquid pressure is exhibited, and the use of the boost circuit 13 or It is possible to select non-use and increase the flexibility of control.

  Further, in this case, since the variable discharge pump 7 is driven by the servo motor 6, the control flexibility and control responsiveness are enhanced by the high output torque characteristics at a high rotation speed and low speed as compared with the inverter motor drive. In this case, the hydraulic actuator 1 is a one-side rod type cylinder having a pressure-side pressure receiving area: pull-side pressure receiving area = 2: 1. The ease and stability of the can be improved.

  In this case, at least the hydraulic actuator 1, the directional switching valves 2 and 3, the discharge variable pump 7, the tank T, and the high-speed on / off valve 8 are integrally mounted. The pipe length of the pipe can be shortened, the delay due to the compressibility of the working liquid in the pipe can be suppressed, the heat generation and the power loss can be suppressed, and the control response and reliability can be improved. Can do.

  It should be noted that the present invention is not limited to the above embodiment, and the form and circuit elements of the hydraulic actuator 1, the direction switching valves 2 and 3, the discharge variable pump 7 and the high-speed on / off valve 8 are appropriately changed. Designed.

  As described above, the intended purpose can be sufficiently achieved.

It is an appearance form figure of an example of an embodiment of the invention. It is a whole hydraulic system circuit diagram of an embodiment of the invention. It is a boost circuit diagram of an embodiment of the present invention. It is a hydraulic-system circuit diagram of the pushing process of the embodiment of this invention. It is a hydraulic-system circuit diagram of the drawing process of the embodiment of this invention. It is a whole hydraulic system circuit diagram of the conventional structure. It is a block diagram of a control process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic actuator 2 Directional switching valve 3 Directional switching valve 4 Supply line 5 Return liquid line 7 Discharge variable pump 8 High speed on / off valve 12 Operation control part

Claims (8)

  A direction switching valve that communicates with the push-side chamber and a direction switching valve that communicates with the pull-side chamber are provided in the hydraulic actuator, and each direction switching valve is connected to a supply liquid line connected to a hydraulic pressure source and a return connected to a tank. A liquid line is connected, a variable discharge pump is provided in the liquid supply line, and a high-speed on / off valve is provided in the liquid supply line, while comparing target values such as load and displacement with actual values. When the operating state of the hydraulic actuator is operated and controlled by the variable discharge pump and the high-speed on / off valve, the hydraulic pump is discharged from the pull side chamber in the pushing load process for supplying the working liquid from the variable discharge amount pump to the push side chamber. A hydraulic actuator control method comprising: returning a working fluid to the push chamber by a boost circuit.   2. The hydraulic actuator control method according to claim 1, wherein the working liquid discharged from the pulling side chamber is returned to the tank in a pushing load process of feeding the working liquid from the discharge amount variable pump into the pushing side chamber. .   3. The hydraulic actuator control method according to claim 1, wherein the discharge amount variable pump is driven by a servo motor.   4. The hydraulic actuator control method according to claim 1, wherein the hydraulic actuator is a one-side rod-type cylinder having a pressure-side pressure receiving area: pull-side pressure receiving area = 2: 1. 5.   A direction switching valve that communicates with the push-side chamber in the hydraulic actuator and a direction switching valve that communicates with the pull-side chamber are provided, and each direction switching valve is connected to a liquid supply line and a tank connected to a hydraulic pressure source. A liquid line is connected, a variable discharge pump is provided in the liquid supply line, and a high-speed on / off valve is provided in the liquid supply line, while comparing target values such as load and displacement with actual values. An operation control unit for calculating and controlling the operation state of the hydraulic actuator by the discharge amount variable pump and the high-speed on / off valve, and at least the hydraulic actuator, the direction switching valves, the discharge amount variable pump, and the tank And a hydraulic actuator control device characterized in that the high-speed on / off valve is integrally mounted.   A direction switching valve that communicates with the push-side chamber in the hydraulic actuator and a direction switching valve that communicates with the pull-side chamber are provided, and each direction switching valve is connected to a liquid supply line and a tank connected to a hydraulic pressure source. A liquid line is connected, a variable discharge pump is provided in the liquid supply line, and a high-speed on / off valve is provided in the liquid supply line, while comparing target values such as load and displacement with actual values. An operation control unit for calculating and controlling the operating state of the hydraulic actuator by the discharge amount variable pump and the high-speed on / off valve, and in the pushing load process of feeding the working liquid from the discharge amount variable pump into the push side chamber, A hydraulic actuator control device comprising a boost circuit for returning the working liquid discharged from the pulling side chamber to the pushing side chamber.   7. The hydraulic actuator control device according to claim 5, wherein the discharge amount variable pump is driven by a servo motor. The hydraulic actuator control device according to any one of claims 5 to 7, wherein the hydraulic actuator is a one-side rod-type cylinder having a push-side pressure receiving area: pull-side pressure receiving area = 2: 1.

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