JPH06200906A - Servo valve control device in hydraulic servo system - Google Patents

Abstract

PURPOSE:To realize a hydraulic servo system with high speed and with high accuracy without generating any oil hammer phenomenon. CONSTITUTION:In a servo valve control device for feedback-controlling operation of a servo valve 1 in a hydraulic servo system, a gain setting means 3 is provided to set gain variably in the hydraulic servo system including the above mentioned servo valve 1 according to a gain setting signal by inputting the gain setting signal, and also a gain setting signal generating means 5 is provided to receive a control amount in the hydraulic servo system as its input to generate, the gain setting signal according to the control amount, and this signal to the gain setting means 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo valve controller for a hydraulic servo system, and more particularly to a servo valve controller for feedback controlling the operation of a servo valve.

[0002]

2. Description of the Related Art Generally, in a feedback control type hydraulic servo system, when a positioning module receives an operation command, the positioning module gives a spool opening command to a servo valve control device, and the servo valve control is performed in response to this. When the device drives the servo valve, the flow rate of the hydraulic pressure to the hydraulic cylinder device is controlled, the displacement of the piston occurs due to the flow rate control of the hydraulic pressure to the hydraulic cylinder device, and the displacement amount of this piston is detected by the displacement sensor. The piston displacement amount is fed back to the positioning module.

[0003]

In the hydraulic servo system of the feedback control system as described above, for example, in order to drive the ram by the nibbling pattern in the punch press, the piston of the hydraulic cylinder device is moved from the initial position to the ram position. If the loop gain of the hydraulic servo system is increased when the piston is returned to the original initial position and then reciprocally moved to the predetermined control target position that is the bottom dead center position, the time delay and the control target value While the deviation decreases, the deviation increases before the piston returns to the original initial position, and the oil hammer phenomenon occurs.

The present invention has been made by paying attention to the above-mentioned problems in the conventional hydraulic servo system, and reduces the oil hammer phenomenon to reduce the vibration, and at the same time, the hydraulic servo system has high speed and high accuracy. It is an object of the present invention to provide a servo valve control device that can realize the above.

[0005]

According to the present invention, there is provided a servo valve control device for feedback-controlling the operation of a servo valve of a hydraulic servo system, wherein a gain setting signal is inputted and the gain is set. This is achieved by a servo valve control device for a hydraulic servo system, which includes gain setting means for variably setting a gain of a hydraulic servo system including the servo valve according to a setting signal. Moreover, in the servo valve control device of the hydraulic servo system, the control amount in the hydraulic servo system is input, a gain setting signal is generated according to the input control amount and the state amount in the servo amplifier, and this is output to the gain setting means. It is desirable to have a gain setting signal generating means for

[0006]

According to the above configuration, the gain setting signal generating means inputs the control amount in the hydraulic servo system and generates the gain setting signal according to the control amount, and the gain setting signal is used by the gain setting means. Variably sets the gain of the hydraulic servo system according to the control amount of the hydraulic servo system, in other words, the operating state of the hydraulic servo system.

[0007]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the basic construction of a servo valve control device for a hydraulic servo system according to the present invention. This hydraulic servo system has a servo valve 1 as a control target, a gain setting means 3, and a gain setting signal generating means 5.

The servo gain setting means 3 is given a control deviation E due to the difference between the target value R and the opening degree of the servo valve 1 detected by the position detector, that is, the control amount Y of the servo valve 1, and inputs the gain. Gain K according to the setting signal Ks
Is set and the manipulated variable signal U is output to the servo valve 1.

The gain setting signal generating means 5 receives the control amount Y of the servo valve 1, generates a gain setting signal Ks which changes according to a predetermined characteristic according to the control amount Y, and outputs this gain setting signal Ks. Servo gain setting means 3
It is designed to output to.

As a result, the gain K of the hydraulic servo system changes in accordance with a predetermined characteristic according to the control amount Y of the servo valve 1.

2 and 3 show an embodiment in which a hydraulic servo system including a servo valve control device according to the present invention is applied to a ram drive device of a turret punch press. As shown in FIG. 2, the turret punch press holds the punch 13 on the upper turret disk 11 and the die 17 on the lower turret disk 15. The punch 13 is located immediately below the striker 21 connected to the ram 19 at the press position and is pressed by the striker 21.

The ram 19 is connected to the piston rod 25 of the hydraulic cylinder device 23, and is reciprocally driven in the vertical direction by the hydraulic cylinder device 23. The hydraulic cylinder device 23 is a reciprocating hydraulic cylinder device having cylinder chambers 29 and 31 on both sides of the piston 27.
By supplying hydraulic pressure to the cylinder chamber 31, the ram 19
Is designed to drive up.

The linear servo valve 33 quantitatively supplies and discharges hydraulic pressure to and from the cylinder chambers 29 and 31.

The linear servo valve 33 is an electromagnetically-actuated linear servo valve, and is configured to quantitatively change the spool opening according to the current applied to the linear drive magnet 35. A hydraulic pressure is supplied from a hydraulic pressure supply system including a pressure regulation valve 39, and the cylinder chamber 29,
The flow rate of hydraulic pressure supplied to 31 is quantitatively controlled.

The servo valve controller 41 controls the current applied to the linear drive magnet 35 of the linear servo valve 33.

As shown in FIG. 3, the servo valve control device 41 has a spool opening command generator 43, a spool position amplifier 45, and a current amplifier 47.

The spool opening command generator 43 generates a spool opening command signal and outputs the spool opening command signal to the combining point 49, which then sends the spool opening command signal to the linear servo valve 33. A control deviation due to a difference from the position feedback signal indicating the spool position of the linear servo valve 33 detected by the position detector 51 provided is output to the spool position amplifier 45.

The spool position amplifier 45 is a variable gain type amplifier, which sets a gain according to the input gain setting signal, amplifies the control deviation with the gain, and outputs it as a speed command signal to the summing point 53. It has become.

At the summing point 53, the control deviation due to the difference between the speed command signal and the speed feedback signal output by the differentiator 55 for differentiating the position feedback signal is used as the current amplifier 4.
It is designed to output to 7.

The current amplifier 47 amplifies the input control deviation with a predetermined amplification degree and supplies the valve drive current to the linear drive magnet 35 of the linear servo valve 33.

The gain setting circuit 57 outputs the gain setting signal input to the spool position amplifier 45. The gain selection circuit 57 inputs the position feedback signal from the position detector 51 and the velocity feedback signal from the differentiator 55, detects the piston displacement of the hydraulic cylinder device 23 from these, and is shown in FIG. As described above, in the reciprocating drive of the ram 19, the piston displacement becomes the maximum from the zero point (initial position), and then the piston displacement becomes the zero point from the area A returning to near the zero point and the point returning to near the zero point. Determine the area B until returning to the area A
In the area B, the gain setting signal for setting the gain to a relatively large value is output to the spool position amplifier 45, and in the area B, the gain setting signal for setting the gain to a relatively small value is output to the spool position amplifier 45. Is configured to.

According to the above description, in the reciprocating drive of the ram 19, the piston displacement becomes maximum from the zero point (initial position) and then returns to near the zero point in the region A.
The gain selection circuit 57 outputs a gain setting signal for setting the gain to a relatively large value to the spool position amplifier 45,
As a result, in this area A, the gain of the spool position amplifier 45 is set to a relatively large value. As a result, in the region A, the time delay and the deviation with respect to the control target value become small, the quick response and high accuracy are maintained, and the ram 19 can be driven at high speed.

On the other hand, in the region B from when the piston displacement returns to near zero to when the piston displacement returns to zero, the gain of the spool position amplifier 45 is set to a relatively small value. This prevents the oil hammer phenomenon from occurring in the region B.

FIG. 4A shows the speed change and the spool displacement of the spool of the linear servo valve 33 under the gain adjustment as described above, and FIG. 4B shows the hydraulic cylinder device 23 at this time. Shows the piston displacement characteristics of.

That is, in the nibbling process, for example, in the first shot and the second shot, the gain is increased as shown by the solid line in FIG. 5, and the gain is increased to move from the first shot to the second shot, that is, the clamped work is moved. The gain can be switched by the gain selection circuit 57 so that the gain becomes small as shown by the dotted line when the gain is set. Therefore, the vibration becomes low during the nibbling process, and the vibration noise can be reduced.

In the above, the present invention has been described in detail with respect to a specific embodiment, but the present invention is not limited to this, and various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art. In FIG. 1, the gain setting signal generating means 5 may be provided outside in advance without taking in the feedback of the control amount of the servo valve 1 as shown by the chain double-dashed line.

[0028]

As can be understood from the above description, according to the servo valve control device of the present invention, the gain setting signal generating means inputs the control amount in the hydraulic servo system and the gain is adjusted according to the control amount. A setting signal is generated, and the gain setting signal variably sets the gain of the hydraulic servo system according to the operating state of the hydraulic servo system by the gain setting signal. A highly accurate hydraulic servo system will be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a servo valve control device for a hydraulic servo system according to the present invention.

FIG. 2 is a configuration diagram of essential parts showing an embodiment in which a hydraulic servo system including a servo valve control device according to the present invention is applied to a ram drive device of a turret punch press.

FIG. 3 is a block diagram showing an embodiment of a servo valve control device when a hydraulic servo system including the servo valve control device according to the present invention is applied to a ram drive device of a turret punch press.

FIG. 4A shows a speed change and a spool displacement of a linear servo valve spool under a gain adjustment by the servo valve control device according to the present invention, and FIG. 4B shows a piston displacement of the hydraulic cylinder device at this time. It is a graph which shows a characteristic.

FIG. 5 is a graph showing the relationship between spool opening and piston displacement in a hydraulic servo system in nibbling processing.

[Explanation of symbols]

 1 servo valve 3 gain setting means 5 gain setting signal generating means 13 punch 17 die 19 ram 21 striker 23 hydraulic cylinder device 33 linear servo valve 41 servo valve control device 43 spool opening command generator 45 spool position amplifier 47 current amplifier 51 position Detector 57 Gain selection circuit

Claims (2)

[Claims] 1. A servo valve control device for feedback controlling the operation of a servo valve of a hydraulic servo system, comprising:
A servo valve control device for a hydraulic servo system, comprising: a gain setting means for inputting a gain setting signal and variably setting a gain of a hydraulic servo system including the servo valve according to the gain setting signal. 2. A gain setting signal generating means for inputting a control amount in a hydraulic servo system, generating a gain setting signal according to an input control amount and a state amount in a servo amplifier, and outputting the gain setting signal to a gain setting means. The servo valve control device for a hydraulic servo system according to claim 1, characterized in that it has.