JP2882954B2 - Automatic gain correction device in hydraulic pressure reduction control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic gain correction device for eliminating a response delay of a pressure-reducing cylinder in hydraulic pressure reduction control, particularly a response delay caused by cylinder hysteresis.

[0002]

2. Description of the Related Art A conventional hydraulic pressure reduction control technique will be described with reference to FIG. In FIG. 3, a rolling cylinder 1 is provided between a housing 2 of a rolling mill and a roll 3, and is connected to a hydraulic pump P through a pressure oil pipe 7 and a servo valve 8 provided in the middle thereof. Reference numeral 4 denotes a ram of the rolling cylinder 1. The pressing down cylinder 1 is provided with a height position detector 5 of the cylinder oil column S. The control device 10 controls the operation of the servo valve 8, and includes a target oil column value transmitting section 11, a reference flow rate gain calculating section 12, an adding section 13, an integrating section 14, a converter 15, and the like. As the control of the pressure reduction cylinder 1, a reference flow rate gain preferable for the operation of the pressure reduction cylinder 1 is obtained in the adjustment stage, and the reference flow rate gain is used as a reference flow rate gain calculation unit 1.
2, the reference oil flow signal from the target oil column value transmitting unit 11 is integrated with the reference flow gain by the integrating unit 14, and a command (servo valve operation signal) is given to the servo valve 8 through the converter 15. Thus, the servo valve 8 is proportionally controlled with a constant reference flow rate gain. Further, the actual height of the oil column S of the rolling-down cylinder 1 is detected by the detector 5 and fed back to the control device 10, and the oil column S is compared by the adding unit 13.
Is controlled to reach the target value.

[0003] When operating the screw-down cylinder 1 by the above-described method, an in-cylinder pressing force (hereinafter, referred to as a cylinder pressure) calculated from the cylinder pressure of the pressure oil sent into the screw-down cylinder 1 via the servo valve 8.
A delay between the actual cylinder pressing force as shown in FIG. 4 is provided between the cylinder pressing force actually acting on the screw-down cylinder 1 (hereinafter referred to as the cylinder actual pressing force). Occurs. This is called cylinder hysteresis, and the cylinder actual pressing force changes along the gentle curve A with respect to the increase in the cylinder pressure, and then increases in proportion to the cylinder pressure increase, as indicated by a straight line B. I do. Also, when the pressure in the cylinder is decreased, the actual pressing force of the cylinder first changes along the gentle curve C, and then decreases in proportion to the pressure in the cylinder as indicated by a straight line D.

The response of the rolling cylinder 1 is delayed as described above, but the degree differs depending on each cylinder.
The response is delayed as the areas of the gentle curves A and C in FIG.
Controllability decreases.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic gain correction device which can eliminate the above-described response delay of the rolling-down cylinder.

[0006]

According to the present invention, there is provided an automatic gain correction device for hydraulic pressure reduction control which achieves the above object, comprising: a hydraulic pressure detector provided in a hydraulic pressure reduction cylinder portion for detecting a hydraulic pressure in a cylinder; A displacement detector for detecting a displacement, calculation units for obtaining a cylinder internal pressure and a cylinder actual pressing force from detection values of the hydraulic pressure detector and the displacement detector provided in the control unit, respectively, and outputs of these calculation units A calculating unit and a limiter processing unit for obtaining a gain correction rate corresponding to the gain change rate of the rolling-down cylinder, a gain correction rate output from the limiter processing unit, and a integrating unit for integrating and correcting the gain correction rate to the reference flow rate gain. And an integrating unit for integrating the output to the target oil column signal and supplying the corrected signal to the servo valve.

[0007]

[Action]

(1) The reference flow rate gain and the target oil column signal are provided by the reference flow rate gain calculation unit and the target oil column value transmission unit as before. (2) Each of the hydraulic pressure detector and the displacement detector provided in the pressure reduction cylinder section continuously and repeatedly detects the in-cylinder oil pressure and the cylinder oil column, for example, at minute time intervals, and sends each detected value to the control device side. (3) In the control apparatus, first, from the detection signal and the detection signal of the cylinder oil pillars displacement cylinder hydraulic, and cylinder pressure F _P for each detected cylinder pressure calculating section, respectively with the cylinder actual pressing force calculating unit cylinder The actual pressing force F _R is calculated and passed to the gain change rate and gain correction rate calculation unit. (4) The calculation unit for the gain change rate and the gain correction rate finds the gain change rate K by, for example, the following equation (1), and passes the reciprocal 1 / K to the limiter processing unit as the gain correction rate.

(Equation 1) (5) The limiter processing section processes the gain correction rate 1 / K in a certain range, for example, in the range of 1 ≦ 1 / K ≦ 5, and passes the processed value to the integrating section. (6) The integrating section integrates the gain correction rate subjected to the limiter processing with the reference flow rate gain to obtain a corrected flow rate gain, and transfers the corrected flow rate gain to the next integrating section. (7) The integrating section integrates the corrected flow rate gain into the target oil column signal, and transmits the integrated signal to the servo valve through, for example, a converter. (8) Thus, servo valve adjustment is performed. This operation is repeated under the feedback control, and the hydraulic pressure reduction cylinder is controlled with the flow rate gain corrected to the optimum flow rate gain corresponding to the gain change rate of the pressure reduction cylinder, and as a result, it is generated by cylinder hysteresis. The cylinder response delay is automatically eliminated.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an automatic gain correction device in hydraulic pressure reduction control according to one embodiment of the present invention. In FIG. 1, a rolling cylinder 1 is provided between a housing 2 of a rolling mill and a roll 3, and is connected to a hydraulic pump P through a hydraulic oil pipe 7 and a servo valve 8 provided in the middle thereof. Reference numeral 4 denotes a ram of the rolling cylinder 1. A displacement detector 5 for detecting the displacement S of the cylinder oil column and a hydraulic pressure P in the cylinder
A hydraulic pressure detector 6 for detecting _r is provided. The control device 10 operates and adjusts the servo valve 8, and includes a target oil column value transmitting unit 11, a reference flow gain calculating unit 12, and an adding unit 1.
3, the automatic gain correction unit 20, the integration units 25 and 26
And a conversion unit 27.

The adder 13 compares the displacement signal S of the cylinder oil column from the displacement detector 5 with the target oil column signal from the target oil column transmitter 11 for feedback control.

The automatic gain correction section 20 includes an in-cylinder pressure calculation section 21, an actual cylinder pressing force calculation section 22, a gain change rate and gain correction rate calculation section 23, and a limiter processing section 24.
Is included. Each function will be described later in detail.

The integrating section 25 integrates the gain correction rate output from the limiter processing section 24 with the reference flow gain from the reference flow gain calculating section 12 and outputs a corrected flow gain. The integrating section 26 integrates the corrected flow rate gain output by the integrating section 25 with the target oil column signal from the adding section 13. The converter 27 converts the signal output from the integrating section 26 into an analog signal. The signal is converted to a signal and transmitted to the servo valve 8 as a servo valve operation signal.

[0012] cylinder pressure calculation unit 21 of the automatic gain correction unit 20 includes a hydraulic power P _r of the cylinder from the hydraulic detector 6 of the screw-down cylinder 1 comes passed repeatedly continuously at short time intervals, previously From the set cylinder cross-sectional area A, the in-cylinder pressure F _P (that is, the calculated cylinder pushing force) of the screw-down cylinder 1 is repeatedly calculated by the following equation (2).

F _P = A · P _r × 10 ⁻³ Equation (2)

The cylinder actual pressing force calculation unit 22 includes a cylinder oil column displacement signal S continuously and repeatedly delivered from the displacement detector 5 of the screw-down cylinder 1 at minute time intervals, and a preset mill constant M [ calculated from TON / mm] Repeat cylinder actual pressing force F _R by the following equation (3).

F _R = M · S Formula (3)

Calculation section 2 for gain change rate and gain correction rate
3 calculates the gain change rate K by the following equation (4) and calculates the reciprocal 1 / K as the gain correction rate.

(Equation 4)

The limiter 24 has a gain correction rate 1 / K
Is processed in the range of the following equation (5) and passed to the integrating section 25.

[Expression 5] 1 ≦ 1 / K ≦ 5 Expression (5)

The corrected flow rate gain is output from the integrating section 25 and sent to the next integrating section 26, where the target oil column signal is integrated with the corrected flow rate gain and the servo valve operation signal is used as the servo valve operation signal. 8 is output.

FIG. 2 shows a control flow performed by using the above automatic gain correction device. When controlling the reduction cylinder 1, first, in the adjustment stage, as shown in steps S10 to S12 of FIG. 2, an optimal flow gain is selected by measurement while operating the reduction cylinder 1 in the same manner as in the related art, and this is set as a reference flow gain. Is set in the reference flow rate gain calculator 12.

In the actual operation stage of the pressure-reducing cylinder 1, FIG.
As shown in step S20 to S22, firstly, the target oil column value S _0, into the automatic operation is performed with the cylinder cross-sectional area A, the setting of the mill modulus M.

In the automatic operation, as shown in steps S23 to S33, the servo valve 8 is adjusted with the initially set reference flow rate gain to operate the screw-down cylinder 1, and the detector 5,
Cylinder oil column displacement S and the cylinder pressure P _r is detected input to the control device 10 from 6, operation unit 21, 22, 23 cylinder pressure F _P, the cylinder actual pressing force F _R, the gain change rate K, the correction The ratios 1 / K are calculated, and the accumulators 26 and 27 correct the reference flow gain and the target oil column value, respectively, through the limiter processing unit 24, adjust the servo valve 8, and adjust the pressure reduction cylinder 1 with the corrected flow gain. Operate. Then, the operation in this order is automatically repeated.

[0020] That oil pressure P _r and the displacement amount S of the screw-down cylinder 1 is fed back, the flow gain correction corresponding to the respective change rates are performed automatically, optimal flow gain the full operating range of the pressure cylinder 1 Is supplied. As a result, the response delay of the cylinder operation caused by the cylinder hysteresis shown as the areas A and C in FIG. 4 is eliminated.

[0021]

As described above, the automatic gain correction device according to the present invention is provided with the in-cylinder oil pressure detector and the cylinder oil column displacement detector in the hydraulic pressure lowering cylinder portion, and the control device portion detects the two detectors. A calculation unit for obtaining a cylinder internal pressure and an actual cylinder pressing force from a value, a calculation unit for obtaining a gain correction rate corresponding to a gain change rate of a screw-down cylinder from outputs of both the calculation units, and a limiter processing unit; The feedback control is provided by including an integrating section for integrating and correcting the gain correction rate output from the section to the reference flow rate gain, and an integrating section for integrating and correcting the output of the arithmetic section to the target oil column value and supplying the corrected value to the servo valve. Flow rate gain that is optimally corrected according to the gain change in the entire operating range of the hydraulic pressure reduction cylinder under pressure, and therefore, the series gain caused by the cylinder hysteresis can be provided. A delay in response of da behavior can be accurately resolved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an automatic gain correction device according to one embodiment of the present invention.

FIG. 2 is a view showing a control flow of the apparatus of the embodiment.

FIG. 3 is a block diagram showing a conventional example.

FIG. 4 is an explanatory diagram of a response delay of a rolling-down cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pressure lowering cylinder 5 Displacement detector 6 Oil pressure detector 8 Servo valve 10 Control device 20 Automatic gain correction unit 21 In-cylinder pressure calculation unit 22 Cylinder actual pressing force calculation unit 23 Gain change rate and gain correction rate calculation unit 24 Limiter processing unit 25 Reference Flow Rate Gain Correction Accumulator 26 Target Oil Column Signal Correction Accumulator 27 Converter

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B21B 37/00

Claims (1)

(57) [Claims] 1. A hydraulic pressure detector provided in a hydraulic pressure lowering cylinder for detecting a hydraulic pressure in a cylinder, a displacement detector for detecting displacement of a cylinder oil column, and a hydraulic pressure detector and a displacement provided in a control unit, respectively. A calculation unit for obtaining a cylinder pressure and an actual cylinder pressing force from a detection value of a detector, and a calculation unit and a limiter processing unit for obtaining a gain correction rate corresponding to a gain change rate of the screw-down cylinder from outputs of both of the calculation units. An integration unit that integrates and corrects the gain correction rate output from the limiter processing unit to a reference flow rate gain, and an integration unit that integrates and corrects the output of the integration unit to a target oil column signal and supplies the signal to a servo valve. An automatic gain correction device for hydraulic pressure reduction control.