JPH01113106A - Hydraulic screw down control device - Google Patents

Abstract

PURPOSE:To smoothen follow-up speed difference of a hydraulic drafting device and to rapidly control the device by calculating a correction amount based on a value obtained by squaring an excess value when a difference between respective deviations of both the hydraulic screw down devices at rolling roll ends exceeds an allowable value. CONSTITUTION:In case of controlling a position of hydraulic draft devices to be constant, a target value of constant position control is previously set in a hydraulic draft controller 1. First, a present position of a screw down cylinder 6 is detected by a cylinder position detector 7 and the position is inputted to the controller 1 through a cylinder position computing element 11 as a present value 13. The controller 1 finds deviation between a target value and a position signal 13 as to both the screw down devices at rolling roll ends, then calculates a difference between respective deviations at both ends, and decides whether the difference does not exceed the allowable value. If the difference exceeds the allowable value, the controller 1 calculates a correction value by squaring the excess value and multiplying the squared value by a coefficient corresponding to characteristics, etc., of respective screw down devices as necessary.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a hydraulic pressure reduction control device that performs localization/constant pressure control using the pressure reduction blades and cylinder positions of two reduction cylinders attached to both sides of a rolling roll as feedback signals. Regarding.

<Prior art> In a hydraulic pressure reduction control device that controls the position/constant pressure of a hydraulic pressure reduction device attached to both sides of a rolling roll, conventionally, when the difference in deviation on both sides exceeds a certain tolerance, The amount of correction was calculated from the difference in deviation itself, and this was added to the deviation on each side to control the tracking so that it was uniform on both sides.

<Problems to be Solved by the Invention> A conventional drawback of this method is that the amount of correction when the difference in deviation between the hydraulic lowering devices on both sides exceeds a tolerance value is primarily determined from the difference in deviation. If the difference in the same deviation changes after the allowable value n, the correction amount is added to the deviation on each side in a step function manner, making it impossible to control smoothly. Further, when the correction amount is multiplied by a coefficient so as to keep the step amount change small, the response when the difference in deviation is large is significantly reduced.

Means for Solving the Problems> The present invention has been made in view of the above problems, and has the following features: By calculating the correction amount based on the square of the difference in deviation that exceeds the allowable value, if the difference in deviation changes around the allowable value, the correction amount is kept small and the step function is used. It is characterized by eliminating the change in the target value, and quickly controlling by an emphasis operation using the square power when the tolerance value is greatly exceeded.

This makes it possible to smoothly and quickly control the difference in follow-up speed between the hydraulic lowering devices on both sides to within the allowable value.

Embodiment FIG. 1 shows an embodiment of the present invention. In the same figure, the rolling
The lever R receives a reduction blade from an upper and lower hydraulic reduction device operated by a reduction cylinder 6. The position of the reduction cylinder 6 is detected by a cylinder position detector 7, and this position detection signal 8
is the cylinder position signal 13 by the cylinder position calculator 11.
This is input to the hydraulic pressure reduction control device 1. On the other hand, the rolling blade is detected by the rolling force detector 9, and this rolling force detection signal 10 is converted into a cylinder rolling blade signal 1 by A/D conversion@g12.
4 and is input to the hydraulic pressure reduction control device 1. In the hydraulic pressure reduction control device 1, a target value for localization control is preset when localization control is performed, and a target value for constant pressure control is preset when constant pressure control is performed. The hydraulic pressure reduction control device 1 performs calculations to be described later and outputs a manipulated variable 2.

The servo amplifier 3 controls the servo valve according to the manipulated variable 2.
! 4, the servo valve 5 is actuated to control the pressure reduction cylinder 6.

Here, a case will be described in which localization control is performed on a hydraulic pressure lowering device, which is an embodiment of the present invention.

In this case, the target value for localization control is set in advance in the hydraulic pressure reduction control device 1. First, the current reduction cylinder 6
After the position of is detected by the cylinder position detector 7,
The current value 13 is inputted to the hydraulic pressure reduction control device 1 via the cylinder position calculator 11 . The hydraulic pressure reduction control device 1 calculates the deviation between the target value and the cylinder position signal (current value) 13 for the hydraulic pressure reduction devices on both sides of the rolling roll, calculates the difference between the deviations on both sides, and calculates the difference between the deviations on both sides. Determine whether the value is within the range. If the allowable value is exceeded, the amount exceeded is squared, and if necessary, the correction amount is calculated by multiplying by a coefficient suited to the characteristics of each hydraulic pressure lowering device. The correction amount obtained in this way has quadratic curve characteristics as shown by the solid line in Figure 2,
Not only is there no step function-like change that conventionally occurs when the deviation difference exceeds the allowable value, but the response when the deviation difference Δε is large is greatly improved. The broken line in FIG. 2 shows the conventional correction amount, and ±σ shows the width of the allowable value.

The correction amount obtained in this way is the operation i to the servo amplifier.
2 is output and localization control is performed.

In the case of constant pressure control, a target value for constant pressure control is set in advance in the hydraulic pressure reduction control device 1, a deviation between this target value and the cylinder reduction blade signal 14 is taken, and control similar to the above-mentioned localization control is performed.

<Effects of the Invention> As explained above, in the present invention, when the difference in deviation between the hydraulic rolling devices on both sides of the rolling roll exceeds a tolerance value, the excess amount is reduced by 2.
By finding the correction amount from the multiplied value, it is possible to eliminate the step function-like operation that conventionally occurs when exceeding the allowable value (and thereby smoothly and quickly bring the difference in follow-up speed between the hydraulic lowering devices on both sides within the allowable value. It was possible to control it.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of the hydraulic pressure reduction control device of the present invention, and FIG.
The figure is a characteristic diagram showing the relationship between the difference in control deviation and the correction amount. In the figure, 1 is the hydraulic pressure reduction control device, 2 is the operation amount to the servo amplifier, 3 is the servo amplifier, 4 is the control amount to the servo valve, 5 is the servo valve, 6 is the reduction cylinder, 7 is the cylinder position detection temperature , 8 is a position detection signal, 9 is a reduction force detector, 10 is a reduction force detection signal, 11 is a cylinder position calculator, 12 is an A/D converter, 13 is a cylinder position signal, and 14 is a cylinder reduction blade signal. . Figure 1

Claims (1)

[Claims] A detection signal that detects the control amount of a hydraulic lowering device installed on both sides of the rolling roll is input, and based on this input detection signal, the current value on one side of the hydraulic lowering device is determined. and the target value, and the deviation between the current value and the target value on the other side of the hydraulic pressure reduction device, and also calculate the difference between the deviation on one side and the deviation on the other side. In a hydraulic pressure reduction device that corrects the control amount of the hydraulic pressure reduction device when exceeds the tolerance value, square the value of the calculated difference that exceeds the tolerance value, and use this squared value as the correction control amount. A hydraulic pressure reduction control device characterized by controlling the device.