JPS6360013A - Hydraulic roll reduction controller for mandrel mill - Google Patents

Abstract

PURPOSE:To contrive improvements of a control accuracy and uniformity of speeds, by disposing a position control system and a speed compensating circuit with respect to each hydraulic cylinder and digital controlling a cylinder positioning servo system. CONSTITUTION:As for the hydraulic unit 5a-5d of the each hydraulic cylinder 2a-2d, a servo arithmetic parts 4a-4d of a digital input, analogue output type is disposed. A servo amplifier 43 drives an electro-mechano-transducer 53 of a servovalve 51 corresponding to a command input to supply a pressure oil to each cylinder 2a-2d. At this time, the cylinder position control by the servovalve 51 is performed as the digital feedback control for the real position following a digital position command signal. Because the speed compensation is conducted for the servo system together with the digital controlling, the accuracy and the speed uniformity in the hydraulic rolling reduction control are improved.

Description

[Detailed Description of the Invention] [Industrial Application Denominator] The present invention relates to a mandrel mill hydraulic reduction control device, and more specifically, to a device for reducing cropping due to thickening of the tube end in a stretch reducer in the next process. The present invention relates to a hydraulic pressure reduction control device for preforming a tube end into a thin tapered shape using a mandrel mill.

[Conventional technology]

In a hot seamless steel pipe production line where the final finishing process is a straight cut reducer, the cropping becomes thicker due to the thickening of the pipe end at the reducer, resulting in a significant drop in yield. One way to overcome this drawback is to
During rolling in a mandrel mill, which is a pre-process, the corresponding pipe end is preformed thinly into a tapered shape.
The goal is to offset it. Special Public Service No. 51-43825
The publication discloses a mandrel mill hydraulic reduction control for this purpose, in which several drum-shaped reduction rolls surrounding the rolled tube are arranged in one stand, and each roll is used for separate reduction. It is driven by a hydraulic cylinder, and the rolling position of all cylinders is moved at a controlled speed as the rolled raw tube passes (this is how the tube end is preformed into a tapered shape. In this case Of course, it is necessary to perform positioning control of each cylinder with relatively high speed and high precision, and sufficient precision is also required for uniform speed of all cylinders.In this way, high speed uniformity is required. In general, in many cases, a tuning control circuit is attached to each cylinder position control system, but although the tuning control circuit method can be expected to be effective in low-speed systems, it is not suitable for high-speed systems such as this device, and in transient parts. However, sufficient effect cannot be obtained,
Furthermore, when a tuned control circuit is employed, there is an unavoidable drawback that if a problem occurs in one of the cylinder control systems, it will interfere with the other cylinders as well.

[Problem that the invention seeks to solve]

An object of the present invention is to eliminate the drawbacks of the prior art described above, to obtain highly accurate speed uniformity of each cylinder, and to achieve high speed and
An object of the present invention is to provide a mandrel mill hydraulic pressure reduction control equipment for pipe end preforming that enables cylinder positioning control to StrT degrees.

[Means for solving problems]

In order to achieve the above-mentioned problems, the mandrel mill hydraulic reduction control device for pipe end preforming of the present invention preforms the pipe end into a thin tapered shape when the rolled blank pipe passes through the rolling line. Each of the plurality of hydraulic cylinders arranged therein for controlling the positioning of the reduction rolls is equipped with a digitally controlled hydraulic cylinder position control system and a speed compensation circuit for smoothing transient characteristics of the control system. .

In one embodiment of the present invention, the speed compensation circuit includes a sensor that detects the position of the hydraulic cylinder, a counter circuit that outputs digital data corresponding to the cylinder position detected by the sensor as a position signal, and a counter circuit that outputs digital data corresponding to the cylinder position detected by the sensor as a position signal. It includes a conversion circuit that converts a digital position signal from a circuit into an analog signal, and a differentiation circuit that differentiates the analog signal and supplies it as a speed compensation signal to a servo calculation section of a valve for controlling the hydraulic cylinder, and the hydraulic cylinder position control The system includes a digital calculation means for outputting a Denkle deviation (No. 1) corresponding to the deviation between the digital position signal from the counter and the cylinder position setting digital command signal, and a digital calculation means for outputting a Denkle deviation (No. and conversion means.

[Effect]

As is clear from the above-mentioned configuration, the hydraulic pressure reduction control device of the present invention does not employ a method using a synchronized control circuit to ensure uniform speed of each cylinder, but uses a digital control system to control the position control system of each hydraulic cylinder. The above object is achieved by obtaining high response and high precision, and smoothing the transient characteristics by improving the damping effect by the speed compensation control circuit.

For a better understanding of the present invention, preferred embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.
The outline of the configuration of the hydraulic pressure reduction system is shown for the hydraulic cylinder devices 2a to 2d in this book, especially No.
Regarding the 4-cylinder 2d, the configuration contents of the servo calculation section and the hydraulic unit are also shown.

In FIG. 1, a block 10 conceptually represents a higher-level processor controller for rolling control, and a hydraulic pressure reduction command as a cylinder position setting command signal is given from block 10 as a binary signal of, for example, 16 bits and atto.

The cylinder position setting command No. 43 is input to the cylinder position command digital calculation unit 3, where cylinder position commands to the servo calculation units 411 to 4d of each cylinder are calculated. This calculation unit 3 may be, for example, a dedicated microcomputer.

The servo calculation units 4a to 4d have digital inputs and controls that control hydraulic units 58 to 5d that control the drive oil pressure of each cylinder.
It is an analog output type control amplifier, and its configuration is No.
The 4 servo and ¥L calculating section will be described later.

Cylinder output position detectors i6a to 6d, such as Magnescale, are attached to each cylinder 1a to 1d.

The hydraulic units 5a to 5d, as shown for the positive 4 unit, include a servo valve 51 that controls the supply of pressure oil to the cylinder 2d, and are also provided with a pressure detector 52 that detects the pressure of pressure oil to the cylinder. . The servovalve 51 is equipped with an electro-mechanical converter 53 for its drive and a differential transformer 54 for position feedback of its 81 reduced output.

The servo calculation units 48 to 4d include a D/A converter 41 that converts the cylinder position command (digital deviation No. 43) from the digital calculation unit 3 into an analog signal, as shown for lJo, 4 servo calculation unit 4d. , a correction calculation circuit 42 that performs various correction calculations on the analog signal from this D/A converter 41, and a servo that drives the electro-mechanical converter 53 of the servo valve 51 using the output of the correction calculation circuit 42 as a command input. An amplifier 43, a differential transformer amplifier 44 which adjusts the gain of the position feedback signal from the differential transformer 54 and supplies it to the servo amplifier 43 as a differential input, and a differential transformer amplifier 44 which adjusts the span and gain rIQ of the detection output of the pressure detector 52. A differential pressure compensation circuit 45 that inputs a correction signal to the correction calculation circuit 42, a detector 46 that generates an up signal and a down signal from the output of the position detector 6d, and a digital counting system that counts these up and down signals. An amplifier down counter 47 that outputs the output as a cylinder position signal of, for example, a 16-bit binary signal to the digital calculation section 3, a D/A converter 48 that converts this digital cylinder position signal into an analog signal, and a D/A converter 48 that converts this digital cylinder position signal into an analog signal. A differentiation port f% 49 is provided for differentiating an analog cylinder position signal and inputting the resultant signal to the correction calculation circuit 42 as a speed compensation signal.

Incidentally, the digital calculation unit 3 calculates the cylinder position command from the cylinder position command digital signal from the host program controller and the detected cylinder position digital signal (No. 3) from the up/down counter 47, and outputs the cylinder position command as a digital deviation signal. The signal is supplied to the servo amplifier 43 via the /A converter 41 and the correction calculation section 42.

Although the above description of the configuration of the servo calculation unit is for the No. 4 cylinder, the same applies to the servo calculation unit for the No. 3 cylinders NL1 to No. 3.

In the mandrel mill hydraulic pressure reduction control device having the above configuration, the digital calculation unit 3 receives the reduction position of each cylinder from the position detectors 68 to 6d through the respective servo calculation units 4a to 4d, and calculates the reduction position by the up/down counter (47). It is given as a digital signal as a numerical value. The rolling down signal from the upper process controller 10 is a cylinder position command that changes in a preprogrammed pattern to offset the phenomenon of tube end thickening in the next process stretch reducer that occurs at the tube end of the rolled blank tube. This command is given as a digital command signal from the digital calculation unit 3 to all the servo calculation units 4a to 4d, and the start timing of this control is when the mill load relay is activated when the end of the rolled raw pipe passes. on·
It is given using an off signal etc.

To explain the operation of the cylinder with respect to the magic 4 cylinder 4d, the servo amplifier 43, which has a minor loop formed by the differential transformer 54 and the amplifier 44, drives the electro-mechanical converter 53 of the servo valve 51 in response to command input, valve 5
1 supplies pressure oil to the cylinder 4d in response. The hydraulic pressure to the cylinder 4d is detected by a pressure detector 52,
It is supplied to the correction calculation circuit 42 via the differential pressure compensation circuit 45, and applies pressure compensation feedback to the command signal to the servo amplifier. The cylinder position is detected by the position detection % 116d, and sent to the calculation section 3 as a digital signal by the up/down counter 47 via the detector 46. The digital calculation unit 3 calculates a digital deviation signal from the digital position command signal from the host program controller 10 and this digital position detection signal, and converts this signal into the servo calculation unit 4.
Correction calculation port as an analog signal via the D/A converter 41 of d! It is given to eJ42. The digital cylinder position detection signal from the up/down counter 47 is also input to a differentiation circuit 49 via another D/A converter 48, and its differentiation output is sent to a correction calculation port 'l as a speed compensation signal.
842. The correction calculation circuit 42 performs the differential pressure compensation and speed? The analog command (No. 3) from the D/A converter 41 is corrected by each correction input signal lOgt and then given to the servo amplifier 43.

As a result, the position of the cylinder 2d by the servo valve 51 is digital feedbank control of the actual position according to the digital position command signal 9. This is the same for all cylinders, and each cylinder is controlled by a digital control system with good responsiveness. Since the control is performed by the following, ultimate high-speed and high-precision cylinder positioning is possible for all cylinders. Furthermore, since this servo system is compensated for speed by the speed detection signal, transient characteristics are smoothed out by improving the damping effect by speed me when there is a sudden change in the command. It also increases the sex.

[Effects of the Invention] As described above, according to the present invention, since the position feedback control system is configured with a digital control system for the servo system for cylinder control, the responsiveness of each cylinder is extremely high. At the same time, since speed compensation is applied to the servo system, the damping characteristics of the control system are improved, transient characteristics are smoothed, and the overall characteristics are high speed, n-accuracy, and mandrel mill hydraulic pressure with good speed uniformity for all cylinders. A control device is obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, In and ld are rolling rolls, 2a to 2d are hydraulic cylinders for rolling down, 3 is a digital calculation unit, 4a to 4d are servo calculation units, 5a to 5d are hydraulic units, and 6a to 6d
is a position detection type, 10 is a host program controller, 41 is a D/A converter, 42 is a correction calculation circuit, 43 is a servo amplifier, 44 is a differential f# transformer amplifier, 45 is a differential pressure compensation circuit, 46 is a detector, and 47 is a Up/down counter, 48 is a D/A converter, 49 is a differential circuit, 51 is a servo valve, 52 is a pressure detector, 53 is an electro-mechanical converter, 54 is a difference! I!
lIl lance is shown. Masatoshi Sasuke, a substitute junior burial officer

Claims (1)

[Claims] 1. Taper the wall thickness at the end of the rolled raw pipe by controlling the positioning of a plurality of reduction rolls arranged in the rolling line using separate hydraulic cylinders when the rolled raw pipe passes through the pipe end. A mandrel mill hydraulic pressure reduction control device for preforming thinly into shapes, each of which is equipped with a hydraulic cylinder position control system by digital control and a speed compensation circuit for smoothing transient characteristics of the control system. A mandrel mill hydraulic reduction control device featuring: 2. The speed compensation circuit includes a sensor that detects the position of the hydraulic cylinder, a counter circuit that outputs digital data corresponding to the cylinder position detected by the sensor as a position signal, and a digital position signal from the counter circuit. The hydraulic position control system includes a conversion circuit that converts the analog signal into an analog signal, and a differentiation circuit that differentiates the analog signal and supplies it as a speed compensation signal to the servo calculation section of the hydraulic cylinder control valve, and the hydraulic position control system converts the digital position from the counter into It is characterized by comprising a digital calculation means for outputting a digital deviation signal according to the deviation between the signal and the cylinder position setting digital command signal, and a conversion means for giving the digital deviation signal to the servo calculation section as an analog signal. A mandrel mill hydraulic pressure reduction control device according to claim 1.