CN101097439A - Stretch reducing mill wall thickness feed forward combination feedback control method - Google Patents

Abstract

The invention relates to wall thickness control method during course of seamless steel pipe tensility reducing diameter, especially a seamless steel pipe tensility reducing diameter course wall thickness feedforward combining with feedback self-adapting control method. The invention is during course of reducing of seamless steel pipe, firstly, based on wall thickness data obtained by measurement of calibrator which is at export of reducing machine; it corrects rolling rotate speed of roller to overcome wall thickness windage worked by poor production condition and mismatched model; then, based on said rolling rotate speed, comparing hollow forging of steel pipe and wall thickness difference of incoming hollow forging, according to distributing rule of wall thickness, obtaining new self-adapting adjusting method combining feedforward and feedback for rotate speed distribution of roller. Reducing product steel pipe wall thickness difference reduced by wall thickness difference of incoming hollow forging and environment interference can be avoided, coherence of steel pipe wall thickness and controlled objective wall thickness can be realized.

Description

Stretch reducing mill wall thickness feed forward combination feedback control method

(1) technical field

The present invention relates to a kind of wall thickness control method of tension diameter-reducing procedure of seamless steel tube, relate in particular to a kind of based on supplied materials hollow forging wall thickness deviation with open and to subtract the weldless steel tube stretch reducing process wall thickness feed forward of finished product tube wall deviation in conjunction with the feedback adaptive control method.

(2) background technology

Open that to subtract machine be last one texturing machine that the steel pipe hot rolling is produced, the quality of final tube product is played decisive role, therefore, the research of opening the control that subtracts machine is had special significance.Hot rolled seamless steel tube wall thickness deviation in process of production is one of key factor that influences steel pipe hot rolling production recovery rate and fished pipe quality, and the wall thickness deviation of steel pipe therefore how controlled well is the main target of the control system of stretch reducing process.

Steel pipe is realized by adjusting steel pipe tension force between each frame in the wall thickness change of stretch-reducing mill, and the tension force between each frame is produced by the velocity contrast between each roll, therefore controls the stretch reducing mill wall thickness problem and is converted into the tachometer value problem of adjusting each roll.

Opening the tachometer value that subtracts each roll of machine traditionally all is under the stable state rolling condition, according to the desirable material situation, predefined through calculating.Yet, in the stretch reducing process of reality, exist the variation of various inner parameter variations, external disturbance and waste thickness of pipe etc. inevitably, the wall thickness value and the bigger situation of nominal value deviation of steel pipe may take place, this moment must be in actual production process the rotating speed of corresponding each roll of adjustment to remedy the variation of wall thickness.At present, each steel pipe enterprise when steel pipe's production, mainly be production operators according to the produced on-site situation, rely on the rotating speed of experience breaker roll to distribute and manually adjust, reliability and optimality all can not get guaranteeing.

(3) summary of the invention

The object of the present invention is to provide a kind of stretch reducing mill wall thickness feed forward combination feedback control method, this control method is according to the measured data of the rolling front and back of stretch reducing process thickness of steel pipe and the characteristic of steel pipe, adopt the iterative learning control technology, online adaptive is adjusted the rotating speed distribution of each rolling machine frame, the roll rotational speed distribution parameter error that factors such as compensation origin material hollow forging wall thickness change and environmental interference cause in the operation of rolling.

The present invention is achieved in that a kind of stretch reducing mill wall thickness feed forward combination feedback control method, and it comprises following steps:

Step 1, read the relevant criterion technological parameter data of steel pipe to be rolled, subtract the relevant criterion technological parameter data of reading steel pipe to be rolled in the pass schedule, standard pipe weight B by opening _d, standard tandem rolling length of tube L _d, standard tandem rolling external diameter of pipe D ₀ ^d, standard tandem rolling thickness of pipe S ₀ ^d, standard finished products external diameter of pipe D _N ^d, standard finished products thickness of pipe S _N ^d, open and to subtract machine inlet frame working diameter φ ₀ ^d, open and to subtract machine outlet frame working diameter φ _N ^d, open and to subtract machine inlet gantry speed v ₀ ^d, standard opens and subtracts machine outlet gantry speed v _N ^d, the effect frame is when being the m frame $v_N^d=v_m^d;$

Step 2, read the online relevant actual process parameter data that record steel pipe, the online actual wall thickness measured value S that pipe weight B, tandem rolling length of tube L, thickness measurement online instrument are measured that records _N ^k, each frame current of electric measured value and steel pipe arrive the time of each frame end to end, the inlet gantry speed v of each frame ₀ ^kOutlet gantry speed v _N ^k

And actual tandem rolling external diameter of pipe D is set ₀ ^kWith desirable tandem rolling external diameter of pipe D ₀ ^dUnanimity, promptly $D_0^d=D_0^k;$

Step 3, according to formula: $S_0^k=\frac{D_d-\sqrt{D_d^2-4\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="A20061002852200151.png,A20061002852200161.png"\; state="\{\{state\}\}">C</figure-callout>}}}{2},$ Calculate the actual wall thickness S of current tandem rolling pipe ₀ ^k, wherein: $D_d=D_0^d=D_0^k,$ $C=\frac{(D_0^d-S_0^d)S_0^d{L}_{d}B}{L{B}_d};$

Step 4, by the constancy of volume rule, under the stable rolling state, have for desired quantity and the actual numerical value that records:

$(D_0^d-S_0^d)S_0^d{\mathrm{\&phi;}}_0^d{v}_0^d=(D_N^d-S_N^d)S_N^d{\mathrm{\&phi;}}_N^d{v}_N^d---\left(1\right)$

$(D_0^k-S_0^k)S_0^k{\mathrm{\&phi;}}_0^k{v}_0^k=(D_N^k-S_N^k)S_N^k{\mathrm{\&phi;}}_N^k{v}_N^k---\left(2\right)$

$(D_0^{k+1}-S_0^{k+1})S_0^{k+1}{\mathrm{\&phi;}}_0^{k+1}{v}_0^{k+1}=(D_N^{k+1}-S_N^{k+1})S_N^{k+1}{\mathrm{\&phi;}}_N^{k+1}{v}_N^{k+1}---\left(3\right)$

After rotating speed was adjusted, the variation of roll working diameter was little, can obtain:

${\mathrm{\&phi;}}_0^d\&ap;{\mathrm{\&phi;}}_0^k\&ap;{\mathrm{\&phi;}}_0^{k+1}---\left(4\right)$

${\mathrm{\&phi;}}_N^d\&ap;{\mathrm{\&phi;}}_N^k\&ap;{\mathrm{\&phi;}}_N^{k+1}---\left(5\right)$

The external diameter of steel pipe can be obtained by the pass decision of rolling mill roll:

$D_0^d\&ap;D_0^k\&ap;D_0^{k+1}---\left(6\right)$

$D_N^d\&ap;D_N^k\&ap;D_N^{k+1}---\left(7\right)$

According to formula (1), (2), (3) combination (4), (5), (6), (7), and the wall thickness S that guarantees fished pipe _N ^K+1With target wall thickness S _N ^dUnanimity, promptly $S_N^{k+1}=S_N^d,$ The inlet breast roller rotating speed of wall thickness adaptive control is fed back in the combination that obtains feedovering:

$v_0^{k+1}=\frac{(D_0^d-S_0^k)S_0^k}{(D_0^d-S_0^{k+1})S_0^{k+1}}\frac{(D_N^d-S_N^d)S_N^d}{(D_N^d-S_N^k)S_N^k}{v}_0^k---\left(8\right)$

When wall thickness feed forward is controlled in conjunction with feedback adaptive,, keep the rotating speed of outlet roll constant, promptly in order to guarantee rhythm of production $v_N^d=v_N^k;$ In addition, the finishing frame of back mainly participates in the shaping of steel pipe, can keep their roll rotational speed constant, and only allows tension force rise frame and work housing participation speed governing; If allow m-1 frame participate in speed governing, promptly the rotating speed of m frame is fixed, $v_m^k=v_m^d;$ Can respectively be participated in the breast roller speed of speed governing according to the linear expansion form:

$v_i^{k+1}=v_i^k+\frac{(v_m^d-v_i^d)}{(v_m^d-v_0^d)}(\frac{(D_0^d-S_0^k)S_0^k}{(D_0^d-S_0^{k+1})S_0^{k+1}}\frac{(D_N^d-S_N^d)S_N^d}{(D_N^d-S_N^k)S_N^k}-1)v_0^k---\left(9\right)$

In the formula, v _i ^K+1Expression acts on the speed of rolls of the i frame frame of next root steel pipe, i=1, and 2...m-1,

v _i ^d, v _m ^d, v ₀ ^d, D ₀ ^d, D _N ^d, S _N ^dAll be the value of pass schedule initial setting,

S ₀ ^k, S ₀ ^K+1Expression current root tandem rolling wall thickness and next root are wanted the tandem rolling wall thickness of rolled steel tube,

S _N ^kSubtract the actual production tube wall thickness of measuring the current root steel pipe that comes of thicknessmeter behind the machine according to opening,

v _i ^k, v ₀ ^kRepresent current use when rolling open the speed of rolls that subtracts machine i frame and inlet frame;

Step 5 is carried out computing and control to opening the algorithm that subtracts machine on host computer, host computer passes to PLC with signal, controls motor and roll rotational speed by PLC by the parameter of setting;

Step 6 is opened and to be subtracted machine and be rolled the actual value v of the roll rotational speed of the actual achievement collection module real-time collecting steel pipe rolling in the host computer according to the roll rotational speed of setting ₀ ^k, v _i ^kEtc. parameter and note.

The present invention subtracts in the operation of rolling opening of weldless steel tube, at first, subtract production tube wall thickness data according to opening opening that the thicknessmeter on-line measurement subtract the machine exit obtains, revise the rolling rotating speed of each roll, to overcome because the wall thickness deviation that bad production status and model mismatch cause; Then, based on the rolling rotating speed, the wall thickness variation of the hollow forging of rolled steel tube and supplied materials hollow forging more according to the Thickness Distribution rule, obtains feeding back the self-adapting regulation method that the rotating speed of each the new roll that combines with feedforward distributes.Thereby opening of avoiding that origin material hollow forging wall thickness deviation and environmental interference caused subtracts the fished pipe wall thickness deviation, realizes the consistance of the target wall thickness of thickness of steel pipe and control.

(4) description of drawings

The invention will be further described below in conjunction with the drawings and specific embodiments.

Fig. 1 is a stretch reducing mill wall thickness feed forward combination feedback control method block diagram of the present invention;

Fig. 2 is stretch reducing mill wall thickness feed forward combination feedback control method operation synoptic diagram;

Fig. 3 is the peaked distribution schematic diagram of thickness of steel pipe;

Fig. 4 is the distribution schematic diagram of thickness of steel pipe minimum value;

Fig. 5 is the distribution schematic diagram of thickness of steel pipe mean value.

(5) embodiment

Referring to Fig. 2, a kind of stretch reducing mill wall thickness feed forward combination feedback control method, be to subtract in the operation of rolling opening of weldless steel tube, at first, subtract production tube wall thickness data according to opening opening that the thicknessmeter on-line measurement subtract the machine exit obtains, revise the rolling rotating speed of each roll, overcome the wall thickness deviation that bad production status and model mismatch cause; Then, based on the rolling rotating speed, the wall thickness variation of the hollow forging of rolled steel tube and supplied materials hollow forging more according to the Thickness Distribution rule, obtains feeding back the self-adapting regulation method that the rotating speed of each the new roll that combines with feedforward distributes.

Real-time online calculates the mandrel mill-made shell wall thickness

Include desirable pipe weight in the pass schedule opening to subtract, desirable tandem rolling length of tube and desirable tandem rolling wall thickness, at first pipe weight and the tandem rolling length of tube according to online actual measurement compares with ideal value, obtains the mandrel mill-made shell wall thickness of reality.

If desirable pipe weight is B _d, desirable tandem rolling length of tube is L _d, desirable tandem rolling thickness of pipe is S _d, desirable tandem rolling external diameter of pipe is D _d, actual measurement pipe weight is B, and actual measurement tandem rolling length of tube is L, and actual tandem rolling external diameter of pipe is D, and actual mandrel mill-made shell wall thickness is S, it is generally acknowledged actual tandem rolling external diameter of pipe D and desirable tandem rolling external diameter of pipe D _dUnanimity, then the following relationship formula is set up,

$\frac{B_d}{B}=\frac{(D_d-S_d)S_d{L}_d}{(D_d-S)\mathrm{SL}}$

Promptly

$S^2-D_{d}S+\frac{(D_d-S_d)S_d{L}_{d}B}{L{B}_d}=0$

Note $C=\frac{(D_d-S_d)S_d{L}_{d}B}{L{B}_d},$ Then Shi Ji tandem rolling thickness of pipe can followingly calculate $S=\frac{D_d-\sqrt{D_d^2-4\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="A20061002852200151.png,A20061002852200161.png"\; state="\{\{state\}\}">C</figure-callout>}}}{2}.$

Table 1 represents that for opening the ideal value and the actual value that subtract the machine technological parameter parameter of subscript d is the ideal parameters of pass schedule regulation in the table 1, and the parameter of subscript k is the parameter of current rolled steel tube, and the parameter of subscript k+1 is wanted the parameter of rolled steel tube for next root.

Table 1 subtracts machine technological parameter ideal value and actual value is represented

	The tandem rolling external diameter of pipe	The tandem rolling thickness of pipe	The production tube external diameter	The production tube wall thickness	Inlet frame working diameter	Outlet frame working diameter	The inlet gantry speed	The outlet gantry speed
									Ideal value	D 0 d	S 0 d	D N d	S N d	φ 0 d	φ N d	v 0 d	v N d
Current root	D 0 k	S 0 k	D N k	S N k	φ 0 k	φ N k	v 0 k	v N k
									Next root	D 0 k+1	S 0 k+1	D N k+1	S N k+1	φ 0 k+1	φ N k+1	v 0 k+1	v N k+1

Referring to Fig. 1, a kind of stretch reducing mill wall thickness feed forward combination feedback control method, it comprises following steps:

Step 1 reads the relevant criterion technological parameter data of steel pipe to be rolled, subtracts the relevant criterion technological parameter data of reading steel pipe to be rolled in the pass schedule, standard pipe weight B by opening _d, standard tandem rolling length of tube L _d, standard tandem rolling external diameter of pipe D ₀ ^d, standard tandem rolling thickness of pipe S ₀ ^d, standard finished products external diameter of pipe D _N ^d, standard finished products thickness of pipe S _N ^d, open and to subtract machine inlet frame working diameter φ ₀ ^d, open and to subtract machine outlet frame working diameter φ _N ^d, open and to subtract machine inlet gantry speed v ₀ ^d, standard opens and subtracts machine outlet gantry speed v _N ^d, the effect frame is when being the m frame $v_N^d=v_m^d;$

Step 2 reads the online relevant actual process parameter data that record steel pipe, the online actual wall thickness measured value S that records pipe weight B, tandem rolling length of tube L, the measurement of thickness measurement online instrument _N ^k, each frame current of electric measured value and steel pipe arrive the time of each frame end to end, the inlet gantry speed v of each frame ₀ ^k, outlet gantry speed v _N ^k

And actual tandem rolling external diameter of pipe D is set ₀ ^kWith desirable tandem rolling external diameter of pipe D ₀ ^dUnanimity, promptly $D_0^d=D_0^k;$

Step 3, according to formula: $S_0^k=\frac{D_d-\sqrt{D_d^2-4\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="A20061002852200151.png,A20061002852200161.png"\; state="\{\{state\}\}">C</figure-callout>}}}{2},$ Calculate the actual wall thickness S of current tandem rolling pipe ₀ ^k, wherein: $D_d=D_0^d=D_0^k,$ $C=\frac{(D_0^d-S_0^d)S_0^d{L}_{d}B}{L{B}_d};$

Step 4 by the constancy of volume rule, under the stable rolling state, has for desired quantity and the actual numerical value that records:

$(D_0^d-S_0^d)S_0^d{\mathrm{\&phi;}}_0^d{v}_0^d=(D_N^d-S_N^d)S_N^d{\mathrm{\&phi;}}_N^d{v}_N^d---\left(1\right)$

$(D_0^k-S_0^k)S_0^k{\mathrm{\&phi;}}_0^k{v}_0^k=(D_N^k-S_N^k)S_N^k{\mathrm{\&phi;}}_N^k{v}_N^k---\left(2\right)$

$(D_0^{k+1}-S_0^{k+1})S_0^{k+1}{\mathrm{\&phi;}}_0^{k+1}{v}_0^{k+1}=(D_N^{k+1}-S_N^{k+1})S_N^{k+1}{\mathrm{\&phi;}}_N^{k+1}{v}_N^{k+1}---\left(3\right)$

After rotating speed was adjusted, the variation of roll working diameter was little, can obtain:

${\mathrm{\&phi;}}_0^d\&ap;{\mathrm{\&phi;}}_0^k\&ap;{\mathrm{\&phi;}}_0^{k+1}---\left(4\right)$

${\mathrm{\&phi;}}_N^d\&ap;{\mathrm{\&phi;}}_N^k\&ap;{\mathrm{\&phi;}}_N^{k+1}---\left(5\right)$

The external diameter of steel pipe can be obtained by the pass decision of rolling mill roll:

$D_0^d\&ap;D_0^k\&ap;D_0^{k+1}---\left(6\right)$

$D_N^d\&ap;D_N^k\&ap;D_N^{k+1}---\left(7\right)$

According to formula (1), (2), (3) combination (4), (5), (6), (7), and the wall thickness S that guarantees fished pipe _N ^K+1With target wall thickness S _N ^dUnanimity, promptly $S_N^{k+1}=S_N^d,$ The inlet breast roller rotating speed of wall thickness adaptive control is fed back in the combination that obtains feedovering:

$v_0^{k+1}=\frac{(D_0^d-S_0^k)S_0^k}{(D_0^d-S_0^{k+1})S_0^{k+1}}\frac{(D_N^d-S_N^d)S_N^d}{(D_N^d-S_N^k)S_N^k}{v}_0^k---\left(8\right)$

When wall thickness feed forward is controlled in conjunction with feedback adaptive,, keep the rotating speed of outlet roll constant, promptly in order to guarantee rhythm of production $v_N^d=v_N^k;$ In addition, the finishing frame of back mainly participates in the shaping of steel pipe, can keep their roll rotational speed constant, and only allows tension force rise frame and work housing participation speed governing; If allow m-1 frame participate in speed governing, promptly the rotating speed of m frame is fixed, $v_m^k=v_m^d;$ Can respectively be participated in the breast roller speed of speed governing according to the linear expansion form:

$v_i^{k+1}=v_i^k+\frac{(v_m^d-v_i^d)}{(v_m^d-v_0^d)}(\frac{(D_0^d-S_0^k)S_0^k}{(D_0^d-S_0^{k+1})S_0^{k+1}}\frac{(D_N^d-S_N^d)S_N^d}{(D_N^d-S_N^k)S_N^k}-1)v_0^k---\left(9\right)$

In the formula, v _i ^K+1Expression acts on the speed of rolls of the i frame frame of next root steel pipe, i=1,2...m-1, v _i ^d, v _m ^d, v ₀ ^d, D ₀ ^d, D _N ^d, S _N ^dAll be the value of pass schedule initial setting, S ₀ ^k, S ₀ ^K+1Expression current root tandem rolling wall thickness and next root are wanted the tandem rolling wall thickness of rolled steel tube, S _N ^kSubtract the actual production tube wall thickness of measuring the current root steel pipe that comes of thicknessmeter behind the machine, v according to opening _i ^k, v ₀ ^kRepresent current use when rolling open the speed of rolls that subtracts machine i frame and inlet frame; I frame speed of rolls v from formula (9) pipe that next root will be rolling as can be seen _i ^K+1Be according to current production tube wall thickness S _N ^k, current tandem rolling thickness of pipe S ₀ ^kThe tandem rolling thickness of pipe S that will roll with next root ₀ ^K+1To current i frame speed of rolls v _i ^kWith initial setting i frame speed of rolls v _i ^dComprehensive correction.

For adjusting roll rotational speed following three kinds of situations are arranged:

If one is the actual wall thickness S of production tube _N ^kEqual to decide production tube wall thickness S _N ^d, and current tandem rolling wall thickness S ₀ ^kEqual next root tandem rolling wall thickness S ₀ ^K+1, that is: $S_N^k=S_N^d,$ And $S_0^k=S_0^{k+1},$ Then: $v_i^{k+1}=v_i^k;$ Expression tandem rolling pipe and production tube wall thickness be all during bias free, the value of using when the speed of rolls of rolling next root pipe adopts this rolling.

Its two, this tandem rolling wall thickness and next are wanted rolling tandem rolling wall thickness bias free if the production tube wall thickness has deviation, that is: $S_0^k=S_0^{k+1},$ $\mathrm{\&Delta;S}=S_N^d-S_N^k,$ Formula (9) is equivalent to FEEDBACK CONTROL, formula

(9) can be reduced to:

$v_i^{k+1}=v_i^k+\frac{(v_m^d-v_i^d)}{(v_m^d-v_0^d)}\frac{(D_N^d-S_N^d-S_N^k)}{(D_N^d-S_N^k)S_N^k}{v}_0^k\mathrm{\&Delta;}{S}_N---\left(10\right)$

$\mathrm{\&Delta;}{S}_N=S_N^d-S_N^k$ The difference of having represented current production tube wall thickness and pass schedule setting wall thickness, v _i ^k, v ₀ ^kRepresent current use when rolling open the speed of rolls that subtracts machine i frame and inlet frame; I frame speed of rolls v from formula (10) pipe that next root will be rolling as can be seen _i ^K+1Be according to the production tube wall thickness deviation $\mathrm{\&Delta;}{S}_N=S_N^d-S_N^k$ To current i frame speed of rolls v _i ^kWith initial setting i frame speed of rolls v _i ^dComprehensive correction.

Its three, if production tube wall thickness bias free and this tandem rolling wall thickness and next want rolling tandem rolling wall thickness that deviation be arranged, that is: $S_N^k=S_N^d,$ $\mathrm{\&Delta;S}=S_0^k-S_0^{k+1},$ Formula (9) is equivalent to feedforward control;

It is worthy of note, the currency of this moment is meant the correlation parameter of next above-mentioned root pipe, that is to say and currently want that rolling to open the setting that subtracts the machine speed of rolls be information according to a current tandem rolling wall thickness and a last tandem rolling wall thickness, and a last production tube wall thickness information draws in conjunction with pass schedule initial setting information, therefore, suppose $S_0^d=S_0^{k-1},$ $\mathrm{\&Delta;S}=S_0^k-S_0^{k+1}$ Become $\mathrm{\&Delta;S}=S_0^d-S_0^k,$ Formula (9) is reduced to:

$v_i^k=v_i^d+\frac{(v_m^d-v_i^d)}{(v_m^d-v_0^d)}\frac{(D_0^d-S_0^d-S_0^k)}{(D_0^d-S_0^k)S_0^k}{v}_0^d\mathrm{\&Delta;}{S}_0---\left(11\right)$

$\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="A20061002852200151.png,A20061002852200161.png"\; state="\{\{state\}\}">S</figure-callout>}}_0=S_0^d-S_0^k$ The difference of having represented current tandem rolling wall thickness and last pipe setting wall thickness, S ₀ ^dValue is given; The actual i frame speed of rolls v that will set _i ^kBe according to the tandem rolling wall thickness deviation $\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="A20061002852200151.png,A20061002852200161.png"\; state="\{\{state\}\}">S</figure-callout>}}_0=S_0^d-S_0^k$ I frame speed of rolls v to initial setting _i ^dCorrection.

Step 5 is carried out computing and control to opening the algorithm that subtracts machine on host computer, host computer passes to PLC with signal, controls motor and roll rotational speed by PLC by the parameter of setting;

Step 6 is opened and to be subtracted machine and be rolled the actual value v of the roll rotational speed of the actual achievement collection module real-time collecting steel pipe rolling in the host computer according to the roll rotational speed of setting ₀, v _iEtc. parameter and note.

Embodiment

The stretch reducing process of at first choosing the BRDBY steel pipe of ideal format carries out wall thickness feed forward and controls pilot production in conjunction with feedback adaptive, the parameter of this steel pipe is as follows: waste external diameter of pipe 152.50mm, waste thickness of pipe 6.00mm, production tube external diameter 73.03mm, production tube wall thickness 5.51mm, participate in 18 of rolling machine frames, 12 of rotating speed fixed frames, 12 of control frames;

Because tension force decline frame is the finishing frame, the main effect in rolling is the circularity of regulating steel pipe, therefore, for the control of steel pipe average wall thickness, only allows tension force rise frame and work housing participation steady-state speed adjustment and dynamically rotating speed adjustment.

For specification φ 73.03 * 5.51, in long-term actual production, artificial adjustment by the operative employee, the precision of thickness of steel pipe can reach 73.90%, that is to say, choose a cross section at every steel pipe, the wall thickness of eight points of manual measurement on this cross section, the ratio of wall thickness value in target wall thickness ± 7% error range is 73.90%.

Use stretch reducing mill wall thickness feed forward in conjunction with the feedback adaptive control technology after, carry out manual measurement by the method for the above-mentioned measurement thickness of steel pipe steel pipe that to have chosen 1457 specifications be φ 73.03 * 5.51, the result is shown in table 2 and 3.Can see that from table wall thickness mean value is all in target wall thickness ± 7% error range, the steel pipe number that 8 middle wall thickness maximal values exceed target wall thickness ± 7% is 145, and the steel pipe number that 8 middle wall thickness minimum value exceed target wall thickness ± 7% is 25.Exceed 170 altogether of the steel pipe numbers of target wall thickness ± 7%, accounting for several 1457 11.67%. of total steel pipe also is that the ratio of thickness of steel pipe value in target wall thickness ± 7% error range rises to 88.33%.

Fig. 3, Fig. 4 and Fig. 5 have shown the distribution situation of thickness of steel pipe maximal value, minimum value and mean value respectively.Can see that the wall thickness situation of steel pipe is very desirable.

The Thickness Distribution situation of table 2 steel pipe φ 73.03 * 5.51

	-7% with	-7% to-5%	-5% to-3%	-3% to-1%	-1% to 1%	1% to 3%	3% to 5%	5% to 7%	More than 7%
										Maximal value	0	0	0	0	1	152	584	575	145
Minimum value	25	258	709	406	57	2	0	0	0
										Mean value	0	0	12	312	875	246	11	1	0

The Thickness Distribution ratio of table 3 steel pipe φ 73.03 * 5.51

	Below-7%	-7% to-5%	-5% to-3%	-3% to-1%	-1% to 1%	1% to 3%	3% to 5%	5% to 7%	More than 7%
										Maximal value	0	0	0	0	0.07％	10.43％	40.08％	39.47％	9.95％
Minimum value	1.72％	17.71％	48.66％	27.86％	3.91％	0.14％	0	0	0
										Mean value	0	0	0.82％	21.41％	60.06％	16.88％	0.76％	0.07％	0

Claims (4)

1. stretch reducing mill wall thickness feed forward combination feedback control method, it comprises following steps:

Step 1, read the relevant criterion technological parameter data of steel pipe to be rolled, subtract the relevant criterion technological parameter data of reading steel pipe to be rolled in the pass schedule, standard pipe weight B by opening _d, standard tandem rolling length of tube L _d, standard tandem rolling external diameter of pipe D ₀ ^d, standard tandem rolling thickness of pipe S ₀ ^d, standard finished products external diameter of pipe D _N ^d, standard finished products thickness of pipe S _N ^d, open and to subtract machine inlet frame working diameter φ ₀ ^d, open and to subtract machine outlet frame working diameter φ _N ^d, open and to subtract machine inlet gantry speed v ₀ ^d, standard opens and subtracts machine outlet gantry speed v _N ^d, the effect frame is when being the m frame $v_N^d=v_m^d;$

Step 2, read the online relevant actual process parameter data that record steel pipe, the online actual wall thickness measured value S that pipe weight B, tandem rolling length of tube L, thickness measurement online instrument are measured that records _N ^k, each frame current of electric measured value and steel pipe arrive the time of each frame end to end, the inlet gantry speed v of each frame ₀ ^k, outlet gantry speed v _N ^k

And actual tandem rolling external diameter of pipe D is set ₀ ^kWith desirable tandem rolling external diameter of pipe D ₀ ^dUnanimity, promptly $D_0^d=D_0^k;$

Step 3, according to formula: $S_0^k=\frac{D_d-\sqrt{D_d^2-4C}}{2},$ Calculate the actual wall thickness S of current tandem rolling pipe ₀ ^k, wherein: $D_d=D_0^d=D_0^k,$ $C=\frac{(D_0^d-S_0^d)S_0^d{L}_{d}B}{{\mathrm{LB}}_d};$

Step 4, by the constancy of volume rule, under the stable rolling state, have for desired quantity and the actual numerical value that records:

$(D_0^d-S_0^d)S_0^d{\mathrm{\&phi;}}_0^d{v}_0^d=(D_N^d-S_N^d)S_N^d{\mathrm{\&phi;}}_N^d{v}_N^d---\left(1\right)$

$(D_0^k-S_0^k)S_0^k{\mathrm{\&phi;}}_0^k{v}_0^k=(D_N^k-S_N^k)S_N^k{\mathrm{\&phi;}}_N{v}_N^k---\left(2\right)$

$(D_0^{k+1}-S_0^{k+1})S_0^{k+1}{\mathrm{\&phi;}}_0^{k+1}{v}_0^{k+1}=(D_N^{k+1}-S_N^{k+1})S_N^{k+1}{\mathrm{\&phi;}}_N^{k+1}{v}_N^{k+1}---\left(3\right)$

After rotating speed was adjusted, the variation of roll working diameter was little, can obtain:

${\mathrm{\&phi;}}_0^d\&ap;{\mathrm{\&phi;}}_0^k\&ap;{\mathrm{\&phi;}}_0^{k+1}---\left(4\right)$

${\mathrm{\&phi;}}_N^d\&ap;{\mathrm{\&phi;}}_N^k\&ap;{\mathrm{\&phi;}}_N^{k+1}---\left(5\right)$

The external diameter of steel pipe can be obtained by the pass decision of rolling mill roll:

$D_0^d\&ap;D_0^k\&ap;D_0^{k+1}---\left(6\right)$

$D_N^d\&ap;D_N^k\&ap;D_N^{k+1}---\left(7\right)$

According to formula (1), (2), (3) combination (4), (5), (6), (7), and the wall thickness S that guarantees fished pipe _N ^K+1With target wall thickness S _N ^dUnanimity, promptly $S_N^{k+1}=S_N^d,$ The inlet breast roller rotating speed of wall thickness adaptive control is fed back in the combination that obtains feedovering:

$v_0^{k+1}=\frac{(D_0^d-S_0^k)S_0^k}{(D_0^d-S_0^{k+1})S_0^{k+1}}\frac{(D_N^d-S_N^d)S_N^d}{(D_N^d-S_N^k)S_N^k}{v}_0^k---\left(8\right)$

When wall thickness feed forward is controlled in conjunction with feedback adaptive,, keep the rotating speed of outlet roll constant, promptly in order to guarantee rhythm of production $v_N^d=v_N^k;$ In addition, the finishing frame of back mainly participates in the shaping of steel pipe, can keep their roll rotational speed constant, and only allows tension force rise frame and work housing participation speed governing; If allow m-1 frame participate in speed governing, promptly the rotating speed of m frame is fixed, $v_m^k=v_m^d;$ Can respectively be participated in the breast roller speed of speed governing according to the linear expansion form:

$v_i^{k+1}=v_i^k+\frac{(v_m^d-v_i^d)}{(v_m^d-v_0^d)}(\frac{(D_0^d-S_0^k)S_0^k}{(D_0^d-S_0^{k+1})S_0^{k+1}}\frac{(D_N^d-S_N^d)S_N^d}{(D_N^d-S_N^k)S_N^k}-1)v_0^k---\left(9\right)$

In the formula, v _i ^K+1Expression acts on the speed of rolls of the i frame frame of next root steel pipe, i=1, and 2...m-1,

v _i ^d, v _m ^d, v ₀ ^d, D ₀ ^d, D _N ^d, S _N ^dAll be the value of pass schedule initial setting,

S ₀ ^k, S ₀ ^K+1Expression current root tandem rolling wall thickness and next root are wanted the tandem rolling wall thickness of rolled steel tube,

S _N ^kSubtract the actual production tube wall thickness of measuring the current root steel pipe that comes of thicknessmeter behind the machine according to opening,

v _i ^k, v ₀ ^kY represent current use when rolling open the speed of rolls that subtracts machine i frame and inlet frame;

Step 5 is carried out computing and control to opening the algorithm that subtracts machine on host computer, host computer passes to PLC with signal, controls motor and roll rotational speed by PLC by the parameter of setting;

Step 6 is opened and to be subtracted machine and be rolled the actual value v of the roll rotational speed of the actual achievement collection module real-time collecting steel pipe rolling in the host computer according to the roll rotational speed of setting ₀ ^k, v _i ^kEtc. parameter and note.

2. stretch reducing mill wall thickness feed forward combination feedback control method according to claim 1 is characterized in that: if the actual wall thickness S of production tube _N ^kEqual to decide production tube wall thickness S _N ^d, and current tandem rolling wall thickness S ₀ ^kEqual next root tandem rolling wall thickness S ₀ ^K+1, that is: $S_N^k=S_N^d,$ And $S_0^k=S_0^{k+1},$ Then: $v_i^{k+1}=v_i^k;$ Expression tandem rolling pipe and production tube wall thickness be all during bias free, the value of using when the speed of rolls of rolling next root pipe adopts this rolling.

3. stretch reducing mill wall thickness feed forward combination feedback control method according to claim 1 is characterized in that: this tandem rolling wall thickness is wanted rolling tandem rolling wall thickness bias free with next if the production tube wall thickness has deviation, that is: $S_0^k=S_0^{k+1},$ $\mathrm{\&Delta;S}=S_N^d-S_N^k,$ Formula (9) is equivalent to FEEDBACK CONTROL, and formula (9) can be reduced to:

$v_i^{k+1}=v_i^k+\frac{(v_m^d-v_i^d)}{(v_m^d-v_0^d)}\frac{(D_N^d-S_N^d-S_N^k)}{(D_N^d-S_N^k)S_N^k}{v}_0^k\mathrm{\&Delta;}{S}_N---\left(10\right)$

$\mathrm{\&Delta;}{S}_N=S_N^d-S_N^k$ The difference of having represented current production tube wall thickness and pass schedule setting wall thickness, v _i ^k, v ₀ ^kRepresent current use when rolling open the speed of rolls that subtracts machine i frame and inlet frame; I frame speed of rolls v from formula (10) pipe that next root will be rolling as can be seen _i ^K+1Be according to the production tube wall thickness deviation $\mathrm{\&Delta;}{S}_N=S_N^d-S_N^k$ To current i frame speed of rolls v _i ^kWith initial setting i frame speed of rolls v _i ^dComprehensive correction.

4. stretch reducing mill wall thickness feed forward combination feedback control method according to claim 1 is characterized in that: if production tube wall thickness bias free and this tandem rolling wall thickness and next want rolling tandem rolling wall thickness that deviation be arranged, that is: $S_N^k=S_N^d,$ $\mathrm{\&Delta;S}=S_0^k-S_0^{k+1},$ Formula (9) is equivalent to feedforward control;

It is worthy of note, the currency of this moment is meant the correlation parameter of next above-mentioned root pipe, that is to say and currently want that rolling to open the setting that subtracts the machine speed of rolls be information according to a current tandem rolling wall thickness and a last tandem rolling wall thickness, and a last production tube wall thickness information draws in conjunction with pass schedule initial setting information, therefore, suppose $S_0^d=S_0^{k-1},$ $\mathrm{\&Delta;S}=S_0^k-S_0^{k+1}$ Become $\mathrm{\&Delta;S}=S_0^d-S_0^k,$ Formula (9) is reduced to:

$v_i^k=v_i^d+\frac{(v_m^d-v_i^d)}{(v_m^d-v_0^d)}\frac{(D_0^d-S_0^d-S_0^k)}{(D_0^d-S_0^k)S_0^k}{v}_0^d\mathrm{\&Delta;}{S}_0---\left(11\right)$

$\mathrm{\&Delta;}{S}_0=S_0^d-S_0^k$ The difference of having represented current tandem rolling wall thickness and last pipe setting wall thickness, S ₀ ^dValue is given; The actual i frame speed of rolls v that will set _i ^kBe according to the tandem rolling wall thickness deviation $\mathrm{\&Delta;}{S}_0=S_0^d-S_0^k$ I frame speed of rolls v to initial setting _i ^dCorrection.

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