CN104785543A - Hot rolled strip convexity feedback control method based on moving average filter - Google Patents

Abstract

The invention relates to a hot rolled strip convexity feedback control method based on moving average filter. Moving average filter processing is performed on an actual convexity value detected at a finish rolling F7 rack outlet; the tendency variation of the convexity is extracted and the roll bending force of a rack F1 to a rack F4 is dynamically adjusted at the front four racks from F1 to F4 of F7 rack hot continuous rolling finish rolling according to the deviation between the actual convexity obtained by moving average filter processing and the target convexity; the tendency of the convexity variation is controlled to be eliminated through the convexity feedback, and the cyclical fluctuation is compensated and eliminated through the roll force. According to the hot rolled strip convexity feedback control method based on the moving average filter, the control overshoot and instability caused by the convexity fluctuation and convexity feedback large lag caused by the temperature fluctuation can be avoided, the overall convexity control precision in the length direction can be improved, and the problem that the overall convexity control precision is low due to the fact that mistuning or overshooting is prone to occurring in a traditional convexity control method can be solved.

Description

A kind of hot-strip crown feedback control method based on moving average filter

Technical field

The present invention relates to hot-strip production technical field, be specifically related to a kind of hot-strip crown feedback control method based on moving average filter.

Background technology

Plate shape weighs one of most important index of strip product quality, and weighing the common two indices of plate shape quality is strip crown and glacing flatness.Strip crown, also known as band steel lateral thickness difference, refers to Strip thickness difference in the width direction.Different hot-strip products, also different to the requirement of strip crown, the requirement of hot-tandem unit to the control of strip crown is ensureing under the condition that finish rolling outlet band steel is straight, by Crown control to desired value.

In hot continuous rolling production process, the principal element affecting strip profile has roll machinery convexity, the convexity change that roller heat convex degree learning, roll wear convexity and band steel lateral flow cause.The convexity change that the body of roll change in shape that the roll that factor mainly contains the original convexity of roll, roll-force causes bends and elastic flattening and Strip Shape Control mechanism position as traversing in CVC, the set amount at PC angle and bending roller force set-point cause affecting roll machinery convexity is brought.Wherein, roll-force is the principal element of influence zone steel total length convexity change, rolls' deformation changes along with the change of roll-force, thus strip profile is changed, and the principal element of influence of rolled power is exactly temperature, variations in temperature directly causes roll-force to change, thus influence zone steel exports convexity.The convexity that roller heat convex degree learning, roll wear convexity and band steel lateral flow cause is physical process, and general device condition is constant, and in same steel mill process, these values remain unchanged.

The early stage major control means of Crown control of hot-strip are setup controls, its principle is the rolling data (roll-force of each frame of the current band steel calculated according to finishing stand setup calculation procedure (FSU), contact arc length, each rack outlet thickness etc.), PDI data (target width, thickness, target convexity, glacing flatness), and the roll data (diameter of working roll and backing roll that roller management application program provides, convexity, barrel length etc.), each road sub-band steel roll thermal crown that roll thermal crown computing module calculates, the wearing and tearing convexity data of each road sub-band steel that roll wear computing module provides, the current PC angle transmitted from L1 and roller force value, the rolls' deformation of each frame and each rack outlet convexity is calculated with a series of model, thus the setting value calculating the Strip Shape Control mechanism of each frame (optimizes bending roller force, PC angle or the traversing position of CVC), ensure that band steel reaches Target Board convexity and flatness requirements.But, hot continuous rolling Strip Shape Control be a multivariable, time become, close coupling and nonlinear complex process, various plate shape influence factor in the operation of rolling, as roll-force, bending roller force, roll wear, roll thermal crown etc. all can change along with time course and locus, and interact, be coupled.According to formed bits for mill roller and band steel theory of plastic strain in matrix, mathematical relationship between various plate shape factor and final roll gap is quite complicated, therefore the Mathematical Modeling in current plat control system is all based upon on a large amount of simplification and hypothesis basis, and result of calculation often can not be met consumers' demand and Product Precision.Although introduce adaptation mechanism, self adaptation only works to follow-up band steel, once deviation appears in setting, would not have any correction, cause strip profile entirety overproof in the whole operation of rolling of current strip profile.

Owing to adopting merely setup control convexity to have above-mentioned shortcoming, Dynamic controlling was introduced in the Crown control of hot continuous rolling in the last few years, to reduce the convexity deviation that model specification is forbidden to bring, improved hot-strip total length convexity and led to plate difference precision.Current dynamic control method mainly contains two kinds: one is that roll-force compensates, namely first a roll-force is locked, the deviation of the actual roll-force that then basis detects in the operation of rolling and locking roll-force, the bending roller force of each frame of dynamic conditioning exports, and makes the convexity of each rack outlet keep fixed value.Another kind is crown feedback, according to being arranged on convexity actual value that finish rolling end frame multi-functional instrument below detects and desired value compares, convexity deviation is converted into the correction value of each frame bending roller force, FEEDBACK CONTROL is carried out to convexity, because afer bay band steel flakiness ratio is very large, the rolling of equal proportion convexity must be kept, otherwise easily produce shape wave defect, so general crown feedback generally only works to the bending roller force of forebay.

Main at present exist following several hot-continuous-rolling strip steel crown feedback control technology:

(1) 2010 year 07 month 20 days disclosed patent No.s of application are the patent of invention " convexity of hot rolled in series type rolling machine and/or wedge shape autocontrol method and system " of 201010230419.8, this invention relates to a kind of convexity of hot rolled in series type rolling machine and/or wedge shape autocontrol method and system (ASCC), by setting up from first to the working roller bending of last platform finishing stand and the FEEDBACK CONTROL of roll gap leveling in hot rolled in series type rolling machine, achieve full-automatic band convexity (wedge shape) to control, namely in the operation of rolling, ASCC model is after detecting band gad shape, compare deviate with target wedge shape, the comprehensive computing of system and control device is utilized to rectify a deviation, set up staged method of adjustment, thus the response of FEEDBACK CONTROL is maximized, to correct band gad shape and convexity, ensure the glacing flatness that product is good, prevent the serpentine locomotion of band steel in each frame, eliminate the drawback that existing Crown control means are single, the overall balance relation of convexity and glacing flatness.This patent can carry out Comprehensive Control to wedge shape and convexity, but do not carry out any process to along strip length direction convex value, because multi-functional instrument distance executing agency (each frame bending roller force) is distant, exist larger delayed, when convexity fluctuation is larger, overshoot can be caused and even oppositely regulate, the fluctuation of mm finishing mill unit outlet convexity can be strengthened.

(2) patent No. of 06 month 09 day nineteen ninety-five application is the patent of invention " STRIPPROFILE CONTROL " of WO1995GB01354, this patent is by measuring three frame tandem mills outlet convexity deviations, then according to the water yield of this drift correction frame cooling water thus the outlet convexity of control cincture steel carries out feedback regulation to outlet convexity.The method can improve strip profile control accuracy.But this mode does not carry out any filtering process to convex measuring value equally, measured value directly applies to FEEDBACK CONTROL, be difficult to control the convexity fluctuation of the various upper frequencies occurred in the operation of rolling, due to the delayed of measuring instrument and the large dead time of water-cool control convexity, mistuning is also easily caused to save in some cases.

These methods improve Crown control precision mainly through FEEDBACK CONTROL above, but due to be positioned at for the measuring instrument of FEEDBACK CONTROL finish rolling outlet frame after, there is larger time stickiness, can only be used for control tendency change convexity; And current method all processes convex measuring value, can not elimination temperature or supplied materials convexity to fluctuate the convexity cyclically-varying caused, extract the tendency change of convexity, so easily there is mistuning or overshoot in actual use, affect whole Crown control precision.

Summary of the invention

The object of this invention is to provide a kind of hot-strip crown feedback control method based on moving average filter, the method utilizes the method elimination of glide filter to fluctuate the convexity cyclic fluctuation caused due to temperature or roll-force, only FEEDBACK CONTROL is carried out to the tendency deviation of convexity, avoid overshoot or oppositely regulate, improve the convexity precision of hot-strip product, mistuning or overshoot is easily there is, the problem that whole Crown control precision is low in order to solve traditional convex degree control method.

For achieving the above object, the solution of the present invention is: a kind of hot-strip crown feedback control method based on moving average filter, the method is applied to 7 frame hot-rolling finishing mills, Crown control equipment comprises multi-functional instrument, crown feedback controller and process machine, described multi-functional instrument is arranged on finish rolling F7 rack outlet, described multi-functional instrument is connected with the signal input part of crown feedback controller with the signal output part of process machine, the control output end of described crown feedback controller is connected with finish rolling F1 ~ F4 frame, and the method comprises the steps:

(1) according to beam distance and the band steel threading speed of water-cooling beam of heating furnace, the filtering cycle of finish rolling F7 rack outlet moving average filter is obtained;

(2) the convexity desired value of process machine setting band steel, and send crown feedback controller to;

(3) when band steel threading completes, and after the multi-functional instrument of head arrival finish rolling outlet, multi-functional instrument starts to measure strip profile, and sends the strip profile measured value measured to crown feedback controller;

(4) if the hits of crown feedback controller to convexity measured value is less than the moving average filter cycle, then the bending roller force of finish rolling F1 ~ F4 frame remains unchanged; If the hits of convexity measured value is more than or equal to the moving average filter cycle, then moving average filter process is carried out to the convexity measured value of sampling;

(5) compare the convexity measured value after moving average filter process and convexity desired value, obtain convexity deviate, and convexity deviate is assigned to finish rolling F1 ~ F4 frame;

(6) the convexity deviate of each rack outlet in finish rolling F1 ~ F4 frame is converted into bending roller force correction value, the bending roller force correction value of described each frame is carried out PI adjustment;

(7) the bending roller force correction value after being regulated by PI carries out amplitude limiting processing, that is: if the bending roller force correction value after PI adjustment exceeds its limiting value, then bending roller force correction value exports as limiting value, if do not go beyond the limit of value, then exports the bending roller force correction value that step (6) obtains;

(8) bending roller force correction value step (7) obtained superposes with the current roller force value of F1 ~ F4 frame, obtains new roller force value;

(9) finish rolling F1 ~ F4 frame is exported to after amplitude limit being carried out to new roller force value, regulate the bending roller force of F1 ~ F4 frame, complete the Crown control to hot-strip one-period, and start the new cycle, until after tail part of band steel leaves F1 frame, complete and control the crown feedback of whole band steel.

In described step (1), the filtering cycle of moving average filter is:

$S_e=\frac{t_e}{T_c}$

Wherein, S _efor the glide filter cycle;

T _efor the rolling time that the slab length band steel that is water-cooling beam of heating furnace beam distance exports in finish rolling;

T _cfor the sampling period of crown feedback.

Described slab length is the rolling time that the band steel of water-cooling beam of heating furnace beam distance exports in finish rolling:

$t_e=\frac{l_e}{v_e\·(1+f_e)}\·G_v;$

Wherein, t _efor the rolling time that the slab length band steel that is water-cooling beam of heating furnace beam distance exports in finish rolling;

L _efor the distance that the slab length band steel that is water-cooling beam of heating furnace beam distance exports to finish rolling;

V _efor finish rolling outlet threading speed;

F _efor finish rolling exports advancing slip value;

G _vfor speed regulation coefficient.

Described slab length is the distance that the band steel of water-cooling beam of heating furnace beam distance exports to finish rolling:

$l_e=\frac{H_s\·W_s\·L_r}{h_e\·w_e}$

Wherein, l _efor the distance that the slab length band steel that is water-cooling beam of heating furnace beam distance exports to finish rolling;

H _sfor the slab thickness in heating furnace;

W _sfor the width of plate slab in heating furnace;

L _rwater-cooling beam of heating furnace beam distance;

H _efor finish rolling outlet belt steel thickness;

W _efinish rolling outlet strip width.

In described step (4), the method for the convexity measured value of sampling being carried out to moving average filter process is: the S of continuous sampling _eindividual convexity measured value regards a queue as, and the length of queue is fixed as S _e, sample a new convexity measured value at every turn and put into tail of the queue, and throw away a convexity measured value of original head of the queue, the S in queue _eindividual convexity measured value carries out arithmetic average computing, just can obtain new filter result.

In described step (5), the convexity measured value after moving average filter process is:

${\mathrm{Cf}}_k=\frac{{\mathrm{\Σ}}_{j=k-S_e}^k{C}_j}{S_e}$

Wherein, Cf _kfor the convexity measured value of a kth cycle after glide filter process;

Cj: a jth cycle original convexity measured value;

S _efor the glide filter cycle.

In described step (5), method convexity deviation being assigned to finish rolling F1 ~ F4 frame is:

First, convexity deviation is assigned to each frame of F1 ~ F4, described convexity deviation is:

Δcm _i=ccm _i·(cf _j-c ₀)

Wherein, Δ cm _ifor being assigned to the convexity deviation of the i-th frame, i=1,2,3,4; ccm _ibeing the convexity distribution coefficient of the i-th frame, is a constant relevant with description; Cfj is the convexity measured value of jth cycle after glide filter process; C ₀for convexity desired value;

Then, according to the ratio convexity principle of correspondence, the convexity of finish rolling F7 rack outlet is converted into the convexity correction value of finish rolling F1-F4 rack outlet, that is:

$\mathrm{\Δ}{\mathrm{cs}}_i={\mathrm{Gcm}}_i\·\mathrm{\Δ}{\mathrm{cm}}_i\·\frac{h_i}{h_7}$

Wherein, Δ CS _ibe the i-th rack outlet convexity correction value, i=1,2,3,4; Gcm _ibeing the gain coefficient of the i-th frame convexity correction value, concerning each frame, is a fixed value, i=1,2,3,4; h _ibe the i-th rack outlet thickness, i=1,2,3,4; h ₇be the 7th rack outlet thickness.

In described step (6), bending roller force correction value is:

$\mathrm{\Δ}{\mathrm{fbc}}_i=\frac{\mathrm{\Δ}{\mathrm{cs}}_i}{{\mathrm{Gef}}_i}$

Wherein, Δ fbc _iit is total correction of the i-th frame bending roller force;

Gef _ibe that the i-th frame bending roller force is to the gain coefficient of convexity;

Δ Cs _iit is the i-th rack outlet convexity correction value;

i=1,2,3,4。

In described step (6), the method for bending roller force correction value being carried out to PI adjustment is:

ΔFbp _(i,j)=Δfbc _i·Gp _i

ΔFbI _(i,j)=Δfbc _i·GI _i·T _c+ΔFbI _(i,j-1)

Δfb _(i,j)=ΔFbp _(i,j)+ΔFbI _(i,j)

Wherein, Δ Fbp _{(i, j)}it is the ratio retouch of the i-th frame jth cycle bending roller force correction value;

Δ FbI _{(i, j)}it is the integration retouch of the i-th frame jth cycle bending roller force correction value;

Δ fb (i, j) is the total correction of the i-th frame jth cycle bending roller force;

Gp _iit is the proportional control gain of the i-th frame;

GI _iit is the integration control gain of the i-th frame;

Δ fbc _iit is total correction of the i-th frame bending roller force;

Tc is the control cycle of Crown control;

i=1,2,3,4。

In described step (8), new roller force value is:

fb _(i,j)=fb _s+Δfb _(i,j)

Wherein, fb _{(i, j)}for new roller force value;

Fb _sfor the initial value of bending roller force;

Δ fb _{(i, j)}it is the total correction value of the i-th frame jth cycle bending roller force;

i=1,2,3,4；j=1～S _e。

The beneficial effect that the present invention reaches: convex degree control method of the present invention compensates roll-force and crown feedback has done rational division of work, moving average filter process is carried out by the convexity actual value detected finish rolling end rack outlet, in front four frames of seven frame hot continuous rolling finish rolling, according to the deviation of the actual convexity after moving average filter process and target convexity, extract the tendency change of convexity, dynamically F1-F4 bending roller force is regulated, control by crown feedback the trend eliminating convexity change, and cyclic fluctuation compensates elimination by roll-force.The control overshoot that the large time delay avoiding convexity fluctuation that temperature fluctuation causes and crown feedback causes and unstability, improve length direction entirety convexity control accuracy.

Accompanying drawing explanation

Fig. 1 is the theory diagram of the crown feedback control device that the present invention adopts;

Fig. 2 is the schematic flow sheet that crown feedback of the present invention controls;

Fig. 3 is the schematic diagram of moving average filter of the present invention;

Fig. 4 is the crown feedback control effects schematic diagram adopting glide filter in application example of the present invention;

Fig. 5 be in application example of the present invention after moving average filter process convexity measured value;

Fig. 6 is that in application example of the present invention, each frame bending roller force controls output valve;

Fig. 7 is traditional crown feedback control effects schematic diagram in application example of the present invention;

Fig. 8 is that in application example of the present invention, traditional crown feedback controls each frame bending roller force control output valve.

Detailed description of the invention

Below in conjunction with accompanying drawing, the present invention is further detailed explanation.

As Fig. 1,1 ~ 7 is finishing stand F1 ~ F7, and 8 is multi-functional instrument, and 10 ~ 15 is kink.The crown control device that the present invention adopts comprises multi-functional instrument, crown feedback controller and process machine, described multi-functional instrument is arranged on finish rolling F7 rack outlet, described multi-functional instrument is connected with the signal input part of crown feedback controller with the signal output part of process machine, and the control output end of described crown feedback controller is connected with finish rolling F1 ~ F4 frame.

The course of work of this control device is as follows: when band steel threading completes, after head arrives the multi-functional instrument after F7 frame, the convexity measured value of multi-functional instrument measuring tape steel, multi-functional instrument sends the convexity measured value measured to crown feedback controller.After crown feedback controller receives convexity measured value, moving average filter process is carried out to the convexity measured value received.Convexity measured value after process and comparing from the convexity desired value that process machine transmits, calculate a deviation, then through the calculating of a series of Mathematical Modeling, in conjunction with the thickness of each passage belonged to from process machine and bending roller force to data such as the gains of convexity, calculate the correction value eliminating this each frame bending roller force of F1-F4 needed for convexity deviation.The correction value of this bending roller force is added in current roller force value, gives bending roller force executing agency namely: each frame of F1-F4, then starts next control cycle, until tail part of band steel leaves F1 frame.

As Fig. 2, crown feedback control method of the present invention comprises the steps:

(1) according to beam distance and the band steel threading speed of water-cooling beam of heating furnace, the filtering cycle of finish rolling F7 rack outlet moving average filter is obtained;

(2) the convexity desired value of process machine setting band steel, and send crown feedback controller to;

(3) when band steel threading completes, and after the multi-functional instrument of head arrival finish rolling outlet, multi-functional instrument starts to measure strip profile, and sends the strip profile measured value measured to crown feedback controller;

(4) if the hits of crown feedback controller to convexity measured value is less than the moving average filter cycle, then the bending roller force of finish rolling F1 ~ F4 frame remains unchanged; If the hits of convexity measured value is more than or equal to the moving average filter cycle, then moving average filter process is carried out to the convexity measured value of sampling;

(5) compare the convexity measured value after moving average filter process and convexity desired value, obtain convexity deviate, and convexity deviate is assigned to finish rolling F1 ~ F4 frame;

(6) the convexity deviate of each rack outlet in finish rolling F1 ~ F4 frame is converted into bending roller force correction value, the bending roller force correction value of described each frame is carried out PI adjustment;

(7) the bending roller force correction value after being regulated by PI carries out amplitude limiting processing, that is: if the bending roller force correction value after PI adjustment exceeds its limiting value, then bending roller force correction value exports as limiting value, if do not go beyond the limit of value, then exports the bending roller force correction value that step (6) obtains;

(8) bending roller force correction value step (7) obtained superposes with the current roller force value of F1 ~ F4 frame, obtains new roller force value;

(9) finish rolling F1 ~ F4 frame is exported to after amplitude limit being carried out to new roller force value, regulate the bending roller force of F1 ~ F4 frame, complete the Crown control to hot-strip one-period, and start the new cycle, until after tail part of band steel leaves F1 frame, complete and control the crown feedback of whole band steel.

Hot-continuous-rolling strip steel is when afer bay F5-F7, and general thickness is very thin, if regulated bending roller force in the operation of rolling, easily produces shape wave defect, so the crown feedback of hot continuous rolling generally regulates convexity with the bending roller force of forebay F1-F4.Because nearest frame distance convex measuring instrument is also very far away, exist larger delayed, the advantage so this with the hot continuous rolling Crown control technology of glide filter is just only to control the overall offset trend of convexity, avoids convexity and to fluctuate the overshoot that causes or mistuning joint.

The detailed process implementing the inventive method is as follows:

(1) the filtering cycle of moving average filter is calculated

The convexity fluctuation of hot continuous rolling finish rolling outlet, mostly because roll-force fluctuation produces, and the fluctuation of roll-force to be temperature fluctuation cause, temperature fluctuation mainly comes from the watermark point that heating of plate blank process produces, and is because the step rate of heating furnace causes.Therefore, in order to extract convexity variation tendency, the convexity change that temperature causes must be filtered, and the cycle of the convexity change that variations in temperature causes is on all four with watermark point.What we adopted is the method for glide filter, therefore, first according to the beam distance of water-cooling beam of heating furnace, must calculate the filtering cycle exporting glide filter at F7.

First, computational length is the distance that heating furnace beam exports apart from slab to finish rolling:

$l_e=\frac{H_s\·W_s\·L_r}{h_e\·w_e}$

In above formula, l _efor the distance that the slab length band steel that is water-cooling beam of heating furnace beam distance exports to finish rolling; H _sfor the slab thickness in heating furnace; W _sfor the width of plate slab in heating furnace; L _rwater-cooling beam of heating furnace beam distance; h _efor finish rolling outlet belt steel thickness; w _efor finish rolling outlet strip width.

Then, the rolling time that this length band steel exports in finish rolling is calculated:

$t_e=\frac{l_e}{v_e\·(1+f_e)}\·G_v;$

In above formula, t _efor the rolling time that the slab length band steel that is water-cooling beam of heating furnace beam distance exports in finish rolling; l _efor the distance that the slab length band steel that is water-cooling beam of heating furnace beam distance exports to finish rolling; v _efor finish rolling outlet threading speed; f _efor finish rolling exports advancing slip value; G _vfor speed regulation coefficient.

Finally, the filtering cycle of moving average filter is obtained:

$S_e=\frac{t_e}{T_c}$

In above formula, S _efor the glide filter cycle; t _efor the rolling time that the slab length band steel that is water-cooling beam of heating furnace beam distance exports in finish rolling; T _cfor the sampling period of crown feedback.

(2) moving average filter process is carried out to the convexity measured value measured

Moving average filter is also called recurrence average filter method, belongs to the one of low pass filter, and its advantage has good inhibitory action to PERIODIC INTERFERENCE, and smoothness is high, is applicable to the system of the higher-order of oscillation; Shortcoming is that sensitivity is low, poor to the inhibitory action of the pulse feature interference accidentally occurred, not easily eliminates the sampled value deviation caused by impulse disturbances, is not suitable for the occasion that impulse disturbances is more serious.

The convexity change of hot-continuous-rolling strip steel finish rolling outlet can be decomposed into two parts: a part is the periodic convexity fluctuation because variations in temperature produces, and is a kind of high-frequency signal; Another part is the tendency change of convexity, and convexity is overall higher or on the low side, is a kind of low frequency signal of slow change.Seldom there is unexpected acute variation in convexity, so adopt moving average filter, can filter because the temperature fluctuation periodicity convexity that particularly watermark point causes fluctuates, the trend extracting convexity change controls.

The implementation method of moving average filter regards a queue as getting N number of sampled value continuously, the length of queue is fixed as N, sample a new data at every turn and put into tail of the queue, and throw away a secondary data of original head of the queue, N number of data in queue are carried out arithmetic average computing, just can obtain new filter result.Specific to the moving average filter of convexity of finishing mill outlet actual measurement, as long as the convexity cyclic fluctuation that the temperature fluctuation that watermark point causes because convexity adopts the object of glide filter to filter causes, so the filtering periodic quantity S that N is exactly previous step to be calculated _e.

As shown in Figure 3, the S calculated is supposed _eequal 6, when taking the lead multi-functional instrument position after finish rolling on earth, after multi-functional instrument measures first convexity data, time delay a period of time to accumulate the convexity data needed for glide filter, delay duration must be more than or equal to t _evalue.When strip profile hits is greater than S _eafter, start glide filter and calculate, first group of strip profile value Cf after glide filter ₆just equal to comprise current sample values C ₆the mean value of the first six convexity data, that is: next convexity measured value C ₇after collecting, jettisoning sequence first data C ₁, then calculate current sample values C ₇before push away 6 number C ₂~ C ₇mean value, with post processing data by that analogy, concrete formula is as follows:

${\mathrm{Cf}}_k=\frac{{\mathrm{\Σ}}_{j=k-S_e}^k{C}_j}{S_e}$

Wherein, Cf _kfor the convexity measured value of a kth cycle after glide filter process;

Cj: a jth cycle original convexity measured value;

S _efor the glide filter cycle.

(3) convexity deviation is assigned to each frame

Convex measuring value after moving average filter process and the deviation of desired value are the deviations after F7, and the executing agency of crown feedback is F1-F4 frame, so the convexity deviation measured must be assigned to each frame.

First, convexity deviation is assigned to each frame of F1 ~ F4, the convexity deviation being assigned to each frame is:

Δcm _i=ccm _i·(cf _j-c ₀)

Wherein, Δ cm _ifor being assigned to the convexity deviation of the i-th frame, i=1,2,3,4; ccm _ibeing the convexity distribution coefficient of the i-th frame, is a constant relevant with description; Cfj is the convexity measured value of jth cycle after glide filter process; C ₀for convexity desired value;

Then, according to the ratio convexity principle of correspondence, the convexity of finish rolling F7 rack outlet is converted into the convexity correction value of finish rolling F1-F4 rack outlet, that is:

$\mathrm{\Δ}{\mathrm{cs}}_i={\mathrm{Gcm}}_i\·\mathrm{\Δ}{\mathrm{cm}}_i\·\frac{h_i}{h_7}$

Wherein, Δ Csi is the i-th rack outlet convexity correction value, i=1,2,3,4; Gcmi is the gain coefficient of the i-th frame convexity correction value, concerning each frame, is a fixed value, i=1,2,3,4; Hi is the i-th rack outlet thickness, i=1,2,3,4; h ₇be the 7th rack outlet thickness.

(4) regulated quantity that each rack outlet convexity deviation is converted into bending roller force is exported to executing agency F1 ~ F4 frame

In hot rolling process, the deviation of convexity can only be revised by the change of bending roller force, and therefore, the convexity deviation of each rack outlet that must first previous step be calculated is converted into the correction of bending roller force, that is:

$\mathrm{\Δ}{\mathrm{fbc}}_i=\frac{\mathrm{\Δ}{\mathrm{cs}}_i}{{\mathrm{Gef}}_i}$

Wherein, Δ fbc _iit is total correction of the i-th frame bending roller force; Gef _ibe that the i-th frame bending roller force is to the gain coefficient of convexity; Δ Cs _iit is the i-th rack outlet convexity correction value; I=1,2,3,4.

Directly giving executing agency by bending roller force correction value can cause system oscillation, causes convexity to fluctuate on the contrary, therefore will carry out PI adjustment by a PI controller to bending roller force correction value, to reduce system fluctuation, improves control accuracy.The process that PI regulates is:

ΔFbp _(i,j)=Δfbc _i·Gp _i

ΔFbI _(i,j)=Δfbc _i·GI _i·T _c+ΔFbI _(i,j-1)

Δfb _(i,j)=ΔFbp _(i,j)+ΔFbI _(i,j)

Wherein, Δ Fbp _{(i, j)}it is the ratio retouch of the i-th frame jth cycle bending roller force correction value; Δ FbI _{(i, j)}it is the integration retouch of the i-th frame jth cycle bending roller force correction value; Δ fb (i, j) is the total correction of the i-th frame jth cycle bending roller force; Gp _iit is the proportional control gain of the i-th frame; GI _iit is the integration control gain of the i-th frame; Δ fbc _iit is total correction of the i-th frame bending roller force; Tc is the control cycle of Crown control; I=1,2,3,4.

The correction value of each control cycle each frame bending roller force and the total output valve of bending roller force need to carry out amplitude limit, if current bending roller force correction value is greater than the amplitude limit value upper limit, then bending roller force correction value just equals the amplitude limit value upper limit; If if current bending roller force correction value is less than amplitude limit value lower limit, then bending roller force correction value just equals amplitude limit value lower limit.Total bending roller force exports also to be needed to carry out bound inspection, and bound is respectively the bending roller force bound that each frame plant equipment allows, and when total bending roller force is greater than higher limit, then total bending roller force just equals higher limit.When total bending roller force is less than lower limit, then total bending roller force just equals lower limit.

Introduce an embody rule example of the present invention below:

The present invention applies in certain factory 1580 course of hot rolling machine transformation project plat control system, and the relevant parameter used in concrete enforcement is as follows:

Step rate beam is apart from L _r=1.1m

Speed regulation coefficient G _v=1.2

F1 ~ F4 each frame convexity distribution coefficient ccm _ibe worth as shown in table 1:

Table 1

Frame	F1	F2	F3	F4
					ccm i	0.3	0.3	0.3	0.1

The gain coefficient Gcm of F1 ~ F4 each frame convexity correction value _ibe worth as shown in table 2:

Table 2

Frame	F1	F2	F3	F4
					Gcm i	0.15	0.15	0.15	0.1

The proportional control gain Gp of each frame of F1 ~ F4 _ibe worth as shown in table 3:

Table 3

Frame	F1	F2	F3	F4
					Gp i	0.4	0.4	0.35	0.2

The integration control gain GI of each frame of F1 ~ F4 _ibe worth as shown in table 4:

Table 4

Frame	F1	F2	F3	F4
					GI i	0.35	0.35	0.3	0.25

The control cycle T of Crown control _c=1.0s.

One-step control amplitude limit value is as shown in table 5:

Table 5

One-step control amplitude limit (KN)	F1	F2	F3	F4
					The upper limit	900	900	900	700
Lower limit	-400	-400	-400	-400

Total bending roller force amplitude limit value is as shown in table 6:

Table 6

Total bending roller force amplitude limit (KN)	F1	F2	F3	F4
					The upper limit	1200	1200	1200	900
Lower limit	-1200	100	100	100

The specification of rolled band steel: slab specification: thickness H _s=230mm width W _s=1150mm, hot-strip trimmed size finish rolling exit thickness h _e=2.32mm, finish rolling exit width w _e=1050mm, target convexity C ₀=40 _μm.The bending roller force that process machine calculates is to the gain coefficient Gef of convexity _ivalue is as table 7:

Table 7

Frame	F1	F2	F3	F4
					Gef i	-191643	-180439	-153281	-96651.4

Fig. 4 ~ Fig. 6 is the crown feedback control effects adopting moving average filter, and Fig. 7, Fig. 8 are the effects that same batch of band steel adopts traditional crown feedback to control.Fig. 5 is through the finish rolling outlet convexity measured value of moving average filter process, Fig. 5 and Fig. 4 contrasts known: filtered convexity measured value medium-high frequency wave portion in Fig. 5, only remains the trend of convexity change.Comparison diagram 7 and Fig. 4 can find out, the crown feedback based on moving average filter controls more traditional crown feedback and controls more steady, and overshoot is little, and convexity fluctuating range obviously reduces.Fig. 6 and Fig. 8 controls based on the crown feedback of moving average filter and the regulation output of bending roller force of each frame of traditional crown feedback control, contrast as can be seen from figure, the crown feedback of moving average filter is adopted to export steadily, and traditional Crown control output pulsation is large, and there is larger overshoot.

As can be seen from this application example, adopt the crown feedback of moving average filter to control more traditional crown feedback and control more level and smooth, overshoot is few, and convexity fluctuation is less.The present invention adopts moving average filter to control after the process of convexity measured value, more traditional crown feedback technology effectively can reduce the delayed control hyperharmonic mistuning brought of system, control more steady, precision is higher, has promotional value widely in hot continuous rolling field.

The quality index that convexity Shi Ge hot continuous rolling factory is important.The present invention is intended to utilize a kind of crown feedback control method based on glide filter, eliminates the convexity caused due to the temperature fluctuation crown feedback caused that fluctuates and controls overshoot and unstability, improve the convexity precision of band steel total length.Specifically in front four frames of seven frame hot continuous rolling finish rolling, the actual convexity detected according to last rack outlet and the deviation of target convexity, dynamically regulate F1-F4 bending roller force, and convexity deviation being eliminated is zero.Main feature is the band steel obvious for band steel total length watermark point, temperature fluctuation is larger, to actual measurement to the convexity convexity fluctuation that adopts the mode of glide filter to eliminate temperature fluctuation to cause, extract the change of total length convexity tendency, only FEEDBACK CONTROL is carried out to the tendency change of convexity, the cyclic fluctuation of convexity is then solved by roll-force force compensating, the control overshoot that the large time delay avoiding convexity fluctuation that temperature fluctuation causes and crown feedback causes and unstability.

Claims (10)

1. the hot-strip crown feedback control method based on moving average filter, the method is applied to 7 frame hot-rolling finishing mills, Crown control equipment comprises multi-functional instrument, crown feedback controller and process machine, described multi-functional instrument is arranged on finish rolling F7 rack outlet, described multi-functional instrument is connected with the signal input part of crown feedback controller with the signal output part of process machine, the control output end of described crown feedback controller is connected with finish rolling F1 ~ F4 frame, it is characterized in that: the method comprises the steps:

(1) according to beam distance and the band steel threading speed of water-cooling beam of heating furnace, the filtering cycle of finish rolling F7 rack outlet moving average filter is obtained;

(2) the convexity desired value of process machine setting band steel, and send crown feedback controller to;

(3) when band steel threading completes, and after the multi-functional instrument of head arrival finish rolling outlet, multi-functional instrument starts to measure strip profile, and sends the strip profile measured value measured to crown feedback controller;

(4) if the hits of crown feedback controller to convexity measured value is less than the moving average filter cycle, then the bending roller force of finish rolling F1 ~ F4 frame remains unchanged, and continues the convexity measured value that sampling multi-functional instrument is measured; If the hits of convexity measured value is more than or equal to the moving average filter cycle, then moving average filter process is carried out to the convexity measured value of sampling;

(5) compare the convexity measured value after moving average filter process and convexity desired value, obtain convexity deviate, and convexity deviate is assigned to finish rolling F1 ~ F4 frame;

(6) the convexity deviate of each rack outlet in finish rolling F1 ~ F4 frame is converted into bending roller force correction value, the bending roller force correction value of described each frame is carried out PI adjustment;

(7) the bending roller force correction value after being regulated by PI carries out amplitude limit, that is: if the bending roller force correction value after PI adjustment exceeds its limiting value, then bending roller force correction value exports as limiting value, if do not go beyond the limit of value, then exports the bending roller force correction value that step (6) obtains;

(8) bending roller force correction value step (7) obtained superposes with the current roller force value of F1 ~ F4 frame, obtains new roller force value;

(9) finish rolling F1 ~ F4 frame is exported to after amplitude limit being carried out to new roller force value, regulate the bending roller force of F1 ~ F4 frame, complete the Crown control to hot-strip one-period, and start the new cycle, until after tail part of band steel leaves F1 frame, complete and control the crown feedback of whole band steel.

2. the hot-strip crown feedback control method based on moving average filter according to claim 1, is characterized in that, in described step (1), the filtering cycle of moving average filter is:

$S_e=\frac{t_e}{T_c}$

Wherein, S _efor the glide filter cycle;

T _efor the rolling time that the slab length band steel that is water-cooling beam of heating furnace beam distance exports in finish rolling;

T _cfor the sampling period of crown feedback.

3. the hot-strip crown feedback control method based on moving average filter according to claim 2, is characterized in that described slab length is the rolling time that the band steel of water-cooling beam of heating furnace beam distance exports in finish rolling and is:

$t_e=\frac{l_e}{v_e\·(1+f_e)}\·G_v;$

Wherein, t _efor the rolling time that the slab length band steel that is water-cooling beam of heating furnace beam distance exports in finish rolling;

L _efor the distance that the slab length band steel that is water-cooling beam of heating furnace beam distance exports to finish rolling;

V _efor finish rolling outlet threading speed;

F _efor finish rolling exports advancing slip value;

G _vfor speed regulation coefficient.

4. the hot-strip crown feedback control method based on moving average filter according to claim 3, is characterized in that described slab length is the distance that the band steel of water-cooling beam of heating furnace beam distance exports to finish rolling and is:

$l_e=\frac{H_s\·W_s\·L_r}{h_e\·w_e}$

Wherein, l _efor the distance that the slab length band steel that is water-cooling beam of heating furnace beam distance exports to finish rolling;

H _sfor the slab thickness in heating furnace;

W _sfor the width of plate slab in heating furnace;

L _rwater-cooling beam of heating furnace beam distance;

H _efor finish rolling outlet belt steel thickness;

W _efor finish rolling outlet strip width.

5. the hot-strip crown feedback control method based on moving average filter according to claim 2, is characterized in that in described step (4), and the method for the convexity measured value of sampling being carried out to moving average filter process is: the S of continuous sampling _eindividual convexity measured value regards a queue as, and the length of queue is fixed as S _e, sample a new convexity measured value at every turn and put into tail of the queue, and throw away a convexity measured value of original head of the queue, the S in queue _eindividual convexity measured value carries out arithmetic average computing, just can obtain new filter result.

6. the hot-strip crown feedback control method based on moving average filter according to claim 5, is characterized in that in described step (5), the convexity measured value after moving average filter process is:

${\mathrm{Cf}}_k=\frac{{\mathrm{\Σ}}_{j=k-S_e}^k{C}_j}{S_e}$

Wherein, Cf _kfor the convexity measured value of a kth cycle after glide filter process;

Cj: a jth cycle original convexity measured value;

S _efor the glide filter cycle.

7. the hot-strip crown feedback control method based on moving average filter according to claim 1, is characterized in that in described step (5), method convexity deviation being assigned to finish rolling F1 ~ F4 frame is:

First, convexity deviation is assigned to each frame of F1 ~ F4, described convexity deviation is:

Δcm _i=ccm _i·(cf _j-c ₀)

Wherein, Δ cm _ifor being assigned to the convexity deviation of the i-th frame, i=1,2,3,4; ccm _ibeing the convexity distribution coefficient of the i-th frame, is a constant relevant with description; Cfj is the convexity measured value of jth cycle after glide filter process; C ₀for convexity desired value;

Then, according to the ratio convexity principle of correspondence, the convexity of finish rolling F7 rack outlet is converted into the convexity correction value of finish rolling F1-F4 rack outlet, that is:

$\mathrm{\Δ}{\mathrm{cs}}_i={\mathrm{Gcm}}_i\·\mathrm{\Δ}{\mathrm{cm}}_i\·\frac{h_i}{h_7}$

Wherein, Δ Csi is the i-th rack outlet convexity correction value, i=1,2,3,4; Gcmi is the gain coefficient of the i-th frame convexity correction value, concerning each frame, is a fixed value, i=1,2,3,4; Hi is the i-th rack outlet thickness, i=1,2,3,4; h ₇be the 7th rack outlet thickness.

8. the hot-strip crown feedback control method based on moving average filter according to claim 1, is characterized in that in described step (6), bending roller force correction value is:

$\mathrm{\Δ}{\mathrm{fbc}}_i=\frac{\mathrm{\Δ}{\mathrm{cs}}_i}{{\mathrm{Gef}}_i}$

Wherein, Δ fbc _iit is total correction of the i-th frame bending roller force;

Gef _ibe that the i-th frame bending roller force is to the gain coefficient of convexity;

Δ Cs _iit is the i-th rack outlet convexity correction value;

i=1,2,3,4。

9. the hot-strip crown feedback control method based on moving average filter according to claim 1, is characterized in that in described step (6), the method for bending roller force correction value being carried out to PI adjustment is:

ΔFbp _(i,j)=Δfbc _i·Gp _i

ΔFbI _(i,j)=Δfbc _i·GI _i·T _c+ΔFbI _(i,j-1)

Δfb _(i,j)=ΔFbp _(i,j)+ΔFbI _(i,j)

Wherein, Δ Fbp _{(i, j)}it is the ratio retouch of the i-th frame jth cycle bending roller force correction value;

Δ FbI _{(i, j)}it is the integration retouch of the i-th frame jth cycle bending roller force correction value;

Δ fb (i, j) is the total correction of the i-th frame jth cycle bending roller force;

Gp _iit is the proportional control gain of the i-th frame;

GI _iit is the integration control gain of the i-th frame;

Δ fbc _iit is total correction of the i-th frame bending roller force;

Tc is the control cycle of Crown control;

i=1,2,3,4。

10. the hot-strip crown feedback control method based on moving average filter according to claim 1, is characterized in that in described step (8), new roller force value is:

fb _(i,j)=fb _s+Δfb _(i,j)

Wherein, fb _{(i, j)}for new roller force value;

Fb _sfor the initial value of bending roller force;

Δ fb _{(i, j)}it is the total correction value of the i-th frame jth cycle bending roller force;

i=1,2,3,4；j=1～S _e。