KR100815815B1 - Method for controlling coating weight on strip in continuous galvanizing process - Google Patents

Abstract

A coating weight controlling method is provided to reduce coating weight deviation on a top end of a strip by setting and learning parameters of a coating weight predicting model in accordance with a target coating weight range, prevent coating weight deviation generated due to variations of the line speed by sensing a change in line speed in a continuous plating process, and reduce coating weight deviation between a surface and a back of the strip by automatically measuring a pass line position in the plating process. A method for controlling coating weight on a strip in a continuous plating process comprises the steps of: calculating set injection pressure values of the injection nozzles using injection pressures of injection nozzles, transfer speed of the strip, and information on position of the injection nozzles to coat the strip in a target coating weight range; setting parameters of a coating weight predicting model in accordance with the transfer speed of the strip, the injection pressures of the injection nozzles, the position of the injection nozzles, and the target coating weight range in the previous step; calculating transfer speed variation of the strip, and changing positions of the injection nozzles; calculating injection pressure values of the injection nozzles and changing a present transfer speed of the strip into a set transfer speed value of the strip if an average distance value between a surface and a back of the strip and the injection nozzles is not greater than a preset reference value; calculating gap variations of the injection nozzles and calculating displacements of the injection nozzles if a pass line moves; calculating skewness values at both sides of a work side and a drive side in the strip width direction if skewness is generated in the strip; calculating horizontal position adjusting amounts of the injection nozzles from the skewness values at both sides; updating the parameters in the coating weight predicting model if a difference between a measured coating weight value of the strip and a target coating weight value set in the coating weight predicting model is not less than a set value after adjusting positions of the injection nozzles as much as the horizontal position adjusting amounts of the injection nozzles; and controlling coating weight in the coating weight predicting model by applying the updated parameters.

Description

METHODS FOR CONTROLLING COATING WEIGHT ON STRIP IN CONTINUOUS GALVANIZING PROCESS}

1 is a schematic configuration diagram of a continuous plating process to which the present invention is applied;

2 is a flowchart showing a plating amount control method according to the present invention;

3 is a view showing the difference in the amount of plating front and back surface of the steel sheet generated when the pass line (pass line) change in the continuous plating process according to the present invention,

4 is an exemplary diagram of an output signal of a rangefinder according to an embodiment of the present invention, and

5 is a view for comparing the filtering of the high frequency signal by the filtering method of the present invention with the filtering of the high frequency signal by the conventional low pass filter.

 Explanation of symbols on the main parts of the drawings

1: sensor value detection unit 2: movement control unit

3a, 3b: Drive motor 4a, 4b, 4c: Distance sensor

5: Feeding speed detecting part 6a, 6b: Plating amount detecting part

7: injection nozzle pressure control valve 8: gas supply source

9: Host computer 10. Plating control amount calculator

11. Nozzle position and pressure control unit 12. Plating bath

13: pressure measuring unit 14a, 14b: injection nozzle

15a, 15b: position detection sensor 17: steel plate

18: molten zinc 19: sink roll

The present invention relates to a method for controlling the plating amount of a steel sheet, and in particular, in the case of plating a steel sheet in a continuous plating process, a continuous plating process of controlling the plating amount of the steel sheet to minimize the plating amount variation (actual plating amount-target plating amount) of zinc adhered to the steel sheet. It relates to a plating amount control method in the.

In general, the surface of the steel sheet is plated to improve the corrosion resistance and the like of the steel sheet. In the process of producing electric steel sheets or automobile steel sheets used for special purposes, such a plating process is a very important work process, and a representative method is a melting process in which zinc is attached to a steel sheet while plating the steel sheet through a bath stored in a molten plating solution. Plating process. In this continuous plating process, the spraying pressure of gas such as air from the spray nozzle (airknife) installed in the vertical direction of the steel sheet passing through the plating bath is adjusted or the gap between the nozzle and the steel sheet is controlled to control the amount of plating attached to the steel sheet. can do.

In the continuous plating process, steel plates having different dimensions are welded to continuously plate the steel plates. Since the target plating amount of the steel sheet varies according to the demand, if the steel grade and the target plating amount change significantly, the injection pressure of the spray nozzle and the distance between the steel sheet and the spray nozzle should be adjusted accordingly. At this time, if the injection pressure or the position control of the injection nozzle is not suitable, the plating amount is less than the target plating amount or excessively plated phenomenon occurs. At this time, in the past, the operator controls the plating amount by varying the injection pressure or the distance of the injection nozzle according to the difference between the plating amount and the target plating amount measured from the plating amount measuring unit installed at a considerable distance from the position of the injection nozzle, so that the control response is slow and empirical. By adjusting the injection pressure or the distance of the injection nozzle, it was impossible to control the precise coating amount. Even if the injection pressure or the distance of the injection nozzle is precisely controlled, even if the plating amount is close to the target plating amount, the plating amount deviation becomes larger when the speed of the line is changed or when the position of the pass line is changed. Will occur.

As an example of the method of controlling the plating amount adhered to a steel plate in the conventional continuous plating process, Unexamined-Japanese-Patent No. 2001-049418 (published on February 20, 2001) discloses the method of controlling the plating amount of a hot dip metal band. In the method disclosed in the above patent, a model equation indicating the relationship between the plating deposition amount and the factors related to the plating deposition amount is set, and the deviation of the plating amount measured from the estimated value calculated from the model and the plating amount measurement is calculated. At this time, since the coating amount measurement is provided at some distance from the nozzle, the estimated value is obtained by reflecting this. The control target plating amount is set on the basis of the obtained deviation, the target pressure corresponding to the control target amount is determined from the above-described model equation, and the pressure is controlled so that the injection pressure becomes the control target pressure. However, this method can only be applied when performing feedback control using the signal measured by the meter in a system with a measurement delay, and the calculation of the model equations related to the coating weight in order to compensate somewhat the instability to the time delay. It can be said that it depends on the degree.

As another example, a method of controlling the amount of plated metal deposition is disclosed in Japanese Unexamined Patent Publication No. 195-268588 (published on October 17, 1995). According to the control method disclosed in the above patent, a plurality of rangefinders are installed on the upper part of the gas injection nozzle, and the distance between the plated steel sheet and the gas injection nozzle is estimated based on the plurality of rangefinder measurements, A method of eliminating the measurement error of the distance between the plated steel plate and the nozzle is provided.

As another example, Japanese Laid-Open Patent Publication No. 1995-180021 (published on July 18, 1995) discloses a nozzle gap control method in a plating facility. The above method relates to a method for preventing the upper and lower plating amount deviations of the steel sheet from occurring when bending in the width direction occurs. The deviation between the upper and lower plating deposition amounts and the target value is checked, and the plating deposition amount deviations between the upper and lower surfaces are checked. It is a method of obtaining and correcting the gap set value of the nozzle based on these deviations. However, since the method controls the gap based on the measured value of the upper and lower surfaces, there is a problem in that the measuring device for measuring the amount of plating deposition is considerably far apart, and thus it is difficult to cope with the deviation if the upper and lower surfaces are quickly removed.

The present invention has been proposed to solve the above-mentioned problems. In the continuous plating process, when there is a change in the target plating amount, the prediction error of the model is reduced in calculating the pressure set value using the estimated value of the model. It is an object of the present invention to provide a plating amount control method for reducing the plating amount deviation (actual plating amount-target plating amount).

In addition, another object of the present invention to provide a plating amount control method that can automatically control the plating amount that can be changed according to the change of the line speed in the continuous plating process.

Further, another object of the present invention is to provide a steel sheet produced by a variation in the amount of plating in the width direction caused by variations in the semi-curvature due to variations in thickness or material of the steel sheet in the continuous plating process or skew of the steel sheet. It is to provide a plating amount control method that can automatically control the deviation in the width direction.

Plating amount control method in a continuous plating process according to the present invention for achieving the above object,

In the continuous plating process of continuously plating the steel sheet, the spray nozzle is sprayed for plating with the target plating amount of the steel sheet by using the spray pressure of the spray nozzles before and after the steel sheet, the feed rate of the steel sheet, and the position information of the spray nozzle. Calculating a pressure set point; Setting parameters of a plating amount prediction model according to the measured feed rate of the steel sheet, the injection pressure of the injection nozzle, the position of the injection nozzle, and the target plating range in the previous time; Changing the position of the injection nozzle to calculate a change in the feed speed of the steel sheet and to adjust the position of the injection nozzle corresponding to the change in the feed speed; If the position of the injection nozzle is changed and the average value of the distance between the front and rear surfaces of the steel sheet and the injection nozzle is equal to or less than the preset reference value, the injection pressure amount of the injection nozzle is calculated, and the current steel sheet feed speed is changed to the feed rate set value of the steel sheet. Doing; Calculating a gap variation of the front and rear injection nozzles of the steel sheet and calculating a movement amount of the front and rear injection nozzles when the pass line is moved; Determining whether the skew occurs in the steel sheet and calculating skew amounts on both the work side and the drive side in the steel plate width direction when skew occurs; Calculating left and right gap injection nozzle position adjustment amounts for removing left and right plating amount deviations in the width direction of the steel sheet from the both skew amounts; After adjusting the position of the injection nozzle by the left and right injection nozzle position adjustment amount, if the difference between the plating amount measurement value of the plated steel sheet and the target plating amount set in the plating amount prediction model is greater than or equal to a set value, the parameters in the plating amount prediction model are determined. Updating; And controlling the plating amount in the plating amount prediction model by applying the updated parameter.

In one embodiment of the present invention, the path line movement and skew generation are determined by using the distance measurement values from the three distance sensors installed in the width direction of the steel sheet.

In one embodiment of the present invention, the step of changing the position of the injection nozzle, calculates the change in the feed rate using the difference between the feed rate measurement value of the steel sheet and the feed rate set value of the steel sheet, In case of 5mpm or more, change the position of injection nozzle.

In the following, a detailed description of a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description of the present invention, in the case where it is determined that detailed descriptions of related well-known functions or configurations may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted so as not to obscure the subject matter of the present invention. will be.

1 is a schematic configuration diagram of a continuous plating process to which the present invention is applied.

Referring to FIG. 1, in the continuous plating process to which the plating amount control method of the present invention is applied, the steel plate 17 in which the heating is completed in the heating furnace enters the plating bath 12 containing the molten zinc 18 and the sink roll 19. And through the straightening roll 20 to move vertically upwards. At this time, the amount of plating adhered to the steel sheet 17 by spraying gas onto the steel sheet 17 exiting the plating bath 12 through the injection nozzles 14a and 14b existing on the front and rear surfaces of the steel sheet 17. Set the target plating amount. Therefore, the injection nozzles 14a and 14b should be applied with a constant injection pressure.

To this end, the host computer 9 transmits the target plating amount and the dimensional information of the steel sheet 17 previously set to the plating control amount calculating unit 10, and the plating control amount calculating unit 10 receives the input target plating amount and the injection pressure detector. Injection pressure detected from 13, injection speed of the steel sheet inputted from the feed rate detector 5 of the steel plate 17, injection received from the position detectors 15a and 15b of the injection nozzles 14a and 14b. Calculate the injection pressure setpoint for the target plating amount of the steel plate 17 using the nozzle position information, and adjust the nozzle pressure control valve 7 according to the nozzle position and the pressure setpoint at the pressure control unit 11 to inject the gas. The pressure of the gas supplied from the source 8 is controlled to control the injection pressure of the injection nozzles 14a and 14b on the front and rear surfaces of the steel plate 17.

In addition, the target plating amount of the steel sheet 17 is controlled by adjusting the distance between the steel plate 17 and the injection nozzles 14a and 14b together with the injection pressure control of the injection nozzles 14a and 14b. To this end, the nozzle position and pressure control unit 11 controls the nozzle position moving motors 16a and 16b by using the injection nozzle position information received from the position detectors 15a and 15b to position the injection nozzles 14a and 14b. Will be adjusted.

In the continuous plating process illustrated in FIG. 1, when the skew of the steel sheet 17 occurs or the pass line is changed, the amount of plating on the front and rear surfaces of the steel sheet 17 may vary. Therefore, it should be detected automatically and reflected in the control. The change of the pass line is a phenomenon that can often occur in the actual process when the thickness or material of the steel sheet is changed. In the present invention, three distance sensors 4a, 4b, 4c are provided at the center and both edge portions of the steel plate 17 vertically rising in the plating bath 12, and the steel plates (4a, 4b, 4c) are separated from the distance sensors 4a, 4b, 4c. 17) and the distance change of the injection nozzles 14a and 14b are measured, and this information is received by the distance value detecting unit 1 and transferred to the plating control amount calculating unit 10. The plating control amount calculating unit 10 measures the pass line movement amount of each point by a predetermined period using the information, and calculates the amount of bending, skew, and pass line movement, respectively. Drive motors 3a and 3b for adjusting the position of the distance sensors 4a, 4b and 4c are provided, and drive motor controllers 2 for controlling the drive motors 3a and 3b are provided. The drive motor control unit 2 operates by receiving the width information of the steel sheet from the plating control amount calculating unit 10.

When the plating is completed, the plating amount measuring units 6a and 6b measure the plating amount attached to the steel plate 17 and feed back the resultant value to the nozzle position and the pressure control unit 11.

2 is a flowchart showing a plating amount control method in a continuous plating process according to the present invention.

Referring to FIG. 2, the plating control amount calculating unit 10 receives the dimensional information and the target plating amount of the steel plate 17 to be plated from the host computer 9, and the injection pressure detector 13 and the steel plate feed rate detector 5. From the injection nozzle position detectors 15a and 15b, the injection pressure of the injection nozzles 14a and 14b, the feed rate of the steel plate 17, and the position information of the injection nozzles 14a and 14b are received (S200). Using Equation 1, the injection pressure set value Pref of the injection nozzles 14a and 14b for plating with the target plating amount of the steel plate 17 is calculated (S202).

Where exp is an exponential function, P is the injection pressure detection value of the injection nozzles 14a and 14b, Cwt1 is the target plating amount of the next steel plate, Cwt0 is the target plating amount of the current steel plate, and c is a parameter of the plating amount prediction model. .

The plating amount prediction model may be represented by Equation 2 below, and Equation 1 may be derived from Equation 2.

Where Cw is the plating amount of the steel plate 17, V is the feed rate of the steel plate 17, G is the distance between the steel plate 17 and the injection nozzles 14a and 14b, and P is the injection pressure of the injection nozzles 14a and 14b. , a, b, and c are parameters of the plating amount prediction model.

Equation 2 shows a relationship between the factors affecting the plating amount of the steel sheet and the plating amount, the factors related to the plating amount is the feed rate (V) of the steel sheet, the distance (G) between the steel sheet and the injection nozzle, the injection pressure of the injection nozzle ( P), and the relationship between the plating amount and these factors has a nonlinear relationship. The amount of plating prediction and control is determined by how accurate the above equation (2) representing the relationship between the target plating amount and these factors is. In addition, since the prediction degree of Equation 2 is also determined according to the setting degree of the parameters a, b, and c, how to determine the parameters a, b, and c is important for the plating amount prediction accuracy. The initial values of the parameters a, b, and c are set in the form shown in Table 1 below according to the target plating amount.

Range of Target Plating parameter a b c Cwt <X A1 B1 C1 Cwt ≥ X A2 B2 C2

Where X, A1, A2, B1, B2, C1, and C2 are constants.

The division of the target plating amount range is a value determined so that the plating amount and the control amount calculated from data such as nozzle gap, steel moving speed, pressure, plating amount measurement and control amount for several months with respect to the target plating amount to be worked. For example, in the case of dividing the target plating range into two categories, the regression parameter for each range is obtained, and the error between the measured value and the calculated value is obtained. The error is obtained by dividing it into three classifications, the error is obtained by dividing N into equal parts, and then, the equal division with the minimum error is selected. The initial value is thus obtained and stored in the table of the plating control amount calculating section 10. The plating control amount calculating unit 10 learns the parameters of the plating amount prediction model using Equation (3).

θ (n) = θ (n-1) + K (n) * (Y _m (n) -Y (n))

Here, θ represents the parameters a, b, and c in Equation 2 as a vector. Θ = [a b c]. n means present value and n-1 means previous value. K denotes the control gain calculated by the sequential least squares algorithm, Ym (k) is the average value of the front and back plating deposition measured from the plating amount measuring sections 6a and 6b for the front and rear surfaces of the steel sheet, and Y (k) is It is a plating amount calculation value computed from Formula (2). That is, it is a value calculated from the measured parameters stored in the transfer speed of the steel sheet, the injection pressure of the injection nozzle, the position of the injection nozzle, and the target plating amount in the previous range and stored.

Subsequently, the feed rate V (k) of the steel plate 17 detected by the moving speed detector 5 of the steel plate 17 and the preset steel plate 17 to check whether the feed speed of the steel plate 17 has been changed. By comparing the feed rate set value (V ₀ ) of the () and calculates the feed rate change amount (ΔV) of the steel plate 17 (S204), the transfer speed change value (△ V) of the steel plate 17 is a predetermined threshold value (For example, 5mpm) or more (S206), the nozzle position and the pressure control unit 11 controls the nozzle position moving motors 16a and 16b so that the nozzles 14a and 14b of the injection nozzles corresponding to the feed rate change amount? In order to adjust the position, the position change command value Sref of the injection nozzles 14a and 14b is calculated by Equation 4 below to adjust the position of the injection nozzle (S208).

Sref = exp (a / bx (log (V (k))-log (V ₀ )) + log (Ga))

Ga = (front jet nozzle position + rear jet nozzle position) / 2

(Where exp is an exponential function, Ga is an average value of the front and rear injection nozzle positions of the steel sheet, V (k) is the current line speed, V ₀ is a reference speed for calculating the speed difference, and a, b Is the parameter in Table 1 above)

If the position of the injection nozzles 14a and 14b is changed so that Ga is less than or equal to a preset reference value (for example, 3 mm) (S210), the position change command value Sref of the injection nozzles 14a and 14b calculated in Equation 3 is calculated. Is set to 0, and the injection pressure amounts of the injection nozzles 14a and 14b are calculated using Equation 5 below (S212).

Pmod = exp (a / cx (log (V ₀ )-log (V (k)) + log (P (k))

(Where exp is the exponential function, a and c are the parameters in Table 1, and P (k) is the injection pressure measurement of the injection nozzle at the present time.)

When the absolute value of the speed change amount exceeds the reference value, the feed rate V (k) of the current steel plate 17 is set to the feed rate set value V ₀ of the steel plate 17 (S214).

Subsequently, the distance measurement signal is read from each distance sensor 4a, 4b, 4c every cycle (S216), and the amount of movement of the pass line is calculated using the resultant value L (k) after filtering the signals. (S218). In the case of the filtering, when a distance sensor having a very high sampling frequency (for example, 1000 Hz or more) is used, it is difficult to design a low pass filter because the sampling frequency is very high. Therefore, when the sample period of the distance sensor is T, n = 1 / T data is output per second. In this case, when n / 4 data is collected, an arithmetic average value of the collected n / 4 data can be output to filter out high frequency fluctuation caused by vibration of the plate.

The resultant value L (k) of filtering the distance measurement signals of the distance sensors 4a, 4b, and 4c and the injection nozzles 14a and 14b before and after the reference were inserted, and the steel plate having a thickness t was inserted. The output values L ₀ of the distance sensors 4a, 4b and 4c are read while the injection nozzles 14a and 14b are moved so that the injection nozzles 14a and 14b engage with the steel plate 17. When the output values of the distance sensors 4a, 4b, and 4c are L ₀ , the movement amount ΔL of the pass line is calculated as in Equation 6 below.

ΔL = L (k)-L ₀ -t / 2

Using ΔL calculated as described above, the gap variation of the front and rear injection nozzles 14a and 14b of the steel sheet 17 is calculated based on Equation 7 below.

△ S _bot = △ L / 2

△ S _top =-△ L / 2

Here, if the sign of DELTA L is negative, the steel plate 17 is moved by DELTA L toward the rear side, and the rear side becomes thinner than the front side. Therefore, the amount of movement of the injection nozzles 14a and 14b on the rear side is away from the steel plate 17, and the front side uses Equation 7 in the direction in which the gap decreases.

Therefore, the movement amounts S _top and S _bot of the front and rear injection nozzles 14a and 14b of the steel plate 17 are calculated using Equation 8 below (S220).

S _top = S _top (k) + △ S _top

S _bot = S _bot (k) + △ S _bot

(S _top (k) and S _bot (k) are the current position measurement of the front and rear injection nozzles.)

Subsequently, when the left and right sides of the steel plate 17 are skewed, that is, when skew occurs, a difference occurs in the amount of plating attached to the left and right in the width direction of the steel plate 17. Measured from the detected values of 4a and 4c, both skew amounts DELTA Lskew on the workside (W / S) and driveside (D / S) sides are calculated using Equation 9 below (S222).

△ Lskew_w / s = Lskew_w / s-Lo_w / s-t / 2

△ Lskew_d / s = Lskew_d / s-Lo_d / s-t / 2

The left and right gap injection nozzle position adjustment amount for removing the left and right plating amount deviation in the width direction of the steel sheet 17 from ΔLskew calculated as described above is calculated using Equation 10 below (S224).

Stop_w / s_ref = Sw / s (k) + (△ Lskew_w / s) / 2

Sbot_w / s_ref = Sd / s (k)-(△ Lskew_d / s) / 2

Stop_d / s_ref = Sw / s (k)-(△ Lskew_w / s) / 2

Sbot_d / s_ref = Sd / s (k) + (△ Lskew_d / s) / 2

While performing the plating process through this process, the plating amount measuring unit (6a, 6b) to measure the coating amount of the front and rear of the steel plate 17, and when the plating amount measurement is completed (S226), the front of the steel plate 17 If the difference is smaller than the set value (X) by calculating a difference in the amount of back plating (S228) and comparing the calculated value of the amount of coating on the front and back surface with the value (X) set in the plating amount prediction model (S230). Each parameter in the plating amount prediction model is updated (S232).

As described above, when the position of the pass line is changed in the continuous plating process as shown in FIG. 3, the amount of plating on the front surface and the amount of plating on the rear surface may be varied. In other words, when the steel sheet pass line moves in the rear direction, the plating amount on the back side decreases and the plating amount on the front side becomes large. In addition, the feed rate of the steel sheet is changed in accordance with the change of the dimensions or the change of the material by the situation of the heating furnace to control the temperature of the steel sheet to control the material of the steel sheet, and if the speed of the steel sheet changes in this way, the plating amount is also changed. In order for the plating amount to be close to the target plating amount, the plating amount deviation should not occur when the target plating amount of the steel plate is changed by accurately calculating the setting amount according to the change of the target plating amount.If the position change or bending of the pass line occurs, Even if the line speed is changed, the plating amount can be controlled quickly.

The present invention provides a control method that can automatically control the plating amount variation that may occur in accordance with the change of the target plating amount, the change of the pass line, and the change of the line speed.

4 is a graph of an output signal of a distance sensor according to an exemplary embodiment of the present invention, and FIG. 5 compares filtering of a high frequency signal component by a filtering method of the present invention with filtering of a high frequency signal component by a conventional low pass filter. It is a figure for illustrative description.

Referring to FIG. 4, a graph shows a result of actually measuring a moving amount of a steel sheet at a sample frequency of 1000 Hz using a laser distance sensor, and shows a result of performing an arithmetic mean of 250 data collected each time. 5 is a graph comparing the filtering effect in the present invention and the prior art with respect to the movement amount data of the steel sheet measured in FIG. FIG. 5A illustrates a case where the filtering method of the present invention is applied, and FIG. 5B illustrates a case where a conventional low pass filter of 0.01 Hz is applied. 5 (a) can be seen to be superior in terms of the filtering effect than (b).

The drawings and detailed description of the invention are merely exemplary of the invention, which are used for the purpose of illustrating the invention only and are not intended to limit the scope of the invention as defined in the appended claims or claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

According to the plating amount control method of the present invention described above, since the parameters of the plating amount predictive model are set and learned according to the target plating amount range, the accuracy of the predictive model can be increased, and the setting accuracy of the gap or pressure due to the change of the target value is increased frequently. It is possible to quickly control the change in the target plating amount to reduce the variation in the plating amount of the tip.

In addition, according to the present invention it is possible to detect the change in the line speed in the continuous plating process to automatically change the pressure and gap for this, thereby preventing the variation in the plating amount due to the line speed variation.

Furthermore, according to the present invention, by measuring the pass line position in the plating process automatically detects the change of the pass line according to the thickness or material, the change of the position of the nozzle or the change of the position of the calibration roll and the resulting It is possible to reduce the variation in plating amount on the front and back.

Claims (3)

In the continuous plating process of continuously plating the steel sheet, the spray pressure of the spray nozzle for plating the target plating amount of the steel sheet using the spray pressure of the spray nozzles on the front and rear of the steel sheet, the conveying speed of the steel sheet, and the position information of the spray nozzle. Calculating a setpoint; Setting parameters of a plating amount prediction model according to the measured feed rate of the steel sheet, the injection pressure of the injection nozzle, the position of the injection nozzle, and the target plating range in the previous time; Changing the position of the injection nozzle to calculate a change in the feed speed of the steel sheet and to adjust the position of the injection nozzle corresponding to the change in the feed speed; If the position of the injection nozzle is changed and the average value of the distance between the front and rear surfaces of the steel sheet and the injection nozzle is equal to or less than the preset reference value, the injection pressure amount of the injection nozzle is calculated, and the current steel sheet feed speed is changed to the feed rate set value of the steel sheet. Doing; Calculating a gap variation of the front and rear injection nozzles of the steel sheet and calculating a movement amount of the front and rear injection nozzles when the pass line is moved; Determining whether the skew occurs in the steel sheet and calculating skew amounts on both the work side and the drive side in the steel plate width direction when skew occurs; Calculating left and right gap injection nozzle position adjustment amounts for removing left and right plating amount deviations in the width direction of the steel sheet from the both skew amounts; After adjusting the position of the injection nozzle by the left and right injection nozzle position adjustment amount, if the difference between the plating amount measurement value of the plated steel sheet and the target degree gold amount set in the plating amount prediction model is greater than or equal to a set value, the parameter in the plating amount prediction model Updating them; And Controlling the plating amount in the plating amount prediction model by applying the updated parameter; Plating amount control method in a continuous plating process comprising a. The method of claim 1, A method for controlling the plating amount in a continuous plating process, characterized in that the pass line movement and skew generation are determined by using distance measurement values from three distance sensors provided in the width direction of the steel sheet. The method of claim 1, wherein the changing of the position of the injection nozzle comprises: Continuous plating is characterized in that the feed rate change amount is calculated using the difference between the feed rate measurement value of the steel plate and the feed rate set value of the steel plate, and the position of the spray nozzle is changed when the feed rate change amount is equal to or more than a preset value. How to control the plating amount in the process.

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