JP2006103066A - Control unit of sheet manufacturing apparatus, sheet manufacturing apparatus, control method of sheet manufacturing apparatus and program executed by computer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the control unit of a sheet manufacturing apparatus capable of performing control of high precision even in a case that a plant gain is varied between actuators approaching each other by the mutual interference of operation quantity. <P>SOLUTION: The control unit 19 of the sheet manufacturing apparatus is equipped with a space frequency calculation means for calculating the deviation between the thickness values corresponding to the respective operation points of a plurality of thickness adjusting means to extract the deviation between the thickness values of a predetermined range centering around the respective operation points and subsequently applying frequency conversion to calculate the space frequency component in the width direction of the deviation between the thickness values, a representative frequency calculation means for calculating representative from the space frequency component, a gain correction factor calculation means for calculating a gain correction factor on reference to characteristic data which preliminarily stores the relation between the representative frequency and the gain correction factor on the basis of the representative frequency calculated by the representative frequency calculation means and a gain correction means for multiplying the gain correction factor by the control gain of each of the operation points. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control apparatus for a sheet manufacturing apparatus, a sheet manufacturing apparatus, a control method for a sheet manufacturing apparatus, and a program to be executed by a computer, and more specifically, a control apparatus for a sheet manufacturing apparatus that controls the thickness of a sheet, The present invention relates to a sheet manufacturing apparatus, a control method for the sheet manufacturing apparatus, and a program executed by a computer.

  2. Description of the Related Art Conventionally, a sheet such as a film is manufactured by extruding a molten resin from an elongated lip (base) and stretching it, and then winding the sheet into a roll with a winder.

  The thickness of the sheet member pulled out from the lip of the die is measured at a plurality of locations in the width direction, the average of the measured thickness values measured in the width direction is obtained, and this average thickness value becomes the sheet target thickness. The sheet thickness of the sheet-shaped member is controlled, the lower limit of the allowable thickness value and the upper limit of the allowable thickness value are set so as to be within a predetermined allowable range with respect to the average thickness value. Estimate the height of the aneurysm that occurs in the take-up machine, and if the estimated height of the aneurysm is positive, the thickness allowable lower limit is set as the target value. A thickness control method in a sheet-like member manufacturing facility is known in which the lip opening degree adjusting actuator is controlled so as to achieve a target value (Patent Document 1).

  Further, in a roll sheet manufacturing method in which a molten resin is extruded from a lip into a sheet shape, and the sheet is stretched and wound into a roll-shaped original fabric, a mechanical adjustment mechanism for adjusting the gap between the lips, and melting of the lip tip When controlling the sheet thickness using a temperature adjusting mechanism for adjusting the temperature of the resin, a thickness meter for measuring the thickness of the sheet after stretching, a shape measuring means for measuring the outer shape of the original fabric shape, or a shape calculating means for predicting. The thickness unevenness which eliminates the deviation between the sheet thickness unevenness based on the information of the thickness gauge and the target value by using the mechanical adjustment mechanism until the sheet thickness unevenness falls within the predetermined value range from the start of manufacture of the sheet. After that, the temperature adjustment mechanism is used to eliminate the deviation between the original shape deviation based on the information of the shape measuring means or the shape calculating means and its target value. Rolled sheet manufacturing method of switching the control to perform the raw shape deviation control is known (see Patent Document 2).

JP-A-5-309717 JP 2002-283438 A

  However, in the above prior art, the opening degree and gap of the lip are adjusted using a plurality of mechanically coupled actuators, but the plant gain (actuator of the actuator) is caused by the mutual interference of the operation amount between the adjacent actuators. Control is not performed in consideration of the fluctuation of the influence amount of the operation amount on the thickness value.

  That is, when the operation amount to the adjacent actuator is in the same direction, the plant gain increases due to the mutual interference of the operation amount, and when the operation amount is in the reverse direction, the plant gain decreases. In the above conventional technique, gain compensation is not performed in accordance with the fluctuation of the plant gain, and therefore there is a problem that high-precision control cannot be performed when the plan gain fluctuates.

  The present invention has been made in view of the above, and a control device for a sheet manufacturing apparatus capable of performing high-precision control even when a plant gain fluctuates due to mutual interference of operation amounts between adjacent actuators. An object of the present invention is to provide a sheet manufacturing apparatus, a control method for the sheet manufacturing apparatus, and a program to be executed by a computer.

  In order to solve the above-described problems and achieve the object of the present invention, according to the control device of the sheet manufacturing apparatus according to the present invention, a lip for discharging molten resin in a sheet form, the lip provided, In a sheet manufacturing apparatus comprising a plurality of thickness adjusting means for adjusting the thickness of the resin and a thickness measuring means for measuring the thickness of the sheet-like resin discharged from the lip in the width direction, the thickness measuring means measures the thickness. A control device of the sheet manufacturing apparatus that controls the operation amount of the plurality of thickness adjusting means so that the thickness in the width direction of the resin becomes a target value based on the measurement result of the thickness in the width direction of the resin. Deviation calculating means for calculating a deviation of the thickness value corresponding to each operation point of the plurality of thickness adjusting means based on the measurement result of the thickness in the width direction of the resin measured by the thickness measuring means. , Out of the thickness value deviations calculated by the deviation calculating means, after extracting the thickness value deviation within a predetermined range centered on each operation point, the frequency conversion is performed, and the width direction space of the thickness value deviation is obtained. Spatial frequency component calculating means for calculating a frequency component, representative frequency calculating means for calculating a representative frequency from the spatial frequency component, and representative frequency and gain correction coefficient based on the representative frequency calculated by the representative frequency calculating means in advance. A gain correction coefficient calculation means for calculating a gain correction coefficient, and a gain correction means for multiplying the control gain of each operation point by the gain correction coefficient. Features.

  In the present invention, the control gain is compensated so that the mutual interference of the operation amounts of the plurality of mechanically coupled actuators can be obtained as the spatial frequency of the control amount, and the fluctuation of the plant gain is canceled. Yes. That is, the spatial frequency component calculating unit calculates a deviation of the thickness value corresponding to each operation point of the plurality of thickness adjusting units based on the measurement result of the thickness in the width direction measured by the thickness measuring unit. After extracting the deviation of the thickness value within a predetermined range with the operation point as the center, frequency conversion is performed to calculate the spatial frequency component in the width direction of the deviation of the thickness value, and the representative frequency calculating means is configured to represent the representative frequency from the spatial frequency component. The gain correction coefficient calculation means calculates the gain correction coefficient based on the representative frequency calculated by the representative frequency calculation means with reference to characteristic data in which the relationship between the representative frequency and the gain correction coefficient is stored in advance. The gain correction means multiplies the control gain at each operation point by a gain correction coefficient. In this way, when the plant gain increases, the gain correction coefficient is decreased, while when the plant gain decreases, the gain correction coefficient is increased, and the gain compensation is performed according to the variation of the plant gain. Even when the plant gain fluctuates due to the mutual interference of the operation amount between the actuators to be operated, high-precision control is performed.

  Further, according to the control device for a sheet manufacturing apparatus according to the present invention, the deviation calculating means calculates a deviation from an arbitrarily set value of the thickness value corresponding to each operation point of the plurality of thickness adjusting means. It is characterized by. Thereby, the deviation of the thickness value is easily calculated with high accuracy.

  Further, according to the control device for a sheet manufacturing apparatus according to the present invention, the spatial frequency component calculation means performs a window function process after extracting a deviation from a thickness value within a predetermined range centering on each operation point, and thereafter The frequency conversion is performed. As a result, unnecessary data is removed, and high-precision and high-speed computation is possible.

  Further, according to the control device of the sheet manufacturing apparatus according to the present invention, the frequency conversion is a Fourier transform. Thereby, the spatial frequency component in the width direction of the deviation from the thickness value can be calculated with a simple calculation.

  Further, according to the control apparatus for a sheet manufacturing apparatus according to the present invention, the representative frequency calculation means calculates a center-of-gravity value, an average value, or a center value of the spatial frequency component as the representative frequency. To do. Thereby, the frequency representing the distribution of the spatial frequency components is determined easily and with high accuracy.

  In addition, according to the sheet manufacturing apparatus of the present invention, the control apparatus for the sheet manufacturing apparatus described above is mounted. Thereby, even when the plant gain fluctuates due to the mutual interference of the operation amount between adjacent actuators, it is possible to perform highly accurate control and make the thickness in the width direction of the sheet uniform.

  In order to solve the above-described problems and achieve the object of the present invention, according to the control method of the sheet manufacturing apparatus according to the present invention, a lip for discharging molten resin in a sheet form, the lip provided, A plurality of thickness adjusting means for adjusting the thickness of the resin, and a thickness measuring means for measuring the thickness of the sheet-like resin discharged from the lip at each operation point of the plurality of thickness adjusting means in the width direction. In the sheet manufacturing apparatus, based on the thickness of the resin measured by the thickness measuring unit, the sheet manufacturing for controlling the operation amount of the plurality of thickness adjusting units so that the thickness in the width direction of the resin becomes a target value. A method for controlling an apparatus, wherein a deviation of a thickness value corresponding to each operation point of the plurality of thickness adjusting means is calculated based on a measurement result of the thickness in the width direction of the resin measured by the thickness measuring means. Out of the deviation calculation step and the deviation of the thickness value calculated in the deviation calculation step, after extracting the deviation of the thickness value within a predetermined range centering on each of the operation points, frequency conversion is performed to calculate the thickness value Based on the spatial frequency component calculating step for calculating the spatial frequency component in the width direction of the deviation, the representative frequency calculating step for calculating the representative frequency from the spatial frequency component, and the representative frequency calculated in the representative frequency calculating step in advance. A gain correction coefficient calculating step of calculating a gain correction coefficient with reference to characteristic data storing a relationship between a representative frequency and a gain correction coefficient; and a gain correction step of multiplying the control gain of each operation point by the gain correction coefficient; , Including.

  According to the control method of the sheet manufacturing apparatus of the present invention, in the deviation calculating step, the deviation from an arbitrarily set value of the thickness value corresponding to each operation point of the plurality of thickness adjusting means is calculated. It is characterized by. Thereby, the deviation of the thickness value is easily calculated with high accuracy.

  Further, according to the control method of the sheet manufacturing apparatus according to the present invention, in the spatial frequency component calculation step, the window function process is performed after extracting the deviation of the thickness value within a predetermined range centering on each of the operation points, and thereafter It is characterized by performing frequency conversion.

  According to the control method of the sheet manufacturing apparatus of the present invention, the frequency conversion is a discrete Fourier transform.

  Further, according to the method for controlling a sheet manufacturing apparatus according to the present invention, in the representative frequency calculation step, the center frequency value, the average value, or the center value of the spatial frequency distribution is calculated as the representative frequency. To do.

  Further, according to a program to be executed by a computer according to the present invention, the computer is caused to execute each step of the above-described sheet manufacturing apparatus control method. Thereby, the control method of the above-mentioned sheet manufacturing apparatus is realizable using a computer.

  As described above, according to the present invention, by performing gain compensation in accordance with the fluctuation of the plant gain, even when the plant gain fluctuates due to the mutual interference of the operation amount between the adjacent actuators, high-precision control is achieved. Can be performed.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  FIG. 1 is a diagram illustrating a configuration of a sheet manufacturing apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the sheet manufacturing apparatus 1 includes a stretching machine 12, an extruder 13, a base 14, a cooling roll 15, a winder 16, a transport roll 17, a thickness gauge 18, and a control device 19.

  The extruder 13 is charged with resin that has been heated and melted. A base 14 is connected to the extruder 13. The base 14 has a long slit, and the molten resin is cooled by a cooling roll 15 and solidified. The sheet-like resin is transported through the transport roll 17 and stretched by the stretching machine 12. The thickness of the sheet 11 coming out from the stretching machine 12 is measured by a thickness gauge 18. Thereafter, the sheet is conveyed through a conveyance roll 17 and wound up by a winder 16.

  The thickness gauge 18 is connected to the control device 19 and transmits a signal indicating the measured sheet thickness to the control device 19. The thickness gauge 18 may be either a contact type or a non-contact type, but a non-contact type is preferable because there is little risk of damaging the sheet 11. Examples of the non-contact type thickness gauge include a light absorption type utilizing β rays, ultraviolet rays, infrared rays, etc. in addition to the optical interference type. The thickness meter 18 can measure the thickness of an arbitrary position in the width direction of the sheet 11. The control device 19 includes gain compensation means and target value calculation means, and is connected to the thickness gauge 18 and the base 14, and based on a signal indicating the thickness of the sheet 11 input from the thickness gauge 18, the thickness adjustment means 20. To control.

  FIG. 2 is a diagram showing the configuration of the base 14. The base 14 includes a thickness adjusting means 20 arranged in a large number in the longitudinal direction of the slit. This thickness adjusting means 20 is connected to the control device 19 and adjusts the thickness of the sheet 11 coming out of the slit 21 by a signal from the control device 19.

  As a means for adjusting the thickness of the sheet 11 coming out of the slit 21, a bolt material that pushes and pulls the slit with a screw, a heater built in the inside, and the expansion of the slit by controlling the thermal expansion according to the heating amount of the heater are provided. There is a heat bolt that pulls. Or it is also possible to adjust the thickness of the sheet | seat 11 using that the resin flow volume increases when a part of slit 21 is heated.

  FIG. 3 is a flow for explaining the control of the control device 19. The flow of FIG. 3 includes operations of the gain compensation means 30 and the target value calculation means 40. In FIG. 3, the thickness gauge 18 measures the thickness in the width direction of the sheet, and sends a signal indicating the measured thickness to the control device 19 (S1).

  The control device 19 sets a target value r for the sheet thickness (S2). The control device 19 calculates a thickness measurement value t [i] corresponding to each operation point of the thickness adjusting means 20 (S3). Here, i represents a discrete coordinate value in the width direction of the sheet, and i = 1 to N (N is an integer of 2 or more).

  Next, the control device 19 calculates a control deviation e [i] = t [i] −r of the thickness value (S4). Based on the control deviation e [i], the control device 19 calculates the operation amount u of the thickness adjusting unit 20 using PID control or the like (S5), and outputs the operation amount u to the thickness adjusting unit 20 (S6).

  Further, the control device 19 calculates a thickness measurement value t [i] corresponding to each operation point of the thickness adjusting means 20 (S7). Here, i represents a discrete coordinate value in the width direction of the sheet, and i = 1 to N (N is an integer of 2 or more).

  The control device 19 calculates the average thickness ta in the width direction of the sheet based on the thickness measurement value t [i] at each operation point (S8). Next, a deviation ex [i] = t [i] -ta from the average thickness value of each operation point is calculated (S9). Here, the deviation from the average of the thickness values is calculated, but the deviation from the average is not limited, and the deviation from an arbitrarily set value may be calculated.

  The control device 19 cuts out deviations ex [i−x] to ex [i + x] from the average of the thickness values in a predetermined range centered on the deviation ex [i] from the average thickness value corresponding to each operation point ( S10). For example, when i = 5 and X = 4, [ex1, ex2, ex3, ex4, ex5, ex6, ex7, ex8, ex9]. If there is no corresponding operation point, “0” is substituted. For example, when i = 4 and X = 4, [0, ex1, ex2, ex3, ex4, ex5, ex6, ex7, ex8] are obtained.

  The control device 19 processes the deviations ex [i−x] to ex [i + x] from the average of the cut out thickness values with the window function W (u), and then performs frequency conversion to obtain a space for the deviation from the average of the thickness values. A frequency component is calculated (S11). As the window function W (u), for example, various window functions such as the Hanning window and the Blackman window shown in the following formula (1) can be used.

  As the frequency conversion, Fourier transform X (jω) shown in the following equation (2) can be used. Note that the frequency conversion is not limited to Fourier transform, and other frequency conversion may be used.

  The control device 19 calculates the representative frequency f1 of the spatial frequency component of the deviation from the average thickness value (S12). For example, as the representative frequency f1, the centroid value, average value, or center value of the spatial frequency component can be used.

  The control device 19 calculates the gain correction coefficient C from the gain correction coefficient table based on the representative frequency f1 (S13). The control device 19 multiplies the control gain by the gain correction coefficient C (S14). The operation amount u multiplied by the gain correction coefficient C is output to the thickness adjusting unit 20. Thereby, since the control gain is multiplied by the gain correction coefficient C corresponding to the variation of the plant gain, the gain compensation is performed so as to cancel the variation of the plant gain. Specifically, when the plant gain increases, the gain correction coefficient is decreased, while when the plant gain decreases, the gain correction coefficient is increased.

  FIG. 4 is a diagram illustrating an example of the gain correction coefficient table. The gain correction coefficient table is obtained by calculating a gain correction coefficient C suitable for each representative frequency f1 by experiment and tabulating characteristic data indicating the relationship between the representative frequency f1 and the gain correction coefficient C. Here, the gain correction coefficient table is used. However, characteristic data indicating the relationship between each representative frequency f1 and a suitable gain correction coefficient C is stored as an arithmetic expression, and the gain is calculated using the arithmetic expression. The correction coefficient C may be calculated. The process of the above step S1-step S14 is repeated for every control period.

  FIG. 5 is a diagram illustrating the configuration of the control device 19. The control device 19 includes a target value calculation unit 40, a subtracter 41, a proportional control unit 42, an integration control unit 43, an adder 44, and a gain compensation unit 30.

  The target value calculation means 40 calculates a target value r. The subtracter 41 subtracts the target value r from the thickness y sent from the thickness gauge 18 and outputs it as a control deviation e. Based on the control deviation e, the proportional control unit 42 and the integral control unit 43 each calculate an operation amount. The adder 44 adds the operation amounts of the proportional control unit 42 and the integration control unit 43.

  The actuator 45 is controlled based on the added operation amount u. The actuator 45 controls the thickness adjusting means 20 to change the thickness of the sheet. The result is sent to the thickness gauge 18, and the measurement result of the thickness gauge 18 is output to the subtractor 41.

  On the other hand, the gain compensation means 30 includes a frequency component calculation unit 31, a representative frequency calculation unit 32, a gain correction coefficient calculation unit 33, a gain correction coefficient table 34, and a variable multiplier 35.

  The frequency component calculation unit 31 is based on the thickness value y sent from the thickness gauge 18, and the deviation ex from the average of thickness values in a predetermined range centered on the deviation ex [i] of the thickness value y corresponding to each operation point. After cutting out [i−x] to ex [i + x] and processing with the window function W (u), the spatial frequency component of the deviation of the thickness in the width direction is calculated by frequency conversion.

  The representative frequency calculation unit 32 calculates the representative frequency f1 of the spatial frequency component of the deviation from the average thickness in the width direction. The gain correction coefficient calculation unit 33 calculates the gain correction coefficient C from the gain correction coefficient table 34 based on the representative frequency f1 calculated by the representative frequency calculation unit 32, and supplies the calculated gain correction coefficient C to the variable multiplier 35. Set. The variable multiplier 35 multiplies the set gain correction coefficient C by the control gain (gains of the proportional control unit 42 and the integral control unit 43).

  In the embodiment shown in FIG. 5, the variable multiplier 35 is arranged before the proportional control unit 42 and the integration control unit 43, but may be arranged after the proportional control unit 42 and the integration control unit 43. In addition, although PI control is performed, P control or PID control may be performed.

  FIG. 6 is a diagram for explaining the effect of the present invention. FIG. 6-1 shows a case where gain correction is performed with a gain correction coefficient (when the gain compensation means 30 is present), and FIG. 6-2 shows a gain correction coefficient. It is a figure which shows the experimental result of the thickness change when not performing gain correction by (when there is no gain compensation means 30). In the figure, the horizontal axis represents time, and the vertical axis represents the deviation from the thickness average value of each bolt.

  As shown in FIG. 6, when the gain correction is performed with the gain correction coefficient, the time for convergence to the vicinity of the average thickness is much faster than when the gain correction is not performed with the gain correction coefficient. The R value is small even after convergence, indicating that the present invention is effective.

  In the above-described embodiment, a program for realizing the function of the control device 19 is recorded on the computer-readable recording medium 60 shown in FIG. 7, and the program recorded on the recording medium 60 is the same. Each function may be realized by being read and executed by the computer 50 shown in the figure.

  A computer 50 shown in the figure includes a CPU (Central Processing Unit) 51 that executes the above-described program, an input device 52 such as a keyboard and a mouse, a ROM (Read Only Memory) 53 that stores various data, an operation parameter, and the like. RAM (Random Access Memory) 54, a reading device 55 for reading a program from a recording medium 60, and an output device 56 such as a display and a printer.

  The CPU 51 implements the above-described functions by reading the program recorded on the recording medium 60 via the reading device 55 and then executing the program. Examples of the recording medium 60 include an optical disk, a flexible disk, and a hard disk.

  As described above, the sheet manufacturing apparatus control device, the sheet manufacturing apparatus, the sheet manufacturing apparatus control method, and the program executed by the computer according to the present invention are useful when the sheet has a uniform thickness in the width direction. is there.

It is a figure which shows the structure of the sheet manufacturing apparatus which concerns on one Example of this invention. It is a figure which shows the structure of a nozzle | cap | die. It is a figure which shows the flow for demonstrating control of a control apparatus. It is a figure which shows an example of a gain correction coefficient table. It is a figure which shows the structure of a control apparatus. It is a figure which shows the experimental result of the thickness change at the time of performing gain correction with a gain correction coefficient. It is a figure which shows the experimental result of the thickness change at the time of not performing gain correction with a gain correction coefficient. It is a figure which shows one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet manufacturing apparatus 11 Sheet 12 Stretching machine 13 Extruder 14 Base 15 Cooling roll 16 Winding machine 17 Conveyance roll 18 Thickness meter 19 Control device 20 Thickness adjustment means 21 Slit 30 Gain compensation means 31 Frequency component calculation part 32 Representative frequency calculation part 33 Gain Correction Coefficient Calculation Unit 34 Gain Correction Coefficient Table 35 Variable Multiplier 40 Target Value Calculation Unit 41 Subtractor 42 Proportional Control Unit 43 Integration Control Unit 44 Adder 45 Actuator 50 Computer 51 CPU
52 Input device 53 ROM
54 RAM
55 Reading device 56 Output device 60 Recording medium

Claims (12)

A lip that discharges molten resin in a sheet form, a plurality of thickness adjusting means that are provided on the lip and adjust the thickness of the resin, and the thickness of the sheet-shaped resin discharged from the lip in the width direction In a sheet manufacturing apparatus including a thickness measuring unit for measuring, based on the measurement result of the thickness in the width direction of the resin measured by the thickness measuring unit, the thickness in the width direction of the resin becomes a target value. A control device for a sheet manufacturing apparatus for controlling an operation amount of the plurality of thickness adjusting means,
Deviation calculating means for calculating a deviation of the thickness value corresponding to each operation point of the plurality of thickness adjusting means based on the measurement result of the thickness in the width direction of the resin measured by the thickness measuring means;
Of the thickness value deviations calculated by the deviation calculating means, the deviation of the thickness value within a predetermined range centered on each operation point is extracted, and then frequency conversion is performed to obtain a spatial frequency component in the width direction of the thickness value deviation. Spatial frequency component calculating means for calculating
Representative frequency calculating means for calculating a representative frequency from the spatial frequency component;
Based on the representative frequency calculated by the representative frequency calculating means, referring to characteristic data that stores the relationship between the representative frequency and the gain correction coefficient in advance, a gain correction coefficient calculating means for calculating a gain correction coefficient;
Gain correction means for multiplying the control gain of each of the operating points by the gain correction coefficient;
A control device for a sheet manufacturing apparatus.   2. The control of the sheet manufacturing apparatus according to claim 1, wherein the deviation calculating unit calculates a deviation from an arbitrarily set value of a thickness value corresponding to each operation point of the plurality of thickness adjusting units. apparatus.   The said spatial frequency component calculation means performs a window function process after extracting the deviation of the thickness value of a predetermined range centering | focusing on each said operation point, and performs the said frequency conversion after that. The control apparatus of the sheet manufacturing apparatus of 2.   The control apparatus for a sheet manufacturing apparatus according to any one of claims 1 to 3, wherein the frequency conversion is a Fourier transform.   5. The representative frequency calculating unit calculates a frequency that is a centroid value, an average value, or a center value of the spatial frequency component as the representative frequency. Control device for sheet manufacturing equipment.   A sheet manufacturing apparatus comprising the control device for a sheet manufacturing apparatus according to any one of claims 1 to 5. A lip that discharges molten resin in a sheet form, a plurality of thickness adjusting means that are provided on the lip and adjust the thickness of the resin, and the thickness of the sheet-shaped resin discharged from the lip in the width direction And a thickness measuring means for measuring at each operating point of the plurality of thickness adjusting means, the thickness in the width direction of the resin is a target based on the thickness of the resin measured by the thickness measuring means. A control method of the sheet manufacturing apparatus for controlling the operation amount of the plurality of thickness adjusting means so as to be a value,
Based on the measurement result of the thickness in the width direction of the resin measured by the thickness measuring means, a deviation calculating step for calculating a deviation of the thickness value corresponding to each operation point of the plurality of thickness adjusting means,
Among the thickness value deviations calculated in the deviation calculating step, the deviation of the thickness value within a predetermined range centered on each operation point is extracted, and then frequency conversion is performed to obtain a spatial frequency component in the width direction of the thickness value deviation. A spatial frequency component calculating step for calculating
A representative frequency calculating step of calculating a representative frequency from the spatial frequency component;
Based on the representative frequency calculated in the representative frequency calculation step, referring to characteristic data that stores a relationship between the representative frequency and the gain correction coefficient in advance, a gain correction coefficient calculation step for calculating a gain correction coefficient;
A gain correction step of multiplying the control gain of each operating point by the gain correction coefficient;
A control method for a sheet manufacturing apparatus, comprising:   The control of the sheet manufacturing apparatus according to claim 7, wherein in the deviation calculating step, a deviation from an arbitrarily set value of a thickness value corresponding to each operation point of the plurality of thickness adjusting means is calculated. Method.   In the spatial frequency component calculating step, a window function process is performed after extracting a deviation of a thickness value within a predetermined range centered on each operation point of the thickness adjusting means, and then the frequency conversion is performed. The control method of the sheet manufacturing apparatus of Claim 7 or Claim 8.   The method for controlling a sheet manufacturing apparatus according to any one of claims 7 to 9, wherein the frequency transformation is Fourier transformation.   11. The frequency according to claim 7, wherein in the representative frequency calculation step, a frequency that is a centroid value, an average value, or a center value of the spatial frequency component is calculated as the representative frequency. Control method for sheet manufacturing apparatus.   A program for causing a computer to execute each step of the control method for a sheet manufacturing apparatus according to any one of claims 7 to 11.

Images