CN107253320B - BOPP film thickness fuzzy control method - Google Patents

Abstract

The invention discloses a kind of BOPP film thickness fuzzy control methods, film thickness is detected by THICKNESS GAUGE FOR THE MEASUREMENT OF THIN FOILS, data processing module extracts the film profile thickness value set for being marked with diebolt position, based on the numerical value set, second controller in control module is according to the thickness deviation for closing on bolt location when front bolt and its left and right, control amount is calculated through fuzzy reasoning and temperature control is carried out to the bolt through die head adjuster, while the first controller adjusts frequency converter revolving speed by PID control.Based on expert's operating experience of die lips aperture control, the present invention realizes that film transverse gage is uniform, while be consistent film longitudinal thickness by the adjusting of extruded velocity by the decoupling between fuzzy control solution die head adjacent bolt.

Description

BOPP film thickness fuzzy control method

Technical field

The present invention relates to film fabrication techniques fields, and in particular to a kind of BOPP film thickness fuzzy control method.

Background technique

BOPP film, that is, bidirectional stretching polypropylene film be as obtained by biaxial tension, it be by physics, chemistry and The plastic product that the means specially-shaped such as machinery is process.BOPP production line is non-linear, a time-varying, the complexity postponed greatly System.Its process flow specifically include that raw material melting, extrusion, cooling and shaping, longitudinal stretching, cross directional stretch, trimming, at corona It manages, batch.

Physical mechanical property such as tensile strength, elongation at break, turbidity, gloss as BOPP film product quality indicator Deng because depending mainly on the attribute of material itself, so all easily reaching requirement.And as the main of re-workability and service performance Con trolling index, i.e. film gauge variation and Film Average Thickness deviation, then depend mainly on the manufacturing process of film.Even if manufacture For plastics thickness control in the deviation range that standard allows, but after the winding of thousands of tunics is accumulative, thickness deviation is big in the process Position on may form the bad defects such as hoop, sudden and violent muscle or chase, the reprocessing that these defects directly influence user uses, Such as phenomena such as the dislocation of color printing chromatography or gluing irregular corrugation, it is set to reduce or lose use value, so in BOPP film production Topic is how to improve and stabilizing films thickness and precision between the quality of most critical.

The control of film thickness is based on infrared ray, X-ray, β ray equal thickness detection technique.Such as application No. is 2014201577223 Chinese patent by X-ray scanning obtain film thickness after, be respectively adopted two PID regulators come into The control of the horizontal and vertical thickness of row film.Similar side is also used application No. is 2007201517097 Chinese patent Method points out simultaneously, in order to obtain film in homogeneous thickness, it is necessary to realize that thickness measurements and measurement position are accurately positioned. Application No. is 2015102638543 Chinese patents then by comparing to the thickness value measured and preset thickness value Analysis adjusts the extrusion output at extruder die head, to realize that the uniformity for squeezing out composite membrane longitudinal thickness is adjusted.

The thickness control of BOPP film manufacture at present is mostly realized based on the discrete control system in production line, often Using traditional pid control mode.But practice and find by long period of operation, on the one hand in process of production due to BOPP It stretches and non-homogeneous, so that there are errors between fastener locations and physical location；Still further aspect is deposited between adjacent bolt In coupling, the variation that single bolt will cause other positions thickness is adjusted, moreover, as extruder uses the passage of time, The small variations of mechanism itself will aggravate these problems.Therefore, traditional PID control is difficult to obtain ideal thickness uniformity.

Summary of the invention

In view of this, it is an object of the invention to by the observation analysis to extruder die head lip aperture control law, A kind of fuzzy control method that can utilize expert's operating experience is provided, by bolt corresponding to film profile thickness controlled volume itself and The thickness deviation group that bolt is closed in its left and right is combined into array as input quantity, calculates through fuzzy reasoning and obtains output quantity and through die head Adjuster to carry out temperature control to bolt, to obtain the uniform of film transverse gage, while to film longitudinal thickness carry out with Track and adjusting.

The technical solution of the invention is as follows, provides a kind of BOPP film thickness fuzzy control method comprising following step It is rapid:

S1) film raw material melt is cooled and shaped unit after extruder extrusion and is cured as slab, slab drawn unit It is stretched as after wide volume film by rolling unit harvesting being parent roll, the film that thickness measuring unit carries out Thickness sensitivity to film and generates is thick Degree information is transferred to data processing module through the acquisition module in monitoring control unit；

S2) data processing module handles film thickness information, extracts film thickness data set and is transferred to control Molding block；

S3) control module calculates the thickness deviation of position corresponding to it to bolt as second controller and its spiral shell is closed in left and right The thickness deviation mean value of position corresponding to bolt calculates through fuzzy reasoning and obtains control amount corresponding to the bolt and adjust through die head Device carries out temperature control to the bolt；Film profile average thickness is tracked according to the film thickness data set by the first controller simultaneously It changes with time, the control amount for obtaining the frequency converter being connected with extruder is calculated through PID control, is squeezed out by Frequency Converter Control Machine revolving speed.

Preferably, the fuzzy reasoning calculating is carried out in a manner of On-line accoun, it is defeated to two according to value range in advance Enter the subordinating degree function of one output quantity ambiguity in definition variable of amount, and is summarized the experience out fuzzy control rule according to execute-in-place Library；Then, fuzzy control calculating is periodically carried out, i.e. it is right to close on bolt institute for the thickness deviation to bolt position and its left and right The thickness deviation mean value for answering position is mapped to fuzzy domain through defuzzification interface, then is completed by indistinct logic computer according to rule base Fuzzy reasoning is converted to reality output amount by the fuzzy value that ambiguity solution interface obtains inference machine.

Preferably, film thickness information is generated as sending the image to after film profile image by the thickness measuring unit Display module is simultaneously transferred to data processing module through film thickness data acquisition module, and described image includes indicating in different colors respectively A film thickness curve, reference axis and the auxiliary line parallel with reference axis；The film thickness data set is to be marked with diebolt position The film profile thickness value set set.

Preferably, the display module further includes man-machine interface, the interface includes film product thickness input module With calculating parameter input module, the control module is also connected with the cooling and shaping unit, draw unit and rolling unit.

Preferably, the display module includes display and VGA signal distributor, the VGA signal distributor is from survey Thick instrument receives VGA picture signal and signal is distributed to display and the film thickness data acquisition module.

Preferably, the thickness measuring unit includes the first calibrator and the second calibrator, first calibrator and second Calibrator is located at draw unit both ends and carries out Thickness sensitivity to the slab and wide volume film.

Preferably, the second controller controls diebolt solid-state die head adjuster in a manner of duty ratio The on-off of relay, thus the aperture of die head section where adjusting the bolt by the temperature for controlling bolt, to realize the bolt The thickness of corresponding film section is adjusted.

Using the solution of the present invention, compared with prior art, have the advantage that the present invention is applied to BOPP production Plastics thickness control, acquires the film thickness information of calibrator in real time, and analysis handles to obtain the real-time thickness parameter of film, pass through Fuzzy control realizes the decoupling between die head adjacent bolt, and the expertise of extruder die head lip aperture control is utilized, The uniform and stable of BOPP film transverse gage is realized, realizes the consistent of its longitudinal thickness further through feedback control.

Detailed description of the invention

Fig. 1 is the control system architecture schematic diagram for applying BOPP film thickness fuzzy control method of the present invention；

Fig. 2 is that film thickness data acquire structural schematic diagram；

Fig. 3 is film profile thickness curve schematic diagram corresponding with diebolt；

Fig. 4 is the template matching flow chart of data processing module；

Fig. 5 is that data processing module extracts aim curve data flowchart；

Fig. 6 is film thickness curve comparison figure；

Fig. 7 is the statistical result of film thickness extraction of values；

Fig. 8 is plastics thickness control flow diagram；

Fig. 9 is film transverse gage fuzzy control flow diagram；

Figure 10 is film transverse gage fuzzy control rule table.

Specific embodiment

The preferred embodiment of the present invention is described in detail below in conjunction with attached drawing, but the present invention is not restricted to these Embodiment.The present invention covers any substitution made in the spirit and scope of the present invention, modification, equivalent method and scheme.

In order to make the public have thorough understanding to the present invention, it is described in detail in the following preferred embodiment of the present invention specific Details, and the present invention can also be understood completely in description without these details for a person skilled in the art.

The present invention is more specifically described by way of example referring to attached drawing in the following passage.It should be noted that attached drawing is adopted With more simplified form and using non-accurate ratio, only to facilitate, lucidly aid in illustrating the embodiment of the present invention Purpose.

As shown in Figure 1, the control system for applying BOPP film thickness fuzzy control method of the present invention includes: extrusion unit 1, it is cooled and shaped unit 2, draw unit 3, thickness measuring unit, monitoring control unit 5 and rolling unit 6, is wrapped wherein squeezing out unit 1 Extruder 7 is included, has die head 8 in extruder front end, draw unit 3 includes that vertical drawing-die block 9 and horizontal drawing-die block 10, thickness measuring unit then wrap The first calibrator 401 and the second calibrator 402 are included, monitoring control unit 5 includes film thickness data acquisition module 12, data processing mould Block 13, control module 14, die head adjuster 15 and frequency converter 16.

Film raw material squeezes out for melt from die head 8 from melting after the feeding port of extruder 7 investment, then through being cooled and shaped unit 2 are cured as slab, and slab drawn unit 3 is stretched as after wide volume film by the harvesting of rolling unit 6 being parent roll, subsequent to press order It is required that being cut and being packed to parent roll.Since thickness plays a crucial role product quality, in BOPP film Thickness real-time monitoring often is carried out to slab and wide volume film respectively with two calibrators in production, two calibrators are pressed outward Output thickness data, while they are also connected with display module to show the sectional thickness image of slab or wide volume film.Two Front uses the first calibrator 401 of slab thickness measuring in pull-out at the beginning of film in calibrator, waits until the second calibrator 402 below Just pause uses after investment.

In conjunction with shown in Fig. 1~2, preferably, system further includes display module 11.First calibrator 401 and the second thickness measuring Film thickness information is generated as after film profile image sending the image to display module 11 and through film thickness data by instrument 402 Acquisition module 12 is transferred to data processing module 13.Preferably, display module 11 can also include two VGA signal distributors That is VGA Splitter 112 and 113, the first calibrator 401, the second calibrator 402 are issued display module 11 respectively by them VGA signal carries out being divided into two-way, uses all the way for display 111, acquires use for film thickness image pickup units 12 all the way.It is described Display can show two-way VGA signal for two independent displays or a display timesharing.

As shown in Figure 3a, film thickness data collecting module collected to film profile image in, have two width sections thick respectively It writes music line chart and some character informations；Wherein, a-quadrant indicates the corresponding thickness a reference value of film thickness profile axis of abscissas The longitudinal coordinate scale value 5% of coordinate system in 35.5um and curve picture；The region C is the target thickness for stating current film profile It writes music line, reference axis is set by the description of a-quadrant, and the auxiliary line parallel with reference axis is also contained in coordinate system；B area Middle AVG=35.51um refers to the thickness average value of current film profile shown by C region curve, and R=2.83% is then bent The very poor value of statistics that line fluctuates up and down.Since film profile image has these Block Characteristics, BOPP film of the present invention A pretreatment unit is arranged in thickness fuzzy control method in data processing module, according to film profile image collected In color characteristic and the first ROI region of Region Feature Extraction and the 2nd region ROI；Wherein, the first ROI region be a-quadrant and B area, and the second ROI region is then the region C.

In conjunction with shown in Fig. 3 a and 3b, the film profile thickness curve horizontally corresponds to extruder die hook bolt collection It closes.Wherein, as shown in Figure 3b, lower section rectangle illustrates die head, and internal triangle is bolt.BOPP film production is in slab cross During drawing, draw ratio is 7-9 times, and for the wide volume specification of such as 8280mm, slab width is about 1000mm, die head spiral shell When bolt is 39, it is about 25mm that each bolt, which corresponds to slab width, removes the comparatively fixed bolt in both ends, each tune in middle part Saving the corresponding width range in figure of bolt is about 1/35.As can be seen from the figure:

In the aperture control for carrying out die lips, if the bolt at R, which only presses this place thickness deviation size, carries out temperature Adjusting takes a larger output valve, at the same at S be also by this place thickness deviation size carry out control take one close to 0 value；That , due to deviation very little at S, although the control amount very little of itself is opened at R due to the influence of bolt control amount at R at S Degree will become smaller and by traction so that the lip at adjacent S becomes smaller, so that the deviation at S becomes negative value, and deviation range It is bigger than initial value, it is not inconsistent with ideal effect.

For this purpose, present invention introduces practical operation experience, these are summarized the experience as fuzzy control rule, fuzzy control is passed through To adjust the uniformity of lateral film thickness.And before control, it first to be obtained by data processing module and be marked with diebolt position The data acquisition system is simultaneously transmitted control module by the film profile thickness value set set, obtains current film thickness so as to calculate Deviation.

In conjunction with shown in Fig. 3 to Fig. 5, during thickness control, data processing module wants output token to have diebolt position Film profile thickness value set, based on film profile image, content includes: one indicated in different colors respectively Film thickness curve, reference axis and the auxiliary line parallel with reference axis.To the film thickness curve, its benchmark thickness can be set by calibrator Angle value, coordinate scale value.

Data processing module in BOPP film thickness fuzzy control method of the present invention, inside include character extracting sub-module With film thickness data extracting sub-module, the two submodules the former read or mentioned from the film profile image by character recognition Take root thickness value, the coordinate scale value, thickness average value of film thickness curve in image；The latter is then based on these numerical value, and from After extracting a continuous whole and achiasmate film thickness curve in image, to point each on the curve, in the picture by it Pixel coordinate conversion is corresponding thickness value, and obtains diebolt according to the extreme point of the curve and determine on curve Position.

As shown in figure 4, character extracting sub-module is first according to the character analysis building word being likely to occur in the first ROI region The binaryzation feature templates library of symbol；Then, for the first acquired ROI region, detection isolate single character and to its into It goes and binaryzation etc. is handled, then, carry out template matching after extracting feature to each character, then recognize to phrase, obtain Root thickness value, the coordinate scale value, thickness average value of described image Central Plains film thickness curve.

As shown in figure 5, film thickness data extracting sub-module is directed to the region C in the second acquired ROI region, that is, Fig. 3 a, Gray processing and filtering processing are carried out to target image first, obtain discontinuous film thickness curve further according to color component and translation specifications Image g1 and auxiliary dot matrix image g2；Otsu is carried out respectively that is, to two images g1 and g2 secondly, carrying out gradient threshold segmentation Binary image g1 ' and g2 ' are obtained after Threshold segmentation and Double Thresholding Segmentation；Then, g1 ' is mutually merged into generation one with g2 ' the two Item is continuous whole and achiasmate film thickness curve image g；Finally, according to the acquired root thickness value, coordinate scale value, Its pixel coordinate conversion in the picture is corresponding thickness to each point on generated film thickness curve by thickness average value Value, and bolt positioning is carried out by label, each bolt location is marked on thickness curve.

It is illustrated in figure 6 film thickness curve comparison figure, wherein Fig. 6 a is that an original thickness curve and film thickness data extract son The comparison diagram of the extracted curve of module, Fig. 6 b are the partial enlarged view of Fig. 6 a.It can be seen from the figure that extracted curve and original are thick Line of writing music is identical.

Fig. 7 gives the method for the present invention and film profile shown in Fig. 3 is measured in real time and is handled the film thickness obtained Degree evidence, wherein thickness mean value and thickness value are used as subsequent control input signal, and the very poor value of thickness is then one and is used as The index of aid prompting.In terms of from the relative deviation of real data and data measured, thickness mean value difference 0.28%, the very poor value of thickness Difference 1.77%, accuracy is high, fully meets requirement of engineering, provides thickness data feedback precisely in real time for control module.

As shown in figure 8, being based on thickness value set, BOPP film thickness fuzzy control method of the present invention passes through fuzzy control It carries out the control of lateral film thickness uniformity, while also adjusting longitudinal thickness by PID control, BOPP film of the invention is thick Spend control flow are as follows:

(L1) mark slab after melt extrusion, slab before the stretching after Thickness sensitivity carried out by calibrator, generate film Profile image；

(L2) the film thickness data acquisition module in control unit is monitored after calibrator acquisition film profile image, by data Processing module carries out processing analysis to the image, obtains the film profile thickness value set for being marked with diebolt position；

(L3) to each element of the thickness value set, kth segment data is taken, its thickness value is preset with product thickness Value, which is compared, obtains deviation combination, which send second controller i.e. controller 2 to carry out the control of film thickness transverse regularity, output Control amount adjusts the duty ratio of k-th of bolt heating waveform by die head adjuster, to adjust the aperture of this section of die lips；

(L4) to the thickness value set obtained in L2, calculate film profile thickness average value in this period, by its with Product thickness preset value, which is compared, obtains this period integral thickness deviation, which send the first controller i.e. controller 1 to carry out PID control, output control amount adjust frequency converter, change extruder revolving speed, to adjust the extrusion in the die head whole unit time Flow, that is, extruded velocity；

(L5) it waits next period to be timed to come, returns to step L2.

In the above control process, thickness deviation is converted to temperature compensation value by second controller, passes through die head adjuster The on-off of solid-state relay on computer heating control channel is controlled in a manner of duty ratio, to control the temperature of current diebolt Degree.Due to the expansion and contraction property of metal, the gap compression of slab lip, the film of such slab lip when heater conducting Thickness can be gradually reduced, on the contrary then increase.

First controller is periodically averaged laterally upper film thickness data, converts as unit time extrusion output, Compared with extrusion output corresponding with product thickness setting value, extrusion output deviation is obtained, then be transformed into motor speed compensation rate, pass through Change the input quantity of frequency converter to control the revolving speed of main extruder.When motor speed increases, the melt of extruder die head lip Flow increases, and pressure increases, and the film integral thickness after corresponding slab and stretching can gradually increase.

Control module further include control vertical drawing, the speed of each roller and the submodule of temperature in horizontal drawing and rolling unit, It is adjusted according to production film thickness according to preset technological parameter.

It is illustrated in figure 9 the film transverse gage fuzzy control process of second controller comprising following steps:

(M1) fuzzy rule base is summed up to the control experience of die lips aperture with reference to experienced operator；By from Line optimum experimental control parameter, the scale factor of quantizing factor and output control amount including input variable, Initialize installation；

(M2) k-th of bolt and its left and right phase are extracted from the film profile thickness value set for being marked with diebolt position Thickness deviation values at adjacent bolt, are compared with product thickness, calculate basic deviation es and adjacent deviation ea；

(M3) es and ea are passed through after quantizing factor ks and ka are quantified respectively again by the degree of membership of respective fuzzy subset Function Mapping is to fuzzy domain, then, completes fuzzy reasoning according to the rule base that fuzzy relation indicates by indistinct logic computer, finally The fuzzy value for obtaining inference machine through ambiguity solution interface is converted to digital quantity, and defeated multiplied by control amount ht is obtained after scale factor ku Die head adjuster is given out.

In fuzzy control used by film thickness transverse regularity controls, the subordinating degree function of each fuzzy subset is all made of triangle Shape；Since the shape of subordinating degree function is more sharp, control sensitivity is higher, and therefore, basic deviation ES and adjacent deviation EA are zero The shape of value areas adjacent is set to more steep.

In production process, when es is negative value, illustrate that this section of die lips aperture is too small, it should increase aperture, adjust spiral shell Bolt will reduce temperature, i.e. control amount is negative value.With reference to expert's operating experience, 29 fuzzy controls rule as shown in Figure 10 are summarized Then, every rule is described using " IF A THEN B " form, such as:

IF ES=NB and EA=NB or NM THEN HT=NB.

Adjacent deviation can take the deviation mean value when front bolt or so each one or each two bolts, and fuzzy reasoning is using taking Greatly-and small (MAX-MIN) method is taken, ambiguity solution uses gravity model appoach.

Preferably, can be spaced a progress aperture control when being adjusted to bolt or several bolts are one group.

Preferably, the amplitude of accommodation can be realized, so that middle part bolt tune by non-uniform Distribution by changing scale factor Section amount is small, and both sides are then gradually big.

In addition to this, although embodiment is separately illustrated and is illustrated above, it is related to the common technology in part, in this field Those of ordinary skill apparently, can be replaced and integrate between the embodiments, be related to one of embodiment and record is not known Content, then can refer to another embodiment on the books.

Embodiments described above does not constitute the restriction to the technical solution protection scope.It is any in above-mentioned implementation Made modifications, equivalent substitutions and improvements etc., should be included in the protection model of the technical solution within the spirit and principle of mode Within enclosing.

Claims (5)

1. a kind of BOPP film thickness fuzzy control method comprising following steps:

S1) film raw material melt is cooled and shaped unit after extruder extrusion and is cured as slab, and slab drawn unit stretches It is parent roll to be received and kept after width volume film by rolling unit, the film thickness that thickness measuring unit carries out Thickness sensitivity to film and generates is believed Breath is transferred to data processing module through the acquisition module in monitoring control unit；

S2) data processing module handles film thickness information, extracts film thickness data set and is transferred to control mould Block；

S3) control module calculates the thickness deviation of position corresponding to it to bolt as second controller and its bolt institute is closed in left and right The thickness deviation mean value of corresponding position calculates through fuzzy reasoning and obtains control amount corresponding to the bolt and through die head adjuster pair The bolt carries out temperature control；Film profile average thickness is tracked at any time according to the film thickness data set by the first controller simultaneously Between variation, calculate the control amount of frequency converter for obtaining and being connected with extruder through PID control, pass through Frequency Converter Control extruder turn Speed,

Wherein, the fuzzy reasoning calculating is carried out in a manner of On-line accoun, in advance according to value range to two input quantity one The subordinating degree function of output quantity ambiguity in definition variable, and summarized the experience out fuzzy rule base according to execute-in-place；Then, all The thickness that the progress fuzzy control calculating of phase property, the i.e. thickness deviation to bolt position and its left and right close on position corresponding to bolt Deviation mean value is spent, is mapped to fuzzy domain through defuzzification interface, then fuzzy reasoning is completed according to rule base by indistinct logic computer, after The fuzzy value for obtaining inference machine through ambiguity solution interface is converted to reality output amount,

Wherein, the fuzzy rule base includes at least following control rule:

IF ES=NB and EA=NB or NM THEN HT=NB,

The second controller controls the on-off of diebolt solid-state relay die head adjuster in a manner of duty ratio, To adjust the aperture of bolt place die head section by the temperature for controlling bolt, to realize film section corresponding to the bolt Thickness adjust.

2. a kind of BOPP film thickness fuzzy control method according to claim 1, it is characterised in that: the thickness measuring unit Film thickness information is generated as after film profile image to send the image to display module and through film thickness data acquisition module Be transferred to data processing module, described image include the film thickness curve indicated in different colors respectively, reference axis and with seat The parallel auxiliary line of parameter；The film thickness data set is the film profile thickness value set for being marked with diebolt position.

3. a kind of BOPP film thickness fuzzy control method according to claim 2, it is characterised in that: the display module It further include man-machine interface, the interface includes film product thickness input module and calculating parameter input module, the control mould Block is also connected with the cooling and shaping unit, draw unit and rolling unit.

4. a kind of BOPP film thickness fuzzy control method according to claim 2, it is characterised in that: the display module Including display and VGA signal distributor, the VGA signal distributor receives VGA picture signal from calibrator and divides signal Dispensing display and the film thickness data acquisition module.

5. a kind of BOPP film thickness fuzzy control method according to claim 1, it is characterised in that: the thickness measuring unit Including the first calibrator and the second calibrator, first calibrator and the second calibrator are located at draw unit both ends to institute It states slab and wide volume film carries out Thickness sensitivity.