CN113650261A

CN113650261A - Control method and control system for stabilizing pressure of rubber extruded by steel wire ring winding machine

Info

Publication number: CN113650261A
Application number: CN202111213902.XA
Authority: CN
Inventors: 韩永刚; 张晓辰; 刘勇; 张国海
Original assignee: Tianjin Saixiang Technology Co Ltd
Current assignee: Tianjin Saixiang Technology Co Ltd
Priority date: 2021-10-19
Filing date: 2021-10-19
Publication date: 2021-11-16
Anticipated expiration: 2041-10-19
Also published as: CN113650261B

Abstract

The invention discloses a control method and a control system for stabilizing the pressure of rubber extruded by a steel wire ring winding machine, wherein the control system is used for implementing the method; acquiring a traction speed, comparing a pressure feedback value with a set value, calculating a pressure difference value, and performing pressure closed-loop calculation by adopting a PID algorithm according to the traction speed and the pressure difference value to obtain a rotating speed regulating value of the extrusion screw; calculating a theoretical value of the rotating speed of the extrusion screw according to the glue coating amount and the glue discharging amount; and stably adjusting the pressure of the extruded rubber based on the sum of the theoretical value of the rotating speed of the extrusion screw and the adjusting value of the rotating speed of the extrusion screw as a set value of the rotating speed of the extrusion screw. Copper exposure or thin rubber coating of the steel wire is avoided, and the performance of the tire is improved; the waste of raw materials such as steel wires, rubber and the like caused by the problem of rubber coating is reduced.

Description

Control method and control system for stabilizing pressure of rubber extruded by steel wire ring winding machine

Technical Field

The invention relates to the technical field of tire bead ring winding, extrusion and rubber coating, in particular to a control method and a control system for controlling the pressure stability of rubber extruded by a bead ring winding machine.

Background

The steel wire of the steel wire ring winding machine is pulled out from the extruder by the tractor, the steel wire is coated with a layer of glue when the extruder head is full of rubber through the extruder, the quality of the coated glue is good and bad, the influence on the steel wire ring is large, when the steel wire is coated with glue and is thin, the viscosity between the steel wires is small, the steel wire ring is easy to fall apart after being formed, when the steel wire is coated with glue and is thick, the diameter is increased after the steel wire is coated with the glue, the arrangement of the wound steel wire ring can be irregular and disordered, and a large amount of waste of raw materials can be caused in two conditions.

In addition, when the extruder is rotated at a constant speed, a large amount of adhesive is returned due to the generation of the adhesive at the adhesive residue port, and the waste of manpower and resources is caused by the post-treatment of the returned adhesive.

In industrial control, PID algorithm is often used for realizing stable output in process control, and parameters of PID are required to be set according to actual specific conditions; for differences, if the change is too fast, the scaling factor is reduced a little. If the static error is large, the integral coefficient is adjusted. If the overshoot is large, the differential adjustment is used to perform advanced correction. Therefore, stable output is achieved, however, in the industry, the problem that the extruder stably discharges rubber is solved, the rotating speed of the winding machine is often used as a feedback value, the rubber discharging pressure is used as an adjusting value, direct adjustment is achieved, the effect of the adjustment result is not good, and the pressure output is not stable enough, so that the problem that how to apply a mature PID algorithm to the stability of the rubber extruding pressure of the steel wire ring winding machine is urgently needed to be solved is solved.

Disclosure of Invention

Therefore, the invention aims to provide a method for controlling the extrusion rubber pressure stability of a steel wire ring winding machine,

the steel wire rubber coating quality of the tire bead ring is improved, the phenomenon that the rubber is too thick due to insufficient rubber supply of an extruder and copper leakage of the steel wire or too high pressure is avoided, and the rubber return is reduced.

In order to achieve the purpose, the method for controlling the extrusion rubber pressure stability of the steel wire ring winding machine comprises the following steps:

s1, collecting a pressure value of the rubber, and correcting the collected pressure value to obtain a pressure feedback value;

s2, obtaining the traction speed, comparing the pressure feedback value with a set value, calculating a pressure difference value, and performing pressure closed-loop calculation according to the traction speed and the pressure difference value by adopting a PID algorithm to obtain a rotating speed regulating value of the extrusion screw;

s3, calculating a theoretical value of the rotating speed of the extrusion screw according to the glue coating amount and the glue discharging amount;

and S4, stably adjusting the pressure of the extruded rubber based on the sum of the theoretical value of the rotating speed of the extrusion screw and the adjusting value of the rotating speed of the extrusion screw as a set value of the rotating speed of the extrusion screw.

Further preferably, in S1, the collected pressure value is corrected by using the following formula:

F1=35*(Fd-4000)/16000；

wherein Fd is the pressure value of the collected rubber, and F1 is the pressure feedback value.

Further preferably, in S3, the glue coverage is calculated by the following formula:

V1=n*π（D²-r²）*v₁*t；

wherein V1 is the rubber coating amount of the steel wire, n is the number of the steel wire, r is the radius of the steel wire, D is the radius of the steel wire after rubber coating, V₁Is the wire drawing speed, unit: m/min, t is the steel wire drawing time.

Further preferably, in S3, the glue yield is calculated by the following formula:

V2= k*v₂*t

wherein t is the extrusion time of the extruder, k is the constant of the glue output per revolution, v₂Is the extrusion speed of the extruder.

Further preferably, in S3, the theoretical value of the rotation speed of the extrusion screw is calculated by the following method:

according to an ideal state, the rubber coating amount of the steel wire is equal to the rubber output amount of the extruder, and the theoretical value of the rotating speed of the extrusion screw is calculated according to the following formula;

v₂=n*π（D²-r²）*v₁/k；

wherein v is₂Is the extrusion speed of the extruder.

Further preferably, in S2, the extrusion screw rotation speed adjustment value is calculated by the following method:

calculating the pressure difference value between the pressure feedback value and the set value;

according to the pressure difference value and the traction speed, adjusting a proportional coefficient Kp, an integral coefficient Ki and a differential coefficient Kd of the PID;

and obtaining the rotating speed regulating value of the extrusion screw according to the adjusted proportional coefficient Kp, integral coefficient Ki and differential coefficient Kd.

The invention also provides a control system for stabilizing the pressure of the rubber extruded by the steel wire ring winding machine, which is used for implementing the control method and comprises a traction device, the extruder, a pressure sensor and a PLC (programmable logic controller), wherein the pressure sensor is used for collecting the pressure value of the rubber;

the traction device is used for drawing the rubber-coated steel wire out of the machine head of the extruder according to a set traction speed;

the extruder extrudes rubber from the extruder head by using an extrusion screw, and rubber is coated on the steel wire;

the PLC is used for correcting the collected pressure value to obtain a pressure feedback value, comparing the pressure feedback value with a set value, performing pressure closed-loop calculation by adopting a PID algorithm to obtain an extrusion screw rotating speed regulating value, and calculating an extrusion screw rotating speed theoretical value according to the glue coating amount and the glue discharging amount;

and stably adjusting the pressure of the extruded rubber based on the sum of the theoretical value of the rotating speed of the extrusion screw and the adjusting value of the rotating speed of the extrusion screw as a set value of the rotating speed of the extrusion screw.

Further preferably, the steel wire unwinding device further comprises an unwinding device, the unwinding device and the traction device clamp two ends of the steel wire, and the unwinding device is used for releasing the coiled steel wire from the spool.

Further preferably, the PLC controller includes a human-computer interaction module, and the human-computer interaction module is used for inputting parameters, and includes at least the following: the traction speed, the pressure set value and the number of steel wires of the traction device.

Preferably, the PLC controller performs data communication with the traction device, the extruder, the pressure sensor, and the unwinding device in an ethernet networking manner, and the PLC controller sets the IP addresses of the traction device frequency converter, the extruder frequency converter, the unwinding device frequency converter, and the pressure sensor, and acquires data by accessing each IP address.

Compared with the prior art, the control method and the control system for the extrusion rubber pressure stability of the steel wire ring winding machine at least have the following advantages:

1. according to the control method and the control system for stabilizing the pressure of the rubber extruded by the steel wire ring winding machine, provided by the invention, the pressure closed-loop calculation is carried out by acquiring the rubber pressure and the traction speed according to the traction speed and the pressure difference value by adopting a PID algorithm, so that the rotating speed regulating value of an extrusion screw is obtained; the pressure of the extruded rubber is stably adjusted. Copper exposure or thin rubber coating of the steel wire is avoided, and the performance of the tire is improved; the waste of raw materials such as steel wires, rubber and the like caused by the problem of rubber coating is reduced;

2. according to the control method and the control system for stabilizing the pressure of the rubber extruded by the steel wire ring winding machine, the pressure of the rubber extruded is adjusted by combining the theoretical value of the rotating speed of the extruding screw and the rotating speed regulating value of the extruding screw, so that the effects that although the traction speed changes in the operation of equipment, the pressure feedback value approaches to the pressure set value, and the pressure feedback value is stable and has small up-and-down floating are achieved; the extruder is used for supplying the glue at stable pressure, the problem of large amount of return glue is solved, and the waste of manpower and resources caused by the treatment of the return glue can be reduced; under the same working condition, the frequency of feeding glue by operators is reduced, and the operation comfort is improved.

Drawings

FIG. 1 is a schematic flow chart of a control method for stabilizing the pressure of rubber extruded by a steel wire ring winding machine according to the present invention;

FIG. 2 is a schematic structural diagram of a control system for stabilizing the pressure of the extruded rubber of the steel wire ring winding machine according to the present invention;

FIG. 3 is a schematic diagram of a control system for stabilizing the pressure of the extruded rubber of the steel wire ring winding machine according to the present invention;

FIG. 4 is a flow chart of an embodiment of the method and system for controlling the pressure stabilization of extruded rubber of a wire coil winding machine according to the present invention;

FIG. 5 is a schematic diagram of a pressure correction algorithm in accordance with an embodiment of the present invention;

fig. 6 is a schematic diagram of an algorithm for coating amount in the embodiment of the present invention.

In the figure:

1. a traction device; 2. a head of the extruder; 3. a first steel wire; 4. a second steel wire; 5. a third steel wire; 6. a unwinding device; 7. a pressure sensor; 8. an analog input module; 9. extruder transducer motors; 10. extruder screw.

Detailed Description

The invention is described in further detail below with reference to the figures and the detailed description.

As shown in fig. 1, the method for controlling the extrusion rubber pressure stability of the steel wire ring winding machine of the invention comprises the following steps:

As shown in fig. 5, in S1, the collected pressure value is corrected by using the following formula:

f1=35 (Fd-4000)/16000; (formula 1)

As shown in fig. 6, in S3, the coating amount is calculated by the following formula:

V1=n*π（D²-r²）*v₁t; (formula 2)

It should be noted that, in formula 2, the condition that the spacing between n steel wires needs to satisfy is: the distance between the n steel wires is larger than D-r.

The glue yield is calculated by adopting the following formula:

V2= k*v₂t; (formula 3)

v₂=n*π（D²-r²）*v₁k is; (formula 4) wherein v₂Is the extrusion speed of the extruder.

In S2, the extrusion screw rotation speed adjustment value is calculated by the following method:

As shown in fig. 2, the invention further provides a control system for stabilizing the pressure of rubber extruded by the steel wire ring winding machine, which is used for implementing the method, and the control system comprises a traction device 1, an extruder, a pressure sensor 7 and a PLC controller, wherein the pressure sensor 7 is used for acquiring the pressure value of rubber;

the traction device 1 is used for drawing the rubber-coated steel wire out of the extruder head 2 according to a set traction speed;

in this application, the traction device is composed of a variable frequency motor driven by a frequency converter and a storage rack.

The extruder extrudes rubber from the extruder head 2 by using an extrusion screw, and rubber is coated on the steel wire; the inside of the extruder is a shaped cavity, and rubber is contained in the cavity. This example shows 3 steel wires, the diameter of which is typically between 0.96 and 2.00 mm.

The pressure sensor 7 detects the pressure of the rubber through the deformation of a probe film and outputs a 4-20 mA signal with the measuring range of 0-35 MPa; an analog input module 8, which is used for converting the analog quantity signal of the pressure sensor into a digital quantity signal; the extruder frequency converter motor 9 has the function of outputting power and drives the extruder screw to rotate through the transmission of the speed reducer; an extruder screw 10, the function of which is to extrude rubber from a rubber feed opening to an extruder head.

The PLC is used for correcting the collected pressure value to obtain a pressure feedback value, comparing the pressure feedback value with a set value, performing pressure closed-loop calculation by adopting a PID algorithm to obtain an extrusion screw rotating speed regulating value, and calculating an extrusion screw rotating speed theoretical value according to the glue coating amount and the glue discharging amount; and stably adjusting the pressure of the extruded rubber based on the sum of the theoretical value of the rotating speed of the extrusion screw and the adjusting value of the rotating speed of the extrusion screw as a set value of the rotating speed of the extrusion screw.

Further preferably, the steel wire unwinding device further comprises an unwinding device 6, the unwinding device 6 and the traction device 1 clamp two ends of the steel wire, and the unwinding device is used for releasing the coiled steel wire from the spool.

The traction device 1 pulls the first steel wire 3, the second steel wire 4 and the third steel wire 5 (more steel wires can be used) out of the extruder head 2, the unwinding device 6 unwinds the steel wires according to the speed of the traction device 1, the extruder frequency converter motor 9 rotates according to the PLC calculation speed value, the motor drives the extruder screw 10 to rotate, the extruder screw 10 extrudes rubber to the extruder head 2 from the feeding port, and therefore the steel wires passing through the head are coated with the rubber.

As shown in figure 3, an electrical control system is formed by combining a human-computer interaction module of a PLC controller, a control module of the PLC controller, a traction frequency converter, a guide frequency converter, an extrusion frequency converter, a traction frequency conversion motor, a guide frequency conversion motor, an extrusion frequency conversion motor, an analog input module and a pressure sensor, a human-computer interface inputs a traction speed and a pressure set value, the PLC carries out PID calculation through a traction speed and pressure set feedback value, and the calculated result is set for the frequency conversion speed of the extruder, so that the pressure of a machine head is kept stable in production, and the problem of unstable steel wire coating is solved.

As shown in fig. 3-4, in one embodiment of the present invention and system, a detailed flow description is provided as follows.

S1, designing electrical hardware. Specifically, according to the functional requirement for realizing pressure stability, the type selection of electrical hardware is carried out, the frequency converter is selected according to the power of the motor, the man-machine interface and the PLC can select conventional brands and types, the pressure sensing selects 4-20 mA of current to output, interference can be inhibited, the function of line break detection is achieved, and the analog input module selects a current type.

S2, editing a man-machine parameter picture, and adding a pressure closed loop selection button, a pressure set value dialog box, a steel wire number setting dialog box and a traction speed setting dialog box on a man-machine interface.

S3, creating a PLC variable label, creating a variable label in the PLC according to the requirements of a human-computer interface, and selecting a button label, a pressure set value label, a steel wire number setting label and a traction speed setting label in a pressure closed loop.

And S4, associating the human-computer interface variables, establishing a link definition with the PLC in the human-computer interface configuration software, and then associating each variable in the picture.

S5, configuring a frequency conversion program, setting IP addresses of various frequency converters such as a traction frequency converter (which can be a plurality of frequency converters), an extruder frequency converter, a guide frequency converter (which can be a plurality of frequency converters) and the like by the frequency converter in a multi-communication mode, adding various frequency converters through a PLC (programmable logic controller), modifying parameters of the frequency converters on line or off line according to needs, focusing on the acceleration and deceleration time of the traction and extrusion frequency conversion, wherein the extrusion frequency conversion acceleration and deceleration time is less than the acceleration and deceleration time of the traction frequency conversion.

S6, programming PLC program, including programming the following parameters

1. The configuration of the pressure sensor analog quantity module (different signals or slightly different module configurations), the 7 analog quantity signal line of the pressure sensor is connected to the analog quantity module, 4-20 mA corresponds to 4000-20000 digital quantity in the module, the digital filtering is set for 10ms, the real-time sampling period is set for 100ms, and the pressure feedback digital quantity value Fd is represented in the PLC. The pressure feedback actual engineering value F1 represents a mathematical expression corresponding to F1 and Fd:

f1=35 (Fd-4000)/16000; (same formula 1)

2. The rubber coating amount of the steel wire V1, the number n of the steel wires, the radius r of the steel wire, the radius D after rubber coating and the traction speed m/V of the steel wire₁The pull-out time is t, and the mathematical expression is:

V1=n*π（D²-r²）*v₁t; (same formula 2)

It should be noted that, the conditions that the spacing between the n steel wires needs to satisfy are as follows: the distance between the n steel wires is larger than D-r.

3. The glue yield of the extruder screw is V2, and the rpm of the screw is V₂The extrusion time is t, the glue output per revolution is a constant k, and the mathematical expression is as follows: v2= k V₂T; (same formula 3)

4. Theoretically, if the glue coating quantity = the glue outlet quantity V1= V2, the rotating speed V of the screw can be calculated₂=n*π（D²-r²）*v₁K (same as formula 4).

The operation of an actual extruder is complex, the formula of rubber, the structure of a feeding port, the structure of a screw rod, the temperature of a machine barrel of the extruder and the like all influence the rubber output, a pressure sensor is required to be added to carry out pressure detection on the rubber when the pressure of the rubber of an extruder head is kept, the feedback value of the pressure is compared with a set value to carry out closed-loop control, the adjustment value calculated by the closed-loop pressure is superposed with the theoretical rotating speed value of the extrusion screw rod, and the theoretical rotating speed value is output to the speed set value of a frequency converter of the extruder(ii) a The rotating speed of the extruder is regulated to be v₃The pressure PID regulation value has positive and negative values, and when the feedback pressure is greater than the set pressure, v is₃Is negative, when the feedback pressure is less than the set pressure, v₃Is a positive value; the expression of the output rotating speed after the adjustment of the extruder is as follows: v = v₂+v₃. The PLC converts the speed v value of the extruder screw into a corresponding range numerical value of the frequency converter, and sets an address for the speed of the frequency converter of the extruder.

And S7, adjusting PID parameters. After programming, the pressure feedback value is downloaded to a PLC for load test, the difference between the pressure set value and the pressure feedback value is observed, the proportional coefficient Kp, the integral coefficient Ki and the differential coefficient Kd of the PID are adjusted, and the effects that the pressure feedback value approaches to the pressure set value and is stable and has small up-and-down floating in the running process of equipment are achieved.

Kp regulation: and the controller generates a control action for reducing the error once the deviation is generated. When the deviation e =0, the control action is also 0. Thus, the proportional control is adjusted based on the deviation, i.e. there is a difference adjustment.

Ki regulation: the error can be memorized, the method is mainly used for eliminating static error and improving the non-difference degree of a system, the strength of the integral action depends on an integral time constant Ti, the larger the Ti is, the weaker the integral action is, and the stronger the integral action is otherwise.

Kd regulation: the change trend (change rate) of the deviation signal can be reflected, and an effective early correction signal can be introduced into the system before the value of the deviation signal becomes too large, so that the action speed of the system is accelerated, and the adjusting time is shortened.

In the actual debugging process, parameters are set according to actual specific conditions, when the difference value is large, the proportional coefficient Kp is adjusted to gradually reduce the difference value and maintain the difference value in a stable range, but when the Kp is adjusted independently, the pressure jitter phenomenon can occur, so that a static error needs to be observed, and if the static error is large, the integral coefficient is adjusted; further, if the overshoot is large, the differential adjustment is used for correcting in advance, thereby ensuring the pressure of the extruded rubber to be stably output by the extruder.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims

1. A control method for stabilizing the pressure of rubber extruded by a steel wire ring winding machine is characterized by comprising the following steps:

2. The method for controlling the pressure stabilization of the extruded rubber of the steel wire coil winding machine according to claim 1, wherein in S1, the collected pressure value is corrected by using the following formula:

F1=35*(Fd-4000)/16000；

3. The method for controlling the pressure stability of the extruded rubber of the wire coil winding machine according to claim 1, wherein in S3, the rubber coating amount is calculated by using the following formula:

V1=n*π（D²-r²）*v₁*t；

4. The method for controlling the pressure stability of the extruded rubber of the wire coil winding machine according to claim 3, wherein in S3, the rubber output is calculated by the following formula:

V2= k*v₂*t

5. The method for controlling the pressure stability of the extruded rubber of the steel wire ring winding machine according to claim 4, wherein in S3, the theoretical value of the rotating speed of the extrusion screw is calculated by the following method:

v₂=n*π（D²-r²）*v₁/k

wherein v is₂Is the extrusion speed of the extruder.

6. The method for controlling the pressure stabilization of the extruded rubber of the wire coil winding machine according to claim 1, wherein in S2, the adjusting value of the rotation speed of the extruding screw is calculated by the following method:

7. A control system for stabilizing the pressure of rubber extruded by a wire coil winding machine is characterized by being used for implementing the control method of any one of claims 1 to 6, and comprising a traction device, the extruder, a pressure sensor and a PLC (programmable logic controller), wherein the pressure sensor is used for collecting the pressure value of the rubber;

8. The control system for controlling the pressure stabilization of the extruded rubber of the steel wire ring winding machine according to claim 7, further comprising a unwinding device, wherein the unwinding device and the traction device clamp two ends of the steel wire, and the unwinding device is used for releasing the coiled steel wire from the spool.

9. The system for controlling the pressure stabilization of the extruded rubber of the steel wire ring winding machine according to claim 7, wherein the PLC comprises a human-computer interaction module, and the human-computer interaction module is used for inputting parameters and at least comprises the following parameters: the traction speed, the pressure set value and the number of steel wires of the traction device.

10. The system for controlling the pressure stabilization of the extruded rubber of the steel wire ring winding machine according to claim 7, wherein the PLC is in data communication with the traction device, the extruder, the pressure sensor and the unwinding device in an Ethernet networking manner, and IP addresses of the traction device frequency converter, the extruder frequency converter, the unwinding device frequency converter and the pressure sensor are set in the PLC, so that data can be obtained by accessing the IP addresses.