A method and system for controlling the operation of a sole material production line

Abstract

The present application relates to the technical field of process control, in particular to a kind of sole material production line operation process control method and system.The present application distinguishes short-time material shortage from continuous material shortage according to the continuous change of calendering discharge state, after confirming continuous material shortage, first make receiving material conveyor belt and cooling line enter standby state, and after the sole material in cooling line is discharged, stop running again, so as to give consideration to the continuation of the remaining sole material conveying and shutdown control under no material state.After the sole material resumes discharging, the present application first confirms that the feeding state has been restored, then adjusts the running speed of receiving material conveyor belt and cooling line according to the actual running state of calendering machine main shaft, and corrects the speed by combining receiving material motor load change, so that the calendering discharge speed and subsequent conveying speed are kept corresponding, reduce the idle running during material shortage, at the same time, reduce the possibility of material accumulation, stretching and conveying connection abnormality when resuming discharging.

Description

Technical Field

[0001] This invention relates to the field of process control technology, and in particular to a method and system for controlling the operation of a shoe sole material production line. Background Technology

[0002] The process control method for shoe sole material production line operation refers to continuously acquiring the processing status of raw materials after they enter the production line according to the production process of shoe sole materials, judging the equipment operation status according to the connection requirements between each process, and then sending corresponding control instructions to the production equipment so that the raw material supply process, processing process and conveying process run in the preset process sequence.

[0003] Traditional methods for controlling the operation of shoe sole material production lines, while capable of acquiring equipment operating status and controlling production equipment according to the production flow, can be problematic. When the calender continues to operate while the material supply gradually decreases or is temporarily interrupted, instantaneous changes in status can easily be confused with persistent material shortages. This can lead to premature shutdowns of the receiving conveyor and cooling line, or continued operation even after material has been exhausted. Premature shutdowns leave undischarged shoe sole material in the cooling line, while delayed shutdowns cause the receiving conveyor and cooling line to run continuously without load. When shoe sole material is discharged again, if the receiving conveyor and cooling line resume operation at the speed before shutdown, inconsistent operating speeds among the equipment can cause material accumulation or tension. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and to propose a method and system for controlling the operation of a shoe sole material production line.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for controlling the operation process of a shoe sole material production line, comprising the following steps: Obtain a state vector set characterizing the operating state of the calender and the actual conveying state of the sole material; wherein, the state vector set includes the calender spindle speed signal, the real-time current signal of the calender main drive motor, the real-time thickness profile sequence, and the actual conveying speed of the sole material; Based on the state vector set, determine whether the current calender is in a main machine shutdown state, a suspected material shortage state, a continuous material shortage state, or a normal material discharge state; When the main machine is stopped, in normal material discharge mode, or in suspected material shortage mode, maintain the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor; when in continuous material shortage mode, control the receiving conveyor belt motor and the cooling line drive motor to standby mode. When in standby mode, if there is no residual material inside the cooling line and the continuous material shortage mode does not change, control the receiving conveyor belt motor and the cooling line drive motor to stop. When the receiving conveyor belt motor and the cooling line drive motor are in standby or stopped state, the state vector set determines the judgment flag for maintaining the material shortage condition or the judgment flag for resuming the material discharge condition. When a "Maintain Material Shortage" condition determination flag is generated, maintain the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor; when a "Restore Discharge" condition determination flag is generated, adjust the operating speed of the receiving conveyor belt and the cooling line to synchronize them with the actual speed of the calender spindle at a fixed speed ratio.

[0006] A process control system for a shoe sole material production line, the system comprising: The vector set construction module obtains a state vector set representing the operating state of the calender and the actual conveying state of the sole material; wherein, the state vector set includes the calender spindle speed signal, the real-time current signal of the calender main drive motor, the real-time thickness profile sequence, and the actual conveying speed of the sole material; The working condition determination module determines whether the current calender is in a main machine shutdown condition, a suspected material shortage condition, a continuous material shortage condition, or a normal material discharge condition based on the state vector set. The equipment control module maintains the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor when the main machine is stopped, the material is being discharged normally, or the material shortage is suspected. When the material shortage is continuous, the receiving conveyor belt motor and the cooling line drive motor are put into standby mode. When in standby mode, if there is no residual material inside the cooling line and the continuous material shortage condition does not change, the receiving conveyor belt motor and the cooling line drive motor are stopped. The recovery determination module determines whether to maintain the material shortage condition determination flag or restore the material discharge condition determination flag based on the state vector set when the material receiving conveyor belt motor and the cooling line drive motor are in standby or stopped state. The synchronization control module maintains the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor when a material shortage condition judgment flag is generated; when a material discharge condition judgment flag is generated, it adjusts the operating speed of the receiving conveyor belt and the cooling line to synchronize them with the actual speed of the calender spindle at a fixed speed ratio.

[0007] Compared with the prior art, the advantages and positive effects of the present invention are as follows: This invention distinguishes between short-term and continuous material shortages based on the continuous changes in the calender's output state. Upon confirming a continuous material shortage, the receiving conveyor belt and cooling line are first put into standby mode. Operation ceases only after the sole material is discharged from the cooling line, thus balancing the continued conveying of remaining sole material with shutdown control during material shortages. After sole material output resumes, the invention first confirms that the feeding state has been restored. Then, it adjusts the operating speed of the receiving conveyor belt and cooling line according to the actual operating state of the calender spindle, and corrects the speed based on changes in the receiving motor load. This ensures that the calender output speed corresponds to the subsequent conveying speed, reducing idle operation during material shortages and minimizing the possibility of material accumulation, stretching, and abnormal conveying connections during material recovery. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the steps of the method of the present invention; Figure 2 This is a flowchart illustrating the steps and principles of the method of the present invention. Figure 3 This is a block diagram of the system of the present invention. Detailed Implementation

[0009] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0010] Please see Figure 1-2 This invention provides a technical solution: a method for controlling the operation of a shoe sole material production line, comprising the following steps: S1: Obtain the state vector set representing the operating state of the calender and the actual conveying state of the shoe sole material, including: First, a laser thickness sensor is installed at the discharge position of the calender, with its measurement direction perpendicular to the surface of the sole material. The sampling clock of the laser thickness sensor is synchronized with the timing reference of the calender. As the sole material passes the measurement position of the laser thickness sensor, the sensor sequentially outputs the sampling time and the corresponding sampling point thickness. The sampling point thickness represents the actual thickness of the sole material at the measurement position at the corresponding sampling time. The thickness of each sampling point is read from earliest to latest according to the sampling time. Earlier sampling times correspond to the material positions that pass the measurement position first in the material transport direction, and later sampling times correspond to the material positions that pass the measurement position later in the material transport direction. The thicknesses of each sampling point are arranged sequentially according to their corresponding material positions, maintaining a one-to-one correspondence between sampling time and sampling point thickness, thereby generating a real-time thickness profile sequence.

[0011] An industrial camera is installed above the discharge position of the calender, ensuring its field of view covers the calendered surface of the sole material. The camera captures image frames sequentially at continuous sampling times and inputs these frames into an industrial computer equipped with MATLAB software and an image processing toolbox. Surface texture edges represent the locations where pixel brightness changes between the sole material's surface texture and adjacent surface areas. Surface texture edge pixel coordinates represent the pixel positions of the surface texture edges in the horizontal and vertical directions of the image. Pixel brightness values ​​in adjacent image frames are read sequentially, and the direction of change in brightness values ​​is compared along the sole material's transport direction. Locations where brightness values ​​change from continuously increasing to continuously decreasing, or from continuously decreasing to continuously increasing, are recorded as surface texture edge pixel coordinates. Based on the extension direction, arrangement order, and adjacent position relationships of the surface texture edges, the surface texture edge pixel coordinates in the previous image frame are paired one-to-one with the corresponding surface texture edge pixel coordinates in the next image frame. Pixel movement distance = (pixel coordinates of the surface texture edge along the transmission direction in the next image frame) - (pixel coordinates of the surface texture edge along the transmission direction in the previous image frame). Sampling time interval = (sampling time of the next image frame) - (sampling time of the previous image frame). Pixel movement speed = (pixel movement distance) / (sampling time interval), where pixel movement speed represents the number of pixels the surface texture edge moves along the shoe sole material transmission direction per unit sampling time. Two calibration points with known actual spacing are set within the field of view of the industrial camera. The pixel coordinates of the two calibration points in the image are read. Pixel spacing between the two calibration points = (pixel coordinates of the second calibration point along the calibration direction) - (pixel coordinates of the first calibration point along the calibration direction). Camera calibration coefficient = (actual spacing between the two calibration points) / (pixel spacing between the two calibration points), where the camera calibration coefficient represents the actual distance corresponding to a single pixel. Actual shoe sole material conveying speed = (pixel movement speed) × (camera calibration coefficient), thus obtaining the actual shoe sole material conveying speed.

[0012] After the industrial camera and laser thickness sensor begin continuous data acquisition, a speed sensor is installed at the end of the calender spindle. The speed sensor reads the number of rotations of the calender spindle per unit time according to the same sampling period, forming a calender spindle speed signal with the sampling time. A current sensor is installed on the power supply line of the calender main drive motor. The current sensor reads the current of the calender main drive motor at each sampling moment, forming a real-time current signal of the calender main drive motor. A continuous sampling time axis is established based on the calender's timing reference. For each sampling time, the spindle speed in the calender spindle speed signal, the current in the real-time current signal of the calender main drive motor, the thickness in the real-time thickness profile sequence, and the conveying speed in the actual conveying speed of the shoe sole material are retrieved. The spindle speed, current, thickness, and conveying speed corresponding to the same sampling time are written into the same data record in a fixed order. Each data record represents the combination of the calender's operating state and the actual conveying state of the shoe sole material at the same moment. All data records are then arranged from earliest to latest according to the sampling time, thus establishing a state vector set.

[0013] S2: Determine whether the current calender is in a state of main machine shutdown, suspected material shortage, continuous material shortage, or normal output based on the state vector set. The data record corresponding to the current moment is located in the state vector set, and the spindle speed at the current moment is read from the spindle speed signal of the calender. The spindle speed represents the number of rotations completed by the calender spindle per unit time. When the spindle speed at the current moment is zero, it indicates that the calender spindle is not rotating at the current moment, and the main machine is stopped as the current operating condition. When the spindle speed at the current moment is greater than zero, it indicates that the calender spindle is rotating at the current moment. The real-time current signal of the calender main drive motor, the real-time thickness profile sequence, and the actual conveying speed of the sole material are read at the same current moment to determine whether the current moment belongs to the main machine stop condition.

[0014] In Siemens TIA Portal software, a working condition parameter table was established, and preset thresholds for suspected material shortage conveying speed, suspected material shortage thickness, and suspected material shortage current were set before the calender was put into operation. With these three thresholds set, the calender spindle speed and calendering process parameters were kept constant, and sole material was continuously supplied to the calender. The actual conveying speed, sampling point thickness, and real-time current of the calender main drive motor were collected during one rotation of the calender spindle. The minimum conveying speed, minimum sampling point thickness, and minimum current for the corresponding period were recorded as the lower limit of normal discharge conveying speed, the lower limit of normal discharge thickness, and the lower limit of normal discharge current, respectively. Subsequently, the supply of sole material to the calender was stopped while the calender spindle continued to rotate. When the thickness in the real-time thickness profile sequence equaled zero, the actual conveying speed, sampling point thickness, and real-time current of the calender main drive motor during one rotation of the calender spindle were collected again. The maximum conveying speed, maximum sampling point thickness, and maximum current for the corresponding period were recorded as the upper limit of no-material conveying speed, the upper limit of no-material thickness, and the upper limit of no-material current, respectively. The preset threshold values ​​for suspected material shortage conveying speed are: (lower limit of normal discharge conveying speed + upper limit of no-material conveying speed) / 2; preset threshold values ​​for suspected material shortage thickness are: (lower limit of normal discharge thickness + upper limit of no-material thickness) / 2; and preset threshold values ​​for suspected material shortage current are: (lower limit of normal discharge current + upper limit of no-material current) / 2. When the spindle speed is greater than zero at the current moment, the conveying speed, thickness, and current are read from the same state vector. If the current conveying speed is less than the preset threshold values ​​for suspected material shortage conveying speed, the current thickness is less than the preset threshold values ​​for suspected material shortage thickness, and the current current is less than the preset threshold values ​​for suspected material shortage current, the suspected material shortage condition is taken as the current condition. If the current conveying speed is greater than or equal to the preset threshold values ​​for suspected material shortage conveying speed, the current thickness is greater than or equal to the preset threshold values ​​for suspected material shortage thickness, or the current current is greater than or equal to the preset threshold values ​​for suspected material shortage current, the normal discharge condition is taken as the current condition. This determines whether the condition is suspected material shortage or normal discharge.

[0015] Once a suspected material shortage condition is established, the collected data saved during the three suspected material shortage threshold setting periods are used to set a preset time window duration parameter and corresponding judgment threshold. The moment when the supply of sole material stops is recorded as the material supply stop time, and the moment when the thickness in the real-time thickness profile sequence first equals zero is recorded as the material shortage start time. The preset time window duration parameter = material shortage start time - material supply stop time. A transition time window with a length equal to the preset time window duration parameter is selected starting from the material supply stop time, and a material shortage time window of the same length is selected starting from the material shortage start time. The calender spindle speed signal, the actual conveying speed of the sole material, and the real-time thickness profile sequence are read in the two time windows respectively. For the current time window used for judgment, the maximum spindle speed is extracted from the calender spindle speed signal, and the maximum conveying speed is extracted from the actual conveying speed of the sole material. The normalized spindle speed at each moment = spindle speed at each moment / maximum spindle speed. When the maximum conveying speed is greater than zero, the normalized conveying speed at each moment = conveying speed at each moment / maximum conveying speed. When the maximum conveying speed is equal to zero, the normalized conveying speed at each moment within the time window is recorded as zero. The slip ratio difference represents the difference between the calender spindle rotation ratio and the actual conveying ratio of the sole material. The slip ratio difference at each moment = normalized spindle speed at each moment - normalized conveying speed at the same moment. The slip integral value between two adjacent sampling moments = (slip ratio difference at the previous moment + slip ratio difference at the next moment) × (next sampling time - previous sampling time) / 2. The cumulative slip ratio integral = the sum of the slip integral values ​​of all adjacent sampling intervals within the time window. The preset fullness threshold is calculated as (minimum thickness during normal discharge + maximum thickness within the no-material time window) / 2. The preset slip ratio threshold is calculated as (maximum slip ratio difference during normal discharge + minimum slip ratio difference within the no-material time window) / 2. If the thickness at the current moment is less than the preset fullness threshold and the slip ratio difference at the current moment is greater than the preset slip ratio threshold, the time length between adjacent sampling moments is included in the abnormal state duration. If the thickness at the current moment is greater than or equal to the preset fullness threshold, or the slip ratio difference at the current moment is less than or equal to the preset slip ratio threshold, the corresponding time length is not included in the abnormal state duration. When the thickness at the current moment is zero, the time length between adjacent sampling moments is included in the no-material running duration. When the thickness at the current moment is greater than zero, the corresponding time length is not included in the no-material running duration. The abnormal state time duty cycle is calculated as: abnormal state duration / preset time window duration parameter, where the abnormal state time duty cycle represents the proportion of time occupied by the abnormal state within the entire time window.Calculate the cumulative slip ratio integral, the running time without materials, and the duty cycle of abnormal state time for the transition time window and the no-material time window respectively. The preset threshold for cumulative slip ratio integral is (cumulative slip ratio integral of transition time window + cumulative slip ratio integral of no-material time window) / 2. The preset threshold for no-material running time is (no-material running time of transition time window + no-material running time of no-material time window) / 2. The preset threshold for abnormal state time duty cycle is (abnormal state time duty cycle of transition time window + abnormal state time duty cycle of no-material time window) / 2. If the cumulative slip ratio integral within the current time window is greater than the preset cumulative slip ratio integral threshold, the running time without material is greater than the preset running time without material threshold, and the duty cycle of the abnormal state time is greater than the preset abnormal state time duty cycle threshold, the continuous material shortage condition will be taken as the current condition. If the cumulative slip ratio integral is less than or equal to the preset cumulative slip ratio integral threshold, the running time without material is less than or equal to the preset running time without material threshold, or the duty cycle of the abnormal state time is less than or equal to the preset abnormal state time duty cycle threshold, the suspected material shortage condition will continue to be taken as the current condition, thus obtaining the determination result of the continuous material shortage condition or the suspected material shortage condition.

[0016] S3: When the main machine is stopped, in normal material discharge mode, or in suspected material shortage mode, maintain the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor; when in continuous material shortage mode, control the receiving conveyor belt motor and the cooling line drive motor to standby mode. While in standby mode, if there is no residual material inside the cooling line and the continuous material shortage mode remains unchanged, control the receiving conveyor belt motor and the cooling line drive motor to stop, including: After determining the operating condition, the current operating frequencies of the receiving conveyor motor and the cooling line drive motor are read from the receiving conveyor motor driver and the cooling line drive motor driver, respectively. The current operating frequency represents the drive frequency received and maintained by the corresponding motor at the current moment. If the current operating condition is a main machine shutdown condition, a normal material discharge condition, or a suspected material shortage condition, the current operating frequency of the receiving conveyor motor and the current operating frequency of the cooling line drive motor are continuously written into the receiving conveyor motor driver and the cooling line drive motor driver, respectively, ensuring that both operating frequencies remain constant within the current control cycle. Subsequently, the calender spindle speed signal, the real-time current signal of the calender main drive motor, the shoe sole material thickness measurement data, and the continuous image sequence of the calender discharge surface are continuously collected according to the new sampling time. The spindle speed, current, thickness, and conveyor speed are then recombined according to the established common time reference, thereby obtaining the updated state vector set.

[0017] When a continuous material shortage condition is established, the standby frequency is first set. With the calender stopping feeding material and shoe sole material still present inside the cooling line, the frequency is gradually reduced from the current operating frequency of the receiving conveyor motor and the cooling line drive motor, according to the minimum frequency change that the motor driver can write. After each frequency reduction, the motor feedback frequency and the position of the shoe sole material inside the cooling line are continuously read at three sampling times. If the motor feedback frequency at all three sampling times is equal to the writing frequency, and the position of the shoe sole material inside the cooling line changes along the transmission direction at all three sampling times, the frequency is reduced by one more level. If any motor feedback frequency is not equal to the writing frequency, or the position of the shoe sole material inside the cooling line does not change, the previous frequency level is registered as the standby frequency. The graded load reduction control command indicates that the motor operating frequency is divided into multiple consecutive frequency levels from the current operating frequency and gradually adjusted to the standby frequency. The frequency difference of the receiving conveyor belt is calculated as follows: current operating frequency of the receiving conveyor belt motor - standby frequency. The frequency difference of the cooling line is calculated as: current operating frequency of the cooling line drive motor - standby frequency. The number of load reduction levels for the receiving conveyor belt is calculated as: frequency difference of the receiving conveyor belt / minimum frequency change that the motor driver can write. The number of load reduction levels for the cooling line is calculated as: frequency difference of the cooling line / minimum frequency change that the motor driver can write. The operating frequencies of the receiving conveyor belt motor and the cooling line drive motor are gradually adjusted to the standby frequency, decreasing by one frequency level per control cycle. A photoelectric sensor is installed at the cooling line inlet, and a rotary encoder is installed on the cooling line drive shaft. When the tail end of the sole material passes through the cooling line inlet, the photoelectric sensor records the corresponding moment. Starting from that moment, the cumulative movement distance of the sole material is obtained based on the cumulative revolutions of the rotary encoder and the circumference of the cooling line drive roller. The cumulative movement distance of the sole material = the number of revolutions of the drive roller corresponding to the rotary encoder × the circumference of the cooling line drive roller. The residual length of the material inside the cooling line = the transmission length from the cooling line inlet to the cooling line outlet - the cumulative movement distance of the sole material. Here, the residual length of the material inside the cooling line represents the length of the sole material still inside the cooling line from the tail end to the cooling line outlet. When the residual length of the material inside the cooling line is greater than zero or the continuous material shortage condition changes, the standby frequency continues to be written to the receiving conveyor motor and the cooling line drive motor. When the residual length of the material inside the cooling line is equal to zero and the continuous material shortage condition remains unchanged, the operating frequency of the receiving conveyor motor and the operating frequency of the cooling line drive motor are adjusted to zero. This yields the standby or shutdown control results for the receiving conveyor motor and the cooling line drive motor.

[0018] S4: When the receiving conveyor belt motor and the cooling line drive motor are in standby or stopped state, the following flags are determined based on the state vector set to maintain the material shortage condition or resume the material discharge condition: Once the current operating frequency of the receiving conveyor motor reaches the standby frequency, or after the operating frequencies of both the receiving conveyor motor and the cooling line drive motor are adjusted to zero, the real-time current signal of the calender main drive motor is sequentially read from the state vector set according to the sampling time. The current change rate represents the amplitude of the change in the current of the calender main drive motor within a unit sampling time. The current at the previous sampling time and the current at the current sampling time are selected sequentially. Current change = current at the current sampling time - current at the previous sampling time, sampling time interval = current sampling time - previous sampling time, and current change rate = current change / sampling time interval. When the current at the current sampling time is greater than the current at the previous sampling time, the current change rate is positive; when the current at the current sampling time is equal to the current at the previous sampling time, the current change rate is zero; when the current at the current sampling time is less than the current at the previous sampling time, the current change rate is negative. Thus, the current change rate of the real-time current signal of the calender main drive motor with sampling time is obtained.

[0019] Next, preset current recovery rate thresholds and preset fullness recovery thresholds are set. When the calender is in a continuous material shortage condition, the calender spindle is kept rotating, and the real-time current signal and real-time thickness profile sequence of the calender main drive motor are continuously read. The maximum current change rate obtained during one rotation of the calender spindle is recorded as the upper limit of the material shortage current change rate, and the maximum thickness obtained during the same period is recorded as the upper limit of the material shortage thickness. Subsequently, the supply of sole material to the calender is resumed. When the thickness in the real-time thickness profile sequence is greater than zero for the first time, the current change rate and thickness during one rotation of the calender spindle are read from the corresponding sampling time. The minimum current change rate obtained during the corresponding period is recorded as the lower limit of the recovery discharge current change rate, and the minimum thickness obtained during the corresponding period is recorded as the lower limit of the recovery discharge thickness. The preset current recovery rate threshold = (upper limit of material shortage current change rate + lower limit of recovery discharge current change rate) / 2, and the preset fullness recovery threshold = (upper limit of material shortage thickness + lower limit of recovery discharge thickness) / 2. The thickness at the current moment is extracted from the real-time thickness profile sequence in the state vector set, and the current change rate at the same current moment is called. If the current change rate at the current moment is less than or equal to the preset current recovery rate threshold, or the thickness at the current moment is less than or equal to the preset fullness recovery threshold, the material shortage condition determination flag is used as the current determination flag; if the current change rate at the current moment is greater than the preset current recovery rate threshold, and the thickness at the current moment is greater than the preset fullness recovery threshold, the material discharge condition determination flag is used as the current determination flag, thus obtaining the material shortage condition determination flag or the material discharge condition determination flag.

[0020] S5: When a "Maintain Material Shortage" condition determination flag is generated, maintain the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor; when a "Restore Discharge" condition determination flag is generated, adjust the operating speed of the receiving conveyor belt and the cooling line to synchronize them with the actual speed of the calender spindle at a fixed speed ratio, including: When the material shortage condition judgment flag is active, the current operating frequency of the receiving conveyor belt motor and the current operating frequency of the cooling line drive motor are read and written into the corresponding motor drivers. When the material discharge condition judgment flag is active again, during the period when the calender spindle stops rotating, a flexible length measuring ruler is used to circumferentially around the outer perimeter of the calender spindle roller. The length corresponding to the overlapping position of the first and last ends of the flexible length measuring ruler is read and recorded as the circumference of the calender spindle roller. The circumference of the calender spindle roller represents the actual distance traveled by the outer perimeter of the roller during one rotation of the calender spindle roller. The spindle speed reference value is the maximum spindle speed collected during the continuous normal supply of shoe sole material during the three suspected material shortage threshold setting periods. The normalized calender spindle speed signal = current spindle speed / spindle speed reference value, where the normalized calender spindle speed signal represents the proportion of the current spindle speed relative to the spindle speed reference value. Initial receiving speed = normalized calender spindle speed signal × spindle speed reference value × circumference of calender spindle roller. The initial receiving speed is calculated according to the time unit used by the receiving conveyor belt drive motor, and the converted initial receiving speed is written into the receiving conveyor belt drive motor, thus obtaining the initial receiving speed of the receiving conveyor belt drive motor.

[0021] After the receiving conveyor belt drive motor runs at the initial receiving speed, the real-time load current of the receiving motor is continuously collected by a current sensor installed on the power supply line of the receiving motor, and the current load current is read from the real-time load current of the receiving motor at the current sampling time. The fixed speed ratio represents the constant numerical ratio between the actual running speed of the receiving conveyor belt or the actual running speed of the cooling line and the actual rotation speed of the calender spindle. The fixed speed ratio is set during normal discharge conditions. The actual running speed of the receiving conveyor belt, the actual running speed of the cooling line, and the actual rotation speed of the calender spindle are continuously read during one rotation of the calender spindle. The fixed speed ratio of the receiving conveyor belt = the average actual running speed of the receiving conveyor belt during one rotation of the calender spindle / the average actual rotation speed of the calender spindle. The fixed speed ratio of the cooling line = the average actual running speed of the cooling line during one rotation of the calender spindle / the average actual rotation speed of the calender spindle. When the ratio of the actual operating speed of the receiving conveyor belt to the actual rotational speed of the calender spindle is equal to the fixed speed ratio of the receiving conveyor belt, and the ratio of the actual operating speed of the cooling line to the actual rotational speed of the calender spindle is equal to the fixed speed ratio of the cooling line, the corresponding operating state is designated as the fixed speed ratio synchronous operating state. During the fixed speed ratio synchronous operating state, the real-time load current of multiple adjacent receiving motors is extracted according to the continuous sampling time. The stable operating load current = the sum of multiple continuous load currents / the number of continuous load currents, where the stable operating load current represents the average value of the load current corresponding to multiple continuous sampling times during the fixed speed ratio synchronous operating state. The load current fluctuation deviation = the current load current - the stable operating load current, where the load current fluctuation deviation represents the direction and value of the deviation of the current load current relative to the stable operating load current. When setting the speed adjustment conversion coefficient, in the fixed speed ratio synchronous operating state, the actual operating speed of the receiving conveyor belt is reduced and increased in stages according to the minimum speed change that the receiving conveyor belt drive motor can write. After each change, the actual operating speed of the receiving conveyor belt before and after the change and the corresponding real-time load current of the receiving motor are recorded. Each speed change = actual operating speed of the receiving conveyor belt after the change - actual operating speed of the receiving conveyor belt before the change; each load current fluctuation deviation = real-time load current of the receiving motor after the change - real-time load current of the receiving motor before the change; each proportional coefficient = speed change / load current fluctuation deviation; speed adjustment conversion coefficient = sum of all proportional coefficients / number of proportional coefficients, where the speed adjustment conversion coefficient represents the speed adjustment value corresponding to each unit change in load current. Compensation speed adjustment amount = load current fluctuation deviation × speed adjustment conversion coefficient; actual operating speed of the receiving conveyor belt = initial receiving speed + compensation speed adjustment amount; actual operating speed of the cooling line = initial receiving speed + compensation speed adjustment amount. Thus, the actual operating speeds of the receiving conveyor belt and the cooling line are obtained.

[0022] Finally, the normalized calender spindle speed signal and spindle speed reference value are retrieved. The actual calender spindle speed = normalized calender spindle speed signal × spindle speed reference value. The pre-set fixed speed ratios of the receiving conveyor belt and cooling line are read. The target running speed of the receiving conveyor belt = actual calender spindle speed × fixed speed ratio of the receiving conveyor belt, and the target running speed of the cooling line = actual calender spindle speed × fixed speed ratio of the cooling line. When the actual running speed of the receiving conveyor belt is greater than the target running speed, the actual running speed of the receiving conveyor belt is reduced until it reaches the target running speed. When the actual running speed of the receiving conveyor belt is less than the target running speed, the actual running speed is increased until it reaches the target running speed. When the actual running speed of the receiving conveyor belt is equal to the target running speed, the actual running speed is maintained. When the actual operating speed of the cooling line is greater than the target operating speed, the actual operating speed is reduced until it reaches the target speed. When the actual operating speed is less than the target speed, the actual operating speed is increased until it reaches the target speed. When the actual operating speed equals the target speed, the actual operating speed is maintained. The actual rotational speed of the calender spindle is continuously updated according to the new sampling time, and the target operating speeds of the receiving conveyor belt and the cooling line are updated synchronously. This ensures that the actual operating speed of the receiving conveyor belt maintains a fixed speed ratio with the actual rotational speed of the calender spindle, and the actual operating speed of the cooling line maintains a fixed speed ratio with the actual rotational speed of the calender spindle. This yields the process control results.

[0023] Please see Figure 3 A process control system for a shoe sole material production line, the system comprising: The vector set construction module obtains a state vector set representing the operating state of the calender and the actual conveying state of the sole material; wherein, the state vector set includes the calender spindle speed signal, the real-time current signal of the calender main drive motor, the real-time thickness profile sequence, and the actual conveying speed of the sole material; The working condition determination module determines whether the current calender is in a main machine shutdown condition, a suspected material shortage condition, a continuous material shortage condition, or a normal material discharge condition based on the state vector set. The equipment control module maintains the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor when the main machine is stopped, the material is being discharged normally, or the material shortage is suspected. When the material shortage is continuous, the receiving conveyor belt motor and the cooling line drive motor are put into standby mode. When in standby mode, if there is no residual material inside the cooling line and the continuous material shortage condition does not change, the receiving conveyor belt motor and the cooling line drive motor are stopped. The recovery determination module determines whether to maintain the material shortage condition determination flag or restore the material discharge condition determination flag based on the state vector set when the material receiving conveyor belt motor and the cooling line drive motor are in standby or stopped state. The synchronization control module maintains the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor when a material shortage condition judgment flag is generated; when a material discharge condition judgment flag is generated, it adjusts the operating speed of the receiving conveyor belt and the cooling line to synchronize them with the actual speed of the calender spindle at a fixed speed ratio.

[0024] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for controlling the operation of a shoe sole material production line, characterized in that, Includes the following steps: Obtain a state vector set characterizing the operating state of the calender and the actual conveying state of the sole material; wherein, the state vector set includes the calender spindle speed signal, the real-time current signal of the calender main drive motor, the real-time thickness profile sequence, and the actual conveying speed of the sole material; Based on the state vector set, determine whether the current calender is in a main machine shutdown state, a suspected material shortage state, a continuous material shortage state, or a normal material discharge state; When the main machine is stopped, in normal material discharge mode, or in suspected material shortage mode, maintain the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor; when in continuous material shortage mode, control the receiving conveyor belt motor and the cooling line drive motor to standby mode. When in standby mode, if there is no residual material inside the cooling line and the continuous material shortage mode does not change, control the receiving conveyor belt motor and the cooling line drive motor to stop. When the receiving conveyor belt motor and the cooling line drive motor are in standby or stopped state, the state vector set determines the judgment flag for maintaining the material shortage condition or the judgment flag for resuming the material discharge condition. When a "Maintain Material Shortage" condition determination flag is generated, maintain the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor; when a "Restore Discharge" condition determination flag is generated, adjust the operating speed of the receiving conveyor belt and the cooling line to synchronize them with the actual speed of the calender spindle at a fixed speed ratio.

2. The method for controlling the operation of a shoe sole material production line according to claim 1, characterized in that, The state vector set used to acquire the operating state of the calender and the actual conveying state of the shoe sole material includes: During the calendering and unloading process of the sole material, the thickness measurement data of the sole material and the sampling time of the calendering and unloading process are obtained. The thickness of each sampling point in the sole material thickness measurement data is extracted along the sole material transport direction. The thicknesses of each sampling point are arranged in the order of the sampling time to generate a real-time thickness profile sequence. A continuous image sequence of the calendered material output surface is acquired. The surface texture edge pixel coordinates within adjacent image frames in the continuous image sequence of the calendered material output surface are extracted. The rate of change of the surface texture edge pixel coordinates with the sampling time is calculated to obtain the pixel movement speed. The camera calibration coefficient is acquired. The product of the pixel movement speed and the camera calibration coefficient is calculated to obtain the actual conveying speed of the shoe sole material. The main spindle speed signal of the calender and the real-time current signal of the main drive motor of the calender are acquired. The main spindle speed signal of the calender, the real-time current signal of the main drive motor of the calender, the real-time thickness profile sequence and the actual conveying speed of the sole material are aligned according to the time reference to establish a state vector set.

3. The method for controlling the operation of a shoe sole material production line according to claim 2, characterized in that, The process of determining whether the current calender is in a main machine shutdown state, a suspected material shortage state, a continuous material shortage state, or a normal material discharge state based on the state vector set includes: The calender spindle speed signal is obtained from the state vector set. The calender spindle speed signal includes the spindle speed at each moment. When the spindle speed is zero at the current moment, the main machine shutdown condition is generated. When the spindle speed is greater than zero at the current moment, the real-time current signal of the calender main drive motor, the real-time thickness profile sequence, and the actual conveying speed of the sole material are acquired from the state vector set. The real-time current signal of the calender main drive motor includes the current at each moment, the real-time thickness profile sequence includes the thickness at each moment, and the actual conveying speed of the sole material includes the conveying speed at each moment. A suspected material shortage condition is generated when the conveying speed at the current moment is less than a preset suspected material shortage conveying speed threshold, the thickness at the current moment is less than a preset suspected material shortage thickness threshold, and the current at the current moment is less than a preset suspected material shortage current threshold. A normal material discharge condition is generated when the conveying speed at the current moment is greater than or equal to the preset suspected material shortage conveying speed threshold, the thickness at the current moment is greater than or equal to the preset suspected material shortage thickness threshold, or the current at the current moment is greater than or equal to the preset suspected material shortage current threshold. When the suspected material shortage condition is generated, the calender spindle speed signal and the actual conveying speed of the sole material are normalized respectively. The difference between the normalized spindle speed and the normalized conveying speed at each moment is calculated to obtain the slip ratio difference at each moment. The cumulative slip ratio integral is obtained by integrating the slip ratio difference at each moment with the sampling time. The state where the thickness at the current moment is less than the preset fullness threshold and the slip ratio difference at the current moment is greater than the preset slip ratio threshold is regarded as an abnormal state. The duration of the abnormal state is accumulated within the time window corresponding to the preset time window duration parameter to obtain the abnormal state duration. The state where the thickness at the current moment is equal to zero is regarded as no material conveying. In the operation state, the duration of the material-free operation state is accumulated within the time window to obtain the material-free operation time. The ratio of the abnormal state duration to the preset time window duration parameter is calculated to obtain the abnormal state time duty cycle. When the cumulative slip ratio integral is greater than the preset cumulative slip ratio integral threshold, the material-free operation time length is greater than the preset material-free operation time threshold, and the abnormal state time duty cycle is greater than the preset abnormal state time duty cycle threshold, the operation is switched to continuous material shortage condition. When the cumulative slip ratio integral is less than or equal to the preset cumulative slip ratio integral threshold, the material-free operation time is less than or equal to the preset material-free operation time threshold, or the abnormal state time duty cycle is less than or equal to the preset abnormal state time duty cycle threshold, the operation is maintained as suspected material shortage condition.

4. The method for controlling the operation of a shoe sole material production line according to claim 3, characterized in that, When the main machine is stopped, in normal material discharge mode, or in suspected material shortage mode, the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor is maintained; when the material shortage mode is continuous, the receiving conveyor belt motor and the cooling line drive motor are controlled to standby mode. During standby, if there is no residual material inside the cooling line and the continuous material shortage mode remains unchanged, the receiving conveyor belt motor and the cooling line drive motor are controlled to stop. When the host shutdown condition, the normal material discharge condition, or the suspected material shortage condition is generated, the current operating frequency of the receiving conveyor belt motor and the current operating frequency of the cooling line drive motor are maintained, and the state vector set is re-established. When the continuous material shortage condition is generated, a graded load reduction control command is generated. The current operating frequency of the receiving conveyor motor, the current operating frequency of the cooling line drive motor, and the standby frequency are obtained. Based on the graded load reduction control command, the current operating frequencies of the receiving conveyor motor and the cooling line drive motor are adjusted to the standby frequency to control the receiving conveyor motor and the cooling line drive motor to standby. The residual length of material inside the cooling line is obtained, and it is determined whether the residual length of material inside the cooling line is equal to zero and whether the continuous material shortage condition remains unchanged. When the residual length of material inside the cooling line is greater than zero or the continuous material shortage condition changes, the standby frequency is maintained. When the residual length of material inside the cooling line is equal to zero and the continuous material shortage condition remains unchanged, a complete shutdown control command is generated. Based on the complete shutdown control command, the current operating frequencies of the receiving conveyor motor and the cooling line drive motor are adjusted to zero to control the receiving conveyor motor and the cooling line drive motor to stop.

5. The method for controlling the operation of a shoe sole material production line according to claim 4, characterized in that, When the receiving conveyor belt motor and the cooling line drive motor are in standby or stopped states, the determination of the maintaining material shortage condition judgment flag or the resuming material discharge condition judgment flag based on the state vector set includes: While the current operating frequency of the receiving conveyor belt motor is at the standby state frequency or during the execution of the complete shutdown control command, the real-time current signal of the calender main drive motor in the state vector set is read, and the rate of change of the real-time current signal of the calender main drive motor with the sampling time is calculated. Extract the thickness at the current moment from the real-time thickness profile sequence in the state vector set. When the current change rate at the current moment is less than or equal to a preset current recovery rate threshold or the thickness at the current moment is less than or equal to a preset fullness recovery threshold, generate a material shortage condition determination flag. When the current change rate at the current moment is greater than the preset current recovery rate threshold and the thickness at the current moment is greater than the preset fullness recovery threshold, generate a material discharge condition determination flag.

6. The method for controlling the operation of a shoe sole material production line according to claim 5, characterized in that, The step of maintaining the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor when a material shortage condition determination flag is generated, and adjusting the operating speed of the receiving conveyor belt and the cooling line to synchronize with the actual speed of the calender spindle at a fixed speed ratio when a material discharge condition determination flag is generated, includes: When the "Maintain Material Shortage" determination flag is generated, the current operating frequency of the receiving conveyor belt motor and the current operating frequency of the cooling line drive motor are maintained. When the "Restore Discharge" determination flag is generated, the circumference of the calender spindle roller and the reference value of the spindle speed are obtained. The calender spindle speed signal in the state vector set is extracted and normalized. The product of the normalized calender spindle speed signal, the reference value of the spindle speed, and the circumference of the calender spindle roller is calculated to obtain the initial receiving speed. The initial receiving speed is then sent to the receiving conveyor belt drive motor. During the operation of the receiving conveyor belt drive motor, the real-time load current of the receiving motor is obtained, the current load current corresponding to the real-time load current of the receiving motor is extracted, the stable operation load current is obtained, the difference between the current load current and the stable operation load current is calculated to obtain the load current fluctuation deviation, the speed adjustment conversion coefficient is obtained, the product of the load current fluctuation deviation and the speed adjustment conversion coefficient is calculated to obtain the compensation speed adjustment amount, and the initial receiving speed and the compensation speed adjustment amount are summed to calculate the actual operating speed of the receiving conveyor belt and the actual operating speed of the cooling line. The actual spindle speed of the calender is obtained by multiplying the normalized spindle speed signal of the calender with the spindle speed reference value. The actual operating speed of the receiving conveyor belt and the actual operating speed of the cooling line are configured to operate synchronously with the actual spindle speed of the calender at a fixed speed ratio, and the process control results are obtained.

7. The method for controlling the operation of a shoe sole material production line according to claim 2, characterized in that, The camera calibration coefficient is determined by selecting two calibration points with known actual distance within the camera's field of view, obtaining the pixel distance between the two calibration points in the image, and determining the ratio of the actual distance to the pixel distance as the camera calibration coefficient.

8. The method for controlling the operation of a shoe sole material production line according to claim 6, characterized in that, The stable operating load current is specifically the current obtained by averaging multiple continuous load currents corresponding to the real-time load current of the receiving motor during the period when the actual operating speed of the receiving conveyor belt, the actual operating speed of the cooling line, and the actual speed of the calender spindle are in a state of synchronous operation with a fixed speed ratio.

9. The method for controlling the operation of a shoe sole material production line according to claim 6, characterized in that, The speed adjustment conversion coefficient is a proportional coefficient obtained by averaging the ratio of the speed change to the corresponding load current fluctuation deviation in each step of the actual running speed of the receiving conveyor belt under the fixed speed ratio synchronous operation state.

10. A process control system for a shoe sole material production line, characterized in that, The system includes: The vector set construction module obtains a state vector set representing the operating state of the calender and the actual conveying state of the sole material; wherein, the state vector set includes the calender spindle speed signal, the real-time current signal of the calender main drive motor, the real-time thickness profile sequence, and the actual conveying speed of the sole material; The working condition determination module determines whether the current calender is in a main machine shutdown condition, a suspected material shortage condition, a continuous material shortage condition, or a normal material discharge condition based on the state vector set. The equipment control module maintains the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor when the main machine is stopped, the material is being discharged normally, or the material shortage is suspected. When the material shortage is continuous, the receiving conveyor belt motor and the cooling line drive motor are put into standby mode. When in standby mode, if there is no residual material inside the cooling line and the continuous material shortage condition does not change, the receiving conveyor belt motor and the cooling line drive motor are stopped. The recovery determination module determines whether to maintain the material shortage condition determination flag or restore the material discharge condition determination flag based on the state vector set when the material receiving conveyor belt motor and the cooling line drive motor are in standby or stopped state. The synchronization control module maintains the current operating frequency of the receiving conveyor belt motor and the cooling line drive motor when a material shortage condition judgment flag is generated; when a material discharge condition judgment flag is generated, it adjusts the operating speed of the receiving conveyor belt and the cooling line to synchronize them with the actual speed of the calender spindle at a fixed speed ratio.

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