A traction motor control system for a PE hose production line

Abstract

This invention relates to the field of hose processing technology, specifically disclosing a traction motor control system for a PE hose production line. The system includes a traction module comprising an upper traction roller, a lower traction roller, and a traction frequency converter. By combining constant traction speed control with dynamic adjustment of feeding speed, it effectively solves the tension fluctuation problem caused by uneven feeding during PE hose production. The introduction of a laser rangefinder sensor enables non-contact, high-precision monitoring of material sag, avoiding the defects of traditional mechanical tension rollers such as easy wear and slow response. The closed-loop adjustment mechanism of the feeding servo motor speed adjusted in real time by a PID controller can quickly respond to disturbances, ensuring that the distance between the PE material and the ground is always maintained within the process requirements. This ensures uniform hose wall thickness and smooth surface, reduces scrap rate, and significantly improves the automation level and operational stability of the production line.

Description

Technical Field

[0001] This invention relates to the field of hose processing technology, specifically to a traction motor control system for a PE hose production line. Background Technology

[0002] Due to its excellent flexibility, corrosion resistance and low cost, PE hoses are widely used in agricultural irrigation, medical infusion, pneumatic pipelines, cable sheaths and other fields. In the continuous extrusion production process of PE hoses, the speed coordination control between the traction device and the feeding device is the key technology to ensure uniform pipe wall thickness, consistent outer diameter and surface quality.

[0003] In traditional PE hose production lines, the speed coordination control between the traction device and the feeding device is achieved as follows: the analog output of the traction inverter is directly connected in parallel to the analog input of the feeding inverter, and a fixed proportional coefficient is set. Based on this, when the traction speed changes, the feeding speed changes synchronously according to a fixed ratio, thereby realizing closed-loop control of the feeding motor and ensuring that the speed of the feeding motor can be adapted to the traction speed of the PE hose.

[0004] In the existing technology, the speed coordination control between the traditional traction device and the feeding device is based on a fixed proportional coefficient to control the speed of the feeding motor. However, in the actual production process, the actual feeding linear speed is affected by the reel radius. Based on this, adjusting the feeding motor speed based on a fixed proportional coefficient will result in the inability to compensate for the linear speed difference caused by the diameter change, thereby reducing the production quality of PE material. Summary of the Invention

[0005] The purpose of this invention is to provide a traction motor control system for a PE hose production line, solving the following technical problems: How to optimize the speed control method of the traction motor in a PE hose production line.

[0006] The objective of this invention can be achieved through the following technical solutions: A traction motor control system for a PE hose production line, the system comprising: The traction module includes an upper traction roller, a lower traction roller, and a traction inverter. The traction inverter is electrically connected to the upper traction roller and the lower traction roller and is used to traction the PE hose at a set constant speed. The feeding module comprises a feeding servo motor and a feeding roller, wherein the feeding servo motor and the feeding roller are electrically connected and used to release PE material. The control module, including a PID controller, is connected to the laser rangefinder and the feeding servo motor to adjust the speed of the feeding servo motor. The laser ranging module, including a laser ranging sensor, is installed between the traction module and the feeding module to measure the distance of the PE material from the ground in real time. The real-time adjustment module outputs a constant speed control signal to the traction module through the traction frequency converter to pull the PE hose at a set constant speed. Combined with the deviation between the ground distance and the preset ground distance fed back by the laser ranging module in real time, the speed of the feeding servo motor is adjusted in real time through the PID controller. The anomaly detection module is used to automatically stop the output of the traction inverter and issue an audible and visual alarm when the laser rangefinder detects that the distance from the ground exceeds the preset distance by 5 seconds.

[0007] Furthermore, the traction inverter adopts a closed-loop speed control mode to ensure that the traction speed fluctuation does not exceed ±0.5%.

[0008] Furthermore, the adjustment process of the real-time adjustment module includes: Through formula Calculate the feedback control component of the PID controller at time t. ; Where t is the current time point, The deviation of the distance from the ground at time t As a dummy element in time integration, The cumulative integral is the deviation from the start time to time t. The first time derivative of the deviation. This is the proportional gain coefficient. This is the integral gain coefficient. This is the differential gain coefficient.

[0009] Furthermore, the adjustment process of the real-time adjustment module also includes: The feeding servo motor is equipped with an encoder feedback module, and the PID controller combines the encoder feedback signal and the laser ranging signal to achieve feedforward and feedback composite control, including: Through formula Calculate the feedforward control component of the PID controller at time t. ; Through formula The output PID controller calculates the command signal at time t and sends it to the unloading servo motor driver. ; in, This is the feedforward gain coefficient. This represents the traction speed output by the traction inverter at time t.

[0010] Furthermore, the adjustment process of the real-time adjustment module also includes: The PID controller combines the command signal calculated at time t and sent to the feeding servo motor driver. It outputs the corresponding current and voltage to drive the feeding servo motor to rotate at the target speed.

[0011] Furthermore, the adjustment process of the real-time adjustment module also includes: After the speed of the unloading servo motor is adjusted, the traction speed, ground clearance and unloading servo motor speed data are recorded at intervals of no less than 1 second, and exported to an external storage device via a network interface.

[0012] Furthermore, the PID controller includes an anti-integral saturation unit: when When this happens, the integral term stops accumulating and the integral state is reset according to the following formula: in, The preset deviation threshold value, This is the moment when the last deviation enters the threshold range.

[0013] Furthermore, the detection process of the anomaly detection module includes: The human-machine interface displays the current ground clearance, traction speed, feed motor speed and PID output value in real time. It also supports operators to modify the preset ground clearance and PID parameters online. When the laser rangefinder detects that the ground clearance exceeds the preset ground clearance for 5 seconds, it automatically stops the output of the traction frequency converter and issues an audible and visual alarm.

[0014] The beneficial effects of this invention are: (1) By combining constant control of traction speed with dynamic adjustment of feeding speed, this invention effectively solves the problem of tension fluctuation caused by uneven feeding during the production of PE hoses. The introduction of laser rangefinder sensor realizes non-contact, high-precision material sag monitoring, avoiding the defects of easy wear and slow response of traditional mechanical tension roller. The closed-loop adjustment mechanism of adjusting the speed of feeding servo motor in real time through PID controller can quickly respond to disturbances, so that the distance of PE material from the ground is always maintained within the range of process requirements, thereby ensuring uniform hose wall thickness and smooth surface, reducing scrap rate, and significantly improving the automation level and operation stability of production line.

[0015] (2) This invention introduces feedforward control, which directly calculates the compensation amount of the feeding motor using the traction speed signal. This is equivalent to "informing" the feeding system in advance of the changes that are about to occur, thus achieving synchronous following. On this basis, the composite control method combines the speed of feedforward with the robustness of feedback: feedforward ensures speed tracking, and feedback eliminates residual errors and environmental disturbances. On this basis, the speed control method of the traction motor of the PE hose production line can be optimized to ensure the rationality of the control result. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic block diagram of a traction motor control system for a PE hose production line according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1 As shown, in one embodiment, this application provides a traction motor control system for a PE hose production line, the system comprising: The traction module includes an upper traction roller, a lower traction roller, and a traction inverter. The traction inverter is electrically connected to the upper traction roller and the lower traction roller and is used to traction the PE hose at a set constant speed. The feeding module comprises a feeding servo motor and a feeding roller, wherein the feeding servo motor and the feeding roller are electrically connected and used to release PE material. The control module, including a PID controller, is connected to the laser rangefinder and the feeding servo motor to adjust the speed of the feeding servo motor. The laser ranging module, including a laser ranging sensor, is installed between the traction module and the feeding module to measure the distance of the PE material from the ground in real time. The real-time adjustment module outputs a constant speed control signal to the traction module through the traction frequency converter to pull the PE hose at a set constant speed. Combined with the deviation between the ground distance and the preset ground distance fed back by the laser ranging module in real time, the speed of the feeding servo motor is adjusted in real time through the PID controller. The anomaly detection module is used to automatically stop the output of the traction inverter and issue an audible and visual alarm when the laser ranging sensor detects that the distance from the ground exceeds the preset distance from the ground by 5 seconds. Through the above technical solution, this embodiment provides a traction motor control system for a PE hose production line. The system includes a traction module, a feeding module, a control module, a laser ranging module, a real-time adjustment module, and an anomaly detection module that work together. The traction inverter drives the upper and lower traction rollers to pull the PE hose at a constant speed. The laser ranging sensor measures the distance of the PE material from the ground in real time. The PID controller dynamically adjusts the speed of the feeding servo motor according to the deviation between the actual distance from the ground and the preset value, thereby maintaining the stable tension of the PE material. When the distance from the ground exceeds the safe range for 5 seconds, the anomaly detection module stops traction and alarms. By combining constant traction speed control with dynamic adjustment of feeding speed, the tension fluctuation problem caused by uneven feeding during PE hose production is effectively solved. The introduction of laser rangefinders enables non-contact, high-precision monitoring of material sag, avoiding the defects of traditional mechanical tension rollers that are prone to wear and slow response. The closed-loop adjustment mechanism of the feeding servo motor speed adjusted in real time by the PID controller can quickly respond to disturbances, keeping the distance between the PE material and the ground within the range required by the process. This ensures uniform hose wall thickness and smooth surface, reduces scrap rate, and significantly improves the automation level and operational stability of the production line.

[0020] Furthermore, the traction inverter adopts a closed-loop speed control mode to ensure that the traction speed fluctuation does not exceed ±0.5%; Through the above technical solution, this embodiment provides a control mode for the traction inverter. The traction inverter adopts a closed-loop speed control mode, which uses a built-in encoder or tachogenerator to provide real-time feedback on the actual motor speed. After comparing it with the set value, the output frequency is automatically adjusted to keep the traction speed fluctuation within ±0.5%, ensuring the uniformity of the traction process. High-precision speed control is especially suitable for occasions with strict requirements on pipe wall thickness tolerance. At the same time, the stable traction speed provides a reliable time reference for subsequent processes such as cutting, winding, and packaging. During implementation, the encoder selection and inverter parameter tuning (proportional gain, integral time) need to be optimized according to the actual load inertia. In addition, the closed-loop control can automatically compensate for speed drift caused by factors such as motor heating and grid voltage fluctuations, significantly improving the system's anti-interference capability.

[0021] Furthermore, the adjustment process of the real-time adjustment module includes: Through formula Calculate the feedback control component of the PID controller at time t. ; Where t is the current time point, Let be the deviation of the ground distance at time t. , The preset ground clearance for PE material. This represents the distance of the PE material above the ground measured in real time by the laser rangefinder at time t. As a dummy element in time integration, The cumulative integral is the deviation from the start time to time t. The first time derivative of the deviation can be expressed by the formula Calculated, where, For time increments, For future time deviation, For limit operators, This is the proportional gain coefficient. This is the integral gain coefficient. The differential gain coefficient, , and These are control coefficients with corresponding dimensions, ensuring that the calculated results of the proportional, integral, and differential terms have the same dimensions, and are all control signals. The dimensions are known, thus enabling direct addition operations; Through the above technical solution, this embodiment provides the feedback control component of the PID controller at time t. It can be done through the formula The calculations show that the proportional term quickly responds to the current deviation, the integral term eliminates steady-state errors, and the derivative term predicts the trend of deviation changes. These three terms are superimposed after their dimensions are unified, achieving precise speed control of the feeding servo motor. This configuration introduces a complete proportional, integral, and derivative structure into the PID control algorithm, explicitly requiring unified dimensions for all three terms. This is crucial for achieving precise and stable control. The proportional term ensures the system's rapid response to deviations; for example, when the PE material suddenly sags, the feeding motor can accelerate quickly. The integral term eliminates long-term steady-state errors caused by friction, load changes, etc., ensuring the ground clearance is precisely equal to the set value. The derivative term plays a "predictive" adjustment role, suppressing system overshoot and oscillations. It is particularly suitable for nonlinear processes where the feeding roll diameter gradually decreases and the moment of inertia changes, thereby improving the rationality and accuracy of the PID controller's subsequent adjustments to the servo motor speed. It should be noted that, for , and The parameters can be tuned using the following method: First, set... , ,Will Gradually increase the gain from 0 until the distance from the ground exhibits a small, constant-amplitude oscillation; record the critical gain at this point. and oscillation cycle Then, based on the empirical formula of the Ziegler-Nichols tuning method, the following settings were made: , , Furthermore, for thinner and softer PE pipes, the proportional gain should be... Reduce by 20% to decrease system response sensitivity and avoid tension overshoot; for producing thicker or stiffer PE pipes, the proportional gain should be adjusted. Increase by 10 percent to enhance the system's ability to eliminate steady-state errors.

[0022] Furthermore, the adjustment process of the real-time adjustment module also includes: The feeding servo motor is equipped with an encoder feedback module, and the PID controller combines the encoder feedback signal and the laser ranging signal to achieve feedforward and feedback composite control, including: Through formula Calculate the feedforward control component of the PID controller at time t. ; Through formula The output PID controller calculates the command signal at time t and sends it to the unloading servo motor driver. ; in, is the feedforward gain coefficient, a dimensionless coefficient used to convert the traction speed into a compensation amount for the unloading motor. Let t be the traction speed output by the traction inverter at time t; Through the above technical solution, this embodiment provides a command signal calculated by the controller at time t and sent to the feeding servo motor driver. The traction speed signal is used as a feedforward input and is directly superimposed on the PID feedback control quantity, so that the speed of the feeding motor responds to the change of traction speed in advance, reducing the lag of feedback adjustment. With this setup, traditional pure feedback PID control can only start adjusting after a deviation occurs, resulting in inherent lag. In a PE hose production line, the traction speed may change frequently due to process requirements. If the feeding motor response lags, it will inevitably lead to sudden changes in PE material tension, and even "stringing" or "material piling". By introducing feedforward control, the feedforward control directly calculates the compensation amount of the feeding motor using the traction speed signal, which is equivalent to "informing" the feeding system of the changes that are about to occur, and achieving synchronous following. On this basis, the composite control method combines the speed of feedforward with the robustness of feedback: feedforward ensures speed tracking, and feedback eliminates residual errors and environmental disturbances. Based on this, the speed control method of the traction motor in the PE hose production line can be optimized to ensure the rationality of the control results. It should be noted that the feedforward gain coefficient The initial value can be set as k4 = (maximum radius of the unloading drum / circumference of the traction wheel) Reduction ratio.

[0023] Furthermore, the adjustment process of the real-time adjustment module also includes: The PID controller combines the command signal calculated at time t and sent to the feeding servo motor driver. The corresponding current and voltage are output to drive the feeding servo motor to rotate at the target speed. Through the above technical solution, this embodiment provides the adjustment process of the real-time adjustment module and the command signal output by the PID controller. After being limited and smoothed, the signal is converted into corresponding current and voltage by the driver, driving the servo motor to rotate at the target speed, thus realizing the execution of control commands into mechanical actions. In actual engineering, the accuracy and linearity of the control signal and the response bandwidth of the driver directly affect the final control effect. By requiring the driver to output "corresponding current and voltage", this system emphasizes the vector control or direct torque control capability of the servo driver, which can automatically adjust the current according to the load torque, so that the motor outputs sufficient torque to pull the PE material. This design makes the control system very versatile. As long as the driver supports analog or digital speed commands, it can be adapted to feeding servo motors of different brands and power, which facilitates equipment upgrades and maintenance.

[0024] Furthermore, the adjustment process of the real-time adjustment module also includes: After the speed of the unloading servo motor is adjusted, the traction speed, ground clearance and unloading servo motor speed data are recorded at intervals of no less than 1 second, and exported to an external storage device through the network interface; Through the above technical solution, this embodiment records the traction speed, ground clearance, and servo motor speed data at intervals of no less than 1 second after the servo motor speed adjustment is completed. The data is then exported to an external storage device via a network interface. This setup makes the data recording and export function the foundation for intelligent manufacturing and lean production. In the continuous production of PE hoses, the system can fully capture tension fluctuations, the servo motor response process, and ground clearance change curves by recording once per second, providing quantitative basis for process optimization and fault diagnosis. For example, when the finished pipe has uneven wall thickness, engineers can replay the data to check whether the traction speed is stable and whether the PID is over-adjusted during that period. At the same time, the network interface supports remote monitoring, allowing managers to view the operating status of multiple production lines in real time from the office, achieving centralized management. Overall, this function greatly improves the system's informatization level and maintainability.

[0025] Furthermore, the PID controller includes an anti-integral saturation unit: when When this happens, the integral term stops accumulating and the integral state is reset according to the following formula: in, The preset deviation threshold value, The moment when the last deviation enters the threshold range; Through the above technical solution, this embodiment provides a process for stopping the accumulation of the integral term. When the absolute value of the deviation exceeds the threshold, the anti-integral saturation unit suspends the accumulation of the integral term and freezes the integral state at the moment when the last deviation entered the threshold range, preventing control lag and overshoot caused by long-term saturation. When the deviation is large for a long time (such as severe PE material sagging during startup), the integral term will continue to accumulate, causing the control quantity to far exceed the actual capacity of the motor. Even if the deviation has decreased, the integral term still maintains a large value, causing severe overshoot and long-term oscillation. Claim 7 introduces an anti-integral saturation unit to immediately freeze the integral accumulation when the deviation exceeds a preset threshold (such as 0.1m), avoiding "integral overload". This mechanism significantly improves the dynamic performance of the system under large disturbances. On a PE hose production line, typical integral saturation scenarios include: the startup feeding stage, after changing the unloading reel, and after abnormal shutdown recovery. After adopting this technology, the unloading motor starts smoothly, and the distance from the ground can smoothly enter the set range without overshoot or repeated adjustments, reducing the adjustment time by more than 30%. At the same time, the threshold can be flexibly set according to process requirements, taking into account both speed and stability. This design also reduces the sensitivity to PID initial parameter tuning, improves the robustness and ease of use of the system, and is especially suitable for industrial environments with varying levels of operational expertise. It should be noted that the preset deviation threshold is preferably set to 0.05m to 0.1m, and this value is determined based on 10% to 20% of the preset value of the PE material's distance from the ground.

[0026] Furthermore, the detection process of the anomaly detection module includes: The human-machine interface displays the current ground clearance, traction speed, feeding motor speed and PID output value in real time. It also supports operators to modify the preset ground clearance and PID parameters online. When the laser rangefinder detects that the ground clearance exceeds the preset ground clearance for 5 seconds, it automatically stops the output of the traction frequency converter and issues an audible and visual alarm. Through the above technical solution, this embodiment provides the detection process of the anomaly detection module. The introduction of the human-machine interface transforms the system from a "black box" automatic control to a "visual and interactive" intelligent control system. The real-time display function allows operators and process engineers to intuitively observe the dynamic change trend of the ground clearance, the motor response, and whether the PID output is stable, facilitating timely detection of anomalies (such as sensor failure or mechanical jamming). More importantly, the ability to modify parameters online greatly improves the system's flexibility: without programming or shutdown, the preset ground clearance and PID gain can be adjusted according to the specifications of different PE hoses (such as wall thickness and material hardness) to achieve rapid production changeover. The anomaly detection and shutdown alarm functions are combined with delayed judgment, which not only avoids false alarms but also provides reliable safety protection when there is a real anomaly. The audible and visual alarms can promptly remind on-site personnel to handle the situation and prevent the fault from escalating.

[0027] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A traction motor control system for a PE hose production line, characterized in that, The system includes: The traction module includes an upper traction roller, a lower traction roller, and a traction inverter. The traction inverter is electrically connected to the upper traction roller and the lower traction roller and is used to traction the PE hose at a set constant speed. The feeding module comprises a feeding servo motor and a feeding roller, wherein the feeding servo motor and the feeding roller are electrically connected and used to release PE material. The control module, including a PID controller, is connected to the laser rangefinder and the feeding servo motor to adjust the speed of the feeding servo motor. The laser ranging module, including a laser ranging sensor, is installed between the traction module and the feeding module to measure the distance of the PE material from the ground in real time. The real-time adjustment module outputs a constant speed control signal to the traction module through the traction inverter to set a constant speed for traction of the PE hose. Based on the deviation between the real-time feedback ground distance and the preset ground distance, the speed of the feeding servo motor is adjusted in real time using a feedforward plus feedback composite control method, according to the PID controller. The anomaly detection module is used to automatically stop the output of the traction inverter and issue an audible and visual alarm when the laser rangefinder detects that the distance from the ground exceeds the preset distance by 5 seconds.

2. The traction motor control system for a PE hose production line according to claim 1, characterized in that, The traction inverter adopts a closed-loop speed control mode to ensure that the traction speed fluctuation does not exceed ±0.5%.

3. The traction motor control system for a PE hose production line according to claim 1, characterized in that, The adjustment process of the real-time adjustment module includes: Through formula Calculate the feedback control component of the PID controller at time t. ; Where t is the current time point, Let be the deviation of the ground distance at time t. As a dummy element in time integration, The cumulative integral is the deviation from the start time to time t. The first time derivative of the deviation. This is the proportional gain coefficient. This is the integral gain coefficient. This is the differential gain coefficient.

4. The traction motor control system for a PE hose production line according to claim 1, characterized in that, The adjustment process of the real-time adjustment module also includes: The feeding servo motor is equipped with an encoder feedback module, and the PID controller combines the encoder feedback signal and the laser ranging signal to achieve feedforward and feedback composite control, including: Through formula Calculate the feedforward control component of the PID controller at time t. ; Through formula The output PID controller calculates the command signal at time t and sends it to the unloading servo motor driver. ; in, This is the feedforward gain coefficient. This represents the traction speed output by the traction inverter at time t.

5. The traction motor control system for a PE hose production line according to claim 1, characterized in that, The adjustment process of the real-time adjustment module also includes: The PID controller combines the command signal calculated at time t and sent to the feeding servo motor driver. It outputs the corresponding current and voltage to drive the feeding servo motor to rotate at the target speed.

6. The traction motor control system for a PE hose production line according to claim 1, characterized in that, The adjustment process of the real-time adjustment module also includes: After the speed of the unloading servo motor is adjusted, the traction speed, ground clearance and unloading servo motor speed data are recorded at intervals of no less than 1 second, and exported to an external storage device via a network interface.

7. The traction motor control system for a PE hose production line according to claim 1, characterized in that, The PID controller includes an anti-integral saturation unit: when When this happens, the integral term stops accumulating and the integral state is reset according to the following formula: in, The preset deviation threshold value, This is the moment when the last deviation enters the threshold range.

8. The traction motor control system for a PE hose production line according to claim 1, characterized in that, The detection process of the anomaly detection module includes: The human-machine interface displays the current ground clearance, traction speed, feed motor speed and PID output value in real time. It also supports operators to modify the preset ground clearance and PID parameters online. When the laser rangefinder detects that the ground clearance exceeds the preset ground clearance for 5 seconds, it automatically stops the output of the traction frequency converter and issues an audible and visual alarm.

Images