Non-contact slip shaft tension control system and method based on magnetic circuit dynamic adjustment

Abstract

The invention discloses a non-contact slip shaft tension control system and method based on magnetic circuit dynamic adjustment. The system comprises a sensing network, an intelligent control unit and a dynamic adjustable permanent magnet eddy current coupler. The sensing network collects rotating speed, rolling diameter and tension data of the driving shaft and the load shaft in real time; the intelligent control unit dynamically updates the rotational inertia based on the real-time rolling diameter and performs feed-forward compensation calculation in combination with the angular acceleration to obtain a target total torque; meanwhile, a magnetic circuit parameter target value is solved by utilizing an inverse model of the eddy current torque physical model, and the magnetic circuit adjusting mechanism drives the magnet ring or the conductor ring to act, so that precise regulation and control of the torque are realized. In addition, the system estimates the torque in real time through a physical model and performs cross verification with the feedback value of the sensor, and has fault self-diagnosis and fault-tolerant switching capabilities. Mechanical abrasion and control lag of a traditional slip shaft are eliminated, the problems of tension fluctuation and inter-ring difference under the acceleration and deceleration working conditions are solved, and the reliability and control precision of a system are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the technical field of roll material processing equipment, specifically relating to a non-contact slip shaft tension control system and method based on dynamic adjustment of magnetic circuit. Background Technology

[0002] Maintaining constant material tension is crucial for ensuring product quality during the winding and unwinding of roll materials such as films, paper, and metal foils. The slip shaft, as the core component of tension control, achieves tension adjustment by generating a controllable slip torque between the drive shaft and the sliding sleeve (or slip ring) carrying the material.

[0003] Traditional differential shafts primarily rely on mechanical or pneumatic friction to generate torque. However, continuous wear of the friction pair leads to a gradual decrease and instability of tension, which is highly susceptible to temperature and humidity fluctuations, and the linearity and resolution of torque adjustment are limited. To overcome these shortcomings, permanent magnet eddy current differential shafts have emerged in the prior art. These shafts utilize the relative motion between a permanent magnet and a conductor ring to generate induced eddy currents, forming contactless torque coupling, eliminating mechanical wear, and improving equipment lifespan.

[0004] However, existing permanent magnet eddy current slip shafts still have the following significant technical problems in practical applications: 1. Insufficient control precision and sluggish response: Existing solutions are essentially "passive" torque coupling, with output torque primarily dependent on the preset magnetic circuit structure and naturally generated slip speed. Under dynamic conditions of rapid changes in roll diameter or altered material properties, the lack of active adjustment mechanisms prevents real-time sensing and precise torque adjustment, easily leading to compensation lag or ineffective compensation. This is the root cause of excessive differences between finished winding loops.

[0005] 2. Inability to effectively overcome inertial disturbances: Existing slip shaft control modes are mostly "passive response" rather than proactive and forward-looking adjustments based on operating conditions. During rapid acceleration and deceleration of the equipment, the huge rotational inertia of the winding package will generate severe inertial disturbances. Passive structures cannot effectively counteract these disturbances in real time, leading to drastic tension fluctuations and affecting the physical properties of the wound product.

[0006] 3. Low system integration and lack of intelligent closed loop: Existing technologies have not yet formed a complete "perception-decision-execution" intelligent closed loop control system, making it difficult to achieve adaptive control throughout the entire process.

[0007] 4. High Dependence on Key Sensors, Significant System Reliability Risks: Existing tension control systems heavily rely on a single tension sensor for feedback. In complex industrial production environments, sensors are highly susceptible to measurement distortion due to sensor failure, electromagnetic interference, or mechanical loosening. This single point of failure risk not only leads to fluctuations in product quality but may also trigger emergency equipment shutdowns, severely impacting the continuity and stability of the production line and failing to meet the stringent reliability requirements of intelligent manufacturing.

[0008] In summary, developing a highly reliable tension control system that can achieve high-precision dynamic active adjustment, effectively suppress inertial disturbances, and possess fault self-diagnosis and fault-tolerant operation capabilities is a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0009] To address the technical problems of insufficient control accuracy, hysteresis, poor inter-loop consistency, and low system reliability caused by excessive reliance on a single sensor in existing permanent magnet differential shafts that use passive compensation methods, this invention provides a contactless differential shaft tension control system and method based on dynamic adjustment of the magnetic circuit.

[0010] A non-contact slip shaft tension control system based on dynamic magnetic circuit adjustment, characterized in that it includes: A sensing network (100) is used to collect system operating status data in real time. The status data includes at least the drive shaft speed, load shaft speed, real-time outer diameter of the winding package, and real-time tension of the roll material. The intelligent control unit (200), connected to the sensing network (100), is used to receive the status data and execute the following control logic: Based on the real-time outer diameter and preset tension, feedforward compensation calculation is performed in conjunction with dynamically updated moment of inertia to obtain the target total torque; The target total torque is compared with the actual torque fed back, and the target value of the output magnetic circuit parameters is calculated by combining the inverse model of the eddy current torque physical model. A dynamically adjustable permanent magnet eddy current coupler (300) is signal-connected to the intelligent control unit (200) and includes a magnet ring and a conductor ring that can move relative to each other, as well as a magnetic circuit adjustment mechanism; the magnetic circuit adjustment mechanism is used to receive the target value of the magnetic circuit parameters and drive the magnet ring or conductor ring to move, so as to dynamically change the coupling state of the two and make the output torque track the target total torque.

[0011] Preferably, the sensing network (100) includes: The first speed sensor (101) is used to measure the speed of the active input shaft. ; The second speed sensor (102) is used to measure the speed of the conductor ring or load shaft. ; The roll diameter detection unit (103) is used for non-contact measurement of the real-time outer diameter of the winding package (400). ; A direct tension sensor (104) is used to measure the real-time tension value of the roll material. .

[0012] Preferably, the intelligent control unit (200) calculates the target total torque. The formula is: in, To set the tension, To adjust according to real-time roll diameter Dynamically updated moment of inertia of the winding package. ω represents the angular acceleration of the load axis.

[0013] Preferably, the physical model of the eddy current torque is: in, For the speed difference, This refers to the air gap between the magnet ring and the conductor ring. For effective magnetic flux density, The system constants; the target values ​​of the magnetic circuit parameters The target air gap is calculated based on the inverse model of the physical model. or target deflection angle .

[0014] Preferably, the magnetic circuit adjustment mechanism is a linear motor, a servo cylinder, or a piezoelectric ceramic actuator, used to drive the magnet ring to move axially to continuously adjust the air gap between it and the conductor ring. .

[0015] Preferably, the magnetic circuit adjustment mechanism is a rotary actuator used to drive the magnet ring or conductor ring to deflect by an angle, so as to change the effective cutting area between the magnetic pole and the conductor ring.

[0016] Preferably, the magnets on the magnet ring are arranged in a Hellbeck array.

[0017] Preferably, the intelligent control unit (200) further includes a sensorless torque estimation module, used to estimate the torque based on the real-time acquired air gap. Speed ​​difference Using the pre-stored model parameters, the eddy current torque physical model is used to calculate and output an estimated torque value in real time. .

[0018] Preferably, the intelligent control unit (200) is configured as follows: The estimated torque value Real-time cross-validation is performed with the actual torque feedback value obtained based on the direct tension sensor (104); When the deviation between the two exceeds a preset safety threshold, an alarm is triggered and the system's feedback source is switched to the estimated torque value. Implement closed-loop control.

[0019] This invention also discloses a non-contact slip shaft tension control method based on dynamic magnetic circuit adjustment, applicable to any of the systems described above, comprising the following steps: S1: Real-time data collection of drive shaft speed, load shaft speed, real-time outer diameter of the roll material, and real-time tension of the roll material via a sensing network; S2: Calculate the target torque, including inertia compensation, based on the set tension, real-time outer diameter, and dynamically updated moment of inertia. ; S3: Combining the current speed difference and the target torque The required target values ​​of magnetic circuit parameters are calculated using the inverse model of the eddy current torque physical model. ; S4: Drive the magnetic circuit adjustment mechanism to operate, so that the actual magnetic circuit parameters of the permanent magnet eddy current coupler reach... This enables output torque tracking ; S5: During system operation, the estimated torque value calculated by the physical model is redundantly checked against the directly measured tension feedback value, and the feedback source is switched when the sensor is abnormal.

[0020] Beneficial effects; (1) High-precision adaptive control: By establishing a physical model of eddy current torque and introducing feedforward compensation of rotational inertia, a millisecond-level response to tension fluctuations is achieved, eliminating tension peaks during acceleration and deceleration.

[0021] (2) Advantages of contactless transmission: The permanent magnet eddy current coupling structure is adopted, which fundamentally eliminates the wear, heat generation and maintenance costs caused by mechanical friction and extends the service life of the equipment. (3) High reliability and fault-tolerant operation: The innovative introduction of "sensorless torque estimation" as redundant feedback is used to verify with physical sensors in real time. In the event of sensor failure, seamless switching is achieved to ensure that the production line does not stop. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 Schematic diagram of the non-contact slip shaft tension control system based on dynamic adjustment of magnetic circuit.

[0024] Figure 2 : Control logic flowchart of the intelligent control unit. Detailed Implementation

[0025] 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.

[0026] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "center," "longitudinal," "lateral," "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] The following will refer to the appendices in the embodiments of the present invention. Figure 1 and appendix Figure 2 The technical solutions in the embodiments of the present invention will be clearly and completely described.

[0029] I. System Overall Architecture and Physical Connection Details; The contactless slip shaft tension control system based on dynamic magnetic circuit adjustment provided by this invention is designed to solve the problem of constant tension in high-precision winding equipment during rapid acceleration and deceleration.

[0030] 1. Mechanical actuation structure; The core actuator of the system is a dynamically adjustable permanent magnet eddy current coupler (300). The magnet ring (301) is fixed to the active input shaft of the system by a high-strength aluminum alloy bracket and rotates synchronously with the drive motor. High-performance neodymium iron boron permanent magnets are embedded in the magnet ring, and the magnets are arranged strictly according to the Hale-Becker array. The physical characteristic of this array is that it can generate an extremely strong sinusoidal magnetic field on the side close to the conductor ring through the magnetic field superposition effect, while the magnetic field on the opposite side is extremely weak, thereby greatly improving the efficiency and linearity of torque coupling without increasing the volume of the magnets.

[0031] The conductor ring (302) is located directly opposite the magnet ring, with an axial air gap maintained between them. The conductor ring is made of high-conductivity oxygen-free copper, and its thickness is preset according to the rated torque of the system design. The conductor ring is supported on the load shaft by a precision deep groove ball bearing, allowing it to rotate independently relative to the magnet ring, thus creating a speed difference. .

[0032] The magnetic circuit adjustment mechanism is key to achieving dynamic control. This embodiment employs a high-thrust servo electric cylinder, whose repeatability is superior to... The cylinder body of the electric cylinder is fixed to the end frame of the differential shaft, and the push rod is connected to the magnet ring via a rotary joint. When the intelligent control unit issues an air gap adjustment command, the servo electric cylinder drives the magnet ring to translate axially, thereby changing the air gap. By utilizing the physical law that eddy current torque is inversely proportional to the square of the air gap distance, continuous, stepless, and high-resolution adjustment of the output torque can be achieved.

[0033] 2. Sensing network layout; The sensing network (100) forms the basis for the system's real-time feedback: Input-side monitoring: The first speed sensor (101) is installed at the non-output end of the motor, using... Linear incremental encoder, sampling frequency not less than 1000 Hz To ensure continuous and accurate acquisition of spindle angular velocity .

[0034] Output-side monitoring: The second speed sensor (102) is located on the driven side of the slip shaft and is used to monitor the rotational angular velocity of the winding package in real time. .

[0035] Physical tension measurement: The direct tension sensor (104) uses a high-precision strain gauge pressure transmitter, integrated below the bearing housing of the last guide roller before winding, and outputs... Analog signals reflect the actual tension of the roll material. .

[0036] Real-time roll diameter detection: The roll diameter detection unit (103) uses a laser sensor mounted on the top of the frame to calculate the current winding radius in real time by measuring the change in distance from the sensor to the surface of the roll. .

[0037] II. Algorithm Implementation Details of the Intelligent Control Unit; The control program running inside the intelligent control unit (200) is not just a simple PID adjustment, but a composite algorithm that combines feedforward and feedback from the physical model.

[0038] 1. Adaptive calculation of rotational inertia; During the winding process, the mass and volume of the winding package (400) increase rapidly over time, resulting in its moment of inertia. It is a nonlinear, time-varying parameter. The control unit updates it dynamically through the following subroutine: in, The moment of inertia of the empty axis. For roll density, For the width of the roll, This is the radius of the winding shaft core. Whenever the roll diameter... occur When the above changes occur, the system will recalculate. This value provides a precise benchmark for feedforward compensation.

[0039] 2. Feedforward decision-making for target total torque To address speed fluctuations during system startup, shutdown, and roll changing, the control unit executes the following formula: Here, This is the target tension preset by the user in the HMI interface. The system uses feedback from the second speed sensor... Perform real-time first-order difference to calculate the current load angular acceleration. When the system is in a constant-speed operation phase, Torque is primarily used to overcome tension; when the system is in a phase of rapid acceleration, The feedforward term actively increases the torque output to counteract the inertial torque required for acceleration and prevent the roll material from loosening due to lag.

[0040] 3. Physical model of eddy current torque and inverse calculation of air gap To convert torque demand into displacement of the electric cylinder, the control unit incorporates a physical model of eddy current torque based on polynomial correction: in, The magnetic field strength, It is a comprehensive coefficient that includes physical constants such as conductor conductivity, number of pole pairs, and effective radius. When calculated... Then, the algorithm solves for the target air gap in real time using an inverse model. III. Deep implementation of redundancy verification and fault tolerance mechanisms; This is the core characteristic of the system's high reliability. The system employs a dual-channel torque monitoring mode.

[0041] 1. Monitoring phase; During stable system operation, the control unit continuously runs the "sensorless torque estimation module." This module does not rely on signals from the tension sensor, but rather on the actual air gap position currently fed back by the servo cylinder. and speed difference Substituting the values ​​into the above physical model, the estimated torque is calculated. .

[0042] 2. Cross-validation logic; The control unit compares the readings in real time with those calculated by the direct tension sensor. and deviation value : Normal operating state: If At the rated value Within, the system is This serves as the main feedback for closed-loop correction. For supplementary reference. Abnormal diagnostic state: If the tension sensor becomes loose due to field vibration, or if the signal is abnormal due to line interference, It will rapidly expand and exceed the preset safety threshold (such as...) ).

[0043] 3. Fault-tolerant and seamless handover; If the deviation exceeds the limit, the control unit immediately executes the following fault-tolerant strategies: Alarm triggering: A "Sensor data suspicious" warning pops up on the HMI interface, prompting maintenance personnel to check the hardware. Algorithm takeover: The control system... The closed-loop feedback link of the tension meter is automatically disconnected within milliseconds, seamlessly switching the control feedback source to... Maintaining production: due to Based on charge induction and physical laws, its accuracy is slightly lower than that of precision sensors, but it is sufficient to ensure that there is no material breakage or wrinkling during the production process, and to keep the equipment running until the finished roll is rewound.

[0044] IV. Implementation examples of operation procedures for specific working conditions; The following describes the system's performance during a complete roll-up process from "empty roll" to "full roll".

[0045] 1. Start-up phase; Initially, the roll diameter Minimum spindle speed. The load increases linearly from zero. At this point, the control unit detects through the sensing network that the load is stationary, and the system performs startup inertia compensation. The servo electric cylinder quickly pushes the magnet ring to the minimum air gap position (e.g., It outputs a large starting torque to overcome the static friction of the system.

[0046] 2. Constant speed winding stage; As winding proceeds, the roll diameter... The distance gradually increases. The laser sensor reports data showing a decrease in distance in real time, and the control unit increases accordingly. The input value. To maintain line tension. Constant, required torque Must follow Linear increase. The control unit directs the servo cylinder to move axially in extremely small steps (micrometer level), smoothly reducing the air gap. This allows the coupling torque to accurately track the change curve of the roll diameter.

[0047] 3. Dynamic fluctuation handling; If a sudden change in the tension of the roll material causes a jump in the tension due to a sudden change in the preceding traction speed, the direct tension sensor will detect... Deviation. The PID controller within the system adds this deviation to the feedforward instruction to calculate the corrected value. The electric cylinder is Response is completed within milliseconds, eliminating fluctuations.

[0048] 4. Full roll deceleration stage; When the roll diameter is detected to be close to the set full roll radius, the motor begins to decelerate. At this time, the angular acceleration... The feedforward compensation module calculates the excess torque demand caused by the large inertia, and the control unit actively instructs the electric cylinder to instantaneously increase the air gap of the magnetic circuit. This weakens the eddy current coupling strength, thereby preventing excessive tension from breaking the material during deceleration.

[0049] V. Implementation Instructions for Structural Variations; In another embodiment of the present invention, the magnetic circuit adjustment mechanism can be replaced by a rotary servo motor. The magnet ring is divided into inner and outer layers, and one layer is driven by the rotary servo motor to rotate relative to the other layer by a certain angle. This method, by changing the effective alignment and overlap area of ​​the magnet array (i.e., changing the flux density of the synthetic magnetic field), can also achieve precise control of the coupling torque, and is suitable for compact machine tool installation environments with extremely limited axial space.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations 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 scope of the present invention.

Claims

1. A non-contact slip shaft tension control system based on dynamic magnetic circuit adjustment, characterized in that, include: A sensing network (100) is used to collect system operating status data in real time. The status data includes at least the drive shaft speed, load shaft speed, real-time outer diameter of the winding package, and real-time tension of the roll material. The intelligent control unit (200), connected to the sensing network (100), is used to receive the status data and execute the following control logic: Based on the real-time outer diameter and preset tension, feedforward compensation calculation is performed in conjunction with dynamically updated moment of inertia to obtain the target total torque; The target total torque is compared with the actual torque fed back, and the target value of the output magnetic circuit parameters is calculated by combining the inverse model of the eddy current torque physical model. A dynamically adjustable permanent magnet eddy current coupler (300) is signal-connected to the intelligent control unit (200) and includes a magnet ring and a conductor ring that can move relative to each other, as well as a magnetic circuit adjustment mechanism; the magnetic circuit adjustment mechanism is used to receive the target value of the magnetic circuit parameters and drive the magnet ring or conductor ring to move, so as to dynamically change the coupling state of the two and make the output torque track the target total torque.

2. The system according to claim 1, characterized in that, The sensing network (100) includes: The first speed sensor (101) is used to measure the speed of the active input shaft. ; The second speed sensor (102) is used to measure the speed of the conductor ring or load shaft. ; The roll diameter detection unit (103) is used for non-contact measurement of the real-time outer diameter of the winding package (400). ; A direct tension sensor (104) is used to measure the real-time tension value of the roll material. .

3. The system according to claim 2, characterized in that, The intelligent control unit (200) calculates the target total torque. The formula is: in, To set the tension, To adjust according to real-time roll diameter Dynamically updated moment of inertia of the winding package. ω represents the angular acceleration of the load axis.

4. The system according to claim 3, characterized in that, The physical model for the eddy current torque is as follows: in, For the speed difference, This refers to the air gap between the magnet ring and the conductor ring. For effective magnetic flux density, The system constants; the target values ​​of the magnetic circuit parameters The target air gap is calculated based on the inverse model of the physical model. or target deflection angle .

5. The system according to claim 1, characterized in that, The magnetic circuit adjustment mechanism is a linear motor, a servo cylinder, or a piezoelectric ceramic actuator, used to drive the magnet ring to move axially to continuously adjust the air gap between it and the conductor ring. .

6. The system according to claim 1, characterized in that, The magnetic circuit adjustment mechanism is a rotary actuator used to drive the magnet ring or conductor ring to deflect by an angle, thereby changing the effective cutting area between the magnetic pole and the conductor ring.

7. The system according to claim 1, characterized in that, The magnets on the magnet ring are arranged in a Hellbeck array.

8. The system according to any one of claims 1 to 4, characterized in that, The intelligent control unit (200) also includes a sensorless torque estimation module, used to estimate the torque based on the real-time air gap data. Speed ​​difference Using the pre-stored model parameters, the eddy current torque physical model is used to calculate and output an estimated torque value in real time. .

9. The system according to claim 8, characterized in that, The intelligent control unit (200) is configured to: The estimated torque value Real-time cross-validation is performed with the actual torque feedback value obtained based on the direct tension sensor (104); When the deviation between the two exceeds a preset safety threshold, an alarm is triggered and the system's feedback source is switched to the estimated torque value. Implement closed-loop control.

10. A non-contact slip shaft tension control method based on dynamic magnetic circuit adjustment, applied to the system as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: Real-time data collection of drive shaft speed, load shaft speed, real-time outer diameter of the roll material, and real-time tension of the roll material via a sensing network; S2: Calculate the target torque, including inertia compensation, based on the set tension, real-time outer diameter, and dynamically updated moment of inertia. ; S3: Combining the current speed difference and the target torque The required target values ​​of magnetic circuit parameters are calculated using the inverse model of the eddy current torque physical model. ; S4: Drive the magnetic circuit adjustment mechanism to operate, so that the actual magnetic circuit parameters of the permanent magnet eddy current coupler reach... This enables output torque tracking ; S5: During system operation, the estimated torque value calculated by the physical model is redundantly checked against the directly measured tension feedback value, and the feedback source is switched when the sensor is abnormal.

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