Flexible functional fiber constant stress winding forming method and winding equipment
By introducing constant total stress control and integral sliding mode algorithm, the tension and back pressure during the yarn winding process are adjusted in a coordinated manner, which solves the problem of uneven stress distribution inside the yarn package and improves the stability and uniformity of yarn winding.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG SCI-TECH UNIV
- Filing Date
- 2026-04-14
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies fail to effectively coordinate and control winding tension, back pressure, and winding angle during yarn winding, resulting in non-uniform stress distribution inside the yarn package, leading to structural instability, yarn loosening, or breakage.
A constant total stress control method is introduced. By constructing the relationship between total stress and yarn target tension, and combining it with integral sliding mode control algorithm, the overfeed motor and the back pressure of the rotating arm are adjusted in a coordinated manner to ensure that the total stress is constant during the winding process and optimize the dynamic adjustment of yarn pretension and back pressure.
It effectively eliminates the "tight inside and loose outside" defect in the yarn package, enhances the structural stability of the yarn package forming process, avoids yarn loosening and breakage, and improves the uniformity and quality of yarn winding.
Smart Images
Figure CN122013384A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of yarn doubling process, specifically relating to a method and equipment for constant stress winding of flexible functional fibers. Background Technology
[0002] Yarn doubling, a key process in the textile industry for improving yarn strength and uniformity, primarily relies on doubling machines to combine multiple single yarns. Its forming quality depends on the precise control of process parameters such as tension, winding angle, and back pressure. Currently, the most similar implementations to this invention mainly include strategies such as constant tension winding, constant torque winding, tapered tension winding, and constant stress control. While constant stress control attempts to optimize forming by eliminating the difference between the actual stress within the winding layer and the set pretension, and existing technologies widely employ algorithms such as PID, internal mold control, or active disturbance rejection control to finely adjust yarn tension, these solutions typically focus only on single-variable control of yarn tension, neglecting the dynamic adjustment of friction roller back pressure and its crucial impact on winding density. Because winding tension, back pressure, and winding angle are not considered in a coordinated manner, these traditional solutions still lead to a non-uniform stress distribution within the yarn package—"tight inside, loose outside"—when facing changes in winding radius, resulting in insufficient structural stability or yarn slippage.
[0003] The main drawback of existing technologies (mainly constant tension control strategies) is that they only focus on the constant external winding tension, while ignoring the cumulative effect of internal stress during the yarn forming process. This leads to the outer yarn squeezing the inner layer as the number of winding layers increases, resulting in a non-uniform density distribution of the yarn in the form of "tight inside and loose outside", which in turn causes quality defects such as structural instability, loose yarn, or even breakage. Summary of the Invention
[0004] The purpose of this invention is to provide a method and equipment for constant stress winding of flexible functional fibers.
[0005] In a first aspect, the present invention provides a method for constant stress winding and molding of flexible functional fibers, characterized in that: the method includes:
[0006] Set yarn material parameters and process parameters; the process parameters include target total stress, target back pressure, and target package radius.
[0007] Based on the current winding layer stress, the additional stress of all outer layers of the current winding layer on the current winding layer is introduced to construct the total stress of the current winding layer, thereby constructing the relationship between the total stress and the yarn target tension. Under the condition of constant total stress, the yarn target tension is obtained; under the condition of constant back pressure, the yarn pretension is obtained according to the yarn target tension and back pressure.
[0008] Adjust the winding speed, overfeed motor linear speed, and arm pressure of the current winding layer according to the yarn pretension of the current winding layer;
[0009] Repeat the above process until the current winding radius of the winding layer reaches the target winding radius.
[0010] Preferably, the total stress includes total radial stress and total tangential stress; the total radial stress is the sum of the initial radial stress of the current winding layer and the radial stress of all outer winding layers of the corresponding winding layer; the total tangential stress is the sum of the initial tangential stress of the current winding layer and the tangential stress of all outer winding layers of the corresponding winding layer.
[0011] Preferably, the initial radial stress is obtained based on the back pressure of the current winding layer and the thickness of a single layer of yarn; the initial tangential stress is obtained based on the winding tangential tension of the current winding layer and the thickness of a single layer of yarn.
[0012] Preferably, the winding tangential tension is the product of the cosine of the winding angle and the target tension of the yarn.
[0013] Preferably, the arm pressure is adjusted by adding the feedforward equivalent control and the nonlinear switching control to obtain the back pressure of the current winding layer; and by performing an inverse solution based on the original force formula of the back pressure to obtain the arm pressure to be adjusted.
[0014] Preferably, the feedforward equivalent control is obtained based on the yarn pretension and the yarn target tension; the nonlinear switching control is obtained based on the difference between the yarn measured tension and the yarn target tension.
[0015] Preferably, the method for obtaining the target yarn tension is as follows:
[0016] The generalized radial stiffness is obtained based on the material parameters of the bobbin; the relationship between the winding layer stress and the target yarn tension is constructed based on the generalized radial stiffness and the winding layer radius, and the relationship between the winding layer stress and the total stress is combined to obtain the relationship between the total stress and the target yarn tension; the target yarn tension is obtained under the condition of constant total stress.
[0017] Preferably, the material parameters include the inner radius of the tube, the outer radius of the tube, the weight of the tube, the relevant elastic modulus, and Poisson's ratio.
[0018] Preferably, the radial elastic modulus of the tube is equal to the tangential elastic modulus of the tube; the radial Poisson's ratio of the tube is equal to the tangential Poisson's ratio of the tube.
[0019] Secondly, the present invention provides a flexible functional fiber constant stress winding device for performing the above-described winding and forming method; the winding device includes a rotating arm and a magnetic ring, a yarn guide, a friction roller, a bobbin, and a drive module mounted on the rotating arm; the magnetic ring is used to twist multiple yarns and then convey them to the yarn guide; the yarn guide is used to adjust the angle at which the yarn is wound on the bobbin; the friction roller is used to complete the winding of the yarn on the bobbin;
[0020] The drive module includes an overfeed motor, a traverse motor, a rotating arm motor, and a winding motor; the overfeed motor is used to adjust the speed of the yarn fed to the yarn guide by the magnetic ring; the traverse motor is used to adjust the horizontal position of the yarn guide; the rotating arm motor is used to control the torque on the rotating arm; and the winding motor is used to control the winding speed of the bobbin.
[0021] The beneficial effects of this invention are:
[0022] 1. This invention introduces a constant total stress to solve for the yarn pretension during the yarn winding control process. The total stress is the total stress of a certain layer of the bobbin after winding, which is the result of the combined effect of the current winding layer stress and the stress of each external winding layer. By introducing the total stress, the influence of the external layer stress on the winding layer stress can be added, thereby successfully decoupling the tangential and radial stresses of the winding layer. Based on this, the evolution law of the pretension required to maintain a constant internal total stress can be solved, thus eliminating the "tight inside and loose outside" defect caused by the material being squeezed from the theoretical root.
[0023] 2. This invention transforms the control domain to the winding radius domain and utilizes an integral sliding mode control algorithm to enable the system to possess extremely strong global robustness to mechanical vibration and sudden changes in friction coefficient, effectively overcoming the steady-state error and hysteresis phenomenon of traditional algorithms in variable diameter winding. Based on this, this invention constructs a collaborative control mechanism of feedforward pretension from the overfeed motor and dynamic adjustment of back pressure by the rotating arm, ensuring the optimal ratio of the tangential component of the yarn package to the radial pressure, greatly enhancing the overall structural stability during the yarn package forming process. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the overall structure in Embodiment 1 of the present invention.
[0025] Figure 2 This is a schematic diagram of the force analysis of the yarn on the winding device in Embodiment 2 of the present invention.
[0026] Figure 3 This is a schematic diagram of the stress situation at the cross-section of the winding layer in Embodiment 2 of the present invention.
[0027] Figure 4 This is a schematic diagram of the mechanical model of the yarn winding bobbin in Embodiment 2 of the present invention.
[0028] Reference numerals: 1. Rotating arm; 2. Magnetic ring; 3. Overfeed motor; 4. Tension sensor; 5. Traverse motor; 6. Yarn guide; 7. Friction roller; 8. Boll tube. Detailed Implementation
[0029] The present invention will be further described below with reference to the accompanying drawings.
[0030] Example 1
[0031] like Figure 1 As shown, a flexible functional fiber constant stress winding device includes a rotating arm 1 and a magnetic ring 2, a yarn guide 6, a friction roller 7, a bobbin 8, and a drive module mounted on the rotating arm 1. The magnetic ring 2 is used to twist multiple raw material yarns and then feed them to the yarn guide 6. A tension sensor 4 is installed between the magnetic ring 2 and the yarn guide 6 to detect yarn tension. The yarn guide 6 is used to adjust the angle at which the yarn is wound on the bobbin 8, completing precise cross-winding of the bobbin 8. The edge of the friction roller 7 is in contact with the yarn wound on the bobbin 8 to complete the yarn winding.
[0032] The drive module includes an overfeed motor 3, a traverse motor 5, a rotating arm motor, and a winding motor. The overfeed motor 3 regulates the speed of the yarn fed from the magnetic ring 2 to the yarn guide 6. The traverse motor 5 regulates the horizontal position of the yarn guide 6. The rotating arm motor, mounted inside the rotating arm 1, controls the torque on the rotating arm 1. As the yarn winds, the torque on the rotating arm motor changes to keep the tangential component of the friction roller 7 relative to the bobbin 8 constant. The winding motor controls the winding speed of the bobbin 8, and the yarn tension is controlled by the speed difference between the winding motor and the overfeed motor 3.
[0033] Example 2
[0034] A method for constant stress winding and molding of flexible functional fibers, used to control the winding equipment in Example 1; the winding and molding method includes the following steps:
[0035] Step 1: Set yarn material parameters and process parameters
[0036] Material parameters include the inner radius *a* of the bobbin, the outer radius *b* of the bobbin, the weight of the bobbin, relevant elastic modulus, and Poisson's ratio. Process parameters include the target roll radius *R* and the target back pressure. And the target total stress.
[0037] Step Two, as follows Figure 2 , 3 As shown in Figure 4, under the conditions of constant stress and constant back pressure, a nonlinear functional relationship between yarn pretension and winding radius is constructed, and the yarn pretension under different winding radii is obtained. The specific process is as follows:
[0038] 2-1. Construct a functional relationship between total stress and target yarn tension.
[0039] If the material of the bobbin is isotropic, then the following relationship exists:
[0040] (1)
[0041] in, The radial elastic modulus of the tube; The tangential elastic modulus of the tube; The elastic modulus of the tube; The radial Poisson's ratio of the cylinder; The tangential Poisson's ratio of the cylinder; is the Poisson's ratio for the cylinder.
[0042] Based on the elastic modulus of the tube Poisson's ratio of the tube Constructing generalized radial stiffness It is represented as:
[0043] (2)
[0044] Where a is the inner radius of the tube; b is the outer radius of the tube.
[0045] Based on the coil radius, the elastic modulus of the bobbin, and the Poisson's ratio of the coiled layer, the stress and displacement of the coiled layer under plane stress conditions are expressed as follows:
[0046] (3)
[0047] (4)
[0048] in, and These are the radial stress and tangential stress of the winding layer, respectively; and These are the general solution coefficients; The winding radius is the sum of the outer radius of the tube and the thickness of the winding layer. This represents the radial displacement of the winding layer; The radial elastic modulus of the winding layer; The tangential elastic modulus of the winding layer; The Poisson's ratio of the wound layer.
[0049] The inner and outer boundary conditions of the yarn winding layer are set as follows:
[0050] (5)
[0051] in, This indicates the radial stress of the wound layer when the winding radius is the outer radius of the tube. This indicates the radial displacement of the wound layer when the winding radius is the outer radius of the tube. For the winding radius is Radial stress of the winding layer; The radial outward compressive stress generated by the yarn winding tension. ; The target tension of the yarn.
[0052] Substituting formulas (3) and (4) into formula (5), the general solution coefficients are obtained as follows:
[0053] (6)
[0054] in, As an intermediate variable, it is represented as:
[0055] (7)
[0056] in, The tangential elastic modulus of the winding layer; The radial elastic modulus of the winding layer; The Poisson's ratio of the wound layer.
[0057] Substituting formula (6) into formula (3), the expression for the stress of the winding layer affected by the winding tension during the winding process is obtained as follows:
[0058] (8)
[0059] (9)
[0060] Will Replace with , Replace with The radial stress of the wound layer under winding tension under plane strain conditions can be obtained. and tangential stress of the winding layer The expression is as follows:
[0061] (10)
[0062] (11)
[0063] in, As an intermediate variable, it is represented as:
[0064] (12)
[0065] The expression for the winding layer stress with respect to winding preload and back pressure is derived using the elastic superposition method. During yarn winding, the yarn is guided by a yarn guide and precisely cross-wound onto the bobbin. When the yarn reaches a specific point on the bobbin surface, its tangential direction generates an angle relative to the circumferential velocity direction during precise cross-winding; this angle is defined as the winding angle. And according to the winding angle The winding tangential tension when the yarn is wound into the i-th layer Represented as:
[0066] (13)
[0067] in, The winding angle; This refers to the length of the bobbin winding; The winding ratio is constant.
[0068] Maintaining constant winding layer stress ignores the cumulative effect of internal stress during the yarn package formation process. As the number of winding layers increases, the outer yarn continuously exerts radial pressure on the inner yarn. This pressure causes deformation and loosening of the inner yarn, significantly weakening the tangential tensile stress originally generated during winding. Ultimately, this results in a non-uniform density distribution of the yarn package, characterized by "tight inside and loose outside," and this non-uniform stress distribution easily leads to forming defects such as insufficient structural stability, yarn loop slippage, and even yarn breakage. This invention introduces total stress and controls the yarn package formation process by keeping the total stress constant. The yarn package formation process is viewed as a series of rings (elastic cylindrical shells). Each layer of yarn exerts radial pressure on the inner winding layer during winding. Based on the sum of the initial stress and the additional stress generated by the superposition of all subsequent outer layers, the yarn is wound to the nth layer, i.e., to the target package radius (…). When ), the total tangential stress acting on the i-th layer of yarn Its expression is:
[0069] (14)
[0070] in, Indicates the thickness of a single layer of yarn; is the winding radius when the yarn is wound to the i-th layer.
[0071] Obtain the remaining tangential force of the yarn winding layer The expression is:
[0072] (15)
[0073] Combining formulas (14) and (15), the total tangential stress acting on the i-th layer when the yarn is wound to the n-th layer is obtained. and total radial stress Its expression is:
[0074] (16)
[0075] (17)
[0076] in, This is back pressure.
[0077] Based on formulas (16) and (17), the relationship between the target yarn tension and the yarn winding radius is constructed as follows:
[0078] (18)
[0079] 2-2. Obtaining yarn pretension based on back pressure and target tension
[0080] Based on the theory of elastic stress and the principle of elastic superposition, a mechanical model is established that includes the yarn winding radius, winding angle, yarn physical properties, yarn tension, and friction roller back pressure. During the winding process, the winding tension is affected by the gravity of the yarn package. and arm pressure Therefore, the sum of the weight of the yarn package and the force exerted by the rotating arm on the friction roller is divided into a pressure tangential component along the yarn. and the radial component of the pressure of the yarn It is represented as follows:
[0081] (19)
[0082] in, The back pressure angle represents the angle between the back pressure direction and the horizontal direction of the yarn bundle. This represents the force exerted by the rotating arm on the friction roller.
[0083] back pressure The back pressure is the reaction force exerted by the friction roller on the yarn package, which is perpendicular to the tangential direction at the contact point between the yarn package and the friction roller; simultaneously, the back pressure is the reaction force of the arm pressure component along the radial direction and gravity; the back pressure when the yarn package is wound to the i-th layer. Rolling friction, or yarn friction, exists at the contact point between the friction roller and the yarn package. Where u is the coefficient of friction.
[0084] The yarn is subjected to yarn pretension applied by a tension controller during the winding process. It is tangentially wound onto the surface of the yarn tube at the contact point between the friction roller and the yarn tube. The direction of yarn entry and the applied pretension of the yarn package... The directions are all consistent with the tangential direction of the friction roller. Yarn target tension equal to back pressure in the tangential direction Add yarn pretension Subtract friction It is represented as:
[0085] (20)
[0086] Substituting formula (18) into formula (20), the yarn pretension applied by the tension controller is obtained. .
[0087] Step 3: Obtain the theoretical speed of different motors
[0088] Based on the fundamental principle of Hooke's Law, the stress-strain response satisfies the linear elastic characteristic, that is:
[0089] (twenty one)
[0090] Where A represents the cross-sectional area of the yarn under stress; E represents the elastic modulus of the yarn; This represents the elastic elongation of the yarn under tension; S is the original length of the yarn when it is not under tension.
[0091] The length S of the yarn when it is not stretched under tension is expressed as:
[0092] (twenty two)
[0093] in, The yarn length between the overfeed motor and the yarn tension sensor; The vertical distance between the yarn tension sensor and the yarn guide; This is the vertical distance between the yarn guide and the take-up point on the bobbin. This indicates the winding angle during the current yarn winding process; This indicates the direction of yarn movement between the sensor and the friction roller, and the linear velocity of the overfeed motor. The angle between them.
[0094] Elastic elongation Winding speed With the linear velocity of the overfeed motor In unit time Integral of the interpolation values.
[0095] (twenty three)
[0096] Substitute formulas (22) and (23) into formula (21) to obtain the yarn pretension and winding speed. and the linear velocity of the overfeed motor The relationship is as follows:
[0097] (twenty four)
[0098] Due to winding speed The speed of the transverse motor and winding motor speed Control, overfeed motor linear speed The speed of the overfeed motor Control; build winding speed and the linear velocity of the overfeed motor The relationship with different motor speeds is as follows:
[0099] (25)
[0100] in, The radius of the winding roller corresponding to the traverse motor; The radius of the guide roller corresponding to the winding motor; This is the radius of the overfeed roller corresponding to the overfeed motor.
[0101] Substituting formula (25) into formula (24), the relationship between different motor speeds and yarn pretension is expressed as follows:
[0102] (26)
[0103] Based on the yarn pretension obtained in step two Speed commands are directly issued to the traverse motor, winding motor, and overfeed motor. At this time, the overfeed motor only acts as the actuator for the reference tension, continuously providing the basic pretension along the preset trajectory.
[0104] Step 4: Back pressure dynamic coordinated control based on target tension feedback
[0105] A yarn tension sensor installed between the overfeed motor and the yarn guide is used to collect the current winding radius in real time and at high frequency. Tension measurement Measure the tension of the yarn. With the calculated target yarn tension Perform real-time comparison to obtain the yarn winding to the first... Tension deviation during layering Its expression is:
[0106] (27)
[0107] To eliminate steady-state errors in the control process and to become "immune" to sudden changes in mechanical vibration and friction, the winding radius... Constructing an integral sliding surface within the domain It is represented as follows:
[0108] (28)
[0109] in, The sliding surface parameters, which are greater than zero, determine the convergence rate of the error in the winding space.
[0110] To ensure that the system state is always constrained on the sliding surface (i.e., approaches the state of the sliding surface) ), calculate the back pressure that needs to be compensated at the current instant. The control law consists of two parts: feedforward equivalent control. and nonlinear switching control Based on the decoupling model, the feedforward equivalent control is calculated as follows:
[0111] (29)
[0112] in, is the coefficient of friction.
[0113] To overcome unmodeled disturbances, an exponential reaching law is introduced, and the nonlinear switching control is calculated as follows:
[0114] (30)
[0115] in, and These are the linear gain and robust switching gain of the sliding mode controller, respectively. It is a symbolic function.
[0116] The system's final output real-time target backpressure command is:
[0117] (31)
[0118] The relationship between back pressure and arm pressure is expressed as follows:
[0119] (32)
[0120] in, The weight of the yarn package when it is wound to the i-th layer; This indicates the arm pressure when the yarn is wound to the i-th layer; This represents the total length of the yarn on the cylinder when the yarn is wound to the i-th layer; The linear density of the yarn; This refers to the weight of the yarn bobbin.
[0121] Total length It is obtained iteratively from the winding length of each layer, and its expression is:
[0122] (33)
[0123] in, This is the winding length.
[0124] Calculate the real-time back pressure required to maintain constant tension. Then, the inverse equation of the original force formula for back pressure is used to obtain the required arm pressure. :
[0125] (34)
[0126] The physical motion of the rotary arm motor is obtained based on the required arm pressure.
[0127] Step 5: Repeat steps 2 to 4 at a high-frequency sampling rate until the winding radius reaches the set target winding radius R, thus completing the winding process of the multi-yarn.
Claims
1. A method for constant stress winding and molding of flexible functional fibers, characterized in that: The method includes: Set yarn material parameters and process parameters; the process parameters include target total stress, target back pressure, and target package radius. Based on the current winding layer stress, the additional stress of all outer layers of the current winding layer is introduced to construct the total stress of the current winding layer, and the yarn target tension is obtained under the condition of constant total stress; under the condition of constant back pressure, the yarn pretension is obtained according to the yarn target tension and back pressure. Adjust the winding speed, overfeed motor linear speed, and arm pressure of the current winding layer according to the yarn pretension of the current winding layer; Repeat the above process until the current winding radius of the winding layer reaches the target winding radius.
2. The method for constant stress winding and molding of flexible functional fibers according to claim 1, characterized in that: The total stress includes total radial stress and total tangential stress; the total radial stress is the sum of the initial radial stress of the current winding layer and the radial stress of all outer winding layers of the corresponding winding layer; The total tangential stress is the sum of the initial tangential stress of the current winding layer and the tangential stress of all the outer winding layers of the corresponding winding layer.
3. The method for constant stress winding and molding of flexible functional fibers according to claim 2, characterized in that: The initial radial stress is obtained based on the back pressure of the current winding layer and the thickness of a single layer of yarn; the initial tangential stress is obtained based on the winding tangential tension of the current winding layer and the thickness of a single layer of yarn.
4. The method for constant stress winding and molding of flexible functional fibers according to claim 3, characterized in that: The winding tangential tension is the product of the cosine of the winding angle and the target tension of the yarn.
5. The method for constant stress winding and molding of flexible functional fibers according to claim 1, characterized in that: The arm pressure adjustment is based on the following: adding the feedforward equivalent control and the nonlinear switching control to obtain the back pressure of the current winding layer; and performing an inverse solution based on the original force formula of the back pressure to obtain the arm pressure to be adjusted.
6. The method for constant stress winding and molding of flexible functional fibers according to claim 5, characterized in that: The feedforward equivalent control is obtained based on the yarn pretension and the target yarn tension; the nonlinear switching control is obtained based on the difference between the measured yarn tension and the target yarn tension.
7. The method for constant stress winding and molding of flexible functional fibers according to claim 1, characterized in that: The method for obtaining the target tension of the yarn is as follows: The generalized radial stiffness is obtained based on the material parameters of the bobbin; the relationship between the winding layer stress and the target yarn tension is constructed based on the generalized radial stiffness and the winding layer radius, and the relationship between the total stress and the target yarn tension is obtained by combining the relationship between the winding layer stress and the total stress. The target tension of the yarn is obtained under constant total stress.
8. The method for constant stress winding and molding of flexible functional fibers according to claim 1, characterized in that: The material parameters include the inner radius of the tube, the outer radius of the tube, the weight of the tube, the relevant elastic modulus, and Poisson's ratio.
9. The method for constant stress winding and molding of flexible functional fibers according to claim 8, characterized in that: The radial elastic modulus of the tube is equal to the tangential elastic modulus of the tube; the radial Poisson's ratio of the tube is equal to the tangential Poisson's ratio of the tube.
10. A flexible functional fiber constant stress winding device, characterized in that: The device is used to perform a constant stress winding molding method for flexible functional fibers as described in claim 1. The winding device includes a rotating arm (1) and a magnetic ring (2), a yarn guide (6), a friction roller (7), a bobbin (8), and a drive module mounted on the rotating arm (1). The magnetic ring (2) is used to twist multiple yarns and then feed them to the yarn guide (6). The yarn guide (6) is used to adjust the angle at which the yarn is wound on the bobbin (8). The friction roller (7) is used to complete the winding of the yarn on the bobbin (8). The drive module includes an overfeed motor (3), a traverse motor (5), a rotating arm motor, and a winding motor; the overfeed motor (3) is used to adjust the speed of the yarn fed from the magnetic ring (2) to the yarn guide (6); the traverse motor (5) is used to adjust the horizontal position of the yarn guide (6); the rotating arm motor is used to control the torque on the rotating arm (1); and the winding motor is used to control the winding speed of the bobbin (8).