A low tension weft laying control method and system

Abstract

The present application relates to the technical field of warp knitting, and particularly relates to a low-tension weft laying control method and system, which comprises the following steps: obtaining a current weft laying angle, a weft laying width, a chain running speed, a current position of a weft laying trolley and a current position of a slide table; calculating a current wrapping angle of a yarn on a slide table needle; calculating a moving distance a of the weft laying trolley and a moving distance b of the slide table required to reach a target wrapping angle; controlling the weft laying trolley to move in a reverse direction of chain movement by the distance a, while controlling the slide table to move in a chain movement direction by the distance b; controlling the weft laying trolley and the slide table to keep a relative position distance interval of a+b and move synchronously in the reverse direction of chain movement to carry out weft hanging; controlling the weft laying trolley to move in the chain movement direction by the distance a, while controlling the slide table to move in the reverse direction of chain movement by the distance b, and controlling yarn to be discharged; and monitoring yarn tension reduction effect adjustment calculation parameters in the weft hanging process. Through the present application, the problem of excessive tension of weft laying and easy wear of a needle is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of warp knitting technology, and in particular to a method and system for controlling the laying of low-tension weft yarns. Background Technology

[0002] The production of fiberglass cloth is achieved through processes such as... Figure 1 The high-speed multiaxial warp knitting machine shown is used to process multiple fiberglass yarns into the final fiberglass cloth product. The main structure of the existing warp knitting machine includes a conveyor chain, a weft-laying carriage, and a slide table. In the warp knitting process, weft loading is an important step in introducing the weft yarn between the warp yarns to form a stable knitting structure. One weft loading action of the existing warp knitting machine is as follows: the weft-laying carriage first presses the weft yarn onto the needle block of the chain and the hook of the slide table. Then the chain moves forward at a constant speed, and the weft-laying carriage and the slide table carry the weft yarn quickly in the opposite direction of the chain movement. After reaching the target position for weft loading, the yarn is released, completing one weft loading action. The width of the weft loading is the weft-laying width. The standard configuration of a warp knitting machine is three-speed weft laying, corresponding to weft laying angles of +45°, 90°, and -45°. The angle between the weft laying carriage (weft direction) and the chain movement direction will be +45°, 90°, and -45°. During the weft laying process, the wrap angle formed by the yarn on the hook on the slide table becomes smaller and smaller, and the force on the hook becomes larger and larger. This not only causes the weft yarn to be stretched too tightly, resulting in excessive tension and affecting control performance, but also affects the service life of the mechanical mechanism. In particular, it increases the wear of the hook, causing the yarn to fray, the hook to break, and affecting the fabric quality. Summary of the Invention

[0003] This invention provides a low-tension weft yarn laying control method and system, which can effectively solve the problems in the background technology, reduce damage to the hook needle and the yarn itself, and improve the fabric quality.

[0004] The present invention provides a method for controlling the laying of low-tension weft yarn, comprising the following steps: S1: Obtain the current weft laying angle and weft laying width, and obtain the chain running speed, the current position of the weft laying carriage, and the current position of the slide table; S2: Based on the acquired data, calculate the current wrap angle of the yarn on the slide hook; S3: Determine the target wrap angle based on the current wrap angle and the preset wrap angle increment, and calculate the required weft laying trolley movement distance a and slide table movement distance b to achieve the target wrap angle; S4: Control the weft laying trolley to move a distance a in the opposite direction of the chain movement, and at the same time control the slide table to move a distance b in the direction of the chain movement; S5: Control the weft-laying trolley and the slide table to maintain a relative position distance of a+b, and move synchronously in the opposite direction of the chain movement to hang the weft; S6: Control the weft laying trolley to move a distance a along the chain movement direction, and simultaneously control the slide table to move a distance b in the opposite direction of the chain movement, and then output the yarn; S7: Monitor the yarn tension reduction effect during the weft hanging process and adjust the wrap angle increment according to the reduction effect.

[0005] Further, in step S2, the calculation of the current wrap angle of the yarn on the crochet hook is specifically as follows: Calculate the instantaneous center distance d = |Xcar - Xers| between the weft laying trolley and the slide table; Where Xcar is the current position of the weft laying trolley, and Xers is the current position of the slide table; The current wrap angle αcur = α0 - k·(d / Lref)·|sinθ|; Where α0 is the reference wrap angle, k is the scaling factor, Lref is the reference length, θ is the weft laying angle, and W is the weft laying width.

[0006] Further, in step S3, determining the target envelope angle and calculating the movement distances a and b specifically involves: Determine the target containment angle αtar = min(αmax, αcur + Δα); Where αmax is the maximum safe wrap angle, and △α is the wrap angle increment; Calculate the target distance between the two mechanisms required to reach αtar: dtar = ((α0 - αtar)·Lref) / (k·|sinθ|); Calculate the total compensation distance Δd = dtar - d; Based on the maximum accelerations Acar and Aers of the weft-laying trolley and the slide, calculate the distribution coefficient γ = Acar / (Acar + Aers); Then the distance the weft-laying trolley moves is a = △d·γ, and the distance the slide moves is b = △d·(1-γ).

[0007] Furthermore, α0 is obtained as follows: With the equipment stationary and without yarn threading, manually move the weft-laying carriage and slide to their furthest relative positions; use laser-simulated yarn paths to measure the angle formed by the theoretical contact point of the yarn and the center of the hook needle. This measured value is the reference wrap angle α0.

[0008] Furthermore, in step S4, the weft-laying trolley and the slide table are synchronously controlled to move along their respective trajectories, so that the two mechanisms complete their movements simultaneously at the end of step S4.

[0009] Furthermore, in step S5, the specific control method for the synchronous movement of the weft-laying carriage and the slide table is as follows: Plan the movement trajectory of the weft-laying trolley, which is a function of the weft-laying trolley's position and time; Establish a control cycle, and in each control cycle: Obtain the final position of the weft-laying trolley in the current control cycle; Calculate the final position of the slide table in the current control cycle based on the final position of the weft laying trolley; Move the slide to its final position at the end of the current control cycle.

[0010] Furthermore, in step S6, before yarn output, it is determined whether the absolute error between the actual position feedback value of the weft laying carriage and the slide table and the corresponding target position is less than a set threshold, and whether the absolute value of the actual speed feedback value of the weft laying carriage and the slide table is less than a set threshold; when both judgments pass and are maintained for a period of time, the yarn output action is then performed.

[0011] Furthermore, in step S7, the specific effect of monitoring the reduction in yarn tension during the weft insertion process is as follows: Real-time acquisition of yarn tension F(t) during weft insertion; Calculate the average value Favg of F(t) within one weft hanging cycle; Calculate the tension reduction rate η = (Fbase - Favg) / Fbase · 100%; Fbase represents the optimal yarn tension during the weft insertion process.

[0012] Furthermore, in step S7, the adaptive adjustment of the envelope angle increment specifically involves: Set a desired target tension reduction rate ηtar; Set the adaptive adjustment step size △stp; The system continuously records the tension reduction rate ηi for each production cycle. Whenever the adjustment trigger cycle is reached, the system calculates the moving average ηavg of ηi for the most recent N cycles. If ηavg < ηtar, then increase the wrap angle increment Δα by one step Δstp; If ηavg≥ηtar, then keep the wrap angle increment Δα unchanged.

[0013] The present invention also relates to a low-tension weft yarn laying control system, including a chain with needle blocks, a slide with hooks, and a weft laying carriage for hanging weft; the slide and the weft laying carriage both move horizontally, and the direction of movement is parallel to the direction of movement of the chain. It also includes a storage unit and a processor, the storage unit being used to store one or more program instructions; the processor being used to run one or more program instructions to perform the steps of the low-tension weft yarn laying control method described above.

[0014] The technical solution of this invention can achieve the following technical effects: This method establishes a quantitative model between the yarn wrap angle and the mechanism movement, and through precise dynamic control of the coordinated movement of the weft laying carriage and the slide table, inserts an active, opposite compensating movement in the early stage of the action without changing the total weft hanging time. This can actively increase and stabilize the yarn wrap angle on the hook during the weft hanging process, effectively reduce yarn tension, reduce damage to the hook and yarn, and improve fabric quality and equipment operation stability. Attached Figure Description

[0015] 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 recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of the control system for laying low-tension weft yarns; Figure 2 Comparison of the positions of the weft laying carriage and slide table before and after movement in the low-tension weft yarn laying control method; Attached diagram labels: 1. Chain; 2. Weft laying carriage; 3. Slide table. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] This invention relates to a low-tension weft yarn laying control method, comprising multiple steps S1 to S7. These steps enable real-time status monitoring and real-time calculation of control data. Based on the calculated parameters, the methods control the movement of the weft laying carriage 2 and the slide table 3 during weft yarn laying, thereby actively increasing and stabilizing the wrap angle of the yarn on the hook needle, effectively reducing yarn tension, and minimizing damage to the hook needle and yarn. The specific steps are as follows: S1: Obtain the current weft laying angle and weft laying width, and obtain the running speed of chain 1, the current position of weft laying trolley 2 and the current position of slide table 3; this step is the initialization stage before weft hanging, and its purpose is to obtain accurate process parameters and real-time equipment status to provide accurate reference for all subsequent calculations and controls.

[0020] S2: Based on the acquired data, the dynamic wrap angle, which is difficult to measure directly, is estimated online in real time using two easily obtainable parameters: the spacing between mechanisms and the weft laying angle. The current wrap angle of the yarn on the hook of the slide table 3 is calculated. The current wrap angle αcur of the yarn on the hook is a key physical quantity that directly affects the yarn tension and the force on the hook.

[0021] S3: Based on the current wrap angle and the preset wrap angle increment, compare the process optimization target (wrap angle increment) with the current state to determine the desired wrap angle for this weft insertion, and calculate the required weft laying trolley 2 moving distance a and slide table 3 moving distance b to achieve the target wrap angle.

[0022] The above steps are all preparatory work before weft insertion. After the calculations are completed, the formal weft insertion process begins: S4: Control the weft-laying carriage 2 to move a distance 'a' in the opposite direction of chain 1, and simultaneously control the slide 3 to move a distance 'b' in the direction of chain 1. Figure 2 As shown; this step is the pre-weft hanging stage. Through the synchronous back-to-back movement of the two mechanisms, the distance between them is actively increased, thereby rapidly increasing the yarn wrap angle and creating a low-tension starting condition for subsequent weft hanging.

[0023] S5: Control the weft laying trolley 2 and the slide table 3 to maintain a relative position distance interval of a+b, and move synchronously in the opposite direction of the chain 1 to hang the weft; this step is the middle section of weft hanging, and the core is to maintain the increased wrap angle constant (i.e. the two mechanisms maintain a relative position distance interval of a+b) to ensure that the entire laying process is carried out under low yarn tension.

[0024] S6: Control the weft-laying trolley 2 to move a distance a along the direction of chain 1, and at the same time control the slide table 3 to move a distance b in the opposite direction of chain 1, and then output the yarn; this step is the later stage of weft hanging, and the two mechanisms return to the theoretical end position of this weft hanging (i.e. the original target position), and then output the yarn.

[0025] S7: Monitor the yarn tension reduction effect during the weft hanging process and adjust the wrap angle increment according to the reduction effect; this step is based on historical effect data and automatically fine-tunes the core optimization parameters (wrap angle increment) so that the system can adapt to disturbances such as yarn batches and environmental changes and maintain optimal performance in the long term.

[0026] Preferably, in step S1, the operator sets or retrieves the core process parameters for this production from the formula library via the warp knitting machine's human-machine interface (HMI): the weft laying angle θ (one of +45°, 90°, or -45°) and the weft laying width W. After the parameters are set, the system collects real-time operating data before weft insertion: the real-time linear speed of chain 1 is calculated by reading the encoder pulse frequency of the main drive shaft servo motor; the real-time coordinate values ​​of the position detection sensors installed on the weft laying carriage and the slide rail are recorded as Xcar (weft laying carriage position) and Xers (slide position), respectively.

[0027] Preferably, in step S2, the calculation of the current wrap angle of the yarn on the crochet hook is specifically as follows: Calculate the instantaneous center distance d between the weft-laying trolley 2 and the slide table 3, which is d = |Xcar - Xers|. Where Xcar is the current position of the weft laying trolley 2, and Xers is the current position of the slide 3; The current formula for calculating the wrap angle αcur is a simplified model derived from geometric relationships and calibrated in practice: The current wrap angle αcur = α0 - k·(d / Lref)·|sinθ|; Where θ is the weft laying angle and W is the weft laying width.

[0028] α0 is the reference wrap angle, which is a constant determined by the mechanical structure of the equipment (such as the radius of the hook and the relative position of the yarn guide hole). It represents the natural wrap angle of the yarn on the hook when the two mechanisms are at their farthest distance.

[0029] k is a proportionality coefficient, which comprehensively reflects the degree of influence of the specific mechanical characteristics of this equipment (such as the slight non-parallelism of the guide rail and the elastic deformation of the yarn guide) on the change of the wrap angle; Lref is the reference length, usually half of the standard weft width W, used to normalize the variable d.

[0030] d is the instantaneous center distance between the weft laying carriage 2 and the slide table 3. The smaller the distance, the straighter the yarn is stretched, and the smaller the wrap angle is usually.

[0031] This computational model enables online real-time estimation of dynamic wrap angles, which are difficult to measure directly, using readily available position and angle parameters. To ensure model accuracy, α0 and k need to be obtained through specialized calibration experiments. The method for obtaining α0 is as follows: With the equipment stationary and without yarn threading, manually move the weft laying carriage 2 and the slide table 3 to the farthest position; use the yarn path simulated by laser to measure the angle formed by the theoretical contact point of the yarn and the center of the hook needle. This measured value is the reference wrap angle α0.

[0032] k is determined by dynamic calibration. That is, when the equipment is in the yarn-threading state, the proportional coefficient k is obtained by changing the spacing and simultaneously measuring the actual tension or wrap angle, and then using the least squares method to fit and solve for the proportional coefficient k that minimizes the sum of squares of the errors between the model prediction value and the measured value.

[0033] Preferably, in step S3, determining the target envelope angle and calculating the movement distances a and b specifically involves: Determine the target containment angle αtar = min(αmax, αcur + Δα); Wherein, αmax is the maximum safe wrap angle, which is the maximum wrap angle value under the premise of ensuring that the yarn will not unsnag or interfere with other components; △α is the wrap angle increment, which physically means the amount by which the current wrap angle is expected to be actively increased.

[0034] Calculate the target distance between the two mechanisms required to reach αtar: dtar = ((α0 - αtar)·Lref) / (k·|sinθ|); Calculate the total compensation distance Δd = dtar - d; Based on the maximum accelerations Acar and Aers of the weft-laying trolley 2 and the slide 3, calculate the distribution coefficient γ = Acar / (Acar + Aers); Then the distance the weft-laying trolley 2 moves is a = △d·γ, and the distance the slide 3 moves is b = △d·(1-γ).

[0035] This calculation model employs a strategy of allocating displacement proportionally based on maximum acceleration capability. This allows the mechanism with stronger dynamic performance (acceleration capability) to undertake more displacement, enabling the two axes to move more closely and simultaneously, thereby minimizing the motion time of the weft insertion section. The allocation coefficient γ is calculated based on this principle. Furthermore, the allocation strategy can also be adjusted according to actual needs, employing equal allocation (γ=0.5) or being directly specified, offering good flexibility.

[0036] Preferably, in step S4, before controlling the weft-laying carriage 2 and the slide table 3, the motion trajectories of the two mechanisms are planned and calculated to determine whether the movement trajectories of the weft-laying carriage 2 and the slide table 3 exceed the physical limits of their respective guide rails. If either exceeds the limit, the current process is immediately stopped and an overtravel alarm is triggered to prevent mechanical collisions. If the safety pre-check passes, the motion controller plans an S-shaped speed curve trajectory for each of the two mechanisms to ensure smooth movement and minimal impact. Then, the weft-laying carriage 2 and the slide table 3 can be synchronously controlled to move along their respective trajectories, so that the two mechanisms simultaneously reach their respective endpoints and complete the movement at the end of step S4.

[0037] Preferably, in step S5, the specific control method for the synchronous movement of the weft-laying carriage 2 and the slide table 3 is as follows: Plan the movement trajectory of the weft-laying trolley 2, which is a function of the position and time of the weft-laying trolley 2; Set a control cycle (e.g., 125 μs), and in each control cycle: Obtain the final position of the weft-laying trolley 2 in the current control cycle; Calculate the final position of slide 3 in the current control cycle based on the final position of the weft laying trolley 2; Move slide 3 to its final position at the end of the current control cycle.

[0038] The above control method divides the entire weft insertion section into multiple control cycles. Within each control cycle, the distance between the slide table 3 and the weft-laying carriage 2 is maintained at a+b at the end of the control cycle, thus ensuring that the slide table 3 can continuously maintain a+b distance to follow the weft-laying carriage 2 throughout the entire weft insertion section. During the movement, it is also necessary to monitor the deviation between the actual position and the commanded position of the slide table 3 in real time (i.e., the following error). If the following error exceeds the safety threshold (e.g., 0.5mm), an alarm is triggered and the machine stops to prevent yarn breakage or mechanical damage due to loss of synchronization.

[0039] Preferably, in step S6, before yarn output, it is determined whether the absolute error between the actual position feedback value of the weft laying trolley 2 and the slide table 3 and their corresponding target position is less than a set threshold, and whether the absolute value of the actual speed feedback value of the weft laying trolley 2 and the slide table 3 is less than a set threshold; only when both judgments pass and are maintained for a period of time to filter out instantaneous misjudgments caused by sensor noise or mechanical vibration can the yarn output action be performed.

[0040] Preferably, in step S7, the specific effect of monitoring the reduction of yarn tension during the weft hanging process is as follows: The yarn tension F(t) during the weft laying process is collected in real time. The yarn tension F(t) can be indirectly detected by the wrapping roller set on the weft laying trolley 2. Calculate the average value F(t) Favg within a weft hanging cycle. When calculating, select the tension data F(t) of the middle section of the weft hanging process (i.e. step S5) that best represents the stable laying process as the evaluation object, because the yarn laying process is stable at this stage. Calculate the arithmetic mean of F(t) of all sampling points within this time period to obtain the average tension Favg of this weft hanging.

[0041] Calculate the tension reduction rate η = (Fbase - Favg) / Fbase · 100%; Where Fbase represents the optimal yarn tension during weft insertion under the same process parameters as in this case. η is a positive number indicating an effective reduction in tension; a larger value indicates better control.

[0042] Preferably, in step S7, the adaptive adjustment of the envelope angle increment specifically involves: Set a desired target tension reduction rate ηtar; set an adaptive adjustment step size Δstp; set the evaluation window size N (e.g., 50 production cycles). The system continuously records the tension reduction rate ηi for each production cycle. Whenever the adjustment trigger cycle is reached (e.g., after a specified number of weft hanging actions are performed), the moving average ηavg of ηi for the most recent N cycles is calculated. Compare ηavg with ηtar: If ηavg < ηtar, it means that the current control effect has not achieved the expected goal. In this case, the wrap angle increment Δα is increased by one step Δstp to further reduce the tension by more aggressively increasing the wrap angle. To prevent the parameter from increasing indefinitely or oscillating, upper and lower limits [Δαmin, Δαmax] can be set for Δα. If ηavg≥ηtar, then keep the wrap angle increment △α unchanged to maintain stability.

[0043] This invention also relates to a low-tension weft yarn laying control system, such as Figure 1 As shown, it includes a chain 1 with needle blocks, a slide 3 with hooks, and a weft-laying carriage 2 for hanging weft; both the slide 3 and the weft-laying carriage 2 move horizontally, and their directions of movement are parallel to the direction of movement of the chain 1. It also includes a storage device and a processor. The storage device (such as ROM, Flash, or hard disk) is used to store one or more program instructions that encode all the control logic, algorithms, and parameter libraries of S1 to S7 above. The processor (such as the CPU of an industrial PLC, the processor of a dedicated motion controller, or the CPU of a multi-core industrial PC) is used to run one or more program instructions to execute the steps of the low-tension weft yarn laying control method described above.

[0044] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A method for controlling the laying of low-tension weft yarns, characterized in that the steps include... include: S1: Obtain the current weft laying angle and weft laying width, and obtain the chain running speed, the current position of the weft laying carriage, and the current position of the slide table; S2: Based on the acquired data, calculate the current wrap angle of the yarn on the slide hook; S3: Determine the target wrap angle based on the current wrap angle and the preset wrap angle increment, and calculate the required weft laying trolley movement distance a and slide table movement distance b to achieve the target wrap angle; S4: Control the weft laying trolley to move a distance a in the opposite direction of the chain movement, and at the same time control the slide table to move a distance b in the direction of the chain movement; S5: Control the weft-laying trolley and the slide table to maintain a relative position distance of a+b, and move synchronously in the opposite direction of the chain movement to hang the weft; S6: Control the weft laying trolley to move a distance a along the chain movement direction, and simultaneously control the slide table to move a distance b in the opposite direction of the chain movement, and then output the yarn; S7: Monitor the yarn tension reduction effect during the weft hanging process and adjust the wrap angle increment according to the reduction effect; In step S2, calculating the current wrap angle of the yarn on the crochet hook is specifically as follows: Calculate the instantaneous center distance d between the weft-laying trolley and the slide table: d = |Xcar - Xers|; Where Xcar is the current position of the weft laying trolley, and Xers is the current position of the slide table; The current wrap angle αcur = α0 - k·(d / Lref)·|sinθ|; Where α0 is the reference wrap angle, k is the proportional coefficient, Lref is the reference length, θ is the weft laying angle, and W is the weft laying width; In step S3, determining the target envelope angle and calculating the movement distances a and b are specifically as follows: Determine the target containment angle αtar = min(αmax, αcur + Δα); Where αmax is the maximum safe wrap angle, and △α is the wrap angle increment; Calculate the target distance between the two mechanisms required to reach αtar: dtar = ((α0 - αtar)·Lref) / (k·|sinθ|); Calculate the total compensation distance Δd = dtar - d; Based on the maximum accelerations Acar and Aers of the weft-laying trolley and the slide, calculate the distribution coefficient γ = Acar / (Acar + Aers); Then the distance the weft-laying trolley moves is a = △d·γ, and the distance the slide moves is b = △d·(1-γ).

2. The low-tension weft yarn laying control method according to claim 1, characterized in that, The method for obtaining α0 is as follows: With the equipment stationary and without yarn threading, manually move the weft-laying carriage and slide to their furthest relative positions; use laser-simulated yarn paths to measure the angle formed by the theoretical contact point of the yarn and the center of the hook needle. This measured value is the reference wrap angle α0.

3. The low-tension weft yarn laying control method according to claim 1, characterized in that, In step S4, the weft-laying trolley and the slide table are synchronously controlled to move along their respective trajectories, so that the two mechanisms complete their movements simultaneously at the end of step S4.

4. The low-tension weft yarn laying control method according to claim 1, characterized in that, In step S5, the specific control method for the synchronous movement of the weft-laying trolley and the slide table is as follows: Plan the movement trajectory of the weft-laying trolley, which is a function of the weft-laying trolley's position and time; Establish a control cycle, and in each control cycle: Obtain the final position of the weft-laying trolley in the current control cycle; Calculate the final position of the slide table in the current control cycle based on the final position of the weft laying trolley; Move the slide to its final position at the end of the current control cycle.

5. The low-tension weft yarn laying control method according to claim 1, characterized in that, In step S6, before yarn output, it is determined whether the absolute error between the actual position feedback value of the weft laying carriage and the slide table and the corresponding target position is less than a set threshold, and whether the absolute value of the actual speed feedback value of the weft laying carriage and the slide table is less than a set threshold. After both judgments are passed and maintained for a period of time, the yarn output action is performed.

6. The low-tension weft yarn laying control method according to claim 1, characterized in that, In step S7, the specific effect of monitoring the reduction in yarn tension during the weft insertion process is as follows: Real-time acquisition of yarn tension F(t) during weft insertion; Calculate the average value Favg of F(t) within one weft hanging cycle; Calculate the tension reduction rate η = (Fbase - Favg) / Fbase · 100%; Fbase represents the optimal yarn tension during the weft insertion process.

7. The low-tension weft yarn laying control method according to claim 6, characterized in that, In step S7, the adaptive adjustment of the envelope angle increment is specifically as follows: Set a desired target tension reduction rate ηtar; Set the adaptive adjustment step size △stp; The system continuously records the tension reduction rate ηi for each production cycle. Whenever the adjustment trigger cycle is reached, the system calculates the moving average ηavg of ηi for the most recent N cycles. If ηavg < ηtar, then increase the wrap angle increment Δα by one step Δstp; If ηavg≥ηtar, then keep the wrap angle increment Δα unchanged.

8. A low-tension weft yarn laying control system, characterized in that, It includes a chain with needle blocks, a slide with hooks, and a weft-laying carriage for attaching weft; both the slide and the weft-laying carriage move horizontally, and their directions of movement are parallel to the direction of movement of the chain. It also includes a storage device and a processor, the storage device being used to store one or more program instructions; the processor being used to run one or more program instructions to perform the steps of the low-tension weft yarn laying control method as described in any one of claims 1 to 7.

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