A method and apparatus for intelligent tension control of cable braiding machine

Abstract

This invention relates to the field of tension control technology, specifically to an intelligent tension control method and device for a cable braiding machine. In the steady-state operation phase, the method involves: determining the corresponding target angle zone number based on the real-time spindle revolution angle within each revolution cycle; determining the net load torque based on the target reference load current and real-time load current corresponding to the target angle zone number; determining the track sector and sector number to which the spindle belongs based on the real-time spindle revolution angle; performing angular domain integration on the net load torque corresponding to the same sector number based on the change in the real-time spindle revolution angle to determine the historical resistance index corresponding to the track sector; outputting a feedforward compensation amount to the servo motor based on the target reference load current; if the difference between the real-time revolution angle and the starting revolution angle of the next track sector is less than a preset angle threshold, reading the target historical resistance index; if the target historical resistance index exceeds an alarm threshold, performing tension adjustment, thereby improving the reliability of tension control.

Description

Technical Field

[0001] This invention relates to the field of tension control technology, specifically to an intelligent tension control method and device for a cable braiding machine. Background Technology

[0002] Cable braiding machines are key equipment in the manufacture of shielded cables. During operation, multiple wire-carrying spindles need to move in high-speed planetary orbits around the cable core. As the physical posture of the spindles changes periodically with the orbital position, the tangential component of gravity acting on them fluctuates sinusoidally within the revolution period. Furthermore, the centrifugal force at the intersection of the orbits will change abruptly with the rotation radius, resulting in a deterministic mechanical resistance wave in the servo system load that is strictly locked to the spatial position.

[0003] Existing tension control technologies mostly rely on PID feedback regulation. However, under high-speed conditions, PID control exhibits phase lag in its response to periodic mechanical disturbances, easily leading to periodic stripes of varying density on the braided layer surface, affecting product quality. Simultaneously, mechanical faults such as localized wear of the guide rail or foreign object jamming can cause abnormally high resistance at specific locations. Current technologies struggle to distinguish between abnormal mechanical resistance and abnormal wire tension, and are susceptible to false alarms caused by inertial torque during spindle acceleration and deceleration. This results in situations where a constant high tension is forcibly maintained in high-resistance regions with abnormal mechanical resistance. Consequently, the electromagnetic torque output by the servo motor, combined with the mechanical resistance, can easily exceed the wire's yield strength, leading to hidden microscopic damage or direct breakage of the wire. Summary of the Invention

[0004] To address the technical problem of difficulty in distinguishing between abnormal mechanical resistance and abnormal tension in the wire itself, which leads to the inability to adjust tension in a timely manner, this invention provides an intelligent tension control method and device for cable braiding machines. The specific technical solution adopted is as follows: This invention proposes an intelligent tension control method for cable braiding machines, the method comprising: Initialization phase: During multiple consecutive spindle revolution cycles, the spindle revolution angle is divided to obtain multiple angle zones and corresponding angle zone numbers, and the load current is collected synchronously; the load currents belonging to the same angle zone number are processed to determine the reference load current corresponding to each angle zone number. Steady-state operation phase: Within each revolution cycle, the corresponding target angle zone number is determined based on the real-time spindle revolution angle; the net load torque is determined based on the target reference load current and real-time load current corresponding to the target angle zone number. Based on the real-time spindle revolution angle, the track sector and sector number to which it belongs are determined from multiple preset track sectors and their corresponding sector numbers; based on the change in the real-time spindle revolution angle, the net load torque corresponding to the same sector number is integrally calculated in the angular domain to determine the historical resistance index corresponding to the track sector. Based on the target reference load current, the servo motor outputs a feedforward compensation amount; if the difference between the real-time revolution angle and the starting revolution angle of the next track sector is less than the preset angle threshold, the target historical resistance index generated in the previous revolution cycle and corresponding to the next track sector is read; if the target historical resistance index exceeds the preset alarm threshold, tension adjustment is performed during the process of the spindle switching to the next track sector.

[0005] Furthermore, the spindle revolution period refers to the time it takes for the spindle to revolve 360 ​​degrees around the cable core; the calculation process for the spindle revolution angle includes: Read the absolute position encoder signal of the spindle servo motor to obtain the current spindle angle value, and record it as the spindle angle; Multiply the spindle angle by the preset transmission ratio coefficient to obtain the cumulative rotation angle value of the spindle disk from the reference zero point; The spindle revolution angle is obtained by performing a modulo 360-degree calculation on the cumulative rotation angle value.

[0006] Furthermore, the process of dividing the spindle's revolution angle to obtain multiple angular zones and corresponding angular zone numbers includes: The complete angular range of the spindle's revolution cycle is divided into a preset number of continuous angular intervals. Each angular interval is defined as an angular partition, and each angular partition is assigned a unique integer number in sequence as the angular partition number. Divide the spindle's revolution angle by 360 degrees, and multiply the quotient by the total number of angle partitions to obtain a real number result. Round the real number down to obtain the angle zone number corresponding to the spindle's revolution angle.

[0007] Further, the process of processing load currents belonging to the same corner zone number to determine the reference load current corresponding to each corner zone number includes: For each spindle revolution cycle, at each servo control moment within the spindle revolution cycle, the load current value is collected, and the angle zone number corresponding to the spindle revolution angle at the servo control moment is collected; wherein, the servo control moment is a constant fixed time interval shorter than the spindle revolution cycle. The load current value is accumulated into a temporary accumulation variable associated with the same corner zone number, and the sampling count of the corner zone number is incremented by one; After completing the data acquisition for multiple consecutive full revolution cycles, for each corner zone number, the corresponding temporary cumulative variable is divided by the number of samplings corresponding to the corner zone number to obtain the reference load current corresponding to the corner zone number. Store the reference load current corresponding to all corner zone numbers in the reference load current lookup set according to the corner zone number order.

[0008] Furthermore, the process of determining the net load torque includes: For each servo control moment in each revolution cycle, the target angle zone number is calculated based on the real-time spindle revolution angle; From the lookup set of reference load currents, find the target reference load current that matches the target corner zone number; The net load torque is obtained by nonnegating the absolute difference between the real-time load current and the target reference load current.

[0009] Furthermore, the process for determining the historical resistance index includes: Divide the real-time spindle revolution angle by 360 degrees, and multiply the quotient by the total number of preset track sectors to obtain the real value; perform a floor operation on the real value to obtain the sector number to which the real-time spindle revolution angle belongs; For each servo control moment in each revolution cycle, the spindle revolution angle collected at the previous servo control moment is obtained as a comparison spindle revolution angle. Calculate the algebraic difference between the real-time spindle revolution angle and the comparison spindle revolution angle; if the absolute value of the algebraic difference is greater than 180 degrees, subtract 360 degrees from the positive algebraic difference to obtain the final algebraic difference; add 360 degrees to the negative algebraic difference to obtain the final algebraic difference; if the absolute value of the algebraic difference is not greater than 180 degrees, directly use the algebraic difference; use the final algebraic difference as the revolution angle change at the moment of servo control; Multiply the change in revolution angle at each servo control moment by the net load torque to obtain the cumulative resistance characteristic value; based on the sector number to which the spindle revolution angle belongs, accumulate the absolute value of the calculated cumulative resistance characteristic value into an accumulation register dedicated to the same sector number. If a sector number change is detected, the final accumulated value in the accumulator register corresponding to the sector number before the change will be used as the historical resistance indicator corresponding to the sector number before the change; and the value of the accumulator register corresponding to the sector number before the change will be cleared to zero.

[0010] Furthermore, the step of outputting feedforward compensation to the servo motor based on the target reference load current includes: Obtain the real-time current regulation calculated by the tension feedback controller; The sum of the target reference load current and the real-time current regulation is calculated as the final current regulation. The final current adjustment value is sent to the servo driver as the current command at the current moment.

[0011] Furthermore, if the difference between the real-time revolution angle and the starting revolution angle of the next orbital sector is less than a preset angle threshold, the target historical resistance index generated in the previous revolution cycle and corresponding to the next orbital sector is read, including: Increment the sector number to which the real-time spindle revolution angle belongs by one to obtain the target sector number of the next track sector. If the result of incrementing the sector number by one is equal to the total number of sectors, the target sector number is set to zero. Multiply the target sector number by the preset standard angle span of a single sector to obtain the starting angle value of the next track sector. Based on the difference between the starting angle value of the next track sector and the real-time spindle revolution angle, the angle difference is obtained; it is determined whether the angle difference is less than the preset angle threshold; if the angle difference is less than the preset angle threshold, the sector switching pre-read operation is triggered. In the previous complete orbital cycle, the target sector number is used as an index to find the data element corresponding to the index. The data element is the historical resistance index calculated and stored for the corresponding orbital sector. Use the identified historical resistance indicators as the target historical resistance indicators.

[0012] Furthermore, if the target historical resistance index exceeds a preset alarm threshold, tension adjustment is performed during the spindle switching to the next track sector, including: If the target historical resistance index exceeds the preset alarm threshold, the preset original target tension value is multiplied by the preset reduction coefficient to obtain the target tension setting value; If the real-time spindle revolution angle is detected to reach or exceed the starting angle value of the next track sector for the first time, it is determined that the real-time spindle revolution angle has actually entered the next track sector, and the target input value of the tension controller is switched from the original target tension value to the target tension set value. If the real-time spindle revolution angle is detected to reach or exceed the termination angle value of the next track sector for the first time, it is determined that the spindle revolution angle has left the next track sector, and the target input value of the tension controller is switched from the target tension set value back to the original target tension value.

[0013] A smart tension control device for a cable braiding machine includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of a smart tension control method for a cable braiding machine.

[0014] The present invention has the following beneficial effects: In the initialization phase, this invention divides the spindle into zones based on its revolution angle, establishing a dedicated reference load current for each zone. This accurately captures the load reference characteristics at different angles, enabling the matching of the target reference load based on the real-time revolution angle during steady-state operation. This separates the net load torque that truly reflects tension fluctuations, making subsequent tension adjustments more aligned with actual load changes. This effectively counteracts the interference of periodic load fluctuations during revolution, significantly reducing the probability of instantaneous tension overload or underload, and improving the uniformity of the braided layer and product quality. Historical resistance indicators for each track sector are generated through angular domain integration calculations. Combined with a pre-reading mechanism before sector switching, the resistance characteristics of the next sector are obtained in advance, i.e., the target historical resistance indicator corresponding to the next track sector is extracted. If the target historical resistance indicator exceeds the alarm threshold, tension adjustment is actively performed during sector switching, breaking the limitations of post-event feedback and transforming tension adjustment from a passive response to an active prediction. Considering the phase lag caused by periodic mechanical disturbances, this effectively suppresses tension impacts during sector switching, further improving the stability and reliability of tension control. Attached Figure Description

[0015] To more clearly illustrate the technical solutions and advantages 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.

[0016] Figure 1 A flowchart of an intelligent tension control method for a cable braiding machine provided in one embodiment of the present invention; Figure 2 This is an example diagram illustrating the process of determining historical resistance indicators according to an embodiment of the present invention. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of an intelligent tension control method and apparatus for a cable braiding machine according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[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.

[0019] The following description, in conjunction with the accompanying drawings, details the specific scheme of the intelligent tension control method and device for cable braiding machines provided by the present invention.

[0020] Please see Figure 1 The diagram illustrates a flowchart of an intelligent tension control method for a cable braiding machine according to an embodiment of the present invention. The method includes: S101: Initialization phase: During multiple consecutive spindle revolution cycles, the spindle revolution angle is divided to obtain multiple angle zones and corresponding angle zone numbers, and the load current is collected synchronously; the load current belonging to the same angle zone number is processed to determine the reference load current corresponding to each angle zone number.

[0021] It should be noted that the cable braiding machine should be started before... The initialization phase is defined as the number of complete revolution periods. When the number of complete revolution periods detected is not less than [number missing], [further action is taken]. When the initialization phase ends, the system enters the steady-state operation phase. During the initialization phase, angle division and load current acquisition are performed for each spindle revolution cycle.

[0022] It should be noted that the specific value of N can be determined according to actual needs, and this embodiment does not impose a specific limitation. For example, in order to collect a sufficient amount of data, N can be set to 5.

[0023] It should be noted that the spindle revolution period refers to the time it takes for the spindle to revolve 360 ​​degrees around the cable core. For example, the zero-position pulse (Z-phase signal) emitted by the spindle encoder once per revolution can be used as a physical synchronization reference. Whenever the Z-phase signal is detected, the calculated spindle revolution angle is forcibly reset to 0°, thereby accurately calibrating the start and end points of each revolution period.

[0024] To accurately obtain the spindle revolution angle, as an example, the absolute position encoder signal of the spindle servo motor is read to obtain the current spindle angle value, which is recorded as the spindle angle; the spindle angle is multiplied by the preset transmission ratio coefficient to obtain the cumulative rotation angle value of the spindle disk from the reference zero point; the cumulative rotation angle value is calculated modulo 360 degrees to obtain the spindle revolution angle.

[0025] As can be understood, an absolute position encoder is a sensor installed on the servo motor shaft. It can directly read the precise angular position of the motor shaft within the current 360-degree circumference at any time, and is the direct source of obtaining the spindle angle.

[0026] It should be noted that the preset transmission ratio coefficient is a dimensionless fixed value, representing the actual number of rotations of the spindle disc for every one rotation of the main spindle motor. The specific value of the preset transmission ratio coefficient is a known parameter determined by the mechanical design and is fixed at the time the cable braiding machine leaves the factory. For example, if the main spindle rotates 16 times and the spindle disc rotates 1 time, the transmission ratio coefficient is usually expressed as 1 / 16.

[0027] It should be noted that the modulo 360° operation is specifically divided by 360° and the remainder is taken. The purpose of this operation is to convert the cumulative rotation angle value into an angle value that always changes cyclically between 0° and 360°, that is, the spindle revolution angle.

[0028] Load current refers to the current corresponding to the real-time output torque of the servo motor that drives the spindle of the braiding machine. Load current reflects the amount of "force" that the servo motor needs to exert to overcome all resistances (including: the gravity and centrifugal force of all spindles, track friction, wire tension, etc.).

[0029] It should be noted that the load current can be acquired using existing mature technologies, and the specific process will not be elaborated here. For example, it can be directly read by the upper-level controller at each servo control moment (e.g., every 0.1 milliseconds) via fieldbus or analog signals.

[0030] It is important to understand that, since there is a continuous and precise correspondence between the load current of the servo motor and the spatial angular position of the spindle (such as the sinusoidal change of the gravitational component), and there are multiple continuous angles, it is not possible to directly store an independent reference value for each of the multiple continuous angles. Therefore, the continuous 360-degree circle can be discretized into a finite number of angle partitions and each angle partition can be assigned a unique angle partition number. In this way, only one reference load current representing the angle partition needs to be stored for each angle partition number. The load current value at any angle can be approximately obtained by querying the number in real time, thereby transforming the complex continuous spatial modeling problem into an efficient table lookup index problem.

[0031] In this embodiment, the complete angular range of the spindle's revolution period is divided into a preset number of continuous angular intervals. Each angular interval is defined as an angular partition, and each angular partition is assigned a unique integer number in sequence as the angular partition number. The spindle's revolution angle value is divided by 360 degrees, and the quotient is multiplied by the total number of angular partitions to obtain a real number result. The real number result is rounded down to obtain the angular partition number corresponding to the spindle's revolution angle.

[0032] It should be noted that the specific value of the preset number can be determined based on the actual control accuracy requirements and storage capacity. This embodiment does not impose a specific limitation. Generally, the more angle partitions there are, the more detailed the description of the angle space and the higher the control accuracy. However, at the same time, the amount of data that needs to be stored is also larger. For example, a common value for the preset number is 360. Choosing 360 means that each angle partition corresponds to 1 degree of arc length. In most industrial scenarios, its accuracy is sufficient to distinguish the load changes caused by gravity.

[0033] For example, when the real-time spindle revolution angle is 359.9°, it falls within the angle range of [359°, 360°), so the corresponding angle zone number is 359. It can be understood that the angle zone number is exactly equal to the lower integer limit (degrees) of the angle range it represents.

[0034] It's important to understand that the spindle's revolution angle is a continuous physical quantity, covering a circle from 0° to 360°. Angle partitioning is a finite number of discrete intervals obtained by uniformly dividing this circle from 0° to 360°. Each angle partition corresponds to a unique integer angle partition number. Therefore, it can be understood that the correspondence between the spindle's revolution angle and the angle partition is a many-to-one mapping: all spindle revolution angle values ​​within the same angle partition (such as the angle between 120.0° and 121.0°) within a continuous angle range will be mapped to the same angle partition number (such as angle partition number 120).

[0035] In this embodiment, for each spindle revolution cycle, at each servo control moment within the spindle revolution cycle, the load current value is collected, and the angle zone number corresponding to the spindle revolution angle at the servo control moment is also collected; wherein, the servo control moment is a constant fixed time interval shorter than the spindle revolution cycle; the load current value is accumulated into a temporary accumulated variable associated with the same angle zone number, and the sampling count of the angle zone number is incremented by one; after completing the data collection for multiple consecutive complete revolution cycles, for each angle zone number, the temporary accumulated variable corresponding to it is divided by the sampling count corresponding to the angle zone number to obtain the reference load current corresponding to the angle zone number; the reference load currents corresponding to all angle zone numbers are stored in the order of the angle zone numbers as a lookup set of reference load currents.

[0036] Servo control moment refers to the process of periodically acquiring and calculating the reference load current at an extremely high and fixed frequency (e.g., 1 kHz) within any spindle revolution cycle. The time interval of servo control moment is much smaller than the time of one revolution of the spindle (i.e., revolution cycle).

[0037] It is important to understand that, due to the presence of multiple spindles, the total load current value of the spindle servo motor is collected. During the initialization phase, this total load current value includes the superposition effect of the inherent resistance of all spindles. Therefore, the reference load current obtained by multi-cycle synchronous averaging is actually the current equivalent of the resultant torque of the inherent load of all spindles at the corresponding angular position. The reference load current reflects an overall average model, which is used for subsequent unified feedforward compensation of the spindle.

[0038] S102: Steady-state operation stage: During each revolution cycle, the corresponding target angle zone number is determined based on the real-time spindle revolution angle; the net load torque is determined based on the target reference load current and real-time load current corresponding to the target angle zone number.

[0039] It should be noted that the specific process of calculating the corner zone number based on the real-time spindle revolution angle can be found in the relevant description in step S101, and will not be repeated in this embodiment.

[0040] It should be noted that the steady-state operation stage is mainly applicable to the production stage where the spindle speed is constant.

[0041] It's important to understand that the load current value of a servo motor contains both inherent loads (such as gravity and centrifugal force) that fluctuate significantly due to the mechanical structure, and abnormal loads that require close monitoring (such as mechanical failures or abnormal wire tension). Therefore, it's necessary to separate these periodic fluctuations. This is done by subtracting the target reference load current, which is queried based on the current spatial location, from the real-time load current, thus isolating the pure load signal that reflects sudden problems or process anomalies. This is the net load torque.

[0042] In this embodiment, for each servo control moment in each revolution cycle, the target angle zone number is calculated based on the real-time spindle revolution angle; the target reference load current matching the target angle zone number is found from the lookup set of reference load currents; the absolute difference between the real-time load current and the target reference load current is non-negatively processed to obtain the net load torque.

[0043] It should be noted that the lookup set for the reference load current is usually a one-dimensional array in the computer. The subscript (index) of the array is the corner zone number, and the value stored in each element of the array is the reference load current corresponding to the corner zone number. Therefore, by using the "target corner zone number" calculated in real time as the array subscript, the corresponding array element in memory can be directly accessed, and the value retrieved is the required "target reference load current".

[0044] It should be noted that if the real-time load current is greater than the target reference load current, the absolute difference between the real-time load current and the target reference load current will be used as the net load torque; if the real-time load current is less than or equal to the target reference load current, the net load torque will be set to zero.

[0045] S103: Based on the real-time spindle revolution angle, determine the track sector and sector number to which it belongs from multiple preset track sectors and their corresponding sector numbers; based on the change in the real-time spindle revolution angle, perform angular domain integration on the net load torque corresponding to the same sector number to determine the historical resistance index corresponding to the track sector.

[0046] It should be noted that the circular track of the weaving machine is divided into multiple track sectors, and each track sector is assigned a unique sector number.

[0047] The division process can be determined based on the physical structural characteristics of the circular track of the braiding machine. The division criteria usually include: using the joint of each independent guide rail as the natural boundary; special locations such as the inlet and outlet of the wire, the tension detection wheel installation area, etc.; and dividing areas that are known to be easily worn or require key monitoring independently.

[0048] The sector number is a sequential integer number assigned to these physical structures (e.g., 0, 1, 2...), and the sector number directly corresponds to a specific physical track on the weaving machine.

[0049] For example, suppose the circular track of a weaving machine is made up of 12 identical arc-shaped guide rails. The division method is as follows: the total number of sectors is preset to 12; the sector numbers are 0, 1, 2, ..., 11; each sector number physically corresponds to a guide rail: sector 0 corresponds to the 1st guide rail, sector 1 corresponds to the 2nd guide rail, ..., sector 11 corresponds to the 12th guide rail. Each sector spans 360° / 12 = 30°, where 30° is the angular span. For example, sector 0: 0° ≤ angle < 30°, sector 1: 30° ≤ angle < 60°, ..., sector 11: 330° ≤ angle < 360°.

[0050] It should be noted that the angle partition is a fine-grained division (e.g., one angle partition for every 1 degree); the track sector is a coarse-grained division (e.g., one track sector for each section of the guide rail). However, both the sector number and the angle partition number are derived from the discretized mapping of the spindle's revolution angle. It can be understood that a track sector (e.g., 30 degrees) contains multiple consecutive angle partitions (e.g., 30).

[0051] It is important to understand that since the net load torque reflects the instantaneous magnitude of the abnormal load, it cannot characterize the continuous action and cumulative effect of abnormal resistance within a certain track area. Therefore, spatial domain integration can be performed on the track area. That is, by multiplying the net load torque calculated at each servo control moment within the same sector by the corresponding small angle increment (i.e., the change in revolution angle), the cumulative resistance characteristic value is obtained. All cumulative resistance characteristic values ​​within the same sector within the revolution cycle are then summed to obtain a cumulative energy value that is only related to the physical characteristics of the sector and is completely decoupled from the spindle speed. This value is used to quantify the mechanical health status of the area where the cumulative resistance characteristic value is located, i.e., the historical resistance index.

[0052] The process of determining historical resistance indicators is as follows: Figure 2 As shown, it includes: S103-1: Divide the real-time spindle revolution angle by 360 degrees, and multiply the quotient by the total number of preset track sectors to obtain a real value; perform a floor operation on the real value to obtain the sector number to which the real-time spindle revolution angle belongs.

[0053] It should be noted that the specific value of the total number of preset track sectors is determined by the mechanical physical structure, rather than being a freely chosen parameter. Each divided track sector corresponds to a physical track segment with independent mechanical significance, and the number of divided physical segments is the total number of preset track sectors. This embodiment will not elaborate further.

[0054] S103-2: For each servo control moment in each revolution cycle, obtain the spindle revolution angle collected at the previous servo control moment, and use it as the comparison spindle revolution angle.

[0055] It should be noted that if it is the first servo control moment after startup, since there is no spindle revolution angle collected in the previous servo control moment, the spindle revolution angle will be initialized to the real-time spindle revolution angle value read at the current moment.

[0056] S103-3: Calculate the algebraic difference between the real-time spindle revolution angle and the comparison spindle revolution angle; if the absolute value of the algebraic difference is greater than 180 degrees, subtract 360 degrees from the positive algebraic difference to obtain the final algebraic difference; add 360 degrees to the negative algebraic difference to obtain the final algebraic difference; if the absolute value of the algebraic difference is not greater than 180 degrees, directly use the algebraic difference; use the final algebraic difference as the revolution angle change at the moment of servo control.

[0057] It is understandable that, since the orbital angle of the comparison spindle is initialized to the real-time orbital angle value read at the current moment during the first servo control moment, the calculated algebraic difference is zero. This means that the change in orbital angle is set to zero during the first servo control moment.

[0058] It's important to understand that because the encoder feedback angle is a cyclic value (0° and 360° are equivalent), directly subtracting the real-time spindle revolution angle from the comparison spindle revolution angle will not identify the actual minute displacement when crossing the 0° boundary. For example, from 359° to 1°, the algebraic difference obtained by direct subtraction is -358°, but this does not represent a 358° reversal, but rather a 2° forward rotation. Therefore, the above-mentioned "addition and subtraction of 360° correction" is required: if the absolute value of the original algebraic difference exceeds 180°, it means that the calculation is misled by the cyclic boundary. By adding and subtracting 360° correction, the algebraic difference is pulled back to the [-180°, 180°] range, thus obtaining the final algebraic difference.

[0059] For example, suppose the final algebraic difference is -15°, which reflects that the spindle actually rotated 1.5 degrees in the opposite direction, where the sign indicates the direction and the absolute value indicates the magnitude.

[0060] The change in revolution angle refers to the actual angular displacement of the spindle as it revolves around the cable core within a very short servo control moment (e.g., 0.1 milliseconds). A smaller absolute value of the change in revolution angle at a given servo control moment indicates that the spindle is more likely operating at low speed or braking. To avoid artificially inflating errors due to long integration time when passing a fault point at low speed, even if the net load torque is large (e.g., severe jamming), a smaller absolute value of the change in revolution angle will result in a smaller cumulative resistance characteristic value calculated subsequently at that servo control moment.

[0061] It is important to understand that since the historical resistance index is used to reflect the total energy consumed by abnormal resistance, this total energy is obtained by summing up all resistance cumulative characteristic values ​​(regardless of whether they are positive or negative). It is known that the net load torque is always positive, and the sign of the resistance cumulative characteristic value mainly depends on the sign of the change in the revolution angle. Moreover, the sign of the change in the revolution angle indicates whether the resistance is doing positive or negative work (for example, a negative change in the revolution angle indicates that the resistance is doing negative work). Therefore, the sign of the change in the revolution angle ensures that the power consumption is also correctly recorded in the reverse motion segment.

[0062] S103-4: Multiply the change in revolution angle at each servo control moment by the net load torque to obtain the cumulative resistance characteristic value; based on the sector number to which the spindle revolution angle belongs, accumulate the absolute value of the calculated cumulative resistance characteristic value into an accumulation register dedicated to the same sector number.

[0063] It should be noted that the common unit for the change in revolution angle is "degree", while the unit for net load torque is "newton-meter" (N·m). In the International System of Units (SI), the unit of work, "joule" (J), is defined as 1 N·m·rad. Therefore, if the change in revolution angle is in "degree", it must first be converted to "radian" (rad). The specific conversion formula is a common technical method, which will not be elaborated in this embodiment.

[0064] Net load torque refers to the torque component remaining after subtracting the target reference load current (e.g., load current consumed by gravity or centrifugal force) determined by the mechanical structure corresponding to the current spatial position from the real-time load current of the servo motor. A larger net load torque at a given servo control moment indicates a more likely abnormal load and a higher risk signal. This means the motor output torque and mechanical resistance are more likely to be superimposed, making it easier to exceed the wire yield limit. In this case, forcibly maintaining a high target tension increases the risk of wire breakage. For example, a larger net load torque may indicate: localized wear, deformation, foreign object jamming, or poor lubrication in the track sector where the spindle is located, leading to a sharp increase in frictional resistance; excessive wire tension output by the spindle, requiring the motor to output greater torque to tighten the wire; or the wire being subjected to instantaneous pulling or impact.

[0065] S103-5: If a sector number change is detected, the final accumulated value in the accumulator register corresponding to the sector number before the change will be used as the historical resistance indicator corresponding to the sector number before the change; and the value of the accumulator register corresponding to the sector number before the change will be cleared to zero.

[0066] It should be noted that a sector number jump means that the sector number to which the real-time spindle revolution angle belongs changes abruptly from one integer value to another adjacent integer value. This signifies that the spindle has moved from one orbital sector to the next in physical space.

[0067] For example, the moment the sector number is detected to jump from 0 to 1, two key operations are immediately executed: Data settlement: The total value in the accumulator register corresponding to sector number 0 (i.e., the sum of the absolute values ​​of the accumulated resistance characteristic values ​​accumulated by the spindle in sector number 0) is used as the historical resistance index corresponding to sector number 0; then, the accumulator register of sector number 0 is cleared to prepare for recording the data when the spindle passes through sector number 0 again in the next revolution (i.e., the next orbital period).

[0068] S104: Based on the target reference load current, output the feedforward compensation amount to the servo motor; if the difference between the real-time revolution angle and the starting revolution angle of the next track sector is less than the preset angle threshold, read the target historical resistance index generated in the previous revolution cycle and corresponding to the next track sector; if the target historical resistance index exceeds the preset alarm threshold, perform tension adjustment during the process of the spindle switching to the next track sector.

[0069] In this embodiment, the real-time current regulation amount calculated by the tension feedback controller is obtained; the sum of the target reference load current and the real-time current regulation amount is calculated as the final current regulation amount; the final current regulation amount is sent to the servo driver as the current command at the current moment.

[0070] It is understood that, in this invention, the tension feedback controller typically refers to a PID controller.

[0071] It should be noted that the final current adjustment is for the current moment. After the final current adjustment is determined, it is immediately used as the command output for the current servo control moment to synchronously offset the load disturbance at the current moment and achieve real-time control without lag.

[0072] As an example, the real-time current regulation can be obtained using a standard PID (proportional-integral-derivative) feedback control algorithm. For instance, the specific process involves a tension sensor measuring the actual tension of the wire in real time, the controller comparing the measured actual tension with a preset target tension, and calculating the tension error. Then, the PID algorithm calculates a current value in real time based on the magnitude (proportional term), duration (integral term), and trend of the tension error (derivative term), which is the real-time current regulation.

[0073] It should be noted that the specific value of the preset target tension depends on the physical properties of the wire and the performance requirements of the final product, and is determined by the staff based on actual needs. This embodiment does not impose a specific limitation. For example, for a fine copper wire shielding layer, it may be set between 0.5N and 2N.

[0074] In this embodiment, the sector number to which the real-time spindle revolution angle belongs is incremented by one to obtain the target sector number of the next orbital sector. If the result of incrementing the sector number equals the total number of sectors, the target sector number is reset to zero. The target sector number is multiplied by the preset standard angle span of a single sector to obtain the starting angle value of the next orbital sector. The angle difference is obtained based on the difference between the starting angle value of the next orbital sector and the real-time spindle revolution angle. It is determined whether the angle difference is less than a preset angle threshold. If the angle difference is less than the preset angle threshold, a sector switching pre-read operation is triggered. In the immediately preceding complete revolution cycle, the data element corresponding to the index is found using the target sector number as an index. The data element is the historical resistance index calculated and stored for the corresponding orbital sector. The found historical resistance index is used as the target historical resistance index.

[0075] For example, suppose the sector number to which the real-time spindle revolution angle belongs at the current moment is 0, and the standard angle span is 30°. Then, sector number 0 corresponds to the first track sector (from 0° to 30°). Add one to sector number 0 to get 1, and then multiply 1 by the standard angle span (30°). Then the starting angle value of the next track sector is 30°. That is, sector number 1 corresponds to the starting angle value of the second track sector.

[0076] It should be noted that resetting the target sector number to zero indicates that it has entered the next revolution, that is, the next revolution cycle. At this time, there is no need to perform the process of calculating the angle difference - angle difference judgment. Just look up the target's historical resistance index. The subsequent operation of looking up the target's historical resistance index is exactly the same as the above situation.

[0077] It should be noted that, in order to avoid deadlock due to "pre-reading" across zero degrees, such as when the real-time spindle revolution angle is 359° and the starting angle of the next track sector is 0°, directly subtracting the two will result in a negative number. Therefore, it is also necessary to handle the boundary jump problem of circular motion and perform a modulo operation, i.e. (starting angle of the next track sector - real-time spindle revolution angle + 360°) ÷ 360°.

[0078] It should be noted that the specific value of the preset angle threshold can be determined by balancing the device's response time, servo control time, and spindle revolution speed. Generally speaking, the time taken for the angle travel corresponding to the preset angle threshold must be greater than or equal to the maximum time required for the device to complete the complete logical chain of "pre-reading data, decision calculation, and instruction issuance". For example, on a high-speed knitting machine, a smaller value (such as 2°) may be used; at low speeds or when the controller's calculation speed is slow, a larger value (such as 10°) may be used.

[0079] It is important to understand that if the historical resistance index exceeds the preset alarm threshold, it indicates that there is high mechanical resistance (such as wear or jamming) in the corresponding track sector. If the original high target tension is maintained in the area where the track sector is located, the total torque output by the servo motor to overcome the dual load of wire tension and mechanical resistance is more likely to exceed the yield strength limit of the wire. Therefore, at this time, the target tension setting value can be actively reduced to avoid the wire being overloaded and damaged or broken. Under the premise of ensuring production continuity, the safety of equipment and materials should be prioritized.

[0080] In this embodiment, if the target historical resistance index exceeds the preset alarm threshold, the preset original target tension value is multiplied by the preset derating coefficient to obtain the target tension setting value; if the real-time spindle revolution angle is detected to reach or exceed the starting angle value of the next track sector for the first time, it is determined that the real-time spindle revolution angle has actually entered the next track sector, and the target input value of the tension controller is switched from the original target tension value to the target tension setting value; if the real-time spindle revolution angle is detected to reach or exceed the ending angle value of the next track sector for the first time, it is determined that the spindle revolution angle has left the next track sector, and the target input value of the tension controller is switched from the target tension setting value back to the original target tension value.

[0081] It can be understood that the track sector termination angle value = track sector start angle value + preset standard angle span.

[0082] It should be noted that the specific value of the preset alarm threshold can be determined by combining statistical learning and engineering experience, and this embodiment does not impose a specific limitation. For example, after the weaving machine has been running for a period of time under normal and fault-free conditions, the average value and standard deviation of the historical resistance index of each track sector are automatically calculated. The alarm threshold can then be set as the average value + n × standard deviation (n is usually taken as 3 to 5).

[0083] It should be noted that the preset derating factor is a decimal between 0 and 1, and its specific value is linked to the mechanical safety margin of the wire. This embodiment does not impose a specific limitation. For example, the preset derating factor should be selected so that the tension after derating is in a lower range of the wire's safe stress range. For example, a preset derating factor of 0.7 means that the target tension will be reduced to 70% of the original target tension value in the high resistance area.

[0084] It should be noted that the specific value of the preset initial target tension is a core parameter directly given by the cable product process specification, and this embodiment does not impose a specific limitation. For example, when braiding 0.5mm medium-sized copper wire, the initial target tension value may be set between 5N and 15N.

[0085] It should be noted that if the target historical resistance index significantly exceeds the alarm threshold, such as exceeding the warning threshold by 2 times, the machine will be stopped immediately to prevent damage to the cable braiding machine.

[0086] A smart tension control device for a cable braiding machine includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of a smart tension control method for a cable braiding machine.

[0087] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0088] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for intelligent tension control of a cable braiding machine, characterized in that, The method includes: Initialization phase: During multiple consecutive spindle revolution cycles, the spindle revolution angle is divided to obtain multiple angle zones and corresponding angle zone numbers, and the load current is collected synchronously; the load currents belonging to the same angle zone number are processed to determine the reference load current corresponding to each angle zone number; the spindle revolution cycle refers to the time process during which the spindle revolves 360 degrees around the cable core. The process of calculating the spindle's revolution angle includes: Read the absolute position encoder signal of the spindle servo motor to obtain the current spindle angle value, and record it as the spindle angle; Multiply the spindle angle by the preset transmission ratio coefficient to obtain the cumulative rotation angle value of the spindle disk from the reference zero point; The cumulative rotation angle is calculated modulo 360 to obtain the spindle's revolution angle; The process of dividing the spindle's revolution angle yields multiple angle zones and corresponding zone numbers, including: The complete angular range of the spindle's revolution cycle is divided into a preset number of continuous angular intervals. Each angular interval is defined as an angular partition, and each angular partition is assigned a unique integer number in sequence as the angular partition number. Divide the spindle's revolution angle by 360 degrees, and multiply the quotient by the total number of angle partitions to obtain a real number result. Round the real number down to obtain the angle zone number corresponding to the spindle's revolution angle; Steady-state operation phase: Within each revolution cycle, the corresponding target angle zone number is determined based on the real-time spindle revolution angle; the net load torque is determined based on the target reference load current and real-time load current corresponding to the target angle zone number. Based on the real-time spindle revolution angle, the track sector and sector number to which it belongs are determined from multiple preset track sectors and their corresponding sector numbers; based on the change in the real-time spindle revolution angle, the net load torque corresponding to the same sector number is integrally calculated in the angular domain to determine the historical resistance index corresponding to the track sector. Based on the target reference load current, the servo motor outputs a feedforward compensation amount; if the difference between the real-time revolution angle and the starting revolution angle of the next track sector is less than the preset angle threshold, the target historical resistance index generated in the previous revolution cycle and corresponding to the next track sector is read; if the target historical resistance index exceeds the preset alarm threshold, tension adjustment is performed during the process of the spindle switching to the next track sector.

2. The intelligent tension control method for a cable braiding machine according to claim 1, characterized in that, The process of processing load currents belonging to the same corner zone number to determine the reference load current corresponding to each corner zone number includes: For each spindle revolution cycle, at each servo control moment within the spindle revolution cycle, the load current value is collected, and the angle zone number corresponding to the spindle revolution angle at the servo control moment is collected; wherein, the servo control moment is a constant fixed time interval shorter than the spindle revolution cycle. The load current value is accumulated into a temporary accumulation variable associated with the same corner zone number, and the sampling count of the corner zone number is incremented by one; After completing the data acquisition for multiple consecutive full revolution cycles, for each corner zone number, the corresponding temporary cumulative variable is divided by the number of samplings corresponding to the corner zone number to obtain the reference load current corresponding to the corner zone number. Store the reference load current corresponding to all corner zone numbers in the reference load current lookup set according to the corner zone number order.

3. The intelligent tension control method for a cable braiding machine according to claim 2, characterized in that, The process of determining the net load torque includes: For each servo control moment in each revolution cycle, the target angle zone number is calculated based on the real-time spindle revolution angle; From the lookup set of reference load currents, find the target reference load current that matches the target corner zone number; The net load torque is obtained by nonnegating the absolute difference between the real-time load current and the target reference load current.

4. The intelligent tension control method for a cable braiding machine according to claim 3, characterized in that, The process for determining the historical resistance index includes: Divide the real-time spindle revolution angle by 360 degrees, and multiply the quotient by the total number of preset track sectors to obtain the real value; perform a floor operation on the real value to obtain the sector number to which the real-time spindle revolution angle belongs; For each servo control moment in each revolution cycle, the spindle revolution angle collected at the previous servo control moment is obtained as a comparison spindle revolution angle. Calculate the algebraic difference between the real-time spindle revolution angle and the comparison spindle revolution angle; if the absolute value of the algebraic difference is greater than 180 degrees, subtract 360 degrees from the positive algebraic difference to obtain the final algebraic difference; add 360 degrees to the negative algebraic difference to obtain the final algebraic difference; if the absolute value of the algebraic difference is not greater than 180 degrees, directly use the algebraic difference; use the final algebraic difference as the revolution angle change at the moment of servo control; Multiply the change in revolution angle at each servo control moment by the net load torque to obtain the cumulative resistance characteristic value; based on the sector number to which the spindle revolution angle belongs, accumulate the absolute value of the calculated cumulative resistance characteristic value into an accumulation register dedicated to the same sector number. If a sector number change is detected, the final accumulated value in the accumulator register corresponding to the sector number before the change will be used as the historical resistance indicator corresponding to the sector number before the change; and the value of the accumulator register corresponding to the sector number before the change will be cleared to zero.

5. The intelligent tension control method for a cable braiding machine according to claim 1, characterized in that, The feedforward compensation amount output to the servo motor based on the target reference load current includes: Obtain the real-time current regulation calculated by the tension feedback controller; The sum of the target reference load current and the real-time current regulation is calculated as the final current regulation. The final current adjustment value is sent to the servo driver as the current command at the current moment.

6. The intelligent tension control method for a cable braiding machine according to claim 1, characterized in that, If the difference between the real-time orbital angle and the starting orbital angle of the next orbital sector is less than a preset angle threshold, the target historical resistance index corresponding to the next orbital sector generated in the previous orbital cycle is read, including: Increment the sector number to which the real-time spindle revolution angle belongs by one to obtain the target sector number of the next track sector. If the result of incrementing the sector number by one is equal to the total number of sectors, the target sector number is set to zero. Multiply the target sector number by the preset standard angle span of a single sector to obtain the starting angle value of the next track sector. Based on the difference between the starting angle value of the next track sector and the real-time spindle revolution angle, the angle difference is obtained; it is determined whether the angle difference is less than the preset angle threshold; if the angle difference is less than the preset angle threshold, the sector switching pre-read operation is triggered. In the previous complete orbital cycle, the target sector number is used as an index to find the data element corresponding to the index. The data element is the historical resistance index calculated and stored for the corresponding orbital sector. Use the identified historical resistance indicators as the target historical resistance indicators.

7. The intelligent tension control method for a cable braiding machine according to claim 6, characterized in that, If the target historical resistance index exceeds the preset alarm threshold, tension adjustment is performed during the spindle switching to the next track sector, including: If the target historical resistance index exceeds the preset alarm threshold, the preset original target tension value is multiplied by the preset reduction coefficient to obtain the target tension setting value; If the real-time spindle revolution angle is detected to reach or exceed the starting angle value of the next track sector for the first time, it is determined that the real-time spindle revolution angle has actually entered the next track sector, and the target input value of the tension controller is switched from the original target tension value to the target tension set value. If the real-time spindle revolution angle is detected to reach or exceed the termination angle value of the next track sector for the first time, it is determined that the spindle revolution angle has left the next track sector, and the target input value of the tension controller is switched from the target tension set value back to the original target tension value.

8. An intelligent tension control device for a cable braiding machine, characterized in that, The apparatus includes a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of the method as described in any one of claims 1 to 7.

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