A high-speed warp knitting machine power-off anti-collapse head control method and system

Abstract

The present application relates to the technical field of warp knitting machine, and particularly relates to a control method and system for power-off anti-collapse head of high-speed warp knitting machine, which comprises the following steps: S1: judging abnormal power-off event based on voltage drop and speed state; S2: issuing an emergency braking instruction immediately after confirming abnormal power-off; S3: monitoring the process of switching from the electric state to the regenerative power generation state of the main shaft, and evaluating the feedback energy for maintaining the voltage of the system DC bus; S4: collecting the speed feedback of each driven shaft, and evaluating the multi-shaft synchronization state; S5: calculating the regenerative energy fed back to the DC bus and the energy consumed by the system, and determining the surplus energy to be consumed; S6: dynamically controlling the power consumption of the auxiliary braking module; S7: determining whether the synchronous parking is successful; and S8: executing the safety locking logic and recording the key data after the parking is completed. According to the present application, a large-capacity backup power supply is not needed, and the internal energy of the system is fully utilized, so that the safe, reliable and low-cost multi-shaft synchronous parking control is realized.

Description

Technical Field

[0001] This invention relates to the field of warp knitting machine technology, and in particular to a method and system for controlling the head collapse prevention during power failure in high-speed warp knitting machines. Background Technology

[0002] When a warp knitting machine operates at high speed, the warp head must maintain strict synchronization with the main shaft to stably release the binding yarn for the knitting mechanism. If the warp head rotates too fast, the amount of yarn released exceeds the amount of yarn used, leading to yarn slack and excessive fabric weight. If the warp head rotates too slowly, the amount of yarn released is less than the amount of yarn used, resulting in excessively tight yarn or even breakage. When the equipment experiences an abnormal power outage, all servo motors enter a free-stop state. Due to the large rotational inertia of the main shaft (driving the knitting mechanism) and the small rotational inertia of the driven shafts (such as the warp head and chain), the driven shaft decelerates quickly under inertia, while the main shaft decelerates slowly. This causes the amount of yarn used to far exceed the amount of yarn released in a short period of time, resulting in the yarn being rapidly tightened until it breaks. This phenomenon is called "warp head breakage." After warp head breakage, hundreds to thousands of yarns need to be re-threaded, consuming a lot of manual time and seriously affecting production efficiency.

[0003] The existing technical solutions have obvious shortcomings:

[0004] 1. Traditional independent braking resistors for each axis cannot utilize energy, and high-power resistors are required for spindles with large inertia, resulting in high cost and large size;

[0005] 2. In the simple common DC bus scheme, the driver loses power after a power outage, the control logic fails, the system goes out of control, and multi-axis coordinated braking cannot be achieved;

[0006] 3. Equipping the entire main power supply circuit with an uninterruptible power supply (UPS) or backup power supply would be extremely costly and require a large amount of equipment.

[0007] Therefore, there is a need for a control method that can achieve safe, synchronous, and rapid stopping of multiple axes by utilizing the internal inertial kinetic energy of the system without relying on an external backup power source during abnormal power outages. Summary of the Invention

[0008] This invention provides a method and system for controlling the anti-breakage head of a high-speed warp knitting machine during power failure. In the event of an abnormal power failure, the system can quickly identify the power failure event, trigger emergency regenerative braking of the main shaft, use its feedback energy to maintain the bus voltage, coordinate multi-axis synchronous deceleration in real time, and dynamically manage braking energy to ultimately achieve synchronous stopping of all axes, thereby preventing yarn breakage.

[0009] This invention provides a method for controlling the head collapse prevention during power failure of a high-speed warp knitting machine, comprising the following steps:

[0010] S1: Real-time acquisition of system DC bus voltage and speed of each axis, and judgment of abnormal power outage events based on voltage drop and speed status;

[0011] S2: Upon confirmation of an abnormal power failure, immediately issue an emergency braking command with a preset maximum deceleration to the spindle drive;

[0012] S3: Monitor the process of the spindle switching from electric mode to regenerative power generation mode, and evaluate the effect of its feedback energy on maintaining the DC bus voltage of the system.

[0013] S4: Collect speed feedback from each driven axis, calculate its following error with the main axis speed, and evaluate the multi-axis synchronization status in real time;

[0014] S5: Based on the dynamic calculation of the regenerative energy fed back to the DC bus and the energy consumed by the system during the spindle braking process, determine the energy surplus to be consumed;

[0015] S6: Dynamically control the power consumption of the auxiliary braking module based on the energy surplus and DC bus voltage level;

[0016] S7: When all shaft speeds drop below the stop threshold and the synchronization error during the entire braking process meets the process requirements, the synchronous stop is considered successful.

[0017] S8: After parking is completed, execute the safety interlock logic, record key event data, and put the system into a safe standby state.

[0018] Furthermore, in step S1, determining the abnormal power outage event specifically involves:

[0019] The system collects the real-time DC bus voltage value of the main power supply circuit, as well as the working status signals and actual speeds of the main shaft and each driven shaft.

[0020] Determine if the bus voltage is lower than the rated threshold.

[0021] Determine whether the bus voltage change rate is continuously negative;

[0022] Determine if the operating status signal of at least one axis is unexpectedly lost and its rotational speed is higher than the operating threshold.

[0023] If all of the above conditions are met, then an abnormal power outage is determined to have occurred.

[0024] Furthermore, in step S2, the emergency braking command is specifically as follows:

[0025] Suspend all non-urgent periodic tasks and allocate all computing resources to executing the power outage emergency response sequence;

[0026] The system parameter table is used to retrieve the preset maximum emergency braking deceleration αmax of the spindle, the spindle moment of inertia with load Js is read, and the braking torque Tb=Js·αmax is calculated.

[0027] Apply braking torque Tb to the spindle to force it into an emergency deceleration process.

[0028] Furthermore, in step S3, the evaluation of the effect of its feedback energy on maintaining the DC bus voltage of the system specifically involves:

[0029] Continuously monitor the status feedback from the spindle drive to confirm that the spindle drive has switched from consuming electrical energy to generating power.

[0030] The DC bus voltage is then sampled at a higher frequency, and an evaluation time window Tw is set. The minimum value of the sampled DC bus voltage within this time window is checked to see if it is greater than the set minimum voltage threshold. If it is, the subsequent steps are executed. If not, the system records the fault and switches to the basic safety mode that does not rely on electrical control.

[0031] Furthermore, in step S4, the real-time evaluation of the multi-axis synchronization status specifically involves:

[0032] At regular intervals, obtain the actual rotational speed of the j-th driven shaft as ωsj; obtain the instantaneous rotational speed of the main shaft as ωa;

[0033] After acquiring the data, calculate the synchronization deviation Ds:

[0034] ;

[0035] Where N is the total number of driven shafts; ωra is the rated speed of the main shaft during normal operation; and kj is the weighting coefficient of the j-th driven shaft.

[0036] Furthermore, in step S5, the dynamic calculation of the required energy surplus is specifically as follows:

[0037] During spindle braking, the regenerative power Preg fed back to the DC bus is calculated in real time:

[0038] Preg = Tb·ωa·η;

[0039] Where ωa is the instantaneous rotational speed of the main spindle; η is the regenerative power generation efficiency of the electric spindle.

[0040] Integrate the estimated regenerative power to calculate the cumulative regenerative energy Ereg fed back by the spindle from braking start time t0 to the current time t. At the same time, estimate the total energy Econ consumed by all axes in the system from braking start to the current time t.

[0041] Calculate the estimated energy surplus on the DC bus at the current moment: Esur = Ereg - Econ.

[0042] Furthermore, in step S6, the power consumption of the dynamic control auxiliary braking module is specifically as follows:

[0043] Set the safe operating range of the bus voltage [Umin, Umax];

[0044] Calculate the reference power setting value Pb=Esur / △t for the auxiliary braking module;

[0045] Where Δt is the time constant of braking energy consumption;

[0046] Obtain the real-time DC bus voltage Udc, and control the final braking power Pfin based on the value of Udc:

[0047] If Udc > Umax, then the final braking power Pfin = min(Pb, Pmax), where Pmax is the set maximum braking power;

[0048] If Udc is within the safe operating range, then the final braking power Pfin = Pb + Kp·(Udc - Utar), where Kp is the voltage proportional adjustment coefficient and Utar is the target voltage value;

[0049] If Udc < Umin, then the final braking power Pfin = Pb·γ, where γ is the attenuation coefficient, which is taken as 0~1.

[0050] Furthermore, in step S7, determining that the synchronized parking was successful specifically involves:

[0051] Set a shaft speed stop threshold ωlow;

[0052] Set the maximum allowable synchronization deviation threshold Dsmax for the process;

[0053] Determine whether the absolute value of the rotational speed of all shafts is less than ωlow, and whether the historical maximum value of the synchronization deviation Ds calculated throughout the braking process does not exceed the maximum synchronization deviation threshold Dsmax; if both of the above conditions are met, the emergency stop due to power failure is determined to be a successful synchronization stop, otherwise it is recorded as an abnormal synchronization stop.

[0054] Furthermore, in step S8, the execution of the safety interlocking logic and the recording are specifically as follows:

[0055] If the synchronized parking is successful, proceed with the following steps:

[0056] Immediately issue a disable command to the servo drives of all axes;

[0057] Activate the mechanical safety lock of the key motion mechanism of the warp knitting machine;

[0058] Extract and store key data for this event from the controller cache, including the time of the abnormal power failure and various data acquired during the braking process;

[0059] If a synchronous stop fails, a fail-safe interlock is executed, and the abnormal data is recorded.

[0060] After recording is completed, the control system enters a low-power safe standby state, waiting for manual reset.

[0061] The present invention also provides a high-speed warp knitting machine power failure anti-collapse head control system, including a memory and a processor. The memory is used to store one or more program instructions; the processor is used to run one or more program instructions to execute the steps of the above-described high-speed warp knitting machine power failure anti-collapse head control method.

[0062] The technical solution of this invention can achieve the following technical effects:

[0063] This invention can identify abnormal power outages instantly and respond quickly using the residual power supply of the control system. It converts the massive inertial kinetic energy of the main shaft into electrical energy, feeding it back to the DC bus to form a temporary power grid, providing energy assurance for the controlled deceleration of the entire multi-axis system. Through real-time calculation and dynamic adjustment, it ensures that driven shafts such as the yarn head closely follow the main shaft's deceleration, maintaining stable yarn tension throughout the braking process and preventing yarn breakage (yarn head breakage) due to speed asynchrony. This method eliminates the need for a large-capacity backup power supply for the entire main circuit, fully utilizing the system's internal energy to achieve safe, reliable, and low-cost multi-axis synchronous parking control. Attached Figure Description

[0064] 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.

[0065] Figure 1 This is a flowchart illustrating the control method for preventing head collapse during power failure in high-speed warp knitting machines. Detailed Implementation

[0066] 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.

[0067] 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.

[0068] This invention relates to a method for controlling the anti-collapse of the warp knitting head on a high-speed warp knitting machine during power failure, comprising the following: Figure 1 The steps S1 to S8 shown constitute a closed-loop control system that integrates rapid abnormal event identification, emergency braking triggering, energy feedback utilization, multi-axis synchronous evaluation, and dynamic coordination. This ensures that even under extreme conditions of sudden external power outages, the warp knitting machine's axes can still achieve synchronized and rapid stopping under controlled conditions, thus preventing head collapse accidents. The specific details of each step are as follows:

[0069] S1: Real-time acquisition of system DC bus voltage and shaft speed, determining abnormal power outage events based on voltage dips and speed status. This step is the trigger switch for the entire emergency response mechanism, used to quickly and accurately distinguish between abnormal power outages and normal shutdowns.

[0070] S2: Upon confirmation of an abnormal power failure, immediately issue an emergency braking command at the preset maximum deceleration to the spindle drive. The spindle is the component with the largest inertia in the system and the main storage unit of kinetic energy. The core of this step is to command the spindle to decelerate at the maximum safe deceleration allowed by the system, so as to quickly release its huge inertial kinetic energy.

[0071] S3: Monitor the process of the spindle switching from electric to regenerative braking and evaluate the effect of its feedback energy on maintaining the DC bus voltage. During emergency braking and deceleration, since the external power is cut off, the spindle continues to rotate under the influence of its huge inertial kinetic energy. The spindle motor will switch from an electric state that consumes electrical energy to a regenerative braking state that feeds electrical energy back to the DC bus. The inertial kinetic energy will be converted into electrical energy to supply the system for subsequent processing. Theoretically, the optimal result is to use this energy until the braking ends. This step is used to verify whether this feedback energy can effectively support the bus voltage.

[0072] S4: Collect speed feedback from each driven shaft, calculate its following error relative to the main shaft speed, and evaluate the multi-axis synchronization status in real time. Driven shafts such as the headstock and chain must closely follow the main shaft deceleration to maintain yarn tension. This step defines a comprehensive synchronization deviation index to quantitatively and in real time monitor the synchronization performance between the driving and driven shafts throughout the braking process.

[0073] S5: Based on the dynamic calculation of the regenerative energy fed back to the DC bus and the energy consumed by the system during the spindle braking process, determine the required energy surplus. Since the energy required by the control circuit is relatively small, the energy fed back by the spindle often has a surplus after maintaining the operation of the system control circuit and the driven shaft. This step is mainly used to calculate the approximate amount of surplus energy.

[0074] S6: Dynamically control the power consumption of the auxiliary braking module based on the energy surplus and DC bus voltage level. The auxiliary braking module (usually a braking resistor) safely dissipates excess energy, preventing damage to equipment due to excessive bus voltage. This step dynamically adjusts the braking power based on the calculated energy surplus and real-time voltage to achieve stable voltage control.

[0075] S7: When all shaft speeds drop below the stopping threshold and the synchronization error throughout the braking process meets the process requirements, the synchronous stop is considered successful. This step is the final evaluation of the entire emergency braking process and requires rigorous verification from two dimensions: "whether it has come to a complete stop" and "whether the stopping process is synchronized".

[0076] S8: After stopping, execute safety interlock logic (such as locking each axis to prevent accidental movement), record key event data, and put the system into a safe standby state. The data is used for fault analysis and process optimization.

[0077] In the preferred step S1, determining the abnormal power outage event specifically involves:

[0078] S1.1: During normal system operation, the real-time DC bus voltage value Udc of the main power supply circuit of the system is continuously collected through the voltage detection module, and the working status signals and actual speed of the main shaft and each driven shaft are also collected.

[0079] S1.2: Set three criteria that must be met simultaneously to distinguish it from normal shutdown or fluctuation:

[0080] Criterion A (Voltage Dip Criterion): Determines whether the bus voltage is lower than the rated threshold, i.e., Udc < UN·b, where UN is the rated DC bus voltage of the system (e.g., 537V), and b is the voltage dip coefficient, which is set according to the system tolerance and is usually taken as 0.85~0.95. This criterion captures the absolute value of voltage dips.

[0081] Criterion B (Voltage Change Trend Criterion): Determine whether the bus voltage change rate is continuously negative. Specifically, calculate the bus voltage change rate dUdc / dt, where t is time, and determine whether it is continuously negative for more than a short-term threshold (e.g., 10ms). This criterion is used to identify the irreversible downward trend of voltage and avoid instantaneous interference that may trigger the braking process.

[0082] Criterion C (Axis Status Abnormality Criterion): Determine whether at least one axis's working status signal is unexpectedly lost (i.e., the working status signal should originally be rotation, but due to power failure, the component that feeds back the working status signal of the axis no longer works, so the working status signal will be lost) and its speed is higher than the operating threshold. This criterion combines the fact that the control command is lost and the machine is still running at high speed, and is the key to determining that it is an abnormal power failure rather than a normal stop.

[0083] S1.3: When criteria A, B, and C are all determined to be true within the same control cycle, the system finally confirms that an "abnormal power failure" event has occurred and immediately triggers the emergency braking sequence in step S2.

[0084] Preferably, in step S2, the emergency braking command is specifically as follows:

[0085] S2.1: After receiving the abnormal power failure confirmation signal from step S1, the main controller immediately raises the interrupt priority, suspends all non-emergency periodic tasks related to process production (such as warp knitting related calculations, human-machine interface refresh, etc.), and uses all computing resources to execute the power failure emergency response sequence.

[0086] S2.2: From the system's pre-stored safety parameter table, retrieve the preset maximum emergency braking deceleration αmax of the main shaft. This value needs to be determined during equipment debugging based on factors such as mechanical strength and yarn tension tolerance limits to ensure that the braking process is both fast and safe. Simultaneously, read the rotational inertia Js of the main shaft with load. The magnitude of the rotational inertia Js is related to the load on the motor rotor, main shaft, and weaving mechanism. However, since the load on the motor rotor, main shaft, and weaving mechanism remains almost constant in each warp knitting process, the rotational inertia Js is a constant value for each warp knitting operation. Calculate the theoretical braking torque Tb = Js·αmax to be applied to the main shaft.

[0087] S2.3: The calculated braking torque Tb is immediately sent to the spindle servo driver. After receiving the command, the driver controls the motor to output the corresponding braking torque, thus forcing the spindle into an emergency deceleration process targeting αmax.

[0088] Preferably, in step S3, the evaluation of the effect of its feedback energy on maintaining the DC bus voltage of the system specifically includes:

[0089] S3.1: While the spindle is performing emergency braking, continuously monitor the status feedback from the spindle drive, focusing on the bits that represent the operating status. When the status indication is detected to change from "electric operation" (usually corresponding to speed or torque control mode) to "regenerative power generation" (or "energy feedback"), it is confirmed that the physical process has changed and that the spindle drive has changed from consuming electrical energy to generating electricity. In the generating state, the spindle relies on its large inertia to rotate, driving the rotor in the motor to rotate and cut the magnetic field lines of the motor to generate electrical energy.

[0090] S3.2: After confirming that the spindle drive has entered the generator state, sample the DC bus voltage Udc at a higher frequency to obtain more refined voltage fluctuation information.

[0091] S3.3: Set a short evaluation time window Tw (e.g., 50ms). Within this window, continuously collect the instantaneous value of Udc and find its minimum value.

[0092] Check if the minimum value of the sampled DC bus voltage is greater than the set minimum voltage threshold; if so, it means that the electrical energy fed back by the spindle has successfully withstood the downward trend of the bus voltage, and the system is able to maintain operation for a short time after a power outage by relying on its own kinetic energy, then continue to execute the subsequent steps.

[0093] If not, the assessment indicates a voltage support failure, meaning insufficient feedback energy or a slow response. In this case, the system will immediately record a "voltage collapse" fault code and abandon the precision synchronization strategy based on electrical control. Instead, it will forcibly switch to a basic safety mode that does not rely on electrical control. The basic safety mode will directly issue commands to shut down each drive and trigger the independent mechanical brakes or friction brakes of each axis to stop the vehicle in the most direct way, but it cannot guarantee synchronization.

[0094] Preferably, in step S4, the real-time evaluation of the multi-axis synchronization status specifically involves:

[0095] This step is executed cyclically with a fixed short control cycle (e.g., 10ms).

[0096] S4.1: At the beginning of each cycle, obtain the actual rotational speed of the j-th driven shaft as ωsj; obtain the instantaneous rotational speed of the main shaft as ωa.

[0097] S4.2: To comprehensively quantify the overall following error between all driven axes and the master axis, a dimensionless comprehensive index, synchronization deviation Ds, is defined, and its calculation formula is as follows:

[0098] ;

[0099] Where N is the total number of driven axes;

[0100] ωra is the rated speed of the main spindle during normal operation. ωra is introduced to normalize the speed difference, so that the synchronization deviation Ds at different operating speeds are comparable.

[0101] kj is the weighting coefficient of the j-th driven shaft. This coefficient is determined by the specific textile process and yarn tension relationship, and is used to characterize the importance of the driven shaft synchronizing with the main shaft.

[0102] The smaller the synchronization deviation Ds value, the smaller the weighted relative deviation between the speeds of all driven axes and the speed of the master axis, indicating better multi-axis synchronization performance; the larger the value, the more severe the loss of synchronization. The calculated real-time Ds value will be continuously cached and used as a key process variable, directly used in the subsequent step S7 to determine whether the braking process is successfully synchronized.

[0103] Preferably, in step S5, the dynamic calculation of the required energy surplus is specifically as follows:

[0104] S5.1: During spindle braking, the regenerative power Preg fed back to the DC bus is calculated in real time.

[0105] Preg = Tb·ωa·η;

[0106] Where ωa is the instantaneous rotational speed of the main shaft;

[0107] η is the regenerative power generation efficiency of the electric spindle, which is an empirical coefficient less than 1 (usually 0.8~0.9) used to account for copper loss, iron loss, switching loss, etc.

[0108] S5.2: Integrate the estimated regenerative power to calculate the cumulative regenerative energy Ereg fed back by the main shaft from braking start time t0 to the current time t;

[0109] Simultaneously, estimate the total energy Econ consumed by all axes in the system from the start of braking to the current time t. This mainly includes: the standby power consumption of the control loop (PLC, driver control circuit), the operation of the driven axis motor (which may be in a state of slight power generation or consumption), and system line losses. An average standby power can be used for a simplified estimate.

[0110] S5.3: Calculate the estimated energy surplus on the DC bus at the current moment: Esur = Ereg - Econ. This value is the core basis for determining whether the auxiliary braking module needs to be activated and for determining its braking power. If Esur > 0, it means there is surplus energy that needs to be dissipated; if Esur < 0, it means that the feedback energy is only sufficient or insufficient to maintain the system's consumption.

[0111] Preferably, in step S6, the power consumption of the dynamically controlled auxiliary braking module is specifically as follows:

[0112] S6.1: Obtain the real-time estimated energy surplus Esur calculated in step S5, and the real-time DC bus voltage Udc collected by the voltage detection module; set the safe operating range of the bus voltage [Umin, Umax].

[0113] S6.2: Calculate the reference power setting value Pb=Esur / △t for the auxiliary braking module based on the energy surplus Esur;

[0114] Wherein, Δt is the time constant of braking energy consumption, which can be set according to the total inertia of the system and the desired voltage regulation speed.

[0115] The physical meaning of this formula is: the plan is to consume the current surplus energy Esur on an average basis within the future time Δt, which requires the auxiliary braking module to achieve the required operating power.

[0116] S6.3: Perform closed-loop correction based on Udc feedback to determine the final braking power Pfin:

[0117] Case A (Overvoltage Risk): If Udc > Umax, it means that the voltage has exceeded the limit and full braking is required immediately. Then the final braking power Pfin = min(Pb, Pmax), where Pmax is the set maximum braking power.

[0118] Scenario B (Normal Voltage): If Udc is within the safe operating range, proportional regulation is used to stabilize the voltage. The final braking power Pfin = Pb + Kp·(Udc - Utar), where Kp is the voltage proportional regulation coefficient and Utar is the target voltage value (usually the midpoint between Umin and Umax). This formula increases braking power when the voltage is higher than the target value and decreases braking power when the voltage is lower than the target value.

[0119] Scenario C (Undervoltage Risk): If Udc < Umin, it indicates a risk of insufficient voltage in the control system. Braking power consumption should be reduced to prioritize power supply to the control system. The final braking power Pfin = Pb·γ, where γ is the attenuation coefficient, ranging from 0 to 1. In this case, by drastically reducing braking power consumption, the bus voltage can be restored.

[0120] Preferably, in step S7, determining that the synchronous parking was successful specifically involves:

[0121] S7.1: Set the threshold parameters required for the decision criteria:

[0122] Set a shaft speed stop threshold ωlow. The value of ωlow is extremely small (e.g., 0.1 rad / s) to determine whether the mechanical shaft has basically stopped rotating. This value needs to be greater than the encoder measurement noise, but much lower than the operating speed.

[0123] Set the maximum allowable synchronization deviation threshold Dsmax, which is the limit value set according to the yarn tension process requirements; if the synchronization error during braking exceeds this value, it is considered that there is a risk of yarn breakage and the stopping process is unqualified.

[0124] S7.2: Continuously monitor the real-time speed of all shafts, determine whether the absolute value of the rotational speed of all shafts is less than ωlow, and whether the historical maximum value of the synchronization deviation Ds calculated during the entire braking process does not exceed the maximum synchronization deviation threshold Dsmax; if both of the above conditions are met, determine that the emergency stop due to power failure is a successful synchronization stop, otherwise record it as an abnormal synchronization stop.

[0125] Preferably, in step S8, the execution of the safety interlocking logic and recording specifically involves:

[0126] Receive the final determination result from step S7 (synchronous parking successful or synchronous parking abnormal).

[0127] If the synchronized parking is successful, proceed with the following steps:

[0128] Immediately issue a disable command to the servo drives of all axes to ensure that all motor output axes are in a free or zero torque state, preventing residual control signals from causing unexpected actions;

[0129] Activate the mechanical safety locks of the key motion mechanisms of the warp knitting machine (especially the main shaft and the head shaft) to physically lock the shafts and prevent positional displacement caused by external forces or vibrations;

[0130] Extract and store key data for this event from the controller cache, including the moment of the abnormal power outage and various data acquired during the braking process.

[0131] If a synchronous stop is abnormal, a fail-safe interlock will be executed. The procedure is as follows: while executing the above-mentioned electrical and mechanical interlocks, additional detailed abnormal data will be recorded, such as the time and amplitude when DS first exceeds the limit, the time difference between the first stopped shaft and the last stopped shaft, etc., to provide a basis for subsequent root cause analysis of the fault.

[0132] After completing all interlocking and recording operations, the main control system switches from "emergency handling" mode to "safe standby" mode. In this mode, only minimal status monitoring and communication functions are maintained (such as waiting for the host computer to query fault records), energy consumption is reduced to a minimum, and the system waits for operators to arrive to perform subsequent processing such as resetting and threading.

[0133] This invention also relates to a high-speed warp knitting machine power failure prevention and head collapse control system, comprising a DC bus servo system hardware platform. This platform mainly includes: a control loop (including a PLC and UPS), a main power supply loop with a voltage detection module, and a DC bus system (including a servo power supply, spindle driver, driven spindle driver, and braking module). In the event of an abnormal power failure, the UPS provides continuous power to the control loop, ensuring the normal operation of the control logic. The system also includes a memory and a processor. The memory stores one or more program instructions; the processor executes one or more program instructions to perform the steps of the aforementioned high-speed warp knitting machine power failure prevention and head collapse control method.

[0134] 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 control method for a high-speed warp knitting machine power-off crash head, characterized by the steps of include: S1: Real-time acquisition of system DC bus voltage and speed of each axis, and judgment of abnormal power outage events based on voltage drop and speed status; S2: Upon confirmation of an abnormal power failure, immediately issue an emergency braking command with a preset maximum deceleration to the spindle drive; S3: Monitor the process of the spindle switching from electric mode to regenerative power generation mode, and evaluate the effect of its feedback energy on maintaining the DC bus voltage of the system. S4: Collect speed feedback from each driven axis, calculate its following error with the main axis speed, and evaluate the multi-axis synchronization status in real time; S5: Based on the dynamic calculation of the regenerative energy fed back to the DC bus and the energy consumed by the system during the spindle braking process, determine the energy surplus to be consumed; S6: Dynamically control the power consumption of the auxiliary braking module based on the energy surplus and DC bus voltage level; S7: When all shaft speeds drop below the stop threshold and the synchronization error during the entire braking process meets the process requirements, the synchronous stop is considered successful. S8: After parking is completed, execute the safety interlock logic, record key event data, and put the system into a safe standby state; Specifically, in step S2, the emergency braking command is as follows: Suspend all non-urgent periodic tasks and allocate all computing resources to executing the power outage emergency response sequence; The system parameter table is used to retrieve the preset maximum emergency braking deceleration αmax of the spindle, the spindle moment of inertia with load Js is read, and the braking torque Tb=Js·αmax is calculated. Apply braking torque Tb to the spindle to force it into an emergency deceleration process; In step S5, the dynamic calculation of the required energy surplus is as follows: During spindle braking, the regenerative power Preg fed back to the DC bus is calculated in real time: Preg = Tb·ωa·η; Where ωa is the instantaneous rotational speed of the main spindle; η is the regenerative power generation efficiency of the electric spindle. Integrate the estimated regenerative power to calculate the cumulative regenerative energy Ereg fed back by the spindle from braking start time t0 to the current time t. At the same time, estimate the total energy Econ consumed by all axes in the system from braking start to the current time t. Calculate the estimated energy surplus on the DC bus at the current moment: Esur = Ereg - Econ.

2. The high speed warp knitting machine power-off crash head control method according to claim 1, characterized in that, In step S1, determining the abnormal power outage event specifically involves: The system collects the real-time DC bus voltage value of the main power supply circuit, as well as the working status signals and actual speeds of the main shaft and each driven shaft. Determine if the bus voltage is lower than the rated threshold. Determine whether the bus voltage change rate is continuously negative; Determine if the operating status signal of at least one axis is unexpectedly lost and its rotational speed is higher than the operating threshold. If all of the above conditions are met, then an abnormal power outage is determined to have occurred.

3. The high speed warp knitting machine power-off crash head control method according to claim 1, characterized in that, In step S3, the evaluation of the feedback energy's effect on maintaining the system's DC bus voltage specifically involves: Continuously monitor the status feedback from the spindle drive to confirm that the spindle drive has switched from consuming electrical energy to generating power. The DC bus voltage is then sampled at a higher frequency, and an evaluation time window Tw is set. The minimum value of the sampled DC bus voltage within this time window is checked to see if it is greater than the set minimum voltage threshold. If it is, the subsequent steps are executed. If not, the system records the fault and switches to the basic safety mode that does not rely on electrical control.

4. The high-speed warp knitting machine power failure anti-collision head control method according to claim 1, characterized in that, In step S4, the real-time evaluation of the multi-axis synchronization status specifically involves: At regular intervals, obtain the actual rotational speed of the j-th driven shaft as ωsj; obtain the instantaneous rotational speed of the main shaft as ωa; After acquiring the data, calculate the synchronization deviation Ds: ； Where N is the total number of driven shafts; ωra is the rated speed of the main shaft during normal operation; and kj is the weighting coefficient of the j-th driven shaft.

5. The high-speed warp knitting machine power failure anti-collision head control method according to claim 1, characterized in that, In step S6, the power consumption of the dynamic control auxiliary braking module is specifically as follows: Set the safe operating range of the bus voltage [Umin, Umax]; Calculate the reference power setting value Pb=Esur / △t for the auxiliary braking module; Where Δt is the time constant of braking energy consumption; Obtain the real-time DC bus voltage Udc, and control the final braking power Pfin based on the value of Udc: If Udc > Umax, then the final braking power Pfin = min(Pb, Pmax), where Pmax is the set maximum braking power; If Udc is within the safe operating range, then the final braking power Pfin = Pb + Kp·(Udc - Utar), where Kp is the voltage proportional adjustment coefficient and Utar is the target voltage value; If Udc < Umin, then the final braking power Pfin = Pb·γ, where γ is the attenuation coefficient, which is taken as 0~1.

6. The high-speed warp knitting machine power failure anti-collision head control method according to claim 4, characterized in that, In step S7, determining that the synchronized parking was successful specifically involves: Set a shaft speed stop threshold ωlow; Set the maximum allowable synchronization deviation threshold Dsmax for the process; Determine whether the absolute value of the rotational speed of all shafts is less than ωlow, and whether the historical maximum value of the synchronization deviation Ds calculated throughout the braking process does not exceed the maximum synchronization deviation threshold Dsmax; if both of the above conditions are met, the emergency stop due to power failure is determined to be a successful synchronization stop, otherwise it is recorded as an abnormal synchronization stop.

7. The high-speed warp knitting machine power failure anti-collision head control method according to claim 6, characterized in that, In step S8, the execution of the safety interlocking logic and the recording are specifically as follows: If the synchronized parking is successful, proceed with the following steps: Immediately issue a disable command to the servo drives of all axes; Activate the mechanical safety lock of the key motion mechanism of the warp knitting machine; Extract and store key data for this event from the controller cache, including the time of the abnormal power failure and various data acquired during the braking process; If a synchronous stop fails, a fail-safe interlock is executed, and the abnormal data is recorded. After recording is completed, the control system enters a low-power safe standby state, waiting for manual reset.

8. A high-speed warp knitting machine power failure anti-collision head control system, characterized in that, It 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 for performing the steps of the high-speed warp knitting machine power failure anti-collapse head control method as described in any one of claims 1 to 7.

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