Servo motor position control method for a lifting mechanism of a ring spinning machine

Abstract

The application discloses a servo motor position control method of a lifting mechanism of a ring spinning frame, and relates to the field of motor control of the ring spinning frame. The method comprises the following steps: acquiring the current height position, load weight and installation inclination angle of the lifting mechanism; determining speed control information and a to-position tolerance bandwidth according to a lifting instruction; correcting a theoretical position deviation; calculating a compensation torque of the servo motor according to total resistance; determining an axial elastic compression amount and an angle compensation amount of the corrected position deviation, so as to determine a target rotation angle; generating motion trajectory information according to the target rotation angle and the speed control information; controlling the position of the servo motor by using the motion trajectory information; and converting the compensation torque into a feedforward current instruction to perform feedforward control on the servo motor. The application controls the position of the motor by correcting the position deviation, compensating the torque, compensating the elastic angle, planning the trajectory and performing the feedforward control, and controls the position of the motor in combination with a process stage, so that the lifting mechanism is lifted with high precision, high speed and high stability in the whole spinning cycle.

Description

Technical Field

[0001] This invention relates to the field of ring spinning machine motor control, and more specifically, to a servo motor position control method for the lifting mechanism of a ring spinning machine. Background Technology

[0002] Ring spinning frames are widely used yarn production equipment in the textile industry. One of their core components is the ring rail lifting mechanism, used to support and position the bobbin's height during the spinning process. Traditional ring spinning frames often use manual adjustment or simple open-loop motor control for lifting operations. This method suffers from low positioning accuracy, slow response speed, sensitivity to load changes, and poor adaptability to spinning processes. In actual production, as the bobbin gradually increases in weight from empty to full, the load on the ring rail constantly changes. Traditional control methods struggle to compensate for pitch errors, friction, and mechanical elastic deformation in the screw drive system in real time, leading to lag, vibration, or even overshoot in the ring rail lifting, affecting spinning quality and production efficiency.

[0003] While some related technologies employ servo motors to drive screw lifting, most solutions only address mechanical structure improvements or simple closed-loop position control, failing to consider complex factors such as cumulative screw pitch error, dynamic load variations, process stage differences, and screw elastic deformation. Furthermore, trajectory planning and feedforward torque compensation lack comprehensive strategies integrated with actual spinning processes and load characteristics, making it difficult to maintain high-precision, rapid-response, and stable lifting control throughout the entire spinning cycle.

[0004] In view of the above-mentioned technological status, there is an urgent need for a servo motor position control method that can combine the spinning process stages, screw drive characteristics and dynamic load changes. Summary of the Invention

[0005] The purpose of this invention is to provide a servo motor position control method for the lifting mechanism of a ring spinning machine, aiming to solve at least one problem existing in the prior art.

[0006] The technical solution of the present invention is: a servo motor position control method for the lifting mechanism of a ring spinning frame, the method comprising the following steps: Obtain the current height position, load weight, and mechanical installation tilt angle of the ring spinning machine lifting mechanism; In response to a lifting command, speed control information and positioning tolerance band width are determined based on the lifting command, wherein the lifting command includes at least a target height value and a process stage identifier; The theoretical position deviation is calculated based on the current height position and the target height value, and the theoretical position deviation is corrected to obtain the corrected position deviation; The total resistance is determined based on the load weight and the mechanical mounting angle, and the compensation torque of the servo motor is calculated based on the total resistance. The axial elastic compression of the lifting mechanism is calculated based on the load weight. The first angle compensation amount corresponding to the axial elastic compression amount and the second angle compensation amount corresponding to the corrected position deviation are determined. The target rotation angle is determined based on the first angle compensation amount and the second angle compensation amount. Motion trajectory information is generated based on the target rotation angle and the speed control information; The motion trajectory information is used to control the position of the servo motor of the lifting mechanism, and the compensation torque is converted into a feedforward current command to perform feedforward control on the servo motor.

[0007] In some embodiments of the present invention, the step of correcting the theoretical position deviation to obtain the corrected position deviation includes: Based on the current height position, query the pre-stored pitch error compensation table to obtain the pitch ratio coefficient corresponding to the height segment where the current height position is located; The product of the theoretical position deviation and the pitch ratio coefficient is determined as the corrected position deviation; wherein, the pitch ratio coefficient is the ratio of the measured pitch value of the screw in the lifting mechanism in the corresponding height section to the nominal pitch value.

[0008] In some embodiments of the present invention, determining the total resistance based on the load weight and the mechanical mounting angle includes: Calculate the axial component of gravity along the screw based on the load weight and the mechanical installation tilt angle; The lubrication condition attenuation coefficient is determined based on the cumulative value of the screw running time, and the dynamic friction force is determined based on the lubrication condition attenuation coefficient. The total resistance is obtained by summing the component of gravity along the screw axis and the dynamic friction force.

[0009] In some embodiments of the present invention, determining the first angle compensation amount corresponding to the axial elastic compression amount includes: The stiffness coefficient is determined by a pre-constructed elastic deformation calculation model, and the first angle compensation amount corresponding to the elastic compression amount is calculated by the stiffness coefficient. The elastic deformation calculation model represents the functional relationship between the stiffness coefficient of the lifting mechanism, the load weight and the axial deformation.

[0010] In some embodiments of the present invention, the motion trajectory information includes at least acceleration phase information, constant speed phase information, and deceleration phase information, and the step of generating motion trajectory information based on the target rotation angle and the speed control information includes: Obtain the actual torque output value and angular acceleration value during the historical lifting process; The total inertia parameter is updated by the ratio of the actual torque output value to the angular acceleration value; The updated total inertia parameter is compared with the rated torque of the servo motor to obtain the maximum allowable acceleration value under the current operating conditions; The acceleration phase information is determined based on the maximum acceleration value, and the deceleration phase information is calculated based on the position tolerance band width. The acceleration phase information includes at least acceleration, and the deceleration phase information includes at least the starting position of the deceleration segment and the deceleration segment acceleration. Based on the determined acceleration phase information and deceleration phase start position, the constant speed phase information is planned and generated.

[0011] In some embodiments of the present invention, the servo motor includes a position loop and a speed loop, the lifting mechanism is equipped with a rotary encoder, and the step of controlling the position of the servo motor of the lifting mechanism using the motion trajectory information includes: A position command sequence is generated based on the motion trajectory, and the tracking error is calculated by combining the motor angle fed back in real time by the rotary encoder. The proportional gain of the position loop is adjusted according to the tracking error. When the tracking error is greater than the width of the position tolerance band, the proportional gain is adjusted to a first gain value. When the tracking error falls within the width of the position tolerance band, the proportional gain is adjusted to a second gain value, wherein the first gain value is greater than the second gain value.

[0012] In some embodiments of the present invention, converting the compensated torque into a feedforward current command for feedforward control of the servo motor includes: During the acceleration phase, a first feedforward current is calculated based on the maximum acceleration value and the total inertia parameter and then superimposed on the drive current of the servo motor. During the constant speed phase, a second feedforward current is calculated based on the total resistance and superimposed on the drive current of the servo motor, wherein the second feedforward current is less than the first feedforward current.

[0013] In some embodiments of the present invention, the method further includes: When the motor angle enters the positioning tolerance zone corresponding to the target rotation angle, and the speed of the lifting mechanism is lower than the crawling speed threshold and continues to exceed the judgment time, a positioning completion signal is output.

[0014] In some embodiments of the present invention, the process stage identifier includes a small yarn stage, a medium yarn stage, and a large yarn stage, and the step of determining the speed control information and the positioning tolerance band width based on the lifting command includes: When the process stage is identified as the small yarn stage, the width of the arrival tolerance band is determined as the first width; When the process stage is identified as the medium yarn stage or the large yarn stage, the width of the positioning tolerance band is determined as the second width, wherein the first width is smaller than the second width.

[0015] In some embodiments of the present invention, the method further includes: Obtain the current temperature information of the screw in the lifting mechanism; Based on the difference between the current temperature and the preset reference temperature, and in conjunction with the thermal expansion coefficient and length of the screw, the thermal elongation of the screw is calculated. The thermal elongation is converted into a third angle compensation amount and added to the target rotation angle.

[0016] This invention achieves high-precision, rapid, and stable lifting of the lifting mechanism throughout the entire spinning cycle by correcting position deviations, compensating for torque, compensating for elastic angles, trajectory planning, and feedforward control, combined with a motor position control method based on spinning process stage parameters, thereby improving spinning quality and production efficiency. Attached Figure Description

[0017] Figure 1 This is a flowchart of the steps of the servo motor position control method for the lifting mechanism of the ring spinning machine provided in the embodiment of the present invention; Figure 2 This is a schematic diagram of the servo motor position control system of the lifting mechanism of the ring spinning machine provided in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Reference Figure 1 This invention illustrates a servo motor position control method for the lifting mechanism of a ring spinning machine provided in an embodiment of the present invention.

[0020] This method may specifically include the following steps: Step 101: Obtain the current height position, load weight, and mechanical installation tilt angle of the ring spinning machine lifting mechanism.

[0021] A ring spinning frame is a textile machine that twists roving and winds it into a fine yarn bobbin. The lifting mechanism, specifically the ring rail lifting mechanism, is the core component of the ring spinning frame. The ring rail lifting mechanism supports the ring rail and guides the yarn bobbin to move vertically up and down during spinning, causing the yarn to wind around the bobbin surface in a predetermined shape. The ring spinning frame lifting mechanism includes a screw, nut, ring rail, and auxiliary connecting parts. The current height position refers to the real-time spatial position of the lifting mechanism in the vertical direction. The load weight refers to the total mass carried by the lifting mechanism, which includes the weight of the ring rail, the weight of the yarn bobbin, and the weight of the yarn. The mechanical installation tilt angle refers to the installation skew angle of the lifting mechanism relative to the vertical plane.

[0022] In a specific implementation of this invention, an incremental rotary encoder installed at the fixed end of the lifting mechanism acquires the current rotation angle of the servo motor. Specifically, a 2500-line incremental rotary encoder is fixedly installed on the tail end cover of the servo motor, and the encoder shaft is coaxially connected to the motor shaft via a rigid coupling. The rotation angle of the servo motor is acquired in real time, and then the acquired rotation angle is converted into the current height position of the ring rail. Simultaneously, the load weight detected by the weighing sensor is read. The load weight includes the weight of the ring rail itself, the weight of the yarn tube, and the weight of the yarn. The mechanical installation tilt angle of the lifting mechanism is measured by an tilt sensor. These three parameters together constitute the initial state parameters of the lifting mechanism.

[0023] When the ring spinning machine is started, the present invention reads the motor angle as 1800° by a 2500-line incremental rotary encoder installed on the spinning machine, which is converted into the current height position of the lifting mechanism as 72mm. The present invention detects the load weight by a weighing sensor, including the weight of the ring rail itself (8kg) and the total weight of the empty yarn tube (12kg), that is, the load weight is 20kg. The tilt angle of the lifting mechanism is measured as 2° by a tilt sensor. The combination of these three parameters forms the initial state parameter set [72mm, 20kg, 2°], which is used for subsequent steps.

[0024] This invention provides complete initial state parameters for subsequent position control by acquiring the current height position, load weight, and mechanical installation tilt angle. This enables the control method to adaptively adjust the control strategy according to the actual load conditions and mechanical installation status, avoiding position errors caused by load changes or installation deviations, and improving the positioning accuracy and adaptability of the lifting mechanism.

[0025] Step 102: In response to the lifting command, determine the speed control information and the positioning tolerance band width based on the lifting command. The lifting command includes at least the target height value and the process stage identifier.

[0026] Among them, the lifting command refers to the motion command issued by the spinning machine main control system to the servo controller, which carries at least the target height value and the process stage identifier; the target height value is the expected position value that the ring rail needs to reach; the process stage identifier is used to distinguish different periods in the entire spinning process, including the small yarn stage, the medium yarn stage, and the large yarn stage; the speed control information is the constraint parameter used to guide the change of the servo motor lifting speed, including the lifting speed curve template; the position tolerance band width is used to determine the allowable position error range for lifting to reach the target position, and exceeding this range is considered as not reaching the target position.

[0027] In a specific implementation of this invention, a lifting target command is received from the spinning machine's main control system, and the target height value and spinning process stage identifier are parsed from the command. Based on the parsed process stage identifier, a pre-stored process parameter library is queried to extract the lifting speed curve template and the position tolerance band width corresponding to that process stage identifier. The lifting speed curve template defines the maximum allowable lifting speed and acceleration constraint range corresponding to different spinning stages, and the position tolerance band width is used for subsequent position deviation determination and gain adjustment.

[0028] Taking the ring spinning machine in step 101 as an example, the main control system issues a lifting command with a target height of 150mm, and the process stage is identified as the large yarn stage. After parsing the command, the servo controller queries the process parameter library based on the large yarn stage identifier to extract the upper limit of the lifting speed (50mm / s) and the tolerance band width (±0.3mm) corresponding to the large yarn stage. The lifting speed curve template specifies that the acceleration during the acceleration phase should not exceed 1800° / s. 2 During the constant velocity phase, the maximum speed is 1800° / s, and during the deceleration phase, the deceleration does not exceed -1500° / s. 2 .

[0029] In some embodiments of the present invention, the process stage identifiers include the small yarn stage, the medium yarn stage, and the large yarn stage. Step 102, "determining the speed control information and the positioning tolerance band width based on the lifting command," may specifically include the following sub-steps: Sub-step 1021: When the process stage is identified as the small yarn stage, the width of the arrival tolerance band is determined as the first width; Sub-step 1022: When the process stage is identified as the medium yarn stage or the large yarn stage, the width of the arrival tolerance band is determined as the second width, wherein the first width is smaller than the second width.

[0030] Taking the ring spinning machine in steps 101 and 102 as an example, the servo controller parses the lifting command to obtain the process stage identifier. If the process stage identifier is the small yarn stage, the yarn tube is in an empty tube state, and the yarn begins to wind. The positioning accuracy requirement for the ring rail lifting is the highest, and the width of the positioning tolerance zone is determined to be the first width ±0.15mm. If the process stage identifier is the medium yarn stage or the large yarn stage, the yarn tube has already wound part of the yarn or is close to full yarn. The yarn itself has a certain buffering capacity for positional errors, and the width of the positioning tolerance zone is determined to be the second width ±0.3mm.

[0031] This invention dynamically adjusts the tolerance band width according to the spinning process stages. A stricter tolerance band is used in the small yarn stage to ensure yarn forming quality and uniformity of bobbin forming. The tolerance band is appropriately loosened in the medium and large yarn stages to avoid excessive pursuit of precision, which leads to frequent adjustments and reduced efficiency. This improves overall production efficiency while ensuring spinning quality, achieving a balance between precision and efficiency.

[0032] Step 103: Calculate the theoretical position deviation based on the current height position and the target height value, and correct the theoretical position deviation to obtain the corrected position deviation.

[0033] The theoretical position deviation refers to the difference between the current height and the target height, which is the distance the lifting mechanism needs to move; the corrected position deviation refers to the correction value obtained after applying pitch error compensation to the theoretical position deviation, which is used to eliminate the position deviation caused by screw manufacturing errors.

[0034] In a specific implementation of this invention, the difference between the current height position and the target height value is first calculated to obtain the theoretical position deviation. Then, based on the current height position, a pre-calibrated screw full-stroke pitch error compensation table is consulted to determine the deviation coefficient corresponding to the height segment where the current height position is located. Finally, the theoretical position deviation is multiplied by this deviation coefficient to obtain the corrected position deviation.

[0035] In some embodiments of the present invention, step 103, "correcting the theoretical position deviation to obtain the corrected position deviation," may specifically include the following sub-steps: Sub-step 1031: Based on the current height position, query the pre-stored pitch error compensation table to obtain the pitch ratio coefficient corresponding to the height segment where the current height position is located; Sub-step 1032: The product of the theoretical position deviation and the pitch proportionality coefficient is determined as the corrected position deviation; wherein, the pitch proportionality coefficient is the ratio of the measured pitch value of the screw in the lifting mechanism in the corresponding height section to the nominal pitch value.

[0036] Among them, the pitch ratio coefficient is the ratio of the measured pitch value of the screw in a specific height section to the nominal pitch value in the lifting mechanism, which can reflect the magnitude and direction of the pitch error in that section; the measured pitch value refers to the real pitch value obtained by measuring the screw section by section after the actual assembly by a precision measuring instrument; the nominal pitch value refers to the theoretical pitch value specified in the screw design drawings, which serves as the benchmark reference value for error calculation.

[0037] Continuing with the examples from steps 101 and 102, assuming the current height is 72mm and the target height is 150mm, the theoretical position deviation is 150 minus 72, which equals 78mm. Referring to the pre-calibrated pitch error compensation table, the measured pitch of the screw within the 72mm to 150mm height range is 9.97mm, while the nominal pitch is 10mm. Therefore, the deviation coefficient is... Multiplying the theoretical position deviation of 78mm by the deviation coefficient of 0.997 yields a corrected position deviation of 77.77mm.

[0038] This invention corrects the theoretical position deviation by using a pre-calibrated pitch error compensation table, enabling the position deviation calculation to provide differentiated compensation for the actual pitch characteristics of different sections of the screw, thereby improving the positioning consistency of the lifting mechanism throughout its entire stroke range.

[0039] Step 104: Determine the total resistance based on the load weight and mechanical installation tilt angle, and calculate the compensation torque of the servo motor based on the total resistance.

[0040] The total resistance refers to the sum of all the opposing forces that the servo motor needs to overcome during the movement of the lifting mechanism, including the component of gravity along the screw axis and friction. The component of gravity along the screw axis refers to the component of the load weight along the screw axis under the influence of the mechanical installation tilt angle. Friction refers to the force that opposes the relative motion between the screw and nut contact surfaces when the lifting mechanism moves. The compensation torque refers to the additional rotational torque that the servo motor needs to output to overcome the total resistance, which is calculated from the total resistance, screw lead, and transmission efficiency.

[0041] In a specific implementation of the present invention, the component of gravity along the screw axis and the frictional force to be overcome can be determined by the load weight and the installation tilt angle.

[0042] In some embodiments of the present invention, step 104, "determining the total resistance based on the load weight and the mechanical installation tilt angle," specifically includes the following sub-steps: Sub-step 1041: Calculate the component of gravity along the screw axis based on the load weight and mechanical installation tilt angle; Sub-step 1042: Determine the lubrication condition attenuation coefficient based on the cumulative value of screw running time, and determine the dynamic friction force based on the lubrication condition attenuation coefficient; Sub-step 1043: Summate the component of gravity along the screw axis and the dynamic friction to obtain the total resistance.

[0043] Among them, the lubrication condition decay coefficient is a correction factor that reflects the influence of the cumulative screw running time on the performance of the lubricating oil film and the coefficient of friction, and its value ranges from 0 to 1; the cumulative running time refers to the total running time of the screw from the first time it is put into use or the last time the lubricating oil is changed to the current moment; the dynamic friction force refers to the sliding friction resistance generated between the screw and the nut contact surface when the lifting mechanism moves, which changes dynamically with the lubrication condition.

[0044] In a specific implementation of this invention, the load weight is first converted into gravity. Then, the gravity is multiplied by the sine of the mechanical installation tilt angle to obtain the component of gravity along the screw axis. Next, the cumulative screw running time is read, and the corresponding lubrication state attenuation coefficient is determined based on a preset lubrication attenuation curve. The reference dynamic friction coefficient is multiplied by the lubrication state attenuation coefficient to obtain the corrected dynamic friction coefficient. Then, the gravity is multiplied by the cosine of the mechanical installation tilt angle and multiplied by the corrected dynamic friction coefficient to obtain the dynamic friction force. Finally, the component of gravity along the screw axis is added to the dynamic friction force to output the total resistance.

[0045] In a specific implementation of this invention, the lubrication condition decay coefficient is determined according to a preset decay curve based on the cumulative screw operating time. Timing begins when the screw is first put into use or after the last lubricant change, and the total operating time is recorded. When the cumulative screw operating time is less than 500 hours, the lubricating oil film is intact, the lubrication condition is good, the lubrication condition decay coefficient is 1.00, and the dynamic friction coefficient remains unchanged. When the cumulative operating time is between 500 and 1500 hours, the lubricating oil gradually oxidizes and carries abrasive particles, the lubrication condition decay coefficient linearly decreases to 0.95, and the dynamic friction coefficient increases accordingly. When the cumulative operating time is between 1500 and 2500 hours, the grease thickens, the oil film thins, and the lubrication condition decay coefficient decreases to 0.92. When the cumulative operating time exceeds 2500 hours, the lubrication condition severely deteriorates, and the lubrication condition decay coefficient drops below 0.88, indicating a need to replace the lubricating oil. The value of the lubrication condition decay coefficient can be adjusted according to actual operating conditions and lubricant type.

[0046] Continuing with the previous example, in sub-step 1041, the load weight is 20kg, the mechanical installation tilt angle is 2°, and the gravitational acceleration g is 9.8m / s². 2Therefore, the component of gravity along the screw axis is 20 × 9.8 × sin2° = 6.85 N. In sub-step 1042, the cumulative screw running time is 2000 hours, the lubrication attenuation coefficient is 0.92, the base dynamic friction coefficient is 0.15, the corrected dynamic friction coefficient is 0.15 × 0.92 = 0.138, and the dynamic friction force is 0.138 × 20 × 9.8 × cos2° = 26.98 N. In sub-step 1043, 6.85 N and 26.98 N are summed to obtain a total resistance of 33.83 N. If the screw lead is 10 mm (0.01 m), then the compensation torque required for the servo motor to overcome the resistance is calculated based on the total resistance. .

[0047] This invention decomposes the total resistance into two independent components: the axial component of gravity and the dynamic friction force. It also introduces a lubrication state attenuation coefficient based on running time to correct the dynamic friction force. This allows the calculation of the total resistance to reflect the changes in gravity load caused by the installation tilt angle and the impact of lubrication degradation on the friction force after long-term operation. This avoids the excessive deviation in resistance estimation at low speeds or in poor lubrication caused by using a fixed friction coefficient, and improves the accuracy of the compensation torque calculation and the adaptability of the lifting control.

[0048] Step 105: Calculate the axial elastic compression of the lifting mechanism based on the load weight, determine the first angle compensation amount corresponding to the axial elastic compression amount and the second angle compensation amount corresponding to the correction of the position deviation, and determine the target rotation angle based on the first angle compensation amount and the second angle compensation amount.

[0049] Among them, the axial elastic compression refers to the length of elastic deformation of the lifting mechanism along the axial direction under the action of load weight, which is determined by the load force and the stiffness coefficient of the lifting mechanism; the first angle compensation refers to converting the axial elastic compression into the additional angle value that the servo motor needs to rotate, in order to compensate for the position error caused by elastic deformation; the second angle compensation refers to converting the corrected position deviation into the angle value that the servo motor needs to rotate; the target rotation angle is the final angle position that the servo motor needs to reach from the current angle, which is obtained by superimposing the current angle, the second angle compensation, and the first angle compensation.

[0050] In a specific implementation of this invention, the axial elastic compression is obtained by dividing the load force corresponding to the load weight by the screw stiffness coefficient. The axial elastic compression is then divided by the nominal screw pitch and multiplied by 360° to obtain the first angle compensation. The corrected position deviation is divided by the nominal screw pitch and multiplied by 360° to obtain the second angle compensation. The target rotation angle is obtained by adding the current angle fed back by the rotary encoder, the second angle compensation, and the first angle compensation.

[0051] In some embodiments of the present invention, step 105, "determining the first angle compensation amount corresponding to the axial elastic compression amount," may specifically include the following sub-steps: Sub-step 1051: Determine the stiffness coefficient through the pre-constructed elastic deformation calculation model, and calculate the first angle compensation amount corresponding to the elastic compression amount through the stiffness coefficient. The elastic deformation calculation model represents the functional relationship between the stiffness coefficient of the lifting mechanism, the load weight and the axial deformation.

[0052] Among them, the elastic deformation calculation model is a preset function that describes the mathematical relationship between the stiffness coefficient, load weight and axial deformation of the lifting mechanism, and is used to calculate the amount of elastic deformation based on the load force; the stiffness coefficient refers to the parameter of the lifting mechanism's ability to resist axial elastic deformation, with the unit N / mm, which is determined by the elastic modulus, cross-sectional dimensions and effective length of the screw material; the axial deformation refers to the elastic compression or tension length of the lifting mechanism along the axial direction under the action of load force.

[0053] In the specific implementation of this invention, the construction process of the elastic deformation calculation model is as follows: First, the tensile and compressive stiffness of the screw itself is determined. The elastic modulus of the screw material is multiplied by the cross-sectional area of ​​the screw and then divided by the effective bearing length of the screw to obtain the screw body stiffness. Second, the nut contact stiffness is determined. The ratio of the elastic deformation of the nut thread under rated load to the load force is obtained through finite element simulation or actual measurement calibration. Then, the screw body stiffness and the nut contact stiffness are combined according to the spring series relationship. The reciprocal of the total stiffness is equal to the sum of the reciprocals of the screw body stiffness and the nut contact stiffness, thus obtaining the comprehensive stiffness coefficient of the lifting mechanism. This invention can also correct the theoretical comprehensive stiffness coefficient through actual measurement calibration of the lifting platform, taking into account actual factors such as bearing end deformation, connecting part clearance, and installation preload, to obtain the actual comprehensive stiffness coefficient. Finally, an elastic deformation calculation model is established, specifically, the axial elastic compression is equal to the load force divided by the actual comprehensive stiffness coefficient.

[0054] Taking the ring spinning machine in steps 101 to 104 as an example, an elastic deformation calculation model is constructed. The elastic modulus of the screw material is taken as 206 × 10⁻⁶. 3 MPa, screw root diameter 20mm, cross-sectional area 314mm² 2 The effective load-bearing length of the screw is 800mm, and the stiffness of the screw body is... Finite element simulation showed that the contact elastic deformation of the nut under a 200N load was 0.001mm, and the contact stiffness of the nut was 200÷0.001=2×10. 5 N / mm. Connecting the screw body stiffness and the nut contact stiffness in series, the reciprocal of the overall stiffness coefficient of the lifting mechanism is... The overall stiffness coefficient of the lifting mechanism is This invention also comprehensively considers factors such as bearing end deformation, connecting part clearance, and installation preload. Through actual measurement and calibration on the lifting platform, the actual comprehensive stiffness coefficient is approximately 20000 N / mm. When the load force is 196 N, the axial elastic compression is... Therefore, the first angle compensation amount corresponding to the elastic compression is .

[0055] Before or after determining the first angle compensation amount, the present invention further determines the second angle compensation corresponding to the corrected position deviation. Continuing with the previous example, if the corrected position deviation is 77.77, then the second angle compensation amount corresponding to the corrected position deviation is... The motor angle read at startup is 1800°. The final target rotation angle is the sum of the first angle compensation, the second angle compensation, and the motor angle at startup, which is 2799.72° + 0.353° + 1800° = 4600.1°.

[0056] Step 106: Generate motion trajectory information based on the target rotation angle and speed control information.

[0057] Among them, motion trajectory information refers to the data set of the servo motor’s speed changing over time as it rotates from the current angle to the target rotation angle, including at least the speed curve parameters of the acceleration phase, the constant speed phase, and the deceleration phase.

[0058] In some embodiments of the present invention, the motion trajectory information includes at least acceleration phase information, constant speed phase information, and deceleration phase information, and step 106 may specifically include the following sub-steps: Sub-step 1061: Obtain the actual torque output value and angular acceleration value of the historical lifting process.

[0059] Among them, the acceleration phase information refers to the motion parameters of the motor during the process of accelerating from a stationary speed to the maximum speed; the constant speed phase information refers to the motion parameters of the motor during the process of rotating at a constant speed at the maximum speed; and the deceleration phase information refers to the motion parameters of the motor during the process of decelerating from the maximum speed to the crawling speed.

[0060] In a specific implementation of the present invention, data is read from the peak value of motor torque and peak value of angular acceleration recorded in the previous or previous lifting processes. The peak value of torque in the present invention is taken from the torque register of the servo driver, and the angular acceleration value can be obtained by differentiating the speed feedback signal.

[0061] Sub-step 1062: Update the total inertia parameter by the ratio of the actual torque output value to the angular acceleration value; Divide the peak torque recorded during the previous lifting process by the peak angular acceleration to obtain the updated total inertia parameter. The ratio of torque to angular acceleration reflects the system's rotational inertia. This ratio is automatically updated when responding to a new lifting task, a change in load weight, or a system restart. Assuming data is read from the peak motor torque and peak angular acceleration recorded during the previous n lifting processes, calculate the ratio of the actual torque output value to the angular acceleration value in the n records, take the arithmetic mean of the n ratios, and update the total inertia parameter.

[0062] Sub-step 1063: Compare the updated total inertia parameter with the rated torque of the servo motor to obtain the maximum allowable acceleration value under the current working conditions.

[0063] In a specific implementation of the present invention, the rated torque of the servo motor is divided by the updated total inertia parameter to obtain the theoretical maximum acceleration value, and this theoretical maximum acceleration value is used as the maximum acceleration value allowed under the current working conditions; alternatively, the obtained maximum acceleration value can be multiplied by a safety factor to obtain the maximum acceleration value allowed under the current working conditions.

[0064] Sub-step 1064: Determine the acceleration phase information based on the maximum acceleration value, and calculate the deceleration phase information based on the width of the positioning tolerance band. The acceleration phase information includes at least the acceleration, and the deceleration phase information includes at least the starting position of the deceleration segment.

[0065] In a specific implementation of this invention, the maximum acceleration value obtained in sub-step 1063 is used as the acceleration of the acceleration phase. The starting position of the deceleration segment in the deceleration phase information is determined jointly based on the target rotation angle, the required deceleration stroke, and the width of the positioning tolerance band. The smaller the positioning tolerance band width, the farther the starting position of the deceleration segment is from the target rotation angle, ensuring that the lifting mechanism smoothly enters the positioning tolerance band at a crawling speed, avoiding position overshoot due to excessive speed. This invention converts the positioning tolerance band width into a motor angle tolerance, and determines the deceleration advance based on this angle tolerance; the smaller the angle tolerance, the larger the deceleration advance. The starting position of the deceleration segment is equal to the target rotation angle minus the required deceleration angle minus the deceleration advance.

[0066] Sub-step 1065: Based on the determined acceleration phase information and deceleration phase start position, plan and generate uniform speed phase information.

[0067] In a specific implementation of the present invention, a constant speed segment is planned between the end position of the acceleration segment and the beginning position of the deceleration segment. The speed of the constant speed segment is the maximum speed, and the length of the constant speed segment is equal to the starting position of the deceleration segment minus the end position of the acceleration segment.

[0068] Continuing with the example in steps 101 to 105, assume that the peak motor torque recorded during the previous lifting process was 2.8 N·m and the angular acceleration was 1200° / s². 2Converted to radian acceleration: Therefore, in substep 1062, the total inertia parameter is updated to 2.8 ÷ 20.94 ≈ 0.134 kg·m. 2 Assuming the servo motor's rated torque is 5 N·m, the theoretical maximum radian acceleration in substep 1063 is approximately 5 ÷ 0.134 ≈ 37.31 rad / s². 2 Converted to ° / s 2 for Multiply by a safety factor of 0.85 and round down to 1800° / s 2 Therefore, the time required to accelerate to the maximum speed of 1800° / s is 1800 ÷ 1800 = 1 second. The rotation angle during the acceleration phase is 0.5 × 1800 × 1 = 900°. The speed during the constant speed phase, which is also the maximum speed, is 1800° / s. If the crawling speed is 180° / s, the deceleration is 1500° / s. 2 Therefore, the deceleration time = (1800 - 180) ÷ 1500 = 1.08 seconds, and the angle required for deceleration is (1800). 2 -180 2 1) ÷ (2 × 1500) = 1069°. The tolerance band width of ±0.3mm is converted to a motor angle tolerance of ±10.8°. According to the preset calibration curve, the deceleration advance corresponding to an angle tolerance of 10.8° is measured as 21.6°. The target rotation angle is 4600.1°, and the starting position of the deceleration segment is 4600.1° - 1069° - 21.6° = 3508.4°. When the motor angle reaches 3508.4°, the deceleration speed begins at -1500° / s. 2 During deceleration, the motor angle at the end of the deceleration phase is approximately 4600.1° - 21.6° = 4578.5°. This angle falls within the tolerance range of ±10.8°, and the speed decreases to a crawling speed of 180° / s. The acceleration phase ends at the current angle of 1800° plus the acceleration phase rotation angle of 900°, which equals 2700°. The deceleration phase begins at 3508.4°. The constant speed phase is located between 2700° and 3508.4°, with a length of 808.4°. The time required for constant rotation at 1800° / s is approximately 844.4 ÷ 1800 ≈ 0.45 seconds.

[0069] As shown in the above examples, in specific implementations of the present invention, the acceleration phase information includes not only the acceleration value but also the acceleration duration; the constant speed phase information includes not only the starting position of the constant speed segment but also the distance of the constant speed segment; and the deceleration phase information includes not only the starting position of the deceleration segment but also the deceleration value.

[0070] Step 107: The position of the servo motor of the lifting mechanism is controlled by the motion trajectory information, and the compensation torque is converted into a feedforward current command to perform feedforward control on the servo motor.

[0071] Among them, the servo motor position refers to the angular displacement or rotation angle of the servo motor rotor, in degrees or radians; the feedforward current command refers to the control quantity that is directly injected into the current loop after the compensation torque is converted into a current value, without going through the error accumulation of the position loop and speed loop.

[0072] In some embodiments of the present invention, the servo motor includes a position loop and a speed loop, and the lifting mechanism is equipped with a rotary encoder. Step 107, "controlling the position of the servo motor of the lifting mechanism using motion trajectory information," may specifically include the following sub-steps: Sub-step 1071: Generate a position command sequence based on the motion trajectory, and calculate the tracking error by combining the motor angle feedback from the rotary encoder in real time.

[0073] Among them, the position command sequence refers to a series of target angle values ​​generated according to a fixed control cycle, and a desired angular position is sent to the position loop controller in each cycle; the tracking error refers to the difference between the command angle in the position command sequence and the actual angle fed back by the rotary encoder in real time.

[0074] In a specific implementation of the present invention, the servo driver sends a position command value to the position loop controller in each control cycle according to the planned motion trajectory, so that the servo motor moves to the expected angle position in the position command value. At the same time, it reads the actual angle of the motor fed back by the rotary encoder in real time, and subtracts the feedback angle from the position command value to obtain the tracking error of the current cycle.

[0075] Sub-step 1072: Adjust the proportional gain of the position loop according to the tracking error. When the tracking error is greater than the width of the position tolerance band, adjust the proportional gain to the first gain value; when the tracking error falls within the width of the position tolerance band, adjust the proportional gain to the second gain value, wherein the first gain value is greater than the second gain value.

[0076] Among them, the proportional gain refers to the coefficient used in the position loop controller to amplify the tracking error to generate speed commands. The larger the gain value, the faster the position response. The first gain value in this invention refers to the high proportional gain used when the tracking error is large, which is used to speed up the position response. The second gain value in this invention refers to the low proportional gain used after the tracking error enters the tolerance band, which is used to suppress overshoot and oscillation.

[0077] In a specific implementation of this invention, the relationship between the absolute value of the current tracking error and the width of the position tolerance band is first determined. If the tracking error is greater than the width of the position tolerance band, it indicates that the current position deviation is large and a rapid response is required. In this case, the position loop proportional gain is set to a higher first gain value. If the tracking error has already entered the range of the position tolerance band width, it indicates that the current position is close to the target and a smooth entry is required. In this case, the position loop proportional gain is reduced to a second gain value to avoid overshoot and oscillation caused by high gain.

[0078] Continuing with the previous example, the target rotation angle is 4600.1°, and the position tolerance band width is converted to a motor angle ±10.8°. In sub-step 1071, the servo driver generates a position command every 1ms. Assuming the position command is 3500° at the 2.5-second mark, the rotary encoder feedback angle is 3495°, and the tracking error is 5°, sub-step 1072 determines that 5° is less than 10.8°, meaning the tracking error falls within the position tolerance band width. Therefore, the position loop proportional gain is reduced from the default value of 8 to the second gain value of 3 to suppress overshoot. If the tracking error determined at the 1.5-second mark is 500°, which is greater than 10.8°, the proportional gain is increased to the first gain value of 12 to speed up the response.

[0079] In some embodiments of the present invention, step 107, "converting the compensation torque into a feedforward current command to perform feedforward control on the servo motor," may specifically include the following sub-steps: Sub-step 1073: During the acceleration phase, calculate the first feedforward current based on the maximum acceleration value and the total inertia parameter, and superimpose it on the drive current of the servo motor; Sub-step 1074: During the constant speed phase, calculate the second feedforward current based on the total resistance and add it to the drive current of the servo motor, wherein the second feedforward current is less than the first feedforward current.

[0080] The first feedforward current is the feedforward current component used to overcome the inertial load during the acceleration phase, calculated based on the maximum acceleration value and the total inertia parameter; the second feedforward current is the feedforward current component used to overcome the total resistance during the constant velocity phase, calculated based on the total resistance.

[0081] In a specific implementation of this invention, firstly, the current motion stage is determined. If it is in the acceleration stage, the maximum acceleration value obtained in sub-step 1063 and the total inertia parameter updated in sub-step 1062 are read. The maximum acceleration value is multiplied by the total inertia parameter to obtain the torque required for acceleration. This torque is then converted into a feedforward current command and superimposed on the given current of the servo driver current loop. If it is in the constant speed stage, the total resistance calculated in step 104 is read. The total resistance is converted into torque on the motor shaft and then converted into a feedforward current command and superimposed on the given current of the servo driver current loop.

[0082] Continuing with the previous example, the acceleration phase in sub-step 1073 lasts from 0 to 1 second, with a maximum acceleration value of 31.4 rad / s². 2 Total inertia parameter: 0.134 kg·m 2The acceleration torque is 31.4 × 0.134 ≈ 4.21 N·m, the motor torque constant is 0.2 N·m / A, and the first feedforward current is 4.21 ÷ 0.2 ≈ 21.05 A. In sub-step 1074, the constant speed stage lasts from 1 second to approximately 1.47 seconds, the total resistance is 33.83 N, the screw lead is 10 mm, the resistance torque is 33.83 × 0.01 ÷ (2π) ≈ 0.054 N·m, and the second feedforward current is 0.054 ÷ 0.2 ≈ 0.27 A.

[0083] In some embodiments of the present invention, the above method may further include the following steps: When the motor angle enters the positioning tolerance zone corresponding to the target rotation angle, and the speed of the lifting mechanism is lower than the crawling speed threshold and continues to exceed the judgment time, a positioning completion signal is output.

[0084] Among them, the crawling speed threshold refers to the speed limit value for determining whether the lifting mechanism is close to stopping. If the speed is lower than this, the lifting mechanism is considered to be in a low-speed crawling state. The judgment time refers to the continuous stable time for the lifting mechanism to simultaneously meet the position and speed conditions, which is used to eliminate misjudgments caused by instantaneous disturbances. The completion signal is a sign that the lifting action has been completed and notifies the main control system of the spinning machine.

[0085] In a specific implementation of this invention, the motor angle fed back by the rotary encoder is monitored in real time to determine whether the absolute value of the deviation between the motor angle and the target rotation angle is less than or equal to the angle tolerance corresponding to the width of the positioning tolerance band. Simultaneously, the movement speed of the lifting mechanism is monitored to determine whether the absolute value of the speed is lower than a preset crawling speed threshold. Timing begins when both conditions are met simultaneously. If both conditions are consistently met within a continuous judgment period, the lifting is determined to be in place, and a completion signal is output to the spinning machine's main control system. If either condition is not met during the timing process, the timer is reset and the system continues to wait.

[0086] Continuing with the previous example, the target rotation angle is 4600.1°, the positioning tolerance band width of ±0.3mm translates to a motor angle tolerance of ±10.8°, the crawling speed threshold is set to 180° / s, and the judgment time is set to 100ms. At 2.53 seconds, the rotary encoder feedback angle is 4599.9°, which deviates from the target angle of 4600.1° by -0.2°, and the absolute value is less than 10.8°, meaning the position condition is met. At this time, the lifting mechanism speed is 180° / s, equal to the crawling speed threshold of 180° / s, thus the speed condition is met. Timing begins after both conditions are met. During the 100ms period, the feedback angle fluctuates between 4599.9° and 4600.1°, and the speed varies between 170° / s and 180° / s. After the 100ms judgment time ends, a positioning completion signal is output to the main control system at 2.63 seconds.

[0087] This invention avoids the problem of misjudging a position based solely on position conditions, which can occur when the position is momentarily within the tolerance zone. The continuous stability determination time requires the lifting mechanism to maintain low-speed, stable operation within the tolerance zone for a period of time, thus improving the reliability and stability of the positioning determination.

[0088] In some embodiments of the present invention, the above method may further include the following steps: Obtain the current temperature information of the screw in the lifting mechanism; Based on the difference between the current temperature and the preset reference temperature, and combined with the thermal expansion coefficient and length of the screw, the thermal elongation of the screw is calculated. The thermal elongation is converted into a third angle compensation and added to the target rotation angle.

[0089] The preset reference temperature refers to the initial temperature of the screw in a cold state, which can be the ambient temperature or the measured temperature when the equipment is started. The coefficient of thermal expansion is the elongation per unit length of the screw material when the temperature increases by one degree Celsius. Thermal elongation refers to the increase in axial length of the screw relative to the reference temperature due to the temperature increase. The third angle compensation is the conversion of the thermal elongation into an additional angle value that the servo motor needs to rotate, used to compensate for the positional error caused by thermal deformation. In a specific implementation of this invention, the coefficient of thermal expansion varies depending on the material. When the screw is made of steel, the coefficient of thermal expansion is 11.7 × 10⁻⁶. -6 / ℃. The screw temperature is collected in real time by a temperature sensor installed on the lifting mechanism and used as the current screw temperature. This current temperature is subtracted from the preset reference temperature to obtain the temperature difference. The temperature difference is multiplied by the coefficient of thermal expansion and then by the screw length to obtain the thermal elongation. The thermal elongation is divided by the nominal screw pitch and then multiplied by 360° to obtain the third angle compensation. The third angle compensation is added to the original target rotation angle to obtain the final target rotation angle after compensating for the thermal elongation.

[0090] Taking the ring spinning machine in steps 101 to 108 as an example, the temperature sensor is installed near the fixed end of the screw, and the real-time screw temperature is read as 42℃, while the preset reference temperature is 22℃, with a temperature difference of 20℃. The coefficient of thermal expansion of the screw material is taken as 11.7×10⁻⁶. -6 / ℃, the effective length of the screw is 800mm, and the thermal elongation is 20×11.7×10. -6×800 = 0.1872mm. The nominal screw pitch is 10mm; therefore, the third angle compensation is 0.1872 ÷ 10 × 360° ≈ 6.74°. The original target rotation angle is 4635°. After adding the third angle compensation, the final target rotation angle is updated to 4641.74°. The servo motor performs position control according to the updated target rotation angle to compensate for the height drift of the steel collar plate caused by the thermal expansion of the screw.

[0091] The above steps comprehensively consider thermal elongation compensation, elasticity compensation, and pitch error compensation to address positional errors from three different sources: load deformation, manufacturing error, and thermal deformation, thereby achieving high-precision positioning under all working conditions.

[0092] In some embodiments of the present invention, an anomaly handling process is triggered when the tracking deviation exceeds a preset safety threshold. This process includes reducing the movement speed to a safe speed, increasing the feedforward compensation torque, or issuing a fault alarm signal. For example, if the encoder feedback angle and command deviation suddenly increase to 2.5mm at the 2nd second, exceeding the safety threshold of 2mm, the anomaly handling process immediately reduces the speed to the safe speed of 30mm / s and simultaneously increases the feedforward compensation torque to 0.08N·m. Normal operation resumes after the anomaly is eliminated. During each lifting task, the position accuracy, response time, and peak motor torque data can also be recorded for subsequent inertia identification and performance optimization.

[0093] In summary, this invention achieves high-precision, rapid, and stable lifting of the lifting mechanism throughout the entire spinning cycle by correcting position deviations, compensating for torque, compensating for elastic angles, trajectory planning, and feedforward control, combined with a motor position control method based on spinning process stage parameters, thereby improving spinning quality and production efficiency.

[0094] Reference Figure 2 The diagram shows the structure of the servo motor position control system for the lifting mechanism of a ring spinning frame. The system includes: Data acquisition module 201 is used to acquire the current height position, load weight and mechanical installation tilt angle of the ring spinning machine lifting mechanism; The control information determination module 202 is used to respond to a lifting command and determine speed control information and position tolerance band width based on the lifting command. The lifting command includes at least a target height value and a process stage identifier. The correction module 203 is used to calculate the theoretical position deviation based on the current height position and the target height value, and to correct the theoretical position deviation to obtain the corrected position deviation; The first compensation module 204 is used to determine the total resistance based on the load weight and the mechanical installation tilt angle, and to calculate the compensation torque of the servo motor based on the total resistance. The second compensation module 205 is used to calculate the axial elastic compression of the lifting mechanism based on the load weight, determine the first angle compensation amount corresponding to the axial elastic compression amount and the second angle compensation amount corresponding to the corrected position deviation, and determine the target rotation angle based on the first angle compensation amount and the second angle compensation amount. The trajectory generation module 206 is used to generate motion trajectory information based on the target rotation angle and the speed control information; The control module 207 is used to control the position of the servo motor of the lifting mechanism using the motion trajectory information, and to convert the compensation torque into a feedforward current command to perform feedforward control on the servo motor.

[0095] As the system implementation is basically similar to the method implementation, it is described in a relatively simple way. For relevant details, please refer to the description of the method implementation.

[0096] This invention also provides an electronic device that may include a processor, a memory, and a computer program stored in the memory and capable of running on the processor. When the computer program is executed by the processor, it implements the method described above.

[0097] This invention also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, it implements the method described above.

[0098] The specific embodiments described above are preferred embodiments of the present invention and are not intended to limit the specific scope of the present invention. The scope of the present invention includes, but is not limited to, these specific embodiments. All equivalent changes made in accordance with the shape and structure of the present invention are within the protection scope of the present invention.

Claims

1. A servo motor position control method for the lifting mechanism of a ring spinning frame, characterized in that, include: Obtain the current height position, load weight, and mechanical installation tilt angle of the ring spinning machine lifting mechanism; In response to a lifting command, speed control information and positioning tolerance band width are determined based on the lifting command, wherein the lifting command includes at least a target height value and a process stage identifier; The theoretical position deviation is calculated based on the current height position and the target height value, and the theoretical position deviation is corrected to obtain the corrected position deviation; The total resistance is determined based on the load weight and the mechanical mounting angle, and the compensation torque of the servo motor is calculated based on the total resistance. The axial elastic compression of the lifting mechanism is calculated based on the load weight. The first angle compensation amount corresponding to the axial elastic compression amount and the second angle compensation amount corresponding to the corrected position deviation are determined. The target rotation angle is determined based on the first angle compensation amount and the second angle compensation amount. Motion trajectory information is generated based on the target rotation angle and the speed control information; The motion trajectory information is used to control the position of the servo motor of the lifting mechanism, and the compensation torque is converted into a feedforward current command to perform feedforward control on the servo motor.

2. The method according to claim 1, characterized in that, The step of correcting the theoretical position deviation to obtain the corrected position deviation includes: Based on the current height position, query the pre-stored pitch error compensation table to obtain the pitch ratio coefficient corresponding to the height segment where the current height position is located; The product of the theoretical position deviation and the pitch ratio coefficient is determined as the corrected position deviation; wherein, the pitch ratio coefficient is the ratio of the measured pitch value of the screw in the lifting mechanism in the corresponding height section to the nominal pitch value.

3. The method according to claim 1, characterized in that, The determination of total resistance based on the load weight and the mechanical installation tilt angle includes: Calculate the axial component of gravity along the screw based on the load weight and the mechanical installation tilt angle; The lubrication condition attenuation coefficient is determined based on the cumulative value of the screw running time, and the dynamic friction force is determined based on the lubrication condition attenuation coefficient. The total resistance is obtained by summing the component of gravity along the screw axis and the dynamic friction force.

4. The method according to claim 1, characterized in that, Determining the first angle compensation amount corresponding to the axial elastic compression includes: The stiffness coefficient is determined by a pre-constructed elastic deformation calculation model, and the first angle compensation amount corresponding to the elastic compression amount is calculated by the stiffness coefficient. The elastic deformation calculation model represents the functional relationship between the stiffness coefficient of the lifting mechanism, the load weight and the axial deformation.

5. The method according to claim 1, characterized in that, The motion trajectory information includes at least acceleration phase information, constant speed phase information, and deceleration phase information. The step of generating motion trajectory information based on the target rotation angle and the speed control information includes: Obtain the actual torque output value and angular acceleration value during the historical lifting process; The total inertia parameter is updated by the ratio of the actual torque output value to the angular acceleration value; The updated total inertia parameter is compared with the rated torque of the servo motor to obtain the maximum allowable acceleration value under the current operating conditions; The acceleration phase information is determined based on the maximum acceleration value, and the deceleration phase information is calculated based on the position tolerance band width. The acceleration phase information includes at least acceleration, and the deceleration phase information includes at least the starting position of the deceleration segment and the deceleration segment acceleration. Based on the determined acceleration phase information and deceleration phase start position, the constant speed phase information is planned and generated.

6. The method according to claim 1, characterized in that, The servo motor includes a position loop and a speed loop, and the lifting mechanism is equipped with a rotary encoder. Controlling the position of the servo motor of the lifting mechanism using the motion trajectory information includes: A position command sequence is generated based on the motion trajectory, and the tracking error is calculated by combining the motor angle fed back in real time by the rotary encoder. The proportional gain of the position loop is adjusted according to the tracking error. When the tracking error is greater than the width of the position tolerance band, the proportional gain is adjusted to a first gain value. When the tracking error falls within the width of the position tolerance band, the proportional gain is adjusted to a second gain value, wherein the first gain value is greater than the second gain value.

7. The method according to claim 5, characterized in that, The step of converting the compensated torque into a feedforward current command to perform feedforward control on the servo motor includes: During the acceleration phase, a first feedforward current is calculated based on the maximum acceleration value and the total inertia parameter and then superimposed on the drive current of the servo motor. During the constant speed phase, a second feedforward current is calculated based on the total resistance and superimposed on the drive current of the servo motor, wherein the second feedforward current is less than the first feedforward current.

8. The method according to claim 6, characterized in that, The method further includes: When the motor angle enters the positioning tolerance zone corresponding to the target rotation angle, and the speed of the lifting mechanism is lower than the crawling speed threshold and continues to exceed the judgment time, a positioning completion signal is output.

9. The method according to claim 1, characterized in that, The process stage identifiers include the small yarn stage, medium yarn stage, and large yarn stage. The determination of speed control information and the positioning tolerance band width based on the lifting command includes: When the process stage is identified as the small yarn stage, the width of the arrival tolerance band is determined as the first width; When the process stage is identified as the medium yarn stage or the large yarn stage, the width of the positioning tolerance band is determined as the second width, wherein the first width is smaller than the second width.

10. The method according to claim 1, characterized in that, The method further includes: Obtain the current temperature information of the screw in the lifting mechanism; Based on the difference between the current temperature and the preset reference temperature, and in conjunction with the thermal expansion coefficient and length of the screw, the thermal elongation of the screw is calculated. The thermal elongation is converted into a third angle compensation amount and added to the target rotation angle.

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