Positioning error segmented control method and device for direct drive rotary table

Abstract

This invention provides a segmented control method and apparatus for positioning errors of a direct-drive turntable. The method includes: performing electromechanical coupling impedance analysis based on the full-circumference angles of the turntable and the corresponding drive current feedback sequence to obtain the full-circumference mechanical impedance distribution; performing multi-dimensional spatial topology segmentation based on the full-circumference mechanical impedance distribution to obtain sub-regions of each angle and their corresponding boundaries; performing path allocation based on each sub-region of each angle and its corresponding boundaries to obtain position tracking control paths and damping control paths corresponding to each sub-region of each angle; performing path analysis based on the position tracking control paths and damping control paths to obtain a composite control direction for the current angle; and distributing torque output based on the composite control direction and real-time position deviation to obtain the drive current command for the direct-drive turntable. This invention improves the positioning accuracy of the direct-drive turntable in local angle intervals and achieves uniform positioning control of the direct-drive turntable within the full-circumference range.

Description

Technical Field

[0001] This invention relates to the field of computer technology, and in particular to a method and apparatus for segmented control of positioning error for direct-drive rotary tables. Background Technology

[0002] In precision manufacturing, photoelectric tracking, and aerospace fields, direct-drive rotary tables serve as core actuators, and their positioning accuracy and dynamic stability directly determine the overall system performance. Existing control methods for direct-drive rotary tables typically employ proportional-integral-derivative (PID) control strategies based on a uniform gain throughout the entire stroke, or linear compensation methods based on a single global error compensation table. These methods treat the rotation range of the rotary table as a linear or quasi-linear overall space, neglecting the differential dynamic characteristics arising from changes in mechanical structure deformation due to gravity, nonlinear variations in bearing friction torque, and motor cogging effects as the position changes when pointing to different azimuth angles.

[0003] However, the use of globally unified control parameters or a single linear compensation model cannot adapt to the non-uniform error distribution characteristics exhibited by direct-drive turntables in different angle ranges. Specifically, when the turntable operates in certain specific angle ranges, the static deviation caused by changes in the gravitational component and the dynamic hysteresis caused by frictional nonlinearity are coupled, causing the global control strategy to over-compensate or under-compensate in these local ranges. More seriously, traditional methods often conflate "fast tracking" with "vibration suppression," failing to provide sufficient driving force in angle ranges requiring high-rigidity tracking, and failing to provide effective damping in angle ranges prone to elastic vibration. This results in a decrease in positioning accuracy in local areas, accompanied by residual oscillations, making it difficult to achieve uniform positioning control within the circumferential range. Summary of the Invention

[0004] This invention provides a segmented control method and apparatus for positioning error of a direct-drive turntable, aiming to solve the technical problems in the background art, improve the positioning accuracy of the direct-drive turntable in a local angle range, and realize uniform positioning control of the direct-drive turntable in the full circumference range.

[0005] In a first aspect, the present invention provides a segmented control method for positioning errors of a direct-drive rotary table, comprising:

[0006] Electromechanical coupling impedance analysis was performed based on the full circumferential angle of the direct-drive turntable and the corresponding drive current feedback sequence to obtain the full circumferential mechanical impedance distribution.

[0007] Based on the full-circumference mechanical impedance distribution, multi-dimensional spatial topology segmentation is performed to obtain angular sub-regions with homogeneous force characteristics and corresponding region boundaries.

[0008] Path allocation is performed based on each angle sub-region and its corresponding region boundary to obtain the position tracking control path and damping control path corresponding to each angle sub-region. Path analysis is then performed based on the position tracking control path and the damping control path to obtain the composite control direction for the current angle.

[0009] Based on the composite control direction and real-time position deviation, torque output is distributed to obtain the drive current command for the direct-drive turntable.

[0010] In a second aspect, the present invention also provides a positioning error segmentation control device for a direct-drive turntable, used to implement the positioning error segmentation control method for a direct-drive turntable as described in the first aspect; the positioning error segmentation control device for a direct-drive turntable includes:

[0011] The coupling impedance analysis module is used to perform electromechanical coupling impedance analysis based on the full circumferential angle of the direct drive turntable and the corresponding drive current feedback sequence, so as to obtain the full circumferential mechanical impedance distribution.

[0012] The spatial topology module is used to perform multi-dimensional spatial topology segmentation based on the full-circumference mechanical impedance distribution to obtain angular sub-regions with homogeneous force characteristics and corresponding region boundaries.

[0013] The composite control module is used to allocate paths based on each angle sub-region and its corresponding region boundary, obtain position tracking control paths and damping control paths corresponding to each angle sub-region, and perform path analysis based on the position tracking control paths and the damping control paths to obtain the composite control direction for the current angle.

[0014] The torque output distribution module is used to distribute torque output based on the composite control direction and real-time position deviation to obtain the drive current command of the direct drive turntable.

[0015] Thirdly, the present invention also provides an electronic device, comprising: a memory for storing computer software programs; and a processor for reading and executing the computer software programs, thereby realizing the segmented positioning error control method for direct-drive turntables as described above.

[0016] Fourthly, the present invention also provides a non-transitory computer-readable storage medium storing a computer software program, which, when executed by a processor, implements the positioning error segmentation control method for a direct-drive turntable as described above.

[0017] Fifthly, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the segmented control method for positioning error of a direct-drive turntable as described above.

[0018] The positioning error segmentation control method for direct-drive turntables provided in this invention analyzes the electromechanical coupling impedance of the full-circumference angle and corresponding drive current feedback sequence of the turntable to obtain the full-circumference mechanical impedance distribution. This allows for precise quantification of the dynamic characteristics of the turntable at different azimuth angles, thus clearly capturing the differential dynamic characteristics caused by the mechanical structure's gravity deformation, the nonlinear change of bearing friction torque, and the motor cogging effect as position changes. This breaks the inherent limitation of treating the turntable's rotation range as a linear or quasi-linear overall space. Based on the full-circumference mechanical impedance distribution, multi-dimensional spatial topology segmentation is performed to divide the entire circle according to the consistency of dynamic characteristics, obtaining angular sub-regions with homogeneous force characteristics and their corresponding region boundaries. Therefore, the originally complex and non-uniform full-circumference error distribution is decomposed into multiple local intervals with unified characteristics and easy control, solving the pain point that global control strategies cannot adapt to non-uniform error distributions in different angular intervals. Based on the angle sub-regions and their boundaries, targeted path allocation is performed to obtain the position tracking control path and damping control path corresponding to each sub-region. Then, the composite control direction corresponding to the current angle is determined through path analysis. This achieves regional and differentiated control of "rapid tracking" and "vibration suppression," effectively avoiding the problem of insufficient driving force in high-rigidity tracking intervals and ineffective damping in easily vibrating intervals caused by treating the two in the same way, thus refining the control accuracy. Guided by the composite control direction and combined with the real-time position deviation, torque output is allocated to generate the drive current command for the direct-drive turntable. This allows the turntable to obtain a control output highly adapted to its own dynamic characteristics in each angle sub-region. This solves the technical problem in the background technology where the positioning accuracy decreases in local areas and is accompanied by residual oscillations due to the use of a globally unified control strategy. It improves the positioning accuracy of the direct-drive turntable in local angle intervals and achieves uniform positioning control of the direct-drive turntable within the entire circumference. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the segmented positioning error control method for a direct-drive rotary table provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the positioning error segmentation control device for direct-drive turntable provided in an embodiment of the present invention;

[0021] Figure 3 An embodiment diagram of the electronic device provided in this invention;

[0022] Figure 4 An embodiment diagram of a computer-readable storage medium provided in accordance with the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] See Figure 1 , Figure 1 This is a flowchart illustrating the segmented positioning error control method for a direct-drive turntable provided by the present invention. In this embodiment, the executing entity of the segmented positioning error control method for a direct-drive turntable is the turntable control device. Therefore, the segmented positioning error control method for a direct-drive turntable includes:

[0025] Step 10: Perform electromechanical coupling impedance analysis based on the full circumferential angle of the direct-drive turntable and the corresponding drive current feedback sequence to obtain the full circumferential mechanical impedance distribution.

[0026] Optionally, the turntable control device controls the direct-drive turntable to perform continuous full-circumference rotation, covering the rotational stroke of the turntable, i.e., the complete circumferential angle range from 0 degrees to 360 degrees. During the full-circumference rotation of the direct-drive turntable, the turntable control device collects the full-circumferential angle sequence and the corresponding drive current feedback sequence. The full-circumferential angle sequence refers to all angle data collected at preset sampling intervals during the rotation of the direct-drive turntable from 0 degrees to 360 degrees. The preset sampling interval can be set according to the accuracy requirements of the direct-drive turntable, typically between 0.1 degrees and 1 degree. The drive current feedback sequence refers to the actual output current feedback data of the direct-drive turntable drive motor, corresponding one-to-one with each angle data in the full-circumferential angle sequence. This data is obtained in real-time by the current acquisition module of the turntable control device, reflecting the drive load of the direct-drive turntable at different angular positions.

[0027] The turntable control device performs synchronous alignment processing on the full circumferential angle sequence and the corresponding drive current feedback sequence to ensure that each angle data can correspond to a unique drive current feedback data.

[0028] After synchronization and alignment are completed, the turntable control device initiates the electromechanical coupling impedance analysis process. Electromechanical coupling impedance analysis refers to the process of obtaining impedance parameters reflecting the mechanical characteristics of the direct-drive turntable by analyzing the correlation between the drive current and mechanical response at different angular positions. Mechanical impedance refers to the direct-drive turntable's resistance to external excitation, and its magnitude reflects the turntable's rigidity, damping, and other mechanical characteristics at that angular position. Specifically, each angle in the full-circumference angle sequence is used as an analysis node. For each analysis node, the drive current feedback data corresponding to that angle is extracted. Combined with the mechanical structural parameters of the direct-drive turntable (including known fixed parameters such as turntable surface mass, moment of inertia, and bearing stiffness), the mechanical impedance value at that angular position is calculated through mechanical equilibrium analysis.

[0029] Among them, the mechanical equilibrium relationship analysis refers to the reverse derivation of the mechanical impedance value based on Newton's second law and the balance relationship between the electromagnetic torque generated by the driving current and the resistance torque generated by the mechanical impedance. That is, the actual electromagnetic torque is calculated by the driving current feedback data, and the resistance torque is obtained according to the motion state of the turntable at that angle position (in the state of uniform rotation, the electromagnetic torque and the resistance torque are equal). Then, the mechanical impedance value is calculated according to the correlation between the resistance torque, mechanical impedance and motion speed.

[0030] The above analysis and calculations are performed on each analysis node in the full-circumference angle sequence to obtain the mechanical impedance value corresponding to each angular position. All angular positions are then correlated with their corresponding mechanical impedance values ​​to form a full-circumference mechanical impedance distribution. Therefore, the full-circumference mechanical impedance distribution refers to the correspondence between each angular position and its corresponding mechanical impedance value within the full circumference range of 0 to 360 degrees for a direct-drive turntable, reflecting the differences in mechanical characteristics of the turntable at different angular positions.

[0031] Step 20: Perform multi-dimensional spatial topology segmentation based on the full-circumference mechanical impedance distribution to obtain angle sub-regions with homogeneous force characteristics and their corresponding region boundaries.

[0032] Optionally, the turntable control device uses a multi-dimensional spatial topology segmentation method to divide the full-circumference angle range of the direct-drive turntable based on the full-circumference mechanical impedance distribution. Multi-dimensional spatial topology segmentation treats the full-circumference mechanical impedance distribution as a multi-dimensional data space, using the numerical characteristics of the mechanical impedance as the segmentation index. Angle positions with similar mechanical impedance values ​​and consistent mechanical characteristics are grouped into the same region, i.e., angle sub-regions with homogeneous force characteristics. Homogeneous force characteristics mean that the difference in mechanical impedance values ​​of the direct-drive turntable at all angle positions within this region is within a preset threshold range, and the mechanical stiffness, damping, and other mechanical characteristics are basically consistent.

[0033] During the segmentation process, the turntable control device identifies abrupt changes in the mechanical impedance distribution and uses these abrupt changes as the region boundaries to obtain several independent and continuously distributed angle sub-regions, as well as the starting angle and ending angle (i.e., region boundaries) corresponding to each angle sub-region. The range of all angle sub-regions covers the full circumferential angle range of the direct drive turntable, as described in steps 201 to 204.

[0034] Step 30: Path allocation is performed based on each angle sub-region and its corresponding region boundary to obtain the position tracking control path and damping control path corresponding to each angle sub-region. Path analysis is then performed based on the position tracking control path and damping control path to obtain the composite control direction for the current angle.

[0035] Optionally, the turntable control device allocates control paths based on each angular sub-region and its corresponding region boundary. Path allocation combines the homogeneous force characteristics of each angular sub-region to configure a corresponding position tracking control path and damping control path for each angular sub-region, as detailed in steps 301 to 304. The position tracking control path refers to the control process path used to enable the direct-drive turntable to accurately track the target position within that angular sub-region. The damping control path refers to the control process path used to suppress any elastic vibrations that may occur in the direct-drive turntable within that angular sub-region.

[0036] The turntable control device acquires the current angle of the direct-drive turntable in real time, determines the angle sub-region to which the current angle belongs, calls the position tracking control path and damping control path corresponding to the angle sub-region, performs a fusion analysis on the control process of the two paths, and determines the composite control direction for the current angle, as shown in steps 305 to 308. The composite control direction refers to the control direction that takes into account both position tracking accuracy and vibration suppression effect, and clarifies the priority and synergistic relationship between position tracking and damping suppression in the current control process.

[0037] Step 40: Based on the composite control direction and real-time position deviation, torque output is distributed to obtain the drive current command for the direct drive turntable.

[0038] Optionally, the turntable control device collects the current actual position of the direct-drive turntable, compares the current actual position with the preset target position, and calculates the real-time position deviation. The current actual position is detected in real-time by the turntable control device's position detection module (such as an encoder), accurately reflecting the current angular position of the direct-drive turntable. The preset target position refers to the angular position that the direct-drive turntable needs to reach, which is sent from the upper-level control system to the turntable control device. The real-time position deviation is the difference between the current actual position and the preset target position. A positive difference indicates that the current actual position is ahead of the target position, while a negative difference indicates that the current actual position is behind the target position. The absolute value of the difference reflects the severity of the position deviation.

[0039] After acquiring the composite control direction and real-time position deviation, the turntable control device distributes the torque output based on both. The torque output distribution involves determining the allocation ratio of position tracking torque and damping torque according to the composite control direction, calculating the required total output torque based on the magnitude and direction of the real-time position deviation, and then decomposing the total output torque into position tracking torque and damping torque according to the allocation ratio.

[0040] Position tracking torque refers to the torque used to drive the direct-drive turntable to move towards the target position and eliminate real-time position deviation. Its magnitude is positively correlated with the absolute value of the real-time position deviation; the larger the position deviation, the larger the position tracking torque. Its direction is opposite to the direction of the position deviation (i.e., if the deviation is positive, the position tracking torque is in the opposite direction, causing the turntable to decelerate; if the deviation is negative, the position tracking torque is in the positive direction, causing the turntable to accelerate). Damping torque refers to the torque used to suppress the vibration of the direct-drive turntable. Its magnitude is determined based on the priority of damping control in the composite control direction and the mechanical impedance characteristics of the current angle sub-region. Regions with lower mechanical impedance and greater susceptibility to vibration have a higher proportion of damping torque, and vice versa. The direction of the damping torque is opposite to the rotation direction of the turntable, used to provide damping resistance and suppress residual oscillations.

[0041] The turntable control device synthesizes the position tracking torque and damping torque to obtain the total driving torque of the direct-drive turntable. Based on the torque-current conversion relationship of the direct-drive turntable's drive motor, the total driving torque is converted into a corresponding drive current command. The torque-current conversion relationship refers to the fixed correspondence between the drive motor's output torque and the input drive current. This relationship is determined by the drive motor's rated parameters (such as the motor torque coefficient). The turntable control device converts the total driving torque into a drive current command that enables the drive motor to output a torque corresponding to the stress. This drive current command is then sent to the direct-drive turntable's drive module. The drive module controls the drive motor to output the corresponding current based on this command, thereby driving the direct-drive turntable to achieve precise and stable positioning control.

[0042] The embodiments of the present invention solve the technical problem that the positioning accuracy decreases in local areas and is accompanied by residual oscillations due to the adoption of a global unified control strategy, improve the positioning accuracy of the direct drive turntable in local angle ranges, and realize uniform positioning control of the direct drive turntable in the full circumference range.

[0043] Optionally, the processes of steps 201 to 204 include:

[0044] Step 201: Based on the full-circumference mechanical impedance distribution, the ratio trajectory of active power to reactive power is tracked to obtain the full-circumference energy efficiency slope sequence characterizing the change in electromechanical energy conversion efficiency.

[0045] Optionally, the full-circumference mechanical impedance distribution includes the mechanical impedance value corresponding to each angular position of the direct-drive turntable's full circumference. The mechanical impedance value includes amplitude and phase, where the phase parameter reflects the phase difference between the drive current and the mechanical response. For each angular node in the full-circumference mechanical impedance distribution, the turntable control device calculates the active and reactive power of the direct-drive turntable at that angular position. Active power refers to the power output by the direct-drive turntable's drive motor that can be converted into mechanical work, used to drive the turntable's rotation and overcome mechanical resistance. Reactive power refers to the power used to maintain the magnetic field of the direct-drive turntable's mechanical structure and is not directly converted into mechanical work; it is mainly related to the inductance and capacitance characteristics of the turntable's mechanical structure.

[0046] In the specific calculation process, based on the mechanical impedance amplitude and phase parameters of each angle node, combined with the corresponding drive current feedback data, active power and reactive power are calculated through energy conversion relationships: Active power is obtained by multiplying the effective value of the drive current, the mechanical impedance amplitude, and the cosine of the phase difference; that is, active power equals the effective value of the drive current multiplied by the mechanical impedance amplitude, and then multiplied by the cosine of the phase difference. Reactive power is obtained by multiplying the effective value of the drive current, the mechanical impedance amplitude, and the sine of the phase difference; that is, reactive power equals the effective value of the drive current multiplied by the mechanical impedance amplitude, and then multiplied by the sine of the phase difference.

[0047] After calculation, the active power and reactive power data corresponding to each angle node of the entire circle are obtained, forming a full-circle active power sequence and a full-circle reactive power sequence. The turntable control device performs synchronous processing on the full-circle active power sequence and the full-circle reactive power sequence to ensure accurate matching of the active power data and reactive power data corresponding to each angle node.

[0048] After synchronization, the turntable control device calculates the ratio of active power to reactive power for each angle node, obtaining a full-circumference energy efficiency ratio sequence. Each data point in the full-circumference energy efficiency ratio sequence corresponds to an angle position, reflecting the electromechanical energy conversion efficiency of the direct-drive turntable at that angle position. The larger the ratio, the higher the electromechanical energy conversion efficiency, meaning more electrical energy can be converted into mechanical work. The smaller the ratio, the lower the electromechanical energy conversion efficiency, meaning more electrical energy is consumed as reactive power.

[0049] The turntable control device performs trajectory tracking on the full-circumference energy efficiency ratio sequence. Trajectory tracking involves calculating the difference in energy efficiency ratio between adjacent angle nodes sequentially, in ascending order of angle. This difference is then divided by the angular interval between the two adjacent nodes to obtain the energy efficiency slope between them. This slope reflects the rate and direction of change in electromechanical energy conversion efficiency between two adjacent angles. A positive slope indicates that the energy efficiency ratio increases with increasing angle, and the electromechanical energy conversion efficiency gradually improves. A negative slope indicates that the energy efficiency ratio decreases with increasing angle, and the electromechanical energy conversion efficiency gradually decreases. This calculation is performed on all adjacent angle nodes along the full circumference to obtain the energy efficiency slope corresponding to each adjacent angle interval. All energy efficiency slopes are arranged in angular order to form a full-circumference energy efficiency slope sequence. This sequence characterizes the variation law of electromechanical energy conversion efficiency within the full circumference of the direct-drive turntable.

[0050] Step 202: Based on the full-circumference energy efficiency slope sequence, zero-crossing cross detection is performed to identify the angle position where the energy efficiency slope changes from positive to negative or from negative to positive, thereby obtaining energy efficiency polarity reversal candidate points. Based on the tooth cogging period base determined by the direct-drive turntable stator winding structure, the energy efficiency polarity reversal candidate points are periodically aligned and constrained. The candidate point with the smallest deviation from the position of an integer multiple of the tooth cogging period is retained to obtain the abrupt change reference point.

[0051] Optionally, each energy efficiency slope in the full-circumference energy efficiency slope sequence corresponds to an interval between two adjacent angle nodes, and they are arranged in ascending order of angle. The turntable control device performs zero-crossing cross-detection on the full-circumference energy efficiency slope sequence. Zero-crossing cross-detection refers to judging the polarity of each pair of adjacent energy efficiency slopes one by one, identifying the angle interval where the energy efficiency slope changes from positive to negative or from negative to positive. Within this interval, there is an angle position where the energy efficiency slope is zero. This angle position is the candidate point for energy efficiency polarity reversal. The angle position corresponding to the candidate point for energy efficiency polarity reversal is the key point where the direction of change in electromechanical energy conversion efficiency changes. The change in the direction of change in electromechanical energy conversion efficiency is essentially caused by a sudden change in the mechanical characteristics of the direct-drive turntable. Therefore, this candidate point can be used as a potential location for a sudden change in mechanical characteristics.

[0052] During the specific testing process, the turntable control device selects two adjacent energy efficiency slopes from the full-circumference energy efficiency slope sequence in ascending order of angle, and determines the polarity of the two energy efficiency slopes:

[0053] If the previous energy efficiency slope is positive and the next energy efficiency slope is negative, it means that there is a crossover point where the energy efficiency slope changes from positive to negative within the adjacent angle intervals corresponding to these two energy efficiency slopes. The angle position corresponding to this crossover point is a candidate point for energy efficiency polarity reversal.

[0054] If the preceding energy efficiency slope is negative and the following energy efficiency slope is positive, it indicates that within the adjacent angle intervals corresponding to these two energy efficiency slopes, there exists a crossover point where the energy efficiency slope changes from negative to positive. The angle position corresponding to this crossover point is a candidate point for energy efficiency polarity reversal. If two adjacent energy efficiency slopes have the same polarity, then there is no candidate point for energy efficiency polarity reversal. This detection is performed on all adjacent energy efficiency slopes in the full-circuit energy efficiency slope sequence, and the angle positions corresponding to all identified crossover points are collected to form candidate points for energy efficiency polarity reversal.

[0055] The turntable control device acquires the cogging cycle base number determined by the stator winding structure of the direct-drive turntable. The cogging cycle base number refers to the period length of the stator cogging of the direct-drive turntable drive motor, that is, the angular interval at which the relative positions of the stator cogging and the rotor magnetic poles repeat once during one rotation of the motor rotor. Its value is determined by the number of coggings in the stator winding and the number of rotor magnetic poles, and is an inherent structural parameter of the direct-drive turntable, which can be directly obtained from the design parameters of the direct-drive turntable. Using the cogging cycle base number as a reference, the turntable control device applies a period alignment constraint to each candidate point in the energy efficiency polarity reversal candidate points. The period alignment constraint determines the deviation of the angular position corresponding to each candidate point from the integer multiple of the cogging cycle base number, retains the candidate point with the smallest deviation, and eliminates candidate points with deviations exceeding a preset threshold, thus obtaining the abrupt change reference point.

[0056] In the specific constraint process, the positions that are integer multiples of the tooth groove cycle base are calculated. That is, starting from 0 degrees, 1, 2, ..., n times the tooth groove cycle base (n is a positive integer) are added sequentially to obtain several positions that are integer multiples of the tooth groove cycle. For each energy efficiency polarity reversal candidate point, the angle difference between the candidate point and each integer multiple position of the tooth groove cycle is calculated, and the smallest angle difference is selected as the deviation value of the candidate point. The deviation value of each candidate point is compared with a preset deviation threshold. Candidate points with deviation values ​​less than or equal to the preset deviation threshold are retained, and candidate points with deviation values ​​greater than the preset deviation threshold are eliminated. The remaining candidate points are the abrupt change reference points.

[0057] The preset deviation threshold is set according to the positioning accuracy requirements of the direct drive turntable, and is usually set between 0.5 degrees and 1 degree to ensure that the retained abrupt change reference point can accurately correspond to the position of the mechanical characteristic abrupt change caused by the tooth groove effect of the direct drive turntable.

[0058] Step 203: Based on the phase lag angle sequence in the full-circle mechanical impedance distribution, the phase-locked interval is extracted, and the continuous angle segment where the phase lag angle remains constant is identified to obtain the target phase plateau region.

[0059] Optionally, the turntable control device extracts the mechanical impedance phase parameters corresponding to each angle node from the full-circumference mechanical impedance distribution, and arranges the phase parameters corresponding to all angle nodes in ascending order of angle to form a full-circumference phase lag angle sequence.

[0060] The phase lag angle refers to the phase difference between the drive current and the mechanical response of the direct-drive turntable, i.e., the angle value corresponding to the time delay between the drive current signal and the mechanical vibration signal. Its magnitude reflects the damping and rigidity characteristics of the direct-drive turntable's mechanical structure. When the turntable's mechanical characteristics remain stable, the phase lag angle will remain within a fixed range. The turntable control device extracts the phase-locked interval from the full-circumference phase lag angle sequence. Phase-locked interval extraction refers to identifying continuous angle segments in the full-circumference phase lag angle sequence where the phase lag angle remains constant (or the change is within a preset small threshold range). These continuous angle segments are the phase-locked intervals. Since the phase lag angle is directly related to the turntable's mechanical characteristics, the direct-drive turntable's mechanical characteristics remain stable within the phase-locked interval.

[0061] The threshold for small phase changes is set according to the mechanical stability requirements of the direct drive turntable, and is usually set between 0.1 degrees and 0.5 degrees to determine whether the phase lag angle remains constant.

[0062] In the specific extraction process, following the increasing angle order, the phase lag angles corresponding to adjacent angle nodes are calculated one by one to obtain the phase difference between the two adjacent angle nodes. If the phase difference between two adjacent angle nodes is less than or equal to a preset small threshold, then the two angle nodes are determined to belong to the same phase-locked interval. If the phase difference between two adjacent angle nodes is greater than the preset small threshold, then the two angle nodes are determined to belong to different phase-locked intervals, with the former angle node being the termination node of the previous phase-locked interval and the latter angle node being the starting node of the next phase-locked interval.

[0063] Following the aforementioned rules, all angle nodes in the full-circular phase lag angle sequence are individually judged and divided to obtain several continuous phase-locked intervals. The turntable control device performs validity screening on each phase-locked interval, eliminating those with a length less than a preset length threshold (the preset length threshold is set according to the sampling interval, usually the angle length corresponding to 3 to 5 sampling intervals), thus avoiding false phase-locked intervals caused by sampling errors. The remaining phase-locked intervals after screening are the target phase platform areas, and each target phase platform area corresponds to a continuous angle segment with stable mechanical characteristics.

[0064] Step 204: Based on the mutation reference point and the target phase platform region, perform spatiotemporal overlap comparison to obtain each angle sub-region and its corresponding region boundary.

[0065] Optionally, the turntable control device performs a spatiotemporal overlap comparison based on the abrupt change reference point and the target phase platform region to obtain each angle sub-region and its corresponding region boundary, as detailed in steps 2041 to 2044.

[0066] The embodiments of the present invention achieve precise division of the full circumferential mechanical characteristics of the direct drive turntable, decomposing the originally uneven full circumferential mechanical characteristics into multiple local angle sub-regions with unified mechanical characteristics, accurately capturing the differential dynamic characteristics of mechanical structure gravity deformation, nonlinear changes in bearing friction torque, and motor cogging effect as position changes, thus realizing uniform positioning control of the direct drive turntable within the full circumference range.

[0067] Optionally, the process of steps 2041 to 2044 includes:

[0068] Step 2041: Based on the mutation reference point and the target phase plateau region, perform spatiotemporal overlap comparison to determine the angular coordinates of the polarity reversal position and the edge of the target phase plateau region, and obtain the target boundary anchor point.

[0069] Optionally, spatiotemporal overlap comparison refers to matching the angular position of the abrupt change reference point with the angular range of each target phase plateau region one by one, determining whether the abrupt change reference point falls within the range of the target phase plateau region or its edge, and then selecting the angular coordinates that meet the conditions as target boundary anchor points. Here, the target boundary anchor point refers to the angular coordinates that correspond to both the abrupt change location of mechanical characteristics and the edge of the stable region of mechanical characteristics, and can serve as a precise reference point for subsequent angular cutting.

[0070] During the specific comparison process, the angular range of each target phase plateau region is obtained, namely, the starting and ending angular coordinates of each target phase plateau region, thus clarifying the angular interval covered by each target phase plateau region. For each abrupt change reference point, it is determined whether the angular coordinates of the abrupt change reference point fall within the angular range of a certain target phase plateau region, or whether it coincides with the starting and ending angular coordinates of a certain target phase plateau region (i.e., it is at the edge of the target phase plateau region). If the angular coordinates of a certain abrupt change reference point fall within the angular range of a certain target phase plateau region, or coincide with the starting and ending angular coordinates of that target phase plateau region, then the angular coordinates corresponding to that abrupt change reference point are determined to be a candidate boundary anchor point.

[0071] If the angular coordinates of the mutation reference point do not fall within the angular range of any target phase platform area and do not coincide with the edge of any target phase platform area, the mutation reference point is determined to be an invalid reference point and is removed.

[0072] After performing the above judgment and screening on all mutation reference points one by one, all candidate boundary anchor points are collected. The candidate boundary anchor points are then deduplicated, and duplicate angle coordinates are removed (i.e., if multiple mutation reference points correspond to the same angle coordinate, only one is retained), thus obtaining the target boundary anchor points. Each angle coordinate in the target boundary anchor points simultaneously satisfies two conditions: first, it corresponds to the location of a mechanical characteristic mutation (originating from the mutation reference point); second, it is located at the edge of the target phase platform region where mechanical characteristics are stable.

[0073] Step 2042: Based on the target boundary anchor point, the full circumference angle is cut into angle segments, and the direction consistency of the impedance amplitude monotonicity in each angle segment is determined to obtain angle sub-units with a single increasing or decreasing trend.

[0074] Optionally, the turntable control device sorts all angular coordinates of the target boundary anchor points in ascending order of angle, covering a range from 0 to 360 degrees, ensuring that the anchor point order is consistent with the full-circumferential rotation direction of the direct-drive turntable. After sorting, the turntable control device uses two adjacent target boundary anchor points as cutting points to cut the full-circumferential angle range (0 to 360 degrees) of the direct-drive turntable. The angle interval between the last target boundary anchor point and the first target boundary anchor point is also cut, forming several continuous angle segments. The range of all angle segments covers the full-circumferential angle, and each angle segment has two target boundary anchor points as its starting and ending boundaries.

[0075] The turntable control device extracts the mechanical impedance amplitude corresponding to all angle nodes within each angle segment based on the full-circumference mechanical impedance distribution, forming an impedance amplitude subsequence for each angle segment. For each angle segment's impedance amplitude subsequence, a monotonicity direction consistency judgment is performed. The monotonicity direction consistency judgment determines whether the mechanical impedance amplitude within the angle segment exhibits a single increasing or decreasing trend, and whether this trend remains consistent within the angle segment without any reverse change.

[0076] In the specific discrimination process, the turntable control device calculates the difference in mechanical impedance amplitude between adjacent angle nodes in each angle segment, following an increasing angle order. If the impedance amplitude difference between all adjacent angle nodes in the segment is greater than or equal to zero, and at least one difference is greater than zero, then the impedance amplitude in the segment is determined to show a single increasing trend. If the impedance amplitude difference between all adjacent angle nodes in the segment is less than or equal to zero, and at least one difference is less than zero, then the impedance amplitude in the segment is determined to show a single decreasing trend. If there are both impedance amplitude differences greater than zero and impedance amplitude differences less than zero in the segment, then the impedance amplitude in the segment does not show a single increasing or decreasing trend and further segmentation is required.

[0077] For angle segments without a single increasing or decreasing trend, temporary anchor points are added within the segment. The addition rule is as follows: find the angle node within the segment where the impedance amplitude difference changes from positive to negative or from negative to positive, use the angle node as a temporary anchor point, and then use the temporary anchor point as the cutting point to cut the angle segment into two new angle segments. Repeat the above monotonicity discrimination process until the impedance amplitude in all angle segments shows a single increasing or decreasing trend. All angle segments with a single increasing or decreasing trend are angle sub-units. The mechanical impedance amplitude change trend in each angle sub-unit is consistent, reflecting the unified law of mechanical stiffness change in that sub-unit.

[0078] Step 2043: Based on the impedance increase / decrease direction jump relationship of adjacent angle sub-units, perform adjacent merging, merge angle sub-units with the same increase / decrease direction and continuous impedance amplitude transition, and obtain homogeneous force region.

[0079] Optionally, the turntable control device sorts all angle sub-units in ascending order of angle to ensure that the order of the sub-units is consistent with the order of the angles of the entire circle, and they are connected sequentially to cover the entire circumference.

[0080] After the sorting is completed, the turntable control device analyzes the impedance increase / decrease direction jump relationship of two adjacent angle sub-units one by one. The impedance increase / decrease direction jump relationship refers to whether the impedance amplitude increase / decrease direction of two adjacent angle sub-units has changed, that is, whether the increase / decrease direction of the previous sub-unit is consistent with the increase / decrease direction of the next sub-unit. If they are inconsistent, it is considered that a jump has occurred; if they are consistent, it is considered that there is no jump.

[0081] During the specific analysis process, the turntable control device records the direction of impedance increase or decrease (increasing or decreasing) for each angle sub-unit. Then, it selects two adjacent angle sub-units in sequence and compares their directions of increase or decrease:

[0082] If the impedance increase / decrease directions of two adjacent angle sub-units are the same, the turntable control device further determines whether the impedance amplitude between the two sub-units is continuously transitioned. Continuous impedance amplitude transition means that the difference between the mechanical impedance amplitude corresponding to the termination angle node of the previous sub-unit and the mechanical impedance amplitude corresponding to the starting angle node of the next sub-unit is less than or equal to the preset continuous threshold.

[0083] The preset continuous threshold is set according to the mechanical characteristic consistency requirements of the direct drive turntable. It is usually set to between 1% and 3% of the maximum value of the full circumference mechanical impedance amplitude to ensure that the mechanical characteristics of the two sub-units can be smoothly connected without obvious abrupt changes.

[0084] If the impedance of two adjacent angle sub-units increases or decreases in the same direction and the impedance amplitude transitions continuously, then these two angle sub-units are merged to form a new angle unit. The starting angle of the new angle unit is the starting angle of the previous sub-unit, and the ending angle is the ending angle of the next sub-unit. The direction of impedance increase or decrease is consistent with the original two sub-units.

[0085] If the impedance increase / decrease directions of two adjacent angle sub-units are different, or if the increase / decrease directions are the same but the impedance amplitude transitions discontinuously, they are not merged, and two independent angle sub-units are retained. The turntable control device performs judgment and merging operations on all adjacent angle sub-units one by one according to the above rules, until all adjacent angle sub-units can no longer be merged. Each resulting independent angle unit is a homogeneous force region. Within each homogeneous force region, the impedance amplitude increases / decreases in the same direction, and the impedance amplitude transitions continuously, reflecting the uniformity of the direct-drive turntable's mechanical characteristics (rigidity, damping, etc.) within that region.

[0086] Step 2044: Align the electrical commutation points based on the boundary angle coordinates of the homogeneous force region to update the region boundary to the angle position corresponding to the most recent electrical commutation moment, thereby obtaining each angle sub-region and its corresponding region boundary.

[0087] Optionally, the turntable control device extracts the boundary angle coordinates of each homogeneous force region, i.e., the starting and ending angle coordinates of each homogeneous force region. The boundary angle coordinates are the preliminary region boundaries. The turntable control device obtains the angle position corresponding to the electrical commutation point of the direct-drive turntable motor. The electrical commutation point refers to the angle position corresponding to the moment when the stator winding current of the direct-drive turntable motor commutates. It is an inherent position point during the operation of the drive motor. Its angle coordinates are determined by parameters such as the winding structure and number of magnetic poles of the drive motor. It is collected through the electrical detection module of the turntable control device or directly obtained through a preset electrical commutation point parameter table. The angle position corresponding to the electrical commutation point is a key node for the stable change of the output torque of the drive motor. Aligning the region boundary with the electrical commutation point ensures that the control switching at the region boundary is synchronized with the motor torque output switching, avoiding positioning errors and vibrations caused by the asynchrony between control switching and electrical commutation.

[0088] During the specific alignment process, the turntable control device searches for the angle position corresponding to the nearest electrical commutation point for the starting boundary angle coordinates of each homogeneous force region, and calculates the angle difference between the starting boundary angle coordinates and the angle position of the nearest electrical commutation point.

[0089] Simultaneously, for the termination boundary angle coordinates of each homogeneous force region, the angle position corresponding to its nearest electrical commutation point is searched, and the angle difference between the termination boundary angle coordinates and the angle position of the nearest electrical commutation point is calculated. The starting boundary angle coordinates of each homogeneous force region are updated to the angle position of its nearest electrical commutation point, and the termination boundary angle coordinates are updated to the angle position of its nearest electrical commutation point, thus completing the electrical commutation point alignment.

[0090] After alignment, the turntable control device performs boundary verification on all updated homogeneous force regions. Verification includes: whether the boundary angle coordinates of all regions are within the range of 0 to 360 degrees; whether the boundaries of adjacent regions overlap (to avoid overlap); and whether all regions completely cover the entire circumferential angle range (to avoid gaps). If there are cases where boundaries exceed the range, adjacent regions overlap, or gaps exist, the boundary angle coordinates are fine-tuned. The fine-tuning amplitude does not exceed a preset fine-tuning threshold (the preset fine-tuning threshold does not exceed 0.5 degrees to ensure that the homogeneous force characteristics within the region are not affected), until all regions meet the verification requirements. Each homogeneous force region after electrical commutation point alignment and boundary verification is an angle sub-region. The updated start and end boundary angle coordinates corresponding to each angle sub-region are the region boundaries corresponding to that angle sub-region.

[0091] This invention achieves synchronization between the region boundary and the motor torque output switching, avoiding positioning errors and vibrations caused by asynchronous control switching and electrical commutation. It obtains an angle sub-region and its corresponding region boundary that accurately adapts to the motor's operating characteristics, ensuring uniform mechanical characteristics within each angle sub-region. This guarantees the accuracy of direct-drive turntable control and achieves uniform positioning control of the direct-drive turntable across the entire circumference.

[0092] Optionally, the processes of steps 301 to 304 include:

[0093] Step 301: Based on the equivalent mechanical stiffness value corresponding to each angular sub-region and the trajectory of the preset target position, construct the potential energy gradient to obtain the position potential energy vector field characterizing the direction of the required restoring torque of the rotor at each angular position.

[0094] Optionally, for each angle sub-region, the turntable control device extracts the mechanical impedance amplitudes corresponding to all angle nodes within that region. It then calculates the equivalent mechanical stiffness value of that angle sub-region using an arithmetic mean method. The equivalent mechanical stiffness value refers to a stiffness parameter that represents the overall rigidity characteristics of the angle sub-region. The calculation process is as follows: the mechanical impedance amplitudes of all angle nodes within the angle sub-region are added together to obtain a total impedance amplitude. This total impedance amplitude is then divided by the number of angle nodes within the region. The average value obtained is the equivalent mechanical stiffness value of the angle sub-region. A larger value indicates stronger mechanical stiffness and greater resistance to deformation in the angle sub-region. A smaller value indicates weaker mechanical stiffness and a greater susceptibility to elastic deformation in the angle sub-region.

[0095] The turntable control device acquires the trajectory of the preset target position. This trajectory refers to a series of target angular positions that the direct-drive turntable needs to reach according to a preset pattern. This trajectory is sent from the upper control system to the turntable control device, covering the target running path within the entire circumference of the direct-drive turntable, and clearly defining the preset target angular position at each moment. Based on the equivalent mechanical stiffness value of each angular sub-region and combined with the trajectory of the preset target position, a potential energy gradient is constructed. The potential energy gradient is a physical quantity that characterizes the rate and direction of potential energy change of the direct-drive turntable rotor at different angular positions. It reflects the potential energy change pattern generated when the rotor deviates from the preset target position, thereby determining the direction of the restoring torque required for the rotor to return to the preset target position.

[0096] In the specific construction process, the turntable control device uses the equivalent mechanical stiffness value of each angle sub-region as the intensity coefficient of the potential energy gradient, and the target angle position in the trajectory of the preset target position corresponding to that region as the point of lowest potential energy (i.e., the position with the minimum potential energy). It calculates the angular deviation between each angle node in that region and its corresponding target angle position, and multiplies the square of the angular deviation by the equivalent mechanical stiffness value to obtain the potential energy value corresponding to that angle node. Following the increasing angle order, the potential energy values ​​of adjacent angle nodes in that region are calculated one by one to obtain the potential energy difference between adjacent angle nodes. This potential energy difference is then divided by the angular interval between the two adjacent angle nodes to obtain the rate of change of potential energy. This rate of change of potential energy is the magnitude of the potential energy gradient, and the direction of the potential energy gradient is from the angle node with the higher potential energy value to the angle node with the lower potential energy value (i.e., the direction towards the preset target position).

[0097] The turntable control device constructs the aforementioned potential energy gradient for each of the angular sub-regions, and correlates the magnitude and direction of the potential energy gradient corresponding to all angular nodes within each angular sub-region to form a position potential energy vector field covering the entire circumference of the direct-drive turntable. The position potential energy vector field refers to the magnitude and direction of the potential energy gradient corresponding to each angular position within the entire circumference of the direct-drive turntable, clearly characterizing the direction of the restoring torque required by the rotor at each angular position.

[0098] Step 302: Based on the position potential energy vector field and the current angular position of the direct drive turntable, analyze the gradient descent direction to obtain the direction of the main driving torque for position tracking control.

[0099] Optionally, the turntable control device acquires the current angular position of the direct-drive turntable. The current angular position is detected in real time by the position detection module (such as an encoder) of the turntable control device, which can accurately reflect the current angular coordinates of the direct-drive turntable rotor. Based on the current angular position, the turntable control device searches for the potential energy gradient information corresponding to that angular position in the position potential energy vector field, including the magnitude and direction of the potential energy gradient, to clarify the potential energy change pattern at the current angular position.

[0100] The turntable control device analyzes the potential energy gradient direction corresponding to the current angular position to determine the gradient descent direction. The gradient descent direction refers to the direction in which the potential energy value gradually decreases and points towards the point of lowest potential energy (the preset target position), which is also the direction in which the rotor can return to the preset target position with minimal potential energy consumption. Specifically, the analysis determines the potential energy gradient direction corresponding to the current angular position: if the potential energy value at the current angular position is higher than the potential energy value at the preset target position (i.e., the current angular position deviates from the preset target position), then the gradient descent direction is consistent with the direction of the potential energy gradient, pointing towards the preset target position. If the current angular position coincides with the preset target position (i.e., there is no angular deviation), then the gradient descent direction is zero, and no restoring torque is required.

[0101] The turntable control device, based on the rotation direction (clockwise or counterclockwise) of the direct-drive turntable, converts the gradient descent direction into the direction of the active torque for position tracking control. The active torque direction refers to the direction of the torque driving the direct-drive turntable rotor towards the preset target position, and it matches the gradient descent direction. Specifically, during the conversion process, if the gradient descent direction is clockwise (i.e., the current angular position is counterclockwise from the preset target position), the active torque direction is set clockwise, driving the rotor to rotate clockwise and approach the preset target position. If the gradient descent direction is counterclockwise (i.e., the current angular position is clockwise from the preset target position), the active torque direction is set counterclockwise, driving the rotor to rotate counterclockwise and approach the preset target position. If the gradient descent direction is zero, the active torque direction is zero, and no active tracking torque is output.

[0102] Step 303: Based on the equivalent mechanical damping value and the real-time angular velocity of the rotor corresponding to each angular sub-region, the power flow direction is determined to obtain the power exchange direction required for damping control.

[0103] Optionally, for each angle sub-region, the turntable control device extracts the mechanical impedance phase parameters corresponding to all angle nodes within that region, and calculates the equivalent mechanical damping value for that angle sub-region by combining the mechanical impedance amplitude. The equivalent mechanical damping value refers to the damping parameter that represents the overall damping characteristics of that angle sub-region, and its calculation process is as follows:

[0104] Multiply the mechanical impedance amplitude of all angular nodes within the angular sub-region by the sine of the corresponding phase difference to obtain the damping component of each angular node. Then, sum the damping components of all angular nodes to obtain the total damping components. Finally, divide the total damping components by the number of angular nodes in the region. The average value obtained is the equivalent mechanical damping value of the angular sub-region. The larger the value, the better the damping effect of the angular sub-region and the stronger its ability to suppress vibration. The smaller the value, the worse the damping effect of the angular sub-region and the more prone it is to elastic vibration.

[0105] The turntable control device collects the real-time angular velocity of the direct-drive turntable rotor. Real-time angular velocity refers to the angle of rotation of the rotor per unit time, which is detected in real-time by the speed detection module of the turntable control device. It accurately reflects the magnitude and direction (clockwise or counterclockwise) of the rotor's current movement speed. For each angular sub-region, the turntable control device, combining the equivalent mechanical damping value of that region and the rotor's real-time angular velocity, performs power flow direction determination. Power flow direction determination refers to determining the direction of power exchange between the direct-drive turntable mechanical system and the drive motor, clarifying the power input or output direction required for damping control, and determining the direction of the damping torque.

[0106] In the specific judgment process, the turntable control device calculates the product of the rotor's real-time angular velocity and the equivalent mechanical damping value to obtain the magnitude of the damping power, and at the same time determines the rotor's motion state:

[0107] If the rotor is in a deceleration state (i.e., the absolute value of the real-time angular velocity gradually decreases), it indicates that the mechanical system is consuming kinetic energy. At this time, the damping power is positive, and the power flow direction is the mechanical system feeding back power to the drive motor. The power exchange direction required for damping control is for the drive motor to absorb the feedback power from the mechanical system. By consuming the feedback power, the damping effect is enhanced, and rotor vibration is suppressed.

[0108] If the rotor is accelerating (i.e., the absolute value of the real-time angular velocity gradually increases), it indicates that the drive motor is inputting power into the mechanical system. At this time, the damping power is negative, and the power flow direction is that the drive motor inputs power into the mechanical system. The power exchange direction required for damping control is that the drive motor outputs damping power into the mechanical system. By supplementing the damping power, the vibration of the rotor caused by acceleration is suppressed. If the rotor is in a constant speed state (i.e., the absolute value of the real-time angular velocity remains unchanged), it indicates that the kinetic energy of the mechanical system remains stable. At this time, the damping power is zero, the power exchange direction is zero, and no additional input or absorption of power is required. The vibration suppression state is maintained solely by the equivalent mechanical damping value.

[0109] Step 304: Path allocation is performed based on the active torque direction and power exchange direction to obtain the position tracking control path and damping control path corresponding to each angle sub-region.

[0110] Optionally, the turntable control device performs path allocation based on the active torque direction and power exchange direction corresponding to each angle sub-region, to obtain the position tracking control path and damping control path corresponding to each angle sub-region, as described in steps 3041 to 3044.

[0111] The embodiments of the present invention accurately adapt to the homogeneous force characteristics of each angular sub-region, effectively avoiding the drawbacks of mixing "fast tracking" and "vibration suppression", so that each angular sub-region can obtain a control path adapted to its own mechanical characteristics, ensuring that high rigidity areas have sufficient tracking driving force and easily vibrating areas have effective damping suppression capabilities, thus realizing uniform positioning control of the direct drive turntable within the entire circumference.

[0112] Optionally, the processes of steps 3041 to 3044 include:

[0113] Step 3041: Based on the power exchange direction and the winding resistance parameters of the direct drive turntable, the Joule heat loss boundary is defined to obtain the upper limit of the current amplitude without exceeding the motor temperature rise limit. Based on the cogging torque distribution characteristics and the active torque direction of the direct drive turntable, ripple cancellation vector synthesis is performed to obtain the ripple suppression component.

[0114] Optionally, the turntable control device acquires the winding resistance parameters of the direct-drive turntable motor. The winding resistance parameter refers to the resistance value of the stator winding of the direct-drive turntable motor, which is an inherent electrical parameter of the motor and can be directly obtained from the design parameters of the direct-drive turntable. Its magnitude directly affects the Joule heat loss generated when the drive current flows through the winding. Joule heat loss refers to the energy loss generated when electrical energy is converted into heat energy when the drive current flows through the winding resistance. This loss causes the motor temperature to rise. If the temperature exceeds the motor temperature rise limit, it will damage the motor windings, affecting the normal operation and service life of the drive motor. Therefore, it is necessary to limit the Joule heat loss by determining the upper limit of the current amplitude. Specifically, in the boundary limiting process, the turntable control device acquires the preset temperature rise limit of the direct-drive turntable motor. The preset temperature rise limit refers to the difference between the highest allowable temperature of the drive motor during normal operation and the ambient temperature, determined by the rated parameters of the drive motor, and is usually set between 40 degrees Celsius and 60 degrees Celsius.

[0115] The turntable control device calculates the maximum allowable Joule heat loss of the drive motor based on the winding resistance parameters, preset temperature rise limits, and the heat dissipation coefficient of the drive motor (the heat dissipation coefficient is the ratio of the heat dissipated by the drive motor per unit time to the temperature difference, which is a known fixed parameter). The calculation process is as follows: the maximum Joule heat loss is equal to the product of the heat dissipation coefficient and the preset temperature rise limit, ensuring that the generated Joule heat loss can be dissipated in time through the heat dissipation system, preventing the motor temperature from exceeding the limit. Based on the maximum Joule heat loss and winding resistance parameters, the turntable control device calculates the upper limit of the current amplitude that does not exceed the motor temperature rise limit. The calculation process is as follows: the square of the upper limit of the current amplitude is equal to the maximum Joule heat loss divided by the winding resistance parameter, and then the square root of the calculation result is taken. The resulting value is the upper limit of the current amplitude, which is the maximum allowable drive current amplitude of the drive motor. The amplitude of all subsequent current vectors must be controlled within this upper limit.

[0116] The turntable control device acquires the cogging torque distribution characteristics of the direct-drive turntable. The cogging torque distribution characteristics refer to the distribution law of the torque generated by the electromagnetic attraction between the stator slots and the rotor magnetic poles along the full circumference during the rotation of the rotor of the direct-drive turntable drive motor. This distribution characteristic is determined by the number of stator slots, the number of rotor magnetic poles, and the winding structure. It can be obtained through the design parameters of the direct-drive turntable or through data collected in the early stage of the experiment. The cogging torque will cause ripple in the drive current, which will affect the positioning accuracy and dynamic stability of the turntable. Therefore, it is necessary to synthesize ripple suppression components to cancel out the ripple.

[0117] The turntable control device synthesizes ripple cancellation vectors based on the direction of the active torque corresponding to each angular sub-region and the distribution characteristics of the cogging torque, thus obtaining ripple suppression components. Specifically, for each angular sub-region, the amplitude and direction of the cogging torque within that region are extracted. The direction of the ripple suppression component is determined based on the direction of the cogging torque, ensuring that the direction of the ripple suppression component is opposite to the direction of the cogging torque, thereby effectively canceling the ripple generated by the cogging torque. The amplitude of the ripple suppression component is determined based on the amplitude of the cogging torque and the intensity of the active torque direction, ensuring that the amplitude of the ripple suppression component matches the amplitude of the cogging torque and adapts to the requirements of the active torque direction. This ensures that the ripple suppression component effectively cancels ripple without affecting the normal output of the active torque, resulting in the ripple suppression component corresponding to each angular sub-region.

[0118] Step 3042: Limit the ripple suppression component within the current circle that is allowed by the upper limit of the current amplitude to obtain the current vector after amplitude constraint.

[0119] Optionally, the turntable control device performs amplitude constraint processing based on the ripple suppression component and the upper limit of current amplitude corresponding to each angle sub-region. The current circle refers to the circular area formed with the origin of the stator coordinate system of the drive motor as the center and the upper limit of current amplitude as the radius. All current vector amplitudes within this area do not exceed the upper limit of current amplitude, which can ensure that the Joule heat loss of the drive motor does not exceed the limit and avoid excessive motor temperature rise.

[0120] During the specific constraint process, the turntable control device calculates the amplitude of the ripple suppression component corresponding to each angle sub-region and compares the calculated amplitude with the upper limit of the current amplitude. If the amplitude of the ripple suppression component is less than or equal to the upper limit of the current amplitude, it means that the ripple suppression component is within the current circle and no adjustment is needed; the ripple suppression component is directly used as the current vector after amplitude constraint. If the amplitude of the ripple suppression component is greater than the upper limit of the current amplitude, it means that the ripple suppression component is outside the current circle and amplitude adjustment is required. The adjustment process is as follows: keeping the direction of the ripple suppression component unchanged, its amplitude is proportionally reduced to the upper limit of the current amplitude. The reduction ratio is the ratio of the upper limit of the current amplitude to the original amplitude of the ripple suppression component. This ensures that the amplitude of the adjusted current vector is equal to the upper limit of the current amplitude and its direction is consistent with the original direction of the ripple suppression component, thus satisfying the motor temperature rise limit requirements while maximizing the ripple suppression effect.

[0121] After applying the above amplitude constraint processing to the ripple suppression components corresponding to all angle sub-regions, the amplitude-constrained current vector corresponding to each angle sub-region is obtained.

[0122] Step 3043: Based on the current vector and power exchange direction of adjacent angle sub-regions at the region boundary, perform vector endpoint continuity comparison to identify the angular deviation of the current vector direction on both sides of the boundary.

[0123] Optionally, the turntable control device performs vector endpoint continuity comparison based on the current vectors and power exchange directions of adjacent angular sub-regions at the region boundaries. Vector endpoint continuity comparison involves extracting the current vectors of two adjacent angular sub-regions at their common boundary, comparing the endpoint positions and directions of the two current vectors to determine if they can smoothly connect, and identifying the angular deviation of the current vector directions on both sides of the boundary. Excessive angular deviation will cause a sudden change in control current when the turntable crosses the region boundary, resulting in vibration and affecting positioning accuracy and dynamic stability. Specifically, during the comparison process, all adjacent angular sub-region pairs are identified. For each pair of adjacent angular sub-regions, their common boundary is found, and two current vectors at this common boundary are extracted: the current vector of the preceding angular sub-region at the boundary (boundary exit current vector) and the current vector of the following angular sub-region at the boundary (boundary inlet current vector). The power exchange directions corresponding to the two adjacent angular sub-regions are then called to ensure that the directions of the two current vectors match the power exchange directions of their respective regions, avoiding vector direction anomalies caused by conflicts in power exchange directions.

[0124] The turntable control device calculates the angle between the boundary outlet current vector and the boundary inlet current vector. This angle is the angular deviation between the directions of the current vectors on both sides of the boundary. The calculation process is as follows: taking the origin of the two current vectors as the origin, determine the direction angles of the two current vectors in the stator coordinate system. The difference between the two direction angles is the angular deviation. The angular deviation ranges from 0 degrees to 180 degrees. The smaller the angular deviation, the closer the directions of the two current vectors are, and the better the continuity. The larger the angular deviation, the greater the difference between the directions of the two current vectors, the worse the continuity, and the more likely it is to cause control abrupt changes. The turntable control device performs the above comparison on the common boundary of all adjacent angle sub-regions one by one, and records the angular deviation at each boundary.

[0125] Step 3044: Based on the included angle deviation, generate the shortest circular arc trajectory of the current vectors on both sides of the connecting boundary in the vector space, and obtain the position tracking control path and damping control path within the full circumference range.

[0126] Optionally, based on the included angle deviation at the boundary of each region, the turntable control device generates the shortest circular arc trajectory connecting the current vectors on both sides of the boundary in the vector space for the common boundary of each adjacent angle sub-region. The vector space refers to the two-dimensional space with the horizontal and vertical axes of the drive motor stator coordinate system as coordinate axes, used to characterize the direction and magnitude of the current vector. The shortest circular arc trajectory refers to the arc with the smallest radius connecting the endpoints of the two current vectors, which can realize the smooth transition of the two current vectors and avoid sudden changes in the control current.

[0127] In the specific generation process, for the two current vectors at each boundary (boundary outlet current vector and boundary inlet current vector), an arc is generated with the starting point of the two current vectors (the origin of the stator coordinate system) as the center and the upper limit of the current amplitude as the radius. The arc is the shortest arc trajectory connecting the two current vectors. Since both current vectors are subject to amplitude constraints, with the amplitude equal to or less than the upper limit of the current amplitude, the arc with the origin as the center can ensure that the amplitude of all current vectors on the trajectory does not exceed the upper limit of the current amplitude. At the same time, the shortest arc can shorten the transition path to the maximum extent and reduce control delay.

[0128] If the angular deviation between the current vector directions on both sides of the boundary is 0 degrees, it means that the two current vector directions are completely consistent. In this case, there is no need to generate an arc trajectory; the two current vectors can be directly connected by a straight line. If the angular deviation is greater than 0 degrees, the corresponding shortest arc trajectory is generated as the transition trajectory at the boundary of two adjacent angular sub-regions. The turntable control device connects the current vectors in each angular sub-region in angular order, and then connects the shortest arc trajectory at the boundary of adjacent regions with the current vector trajectories of the two sides, forming a complete current vector trajectory covering the entire circumference.

[0129] The turntable control device integrates the portion of the current vector trajectory corresponding to the direction of the active torque into a position tracking control path, which is used to control the drive motor to output the corresponding active torque, thereby achieving precise tracking of the rotor to the preset target position. It also integrates the portion of the current vector trajectory corresponding to the direction of power exchange into a damping control path, which is used to control the drive motor to output the corresponding damping power, thereby effectively suppressing rotor vibration. This results in position tracking control paths and damping control paths corresponding to each angular sub-region.

[0130] Embodiments of the present invention.

[0131] Optionally, steps 305 to 308 include:

[0132] Step 305: Perform curvature change rate analysis based on the angle sequence of the position tracking control path to obtain the curvature change rate of the position tracking path, and perform fluctuation range analysis based on the current amplitude sequence of the damping control path to obtain the vibration amplitude change rate of the damping control path.

[0133] Optionally, the turntable control device extracts the angle sequence corresponding to the position tracking control path. This angle sequence is a set formed by arranging all continuous angle nodes on the position tracking control path in ascending order of angle. Each angle node corresponds to an actual angular position of the direct-drive turntable and is one-to-one with the current vector of the position tracking control path. Based on this angle sequence, the turntable control device performs curvature change rate analysis. The curvature change rate refers to the rate at which the curvature of the position tracking control path changes with the angle. Curvature refers to the degree of bending at a certain point on the path. The greater the curvature, the more obvious the bending of the path at that angular position.

[0134] In the specific analysis process, the turntable control device calculates the curvature of each pair of adjacent angle nodes in the angle sequence in ascending order. It calculates the line segment length between any two adjacent angle nodes, and then calculates the radius of the arc formed by the three adjacent angle nodes. The reciprocal of this arc radius is the curvature value corresponding to the intermediate angle node. The difference between the curvature values ​​of any two adjacent intermediate angle nodes is calculated, and this difference is divided by the angular interval between the two intermediate angle nodes to obtain the rate of change between the two adjacent curvature values. This rate of change is the curvature change rate of the position tracking path. This calculation is performed on all three adjacent angle nodes in the angle sequence to obtain the curvature change rate of the position tracking path for each intermediate angle node, forming a curvature change rate sequence covering the position tracking control path.

[0135] The turntable control device extracts the current amplitude sequence corresponding to the damping control path. This current amplitude sequence is a set formed by arranging the amplitudes of all continuous current vectors on the damping control path in ascending order of angle. Each current amplitude corresponds to an actual angular position of the direct-drive turntable, reflecting the fluctuation of the current amplitude on the damping control path. Based on this current amplitude sequence, the turntable control device performs fluctuation range analysis. The fluctuation range refers to the difference between the maximum and minimum current amplitudes within a certain angular interval, and the vibration amplitude change rate refers to the rate at which the fluctuation range changes with the angle, reflecting the changing trend of the turntable vibration degree.

[0136] In the specific analysis process, the turntable control device sets the fluctuation analysis interval. The length of the fluctuation analysis interval is set according to the sampling interval of the direct-drive turntable, typically the angle length corresponding to 3 to 5 sampling intervals. Following an increasing angle sequence, the current amplitude sequence is divided into fluctuation analysis intervals. Each fluctuation analysis interval contains several consecutive current amplitude data points, and adjacent fluctuation analysis intervals overlap, with the overlap length being half the length of the fluctuation analysis interval. For each fluctuation analysis interval, all current amplitude data within that interval are extracted, and the maximum and minimum values ​​are identified. The difference between the maximum and minimum values ​​is calculated to obtain the fluctuation range corresponding to that fluctuation analysis interval. The difference between the fluctuation ranges corresponding to two adjacent fluctuation analysis intervals is calculated, and this difference is divided by the difference in the starting angles of the two fluctuation analysis intervals to obtain the rate of change between the two adjacent fluctuation ranges. This rate of change is the vibration amplitude change rate of the damping control path. This calculation is performed for all fluctuation analysis intervals one by one to obtain the vibration amplitude change rate corresponding to each fluctuation analysis interval, forming a vibration amplitude change rate sequence covering the damping control path.

[0137] Step 306: Construct a two-dimensional feature space based on the curvature change rate of the position tracking path and the vibration amplitude change rate of the damping control path to obtain a joint feature map of the two change rates.

[0138] Optionally, the turntable control device constructs a two-dimensional feature space based on the position tracking path curvature change rate sequence and the damping control path vibration amplitude change rate sequence. The two-dimensional feature space refers to a two-dimensional coordinate space formed by the position tracking path curvature change rate on the horizontal axis and the damping control path vibration amplitude change rate on the vertical axis. Each coordinate point in this space corresponds to an actual angular position of the direct-drive turntable. The horizontal axis coordinate of the coordinate point is the position tracking path curvature change rate corresponding to that angular position, and the vertical axis coordinate is the damping control path vibration amplitude change rate corresponding to that angular position.

[0139] In the specific construction process, the turntable control device performs synchronous alignment processing on the two rate of change sequences to ensure that each data in the two sequences corresponds to the same angular position of the direct drive turntable. The basis for synchronous alignment is the angular nodes corresponding to the two sequences. The data corresponding to the same angular position in the position tracking path curvature rate of change sequence and the vibration amplitude rate of change sequence are matched one by one to form several sets of dual rate of change data pairs.

[0140] The turntable control device inputs each pair of dual-rate-change data as a coordinate point into a two-dimensional feature space. The rate of change of curvature of the position tracking path in each data pair is used as the horizontal axis coordinate value of that point, and the rate of change of vibration amplitude of the damping control path is used as the vertical axis coordinate value. All coordinate points are plotted sequentially in the two-dimensional feature space according to increasing angles, and adjacent coordinate points are connected sequentially with smooth line segments to form a continuous trajectory line.

[0141] The turntable control device performs feature annotation on the completed two-dimensional feature space. The annotation content includes the direct drive turntable angle position corresponding to each coordinate point, the trend of the trajectory line, and the coordinate points where the rate of curvature change or the rate of vibration amplitude change in the trajectory line reaches an extreme value. The extreme point corresponds to the angle position where the turntable position tracking is most difficult or the vibration is most intense, forming a joint feature map of the two rates of change.

[0142] Step 307: Based on the slope of the two rate of change components in the dual rate of change joint feature map, perform trend consistency comparison analysis to obtain the trend determination result.

[0143] Optionally, the turntable control device extracts the slopes of the rate of change of curvature of the position tracking path and the rate of change of vibration amplitude of the damping control path from the dual-rate-change joint feature map. The slope refers to the degree of inclination of the rate of change as the angle changes; a positive slope indicates that the rate of change increases with increasing angle, while a negative slope indicates that the rate of change decreases with increasing angle. The absolute value of the slope represents the rate of increase or decrease of the rate of change. Trend consistency comparison analysis compares the polarity and rate of change of the slopes of the two rate of change components to determine whether their trends are consistent. Specifically, in the comparison analysis, the turntable control device calculates the slopes of adjacent coordinate points in the dual-rate-change joint feature map one by one, in ascending order of angle, calculating the slope of the rate of change of curvature of the position tracking path and the slope of the rate of change of vibration amplitude of the damping control path between each adjacent coordinate point. By comparing the polarity of the two slopes corresponding to the same set of adjacent coordinate points, if both slopes are positive or both are negative, the trends are determined to be in the same direction. If one slope is positive and the other is negative, the trends are determined to be in opposite directions.

[0144] The turntable control device calculates the absolute difference between two changing slopes. If the absolute difference is less than or equal to a preset slope difference threshold (which is typically between 0.01 and 0.05, set according to the control accuracy requirements of the direct-drive turntable), the two slopes are considered to have matching rates of change. If the absolute difference is greater than the preset slope difference threshold, the two slopes are considered to have mismatched rates of change. This comparison is performed on all adjacent coordinate points, comparing the two changing slopes one by one. Combining the correlation between the changing trends and the matching rates of change, a trend determination result is formed. The trend determination result is divided into three categories: first, the changing trends are in the same direction and the changing rates match; second, the changing trends are in the same direction but the changing rates do not match; and third, the changing trends are in opposite directions (regardless of whether the changing rates match).

[0145] Step 308: Based on the trend determination result, the current vectors corresponding to the position tracking control path and the damping control path are combined and analyzed at the current angle to obtain the composite control direction for the current angle.

[0146] Optionally, based on the trend determination result, the current vectors corresponding to the position tracking control path and the damping control path are combined and analyzed at the current angle to obtain the composite control direction for the current angle.

[0147] The embodiments of the present invention achieve precise generation of composite control directions, improve the control adaptability of direct drive turntables at different angular positions, optimize positioning accuracy, suppress vibration interference during position tracking, ensure the smooth operation of the turntable, and improve the response speed and adaptability of the control system.

[0148] Optionally, the process of steps 3081 to 3084 includes:

[0149] Step 3081: Based on the trend determination result, determine the control dominance and obtain the control dominance direction for the current angle.

[0150] Optionally, the trend determination results are divided into three categories: first, the changing trends are in the same direction and the rates of change match; second, the changing trends are in the same direction but the rates of change do not match; and third, the changing trends are in opposite directions (regardless of whether the rates of change match). The determination of control dominance refers to identifying, based on different trend determination results, which control requirement—position tracking control or damping control—has a higher priority at the current angle, thereby determining the dominant control direction. The dominant control direction refers to the control direction that needs to be emphasized at the current angle, and is divided into two types: position tracking dominant direction and damping control dominant direction. This ensures that the synthesized composite control direction can adapt to the operating state at the current angle, avoiding control imbalance.

[0151] A preset control dominance judgment threshold is set, which includes a slope difference threshold supplement and a trend weight coefficient.

[0152] The slope difference threshold supplement is consistent with the preset slope difference threshold in step 307, and is usually between 0.01 and 0.05. The trend weight coefficient quantifies the priority of the two controls under different trend judgment results. The position tracking trend weight coefficient and the damping control trend weight coefficient are both preset to between 0 and 1, and the sum is 1.

[0153] If the trend determination result shows that the changing trends are in the same direction and the rates of change are matched, it indicates that the change in position tracking difficulty and the change in turntable vibration intensity are synchronous and at the same rate at the current angle. In this case, the needs of position tracking control and damping control are balanced. The turntable control device sets both the position tracking trend weight coefficient and the damping control trend weight coefficient to 0.5, determining that the dominant control direction is that position tracking and damping control are jointly dominant, with no single priority. If the trend determination result shows that the changing trends are in the same direction but the rates of change are mismatched, the turntable control device calculates the ratio of the absolute difference between the two slopes to the slope difference threshold supplementary item. If this ratio is greater than 1 and less than or equal to 2, it indicates that the rate of change of position tracking difficulty is higher than the rate of change of vibration intensity. The position tracking trend weight coefficient is set to 0.6 and the damping control trend weight coefficient is set to 0.4, determining that the dominant control direction is position tracking dominant. If this ratio is greater than 2, it indicates that the rate of change of position tracking difficulty is much higher than the rate of change of vibration intensity. The position tracking trend weight coefficient is set to 0.7 and the damping control trend weight coefficient is set to 0.3, determining that the dominant control direction is position tracking strongly dominant. If the ratio is less than or equal to 1, it indicates that the rate of change of vibration intensity is higher than the rate of change of position tracking difficulty. The damping control trend weight coefficient is set to 0.6 and the position tracking trend weight coefficient is set to 0.4, and the control dominance direction is determined to be damping control dominance.

[0154] If the trend determination result shows a reverse trend, it indicates that the change in position tracking difficulty and the change in turntable vibration intensity at the current angle are mutually restrictive. The turntable control device further determines the absolute values ​​of the two change slopes. If the absolute value of the slope of the change rate of curvature of the position tracking path is greater than the absolute value of the slope of the change rate of vibration amplitude of the damping control path, it indicates that the change in position tracking difficulty is more significant, and the control direction is determined to be position tracking dominant. If the absolute value of the slope of the change rate of vibration amplitude of the damping control path is greater than the absolute value of the slope of the change rate of curvature of the position tracking path, it indicates that the change in turntable vibration intensity is more significant, and the control direction is determined to be damping control dominant. If the two absolute values ​​are equal, the control direction is determined to be position tracking and damping control jointly dominant.

[0155] Based on the above-mentioned discrimination logic, the turntable control device outputs the dominant control direction for the current angle.

[0156] Step 3082: Perform principal component amplitude retention analysis based on the position tracking current vector corresponding to the control dominant direction and the position tracking control path to obtain the position tracking control current vector.

[0157] Optionally, the turntable control device extracts the position tracking current vector corresponding to the current angle of the position tracking control path. The position tracking current vector is the current vector on the position tracking control path that corresponds one-to-one with the current angle position, including the current amplitude and current direction, and is used to provide the active torque required for position tracking.

[0158] Principal component amplitude retention analysis refers to retaining the principal component amplitude in the position tracking current vector that matches the control dominance direction, while eliminating or weakening irrelevant components, to ensure that the position tracking current vector can adapt to the current control dominance requirements and avoid interference with the subsequent damping control current vector.

[0159] In the specific analysis process, the turntable control device decomposes the position tracking current vector into a primary position tracking component and a secondary position tracking component. The primary position tracking component refers to the current component that is aligned with the position tracking control direction and can directly provide the active torque. The secondary position tracking component refers to redundant current components generated by factors such as mechanical errors and electromagnetic interference that do not participate in the active torque output. Based on the dominant control direction obtained in step 3081, the turntable control device determines the retention ratio of the primary component amplitude. The retention ratio refers to the proportion of the retained position tracking primary component amplitude to the original position tracking primary component amplitude, ranging from 0.8 to 1, with the specific value determined based on the dominant control direction.

[0160] If the dominant control direction is position tracking-dominant, the turntable control device sets the main component amplitude retention ratio to 0.95, retaining 95% of the position tracking main component amplitude, and reducing the amplitude of the secondary position tracking component to 5% of its original amplitude to prevent the secondary component from interfering with the torque output of the main component. If the dominant control direction is strong position tracking-dominant, the main component amplitude retention ratio is set to 1.0, fully retaining the entire amplitude of the position tracking main component, and reducing the amplitude of the secondary position tracking component to less than 1% of its original amplitude, maximizing the effect of the position tracking main component. If the dominant control direction is damping control-dominant, the main component amplitude retention ratio is set to 0.8, retaining 80% of the position tracking main component amplitude, and appropriately weakening the position tracking main component to reserve space for subsequent damping control current vector superposition. If the dominant control direction is cooperative-dominant, the main component amplitude retention ratio is set to 0.9, retaining 90% of the position tracking main component amplitude, and simultaneously retaining 10% of the position tracking secondary component amplitude, achieving cooperative adaptation with damping control.

[0161] The turntable control device adjusts the amplitude of the principal and secondary components of the position tracking current vector according to the determined principal component amplitude retention ratio. After the adjustment is completed, the adjusted position tracking principal and secondary components are resynthesized to obtain the position tracking control current vector.

[0162] Step 3083: Based on the position tracking control current vector and the damping control current vector corresponding to the damping control path, the composite control current vector is obtained by vector superposition.

[0163] Optionally, the turntable control device extracts the damping control current vector corresponding to the current angle of the damping control path. The damping control current vector is the current vector on the damping control path that corresponds one-to-one with the current angular position, including the current amplitude and current direction, and is used to provide the damping power required for vibration suppression. Vector superposition refers to superimposing the position tracking control current vector and the damping control current vector according to the vector synthesis rules to obtain a composite control current vector that can simultaneously meet the requirements of position tracking and vibration suppression.

[0164] During the specific superposition process, the turntable control device determines the composite coordinate system of the two current vectors. The composite coordinate system adopts the coordinate system corresponding to the stator winding of the direct drive turntable motor to ensure the accuracy of vector superposition.

[0165] The turntable control device extracts the amplitude and direction of the position tracking control current vector and the amplitude and direction of the damping control current vector respectively. Combined with the control dominant direction obtained in step 3081, the superposition weight of the two current vectors is determined. The superposition weight is consistent with the trend weight coefficient in step 3081, that is, the superposition weight of the position tracking control current vector is equal to the position tracking trend weight coefficient, and the superposition weight of the damping control current vector is equal to the damping control trend weight coefficient.

[0166] The turntable control device performs weighted superposition of two current vectors according to their superposition weights: the amplitude of the position tracking control current vector is multiplied by its superposition weight to obtain the weighted position tracking control current vector. The amplitude of the damping control current vector is multiplied by its superposition weight to obtain the weighted damping control current vector. Based on the directions of the two weighted current vectors, the angle between them is calculated. If the angle is 0 degrees, it means the two current vectors are in the same direction; the amplitudes of the two weighted current vectors are added together, keeping the direction unchanged, to obtain the composite control current vector. If the angle is 180 degrees, it means the two current vectors are in opposite directions; the amplitudes of the two weighted current vectors are subtracted, and the direction of the current vector with the larger amplitude is taken to obtain the composite control current vector. If the angle is between 0 and 180 degrees, the parallelogram rule is used for synthesis. A parallelogram is constructed with the two weighted current vectors as adjacent sides; the diagonal of the parallelogram is the direction of the composite control current vector, and the length of the diagonal is the amplitude of the composite control current vector.

[0167] After superposition, the turntable control device verifies the amplitude of the synthesized control current vector to ensure that its amplitude does not exceed the upper limit of the current amplitude obtained in step 3041. If the amplitude of the synthesized control current vector is less than or equal to the upper limit of the current amplitude, it is used as the synthesized control current vector. If the amplitude of the synthesized control current vector is greater than the upper limit of the current amplitude, the direction of the synthesized control current vector remains unchanged, and its amplitude is proportionally reduced to the upper limit of the current amplitude. The reduction ratio is the ratio of the upper limit of the current amplitude to the amplitude of the original synthesized control current vector, ensuring that the synthesized control current vector meets the motor temperature rise safety requirements, thus obtaining the synthesized control current vector.

[0168] Step 3084: Project the composite control current vector onto the preset stationary coordinate system at the current rotor electrical angle of the direct drive turntable to obtain the composite control direction for the current angle.

[0169] Optionally, the turntable control device collects the current rotor electrical angle of the direct drive turntable. The current rotor electrical angle refers to the electrical angle of the rotor of the direct drive turntable drive motor relative to the stator winding. It is detected in real time by the position detection module of the turntable control device and can accurately reflect the relative position relationship between the rotor and the stator winding. Its value ranges from 0 degrees to 360 degrees and has a fixed proportional relationship with the mechanical angle of the direct drive turntable. This proportional relationship is determined by the number of magnetic poles of the drive motor and can be directly obtained through the design parameters of the direct drive turntable.

[0170] The preset stationary coordinate system refers to the coordinate system that is fixedly connected to the stator of the direct drive turntable motor. It is a fixed reference coordinate system used to uniformly represent the direction of the current vector and ensure the consistency of the control direction.

[0171] During the projection process, the turntable control device determines the angle between the current rotor electrical angle and the preset stationary coordinate system. This angle is the actual value of the current rotor electrical angle, as the preset stationary coordinate system is a fixed coordinate system, and the rotor electrical angle itself is the angle of the rotor relative to this coordinate system. The turntable control device uses the synthetic control current vector obtained in step 3083 as the vector to be projected, and takes the horizontal axis of the preset stationary coordinate system as the reference axis. Based on the current rotor electrical angle, the vector to be projected is decomposed into components in the horizontal and vertical directions of the preset stationary coordinate system. During the decomposition process, the turntable control device calculates the product of the amplitude of the synthetic control current vector and the cosine of the current rotor electrical angle to obtain the current component in the horizontal direction of the preset stationary coordinate system. It also calculates the product of the amplitude of the synthetic control current vector and the sine of the current rotor electrical angle to obtain the current component in the vertical direction of the preset stationary coordinate system. The turntable control device determines the specific direction of the composite control current vector in the preset stationary coordinate system based on the current components in the two coordinate axis directions. This direction is the composite control direction for the current angle. Its direction is determined by the ratio of the two coordinate axis components, and its amplitude is obtained by taking the square root of the sum of the squares of the two coordinate axis components.

[0172] The turntable control device verifies the projected composite control direction to ensure that it accurately corresponds to the control requirements of the current angle. If the projected direction is consistent with the dominant control direction obtained in step 3081 and the amplitude meets the upper limit requirement of the current amplitude, then this direction is determined as the composite control direction for the current angle. If the deviation between the projected direction and the dominant control direction is greater than the preset direction deviation threshold (the preset direction deviation threshold is set according to the control accuracy requirements of the direct drive turntable, usually between 1 and 3 degrees), then the projection calculation parameters are readjusted, and projection is performed again until the projected direction meets the requirements, and the composite control direction for the current angle is output.

[0173] The embodiments of the present invention realize the precise and adaptive generation of composite control directions, further improving the control accuracy and adaptability of the current angle of the direct drive turntable, ensuring that position tracking and vibration suppression work together, effectively suppressing interference in the control process, improving the stability of the direct drive turntable operation, and thus realizing uniform positioning control of the direct drive turntable within the full circumference range.

[0174] Furthermore, the positioning error segmentation control device for direct-drive turntables provided by the present invention will be described below. The positioning error segmentation control device for direct-drive turntables described below can be referred to in correspondence with the positioning error segmentation control method for direct-drive turntables described above.

[0175] Optionally, refer to Figure 2 , Figure 2 This is a schematic diagram of the positioning error segmentation control device for a direct-drive turntable provided by the present invention. The positioning error segmentation control device for a direct-drive turntable includes:

[0176] The coupling impedance analysis module 210 is used to perform electromechanical coupling impedance analysis based on the full circumferential angle of the direct drive turntable and the corresponding drive current feedback sequence, so as to obtain the full circumferential mechanical impedance distribution.

[0177] The spatial topology module 220 is used to perform multi-dimensional spatial topology segmentation based on the full-circumference mechanical impedance distribution to obtain angular sub-regions with homogeneous force characteristics and corresponding region boundaries.

[0178] The composite control module 230 is used to perform path allocation based on each angle sub-region and its corresponding region boundary, to obtain the position tracking control path and damping control path corresponding to each angle sub-region, and to perform path analysis based on the position tracking control path and damping control path to obtain the composite control direction for the current angle.

[0179] The torque output distribution module 240 is used to distribute torque output based on the composite control direction and real-time position deviation to obtain the drive current command of the direct drive turntable.

[0180] The embodiments of the present invention solve the technical problem that the positioning accuracy decreases in local areas and is accompanied by residual oscillations due to the adoption of a global unified control strategy, improve the positioning accuracy of the direct drive turntable in local angle ranges, and realize uniform positioning control of the direct drive turntable in the full circumference range.

[0181] Please see Figure 3 , Figure 3 An embodiment diagram of an electronic device provided in accordance with the present invention. For example... Figure 3 As shown, an embodiment of the present invention provides an electronic device 300, including a memory 310, a processor 320, and a computer program 311 stored in the memory 310 and executable on the processor 320. When the processor 320 executes the computer program 311, it implements the processes of steps 10 to 40.

[0182] Please see Figure 4 , Figure 4 An embodiment diagram of a computer-readable storage medium provided in accordance with an embodiment of the present invention is shown. Figure 4 As shown, this embodiment provides a computer-readable storage medium 400 on which a computer program 311 is stored. When the computer program 311 is executed by a processor, it implements the processes of steps 10 to 40.

[0183] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the positioning error segmentation control method for direct drive turntables provided by the above methods. The method includes process substitution from step 10 to step 40, without causing the essence of the corresponding technical solution to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A segmented control method for positioning error of a direct-drive rotary table, characterized in that, include: Electromechanical coupling impedance analysis was performed based on the full circumferential angle of the direct-drive rotary table and the corresponding drive current feedback sequence to obtain the full circumferential mechanical impedance distribution. Based on the full-circumference mechanical impedance distribution, multi-dimensional spatial topology segmentation is performed to obtain angular sub-regions with homogeneous force characteristics and corresponding region boundaries. Path allocation is performed based on each angle sub-region and its corresponding region boundary to obtain the position tracking control path and damping control path corresponding to each angle sub-region. Path analysis is then performed based on the position tracking control path and the damping control path to obtain the composite control direction for the current angle. Based on the composite control direction and real-time position deviation, torque output is distributed to obtain the drive current command for the direct-drive turntable.

2. The segmented positioning error control method for a direct-drive rotary table according to claim 1, characterized in that, The path allocation based on each angle sub-region and its corresponding region boundary, to obtain the position tracking control path and damping control path corresponding to each angle sub-region, includes: Based on the equivalent mechanical stiffness value corresponding to each angular sub-region and the trajectory of the preset target position, a potential energy gradient is constructed to obtain the position potential energy vector field characterizing the direction of the required restoring torque of the rotor at each angular position. Based on the position potential energy vector field and the current angular position of the direct drive turntable, the gradient descent direction is analyzed to obtain the direction of the main driving torque for position tracking control. Based on the equivalent mechanical damping value and the real-time angular velocity of the rotor corresponding to each angular sub-region, the power flow direction is determined to obtain the power exchange direction required for damping control. Based on the active torque direction and the power exchange direction, path allocation is performed to obtain the position tracking control path and damping control path corresponding to each angular sub-region.

3. The segmented positioning error control method for a direct-drive rotary table according to claim 2, characterized in that, The path allocation based on the active torque direction and the power exchange direction to obtain the position tracking control path and damping control path corresponding to each angular sub-region includes: Based on the power exchange direction and the winding resistance parameters of the direct drive turntable, the Joule heat loss boundary is defined to obtain the upper limit of the current amplitude without exceeding the motor temperature rise limit. Based on the cogging torque distribution characteristics of the direct drive turntable and the active torque direction, ripple cancellation vector synthesis is performed to obtain the ripple suppression component. The ripple suppression component is restricted to the current circle within the upper limit of the current amplitude to obtain a current vector with amplitude constraint. Based on the continuity comparison of the current vector at the boundary of the adjacent angle sub-region and the power exchange direction, the angular deviation of the current vector direction on both sides of the boundary is identified. Based on the included angle deviation, the shortest circular arc trajectory of the current vectors on both sides of the connecting boundary is generated in the vector space, and the position tracking control path and damping control path are obtained within the full circumference range.

4. The segmented positioning error control method for a direct-drive rotary table according to claim 1, characterized in that, The path analysis based on the position tracking control path and the damping control path to obtain the composite control direction for the current angle includes: Based on the angle sequence of the position tracking control path, the curvature change rate is analyzed to obtain the curvature change rate of the position tracking path. Based on the current amplitude sequence of the damping control path, the fluctuation range is analyzed to obtain the vibration amplitude change rate of the damping control path. A two-dimensional feature space is constructed based on the curvature change rate of the position tracking path and the vibration amplitude change rate of the damping control path to obtain a joint feature map of the two change rates. Based on the slope of the two rate of change components in the dual rate of change joint feature map, a trend consistency comparison analysis is performed to obtain the trend determination result. Based on the trend determination result, combined with the current vectors corresponding to the position tracking control path and the damping control path, a composite control direction for the current angle is obtained through synthesis analysis at the current angle.

5. The segmented positioning error control method for a direct-drive rotary table according to claim 4, characterized in that, The composite control direction for the current angle is obtained by combining the current vectors corresponding to the position tracking control path and the damping control path based on the trend determination result at the current angle, including: Based on the trend determination results, the control dominance is determined to obtain the control dominance direction for the current angle. Based on the position tracking current vector corresponding to the dominant control direction and the position tracking control path, principal component amplitude retention analysis is performed to obtain the position tracking control current vector. The composite control current vector is obtained by superimposing the position tracking control current vector and the damping control current vector corresponding to the damping control path. The composite control current vector is projected onto a preset stationary coordinate system at the current rotor electrical angle of the direct-drive turntable to obtain the composite control direction for the current angle.

6. The segmented positioning error control method for a direct-drive rotary table according to claim 1, characterized in that, The multi-dimensional spatial topological segmentation based on the full-circumference mechanical impedance distribution to obtain angular sub-regions with homogeneous force characteristics and corresponding region boundaries includes: Based on the full-circumference mechanical impedance distribution, the ratio trajectory of active power to reactive power is tracked to obtain the full-circumference energy efficiency slope sequence characterizing the change in electromechanical energy conversion efficiency. Based on the full-circumference energy efficiency slope sequence, zero-crossing crossover detection is performed to identify the angle position where the energy efficiency slope changes from positive to negative or from negative to positive, thereby obtaining energy efficiency polarity reversal candidate points. Based on the tooth cogging period base determined by the direct-drive turntable stator winding structure, the energy efficiency polarity reversal candidate points are periodically aligned and constrained. The candidate point with the smallest deviation from the position of an integer multiple of the tooth cogging period is retained to obtain the abrupt change reference point. Based on the phase lag angle sequence in the full-circumference mechanical impedance distribution, the phase-locked interval is extracted, and the continuous angle segment where the phase lag angle remains constant is identified to obtain the target phase plateau region. Based on the mutation reference point and the target phase platform region, a spatiotemporal overlap comparison is performed to obtain each angle sub-region and its corresponding region boundary.

7. The segmented positioning error control method for a direct-drive rotary table according to claim 6, characterized in that, The process of performing spatiotemporal overlap comparison based on the mutation reference point and the target phase plateau region to obtain each angular sub-region and its corresponding region boundary includes: Based on the mutation reference point and the target phase plateau region, a spatiotemporal overlap comparison is performed to determine the angular coordinates of the polarity reversal position and the edge of the target phase plateau region, thus obtaining the target boundary anchor point. Based on the target boundary anchor point, the full circumference angle is cut into angle segments, and the direction consistency of the impedance amplitude monotonicity in each angle segment is judged to obtain angle sub-units with a single increasing or decreasing trend. Based on the impedance increase / decrease direction jump relationship of adjacent angle sub-units, adjacent sub-units are merged, and angle sub-units with the same increase / decrease direction and continuous impedance amplitude transition are merged to obtain homogeneous force regions. Based on the boundary angle coordinates of the homogeneous force region, the electrical commutation points are aligned to update the region boundary to the angle position corresponding to the most recent electrical commutation moment, thereby obtaining each angle sub-region and its corresponding region boundary.

8. A segmented positioning error control device for a direct-drive rotary table, characterized in that, Used to implement the segmented positioning error control method for direct drive turntable as described in any one of claims 1 to 7; The positioning error segmentation control device for the direct-drive turntable includes: The coupling impedance analysis module is used to perform electromechanical coupling impedance analysis based on the full circumferential angle of the direct drive turntable and the corresponding drive current feedback sequence, so as to obtain the full circumferential mechanical impedance distribution. The spatial topology module is used to perform multi-dimensional spatial topology segmentation based on the full-circumference mechanical impedance distribution to obtain angular sub-regions with homogeneous force characteristics and corresponding region boundaries. The composite control module is used to allocate paths based on each angle sub-region and its corresponding region boundary, obtain position tracking control paths and damping control paths corresponding to each angle sub-region, and perform path analysis based on the position tracking control paths and the damping control paths to obtain the composite control direction for the current angle. The torque output distribution module is used to distribute torque output based on the composite control direction and real-time position deviation to obtain the drive current command of the direct drive turntable.

9. An electronic device, comprising: Memory, used to store computer software programs; A processor for reading and executing the computer software program, characterized in that, when the processor executes the computer software program, it implements the segmented positioning error control method for a direct-drive turntable as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, wherein a computer software program is stored therein, characterized in that, When the computer software program is executed by the processor, it implements the segmented positioning error control method for direct drive turntable as described in any one of claims 1 to 7.

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