Double-sided polishing control method and system based on concave-convex morphology of polishing disc surface

Abstract

This invention discloses a double-sided polishing control method and system based on the concave-convex shape of the polishing disc surface, belonging to the field of intelligent control technology. The method includes: setting an initial reference rotational speed of the planetary wheel, generating a first initial polishing path and a second initial polishing path; obtaining a first tangential resistance vector and a second tangential resistance vector, calculating the difference in tangential force between the two sides, and triggering a path planner when the difference in tangential force between the two sides is greater than or equal to a preset threshold; obtaining a first compensation speed increment and a second compensation speed increment; modulating the initial external gear rotational speed of the planetary wheel to obtain a modulated speed signal; sending the modulated speed signal, the first compensation speed increment, and the second compensation speed increment to the upper and lower disc drive motors of the planetary wheel to obtain a first reconstructed polishing path and a second reconstructed polishing path. This solves the technical problem in the prior art where uneven force on the upper and lower surfaces during double-sided polishing leads to poor polishing uniformity, achieving the technical effect of improving the uniformity of double-sided polishing of the workpiece.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology, specifically to a double-sided polishing control method and system based on the concave-convex shape of the polishing disc surface. Background Technology

[0002] Double-sided polishing is widely used in high-precision surface processing of workpieces such as semiconductor wafers, optical glass, ceramic substrates, and precision metal sheets. It achieves material removal and surface smoothing on both sides of the workpiece through the synchronous action of upper and lower polishing discs. Existing double-sided polishing equipment typically uses a fixed rotation speed or preset trajectory to drive the planetary gear. During actual processing, factors such as polishing disc wear, local unevenness, uneven abrasive distribution, and changes in workpiece contact state can easily cause dynamic deviations in the tangential forces on the upper and lower surfaces, leading to inconsistent material removal rates on both sides. Especially in long-term continuous processing or high-precision polishing scenarios, traditional control methods struggle to adjust the polishing path in real time according to changes in disc condition, easily causing problems such as localized over-polishing, decreased polishing uniformity, and poor surface processing stability. Summary of the Invention

[0003] This application provides a double-sided polishing control method and system based on the concave-convex shape of the polishing disc, which solves the technical problem in the prior art that the uneven force on the upper and lower surfaces during double-sided polishing leads to poor polishing uniformity.

[0004] The first aspect of this application provides a double-sided polishing control method based on the concave-convex shape of the polishing disc surface, the method comprising: The initial reference speed of the planetary wheel is set, and a first initial polishing path and a second initial polishing path are generated according to the initial reference speed. The first tangential resistance vector and the second tangential resistance vector of the upper and lower surfaces are obtained through a sensor array. The difference in tangential force between the two surfaces is calculated based on the first tangential resistance vector and the second tangential resistance vector. When the difference in tangential force between the two surfaces is greater than or equal to a preset threshold, the path planner is triggered. The path planner performs speed increment decoupling calculation based on the difference in tangential force between the two surfaces to obtain a first compensation speed increment and a second compensation speed increment. A frequency conversion modulation function is introduced to modulate the initial external gear speed of the planetary wheel to obtain a modulation speed signal. The modulation speed signal, the first compensation speed increment and the second compensation speed increment are sent to the upper and lower disk drive motors of the planetary wheel to obtain a first reconstructed polishing path and a second reconstructed polishing path.

[0005] A second aspect of this application provides a double-sided polishing control system based on the uneven morphology of a polishing disc surface, the system comprising: Initial path generation module: Sets the initial reference speed of the planetary wheel, and generates a first initial polishing path and a second initial polishing path for polishing according to the initial reference speed; Monitoring module: Obtains the first tangential resistance vector and the second tangential resistance vector of the upper and lower surfaces through a sensor array, calculates the difference in tangential force between the two surfaces based on the first tangential resistance vector and the second tangential resistance vector, and triggers the path planner when the difference in tangential force between the two surfaces is greater than or equal to a preset threshold; Decoupling calculation module: The path planner performs speed increment decoupling calculation based on the difference in tangential force between the two surfaces to obtain a first compensation speed increment and a second compensation speed increment; Variable frequency modulation module: Introduces a variable frequency modulation function to modulate the initial external gear speed of the planetary wheel to obtain a modulated speed signal; Path reconstruction module: Sends the modulated speed signal, the first compensation speed increment and the second compensation speed increment to the upper and lower disk drive motors of the planetary wheel to obtain a first reconstructed polishing path and a second reconstructed polishing path.

[0006] One or more technical solutions provided in this application have at least the following technical effects or advantages: First, the initial reference speed of the planetary wheel is set, and a first initial polishing path and a second initial polishing path are generated according to the initial reference speed. Next, the first and second tangential resistance vectors of the upper and lower surfaces are acquired through a sensor array. The difference in tangential force between the two surfaces is calculated based on the first and second tangential resistance vectors. When the difference in tangential force between the two surfaces is greater than or equal to a preset threshold, the path planner is triggered. The path planner performs speed increment decoupling calculation based on the difference in tangential force between the two surfaces to obtain a first compensation speed increment and a second compensation speed increment. Then, a frequency conversion modulation function is introduced to modulate the initial external gear speed of the planetary wheel, and the modulated speed signal is obtained. Finally, the modulated speed signal, the first compensation speed increment, and the second compensation speed increment are sent to the upper and lower disk drive motors of the planetary wheel to obtain a first reconstructed polishing path and a second reconstructed polishing path. This solves the technical problem in the prior art where uneven force on the upper and lower surfaces during double-sided polishing leads to poor polishing uniformity, achieving the technical effect of improving the uniformity of double-sided polishing of the workpiece. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 A schematic flowchart of a double-sided polishing control method based on the concave-convex shape of a polishing disc surface, provided in an embodiment of this application; Figure 2This is a schematic diagram of a double-sided polishing control system based on the concave-convex shape of the polishing disc, provided in an embodiment of this application.

[0009] Figure labeling: Initial path generation module 11, monitoring module 12, decoupling calculation module 13, frequency conversion modulation module 14, path reconstruction module 15. Detailed Implementation

[0010] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0011] Example 1, as Figure 1 As shown, this application provides a double-sided polishing control method based on the uneven morphology of the polishing disc surface, wherein the method includes: Set the initial reference speed of the planetary wheel, and generate a first initial polishing path and a second initial polishing path for polishing according to the initial reference speed.

[0012] Furthermore, the method of generating a first initial polishing path and a second initial polishing path for polishing according to the initial reference rotation speed also includes: Read the device geometric constants of the planetary gear and the center distance between the center of the planetary gear and any point M on the workpiece; based on the device geometric constants of the planetary gear, define the initial reference speed including the initial upper plate speed, the initial lower plate speed, the sun gear speed, and the initial external gear ring speed; based on the center distance between the center of the planetary gear and any point M on the workpiece, perform two-dimensional coordinate trajectory calculation according to the initial reference speed, and discretize to obtain a first set of initial trajectory points and a second set of initial trajectory points; use the first set of initial trajectory points and the second set of initial trajectory points to generate a first initial polishing path and a second initial polishing path.

[0013] First, the device geometric constants of the planetary gear and the center distance between the planetary gear center and any point M on the workpiece are read. The device geometric constants include at least the radius of the sun gear, the radius of the external gear ring, the radius of the planetary gear, the effective polishing radius of the upper and lower polishing discs, and the meshing transmission ratio between the planetary gear and the sun gear. The arbitrary point M on the workpiece is a preset sampling point on the workpiece surface, and the center distance is the radial distance from the planetary gear rotation center to the arbitrary point M. Then, a double-sided polishing kinematic model is established based on the device geometric constants, and the initial reference speeds are defined as the initial upper disc speed, the initial lower disc speed, the sun gear speed, and the initial external gear ring speed. The upper and lower polishing discs perform rotational motions in the same or opposite directions, respectively, and the sun gear and external gear ring drive the planetary gear to perform a compound revolution and rotational motion. During the motion calculation process, a two-dimensional plane is established with the polishing disc center as the reference point. A coordinate system is used, and the temporal position of any point M on the workpiece surface is sampled at a preset time step. Based on the coupled motion relationship between the initial upper disk rotation speed, the initial lower disk rotation speed, the sun gear rotation speed, and the initial external gear rotation speed, the first two-dimensional trajectory coordinates of any point M on the upper polishing disk surface and the second two-dimensional trajectory coordinates on the lower polishing disk surface are calculated. Subsequently, the trajectory coordinates calculated in the continuous time domain are discretized to generate a first set of initial trajectory points and a second set of initial trajectory points, wherein each set of trajectory points contains two-dimensional coordinate position data under the corresponding timestamp. Finally, trajectory connection, trajectory smoothing, and boundary continuity processing are performed on the first set of initial trajectory points and the second set of initial trajectory points, respectively, to generate a first initial polishing path and a second initial polishing path for double-sided polishing.

[0014] The first tangential resistance vector and the second tangential resistance vector of the upper and lower surfaces are obtained by the sensor array. The difference in tangential force between the two surfaces is calculated based on the first tangential resistance vector and the second tangential resistance vector. When the difference in tangential force between the two surfaces is greater than or equal to a preset threshold, the path planner is triggered.

[0015] Multiple sets of two-dimensional force sensing units are arranged at corresponding positions on the upper and lower polishing disc support structures of the double-sided polishing equipment. Each two-dimensional force sensing unit is used to collect the changes in tangential force between the workpiece and the polishing disc in real time during the polishing process. The controller synchronously reads the X-axis tangential force and Y-axis tangential force output by each two-dimensional force sensing unit according to a preset sampling period, and constructs the real-time first tangential resistance vector of the upper surface and the real-time second tangential resistance vector of the lower surface, respectively. The real-time first tangential resistance vector of the upper surface is expressed as: The real-time second tangential drag vector of the lower surface is expressed as: ,in, and These represent the real-time tangential components of the upper surface in the X-axis and Y-axis directions, respectively. and The values ​​represent the real-time tangential forces on the lower surface in the X-axis and Y-axis directions, respectively, where i and j represent the unit direction vectors of the X-axis and Y-axis in the two-dimensional coordinate system, respectively. Subsequently, the controller calculates the vector magnitudes of the first and second tangential resistance vectors, and calculates the difference in tangential forces between the two based on the difference in magnitudes. During continuous monitoring, when the difference in tangential forces between the two surfaces is greater than or equal to a preset threshold, it is determined that there is a significant imbalance in the tangential force state of the upper and lower polished surfaces. A path reconstruction trigger signal is sent to the path planner, which then initiates the subsequent compensation speed increment calculation and the reconstruction polishing path generation process.

[0016] Furthermore, the path planner is triggered when the difference in tangential forces on both sides exceeds a preset threshold. The method for calculating the preset threshold includes: The time-domain signal of the difference between the two tangential forces is collected, and statistical analysis is performed on the time-domain signal of the difference between the two tangential forces to obtain the average value and the root mean square error of the difference between the two tangential forces. The preset threshold is calculated based on the sum of the average value and three times the root mean square error of the difference between the two tangential forces.

[0017] During the operation of the double-sided polishing equipment, the time-domain signal of the double-sided tangential force difference is continuously acquired at a preset sampling frequency, and the time-domain signal of the double-sided tangential force difference is buffered according to a sliding time window, wherein the sliding time window corresponds to a preset number of continuous sampling periods; subsequently, the time-domain signal of the double-sided tangential force difference within the sliding time window is statistically analyzed to calculate the average value and the root mean square error of the double-sided tangential force difference, wherein the average value of the double-sided tangential force difference is used to characterize the overall level of the tangential force deviation of the upper and lower surfaces during the current double-sided polishing process, and the root mean square error of the double-sided tangential force difference is used to characterize the degree of fluctuation of the double-sided tangential force; after completing the statistical calculation, the preset threshold is generated based on the sum of the average value of the double-sided tangential force difference and three times the root mean square error of the double-sided tangential force difference, and the preset threshold is expressed as: ,in, Indicates the preset threshold. This represents the average value of the difference in tangential forces between the two surfaces. The mean square error of the difference in tangential force between the two sides is represented by the preset threshold. The controller uses the preset threshold to dynamically compare the real-time difference in tangential force between the two sides. When the real-time difference in tangential force between the two sides is greater than or equal to the preset threshold, it is determined that there is an abnormal force offset or uneven contact of the disk surface during the current double-sided polishing process, and the path planner is triggered to execute the subsequent reconstruction polishing path adjustment process.

[0018] Furthermore, when the difference in tangential force between the two sides is greater than a preset threshold, the path planner is triggered. A laser displacement sensor is installed on the main shaft of the planetary wheel. The spatial offset is obtained based on the laser displacement sensor. The spatial offset includes the axial yaw angle and the axial displacement increment. When the difference in tangential force between the two sides is less than the preset threshold, it is determined whether either the axial yaw angle or the axial displacement increment is greater than a first threshold. If at least one of them is greater than the first threshold, the path planner is triggered.

[0019] Multiple sets of laser displacement sensors are installed on the radially outer side and axial end of the planetary gear spindle. Each laser displacement sensor is used to detect the spatial attitude change of the planetary gear spindle in real time during the polishing process. The controller synchronously reads the measurement data of each laser displacement sensor according to a preset sampling period and calculates the spatial offset of the planetary gear spindle based on the spatial geometric relationship between multiple measurement points. The spatial offset includes at least the axial yaw angle and the axial displacement increment. The axial yaw angle is used to characterize the degree of tilting of the planetary gear spindle relative to the theoretical axis, and the axial displacement increment is used to characterize the offset of the planetary gear spindle along the axial direction relative to the initial reference position. During real-time monitoring, When the difference in tangential force between the two sides is less than the preset threshold, the controller continues to make anomaly judgments on the axial yaw angle and the axial displacement increment to identify potential instability states that have already occurred in spatial attitude deviation but are not directly manifested as tangential force anomalies. Subsequently, the axial yaw angle is compared with the preset yaw angle threshold and the axial displacement increment is compared with the preset axial displacement threshold. When either the axial yaw angle or the axial displacement increment is greater than the corresponding first threshold, it is determined that the current planetary wheel has disk surface contact misalignment, local pressure abnormality, or spindle offset trend. The controller sends a compensation trigger signal to the path planner to start the subsequent reconstruction polishing path adjustment process.

[0020] Furthermore, the method for calculating the preset threshold also includes: The axial deviation angle of the polishing slurry injection direction relative to the planetary gear spindle direction is obtained; when the axial deviation angle of the polishing slurry is greater than a second threshold, the path planner is triggered, wherein the second threshold is obtained by calculating the area of ​​the polishing slurry injection area covered by the polishing slurry injection direction.

[0021] The controller acquires the axial angle of the polishing slurry between the injection direction and the direction of the planetary gear spindle. A jet direction detection component is installed at the outlet of the polishing slurry injection pipe. This component detects the spatial jet direction of the polishing slurry relative to the theoretical central axis of the planetary gear spindle in real time. The controller calculates the axial angle of the polishing slurry based on the spatial direction vector output by the jet direction detection component and the direction vector of the planetary gear spindle. Subsequently, based on the jet coverage area corresponding to the current injection direction, the controller performs a coverage analysis on the actual injection area of ​​the polishing slurry on the polishing disk surface and calculates the coverage ratio between the actual injection area and the target polishing area. A second threshold is generated based on this coverage ratio. When the coverage ratio of the polishing slurry injection area to the target polishing area decreases, the second threshold is reduced accordingly to improve the trigger sensitivity of the path planner. During real-time monitoring, if the axial angle of the polishing slurry is greater than the second threshold, it is determined that the current polishing slurry injection state has deviated from the normal supply direction, which may lead to abnormal abrasive concentration in local polishing areas, uneven lubrication, and a shift in the material removal rate on the disk surface. The controller then sends a path compensation trigger signal to the path planner to execute the subsequent reconstructed polishing path adjustment process.

[0022] The path planner performs velocity increment decoupling calculation based on the difference in tangential forces on both sides to obtain the first compensated velocity increment and the second compensated velocity increment.

[0023] Furthermore, the path planner performs velocity increment decoupling calculations based on the difference in tangential forces on both sides to obtain a first compensated velocity increment and a second compensated velocity increment. The method includes: A proportional-integral control decoupling model is established for the difference in tangential force between the two sides and the disk drive speed. Based on the upper disk adjustment parameters, the speed increment decoupling calculation is performed on the proportional-integral control decoupling model to obtain the first compensation speed increment. Based on the lower disk adjustment parameters, the speed increment decoupling calculation is performed on the proportional-integral control decoupling model to obtain the second compensation speed increment.

[0024] Preferably, a proportional-integral control decoupling model is established between the difference in tangential force on both sides and the disk drive speed. The difference in tangential force on both sides is the difference between the magnitude of the tangential resistance vector on the upper surface and the magnitude of the tangential resistance vector on the lower surface. The path planner establishes independent speed compensation channels for the upper and lower polishing disks based on the changing trend of the tangential force deviation on both sides. During real-time control, the path planner first compares the magnitude of the tangential resistance vector on the upper surface and the magnitude of the tangential resistance vector on the lower surface to determine which side of the polishing disk experiences a greater force. When the force on the upper disk is greater than that on the lower disk, it is determined that the material removal load on the upper surface is too high, requiring a reduction in the local tangential friction load on the upper disk and a simultaneous increase in the material removal capacity of the lower disk. At this time, based on the upper disk adjustment parameters, a speed increment decoupling calculation is performed on the proportional-integral control decoupling model to obtain a first compensation speed increment, and a second compensation speed increment is obtained based on the lower disk adjustment parameters. The first compensation speed increment is expressed as: The second compensation speed increment is expressed as: ,in, This indicates the first compensation speed increment corresponding to the upper plate. This indicates the second compensation speed increment corresponding to the lower plate. This represents the real-time difference in tangential force between the two surfaces. and These represent the ratio adjustment coefficients for the upper and lower parts, respectively. and These represent the integral adjustment coefficients of the upper and lower plates, respectively. The proportional adjustment term is used to quickly respond to the current double-sided tangential force deviation, while the integral adjustment term is used to eliminate the steady-state error accumulated over a long period of time. When the force on the lower plate is greater than that on the upper plate, the adjustment directions of the first compensation speed increment and the second compensation speed increment are reversed to gradually restore the material removal rate of the upper and lower polishing plates to a balanced state.

[0025] Furthermore, the method for obtaining the first compensation velocity increment and the second compensation velocity increment also includes: Compare the absolute values ​​of the first compensation speed increment and the second compensation speed increment; adjust the positive and negative signs of the first compensation speed increment and the second compensation speed increment according to the comparison result of the absolute values.

[0026] After calculating the first and second compensation speed increments, the path planner obtains the absolute values ​​of both increments and compares them to determine the primary compensation side for force displacement during the current double-sided polishing process. When the absolute value of the first compensation speed increment is greater than the absolute value of the second compensation speed increment, it is determined that the tangential force displacement corresponding to the upper polishing disk is greater. The first compensation speed increment is then set as the primary adjustment increment, and a deceleration or acceleration sign is assigned to the first compensation speed increment based on the current direction of the double-sided tangential force difference. Simultaneously, the second compensation speed increment is adjusted accordingly. The increment is set as a collaborative compensation increment, and is adjusted in the opposite sign direction to the first compensation speed increment. When the absolute value of the second compensation speed increment is greater than the absolute value of the first compensation speed increment, it is determined that the tangential force offset corresponding to the lower polishing disk is greater. Then, the second compensation speed increment is set as the main adjustment increment, and a deceleration sign or an acceleration sign is assigned to the second compensation speed increment according to the current direction of the difference in tangential force between the two sides. At the same time, the first compensation speed increment is set as a collaborative compensation increment, and is adjusted in a linkage manner in the opposite sign direction. The positive and negative signs correspond to the direction of increasing drive motor speed and the direction of decreasing drive motor speed, respectively.

[0027] A frequency conversion modulation function is introduced to modulate the initial external gear speed of the planetary wheel, and the modulated speed signal is obtained.

[0028] Furthermore, a frequency conversion modulation function is introduced to modulate the initial external gear speed of the planetary gear to obtain the modulated speed signal. The method includes: The amplitude is calculated based on the difference in tangential forces on both sides to obtain the amplitude value; a sinusoidal frequency modulation function and the amplitude value are introduced to perform frequency modulation to obtain the frequency modulation function; the frequency modulation function is superimposed and modulated with the initial external gear ring speed to obtain the modulated speed signal.

[0029] The controller calculates the amplitude based on the real-time difference in tangential forces on both sides, obtaining the amplitude value. This amplitude value is directly proportional to the difference in tangential forces on both sides, ensuring that a larger deviation in the force on both sides corresponds to a higher intensity of trajectory disturbance. During the amplitude calculation, a linear mapping is performed between a preset modulation coefficient and the real-time difference in tangential forces on both sides to obtain the real-time modulation amplitude, which is expressed as: ,in, Indicates real-time modulation amplitude. Represents the modulation coefficient. This represents the real-time difference in tangential force between the two sides. Subsequently, a sinusoidal frequency modulation function and the amplitude value are introduced for frequency modulation to obtain the frequency modulation function. To avoid resonance between the modulation frequency and the device's natural frequency, the controller selects the modulation frequency based on the planetary wheel's revolution frequency and the device's dynamic response characteristics, setting the modulation frequency to 3 to 5 times the planetary wheel's revolution frequency to drive the workpiece to form a micro-perturbation ripple motion trajectory on the polishing disc surface. The frequency modulation function is expressed as: ,in, This represents the frequency conversion modulation function. The modulation frequency is represented by: After generating the frequency conversion modulation function, the frequency conversion modulation function and the initial external gear ring speed are superimposed and modulated to obtain a modulated speed signal, which is represented as: ,in, This indicates the real-time rotational speed of the external gear ring after modulation. This indicates the initial rotational speed of the external gear ring.

[0030] The modulated speed signal, the first compensation speed increment, and the second compensation speed increment are sent to the upper and lower disk drive motors of the planetary wheel to obtain the first reconstructed polishing path and the second reconstructed polishing path.

[0031] Furthermore, the method of sending the modulated speed signal, the first compensated speed increment, and the second compensated speed increment to the upper and lower disk drive motors of the planetary wheel to obtain the first reconstructed polishing path and the second reconstructed polishing path includes: The modulated speed signal, the first compensation speed increment, and the second compensation speed increment are sent to the upper and lower disk drive motors of the planetary wheel to obtain the reconstructed speed of the planetary wheel; the reconstructed speed is recalculated in two-dimensional coordinates and discretized to obtain a first set of reconstructed trajectory points and a second set of reconstructed trajectory points; a first reconstructed polishing path and a second reconstructed polishing path are generated from the first set of reconstructed trajectory points and the second set of reconstructed trajectory points.

[0032] Preferably, the controller sends the modulated speed signal to the external gear ring drive motor, and sends the first compensated speed increment and the second compensated speed increment to the upper disk drive motor and the lower disk drive motor respectively, so as to perform real-time dynamic correction of the motion state of the upper and lower disks during the double-sided polishing process; subsequently, each drive motor readjusts its corresponding speed parameters according to the received speed adjustment signal to obtain the reconstructed speed of the planetary gear, wherein the reconstructed speed includes at least the reconstructed upper disk speed, the reconstructed lower disk speed, the reconstructed sun gear speed, and the reconstructed external gear ring speed; after completing the reconstructed speed update, the controller re-establishes the two-dimensional dynamic motion model of the workpiece during the double-sided polishing process, and recalculates the two-dimensional coordinate trajectory of any point M on the workpiece surface with the center of the polishing disk as the coordinate origin; wherein, based on the coupled motion between the reconstructed upper disk speed, the reconstructed lower disk speed, the reconstructed sun gear speed, and the reconstructed external gear ring speed... The system calculates the first reconstructed two-dimensional trajectory coordinates of any point M on the workpiece surface on the upper polishing disk and the second reconstructed two-dimensional trajectory coordinates on the lower polishing disk in real time. Then, it discretizes the first and second reconstructed two-dimensional trajectory coordinates calculated in the continuous time domain to generate a first set of reconstructed trajectory points and a second set of reconstructed trajectory points. Each set of reconstructed trajectory points contains two-dimensional coordinate position data and corresponding motion direction data at the corresponding sampling time. Finally, it performs trajectory connection, trajectory smoothing, and boundary continuity constraint processing on the first and second sets of reconstructed trajectory points, respectively. The first set of reconstructed trajectory points generates a first reconstructed polishing path, and the second set of reconstructed trajectory points generates a second reconstructed polishing path. This redistributes the motion coverage area of ​​the workpiece on the upper and lower polishing disks, thereby reducing the probability of local repeated polishing and improving the uniformity of double-sided polishing.

[0033] In summary, the embodiments of this application have at least the following technical effects: First, the initial reference speed of the planetary wheel is set, and a first initial polishing path and a second initial polishing path are generated according to the initial reference speed. Next, the first and second tangential resistance vectors of the upper and lower surfaces are acquired through a sensor array. The difference in tangential force between the two surfaces is calculated based on the first and second tangential resistance vectors. When the difference in tangential force between the two surfaces is greater than or equal to a preset threshold, the path planner is triggered. The path planner performs speed increment decoupling calculation based on the difference in tangential force between the two surfaces to obtain a first compensation speed increment and a second compensation speed increment. Then, a frequency conversion modulation function is introduced to modulate the initial external gear speed of the planetary wheel, and the modulated speed signal is obtained. Finally, the modulated speed signal, the first compensation speed increment, and the second compensation speed increment are sent to the upper and lower disk drive motors of the planetary wheel to obtain a first reconstructed polishing path and a second reconstructed polishing path. This solves the technical problem in the prior art where uneven force on the upper and lower surfaces during double-sided polishing leads to poor polishing uniformity, achieving the technical effect of improving the uniformity of double-sided polishing of the workpiece.

[0034] Example 2 is based on the same inventive concept as the double-sided polishing control method based on the concave-convex shape of the polishing disc in the foregoing examples, such as... Figure 2 As shown, this application provides a double-sided polishing control system based on the concave-convex shape of the polishing disc surface, wherein the system includes: Initial path generation module 11: Sets the initial reference speed of the planetary wheel, and generates a first initial polishing path and a second initial polishing path for polishing according to the initial reference speed; Monitoring module 12: Obtains the first tangential resistance vector and the second tangential resistance vector of the upper and lower surfaces through a sensor array, calculates the difference in tangential force between the two surfaces based on the first tangential resistance vector and the second tangential resistance vector, and triggers the path planner when the difference in tangential force between the two surfaces is greater than or equal to a preset threshold; Decoupling calculation module 13: The path planner performs speed increment decoupling calculation based on the difference in tangential force between the two surfaces to obtain a first compensation speed increment and a second compensation speed increment; Variable frequency modulation module 14: Introduces a variable frequency modulation function to modulate the initial external gear speed of the planetary wheel to obtain a modulated speed signal; Path reconstruction module 15: Sends the modulated speed signal, the first compensation speed increment and the second compensation speed increment to the upper and lower disk drive motors of the planetary wheel to obtain a first reconstructed polishing path and a second reconstructed polishing path.

[0035] Furthermore, the initial path generation module 11 is used to perform the following method: Read the device geometric constants of the planetary gear and the center distance between the center of the planetary gear and any point M on the workpiece; based on the device geometric constants of the planetary gear, define the initial reference speed including the initial upper plate speed, the initial lower plate speed, the sun gear speed, and the initial external gear ring speed; based on the center distance between the center of the planetary gear and any point M on the workpiece, perform two-dimensional coordinate trajectory calculation according to the initial reference speed, and discretize to obtain a first set of initial trajectory points and a second set of initial trajectory points; use the first set of initial trajectory points and the second set of initial trajectory points to generate a first initial polishing path and a second initial polishing path.

[0036] Furthermore, the monitoring module 12 is used to perform the following methods: The time-domain signal of the difference between the two tangential forces is collected, and statistical analysis is performed on the time-domain signal of the difference between the two tangential forces to obtain the average value and the root mean square error of the difference between the two tangential forces. The preset threshold is calculated based on the sum of the average value and three times the root mean square error of the difference between the two tangential forces.

[0037] Furthermore, the monitoring module 12 is used to perform the following methods: When the difference in tangential force between the two sides is greater than a preset threshold, the path planner is triggered. A laser displacement sensor is installed on the main shaft of the planetary wheel. The spatial offset is obtained based on the laser displacement sensor. The spatial offset includes the axial yaw angle and the axial displacement increment. When the difference in tangential force between the two sides is less than the preset threshold, it is determined whether either the axial yaw angle or the axial displacement increment is greater than a first threshold. If at least one of them is greater than the first threshold, the path planner is triggered.

[0038] Furthermore, the monitoring module 12 is used to perform the following methods: The axial deviation angle of the polishing slurry injection direction relative to the planetary gear spindle direction is obtained; when the axial deviation angle of the polishing slurry is greater than a second threshold, the path planner is triggered, wherein the second threshold is obtained by calculating the area of ​​the polishing slurry injection area covered by the polishing slurry injection direction.

[0039] Furthermore, the decoupling calculation module 13 is used to perform the following method: A proportional-integral control decoupling model is established for the difference in tangential force between the two sides and the disk drive speed. Based on the upper disk adjustment parameters, the speed increment decoupling calculation is performed on the proportional-integral control decoupling model to obtain the first compensation speed increment. Based on the lower disk adjustment parameters, the speed increment decoupling calculation is performed on the proportional-integral control decoupling model to obtain the second compensation speed increment.

[0040] Furthermore, the decoupling calculation module 13 is used to perform the following method: Compare the absolute values ​​of the first compensation speed increment and the second compensation speed increment; adjust the positive and negative signs of the first compensation speed increment and the second compensation speed increment according to the comparison result of the absolute values.

[0041] Furthermore, the frequency conversion modulation module 14 is used to perform the following method: The amplitude is calculated based on the difference in tangential forces on both sides to obtain the amplitude value; a sinusoidal frequency modulation function and the amplitude value are introduced to perform frequency modulation to obtain the frequency modulation function; the frequency modulation function is superimposed and modulated with the initial external gear ring speed to obtain the modulated speed signal.

[0042] Furthermore, the path reconstruction module 15 is used to perform the following methods: The modulated speed signal, the first compensation speed increment, and the second compensation speed increment are sent to the upper and lower disk drive motors of the planetary wheel to obtain the reconstructed speed of the planetary wheel; the reconstructed speed is recalculated in two-dimensional coordinates and discretized to obtain a first set of reconstructed trajectory points and a second set of reconstructed trajectory points; a first reconstructed polishing path and a second reconstructed polishing path are generated from the first set of reconstructed trajectory points and the second set of reconstructed trajectory points.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A double-sided polishing control method based on the concave-convex shape of the polishing disc surface, characterized in that, The method includes: Set the initial reference speed of the planetary wheel, and generate a first initial polishing path and a second initial polishing path for polishing according to the initial reference speed; The first tangential resistance vector and the second tangential resistance vector of the upper and lower surfaces are obtained by the sensor array. The difference in tangential force between the two surfaces is calculated based on the first tangential resistance vector and the second tangential resistance vector. When the difference in tangential force between the two surfaces is greater than or equal to a preset threshold, the path planner is triggered. The path planner performs velocity increment decoupling calculation based on the difference in bi-plane tangential force to obtain the first compensation velocity increment and the second compensation velocity increment. A frequency conversion modulation function is introduced to modulate the initial external gear speed of the planetary wheel to obtain the modulation speed signal; The modulated speed signal, the first compensation speed increment, and the second compensation speed increment are sent to the upper and lower disk drive motors of the planetary wheel to obtain the first reconstructed polishing path and the second reconstructed polishing path.

2. The double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in claim 1, characterized in that, The method further includes generating a first initial polishing path and a second initial polishing path for polishing according to the initial reference rotation speed, and the method also includes: Read the device geometric constants of the planetary wheel and the center distance between the center of the planetary wheel and any point M on the workpiece; Based on the device geometric constants of the planetary gear, the initial reference speed is defined as including the initial upper plate speed, the initial lower plate speed, the sun gear speed, and the initial external gear speed; Based on the center distance between the planetary wheel center and any point M on the workpiece, a two-dimensional coordinate trajectory is calculated according to the initial reference rotation speed, and the first set of initial trajectory points and the second set of initial trajectory points are discretized. The first initial polishing path and the second initial polishing path are generated using the first set of initial trajectory points and the second set of initial trajectory points.

3. The double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in claim 1, characterized in that, The path planner is triggered when the difference in tangential forces on both sides exceeds a preset threshold. The method for calculating the preset threshold includes: The time-domain signal of the difference between the two tangential forces is collected, and statistical analysis is performed on the time-domain signal of the difference between the two tangential forces to obtain the average value and the root mean square error of the difference between the two tangential forces. The preset threshold is calculated based on the sum of the average value of the difference between the two tangential forces and three times the root mean square deviation of the difference between the two tangential forces.

4. The double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in claim 3, characterized in that, When the difference in the tangential force between the two sides is greater than a preset threshold, the path planner is triggered. A laser displacement sensor is installed on the main shaft of the planetary wheel. The spatial offset is obtained according to the laser displacement sensor. The spatial offset includes the axial yaw angle and the axial displacement increment. When the difference in the two-sided tangential force is less than the preset threshold, it is determined whether either the axial yaw angle or the axial displacement increment is greater than the first threshold. If at least one of them is greater than the first threshold, the path planner is triggered.

5. The double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in claim 4, characterized in that, The method for calculating the preset threshold also includes: Obtain the axial angle of the polishing slurry injection direction relative to the planetary gear spindle direction; When the axial deflection angle of the polishing fluid is greater than the second threshold, the path planner is triggered, wherein the second threshold is obtained by calculating the area of ​​the polishing fluid injection direction covering the polishing area.

6. The double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in claim 1, characterized in that, The path planner performs velocity increment decoupling calculations based on the difference in biaxial tangential forces to obtain a first compensated velocity increment and a second compensated velocity increment. The method includes: Establish a proportional-integral control decoupling model for the difference in tangential force between the two sides and the disk drive speed; Based on the upper plate adjustment parameters, the speed increment decoupling calculation is performed on the proportional-integral control decoupling model to obtain the first compensation speed increment; Based on the lower plate adjustment parameters, the proportional-integral control decoupling model is subjected to speed increment decoupling calculation to obtain the second compensation speed increment.

7. The double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in claim 6, characterized in that, The method for obtaining the first compensation velocity increment and the second compensation velocity increment also includes: Compare the absolute value of the first compensation speed increment with the absolute value of the second compensation speed increment; The signs of the first compensation speed increment and the second compensation speed increment are adjusted based on the absolute value comparison results.

8. The double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in claim 1, characterized in that, The initial external gear speed of the planetary gear is modulated using a frequency conversion modulation function to obtain the modulated speed signal. The method includes: The amplitude is calculated based on the difference in tangential forces on both sides to obtain the amplitude value; A sinusoidal frequency modulation function and the amplitude value are introduced to perform frequency modulation, thereby obtaining the frequency modulation function; The frequency conversion modulation function and the initial external gear ring speed are superimposed and modulated to obtain the modulated speed signal.

9. The double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in claim 1, characterized in that, The method involves sending the modulated speed signal, the first compensated speed increment, and the second compensated speed increment to the upper and lower disk drive motors of the planetary wheel to obtain the first reconstructed polishing path and the second reconstructed polishing path. The modulated speed signal, the first compensation speed increment, and the second compensation speed increment are sent to the upper and lower disk drive motors of the planetary wheel to obtain the reconstructed speed of the planetary wheel; The reconstructed rotational speed is recalculated using two-dimensional coordinate trajectory, and discretized to obtain the first set of reconstructed trajectory points and the second set of reconstructed trajectory points. The first reconstructed polishing path and the second reconstructed polishing path are generated from the first set of reconstructed trajectory points and the second set of reconstructed trajectory points.

10. A double-sided polishing control system based on the concave-convex shape of the polishing disc surface, characterized in that, For implementing the double-sided polishing control method based on the concave-convex shape of the polishing disc surface as described in any one of claims 1-9, the system comprises: Initial path generation module: Sets the initial reference speed of the planetary wheel, and generates a first initial polishing path and a second initial polishing path for polishing according to the initial reference speed; Monitoring module: It acquires the first tangential resistance vector and the second tangential resistance vector of the upper and lower surfaces through a sensor array, calculates the difference in tangential force between the two surfaces based on the first tangential resistance vector and the second tangential resistance vector, and triggers the path planner when the difference in tangential force between the two surfaces is greater than or equal to a preset threshold. Decoupling calculation module: The path planner performs velocity increment decoupling calculation based on the difference in tangential force on both sides to obtain the first compensation velocity increment and the second compensation velocity increment; Frequency conversion modulation module: Introduces a frequency conversion modulation function to modulate the initial external gear speed of the planetary wheel and obtains the modulated speed signal; Path reconstruction module: sends the modulated speed signal, the first compensation speed increment and the second compensation speed increment to the upper and lower disk drive motors of the planetary wheel to obtain the first reconstructed polishing path and the second reconstructed polishing path.

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