A double-station planar finishing method and system

Abstract

The application discloses a double-station plane finishing machining method and system. The application calibrates the pose difference parameter between the substrate calibration measurement station and the machining station, and compensates when the station is switched; generates the constrained dwell time sequence according to the measurement result of the surface to be machined and the dwell time-removal amount mapping model; the control unit establishes the double-layer electronic cam or equivalent double-layer mapping relationship from the time virtual axis to the virtual angle axis and from the virtual angle axis to the two real axes, drives the two real axes to perform circular arc interpolation, and forms a spiral-like covering track at the preset tool position feed; after machining, the target removal amount distribution or the dwell time sequence of the next process is corrected according to the actual removal amount distribution, and the double-station compensation, the controllable dwell time and the closed-loop correction are realized. The application realizes the plane finishing machining which can be implemented, reproduced and more easily converged through the "two-station pose difference calibration compensation, dwell time backstepping and constraint, double-layer electronic cam execution link and closed-loop correction after machining".

Description

Technical Field

[0001] This invention belongs to the field of precision planar finishing and motion control, specifically relating to a planar finishing method and system with a measurement station and a machining station (or a switchable station), particularly relating to in-situ leveling and holding, two-station switching position difference calibration compensation, spiral dwell time field planning, and virtual axis modulation control based on a double-layer electronic cam. Background Technology

[0002] Planar finishing processes (including grinding, regrinding, and polishing) often employ deterministic removal principles: based on morphological deviations measured in place or out of place, the dwell time or equivalent feed rate of the tool at different positions is planned, thereby causing material removal to tend towards the target distribution. The key to this type of method lies in the feasibility of dwell time planning (meeting machine tool dynamic constraints, cycle time, and safety constraints) and the controllable realization of dwell time in the motion control link.

[0003] Existing technologies disclose planar machining apparatuses and methods with tilt detection and compensation capabilities. For example, the applicant's earlier Chinese patent application publication number CN119871097A obtains the contour data of the workpiece and reference datum through in-situ measurement and generates machining instructions to achieve tilt adjustment and machining of the surface to be machined. This type of solution can improve the integration level of measurement and machining. However, during the switching between two stations, due to the superposition of installation errors, guide rail / transmission errors and tooling repetitive positioning errors, the posture of the workpiece after leveling at the measurement station is not necessarily maintained at the machining station. Relying solely on fully closed-loop grating feedback is often insufficient to cover the systematic position and pose difference between the coordinate systems of the two stations.

[0004] Furthermore, dwell time algorithms typically output discrete time series or dwell time distributions. There is still room for improvement in how to achieve a stable and reproducible "time-space" mapping in the controller (e.g., achieving variable-speed dwell without changing the helical geometry coverage) and how to avoid overcutting and oscillations through closed-loop correction after processing. Summary of the Invention

[0005] To address the challenges of maintaining posture consistency after switching between the measurement and machining stations in dual-station planar finishing processes, difficulties in coordinating dwell time execution with trajectory control, and a lack of intuitive post-processing correction, this invention provides a dual-station planar finishing method and system. Through the combined relationship of "two-station posture difference calibration compensation, dwell time back calculation and constraint, dual-layer electronic cam execution link, and post-processing closed-loop correction," a feasible, reproducible, and more convergent planar finishing process is achieved.

[0006] The technical solution adopted in this invention is as follows:

[0007] (1) Use a calibration substrate to calibrate the position and pose difference parameters between the measurement station and the machining station, and store the position and pose difference parameters in the station switching compensation parameter set; when the workpiece is switched from the measurement station to the machining station, call the position and pose difference parameters to compensate for the posture or coordinate.

[0008] (2) Perform in-situ measurement on the surface to be processed at the measurement station, and determine the target removal amount distribution based on the measurement results; based on the pre-established residence time-removal amount mapping model, the discrete residence time sequence is obtained by reverse calculation.

[0009] (3) Apply minimum dwell time constraint and single-cycle total period constraint to the dwell time series, and adjust them in combination with smoothing, amplitude limiting and rate of change limit to reduce the risk of overcutting and oscillation; wherein, the single cycle is the processing process corresponding to the completion of one closed loop by the virtual angle axis.

[0010] (4) The control unit establishes a double-layer electronic cam or equivalent double-layer mapping relationship based on the dwell time sequence. The first layer realizes the mapping from the time virtual axis to the virtual angle axis, and the second layer realizes the mapping from the virtual angle axis to the two real axes. Under the second layer mapping drive, the two real axes perform circular interpolation and feed at a given feed distance when they reach the preset feed position in each revolution, thereby forming a spiral-like covering trajectory.

[0011] (5) After processing, obtain the actual removal amount distribution and correct the target removal amount distribution or residence time series of the next process based on the actual removal amount distribution to form a closed-loop correction.

[0012] The present invention also provides a dual-station planar trimming system, including a measurement unit, a processing unit, a station switching mechanism, a calibration substrate, a substrate calibration component, a control unit, a station switching compensation parameter set, and a removal model library; wherein, the station switching compensation parameter set is used to store the position and orientation difference parameters between the two stations, the removal model library is used to store the dwell time-removal amount mapping model, and the control unit is used to establish a dual-layer electronic cam or an equivalent dual-layer mapping relationship and drive two real axes to perform a spiral-like covering trajectory.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects:

[0014] (1) By calibrating the substrate and compensating for the position difference between the measurement station and the machining station, the workpiece can maintain the same machining reference as the measurement stage after the station is switched, thereby improving the usable accuracy of the dual-station system.

[0015] (2) By back-calculating the dwell time and superimposing the minimum dwell time and the total cycle constraint of a single loop, the dwell time planning can simultaneously meet the removal requirements and the processing cycle requirements, and reduce the dynamic impact during the execution process through smoothing and limiting.

[0016] (3) By using a dual-layer electronic cam execution link consisting of a time virtual axis, a virtual angle axis and two real axes, the dwell time allocation can be explicitly implemented in the motion execution process on the controller side, thereby improving the consistency between the machining trajectory and the dwell control.

[0017] (4) By correcting the target removal distribution or residence time series of the next process based on the actual removal distribution, the process drift can be corrected in a closed loop, thereby improving the processing convergence and reducing the risk of overcutting. Attached Figure Description

[0018] Figure 1 This is a general block diagram of the planar finishing and machining system.

[0019] Figure 2 This is a schematic diagram of a planar finishing system.

[0020] Figure 3 This is a schematic diagram of the substrate mounting.

[0021] Figure 4 This is a schematic diagram of the calibration component structure.

[0022] Figure 5 This is a schematic diagram of in-situ leveling, workstation switching compensation, and processing flow.

[0023] Figures 6-9 This is a schematic diagram of the mapping relationship between two-layer electronic cams.

[0024] Figure 10 This is a schematic diagram of a spiral-like covering trajectory and tool entry point.

[0025] Figure 11 This is a schematic diagram of the residence time field distribution.

[0026] Figure 12 A schematic diagram illustrating the calibration and inverse calculation of "residence time - removal amount".

[0027] Figure 13 This is a schematic diagram of the closed-loop update process for flipping and retesting.

[0028] Figure 14 This is a rendering of the measurement data from the host computer's substrate.

[0029] Figure 15 Rendering of the workpiece measurement on the host computer (before leveling).

[0030] Figure 16 Render the workpiece measurement image (after leveling) for the host computer.

[0031] Figure 17 This is a rendering of the host computer's main control interface.

[0032] Figure 18 This is the control panel for process parameters on the host computer.

[0033] Reference numerals: 100 Measurement station; 110 In-situ measurement sensor; 120 Attitude adjustment mechanism; 200 Machining station; 210 Machining tool; 220 Machining motion platform; 230 Force control module; 300 Station switching mechanism; 310 Calibration base plate; 320 Base plate calibration assembly; 321 Base plate; 322 Guide rod and mounting base; 323 Elbow clamp push-pull type clamp; 324 Push plate; 325 Pressure plate; 326 Universal foot cup; 327 Level adjuster; 400 Host computer; 500 Control unit; 510 First-layer electronic cam; 520 Second-layer electronic cam; 530 Virtual time axis; 540 Virtual angle axis; 551 First real axis; 552 Second real axis; 560 Station switching compensation parameter set; 570 Remove model library; 600 Parameters and model. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] To facilitate the description of control relationships, the following conventions are used for the symbols in this invention: residence time is represented by t; single-cycle discrete residence time series is represented by t i The symbol represents the angle segment number; the virtual angle is represented by θ; and the total period of a single lap is represented by T. cycle The target removal amount is represented by Δh.

[0036] like Figure 1 , 2 As shown, the planar finishing machining system of the present invention includes a measuring station 100, a machining station 200, a station switching mechanism 300, a host computer 400, a control unit 500, and a workpiece-related clamping and posture adjustment mechanism 120. The measuring station 100 is used for on-machine measurement and output of thickness and surface shape data; the machining station 200 is used to drive the machining tool 210 to move relative to the workpiece under the action of the machining motion platform 220 and perform force-controlled machining; the station switching mechanism 300 is used to switch the workpiece between the measuring station 100 and the machining station 200.

[0037] In a preferred embodiment, the measuring station 100 is arranged on the left side of the machine tool and the machining station 200 is arranged on the right side of the machine tool; however, the present invention is not limited to the left-right arrangement, but can also be arranged in front-back or a switchable station structure achieved by rotation.

[0038] Furthermore, the positional difference between the two workstations mainly originates from machine tool installation errors, guide rail straightness errors, repeatability errors of the transfer mechanism, and tooling clamping errors. In a preferred embodiment, after the machine tool is installed, a positional difference calibration between the two workstations is first performed: the calibration substrate 310 is installed at the workpiece installation position, and in-situ measurements or contact alignment are performed on the calibration substrate 310 at the measurement station 100 and the machining station 200, respectively, to obtain the planar parameters or reference point coordinates of the calibration substrate at the two workstations.

[0039] like Figure 3 , 4 As shown, to improve the positioning consistency of the calibration substrate 310 during repeated clamping between the measurement station 100 and the machining station 200, this embodiment provides a substrate calibration assembly 320. The substrate calibration assembly 320 is used to quickly install the calibration substrate 310 onto the machine tool's mounting bridge or equivalent mounting base, and provides guiding limits, multi-point support, and horizontal adjustment to reduce the calibration error between the two stations caused by clamping repeatability, structural jamming, or self-weight deflection.

[0040] The substrate calibration assembly 320 includes: a base plate 321, a guide rod and mounting base 322, an elbow-type push-pull clamp 323, a push plate 324, a pressure plate 325, a universal foot cup 326, and a leveling device 327. The base plate 321 serves as the mounting reference for all components, and the pressure plate 325 is fixedly mounted on it. The elbow-type push-pull clamp 323 is used to clamp and fix the entire substrate calibration assembly 320 onto the mounting bridge plate. The elbow-type push-pull clamp 323 employs the dead-point self-locking principle of a mechanical four-bar linkage to achieve rapid clamping and rapid opening. The push plate 324 is installed at the working end of the elbow-type push-pull clamp 323 to increase the contact area with the mounting bridge plate or clamping surface and to uniformly transmit the clamping force.

[0041] The guide rod and mounting base 322 include at least two parallel guide rods for guiding and constraining the movement of the push plate 324 to prevent lateral swaying of the push plate 324 from causing structural jamming, thereby improving the repeatability and stability of the clamping action; the pressure plate 325 is fixed on the base plate 321 and cooperates with the push plate 324 to clamp and limit the calibration substrate 310, so that the calibration substrate 310 is stable in the clamped state; the universal foot cup 326 is set below the base plate 321 or below the calibration substrate 310, providing adjustable support to counteract the deformation of the base plate 321 caused by its own weight and reduce the deflection of the calibration substrate 310; the level adjuster 327 is set in multiple parts and distributed at the four corners or circumferential positions of the base plate 321, for multi-point fine adjustment of the height of the calibration substrate 310 to achieve level adjustment.

[0042] In a preferred adjustment process: first, loosen the fixing bolts of the calibration substrate 310, and place a high-precision level on the calibration substrate 310; then, adjust multiple level adjusters 327 respectively to center the level bubble or meet the preset level threshold; finally, tighten the fixing bolts of the calibration substrate 310 to complete the leveling. Through the above structure and process, the same calibration substrate 310 can be repeatedly clamped at two stations to obtain a stable and consistent reference plane, thereby improving the calibration and compensation effect of the position difference parameters between the two stations.

[0043] Based on the planar parameters or reference point coordinates measured at the two workstations, calculate the positional difference parameters between the measurement workstation coordinate system and the machining workstation coordinate system. The positional difference parameters include at least the tilt compensation and translation compensation around two orthogonal directions. Write the positional difference parameters into the workstation switching compensation parameter set for use when switching workstations.

[0044] When compensating for workstation switching, the system can use any of the following methods:

[0045] (a) Posture compensation method: After the workpiece is switched from the measurement station 100 to the processing station 200, the control unit 500 calls the position difference parameter to drive the posture adjustment mechanism 120 to compensate for the posture of the workpiece, so that the posture of the workpiece is restored to the equivalent posture after the measurement station is leveled.

[0046] (b) Coordinate compensation method: The control unit 500 calls the position difference parameter to perform coordinate transformation compensation on the motion command of the machining station 200, so that the machining trajectory is equivalent to the trajectory planned in the measurement station coordinate system under the machining station coordinate system.

[0047] Positional error calibration can be performed after machine tool installation, relocation, or maintenance, or it can be reviewed and updated according to a preset cycle to improve long-term stability.

[0048] like Figure 14 As shown, when the calibration substrate 310 is at the measurement station 100 and the processing station 200 respectively, the host computer measures the surface of the calibration substrate and generates a rendering of the substrate surface and its annular unfolding result. By comparing the measurement results of the reference plane of the calibration substrate at the two stations, the planar parameters or reference point coordinate differences of the calibration substrate at different stations can be extracted, thereby calculating the pose difference parameters between the two stations. Tables 1 and 2 show the pose difference parameters calculated by the host computer. The pose difference parameters may include tilt compensation and translation compensation, and are used as input parameters for station switching compensation. Based on the pose difference parameters in Tables 1 and 2, the control unit compensates for the posture or coordinates when the workpiece switches from the measurement station to the processing station, so that the execution reference at the processing station is consistent with the measurement reference at the measurement station.

[0049] Table 1. Position and orientation difference parameters (tilt compensation)

[0050]

[0051] Table 2 Position and orientation difference parameters (translation compensation)

[0052]

[0053] like Figure 5As shown, after the workpiece is clamped, in-situ measurement and leveling are performed at the measurement station 100. Measurement can be performed using a line laser sensor 110, a contact probe, or a profilometer, etc. In a preferred embodiment, a line laser sensor 110 is used to acquire the height sequence or two-dimensional height matrix of the workpiece's surface to be machined.

[0054] During leveling, at least three discrete measurement points can be selected on the surface to be processed for plane fitting to obtain the tilt plane parameters of the surface to be processed. Based on this, the tilt angle components around two orthogonal directions are calculated, and the attitude adjustment mechanism 120 is driven to perform attitude compensation. After leveling, a rapid retest can be performed. If the residual attitude error is greater than the threshold, the compensation amount is updated and leveling is performed again until the residual attitude error is less than the threshold.

[0055] like Figure 15 and Figure 16 As shown, the surface stitching diagram, toroidal stitching diagram, and top view of the workpiece surface to be machined before leveling all reflect a certain degree of posture skewness and uneven height distribution. In this state, direct finishing processing can easily lead to localized deviations in the amount of material removed from the target value. After leveling by the posture adjustment mechanism 120, the overall posture of the workpiece surface to be machined is corrected. The surface stitching diagram and toroidal stitching diagram after leveling show that the tilting trend of the surface to be machined relative to the machine tool reference is weakened, and the geometric positional relationship corresponding to the top view also tends to stabilize. The measurement results before and after leveling are used to verify the effect of posture adjustment and to provide a measurement basis for determining the subsequent target amount of material removed.

[0056] V. Dual-layer electronic cam virtual axis modulation and spiral trajectory execution

[0057] like Figures 6-9 As shown, this invention employs a dual-layer electronic cam (or an equivalent dual-layer mapping) to achieve explicit controllability of dwell time: the first-layer electronic cam uses the virtual time axis 530 as the master axis and the virtual angle axis 540 as the slave axis; the second-layer electronic cam uses the virtual angle axis 540 as the master axis and two real axes 551 and 552 as slave axes, its function being to map the virtual angle into the position output of the two real axes, thereby forming a circular interpolation trajectory on the workpiece surface. By modulating the time allocation through the first-layer electronic cam and mapping the spatial trajectory through the second-layer electronic cam, this invention achieves dwell time control and geometric trajectory execution in layers, thereby improving the consistency between dwell control and trajectory execution.

[0058] The first-layer electronic cam is used to convert the discrete dwell time sequence sent by the host computer into a "time-angle" relationship: a circle is divided into several angle segments, a dwell time is assigned to each angle segment, and a cam curve is generated between the time virtual axis position and the virtual angle axis angle, so that the angular velocity of the virtual angle axis changes with the dwell time sequence, thereby changing the execution time of each angle segment while keeping the angle segment order unchanged.

[0059] The second-layer electronic cam is used to map the virtual angle to the positions of two real axes, thereby forming a circular interpolation trajectory. The two real axes can be orthogonal linear axes, dual-drive linear axes, or equivalent two-dimensional motion axis systems; their spatial mapping is obtained through tool setting and calibration. Under the action of the force control module 230, the two real axes realize the normal constant force or constant pressure control of the machining tool 210 on the workpiece.

[0060] like Figure 10 As shown, the machining trajectory of this invention is a spiral-like covering trajectory: after each complete circular interpolation, a feed is performed at a preset infeed position, causing the trajectory radius or relative center offset of the next circular interpolation to change, thereby forming a spiral scan covering the machining area by multiple overlapping cycles. The feed distance and number of operations are issued by the host computer.

[0061] The tool infeed position can be defined by angle or by workpiece coordinates. Table 3 provides an example mapping of a tool infeed angle to its corresponding two-dimensional coordinates (this is only for illustrating the tool infeed description method; actual values ​​will vary depending on the machine tool calibration).

[0062] Table 3 Mapping Table

[0063]

[0064] As can be seen from Table 3, which shows the corresponding two-dimensional coordinates of the feed position angle, the preset feed position can be represented by either an angle parameter or the two-dimensional position coordinates of the first and second real axes. After completing each circular interpolation cycle, the control unit can move the two real axes to the preset feed position according to the feed position definition before executing the next feed action. By uniformly representing the feed position as an angle or two-dimensional coordinates, the circular trajectory output by the second-layer electronic cam can be kept consistent with each feed action, thus forming a continuous spiral-like covering trajectory. It should be noted that the coordinate values ​​in the table should be derived from the tool setting and calibration results. Before submission, each value should be checked against the original calibration record to ensure the accuracy of the numerical format and decimal places.

[0065] After completing a preset number of operations, the workpiece is flipped over and returned to the measurement station for remeasurement to obtain the actual removal amount distribution after this round of processing. The control unit or host computer compares the actual removal amount distribution of this round with the target removal amount distribution of this round to obtain the residual distribution, and uses this to correct the target removal amount distribution or residence time series of the next process. When the results of multiple consecutive processing rounds show deviations in the same direction, the removal rate parameters in the removal model library can be further corrected. Through the above closed-loop correction, the processing error can be reduced round by round, the processing convergence can be improved, and the risk of overcutting can be reduced.

[0066] In a preferred control implementation, the control unit 500 uses a PLC with electronic cam function to implement a double-layer electronic cam. The electronic cam can be loaded and run through function blocks such as cam table selection, cam entry and cam exit. Alternatively, equivalent double-layer mapping control can be achieved by using time scheduling interpolation of a CNC system (such as PVT interpolation), motion control card or industrial PC soft PLC.

[0067] like Figure 12 As shown, residence time planning is predicated on understanding the material removal capacity under given process parameters. For example... Figure 11 , 12 As shown, this invention establishes a "dwelling time-removal amount" mapping model through fixed-point dwell calibration: in force control mode, the normal load is set so that the processing tool stays at the selected position for a preset time, the height difference before and after processing is recorded to obtain the removal amount, and a removal model library is formed under different grinding head materials, particle sizes, normal loads and speeds.

[0068] Table 4 provides example data on the fixed-point retention removal amount and average removal rate of different grinding head materials and particle sizes under 45N force control (this is only for illustrating the calibration method; the actual values ​​vary with process conditions).

[0069] Table 4 Fixed-point residence process data table

[0070]

[0071] Table 4 shows that under the same force-controlled load of 45N, the removal capacity varies significantly depending on the material and particle size of the grinding head. Taking the cubic boron nitride grinding head as an example, the removal amount after 4 min 30 s is 0.51 mm when the particle size is 150, with an average removal rate of 0.113333 mm / min; the removal amount after 400 is 0.23 mm when the particle size is 400, with an average removal rate of 0.051111 mm / min. Both are significantly higher than the removal amounts after 10 min of resin diamond grinding head and electroplated diamond grinding head. The material removal amounts for resin-bonded diamond grinding heads with grit sizes of 150 and 400 were 0.016 mm and 0.009 mm, respectively; for electroplated diamond grinding heads with grit sizes of 150 and 400, the removal amounts were 0.0078 mm and 0.0017 mm, respectively; for sintered diamond grinding heads with grit sizes of 100 and 200, the removal amounts were 0.0113 mm and 0.0073 mm, respectively; while the removal amount for silicon carbide grinding heads under the test conditions given in Table 2 was 0. These data indicate that there are significant differences in material removal capabilities under different process parameters. Therefore, it is necessary to establish corresponding residence time-removal amount mapping models for different grinding head materials, grit sizes, and load conditions, and store them in a removal model library for use when subsequently using residence time to deduce the target removal amount.

[0072] Table 5. Dwell time schedule data obtained from backpropagation by the host computer.

[0073]

[0074] The dwell time schedule data obtained from the host computer shows that the target removal amount varies for each angle segment, and the allocated dwell time also changes accordingly. For example, at the corresponding angle of 0°, the target removal amount is 0.0429, and the allocated dwell time is 2.774; at the corresponding angle of 9°, the target removal amount increases to 0.0543, and the allocated dwell time increases to 3.459; at the corresponding angle of 360°, both the target removal amount and the dwell time return to 0, indicating that the dwell time sequence has completed one closed loop. The cumulative time in the dwell time schedule reaches 906.166 at 360°, indicating that the total dwell time for this single-loop processing is 906.166. The above results demonstrate that the present invention can allocate different dwell times to different positions within a single loop according to the differences in target removal amounts for different angle segments, thereby achieving deterministic trimming control with longer dwell times for thicker areas and shorter dwell times for thinner areas.

[0075] When calculating the residence time, the host computer generates a target removal amount distribution based on the measured thickness and surface deviation: thicker areas correspond to larger target removal amounts, and thinner areas correspond to smaller target removal amounts. Based on the mapping relationship of the removal model library under the corresponding process parameter identifiers, the target removal amount is then calculated into a discrete residence time series. This calculation can be achieved using table lookup, piecewise linear interpolation, or a fitting function.

[0076] To ensure safety and rhythm, this invention imposes constraints on dwell time: each discrete dwell time is not less than 0.5s, and a preset total cycle constraint is applied to the dwell time sequence within the same loop. Preferably, a minimum dwell time constraint is first applied to the initial dwell time sequence, and then, without violating the minimum dwell time constraint, the sequence is scaled proportionally or the remaining time is redistributed so that the sum of the normalized dwell time sequence equals the preset total cycle. For example, if the sum of the discrete dwell time sequence obtained from the initial back-calculation is 920s, and the preset total cycle is 900s, then all angle segments with dwell times not less than the minimum dwell time are retained first, and only the angle segments with dwell times greater than the minimum dwell time are proportionally reduced to ensure that the adjusted sum of the dwell time within a single loop meets 900s; if the sum of the discrete dwell time sequence obtained from the initial back-calculation is 880s, then the remaining 20s can be distributed to each angle segment according to the proportion of the initial dwell time of each angle segment or the proportion of the target removal amount, so that the adjusted sum of the dwell time within a single loop meets the preset total cycle. By applying the above constraints, the dwell time series can simultaneously meet both safety and rhythm requirements without altering the relative magnitude of dwell time at each angle segment.

[0077] To reduce acceleration abrupt changes and suppress vibration in the electronic cam curve, it is preferable to perform smoothing on the normalized dwell time series. The smoothing can be at least one of moving average, finite impulse response filtering, or spline interpolation. Furthermore, upper limits can be set for the maximum angular velocity and maximum angular acceleration of the virtual angle axis. When the dwell time series causes the angular velocity or angular acceleration to exceed the limit, dynamic constraints are satisfied through amplitude limiting and renormalization.

[0078] VII. Flip-over retesting and closed-loop update

[0079] like Figure 13 As shown, after completing the preset number of processes, the system flips the workpiece and sends it back to the measurement station 100 for re-measurement, obtains the surface morphology data after processing, and compares it with the measurement results before processing to obtain the actual removal amount distribution of this round of processing; at the same time, the residual sum of squares or other error evaluation indicators can be calculated based on the difference between the target removal amount distribution and the actual removal amount distribution to characterize the processing convergence status of the current process.

[0080] like Figure 17 As shown, the host computer's central control interface is used to uniformly display the operating status of the measurement unit, processing unit, workstation switching mechanism, and control unit, and serves as the central control entry point for the closed-loop update of the flipping retest. After completing the flipping retest, the host computer receives and displays the measurement results, processing status, and error evaluation results of the current process in the central control interface. Simultaneously, it invokes the closed-loop update logic to compare the actual removal amount distribution with the target removal amount distribution in this round, and then proceeds to the next round of parameter correction and process decision-making.

[0081] like Figure 18 As shown, the host computer's process parameter control panel is used to set the measurement and process parameters after the closed-loop update. Figure 13 The closed-loop process shown allows for adjustments to parameters such as the number of measurement steps, trigger position, Z-axis feed, and starting position in the process parameter control panel after calculating the actual removal distribution and residual evaluation results. Furthermore, it provides parameter input for the next round of retesting and the generation of the next residence time series by sending measurement tables, single-loop measurements, or equivalent control commands. Figure 18 The process parameter control panel shown constitutes Figure 13 The parameter landing interface for "generating the next round of residence schedule and entering the next round of processing" in the middle.

[0082] The host computer updates the "residence time-removal amount" mapping model based on the actual removal amount distribution in this round. This update may include at least one of the following: removal rate gain update, relaxation factor update, residence time limiting, and smoothing constraint, to avoid over-shearing and oscillations. Then, it re-calculates the residence time series for the next round based on the updated model. Figure 13If the determination result shows that the processing indicators have not yet been met, the host computer generates the next round of dwell time schedule and enters the next round of processing; when the determination result shows that the processing indicators have been met, the closed-loop update process ends. Through the above closed-loop update mechanism, the processing error can be reduced round by round, and the processing convergence can be improved.

[0083] In one alternative implementation, one or more flipping and retesting and parameter updates can be performed after each round of processing until the surface shape error, thickness error or other processing indicators meet the preset requirements.

[0084] VIII. Optional Implementations and Equivalent Replacements

[0085] The method and system of this invention are not limited to a specific machine tool model or a specific mechanical structure. The measuring station 100 and the machining station 200 can be set in different positions on the same frame, or the same station can be switched between measurement and machining by rotation / transfer; the in-situ measuring sensor can be a line laser sensor, a contact probe, or a profilometer, etc.; the control unit 500 can be a PLC, a CNC system, a motion control card, or an industrial PC soft PLC.

[0086] Without departing from the core idea of ​​this invention, the implementation of the first-layer electronic cam and the second-layer electronic cam can be replaced by an equivalent time-angle-two-dimensional position mapping. For example, a speed planning with time calibration and an interpolator can be used to realize the speed scheduling of virtual angles, and then the interpolator drives the two real axes to form a circular interpolation trajectory. The above equivalent substitution is still within the protection scope of this invention.

Claims

1. A dual-station planar finishing process, characterized in that, include: The positional difference parameters between the measurement station and the machining station are calibrated based on the calibration substrate, and the positional difference parameters are called for compensation when the workpiece switches from the measurement station to the machining station. The target removal amount distribution is determined according to the measurement results of the surface to be machined, and a dwell time sequence constrained by the minimum dwell time and the total cycle of a single circle is generated by combining the pre-established dwell time-removal amount mapping model. The single circle is the machining process corresponding to the completion of one closed loop of the virtual angle axis. The control unit establishes a double-layer electronic cam or equivalent double-layer mapping relationship according to the dwell time sequence. The first layer uses the time virtual axis as the master axis and the virtual angle axis as the slave axis. The second layer uses the virtual angle axis as the master axis and two real axes as slave axes, driving the two real axes to perform circular interpolation. When the preset infeed position is reached in each circle, the feed is fed at a given feed distance to form a spiral-like covering trajectory. After machining, the target removal amount distribution or dwell time sequence of the next process is corrected according to the actual removal amount distribution.

2. The method according to claim 1, characterized in that, The position difference parameter includes at least the tilt compensation and translation compensation between the measurement station and the machining station.

3. The method according to claim 1, characterized in that, The calibration substrate is supported and leveled by a substrate calibration assembly, which includes a base plate, guide rods and mounting base, elbow-type push-pull clamps, push plate, pressure plate, universal feet and level adjuster.

4. The method according to claim 3, characterized in that, The elbow-type push-pull clamp uses the dead-point self-locking principle of a mechanical four-bar linkage to achieve rapid clamping and rapid opening; the guide rod and mounting base are used to guide the push plate to prevent lateral swaying and jamming; the universal feet are used to support and reduce the deformation of the base plate or calibration substrate due to its own weight; the level adjuster is used to make multi-point fine adjustments to the calibration substrate.

5. The method according to claim 1, characterized in that, The residence time-removal amount mapping model is established through fixed-point residence calibration and stored in the removal model library.

6. The method according to claim 1, characterized in that, When the theoretical dwell time corresponding to a certain angle segment is greater than the preset maximum dwell time, the dwell time of that angle segment in this round is limited to the maximum dwell time, and the remaining target removal amount that was not completed in this round of that angle segment is incorporated into the subsequent process for recalculation.

7. The method according to claim 1, characterized in that, When the total dwell time of a single lap after applying the minimum dwell time constraint deviates from the preset total cycle, the angle segments with dwell times greater than the minimum dwell time are adjusted proportionally, or the remaining time is allocated according to the preset weight, so that the adjusted total dwell time of a single lap meets the preset total cycle.

8. The method according to claim 7, characterized in that, Smoothing is performed on the dwell time series after adjustment for total period constraints to limit the rate of change of dwell time between adjacent angle segments.

9. The method according to claim 1, characterized in that, When generating the first layer of electronic cam curve, the maximum angular velocity and maximum angular acceleration constraints are applied to the virtual angle axis; when the dwell time series causes the angular velocity or angular acceleration to exceed the limit, the dwell time series is adjusted by limiting the amplitude and the total period constraint.

10. A dual-station planar finishing system, characterized in that, This system is used to implement the method as described in any one of claims 1-9, comprising a measurement unit, a processing unit, a station switching mechanism, a calibration substrate, a substrate calibration component, a control unit, a station switching compensation parameter set, and a removal model library; wherein, the station switching compensation parameter set is used to store the pose difference parameters between the measurement station and the processing station, and the removal model library is used to store the dwell time-removal amount mapping model; the control unit is used to call the pose difference parameters for compensation when the workpiece switches from the measurement station to the processing station, and to establish a double-layer electronic cam or an equivalent double-layer mapping relationship based on the dwell time sequence, wherein the first layer is used to realize the mapping from the time virtual axis to the virtual angle axis, and the second layer is used to realize the mapping from the virtual angle axis to two real axes, so as to drive the two real axes to perform circular interpolation and feed at a preset infeed position to form a spiral-like covering trajectory; the station switching compensation parameter set is used to store the pose difference parameters, and the removal model library is used to store the dwell time-removal amount mapping model, and the two are stored independently of each other.

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