A lens taking method and system based on a general algorithm of lens mold cavity coordinates

Abstract

The present application relates to the technical field of optical lens manufacturing, and provides a lens taking method and system based on a general algorithm of lens mold cavity coordinates. The method comprises the following steps: establishing a mechanical coordinate system and taking the mold center fixed on a tool as the origin of the mold coordinate system, obtaining the offset of the mold center in the mechanical coordinate system as the center offset, setting the number of mold cavities N, the mold base ring radius R and the first cavity offset angle θ1, and setting the taking sequence of the cavity number counterclockwise / clockwise, calculating the two-dimensional coordinates under the mold coordinate system for the kth mold cavity, performing a homogeneous translation on the two-dimensional coordinates and the center offset to obtain the target grabbing point under the mechanical coordinate system, grabbing the lens mold cavity at the target grabbing point, and repeating the taking value k from 1 to N to complete the cavity-by-cavity taking of the lenses in the counterclockwise / clockwise taking sequence of the optical lens production mold. The method of the present application can be used for taking lenses from annular multi-cavity molds, and meets the actual needs of high yield, low breakage rate and fast changeover in lens production.

Description

Technical Field

[0001] This invention relates to the technical fields of optical lens manufacturing, electronic digital data processing, and design automation models, and in particular to a lens retrieval method and system based on a general algorithm for lens cavity coordinates. Background Technology

[0002] With the increasing demands for lens production capacity and consistency in applications such as mobile phone cameras, AR / VR, and automotive optics, production lines commonly adopt multi-cavity circular arrangements to increase the output per unit cycle. The use of robotic arms to achieve fast, stable, and low-breakage lens retrieval from each cavity has become a key aspect of process cycle time and yield. Existing production lines primarily employ the following methods for cavity positioning and lens retrieval: First, a fixed-point scheme based on teaching / coordinate tables, where machine operators teach each cavity and generate a fixed coordinate table; second, a mechanical limiting scheme based on fixture positioning pins or keyways, using an "anti-rotation structure + positioning pin" to limit the clamping posture; and third, a camera-guided scheme relying on visual markers (such as reference points, QR codes, or character engravings). While these methods can complete lens retrieval, issues such as coordinate offset, incorrect cavity placement / retrieval, and conservative path planning leading to limited cycle time often arise due to frequent switching between multiple specifications, minor tooling clamping errors, dimensional / deformation drift caused by mold temperature, and interference factors such as light reflection. The geometric characteristics of multi-cavity annular molds determine that the lens retrieval coordinates are not only related to the radius of the mold core ring and the number of cavities, but also strongly dependent on the angular reference of the first cavity and the increasing direction of the cavity number (clockwise / counterclockwise). In actual production, the clamping posture of the mold relative to the mechanical coordinate system often experiences slight deflections and center offsets due to fixture clearance, wear of positioning surfaces, or tooling changes. If a static coordinate table or a single point is still used as the zero point, it is easy to form a superposition of systematic angular errors and center deviations, leading to interference between the end effector and the mold wall, and the clamping position deviating from the lens's center of gravity, thus increasing the risk of breakage. To improve positioning accuracy, some solutions perform a one-time calibration after machine startup or mold change, such as using single-point alignment or two-point alignment to estimate the mold angle and center. However, lens molds are usually distributed in annular shapes, and single / double-point calibration is insufficient for the coupled estimation of the center and angle, and cannot effectively quantify the fixture eccentricity and angular drift. When temperature drift or repeated clamping causes the deviation to reappear, a lot of manual fine-tuning is still required, resulting in long changeover times and high machine setup costs. Furthermore, the combinations of the number of cavities N, the radius R of the mold core ring, and the offset angle of the first cavity vary significantly between different products and molds. Without a unified parametric coordinate generation mechanism, companies often maintain multiple coordinate tables or program branches, resulting in severe software asset fragmentation. This easily leads to basic errors such as version management mistakes, parameter input omissions, and misuse of angle units (degrees / radians), further amplifying the maintainability and traceability challenges in human-machine collaboration. On the other hand, cycle time and yield also depend on the sequential planning of the lens-grabbing path. When it is impossible to stably reproduce the cavity coordinates in both clockwise and counterclockwise directions, it becomes difficult to flexibly choose the shortest stroke grabbing sequence and avoidance strategy, often forcing the adoption of conservative paths, resulting in increased idle strokes and limited cycle time.

[0003] In summary, existing technologies generally suffer from problems such as inconsistent coordinate system definitions, difficulty in stably determining the zero angle position, difficulty in robustly estimating the center offset online, poor multi-mode versatility and high software maintenance costs due to insufficient parameterization, and difficulty in balancing forward / reverse sequence number optimization with production cycle time optimization. These issues make it difficult to meet the actual needs of high yield, low breakage rate, and rapid changeover. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a lens retrieval method and system based on a general algorithm for lens mold cavity coordinates. This method can be applied to lens retrieval from annular multi-cavity molds, meeting the practical requirements of high yield, low breakage rate, and rapid mold changeover.

[0005] In a first aspect, the present invention provides a lens retrieval method based on a general algorithm for lens mold cavity coordinates, comprising:

[0006] Automatically identify the anti-rotation plane of the optical lens production mold to fix the position of the mold, establish a mechanical coordinate system and take the center of the mold fixed on the tooling as the origin of the mold coordinate system;

[0007] The offset of the mold center in the mechanical coordinate system is obtained by the three-point circle determination method and used as the center offset. The number of mold cavities N, the radius of the mold core ring R and the first cavity deflection angle θ1 are set, and the mirror taking order of the cavity number is set to counterclockwise or clockwise.

[0008] When selecting the acupoint number counterclockwise, calculate the two-dimensional coordinates in the mold coordinate system for the kth acupoint: Xk=R×cos〔θ1+(k-1) / N×360°〕,Yk=R×sin〔θ1+(k-1) / N×360°〕;

[0009] When selecting the acupoint number clockwise, calculate the two-dimensional coordinates in the mold coordinate system for the k-th acupoint: Xk=R×cos〔θ1-(k-1) / N×360°〕,Yk=R×sin〔θ1-(k-1) / N×360°〕; perform homogeneous translation of (Xk,Yk) with the center offset to obtain the target grasping point (Xk′,Yk′) in the mechanical coordinate system;

[0010] The lens-retrieving robot is controlled to move to the target grasping point (Xk′, Yk′) to grasp the lens mold cavity. The value of k is 1 to N in a cycle to complete the removal of the lens cavity one by one in the clockwise or counterclockwise lens-retrieving sequence of the entire optical lens production mold.

[0011] Secondly, the present invention provides a lens retrieval system based on a general algorithm for lens mold cavity coordinates, wherein the lens retrieval system uses the above-mentioned lens retrieval method based on the general algorithm for lens mold cavity coordinates to grasp the lens in the lens mold cavity.

[0012] Compared with the prior art, the beneficial effects of this invention are as follows:

[0013] This invention provides a lens retrieval method and system based on a general algorithm for lens mold cavity coordinates. The method includes: automatically identifying the anti-rotation plane of the optical lens production mold to fix the mold's position; establishing a mechanical coordinate system and using the mold's center, fixed on the tooling, as the origin of the mold coordinate system; obtaining the offset of the mold's center in the mechanical coordinate system using a three-point circle determination method as the center offset; setting the number of mold cavities N, the radius R of the mold core ring, and the first cavity's deflection angle θ1; and setting the lens retrieval order for either counter-clockwise or clockwise cavity numbering; when counter-clockwise cavity numbering is selected, calculating the two-dimensional coordinates in the mold coordinate system for the k-th cavity: Xk = R × cos[θ1 + (k - 1) / N × 360°], Yk = R × sin[θ1 + (k - 1) / N × 360°], Yk = R × sin[θ1 + (k - 1) / N × 360°]. / N×360°〕; When selecting the cavity number clockwise, calculate the two-dimensional coordinates in the mold coordinate system for the k-th cavity: Xk=R×cos〔θ1-(k-1) / N×360°〕, Yk=R×sin〔θ1-(k-1) / N×360°〕; Perform homogeneous translation of (Xk, Yk) with the center offset to obtain the target grasping point (Xk′, Yk′) in the mechanical coordinate system; Control the lens-retrieving robot to move to the target grasping point (Xk′, Yk′) to grasp the lens cavity, and cycle the value of k from 1 to N to complete the cavity-by-cavity lens retrieval of the entire optical lens production mold in either a clockwise or counterclockwise lens retrieval sequence. The method of the present invention can be applied to lens retrieval from annular multi-cavity molds, meeting the actual needs of high yield, low breakage rate and rapid changeover in lens production. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation thereof. Some specific embodiments of the invention will be described in detail below with reference to the accompanying drawings in an exemplary and non-limiting manner. The same reference numerals in the drawings designate the same or similar parts or components. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the drawings:

[0015] Figure 1 This is a schematic flowchart of a lens retrieval method based on a general algorithm for lens cavity coordinates according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram illustrating the positional state between the optical lens production mold and the positioning cylinder in an embodiment of the present invention.

[0017] Figure 3 This is a schematic diagram of the positional state of the double anti-rotation plane 6-cavity mold relative to the edge measuring points during rotation, according to an embodiment of the present invention.

[0018] Figure 4 This is a schematic diagram showing another positional state of the double anti-rotation plane 6-cavity mold relative to the edge measuring points during rotation, according to an embodiment of the present invention.

[0019] Figure 5 This is a schematic diagram showing another positional state of the double-anti-rotation plane 6-cavity mold relative to the edge measuring points during rotation, according to an embodiment of the present invention.

[0020] Figure 6 This is a schematic diagram of another positional state of the double anti-rotation plane 6-cavity mold relative to the edge measuring point during rotation, according to an embodiment of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] See Figures 1-6 This invention provides a lens retrieval method based on a general algorithm for lens mold cavity coordinates. This method can be used in a lens retrieval system based on a general algorithm for lens mold cavity coordinates. The method includes the following steps:

[0023] S101. Automatically identify the anti-rotation plane of the optical lens production mold to fix the position of the mold, establish a mechanical coordinate system and take the center of the mold fixed on the tooling as the origin of the mold coordinate system;

[0024] S102. Obtain the offset of the mold center in the mechanical coordinate system by using the three-point circle determination method as the center offset. Set the number of mold cavities N, the radius of the mold core ring R, and the first cavity deflection angle θ1. Set the mirror taking order of the cavity number counterclockwise or clockwise.

[0025] S103. When the selected acupoint number is counterclockwise, calculate the two-dimensional coordinates of the k-th acupoint in the mold coordinate system: Xk=R×cos〔θ1+(k-1) / N×360°〕,Yk=R×sin〔θ1+(k-1) / N×360°〕;

[0026] S104. When the selected cavity number is clockwise, calculate the two-dimensional coordinates in the mold coordinate system for the kth cavity: Xk=R×cos〔θ1-(k-1) / N×360°〕,Yk=R×sin〔θ1-(k-1) / N×360°〕; Perform homogeneous translation of (Xk,Yk) with the center offset to obtain the target grasping point (Xk′,Yk′) in the mechanical coordinate system;

[0027] S105. Control the lens-retrieving robot arm to move to the target grasping point (Xk′, Yk′) to grasp the lens mold cavity. The value of k is 1 to N to complete the removal of the lens cavity by cavity in the clockwise or counterclockwise lens-retrieving sequence of the entire optical lens production mold.

[0028] Preferably, when fixing the position of the mold, it can be positioned by a combination of a main positioning cylinder and a secondary positioning cylinder; the number of mold cavities N=6, the radius of the mold core ring R=15, and the deflection angle θ1 of the first cavity=240°.

[0029] In this embodiment, automatically identifying the mold's anti-rotation plane, fixing the clamping posture, establishing a mechanical coordinate system, and setting the mold's center as the origin of the mold coordinate system can solve the problems of unstable angle zero position, inconsistent coordinate system definition, and angle drift caused by random clamping. This achieves a stable angle reference and a unified coordinate caliber, avoiding confusion between clockwise and counterclockwise sequence numbers and incorrect placement / removal of cavities. Using a three-point circle determination to obtain the offset of the mold's center in the mechanical coordinate system solves the problems of insufficient angle coupling estimation of the center in single / double-point calibration, and the inability to compensate for clamping eccentricity and temperature drift. This achieves robust estimation and online compensation for center offset, reducing reliance on manual teaching and repeated fine-tuning. Parameterizing the number of cavities N, the radius R of the mold core ring, and the first cavity offset angle θ1, and selecting the cavity sequence direction (counterclockwise / clockwise), solves the problems of poor cross-mold versatility, multiple versions of coordinate tables, and inconsistent angle units and direction calibers. This enables universal coordinate generation and rapid model change driven by a small number of parameters. The formulas for calculating the counter-clockwise coordinates of acupoint numbers, Xk = R × cos[θ1 + (k - 1) / N × 360°] and Yk = R × sin[θ1 + (k - 1) / N × 360°], can solve the problems of misalignment and repeated teaching caused by inconsistencies between the sequence direction and geometric calculations, achieving stable reproduction of counter-clockwise sequence coordinates consistent with the process definition. The corresponding formulas for calculating the clockwise acupoint numbers, Xk = R × cos[θ1 - (k - 1) / N × 360°] and Yk = R × sin[θ1 - (k - 1) / N × 360°], can solve the problem of needing to create a separate coordinate table or re-teach when reverse mirroring is required, achieving integrated generation and switching between clockwise and counter-clockwise sequences. By performing a homogeneous translation of (Xk, Yk) with the center offset to obtain (Xk′, Yk′) in the machine coordinate system, the problems of inconsistent mapping from mold coordinates to machine coordinates and interference between the end effector and the mold wall caused by uncompensated eccentricity can be solved. This enables accurate gripping point coordinates that can be directly sent to the robot / PLC. Controlling the robot arm to move one hole at a time according to (Xk′, Yk′) and cyclically with k ranging from 1 to N can solve the problems of time-consuming manual hole-by-hole teaching and limited cycle time due to conservative paths. This enables orderly automatic hole-by-hole lens retrieval, shortens idle travel, and improves cycle time and consistency.

[0030] It should be noted that in this embodiment, incorporating the first cavity offset angle θ1 into a unified formula as the zero angle solves the problem of unclear definition of the first cavity or difficulty in globally correcting the overall angle drift after mold change. This allows for rapid reproduction of the entire ring coordinate system by updating only θ1. Using R as a unified ring radius parameter in the calculation solves the problem that changes in ring radius caused by mold temperature / batch variation cannot be reflected in the coordinates. This allows for a one-time global correction of the radius based on the latest actual measurement or a set R, ensuring consistency between the grasping point and the actual object. Generating the entire ring coordinate system using the equiangular interval relationship between k and N solves the problems of maintaining separate coordinate tables, version bifurcation, and input errors for molds with different cavity numbers. This allows a single algorithm to cover any N ring molds, reducing maintenance costs and error rates. Overall, the method provided in this embodiment can be applied to lens retrieval from ring multi-cavity molds, meeting the practical needs of high yield, low breakage rate, and rapid changeover in lens production.

[0031] Preferably, automatically identifying the anti-rotation plane of the optical lens production mold may include the following steps:

[0032] For a cylindrical mold with one or two anti-rotation planes, a robot arm removes the mold from the molding machine and places it at the center of a rotatable boss, and sets the current angle of the boss's rotation motor to zero; a laser displacement sensor is installed above the boss along the Z-axis, and an X, Y, Z rectangular coordinate system is established with the center of the boss as the origin, and the Z-axis is made coaxial with the rotation axis of the boss.

[0033] Move the X and Y axes so that the laser displacement sensor beam is located at the edge of the mold and meets the edge measurement point. The edge measurement point is the X coordinate of the mold center in the X direction and the Y coordinate of the mold center in the Y direction plus the mold radius minus a preset distance. The preset distance is the radial inward shrinkage of the mold. Start the laser displacement sensor to collect the mold edge height H0. When H0 is within the threshold range, enter the clockwise rotation step; otherwise, enter the counterclockwise positioning step. The threshold range is the range between the upper limit height and the lower limit height of the mold.

[0034] In the counterclockwise positioning step, the boss rotary motor is driven to rotate counterclockwise until H0 enters the threshold range and stops immediately. Then, the clockwise rotation step is performed. In the clockwise rotation step, the boss rotary motor is driven to rotate clockwise. When H0 is detected to be less than the lower limit height, the current angle is recorded as R0. When H0 is detected to enter the threshold range again, the current angle is stopped immediately and recorded as R1. Then, the boss rotary motor is driven to rotate by a target angle θt equal to (R0-R1) / 2-90°.

[0035] At the target angle θt, a laser displacement sensor collects the mold edge height H1. When H1 is within the threshold range, a robot transfers the mold to a positionable base. The main positioning cylinder extends to make two high-precision rotatable bearings abut against the mold's anti-rotation plane, and the auxiliary positioning cylinder extends to make two other high-precision rotatable bearings abut against the mold's arc surface. The diameter of the main positioning cylinder is larger than that of the auxiliary positioning cylinder. When H1 is not within the threshold range, the boss rotary motor is first rotated counterclockwise by 90° to correct the angle before the transfer and positioning steps are performed.

[0036] In this embodiment, a laser displacement sensor is installed above the boss along the Z-axis. An X, Y, Z rectangular coordinate system is established with the boss center as the origin, and the Z-axis is coaxial with the boss's rotation axis. This provides a unified coordinate system and angle zero-point reference, avoiding inconsistencies in identification results across workstations and batches. It also achieves uniformity and reusability of angle and height measurements under the same reference system. The X and Y axes are moved so that the laser displacement sensor beam is located at the edge of the mold and meets the requirements of an edge measuring point. The edge measuring point is located at the X-coordinate of the mold center in the X direction and the Y-coordinate of the mold center in the Y direction plus the mold radius minus a preset distance (e.g., 1 mm). The preset distance is the radial inward reduction of the mold. The trigger position is determined by the edge measuring point, thus fixing the geometric conditions of the edge measuring point and ensuring the stability of the entry / exit determination of the effective measurement area. The laser displacement sensor is activated to acquire the mold edge height H0. When H0 is within a threshold range, a clockwise rotation step is initiated; otherwise, a counterclockwise positioning step is initiated. The threshold range is the area between the upper and lower limits of the mold height. This avoids the instability caused by relying on a single threshold, and uses a height range instead of a single-point threshold to enhance the robustness of entry / exit event triggering. In the clockwise rotation step, the boss rotation motor is driven to rotate clockwise. When H0 is detected to be less than the lower limit height, the current angle is recorded as R0. When H0 is detected to re-enter the threshold range, the rotation stops immediately and the current angle is recorded as R1. Subsequently, the boss rotation motor is driven to rotate by a target angle θt equal to (R0-R1) / 2-90°. This achieves the method of calculating the target angle based on two characteristic angle ranges, making the identified anti-rotation plane unique and repeatable. At the target angle θt, a laser displacement sensor acquires the mold edge height H1. When H1 is within the threshold range, a robotic arm transfers the mold to a positionable base. The main positioning cylinder extends to bring two high-precision rotatable bearings against the mold's anti-rotation plane, and the auxiliary positioning cylinder extends to bring two more high-precision rotatable bearings against the mold's arc surface. The main positioning cylinder has a larger diameter than the auxiliary positioning cylinder, thus distinguishing the main and auxiliary force paths. This achieves a mechanical path where the main reference is used for correction, followed by stabilization using the auxiliary reference, maintaining consistency between the identification angle and the final positioning angle. When H1 is not within the threshold range, the boss rotary motor is first rotated counterclockwise by 90° to correct the angle before performing the transfer and positioning steps. This avoids the 180° symmetry incompatibility problem between single-plane and double-plane molds, achieving unified correction and compatibility in symmetrical situations.

[0037] Preferably, with the angle of the boss rotary motor zeroed, the boss is continuously rotated counterclockwise at a fixed angular velocity and H0 is read in real time. H0 is compared with the set upper and lower limits of the mold height. If H0 enters the threshold range for the first time, the counterclockwise rotation is stopped immediately and the clockwise rotation step is started. If H0 crosses the threshold range and leaves again during the counterclockwise rotation, the counterclockwise rotation continues until it enters the threshold range again and is stopped immediately to avoid misjudgment caused by the random initial angle of the mold. The angular velocity remains constant throughout the positioning process to ensure the consistency of the angle criterion and the height criterion.

[0038] In this embodiment, with the boss rotary motor angle zeroed, the boss is continuously rotated counterclockwise at a fixed angular velocity, and H0 is read in real time. H0 is compared with the set upper and lower limits of the mold height. If H0 enters the threshold range for the first time, the counterclockwise rotation stops immediately and the clockwise rotation step begins. If H0 crosses the threshold range and leaves again during the counterclockwise rotation, the counterclockwise rotation continues until it re-enters the threshold range and stops immediately. The angular velocity remains constant throughout the positioning process, avoiding the technical problem of the system being unable to accurately determine when to enter the effective measurement area due to the random initial mold placement angle. Since the initial mold angle is uncontrollable, if the system does not have a consistent angular velocity and entry conditions, it may miss the correct trigger point or exhibit different stopping angles in different batches, causing instability in the subsequent identification angle. The solution in this embodiment can ensure the stability and consistency of the positioning process under a unified zero-point reference, ensuring that the trigger condition for entering the effective measurement area is unique, thereby improving the reproducibility and reliability of the identification starting point.

[0039] Preferably, before starting clockwise rotation, the laser displacement sensor beam is kept fixed at the edge measuring point. During clockwise rotation, H0 is continuously read at a uniform sampling rate. When H0 is less than the lower limit height for the first time, the angle of the boss rotation motor at that time is recorded as R0 and clockwise rotation continues. When H0 returns to the threshold range again, it is stopped immediately and the angle at that time is recorded as R1. R0 and R1 are used together to characterize the angle range of the mold edge height curve relative to the stop plane. The acquisition of R0 and R1 is completed in a monotonic process with the rotation angle as the independent variable.

[0040] In this embodiment, the laser displacement sensor beam is fixed at the edge measuring point before clockwise rotation begins. During clockwise rotation, H0 is continuously read at a uniform sampling rhythm. When H0 first falls below the lower limit height, the angle of the boss rotation motor at that time is recorded as R0, and clockwise rotation continues. When H0 returns to the threshold range, it stops immediately, and the angle at that time is recorded as R1. R0 and R1 are used together to characterize the angle range of the mold edge height curve relative to the stop plane. The acquisition of R0 and R1 is completed as a monotonic process with the rotation angle as the independent variable, which can solve the problems of inconsistent sampling rhythm and non-unique angle trigger events. Asynchronous rotation and sensor sampling can easily lead to missing the actual entry / exit boundary, resulting in angle jitter or repeated judgments. The solution in this embodiment, by fixing the edge measuring point and uniform sampling rhythm, achieves accurate capture of height change feature points during rotation, making the angle data of R0 and R1 unique and repeatable, thereby ensuring the reliability and accuracy of subsequent calculation of the target angle θt.

[0041] Preferably, after obtaining R0 and R1, the target angle θt is calculated, θt=(R0-R1) / 2-90°; then, the boss is rotated to the angle position corresponding to the target angle θt by a rotating motor, without changing the measuring point coordinates and Z-axis mounting posture of the laser displacement sensor during the execution process; when θt is negative, it rotates counterclockwise, and when θt is positive, it rotates clockwise, so as to unify the correspondence between the angle sign and the execution direction.

[0042] In this embodiment, after obtaining R0 and R1, the target angle θt is calculated as θt = (R0 - R1) / 2 - 90°. Then, the system rotates only to the position corresponding to the target angle θt using the boss rotary motor, without changing the coordinates of the laser displacement sensor's measuring point or the Z-axis mounting orientation during execution. When θt is negative, the rotation is counter-clockwise; when θt is positive, the rotation is clockwise. This solves the problem of inconsistency between the calculated target angle and the actual rotation direction. If the calculated angle and rotation direction do not correspond, the system may rotate to the wrong position, leading to positioning failure. This embodiment establishes a clear formula relationship and unifies symbols and directions, achieving a unique solution for the target angle and consistency in the execution path. This ensures that the system can correctly reach the target posture under different molds and batches, providing a reliable prerequisite for subsequent H1 confirmation and clamping positioning.

[0043] Preferably, the determination of H1 is triggered only after the target angle θt is reached; if H1 does not enter the threshold range, the boss rotary motor is directly instructed to rotate 90° counterclockwise based on the current angle while keeping the edge measuring point unchanged, and H1 is determined again to see if it enters the threshold range; regardless of the result of the second determination, the robot is grasped by the robot in a predetermined posture and enters the positioning step to be compatible with single anti-rotation plane and double anti-rotation plane molds.

[0044] In this embodiment, the determination of H1 is triggered only after reaching the target angle θt. If H1 does not enter the threshold range, the boss rotary motor is directly instructed to rotate 90° counterclockwise based on the current angle while keeping the edge measuring point unchanged, and H1 is determined again to see if it has entered the threshold range. Regardless of the result of the second determination, the robot arm grasps the mold in a predetermined posture and proceeds to the positioning step. This solves the problem of unreliable identification when there is symmetry ambiguity between single-plane and double-plane molds. For double-plane molds, there may be two sets of symmetrical solutions at θt. Without correction, the positioning may be incorrect. By correcting the angle by 90°, a unified identification logic under symmetrical structures is achieved, automatically adapting to single-plane and double-plane molds, thereby improving the universality and reliability of the system.

[0045] Preferably, throughout the entire identification process, the coordinates of the laser displacement sensor's measuring point remain unchanged, the Z-axis mounting posture remains unchanged, and the threshold range formed by the upper and lower limits of the height remains unchanged. Furthermore, the recording of R0 and R1, the execution of the target angle θt, and the 90° correction angle are triggered only by the angle change of the boss rotary motor. At the same time, it is stipulated that the readings of H0 and H1 are completed using the same measurement path and the same measuring point.

[0046] In this embodiment, the coordinates of the laser displacement sensor's measuring point, the Z-axis mounting posture, and the threshold range formed by the upper and lower height limits remain unchanged throughout the entire recognition process. The recording of R0 and R1, the execution of the target angle θt, and the 90° correction angle are triggered only by changes in the angle of the boss's rotary motor. Furthermore, the readings of H0 and H1 are specified to be completed using the same measurement path and the same measuring point. This solves the problem of incomparable results due to measuring point position drift, inconsistent threshold judgments, or changes in the sampling path. If the measuring point changes or different thresholds are used at different stages, inconsistencies in height judgment can easily occur, affecting angle calculation. This embodiment achieves consistency of "coordinates-angle-height" throughout the entire recognition process by unifying all constraints, ensuring that data from different stages can be directly compared, improving the repeatability and consistency across batches.

[0047] Preferably, the threshold range is preset according to the target mold specifications. The determination of H0 and H1, the stopping of the counterclockwise positioning step, and the stopping of the clockwise rotation step are all based on the threshold range as a unified scale. When H0 is within the threshold range, it means that the mold edge aligned with the laser beam is in an effective measurement posture. When H0 is less than the lower limit height, it means that the mold edge contour has entered the low position area and serves as the trigger condition for recording R0. When H0 re-enters the threshold range, it means that it has returned to an effective posture and serves as the trigger condition for recording R1.

[0048] In this embodiment, the threshold range is preset according to the target mold specifications. The determination of H0 and H1, the stopping of the counterclockwise positioning step, and the stopping of the clockwise rotation step all use the threshold range as a unified standard. When H0 is within the threshold range, it indicates that the mold edge aligned with the laser beam is in a valid measurement posture. When H0 is less than the lower limit height, it indicates that the mold edge contour has entered the low-position area and serves as the trigger condition for recording R0. When H0 re-enters the threshold range, it indicates that it has returned to a valid posture and serves as the trigger condition for recording R1. This solves the problem of inconsistent determination conditions. If different criteria are used in different steps, inconsistent results will result. The solution in this embodiment uses a unified threshold range as the basis for all determinations to achieve consistency of trigger conditions, ensuring that the acquisition logic of R0 and R1 is clear and reliable, thereby making the target angle calculation stable and controllable.

[0049] Preferably, after H1 confirmation or 90° correction is completed, the robot arm grasps the mold and places it on a base capable of positioning the mold. The main positioning cylinder is extended to make two high-precision rotatable bearings form a surface-to-line contact with the anti-rotation plane of the mold and provide the main clamping force. Then, the auxiliary positioning cylinder is extended to make two other high-precision rotatable bearings form a point-to-line contact with the arc surface of the mold and provide auxiliary clamping force. It is specified that the cylinder diameter of the main positioning cylinder is larger than that of the auxiliary positioning cylinder so that the main clamping force is greater than the auxiliary clamping force. Thus, when there is an initial angular deviation in the mold, the main positioning first achieves the correction, and then the auxiliary positioning achieves circumferential stability.

[0050] In this embodiment, after H1 confirmation or 90° correction is completed, the robotic arm grasps the mold and places it on a base capable of positioning the mold. The main positioning cylinder extends, causing two high-precision rotatable bearings to form surface-to-line contact with the mold's anti-rotation plane and provide the main clamping force. Subsequently, the auxiliary positioning cylinder extends, causing two more high-precision rotatable bearings to form point-to-line contact with the mold's arc surface and provide auxiliary clamping force. The main positioning cylinder's diameter is specified to be larger than the auxiliary positioning cylinder's diameter, ensuring the main clamping force is greater than the auxiliary clamping force. This solves the problem of indistinguishable main and auxiliary force paths and unstable positioning. This embodiment's solution, by distinguishing the forces of the main and auxiliary cylinders and combining surface-to-line and point-to-line contact modes, achieves a positioning strategy where the main reference guides the alignment, followed by stabilization by the auxiliary reference. This maintains consistency between the identification angle and the positioning angle, improving clamping accuracy and stability.

[0051] Preferably, the shafts of the two bearings used for the anti-rotation plane are parallel to the Z-axis and their outer raceways are rotatable, so that a small amount of rolling is allowed along the anti-rotation plane during the advancement of the main positioning cylinder without introducing significant frictional resistance; the shafts of the two bearings used for the arc surface are also parallel to the Z-axis and are allowed to generate adaptive rolling along the arc generatrix direction during the advancement of the secondary positioning cylinder, so as to adapt to the local roundness and cylindricity deviation of the mold cylindrical surface.

[0052] In this embodiment, the shafts of the two bearings used for the anti-rotation plane are parallel to the Z-axis, allowing their outer raceways to rotate. This allows for slight rolling along the anti-rotation plane during the main positioning cylinder's advance without introducing significant frictional resistance. Similarly, the shafts of the two bearings used for the arc surface are also parallel to the Z-axis, allowing adaptive rolling along the arc generatrix during the secondary positioning cylinder's advance. This adapts to local roundness and cylindricity deviations of the mold's cylindrical surface, solving the technical problems of high friction and easy surface damage during rigid clamping. This embodiment reduces friction during clamping through the rolling contact of rotatable bearings, preventing scratches on the mold surface while allowing adaptive compensation for roundness and cylindricity errors. This achieves reduced stress concentration and surface damage while maintaining clamping force, improving mold lifespan and tooling reliability.

[0053] Preferably, when the mold has two anti-rotation planes, the two high-precision rotatable bearings corresponding to the main positioning cylinder abut against the two anti-rotation planes respectively; when the mold has only one anti-rotation plane, the two high-precision rotatable bearings of the main positioning cylinder abut against the anti-rotation plane together, and the two high-precision rotatable bearings of the auxiliary positioning cylinder abut against the arc surface to provide reaction force.

[0054] In this embodiment, when the mold has two anti-rotation planes, the two high-precision rotatable bearings corresponding to the main positioning cylinder abut against the two anti-rotation planes respectively; when the mold has only one anti-rotation plane, the two high-precision rotatable bearings of the main positioning cylinder abut against the anti-rotation plane together, and the two high-precision rotatable bearings of the auxiliary positioning cylinder abut against the arc surface to provide reaction force, which can solve the problem of incompatibility between single-plane molds and double-plane molds. In traditional designs, tooling is often designed for a single type of mold and lacks universality. The solution in this embodiment defines two clamping strategies under the same positioning structure to achieve compatibility with different mold structures, so that the production line can adapt to different mold types without changing the fixtures, thereby improving the flexibility and versatility of the automated production line.

[0055] Preferably, the angle zeroing operation is performed only after the robot arm first places the mold at the center of the boss and completes the concentricity of the axis. Subsequently, all angle events are recorded under the same zero point reference, including the stopping angle when counterclockwise positioning enters the threshold range, R0 when H0 is less than the lower limit height during clockwise rotation, R1 when H0 returns to the threshold range during clockwise rotation, and the execution of the target angle θt and the 90° correction angle. If the robot arm is removed and repositioned midway, it must be zeroed again and executed again.

[0056] In this embodiment, the angle zeroing operation is performed only after the robot arm first places the mold at the center of the boss and completes the concentricity of the axis. Subsequently, all angle events are recorded under the same zero-point reference, including the stopping angle when counterclockwise positioning enters the threshold range, R0 when H0 is less than the lower limit height during clockwise rotation, R1 when H0 returns to the threshold range during clockwise rotation, and the execution of the target angle θt and the 90° correction angle. Any removal and repositioning during the process requires re-zeroing and re-execution, which solves the problem of untraceable identification data caused by angle reference drift. If the workpiece is removed midway or the reference is inconsistent, angle determination will be chaotic. This embodiment's solution, by clearly defining the timing of angle zero-point establishment and reset requirements, ensures that all angle events are based on a unified reference, thereby ensuring the consistency and traceability of the angle data chain and improving data reliability across batches and workstations.

[0057] It should be noted that the molding machine refers to a glass aspherical lens forming machine, which is a machine that uses high temperature and pressure to form softened glass into high-precision aspherical lenses in a single operation under oxygen-free conditions. An automatic loader automatically removes the lenses from the mold after molding in the molding machine, places them in a predetermined position, then places the pre-formed parts into the mold, and finally transports the mold back to the molding machine. Generally, the mold shapes are cylindrical and cubic, and a mold consists of 1, 2, 3, 4, 5, 6, 8, 9, or 10 cavities, meaning that multiple lenses can be pressed in a single operation by combining molds. In the ultra-precision machining process, cylindrical molds are designed with one or two anti-rotation planes to prevent rotation or displacement within the fixture. To enable the automatic loader to fix the mold's position and accurately remove the lenses from the mold, the above embodiments propose a method for automatically identifying the anti-rotation planes of the mold. For example, the method for automatically identifying the anti-rotation plane of a mold may specifically include the following implementation details No. 1-No. 9: 1. After the mold (cylinder) comes out of the molding machine, the angle of the mold is random. 2. The robot grips the mold and places it at the center of a rotatable boss, and the current angle of the boss rotation motor is zeroed. 3. A laser displacement sensor is installed on the Z-axis. 4. The X and Y axes are moved to move the laser displacement sensor beam to the edge of the mold, with the X-axis coordinate = mold center and the Y-axis coordinate = mold center + mold radius - 1mm. 5. The laser displacement sensor starts reading the mold height H0. If H0 is within the set upper and lower limits of the mold height, No. 6 is executed; otherwise, No. 6-1 is executed. 6-1. The boss rotation motor starts rotating counterclockwise. When H0 is within the set upper and lower limits of the mold height, the boss rotation motor immediately stops. Execute Step No. 6. 6. The boss rotary motor starts rotating clockwise. When H0 is less than the set lower limit height of the mold, record the current angle R0 of the rotating boss motor. When H0 is within the set upper and lower limit heights of the mold, the boss rotary motor immediately stops, and record the current angle R1 of the rotating boss motor. 7. Execute the boss rotary motor to rotate, with a rotation angle of (R0 - R1) / 2 - 90°. 8. The laser displacement sensor starts reading the mold height H1. When H1 is within the set upper and lower limit heights of the mold, execute Step No. 9. Otherwise, the boss rotating motor rotates 90° counterclockwise before executing No. 9. 9. The robot arm picks up the mold and places it on a base that can position the mold. The main positioning cylinder extends, and two high-precision rotatable bearings support the anti-rotation plane of the mold. Then, the auxiliary positioning cylinder extends, and two high-precision rotatable bearings support the arc surface of the mold. The cylinder diameter of the main positioning cylinder is larger than that of the auxiliary positioning cylinder, so even if the mold has a certain angular deviation before positioning, it can automatically guide the mold to the correct position.

[0058] See below, 3- Figure 6The following is an example of a rapid mirror removal process (counterclockwise) using a six-cavity cylindrical mold to illustrate some specific embodiments of the present invention.

[0059] First, the laser displacement sensor is fixed in the Z-axis direction of the rotating cylindrical mold, with the laser beam pointing vertically downwards.

[0060] Secondly, by rotating the cylindrical mold counterclockwise at a fixed angular velocity, the beam measuring point may fall onto the surface of the cylindrical mold, or it may not fall onto the surface of the cylindrical mold due to the anti-rotation plane set on the cylindrical mold. This allows for continuous reading of the mold height H0. For example... Figure 3 The measuring points sometimes fall on the surface of the cylindrical mold, and sometimes outside the surface. See 3- Figure 6 In the process, some measuring points represent a single point, while others represent multiple points, such as two (see...). Figure 5 ).because Figure 3 The relationship between the measuring point and the surface of the cylindrical mold has already been demonstrated. Figures 4-6 The measurement points in this example will not be described in text on the diagram one by one.

[0061] Then, by reading the mold height H0, the anti-rotation plane of the cylindrical mold is identified to fix the position of the mold. A mechanical coordinate system is established, and the center of the mold circle fixed on the tooling is taken as the origin of the mold coordinate system. The offset of the mold center in the mechanical coordinate system is obtained by the three-point circle determination method as the center offset. The number of mold cavities N, the radius of the mold core ring R, and the deflection angle θ1 of the first cavity are set, and the mirror selection order of the cavity number is set to counterclockwise or clockwise. When the cavity number is selected to be counterclockwise, the two-dimensional coordinates in the mold coordinate system are calculated for the k-th cavity. Xk = R × cos[θ1 + (k - 1) / N × 360°], Yk = R × sin[θ1 + (k - 1) / N × 360°]; When the selected cavity number is clockwise, calculate the two-dimensional coordinates in the mold coordinate system for the kth cavity: Xk = R × cos[θ1 - (k - 1) / N × 360°], Yk = R × sin[θ1 - (k - 1) / N × 360°]; Perform homogeneous translation of (Xk, Yk) with the center offset to obtain the target grasping point (Xk′, Yk′) in the mechanical coordinate system.

[0062] Finally, the lens-retrieving robot is controlled to move to the target grasping point (Xk′, Yk′) to grasp the lens mold cavity. The value of k is 1 to N to complete the removal of the lens cavity by cavity in the clockwise or counterclockwise lens-retrieving sequence of the entire optical lens production mold.

[0063] It should be noted that the above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention, and the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A lens retrieval method based on a general algorithm for lens mold cavity coordinates, characterized in that, include: Automatically identify the anti-rotation plane of the optical lens production mold to fix the position of the mold, establish a mechanical coordinate system and take the center of the mold fixed on the tooling as the origin of the mold coordinate system; The offset of the mold center in the mechanical coordinate system is obtained by the three-point circle determination method and used as the center offset. The number of mold cavities N, the radius of the mold core ring R and the first cavity deflection angle θ1 are set, and the mirror taking order of the cavity number is set to counterclockwise or clockwise. When selecting the acupoint number counterclockwise, calculate the two-dimensional coordinates in the mold coordinate system for the kth acupoint: Xk=R×cos〔θ1+(k-1) / N×360°〕,Yk=R×sin〔θ1+(k-1) / N×360°〕; When selecting the acupoint number clockwise, calculate the two-dimensional coordinates in the mold coordinate system for the k-th acupoint: Xk=R×cos〔θ1-(k-1) / N×360°〕,Yk=R×sin〔θ1-(k-1) / N×360°〕; perform homogeneous translation of (Xk,Yk) with the center offset to obtain the target grasping point (Xk′,Yk′) in the mechanical coordinate system; The lens-retrieving robot arm is controlled to move to the target grasping point (Xk′, Yk′) to grasp the lens mold cavity. The value of k is 1 to N in a cycle to complete the removal of the lens cavity one by one in the clockwise or counterclockwise lens-retrieving sequence of the entire optical lens production mold. When automatically identifying the anti-rotation plane of an optical lens manufacturing mold, the following is included: For a cylindrical mold with one or two anti-rotation planes, a robot arm removes the mold from the molding machine and places it at the center of a rotatable boss, and sets the current angle of the boss's rotation motor to zero; a laser displacement sensor is installed above the boss along the Z-axis, and an X, Y, Z rectangular coordinate system is established with the center of the boss as the origin, and the Z-axis is made coaxial with the rotation axis of the boss. Move the X and Y axes so that the laser displacement sensor beam is located at the edge of the mold and meets the edge measurement point. The edge measurement point is the X coordinate of the mold center in the X direction and the Y coordinate of the mold center in the Y direction plus the mold radius minus a preset distance. The preset distance is the radial inward shrinkage of the mold. Start the laser displacement sensor to collect the mold edge height H0. When H0 is within the threshold range, enter the clockwise rotation step; otherwise, enter the counterclockwise positioning step. The threshold range is the range between the upper limit height and the lower limit height of the mold. In the counterclockwise positioning step, the boss rotary motor is driven to rotate counterclockwise until H0 enters the threshold range and stops immediately. Then, the clockwise rotation step is performed. In the clockwise rotation step, the boss rotary motor is driven to rotate clockwise. When H0 is detected to be less than the lower limit height, the current angle is recorded as R0. When H0 is detected to enter the threshold range again, the current angle is stopped immediately and recorded as R1. Then, the boss rotary motor is driven to rotate by a target angle θt equal to (R0-R1) / 2-90°. At the target angle θt, a laser displacement sensor collects the mold edge height H1. When H1 is within the threshold range, a robot transfers the mold to a positionable base. The main positioning cylinder extends to make two high-precision rotatable bearings abut against the mold's anti-rotation plane, and the auxiliary positioning cylinder extends to make two other high-precision rotatable bearings abut against the mold's arc surface. The diameter of the main positioning cylinder is larger than that of the auxiliary positioning cylinder. When H1 is not within the threshold range, the boss rotary motor is first rotated counterclockwise by 90° to correct the angle before the transfer and positioning steps are performed.

2. The method according to claim 1, characterized in that, When fixing the position of the mold, it is positioned by a combination of the main positioning cylinder and the auxiliary positioning cylinder; the number of mold cavities N=6, the radius of the mold core ring R=15, and the deflection angle of the first cavity θ1=240°.

3. The method according to claim 1, characterized in that, With the angle of the boss rotary motor zeroed, the boss is continuously rotated counterclockwise at a fixed angular velocity, and H0 is read in real time. H0 is compared with the set upper and lower limits of the mold height. If H0 enters the threshold range for the first time, the counterclockwise rotation is stopped immediately and the clockwise rotation step is started. If H0 crosses the threshold range and leaves again during the counterclockwise rotation, the counterclockwise rotation continues until it enters the threshold range again and stops immediately to avoid misjudgment caused by the random initial angle of the mold. The angular velocity remains constant throughout the positioning process to ensure the consistency of the angle criterion and the height criterion.

4. The method according to claim 1, characterized in that, Before starting clockwise rotation, the laser displacement sensor beam is kept fixed at the edge measuring point. During the clockwise rotation, H0 is continuously read at a uniform sampling rate. When H0 is less than the lower limit height for the first time, the angle of the boss rotation motor at that time is recorded as R0 and the clockwise rotation continues. When H0 returns to the threshold range again, it is stopped immediately and the angle at that time is recorded as R1. R0 and R1 are used together to characterize the angle range of the mold edge height curve relative to the stop plane. The acquisition of R0 and R1 is completed in a monotonic process with the rotation angle as the independent variable.

5. The method according to claim 1, characterized in that, After obtaining R0 and R1, the target angle θt is calculated as θt = (R0 - R1) / 2 - 90°. Then, the platform is rotated to the angular position corresponding to the target angle θt by a rotary motor. During the execution, the coordinates of the measuring point of the laser displacement sensor and the installation posture of the Z-axis are not changed. When θt is negative, the rotation is counterclockwise, and when θt is positive, the rotation is clockwise to unify the correspondence between the angle sign and the execution direction.

6. The method according to claim 1, characterized in that, The determination of H1 is triggered only after the target angle θt is reached; if H1 does not enter the threshold range, the boss rotary motor is directly instructed to rotate 90° counterclockwise based on the current angle while keeping the edge measuring point unchanged, and H1 is determined again to see if it enters the threshold range; regardless of the result of the second determination, the robot is grasped by the robot in a predetermined posture and enters the positioning step to be compatible with single anti-rotation plane and double anti-rotation plane molds.

7. The method according to claim 1, characterized in that, Throughout the entire recognition process, the coordinates of the laser displacement sensor's measuring point remain unchanged, the Z-axis mounting posture remains unchanged, and the threshold range formed by the upper and lower limits of the height remains unchanged. The recording of R0 and R1, the execution of the target angle θt, and the 90° correction angle are triggered only by the angle change of the boss rotary motor. At the same time, it is stipulated that the readings of H0 and H1 are completed using the same measurement path and the same measuring point.

8. The method according to claim 1, characterized in that, The threshold range is preset according to the target mold specifications. The determination of H0 and H1, the stopping of the counterclockwise positioning step, and the stopping of the clockwise rotation step are all based on the threshold range as a unified scale. When H0 is within the threshold range, it means that the mold edge aligned with the laser beam is in an effective measurement posture. When H0 is less than the lower limit height, it means that the mold edge contour has entered the low position area and serves as the trigger condition for recording R0. When H0 re-enters the threshold range, it means that it has returned to an effective posture and serves as the trigger condition for recording R1.

9. A lens retrieval system based on a general algorithm for lens mold cavity coordinates, characterized in that, The lens retrieval system based on the general algorithm for lens mold coordinates uses the lens retrieval method based on the general algorithm for lens mold coordinates as described in any one of claims 1-8 to grasp the lens in the lens mold cavity.

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