Double-drive gantry beam deviation detection and correction method, electronic equipment and storage medium

Abstract

The application provides a double-drive gantry machine tool beam deviation detection and correction method, electronic equipment and a storage medium. The gantry machine tool comprises a main shaft and a slave shaft, the main shaft and the slave shaft are respectively configured with an origin switch, the main shaft and the slave shaft are respectively driven by corresponding servo motors, each servo motor is configured with a corresponding encoder, the double-drive gantry machine tool beam deviation detection method comprises two parts of static detection and dynamic detection, the static detection process is used for judging whether the gantry beam exists initial skew condition at start-up, and the dynamic detection process is used for judging whether the gantry beam appears skew condition at work. The combination of static detection and dynamic detection realizes gantry beam deviation protection in the whole period, and can effectively improve the precision and stability of machine tool machining.

Description

Technical Field

[0001] This invention belongs to the field of gantry machine tool technology, specifically relating to a method for detecting and correcting deviations of a dual-drive gantry beam, electronic equipment, and storage medium. Background Technology

[0002] Dual-drive gantry milling machines are widely used in high-precision machining industries (such as aerospace and large mold manufacturing), but their crossbeam deviation problems (such as synchronization errors and torsional deformation) directly affect machining accuracy. Currently, detection and calibration technologies have made some progress, but many technical bottlenecks and engineering challenges remain.

[0003] Regarding beam deviation detection: Using a laser interferometer to measure the synchronous error of two axes has the advantages of high accuracy (µm level); however, it is susceptible to environmental factors (temperature, vibration), has complex operation, and is relatively expensive.

[0004] Using a ballbar analyzer to analyze the synchronicity of the two axes through circular trajectory has the advantage of rapid detection; however, it can only reflect dynamic roundness error and cannot directly measure beam torsion.

[0005] Sampling electronic levels and tilt sensors are used to detect the static levelness and dynamic tilt of crossbeams. The advantage is that they are easy to deploy; the disadvantages are that the dynamic response is slow and the accuracy is low.

[0006] Using machine vision, the calibration plate is photographed by an industrial camera to calculate the crossbeam offset. The advantages are that it is non-contact and adaptable to complex environments; the disadvantages are that it is sensitive to light, the calibration is complex, and the image becomes blurry when moving at high speed.

[0007] The method employs multi-sensor fusion, which combines data from grating rulers, inclinometers, strain gauges, and other sources to comprehensively assess beam deformation. Its advantages include data complementarity and improved reliability; however, its disadvantages include system complexity, high requirements for data fusion algorithms, and high cost.

[0008] Regarding beam alignment: Mechanical adjustment is used to adjust the guide rail preload and gear backlash elimination mechanism. The advantage is that it directly solves hardware problems and is effective in the long term; the disadvantage is that it relies on manual experience and the adjustment is time-consuming.

[0009] CNC compensation is used to optimize motion accuracy through pitch compensation, backlash compensation, and dual-axis synchronous gain adjustment. The advantage is that no hardware modification is required and it takes effect quickly; the disadvantage is that it can only compensate for systematic errors and cannot cope with dynamic deformation.

[0010] Existing technologies for detecting crossbeam deviation in dual-drive gantry milling machines rely on adding expensive hardware testing equipment, which is complex to operate and costly. Crossbeam correction technology relies on manual experience and is time-consuming. CNC compensation can only compensate for minor systematic errors and cannot cope with dynamic deformation of the crossbeam, thus failing to fundamentally solve the problem of crossbeam skew. Summary of the Invention

[0011] In view of the above-mentioned problems in the prior art, the purpose of this invention is to provide a method for detecting and correcting crossbeam deviation of a dual-drive gantry milling machine, which includes two parts: static detection and dynamic detection. The static detection process is used to determine whether there is an initial skewness of the gantry crossbeam when the machine is started, and the dynamic detection process is used to determine whether the gantry crossbeam is skewed during operation. The combination of static detection and dynamic detection realizes full-time protection against gantry crossbeam deviation, which can effectively improve the accuracy and stability of machine tool processing.

[0012] A method for detecting and correcting the deviation of the crossbeam of a dual-drive gantry milling machine, wherein the gantry milling machine includes a spindle and a driven spindle, the spindle and the driven spindle are respectively equipped with origin switches, the spindle and the driven spindle are respectively driven by corresponding servo motors, and each servo motor is equipped with a corresponding encoder; The method for detecting crossbeam deviation in a dual-drive gantry milling machine includes the following steps: Set the reference value for when the gantry beam is aligned and the tolerance threshold for gantry beam tilt; By performing two spindle homing operations using the slave axis origin switch and slave axis encoder, and the spindle origin switch and spindle encoder respectively, the position difference between the spindle motors during the two spindle homing operations is calculated. Determine if there is initial skewness in the gantry beam: If the difference between the position of the motor and the reference value when the spindle returns to the origin twice exceeds the gantry beam skewness tolerance threshold, then the gantry beam is determined to have initial skewness; otherwise, the gantry beam is determined not to have initial skewness, and the machine tool will operate normally. After the machine tool is working normally, record the initial position difference between the spindle motor and the driven motor, and continuously monitor the position difference between the spindle motor and the driven motor during the machining process; To determine whether the gantry beam is skewed during machining: If the difference between the initial position difference between the spindle motor and the driven spindle motor and the position difference between the spindle motor and the driven spindle motor during machining exceeds the gantry beam skew tolerance threshold, then the gantry beam is determined to be skewed; otherwise, the gantry beam is determined not to be skewed and the machine tool is operating normally.

[0013] Preferably, the reference value for when the gantry beam is aligned is a fixed value obtained after machine tool debugging. The process for determining the reference value for when the gantry beam is aligned is as follows: When the gantry beam is in the upright position, the difference between the feedback value of the spindle motor after the spindle performs the return-to-origin operation through the origin switch of the slave axis and the Z-phase signal, and the feedback value of the spindle motor after the spindle performs the return-to-origin operation through the origin switch of the spindle and the Z-phase signal.

[0014] Preferably, the gantry beam skew tolerance threshold represents the acceptable degree of gantry beam skew. When the degree of gantry beam skew exceeds the gantry beam skew tolerance threshold, the machine tool triggers corresponding alarm and self-protection operations.

[0015] Preferably, the spindle homing operation is performed twice by using the slave axis origin switch and slave axis encoder, and the spindle origin switch and spindle encoder respectively, and the position difference between the spindle motors during the two spindle homing operations is calculated. The specific process is as follows: The spindle returns to the origin for the first time by using the origin switch of the slave axis and the Z-phase signal, and records the motor feedback value when the spindle moves to the position corresponding to the origin switch of the slave axis. By using the spindle origin switch and Z-phase signal, the spindle return to origin operation is executed again, and the motor feedback value at the position corresponding to the spindle origin switch is recorded. Calculate the position difference between the spindle servo motors during the two spindle return-to-origin operations.

[0016] Another objective of this invention is to provide a method for correcting the crossbeam deviation of a dual-drive gantry milling machine, applicable after determining that the gantry crossbeam is skewed according to the aforementioned method for detecting crossbeam deviation in a dual-drive gantry milling machine. The method specifically includes the following steps: When the gantry beam has an initial skew, the displacement that the slave axis needs to move at this time is the difference between the position difference between the motors when the main shaft returns to the origin twice and the reference value. When the gantry beam becomes skewed during processing, the gantry machine tool is returned to its origin. The spindle origin switch and encoder are used to perform two spindle return-to-origin operations, and the position difference between the spindle motors during the two spindle return-to-origin operations is calculated. The displacement that the slave axis needs to move at this time is the difference between the position difference between the motors during the two spindle return-to-origin operations and the reference value.

[0017] Preferably, after determining the displacement that the slave axis needs to move, the master axis and the slave axis are decoupled so that the slave axis can move independently. The slave axis is driven to move the corresponding displacement so that the gantry beam returns to the center. After the slave axis completes the movement, the master axis and the slave axis are coupled together to restore the normal state.

[0018] A third objective of this invention is to provide an electronic device comprising: a memory and at least one processor, wherein the memory stores a computer program; and the at least one processor invokes the computer program in the memory to cause the electronic device to execute the above-described method for correcting the crossbeam deviation of a dual-drive gantry milling machine.

[0019] A fourth objective of the present invention is to provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for correcting the crossbeam deviation of a dual-drive gantry milling machine.

[0020] The beneficial effects of this invention are: This invention sets origin switches on the main shaft and the slave shaft respectively, and combines them with the Z-phase signal of the encoder of the servo motor to achieve accurate comparison of two return-to-origin operations of the main shaft. It can obtain high-precision detection results without relying on expensive hardware such as laser interferometers and grating rulers, thereby significantly reducing system costs and improving detection reliability.

[0021] By setting up both static and dynamic detection processes, it is possible to determine whether there is an initial skewness of the crossbeam when the machine tool is turned on, so as to prevent the machine tool from entering the machining process with deviation. At the same time, it is possible to detect whether the crossbeam is skewed in real time during the machining process, forming a full-time deviation monitoring system, which ensures the stability and safety of the entire machining process.

[0022] This invention, upon detecting beam misalignment, automatically calculates the required displacement compensation, decouples the master and slave shafts, and drives the slave shaft to move independently to achieve correction, thereby quickly restoring the beam to its upright position. Compared to traditional methods relying on manual adjustment, this invention offers advantages such as high automation, high correction efficiency, and controllable precision, effectively reducing reliance on manual experience and maintenance time. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the mechanical structure of the gantry milling machine involved in the present invention; Figure 2 This is a schematic diagram of the structure of the gantry beam when it is aligned. Figure 3 This is a schematic diagram of the structure of the gantry beam when it is tilted according to the present invention; Figure 4 This is a flowchart of the gantry milling machine initialization and debugging method of the present invention; Figure 5 This is a flowchart of the method for obtaining the position of the spindle motor twice according to the present invention; Figure 6 This is a flowchart of the method for determining whether the gantry beam is skewed according to the present invention; Figure 7 This is a flowchart of the method for correcting the gantry beam of the present invention. Detailed Implementation

[0024] Example 1 like Figure 1 As shown, a method for detecting crossbeam deviation in a dual-drive gantry milling machine includes two parts: static detection and dynamic detection. The static detection process is used to determine whether there is an initial skewness in the gantry crossbeam when the machine is started, and the dynamic detection process is used to determine whether the gantry crossbeam is skewed during operation. The combination of static and dynamic detection achieves full-time protection against gantry crossbeam deviation, which can effectively improve the accuracy and stability of machine tool processing.

[0025] like Figures 1 to 3 As shown, the dual-drive gantry milling machine includes a spindle and a driven spindle, each equipped with a corresponding origin switch. The origin switch is a position reference detection device used to define the reference point position of the drive axis. That is, through control signals, the corresponding drive axis can be moved to the corresponding reference point position, achieving a repeatable positioning function. It is important to note that the two origin switches should be installed in staggered positions (a stagger distance of at least 30cm is recommended) to improve detection accuracy.

[0026] The main spindle and driven axis are each driven by a servo motor. In each servo cycle, the gantry milling machine's main spindle plans its displacement increment, and the driven axis follows the same displacement increment, achieving synchronous movement between the main and driven axes. Furthermore, each drive motor is equipped with a corresponding encoder, which accurately calculates the number of rotations of the drive motor using the encoder's Z-phase signal, thereby improving detection accuracy.

[0027] like Figures 4 to 6 As shown, the method for detecting crossbeam deviation in a dual-drive gantry milling machine includes the following steps: Step 1: Set the baseline reference value when the gantry beam is aligned, and mark it as init. At the same time, set the gantry beam skew tolerance threshold, and mark it as diff_max.

[0028] The reference value init is obtained based on precise debugging. It represents the feedback value of the spindle motor after the spindle performs a return-to-origin operation through the origin switch of the slave axis and the optional Z-phase signal when the gantry beam is in the upright state. The difference between the feedback value of the spindle motor and the feedback value of the spindle motor after the spindle performs a return-to-origin operation through the origin switch of the spindle and the optional Z-phase signal is a fixed value init.

[0029] The gantry beam skew tolerance threshold, diff_max, represents the acceptable degree of gantry beam skewness. When the skewness of the gantry beam exceeds this tolerance threshold, diff_max, the machine tool will trigger corresponding alarm and self-protection operations.

[0030] Furthermore, the origin switch itself has the following drawbacks: (1) The trigger position may have a mechanical error of several micrometers to tens of micrometers; (2) Due to the influence of environment and installation location, the repeatability is not high.

[0031] By using the origin switch in conjunction with the motor's Z-phase signal, when the machine tool moves and triggers the origin switch, the system does not immediately latch. Instead, it continues to search for the nearest Z-phase pulse and uses that point as the true zero point. Furthermore, since the Z-phase signal is directly generated by the encoder and has very high precision, it can obtain accurate motor position, reducing the cumulative error of subsequent calculations and thus improving the accuracy of beam skew detection.

[0032] Step 2: Perform the spindle return-to-origin operation for the first time by using the origin switch of the slave axis and the optional Z-phase signal, and record the motor feedback value when the spindle moves to the position corresponding to the origin switch of the slave axis, and mark it as master.motor_pos_fb_1.

[0033] Step 3: Using the spindle origin switch and the optional Z-phase signal, perform the spindle return-to-origin operation again, and record the motor feedback value when the spindle moves to the position corresponding to the spindle origin switch, marked as: master.motor_pos_fb_2.

[0034] Step 4: Calculate the position difference between the spindle servo motors during the two spindle return-to-origin operations, and mark it as: diff=master.motor_pos_fb_1-master.motor_pos_fb_2.

[0035] Step 5: Determine whether the gantry beam has an initial tilt based on the position difference value (diff) calculated in Step 4. The absolute value of the difference between the motor position difference (diff) when the spindle returns to the origin twice and the reference value (init) is compared with the gantry deviation threshold (diff_max). That is, it is determined whether abs(diff-init) > diff_max. When the absolute value of the difference between the position difference value diff and the reference value init exceeds the gantry deviation threshold diff_max, it is determined that the gantry beam is initially skewed. At this time, the machine tool system is triggered to give a deviation alarm prompt through the human-machine interface and prohibit the machine tool from continuing to work.

[0036] When the absolute value of the difference between the position difference value *diff* and the reference value *init* does not exceed the gantry deviation threshold *diff_max*, it is determined that the gantry beam is initially not skewed. At this time, the machine tool operates normally, and the initial position difference between the spindle motor and the slave motor is recorded as: *beg_diff = master.motor_pos_fb - slave.motor_pos_fb*. Here, *master.motor_pos_fb* represents the position of the gantry spindle motor, and *slave.motor_pos_fb* represents the position of the gantry slave motor.

[0037] Step 6: After the machine tool is working normally, during each servo cycle of the machining process, continuously detect the position difference between the spindle motor and the slave motor during the machining process, and mark it as: run_diff=master.motor_pos_fb-slave.motor_pos_fb.

[0038] Step 7: Determine if the gantry beam is skewed during machine tool processing. The initial position difference between the spindle motor and the driven motor, beg_diff, is compared with the absolute value of the difference between the position difference between the spindle motor and the driven motor during the machining process, and the gantry deviation threshold, diff_max. That is, it is determined whether abs(run_diff-beg_diff) > diff_max. When the absolute value of the difference between the initial position difference beg_diff and the position difference run_diff during the machining process exceeds the gantry deviation threshold diff_max, it is determined that the gantry beam is skewed during the machining process. At this time, the machine tool system is triggered to give a deviation alarm prompt through the human-machine interface and prohibit the machine tool from continuing to work.

[0039] If the absolute value of the difference between the initial position difference beg_diff and the position difference run_diff during the machining process does not exceed the gantry deviation threshold diff_max, then the position difference between the master spindle motor and the slave spindle motor during the machining process will continue to be recorded and marked as: run_diff=master.motor_pos_fb-slave.motor_pos_fb.

[0040] During the machine tool processing, the tilt of the gantry beam is continuously monitored until the machine tool stops working.

[0041] Example 2 In the process of detecting the crossbeam deviation of the dual-drive gantry milling machine described in Example 1, after the machine tool system issues an alarm message, the position of the gantry crossbeam needs to be corrected.

[0042] like Figure 7As shown, the method for correcting the crossbeam deviation of the dual-drive gantry milling machine includes the following steps: When the gantry beam has an initial skew, that is, the gantry beam is initially skewed as determined by step five in Example 1, the gantry beam skew amount delta=diff-init is obtained, which is the displacement that needs to be moved from the axis.

[0043] When the gantry beam becomes skewed during processing, i.e., the skewness of the gantry beam during processing is determined by step seven in Example 1, then steps two to five in Example 1 need to be executed to obtain the difference between the position difference diff between the motors when the spindle returns to the origin twice and the difference between the reference value init. The skewness delta = diff - init can then be obtained, which is the displacement that the shaft needs to move.

[0044] After obtaining the required displacement of the slave axis, decouple the master and slave axes, allowing the slave axis to move independently. Drive the slave axis to move the corresponding displacement, causing the gantry beam to return to its upright position. It is important to note that the slave axis's moving speed must not exceed the master axis's home latching speed (ideally no higher than 10 m / s). Once the slave axis has completed its movement, the master and slave axes can be coupled back to normal operation.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting crossbeam deviation in a dual-drive gantry milling machine, characterized in that, The gantry milling machine includes a main spindle and a slave spindle. The main spindle and the slave spindle are each equipped with an origin switch. The main spindle and the slave spindle are each driven by a corresponding servo motor. Each servo motor is equipped with a corresponding encoder. The method for detecting crossbeam deviation in a dual-drive gantry milling machine includes the following steps: Set the reference value for when the gantry beam is aligned and the tolerance threshold for gantry beam tilt; By performing two spindle homing operations using the slave axis origin switch and slave axis encoder, and the spindle origin switch and spindle encoder respectively, the position difference between the spindle motors during the two spindle homing operations is calculated. Determine if there is initial skewness in the gantry beam: If the difference between the position of the motor and the reference value when the spindle returns to the origin twice exceeds the skewness tolerance threshold of the gantry beam, then it is determined that there is initial skewness in the gantry beam. Otherwise, it is determined that the gantry beam does not have an initial tilt, and the machine tool is operating normally; After the machine tool is working normally, record the initial position difference between the spindle motor and the driven motor, and continuously monitor the position difference between the spindle motor and the driven motor during the machining process; To determine whether the gantry beam is skewed during machining: If the difference between the initial position difference between the spindle motor and the driven motor and the position difference between the spindle motor and the driven motor during machining exceeds the gantry beam skew tolerance threshold, then the gantry beam is determined to be skewed; otherwise, the gantry beam is determined not to be skewed and the machine tool is working normally. The reference value for when the gantry beam is aligned is a fixed value obtained after machine tool debugging. The process for determining the reference value for when the gantry beam is aligned is as follows: When the gantry beam is in the upright position, the difference between the feedback value of the spindle motor after the spindle performs the return-to-origin operation through the origin switch of the slave axis and the Z-phase signal, and the feedback value of the spindle motor after the spindle performs the return-to-origin operation through the origin switch of the spindle and the Z-phase signal. The process involves performing two spindle homing operations using the slave axis origin switch and slave axis encoder, and the spindle origin switch and spindle encoder, respectively, and calculating the position difference between the spindle motors during the two homing operations. The specific process is as follows: The spindle returns to the origin for the first time by using the origin switch of the slave axis and the Z-phase signal, and records the motor feedback value when the spindle moves to the position corresponding to the origin switch of the slave axis. By using the spindle origin switch and Z-phase signal, the spindle return to origin operation is executed again, and the motor feedback value at the position corresponding to the spindle origin switch is recorded. Calculate the position difference between the spindle servo motors during the two spindle return-to-origin operations.

2. The method for detecting crossbeam deviation of a dual-drive gantry milling machine according to claim 1, characterized in that, The gantry beam skew tolerance threshold indicates the acceptable degree of gantry beam skew. When the degree of gantry beam skew exceeds the gantry beam skew tolerance threshold, the machine tool will trigger corresponding alarm and self-protection operations.

3. A method for correcting the crossbeam deviation of a dual-drive gantry milling machine, characterized in that, The method applicable to dual-drive gantry milling machine tool crossbeam deviation detection method as described in any one of claims 1 to 2, after determining that the gantry crossbeam is skewed, specifically includes the following steps: When the gantry beam has an initial skew, the displacement that the slave axis needs to move at this time is the difference between the position difference between the motors when the main shaft returns to the origin twice and the reference value. When the gantry beam becomes skewed during processing, the gantry machine tool is returned to its origin. The spindle origin switch and encoder are used to perform two spindle return-to-origin operations, and the position difference between the spindle motors during the two spindle return-to-origin operations is calculated. The displacement that the slave axis needs to move at this time is the difference between the position difference between the motors during the two spindle return-to-origin operations and the reference value.

4. The method for correcting the crossbeam deviation of a dual-drive gantry milling machine according to claim 3, characterized in that, After determining the required displacement of the slave axis, decouple the master axis and slave axis so that the slave axis can move independently. Drive the slave axis to move the corresponding displacement so that the gantry beam returns to the center. After the slave axis completes the movement, couple the master axis and slave axis back to normal.

5. An electronic device, characterized in that, The electronic device includes: a memory and at least one processor, wherein the memory stores a computer program; the at least one processor invokes the computer program in the memory to cause the electronic device to perform the crossbeam deviation correction method for a dual-drive gantry milling machine as described in claim 4.

6. A computer-readable storage medium storing a computer program thereon, characterized in that, When the computer program is executed by the processor, it implements the method for correcting the crossbeam deviation of a dual-drive gantry milling machine as described in claim 4.

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