Automatic calibration control method and system of machine tool measuring head

Abstract

The invention discloses an automatic calibration control method and system for a machine tool measuring head, and relates to the technical field of machine tools, and the method comprises the steps: carrying out the monitoring and judgment through a calibration triggering condition, and carrying out the initialization configuration of calibration hardware when the triggering condition is met; planning a touch measurement path according to the diameter of the standard ball and the measurement range of the measuring head; based on the touch path, controlling a measuring head to contact a standard spherical surface at a preset speed through a machine tool and recording coordinates of a contact point; according to the recorded coordinate data of the contact point, performing fitting calculation on the coordinates of the center of sphere and the radius of the standard sphere; and calculating a measuring head radius compensation value according to a difference value between the fitting standard ball radius and the actual radius, and performing calibration control on the machine tool measuring head by using the measuring head radius compensation value. Therefore, the technical effects of improving the calibration precision and the calibration efficiency and enhancing the environmental adaptability of calibration are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of machine tools, and in particular to an automatic calibration control method and system for a machine tool probe. Background Art

[0002] Traditional machine tool probe calibration methods usually rely on manual operation and simple measurement processes. However, as the manufacturing industry's requirements for processing accuracy continue to increase, the limitations of traditional calibration methods are gradually becoming apparent.

[0003] Existing calibration methods often require manual intervention, making the process complex and inefficient. Most use a fixed touch probe path, making it difficult to flexibly adjust based on probe characteristics and standard ball size, resulting in large calibration errors. Furthermore, existing technologies fail to adequately consider the impact of environmental factors (such as temperature changes) on calibration results, resulting in reduced calibration accuracy. Finally, existing calibration methods lack real-time monitoring capabilities, making it impossible to promptly detect deviations in the probe's calibration status, which impacts machining quality. Summary of the Invention

[0004] The present invention provides an automatic calibration control method and system for a machine tool probe to solve the technical problems of insufficient calibration accuracy, low calibration efficiency, and poor environmental adaptability in the prior art, thereby achieving the technical effects of improving calibration accuracy and calibration efficiency and enhancing the environmental adaptability of calibration.

[0005] In a first aspect, the present invention provides an automatic calibration control method for a machine tool probe, wherein the automatic calibration control method for a machine tool probe comprises:

[0006] Calibration trigger conditions are used for monitoring and judgment, and when the trigger conditions are met, the calibration hardware is initialized and configured.

[0007] Plan the touch measurement path based on the standard ball diameter and the measuring range of the probe.

[0008] Based on the touch detection path, the machine tool controls the probe to contact the standard spherical surface at a preset speed and record the coordinates.

[0009] According to the recorded coordinate data of the contact point, the sphere center coordinates and the standard sphere radius are fitted and calculated.

[0010] The probe radius compensation value is calculated according to the difference between the radius of the fitted standard sphere and the actual radius, and the probe of the machine tool is calibrated and controlled using the probe radius compensation value.

[0011] In a feasible implementation, the calibration trigger conditions include: first use, probe replacement, operation cycle threshold, temperature trigger threshold, and event trigger, wherein event trigger includes collision warning and continuous measurement error exceeding the limit.

[0012] In one possible implementation, initializing configuration of the calibration hardware includes:

[0013] Check the battery level of the probe, whether the probe is coaxial with the machine tool spindle axis, and the fixed installation position of the standard ball.

[0014] Switch the machine tool spindle speed mode to the preset speed and turn off the coolant.

[0015] In one feasible implementation, the touch probe path is planned based on the diameter of the standard ball and the measuring range of the probe, including:

[0016] Determine the coordinate constraint range of the touch point based on the standard ball diameter and the measuring range of the probe.

[0017] Based on the coordinate constraint range of the touch point, concentric circle path planning is performed on the XY plane to generate concentrically distributed touch points.

[0018] Based on the touch point coordinate constraint range, hierarchical path planning is performed on the Z axis to obtain a hierarchical touch point distribution.

[0019] The touch detection path is obtained by performing horizontal and vertical planning according to the concentrically distributed touch detection points and the layered touch detection point distribution.

[0020] In a feasible implementation, based on the touch point coordinate constraint range, concentric circle path planning is performed on the XY plane to generate concentrically distributed touch points, including:

[0021] According to the touch point coordinate constraint range, the feasible radius of the concentric circle is determined, and the feasible radius of the concentric circle is to ensure that all planned touch points meet the XY constraint.

[0022] Set the angle distribution rule, including uniform distribution, gradient non-uniform distribution, and random distribution.

[0023] Concentric circle segmentation is performed according to the angle distribution rule to determine the distribution angle interval.

[0024] The concentrically distributed touch points are generated according to the distribution angle intervals.

[0025] In a feasible implementation, based on the touch point coordinate constraint range, hierarchical path planning is performed on the Z axis to obtain a hierarchical touch point distribution, including:

[0026] According to the touch point coordinate constraint range, the number of layers at the Z-axis height within the constraint range is determined, and the number of layers includes at least three layers, namely, an equatorial layer, a top layer, and a bottom layer.

[0027] The Z axis is segmented into layered contact points according to the number of layers and the layer spacing to obtain the layered touch point distribution.

[0028] When the diameter of the standard ball exceeds the N-times threshold of the probe stroke, the surface of the standard ball is divided into multiple local layers, and each local layer is divided into layered contact points according to the number of layers to obtain a layered touch point distribution.

[0029] In a feasible implementation, the probe radius compensation value is calculated, and then the following steps are further included:

[0030] The angle distribution rule is changed to reset the distribution angle interval.

[0031] The probe radius compensation value is verified by using the recorded coordinate data of the reset distribution angle interval, and when the deviation is less than a threshold, the probe radius compensation value is determined.

[0032] In a feasible implementation, the coordinates of the sphere center and the radius of the standard sphere are fitted and calculated based on the recorded coordinate data of the contact point, including:

[0033] Fit the sphere center using the least squares method to minimize the sum of squared residuals:

[0034]

[0035] Among them, (X i , Y i , Z i ) is the recorded coordinate data of the i-th contact point, and the coordinates of the fitting sphere center (X c , Y c , Z c ), fitting radius R 测量 .

[0036] In a feasible implementation, the probe radius compensation value is calculated based on the difference between the radius of the fitted standard sphere and the actual radius, including:

[0037] The ambient temperature is detected by a temperature sensor.

[0038] Determine the temperature compensation coefficient based on the influence of historical temperature data.

[0039] The radius difference is compensated and corrected according to the ambient temperature and the temperature compensation coefficient to obtain the probe radius compensation value.

[0040] In a second aspect, the present invention further provides an automatic calibration control system for a machine tool probe, wherein the automatic calibration control system for a machine tool probe comprises:

[0041] The calibration judgment module is used to perform monitoring judgment using the calibration trigger conditions, and initialize the configuration of the calibration hardware when the trigger conditions are met.

[0042] The touch measurement path planning module is used to plan the touch measurement path based on the standard ball diameter and the measurement range of the probe.

[0043] The path execution and coordinate recording module is used to control the probe to contact the standard spherical surface at a preset speed and record the coordinates based on the touch detection path.

[0044] The spherical parameter calculation module is used to perform fitting calculations on the spherical center coordinates and the standard sphere radius based on the recorded coordinate data of the contact points.

[0045] The compensation calculation and calibration control module is used to calculate the probe radius compensation value according to the difference between the fitted standard sphere radius and the actual radius, and use the probe radius compensation value to calibrate and control the machine tool probe.

[0046] The present invention discloses an automatic calibration control method and system for a machine tool probe, comprising: monitoring and judging based on a set calibration trigger condition, and starting the initialization configuration process of the calibration hardware when it is determined that the trigger condition is met; planning a touch detection path according to the diameter parameter of the standard sphere and the measuring range of the probe; controlling the machine tool along the planned path so that the probe contacts the surface of the standard sphere at a preset speed, and recording the coordinate information of the contact point in real time; performing a fitting calculation of the standard sphere center position and radius based on the recorded contact point coordinate data; calculating the radius compensation value of the probe based on the difference between the fitted standard sphere radius and the actual standard sphere radius, and performing calibration control on the machine tool probe based on the compensation value. The automatic calibration control method and system for the machine tool probe disclosed in the present invention solve the technical problems of insufficient calibration accuracy, low calibration efficiency, and poor environmental adaptability, and achieve the technical effect of improving calibration accuracy and calibration efficiency and enhancing the environmental adaptability of calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of the flow of the automatic calibration control method of the machine tool probe of the present invention;

[0048] Figure 2 It is a structural schematic diagram of the automatic calibration control system of the machine tool probe of the present invention. DETAILED DESCRIPTION

[0049] The above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods of the specification to better understand the above technical solution. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention. It should be understood that the present invention is not limited to the example embodiments used only to explain the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In addition, it should be noted that, for the convenience of description, only the parts related to the present invention, rather than all, are shown in the drawings.

[0050] Example 1, as Figure 1 : is a flow chart of the automatic calibration control method of a machine tool probe of the present invention, wherein the automatic calibration control method of the machine tool probe comprises:

[0051] S100: Perform monitoring and judgment using calibration trigger conditions. When the trigger conditions are met, initialize the configuration of the calibration hardware.

[0052] Specifically, the calibration trigger conditions refer to a series of preset rules or events. When these rules or events occur, the calibration process is automatically started, and a series of basic settings are performed on the hardware devices involved in the calibration to ensure that they are in an initial state suitable for calibration work.

[0053] In some embodiments, the calibration trigger conditions include: first use, probe replacement, operation cycle threshold, temperature trigger threshold, and event trigger, wherein event trigger includes collision warning and continuous measurement error exceeding a limit.

[0054] Optionally, the calibration trigger conditions include:

[0055] First-time use trigger automatically triggers the calibration process when the measurement system or measuring device is put into use for the first time to ensure that the measurement reference in the initial state meets the preset standards.

[0056] Probe replacement trigger: When a measurement probe (probe) replacement event is detected, the calibration process is automatically triggered, including but not limited to replacing a probe of a different model or reinstalling a probe of the same model, to adapt to the physical parameter differences of different probes and ensure measurement consistency.

[0057] Operation cycle threshold trigger: When the continuous operation time or cumulative operation number of the measurement system reaches the preset cycle threshold, the calibration process is triggered. For example, it is set to automatically prompt or execute calibration after every 100 hours of operation or 10,000 measurements to prevent measurement accuracy drift caused by equipment wear, environmental changes, etc.

[0058] The temperature trigger threshold triggers the calibration process when the system ambient temperature changes by more than the preset temperature threshold. For example, when the temperature changes by more than ±5°C, the calibration process is triggered to eliminate the impact of temperature changes on the measurement system structure and electronic component performance, ensuring measurement stability.

[0059] Event triggering triggers the calibration process when specific abnormal events are detected. Events include but are not limited to: when the measurement system detects a potential collision risk or an actual minor collision, calibration is triggered to verify and restore the correctness of the probe position and system parameters; continuous measurement error exceeding limit events, when multiple consecutive measurement results deviate from the preset error tolerance range, calibration is triggered, for example, if the measurement error exceeds the set threshold of ±0.05mm for 5 consecutive times, potential system drift or failure can be corrected in time to prevent the error from accumulating and expanding.

[0060] In some embodiments, initializing configuration of the calibration hardware includes:

[0061] Check the probe battery level, whether the probe is coaxial with the machine spindle axis, and whether the standard ball is fixed in the installation position; switch the machine spindle operating speed mode to the preset speed and turn off the coolant.

[0062] Specifically, the initialization configuration includes checking whether the probe battery is sufficient, confirming the coaxiality of the probe and the machine tool spindle axis, verifying whether the fixed installation position of the standard ball is correct, switching the machine tool spindle's operating speed mode to the preset speed and turning off the coolant system to reduce external factors from interfering with the calibration process.

[0063] Checking the probe battery level ensures sufficient power throughout the calibration process, preventing interruptions due to low battery. Verifying the coaxiality of the probe with the machine tool spindle axis ensures the probe's positional accuracy during measurement and reduces measurement errors caused by positional deviation. Confirming the correct installation position of the calibration ball ensures the probe's accuracy when contacting the calibration ball. Switching the machine tool spindle to a preset speed and turning off the coolant creates a stable, controllable calibration environment to prevent coolant flow from affecting probe measurement.

[0064] After completing these initial configurations, the calibration hardware is in optimal condition and can accurately perform subsequent calibration tasks such as touch path planning and coordinate recording, thereby improving the reliability and accuracy of the entire calibration process.

[0065] S200: Plan the touch measurement path based on the standard ball diameter and the measuring range of the probe.

[0066] Specifically, a probe contact path is designed based on the diameter of the standard sphere and the probe's measuring range. This ensures that the probe can fully contact the standard sphere within the probe's measuring range, along a reasonable and efficient path. This allows for sufficient and accurate measurement data to ensure the accuracy of subsequent calibration calculations.

[0067] Among them, the diameter of the standard sphere is the geometric dimension of the standard sphere used for calibration, which determines the spatial range of the standard sphere; the measurement range of the probe refers to the spatial range that the probe can effectively measure, that is, the spatial area that the probe can reach and measure.

[0068] In some embodiments, planning a touch path based on the diameter of the standard ball and the measuring range of the probe includes:

[0069] According to the diameter of the standard sphere and the measuring range of the probe, the coordinate constraint range of the touch point is determined; based on the coordinate constraint range of the touch point, concentric circle path planning is performed on the XY plane to generate concentrically distributed touch points; based on the coordinate constraint range of the touch point, layered path planning is performed on the Z axis to obtain a layered touch point distribution; horizontal and vertical planning is performed according to the concentrically distributed touch points and the layered touch point distribution to obtain the touch path.

[0070] Specifically, the touch point refers to a spatial coordinate point planned for performing an actual contact or measurement operation, and the touch path is a track connecting multiple touch points in a certain order.

[0071] Specifically, first, based on the diameter D of the standard sphere and the maximum measurement range R of the probe, the spatial area that the probe can effectively reach is calculated as the constraint range of the touch point coordinates; for example, it can be limited to a spherical shell area with a radius of R+0.5D centered on the center of the standard sphere. Then, within the above constraint range, based on the XY plane where the center of the standard sphere is located, concentric circle path planning is performed in combination with the set radius range and distribution rules of the concentric circles (such as uniform distribution, gradient distribution, etc.) to generate several concentric circles with increasing radius, where touch points are evenly arranged on each circumference to form concentrically distributed touch points. At the same time, the constraint area is highly layered along the Z-axis direction (perpendicular to the XY plane), and concentric circle touch points are distributed at each height layer to form a layered touch point distribution, thereby achieving three-dimensional coverage of the standard sphere.

[0072] For example, if the diameter of the standard ball is R=25 mm, the side head measurement range is:

[0073] X-axis: ±ΔX (ΔX=8 mm); Y-axis: ±ΔY (ΔY=6.5 mm); X-axis: ±ΔZ (ΔZ=7 mm).

[0074] Then, the coordinate constraint range can be formulated as:

[0075] X coordinate constraint: X0-ΔX≤X i ≤X0+ΔX;

[0076] Y coordinate constraint: Y0-ΔY≤Y i ≤Y0+ΔY;

[0077] Z coordinate constraint: Z0-ΔZ≤Zi ≤Z0+ΔZ;

[0078] Among them, (X i ,Y i ,Z i ) are the center coordinates of the standard sphere, usually the origin of the standard sphere.

[0079] Furthermore, the XY plane concentric circle path and the Z axis layered path are planned in a horizontal and vertical linkage; a reasonable connection strategy (such as spiral, zigzag, Z-shaped, etc.) is used to connect all touch points; and finally a complete spatial touch path trajectory is formed.

[0080] The above-mentioned path planning process enables the probe to efficiently and comprehensively touch the surface of the standard sphere in a preset order and direction, providing high-quality measurement data for subsequent calculations of the sphere center coordinates and radius fitting.

[0081] In some implementations, based on the touch point coordinate constraint range, concentric circle path planning is performed on the XY plane to generate concentrically distributed touch points, including:

[0082] According to the coordinate constraint range of the touch point, the feasible radius of the concentric circle is determined, and the feasible radius of the concentric circle is to ensure that all planned touch points meet the XY constraint; set the angle distribution rules, including uniform distribution, gradient non-uniform distribution, and random distribution; divide the concentric circles according to the angle distribution rules and determine the distribution angle interval; generate the concentrically distributed touch points according to the distribution angle interval.

[0083] Specifically, the concentric circle radius is the radius of the concentric circle within the XY plane that can accommodate all touch points, determined based on the touch point coordinate constraints. These radii ensure that all planned touch points are within the effective measurement range of the probe and do not exceed the surface of the standard sphere.

[0084] Specifically, the angular distribution rule refers to the distribution of touch points along the concentric circular path, including uniform distribution, gradient non-uniform distribution, and random distribution. Uniform distribution means that the touch points are evenly spaced around the circumference; gradient non-uniform distribution means that the touch points are denser in some areas and sparser in others; and random distribution means that the touch points are randomly selected around the circumference. For example, if uniform coverage is required, choose uniform distribution; if high-density detection is required in the central area, choose gradient non-uniform distribution; and if the target surface is irregular, use random distribution to enhance coverage diversity.

[0085] Specifically, according to the selected angle distribution rule, the concentric circles can be divided into a number of sector-shaped areas, wherein the included angle of each sector-shaped area is the distribution angle interval, which is used to determine the specific position of the touch point.

[0086] Furthermore, for each concentric circle, that is, on each radius, the coordinates of the touch points at each angular position are calculated in sequence, and the corresponding touch points are generated as XY plane touch points to be input into the subsequent path integration step.

[0087] The above method can flexibly adapt to the measurement accuracy requirements of different areas by setting different angle distribution rules. At the same time, it is no longer limited to fixed angle intervals, which improves the flexibility of path planning.

[0088] In some implementations, performing hierarchical path planning on the Z axis based on the touch point coordinate constraint range to obtain a hierarchical touch point distribution includes:

[0089] According to the coordinate constraint range of the touch point, the number of layers in the Z-axis height within the constraint range is determined, and the number of layers includes at least three layers, namely the equatorial layer, the top layer, and the bottom layer; the Z-axis is divided into layered contact points according to the number of layers and the layer spacing to obtain the layered touch point distribution; when the diameter of the standard ball exceeds the N times threshold of the probe stroke, the surface of the standard ball is divided into multiple local layer areas, and the layered contact points of each local layer area are divided according to the number of layers to obtain the layered touch point distribution.

[0090] Specifically, first, the number of layers in the Z-axis direction is determined based on the coordinate constraints of the touch point. The number of layers includes at least three layers: the equatorial layer, which is the middle layer where the maximum diameter of the standard sphere is located; the top layer, which is the upper layer of the upper hemisphere area of the standard sphere; and the bottom layer, which is the lower layer of the lower hemisphere area of the standard sphere. Optionally, the number of intermediate layers can be further increased to form a multi-layer structure based on the probe travel capacity and measurement accuracy requirements. The standard sphere is then layered along the Z-axis based on the number of layers and the spacing between layers. This means that the concentric circle touch point distribution on the XY plane is replicated at each layer height. The replicated touch points are then matched with the surface of the standard sphere at that height, and the matching touch points are selected as the layered touch point distribution in three-dimensional space.

[0091] Optionally, when the diameter of the standard sphere exceeds a threshold of N times the stylus stroke, for example, if the diameter of the standard sphere is 60mm and the stylus stroke is only ±8mm, the stylus cannot fully touch the entire area of the standard sphere at one time. In this case, the surface of the standard sphere is divided into multiple local layers, and each local layer is further divided into layered contact points according to the number of layers. After the touch measurement is completed in each local area, local accuracy verification is performed to check whether the coordinate data of the touch points in the area meet the expected accuracy requirements, for example, whether the measurement error of the stylus radius of the stylus is within the allowable range. If the local accuracy does not meet the requirements, the local area needs to be touched again.

[0092] Optionally, after completing the touch measurement and coordinate stitching of all local areas, perform overall fitting accuracy verification. Use the fitted standard sphere center coordinates and probe stylus radius and other parameters to calculate the overall measurement error to ensure that the overall measurement error meets the calibration accuracy requirements. For example, the sphere center coordinate error should be within ±0.005mm, and the stylus radius error should be within ±0.001mm. For example, a fitting algorithm (such as the least squares method) is used to fit the standard sphere center coordinates and stylus radius.

[0093] If the overall accuracy does not meet the requirements, you can go back to the local area and re-touch or adjust the fitting algorithm.

[0094] The aforementioned Z-axis hierarchical path planning steps effectively address calibration issues when the standard sphere diameter is significantly larger than the probe travel, significantly improving calibration adaptability and accuracy. First, hierarchical path planning ensures comprehensive probe contact measurements at varying heights, avoiding measurement blind spots caused by excessively large standard sphere diameters. Second, a dual verification mechanism of local accuracy verification and overall fitting accuracy verification ensures that both the measurement accuracy of each local area and the overall measurement accuracy meet calibration requirements.

[0095] S300: Based on the touch detection path, the machine tool controls the probe to contact the standard spherical surface at a preset speed and record the coordinates.

[0096] Specifically, the touch detection path (including the XYZ three-dimensional coordinate point sequence) is input into the machine tool CNC system, and the target machine tool is controlled to drive the probe to move along the preset trajectory according to the path point sequence; at each touch detection point position, the probe is controlled to contact the standard sphere at a preset speed, wherein the preset speed can be set according to factors such as the probe type, the probe rigidity, and the surface material, for example: the contact speed is 2mm / s, and the retraction speed is 5mm / s; at the moment the probe contacts the standard sphere, the data acquisition module is triggered; the spatial position coordinates of the current probe are automatically collected and recorded, wherein the coordinates can be obtained in real time through the machine tool encoder, the probe feedback signal, or the edge computing module; finally, the coordinate data of all touch detection points are stored in the local cache or uploaded to the edge computing unit for subsequent processing.

[0097] S400: performing fitting calculation of the sphere center coordinates and the standard sphere radius according to the recorded coordinate data of the contact point.

[0098] In some embodiments, the spherical center coordinates and the standard sphere radius fitting calculation are performed based on the recorded coordinate data of the contact point, including:

[0099] Fit the sphere center using the least squares method to minimize the sum of squared residuals:

[0100]

[0101] Among them, (Xi , Y i , Z i ) is the recorded coordinate data of the i-th contact point, and the coordinates of the fitting sphere center (X c , Y c , Z c ), fitting radius R 测量 .

[0102] Specifically, the spatial coordinate data of multiple touch points are fitted and calculated to obtain the center coordinates and radius of the standard sphere:

[0103] Assume that n valid touch point coordinate data have been obtained, recorded as:

[0104] P i =(X i ,Y i ,Z i ),i=1,2,...,n;

[0105] Assume that the coordinates of the center of the fitting sphere are C=(X c , Y c , Z c ), the radius of the fitting sphere is R 测量 , then the Euclidean distance from the i-th touch point to the center of the sphere is:

[0106]

[0107] The residual is defined as:

[0108] ε i =d i -R 测量 ;

[0109] The objective function to be minimized is the residual sum of squares:

[0110]

[0111] Since the above objective function is a nonlinear least squares problem, numerical solution methods such as algebraic linearization method and iterative optimization method (such as Gauss-Newton method) can be used to obtain the standard sphere radius fitting calculation results.

[0112] In the above fitting method, the mathematical model based on the least squares method ensures the minimum global error and can adapt to touch points of different numbers, distributions and accuracies; at the same time, it supports the integration of automated measurement systems and can be embedded in edge computing modules to achieve real-time fitting and error feedback.

[0113] S500: Calculating a probe radius compensation value according to a difference between the radius of the fitted standard sphere and the actual radius, and calibrating and controlling the machine tool probe using the probe radius compensation value.

[0114] Specifically, the fitted standard sphere radius is the radius of the standard sphere calculated using the least squares fitting method, while the actual radius is the true radius of the standard sphere. There may be a slight difference between these two values. The difference between the fitted and actual radii is used to calculate a value to correct for probe measurement errors, known as the probe radius compensation value. This value is used to adjust the machine tool probe to ensure measurement accuracy.

[0115] Specifically, the probe radius compensation value is applied to the calibration parameters of the probe; the machine tool numerical control system (CNC) or the probe control module is controlled, and the compensation value can be used for: radius offset correction of subsequent spatial measurement data; direct modification of the probe compensation parameter table (such as G43, G41 / G42 and other tool compensation parameters) or real-time error correction in the edge computing module.

[0116] Preferably, the compensation process can be integrated into an automatic closed-loop control process: touch the standard sphere and fit the center and radius; calculate the radius difference; determine whether it exceeds the tolerance (such as ±0.002mm); if it exceeds the tolerance, automatically update the probe compensation parameters and prompt the user; if it is within the tolerance, maintain the current settings.

[0117] In some embodiments, calculating the probe radius compensation value according to the difference between the radius of the fitted standard sphere and the actual radius includes:

[0118] The ambient temperature is detected by a temperature sensor; a temperature compensation coefficient is determined according to the influence relationship of historical temperature data; and the radius difference is compensated and corrected according to the ambient temperature and the temperature compensation coefficient to obtain the probe radius compensation value.

[0119] Specifically, the ambient temperature factor is introduced in the probe radius compensation calculation process. The current ambient temperature is detected by a temperature sensor, and combined with the historical temperature influence model, the temperature compensation correction is performed on the difference between the fitting radius and the standard radius to obtain a more accurate probe radius compensation value.

[0120] Specifically, first, the current ambient temperature is collected in real time by using a temperature sensor installed in the measurement environment or near the probe body; then, based on historical experimental data or system calibration, a model for the impact of temperature changes on the probe radius error is established, including a linear impact model or a nonlinear impact model (which can be obtained by empirical formulas, experimental fitting or machine learning models); combined with the current ambient temperature and the temperature compensation coefficient, the difference between the fitted radius and the actual radius is compensated and corrected.

[0121] Specifically, if ambient temperature changes cause the probe or calibration sphere to expand or contract, the temperature compensation coefficient is used to adjust the radius difference, resulting in a more accurate probe radius compensation value. By using this radius difference compensation correction process based on ambient temperature and the temperature compensation coefficient, this solution significantly improves the environmental adaptability and accuracy of the calibration results.

[0122] In some embodiments, calculating the probe radius compensation value further includes:

[0123] The angle distribution rule is changed and the distribution angle interval is reset; the probe radius compensation value is verified using the recorded coordinate data of the reset distribution angle interval, and when the deviation is less than a threshold, the probe radius compensation value is determined.

[0124] Specifically, after calculating the probe radius compensation value, the touch point data is recollected by changing the angular distribution rule of the standard ball touch path, and the validity of the compensation value is verified based on the data, thereby improving the reliability and robustness of the probe compensation result.

[0125] Specifically, the angular distribution rules are first reset. For example, the interval between the polar angle and the azimuth angle is changed (e.g., from 15° to 10°), and asymmetric sampling or local dense sampling strategies are introduced to avoid fitting deviations or local errors caused by a single angular distribution. Then, the calculated compensation value is applied to re-touch the standard sphere, collect new coordinate points, and re-fit the sphere using the compensated probe parameters to obtain a new radius. Next, the deviation is verified by calculating the new radius. If the deviation is less than the threshold, the compensation value is confirmed to be valid. Otherwise, the compensation value needs to be readjusted or re-sampling is required.

[0126] Through the above process, a closed-loop verification mechanism is implemented to avoid incorrect compensation due to single fitting errors, thereby improving the robustness and stability of the compensation value; at the same time, the touch detection strategy can be dynamically adjusted to adapt to different probe states or environmental conditions.

[0127] In summary, the automatic calibration control method for a machine tool probe provided by the present invention has the following technical effects:

[0128] The monitoring and judgment are carried out through the set calibration trigger conditions. When the trigger conditions are determined to be met, the initialization configuration process of the calibration hardware is started; the touch detection path is planned according to the diameter parameters of the standard sphere and the measuring range of the probe; along the planned path, the machine tool is controlled to make the probe contact the surface of the standard sphere at a preset speed, and the coordinate information of the contact point is recorded in real time; based on the recorded contact point coordinate data, the standard sphere center position and radius are fitted and calculated; based on the difference between the fitted standard sphere radius and the actual standard sphere radius, the radius compensation value of the probe is calculated, and calibration control is performed on the machine tool probe based on the compensation value, thereby achieving the technical effect of improving calibration accuracy and calibration efficiency and enhancing the environmental adaptability of calibration.

[0129] Example 2, as Figure 2 Schematic diagram of the structure of the automatic calibration control system of the machine tool probe of the present invention. Figure 1 The flow chart of the automatic calibration control method of the machine tool probe of the present invention can be shown as follows: Figure 2 The structure shown is implemented.

[0130] Based on the same concept as the automatic calibration control method of the machine tool probe in the above embodiment, the present invention also provides an automatic calibration control system for the machine tool probe, including:

[0131] The calibration determination module 11 is configured to perform monitoring and determination using calibration trigger conditions, and initialize configuration of calibration hardware when the trigger conditions are met.

[0132] The touch detection path planning module 12 is used to plan the touch detection path according to the diameter of the standard ball and the measuring range of the probe.

[0133] The path execution and coordinate recording module 13 is used to control the probe to contact the standard sphere at a preset speed and record the coordinates based on the touch detection path.

[0134] The sphere parameter calculation module 14 is used to perform fitting calculations on the sphere center coordinates and the standard sphere radius based on the recorded coordinate data of the contact points.

[0135] The compensation calculation and calibration control module 15 is used to calculate the probe radius compensation value according to the difference between the radius of the fitted standard sphere and the actual radius, and to perform calibration control on the machine tool probe using the probe radius compensation value.

[0136] In some embodiments, the calibration trigger conditions in the calibration determination module 11 include: first use, probe replacement, operation cycle threshold, temperature trigger threshold, and event trigger, wherein event trigger includes collision warning and continuous measurement error exceeding the limit.

[0137] In some embodiments, the calibration determination module 11 further includes:

[0138] The probe status and installation inspection unit is used to check the probe battery power, the coaxiality of the probe and the machine tool spindle axis, and the fixed installation position of the standard ball.

[0139] The machine tool spindle operation mode switching unit is used to switch the machine tool spindle operation speed mode to a preset speed and turn off the coolant.

[0140] In some embodiments, the touch path planning module 12 includes:

[0141] The touch point coordinate constraint range determination unit is used to determine the touch point coordinate constraint range according to the standard ball diameter and the measuring range of the probe.

[0142] The XY plane concentric circle path planning unit is used to perform concentric circle path planning on the XY plane based on the touch point coordinate constraint range to generate concentrically distributed touch points.

[0143] The Z-axis hierarchical path planning unit is used to perform hierarchical path planning on the Z-axis based on the touch point coordinate constraint range to obtain the hierarchical touch point distribution.

[0144] The touch path horizontal and vertical planning unit is used to perform horizontal and vertical planning according to the concentric distribution of touch points and the layered distribution of touch points to obtain the touch path.

[0145] In some implementations, the steps of executing the XY plane concentric circle path planning unit in the touch path planning module 12 include:

[0146] According to the touch point coordinate constraint range, the feasible radius of the concentric circle is determined, and the feasible radius of the concentric circle is to ensure that all planned touch points meet the XY constraint.

[0147] Set the angle distribution rule, including uniform distribution, gradient non-uniform distribution, and random distribution.

[0148] Concentric circle segmentation is performed according to the angle distribution rule to determine the distribution angle interval.

[0149] The concentrically distributed touch points are generated according to the distribution angle intervals.

[0150] In some implementations, the steps executed by the Z-axis hierarchical path planning unit in the touch path planning module 12 include:

[0151] According to the touch point coordinate constraint range, the number of layers at the Z-axis height within the constraint range is determined, and the number of layers includes at least three layers, namely, an equatorial layer, a top layer, and a bottom layer.

[0152] The Z axis is segmented into layered contact points according to the number of layers and the layer spacing to obtain the layered touch point distribution.

[0153] When the diameter of the standard ball exceeds the N-times threshold of the probe stroke, the surface of the standard ball is divided into multiple local layers, and each local layer is divided into layered contact points according to the number of layers to obtain a layered touch point distribution.

[0154] In some embodiments, the steps executed by the ball parameter calculation module 14 include:

[0155] Fit the sphere center using the least squares method to minimize the sum of squared residuals:

[0156]

[0157] Among them, (X i, Y i , Z i ) is the recorded coordinate data of the i-th contact point, and the coordinates of the fitting sphere center (X c , Y c , Z c ), fitting radius R 测量 .

[0158] In some embodiments, the compensation calculation and calibration control module 15 includes:

[0159] The ambient temperature detection unit is used to detect the ambient temperature through a temperature sensor.

[0160] The temperature compensation coefficient determination unit is used to determine the temperature compensation coefficient according to the influence relationship of historical temperature data.

[0161] The radius difference compensation correction unit is used to compensate and correct the radius difference according to the ambient temperature and the temperature compensation coefficient to obtain the probe radius compensation value.

[0162] In some embodiments, the compensation calculation and calibration control module 15 further includes:

[0163] The angle distribution rule changing and interval resetting unit is used to change the angle distribution rule and reset the distribution angle interval.

[0164] The probe radius compensation value verification unit is used to verify the probe radius compensation value by using the recorded coordinate data of the reset distribution angle interval, and determine the probe radius compensation value when the deviation is less than a threshold.

[0165] It should be understood that the embodiments mentioned in this specification focus on their differences from other embodiments. The specific embodiments in the aforementioned embodiment 1 are also applicable to the automatic calibration control system of the machine tool probe described in embodiment 2. For the sake of brevity of the specification, they will not be further elaborated here.

[0166] It should be understood that the embodiments disclosed in the present invention and the above description can enable those skilled in the art to use the present invention to implement the present invention. At the same time, the present invention is not limited to the embodiments mentioned above. It should be understood that those skilled in the art can still modify the technical solutions described in the above embodiments or replace some of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention and are all included in the scope of protection of the present invention.

Claims

1. Automatic calibration control method for machine tool probe, characterized in that: include: Use the calibration trigger conditions to perform monitoring and judgment, and when the trigger conditions are met, initialize the configuration of the calibration hardware; Plan the touch measurement path based on the standard ball diameter and the measuring range of the probe; Based on the touch detection path, the machine tool controls the probe to contact the standard spherical surface at a preset speed and record the coordinates; According to the recorded coordinate data of the contact point, the sphere center coordinates and the standard sphere radius are fitted and calculated; The probe radius compensation value is calculated according to the difference between the radius of the fitted standard sphere and the actual radius, and the probe of the machine tool is calibrated and controlled using the probe radius compensation value.

2. The automatic calibration control method for a machine tool probe according to claim 1, characterized in that: The calibration trigger conditions include: first use, probe replacement, operation cycle threshold, temperature trigger threshold, and event trigger, where event trigger includes collision warning and continuous measurement error exceeding the limit.

3. The automatic calibration control method for a machine tool probe according to claim 2, characterized in that: Initial configuration of the calibration hardware, including: Check the probe battery level, whether the probe is coaxial with the machine tool spindle axis, and the fixed installation position of the standard ball; Switch the machine tool spindle speed mode to the preset speed and turn off the coolant.

4. The automatic calibration control method for a machine tool probe according to claim 1, characterized in that: Plan the touch path based on the standard ball diameter and the measuring range of the probe, including: Determine the coordinate constraint range of the touch point based on the standard ball diameter and the measuring range of the probe; Based on the coordinate constraint range of the touch point, concentric circle path planning is performed on the XY plane to generate concentrically distributed touch points; Based on the coordinate constraint range of the touch point, a hierarchical path planning is performed on the Z axis to obtain a hierarchical touch point distribution; The touch detection path is obtained by performing horizontal and vertical planning according to the concentrically distributed touch detection points and the layered touch detection point distribution.

5. The automatic calibration control method for a machine tool probe according to claim 4, characterized in that: Based on the coordinate constraint range of the touch point, concentric circle path planning is performed on the XY plane to generate concentrically distributed touch points, including: Determine the feasible radius of the concentric circle according to the coordinate constraint range of the touch point, and the feasible radius of the concentric circle is to ensure that all planned touch points meet the XY constraint; Set angle distribution rules, including uniform distribution, gradient non-uniform distribution, and random distribution; Perform concentric circle segmentation according to the angle distribution rule to determine the distribution angle interval; The concentrically distributed touch points are generated according to the distribution angle intervals.

6. The automatic calibration control method for a machine tool probe according to claim 5, characterized in that: Based on the coordinate constraint range of the touch point, hierarchical path planning is performed on the Z axis to obtain a hierarchical touch point distribution, including: Determining the number of layers in the Z-axis height within the constraint range according to the touch point coordinate constraint range, wherein the number of layers includes at least three layers, namely, an equatorial layer, a top layer, and a bottom layer; Performing layered contact point segmentation on the Z axis according to the number of layers and the layer spacing to obtain the layered touch point distribution; When the diameter of the standard ball exceeds the N-times threshold of the probe stroke, the surface of the standard ball is divided into multiple local layers, and each local layer is divided into layered contact points according to the number of layers to obtain a layered touch point distribution.

7. The automatic calibration control method for a machine tool probe according to claim 5, characterized in that: Calculates the probe radius compensation value, followed by: Changing the angle distribution rule and resetting the distribution angle interval; The probe radius compensation value is verified by using the recorded coordinate data of the reset distribution angle interval, and when the deviation is less than a threshold, the probe radius compensation value is determined.

8. The automatic calibration control method for a machine tool probe according to claim 1, characterized in that: According to the recorded coordinate data of the contact point, the sphere center coordinates and the standard sphere radius fitting calculation are performed, including: Fit the sphere center using the least squares method to minimize the sum of squared residuals: Among them, (X i , Y i , Z i ) is the recorded coordinate data of the i-th contact point, and the coordinates of the fitting sphere center (X c , Y c , Z c ), fitting radius R 测量 .

9. The automatic calibration control method for a machine tool probe according to claim 8, characterized in that: Calculate the probe radius compensation value based on the difference between the fitted standard sphere radius and the actual radius, including: Detect the ambient temperature through the temperature sensor; Determine the temperature compensation coefficient based on the influence of historical temperature data; The radius difference is compensated and corrected according to the ambient temperature and the temperature compensation coefficient to obtain the probe radius compensation value.

10. Automatic calibration control system for machine tool probe, characterized in that: The automatic calibration control method for a machine tool probe according to any one of claims 1 to 9 comprises: A calibration determination module is used to perform monitoring and determination using calibration trigger conditions, and initialize the configuration of the calibration hardware when the trigger conditions are met; The touch test path planning module is used to plan the touch test path based on the standard ball diameter and the measuring range of the probe; A path execution and coordinate recording module, configured to control the probe to contact the standard spherical surface at a preset speed and record the coordinates based on the touch detection path through the machine tool; The ball parameter calculation module is used to calculate the sphere center coordinates and the standard sphere radius according to the recorded coordinate data of the contact point; The compensation calculation and calibration control module is used to calculate the probe radius compensation value according to the difference between the fitted standard sphere radius and the actual radius, and use the probe radius compensation value to calibrate and control the machine tool probe.

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