Device and method for detecting straightness of ultra-precise hydrostatic guideway

Abstract

The invention discloses a device and a method for detecting the straightness of an ultra-precise hydrostatic guideway, and the device comprises a calibration part, the calibration surface of which is configured to be perpendicular to a first guideway surface or a second guideway surface in a to-be-detected plane of the hydrostatic guideway, so as to adapt to the measurement in different directions, and the first guideway surface is perpendicular to the second guideway surface; and the displacement sensor is fixed on the sliding plate, and a measuring head of the displacement sensor is perpendicular to the calibration surface, so that the displacement sensor and the calibration surface form a non-contact measurement pair in the moving process of the sliding plate, and displacement data are obtained by sensing the change of the distance between the displacement sensor and the calibration surface. According to the detection device, the displacement sensor and the calibration piece are adopted to form a non-contact measurement pair, so that high-repeatability measurement is realized by virtue of nanoscale precision of the sensor while a contact force error is eliminated.

Description

Technical Field

[0001] This invention relates to the field of precision instrument testing technology, specifically to a device and method for testing the straightness of ultra-precision hydrostatic guide rails. Background Technology

[0002] Optical aspherical ultra-precision composite machining centers are key equipment for manufacturing high-end optical components. The linear motion accuracy of their guideways directly determines the surface accuracy and surface quality of the machined parts. While hydrostatic guideways are the preferred choice for these machines due to their high rigidity, high precision, and frictionless operation, the detection of their straightness error remains a challenge for assembly and precision assurance. Currently, commonly used non-contact methods such as laser interferometers and electronic levels suffer from high equipment costs, sensitivity to environmental vibrations, and complex installation and debugging. Contact measurements, such as dial indicators, are prone to introducing deformation and human error due to contact force, and pose a risk of scratching precision surfaces. Therefore, a fast, stable, and repeatable high-precision straightness detection method is urgently needed in machine tool assembly areas. Summary of the Invention

[0003] In view of the above problems, the present invention is proposed to provide a device and method for detecting the straightness of ultra-precision hydrostatic guideways that overcomes or at least partially solves the above problems.

[0004] According to one aspect of the present invention, a device for detecting the straightness of an ultra-precision hydrostatic guide rail is provided. The hydrostatic guide rail includes a guide assembly and a motion assembly. The motion assembly includes at least a sliding plate, which is suspended by a hydrostatic oil film and adapted to reciprocate linearly along the guide assembly. The detection device includes: a calibration member, the calibration surface of which is configured to be arranged perpendicularly to a first guide rail surface or a second guide rail surface in the plane to be measured of the hydrostatic guide rail, to adapt to measurements in different directions, wherein the first guide rail surface and the second guide rail surface are perpendicular to each other; and a displacement sensor, fixed to the sliding plate, the probe of which is perpendicular to the calibration surface, such that during the movement of the sliding plate, the displacement sensor and the calibration surface form a non-contact measurement pair, and displacement data is obtained by sensing the change in the distance between the sensor and the calibration surface.

[0005] Optionally, the detection device according to the present invention further includes: a calibration piece fixing frame, including a first base and a first support base; the first base is bolted to the machine tool bed that carries the hydrostatic guide rail; the first support base is fixed on the first base and is used to support the calibration piece, so that its calibration surface is perpendicular to the probe of the displacement sensor.

[0006] Optionally, the detection device according to the present invention further includes: a sensor mounting bracket, including a second base and a second support base; the second base is bolted to the slide plate; the second support bracket is movably disposed on the second base for supporting the displacement sensor and adjusting the distance between the probe of the displacement sensor and the calibration surface of the calibration piece.

[0007] Optionally, in the detection device according to the invention, the distance between the probe of the displacement sensor and the calibration surface of the calibration element is 6 mm to 10 mm.

[0008] Optionally, in the testing apparatus according to the invention, the standard component includes: a stone foot and a stone foot seat; the working surface of the stone foot constitutes the calibration surface, and the stone foot is mounted and positioned on the calibration component holder via the stone foot seat.

[0009] Optionally, in the detection device according to the invention, the standard component further includes: a shim, movably disposed between the stone foot and the stone foot seat, for adjusting the installation position of the stone foot.

[0010] Optionally, in the detection device according to the present invention, the displacement sensor is a spectral confocal displacement sensor.

[0011] Optionally, the detection device according to the present invention further includes: a data processor, electrically connected to the displacement sensor, for receiving displacement data collected by the displacement sensor and processing the displacement data to obtain the straightness of the plane measured by the hydrostatic guide rail.

[0012] Optionally, in the detection device according to the present invention, the data processor is configured with an error compensation program, which is an algorithm based on MATLAB, used to eliminate errors caused by the tilt of the calibrator installation.

[0013] According to another aspect of the present invention, a method for detecting the straightness of an ultra-precision hydrostatic guide rail is provided, implemented by the aforementioned detection device. The method includes: installing a calibration component and a displacement sensor of the detection device correspondingly to the determined test plane of the hydrostatic guide rail; starting the hydrostatic guide rail and causing the slide plate to drive the displacement sensor to perform at least three full-stroke reciprocating motions along the guide rail; during the full-stroke reciprocating motion, using the displacement sensor to collect the change in distance between the sensor and the calibration surface as displacement data; and processing the displacement data using a data processor to obtain the straightness of the plane being measured by the hydrostatic guide rail.

[0014] According to the present invention, a non-contact measurement pair is formed by a displacement sensor and a calibration component, which eliminates contact force error and achieves high repeatability measurement with the nanometer-level precision of the sensor.

[0015] Meanwhile, a quick-assembly and sturdy tooling bracket was designed to ensure the applicability and high efficiency of the device on the assembly site. Ultimately, this invention integrates the advantages of non-contact measurement and rapid on-site assembly and adjustment, achieving an optimal balance in terms of cost, accuracy, efficiency, and reliability.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the structure of an optical aspherical ultra-precision composite machining center 1000 in the prior art is shown; Figure 2 A schematic diagram of the structure of a device 2000 for detecting the straightness of an ultra-precision hydrostatic guide rail according to an embodiment of the present invention is shown; Figure 3 A schematic diagram of the structure of a detection device 2000 according to another embodiment of the present invention is shown; Figure 4 A schematic diagram showing the spatial positions of the calibration element 2100 and the calibration element holder 2300 according to an embodiment of the present invention is shown; Figure 5 A schematic diagram showing the spatial positions of displacement sensor 2200 and sensor 2400 according to an embodiment of the present invention is shown; Figure 6 A schematic diagram showing the spatial positions of the calibration element 2100 and the calibration element holder 2300 according to another embodiment of the present invention is shown; Figure 7 A schematic diagram of the spatial positions of displacement sensor 2200 and sensor 2400 according to another embodiment of the present invention is shown; Figure 8 A schematic diagram of the structure of a calibration element 2100 according to an embodiment of the present invention is shown; Figure 9 A schematic diagram of a method 3000 for detecting the straightness of an ultra-precision hydrostatic guide rail according to an embodiment of the present invention is shown. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0019] Figure 1 A schematic diagram of the structure of a prior art optical aspherical ultra-precision composite machining center 1000 is shown. Figure 1 As shown, the optical aspherical ultra-precision composite machining machine tool 1000 includes an X-axis guide rail 1100, a Z-axis guide rail 1200, and a machine tool body 1300.

[0020] Among them, the X-axis guide rail 1100 and the Z-axis guide rail 1200 are both hydrostatic guide rails, and the hydrostatic guide rails include a guide component and a motion component. The motion component includes at least a sliding plate, which is suspended by a hydrostatic oil film and is suitable for reciprocating linear motion along the guide component.

[0021] Hydrostatic guideways, with their superior characteristics such as high rigidity, high precision, and frictionless operation, have become core functional components of ultra-precision machine tools. However, ensuring the straightness accuracy and efficient testing of these guideways during assembly and use remains a technical bottleneck restricting the improvement of overall machine performance.

[0022] Currently, the industry mainly relies on two technical approaches for detecting this straightness error, but both have significant limitations: 1. High-precision non-contact measurement (such as laser interferometers, electronic levels): While such methods can theoretically achieve high-precision measurements, their application in actual machine tool assembly and debugging environments faces significant challenges: The equipment is expensive, which makes it difficult to control the overall cost and maintenance expenses; It is extremely sensitive to environmental vibration, airflow and temperature fluctuations, and has poor stability in typical industrial workshop environments, making measurement data prone to distortion. The installation and debugging process is complex and time-consuming, requiring professional personnel to operate, which makes it difficult to meet the urgent needs of production sites for testing efficiency.

[0023] 2. Traditional contact measurement (such as dial indicator): While this method is simple and intuitive, its inherent contact measurement principle introduces systemic errors and risks that cannot be ignored. Contact force can easily cause minute deformations on the precision guide surface, introducing measurement errors. It heavily relies on the operator's experience and skills, resulting in large human error and poor measurement repeatability; There is a risk of scratching the surface of the precision guide rail, which may cause irreversible damage to the workpiece.

[0024] To address the problems existing in the prior art, the present invention is proposed. This application proposes a detection device for the straightness of ultra-precision hydrostatic guideways. This device uses a displacement sensor and a calibration component to form a non-contact measurement pair, which eliminates contact force errors while achieving highly repeatable measurements thanks to the nanometer-level precision of the sensor.

[0025] Meanwhile, a quick-assembly and sturdy tooling bracket was designed to ensure the applicability and high efficiency of the method on the assembly site. Ultimately, this invention integrates the advantages of non-contact measurement and rapid on-site assembly and adjustment, achieving an optimal balance in terms of cost, accuracy, efficiency, and reliability.

[0026] Figure 2 A schematic diagram of a device 2000 for detecting the straightness of an ultra-precision hydrostatic guide rail according to an embodiment of the present invention is shown. Figure 3 A schematic diagram of the structure of a detection device 2000 according to another embodiment of the present invention is shown. Figure 4 A schematic diagram of the spatial positions of the calibration element 2100 and the calibration element holder 2300 according to an embodiment of the present invention is shown. Figure 5 A schematic diagram of the spatial positions of displacement sensor 2200 and sensor 2400 according to an embodiment of the present invention is shown. Figure 6 A schematic diagram of the spatial positions of the calibration element 2100 and the calibration element holder 2300 according to another embodiment of the present invention is shown. Figure 7 A schematic diagram of the spatial positions of displacement sensor 2200 and sensor 2400 according to another embodiment of the present invention is shown. Figure 8 A schematic diagram of the structure of a calibration element 2100 according to an embodiment of the present invention is shown. Figure 9 A schematic diagram of a method 3000 for detecting the straightness of an ultra-precision hydrostatic guide rail according to an embodiment of the present invention is shown.

[0027] like Figures 2 to 8 As shown, the detection device 2000 includes a calibration component 2100, a displacement sensor 2200, a calibration component holder 2300, a sensor holder 2400, and a data processor 2500.

[0028] The calibration surface of the calibration component 2100 is configured to be arranged perpendicularly to the first or second guide surface in the plane to be measured of the hydrostatic guide rail, in order to accommodate measurements in different directions, wherein the first and second guide surfaces are perpendicular to each other.

[0029] In some embodiments, the plane to be measured on the hydrostatic guide rail includes its horizontal and vertical planes. Figure 1Taking the X-axis hydrostatic guide 1100 of the machine tool 1000 as an example: the upper surface of the slide plate 1110 included therein is the horizontal plane of the X-axis hydrostatic guide 1100, and the side perpendicular to the horizontal plane is the vertical plane of the X-axis hydrostatic guide 1100.

[0030] The displacement sensor 2200 is fixed to the slide plate of the hydrostatic guide rail, and its probe is perpendicular to the calibration surface. This allows the displacement sensor 2200 and the calibration surface to form a non-contact measurement pair during the movement of the slide plate, and the displacement data is obtained by sensing the change in the distance between the sensor and the calibration surface.

[0031] Continuing the example above, during measurement, it is necessary to establish the perpendicular relationship between the probe of the displacement sensor 2200 and the calibration surface. Therefore, when measuring the straightness of a horizontal plane, as... Figure 2 As shown, the calibration surface of calibration component 2100 needs to be adjusted to be perpendicular to the horizontal plane (i.e., the calibration surface is in a vertical state, such as...). Figure 4 At this time, the probe direction of the displacement sensor 2200 is parallel to the horizontal plane (i.e., the probe is in a parallel state, such as...). Figure 5 When measuring the straightness of a vertical plane, such as... Figure 3 As shown, the calibration surface of the calibration component 2100 needs to be adjusted to be perpendicular to the vertical plane (at this time, the calibration surface is in a horizontal state and parallel to the upper surface of the slide plate 1110, as shown). Figure 6 At this time, the probe direction of the displacement sensor 2200 is perpendicular to the horizontal plane (i.e., the probe is in a vertical state, as shown in Figure 2200). Figure 7 ).

[0032] The calibration component 2100 is fixed by the calibration component holder 2300. During installation, by adjusting the posture of the calibration component holder 2300 or the calibration component 2100 itself, its calibration surface can be precisely set to be parallel to the first guide rail surface or the second guide rail surface, thereby achieving adaptive measurement of the straightness of the guide rail in different directions.

[0033] In some embodiments, the calibration component holder 2300 comprises a first base 2310 and a first support 2320 forming a rigid support module. The first base 2310 is rigidly connected to the machine tool bed 1300 by bolts, establishing the installation reference; the first support 2320 serves as the installation interface, fixing the calibration component 2100. This modular design not only achieves stable installation of the calibration component, but also provides a structural basis for the initial adjustment and precise positioning of the vertical relationship between the calibration surface and the sensor probe through the cooperation of the first base 2310 and the first support 2320.

[0034] In some embodiments, such as Figure 8 As shown, standard part 2100 is used to provide a high-precision reference plane, which includes stone foot 2110, stone foot seat 2120 and shim 2130.

[0035] The Stonefoot 2110 can be polished to an extremely high surface finish (down to the nanometer level), making its surface roughness far below the measurement accuracy requirements. This provides the displacement sensor 2200 with a near-ideal optical reflective surface. The smooth surface can generate a stable, high signal-to-noise ratio measurement signal, avoiding signal scattering and measurement fluctuations caused by surface roughness, which is a key prerequisite for achieving nanometer-level repeatability accuracy.

[0036] The working surface of the stone foot 2110 is the calibration surface. The stone foot 2110 is finally installed and precisely positioned on the calibration component holder 2300 through the stone foot base 2120.

[0037] Its installation logic is as follows: First, precisely fix the stone foot base 2120 to the calibration piece holder 2300 to establish the reference. Subsequently, the stone foot 2110 is installed and positioned on the stone foot base 2120.

[0038] This hierarchical installation method of "calibration component holder 2300 → stone foot seat 2120 → stone foot 2110" provides a structural basis for accurately controlling the spatial orientation of the working surface of the stone foot 2110 (such as the parallelism with the guide rail surface to be measured), which is the key to achieving high-precision measurement.

[0039] The shim 2130 serves as a fine-tuning mechanism and is movably positioned at the mounting interface formed by the stone foot 2110 and the stone foot seat 2120. By changing the number or position of the shims 2130, the mounting posture of the stone foot 2110 can be finely adjusted, thereby ensuring that the calibration surface and the displacement sensor 2200 establish a precise spatial relationship.

[0040] The displacement sensor 2200 is fixed to the slide plate 1110 by the sensor mounting bracket 2400. The mounting bracket 2400 is configured to support and accurately position the displacement sensor 2200, so that its probe maintains a preset vertical alignment with the calibration surface of the calibration component 2100 throughout the entire movement of the slide plate 1110.

[0041] In some embodiments, the displacement sensor 2200 is a spectral confocal displacement sensor. Choosing a spectral confocal displacement sensor enables "nanoscale" non-contact measurement, fundamentally solving the scratch risk and contact force error problems associated with contact measurements; ensuring high repeatability and reliability of measurement results, making the detection data an authoritative basis for assembly and debugging; enhancing the field applicability of the entire detection system, overcoming the weakness of equipment such as laser interferometers in terms of stringent environmental requirements, and meeting the needs of rapid detection at "machine tool assembly sites".

[0042] The sensor mounting bracket 2400 consists of a second base 2410 and a second support 2420. The second base 2410 serves as a rigid interface fixed to the slide plate; the second support 2420 acts as a precision displacement mechanism mounted on the base, supporting the displacement sensor 2200 through its movement and precisely adjusting the distance between its probe and the calibration surface. This adjustable design ensures that the displacement sensor 2200 is always at the optimal working distance, which is crucial for ensuring stable measurement signals and reliable results.

[0043] In some embodiments, to balance measurement safety and data accuracy, the distance between the probe of the displacement sensor 2200 and the calibration surface is set to 6 mm to 10 mm. This distance setting is sufficient to achieve completely non-contact measurement, eliminating the risk of collision with the precision calibration surface; on the other hand, it ensures that the sensor operates within its calibrated high-precision measurement range. Particularly preferred, a distance of approximately 8 mm has been verified to provide the most stable and reliable displacement data throughout the entire measurement stroke.

[0044] The data processor 2500 and displacement sensor 2200 are electrically connected, forming a closed-loop "acquisition-processing" system. Its core value lies in its built-in dedicated error compensation program. In practice, the calibration surface of the stone foot 2110 is difficult to achieve absolute parallelism with the theoretical guide rail through mechanical leveling; even slight installation tilt can directly contaminate the measurement results. Therefore, this invention uses a pre-installed, MATLAB-based intelligent algorithm to mathematically solve the acquired displacement data, effectively eliminating the linear error component caused by the stone foot installation tilt angle, thereby minimizing systematic errors and ensuring the authenticity and reliability of the final output straightness result.

[0045] The detection device 2000 provided by the present invention uses a displacement sensor 2200 and a calibration component 2100 to form a non-contact measurement pair. While eliminating contact force error, it achieves high repeatability measurement with the nanometer-level precision of the sensor.

[0046] Meanwhile, a quick-assembly and sturdy tooling bracket was designed to ensure the applicability and high efficiency of the device 2000 on the assembly site. Ultimately, this invention integrates the advantages of non-contact measurement and rapid on-site assembly and adjustment, achieving an optimal balance in terms of cost, accuracy, efficiency, and reliability.

[0047] Figure 9 A schematic flowchart of a method 3000 for detecting the straightness of an ultra-precision hydrostatic guide rail according to an embodiment of the present invention is shown. The method 3000 is implemented using the aforementioned detection device 2000.

[0048] like Figure 9As shown, method 3000 begins with step 3100, in which the calibration component 2100 and displacement sensor 2200 of the detection device 200 are installed accordingly based on the determined hydrostatic guide rail test plane.

[0049] To ensure a precise spatial correspondence between the measurement reference and the object being measured, the installation process must follow a clear logic and set of steps. Specifically, this installation process can be systematically described as follows: 1. Define the measurement object and benchmark.

[0050] The first step is to determine the plane to be tested: that is, to clarify whether the target of this test is the horizontal plane (upper generatrix) or the vertical plane (side generatrix) of the hydrostatic guide rail. This determination is the basis for all subsequent installation operations.

[0051] 2. Configure calibration reference – installation of calibration component 2100.

[0052] According to the orientation of the plane to be measured, the calibration piece 2100 is mounted on the stationary machine tool bed 1300 via its calibration piece holder 2300. Specifically, the orientation of the calibration piece 2100 is adjusted so that its calibration surface is strictly perpendicular to the selected plane to be measured.

[0053] If measuring a horizontal plane, the calibration plane should be adjusted to be vertical.

[0054] If measuring a vertical plane, the calibration plane should be adjusted to a horizontal orientation.

[0055] 3. Configure the measurement unit – installation of displacement sensor 2200.

[0056] The displacement sensor 2200 is mounted on the slide plate of the hydrostatic guide rail via the sensor mounting bracket 2400. Specifically, the position and orientation of the sensor are adjusted to ensure that its probe remains vertically aligned with the calibration surface of the installed calibration component 2100 throughout the entire movement, and maintains an optimal working distance of approximately 8 mm.

[0057] The final installation resulted in a high-precision measurement system consisting of a static reference (calibrator 2100) and a moving probe (displacement sensor 2200). This "one moving, one static" corresponding installation relationship is the geometric basis for directly converting the straightness error of the hydrostatic guide rail into the spacing change that the displacement sensor 2200 can detect, and is the premise for the entire detection method to be valid.

[0058] It should be noted that when installing the testing device 2000, in order to reduce the impact of external factors such as environment and component abnormalities on the test results, preparatory work such as cleaning the hydrostatic guide rail and detecting component abnormalities is required. Specifically: Before installing the 2000 testing device, the following preparatory work must be performed to eliminate interference from environmental and component abnormalities on the measurement results: First, clean the reference surface to be tested: Use anhydrous ethanol and industrial non-woven fabric to thoroughly clean the surfaces of the slides of the X-axis hydrostatic guideway 1100 and Z-axis hydrostatic guideway 1200 of the machine tool, as well as the corresponding installation areas of the machine tool bed 1300, to ensure that there are no contaminants, oil stains or scratches on each measurement and installation reference surface.

[0059] Then, check the status of the tooling components: Conduct a comprehensive inspection of all components of the testing fixture to confirm that there is no structural damage or abnormal wear, and verify that all fastening bolts are in the specified pre-tightened state and that there is no looseness.

[0060] Finally, verify the functionality of the measuring instruments: Confirm that the displacement sensor 2200 and its associated display and control instruments are functioning correctly. Perform power-on warm-up, zero-point calibration, and signal stability testing on the sensor to ensure it is in optimal working condition.

[0061] Subsequently, in step 3200, the hydrostatic guide rail is activated, causing the slide to drive the displacement sensor 2200 to perform at least three full-stroke reciprocating motions along the guide rail.

[0062] After the installation and calibration of the detection device 2000 are completed, the measurement execution phase of data acquisition begins. The core of this phase is to acquire reliable displacement data sufficient to reflect true accuracy through the specific motion pattern of the slide plate. Specifically, the hydraulic and drive system of the hydrostatic guide rail is activated, causing the slide plate to move the displacement sensor 2200 fixed to it. This simulates the actual working state of the guide rail and performs measurements during the motion.

[0063] "Full stroke" refers to the skateboard moving from one end of the guide rail to the other, covering its entire effective working stroke. This ensures that the straightness at any position along the entire length of the guide rail is sampled, with no blind spots in detection.

[0064] "Reciprocating motion" refers to one complete cycle of the slide moving from point A to point B and then back from point B to point A. This bidirectional motion can reveal the different error characteristics that may exist in the guide rail during forward and reverse operation.

[0065] "At least three times": This is a key design feature to ensure the statistical significance and repeatability of the measurement results.

[0066] Eliminating random errors: By taking multiple measurements, random errors caused by instantaneous environmental fluctuations (such as micro-vibrations) or small fluctuations in the measurement system itself can be averaged out.

[0067] Verifying repeatability: Good consistency among three or more repeated measurements is a strong verification of the repeatability of the guide rail movement and the stability of the measurement system. If the curve shape of each measurement is highly consistent, it proves that the data is reliable; if the difference is large, it suggests that there may be unstable factors.

[0068] Provide sufficient data: Provide a rich and reliable dataset for subsequent data processing and error compensation algorithms to ensure that the final straightness error curve is real, smooth and reliable.

[0069] Subsequently, in step 3300, during the full-stroke reciprocating motion, the displacement sensor 2200 collects the change in the distance between itself and the calibration surface as displacement data.

[0070] During the skateboard's full-stroke reciprocating motion, the displacement sensor 2200 is activated and enters continuous operation, performing the following precise data acquisition tasks: 1. Real-time, synchronous dynamic measurement This process is not a static, single-point measurement, but a dynamic data stream capture process synchronized with the skateboard movement in real time. The displacement sensor 2200 continuously measures the instantaneous distance between its probe and the calibration surface of the calibration piece 2100 at every moment of the skateboard movement, using an extremely high sampling frequency (typically up to several kilohertz).

[0071] 2. Convert geometric errors into electrical signals This minute change in spacing directly reflects the spatial positional deviation of the hydrostatic guide rail along its trajectory. Ideally, if the guide rail is perfectly straight and the calibration surface is perfectly flat, this spacing value should remain constant. Any actual error in the straightness of the guide rail will cause a slight vertical or horizontal shift in the slide plate, which will be captured by the sensor in real time as fluctuations in the spacing.

[0072] Therefore, the displacement sensor 2200 is essentially a high-precision converter that transforms complex spatial geometric errors that are difficult to observe directly into one-dimensional displacement electrical signals that can be precisely quantified and recorded.

[0073] 3. Form a complete error data image By continuously collecting data throughout the entire travel distance, a complete sequence of displacement data, corresponding one-to-one with each travel position, is ultimately obtained. This data sequence constitutes the "displacement data," which completely maps the deviation between the actual trajectory of the guide rail and the ideal straight line in the measurement direction.

[0074] Finally, in step 3400, the displacement data is processed by the data processor 2500 to obtain the straightness of the plane measured by the hydrostatic guide rail.

[0075] After the displacement sensor 2200 completes data acquisition, the data processor 2500, acting as the "brain" of the system, begins to execute the following key processes to convert the raw displacement data into intuitive and accurate straightness evaluation results: 1. Data reception and preprocessing Data Interface: The data processor 2500 receives the raw displacement data stream from the displacement sensor 2200 via wired or wireless means. The data processor 2500 first precisely correlates the displacement data with the travel position of the slide plate. Subsequently, a digital filter (such as a low-pass filter) may be applied to smooth the data, suppress interference from high-frequency electronic noise or transient environmental disturbances, and retain the low-frequency error signal representing the true shape of the guide rail.

[0076] 2. Core Algorithm Processing and Error Compensation The data processor 2500 calls an embedded, dedicated algorithm written on platforms such as MATLAB. This algorithm incorporates a mathematical model of the stone foot installation tilt, which can intelligently identify and separate the linear systematic error components introduced by the installation deviation of the calibration component 2100 from the raw displacement data.

[0077] After this step, the resulting data minimizes the impact of imperfect installation, allowing it to more accurately reflect the precision of the hydrostatic guide rail itself.

[0078] 3. Straightness Calculation and Result Generation The processed data is used to calculate straightness. Typically, the least squares method is used to fit an "optimal reference line". Then, the sum of the absolute values ​​of the maximum positive and maximum negative deviations of all data points relative to this reference line is calculated; this value is the straightness error of the guide rail.

[0079] The data processor 2500 will eventually generate a detailed inspection report. This report not only includes the final straightness error value, but also usually includes a straightness error graph. This graph visually shows where the guide rail bulges and dents along its entire length, providing precise and quantitative guidance for subsequent assembly and debugging.

[0080] The method provided by this invention integrates the advantages of non-contact nanometer measurement, field applicability, and intelligent error compensation, achieving a technological breakthrough. It employs a combination of a displacement sensor 2200 and a calibration component 2100 to perform measurements with nanometer-level precision, completely eliminating the force deformation error and scratch risk inherent in contact measurements. The dedicated quick-assembly and disassembly fixture structure is robust, significantly improving testing efficiency and repeatability, and perfectly adapting to assembly site environments. The built-in intelligent algorithm automatically compensates for installation errors, ensuring reliable and accurate results. This method achieves an optimal balance in terms of accuracy, efficiency, reliability, and cost-effectiveness, effectively solving the industry challenge of ultra-precision guide rail straightness testing.

[0081] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0082] As used herein, unless otherwise specified, the use of ordinal numbers such as “first,” “second,” “third,” etc., to describe ordinary objects merely indicates different instances of similar objects and is not intended to imply that the objects being described must have a given order in time, space, ordering, or any other manner.

[0083] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and alterations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims.

Claims

1. A device for detecting the straightness of an ultra-precision hydrostatic guide rail, the hydrostatic guide rail comprising a guide assembly and a motion assembly, the motion assembly comprising at least a sliding plate, which is suspended by a hydrostatic oil film and adapted to reciprocate linearly along the guide assembly, the detection device comprising: The calibration component has its calibration surface configured to be arranged perpendicularly to the first or second guide surface in the plane to be measured of the hydrostatic guide rail, in order to adapt to measurements in different directions, wherein the first and second guide surfaces are perpendicular to each other. A displacement sensor is fixed to the slide plate, with its probe perpendicular to the calibration surface. This allows the displacement sensor and the calibration surface to form a non-contact measurement pair during the movement of the slide plate, and displacement data is obtained by sensing the change in the distance between the sensor and the calibration surface.

2. The apparatus of claim 1, wherein, Also includes: The calibration piece holder includes a first base and a first support base; The first base is bolted to the machine tool bed that supports the hydrostatic guide rail; The first support is fixed on the first base and is used to support the calibration component, so that its calibration surface is perpendicular to the probe of the displacement sensor.

3. The apparatus of claim 1, wherein, Also includes: The sensor mounting bracket includes a second base and a second support bracket; The second base is bolted to the slide plate; The second support frame is movably mounted on the second base to support the displacement sensor and to adjust the distance between the probe of the displacement sensor and the calibration surface of the calibration piece.

4. The apparatus of claim 3, wherein, The distance between the probe of the displacement sensor and the calibration surface of the calibration component is 6mm to 10mm.

5. The apparatus of claim 2, wherein, The standard components include: Stone feet and stone foot base; The working surface of the stone foot constitutes the calibration surface, and the stone foot is mounted and positioned on the calibration fixture via a stone foot seat.

6. The apparatus of claim 5, wherein, The standard components also include: A shim, movably disposed between the stone foot and the stone foot seat, is used to adjust the installation position of the stone foot.

7. The apparatus of claim 1, wherein, The displacement sensor is a spectral confocal displacement sensor.

8. The apparatus of claim 1, wherein, Also includes: The data processor, electrically connected to the displacement sensor, is used to receive the displacement data collected by the displacement sensor and process the displacement data to obtain the straightness of the plane measured by the hydrostatic guide rail.

9. The apparatus of claim 8, wherein, The data processor is equipped with an error compensation program, which is an algorithm based on MATLAB, used to eliminate errors caused by the tilt of the calibration component during installation.

10. A method for detecting the straightness of ultra-precision hydrostatic guideways, implemented using the detection device as described in any one of claims 1 to 9, the method comprising: Based on the determined test plane of the hydrostatic guide rail, the calibration components and displacement sensors of the detection device are installed accordingly; Start the hydrostatic guide rail, so that the slide plate drives the displacement sensor to perform at least three full-stroke reciprocating motions along the guide rail; During the full-stroke reciprocating motion, the displacement sensor is used to collect the change in the distance between itself and the calibration surface, which is used as displacement data. The displacement data is processed using a data processor to obtain the straightness of the plane measured by the hydrostatic guide rail.

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