Gantry type double-station ultra-precision grinding machine tool and grinding method

Abstract

The invention discloses a gantry type double-station ultra-precision grinding machine tool and a grinding method, and relates to the technical field of ultra-precision machining. The problems that an existing ultra-precision machine tool is low in machining efficiency and machining precision and errors are caused by repeated clamping are solved. A machine tool body is a gantry type machine tool body, the gantry type machine tool body comprises a machine tool body, a machine tool cross beam and two machine tool stand columns, the machine tool body is horizontally arranged in the Y-axis direction, and the machine tool cross beam is horizontally arranged over the machine tool body in the X-axis direction; two machine tool stand columns are vertically and symmetrically arranged on the front side and the rear side below the machine tool beam in the Z-axis direction, the lower ends of the two machine tool stand columns are connected with the upper surface of the machine tool body, and the upper ends of the two machine tool stand columns are connected with the lower surface of the machine tool beam. The system is used for achieving station assembly line type machining or independent machining in a serial mode of the ultra-precision machine tool, and achieving multiple machining modes such as double-station simultaneous machining in a parallel mode.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-precision machining, and in particular to a gantry-type double-station ultra-precision grinding machine tool and a grinding method. Background Art

[0002] Ultra-precision machine tools are mainly used for machining accuracy less than 10μm, and the minimum motion resolution can reach 1nm. Using ultra-precision machine tools for cutting, grinding, milling and other processing can achieve nanometer-level surface roughness. Ultra-precision machine tools are mainly used in ultra-precision machining fields such as optics, semiconductors, national defense, medical treatment, ophthalmology, consumer electronics, and micro-nano engineering, and play an irreplaceable role in the nano-level machining field of manufacturing. In order to improve the level of my country's manufacturing industry, it is of great significance to develop independently developed domestic ultra-precision machine tools.

[0003] In the field of ultra-precision machine tools at home and abroad, for example, the Moore Nanotech series of ultra-precision machine tools in the United States use low-frequency air isolation damping systems and fully constrained oil hydrostatic guides. The Precitech Nanoform series of ultra-precision machine tools in the United States have symmetrical linear motor installations and liquid-cooled hydrostatic oil bearing guides. Japan's Toshiba UVM series nano-machining centers are equipped with ultra-precision air hydrostatic bearing spindles and liquid hydrostatic guides with cooling systems. In the field of ultra-precision machine tools in China, such as the UPL series of ultra-precision machine tools of Xinghai Optoelectronics and the DJC series of ultra-precision machine tools of Hypreson, all use liquid hydrostatic guides and air hydrostatic spindles. The above ultra-precision machine tools all have common characteristics: 1. Horizontal processing; 2. Liquid hydrostatic guides and air hydrostatic spindles; 3. A machine tool has only one processing station and one set of CNC systems.

[0004] Machining efficiency and machining accuracy have always been the primary factors in the machining process. The dual-station ultra-precision machine tool has two sets of CNC systems, which can realize dual-station simultaneous machining, that is, parallel mode. In this mode, the machining efficiency is higher than that of a single-station machining, and different machining processes can be realized. It is also possible to perform sequential processing in serial mode, which can not only realize post-processing in-situ detection, compensation processing, and iterative processing to improve the surface accuracy of the machined parts, but also realize rapid switching of processes such as first grinding and cutting processing and then polishing processing to achieve high-precision in-situ processing, avoiding errors caused by repeated clamping.

[0005] Based on the above technical background analysis, a new form of grinding machine tools and processing concepts are urgently needed to improve the level of ultra-precision machining. This double-station ultra-precision machine tool can further improve the machining efficiency and machining accuracy, greatly reduce the manufacturing cost, and has epoch-making significance for traditional ultra-precision machining methods. Summary of the invention

[0006] The purpose of the present invention is to solve the problems of low machining efficiency and machining accuracy of existing ultra-precision machine tools, as well as errors caused by repeated clamping, and further to provide a gantry-type double-station ultra-precision grinding machine tool and a grinding method.

[0007] The technical solution of the present invention is: A gantry-type double-station ultra-precision grinding machine tool, comprising a machine tool body, a Y-axis assembly, two X-axis assemblies, two Z-axis assemblies, two B-axis assemblies, two processing tools and two detection tools; the machine tool body is a gantry-type machine tool body, which comprises a machine tool bed, a machine tool crossbeam and two machine tool columns, the machine tool bed is horizontally arranged along the Y-axis direction, the machine tool crossbeam is horizontally arranged directly above the machine tool bed along the X-axis direction, and two machine tool columns are vertically symmetrically arranged on both sides of the front and rear sides below the machine tool crossbeam along the Z-axis direction. The lower ends of the two machine tool columns are fixedly connected to the upper surface of the machine tool bed, and the upper ends of the two machine tool columns are fixedly connected to the lower surface of the machine tool crossbeam; the Y-axis assembly includes a Y-axis linear drive mechanism, a Y1-axis slide and a Y2-axis slide, the Y-axis linear drive mechanism is installed on the upper part of the machine tool bed along the Y-axis direction, and the Y1-axis slide and the Y2-axis slide are respectively installed at the two moving ends of the Y-axis linear drive mechanism; the B-axis assembly includes a B1-axis rotation drive mechanism, a B1 turntable, a B2-axis rotation drive mechanism and a B2 turntable, the B1-axis rotation drive mechanism and the B2-axis rotation drive mechanism The driving mechanisms are respectively installed on the Y1-axis slide and the Y2-axis slide. The B1 turntable and the B2 turntable are respectively arranged above the B1-axis rotation driving mechanism and the B2-axis rotation driving mechanism and connected to their rotating shafts. The X-axis assembly includes the X1-axis linear driving mechanism, the X1-axis slide, the X2-axis linear driving mechanism and the X2-axis slide. The X1-axis linear driving mechanism and the X2-axis linear driving mechanism are respectively installed on the left and right sides of the machine tool crossbeam along the X-axis direction. The X1-axis slide and the X2-axis slide are respectively installed on the X1-axis linear driving mechanism and the X2-axis linear driving mechanism. The Z-axis assembly comprises a Z1-axis linear drive mechanism, a Z1-axis slide, a Z2-axis linear drive mechanism and a Z2-axis slide. The Z1-axis linear drive mechanism and the Z2-axis linear drive mechanism are respectively symmetrically mounted on the X1-axis slide and the X2-axis slide along the Z-axis direction. The Z1-axis slide and the Z2-axis slide are respectively mounted on the moving ends of the Z1-axis linear drive mechanism and the Z2-axis linear drive mechanism. A processing tool and a detection tool are mounted on the Z1-axis slide, and a processing tool and a detection tool are mounted on the Z2-axis slide.

[0008] Furthermore, the Y-axis linear drive mechanism includes a Y-axis base, a Y-axis guide rail, a Y1-axis linear motor and a Y2-axis linear motor. The Y-axis base is installed on the upper part of the machine tool bed, the Y-axis guide rail is installed on the Y-axis base along the Y-axis direction, the Y1-axis slide and the Y2-axis slide are both slidably connected to the Y-axis guide rail, and the Y1-axis slide and the Y2-axis slide are respectively connected to the Y-axis guide rail through the Y1-axis linear motor and the Y2-axis linear motor.

[0009] Furthermore, the X1-axis linear drive mechanism includes an X1-axis base, an X1-axis linear motor and an X1-axis guide rail. The X1-axis base is installed on one side of the machine tool crossbeam, and the X1-axis guide rail is installed on the X1-axis base along the X-axis direction. The X1-axis slide is slidably connected to the X1-axis guide rail, and the X1-axis slide is connected to the X1-axis guide rail through the X1-axis linear motor; the X2-axis linear drive mechanism includes an X2-axis base, an X2-axis linear motor and an X2-axis guide rail. The X2-axis base is installed on the other side of the machine tool crossbeam, and the X2-axis guide rail is installed on the X2-axis base along the X-axis direction. The X2-axis slide is slidably connected to the X2-axis guide rail, and the X2-axis slide is connected to the X2-axis guide rail through the X2-axis linear motor.

[0010] Furthermore, the Z1-axis linear drive mechanism includes a Z1-axis base, a Z1-axis motor, and a Z1-axis ball screw linear guide. The Z1-axis base is installed on the X1-axis slide. The Z1-axis ball screw linear guide is provided on the outer side of the Z1-axis base along the Z-axis direction. The Z1-axis motor is installed on the upper end of the Z1-axis base. The rotating shaft of the Z1-axis motor is connected to the upper end of the screw in the Z1-axis ball screw linear guide. The slider in the Z1-axis ball screw linear guide is fixed to the Z1-axis slide. Connection; The Z2-axis linear drive mechanism includes a Z2-axis base, a Z2-axis motor, and a Z2-axis ball screw linear guide. The Z2-axis base is installed on the X2-axis slide. A Z2-axis ball screw linear guide is provided on the outer side of the Z2-axis base along the Z-axis direction. A Z2-axis motor is installed on the upper end of the Z2-axis base. The rotating shaft of the Z2-axis motor is connected to the upper end of the screw in the Z2-axis ball screw linear guide, and the slider in the Z2-axis ball screw linear guide is fixedly connected to the Z2-axis slide.

[0011] Furthermore, the Z-axis assembly also includes two Z1-axis cylinder assemblies and two Z2-axis cylinder assemblies; the two Z1-axis cylinder assemblies are symmetrically arranged on both sides of the Z1-axis base, each Z1-axis cylinder assembly includes a Z1-axis cylinder body, a Z1-axis cylinder connecting base and a Z1-axis cylinder L-shaped connecting top plate, the lower end of the cylinder body of the Z1-axis cylinder body is connected to the Z1-axis cylinder connecting base, the Z1-axis cylinder connecting base is installed on the lower side of the Z1-axis slide, the piston rod end of the Z1-axis cylinder body is connected to the Z1-axis cylinder L-shaped connecting top plate, and the Z1-axis cylinder L-shaped connecting The connecting top plate is installed on the upper side of the Z1-axis base; the two Z2-axis cylinder assemblies are symmetrically arranged on both sides of the Z2-axis base, each Z2-axis cylinder assembly includes a Z2-axis cylinder body, a Z2-axis cylinder connecting base and a Z2-axis cylinder L-shaped connecting top plate, the lower end of the cylinder body of the Z2-axis cylinder body is connected to the Z2-axis cylinder connecting base, the Z2-axis cylinder connecting base is installed on the lower side of the Z2-axis slide, the piston rod end of the Z2-axis cylinder body is connected to the Z2-axis cylinder L-shaped connecting top plate, and the Z2-axis cylinder L-shaped connecting top plate is installed on the upper side of the Z2-axis base.

[0012] Furthermore, the Y-axis guide rail, the X1-axis guide rail and the X2-axis guide rail are all liquid hydrostatic guide rails; the B1-axis rotation drive mechanism and the B2-axis rotation drive mechanism are both liquid-floating hydrostatic turntables; and the machine tool bed is a granite bed.

[0013] Furthermore, it also includes multiple protective skins; one end of the Y1-axis slide is connected to one end of the Y2-axis slide with a protective skin, the other end of the Y1-axis slide is connected to one end of the Y-axis base with a protective skin, and the other end of the Y2-axis slide is connected to the other end of the Y-axis base with a protective skin; one end of the X1-axis slide is connected to one end of the X1-axis base with a protective skin, and the other end of the X1-axis slide is connected to the other end of the X1-axis base with a protective skin; one end of the X2-axis slide is connected to one end of the X2-axis base with a protective skin, and the other end of the X2-axis slide is connected to the other end of the X2-axis base with a protective skin; one end of the Z1-axis slide is connected to one end of the Z1-axis base with a protective skin, and the other end of the Z1-axis slide is connected to the other end of the Z1-axis base with a protective skin; one end of the Z2-axis slide is connected to one end of the Z2-axis base with a protective skin, and the other end of the Z2-axis slide is connected to the other end of the Z2-axis base with a protective skin.

[0014] The present invention also provides a grinding method, which uses a gantry-type double-station ultra-precision grinding machine tool to grind a sapphire free-form surface optical element, and comprises the following steps: Step 1: Grinding of sapphire free-form optical elements: A deterministic compensating grinding process for the surface error of a sapphire free-form surface optical element is performed on station one of a grinding machine tool, the sapphire free-form surface optical element is mounted on a B1 turntable, and the surface error of the sapphire free-form surface optical element is measured in situ using a detection tool on station one to obtain original measurement information, the original measurement information including grinding lines (medium frequency) and surface roughness (high frequency), and then the error separation is performed on the measured original measurement information to obtain discrete measurement information; a grinding wheel error model is established using the discrete measurement information to generate a grinding wheel trajectory for compensation processing, and finally the grinding process of the sapphire free-form surface optical element is completed; Step 2: Polishing of sapphire free-form optical elements: The Y1-axis slide is driven by the Y-axis linear drive mechanism, and the B1-axis rotation drive mechanism, the B1 turntable and the sapphire free-form surface optical element on the B1 turntable on the Y1-axis slide are driven to move from the station 1 of the grinding machine tool to the station 2 of the grinding machine tool along the Y-axis guide rail to perform polishing after grinding; Step 3: Inspection of sapphire free-form optical components: The detection tool on station two is used to measure the medium and high frequency errors on the surface of the ground and polished sapphire free-form optical element to check whether the workpiece meets the processing requirements.

[0015] Furthermore, the specific process of performing error separation on the original measurement information obtained by measurement to obtain discrete measurement information is as follows: The error separation is performed using a wavelet decomposition method, comprising the following steps: Wavelet decomposition is based on wavelet transform and uses wavelet basis functions to decompose the original measurement information at different scales. , the wavelet decomposition is calculated by formula (1): (1) In formula (1), L is the scale range, is the decomposed function, is the stretch factor, is the translation factor, is the time from the start of collection to the end of collection, is the time scale, is the function that needs to be decomposed, is the wavelet function, yes The basis wavelet function, yes The average value of the basis wavelet function Calculated by formula (2): , , (2) In formula (2), the stretch factor and translation factor Control the stretching and translation of the base wavelet to form wavelet bases of different scales; Since the measured data set consists of discrete points, the stretch factor and translation factor Discretization is performed, and the discrete formula is calculated as formula (3): , , , , (3) In formula (3), is the stretch factor constant, is the translation factor constant, is the factor degree, is a proportional plural, is the set of integers; Basis wavelet function Discretize, discrete wavelet function Calculated by formula (4): (4) Discrete wavelet decomposition Calculated by formula (5): (5) The discrete orthogonal wavelet Daubechies is used to separate the contour error of the original measurement information, and the scaling function To approximate the measured signal, the scaling function is calculated by formula (6): (6) final, The wavelet decomposition calculation formula is as follows: (7) In formula (7): and The scaling functions are and discrete wavelet function The coefficient of Combining the two expressions in formula (7), we can get , and then the formula (7) Substituting into formula (5), we get the discrete wavelet decomposition of the discrete measurement signal: , discrete wavelet decomposition Used to process raw measurement information and convert continuous raw measurement information into discrete measurement information.

[0016] Furthermore, the specific process of using the discrete measurement information to establish a grinding wheel error model, generate a grinding wheel trajectory for compensation processing, and finally complete the grinding process of the sapphire free-form surface optical element is as follows: Any point on the grinding path The surface normal vector Calculated by formula (8): (8) In formula (8): and The equations of the double-tapered free-form surface are Axis and The partial derivatives of the axes, and Yes The second-order derivative of , and In the Cartesian coordinate system , and The unit vector of the axis; Wheel center at each contact point on the grinding path Correction position Calculated by formula (9): (9) In formula (9): Corrected grinding wheel radius and grinding wheel waviness error In the normal vector direction, is a unit vector, is the radial deviation of the grinding wheel along the X direction; The contact point between the grinding wheel and the workpiece on the grinding path at any given moment is , and use the vector Indicates that the position of the grinding wheel abrasive grain is , Grinding wheel waviness error Grinding wheel angle The arc of the grinding wheel cross section Corresponding angle, grinding wheel angle Calculated by formula (10), the angle between the center of the grinding wheel, the line connecting the contact point and the z-axis is Calculated by formula (11): (10) (11) Radial deviation of grinding wheel along X direction By unit vector Represents the unit vector Calculated by formula (12): (12) At this point, all variables in formula (9) have been solved, so the corrected grinding wheel center position is calculated , in fact, the center of rotation The position of is used to generate the grinding wheel trajectory for contour error compensation. The corrected rotation center Position vector Indicates that vector Calculated by the grinding wheel error model shown in formula (13): (13) In formula (13): is the grinding wheel radius, is the radius of curvature of the free-form surface at the contact point; Then the above discrete wavelet decomposition is performed as described in formula (5) Substitute the obtained discrete measurement information into formula (13) to obtain the vector Specific value of Finally, a grinding wheel error model is established through in-situ measurement and error separation, and a grinding wheel trajectory for compensatory processing is generated. After the grinding wheel trajectory for compensatory processing is generated, a gantry-type double-station ultra-precision grinding machine is used to grind sapphire free-form surface optical elements. The grinding operation of sapphire free-form surface optical elements is achieved through the linkage of the X-axis assembly, Y-axis assembly, Z-axis assembly, B-axis assembly and processing tools on station one.

[0017] Compared with the prior art, the present invention has the following effects: 1. The gantry-type double-station ultra-precision grinding machine tool described in the present invention is a full-liquid hydrostatic shaft system gantry-type double-station ultra-precision grinding machine tool with switchable serial and parallel modes, which can realize the switching between parallel and serial modes. On the one hand, it can realize the station assembly line processing or independent processing in the serial mode; on the other hand, it can realize multiple processing modes such as dual-station simultaneous processing in the parallel mode.

[0018] 2. The gantry-type double-station ultra-precision grinding machine tool described in the present invention can realize station assembly line processing or independent processing in serial mode, and can also realize multiple processing modes such as dual-station simultaneous processing in parallel mode. The processing mode includes serial processing mode and parallel processing mode. In the serial processing mode, the serial processing mode can perform sequential processing, which can not only realize post-processing in-situ detection, compensation processing, and iterative processing to improve the surface accuracy of the workpiece, but also realize rapid switching of processes such as first grinding and cutting processing and then polishing processing to achieve high-precision in-situ processing, avoiding the errors caused by repeated clamping, and the above functions in the serial processing mode are all realized by station switching. The serial processing mode is: after the X1 axis, Y1 axis, Z1 axis, and B1 axis jointly process the workpiece, the Y-axis motor drives the Y1 axis slide, thereby driving the B1 axis and the workpiece on it to move along the Y-axis guide rail to the second station, and then the X2 axis, Y2 axis, Z2 axis, and B1 axis jointly perform subsequent processing on the workpiece to realize the serial process of workpiece processing. In the parallel processing mode, workstation 1 and workstation 2 are processed at the same time, the processing efficiency is higher than that of a single workstation, and different processing procedures can be realized. The parallel processing mode is: while the X1 axis, Y1 axis, Z1 axis, and B1 axis are processing the workpiece together, the X2 axis, Y2 axis, Z2 axis, and B2 axis are processing the workpiece together.

[0019] 3. Compared with the traditional gantry machine tool with a Z-axis added to one side of the beam, the gantry double-station ultra-precision grinding machine tool described in the present invention adds a Z1 axis and a Z2 axis on both sides of the machine tool beam, respectively, so that the weight on both sides of the machine tool beam is balanced, preventing the beam from torsional deformation causing the Z-axis to sway, resulting in reduced machining accuracy.

[0020] 4. Traditional machine tools cannot take into account both long travel and high precision, because after the length of the guide rail increases, its high precision requirement becomes more difficult to achieve. In the processing travel and precision of the gantry-type double-station ultra-precision grinding machine tool described in the present invention, the Y axis has both a long travel: 3000mm and high precision: straightness: 1μm. Therefore, the present invention can realize ultra-precision processing of large-caliber optical components and thinning, grinding and polishing of large-size semiconductor wafers.

[0021] 5. When the gantry-type double-station ultra-precision grinding machine tool described in the present invention is stationary and in working state, the weight borne by the machine tool beam on one side of the station (the sum of the weight of the X1-axis linear drive mechanism, the X1-axis slide, the Z1-axis linear drive mechanism, the Z1-axis slide, and the processing tools and detection tools mounted on the Z1-axis slide) and the weight borne on both sides of the station (the sum of the weight of the X2-axis linear drive mechanism, the X2-axis slide, the Z2-axis linear drive mechanism, the Z2-axis slide, and the processing tools and detection tools mounted on the Z2-axis slide) can be balanced with each other, thereby preventing the machine tool beam from torsional deformation, causing the Z-axis to deflect, resulting in reduced processing accuracy.

[0022] 6. The sapphire free-form surface optical element grinding processing method described in the present invention constructs an integrated ultra-precision integrated manufacturing technology process chain of "grinding + in-situ polishing + in-situ measurement" for sapphire free-form surface optical elements, which significantly improves processing efficiency and surface quality and reduces costs, and can realize the processing and manufacturing of large-aperture free-form surface optical elements, ultimately achieving an innovative breakthrough in my country's high-end manufacturing technology for free-form surface optical elements made of hard and brittle materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an axonometric view of the gantry-type double-station ultra-precision grinding machine tool described in the present invention; Figure 2 This is a front view of the gantry-type double-station ultra-precision grinding machine tool of the present invention; Figure 3 It is a side view of the gantry type double-station ultra-precision grinding machine tool of the present invention; Figure 4 It is a top view of the gantry type double-station ultra-precision grinding machine tool described in the present invention; Figure 5 It is a schematic diagram of the geometric structure generated by the contour error compensation path; Figure 6 It is a schematic diagram of the definition of contour error compensation path generation.

[0024] In the figure: 1. Machine bed; 2. Machine crossbeam; 3. Machine column; 4. Y-axis assembly; 5. X-axis assembly; 6. Z-axis assembly; 7. B-axis assembly; 8. Processing tool; 9. Inspection tool; 10. Y1-axis slide; 11. Y2-axis slide; 12. B1-axis rotation drive mechanism; 13. B2-axis rotation drive mechanism; 14. X1-axis slide; 15. X2-axis slide; 16. Z1-axis slide; 17. Z2-axis Slide; 18. Y-axis guide rail; 19. X1-axis guide rail; 20. X2-axis guide rail; 21. Z1-axis base; 22. Z1-axis motor; 23. Z2-axis base; 24. Z2-axis motor; 25. Z1-axis cylinder body; 26. Z1-axis cylinder connecting base; 27. Z1-axis cylinder L-shaped connecting top plate; 28. Z2-axis cylinder body; 29. ​​Z2-axis cylinder connecting base; 30. Z2-axis cylinder L-shaped connecting top plate. DETAILED DESCRIPTION

[0025] Specific implementation method 1: Combination Figures 1 to 4The present embodiment is described. A gantry-type double-station ultra-precision grinding machine tool of the present embodiment comprises a machine tool body, a Y-axis assembly 4, two X-axis assemblies 5, two Z-axis assemblies 6, two B-axis assemblies 7, two processing tools 8 and two detection tools 9; the machine tool body is a gantry-type machine tool body, which comprises a machine tool bed 1, a machine tool beam 2 and two machine tool columns 3. The machine tool bed 1 is horizontally arranged along the Y-axis direction, the machine tool beam 2 is horizontally arranged directly above the machine tool bed 1 along the X-axis direction, and two machine tool columns 3 are arranged vertically symmetrically on the front and rear sides below the machine tool beam 2 along the Z-axis direction. The lower ends of the two machine tool columns 3 are fixedly connected to the upper surface of the machine tool bed 1, and the upper ends of the two machine tool columns 3 are fixedly connected to the lower surface of the machine tool crossbeam 2; the Y-axis assembly 4 includes a Y-axis linear drive mechanism, a Y1-axis slide 10 and a Y2-axis slide 11, the Y-axis linear drive mechanism is installed on the upper part of the machine tool bed 1 along the Y-axis direction, and the Y1-axis slide 10 and the Y2-axis slide 11 are respectively installed at the two moving ends of the Y-axis linear drive mechanism; the B-axis assembly 7 includes a B1-axis rotation drive mechanism 12, a B1 turntable, a B2-axis rotation drive mechanism 13 and a B2 turntable, the B1-axis rotation drive mechanism 12 and the B2 The axis rotation drive mechanism 13 is respectively installed on the Y1 axis slide 10 and the Y2 axis slide 11, and the B1 turntable and the B2 turntable are respectively arranged above the B1 axis rotation drive mechanism 12 and the B2 axis rotation drive mechanism 13 and connected to their rotation shafts; the X-axis assembly 5 includes an X1 axis linear drive mechanism, an X1 axis slide 14, an X2 axis linear drive mechanism and an X2 axis slide 15, and the X1 axis linear drive mechanism and the X2 axis linear drive mechanism are respectively symmetrically installed on the left and right sides of the machine tool crossbeam 2 along the X-axis direction, and the X1 axis slide 14 and the X2 axis slide 15 are respectively installed on the X1 axis linear drive mechanism and the X2 axis linear drive mechanism. The moving end of the driving mechanism; the Z-axis assembly 6 includes a Z1-axis linear driving mechanism, a Z1-axis slide 16, a Z2-axis linear driving mechanism and a Z2-axis slide 17, the Z1-axis linear driving mechanism and the Z2-axis linear driving mechanism are respectively symmetrically installed on the X1-axis slide 14 and the X2-axis slide 15 along the Z-axis direction, the Z1-axis slide 16 and the Z2-axis slide 17 are respectively installed on the moving ends of the Z1-axis linear driving mechanism and the Z2-axis linear driving mechanism; a processing tool 8 and a detection tool 9 are installed on the Z1-axis slide 16, and a processing tool 8 and a detection tool 9 are installed on the Z2-axis slide 17.

[0026] In this embodiment, the processing stroke is: X axis 1300mm, Y axis 3000mm, Z axis 300mm, and the processing accuracy of the present invention is: Y axis straightness can reach 1μm. The processing tool 8 uses a grinding wheel, the grinding wheel speed is 4000~5000rpm, and the feed speed is 0.5~3mm / min.

[0027] Specific implementation method 2: Combination Figures 1 to 4This embodiment is described. The Y-axis linear drive mechanism of this embodiment includes a Y-axis base, a Y-axis guide rail 18, a Y1-axis linear motor and a Y2-axis linear motor. The Y-axis base is installed on the upper part of the machine tool bed 1. The Y-axis guide rail 18 is installed on the Y-axis base along the Y-axis direction. The Y1-axis slide 10 and the Y2-axis slide 11 are both slidably connected to the Y-axis guide rail 18. The Y1-axis slide 10 and the Y2-axis slide 11 are connected to the Y-axis guide rail 18 through the Y1-axis linear motor and the Y2-axis linear motor, respectively. With such a configuration, the Y-axis linear drive mechanism is used to achieve the displacement of the workpiece in the Y-axis direction. In the serial processing mode, the serial processing mode is realized by station switching, and in the switching process between station one and station two, a Y-axis guide rail 18 is shared. The serial processing mode can perform sequential processing, which can realize post-processing in-situ detection, compensation processing, and iterative processing to improve the surface accuracy of the workpiece, and can also realize rapid switching of processes such as first grinding and cutting processing and then polishing processing to achieve high-precision in-situ processing, avoiding errors caused by repeated clamping. Other components and connection relationships are the same as those of the first specific embodiment.

[0028] Specific implementation method three: Combination Figures 1 to 4 To illustrate this embodiment, the X1-axis linear drive mechanism of this embodiment includes an X1-axis base, an X1-axis linear motor and an X1-axis guide rail 19, the X1-axis base is installed on one side of the machine tool crossbeam 2, the X1-axis guide rail 19 is installed on the X1-axis base along the X-axis direction, the X1-axis slide 14 is slidably connected to the X1-axis guide rail 19, and the X1-axis slide 14 is connected to the X1-axis guide rail 19 through the X1-axis linear motor; the X2-axis linear drive mechanism includes an X2-axis base, an X2-axis linear motor and an X2-axis guide rail 20, the X2-axis base is installed on the other side of the machine tool crossbeam 2, the X2-axis guide rail 20 is installed on the X2-axis base along the X-axis direction, the X2-axis slide 15 is slidably connected to the X2-axis guide rail 20, and the X2-axis slide 15 is connected to the X2-axis guide rail 20 through the X2-axis linear motor. In this way, the X1-axis linear drive mechanism and the X2-axis linear drive mechanism are used to realize the displacement drive of the workpiece in the X1-axis and X2-axis directions, and both adopt the transmission mode driven by linear motors, which effectively improves the stability of the workpiece movement. Other components and connection relationships are the same as those of the specific implementation method one or two.

[0029] Specific implementation method four: Combination Figures 1 to 4The present embodiment is described. The Z1-axis linear drive mechanism of the present embodiment includes a Z1-axis base 21, a Z1-axis motor 22, and a Z1-axis ball screw linear guide. The Z1-axis base 21 is installed on the X1-axis slide 14. The Z1-axis ball screw linear guide is provided on the outer side of the Z1-axis base 21 along the Z-axis direction. The Z1-axis motor 22 is installed on the upper end of the Z1-axis base 21. The rotating shaft of the Z1-axis motor 22 is connected to the upper end of the screw in the Z1-axis ball screw linear guide. The slider in the Z1-axis ball screw linear guide is connected to the Z1-axis slide 16 is fixedly connected; the Z2 axis linear drive mechanism includes a Z2 axis base 23, a Z2 axis motor 24, and a Z2 axis ball screw linear guide. The Z2 axis base 23 is installed on the X2 axis slide 15. The Z2 axis ball screw linear guide is provided on the outer side of the Z2 axis base 23 along the Z axis direction. The Z2 axis motor 24 is installed on the upper end of the Z2 axis base 23. The rotating shaft of the Z2 axis motor 24 is connected to the upper end of the screw in the Z2 axis ball screw linear guide. The slider in the Z2 axis ball screw linear guide is fixedly connected to the Z2 axis slide 17. In this way, the Z1 axis linear drive mechanism and the Z2 axis linear drive mechanism adopt the transmission mode of the motor driving the screw, which effectively improves the stability of the workpiece movement. The other components and connection relationships are the same as those of the specific implementation mode one, two or three.

[0030] Specific implementation method five: Combination Figures 1 to 4To illustrate this embodiment, the Z-axis assembly 6 of this embodiment also includes two Z1-axis cylinder assemblies and two Z2-axis cylinder assemblies; the two Z1-axis cylinder assemblies are symmetrically arranged on both sides of the Z1-axis base 21, and each Z1-axis cylinder assembly includes a Z1-axis cylinder body 25, a Z1-axis cylinder connecting base 26 and a Z1-axis cylinder L-shaped connecting top plate 27, the lower end of the cylinder body of the Z1-axis cylinder body 25 is connected to the Z1-axis cylinder connecting base 26, and the Z1-axis cylinder connecting base 26 is installed on the lower side of the Z1-axis slide 16, the piston rod end of the Z1-axis cylinder body 25 is connected to the Z1-axis cylinder L-shaped connecting top plate 27, and the Z1-axis cylinder L-shaped The connecting top plate 27 is installed on the upper side of the Z1 axis base 21; the two Z2 axis cylinder assemblies are symmetrically arranged on both sides of the Z2 axis base 23, each Z2 axis cylinder assembly includes a Z2 axis cylinder body 28, a Z2 axis cylinder connecting base 29 and a Z2 axis cylinder L-shaped connecting top plate 30, the lower end of the cylinder body of the Z2 axis cylinder body 28 is connected to the Z2 axis cylinder connecting base 29, the Z2 axis cylinder connecting base 29 is installed on the lower side of the Z2 axis slide 17, the piston rod end of the Z2 axis cylinder body 28 is connected to the Z2 axis cylinder L-shaped connecting top plate 30, and the Z2 axis cylinder L-shaped connecting top plate 30 is installed on the upper side of the Z2 axis base 23. In this way, the Z1 axis cylinder assembly can balance the weight of the Z1 axis slide 16 and the processing tools 8 and the detection tools 9 installed thereon, so that the Z1 axis runs more smoothly and can prevent the Z1 axis from impacting and colliding when it stops. The Z2 axis cylinder assembly can balance the weight of the Z2 axis slide 17 and the processing tool 8 and the detection tool 9 mounted thereon, making the Z2 axis run more smoothly and preventing the Z2 axis from impacting and colliding when it stops. Other components and connection relationships are the same as those of the first, second, third or fourth embodiments.

[0031] Specific implementation method six: Combination Figures 1 to 4 To explain this embodiment, the Y-axis guide rail 18, X1-axis guide rail 19 and X2-axis guide rail 20 of this embodiment are all liquid hydrostatic guide rails, the B1-axis rotation drive mechanism 12 and the B2-axis rotation drive mechanism 13 are both liquid-floating hydrostatic turntables, and the machine tool bed 1 is a granite bed. Such an arrangement effectively improves the processing accuracy of the workpiece. Other components and connection relationships are the same as those of the specific embodiments one, two, three, four or five.

[0032] Specific implementation method seven: Combination Figures 1 to 4The present embodiment further includes a plurality of protective skins; one end of the Y1-axis slide 10 is connected to one end of the Y2-axis slide 11 with a protective skin, the other end of the Y1-axis slide 10 is connected to one end of the Y-axis base with a protective skin, and the other end of the Y2-axis slide 11 is connected to the other end of the Y-axis base with a protective skin; one end of the X1-axis slide 14 is connected to one end of the X1-axis base with a protective skin, and the other end of the X1-axis slide 14 is connected to the other end of the X1-axis base with a protective skin; the X2-axis slide 1 5 has a protective skin connected to one end of the X2 axis base, and the other end of the X2 axis slide 15 has a protective skin connected to the other end of the X2 axis base; one end of the Z1 axis slide 16 has a protective skin connected to one end of the Z1 axis base 21, and the other end of the Z1 axis slide 16 has a protective skin connected to the other end of the Z1 axis base 21; one end of the Z2 axis slide 17 has a protective skin connected to one end of the Z2 axis base 23, and the other end of the Z2 axis slide 17 has a protective skin connected to the other end of the Z2 axis base 23. In this way, by arranging a protective skin on the outside of the transmission component, dust can be prevented from entering the transmission component, which can protect the component and increase the service life of the transmission component. Other components and connection relationships are the same as those in the first, second, third, fourth, fifth or sixth embodiments.

[0033] Specific implementation method eight: Combination Figures 1 to 4 This embodiment is described. A grinding method of this embodiment uses a gantry-type double-station ultra-precision grinding machine tool to grind a sapphire free-form surface optical element, which includes the following steps: Step 1: Grinding of sapphire free-form optical elements: A deterministic compensating grinding process for the surface error of a sapphire free-form surface optical element is performed on a workstation 1 of a grinding machine tool, the sapphire free-form surface optical element is mounted on a B1 turntable, and the surface error of the sapphire free-form surface optical element is measured in situ using a detection tool 9 on the workstation 1 to obtain original measurement information, the original measurement information including grinding lines (intermediate frequency) and surface roughness (high frequency), and then the error separation is performed on the measured original measurement information to obtain discrete measurement information; a grinding wheel error model is established using the discrete measurement information to generate a grinding wheel trajectory for compensation processing, and finally the grinding process of the sapphire free-form surface optical element is completed; Step 2: Polishing of sapphire free-form optical elements: The Y1-axis slide 10 is driven by the Y-axis linear drive mechanism, and the B1-axis rotation drive mechanism 12, the B1 turntable and the sapphire free-form surface optical element on the B1 turntable on the Y1-axis slide 10 are driven to move from the station 1 of the grinding machine tool to the station 2 of the grinding machine tool along the Y-axis guide rail 18 to perform polishing after grinding; Step 3: Inspection of sapphire free-form optical components: The detection tool (9) on the second station is used to measure the high-frequency errors on the surface of the sapphire free-form optical element after grinding and polishing to check whether the workpiece meets the processing requirements.

[0034] Specific implementation method nine: Combination Figures 1 to 4 This embodiment describes the specific process of performing error separation on the original measurement information obtained by measurement to obtain discrete measurement information as follows: The error separation is performed using a wavelet decomposition method, comprising the following steps: Wavelet decomposition is based on wavelet transform and uses wavelet basis functions to decompose the original measurement information at different scales. , the wavelet decomposition is calculated by formula (1): (1) In formula (1), L is the scale range, is the decomposed function, is the stretch factor, is the translation factor, is the time from the start of collection to the end of collection, is the time scale, is the function that needs to be decomposed, is the wavelet function, yes The basis wavelet function, yes The average value of the basis wavelet function Calculated by formula (2): , , (2) In formula (2), the stretch factor and translation factor Control the stretching and translation of the base wavelet to form wavelet bases of different scales; Since the measured data set consists of discrete points, the stretch factor and translation factor Discretization is performed, and the discrete formula is calculated as formula (3): , , , , (3) In formula (3), is the stretch factor constant, is the translation factor constant, is the factor degree, is a proportional plural, is the set of integers; Basis wavelet function Discretize, discrete wavelet function Calculated by formula (4): (4) Discrete wavelet decomposition Calculated by formula (5): (5) The discrete orthogonal wavelet Daubechies is used to separate the contour error of the original measurement information, and the scaling function To approximate the measured signal, the scaling function is calculated by formula (6): (6) final, The wavelet decomposition calculation formula is as follows: (7) In formula (7): and The scaling functions are and discrete wavelet function The coefficient of Combining the two expressions in formula (7), we can get , and then the formula (7) Substituting into formula (5), we get the discrete wavelet decomposition of the discrete measurement signal: , discrete wavelet decomposition It is used to process the original measurement information and convert the continuous original measurement information into discrete measurement information. Other components and connection relationships are the same as those of the first, second, third, fourth, fifth, sixth, seventh or eighth specific implementation modes.

[0035] Specific implementation method ten: Combination Figures 1 to 4 The present embodiment is described. The specific process of using the discrete measurement information to establish a grinding wheel error model, generate a grinding wheel trajectory for compensation processing, and finally complete the grinding process of the sapphire free-form surface optical element is as follows: Any point on the grinding path The surface normal vector Calculated by formula (8): (8) In formula (8): and The equations of the double-tapered free-form surface are Axis and The partial derivatives of the axes, and Yes The second-order derivative of , and In the Cartesian coordinate system , and The unit vector of the axis; Wheel center at each contact point on the grinding path Correction position Calculated by formula (9): (9) In formula (9): Corrected grinding wheel radius and grinding wheel waviness error In the normal vector direction, is a unit vector, is the radial deviation of the grinding wheel along the X direction; The contact point between the grinding wheel and the workpiece on the grinding path at any given moment is , and use the vector Indicates that the position of the grinding wheel abrasive grain is , Grinding wheel waviness error Grinding wheel angle The arc of the grinding wheel cross section Corresponding angle, grinding wheel angle Calculated by formula (10), the angle between the center of the grinding wheel, the line connecting the contact point and the z-axis is Calculated by formula (11): (10) (11) Radial deviation of grinding wheel along X direction By unit vector Represents the unit vector Calculated by formula (12): (12) At this point, all variables in formula (9) have been solved, so the corrected grinding wheel center position is calculated , in fact, the center of rotation The position of is used to generate the grinding wheel trajectory for contour error compensation. The corrected rotation center Position vector Indicates that vector Calculated by the grinding wheel error model shown in formula (13): (13) In formula (13): is the grinding wheel radius, is the radius of curvature of the free-form surface at the contact point; Then the above discrete wavelet decomposition is performed as described in formula (5) Substitute the obtained discrete measurement information into formula (13) to obtain the vector Specific value of Finally, a grinding wheel error model is established through in-situ measurement and error separation, and a grinding wheel trajectory for compensation processing is generated; after the grinding wheel trajectory for compensation processing is generated, a gantry-type double-station ultra-precision grinding machine tool is used to grind the sapphire free-form surface optical element, and the X-axis component 5, Y-axis component 4, Z-axis component 6, B-axis component 7 and processing tool 8 on station one are linked to realize the grinding operation of the sapphire free-form surface optical element. Other components and connection relationships are the same as those of the first, second, third, fourth, fifth, sixth, seventh, eighth or ninth embodiments.

[0036] In this embodiment, when a gantry-type double-station ultra-precision grinding machine is used to grind sapphire free-form surface optical elements, the feed speed range of the X-axis component 5, Y-axis component 4, and Z-axis component 6 of the grinding machine is: 0.5~3mm / min, and the rotation speed of the processing tool 8 is 4000~5000rpm.

[0037] like Figure 5 As shown, the free-form surface is described as , showing half of the grinding wheel section and its rotation axis at the same time. The ideal grinding path for double-taper free-form surface contour error compensation is shown with the passing points The dotted line at the grinding wheel indicates the contact point between the grinding wheel and the workpiece on the grinding path at any given time. , and use the vector Indicates. Center of rotation and the center of the section arc Use vectors respectively and vector represents, and the vector You can use vector Therefore, in order to facilitate calculation, we use To develop the grinding wheel path for compensating machining. is the local surface normal vector Direction distance The uncorrected grinding wheel center position at . The axis of rotation is called the assumed axis of rotation , and in Point intersects with the grinding wheel surface. Point Also on this assumed rotation axis and in a direction parallel to plane and passes through the contact point On the plane. Figure 6Shown, showing the contact points The local region and unit vector around , , , and Definition, point and Point In straight line and Based on the above description and definition, a grinding wheel trajectory for contour error compensation is generated.

[0038] How it works Combination Figures 1 to 4 The working principle of the gantry type double-station ultra-precision grinding machine tool described in the present invention is described as follows: The processing mode of the present invention includes a serial processing mode and a parallel processing mode. For the sake of clarity and convenience, in the following content, the side of the X1 axis, Y1 axis, Z1 axis, and B1 axis is station one, and the side of the X2 axis, Y2 axis, Z2 axis, and B2 axis is station two. Figure 2 For reference, the left side of the machine tool beam 2 is workstation one, and the right side of the machine tool beam 2 is workstation two.

[0039] The serial processing mode is: after the processing of a pair of workpieces at station one is completed, the Y1-axis linear motor drives the Y1-axis slide 10, thereby driving the B1-axis rotation drive mechanism 12 and the processed workpiece placed thereon to switch positions between station one and station two along the Y-axis guide rail 18, or after the processing of a pair of workpieces at station two is completed, the Y2-axis linear motor drives the Y2-axis slide 11, thereby driving the B2-axis rotation drive mechanism 13 and the processed workpiece placed thereon to switch positions between station one and station two along the Y-axis guide rail 18.

[0040] When processing the workpiece using the processing tool 8 and the detection tool 9 at the workstation 1, the X1-axis linear motor drives the X1-axis slide 14, thereby driving the Z1-axis linear drive mechanism and the Z1-axis slide 16 to reciprocate along the X1-axis guide rail 19; the Z1-axis motor 22 drives the screw in the Z1-axis ball screw linear guide rail to rotate, driving the Z1-axis slide 16 to reciprocate along the Z-axis direction; the processing tool 8 and the detection tool 9 are installed on the Z1-axis slide 16, so they can move along the X-axis and Z-axis directions. The Y1-axis linear motor drives the Y1-axis slide 10, thereby driving the B1-axis rotation drive mechanism 12 to reciprocate along the Y-axis guide rail 18; the B1-axis rotation drive mechanism 12 drives the B1 turntable to rotate; the workpiece is clamped on the B1 turntable, so it can move along the Y direction and rotate around the Z direction. The X1 axis, Y1 axis, Z1 axis and B1 axis are linked, and the workpiece can be processed using the processing tool 8 at the workstation 1.

[0041] When the workpiece is processed by the processing tool 8 and the detection tool 9 at the second station, the X2-axis linear motor drives the X2-axis slide 15, thereby driving the Z2-axis linear drive mechanism and the Z2-axis slide 17 to reciprocate along the X2-axis guide rail 20; the Z2-axis motor 24 drives the screw in the Z2-axis ball screw linear guide rail to rotate, driving the Z2-axis slide 17 to reciprocate along the Z-axis direction; the processing tool 8 and the detection tool 9 are installed on the Z2-axis slide 17, so they can move along the X-axis and Z-axis directions. The Y2-axis linear motor drives the Y2-axis slide 11, thereby driving the B2-axis rotation drive mechanism 13 to reciprocate along the Y-axis guide rail 18; the B2-axis rotation drive mechanism 13 drives the B2 turntable to rotate; the workpiece is clamped on the B2 turntable, so it can move along the Y direction and rotate around the Z direction. The X2 axis, Y2 axis, Z2 axis and B2 axis are linked, and the workpiece can be processed by tools at the second station.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gantry type double-station ultra-precision grinding machine tool, characterized in that: It comprises a machine tool body, a Y-axis assembly (4), two X-axis assemblies (5), two Z-axis assemblies (6), two B-axis assemblies (7), two processing tools (8) and two detection tools (9); the machine tool body is a gantry-type machine tool body, which comprises a machine tool bed (1), a machine tool crossbeam (2) and two machine tool columns (3); the machine tool bed (1) is arranged horizontally along the Y-axis direction; the machine tool crossbeam (2) is arranged horizontally along the X-axis direction directly above the machine tool bed (1); two machine tool columns (3) are arranged vertically symmetrically on both sides below the machine tool crossbeam (2) along the Z-axis direction; the lower ends of the two machine tool columns (3) are connected to the machine tool bed ( 1) upper surfaces are fixedly connected, and the upper ends of the two machine tool columns (3) are fixedly connected to the lower surface of the machine tool crossbeam (2); the Y-axis assembly (4) comprises a Y-axis linear drive mechanism, a Y1-axis slide (10) and a Y2-axis slide (11), the Y-axis linear drive mechanism is installed on the upper part of the machine tool bed (1) along the Y-axis direction, and the Y1-axis slide (10) and the Y2-axis slide (11) are respectively installed at two movable ends of the Y-axis linear drive mechanism; the B-axis assembly (7) comprises a B1-axis rotation drive mechanism (12), a B1 turntable, a B2-axis rotation drive mechanism (13) and a B2 turntable, and the B1-axis rotation drive mechanism (12) and the B2-axis rotation drive mechanism (13) are respectively installed at two movable ends of the Y-axis linear drive mechanism. The Y1-axis slide (10) and the Y2-axis slide (11) are respectively installed, and the B1 turntable and the B2 turntable are respectively arranged above the B1-axis rotation drive mechanism (12) and the B2-axis rotation drive mechanism (13) and connected to their rotation shafts; the X-axis assembly (5) includes an X1-axis linear drive mechanism, an X1-axis slide (14), an X2-axis linear drive mechanism and an X2-axis slide (15), the X1-axis linear drive mechanism and the X2-axis linear drive mechanism are respectively installed symmetrically on the left and right sides of the machine tool crossbeam (2) along the X-axis direction, and the X1-axis slide (14) and the X2-axis slide (15) are respectively installed on the moving ends of the X1-axis linear drive mechanism and the X2-axis linear drive mechanism. The Z-axis assembly (6) comprises a Z1-axis linear drive mechanism, a Z1-axis slide (16), a Z2-axis linear drive mechanism and a Z2-axis slide (17); the Z1-axis linear drive mechanism and the Z2-axis linear drive mechanism are symmetrically mounted on the X1-axis slide (14) and the X2-axis slide (15) along the Z-axis direction, respectively; the Z1-axis slide (16) and the Z2-axis slide (17) are mounted on the moving ends of the Z1-axis linear drive mechanism and the Z2-axis linear drive mechanism, respectively; a processing tool (8) and a detection tool (9) are mounted on the Z1-axis slide (16); and a processing tool (8) and a detection tool (9) are mounted on the Z2-axis slide (17).

2. The gantry type double-station ultra-precision grinding machine tool according to claim 1 is characterized in that: The Y-axis linear drive mechanism comprises a Y-axis base, a Y-axis guide rail (18), a Y1-axis linear motor and a Y2-axis linear motor. The Y-axis base is mounted on the upper part of a machine tool bed (1). The Y-axis guide rail (18) is mounted on the Y-axis base along the Y-axis direction. The Y1-axis slide plate (10) and the Y2-axis slide plate (11) are both slidably connected to the Y-axis guide rail (18). The Y1-axis slide plate (10) and the Y2-axis slide plate (11) are respectively connected to the Y-axis guide rail (18) via the Y1-axis linear motor and the Y2-axis linear motor.

3. The gantry type double-station ultra-precision grinding machine tool according to claim 2 is characterized in that: The X1-axis linear drive mechanism comprises an X1-axis base, an X1-axis linear motor and an X1-axis guide rail (19); the X1-axis base is mounted on one side of a machine tool crossbeam (2); the X1-axis guide rail (19) is mounted on the X1-axis base along the X-axis direction; the X1-axis slide plate (14) is slidably connected to the X1-axis guide rail (19); the X1-axis slide plate (14) is connected to the X1-axis guide rail (19) via the X1-axis linear motor; and the X2-axis linear drive mechanism comprises an X2-axis base, an X2-axis linear motor and an X2-axis guide rail (20); the X2-axis base is mounted on the other side of the machine tool crossbeam (2); the X2-axis guide rail (20) is mounted on the X2-axis base along the X-axis direction; the X2-axis slide plate (15) is slidably connected to the X2-axis guide rail (20); the X2-axis slide plate (15) is connected to the X2-axis guide rail (20) via the X2-axis linear motor.

4. The gantry type double-station ultra-precision grinding machine tool according to claim 3 is characterized in that: The Z1-axis linear drive mechanism comprises a Z1-axis base (21), a Z1-axis motor (22), and a Z1-axis ball screw linear guide, wherein the Z1-axis base (21) is mounted on the X1-axis slide (14), the Z1-axis ball screw linear guide is provided on the outer side of the Z1-axis base (21) along the Z-axis direction, the Z1-axis motor (22) is mounted on the upper end of the Z1-axis base (21), the rotating shaft of the Z1-axis motor (22) is connected to the upper end of the screw in the Z1-axis ball screw linear guide, and the slider in the Z1-axis ball screw linear guide is fixedly connected to the Z1-axis slide (16); The Z2-axis linear drive mechanism comprises a Z2-axis base (23), a Z2-axis motor (24), and a Z2-axis ball screw linear guide. The Z2-axis base (23) is mounted on an X2-axis slide (15). The Z2-axis ball screw linear guide is provided on the outer side of the Z2-axis base (23) along the Z-axis direction. The Z2-axis motor (24) is mounted on the upper end of the Z2-axis base (23). The rotating shaft of the Z2-axis motor (24) is connected to the upper end of the screw in the Z2-axis ball screw linear guide. The slider in the Z2-axis ball screw linear guide is fixedly connected to the Z2-axis slide (17).

5. The gantry type double-station ultra-precision grinding machine tool according to claim 4 is characterized in that: The Z-axis assembly (6) further comprises two Z1-axis cylinder assemblies and two Z2-axis cylinder assemblies; the two Z1-axis cylinder assemblies are symmetrically arranged on both sides of the Z1-axis base (21); each Z1-axis cylinder assembly comprises a Z1-axis cylinder body (25), a Z1-axis cylinder connecting base (26) and a Z1-axis cylinder L-shaped connecting top plate (27); the lower end of the cylinder body of the Z1-axis cylinder body (25) is connected to the Z1-axis cylinder connecting base (26); the Z1-axis cylinder connecting base (26) is installed on the lower side of the Z1-axis slide (16); the piston rod end of the Z1-axis cylinder body (25) is connected to the Z1-axis cylinder L-shaped connecting top plate (27); the Z1-axis cylinder L-shaped connecting top plate (27) is installed On the upper side of the Z1 axis base (21); two Z2 axis cylinder assemblies are symmetrically arranged on both sides of the Z2 axis base (23), each Z2 axis cylinder assembly includes a Z2 axis cylinder body (28), a Z2 axis cylinder connecting base (29) and a Z2 axis cylinder L-shaped connecting top plate (30), the lower end of the cylinder body of the Z2 axis cylinder body (28) is connected to the Z2 axis cylinder connecting base (29), the Z2 axis cylinder connecting base (29) is installed on the lower side of the Z2 axis slide (17), the piston rod end of the Z2 axis cylinder body (28) is connected to the Z2 axis cylinder L-shaped connecting top plate (30), and the Z2 axis cylinder L-shaped connecting top plate (30) is installed on the upper side of the Z2 axis base (23).

6. The gantry type double-station ultra-precision grinding machine tool according to claim 5, characterized in that: The Y-axis guide rail (18), the X1-axis guide rail (19) and the X2-axis guide rail (20) are all liquid hydrostatic guide rails; the B1-axis rotation drive mechanism (12) and the B2-axis rotation drive mechanism (13) are both liquid-floating hydrostatic turntables; and the machine tool bed (1) is a granite bed.

7. The gantry type double-station ultra-precision grinding machine tool according to claim 6, characterized in that: The invention also includes a plurality of protective skins; one end of the Y1-axis slide (10) is connected to one end of the Y2-axis slide (11) by a protective skin, the other end of the Y1-axis slide (10) is connected to one end of the Y-axis base by a protective skin, and the other end of the Y2-axis slide (11) is connected to the other end of the Y-axis base by a protective skin; one end of the X1-axis slide (14) is connected to one end of the X1-axis base by a protective skin, and the other end of the X1-axis slide (14) is connected to the other end of the X1-axis base by a protective skin; one end of the X2-axis slide (15) is connected to the X2-axis base by a protective skin. One end of the seat is connected to a protective skin, and the other end of the X2-axis slide (15) is connected to the other end of the X2-axis base with a protective skin; one end of the Z1-axis slide (16) is connected to one end of the Z1-axis base (21) with a protective skin, and the other end of the Z1-axis slide (16) is connected to the other end of the Z1-axis base (21) with a protective skin; one end of the Z2-axis slide (17) is connected to one end of the Z2-axis base (23) with a protective skin, and the other end of the Z2-axis slide (17) is connected to the other end of the Z2-axis base (23) with a protective skin.

8. A grinding method, characterized in that: The gantry-type double-station ultra-precision grinding machine tool described in claim 7 is used to grind sapphire free-form surface optical elements, which includes the following steps: Step 1: Grinding of sapphire free-form optical elements: Performing deterministic compensatory grinding of the surface error of a sapphire free-form surface optical element at station 1 of a grinding machine, mounting the sapphire free-form surface optical element on a B1 turntable, and using a detection tool (9) at station 1 to perform in-situ measurement of the surface error of the sapphire free-form surface optical element to obtain raw measurement information, wherein the raw measurement information includes grinding lines and surface roughness, and then performing error separation on the raw measurement information to obtain discrete measurement information; using the discrete measurement information to establish a grinding wheel error model, generating a grinding wheel trajectory for compensation processing, and finally completing the grinding of the sapphire free-form surface optical element; Step 2: Polishing of sapphire free-form optical elements: The Y1-axis slide (10) is driven by the Y-axis linear drive mechanism, and the B1-axis rotation drive mechanism (12), the B1 turntable and the sapphire free-form surface optical element on the B1 turntable on the Y1-axis slide (10) are driven to move along the Y-axis guide rail (18) from the first station of the grinding machine tool to the second station of the grinding machine tool to perform polishing after grinding; Step 3: Inspection of sapphire free-form optical components: The detection tool (9) on the second station is used to measure the high-frequency errors on the surface of the sapphire free-form optical element after grinding and polishing to check whether the workpiece meets the processing requirements.

9. The grinding method according to claim 8, characterized in that: The specific process of performing error separation on the original measurement information obtained by measurement and obtaining discrete measurement information is as follows: The error separation is performed using a wavelet decomposition method, comprising the following steps: Wavelet decomposition is based on wavelet transform and uses wavelet basis functions to decompose the original measurement information at different scales. , the wavelet decomposition is calculated by formula (1): （1） In formula (1), L is the scale range, is the decomposed function, is the stretch factor, is the translation factor, is the time from the start of collection to the end of collection, is the time scale, is the function that needs to be decomposed, is the wavelet function, yes The basis wavelet function, yes The average value of the basis wavelet function Calculated by formula (2): ， ， （2） In formula (2), the stretch factor and translation factor Control the stretching and translation of the base wavelet to form wavelet bases of different scales; Since the measured data set consists of discrete points, the stretch factor and translation factor Discretization is performed, and the discrete formula is calculated as formula (3): ， ， ， ， （3） In formula (3), is the stretch factor constant, is the translation factor constant, is the factor degree, is a proportional plural, is the set of integers; Basis wavelet function Discretize, discrete wavelet function Calculated by formula (4): （4） Discrete wavelet decomposition Calculated by formula (5): （5） The discrete orthogonal wavelet Daubechies is used to separate the contour error of the original measurement information, and the scaling function To approximate the measured signal, the scaling function is calculated by formula (6): （6） final, The wavelet decomposition calculation formula is as follows: （7） In formula (7): and The scaling functions are and discrete wavelet function The coefficient of Combining the two expressions in formula (7), we can get , and then the formula (7) Substituting into formula (5), we get the discrete wavelet decomposition of the discrete measurement signal: , discrete wavelet decomposition Used to process raw measurement information and convert continuous raw measurement information into discrete measurement information.

10. The grinding method according to claim 9, characterized in that: The specific process of establishing a grinding wheel error model using the discrete measurement information, generating a grinding wheel trajectory for compensation processing, and finally completing the grinding process of the sapphire free-form surface optical element is as follows: Any point on the grinding path The surface normal vector Calculated by formula (8): （8） In formula (8): and The equations of the double-tapered free-form surface are Axis and The partial derivatives of the axes, and Yes The second-order derivative of , and In the Cartesian coordinate system , and The unit vector of the axis; Wheel center at each contact point on the grinding path Correction position Calculated by formula (9): （9） In formula (9): Corrected grinding wheel radius and grinding wheel waviness error In the normal vector direction, is a unit vector, is the radial deviation of the grinding wheel along the X direction; The contact point between the grinding wheel and the workpiece on the grinding path at any given moment is , and use the vector Indicates that the position of the grinding wheel abrasive grain is , Grinding wheel waviness error Grinding wheel angle The arc of the grinding wheel cross section Corresponding angle, grinding wheel angle Calculated by formula (10), the angle between the center of the grinding wheel, the line connecting the contact point and the z-axis is Calculated by formula (11): （10） （11） Radial deviation of grinding wheel along X direction By unit vector Represents the unit vector Calculated by formula (12): （12） At this point, all variables in formula (9) have been solved, so the corrected grinding wheel center position is calculated , in fact, the center of rotation The position of is used to generate the grinding wheel trajectory for contour error compensation. The corrected rotation center Position vector Indicates that vector Calculated by the grinding wheel error model shown in formula (13): （13） In formula (13): is the grinding wheel radius, is the radius of curvature of the free-form surface at the contact point; Then the above discrete wavelet decomposition is performed as described in formula (5) Substitute the obtained discrete measurement information into formula (13) to obtain the vector Specific value of Finally, a grinding wheel error model is established through in-situ measurement and error separation, and a grinding wheel trajectory for compensatory processing is generated. After the grinding wheel trajectory for compensatory processing is generated, a gantry-type double-station ultra-precision grinding machine tool is used to grind the sapphire free-form surface optical element. The X-axis assembly (5), Y-axis assembly (4), Z-axis assembly (6), B-axis assembly (7) and processing tool (8) on station one are linked to achieve the grinding operation of the sapphire free-form surface optical element.

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