Low coupling contact type scanning probe device based on parallel spring leaf set

Abstract

The application provides a low coupling contact type scanning probe device based on parallel spring piece groups, and belongs to the technical field of precision measurement. The application comprises a probe protection device, a three-axis flexible guide mechanism and a displacement detection system. The three-axis flexible guide mechanism adopts three pairs of parallel spring piece groups, is connected in series through a fixed plate and a translational plate, forms a low coupling guide mechanism with independent X / Y / Z three-axis movement, combines a gravity balance device spring to offset the influence of Z direction dead weight, reduces cross coupling error, and improves reset accuracy and dynamic response. The displacement detection system is based on a single laser and a biased split light prism, divides the light beam to horizontal and vertical four-quadrant detectors, synchronously captures three-dimensional displacement signals, eliminates Abbe error, and integrates a closed loop feedback coupling error compensation module to correct residual coupling error in real time through a least square method. The application solves the problems of easy fatigue of elastic elements, uneven rigidity in each direction, poor dynamic performance and high cost, and has the advantages of high precision, long service life and low cost.

Description

Technical Field

[0001] This invention relates to a low-coupling contact scanning probe device based on a parallel reed assembly, belonging to the field of precision measurement technology. Background Technology

[0002] As a key component of precision measuring instruments, the 3D probe plays a crucial role in high-precision measuring equipment such as coordinate measuring machines (CMMs) and gear measuring centers. Its accuracy and performance directly determine the precision and efficiency of the entire measurement system. With the rapid development of precision measurement technology, the accuracy requirements and comprehensive mechanical performance standards for 3D probes are increasingly demanding. Currently, research in this field mainly focuses on the structural optimization of the three-axis guiding mechanisms and the improvement of the overall performance of the probe system. Scanning probes, also known as linear probes, effectively solve technical challenges such as anisotropy, pre-stroke error, and sampling point limitations compared to trigger-type probes through innovative probe structure design and measurement methods. The core technology of this type of probe lies in designing a frictionless, backflip-error-free, and highly sensitive micro-displacement system to ensure that its output is proportional to the probe offset, while possessing multiple functions such as precise spatial coordinate point positioning and efficient scanning of curves and surfaces. This design not only improves the accuracy and efficiency of measurement but also provides a more reliable solution for measuring complex workpieces.

[0003] Traditional contact scanning probes often suffer from the following structural design problems: 1. Elastic elements are prone to fatigue deformation, leading to decreased reset accuracy; 2. Inconsistent stiffness in different directions affects measurement stability; 3. Complex structure and high manufacturing cost; 4. Poor dynamic response characteristics, making it difficult to adapt to high-speed scanning measurements. For example, among foreign products, the Renishaw SP80 probe, although employing a nested reed structure, suffers from anisotropy and installation / adjustment difficulties; Zeiss's VAST probe, while exhibiting good dynamic performance, suffers from insufficient Z-axis sensitivity; and the Klingberg K3D probe has a complex mechanical structure and high manufacturing cost. Domestically, the nested double-reed structure probe developed by Zhang Guoxiong's team at Tianjin University, while compact, suffers from errors in transmission and inconsistent dynamic characteristics. Currently, the scanning probe devices produced by Harbin Measuring & Cutting Tool Group Co., Ltd. mostly use inductive sensors, which have drawbacks such as low frequency response making them unsuitable for fast dynamic applications, complex conversion circuits, and zero-position errors. Furthermore, a three-story parallel spring three-dimensional probe guide mechanism disclosed in patent US4660296 by the German company Zeiss, although simple in structure and easy to install and debug, has an excessively large longitudinal dimension and different masses of moving parts in each layer, making it difficult to maintain consistent dynamic characteristics in each guiding direction. In patent US5029398, the German company Ertl proposed a three-dimensional probe guide mechanism composed of parallel springs and flexible hinges combined in a certain way. Although the axial movements can be decoupled, this probe structure is more complex and requires higher precision in manufacturing, assembly, and debugging, thus resulting in higher manufacturing costs.

[0004] In summary, there is often a conflict between simple probe structure and high-precision measurement. To achieve complete decoupling of the three-axis guiding mechanism, it is necessary to introduce hinges or other flexible structures as decoupling components, or to adopt a more complex parallel structure with separate displacement detection systems for each axis, which will also introduce Abbe error. This invention employs three pairs of orthogonally nested parallel reed groups, an integrated photoelectric detection system, and a dynamic error compensation algorithm. It features a simple structure, convenient manufacturing and assembly, and achieves near-complete decoupling of three-dimensional micro-displacement measurement. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of the conflict between simple probe structure and high measurement accuracy in the existing technology, and to provide a low-coupling contact scanning probe device based on a parallel reed group.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A low-coupling contact scanning probe device based on a parallel reed assembly includes a probe protection device, a triaxial flexible guide mechanism, and a displacement detection system;

[0008] The triaxial flexible guide mechanism is housed inside the probe housing of the probe protection device and the two are detachably connected; the displacement detection system is housed inside the probe housing and is installed on both the probe housing and the triaxial flexible guide mechanism.

[0009] The triaxial flexible guiding mechanism includes a probe, an XZ-axis guiding mechanism, and a Y-axis guiding mechanism; the XZ-axis guiding mechanism and the Y-axis guiding mechanism are orthogonally nested; the lower end face of the Y-axis guiding mechanism is fixedly connected to the probe.

[0010] The XZ axial guiding mechanism includes an X-axis guiding mechanism, a Z-axis guiding mechanism, and a gravity balancing device spring; the X-axis guiding mechanism is nested and fixed inside the Z-axis guiding mechanism, and the two ends of the gravity balancing device spring are fixedly connected to one end of the X-axis guiding mechanism and one end of the Z-axis guiding mechanism, respectively.

[0011] Preferably, the X-axis guiding mechanism includes a pair of springs, an X-axis fixed plate, and an X-axis translational plate; the X-axis fixed plate and the X-axis translational plate are both horizontally arranged and directly opposite each other, and the pair of springs are fixedly connected to the left and right sides of the X-axis fixed plate and the X-axis translational plate.

[0012] The Z-axis guiding mechanism includes a pair of spring plates, a Z-axis fixed plate, and a Z-axis translational plate. The Z-axis fixed plate and the Z-axis translational plate are both vertical and arranged facing each other. The pair of spring plates are fixedly connected to the upper and lower ends of the Z-axis fixed plate and the Z-axis translational plate. A partition plate is horizontally arranged on the left side of the Z-axis translational plate. There is a gap between the partition plate and the Z-axis fixed plate.

[0013] The X-axis translational plate has a long strip-shaped through hole at its center, through which the Z-axis guide mechanism passes. The Z-axis guide mechanism passes through the long strip-shaped through hole, and the Z-axis fixing plate is fixedly connected to the left side of the inner wall of the long strip-shaped through hole. There is a gap between the Z-axis translational plate and the long strip-shaped through hole.

[0014] The two ends of the spring of the gravity balancing device are fixedly connected to the lower end face of the X-axis fixed plate and the upper end face of the Z-axis translational plate.

[0015] The Y-axis guiding mechanism includes a pair of spring contacts, a Y-axis fixing plate, and a probe base; the upper end face of the Y-axis fixing plate is fixedly connected to the lower end face of the spacer plate, and the Y-axis fixing plate and the probe base are both horizontally and directly opposite each other, and the pair of spring contacts are fixedly connected to the front and rear sides of the Y-axis fixing plate and the probe base.

[0016] The probe is fixedly connected to the center of the lower end face of the probe base.

[0017] Preferably, the probe protection device includes a probe housing and a mounting handle; one end of the probe housing is closed and the other end is open, and the closed end of the probe housing is provided with a mounting handle; the X-axis fixing plate is detachably connected to the closed end of the probe housing.

[0018] Preferably, the displacement detection system includes a laser, a bias beam splitter, and two quadrant detectors; the laser is fixed inside the probe housing by a laser adjustment seat; the bias beam splitter is fixed inside the probe housing by a beam splitter adjustment seat, and the bias beam splitter is positioned on the laser's emission optical path; the two quadrant detectors are respectively horizontally and vertically positioned and are both fixedly connected to the upper end face of the probe base; the bias beam splitter divides the incident beam into two paths, namely a horizontal optical path and a vertical optical path, wherein the horizontally positioned quadrant detector is positioned on the vertical optical path of the bias beam splitter, and the vertically positioned quadrant detector is positioned on the horizontal optical path of the bias beam splitter.

[0019] Preferably, the pair of springs one, the pair of springs two, and the pair of springs three are all the same in shape and size, and are covered with clamps on both sides; all the springs are made of beryllium bronze; and the clamps are made of silicon carbide aluminum alloy.

[0020] Preferably, the upper and lower ends of the gravity balancing device spring are respectively fixed with threaded columns, and the lower end face of the X-axis fixed plate and the upper end face of the Z-axis translational plate are provided with threaded holes in opposite positions. The threaded column at the upper end of the gravity balancing device spring is threadedly engaged with the threaded hole at the lower end face of the X-axis fixed plate, and the threaded column at the lower end of the gravity balancing device spring is threadedly engaged with the threaded hole at the upper end face of the Z-axis translational plate.

[0021] Preferably, the laser emission path and the two optical paths after beam splitting by the bias beam splitter coincide with the spatial axes of the X-axis, Y-axis and Z-axis.

[0022] Preferably, a horizontally positioned four-quadrant detector is used to detect the X / Y axis spot displacement;

[0023] A vertically positioned four-quadrant detector is used to detect the Z-axis light spot displacement, and the light spot displacement is converted into a three-dimensional voltage signal output through photoelectric conversion.

[0024] Preferably, the scanning probe device further includes a closed-loop feedback coupling error compensation module, the input end of which is connected to the output end of the four-quadrant detector.

[0025] The closed-loop feedback coupling error compensation module is used to process the original three-dimensional voltage signal output by the four-quadrant detector, and then separates each axial coupling component in real time using the least squares method, and performs dynamic compensation using the truth value correction module, and finally outputs the displacement truth value that is close to complete decoupling.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This invention uses three pairs of parallel spring sheets of identical shape and size as the guide mechanism of the probe, and cleverly constructs a planar translational plate that moves together with the probe base to form a "coplanar" structure, so that the movement of the probe base in any direction is translational, reducing Abbe error in the plane and effectively improving the accuracy of the probe device.

[0028] 2. In this invention, three pairs of parallel reed groups are connected in series through intermediate elements, a translation plate and a fixed plate, and the axial movements of each are independent of each other, which significantly reduces the cross-coupling error; the design of the clamping plate improves the rigidity of the guide mechanism without increasing the number of reeds, while maintaining high sensitivity.

[0029] 3. This invention employs a symmetrical nested layout of three pairs of parallel reed groups, transmitting motion through the elastic deformation of the reeds themselves. The installation direction of each pair of parallel reed groups is orthogonal to the direction of the motion degree of freedom (e.g., the parallel reed groups in the X-axis guide mechanism constrain Y / Z-axis displacement), forming multi-directional elastic support and eliminating the microscopic backlash caused by mechanical contact in traditional hinge structures. The rotation of traditional hinges relies on the fit between the shaft and the hole, while the reed achieves equivalent rotation through bending deformation, eliminating shaft-hole clearance. Therefore, this invention is simple and compact, small in size and light in weight, with no shaft-hole clearance and no friction during movement, avoiding the disadvantages of complex and inconvenient traditional scanning probe structures; simultaneously, the reed structure, as a flexible unit, has good recovery performance, greatly extending the probe's service life under the same measurement conditions and reducing production costs.

[0030] 4. The present invention employs a displacement detection system. The integrated design of a single light source and dual detectors eliminates the installation error of multiple sensors and avoids the Abbe error caused by the non-coincidence of the optical path with the spatial axes of the measurement X, Y and Z axes. The displacement in three dimensions is detected synchronously by the same optical system, which simplifies the structure and improves the consistency of the system.

[0031] 5. To address the coupling error caused by the mechanical structure, this invention proposes a closed-loop feedback coupling error compensation algorithm to compensate for the measured values ​​in real time, thereby achieving a three-dimensional measurement system that is closer to complete decoupling and improving the overall accuracy and reliability of the probe.

[0032] 6. This invention, through the coordinated design of flexible reed guidance and photoelectric detection in the displacement detection system, makes the reed deformation and the spot offset have a 1:1 linear relationship. While ensuring measurement accuracy, it significantly reduces system complexity and solves the problems of easy fatigue of elastic elements, uneven stiffness in all directions, poor dynamic performance and high cost of traditional probes. It is suitable for high-precision scenarios such as precision machining, coordinate measuring machine, high-speed scanning and micro-nano manufacturing. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the external structure of the low-coupling contact scanning probe device based on parallel reed groups according to the present invention.

[0034] Figure 2 This is a schematic diagram of the three-axis flexible guide mechanism of the present invention.

[0035] Figure 3 This is a top view schematic diagram of the three-axis flexible guide mechanism of the present invention.

[0036] Figure 4 This is a schematic diagram of the XZ axial guide mechanism of the present invention.

[0037] Figure 5 This is a schematic diagram of the left side of the three-axis flexible guide mechanism of the present invention.

[0038] Figure 6 for Figure 5 An enlarged schematic diagram of the C-section structure.

[0039] Figure 7 This is a right-side structural schematic diagram of the three-axis flexible guide mechanism of the present invention.

[0040] Figure 8 for Figure 7 AA sectional view.

[0041] Figure 9 This is a schematic diagram of the main structure of the three-axis flexible guide mechanism of the present invention.

[0042] Figure 10 for Figure 9 BB cross-sectional view.

[0043] Figure 11 This is a schematic diagram of the displacement detection system of the present invention.

[0044] Figure 12 This is a schematic diagram of the spring structure of a gravity balancing device.

[0045] Figure 13 This is a schematic diagram illustrating the sources of coupling error in this invention; wherein,

[0046] Figure 13 (a) is a schematic diagram of the sources of X-guided coupling error;

[0047] Figure 13 (b) is a schematic diagram of the sources of Y-guided coupling error;

[0048] Figure 13 (c) is a schematic diagram of the source of Z-guided coupling error.

[0049] Figure 14 This is a logic block diagram of the error compensation algorithm of the present invention.

[0050] In the figure, the reference numerals are as follows: 1 is the probe housing; 2 is a pair of springs; 3 is the mounting handle; 4 is the fastening screw; 5 is the probe; 6 is the threaded hole; 7 is the XZ axis guiding mechanism; 701 is the X axis fixing plate; 702 is the X axis translation plate; 703 is the Z axis fixing plate; 704 is the Z axis translation plate; 705 is the spacer plate; 8 is the Y axis guiding mechanism; 801 is the Y axis fixing plate; 9 is the displacement detection system; 901 is the laser; 902 is the laser adjustment seat; 903 is the bias beam splitter; 904 is the beam splitter adjustment seat; 905 is the four-quadrant detector; 10 is the probe base; 11 is the gravity balance device spring; 12 is a pair of springs; 13 is a pair of springs; 14 is the clamping plate; and 15 is the pressure plate. Detailed Implementation

[0051] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation methods are given, but the protection scope of the present invention is not limited to the following embodiments. Specific implementation method one:

[0053] The present invention discloses the external structure of a low-coupling contact scanning probe device based on a parallel reed assembly, as follows: Figure 1 As shown, it includes a probe protection device, a triaxial flexible guide mechanism, and a displacement detection system 9; the entire triaxial flexible guide mechanism is set inside the probe housing 1 of the probe protection device, protected by the probe housing 1, and the two are detachably connected; the probe protection device includes the probe housing 1 and the mounting handle 3; one end of the probe housing 1 is closed, and the other end is open, and the closed end of the probe housing 1 is provided with the mounting handle 3; it facilitates the installation and use of the scanning probe device.

[0054] like Figure 2 As shown, the triaxial flexible guiding mechanism includes a probe 5, an XZ-axis guiding mechanism 7, and a Y-axis guiding mechanism 8; the XZ-axis guiding mechanism 7 and the Y-axis guiding mechanism 8 are orthogonally nested; the lower end face of the Y-axis guiding mechanism 8 is fixedly connected to the probe 5; the XZ-axis guiding mechanism 7 is as follows... Figure 4 As shown, the XZ axial guide mechanism 7 includes an X-axis guide mechanism, a Z-axis guide mechanism, and a gravity balance device spring 11; the X-axis guide mechanism is nested and fixed inside the Z-axis guide mechanism, and the two ends of the gravity balance device spring 11 are fixedly connected to the X-axis guide mechanism and the Z-axis guide mechanism, respectively.

[0055] The X-axis guiding mechanism includes a pair of spring plates 2, an X-axis fixed plate 701, and an X-axis translational plate 702; the specific structure is as follows: the X-axis fixed plate 701 is detachably connected to the closed end of the probe housing 1 by fastening screws 4, such as... Figure 3As shown, the X-axis fixed plate 701 has six threaded holes 6. The probe housing 1 is threadedly connected to the threaded holes 6 on the X-axis fixed plate 701 by fastening screws 4, thereby fixing the probe housing 1 to the X-axis fixed plate 701; serving as the reference mounting surface for the entire device. The X-axis fixed plate 701 and the X-axis translational plate 702 are both horizontally and vertically aligned. A pair of spring plates 2 are fixedly connected to the left and right sides of the X-axis fixed plate 701 and the X-axis translational plate 702. The pair of spring plates 2 have the same shape and size, and are wrapped with clamping plates 14 on both sides to enhance rigidity. The clamping plates 14 are fixedly connected to the spring plates by adhesive bonding. The thickness of the clamping plates 14 is optimized according to the deformation requirements of the spring plates to ensure the linear guiding accuracy of the X-axis. A pair of spring plates 2 are fixedly connected to the left and right sides of the X-axis fixed plate 701 and the X-axis translational plate 702 by screws; or adhesive is applied to both sides of the spring plates, one side of the spring plate is fixedly connected to the pressure plate 15 by adhesive bonding, and the other side is fixedly connected to the left and right sides of the X-axis fixed plate 701 and the X-axis translational plate 702 by adhesive bonding; thus forming an X-axis flexible structure. When the probe 5 is subjected to external force, the X-axis translational plate 702 generates a micro-displacement through the elastic deformation of the pair of spring plates 2, forming an X-axis guiding mechanism.

[0056] like Figure 7 and Figure 8 As shown, the Z-axis guiding mechanism includes a pair of spring plates 12, a Z-axis fixed plate 703, and a Z-axis translational plate 704. The Z-axis fixed plate 703 and the Z-axis translational plate 704 are both vertically aligned and face each other. The pair of spring plates 12 are fixedly connected to the upper and lower ends of the Z-axis fixed plate 703 and the Z-axis translational plate 704. A spacer plate 705 is horizontally arranged on the left side of the Z-axis translational plate 704. There is a gap between the spacer plate 705 and the Z-axis fixed plate 703. The center of the X-axis translational plate 702 has an elongated through-hole through which the Z-axis guiding mechanism passes. The Z-axis guiding mechanism passes through the elongated through-hole, and the Z-axis fixed plate 703 is fixedly connected to the left side of the inner wall of the elongated through-hole by adhesive. There is a gap between the Z-axis translational plate 704 and the elongated through-hole. The Z-axis translational plate 704 and the X-axis translational plate 702 do not directly contact each other, leaving a certain amount of space for movement. In a pair of springs 12, the two springs are identical in shape and size, and each spring is wrapped with a clamping plate 14 on both sides to improve bending stiffness. The gravity balancing device spring 11 is fixedly connected at both ends to the lower end face of the X-axis fixed plate 701 and the upper end face of the Z-axis translational plate 704, as shown below. Figure 12As shown, the upper and lower ends of the gravity balancing device spring 11 are respectively provided with threaded posts. The lower end face of the X-axis fixed plate 701 and the upper end face of the Z-axis translational plate 704 are provided with threaded holes in opposite positions. When installing the gravity balancing device spring 11, first thread the upper end of the gravity balancing device spring 11 is threaded into the threaded hole on the lower end face of the X-axis fixed plate 701, and then thread the lower end of the gravity balancing device spring 11 is threaded into the threaded hole on the upper end face of the Z-axis translational plate 704. The pair of spring plates 12 and the pressure plate 15 on the upper side of the Z-axis translational plate 704 are also provided with threaded holes in opposite positions. The gravity balancing device spring 11 passes through the pair of spring plates 12 and the pressure plate 15 and is threaded into the threaded hole on the upper end face of the Z-axis translational plate 704. The threaded holes on the X-axis fixed plate 701 and the Z-axis translational plate 704 have a certain machining allowance. By screwing in / out the threads, the compression of the gravity balancing device spring 11 is changed, thereby adjusting the preload and ensuring the linearity of the Z-axis displacement detection.

[0057] like Figure 9 and Figure 10 As shown, a pair of spring sheets 12 are fixedly connected to the upper and lower ends of the Z-axis fixed plate 703 and the Z-axis translational plate 704 by screws; or adhesive is applied to both sides of the spring sheets, one side of the spring sheet is fixedly connected to the pressure plate 15 by adhesive, and the other side is fixedly connected to the upper and lower ends of the Z-axis fixed plate 703 and the Z-axis translational plate 704 by adhesive; thus forming a Z-axis flexible structure. When the probe 5 is subjected to external force, the Z-axis translational plate 704 generates a micro-displacement through the elastic deformation of the pair of spring sheets 12, constituting a Z-axis guiding mechanism.

[0058] The Y-axis guiding mechanism is as follows Figure 5 and Figure 6As shown, the Y-axis guiding mechanism 8 includes a pair of spring plates 13, a Y-axis fixing plate 801, and a probe base 10. The upper end face of the Y-axis fixing plate 801 is fixedly connected to the lower end face of the spacer plate 705. The Y-axis fixing plate 801 and the probe base 10 are both horizontally aligned and directly opposite each other. The pair of spring plates 13 are fixedly connected to the front and rear sides of the Y-axis fixing plate 801 and the probe base 10. The probe 5 is fixed to the center of the lower end face of the probe base 10 by a threaded connection. It is used to contact the workpiece being measured and transmit three-dimensional displacement. The two spring plates in the pair of spring plates 13 have the same shape and size. Each spring plate is wrapped with a clamping plate 14 on both sides to optimize the Y-axis stiffness and improve the bending stiffness. Each spring is fixed to the front and rear sides of the Y-axis fixing plate 801 and the probe base 10 with fastening screws at both ends, or adhesive is applied to both sides of the spring, with one side of the spring fixed to the pressure plate 15 by adhesive bonding, and the other side fixed to the front and rear sides of the Y-axis fixing plate 801 and the probe base 10 by adhesive bonding; thus forming a flexible structure in the Y-axis direction. When the probe 5 is subjected to external force, the probe base 10 generates a micro-displacement through the elastic deformation of a pair of springs 13, forming a Y-axis guiding mechanism.

[0059] Three pairs of parallel reed groups: one pair of reed 12, one pair of reed 212, and one pair of reed 313 are connected in series through an intermediate translational plate and a fixed plate, so that all axial movements are translational, significantly reducing cross-coupling errors. The design of the clamping plate 14 improves the rigidity of the guiding mechanism without increasing the number of reeds, while maintaining high sensitivity. The specific working process is as follows: the three pairs of parallel reed groups control independent movements in three directions respectively. When the probe 5 measures an object, only the reeds play a flexible guiding role, and the other connecting parts are rigidly connected; the X-axis fixed plate 701 is fixedly connected to the probe housing 1 by fastening screws 4. When the probe 5 moves along the X direction, the X-axis fixed plate 701 acts as a fixed support, and the X-axis translational plate 702 drives the pair of reed 12 to achieve X-axis guidance, while the displacement in the Y and Z directions does not change; in the Z-axis guiding mechanism, the outer wall of the Z-axis fixed plate 703 is fixedly connected to the inner wall of the left side of the rectangular through hole of the X-axis translational plate 702. When the probe 5 moves along the Z direction, the outer wall of the Z-axis fixed plate 703 is fixedly connected to the inner wall of the left side of the rectangular through hole of the X-axis translational plate 702. During operation, the Z-axis fixed plate 703 serves as a fixed support, and the Z-axis translational plate 704 drives a pair of springs 12 to achieve Z-axis guidance, while the displacement in the X and Y directions remains unchanged. The Y-axis fixed plate 801 is glued to the Z-axis translational plate 704. When the probe 5 moves along the Y direction, the Y-axis fixed plate 801 and its connecting parts act as rigid components, and the probe base 10 drives a pair of springs 13 to achieve Y-axis guidance, while the displacement in the X and Z directions remains unchanged. Through simulation analysis, the three directions of movement are independent, and the structure is reasonable. On the one hand, it simplifies the spatial structure and reduces the probe size; on the other hand, it realizes multi-dimensional measurement and expands the scope of application.

[0060] In this embodiment, all the reeds are made of beryllium bronze, which has the characteristics of high elastic modulus and high fatigue resistance. The reeds are connected in series with the fixed plate through the middle translation plate, which can ensure that the movement of each axis is translational, thereby reducing the impact of coupling error on measurement accuracy.

[0061] In this embodiment, all clamping plates 14 are made of high-rigidity, lightweight silicon carbide aluminum alloy. The thickness of the clamping plates 14 is optimized according to the deformation requirements of the spring to enhance the stiffness of the spring and ensure the linear guiding function of the spring.

[0062] like Figure 11 As shown, the displacement detection system 9 achieves high-precision capture of three-dimensional displacement signals based on the laser collimation principle. The laser 901 is fixed to the probe housing 1 via a laser adjustment seat 902 and emits a collimated laser beam. A bias beam splitter 903 is positioned on the emission path of the laser 901, splitting the incident beam into two paths: a horizontal path and a vertical path. The emission path of the laser 901 and the two paths after splitting by the bias beam splitter 903 coincide with the spatial axes of the X, Y, and Z axes. A horizontally positioned quadrant detector 905 is placed on the vertical path of the bias beam splitter 903, and a vertically positioned quadrant detector 905 is placed on the horizontal path of the bias beam splitter 903. Therefore, the two paths after splitting by the bias beam splitter 903 are projected onto the two quadrant detectors 905, one horizontally and one vertically. The horizontally positioned quadrant detector 905 is used to detect displacement signals in the X and Y directions. When probe 5 is subjected to external force causing the reed to deform along the X / Y axes, probe base 10 drives the quadrant detector 905 to shift, and the light spot moves along the X / Y axes on the surface of quadrant detector 905. The vertically placed quadrant detector 905 is used to detect displacement signals in the Z direction. When deformed along the Z axis, the light spot moves along the Z-axis of the detector. The optical paths of laser 901 and bias beam splitter 903 coincide with the X / Y / Z three-axis spatial axis measurement directions. The optical path of displacement detection system 9 of this invention is fixed. When the low-coupling contact scanning probe device based on parallel reed groups is working, the position of the quadrant detector will change along the X / Y / Z axes, but no matter which direction the scanning probe device changes, the optical path always coincides with the three coordinate axes, thereby eliminating multi-sensor installation errors and Abbe errors.

[0063] The scanning probe device also includes a closed-loop feedback coupling error compensation module. The input of the closed-loop feedback coupling error compensation module is connected to the output of the four-quadrant detector 905. The closed-loop feedback coupling error compensation module is used to process the original three-dimensional voltage signal output by the four-quadrant detector 905, and then separates each axial coupling component in real time using the least squares method, and performs dynamic compensation using the truth value correction module, and finally outputs a displacement truth value that is close to complete decoupling.

[0064] Sources of coupling error, such as Figure 13 As shown, the X / Y / Z axial deviations are mainly due to the flexible guiding effect of the three sets of parallel reeds. Although the reeds have good linear guiding effect, when the probe 5 is subjected to force in the X direction, a pair of reeds 12 in the X-axis guiding mechanism undergoes elastic deformation, causing the X-axis reeds to tilt or bend slightly. This causes a slight change Z1 in the Z direction as the probe 5 moves along the X direction. When the probe 5 is subjected to force in the Y direction, a pair of reeds 13 in the Y-axis guiding mechanism undergoes elastic deformation, causing a slight tilt or bend in the Y-axis. This causes a slight change Z2 in the Z direction as the probe moves along the Y direction. When the probe is subjected to force in the Z direction, a pair of reeds 12 in the Z-axis guiding mechanism undergoes elastic deformation, causing a slight tilt or bend in the Z-axis. This causes a slight change X1 in the X direction as the probe moves along the Z direction. Therefore, the sources of coupling error can be derived as follows:

[0065]

[0066] like Figure 13 As shown in (a), movement in the X direction will cause a deviation Z1 in the Z direction, such as Figure 13 As shown in (b), movement in the Y direction will cause a deviation Z2 in the Z direction, such as Figure 13 As shown in (c), movement in the Z direction will cause a deviation X1 in the X direction. There is no coupling error in the Y direction, so the measured value is the true value. Only error compensation is needed in the X and Z directions. The coupling errors Z1, Z2, and X1 are then solved:

[0067]

[0068]

[0069]

[0070] In the formula, x, y, and z are the original values ​​of the input signal, x1 is the coupling error component of the Z-axis displacement to the X-axis displacement, z1 is the coupling error component of the X-axis displacement to the Z-axis displacement, z2 is the coupling error component of the Y-axis displacement to the X-axis displacement, and H represents the length of the reed.

[0071] True value determination after error compensation:

[0072]

[0073]

[0074]

[0075] In the formula, x 真 y 真z 真 These represent the true values ​​after error compensation.

[0076] Error compensation algorithm logic block diagram, as follows Figure 14 As shown, the three-dimensional raw displacement signals X, Y, and Z output by the four-quadrant detector contain coupling error components. The coupling error calculation module calculates the coupling errors x1, z1, and z2 of each axis. The least squares decoupling module separates the coupling errors of each axis. Then, the true value correction module compensates for the measured values ​​in real time, outputs the true value, and transmits the data to the host computer, realizing a three-dimensional measurement system that is closer to complete decoupling, thereby improving the overall accuracy and reliability of the probe.

[0077] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A low-coupling contact scanning probe device based on a parallel reed assembly, characterized in that, Includes a probe protection device, a triaxial flexible guide mechanism and a displacement detection system (9); The triaxial flexible guide mechanism is set inside the probe housing (1) of the probe protection device and the two are detachably connected; the displacement detection system (9) is set inside the probe housing (1) and is respectively installed on the probe housing (1) and the triaxial flexible guide mechanism; The triaxial flexible guide mechanism includes a probe (5), an XZ-axis guide mechanism (7), and a Y-axis guide mechanism (8); the XZ-axis guide mechanism (7) and the Y-axis guide mechanism (8) are orthogonally nested; the lower end face of the Y-axis guide mechanism (8) is fixedly connected to the probe (5); The XZ axial guide mechanism (7) includes an X-axis guide mechanism, a Z-axis guide mechanism, and a gravity balance device spring (11); the X-axis guide mechanism is nested and fixed inside the Z-axis guide mechanism, and the two ends of the gravity balance device spring (11) are fixedly connected to one end of the X-axis guide mechanism and one end of the Z-axis guide mechanism, respectively. The X-axis guiding mechanism includes a pair of springs (2), an X-axis fixed plate (701), and an X-axis translational plate (702); the X-axis fixed plate (701) and the X-axis translational plate (702) are both horizontal and directly opposite each other, and the pair of springs (2) are fixedly connected to the left and right sides of the X-axis fixed plate (701) and the X-axis translational plate (702); The Z-axis guiding mechanism includes a pair of spring plates (12), a Z-axis fixed plate (703), and a Z-axis translational plate (704); the Z-axis fixed plate (703) and the Z-axis translational plate (704) are both vertical and arranged facing each other, and the pair of spring plates (12) are fixedly connected to the upper and lower ends of the Z-axis fixed plate (703) and the Z-axis translational plate (704); a partition plate (705) is horizontally arranged on the left side of the Z-axis translational plate (704); there is a gap between the partition plate (705) and the Z-axis fixed plate (703); The X-axis translation plate (702) has a long strip-shaped through hole in the center, through which the Z-axis guide mechanism can pass. The Z-axis guide mechanism passes through the long strip-shaped through hole, and the Z-axis fixing plate (703) is fixedly connected to the left side of the inner wall of the long strip-shaped through hole. There is a gap between the Z-axis translation plate (704) and the long strip-shaped through hole. The two ends of the spring (11) of the gravity balancing device are fixedly connected to the lower end face of the X-axis fixed plate (701) and the upper end face of the Z-axis translation plate (704); The Y-axis guiding mechanism (8) includes a pair of spring sheets (13), a Y-axis fixing plate (801), and a probe base (10); the upper end face of the Y-axis fixing plate (801) is fixedly connected to the lower end face of the spacer plate (705), the Y-axis fixing plate (801) and the probe base (10) are both horizontal and directly opposite each other, and the pair of spring sheets (13) are fixedly connected to the front and rear sides of the Y-axis fixing plate (801) and the probe base (10); The probe (5) is fixedly connected to the center of the lower end face of the probe base (10).

2. The low-coupling contact scanning probe device based on a parallel reed group according to claim 1, characterized in that, The probe protection device includes a probe housing (1) and a mounting handle (3); one end of the probe housing (1) is closed and the other end is open, and the closed end of the probe housing (1) is provided with a mounting handle (3); the X-axis fixing plate (701) is detachably connected to the closed end of the probe housing (1).

3. The low-coupling contact scanning probe device based on a parallel reed group according to claim 1, characterized in that, The displacement detection system (9) includes a laser (901), a bias beam splitter (903), and two quadrant detectors (905). The laser (901) is fixed inside the probe housing (1) by a laser adjustment seat (902). The bias beam splitter (903) is fixed inside the probe housing (1) by a beam splitter adjustment seat (904) and is positioned on the emission path of the laser (901). The two quadrant detectors (905) are respectively positioned horizontally and vertically and are fixedly connected to the upper end face of the probe base (10). The bias beam splitter (903) splits the incident beam into two paths, namely a horizontal optical path and a vertical optical path. The horizontally positioned quadrant detector (905) is positioned on the vertical optical path of the bias beam splitter (903), and the vertically positioned quadrant detector (905) is positioned on the horizontal optical path of the bias beam splitter (903).

4. The low-coupling contact scanning probe device based on a parallel reed group according to claim 1, characterized in that, The pair of springs 1 (2), 2 (12) and 3 (13) are all the same in shape and size, and are covered by clamps (14) on both sides; all the springs are made of beryllium bronze; the clamps (14) are made of silicon carbide aluminum alloy.

5. The low-coupling contact scanning probe device based on a parallel reed group according to claim 1, characterized in that, The upper and lower ends of the gravity balancing device spring (11) are respectively fixed with threaded columns. The lower end face of the X-axis fixed plate (701) and the upper end face of the Z-axis translation plate (704) are provided with threaded holes in opposite positions. The threaded column at the upper end of the gravity balancing device spring (11) is threadedly engaged with the threaded hole at the lower end face of the X-axis fixed plate (701), and the threaded column at the lower end of the gravity balancing device spring (11) is threadedly engaged with the threaded hole at the upper end face of the Z-axis translation plate (704).

6. The low-coupling contact scanning probe device based on a parallel reed group according to claim 3, characterized in that, The laser (901) emission path and the two optical paths after the beam is split by the bias beam splitter (903) coincide with the spatial axes of the X-axis, Y-axis and Z-axis.

7. The low-coupling contact scanning probe device based on a parallel reed group according to claim 3, characterized in that, A horizontally positioned four-quadrant detector (905) is used to detect the X / Y axis spot displacement; A vertically positioned four-quadrant detector (905) is used to detect the Z-axis light spot displacement, and the light spot displacement is converted into a three-dimensional voltage signal output through photoelectric conversion.

8. The low-coupling contact scanning probe device based on a parallel reed group according to claim 7, characterized in that, The scanning probe device also includes a closed-loop feedback coupling error compensation module, the input of which is connected to the output of the four-quadrant detector (905). The closed-loop feedback coupling error compensation module is used to process the original three-dimensional voltage signal output by the four-quadrant detector (905), and then separates each axial coupling component in real time by the least squares method, and performs dynamic compensation by the truth value correction module, and finally outputs the displacement truth value that is close to complete decoupling.

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