Low-coupling contact type scanning probe device based on parallel reed group

Abstract

The invention provides a low-coupling contact type scanning probe device based on a parallel reed group, and belongs to the technical field of precision measurement. The device comprises a measuring head protection device, a three-axis flexible guide mechanism and a displacement detection system. The three-axis flexible guide mechanism adopts three pairs of parallel reed groups which are connected in series through a fixed plate and a translational plate to form an X / Y / Z three-axis independent movement low-coupling guide mechanism, and a gravity balance device spring is combined to counteract the Z-direction self-weight influence, so that the cross coupling error is reduced, and the reset precision and the dynamic response are improved. The displacement detection system is based on a single laser and a bias beam splitter prism, light beams are distributed to a horizontal four-quadrant detector and a vertical four-quadrant detector, three-dimensional displacement signals are captured synchronously, Abbe errors are eliminated, a closed-loop feedback coupling error compensation module is integrated, and residual coupling errors are corrected in real time through a least square method. The problems that an elastic element is prone to fatigue, uneven in rigidity in all directions, poor in dynamic performance and high in cost are solved, and the advantages of being high in precision, long in service life and low in cost are achieved.

Description

Technical Field

[0001] The invention relates to a low-coupling contact scanning probe device based on a parallel spring group, belonging to the technical field of precision measurement. Background Art

[0002] As a key component of precision measuring instruments, 3D probes play a vital role in high-precision measurement equipment such as coordinate measuring machines (CMMs) and gear measuring centers. Their accuracy and performance directly determine the precision and efficiency of the entire measurement system. With the rapid advancement of precision measurement technology, the accuracy requirements and comprehensive mechanical performance standards for 3D probes are becoming increasingly stringent. Currently, research in this field focuses on optimizing the structural guidance mechanisms of the three coordinate axes and improving the overall performance of the probe system. Compared to touch-trigger probes, scanning probes, also known as linear probes, effectively address technical challenges such as anisotropy, pre-travel error, and sampling point limitations through innovative probe structural design and measurement methods. The core technology of this type of probe lies in a frictionless, zero-backlash error, and highly sensitive micro-displacement system that ensures output proportional to stylus deflection. It also offers the multi-functionality of precisely locating spatial coordinate points and efficiently scanning curves and surfaces. This design not only improves measurement accuracy and efficiency, but also provides a more reliable solution for measuring complex workpieces.

[0003] Traditional contact scanning probes often suffer from the following structural design issues: 1. Elastic elements are prone to fatigue deformation, resulting in reduced reset accuracy; 2. Inconsistent isotropic stiffness affects measurement stability; 3. Complex structure and high manufacturing cost; 4. Poor dynamic response characteristics, making them difficult to adapt to high-speed scanning measurement. For example, among foreign products, the Renishaw SP80 probe, while utilizing a nested reed structure, suffers from anisotropy and difficulty in installation and commissioning; the Zeiss VAST probe, while offering excellent dynamic performance, suffers from insufficient Z-axis sensitivity; and the Klingelnberg K3D probe has a complex mechanical structure and high manufacturing cost. Regarding domestic technology, the nested double-reed structure probe developed by Zhang Guoxiong's team at Tianjin University, while compact, suffers from issues such as error transmission and inconsistent dynamic characteristics. Currently, scanning probes produced by Harbin Measuring Tool and Cutting Tool Group Co., Ltd. mostly utilize inductive sensors, which suffer from disadvantages such as low frequency response, unsuitability for fast dynamic applications, complex conversion circuitry, and zero-position errors. In addition, the German Zeiss company's patent US4660296 discloses a three-story parallel spring three-dimensional probe guide mechanism. Although it has a simple structure and is easy to install and debug, its longitudinal dimensions are too large, and the moving parts on each layer have different masses, making it difficult to consistent the dynamic characteristics of each guiding direction. In the German Ertl patent US5029398, he proposed a three-dimensional probe guide mechanism composed of parallel springs and flexible hinges in a certain method. Although the axial motions can be decoupled, this probe structure is relatively complex and requires high manufacturing, assembly, and debugging precision, resulting in a high manufacturing cost.

[0004] In summary, there is often a conflict between simple probe structure and high-precision measurement. To achieve complete decoupling of the three-axis guide mechanism, hinges or other flexible structures must be introduced as decoupling components, or a more complex parallel structure with separate displacement detection systems for each axis must be adopted, which can also introduce Abbe errors. The present invention utilizes three pairs of orthogonally nested parallel springs, an integrated photoelectric detection system, and a dynamic error compensation algorithm. This simple structure is easy to manufacture and assemble, achieving nearly fully decoupled three-dimensional micro-displacement measurement. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem in the prior art that there is a conflict between a simple probe structure and high measurement accuracy, and to provide a low-coupling contact scanning probe device based on a parallel spring group.

[0006] The purpose of the present invention is achieved through the following technical solutions: A low-coupling contact scanning probe device based on a parallel spring group, comprising a probe protection device, a three-axis flexible guide mechanism and a displacement detection system; The three-axis flexible guide mechanism is arranged in the probe housing of the probe protection device and the two are detachably connected; the displacement detection system is arranged in the side head housing and is respectively installed on the probe housing and the three-axis flexible guide mechanism; The three-axis flexible guide mechanism includes a probe, an XZ axial guide mechanism and a Y axial guide mechanism; the XZ axial guide mechanism and the Y axial guide mechanism are orthogonally nested; the lower end surface of the Y axial guide mechanism is fixedly connected to the probe; The XZ axial guide mechanism includes an X-axial guide mechanism, a Z-axial guide mechanism and a gravity balance device spring; the X-axial guide mechanism is nested and fixed with the Z-axial guide mechanism, and the two ends of the gravity balance device spring are respectively fixedly connected to one end of the X-axial guide mechanism and the Z-axial guide mechanism.

[0007] Preferably, the X-axis guide mechanism includes a pair of springs, an X-axis fixed plate, and an X-axis translation plate; the X-axis fixed plate and the X-axis translation plate are both horizontal and arranged vertically 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 translation plate; The Z-axis guide mechanism includes a pair of second springs, a Z-axis fixed plate, and a Z-axis translation plate; the Z-axis fixed plate and the Z-axis translation plate are both vertically arranged and opposite each other, and the pair of second springs are fixedly connected to the upper and lower ends of the Z-axis fixed plate and the Z-axis translation plate; a spacer is horizontally arranged on the left side of the Z-axis translation plate; there is a gap between the spacer and the Z-axis fixed plate; A long strip through hole is provided in the center of the X-axis translation plate so that the Z-axis guide mechanism can pass through it. The Z-axis guide mechanism passes through the long strip through hole, and the Z-axis fixed plate is fixedly connected to the left side of the inner wall of the long strip through hole. There is a gap between the Z-axis translation plate and the long strip through hole. The two ends of the gravity balance device spring are fixedly connected to the lower end surface of the X-axis fixed plate and the upper end surface of the Z-axis translation plate; The Y-axis guide mechanism includes a pair of springs (three), a Y-axis fixing plate, and a probe base; the upper end surface of the Y-axis fixing plate is fixedly connected to the lower end surface of the spacer plate, the Y-axis fixing plate and the probe base are both horizontal and arranged vertically opposite each other, and a pair of springs (three) are fixedly connected to the front and rear sides of the Y-axis fixing plate and the probe base; The probe is fixedly connected to the center of the lower end surface of the probe base.

[0008] Preferably, the probe protection device includes a probe housing and a mounting handle; the probe housing is closed at one end and open at the other end, and the closed end of the probe housing is provided with a mounting handle; the X-axial fixing plate is detachably connected to the closed end of the probe housing.

[0009] Preferably, the displacement detection system includes a laser, a biased beam splitter prism and two four-quadrant detectors; the laser is fixed in the probe housing through a laser adjustment seat; the biased beam splitter prism is fixed in the probe housing through a beam splitter prism adjustment seat, and the biased beam splitter prism is arranged on the emission light path of the laser; the two four-quadrant detectors are respectively arranged horizontally and vertically and are fixedly connected to the upper end face of the probe base; the biased beam splitter prism divides the incident light beam into two paths, namely a horizontal light path and a vertical light path, wherein the horizontally arranged four-quadrant detector is arranged on the vertical light path of the biased beam splitter prism, and the vertically arranged four-quadrant detector is arranged on the horizontal light path of the biased beam splitter prism.

[0010] Preferably, the pair of reeds one, the pair of reeds two and the pair of reeds three are of the same shape and size, and are wrapped with splints on both sides; the material of all the above reeds is beryllium bronze; the material of the splint is silicon carbide aluminum alloy.

[0011] Preferably, the upper and lower ends of the gravity balancing device spring are respectively fixed with threaded columns, and the lower end surface of the X-axial fixed plate and the upper end surface of the Z-axial translation plate are provided with threaded holes in opposite positions. The upper end threaded column of the gravity balancing device spring is threadedly matched with the threaded hole on the lower end surface of the X-axial fixed plate, and the lower end threaded column of the gravity balancing device spring is threadedly matched with the threaded hole on the upper end surface of the Z-axial translation plate.

[0012] Preferably, the laser emission light path and the two light paths after being split by the biased beam splitter prism coincide with the X-axis, Y-axis and Z-axis spatial axes.

[0013] Preferably, a horizontally arranged four-quadrant detector is used to detect the X / Y axial light spot displacement; The vertically arranged four-quadrant detector is used to detect the Z-axis light spot displacement, and the light spot displacement is photoelectrically converted into a three-dimensional voltage signal output.

[0014] Preferably, the scanning probe device further comprises a closed-loop feedback coupling error compensation module, the input end of the closed-loop feedback coupling error compensation module being signal-connected to the output end of the four-quadrant detector; The closed-loop feedback coupling error compensation module is used to process the original three-dimensional voltage signal output by the four-quadrant detector, then separate the axial coupling components in real time through the least squares method, and use the true value correction module to perform dynamic compensation, ultimately outputting a displacement true value that is close to completely decoupled.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention employs three pairs of parallel leaf springs of identical shape and size as the stylus's guide mechanism. This ingeniously constructs a planar translation plate that moves together with the stylus base, creating a "coplanar" structure. This allows the stylus base to move in any direction as a translational motion, minimizing Abbe errors within the plane and effectively improving the accuracy of the stylus assembly.

[0016] 2. In the present invention, three pairs of parallel spring groups are connected in series through intermediate components, such as a translation plate and a fixed plate. Each axial motion is independent of each other, significantly reducing cross-coupling errors. The design of the clamping plate improves the rigidity of the guide mechanism while maintaining high sensitivity without increasing the number of springs.

[0017] 3. The present invention adopts a symmetrical nested structure layout of three pairs of parallel spring groups, which transmit motion through the elastic deformation of the springs themselves. The installation direction of each pair of parallel spring groups is orthogonal to the direction of freedom of motion (for example, the parallel spring group in the X-axis guide mechanism will constrain the Y / Z-axis displacement), forming a multi-directional elastic support, eliminating the microscopic clearance caused by mechanical contact in traditional hinge structures. The rotation of traditional hinges depends on the fit between the shaft and the hole, while the springs achieve equivalent rotation through bending deformation without shaft-hole gap. Therefore, the present invention is simple and compact, with a small size and light weight. There is no shaft-hole gap and no friction during the movement process, avoiding the shortcomings of traditional scanning probes that are complex in structure and inconvenient to use. At the same time, the spring structure acts as a flexible unit with good recovery performance, which greatly extends the service life of the probe under the same measurement conditions and reduces production costs.

[0018] 4. This invention uses a displacement detection system with an integrated design of a single light source and dual detectors to eliminate multi-sensor installation errors and avoid Abbe errors introduced by the misalignment of the optical path with the spatial axes of the measurement axes X, Y, and Z. Displacement in three dimensions is detected synchronously by the same optical system, simplifying the structure and improving system consistency.

[0019] 5. Aiming at the coupling error caused by the mechanical structure, the present invention proposes a closed-loop feedback coupling error compensation algorithm to compensate the measured value in real time, thus realizing a three-dimensional measurement system that is closer to complete decoupling, thereby improving the overall accuracy and reliability of the probe.

[0020] 6. Through the collaborative design of the reed's flexible guidance and the photoelectric detection in the displacement detection system, the present invention achieves a 1:1 linear relationship between the reed's deformation and the light spot offset. This significantly reduces system complexity while ensuring measurement accuracy, and solves the problems of traditional probe elastic elements such as easy fatigue, uneven stiffness in all directions, poor dynamic performance, and high cost. The present invention is suitable for high-precision scenarios such as precision machining, three-dimensional coordinate measurement, high-speed scanning, and micro-nano manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the external structure of the low-coupling contact scanning probe device based on the parallel spring group of the present invention.

[0022] Figure 2 It is a structural schematic diagram of the three-axis flexible guide mechanism of the present invention.

[0023] Figure 3 It is a schematic diagram of the top view of the three-axis flexible guide mechanism of the present invention.

[0024] Figure 4 It is a schematic structural diagram of the XZ axial guide mechanism of the present invention.

[0025] Figure 5 It is a left-side structural schematic diagram of the three-axis flexible guide mechanism of the present invention.

[0026] Figure 6 for Figure 5 An enlarged schematic diagram of the C-section structure.

[0027] Figure 7 It is a right view structural schematic diagram of the three-axis flexible guide mechanism of the present invention.

[0028] Figure 8 for Figure 7 AA cross-sectional view.

[0029] Figure 9 This is a schematic diagram of the main structure of the three-axis flexible guide mechanism of the present invention.

[0030] Figure 10 for Figure 9 BB cross-sectional view.

[0031] Figure 11 Schematic diagram of the displacement detection system structure of the present invention.

[0032] Figure 12 Schematic diagram of the spring structure of the gravity balance device.

[0033] Figure 13 Schematic diagram of the coupling error source of the present invention; wherein, Figure 13 (a) Schematic diagram of the source of X-guided coupling error; Figure 13 (b) Schematic diagram of the source of Y-guide coupling error; Figure 13 (c) Schematic diagram of the source of Z-guide coupling error.

[0034] Figure 14 This is a logic block diagram of the error compensation algorithm of the present invention.

[0035] The reference numerals in the figure are: 1 for the probe housing; 2 for a pair of springs one; 3 for the mounting handle; 4 for the fastening screw; 5 for the probe; 6 for the threaded hole; 7 for the XZ axial guide mechanism; 701 for the X-axial fixed plate; 702 for the X-axial translation plate; 703 for the Z-axial fixed plate; 704 for the Z-axial translation plate; 705 for the spacer plate; 8 for the Y-axial guide mechanism; 801 for the Y-axial fixed plate; 9 for the displacement detection system; 901 for the laser; 902 for the laser adjustment seat; 903 for the biased beam splitter prism; 904 for the beam splitter prism adjustment seat; 905 for the four-quadrant detector; 10 for the probe base; 11 for the gravity balance device spring; 12 for a pair of springs two; 13 for a pair of springs three 13; 14 for the clamping plate; and 15 for the pressure plate. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method is given, but the protection scope of the present invention is not limited to the following embodiments. Specific implementation method one: The present invention provides a low-coupling contact scanning probe device based on a parallel spring group, as shown in FIG. Figure 1 As shown, it includes a probe protection device, a three-axis flexible guide mechanism and a displacement detection system 9; the entire three-axis flexible guide mechanism is arranged in the probe housing 1 of the probe protection device, is protected by the probe housing 1 and the two are detachably connected; the probe protection device includes the probe housing 1 and a mounting handle 3; the probe housing 1 is closed at one end and open at the other end, and the closed end of the probe housing 1 is provided with a mounting handle 3; it facilitates the installation and use of the scanning probe device.

[0038] like Figure 2 As shown, the three-axis flexible guide mechanism includes a probe 5, an XZ axial guide mechanism 7 and a Y axial guide mechanism 8; the XZ axial guide mechanism 7 and the Y axial guide mechanism 8 are orthogonally nested; the lower end surface of the Y axial guide mechanism 8 is fixedly connected to the probe 5; the XZ axial guide mechanism 7 is as shown Figure 4 As shown, the XZ axial guide mechanism 7 includes an X-axial guide mechanism, a Z-axial guide mechanism and a gravity balance device spring 11; the X-axial guide mechanism is nested and fixed with the Z-axial guide mechanism, and the two ends of the gravity balance device spring 11 are fixedly connected to the X-axial guide mechanism and the Z-axial guide mechanism respectively.

[0039] The X-axis guide mechanism includes a pair of springs 2, an X-axis fixed plate 701 and an X-axis translation 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 a fastening screw 4, such as Figure 3As shown, the X-axis fixing plate 701 is provided with six threaded holes 6. The probe housing 1 is threadedly connected to the threaded holes 6 on the X-axis fixing plate 701 via set screws 4, thereby securing the probe housing 1 to the X-axis fixing plate 701. This serves as the reference mounting surface for the entire device. The X-axis fixing plate 701 and the X-axis translation plate 702 are both horizontally positioned and vertically opposed. A pair of springs 1-2 are fixedly connected to the left and right sides of the X-axis fixing plate 701 and the X-axis translation plate 702. The pair of springs 1-2 are of identical shape and size, and are wrapped on both sides with clamping plates 14 to enhance rigidity. The clamping plates 14 are fixed to the springs via adhesive bonding. The thickness of the clamping plates 14 is optimized based on the deformation requirements of the springs to ensure the accuracy of the X-axis linear guidance. A pair of springs 1-2 are fixedly connected to the left and right sides of the X-axis fixed plate 701 and the X-axis translation plate 702 via screws. Alternatively, adhesive is applied to both ends of the springs, with one side of the springs fixedly connected to the pressure plate 15 via adhesive, and the other side of the springs fixedly connected to the left and right sides of the X-axis fixed plate 701 and the X-axis translation plate 702 via adhesive, thereby forming an X-axis flexible structure. When the probe 5 is subjected to external force, the X-axis translation plate 702 undergoes micro-displacement due to the elastic deformation of the pair of springs 1-2, forming an X-axis guide mechanism.

[0040] like Figure 7 and Figure 8 As shown, the Z-axial guide mechanism includes a pair of spring leaves 12, a Z-axial fixed plate 703 and a Z-axial translation plate 704; the Z-axial fixed plate 703 and the Z-axial translation plate 704 are both vertically and arranged opposite to each other on the left and right, and a pair of spring leaves 12 are fixedly connected to the upper and lower ends of the Z-axial fixed plate 703 and the Z-axial translation plate 704; a spacer plate 705 is horizontally arranged on the left side of the Z-axial translation plate 704; there is a gap between the spacer plate 705 and the Z-axial fixed plate 703; a long strip through hole is opened in the center of the X-axial translation plate 702 to allow the Z-axial guide mechanism to pass through, the Z-axial guide mechanism passes through the long strip through hole, and the Z-axial fixed plate 703 is fixedly connected to the left side of the inner wall of the long strip through hole by gluing, and there is a gap between the Z-axial translation plate 704 and the long strip through hole; the Z-axial translation plate 704 and the X-axial translation plate 702 are not in direct contact, leaving a certain amount of space for movement. The two springs in a pair of springs 12 are of the same shape and size. Both sides of each spring are wrapped with a clamping plate 14 to improve the bending stiffness. The two ends of the gravity balance device spring 11 are fixedly connected to the lower end surface of the X-axis fixed plate 701 and the upper end surface of the Z-axis translation plate 704. Figure 12As shown, the upper and lower ends of the gravity balancing device spring 11 are respectively provided with threaded columns, and the lower end surface of the X-axial fixing plate 701 and the upper end surface of the Z-axial translation plate 704 are provided with threaded holes in opposite positions. When installing the gravity balancing device spring 11, the upper threaded column of the gravity balancing device spring 11 is first threadedly engaged with the threaded hole on the lower end surface of the X-axial fixing plate 701, and then the lower threaded column of the gravity balancing device spring 11 is threadedly engaged with the threaded hole on the upper end surface of the Z-axial translation plate 704. Threaded holes are also provided at relative positions on a pair of spring leaves 2 12 and a pressure plate 15 on the upper side of the Z-axial translation plate 704. The gravity balancing device spring 11 passes through a pair of spring leaves 2 12 and a pressure plate 15 and is threadedly engaged with the threaded hole on the upper end surface of the Z-axial translation plate 704. The threaded holes on the X-axial fixing plate 701 and the Z-axial translation plate 704 have a certain processing allowance. The compression amount of the installed gravity balancing device spring 11 is changed by screwing in / out the threads, thereby realizing the adjustment of the preload force to ensure the linearity of the Z-axial displacement detection.

[0041] like Figure 9 and Figure 10 As shown, a pair of second springs 12 are fixedly connected to the upper and lower ends of the Z-axis fixed plate 703 and the Z-axis translation plate 704 via screws. Alternatively, adhesive is applied to both ends of the springs, with one side of the springs fixedly connected to the pressure plate 15 by adhesive, and the other side of the springs fixedly connected to the upper and lower ends of the Z-axis fixed plate 703 and the Z-axis translation plate 704 by adhesive, thereby forming a Z-axis flexible structure. When the probe 5 is subjected to external force, the Z-axis translation plate 704 produces a micro-displacement due to the elastic deformation of the pair of second springs 12, forming a Z-axis guide mechanism.

[0042] The Y-axis guide mechanism is as follows Figure 5 and Figure 6As shown, the Y-axis guide mechanism 8 includes a pair of springs (three) 13, a Y-axis fixing plate 801, and a probe base 10. The upper end surface of the Y-axis fixing plate 801 is fixedly connected to the lower end surface of the spacer plate 705. The Y-axis fixing plate 801 and the probe base 10 are both horizontal and vertically opposed. The pair of springs (three) 13 are fixedly connected to the Y-axis fixing plate 801 and the front and rear sides of the probe base 10. The probe 5 is fixed to the center of the lower end surface of the probe base 10 via a threaded connection. The springs are used to contact the workpiece being measured and transmit three-dimensional displacement. The two springs in the pair of springs (three) 13 are of identical shape and size. Each spring is wrapped with a clamping plate 14 on both sides to optimize Y-axis stiffness and increase bending rigidity. Each reed is secured to the Y-axis fixing plate 801 and the front and rear sides of the probe base 10 with screws at both ends, or adhesive is applied to both sides of the reed. One side of the reed is adhesively bonded to the pressure plate 15, while the other side is adhesively bonded to the Y-axis fixing plate 801 and the front and rear sides of the probe base 10, thereby forming a flexible Y-axis structure. When the probe 5 is subjected to external force, the probe base 10 generates micro-displacement through the elastic deformation of the pair of reeds 13, forming a Y-axis guide mechanism.

[0043] Three pairs of parallel spring groups: a pair of springs 1 2, a pair of springs 2 12 and a pair of springs 3 13 are connected in series through intermediate components, such as a translation plate and a fixed plate, so that all axial movements are translational movements, which significantly reduces cross-coupling errors. The design of the clamping plate 14 improves the rigidity of the guide mechanism while maintaining high sensitivity without increasing the number of springs. The specific working process is as follows: the three pairs of parallel spring groups control independent movements in three directions respectively. When the probe 5 measures an object, only the springs play a flexible guiding role, and the other connecting parts are rigid connections; the X-axial fixed plate 701 is fixedly connected to the probe housing 1 by a fastening screw 4. When the probe 5 moves along the X-direction, the X-axial fixed plate 701 serves as a fixed support, and the X-axial translation plate 702 drives a pair of springs 1 2 to achieve X-axial guidance, while the displacement in the Y and Z directions does not change; in the Z-axial guide mechanism, the outer wall of the Z-axial fixed plate 703 is fixedly connected to the inner wall on the left side of the rectangular through hole of the X-axial translation plate 702. When the probe 5 moves along the Z direction When the probe 5 moves in the Y direction, the Z-axis fixed plate 703 serves as a fixed support, and the Z-axis translation plate 704 drives a pair of springs 12 to achieve Z-axis guidance, while the displacements in the X and Y directions remain unchanged; the Y-axis fixed plate 801 is fixed to the Z-axis translation plate 704 by gluing. When the probe 5 moves in the Y direction, the Y-axis fixed plate 801 and its connecting parts act as rigid parts, and the probe base 10 drives a pair of springs 13 to achieve Y-axis guidance, while the displacements in the X and Z directions remain unchanged; after 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 size of the probe, and on the other hand, it realizes multi-dimensional measurement and expands the scope of application.

[0044] In this embodiment, all the reeds are made of beryllium copper, which has the characteristics of high elastic modulus and high fatigue resistance. The reeds are connected in series with the fixed plate through the intermediate translation plate, which can ensure that all axial movements are translational, thereby reducing the impact of coupling errors on measurement accuracy.

[0045] In this embodiment, all the 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 reed to enhance the stiffness of the reed and ensure the linear guiding function of the reed.

[0046] like Figure 11 As shown, the displacement detection system 9 achieves high-precision capture of three-dimensional displacement signals based on the principle of laser collimation. The laser 901 is fixed to the probe housing 1 via a laser adjustment base 902 and emits a collimated laser beam. The biased beam splitter prism 903 is arranged on the emission light path of the laser 901. The biased beam splitter prism 903 splits the incident light beam into two paths, namely a horizontal light path and a vertical light path. The emission light path of the laser 901 and the two light paths after the beam splitting by the biased beam splitter prism 903 coincide with the spatial axes of the X-axis, Y-axis, and Z-axis. The horizontally arranged four-quadrant detector 905 is arranged on the vertical light path of the biased beam splitter prism 903, and the vertically arranged four-quadrant detector 905 is arranged on the horizontal light path of the biased beam splitter prism 903. Therefore, the two light paths after the beam splitting by the biased beam splitter prism 903 are respectively projected onto the two four-quadrant detectors 905 placed horizontally and vertically. The horizontally placed four-quadrant detector 905 is used to detect displacement signals in the X and Y directions. When the probe 5 is subjected to external force, causing the spring to deform in the X / Y axis, the probe base 10 drives the four-quadrant detector 905 to deflect, and the light spot moves along the X / Y axis on the surface of the four-quadrant detector 905. The vertically placed four-quadrant detector 905 is used to detect the displacement signal in the Z direction. When the Z axis is deformed, the light spot moves along the Z axis of the detector. The optical path of the laser 901 and the biased beam splitter prism 903 coincides with the measurement direction of the X / Y / Z three-axis spatial axis. The optical path of the displacement detection system 9 of the present invention is fixed. When the low-coupling contact scanning probe device based on the parallel spring group is in operation, the position of the four-quadrant detector will change along the X / Y / Z axis. However, no matter in 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.

[0047] The scanning probe device also includes a closed-loop feedback coupling error compensation module, the input end of which is connected to the output end signal 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 separate the axial coupling components in real time through the least squares method, and use the true value correction module to perform dynamic compensation, and finally output a displacement true value that is close to completely decoupled.

[0048] Coupling error sources such as Figure 13 As shown, the X / Y / Z axial deviation is mainly caused by the flexible guiding effect of the three sets of parallel reeds. Although the reeds have a good linear guiding effect, when the probe 5 is subjected to force in the X direction, a pair of reeds 1 and 2 in the X-axis guide mechanism undergo elastic deformation, causing the X-axis reeds to tilt or bend slightly. As the probe 5 moves in the X direction, a small change Z1 in the Z direction occurs. When the probe 5 is subjected to force in the Y direction, a pair of reeds 3 and 13 in the Y-axis guide mechanism 8 undergo elastic deformation, causing the Y-axis reeds to tilt or bend slightly. As the stylus moves in the Y direction, a small change Z2 in the Z direction occurs. When the stylus is subjected to force in the Z direction, a pair of reeds 2 and 12 in the Z-axis guide mechanism undergo elastic deformation, causing the Z-axis reeds to tilt or bend slightly. As the stylus moves in the Z direction, a small change X1 in the X direction occurs. The sources of coupling error can be obtained as follows: like Figure 13 As shown in (a), the movement in the X direction will cause a deviation Z1 in the Z direction, as shown in Figure 13 As shown in (b), the movement in the Y direction will cause a deviation Z2 in the Z direction, as shown in Figure 13 As shown in (c), the 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 the errors in the X and Z directions need to be compensated. The coupling errors Z1, Z2, and X1 are solved as follows: Where, x 、 y 、 z are the original values ​​of the input signals, x 1 is the coupling error component of the Z-axis to the X-axis displacement, z 1 is the coupling error component of the X-axis to Z-axis displacement, z 2 is the coupling error component of the Y-axis to the X-axis displacement, H Represents the length of the reed.

[0049] The true value solution after error compensation: Where, x 真 、 y 真 、 z真 They represent the true value after error compensation.

[0050] Error compensation algorithm logic block diagram, such as Figure 14 As shown in the figure, the three-dimensional original displacement signal X, Y, Z output by the four-quadrant detector contains the coupling error component. The coupling error calculation module calculates the coupling error of each axis. x 1. z 1. z 2. The least squares decoupling module is used to separate the axial coupling errors, and then the measurement value is compensated in real time through the true value correction module. The true value is output and the data is transmitted to the host computer to achieve a three-dimensional measurement system that is closer to complete decoupling, thereby improving the overall accuracy and reliability of the probe.

[0051] The foregoing are merely preferred embodiments of the present invention. These embodiments are all different implementations based on the overall concept of the present invention. The scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope 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 based on the scope of protection of the claims.

Claims

1. A low-coupling contact scanning probe device based on a parallel spring group, characterized in that: It includes a probe protection device, a three-axis flexible guide mechanism and a displacement detection system (9); The three-axis flexible guide mechanism is arranged in the probe housing (1) of the probe protection device, and the two are detachably connected; the displacement detection system (9) is arranged in the side head housing (1), and is respectively mounted on the probe housing (1) and the three-axis flexible guide mechanism; The three-axis flexible guide mechanism comprises a probe (5), an XZ axial guide mechanism (7) and a Y axial guide mechanism (8); the XZ axial guide mechanism (7) and the Y axial guide mechanism (8) are orthogonally nested; the lower end surface of the Y axial guide mechanism (8) is fixedly connected to the probe (5); The XZ axial guide mechanism (7) comprises an X axial guide mechanism, a Z axial guide mechanism and a gravity balance device spring (11); the X axial guide mechanism is nested and fixed with the Z axial guide mechanism, and the two ends of the gravity balance device spring (11) are respectively fixedly connected to one end of the X axial guide mechanism and the Z axial guide mechanism.

2. The low-coupling contact scanning probe device based on a parallel reed assembly according to claim 1, characterized in that: The X-axis guide mechanism comprises a pair of springs (2), an X-axis fixed plate (701) and an X-axis translation plate (702); the X-axis fixed plate (701) and the X-axis translation plate (702) are both horizontal and arranged vertically opposite to 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 translation plate (702); The Z-axis guide mechanism comprises a pair of second springs (12), a Z-axis fixed plate (703) and a Z-axis translation plate (704); the Z-axis fixed plate (703) and the Z-axis translation plate (704) are both vertically arranged and arranged opposite to each other on the left and right sides, and the pair of second springs (12) are fixedly connected to the upper and lower ends of the Z-axis fixed plate (703) and the Z-axis translation plate (704); a spacer plate (705) is horizontally arranged on the left side of the Z-axis translation plate (704); a gap exists between the spacer plate (705) and the Z-axis fixed plate (703); A long strip through hole is provided at the center of the X-axis translation plate (702) so that the Z-axis guide mechanism can pass through the long strip through hole, and the Z-axis fixed plate (703) is fixedly connected to the left side of the inner wall of the long strip through hole, and a gap is formed between the Z-axis translation plate (704) and the long strip through hole; The two ends of the gravity balancing device spring (11) are fixedly connected to the lower end surface of the X-axis fixed plate (701) and the upper end surface of the Z-axis translation plate (704); The Y-axis guide mechanism (8) includes a pair of spring three (13), a Y-axis fixed plate (801) and a probe base (10); the upper end surface of the Y-axis fixed plate (801) is fixedly connected to the lower end surface of the spacer plate (705), the Y-axis fixed plate (801) and the probe base (10) are both horizontal and arranged vertically opposite each other, and the pair of spring three (13) is fixedly connected to the front and rear sides of the Y-axis fixed plate (801) and the probe base (10); The probe (5) is fixedly connected to the center of the lower end surface of the probe base (10).

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

4. The low-coupling contact scanning probe device based on a parallel reed assembly according to claim 2, characterized in that: The displacement detection system (9) comprises a laser (901), a biased beam splitter prism (903) and two four-quadrant detectors (905); the laser (901) is fixed in the probe housing (1) via a laser adjustment seat (902); the biased beam splitter prism (903) is fixed in the probe housing (1) via a beam splitter prism adjustment seat (904), and the biased beam splitter prism (903) is arranged on the emission light path of the laser (901); the two four-quadrant detectors (905) are respectively arranged horizontally and vertically and are both fixedly connected to the upper end surface of the probe base (10); the biased beam splitter prism (903) splits the incident light beam into two paths, namely a horizontal light path and a vertical light path, wherein the horizontally arranged four-quadrant detector (905) is arranged on the vertical light path of the biased beam splitter prism (903), and the vertically arranged four-quadrant detector (905) is arranged on the horizontal light path of the biased beam splitter prism (903).

5. The low-coupling contact scanning probe device based on a parallel reed assembly according to claim 2, characterized in that: The pair of reeds one (2), the pair of reeds two (12) and the pair of reeds three (13) are all of the same shape and size, and are all wrapped with a splint (14) on both sides; the material of all the reeds is beryllium bronze; the material of the splint (14) is silicon carbide aluminum alloy.

6. The low-coupling contact scanning probe device based on a parallel reed assembly according to claim 2, characterized in that: The upper and lower ends of the gravity balancing device spring (11) are respectively fixed with threaded columns, and the lower end surface of the X-axial fixed plate (701) and the upper end surface of the Z-axial translation plate (704) are provided with threaded holes in opposite positions. The upper end threaded column of the gravity balancing device spring (11) is threadedly engaged with the threaded hole on the lower end surface of the X-axial fixed plate (701), and the lower end threaded column of the gravity balancing device spring (11) is threadedly engaged with the threaded hole on the upper end surface of the Z-axial translation plate (704).

7. The low-coupling contact scanning probe device based on a parallel reed assembly according to claim 4, characterized in that: The emission light path of the laser (901) and the two light paths after light splitting by the biased light splitting prism (903) coincide with the X-axis, Y-axis and Z-axis spatial axes.

8. The low-coupling contact scanning probe device based on a parallel reed assembly according to claim 4, characterized in that: A horizontally arranged four-quadrant detector (905) for detecting X / Y axial light spot displacement; The vertically arranged four-quadrant detector (905) is used to detect the Z-axis light spot displacement, and the light spot displacement is photoelectrically converted into a three-dimensional voltage signal output.

9. The low-coupling contact scanning probe device based on a parallel reed assembly according to claim 8, characterized in that: The scanning probe device further comprises a closed-loop feedback coupling error compensation module, the input end of the closed-loop feedback coupling error compensation module being signal-connected to the output end 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 separate the axial coupling components in real time by the least square method, and perform dynamic compensation using the true value correction module, and finally output a displacement true value that is close to completely decoupled.

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