An active scanning device for large-depth-ratio deep hole measurement

Abstract

The application discloses an active scanning device for large-depth-diameter-ratio deep hole measurement and belongs to the technical field of precision measurement. The active scanning device comprises a displacement scanning module, a pose measurement module and a signal processing module. The displacement scanning module comprises a quantum tunneling measuring needle, a Z-direction nanometer piezoelectric driving unit and an X-Y-direction nanometer piezoelectric driving unit. The pose measurement module comprises three orthogonal umbrellas, a laser interferometer and three orthogonal reflective surface slopes. The signal processing module is used for displacement adjustment in X / Y / Z directions, three-dimensional translation movement of the quantum tunneling measuring needle, measurement and calculation of three-dimensional rotation attitude. The active scanning movement system and the six-degree-of-freedom pose measurement system are integrated in the same probe, so that the dynamic response capability and the measurement precision in the measurement process of the complex curved surface and the micro-nano structure are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of precision measurement technology, specifically relating to an active scanning device for measuring deep holes with large depth-to-diameter ratios. Background Technology

[0002] The scanning probe is a core component of a coordinate measuring machine (CMM) for achieving high-precision contour measurement and digital reconstruction of complex surfaces. Based on the different stylus support methods, scanning probes can generally be divided into two main categories: passive scanning probes and active scanning probes.

[0003] Passive scanning probes typically employ mechanical springs to support the probe and utilize displacement sensors to measure probe deflection to acquire workpiece surface contour information. To facilitate correspondence with the widely used orthogonal coordinate system in industry, most existing passive scanning probes employ a series-stacked elastic support structure in the X, Y, and Z directions, with an independent position sensor for displacement detection in each direction. This type of probe has advantages such as simple structure, mature measurement principles, and convenient data processing, and has therefore been widely used in industrial measurement for a long time. However, the mechanical stiffness, damping, and equivalent mass of a passive scanning probe are determined by the elastic mechanism itself, making dynamic adjustment difficult for different measurement tasks. In complex free-form surfaces, high-speed scanning, and the measurement of minute features, the probe can only passively follow the workpiece surface movement, easily generating dynamic tracking errors and contact force fluctuations, thus limiting further improvements in measurement speed and accuracy.

[0004] To overcome the problem of fixed mechanical characteristics in passive scanning probes, researchers have proposed active scanning probes. Compared to passive scanning probes, active scanning probes can dynamically adjust their mechanical impedance characteristics according to different measurement tasks, thereby achieving smaller contact forces, faster dynamic response, and higher scanning speeds. However, existing research on active scanning probes mainly focuses on stylus position control and contact force control, and their measurement objects are usually limited to the translational displacement information of the stylus in the X, Y, and Z directions. Most active scanning probes cannot perform real-time measurement and calculation of attitude changes such as pitch, yaw, and roll angles generated by the stylus during scanning, thus making it difficult to obtain complete six-degree-of-freedom motion state information of the stylus. When the stylus length increases, the scanning speed increases, or complex spatial curved surfaces are measured, the Abbe error, angular error, and dynamic coupling error introduced by the stylus attitude changes will significantly affect the measurement results. In addition, most existing six-degree-of-freedom measurement schemes rely on external multi-sensor systems or large interferometric measurement devices, which are not only structurally complex but also difficult to integrate into the probe, limiting their application in high-precision scanning measurements.

[0005] In summary, there is currently a lack of a novel scanning device that combines active scanning capability with six-degree-of-freedom pose measurement capability to achieve synchronous measurement and real-time calculation of probe translational motion and posture motion. Summary of the Invention

[0006] In view of this, the main objective of the present invention is to provide an active scanning device for measuring deep holes with large aspect ratios. By integrating the active scanning motion system and the six-degree-of-freedom pose measurement system into the same probe, it is possible not only to construct a high-speed closed-loop active scanning system using a quantum tunneling probe and a nanopiezoelectric drive platform, but also to acquire the six-degree-of-freedom pose information of the probe in real time by means of an integrated laser interferometry structure, and to eliminate Abbe error by converging the optical path at the probe measurement point, thereby significantly improving the dynamic response capability and measurement accuracy in the measurement process of complex curved surfaces and micro / nano structures.

[0007] To achieve the above objectives, this invention proposes an active scanning device for measuring deep holes with large aspect ratios, comprising: a displacement scanning module, including a quantum tunneling probe, a Z-axis nanopiezoelectric driving unit for adjusting the Z-direction driving displacement of the quantum tunneling probe, and an XY-axis nanopiezoelectric driving unit for adjusting the X-direction and Y-direction driving displacements of the quantum tunneling probe, wherein the quantum tunneling probe transmits displacement signals; a pose measurement module, including three orthogonal umbrellas fixed to the quantum tunneling probe and moving synchronously with it, three sets of laser interferometers uniformly distributed among the three orthogonal umbrellas, and three orthogonal reflective surface slopes located below the three orthogonal umbrellas as a stationary reflection reference, for measuring the pose change of the quantum tunneling probe, wherein the laser interferometers transmit pose signals; and a signal processing module for acquiring displacement. The signal is fed back to the Z-axis nanopiezoelectric drive unit and the XY-axis nanopiezoelectric drive unit for displacement adjustment in the X / Y / Z directions. The pose signal is acquired simultaneously to measure and calculate the three-dimensional translational motion and three-dimensional rotational attitude of the quantum tunneling probe. The XY-axis nanopiezoelectric drive unit includes a coaxially integrated X-axis nanopiezoelectric drive unit for outputting X-direction drive displacement and a Y-direction nanopiezoelectric drive unit for outputting Y-direction drive displacement. The Z-axis nanopiezoelectric drive unit carries and outputs the Z-direction drive displacement to the XY-axis nanopiezoelectric drive unit through the first output motion stage. The XY-axis nanopiezoelectric drive unit transmits the superimposed X-direction drive displacement and Y-direction drive displacement to the quantum tunneling probe through the second output motion stage. The quantum tunneling probe is fixed at the bottom of the second output motion stage.

[0008] Furthermore, the active scanning device also includes: a housing with a bottom plate having a detection hole for a quantum tunneling probe to extend out of the housing through the detection hole for active scanning of complex curved surfaces; a Z-axis nano-piezoelectric drive unit fixed inside the top plate of the housing; and a tri-orthogonal reflective surface slope fixedly installed inside the bottom plate, with the central hole of the tri-orthogonal reflective surface slope corresponding to and covering the detection hole.

[0009] Furthermore, the Z-axis nano-piezoelectric drive unit includes a first flexible hinge, a first piezoelectric actuator disposed inside the first flexible hinge, and a first output motion stage connected to the first flexible hinge; wherein, the bottom of the first output motion stage is fixedly connected to the XY-axis nano-piezoelectric drive unit; the first piezoelectric actuator provides a driving displacement in the Z direction, and the first flexible hinge adjusts the displacement and outputs the driving displacement in the Z direction through the first output motion stage.

[0010] Furthermore, the X-axis nanopiezoelectric drive unit includes an X-base mounted on one side of the bottom of the Z-axis nanopiezoelectric drive unit, an X-sensor coaxially mounted with the X-base, an X-connector fixedly connected to the X-sensor on one side and moving parallel to the X-axis, and an X-axis nanopiezoelectric drive hinge mechanism fixed on the other side of the X-connector.

[0011] Furthermore, the X-direction nano-piezoelectric drive hinge mechanism includes a pair of symmetrically arranged X flexible hinges and an X-direction nano-piezoelectric actuator arranged opposite to each other and assembled inside the X flexible hinges. The Y-direction drive displacement generated by the X-direction nano-piezoelectric actuator is converted into the X-direction through the X flexible hinges and output through the second output motion stage.

[0012] Furthermore, the Y-axis nanopiezoelectric drive unit includes a Y-base mounted on the other side of the bottom of the Z-axis nanopiezoelectric drive unit, a Y sensor coaxially mounted with the Y-base, a Y connector fixedly connected to the Y sensor on one side and moving parallel to the Y-axis, and a Y-axis nanopiezoelectric drive hinge mechanism fixed on the other side of the Y connector.

[0013] Furthermore, the Y-direction nano-piezoelectric drive hinge mechanism includes a pair of symmetrically arranged Y flexible hinges and a Y-direction nano-piezoelectric actuator arranged opposite to each other and assembled inside the Y flexible hinges. The X-direction drive displacement generated by the Y-direction nano-piezoelectric actuator is converted to the Y-direction through the Y flexible hinges and output through the second output motion stage.

[0014] Furthermore, the quantum tunneling probe includes a microsphere, a signal transmission mechanism connected to the microsphere, a shielding mechanism that wraps around the signal transmission mechanism, a mounting mechanism located at the end of the shielding mechanism, a signal connector located at the mounting mechanism and connected to the signal transmission mechanism, and a transmission cable that connects to the signal connector and transmits signals.

[0015] Furthermore, the signal processing module acquires the electrical signal of the quantum tunneling probe, converts the electrical signal into a distance error signal, and transmits the distance error signal to the Z-axis nanopiezoelectric drive unit and the XY-axis nanopiezoelectric drive unit for error closed-loop control, and performs displacement compensation adjustment in the X / Y / Z directions.

[0016] Furthermore, three sets of laser interferometers move synchronously with the quantum tunneling probe. The three sets of beams are incident on three orthogonal reflective surfaces, forming three static spatial reflection references in mutually perpendicular directions. These references are used to measure the three-dimensional translational motion and three-dimensional rotational attitude of the quantum tunneling probe. The three sets of beams converge at the measurement point of the quantum tunneling probe to eliminate Abbe error. The three-dimensional translation includes translation in the X, Y, and Z directions. The three-dimensional rotation includes rotation around the X-axis, rotation around the Y-axis, and rotation around the Z-axis.

[0017] Based on the above technical solution, it can be seen that the technical solution of the present invention has at least one of the following beneficial effects compared with the prior art:

[0018] (1) The active scanning motion system proposed in this invention features fast dynamic response and high measurement accuracy. Compared to the traditional closed-loop control loop embedded in the coordinate measuring machine body, this active scanning motion system is embedded inside the probe, resulting in a fast response speed. Compared to contact probes, the quantum tunneling probe used in this invention is a non-contact probe, offering high measurement accuracy. The active scanning motion system proposed in this invention features fast dynamic response, high measurement accuracy, and excellent tracking performance. Compared to the closed-loop control method in traditional coordinate measuring machines where the probe feedback signal is transmitted to the machine body control system for motion compensation, this invention directly integrates the active scanning control system inside the probe. The measurement signal acquired by the quantum tunneling probe does not need to undergo long-link transmission and processing through the coordinate measuring machine controller; instead, it is directly fed back to the nanopiezoelectric drive unit to form a local closed-loop control loop, thereby significantly shortening the control link length, reducing system latency, and improving control bandwidth and dynamic response speed.

[0019] (2) This invention proposes a six-DOF pose measurement system for a probe integrated into the probe head without Abbe error. By fixing a laser interferometer to the probe and forming a measurement loop with a three-orthogonal reflective umbrella set inside the housing, the system achieves synchronous measurement and real-time calculation of the probe's three-dimensional translational motion and three-dimensional rotational attitude without significantly increasing the overall volume and mass of the probe head. Compared with traditional solutions that use external pose measurement systems, multi-sensor combined measurement systems, or independent angle detection devices, this invention eliminates the need for additional complex measurement equipment outside the probe head, avoiding system structural redundancy and the introduction of multi-sensor installation and calibration errors, thereby significantly improving system integration and reliability.

[0020] (3) The high-precision active scanning device for deep hole measurement with large depth-to-diameter ratio proposed in this invention has the characteristics of compact structure and high functional integration. Compared with the existing active scanning probes that only have stylus position control and contact force control functions, this invention directly integrates the stylus six-degree-of-freedom pose measurement function into the active scanning probe, realizing the integrated design of active scanning system and pose measurement system.

[0021] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of the present invention, nor is it intended to restrict the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0023] Figure 1 This is a schematic diagram of the planar structure of the active scanning device of the present invention;

[0024] Figure 2 This is a three-dimensional perspective view of the active scanning device of the present invention;

[0025] Figure 3 This is a schematic diagram of the X-direction nanopiezoelectric driven hinge mechanism of the present invention;

[0026] Figure 4 This is a schematic diagram of the installation of the X-direction nanopiezoelectric drive unit of the present invention;

[0027] Figure 5 This is a schematic diagram of the Y-direction nanopiezoelectric driven hinge mechanism of the present invention;

[0028] Figure 6 This is a schematic diagram of the installation of the Y-direction nanopiezoelectric drive unit of the present invention;

[0029] Figure 7 This is a schematic diagram of the quantum tunneling probe of the present invention;

[0030] The diagram shows the following labels: 1, Z-axis nano-piezoelectric drive unit; 1-1, first output motion stage; 1-2, first flexible hinge; 1-3, first piezoelectric actuator; 2, XY-axis nano-piezoelectric drive unit; 2-1, X-axis nano-piezoelectric drive unit; 2-2, Y-axis nano-piezoelectric drive unit; 2-3, second output motion stage; 2-4, X-base; 2-5, X-sensor; 2-6, X-connector; 2-7, X-flexible hinge; 2-8, X-axis nano-piezoelectric actuator; 2-9, Y-base; 2-10, Y-sensor. 2-11, Y connector; 2-12, Y flexible hinge; 2-13, Y-direction nano-piezoelectric actuator; 3, tri-orthogonal umbrella; 4, laser interferometer; 5, tri-orthogonal reflective surface slope; 6, quantum tunneling probe; 6-1, micro-bulb; 6-2, signal transmission mechanism; 6-3, shielding mechanism; 6-4, mounting mechanism; 6-5, signal connector; 6-6, transmission cable; 7, housing. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of the invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0033] To achieve the above objectives, this invention proposes an active scanning device for deep hole measurement with large aspect ratios, such as... Figures 1 to 7 As shown, it includes:

[0034] The displacement scanning module includes a quantum tunneling probe 6, a Z-direction nanopiezoelectric driving unit 1 for adjusting the Z-direction driving displacement of the quantum tunneling probe 6, and an XY-direction nanopiezoelectric driving unit 2 for adjusting the X-direction driving displacement and Y-direction driving displacement of the quantum tunneling probe 6. The quantum tunneling probe 6 sends a displacement signal.

[0035] The pose measurement module includes a triorthogonal umbrella 3 fixed to the quantum tunneling probe 6 and moving synchronously with the quantum tunneling probe 6, three sets of laser interferometers 4 evenly distributed on the triorthogonal umbrella 3, and a triorthogonal reflective surface slope 5 located below the triorthogonal umbrella 3 as a stationary reflective reference, used to measure the pose change of the quantum tunneling probe 6, and the laser interferometer 5 sends the pose signal.

[0036] The signal processing module acquires displacement signals and feeds them back to the Z-axis nanopiezoelectric drive unit 1 and the XY-axis nanopiezoelectric drive unit 2 for displacement adjustment in the X / Y / Z directions. Simultaneously, it acquires pose signals to measure and calculate the three-dimensional translational motion and three-dimensional rotational attitude of the quantum tunneling probe 6.

[0037] The XY-direction nanopiezoelectric drive unit 2 includes an X-direction nanopiezoelectric drive unit 2-1 for outputting X-direction drive displacement and a Y-direction nanopiezoelectric drive unit 2-2 for outputting Y-direction drive displacement, which are coaxially integrated. The Z-direction nanopiezoelectric drive unit 1 carries and outputs Z-direction drive displacement to the XY-direction nanopiezoelectric drive unit 2 through the first output motion stage 1-1. The XY-direction nanopiezoelectric drive unit 2 transmits the X-direction drive displacement and Y-direction drive displacement to the quantum tunneling probe 6 through the second output motion stage 2-3. The quantum tunneling probe 6 is fixed at the bottom of the second output motion stage 2-3.

[0038] The aforementioned active scanning device integrates a displacement scanning module and a pose measurement module. In the displacement scanning module, a quantum tunneling probe acts as a non-contact distance sensor. Its microsphere forms a nanometer-scale tunneling gap with the measured surface, and the tunneling current changes exponentially with the gap distance, thus converting the current signal into a real-time distance feedback signal. This signal, acquired by the signal processing module, directly drives the Z-axis and XY-axis nanopiezoelectric drive units, forming a local closed-loop control circuit within the probe: the displacement scanning module enables the probe to adaptively follow the motion in three-dimensional space, completing the active scanning. In the pose measurement module, three sets of laser interferometers are uniformly distributed on the three orthogonal umbrellas fixed to the probe. Their beams are incident on the three orthogonal reflecting surface slope (stationary reflection reference) fixed at the lower end of the housing, moving synchronously with the probe. The signal processing module synchronously acquires the pose signal and calculates the three-dimensional translational and three-dimensional rotational attitude of the probe. Among them, the active scanning control system is built into the probe, eliminating the need for long-distance transmission through the coordinate machine host, significantly shortening the control delay and improving the dynamic response speed and control bandwidth; the quantum tunneling probe adopts a non-contact method, providing high measurement accuracy and maintaining a constant scanning gap to avoid contact force fluctuations; the pose measurement system is integrated inside the probe, with a compact structure, eliminating the need for multiple external sensors and avoiding installation and calibration errors; the optical paths of three sets of laser interferometers converge at the measurement point, effectively eliminating Abbe error and improving measurement accuracy.

[0039] In a preferred embodiment, such as Figure 1 and Figure 2 As shown, the active scanning device also includes: a housing 7, with a probe hole in the bottom plate for the quantum tunneling probe 6 to extend out of the housing 7 through the probe hole for active scanning of complex curved surfaces; a Z-axis nano-piezoelectric drive unit 1 is fixed inside the top plate of the housing 7, and a tri-orthogonal reflective surface slope 5 is fixedly installed inside the bottom plate, with the center hole of the tri-orthogonal reflective surface slope 5 corresponding to and covering the probe hole. The housing 7 serves as the overall mounting base, providing a closed and stable mechanical support to protect the internal precision components; the tri-orthogonal reflective surface slope 5 is fixed to the bottom plate, serving as a static reference for interferometry, forming a stable measurement loop with the follower part of the quantum tunneling probe 6; the center hole of the tri-orthogonal reflective surface slope 5 is aligned with the probe hole to ensure that the movement of the quantum tunneling probe 6 is not interfered with, making it suitable for scanning measurements of complex curved surfaces and deep holes with large aspect ratios.

[0040] In a preferred embodiment, such as Figure 1 and Figure 2As shown, the Z-axis nanopiezoelectric drive unit 1 includes a first flexible hinge 1-2, a first piezoelectric actuator 1-3 disposed inside the first flexible hinge 1-2, and a first output motion stage 1-1 connected to the first flexible hinge 1-2. The bottom of the first output motion stage 1-1 is fixedly connected to the XY-axis nanopiezoelectric drive unit 2. The first piezoelectric actuator 1-3 provides the Z-axis drive displacement, and the first flexible hinge 1-2 adjusts the displacement to output the Z-axis drive displacement through the first output motion stage 1-1. Under voltage drive, the first piezoelectric actuator 1-3 generates a micro-displacement in the Z-axis. The first flexible hinge 1-2 precisely adjusts the direction and amplitude of the drive displacement through elastic deformation, and finally, the Z-axis displacement is stably output through the first output motion stage 1-1 and transmitted to the XY-axis nanopiezoelectric drive unit 2 below. The use of a flexible hinge enables frictionless and gapless operation, achieving nanometer-level resolution displacement output with smooth and repeatable motion. The piezoelectric actuator has high-frequency response characteristics, allowing for rapid response to feedback signals and meeting the real-time adjustment requirements during high-speed scanning.

[0041] In a preferred embodiment, such as Figure 3 and Figure 4 As shown, the X-axis nanopiezoelectric drive unit 2-1 includes an X-base 2-4 mounted on one side of the bottom of the Z-axis nanopiezoelectric drive unit 1, an X-sensor 2-5 coaxially mounted with the X-base 2-4, an X-connector 2-6 fixedly connected to the X-sensor 2-5 on one side and moving parallel to the X-axis, and an X-axis nanopiezoelectric drive hinge mechanism fixed to the other side of the X-connector 2-6. The X-sensor 2-5 is used to detect the actual X-axis displacement, and the X-connector 2-6 transmits the X-axis drive displacement generated by the X-axis nanopiezoelectric drive hinge mechanism to the subsequent second output motion stage 2-3. The X-axis nanopiezoelectric drive unit 2-1 realizes independent arrangement of X-axis drive and closed-loop displacement detection, which is convenient for coaxial integration with the Y-axis nanopiezoelectric drive unit 2-2, resulting in a compact structure; the sensor is coaxially mounted with the base, reducing installation eccentricity error and improving the accuracy of displacement measurement.

[0042] In a preferred embodiment, such as Figure 3 and Figure 4 As shown, the X-direction nano-piezoelectric drive hinge mechanism includes a pair of symmetrically arranged X-flexible hinges 2-7, and an X-direction nano-piezoelectric actuator 2-8 arranged opposite to each other and assembled inside the X-flexible hinges 2-7. The Y-direction drive displacement generated by the X-direction nano-piezoelectric actuator 2-8 is converted into the X-direction displacement through the X-flexible hinges 2-7, and then output through the second output motion stage 2-3. Utilizing the motion conversion function of the X-flexible hinges 2-7, the intrinsic Y-direction motion of the X-direction nano-piezoelectric actuator 2-8 is converted into the required X-direction output without the need for an additional steering mechanism, resulting in a simple structure with no backlash. The symmetrical hinge design can counteract lateral parasitic motion, improving output straightness and repeatability.

[0043] In a preferred embodiment, such as Figure 5 and Figure 6 As shown, the Y-axis nanopiezoelectric drive unit 2-2 includes a Y-base 2-9 mounted on the other side of the bottom of the Z-axis nanopiezoelectric drive unit, a Y sensor 2-10 coaxially mounted with the Y-base 2-9, a Y connector 2-11 fixedly connected to the Y sensor 2-10 on one side and moving parallel to the Y-axis, and a Y-axis nanopiezoelectric drive hinge mechanism fixed on the other side of the Y connector 2-11. Its working principle is the same as that of the X-axis nanopiezoelectric drive unit 2-1. It is symmetrically arranged after rotating 90° with the X-axis nanopiezoelectric drive unit 2-1, together forming an XY-axis coaxial integrated platform, effectively reducing the overall volume. The coaxiality of the sensor and the base ensures detection accuracy, and the connector stably transmits the hinge displacement to the output platform, ensuring independent and controllable Y-axis movement.

[0044] In a preferred embodiment, such as Figure 5 and Figure 6 As shown, the Y-direction nanopiezoelectric drive hinge mechanism includes a pair of symmetrically arranged Y-flexible hinges 2-12 and a Y-direction nanopiezoelectric actuator 2-13 arranged opposite to each other and assembled inside the Y-flexible hinges 2-12. The X-direction drive displacement generated by the Y-direction nanopiezoelectric actuator 2-13 is converted to the Y-direction through the Y-flexible hinges 2-12, and the Y-direction drive displacement is output through the second output motion stage 2-3. The Y-direction nanopiezoelectric drive unit 2-2 achieves orthogonal conversion of the motion direction through the flexible hinges, shares the same output platform with the X-direction nanopiezoelectric drive unit 2-1, and realizes the mechanical superposition of X and Y displacements, resulting in a simple structure. The symmetrical hinges ensure smooth motion, eliminate motion coupling, and improve positioning accuracy in the XY plane.

[0045] In a preferred embodiment, such as Figure 7As shown, the quantum tunneling probe 6 includes a microsphere 6-1, a signal transmission mechanism 6-2 connected to the microsphere 6-1, a shielding mechanism 6-3 enclosing the signal transmission mechanism 6-2, a mounting mechanism 6-4 located at the end of the shielding mechanism 6-3, a signal connector 6-5 located at the mounting mechanism 6-4 and connected to the signal transmission mechanism 6-2, and a transmission cable 6-6 connecting the signal connector 6-5 and transmitting signals. The microsphere 6-1 forms a tunneling gap with the surface being measured. The tunneling current signal is transmitted through the signal transmission mechanism 6-2. The shielding mechanism 6-3 encloses the probe to suppress external electromagnetic interference. The mounting mechanism 6-4 is used to fix the probe as a whole. The signal connector 6-5 and the transmission cable 6-6 output the electrical signal to the signal processing module. The quantum tunneling probe 6 employs non-contact measurement, avoiding probe wear and contact force interference; the shielding mechanism 6-3 effectively isolates electromagnetic noise from the motor and piezoelectric actuator, ensuring that weak tunneling signals are not distorted, and providing stable measurement in complex industrial electromagnetic environments, guaranteeing accurate transmission of micro-current signals; the overall probe is slender and compact, and the micro-ball 6-1 is tiny, allowing it to penetrate into extremely small apertures, high aspect ratio blind holes, and stepped deep holes; the standardized mounting mechanism 6-4 allows for quick replacement of micro-balls of different sizes, adapting to the measurement needs of deep holes with different apertures.

[0046] In a preferred embodiment, the signal processing module acquires the electrical signal of the quantum tunneling probe 6, converts the electrical signal into a distance error signal, and transmits the distance error signal to the Z-axis nanopiezoelectric drive unit 1 and the XY-axis nanopiezoelectric drive unit 2 for error closed-loop control, performing displacement compensation adjustment in the X / Y / Z directions, so that the probe always follows the changes in the workpiece contour and maintains a constant scanning gap. This design achieves local closed-loop feedback control, with fast dynamic response and strong real-time error compensation. Compared with traditional external control systems, this scheme integrates signal processing and control execution inside the probe, significantly shortening the control link, improving tracking accuracy and anti-interference capability, and is especially suitable for high-speed scanning and measurement of small features.

[0047] In a preferred embodiment, three sets of laser interferometers 4 move synchronously with the quantum tunneling probe 6. Three beams are incident on three orthogonal reflective surfaces 5, forming three mutually perpendicular static spatial reflection references. These references are used to measure the three-dimensional translational motion and three-dimensional rotational attitude of the quantum tunneling probe 6. The three beams converge at the measurement point of the quantum tunneling probe 6, eliminating Abbe error. The three-dimensional translation includes translation in the X, Y, and Z directions; the three-dimensional rotation includes rotation around the X, Y, and Z axes. The laser interferometers 4 measure the displacement and angular changes of the probe relative to the reference surfaces. Using the three sets of data, the translations in the X, Y, and Z directions and the rotations around the X, Y, and Z axes are calculated, resulting in the complete six-degree-of-freedom pose. Specifically, the laser interferometer 4 emits a beam of light towards the stationary tri-orthogonal reflector slope 5. The tri-orthogonal reflector slope 5 reflects the beam back into the laser interferometer 4 along its original path. Inside the laser interferometer 4, the emitted reference light and the reflected measurement light are superimposed to generate interference fringes. The signal processing module monitors the change in optical path difference corresponding to the interference fringes in real time and calculates the change in optical path of each of the three sets of beams to solve the displacement and rotation angle of the quantum tunneling probe 6. The design of the three sets of beams makes the geometric extensions of their measurement optical paths converge at the measurement point of the quantum tunneling probe 6 (the mechanical layout makes the extensions of the three beams intersect at the measurement point; the beams themselves do not contact the measurement point, only the geometric extensions of the optical paths intersect at the measurement point), so that the measurement reference point coincides with the actual workpiece measurement point, thereby eliminating the Abbe error introduced by the change in probe posture. This design eliminates the need for external auxiliary sensors, enabling simultaneous six-degree-of-freedom pose measurement and real-time calculation within the probe. Three optical paths converge at the measurement point, fundamentally eliminating Abbe arm errors and significantly improving the attitude-related accuracy in deep hole measurements with large aspect ratios. Three sets of laser interferometers 4 and the quantum tunneling probe 6 share a unified clock trigger, ensuring that each tunneling current data point has a unique corresponding pose information, achieving precise matching between measurement data and spatial attitude.

[0048] The root cause of Abbe error is that the reference point of the measurement optical path and the actual measured point of the workpiece do not coincide. That is, when the probe deflects or moves, additional measurement deviation will occur. In this solution, the optical path extension line converges to the measurement point, which is equivalent to directly coinciding the optical measurement reference with the measured point. Even if the probe rotates or deviates, no additional offset error will be generated, thus eliminating Abbe error from the root cause of the optical path structure.

[0049] The high-precision active scanning device for measuring deep holes with large aspect ratios of the present invention determines the motion displacement by using the distance information between the probe and the workpiece to maintain a quasi-contact state between the scanning device and the workpiece, thus completing the active scanning. The laser interferometer is fixed to the probe and works in conjunction with the three orthogonal reflective umbrellas distributed at the lower end of the housing to form a measurement loop, realizing the full calculation of the six degrees of freedom motion information of the probe. At the same time, the optical paths of the three laser interferometers converge at the probe, thereby eliminating Abbe error and improving measurement accuracy, achieving effective and reliable active scanning and integrated six-degree-of-freedom pose measurement functions.

[0050] The high-precision active scanning device for measuring deep holes with large aspect ratios of the present invention operates on the following principle: A quantum tunneling probe and a nanopiezoelectric driven motion stage cooperate to form an active scanning motion system that controls the movement of the probe. The quantum tunneling probe can measure the distance information between the probe and the support of the workpiece under test, and feed this information back to the nanopiezoelectric actuator. The actuator can then use this information to determine the magnitude of the input displacement and complete the automatic motion control of the probe. A laser interferometer is fixed to the probe and, as the probe moves, works in conjunction with three orthogonal reflective umbrellas distributed at the lower end of the housing to achieve precise measurement of the six degrees of freedom of the probe. At the same time, the Abbe error is eliminated through structural design, completing the six-degree-of-freedom pose measurement function. The specific measurement process is as follows:

[0051] After the high-precision active scanning device enters the deep hole measurement area, the non-contact quantum tunneling probe 6 first senses the distance to the surface of the workpiece. A nanoscale tunneling gap is formed between the microsphere 6-1 in the quantum tunneling probe 6 and the surface being measured. When the distance between the microsphere 6-1 and the surface being measured changes, the tunneling current changes exponentially with the gap distance. Therefore, the current change can be converted into real-time distance information between the microsphere 6-1 and the surface being measured.

[0052] During the measurement process, the signal processing module acquires the feedback current of the quantum tunneling probe 6 in real time:

[0053]

[0054] in, For tunneling current, The instantaneous distance between the probe and the surface being measured is denoted by , and k is the tunneling attenuation coefficient. After calibration, the signal processing module converts the current signal into a distance error signal.

[0055]

[0056] in, The preset scanning gap is used. This error signal is input in real time to the X / Y / Z-axis nanopiezoelectric drive controller. Through a closed-loop control algorithm, the motion stage is calculated to compensate for the displacement, driving the Z-axis nanopiezoelectric drive unit 1 and the XY-axis nanopiezoelectric drive unit 2 to generate micro-displacement adjustments, so that the micro-gauge ball 6-1 always remains near the set scanning distance. Therefore, the quantum tunneling probe 6 is not simply a distance sensor, but also a feedback element in the active scanning system, enabling the micro-gauge ball 6-1 to adaptively follow the contour of the hole wall.

[0057] To obtain the spatial coordinates of the measured point inside the deep hole, the quantum tunneling probe 6 alone cannot determine the positional change of the microsphere 6-1. Therefore, a tri-orthogonal umbrella 3 is fixedly connected to the quantum tunneling probe 6, with laser interferometers 4 distributed on the umbrellas, forming a follow-up pose measurement unit. The laser interferometer 4 moves synchronously with the microsphere 6-1, and its output beam is incident on the tri-orthogonal reflective surface slope 5 fixedly installed at the lower end of the housing 7, providing three spatial reflection references in mutually perpendicular directions. This allows the laser interferometer 4 to simultaneously measure the translation of the microsphere 6-1 in the X, Y, and Z directions, as well as its rotation around the X, Y, and Z axes. The signal processing module acquires the spatial pose signal, which can be expressed as:

[0058]

[0059] in, , , This indicates the center position of the micrometer ball 6-1. , , This indicates the attitude change of the micro-gauge 6-1. During the active scanning process, the two measurement systems operate synchronously using a unified clock triggering method. The signal processing module simultaneously acquires the quantum tunneling probe signal and the laser interference pose signal, meaning that each tunneling current data point corresponds to a specific spatial position and attitude. The final reconstructed three-dimensional contour of the deep hole is distortion-free, and the measurement accuracy of micromorphology, hole roundness, and deep hole axial dimensions is significantly better than that of traditional passive probes and split-type active scanning equipment.

[0060] This invention relates to a high-precision active scanning device for measuring deep holes with large aspect ratios. The probe has a built-in local closed-loop control system, which provides fast dynamic response and enables crosstalk-free nanometer-level micro-motion on all three axes. It relies on quantum tunneling sensing to complete non-contact constant gap adaptive scanning without damaging thin-walled workpieces. The probe integrates a laser interferometry six-degree-of-freedom pose detection module, which can simultaneously acquire the translation and deflection attitude of the probe to compensate for angular coupling errors. The optical path converges at the measurement point to eliminate Abbe errors at the structural level, significantly improving measurement accuracy. The entire active scanning and pose detection unit is integrated into a compact structure, which can extend into narrow deep holes with large aspect ratios for measurement. The modular design facilitates calibration and probe replacement. With the shell and signal shielding structure, it operates stably and reliably in industrial scenarios. Furthermore, the gap sensing and pose signals are acquired synchronously, and each sampling point can complete the pose error compensation, resulting in a precise and distortion-free three-dimensional contour of the deep hole.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An active scanning device for measuring deep holes with large aspect ratios, characterized in that, include: The displacement scanning module includes a quantum tunneling probe, a Z-axis nanopiezoelectric driving unit for adjusting the Z-direction driving displacement of the quantum tunneling probe, and an XY-axis nanopiezoelectric driving unit for adjusting the X-direction driving displacement and Y-direction driving displacement of the quantum tunneling probe, wherein the quantum tunneling probe sends a displacement signal. The pose measurement module includes three orthogonal umbrellas fixed to the quantum tunneling probe and moving synchronously with the quantum tunneling probe, three sets of laser interferometers uniformly distributed on the three orthogonal umbrellas, and three orthogonal reflection surface slopes located below the three orthogonal umbrellas as a stationary reflection reference, used to measure the pose change of the quantum tunneling probe, and the laser interferometers send pose signals. The signal processing module acquires the displacement signal and feeds it back to the Z-axis nanopiezoelectric drive unit and the XY-axis nanopiezoelectric drive unit for displacement adjustment in the X / Y / Z directions. Simultaneously, it acquires the pose signal to measure and calculate the three-dimensional translational motion and three-dimensional rotational attitude of the quantum tunneling probe. The XY-direction nanopiezoelectric drive unit includes a coaxially integrated X-direction nanopiezoelectric drive unit for outputting X-direction drive displacement and a Y-direction nanopiezoelectric drive unit for outputting Y-direction drive displacement. The Z-axis nanopiezoelectric drive unit is supported by the first output motion stage and outputs Z-direction drive displacement to the XY-axis nanopiezoelectric drive unit; The XY-direction nanopiezoelectric drive unit transmits the superimposed X-direction drive displacement and Y-direction drive displacement to the quantum tunneling probe through the second output motion stage; The quantum tunneling probe is fixed at the bottom of the second output motion stage.

2. The active scanning device according to claim 1, characterized in that, Also includes: The housing and the bottom plate have a detection hole for the quantum tunneling probe to extend out of the housing through the detection hole for active scanning of complex curved surfaces; The Z-axis nano-piezoelectric drive unit is fixed inside the top plate of the housing, and the three orthogonal reflective surface slopes are fixedly installed inside the bottom plate, with the central hole of the three orthogonal reflective surface slopes corresponding to and covering the detection hole.

3. The active scanning device according to claim 1, characterized in that, The Z-axis nanopiezoelectric drive unit includes a first flexible hinge, a first piezoelectric actuator disposed inside the first flexible hinge, and a first output motion stage connected to the first flexible hinge; wherein... The XY-axis nanopiezoelectric drive unit is fixedly connected to the bottom of the first output motion stage; The first piezoelectric actuator provides a driving displacement in the Z direction, and the first flexible hinge adjusts the displacement by outputting the driving displacement in the Z direction through the first output motion stage.

4. The active scanning device according to claim 1, characterized in that, The X-axis nanopiezoelectric drive unit includes an X-base mounted on one side of the bottom of the Z-axis nanopiezoelectric drive unit, an X sensor coaxially mounted with the X-base, an X connector fixedly connected to the X sensor on one side and moving parallel to the X-axis, and an X-axis nanopiezoelectric drive hinge mechanism fixed on the other side of the X connector.

5. The active scanning device according to claim 4, characterized in that, The X-direction nanopiezoelectric driven hinge mechanism includes a pair of symmetrically arranged X-flexible hinges and X-direction nanopiezoelectric actuators arranged opposite each other and assembled inside the X-flexible hinges, wherein... The Y-direction driving displacement generated by the X-direction nanopiezoelectric actuator is converted into the X-direction through the X flexible hinge, and the X-direction driving displacement is output through the second output motion stage.

6. The active scanning device according to claim 1, characterized in that, The Y-axis nanopiezoelectric drive unit includes a Y-base mounted on the other side of the bottom of the Z-axis nanopiezoelectric drive unit, a Y sensor coaxially mounted with the Y-base, a Y connector fixedly connected to the Y sensor on one side and moving parallel to the Y-axis, and a Y-axis nanopiezoelectric drive hinge mechanism fixed on the other side of the Y connector.

7. The active scanning device according to claim 6, characterized in that, The Y-direction nanopiezoelectric driven hinge mechanism includes a pair of symmetrically arranged Y-flexible hinges and a Y-direction nanopiezoelectric actuator arranged opposite to each other and assembled inside the Y-flexible hinges, wherein... The X-direction driving displacement generated by the Y-direction nanopiezoelectric actuator is converted to the Y-direction through the Y flexible hinge, and the Y-direction driving displacement is output through the second output motion stage.

8. The active scanning device according to claim 1, characterized in that, The quantum tunneling probe includes a microsphere, a signal transmission mechanism connected to the microsphere, a shielding mechanism that wraps around the signal transmission mechanism, a mounting mechanism located at the end of the shielding mechanism, a signal connector located at the mounting mechanism and connected to the signal transmission mechanism, and a transmission cable that connects to the signal connector and transmits signals.

9. The active scanning device according to claim 1, characterized in that, The signal processing module acquires the electrical signal of the quantum tunneling probe, converts the electrical signal into a distance error signal, and transmits the distance error signal to the Z-axis nanopiezoelectric drive unit and the XY-axis nanopiezoelectric drive unit for error closed-loop control, and performs displacement compensation adjustment in the X / Y / Z directions.

10. The active scanning device according to claim 1, characterized in that, The three sets of laser interferometers move synchronously with the quantum tunneling probe. Three beams are incident on the three orthogonal reflective surfaces, forming three mutually perpendicular static spatial reflection references. These references are used to measure the three-dimensional translational motion and three-dimensional rotational attitude of the quantum tunneling probe. Three beams converge at the measurement point of the quantum tunneling probe, eliminating Abbe measurement error; The three-dimensional translation refers to translation in the X direction, translation in the Y direction, and translation in the Z direction; The three-dimensional rotation refers to rotation around the X-axis, rotation around the Y-axis, and rotation around the Z-axis.

Images