Variable stiffness scanning probe with piezoelectric actuation mechanism bending deformation

Abstract

The application discloses a piezoelectric driving mechanism bending deformation variable stiffness scanning probe, which comprises a base, a deformation mechanism and a probe needle, the deformation mechanism comprises two deformation units which are fixed in a stack, the deformation unit comprises a circular ring and at least three V-shaped cantilever beams, the at least three V-shaped cantilever beams are arranged in the circular ring, one end of the at least three V-shaped cantilever beams is connected with the circular ring, and the other end is connected with each other and the connection position is located at the center of the circular ring; piezoelectric driving units and strain sensing units are arranged between the V-shaped cantilever beams of the two deformation units, and all the piezoelectric driving units are connected in parallel; the circular rings of the two deformation units are fixedly connected with the base, and the probe needle is connected with the other end of the V-shaped cantilever beams. The application can realize the large-range variable stiffness of the scanning probe to adapt to different modulus surfaces while the static and dynamic performances of the scanning probe are considered.

Description

A variable stiffness scanning probe for bending deformation driven by a piezoelectric mechanism Technical Field

[0001] This invention belongs to the field of precision dynamic measurement technology for high-end equipment components, specifically relating to a variable stiffness scanning probe for bending deformation of a piezoelectric driven mechanism. Background Technology

[0002] Precision equipment typically undergoes design, processing, inspection, assembly, and testing before being put into practical application. Precision probe inspection technology, as a key means of evaluating the quality and basic performance of precision components, plays a crucial role in the precision and quality inspection of high-end precision machine tools, large aircraft, satellites, and micro / nano components. With the diversification of inspection objects and scenarios, the uniformity of contact stiffness in precision probes is becoming an undeniable problem affecting inspection accuracy and restricting their widespread application. Different objects being measured typically have significantly different surface properties; a single probe stiffness can potentially damage the surface, degrading inspection quality. Due to the correlation between contact stiffness and probe dynamic characteristics, controllable stiffness variations can not only avoid surface damage but also adaptively balance the static and dynamic inspection characteristics of the probe according to specific inspection scenarios.

[0003] Patent CN110095050A discloses a triangular beam flexible constraint variable stiffness micro / nano probe. This patent proposes variable stiffness operation through the principle of column instability. However, this method has a limited range of variable stiffness, and the triangular effect of probe deformation and response error, i.e., the anisotropy of the error, becomes more prominent. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a variable stiffness scanning probe with piezoelectric drive mechanism for bending deformation, which, while taking into account the static and dynamic performance of the scanning probe, enables the scanning probe to adapt to a wide range of variable stiffness for surfaces with different moduli.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0006] A variable stiffness scanning probe for bending deformation driven by a piezoelectric mechanism includes a base, a deformation mechanism, and a probe. The deformation mechanism includes two deformation units stacked and fixed vertically. Each deformation unit includes a ring and at least three V-shaped cantilever beams. The at least three V-shaped cantilever beams are rotatably arrayed within the ring. One end of each V-shaped cantilever beam is connected to the ring, and the other ends are interconnected at the center of the ring. A piezoelectric driving unit and a strain sensing unit are disposed between the V-shaped cantilever beams of the two deformation units, and all piezoelectric driving units are connected in parallel. The rings of the two deformation units are fixedly connected to the base, and the probe is connected to the interconnection point at the other end of the V-shaped cantilever beams.

[0007] Furthermore, the piezoelectric drive unit is embedded on the upper surface of one beam of each of the lower V-shaped cantilever beams, and the strain sensing unit is embedded on the upper surface of the other beam of each of the lower V-shaped cantilever beams.

[0008] Furthermore, a first groove is formed on the upper surface of one beam of each V-shaped cantilever beam below, and the piezoelectric drive unit is embedded in the first groove; a second groove is formed on the upper surface of the other beam of each V-shaped cantilever beam below, and the strain sensing unit is embedded in the second groove.

[0009] Furthermore, the lower square variable unit is made of polymer material, while the upper square variable unit is made of alloy.

[0010] Furthermore, the two deformation units are bonded together using adhesive.

[0011] Furthermore, the included angle between the two beams of the V-shaped cantilever beam is 45° to 135°.

[0012] Furthermore, the base includes a housing and a deformation mechanism support frame connected within the housing, with the annular components of the two deformation units fixedly connected to the deformation mechanism support frame.

[0013] Furthermore, multiple first connecting holes are correspondingly provided on the annulus of the two deformation units, and a second connecting hole corresponding to the first connecting hole is provided on the deformation mechanism support frame. The two annulus of the deformation units are fixedly connected to the deformation mechanism support frame by passing a connecting rod through the first connecting hole and the second connecting hole.

[0014] Furthermore, a third connecting hole is provided at the connection point of the other end of the V-shaped cantilever beam, and one end of the probe is inserted and fixed in the third connecting hole.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects:

[0016] This invention provides a piezoelectric-driven variable stiffness scanning probe for bending deformation. The deformation mechanism includes two stacked and fixed deformation units. Each deformation unit comprises a ring and at least three V-shaped cantilever beams. The at least three V-shaped cantilever beams are rotatably arrayed within the ring, with one end connected to the ring and the other ends interconnected at the center of the ring. A piezoelectric driving unit and a strain sensing unit are disposed between the V-shaped cantilever beams of the two deformation units, and all piezoelectric driving units are connected in parallel. The piezoelectric driving unit, fixed to the V-shaped cantilever beams, utilizes the variable stiffness form of bending deformation. After applying voltage, it causes a large strain in the bending intersection area of ​​the V-shaped cantilever beams, resulting in significant upward or downward bending deformation of the V-shaped cantilever beams. This alters the overall stiffness of the mechanism, achieving a wider variable stiffness range in the V-shaped region compared to the traditional pressure bar instability principle, enabling the scanning probe to adapt to a wide range of variable stiffness on surfaces with different moduli. The piezoelectric drive unit and strain sensing unit are embedded between two stacked and fixed deformation units in a V-shaped cantilever beam, simplifying the overall variable stiffness scanning probe and reducing structural redundancy. All piezoelectric drive units are connected in parallel, employing a parallel synchronous drive system to achieve coordinated deformation drive of the deformation mechanism by at least three sets of piezoelectric drive units, ensuring no eccentricity of the probe stylus during the variable stiffness process.

[0017] Furthermore, the V-beam housing the piezoelectric drive unit and the strain sensing unit is made of a high-rigidity, low-density polymer material, while the other matching V-beam is made of an alloy material. The combination of polymer and alloy materials, compared to the traditional method that cannot effectively guarantee good dynamic characteristics of the probe while varying stiffness, enables the present invention to effectively ensure that the probe deformation mechanism has a high stiffness reference, while the low density of the polymer material ensures that the probe has good dynamic characteristics.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 is a schematic diagram of the overall structure of a variable stiffness scanning probe for bending deformation of a piezoelectric drive mechanism according to the present invention.

[0021] Figure 2 is a schematic diagram of the exploded structure of the deformation mechanism in the variable stiffness scanning probe of the piezoelectric drive mechanism bending deformation according to the present invention.

[0022] Figure 3 is a schematic diagram of the upper square variable unit structure in the deformation mechanism of the present invention;

[0023] Figure 4 is a schematic diagram of the lower square variable unit structure in the deformation mechanism of the present invention;

[0024] Figure 5 is a schematic diagram of the composition structure of the base in the variable stiffness scanning probe of the piezoelectric drive mechanism for bending deformation according to the present invention.

[0025] In the figure: 1-base; 10-shell; 11-deformation mechanism support frame; 110-mounting block; 2-deformation mechanism; 20-deformation unit; 200-ring; 201-V-shaped cantilever beam; 202-first groove; 203-second groove; 3-probe; 4-piezoelectric drive unit; 5-strain sensing unit; 6-first connecting hole; 7-second connecting hole; 8-third connecting hole; 9-assembly hole. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions 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, 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.

[0027] As a specific embodiment of the present invention, in conjunction with Figures 1 to 5, this embodiment provides a variable stiffness scanning probe with piezoelectric drive mechanism bending deformation, including a base 1, a deformation mechanism 2 and a probe 3. The deformation mechanism 2 includes two deformation units 20 stacked and fixed on top of each other. That is, the two deformation units 20 are stacked and fixed on top of each other to form the deformation mechanism 2, which constitutes the two-dimensional variable stiffness mechanism of the probe.

[0028] As shown in Figures 2, 3, and 4, the deformation unit 20 includes a circular ring 200 and three V-shaped cantilever beams 201. The three V-shaped cantilever beams 201 are arranged in a rotatable array within the circular ring 200. One end of each V-shaped cantilever beam 201 is connected to the circular ring 200, and the other ends are connected to each other at the center of the circular ring 200. For example, the circular ring 200 and the three V-shaped cantilever beams 201 are integrally formed.

[0029] As shown in Figure 2, a piezoelectric drive unit 4 and a strain sensing unit 5 are arranged between the V-shaped cantilever beams 201 of the two deformation units 20, with all piezoelectric drive units 4 connected in parallel. The piezoelectric drive unit 4 is a component that generates strain when a voltage is applied using the piezoelectric effect. The piezoelectric drive unit 4 is attached to one straight arm of each set of V-shaped cantilever beams 201. After applying voltage, the piezoelectric drive unit 4 causes a large strain in the bending intersection area of ​​the V-shaped cantilever beams 201, thereby changing the overall stiffness of the deformation mechanism 2. The strain sensing unit 5 is a high-precision strain gauge with micro-nano-level deformation sensing capability. The strain sensing unit 5 is attached to the other straight arm of each set of V-shaped cantilever beams 201 to sense the magnitude of the deformation of the deformation mechanism 2.

[0030] As shown in Figure 1, the annulus 200 of the two deformation units 20 is fixedly connected to the base 1, and the probe 3 is connected to the other end of the V-shaped cantilever beam 201 at the connection point. For example, the probe 3 includes a long rod and a spherical probe end connected to the end of the long rod. The long rod has high rigidity, and the spherical probe end has high wear resistance.

[0031] Based on the above embodiments, as a more preferred embodiment, as shown in FIG2, the piezoelectric drive unit 4 is embedded on the upper surface of one beam of each of the lower V-shaped cantilever beams 201, and the strain sensing unit 5 is embedded on the upper surface of the other beam of each of the lower V-shaped cantilever beams 201. For example, the piezoelectric drive unit 4 is embedded on the upper surface of one beam directly connected to the ring 200, and the strain sensing unit 5 is embedded on the upper surface of the other beam.

[0032] Specifically, the embedded piezoelectric drive unit 4 and strain sensing unit 5 enable the miniaturization of the probe, making the overall structure lighter and improving the sensitivity of probe stiffness and strain detection, allowing the probe to more sensitively sense structural deformation.

[0033] Based on the above embodiments, as a more preferred embodiment, as shown in FIG4, a first groove 202 is formed on the upper surface of one beam of each V-shaped cantilever beam 201 below. The piezoelectric drive unit 4 is embedded in the first groove 202, and after the piezoelectric drive unit 4 is embedded in the first groove 202, the upper surface of the piezoelectric drive unit 4 is flush with the upper surface of one beam of the V-shaped cantilever beam 201. A second groove 203 is formed on the upper surface of the other beam of each V-shaped cantilever beam 201 below. The strain sensing unit 5 is embedded in the second groove 203, and after the strain sensing unit 5 is embedded in the second groove 203, the upper surface of the strain sensing unit 5 is flush with the upper surface of the other beam of the V-shaped cantilever beam 201.

[0034] Based on the above embodiments, as a more preferred embodiment, the lower square variable unit 20 is made of a polymer material, for example, PVC, PE, etc., which have a good elastic modulus / strength ratio. The upper square variable unit 20 is made of an alloy, for example, beryllium bronze, 7075 aluminum alloy, etc.

[0035] Specifically, the lower square variable element 20 is made of polymer material, while the upper square variable element 20 is made of alloy. By combining the alloy and polymer materials, the advantages of the polymer material—lightweight and large linear deformation range—are utilized, enabling the probe to balance a large variable stiffness range with good dynamic characteristics. The lower square variable element 20 is typically selected from materials with a good elastic modulus / strength ratio. Its good stiffness characteristics and lightweight advantages can compensate for the insufficient overall stiffness of the probe caused by the large deformation of the lower square variable element 2. The upper square variable element 20 ensures the basic stiffness of the deformation mechanism 2 and is mainly used to generate a large deformation, thereby producing a large variable stiffness range.

[0036] Preferably, the two deformation units 20 are bonded together with an adhesive; for example, epoxy resin is used to bond the two deformation units 20 together.

[0037] Based on the above embodiments, as a more preferred embodiment, the included angle between the two beams of the V-shaped cantilever beam 201 is 45° to 135°. Angles within this range allow the V-shaped beam to generate a wider range of elastic deformation under the action of the piezoelectric drive unit, thereby ensuring a significant range of variable stiffness.

[0038] Based on the above embodiments, as a more preferred embodiment, as shown in FIG5, the base 1 includes a housing 10 and a deformation mechanism support frame 11 connected within the housing 10. Referring to FIG1, the annular rings 200 of the two deformation units 20 are fixedly connected to the deformation mechanism support frame 11. The shape of the deformation mechanism support frame 11 is not specifically limited, as long as it can provide the necessary fixing points or surfaces. For example, three mounting holes 9 are provided axially on the outer wall of the housing 10. The deformation mechanism support frame 11 is arranged in a triangular shape, with the three ends respectively assembled in the three mounting holes 9. A mounting block 110 is provided on the upper part of the deformation mechanism support frame 11 near the mounting end. The upper end surfaces of the three mounting blocks 110 are located on the same horizontal plane, and a second connecting hole 7 corresponding to the first connecting hole 6 is provided on the upper end surface of each mounting block 110.

[0039] In this embodiment, as shown in Figures 2, 3, and 4, multiple first connecting holes 6 are correspondingly provided on the annulus 200 of the two deformation units 20. As shown in Figure 5, second connecting holes 7 corresponding to the first connecting holes 6 are provided on the deformation mechanism support frame 11. As shown in Figure 1, a connecting rod passes through the first connecting holes 6 and the second connecting holes 7 to fix the annulus 200 of the two deformation units 20 to the deformation mechanism support frame 11. For example, the connecting rod is a screw, and the first connecting holes 6 and the second connecting holes 7 are threaded holes. The fixed connection between the deformation mechanism 2 and the deformation mechanism support frame 11 is achieved through the screw and thread engagement.

[0040] In this embodiment, as shown in Figures 1 and 2, a third connecting hole 8 is provided at the connection point of the other end of the V-shaped cantilever beam 201. The third connecting hole 8 is used to assemble the probe 3, and one end of the probe 3 is inserted and fixed in the third connecting hole 8.

[0041] The present invention provides a variable stiffness scanning probe for bending deformation driven by a piezoelectric drive mechanism, which achieves the following functionality:

[0042] (1) Parallel synchronous drive: Apply the same voltage to the piezoelectric drive unit on the V-shaped cantilever beam (3 groups or more) of the deformation mechanism to make the V-shaped cantilever beam bend upward or downward, thereby changing the overall stiffness of the probe.

[0043] (2) Simultaneous strain sensing: The strain sensing unit is used to obtain the deformation of the V-shaped cantilever beam of the deformation mechanism in real time, and the deformation is converted into physical quantities such as voltage and current through signal processing steps such as analog-to-digital conversion.

[0044] (3) Variable stiffness curve calibration: Within the deformable range of the deformation, a series of discrete voltage-driven calibration experiments were designed to calibrate the three-level mapping relationship between driving voltage, deformation, and overall probe stiffness under different voltage driving conditions. The calibration of the overall probe stiffness adopted a general force-displacement calibration method, which will not be elaborated here. The final constructed driving voltage-probe stiffness mapping curve can be used to guide the adaptive adjustment of probe contact stiffness in practical testing applications.

[0045] (4) Adaptive variable stiffness: Considering the soft and hard characteristics of the surface of the measured parts in actual measurement, the contact stiffness of the probe is changed by adjusting the driving voltage in a targeted manner according to the established voltage-stiffness mapping curve, so as to avoid damage to the surface of the measured parts.

[0046] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A variable stiffness scanning probe for bending deformation driven by a piezoelectric mechanism, characterized in that, The device includes a base (1), a deformation mechanism (2), and a probe (3). The deformation mechanism (2) includes two deformation units (20) stacked and fixed on top of each other. Each deformation unit (20) includes a ring (200) and at least three V-shaped cantilever beams (201). The at least three V-shaped cantilever beams (201) are arranged in a rotating array within the ring (200). One end of each of the at least three V-shaped cantilever beams (201) is connected to the ring (200), and the other ends are connected to each other at the center of the ring (200). A piezoelectric drive unit (4) and a strain sensing unit (5) are arranged between the V-shaped cantilever beams (201) of the two deformation units (20). All piezoelectric drive units (4) are connected in parallel; the annulus (200) of the two deformation units (20) is fixedly connected to the base (1), and the probe (3) is connected to the other end of the V-shaped cantilever beam (201); the piezoelectric drive unit (4) is embedded on the upper surface of one beam of each V-shaped cantilever beam (201) below, and the strain sensing unit (5) is embedded on the upper surface of the other beam of each V-shaped cantilever beam (201) below; or, the piezoelectric drive unit (4) is attached to one straight long arm of each group of V-shaped cantilever beams (201), and the strain sensing unit (5) is attached to the other straight long arm of each group of V-shaped cantilever beams (201).

2. The variable stiffness scanning probe for bending deformation of a piezoelectric driven mechanism according to claim 1, characterized in that, A first groove (202) is provided on the upper surface of one beam of each V-shaped cantilever beam (201) below, and the piezoelectric drive unit (4) is embedded in the first groove (202); a second groove (203) is provided on the upper surface of the other beam of each V-shaped cantilever beam (201) below, and the strain sensing unit (5) is embedded in the second groove (203).

3. The variable stiffness scanning probe for bending deformation of a piezoelectric driven mechanism according to claim 1, characterized in that, The lower square variable unit (20) is made of polymer material, and the upper square variable unit (20) is made of alloy.

4. The variable stiffness scanning probe for bending deformation of a piezoelectric driven mechanism according to claim 1, characterized in that, The two deformation units (20) are bonded together with adhesive.

5. The variable stiffness scanning probe for bending deformation of a piezoelectric driven mechanism according to claim 1, characterized in that, The included angle between the two beams of the V-shaped cantilever beam (201) is 45°~135°.

6. The variable stiffness scanning probe for bending deformation of a piezoelectric driven mechanism according to claim 1, characterized in that, The base (1) includes a housing (10) and a deformation mechanism support frame (11) connected inside the housing (10), with the rings (200) of the two deformation units (20) fixedly connected to the deformation mechanism support frame (11).

7. The variable stiffness scanning probe for bending deformation of a piezoelectric driven mechanism according to claim 6, characterized in that, Multiple first connecting holes (6) are provided on the annulus (200) of the two deformation units (20), and a second connecting hole (7) corresponding to the first connecting hole (6) is provided on the deformation mechanism support frame (11). The annulus (200) of the two deformation units (20) is fixedly connected to the deformation mechanism support frame (11) by passing a connecting rod through the first connecting hole (6) and the second connecting hole (7).

8. The variable stiffness scanning probe for bending deformation of a piezoelectric driven mechanism according to claim 1, characterized in that, A third connecting hole (8) is provided at the connection point of the other end of the V-shaped cantilever beam (201), and one end of the probe (3) is inserted and fixed in the third connecting hole (8).

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