Inertia-based measuring device

Abstract

The invention discloses a measuring device based on inertia, and relates to the field of inertia measurement. A near-zero rigidity mechanism is arranged in the shell, the middle polar plate is connected with the inner side wall of the shell through the near-zero rigidity mechanism, and the middle polar plate is supported by the near-zero rigidity mechanism, so that the middle polar plate is in a near-zero rigidity state and can be used as an inertial measurement reference point; the shell drives the upper polar plate and the lower polar plate to move synchronously, the position of the inertial measurement reference point is kept unchanged under the action of the near-zero stiffness mechanism, and the distance between the upper polar plate and the middle polar plate and the distance between the lower polar plate and the middle polar plate are changed, so that the capacitance between the upper polar plate and the middle polar plate and the capacitance between the lower polar plate and the middle polar plate are changed; and the vibration direction and the vibration amplitude of the shell are determined through the change of the capacitance, so that the effective control of low-frequency vibration is realized, and the manufacturing and measuring precision of nano-scale and sub-nano-scale precision is improved.

Description

Technical Field

[0001] This invention relates to the field of inertial measurement, and in particular to an inertial-based measurement device. Background Technology

[0002] As high-end manufacturing, such as integrated circuits and optical components, continues to advance towards nanometer and sub-nanometer precision, extreme demands are placed on the control of micro-vibrations in the machining and measurement environment. Even minute relative displacements between the worktable and the cutting tool can lead to process failures and precision losses, especially in the low-frequency range, where traditional vibration isolation methods struggle to effectively detect and filter such slow drifts.

[0003] To this end, an inertial reference point with near-zero stiffness can be constructed. This reference point is highly insensitive to low-frequency vibrations that are widespread on the ground and the platform itself (such as building swaying and equipment thermal disturbances). It can maintain near-absolute dynamic stillness over a wide frequency band. By detecting the relative motion between the inertial reference point and the worktable on which the tool or workpiece is mounted, the ultra-low frequency and nanometer-level undesired drift and vibration of the worktable can be accurately extracted, thereby achieving effective control of low-frequency vibrations. Summary of the Invention

[0004] The purpose of this invention is to provide an inertial-based measurement device to solve the problems existing in the prior art, achieve effective control of low-frequency vibration, and improve machining accuracy.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides an inertial-based measurement device, including a housing and a near-zero stiffness mechanism. An upper electrode plate and a lower electrode plate are respectively provided on the top and bottom surfaces inside the housing, and the upper and lower electrode plates are correspondingly arranged. An intermediate electrode plate is provided between the upper and lower electrode plates, and the intermediate electrode plate is connected to the housing through the near-zero stiffness mechanism.

[0006] In one embodiment, a permanent magnet is disposed in the intermediate electrode plate, and a coil is disposed on the top of the lower electrode plate.

[0007] In one embodiment, the near-zero stiffness mechanism includes a first support member providing positive stiffness and a second support member providing negative stiffness.

[0008] In one embodiment, at least two sets of near-zero stiffness mechanisms are provided, and the near-zero stiffness mechanisms are evenly distributed along the circumference of the intermediate electrode plate.

[0009] In one embodiment, the first support is a pre-compressed buckling beam, and the second support is a spring. The two ends of the pre-compressed buckling beam are connected to the inner side of the outer shell and the side of the intermediate electrode plate, respectively, and the two ends of the spring are connected to the top and bottom of the outer shell, respectively.

[0010] In one embodiment, the preloaded buckling beam and the spring are connected at the same location as the intermediate electrode plate.

[0011] In one embodiment, an extension platform is provided on the side of the intermediate electrode plate, and the pre-compression buckling beam and the spring are both connected to the intermediate electrode plate through the extension platform.

[0012] In one embodiment, a through hole is provided at the top of the outer shell, the through hole penetrating the top of the outer shell and the upper electrode plate, and a vertical rod penetrating the through hole is provided at the top of the middle electrode plate, with the end of the vertical rod away from the middle electrode plate serving as an inertial reference point.

[0013] The present invention achieves the following technical effects compared to the prior art: The shell has a near-zero stiffness mechanism inside, and the intermediate electrode plate is connected to the inner wall of the shell through the near-zero stiffness mechanism. The near-zero stiffness mechanism supports the intermediate electrode plate, keeping it in a near-zero stiffness state. The intermediate electrode plate does not vibrate synchronously with the shell, that is, the intermediate electrode plate remains in its initial position when the shell vibrates. The intermediate electrode plate can be used as an inertial measurement reference point. When the shell is subjected to external force and vibrates, the shell drives the upper and lower electrode plates to move synchronously. The position of the inertial measurement reference point remains fixed, and the distance between the upper and lower electrode plates and the intermediate electrode plate changes. This changes the capacitance between the upper electrode plate and the intermediate electrode plate, as well as between the lower electrode plate and the intermediate electrode plate. The vibration direction and amplitude of the shell are determined by the change in capacitance, realizing effective control of low-frequency vibration and improving the manufacturing and measurement accuracy at the nanometer and sub-nanometer levels. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the overall structure of the inertial-based measurement device in an embodiment of the present invention; Figure 2 This is a cross-sectional view of the inertial-based measurement device in an embodiment of the present invention; The components are: 1. Pre-compressed buckling beam; 2. Spring; 3. Upper electrode plate; 4. Inertial reference point; 5. Outer shell; 6. Lower electrode plate; 7. Coil; 8. Middle electrode plate; 9. Base. Detailed Implementation

[0016] 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.

[0017] The purpose of this invention is to provide an inertial-based measurement device to solve the problems existing in the prior art and achieve effective control of low-frequency vibrations.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Please refer to Figures 1 to 2 This embodiment provides an inertial-based measuring device. A near-zero stiffness mechanism is provided inside the outer casing 5. The intermediate electrode plate 8 is connected to the inner wall of the outer casing 5 through the near-zero stiffness mechanism, fixing the intermediate electrode plate 8 inside the outer casing 5 and placing it in a near-zero stiffness state. When the outer casing 5 vibrates along the directions of the upper electrode plate 3 and the lower electrode plate 6, the upper electrode plate 3 and the lower electrode plate 6 move synchronously with the outer casing 5, while the intermediate electrode plate 8 does not vibrate synchronously with the outer casing 5 due to inertia. That is, the near-zero stiffness mechanism keeps the position of the intermediate electrode plate 8 within the outer casing 5 unchanged. The intermediate electrode plate 8 can serve as a reference point for inertial measurement of the vibration amplitude and direction of the outer casing 5. As the outer casing 5 vibrates, the distances between the upper electrode plate 3 and the intermediate electrode plate 8, and between the lower electrode plate 6 and the intermediate electrode plate 8, change, thereby altering the capacitance between the upper electrode plate 3 and the intermediate electrode plate 8, and between the lower electrode plate 6 and the intermediate electrode plate 8. The vibration direction and amplitude of the outer casing 5 can be determined by the change in capacitance.

[0020] Preferably, to facilitate the installation of the near-zero stiffness mechanism inside the housing 5, a base 9 is provided at the bottom of the housing 5, and the base 9 is detachably connected to the bottom of the housing 5.

[0021] A permanent magnet is also provided in the intermediate pole plate 8, and a coil 7 is provided on the top of the lower pole plate 6. The coil 7 generates a magnetic field when energized. The interaction between the magnetic field generated by the coil 7 and the permanent magnet adjusts the relative position of the intermediate pole plate 8 in the outer shell 5, so as to compensate for the numerical error of positive stiffness and negative stiffness in the near-zero stiffness mechanism. While keeping the intermediate pole plate 8 in a near-zero stiffness state, the structure of the near-zero stiffness mechanism is simplified and the cost of use is reduced. After the near-zero stiffness state is destroyed by external force, the direction and magnitude of the current in the coil 7 can be changed, and the interaction between the magnetic field of the coil 7 and the permanent magnet can be used to adjust the intermediate pole plate 8 back to the near-zero stiffness state, thereby improving the reliability of the near-zero stiffness mechanism.

[0022] The near-zero stiffness mechanism includes a first support member that provides positive stiffness to the intermediate electrode plate 8 and a second support member that provides negative stiffness to the intermediate electrode plate 8. The positive stiffness applied to the intermediate electrode plate 8 by the first support member and the negative stiffness applied to the intermediate electrode plate 8 by the second support member keep the intermediate electrode plate 8 in a state of force balance, maintain the relatively fixed position of the intermediate electrode plate 8 in the outer shell 5, and, together with the coil 7 and the permanent magnet, ensure the stability of the near-zero stiffness mechanism in the working state.

[0023] At least two sets of near-zero stiffness mechanisms are provided, and the near-zero stiffness mechanisms are evenly distributed along the circumference of the intermediate electrode plate 8. In this embodiment, four sets of near-zero stiffness mechanisms are provided, and the four sets of near-zero stiffness mechanisms are spaced apart on the side of the intermediate electrode plate 8. In order to ensure the stability of the near-zero stiffness state of the intermediate electrode plate 8, the angle between the line connecting the two adjacent sets of near-zero stiffness mechanisms and the center of the intermediate electrode plate 8 is 90 degrees.

[0024] In this embodiment, the first support is a pre-compressed buckling beam 1, and the second support is a spring 2. The pre-compressed buckling beam 1 is bent as a whole, and its two ends are connected to the inner side of the outer shell 5 and the extension platform, respectively. The spring 2 passes through the extension platform, and its two ends are connected to the top and bottom of the outer shell 5, respectively. The spring 2 provides positive stiffness to the intermediate electrode plate 8, and the pre-compressed buckling beam 1 provides negative stiffness to the intermediate electrode plate 8. The two stiffnesses are equal in value but opposite in direction, so that the intermediate electrode plate 8 is in a near-zero stiffness state under the combined action of the pre-compressed buckling beam 1 and the spring 2. Furthermore, since the outer shell 5 needs to keep the intermediate electrode plate 8 in its initial position during vibration, the pre-compressed buckling beam 1 can be fixedly connected to the inner side of the outer shell 5 or rotatedly connected, while the connection between the pre-compressed buckling beam 1 and the extension platform can only be a rotational connection, thereby preventing the pre-compressed buckling beam 1 from driving the intermediate electrode plate 8 to move.

[0025] In this embodiment, the pre-compression buckling beam 1 is disposed between the side of the intermediate electrode plate 8 and the inner wall of the outer shell 5. The pre-compression buckling beam 1 provides negative stiffness to the intermediate electrode plate 8, while the two ends of the spring 2 are disposed between the top and bottom of the outer shell 5 to provide positive stiffness to the intermediate electrode plate 8. The intermediate electrode plate 8 is kept in a near-zero stiffness state by the joint action of the spring 2 and the pre-compression buckling beam 1. Therefore, the spring 2 and the pre-compression buckling beam 1 are connected to the intermediate electrode plate 8 at the same position, so that the intermediate electrode plate 8 and the connection point of the spring 2 and the pre-compression buckling beam 1 are in force balance.

[0026] Preferably, to facilitate the connection between the spring 2 and the pre-compressed buckling beam 1 and the intermediate electrode plate 8, an extension platform is provided on the side of the intermediate electrode plate 8. The spring 2 and the pre-compressed buckling beam 1 are connected to the intermediate electrode plate 8 through the extension platform. Furthermore, since the intermediate electrode plate 8 is in a near-zero stiffness state, and the extension platform is integrally formed with the intermediate electrode plate 8, the extended platform is also in a near-zero stiffness state. Therefore, the position of the extension platform in space is relatively static, and thus the extension platform can be regarded as an inertial measurement reference.

[0027] The top of the outer shell 5 is also provided with a through hole, which passes through the top of the outer shell 5 and the upper electrode plate 3. The top of the middle electrode plate 8 is provided with a vertical rod that passes through the through hole. The end of the vertical rod away from the middle electrode plate 8 is the inertial reference point 4. The inertial reference point 4 is located outside the outer shell 5. When the outer shell 5 is vibrated, the vibration of the outer shell 5 can be observed through the inertial reference point 4.

[0028] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0029] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0030] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An inertial-based measurement device, characterized in that, The device includes an outer shell (5) and a near-zero stiffness mechanism. The top and bottom surfaces inside the outer shell (5) are respectively provided with an upper electrode plate (3) and a lower electrode plate (6). The upper electrode plate (3) and the lower electrode plate (6) are respectively provided. An intermediate electrode plate (8) is provided between the upper electrode plate (3) and the lower electrode plate (6). The intermediate electrode plate (8) is connected to the outer shell (5) through the near-zero stiffness mechanism.

2. The inertial-based measurement device according to claim 1, characterized in that, A permanent magnet is provided in the intermediate pole plate (8), and a coil (7) is provided on the top of the lower pole plate (6).

3. The inertial-based measurement device according to claim 1, characterized in that, The near-zero stiffness mechanism includes a first support member that provides positive stiffness and a second support member that provides negative stiffness.

4. The inertial-based measurement device according to claim 3, characterized in that, At least two sets of the near-zero stiffness mechanism are provided, and the near-zero stiffness mechanism is evenly distributed along the circumference of the intermediate pole plate (8).

5. The inertial-based measurement device according to claim 4, characterized in that, The first support is a pre-compressed buckling beam (1), and the second support is a spring (2). The two ends of the pre-compressed buckling beam (1) are respectively connected to the inner side of the outer shell (5) and the side of the intermediate pole plate (8). The two ends of the spring (2) are respectively connected to the top and bottom of the outer shell (5).

6. The inertial-based measurement device according to claim 5, characterized in that, The pre-stressed buckling beam (1) and the spring (2) are connected at the same position to the intermediate pole plate (8).

7. The inertial-based measurement device according to claim 6, characterized in that, An extension platform is provided on the side of the intermediate electrode plate (8), and the pre-compression buckling beam (1) and the spring (2) are both connected to the intermediate electrode plate (8) through the extension platform.

8. The inertial-based measurement device according to claim 1, characterized in that, The top of the outer shell (5) is provided with a through hole, which penetrates the top of the outer shell (5) and the upper electrode plate (3). The top of the middle electrode plate (8) is provided with a vertical rod that penetrates the through hole, and the end of the vertical rod away from the middle electrode plate (8) is an inertial reference point (4).

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