Variable-direction capacitive displacement sensor based on corrugated structure

Abstract

The invention discloses a variable-direction capacitance displacement sensor based on a corrugated structure, which belongs to the field of displacement measurement and comprises a capacitor shell provided with a capacitor lower pole plate and a capacitor upper pole plate which are oppositely arranged. A movable electrode is arranged at the position, between the capacitor lower pole plate and the capacitor upper pole plate, of the capacitor shell through a corrugated mechanism, the capacitor shell is further provided with a self-adaptive mechanism capable of counteracting gravity interference of the movable electrode, and the corrugated mechanism is used for restraining unexpected angular displacement of the movable electrode. And the corrugated mechanism is matched with the self-adaptive mechanism to enable the sensor to be used in multiple directions, the corrugated mechanism comprises an annular frame fixed on the capacitor shell, and a corrugated sheet is arranged in the annular frame. According to the variable-direction capacitance displacement sensor based on the corrugated structure, inclination of the movable electrode can be restrained, the sensor adapts to multiple use directions, the problems of non-parallel errors and limited directions of a traditional sensor are solved, and the measurement precision, the linearity, the stability and the multifunctionality are improved.

Description

Technical Field

[0001] This invention relates to the field of displacement measurement technology, and in particular to a variable direction capacitive displacement sensor based on a corrugated structure. Background Technology

[0002] High-precision displacement measurement is a core technological requirement in precision manufacturing, micro-nano manipulation, and advanced instrumentation. As related technologies advance towards micron and even nanometer-level precision, unprecedentedly stringent requirements are placed on the measurement accuracy, linearity, and long-term stability of displacement sensors. Capacitive displacement sensors, with their advantages of non-contact operation, high sensitivity, and simple structure, have become an important means of achieving high-precision displacement measurement. Currently, high-precision capacitive displacement sensors generally employ a parallel-plate capacitor structure consisting of a moving electrode and a fixed electrode for displacement measurement. To maintain high accuracy and linearity, the core requirement is that the moving electrode remains perfectly parallel to the fixed electrode throughout its movement, avoiding angular displacement deviation (tilt). Existing technologies mainly attempt to address the tilting problem of the moving electrode through the following three schemes:

[0003] Precision mechanical leveling mechanism: This solution achieves initial static parallelism through adjusting screws, wedges, and other mechanisms during assembly. However, it can only compensate for static or quasi-static assembly errors and is completely incapable of adapting to dynamic, real-time angular displacement deviations caused by motion coupling, external force disturbances, or thermal deformation during operation. Furthermore, this solution suffers from cumbersome adjustment and long-term stability issues due to mechanical creep and loosening.

[0004] Flexible hinge guiding structure: This scheme utilizes precision-machined flexible hinges to constrain the undesired angular displacement of the moving electrode. However, to achieve high-precision angular displacement constraint (high anti-tilting stiffness), the design of the flexible hinge often leads to a significant increase in stiffness in the desired motion direction (axial direction), severely limiting the effective displacement range of the sensor. Furthermore, the precision machining of flexible hinges is difficult and costly, and they are prone to introducing parasitic vibrations and hysteresis nonlinearities under large loads or high frequencies.

[0005] Active / passive feedback tilt compensation: This scheme integrates additional tilt sensors and actuators (such as piezoelectric ceramics) to detect and dynamically compensate for tilt in real time. However, the system complexity, cost, and potential failure points increase dramatically. The additional sensing elements introduce new sources of measurement error, and the design, power consumption, stability, and potential electromagnetic interference of the compensation actuator and its control system all pose new challenges, significantly reducing the overall reliability and practicality of the system. Furthermore, this scheme places extremely high demands on the accuracy and response speed of the control algorithm.

[0006] The existing technologies described above suffer from a core problem: they cannot effectively, reliably, and cost-effectively suppress the dynamic angular displacement deviation of the moving electrodes during operation, leading to misalignment of the electrodes and consequently causing significant nonlinear capacitive response and a decrease in measurement accuracy. Therefore, this invention proposes a variable-direction capacitive displacement sensor based on a corrugated structure. Summary of the Invention

[0007] The purpose of this invention is to solve the problems of non-parallelism error between the moving electrode and the fixed electrode caused by the swinging of the moving electrode in existing capacitive displacement sensors, and the inability of capacitive displacement sensors to change their direction of use, and to propose a variable direction capacitive displacement sensor based on a corrugated structure.

[0008] To achieve the above objectives, the present invention employs the following technology: a variable direction capacitive displacement sensor based on a corrugated structure, comprising a capacitor housing, wherein a lower capacitor plate and an upper capacitor plate are disposed on the capacitor housing and arranged opposite to each other, and a movable electrode is disposed on the capacitor housing between the lower capacitor plate and the upper capacitor plate via a corrugated mechanism; the capacitor housing is also provided with an adaptive mechanism capable of counteracting the gravitational interference of the movable electrode.

[0009] The corrugated mechanism is used to constrain the undesired angular displacement of the active electrode, and its cooperation with the adaptive mechanism enables the sensor to be used in multiple directions.

[0010] As a further description of the above technical solution: the corrugated mechanism includes an annular frame fixed on the capacitor shell, and a corrugated sheet is disposed inside the annular frame.

[0011] As a further description of the above technical solution: the number of corrugated sheets is several, and they are arranged in a multi-layer nested manner around the axis of the movable electrode.

[0012] As a further description of the above technical solution: the corrugated sheet can be integrally formed by stamping or etching.

[0013] As a further description of the above technical solution: the adaptive mechanism includes a flexible angle connecting rod connected to the active electrode, and a counterweight is provided at the end of the flexible angle connecting rod away from the active electrode via a rotating connecting rod, wherein the counterweight is located outside the capacitor shell.

[0014] As a further description of the above technical solution: a magnet is provided on the capacitor shell, and the magnet can generate a magnetic attraction force on the rotating connecting rod.

[0015] As a further description of the above technical solution: when the sensor is placed horizontally, the magnetic attraction force of the magnet is less than the weight of the counterweight;

[0016] When the sensor is placed vertically, the magnetic attraction force of the magnet is greater than the combined force of the rotating connecting rod and the counterweight.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] By setting a corrugated mechanism, the corrugated mechanism has low stiffness in the desired motion direction (axial direction) of the moving electrode to allow large-stroke linear motion, and high stiffness in the undesired angular displacement direction (radial direction) to constrain tilting. This effectively suppresses the dynamic angular displacement deviation of the moving electrode, avoids its misalignment with the fixed electrode (upper and lower plates of the capacitor), eliminates nonlinear capacitance changes caused by non-parallel errors, and significantly improves the sensor's measurement accuracy, linearity, and long-term stability.

[0019] The adaptive mechanism enables the sensor to be used flexibly in multiple directions without the need for manual adjustment or recalibration, expanding its application scenarios in precision manufacturing, micro-nano manipulation and other fields, and improving its multifunctionality and deployment flexibility. Attached Figure Description

[0020] Figure 1 An exploded view is shown according to an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the overall structure provided according to an embodiment of the present invention is shown;

[0022] Figure 3 A front view provided according to an embodiment of the present invention is shown;

[0023] Figure 4 A cross-sectional view provided according to an embodiment of the present invention is shown.

[0024] Legend:

[0025] 1. Lower capacitor plate; 2. Corrugated mechanism; 3. Movable electrode; 4. Upper capacitor plate; 5. Capacitor casing; 6. Counterweight; 7. Rotating connecting rod; 8. Magnet; 9. Flexible angle connecting rod. Detailed Implementation

[0026] 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.

[0027] Reference Figures 1-4This embodiment provides a variable direction capacitive displacement sensor based on a corrugated structure, including a capacitor housing 5. A lower capacitor plate 1 and an upper capacitor plate 4 are arranged opposite to each other on the capacitor housing 5. A movable electrode 3 is arranged on the capacitor housing 5 between the lower capacitor plate 1 and the upper capacitor plate 4 through a corrugated mechanism 2. The corrugated mechanism 2 includes an annular frame fixed on the capacitor housing 5. Corrugated sheets are arranged inside the annular frame. The number of corrugated sheets is several and they are arranged in a multi-layer nested manner around the axis of the movable electrode 3. The corrugated mechanism 2 is used to constrain the undesired angular displacement of the movable electrode 3.

[0028] In this invention, the capacitor housing 5 serves as a fixed carrier, on which the lower electrode 1 and the upper electrode 4 are arranged opposite each other to form a fixed electrode pair for capacitance measurement. When the sensor is working, the movable electrode 3 needs to make linear movements along the direction parallel to the normal of the lower electrode 1 and the upper electrode 4 (the desired direction of movement) to achieve displacement measurement. At this time, the multi-layered nested corrugated sheets in the corrugated mechanism 2 have low stiffness characteristics in the axial direction (the desired direction of movement) and can elastically deform synchronously with the movable electrode 3, allowing the movable electrode 3 to make large-stroke linear movements. At the same time, the corrugated sheets have high stiffness characteristics in the radial direction perpendicular to the desired direction of movement, i.e., the direction of undesired angular displacement, which can constrain the tilt of the movable electrode 3 and prevent it from generating undesired angular displacement. The corrugated mechanism 2 eliminates the nonlinear capacitance change caused by non-parallel errors, thereby improving the measurement accuracy and linearity of the sensor.

[0029] It should be noted that corrugated sheets can be integrally formed by stamping or etching. When stamping, the corrugated sheet is integrally formed from a thin metal sheet (such as brass or phosphor bronze) using a stamping die. When etching, the corrugated sheet is based on a thin metal sheet (such as stainless steel or titanium alloy) and the corrugations are processed by chemical etching or laser etching. The difficulty and cost of stamping or etching are far lower than those of precision flexible hinges, greatly improving the manufacturability and economy of the design.

[0030] The capacitor housing 5 is also provided with an adaptive mechanism that can counteract the gravitational interference of the movable electrode 3. The adaptive mechanism includes a flexible angle connecting rod 9 connected to the movable electrode 3. The end of the flexible angle connecting rod 9 away from the movable electrode 3 is provided with a counterweight 6 via a rotating connecting rod 7. The counterweight 6 is located outside the capacitor housing 5. A magnet 8 is provided on the capacitor housing 5. The magnet 8 can generate a magnetic attraction force on the rotating connecting rod 7. When the sensor is placed horizontally, the magnetic attraction force of the magnet 8 is less than the weight of the counterweight 6.

[0031] When the sensor is placed vertically, the magnetic attraction force of magnet 8 is greater than the combined force of rotating link 7 and counterweight 6. The corrugated mechanism 2, in conjunction with the adaptive mechanism, enables the sensor to be used in multiple directions.

[0032] When the sensor is placed horizontally, the gravity of the movable electrode 3 will cause it to tend to shift downwards. At this time, the magnetic attraction force of the magnet 8 on the rotating connecting rod 7 is less than the weight of the counterweight 6. Under the action of gravity, the counterweight 6 pulls the rotating connecting rod 7 downwards. The rotating connecting rod 7 transmits the pulling force to the flexible angle connecting rod 9. After being subjected to force, the flexible angle connecting rod 9 undergoes a slight deformation, applying an upward lifting force to the movable electrode 3 to counteract the gravitational shift of the movable electrode 3 and maintain its parallelism with the lower electrode 1 and the upper electrode 4 of the capacitor. When the sensor is placed vertically, the direction of gravity of the movable electrode 3 is consistent with the desired direction of movement, and no additional counteracting is required. At this time, the magnetic attraction force of the magnet 8 on the rotating connecting rod 7 is less than the weight of the counterweight 6. The magnetic attraction force of the rotating link 7 is greater than the resultant force of the rotating link 7 and the counterweight 6, thus attracting and fixing the rotating link 7. This prevents the rotating link 7 and the counterweight 6 from interfering with the normal linear movement of the movable electrode 3 along the axial direction due to their own weight or vibration. This purely mechanical switching mechanism allows the sensor to automatically maintain the correct parallel position relationship between the movable electrode 3 and the lower electrode 1 and the upper electrode 4 of the capacitor when used in the horizontal or vertical direction without manual structural adjustment or recalibration. This significantly expands the application scenarios of the sensor (such as from machine tool horizontal guide rails to robot vertical joints) and improves its multifunctionality and deployment flexibility.

[0033] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A variable-direction capacitive displacement sensor based on a corrugated structure, characterized in that, The capacitor includes a capacitor housing (5), on which a lower capacitor plate (1) and an upper capacitor plate (4) are arranged opposite to each other. A movable electrode (3) is provided on the capacitor housing (5) between the lower capacitor plate (1) and the upper capacitor plate (4) via a corrugated mechanism (2). The capacitor housing (5) is also provided with an adaptive mechanism that can counteract the gravitational interference of the movable electrode (3). The corrugated mechanism (2) is used to constrain the undesired angular displacement of the active electrode (3), and its cooperation with the adaptive mechanism enables the sensor to be used in multiple directions.

2. The variable direction capacitive displacement sensor based on a corrugated structure according to claim 1, characterized in that, The corrugated mechanism (2) includes an annular frame fixed on the capacitor housing (5), and a corrugated sheet is provided inside the annular frame.

3. A variable-direction capacitive displacement sensor based on a corrugated structure according to claim 2, characterized in that, The number of corrugated sheets is several, and they are arranged in a multi-layer nested manner around the axis of the movable electrode (3).

4. A variable-direction capacitive displacement sensor based on a corrugated structure according to claim 3, characterized in that, The corrugated sheet can be integrally formed by stamping or etching.

5. A variable-direction capacitive displacement sensor based on a corrugated structure according to claim 1, characterized in that, The adaptive mechanism includes a flexible angle connecting rod (9) connected to the active electrode (3). A counterweight (6) is provided at one end of the flexible angle connecting rod (9) away from the active electrode (3) via a rotating connecting rod (7). The counterweight (6) is located outside the capacitor shell (5).

6. A variable-direction capacitive displacement sensor based on a corrugated structure according to claim 5, characterized in that, A magnet (8) is provided on the capacitor housing (5), and the magnet (8) can generate a magnetic attraction force on the rotating connecting rod (7).

7. A variable-direction capacitive displacement sensor based on a corrugated structure according to claim 6, characterized in that, When the sensor is placed horizontally, the magnetic attraction force of the magnet (8) is less than the weight of the counterweight (6); When the sensor is placed vertically, the magnetic attraction force of the magnet (8) is greater than the combined force of the rotating connecting rod (7) and the counterweight (6).

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