Hemispherical double-shaft torque sensor
By using a combination of nanophoton microcavity cantilever and silicon substrate materials in the torque sensor, designing a semi-spherical biaxial torque sensor solves the challenges of existing sensors in nanoscale high-precision measurement and environmental adaptability, achieving high sensitivity and strong adaptability.
Patent Information
- Application Number
- CN202510350052.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2025-06-17
AI Technical Summary
Existing torque sensors have challenges in nanoscale high-precision measurement, environmental adaptability and integration development, and complex structures lead to high manufacturing costs and low adaptability.
A semi-spherical biaxial torque sensor is designed, using nanophoton microcavity cantilever and silicon substrate material, and the combination of vertically connecting beam and nanophoton microcavity cantilever is achieved to achieve high sensitivity detection of torque.
The sensor has high sensitivity, simple structure and strong adaptability, and can detect and measure torque changes more accurately. It is suitable for various robot micro fields and improves the integrated development potential of sensors.
Smart Images
Figure CN120160734A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of torque measurement, and particularly relates to a hemispherical biaxial torque sensor. Background Art
[0002] Torque sensors indirectly measure torque by measuring the deformation or stress generated when an object is subjected to a torque. Micro-miniature torque sensors are advanced instruments for precisely measuring tiny torques. Their core technologies include strain measurement, optical measurement, capacitance measurement, and piezoelectric effect, etc. Combining the application of high-performance elastic materials and nanomaterials, high-precision and miniaturized manufacturing is achieved through micro-electromechanical system technology and precision machining processes. This sensor has wide applications in fields such as robotics, medical devices, aerospace, and precision manufacturing, and can monitor and control torque in real time, improving operation accuracy and safety. However, achieving nanoscale high-precision measurement, enhancing environmental adaptability, and promoting integrated development are still the main technical challenges currently faced. The continuous progress of micro-miniature torque sensors not only drives technological innovation in related fields but also demonstrates important scientific research value and broad application prospects.
[0003] The nano-optical microcavity cantilever is a cutting-edge device that combines nano-photonics and micro-electromechanical system (MEMS) technologies. By integrating an optical microcavity on the cantilever beam, efficient coupling of the optical field and mechanical motion is achieved. Its technical background is based on the light localization and enhancement effects in nano-photonics and the high-sensitivity mechanical characteristics of the cantilever beam in MEMS. The optical microcavity can confine light in an extremely small volume, significantly enhancing the interaction between light and matter, while the cantilever beam can sense weak force or displacement changes. This combination enables the nano-optical microcavity cantilever to exhibit unique advantages in fields such as sensing, optomechanics research, and quantum information processing, such as high-precision mass sensing, force sensing, and acceleration measurement, etc. However, for existing sensors, the manufacturing process requires high-precision nano-processing technologies and appropriate material selection to ensure the high performance and stability of the device. The structure is relatively complex, the manufacturing cost is high, and at the same time, due to the complex structure, the adaptability is low and the sensitivity is poor. Most existing sensor devices use capacitance for measurement. Since the size of the capacitance is large, the sensor structure is thus large and not suitable for the field of micro-robots, such as some biomedical robots. Summary of the Invention
[0004] The object of the present invention is to solve the above problems and provide a hemispherical biaxial torque sensor with high sensitivity, simple structure, convenient use, and strong adaptability.
[0005] To solve the above technical problems, the technical solution of the present invention is: a hemispherical biaxial torque sensor, including a fixed bearing silicon base, a hemispherical torque sensing element, a vertical connecting beam, and a nanophotonic microcavity cantilever. The fixed bearing silicon base is connected to the hemispherical torque sensing element through the vertical connecting beam, and the nanophotonic microcavity cantilever is located on the fixed bearing silicon base and the hemispherical torque sensing element respectively. The nanophotonic microcavity cantilever includes a first nanophotonic microcavity cantilever, a second nanophotonic microcavity cantilever, a third nanophotonic microcavity cantilever, and a fourth nanophotonic microcavity cantilever. The nanophotonic microcavity cantilever located on the fixed bearing silicon base is a fixed microcavity cantilever, and the nanophotonic microcavity cantilever located on the hemispherical torque sensing element is a movable microcavity cantilever. The movable microcavity cantilever can move around the vertical connecting beam together with the hemispherical torque sensing element.
[0006] Preferably, the first nanophotonic microcavity cantilever and the second nanophotonic microcavity cantilever form a group of nanophotonic microcavity cantilevers in the horizontal direction, which detect the torque that causes the hemispherical torque sensing element to change in the horizontal direction. The third nanophotonic microcavity cantilever and the fourth nanophotonic microcavity cantilever form a group of nanophotonic microcavity cantilevers in the vertical direction, which detect the torque that causes the hemispherical torque sensing element to change in the vertical direction.
[0007] Preferably, the movable microcavity cantilever and the fixed microcavity cantilever are mounted on the four ends of the hemispherical torque sensing element and the fixed bearing silicon base through an etching and release process.
[0008] Preferably, the cross-section of the fixed bearing silicon base is a square with a side length of 10 mm, which is used to mount four fixed microcavity cantilever parts in the nanophotonic microcavity cantilever.
[0009] Preferably, the shape of the hemispherical torque sensing element is a standard hemisphere with a radius of 10 mm. The fixed bearing silicon base and the hemispherical torque sensing element are both made of silicon-based wafers of silicon and silicon oxide, and are connected by a vertical connecting beam.
[0010] Preferably, the side length of the vertical connecting beam is 2 mm. The upper side of the vertical connecting beam is in direct contact with the hemispherical torque sensing element, and the hemispherical torque sensing element will deflect accordingly according to the magnitude of the external torque.
[0011] Preferably, the fixed bearing silicon base and the hemispherical torque sensing element are fabricated in a 400 nm thick SiN layer above a 500 μm silicon layer. The fixed bearing silicon base only guides the input and output light, and the movement of the hemispherical torque sensing element can be induced by various physical measurements.
[0012] Preferably, the nano - photonic micro - cavity cantilever is fabricated by removing the SiO2 in the middle region through photolithography technology on the SiO2 layer in the middle of the SOI substrate, and fabricating a silicon micro - mechanical oscillator structure on the top silicon of the rectangular SOI substrate through micro - nano processing technology, while the bottom silicon remains unchanged.
[0013] The beneficial effects of the present invention are as follows:
[0014] 1. The torque sensitivity of the hemispherical biaxial torque sensor provided by the present invention depends on the nano - photonic micro - cavity cantilever. Therefore, it can more accurately detect and measure torque changes and has the characteristic of high sensitivity.
[0015] 2. Compared with the traditional torque sensor, the sensor volume of the hemispherical biaxial torque sensor of the present invention is greatly reduced, and it has better adaptability in various micro - robot fields.
[0016] 3. Since the two pairs of nano - photonic micro - cavity cantilevers are symmetric in structure and form a differential structure, the sensitivity of the sensor is doubled.
[0017] 4. The circular design of the present invention makes the sensor easier to be integrated with various devices and systems, whether it is a robotic arm, a motor or other rotating devices. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 is a front - view and left - view comparison schematic diagram of a hemispherical biaxial torque sensor of the present invention;
[0019] Figure 2 is a top - view of the fixed - type silicon - bearing base of the present invention and a bottom - view comparison schematic diagram of the hemispherical torque - sensing member;
[0020] Figure 3 is a change - comparison schematic diagram of the front - view of the present invention when subjected to torque;
[0021] Figure 4 is a top - view of the nano - photonic micro - cavity cantilever of the present invention and a mirror - pattern comparison schematic diagram.
[0022] Explanation of reference numerals: a, fixed - type silicon - bearing base; b, hemispherical torque - sensing member; c, vertical connecting beam; d, first nano - photonic micro - cavity cantilever; e, second nano - photonic micro - cavity cantilever; f, third nano - photonic micro - cavity cantilever; g, fourth nano - photonic micro - cavity cantilever. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0023] The following further describes the present invention in conjunction with the drawings and specific embodiments:
[0024] As Figures 1 to 4As shown in the figure, a hemispherical biaxial torque sensor provided by the present invention includes a fixed bearing silicon base a, a hemispherical torque sensing member b, a vertical connecting beam c, and a nanophotonic microcavity cantilever. The fixed bearing silicon base a is connected to the hemispherical torque sensing member b through the vertical connecting beam c, and the nanophotonic microcavity cantilever is respectively located on the fixed bearing silicon base a and the hemispherical torque sensing member b. The nanophotonic microcavity cantilever includes a first nanophotonic microcavity cantilever d, a second nanophotonic microcavity cantilever e, a third nanophotonic microcavity cantilever f, and a fourth nanophotonic microcavity cantilever g. The nanophotonic microcavity cantilever located on the fixed bearing silicon base a is a fixed microcavity cantilever, and the nanophotonic microcavity cantilever located on the hemispherical torque sensing member b is a movable microcavity cantilever. The movable microcavity cantilever can move around the vertical connecting beam c together with the hemispherical torque sensing member b.
[0025] As Figure 1 shown, Figure 1 Figure (a) in it is the front view of the present invention, Figure 1 and figure (b) in it is the left view of the present invention. As Figure 2 shown, Figure 2 Figure (a) in it is the schematic structural diagram of the fixed microcavity cantilever, Figure 2 and figure (b) in it is the schematic structural diagram of the movable microcavity cantilever.
[0026] The cross-section of the fixed bearing silicon base a is a square with a side length of 10 mm, which is used to carry four fixed microcavity cantilever parts in the nanophotonic microcavity cantilever.
[0027] The outer shape of the hemispherical torque sensing member b is a standard hemisphere with a radius of 10 mm. Both the fixed bearing silicon base a and the hemispherical torque sensing member b are made of silicon-based wafers of silicon and silicon oxide, and are connected by a vertical connecting beam c.
[0028] The side length of the vertical connecting beam c is 2 mm. The upper side of the vertical connecting beam c is directly in contact with the hemispherical torque sensing member b, and the hemispherical torque sensing member b will deflect accordingly according to the magnitude of the external torque.
[0029] The first nanophotonic microcavity cantilever d and the second nanophotonic microcavity cantilever e form a group of nanophotonic microcavity cantilevers in the horizontal direction, which detect the torque that causes the hemispherical torque sensing member b to change in the horizontal direction. The third nanophotonic microcavity cantilever f and the fourth nanophotonic microcavity cantilever g form a group of nanophotonic microcavity cantilevers in the vertical direction, which detect the torque that causes the hemispherical torque sensing member b to change in the vertical direction. The initial distance between the cavity walls is 500 nm.
[0030] The movable microcavity cantilever and the fixed microcavity cantilever are mounted on the four ends of the hemispherical torque sensing element b and the fixed bearing silicon base a through the etching and release process. In this embodiment, the center of the fixed bearing silicon base a is connected to the vertical connecting beam c, and the hemispherical torque sensing element b will deflect correspondingly according to the magnitude of the external torque. The present invention constitutes a biaxial torque sensor. The movable microcavity cantilever and the fixed microcavity cantilever are mounted on the four ends of the hemispherical torque sensing element and the fixed bearing silicon base through the etching and release process.
[0031] In this embodiment, the etching and release process is an existing mature technology, that is, the existing etching and HF release process.
[0032] The fixed bearing silicon base a and the hemispherical torque sensing element b are fabricated in a 400-nm-thick SiN layer above a 500-μm silicon layer. The fixed bearing silicon base a only guides the input and output light, and the movement of the hemispherical torque sensing element b can be induced by various physical quantities. The physical quantity in this embodiment refers to the physical power provided by an external device, such as torque, etc.
[0033] The nanophotonic microcavity cantilever is fabricated on the SiO2 layer in the middle of the SOI substrate. The middle region of SiO2 is removed by photolithography technology, and a silicon micromachined oscillator structure is fabricated on the top silicon of the rectangular SOI substrate through micro-nano processing technology, while the bottom silicon remains unchanged.
[0034] As Figure 3 shown, Figure 3 Figure (a) in it is a diagram of the sensor of the present invention receiving a torque in the vertical direction, causing a change in the air gap between a pair of nanophotonic microcavity cantilevers in the horizontal direction in the hemispherical torque sensing element b and the fixed bearing silicon base a.
[0035] Figure 3 Figure (b) in it is a diagram of the sensor of the present invention receiving a torque in the direction parallel to the paper surface to the right, causing a change in the air gap between a pair of nanophotonic microcavity cantilevers in the vertical direction in the hemispherical torque sensing element b and the fixed bearing silicon base a. Taking Figure 3 Figure (a) in it as an example, after receiving the torque, the hemispherical torque sensing element b deflects. One end of the left end of the hemispherical torque sensing element b moves upward, and the other end moves downward. The movable cavity walls of the nanophotonic microcavity cantilevers mounted at both ends of it. Therefore, a displacement relative to the fixed microcavity cantilever occurs, resulting in a change in the air gap between the movable microcavity cantilever and the fixed microcavity cantilever in the nanophotonic microcavity cantilever. This causes a change in the resonant wavelength of the laser in the cavity wall gap.
[0036] When there is a torque, due to the existence of the external torque T, the hemispherical torque sensing element b deflects, which will cause displacements of +x and -x at both ends of the hemisphere. The air gaps between it and the base become (100 + x) and (100 - x) respectively, where x is the displacement distance.
[0037] As shown Figure 4 in the figure, it is a top view comparison diagram of the nano-optical cavity cantilever and the mirror pattern. The nano-optical cavity cantilever essentially uses the nano-beam PCC itself, with a width of w = 600 nm, and is split into two independent components through a gap W gap into the first nano-photonic microcavity cantilever d, the second nano-photonic microcavity cantilever e, the third nano-photonic microcavity cantilever f, and the fourth nano-photonic microcavity cantilever g. There are mirror patterns on all four nano-optical cavity cantilevers. The mirror pattern consists of a periodic array of holes whose size gradually tapers from circular to elliptical. Its contour is similar to the gap. The outer holes form a set of mirrors with a length of n1, while the inner holes form an optical cavity that supports the optical mode. The length is n2, and the period a is the distance between two holes.
[0038] The measurement process of a hemispherical biaxial torque sensor of the present invention is analyzed as follows:
[0039] The fixed bearing silicon base a only guides the input and output light, and the movement of the hemispherical torque sensing member b can be induced through various physical measurements. The resonance wavelength of the laser in the nano-photonic microcavity cantilever above it is affected by the mechanical movement of the movable component. In the nano-photonic microcavity cantilever, when the movable microcavity cantilever and the fixed microcavity cantilever are in the original state, the distance between the cavity walls is 500 nm. The relationship between the cavity wall gap of the nano-photonic microcavity cantilever and the resonance wavelength of the laser inside it is m*λ = 2n c L. Where λ is the resonance wavelength, n c is the effective refractive index, and L is the cavity wall gap of the nano-photonic microcavity cantilever.
[0040] When there is an external torque, the hemispherical torque sensing member b deflects. One end of the left end of the hemispherical torque sensing member b moves upward and the other end moves downward, and the movable cavity walls of the nano-photonic microcavity cantilevers carried at both ends. Therefore, a displacement occurs relative to the fixed microcavity cantilever, so that the air gap between the movable microcavity cantilever and the fixed microcavity cantilever in the nano-photonic microcavity cantilever changes, resulting in the resonance wavelength of the laser in the nano-photonic microcavity cantilever being affected. Since the wavelength change has a linear relationship with the displacement change, and the displacement change has a linear relationship with the external torque, the corresponding torque magnitude can be measured by measuring the corresponding wavelength change. The laser and torque in the present invention are generated by existing mature technical equipment.
[0041] In the present invention, whether in the horizontal direction or the vertical direction, the nanophotonic microcavity cantilevers are symmetrically distributed on the hemispherical torque sensing member and the fixed supporting silicon base. When an external torque exists, the deflection of the hemispherical torque sensing member causes the cavity wall gap between the movable microcavity cantilever and the fixed microcavity cantilever of one pair of nanophotonic microcavity cantilevers to decrease, while the cavity wall gap between the movable microcavity cantilever and the fixed microcavity cantilever of the other pair of nanophotonic microcavity cantilevers will increase, and the change amounts of the cavity wall gaps of the two pairs of quantum confinement cavities are the same. Therefore, by detecting the change amount, the sensitivity of the sensor can be improved.
[0042] Those of ordinary skill in the art will realize that the embodiments described herein are for helping the reader understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations that do not depart from the essence of the present invention according to these technical revelations disclosed in the present invention, and these deformations and combinations are still within the protection scope of the present invention.
Claims
1. A hemispherical dual-axis torque sensor, characterized in that: The invention comprises a fixed bearing silicon base (a), a hemispherical torque sensing member (b), a vertical connecting beam (c) and a nanophotonic microcavity cantilever. The fixed bearing silicon base (a) is connected to the hemispherical torque sensing member (b) through the vertical connecting beam (c). The nanophotonic microcavity cantilever is respectively located on the fixed bearing silicon base (a) and the hemispherical torque sensing member (b). The nanophotonic microcavity cantilever comprises a first nanophotonic microcavity cantilever (d), a second nanophotonic microcavity cantilever (e), a third nanophotonic microcavity cantilever (f) and a fourth nanophotonic microcavity cantilever (g). The nanophotonic microcavity cantilever located on the fixed bearing silicon base (a) is a fixed microcavity cantilever. The nanophotonic microcavity cantilever located on the hemispherical torque sensing member (b) is a movable microcavity cantilever. The movable microcavity cantilever can move around the vertical connecting beam (c) together with the hemispherical torque sensing member (b).
2. A hemispherical dual-axis torque sensor according to claim 1, characterized in that: The first nanophoton microcavity cantilever (d) and the second nanophoton microcavity cantilever (e) constitute a group of nanophoton microcavity cantilevers in the horizontal direction, which detect the torque that causes the hemispherical torque sensing element (b) to change in the horizontal direction; the third nanophoton microcavity cantilever (f) and the fourth nanophoton microcavity cantilever (g) constitute a group of nanophoton microcavity cantilever in the vertical direction, which detect the torque that causes the hemispherical torque sensing element (b) to change in the vertical direction.
3. The hemispherical dual-axis torque sensor according to claim 1, characterized in that: The movable microcavity cantilever and the fixed microcavity cantilever are mounted on four ends of the hemispherical torque sensing member (b) and the fixed bearing silicon base (a) through etching and releasing processes.
4. The hemispherical dual-axis torque sensor according to claim 1, characterized in that: The cross section of the fixed bearing silicon base (a) is a square with a side length of 10 mm, and is used to carry four fixed microcavity cantilever parts in the nanophotonic microcavity cantilever.
5. The hemispherical dual-axis torque sensor according to claim 1, characterized in that: The hemispherical torque sensor (b) has a standard hemisphere shape with a radius of 10 mm. The fixed bearing silicon base (a) and the hemispherical torque sensor (b) are both made of silicon and silicon oxide silicon substrates and are connected by a vertical connecting beam (c).
6. The hemispherical dual-axis torque sensor according to claim 1, characterized in that: The side length of the vertical connecting beam (c) is 2 mm, and the upper side of the vertical connecting beam (c) is directly in contact with the hemispherical torque sensing member (b). The hemispherical torque sensing member (b) will deflect accordingly according to the size of the external torque.
7. The hemispherical dual-axis torque sensor according to claim 1, characterized in that: The fixed supporting silicon base (a) and the hemispherical torque sensor (b) are manufactured in a 400nm thick SiN layer above a 500μm silicon layer; the fixed supporting silicon base (a) only guides input and output light, and the movement of the hemispherical torque sensor (b) can be induced by various physical measurements.
8. The hemispherical dual-axis torque sensor according to claim 1, characterized in that: The nanophotonic microcavity cantilever is manufactured by removing SiO2 in the middle area of the SiO2 layer in the middle of the SOI substrate through photolithography technology, and manufacturing a silicon micromechanical oscillator structure on the top silicon of the rectangular SOI substrate through micro-nano processing technology, while the bottom silicon remains unchanged.