A cross-type dual-shaft torque sensor

Abstract

The application discloses a cross type double-shaft torque sensor, which comprises a square connecting piece connected with a nano optical cavity and a supporting cantilever arm supporting the square connecting piece; wherein the nano optical cavity comprises a fixed nano optical cavity wall and a movable nano optical cavity wall; the fixed nano optical cavity wall is used for guiding input and output light; when the movable nano optical cavity wall feels external out-of-plane torque, the movable nano optical cavity wall will have out-of-plane displacement relative to the plane; the displacement causes the gap between the movable nano optical cavity wall and the fixed nano optical cavity wall to change, thereby causing the resonance wavelength to be affected; finally, the corresponding force and torque are measured through the linear relationship between the wavelength and the force and the torque.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of torque measurement, and more specifically relates to a cross-type dual-axis torque sensor. BACKGROUND

[0002] Dual-axis torque sensors play an important role in industrial applications, especially in situations where precise control and monitoring of torque is required. With the development of micro-electromechanical systems (MEMS) technology, torque sensors have begun to miniaturize to meet the demand for small-scale torque measurement. This trend has made the application of sensors more widespread and adaptable. In recent years, a variety of new torque sensors have appeared on the market, such as fiber-optic, wireless acoustic surface wave, magnetic-sensitive, and laser-based sensors. These new sensors not only improve measurement accuracy but also expand the application scenarios of torque sensors

[0003] These new sensors, such as fiber-optic, wireless acoustic surface wave, magnetic-sensitive, and laser-based sensors, although they have made technological breakthroughs and improved measurement accuracy and application versatility, still face some technical and practical challenges.

[0004] Magnetic-sensitive sensors are very sensitive to changes in the environmental magnetic field, and any external magnetic interference can affect their measurement accuracy, which limits their application in strong magnetic field environments. Wireless acoustic surface wave sensors are greatly affected by environmental factors such as temperature and humidity, and need to be used in specific environments to perform best. Although new torque sensors have made significant progress in many areas, they still have shortcomings in terms of complex installation and debugging, significant environmental impact, and high cost. Future research and development should focus on solving these problems to better meet market and user needs.

[0005] Nanometer optical cavity torque sensors use advanced optical technology to measure torque by analyzing changes in the phase of light. This change is captured by a photodetector and converted into an electrical signal, which is then analyzed by a data processing system to obtain the torque value. Due to its high sensitivity and accuracy, the nanometer optical cavity torque sensor is very suitable for situations that require precise torque measurement and has demonstrated excellent performance in modern industrial applications. SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art and provide a cross-type dual-axis torque sensor that directly measures torque through the resonance wavelength change of a nanometer optical cavity.

[0007] To achieve the above-mentioned purposes, the present application provides a cross-type dual-axis torque sensor, characterized in that it comprises a square connecting piece connected to a nanometer optical cavity, and a support cantilever arm supporting the square connecting piece.

[0008] The application aims to achieve the following purposes:

[0009] The application is a cross-type double-axis torque sensor, comprising a square connecting piece connected with a nano optical cavity, and a supporting cantilever arm supporting the square connecting piece; wherein the nano optical cavity further comprises a fixed nano optical cavity wall and a movable nano optical cavity wall; the fixed nano optical cavity wall is used for guiding input and output light; when the movable nano optical cavity wall senses an external out-of-plane torque, it will have an out-of-plane displacement relative to the plane, and the displacement will cause the gap between the movable nano optical cavity wall and the fixed nano optical cavity wall to change, thereby affecting the resonance wavelength, and finally the corresponding force and torque are measured through the linear relationship between the wavelength and the force and torque.

[0010] Meanwhile, the application also has the following beneficial effects:

[0011] (1) The cross-type double-axis torque sensor adopts a direct measurement method when measuring torque, has fewer error terms, and is more accurate;

[0012] (2) Compared with the traditional torque sensor, the cross-type double-axis torque sensor has a much smaller size and is more easily used in various small fields;

[0013] (3) The application uses the optical principle to measure the nano beam cavity, which can detect extremely small phase changes, so it is extremely sensitive to torque changes and can achieve very high measurement accuracy;

[0014] (4) The nano beam cavity of the application can work normally in harsh environments such as high temperature and high pressure, and will not lose accuracy due to environmental changes, and is suitable for many fields from automobile manufacturing to aerospace, to mechanical processing, and especially performs well in high-precision equipment testing. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a structural diagram of the cross-type double-axis torque sensor, wherein (a) is a top view, and (b) is a left view;

[0016] Figure 2 is a schematic diagram of the cross-type double-axis torque sensor before and after applying a horizontal torque, wherein (a) is a top view, and (b) is a left view;

[0017] Figure 3 is a schematic diagram of the cross-type double-axis torque sensor before and after applying a vertical torque, wherein (a) is a top view, and (b) is a left view;

[0018] Figure 4 is a mirror pattern schematic diagram;

[0019] Figure 5is a schematic diagram of a manufacturing process of a nano-optical cavity wall. DETAILED DESCRIPTION

[0020] The specific embodiments of the present application will be described below with reference to the accompanying drawings, so that those skilled in the art can better understand the present application. It should be particularly noted that in the following description, when detailed description of known functions and designs may dilute the main content of the present application, these descriptions will be omitted here.

[0021] EMBODIMENT

[0022] Figure 1 is a structural diagram of a cross-type dual-axis torque sensor according to the present application.

[0023] In this embodiment, as shown in Figure 1 (a), the cross-type dual-axis torque sensor according to the present application comprises a square connecting piece connecting the nano-optical cavities, and a supporting cantilever arm supporting the square connecting piece.

[0024] The nano-optical cavities comprise two groups, and the two groups of nano-optical cavities are connected in a vertical manner by the square connecting piece and symmetrically connected around the square connecting piece. As shown in Figure 1 (b), after the two groups of nano-optical cavities are symmetrically connected by the square connecting piece e, the two groups of nano-optical cavities are divided into four segments, denoted as a, b, c, and d, each segment has a length of about 5 um and a width of 600 nm, and the square connecting piece e at the center has a side length of 1800 nm.

[0025] As shown in Figure 1 (b), the nano-optical cavity comprises two layers of nano-optical cavity walls with the same structure, wherein the upper layer is a movable nano-optical cavity wall, and the lower layer is a fixed nano-optical cavity wall.

[0026] The fixed nano-optical cavity wall is used to guide the input and output of light; the movable nano-optical cavity wall is induced to move up and down by physics, thereby changing the gap with the fixed nano-optical cavity wall, so that the resonance wavelength of the nano-optical cavity changes.

[0027] In this embodiment, the movement of the movable nano-optical cavity wall can be induced by various physical measurements, such as the application of torque, as shown in Figure 2 (a), when a horizontal torque M is felt, the horizontal nano-optical cavity wall of the upper layer rotates, as shown in Figure 2(b) shown, so that the vertical direction of the nanometer optical cavity cavity wall tilt, one end close to the lower, one end away from the lower layer, namely: if the nanometer optical cavity cavity wall a and the lower layer of fixed nanometer optical cavity gap becomes smaller, the nanometer optical cavity cavity wall b and the lower layer of fixed nanometer optical cavity gap becomes larger, so that the movable nanometer optical cavity wall mechanical movement changes the gap size between the cavity wall, thereby changing the resonance wavelength of the nanometer optical cavity, finally by measuring the amount of change in the resonance wavelength can be calculated movable nanometer optical cavity wall displacement, thereby measuring the size of the torque.

[0028] For example, as shown in Figure 2 (b), the initial gap between the movable nanometer optical cavity wall 1 and the fixed nanometer optical cavity wall 2 is 300 nm, the relationship between the nanometer optical cavity gap and the resonance wavelength is

[0029] m * λ = 2n c L

[0030] Where m is the diffraction order, λ is the resonance wavelength, n c is the effective refractive index, L is the nanometer optical cavity gap.

[0031] When the torque is felt, the resonance wavelength will change Δλ, and the formula m * Δλ = 2n c ΔL, ΔL can be obtained. Finally, according to the direct linear relationship between the torque size and ΔL, the size of the torque can be calculated.

[0032] Similarly, as shown in Figure 3 When subjected to a vertical torque M, the size of the torque can be measured by the same calculation method.

[0033] In this embodiment, as shown in Figure 4 The nanometer optical cavity wall is symmetrically arranged with a center axis, and the hole shape of the mirror pattern gradually evolves from a circular shape to an elliptical shape. The spacing between adjacent two holes is the same, and each hole on the mirror pattern is similar to a gap. A series of holes with a length of n m from both ends to the center point are collectively referred to as outer holes, and the outer holes form a set of mirrors; a series of holes with a length of n c from the center point to both ends are collectively referred to as inner holes, and the inner holes form an optical cavity supporting optical modes.

[0034] Figure 5 is a schematic diagram of the manufacturing process of the nanometer optical cavity wall.

[0035] In this embodiment, as shown in Figure 5 The nanometer optical cavity wall is manufactured in a 400 nm thick SiN layer above a 500 μm silicon layer. The SBC device is a 1 cm 2The chips are made of Silicon on Insulator (SOI) wafers. They are cut from a 6 inch diameter wafer with a 3 micron thick layer of silicon dioxide (SiO2) and a 220 nanometer thick top layer of silicon (Si). The purpose of the fabrication cycle is to define the pattern of our device on the silicon chip. The standard semiconductor process for silicon is followed through seven major steps: cleaning, resist coating (ZEP 520A), first layer (Si) e-beam lithography, cool down process, silicon etch (transfer of pattern to silicon layer), heated rinsing machine - PG cleaning, undercut (etching of SiO2 using HF to release the device).

[0036] The first step is a standard cleaning procedure that uses sulfuric acid and hydrogen peroxide in a reaction to clean all organic compounds from the chip. A 300-400 nm thick positive photoresist (ZEP 520A) is spun on the chip and then heat cured. The device pattern is written on the resist using e-beam lithography. This is followed by a cold development process to carefully remove the exposed resist. To transfer the pattern from the resist to the silicon device layer, a reactive ion etch step using fluorine chemistry is performed. Finally, the exposed silicon dioxide is etched and the silicon device is released using a wet chemical undercut process with hydrofluoric acid (HF) after the remaining resist is cleaned with a heated Remover-PG.

[0037] Although the foregoing describes illustrative embodiments of the application in sufficient detail to enable those skilled in the art to practice the application, it is to be understood that the variations can be apparent to those skilled in the art, which not specifically defined by the foregoing description. It is to be understood that the foregoing description is not to be in any way limited to the specific embodiments set forth herein, but encompasses all embodiments within the scope of the application as defined in the appended claims.

Claims

1. A cross-type dual-axis torque sensor, characterized in that, include: A square connector for connecting the nano-optical cavity, and a supporting cantilever for supporting the square connector; The nano-optical cavity comprises two sets, which are connected vertically by a square connector and symmetrically connected around the square connector. The nano-optical cavity includes two layers of nano-optical cavity walls with identical structures, wherein the upper layer is a movable nano-optical cavity wall and the lower layer is a fixed nano-optical cavity wall; Among them, the fixed nano-optical cavity wall is used to guide the input and output of light; the movable nano-optical cavity wall is physically induced to move up and down, thereby changing the gap with the fixed nano-optical cavity wall, thus changing the resonant wavelength of the nano-optical cavity. The nano-optical cavity wall is symmetrically arranged with a central axis featuring mirror patterns. The shape of the holes in the mirror patterns gradually evolves from circular to elliptical, with the same spacing between adjacent holes. Each hole in the mirror pattern is similar to a gap, with a length of n from both ends inward. m A series of holes are collectively called external holes, which form a set of reflecting mirrors; the length from the center point to both ends is n. c A series of holes are collectively referred to as internal holes, which form an optical cavity that supports optical modes.

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