Non-contact acceleration measurement device and method based on array acoustic levitation

Abstract

The invention discloses a non-contact acceleration measurement device and method based on array acoustic levitation, and belongs to the technical field of non-contact acceleration measurement, the device comprises an ultrasonic levitation phase control array with six array units, the six array units are respectively arranged at the midpoint positions of six surfaces of a virtual cube, and the six surfaces of the virtual cube are respectively provided with an ultrasonic levitation phase control array. Ultrasonic beams emitted by the six array units are focused at the geometric center of the virtual cube; the bearing frame used for supporting the ultrasonic suspension phase control array is installed on a device to be tested. In the movement process, recording each frame of relative displacement of the suspended object relative to the initial position through a high-speed camera; and obtaining the acceleration of the object according to the relative displacement data shot by the high-speed camera. According to the invention, the object is suspended through the acoustic suspension technology, and the displacement of the suspended object generated when the device moves is monitored by using the optical image acquisition technology, so that the accurate measurement of the acceleration is realized, and the accuracy of the acceleration measurement is improved through more efficient sound field modulation and enhanced suspension stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-contact acceleration measurement, and in particular, relates to a non-contact acceleration measurement device and method based on array acoustic suspension. Background Art

[0002] At present, the existing non-contact acceleration measurement devices mainly use magnetic suspension technology, optical suspension technology and electrostatic suspension technology. However, these technical solutions have certain limitations, which restrict their further development.

[0003] 1. Problems with magnetic levitation: Magnetic levitation technology relies on strong magnetic fields to suspend objects. However, strong magnetic fields can interfere with the electronic components of optical cameras, which may cause image distortion when the camera samples and affect the measurement results. At the same time, eddy current heat generation in magnetic levitation technology will increase device power consumption, making it difficult to achieve microsystem integration, thus limiting the miniaturization application of magnetic levitation inertial devices.

[0004] 2. Problems with optical levitation: Optical levitation technology is mainly suitable for objects with smaller mass, and the laser light intensity required for larger objects is too high. In addition, the optical levitation system that achieves precise control of objects is very complex, difficult to operate stably for a long time, and has high costs. In addition, strong lasers may cause problems such as overexposure of the camera, affecting image quality.

[0005] 3. Problems with electrostatic suspension: Electrostatic suspension depends on the charge or conductivity of the object, which limits the types of objects that can be suspended. At the same time, electrostatic suspension is greatly disturbed by the external environment, and any slight external change may affect the measurement results.

[0006] In order to overcome these technical bottlenecks and obtain more accurate acceleration measurements, acoustic levitation technology has gradually become a research hotspot and trend.

[0007] When acoustic levitation technology is applied to the field of acceleration measurement, there is currently an acceleration measurement solution based on near-field acoustic levitation. This solution uses the principle of near-field acoustic levitation to estimate acceleration by observing the change in capacitance between the piezoelectric sheet and the suspended object. However, since this solution is based on near-field acoustic levitation, its acoustic field modulation capability is weak and its suspension stability is poor, making it difficult to meet the needs of high-precision acceleration measurement. Summary of the invention

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide a non-contact acceleration measurement device based on array acoustic levitation, which suspends an object through array acoustic levitation technology and uses optical image acquisition technology to obtain the relative displacement generated when the suspended object moves, and realizes accurate measurement of acceleration through the relationship between relative displacement and acceleration.

[0009] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: In a first aspect, a non-contact acceleration measurement device based on array acoustic levitation is provided, comprising: An ultrasonic suspension phased array, wherein the ultrasonic suspension phased array has six array units, and the six array units are respectively arranged at the midpoints of six faces of a virtual cube, so that the ultrasonic beams emitted by the six array units are focused on the geometric center of the virtual cube; A carrier, the carrier being configured to support the ultrasonic suspension phased array; the carrier being mounted on the device to be tested; The non-contact accelerometer is equipped with a high-speed camera for continuously capturing in real time the image of the suspended object while the non-contact accelerometer is in motion.

[0010] According to a specific embodiment of the present invention, each array unit is a plurality of ultrasonic transducers arranged in a circular array or an N×N square array.

[0011] According to a specific embodiment of the present invention, each array unit is a plurality of ultrasonic transducers arranged in a combination of a circular array and a square array.

[0012] Furthermore, the support frame is composed of two square frames arranged perpendicularly to each other, the side length of the square frame is the same as the side length of the virtual cube, and the two intersection points are respectively located at the midpoints of the two upper and lower opposite faces of the virtual cube.

[0013] According to a specific embodiment of the present invention, the non-contact acceleration measurement device is installed on a slide rail, a mechanical arm or a wheeled robot.

[0014] Through the above-mentioned design scheme, the present invention can bring the following beneficial effects: a non-contact acceleration measurement device and method based on array acoustic suspension is proposed, and an ultrasonic suspension phased array is innovatively designed, wherein the ultrasonic suspension phased array has six array units, and the six array units are respectively arranged at the midpoints of the six faces of the virtual cube, and supported by a carrier frame, and the acceleration is measured through the ultrasonic suspension array. The present invention improves the accuracy of acceleration measurement through more efficient sound field modulation and enhanced suspension stability. In addition, the present invention adopts a more accurate optical image acquisition method in displacement measurement, and uses a high-speed camera to more accurately capture the displacement of the suspended object when the non-contact acceleration measurement device moves, so as to obtain a more accurate acceleration measurement.

[0015] Specifically, the present invention uses array acoustic levitation technology as a suspension solution for contactless measurement. The ultrasonic levitation phased array adopted in this solution can provide acoustic radiation force in multiple directions, improve the stability and control accuracy of the measuring device, and can effectively overcome the defects of other non-contact suspension methods.

[0016] The present invention can suspend a variety of different types of objects. Ultrasonic suspension has strong adaptability to the types of objects, so it can flexibly select suspended objects according to different application scenarios, thereby obtaining more accurate acceleration measurement results.

[0017] The present invention provides a novel ultrasonic suspension phased array structure composed of six array units. The sound field generated by the ultrasonic suspension phased array is jointly generated by the ultrasonic waves emitted by the array units in six directions. Compared with the existing array, the sound field formed by the array can make the suspended object more stable, and has a more flexible modulation scheme, which can achieve more accurate sound field modulation and higher suspension stability.

[0018] The array unit design method in the ultrasonic suspension phased array of the present invention is flexible, and different array structures can be designed according to different application scenarios to achieve modulation of more types of sound fields.

[0019] The present invention has low power consumption and cost, can realize long-term detection, and has the potential for mass production, and is expected to be applied in multiple fields such as medicine and precision instruments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present application. The exemplary embodiments of the present invention and their descriptions are used to understand the present invention and do not constitute improper limitations of the present invention. In the drawings: Figure 1 Schematic diagram of the structure of a non-contact acceleration measurement device based on array acoustic suspension in an embodiment of the present invention; Figure 2 It is a schematic side view of the structure of a non-contact acceleration measurement device based on array acoustic suspension in an embodiment of the present invention; Figure 3 This is a flow chart of acceleration measurement using the non-contact acceleration measurement device based on array acoustic suspension proposed by the present invention; Figure 4 Schematic diagram of the acoustic pressure of ultrasonic suspension phased array; Figure 5 Ultrasonic Levitation Phased Array x Schematic diagram of axial acoustic radiation force; Figure 6 Ultrasonic Levitation Phased Array y Schematic diagram of axial acoustic radiation force; Figure 7 Ultrasonic Levitation Phased Array z Schematic diagram of axial acoustic radiation force; In the figure: 1-array unit; 2-square frame A; 3-square frame B. DETAILED DESCRIPTION

[0021] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical scheme in the present invention is clearly and completely described below in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the present invention is not limited to the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. In order to avoid confusing the essence of the present invention, known methods, processes and flows are not described in detail. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0022] Although acceleration measurement devices based on magnetic levitation, optical levitation and electrostatic levitation technologies can effectively avoid errors caused by mechanical friction and contact, they still have problems such as high system complexity, high cost, poor stability and sensitivity to external interference. Therefore, the present invention selects acoustic levitation technology, which achieves a more stable and controllable sound field by independently controlling each ultrasonic transducer, while having lower power consumption and cost.

[0023] During the acceleration measurement process, the stability of the suspended object is crucial. If the suspension state of the object is unstable, it may cause a large measurement error. In order to improve the stability, the present invention uses the design of focusing the six array units 1 to make the sound field more accurately concentrated at the center of the ultrasonic suspension array, thereby enhancing the stability of the suspended object and ensuring the measurement accuracy during the detection process.

[0024] Acceleration measurement is achieved by capturing the displacement of a suspended object. When the measuring device completes the acceleration measurement of a section of motion, if the suspended object fails to return to the initial position in time, it may cause inaccurate acceleration measurement results in the next section of motion to be measured. In order to solve this problem, the present invention adopts a solution of six array units 1. Each array unit 1 is composed of multiple ultrasonic transducers. After the acceleration detection device measures the acceleration of a section of motion, by adjusting the phase of the array unit 1, an acoustic radiation force can be generated to quickly return the suspended object to the initial suspension position, so that the suspended object can be quickly reset, ensuring the measurement accuracy of the measuring device during continuous motion.

[0025] like Figures 1 to 7As shown, a non-contact acceleration measurement device based on array acoustic suspension includes: an ultrasonic suspension phased array, a carrier and a high-speed camera; the ultrasonic suspension phased array has six array units 1, and the six array units 1 are respectively arranged at the midpoints of the six faces of a virtual cube, so that the ultrasonic beams emitted by the six array units 1 are focused at the geometric center of the virtual cube to form a stable sound field; the carrier is composed of two square frames arranged perpendicularly and crosswise to each other, the side length of the square frame is the same as the side length of the virtual cube, and the two intersection points formed are respectively located at the midpoints of the two faces of the virtual cube facing each other, and the two square frames have the same structure and size, and the two square frames are named square frame A 2 and square frame B 3 respectively. The carrier is installed on the device to be tested to control the non-contact acceleration measurement device to move; the non-contact acceleration measurement device is equipped with a high-speed camera for continuously and in real time capturing the image of the suspended object when the non-contact acceleration measurement device moves, thereby capturing the relative displacement of the suspended object relative to the initial position when the non-contact acceleration measurement device moves. The device to be tested in the present invention refers to the motion device of the acceleration to be measured.

[0026] The present invention proposes an ultrasonic suspension phased array capable of stably suspending an object. Figure 1 and Figure 2 shown. Figure 1 A design scheme is demonstrated using a square array unit as an example. Figure 1 The structure of the ultrasonic suspension phased array and its suspension effect are demonstrated, in which a micro-sphere-type suspension object is placed at the center of the ultrasonic suspension phased array to indicate the suspension position of the device during operation. Figure 2 The side view of the ultrasonically suspended phased array is shown. Figure 1 In the ultrasonic suspension phased array shown in the figure, the six array units 1 facing the center of the ultrasonic suspension phased array can provide acoustic suspension forces in six directions for the suspended object. The multi-directional acoustic suspension forces provided by the ultrasonic suspension phased array can more stably suspend the object in the initial position. When measuring acceleration, the acoustic suspension forces provided in multiple directions can keep the suspended object stable regardless of the direction of the device. This design significantly improves the stability of the suspended object during the measurement process, reduces the error caused by the oscillation of the suspended object in the ultrasonic suspension phased array, and improves the measurement accuracy. In addition, since each array unit 1 can adjust the phase and structure according to needs to obtain a more accurate sound field, the controllability of the measuring device is greatly improved. The hollow design of the ultrasonic suspension phased array also provides more viewing angles for the subsequent optical image acquisition module, namely the high-speed camera, which helps to flexibly adjust the optical image acquisition module to adapt to a wider range of application scenarios. During the movement of the measuring device, the high-speed camera records the displacement of the suspended object relative to the initial position, and estimates the acceleration through the recorded relative displacement information. The overall workflow of the present invention is as follows Figure 3 shown.

[0027] The ultrasonic suspension phased array in the present invention adopts a symmetrical structure. In this embodiment, each array unit 1 is a 2×2 square array, and the initial position of the suspended object is located at the geometric center of the ultrasonic suspension phased array. The ultrasonic suspension phased array in this design generates a sound pressure distribution as shown in FIG. Figure 4 As shown, Figure 4 c represents the suspension position. The initial suspension position is x axis, y Axis and z The acoustic radiation force on the axis is Figure 5 , Figure 6 and Figure 7 As shown. Figure 5 , Figure 6 and Figure 7 It can be seen that x axis, y Axis and z The acoustic radiation force at the axis origin is 0, indicating that the object can be stably suspended at the center of the ultrasonic suspension phased array.

[0028] In the present invention, the type of suspended object selected is a microsphere. At this time, the relationship between the acceleration and the relative displacement of the suspended object can be derived from the following formula. When the measuring device moves along the coordinate axis, the suspended object will have a certain displacement relative to the initial suspension position. Therefore, the motion model of the acoustic suspension system can be established according to the displacement. The model is shown in formula (1).

[0029] (1) in, is the relative displacement between the suspended object and the initial position, is the mass of the suspended object, is the acoustic field stiffness, is the damping coefficient of the accelerometer device, which depends on the medium in the ultrasonic suspension phased array. In the measuring device of the present invention, the damping mainly comes from the viscous resistance of the environment surrounding the suspended object, and the damping coefficient can be expressed as .in is the viscosity coefficient of the light trap environment medium, is the radius of the suspended object. The dynamic characteristic equation of the open-loop array acoustic suspension acceleration measurement device can be written using the traditional second-order transfer function representation, as shown in equation (2).

[0030] (2) in represents the natural frequency of the accelerometer, is the system attenuation coefficient, is the acceleration of the accelerometer relative to the inertial space.

[0031] When the acceleration When the input is a constant, The first and second order differentials of are both zero, It can be expressed by formula (3).

[0032] (3) Transforming equation (3) can obtain the acceleration The formula for obtaining is shown in formula (4).

[0033] (4) In summary, the present invention provides a non-contact acceleration measurement device and method based on array acoustic levitation. The present invention suspends an object through array acoustic levitation technology, and uses optical image acquisition technology to obtain the relative displacement generated when the suspended object moves, and realizes accurate measurement of acceleration through the relationship between relative displacement and acceleration.

[0034] The main innovative features of the present invention are as follows: 1. A non-contact acceleration measurement device based on array acoustic levitation is proposed, which includes six array units 1 arranged at the midpoints of six faces of a virtual cube, and a high-speed camera for capturing the relative displacement of the suspended object when the measuring device moves.

[0035] 2. The proposed ultrasonic suspension phased array structure has the ability to be flexibly adjusted and can be configured according to different needs. Specifically, the number and configuration of the array units 1 can be adjusted according to the requirements of the sound field accuracy. For example, an array composed of more ultrasonic transducers can be used in scenarios with higher accuracy requirements, or a more powerful ultrasonic transducer can be used when a greater suspension force is required. In addition, in order to generate a specific sound field, the structure of each array unit 1 can be adjusted as needed, such as by combining a square array with a circular array.

[0036] 3. The present invention adopts array acoustic levitation technology to measure acceleration. Compared with the existing non-contact measurement technology, it has the advantages of higher stability, flexible sound field adjustment capability, less external interference and lower cost.

[0037] 4. The present invention uses an array form to control the suspension of an object, thereby improving the stability, sound field adjustment capability and measurement accuracy of the acceleration measurement device.

[0038] 5. The present invention adopts a light-acoustic combination scheme and utilizes an optical image acquisition module to record the relative displacement of the suspended object, thereby estimating the acceleration of the object.

[0039] 6. The present invention provides a specific acceleration measurement scheme. The specific steps of the scheme are as follows. First, adjust the phases of the six array units 1 to generate a stable ultrasonic field in the ultrasonic suspension phased array, so that the object is suspended at the center of the ultrasonic suspension phased array; use a high-speed camera to record the initial position of the object suspended in the ultrasonic suspension phased array; then, install the ultrasonic suspension phased array on the device to be tested, and control the device to be tested to move; during the movement, use a high-speed camera to record the relative displacement of each frame of the suspended object relative to the initial position; finally, estimate the acceleration of the object based on the relative displacement data captured by the high-speed camera.

[0040] 7. The shooting position of the high-speed camera is not limited. Due to the special structure of the ultrasonic suspension phased array in the present invention, the high-speed camera can capture the relative displacement of the suspended object from multiple angles. Therefore, the high-speed camera can flexibly control the shooting angle according to different reference backgrounds.

[0041] 8. The ultrasonic suspension phased array structure in the present invention can provide acoustic radiation forces in multiple directions, so the ultrasonic suspension phased array has excellent spatial adaptability. Therefore, the ultrasonic suspension phased array can be applied to the acceleration measurement of various devices to be tested, such as mechanical arms, slide rails and wheeled robots, etc., which greatly expands the application field of the present invention.

Claims

1. A non-contact acceleration measurement device based on array acoustic levitation, characterized in that: include: An ultrasonic suspension phased array, wherein the ultrasonic suspension phased array has six array units, and the six array units are respectively arranged at the midpoints of six faces of a virtual cube, so that the ultrasonic beams emitted by the six array units are focused on the geometric center of the virtual cube; A carrier, the carrier being configured to support the ultrasonic suspension phased array; the carrier being mounted on the device to be tested; The non-contact accelerometer is equipped with a high-speed camera for continuously capturing in real time the image of the suspended object while the non-contact accelerometer is in motion.

2. The non-contact acceleration measurement device based on array acoustic levitation according to claim 1 is characterized in that: Each array unit is a plurality of ultrasonic transducers arranged in a circular array or an N×N square array.

3. The non-contact acceleration measurement device based on array acoustic levitation according to claim 1, characterized in that: Each array unit is a plurality of ultrasonic transducers arranged in a combination of a circular array and a square array.

4. The non-contact acceleration measurement device based on array acoustic levitation according to claim 1, characterized in that: The support frame is composed of two square frames arranged perpendicularly to each other, the side length of the square frame is the same as the side length of the virtual cube, and the two intersection points are respectively located at the midpoints of the two upper and lower opposite faces of the virtual cube.

5. The non-contact acceleration measurement device based on array acoustic levitation according to claim 1, characterized in that: The non-contact acceleration measurement device is mounted on a slide, a robotic arm or a wheeled robot.

6. A method for measuring acceleration using the non-contact acceleration measurement device based on array acoustic levitation according to any one of claims 1 to 5, comprising: Firstly, the phases of the six array units are adjusted to generate a stable ultrasonic field in the ultrasonic suspension phased array, thereby suspending the object at the center of the ultrasonic suspension phased array; the initial position of the object suspended in the ultrasonic suspension phased array is recorded by a high-speed camera; then, the ultrasonic suspension phased array is mounted on the device under test through a carrier, and the device under test is controlled to move; during the movement, the relative displacement of the suspended object relative to the initial position in each frame is recorded by a high-speed camera; finally, the acceleration of the object is obtained based on the relative displacement data captured by the high-speed camera.

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