Three-component digital accelerometer

Abstract

According to the three-component digital accelerometer, an inclination device fixed to a base is provided with three inclined faces, the included angles between the three inclined faces and the horizontal direction are all 54.7 degrees, and sensitive vibration axes of three quartz accelerometers fixed to the three inclined faces are mutually orthogonal to form a UVW three-dimensional coordinate system; the included angle between the X-axis direction and the Z-axis direction in the XYZ three-dimensional coordinate system is 54.7 degrees; the acquisition module converts the three-component vibration acceleration analog signals corresponding to the U axis, the V axis and the W axis output by the quartz accelerometer into three-component vibration acceleration digital signals corresponding to the U axis, the V axis and the W axis; the signal processing module converts the three-component vibration acceleration digital signals corresponding to the U axis, the V axis and the W axis into three-component vibration acceleration digital signals corresponding to the X axis, the Y axis and the Z axis. The three-component digital accelerometer has the advantages of being simple in structure, easy to implement and maintain and the like while having the good temperature drift characteristic.

Description

Technical Field

[0001] This disclosure relates to the field of vibration observation (such as earthquake observation), and in particular to a three-dimensional digital accelerometer. Background Technology

[0002] In vibration observation techniques (such as seismic observation), it is typically necessary to capture ground ground acceleration in three orthogonal directions (i.e., the X-axis, Y-axis, and Z-axis directions) based on a three-dimensional XYZ coordinate system to facilitate vibration analysis such as seismic intensity assessment (e.g., seismic intensity assessment). Ground acceleration can be captured using accelerometers.

[0003] Traditional force-balanced accelerometers suffer from temperature drift due to the thermal effects of the pendulum elastic system, making them unsuitable for environments with large temperature variations. Quartz accelerometers, on the other hand, offer better temperature drift characteristics and a wider dynamic range, making them more promising. However, quartz accelerometers are typically single-axis vertical structures. Placing them horizontally significantly increases noise (resulting in a substantial decrease in noise performance), severely impacting their normal operation and preventing high-resolution observation of horizontal vibration acceleration.

[0004] How to use quartz accelerometers to observe vibration acceleration in three orthogonal directions based on the XYZ three-dimensional coordinate system with high resolution is a technical problem that deserves attention. Summary of the Invention

[0005] To address the aforementioned technical problems, this disclosure is proposed. Embodiments of this disclosure provide a three-dimensional digital accelerometer.

[0006] According to one aspect of the present disclosure, a three-dimensional digital accelerometer is provided, comprising: a base, a tilting device, three quartz accelerometers, a data acquisition module, and a signal processing module; the base is used to fix the tilting device; the tilting device is used to fix the three quartz accelerometers, the tilting device comprising three tilting surfaces, each tilting surface having an angle of 54.7 degrees with the horizontal direction, the three quartz accelerometers being respectively fixed on the three tilting surfaces, and the sensitive vibration axes of the three quartz accelerometers fixed on the three tilting surfaces being orthogonal to each other to form a UVW three-dimensional coordinate system, and perpendicular to the Z-axis of the XYZ three-dimensional coordinate system. The included angles in all directions are 54.7 degrees. The acquisition module is electrically connected to the three quartz accelerometers respectively, and is used to acquire the three-axis vibration acceleration analog signals corresponding to the U-axis, V-axis and W-axis output by the three quartz accelerometers, and convert the acquired three-axis vibration acceleration analog signals into three-axis vibration acceleration digital signals corresponding to the U-axis, V-axis and W-axis for output. The signal processing module is electrically connected to the acquisition module, and is used to convert and process the three-axis vibration acceleration digital signals corresponding to the U-axis, V-axis and W-axis output by the acquisition module according to the XYZ three-dimensional coordinate system, forming three-axis vibration acceleration digital signals corresponding to the X-axis, Y-axis and Z-axis and outputting them.

[0007] Based on the three-dimensional digital accelerometer provided in the above embodiments of this disclosure, by setting up an inclined device with three inclined surfaces and fixing three quartz accelerometers on the three inclined surfaces of the inclined device, the sensitive vibration axes of the three quartz accelerometers are all in an inclined state. In this way, the projection component of gravity in the direction of the sensitive vibration axis is reduced, that is, the gravity that the quartz accelerometers need to counteract is reduced. Since gravity is an interference term for the sensitive vibration axis, the method of fixing the quartz accelerometers in this disclosure is beneficial to reducing the noise and error of the quartz accelerometers. Since the angle between the three inclined surfaces and the horizontal plane is 54.7 degrees, the sensitive vibration of the three quartz accelerometers fixed on the three inclined surfaces is also reduced. The angle between the axis and the vertical direction is 54.7 degrees, and the sensitive vibration axes of the three quartz accelerometers are orthogonal to each other. This allows gravity to be evenly distributed across the sensitive vibration axes of the three quartz accelerometers, and each sensitive vibration axis needs to cancel out approximately 57.7% of the gravity component. This helps avoid excessive single-axis load and decreased recognition of acceleration signals (i.e., the vertical and horizontal vibration signals can be effectively separated from the signals output by the quartz accelerometers). Using three quartz accelerometers of the same model not only reduces the complexity of signal conversion and processing but also improves the consistency of the accuracy of the final three-dimensional vibration acceleration digital signals. Therefore, the technical solution provided in this disclosure can accurately observe vibration acceleration in three orthogonal directions based on the XYZ three-dimensional coordinate system using quartz accelerometers. This results in a three-dimensional digital accelerometer with good temperature drift characteristics, as well as simple structure, ease of implementation, and ease of maintenance.

[0008] The technical solutions of this disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0009] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the disclosure and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0010] Figure 1 This is a structural block diagram of an embodiment of the three-axis digital accelerometer disclosed herein;

[0011] Figure 2 This is a schematic diagram showing the positional relationship between the UVW three-dimensional coordinate system and the XYZ three-dimensional coordinate system formed by the orthogonal vibration axes of the three quartz accelerometers in the three-dimensional digital accelerometer disclosed herein;

[0012] Figure 3This is a schematic diagram of the structure of an embodiment of the tilting support disclosed herein;

[0013] Figure 4 This is a structural block diagram of an embodiment of the base, tilting bracket, and quartz accelerometer in the triaxial digital accelerometer disclosed herein;

[0014] Figure 5 This is a structural block diagram of another embodiment of the three-axis digital accelerometer disclosed herein. Detailed Implementation

[0015] Example embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. It is obvious that the described embodiments are merely some embodiments of this disclosure, and not all embodiments of this disclosure, and it should be understood that this disclosure is not limited to the example embodiments described herein.

[0016] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this disclosure.

[0017] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of this disclosure are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0018] It should also be understood that in the embodiments disclosed herein, "a plurality of" may refer to two or more, and "at least one" may refer to one, two or more.

[0019] It should also be understood that any component, data or structure mentioned in the embodiments of this disclosure can generally be understood as one or more unless expressly defined or given to the contrary in the context.

[0020] Furthermore, the term "and / or" in this disclosure is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this disclosure generally indicates that the preceding and following related objects have an "or" relationship.

[0021] It should also be understood that the description of the various embodiments in this disclosure emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0022] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0023] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0024] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0026] This disclosure outlines

[0027] In realizing this disclosure, the inventors conducted numerous experiments and discovered that although the noise performance of a quartz accelerometer decreases significantly when placed horizontally, its noise performance does not decrease significantly when tilted, especially when the angle between its sensitive vibration axis and the vertical direction (i.e., the Z-axis direction in the XYZ three-dimensional coordinate system) is 54.7 degrees. The vertical and horizontal vibration signals can be effectively separated from the signal output by the quartz accelerometer. Furthermore, if three quartz accelerometers tilted at the same angle (54.7 degrees) are used, and the sensitive vibration axes of the three quartz accelerometers are orthogonal to each other, and the relationship between the sensitive vibration axes of the three quartz accelerometers and the three coordinate axes in the XYZ three-dimensional coordinate system is clearly defined, then vibration can be observed in the vertical, east-west, and north-south directions while ensuring good temperature drift characteristics and signal dynamic range. This can meet the vibration observation needs in many application scenarios.

[0028] Exemplary Overview

[0029] The three-axis digital accelerometer disclosed herein can be applied to a variety of application scenarios, such as monitoring natural earthquakes and monitoring earthquakes caused by blasting.

[0030] A concrete example is the deployment of three-dimensional digital accelerometers at multiple locations within a seismic zone. Each accelerometer acquires real-time digital vibration acceleration signals in three directions (vertical, east-west, and north-south) based on the XYZ three-dimensional coordinate system at its location. Each accelerometer can locally store the three-dimensional vibration acceleration signals and their acquisition time, and periodically (e.g., daily or weekly) report the currently stored three-dimensional vibration acceleration signals and their acquisition time to the earthquake monitoring platform (e.g., via the internet or satellite). The accelerometer can also report its serial number and location information (e.g., latitude and longitude). In addition, the triaxial digital accelerometer can also determine whether the currently acquired triaxial vibration acceleration digital signal needs to be reported in real time. For example, the triaxial digital accelerometer can determine whether the currently acquired triaxial vibration acceleration digital signal meets the preset requirements (such as exceeding the preset threshold). If the preset requirements are met, the triaxial digital accelerometer should immediately report the currently acquired triaxial vibration acceleration digital signal, its acquisition time, and geographical location information to the earthquake monitoring platform so that the earthquake monitoring platform can promptly learn about abnormal ground vibration phenomena.

[0031] Exemplary embodiments

[0032] The three-axis digital accelerometer disclosed herein refers to an instrument / device / device capable of obtaining digital vibration acceleration signals in three different directions—the X-axis, Y-axis, and Z-axis—of a three-dimensional XYZ coordinate system through measurement and signal processing. The X-axis and Y-axis correspond to the east-west and north-south directions, respectively, while the Z-axis corresponds to the vertical direction. The following describes... Figures 1 to 5 The three-dimensional digital accelerometer disclosed herein will be described.

[0033] like Figures 1 to 5 As shown, the three-axis digital accelerometer disclosed herein mainly includes: a housing (not shown in the figure), a base 100, a tilting device 110, three quartz accelerometers 120, a data acquisition module 130, a signal processing module 140, and a power supply module (not shown in the figure). Additionally, the three-axis digital accelerometer may also include at least one of a storage module 150, a communication module 160, and a display module 170.

[0034] The housing is primarily used to create a space for accommodating components, thus protecting other components in the triaxial digital accelerometer. The housing can house the base 100 and other components together (e.g., the base 100 is not exposed), or it can cooperate with the base 100 to create a space for accommodating other components (e.g., the housing and base 100 are screwed together). The material and shape of the housing can be designed according to actual needs; this disclosure does not limit the material or shape of the housing.

[0035] The base 100 is primarily used to fix the tilting device 110. Additionally, components such as the acquisition module 130, signal processing module 140, storage module 150, communication module 160, and power supply module can also be fixed to the base 100. The base 100 has at least one mounting surface on which components such as the tilting device 110, acquisition module 130, signal processing module 140, storage module 150, communication module 160, and power supply module can all be fixed.

[0036] The base 100 can be cylindrical or cuboid in shape, with its upper surface serving as the mounting surface. When the base 100 has multiple mounting surfaces, components such as the tilting device 110, acquisition module 130, signal processing module 140, storage module 150, communication module 160, and power module can be distributed across these surfaces. For example, the tilting device 110 can be mounted on the upper surface of the cylinder or cuboid, while the acquisition module 130, signal processing module 140, storage module 150, communication module 160, and power module can be mounted on the lower surface. The material and shape of the base 100 can be designed according to actual needs; this disclosure does not limit the material or shape of the base 100.

[0037] The tilting device 110 is mainly used to fix three quartz accelerometers 120. Specifically, the tilting device 110 has three tilting surfaces, and the angle between these three tilting surfaces and the horizontal direction (such as the X-axis or Y-axis direction in the XOY plane) is 54.7 degrees. Due to factors such as errors in the machining of the tilting surfaces, this disclosure allows the angle between the tilting surfaces and the horizontal direction to be 54.7 degrees ± a first error, and the value of the first error is usually small, such as the range of the first error being 0.01 degrees to 0.1 degrees or 0.01 degrees to 0.2 degrees. The three tilting surfaces are usually evenly distributed around a center. For example, the lines connecting the vertical projection points of the same coordinate positions on the three tilting surfaces of the tilting device 110 fixed on the base 100 to the center of the circle form three radii, and the angle between any two of these three radii is 120 degrees. Due to factors such as installation errors of the tilting device 110, this disclosure allows for an error in the included angle between any two of the three radii, specifically, the included angle between any two radii is 120 degrees ± a second error. The value of the second error is typically small, such as ranging from 0.01 degrees to 0.1 degrees or from 0.01 degrees to 0.2 degrees. In a more specific example, the three tilting surfaces can be portions of the three lateral faces of a regular triangular pyramid or a regular triangular frustum.

[0038] Three quartz accelerometers 120 are fixed to the three inclined surfaces of the tilting device 110. The quartz accelerometers 120 are mainly used to monitor the vibration acceleration at their location and output the monitored vibration acceleration signal. The vibration acceleration signal output by the quartz accelerometers 120 is an analog signal, specifically a vibration acceleration analog signal, which is a superimposed analog signal of vertical and horizontal vibration acceleration. Furthermore, the quartz accelerometers 120 in this disclosure can be quartz shear accelerometers or quartz vibrating beam accelerometers with a single sensitive vibration axis, etc.

[0039] In one example, under ideal conditions with no orthogonality error, the sensitive vibration axes of the three quartz accelerometers 120 fixed on three inclined planes can be considered to be perfectly orthogonal to each other, forming a shape as shown in the image. Figure 2 The UVW three-dimensional coordinate system is shown. The orthogonality error here refers to the fact that the sensitive vibration axes of the three quartz accelerometers 120, which should be perpendicular to each other, actually have a deviation of non-90°.

[0040] In another example, under the condition of orthogonality error, the sensitive vibration axes of the three quartz accelerometers 120 fixed on the three inclined planes can be considered to be approximately orthogonal to each other. In this case, the present disclosure can still be used as follows: Figure 2 The UVW three-dimensional coordinate system shown is used to represent this approximately orthogonal situation.

[0041] Figure 2In the UVW three-dimensional coordinate system, the U-axis, V-axis, and W-axis directions represent the directions of the sensitive vibration axes of the three quartz accelerometers 120 fixed on the three inclined surfaces, respectively. The angles between the U-axis, V-axis, and W-axis in the UVW three-dimensional coordinate system and the Z-axis in the XYZ three-dimensional coordinate system are all 54.7 degrees. Due to factors such as machining errors of the inclined surfaces and installation errors (e.g., installation errors of the quartz accelerometers 120 and the inclined device 110), this disclosure allows for errors in the angles between the sensitive vibration axes of the three quartz accelerometers 120 and the Z-axis, specifically 54.7 degrees ± a third error. The value of the third error is typically small, such as ranging from 0.01 degrees to 0.1 degrees or from 0.01 degrees to 0.2 degrees.

[0042] Figure 2 The projections of the U-axis, V-axis, and W-axis onto the horizontal plane (i.e., the XOY plane) form radii OU', OV', and OW' centered at point O, respectively, and the angle between any two of these radii OU', OV', and OW' is 120 degrees. Due to factors such as manufacturing and installation errors, this disclosure allows for a certain error in the angle between any two of the three radii formed by the projections of the sensitive vibration axes of the three quartz accelerometers 120 onto the horizontal plane, specifically, an angle of 120 degrees ± a fourth error. The fourth error is typically small, such as ranging from 0.01 degrees to 0.1 degrees or from 0.01 degrees to 0.2 degrees.

[0043] The acquisition module 130 is electrically connected to each of the three quartz accelerometers 120. This electrical connection refers to a wired connection capable of transmitting signals (such as analog and / or digital signals). The acquisition module 130 is primarily used to acquire the analog vibration acceleration signals corresponding to the U-axis, V-axis, and W-axis outputs from the three quartz accelerometers 120. The acquisition module 130 also converts the acquired three-channel analog vibration acceleration signals into corresponding digital vibration acceleration signals for the U-axis, V-axis, and W-axis, and outputs them. Therefore, the acquisition module 130 not only has analog signal acquisition capabilities but also analog-to-digital conversion capabilities. Thus, the acquisition module 130 includes circuit units such as an analog signal acquisition circuit and an analog-to-digital conversion circuit. By using the acquisition module 130 to convert the three-channel analog vibration acceleration signals into corresponding digital vibration acceleration signals for the U-axis, V-axis, and W-axis, and providing them to the signal processing module 140, the signal processing module 140 can easily process the digital signals.

[0044] The signal processing module 140 is electrically connected to the acquisition module 130. This electrical connection refers to a wired connection capable of transmitting signals (such as analog and / or digital signals). The signal processing module 140 primarily converts the digital vibration acceleration signals corresponding to the U, V, and W axes output by the acquisition module 130 according to the XYZ three-dimensional coordinate system, thereby generating digital vibration acceleration signals corresponding to the X, Y, and Z axes, which are then output. In other words, the signal processing module 140 has a coordinate system conversion function for digital signals. Furthermore, if the aforementioned errors exist, the signal processing module 140 can perform error correction processing simultaneously with the conversion processing to eliminate the impact of errors on the accuracy of the monitoring results.

[0045] The power module provides power to the electrical components in the triaxial digital accelerometer, such as the acquisition module 130, signal processing module 140, and display module 170. The power module can provide power to the electrical components via an external power supply or by utilizing the internal battery of the triaxial digital accelerometer. This disclosure does not limit the specific implementation of the power module.

[0046] In one example, such as Figure 3 and Figure 4 As shown, the tilting device 110 of this disclosure may include: three tilting supports 1101, each tilting support 1101 mainly including: a first support plate 11011, a second support plate 11012, and at least one fixing member ( Figure 3 and Figure 4 (Neither shown in the image). The first support plate 11011 and the second support plate 11012 are formed as follows: Figure 3 and Figure 4 The L-shaped bracket shown has an included angle of 54.7 degrees between the first support plate 11011 and the second support plate 11012 (this disclosure allows for the aforementioned first error in the included angle between the two). The first support plate 11011 is horizontally fixed to the upper surface of the base 100 (e.g., fixed to the upper surface of the base 100 by means of adhesive or screwing), the outer surface of the second support plate 11012 forms an inclined surface 110121, and the second support plate 11012 is provided with at least one fixing hole 110122 (e.g., ...). Figure 3 and Figure 4The second support plate 11012 has three fixing holes 110122. The quartz accelerometer 120 is fixed to the tilt bracket 1101 by the cooperation of the fixing parts with the fixing holes 110122. For example, the three fixing holes 110122 are threaded holes with internal threads, and the three fixing parts are screws. The three screws pass through the three through holes on the quartz accelerometer 120 and are screwed into the corresponding threaded holes on the second support plate 11012, so that the quartz accelerometer 120 is fixed on the tilt surface 110121 of the tilt bracket 1101. Alternatively, the tilting device 110 of this disclosure can also be in other forms. For example, the tilting device 110 can be a regular triangular pyramid or a regular triangular frustum. The bottom surface of the regular triangular pyramid / frustum is fixedly connected to the upper surface of the base 100 (e.g., fixed to the upper surface of the base 100 by means of adhesive or screw). The three sides of the regular triangular pyramid / frustum each have an angle of 54.7 degrees with the horizontal direction (this disclosure allows for the aforementioned first error in the angle between the sides and the horizontal direction). Each of the three sides of the regular triangular pyramid / frustum is provided with multiple fixing holes. The three quartz accelerometers 120 are fixed to the three sides respectively by the cooperation of the fixing parts and the fixing holes.

[0047] The tilting device 110 is implemented using three independent tilting supports 1101, making each tilting support 1101 and the quartz accelerometer 120 fixed on it an independent unit. The installation, adjustment, and replacement of one independent unit will not affect the others. This not only facilitates the orthogonality of the sensitive vibration axes of the three quartz accelerometers 120 but also makes the maintenance and debugging of the tilting device 110 and the quartz accelerometers 120 more convenient and efficient. Furthermore, the tilting support 1101 has a simple structure and is easy to manufacture. Additionally, the area enclosed by the three tilting supports 1101 can be used to house other components, allowing for effective control of the overall size of the triaxial digital accelerometer.

[0048] In one embodiment, the projection points of the same coordinate positions (such as the center of gravity of the three tilting supports 1101) on the upper surface of the base 100 form an equilateral triangle (hereinafter referred to as the first equilateral triangle), and the first equilateral triangle can be considered as an inscribed equilateral triangle of a circle (hereinafter referred to as the first circumcircle). In this way, when the three quartz accelerometers 120 are installed in the same position on the three tilting supports 1101, the three quartz accelerometers 120 fixed on the three tilting supports 1101 are evenly distributed on a circumference of the upper surface of the base 100, and the circumference is concentric with the first circumcircle. In other words, the projection points of the same coordinate positions on the three quartz accelerometers 120 (such as the center point of the quartz accelerometer 120) onto the base 100 form an equilateral triangle (hereinafter referred to as the second equilateral triangle), and this second equilateral triangle can be considered as an inscribed equilateral triangle of a circle (hereinafter referred to as the second circumcircle). The first circumcircle and the second circumcircle are concentric circles, and the line connecting the projection points of the center points of the three quartz accelerometers 120 onto the upper surface of the base 100 and the center of the second circumcircle is the radius of the second circumcircle. The included angle between any two of these three radii is 120 degrees (this disclosure allows for a certain error between the included angle between any two of the three radii and 120 degrees).

[0049] In a more specific example, the base 100 is a cylinder, that is, the upper surface of the base 100 is circular. The first circumcircle of the equilateral triangle formed by the projection points of the center points of the three inclined supports 1101 onto the upper surface of the base 100 is concentric with the upper surface of the base 100. The second circumcircle of the equilateral triangle formed by the projection points of the center points of the three quartz accelerometers 120 onto the upper surface of the base 100 is also concentric with the upper surface of the base 100. The radii of the first circumcircle and the second circumcircle can be the same or different.

[0050] By projecting the same coordinate points on the three tilting supports 1101 onto the upper surface of the base 100 to form an equilateral triangle, the positioning and installation of the three tilting supports 1101 are facilitated. By evenly distributing the three quartz accelerometers 120 fixed on the tilting supports 1101 on a circumference, the positioning and installation of the three quartz accelerometers 120 are facilitated, and the sensitive vibration axes of the three quartz accelerometers 120 are made orthogonal to each other. This simplifies the assembly and maintenance of the three-dimensional digital accelerometer.

[0051] In one example, the acquisition module 130 and signal processing module 140 of this disclosure can also be fixedly mounted on the base 100. For example, both the acquisition module 130 and signal processing module 140 can be fixed on the upper surface of the base 100, or both can be fixed on the lower surface of the base 100. When the acquisition module 130 and signal processing module 140 are fixed on the upper surface of the base 100, they can be fixed within the area enclosed by the three inclined supports 1101, i.e., within the circumferential area of ​​the first circumscribed circle. This makes the structure of the triaxial digital accelerometer more compact, and the three inclined supports 1101 can separate the quartz accelerometer 120 from other components, thus avoiding the influence of other components on the quartz accelerometer 120 and improving the monitoring performance of the triaxial digital accelerometer.

[0052] In one example, the sensitive vibration axes of the three quartz accelerometers 120 disclosed herein each correspond to a coordinate axis in the UVW three-dimensional coordinate system (when there is no orthogonality error in the sensitive vibration axes of the three quartz accelerometers 120, the sensitive vibration axes of the three quartz accelerometers 120 are the three coordinate axes in the UVW three-dimensional coordinate system). Specifically, as shown in... Figure 2 As shown, the projection of the quartz accelerometer 120 corresponding to the sensitive vibration axis and the U-axis on the horizontal plane is opposite to the X-axis in the XYZ three-dimensional coordinate system. The projection of the quartz accelerometer 120 corresponding to the sensitive vibration axis and the V-axis on the horizontal plane makes an angle of 30 degrees with the Y-axis in the XYZ three-dimensional coordinate system. The projection of the quartz accelerometer 120 corresponding to the sensitive vibration axis and the W-axis on the horizontal plane makes an angle of 150 degrees with the Y-axis in the XYZ three-dimensional coordinate system. By correspondingly positioning the sensitive vibration axes of each quartz accelerometer 120 with the coordinate axes in the UVW three-dimensional coordinate system and the XYZ three-dimensional coordinate system, it is not only beneficial to clarify the layout of the three-dimensional digital accelerometers and effectively distinguish the monitoring results of the three quartz accelerometers 120, but also to simplify signal conversion and processing, thereby facilitating the convenient and accurate acquisition of the three-dimensional digital acceleration monitoring results.

[0053] In one example, the acquisition module 130 of this disclosure includes three differential acquisition circuits 1301. The input terminals of the three differential acquisition circuits 1301 are all analog signal input terminals, and the output terminals of the three differential acquisition circuits 1301 are all digital signal output terminals. The input terminal of each differential acquisition circuit 1301 is electrically connected to the output terminal of a quartz accelerometer 120, thereby allowing the analog vibration acceleration signals (such as current signals) corresponding to the U-axis, V-axis, and W-axis generated by the three quartz accelerometers 120 to enter the three differential acquisition circuits 1301 respectively. Each of the three differential acquisition circuits 1301 converts the received analog vibration acceleration signals into digital vibration acceleration signals, thereby forming digital vibration acceleration signals corresponding to the U-axis, V-axis, and W-axis, and outputting them. By utilizing the three-channel differential acquisition circuit 1301 to implement the acquisition module 130, common-mode noise such as power line interference and environmental electromagnetic interference can be eliminated, thereby greatly reducing the impact of noise on the effective signal and achieving the purpose of suppressing interference. In this way, the weak vibration acceleration signal output by the quartz accelerometer 120 can also be accurately captured, which in turn helps to improve the signal accuracy and dynamic range of the three-dimensional digital accelerometer, making the digital accelerometer better adaptable to high-precision measurement scenarios.

[0054] In one example, the signal processing module 140 of this disclosure may include a microprocessor such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or a MCU (Microcontroller Unit). The three input terminals of the signal processing module 140 are electrically connected to the three output terminals of the three differential acquisition circuits 1301, thereby allowing the digital vibration acceleration signals (such as level signals) corresponding to the U-axis, V-axis, and W-axis generated by the three differential acquisition circuits 1301 to enter the signal processing module 140. The signal processing module 140 performs signal conversion processing on the received digital vibration acceleration signals corresponding to the U-axis, V-axis, and W-axis. The signal conversion processing performed by the signal processing module 140 may include not only coordinate system transformation processing of the received digital vibration acceleration signals, but also error correction processing. Error correction processing may include at least one of the following: correction processing for orthogonality error (i.e., orthogonality error of the sensitive vibration axes of the three quartz accelerometers 120) and correction processing for the sensitivity of the quartz accelerometers.

[0055] In one example, the coordinate system transformation process performed by the signal processing module 140 of this disclosure can be specifically as follows: the signal processing module 140 takes the received triaxial vibration acceleration digital signals corresponding to the U-axis, V-axis, and W-axis as a three-dimensional vector, and multiplies this three-dimensional vector with a pre-stored first transformation matrix to obtain a three-dimensional vector (i.e., the first three-dimensional vector). The three elements in the first three-dimensional vector are the triaxial vibration acceleration digital signals corresponding to the X-axis, Y-axis, and Z-axis. The aforementioned first transformation matrix is ​​a 3*3 matrix, and the values ​​of the nine elements in the first transformation matrix are set according to 54.7 degrees (such as the cosine value of 54.7 degrees, etc.), that is, each element in the first transformation matrix is ​​set according to the relative rotation angle (i.e., 54.7 degrees) between the two three-dimensional coordinate systems.

[0056] In one example, the signal processing module 140 of this disclosure can obtain the first three-dimensional vector by the following formula (1):

[0057] Formula (1)

[0058] In the above formula (1), the first three-dimensional vector In This represents the digital signal of vibration acceleration corresponding to the X-axis direction. This represents the digital signal of vibration acceleration corresponding to the Y-axis direction. This represents the digital signal of vibration acceleration along the Z-axis, a three-dimensional vector. In This represents the digital signal of vibration acceleration corresponding to the U-axis direction. This represents the digital signal of vibration acceleration corresponding to the V-axis direction. This represents the digital signal of vibration acceleration corresponding to the W-axis direction. This represents the first transformation matrix.

[0059] The aforementioned first transformation matrix The methods for obtaining this include: the unit vector of the U-axis is The unit vector of the V-axis is The unit vector of the W-axis is The first transformation matrix is ​​obtained by transposing the 3*3 matrix formed by the three unit vectors.

[0060] This disclosure employs a data acquisition module 130 to convert the three-axis vibration acceleration analog signal into a three-axis vibration acceleration digital signal, which is then provided to a signal processing module 140. The signal processing module 140 uses a first transformation matrix to convert the three-axis vibration acceleration digital signals corresponding to the U-axis, V-axis, and W-axis into three-axis vibration acceleration digital signals corresponding to the X-axis, Y-axis, and Z-axis in the digital domain. This avoids the circuit complexity and additional circuit noise introduced by using operational amplifiers, adders, and other circuits in analog circuits to perform multiplication and addition operations to synthesize the three-axis vibration acceleration analog signals corresponding to the X-axis, Y-axis, and Z-axis. This not only simplifies the implementation of the circuit complexity but also reduces noise interference and improves the accuracy of vibration acceleration monitoring results.

[0061] In one example, the coordinate system transformation and error correction processes performed by the signal processing module 140 of this disclosure can be specifically as follows: The signal processing module 140 takes the received triaxial vibration acceleration digital signals corresponding to the U-axis, V-axis, and W-axis as a three-dimensional vector, and multiplies this three-dimensional vector with a pre-stored second transformation matrix to obtain a three-dimensional vector (i.e., the second three-dimensional vector). The three elements in this second three-dimensional vector are the triaxial vibration acceleration digital signals corresponding to the X-axis, Y-axis, and Z-axis. The aforementioned second transformation matrix is ​​a 3*3 matrix, and the values ​​of the nine elements in the second transformation matrix are set based on 54.7 degrees (such as the cosine value of 54.7 degrees), the sensitivity error of the quartz accelerometer 120, and the orthogonality error of the sensitive vibration axes of the three quartz accelerometers 120. That is, each element in the second transformation matrix is ​​set based on the relative rotation angle (i.e., 54.7 degrees) between the two three-dimensional coordinate systems and various errors.

[0062] In one example, the signal processing module 140 of this disclosure can obtain the second three-dimensional vector by the following formula (2):

[0063] Formula (2)

[0064] In the above formula (2), the second three-dimensional vector In This represents the digital signal of vibration acceleration corresponding to the X-axis direction. This represents the digital signal of vibration acceleration corresponding to the Y-axis direction. This represents the digital signal of vibration acceleration along the Z-axis, a three-dimensional vector. In This represents the digital signal of vibration acceleration corresponding to the U-axis direction. This represents the digital signal of vibration acceleration corresponding to the V-axis direction. This represents the digital signal of vibration acceleration corresponding to the W-axis direction. This represents the second transformation matrix. The elements a1, a2, a3, b1, b2, b3, c1, c2, and c3 in the second transformation matrix can be obtained by comparing with a standard quartz accelerometer (such as a quartz accelerometer that has undergone metrological verification), or by testing on an absolute calibration platform. For example, by comparing the three quartz accelerometers 120 in the three-dimensional digital accelerometer with a standard quartz accelerometer, the sensitivity error and orthogonality error of the three quartz accelerometers 120 can be obtained. By adjusting the corresponding elements in the first transformation matrix using the sensitivity error and orthogonality error, the second transformation matrix can be obtained.

[0065] This disclosure uses an acquisition module 130 to convert the three-axis vibration acceleration analog signal into a three-axis vibration acceleration digital signal, which is then provided to the signal processing module 140. The signal processing module 140 uses a second transformation matrix to convert the three-axis vibration acceleration digital signals corresponding to the U-axis, V-axis, and W-axis into three-axis vibration acceleration digital signals corresponding to the X-axis, Y-axis, and Z-axis in the digital domain. This not only avoids the problem of large orthogonal errors and large sensitivity errors that are difficult to eliminate using analog circuits (e.g., this disclosure can achieve a sensitivity of 0.01% for the three-axis digital accelerometer and reduce its orthogonal error to less than 0.1%), but also avoids the circuit complexity and additional circuit noise introduced by using operational amplifiers, adders, and other circuits in analog circuits to perform multiplication and addition operations to synthesize the three-axis vibration acceleration analog signals corresponding to the X-axis, Y-axis, and Z-axis. Therefore, it not only helps to reduce the impact of errors on the accuracy of vibration acceleration monitoring, but also simplifies the implementation of circuit complexity, reduces noise interference, and thus helps to ensure the accuracy of vibration acceleration monitoring results of the three-axis digital accelerometer.

[0066] In one example, the storage module 150 of this disclosure is electrically connected to the signal processing module 140, and the storage module 150 is mainly used to perform corresponding data read / write operations according to the read / write requests transmitted from the signal processing module 140. For example, according to the write request from the signal processing module 140, the storage module 150 stores the corresponding three-axis vibration acceleration digital signals of the X, Y, and Z axes transmitted by the signal processing module 140 in the corresponding storage addresses, thereby realizing local storage of monitoring results. As another example, according to the read request from the signal processing module 140, the storage module 150 provides the corresponding three-axis vibration acceleration digital signals of the X, Y, and Z axes stored in the corresponding storage addresses to the signal processing module 140, so that the signal processing module 140 can output the locally stored monitoring results, such as transmitting them to an external device. In addition, the storage module 150 can also be used to store information such as the corresponding three-axis vibration acceleration digital signals of the U, V, and W axes, a first transformation matrix, and a second transformation matrix. The storage module 150 may include a memory card such as a flash memory chip.

[0067] In one example, the communication module 160 of this disclosure is electrically connected to the signal processing module 140, and the communication module 160 is mainly used to perform information interaction operations with external devices according to the signal receiving / transmitting requirements transmitted by the signal processing module 140. For example, according to the transmitting control of the signal processing module 140, the communication module 160 transmits the three-axis vibration acceleration digital signals corresponding to the X, Y, and Z axes to external devices (such as external devices on the Internet or point-to-point connected external devices); as another example, according to the receiving control of the signal processing module 140, the communication module 160 transmits requests or commands sent by external devices to the signal processing module 140. When the three-axis digital accelerometer does not need to locally store the three-axis vibration acceleration digital signals corresponding to the X, Y, and Z axes, the signal processing module 140 can directly transmit the currently obtained three-axis vibration acceleration digital signals corresponding to the X, Y, and Z axes to the external devices through the communication module 160.

[0068] In one example, the communication module 160 of this disclosure may include at least one of an internet-based network interface and a short-range point-to-point communication interface. The internet-based network interface may include an RJ45 interface, a fiber optic interface, and a Wi-Fi interface, etc. The short-range point-to-point communication interface may include a Bluetooth interface, a USB (Universal Serial Bus) interface, and a serial port (such as a UART (Universal Asynchronous Receiver / Transmitter), etc. External devices can remotely access the triaxial digital accelerometer via the internet-based network interface to obtain the triaxial vibration acceleration digital signals corresponding to the X, Y, and Z axes, either locally stored or monitored in real time by the triaxial digital accelerometer. External devices can establish a signal connection with the triaxial digital accelerometer via the short-range point-to-point communication interface, and obtain the triaxial vibration acceleration digital signals corresponding to the X, Y, and Z axes, either locally stored or monitored in real time by the triaxial digital accelerometer, through this signal connection.

[0069] The display module 170 is electrically connected to the signal processing module 140. The display module 170 is mainly used to display corresponding information according to the control of the signal processing module 140. For example, under the control of the signal processing module 140, the display module 170 can display waveforms of the three-axis vibration acceleration digital signals corresponding to the X, Y, and Z axes in real time. Another example is that, under the control of the signal processing module 140, the display module 170 can display the working status of the three-axis digital accelerometer and whether any abnormalities have occurred. The display module 170 may include an LED (light-emitting diode) based display module or an OLED (organic light-emitting diode) based display module, etc.

[0070] This disclosure, by setting up a storage module 150, a communication module 160, and a display module 170, especially an Internet-based network interface and a short-range point-to-point communication interface, not only allows the vibration acceleration monitoring platform and external devices such as local access devices to access the monitoring results of the three-dimensional digital accelerometer at any time, but also enables the three-dimensional digital accelerometer to support functions such as timed reporting of monitoring results and real-time display of monitoring results, thereby making the implementation of vibration acceleration monitoring more flexible and diverse.

[0071] Exemplary three-axis digital accelerometer

[0072] The following is for reference. Figure 5 To describe a three-axis digital accelerometer according to an embodiment of the present disclosure. Figure 5 A block diagram of a three-axis digital accelerometer according to an embodiment of the present disclosure is shown. Figure 5 As shown, the three-way digital accelerometer includes: three quartz accelerometers 120, three-channel differential acquisition circuit 1301, CPU 1401, SD (Secure Digital Memory) memory card 1501, network interface 1601 (including MAC (Media Access Control Address)), UART 1602, OLED 1701, and clock circuit 180, etc.

[0073] Three quartz accelerometers 120 are tilted via three tilting supports 1101, and the sensitive vibration axes of the three quartz accelerometers 120 are orthogonal to each other, forming a shape as shown. Figure 2 The UVW three-dimensional coordinate system is shown.

[0074] The three-channel differential acquisition circuit 1301 converts the analog vibration acceleration signals of the three quartz accelerometers 120 corresponding to the U-axis, V-axis and W-axis into digital vibration acceleration signals of the three quartz accelerometers 120, and provides them to the CPU 1401.

[0075] CPU1401 has data processing and instruction execution capabilities, and can control components such as SD memory card 1501, network interface 1601, UART 1602, OLED 1701 and clock circuit 180 in the three-way digital accelerometer to perform the desired functions.

[0076] The SD memory card 1501 can store one or more computer program instructions and corresponding three-axis vibration acceleration digital signals DENG along the X, Y, and Z axes. The CPU 1401 can execute the computer program instructions to realize the coordinate system transformation, error correction, read / write control, communication control (such as communication control based on MAC and network interface 1601 and communication control via UART 1602), display control (such as display control based on OLED 1701), and / or other desired functions as described above.

[0077] The clock circuit 180 is a synchronous metronome for the CPU 1401 to execute instructions, and the clock circuit 180 may include: a crystal oscillator and a clock chip (PLL phase-locked loop), etc. For example, the clock circuit 180 can multiply the low-frequency signal of the crystal oscillator to the high-frequency signal required by the CPU 1401, and the clock circuit 180 can also support dynamic frequency adjustment to provide the CPU 1401 with a signal of the corresponding frequency when the CPU 1401 is in power-saving mode.

[0078] Of course, for the sake of simplicity, Figure 5 Only some of the components of this triaxial digital accelerometer relevant to this disclosure are shown, omitting components such as buses, input / output interfaces, etc. In addition, the triaxial digital accelerometer may include any other suitable components depending on the specific application.

Claims

1. A three-dimensional digital accelerometer, characterized in that, The three-dimensional digital accelerometer includes: a base, a tilting device, three quartz accelerometers, a data acquisition module, and a signal processing module; The base is used to fix the tilting device; The tilting device is used to fix the three quartz accelerometers. The tilting device includes three tilting surfaces, each with an angle of 54.7 degrees to the horizontal direction. The three quartz accelerometers are respectively fixed on the three tilting surfaces, and the sensitive vibration axes of the three quartz accelerometers fixed on the three tilting surfaces are orthogonal to each other to form a UVW three-dimensional coordinate system, with an angle of 54.7 degrees to the Z-axis direction in the XYZ three-dimensional coordinate system. The acquisition module is electrically connected to the three quartz accelerometers respectively, and is used to acquire the three-axis vibration acceleration analog signals output by the three quartz accelerometers corresponding to the U-axis, V-axis and W-axis, and convert the acquired three-axis vibration acceleration analog signals into three-axis vibration acceleration digital signals corresponding to the U-axis, V-axis and W-axis for output. The signal processing module is electrically connected to the acquisition module. The signal processing module is used to convert and process the three-dimensional vibration acceleration digital signals output by the acquisition module according to the XYZ three-dimensional coordinate system, corresponding to the U-axis, V-axis and W-axis, to form three-dimensional vibration acceleration digital signals corresponding to the X-axis, Y-axis and Z-axis, and then output them.

2. The three-dimensional digital accelerometer according to claim 1, characterized in that, The tilting device includes three tilting brackets, each tilting bracket including a first support plate, a second support plate, and at least one fixing member, wherein the first support plate and the second support plate form an L-shaped bracket with an included angle of 54.7 degrees. The first support plate is fixed to the upper surface of the base, the outer surface of the second support plate is the inclined surface, and at least one fixing hole is provided on the second support plate. The quartz accelerometer is fixed to the inclined bracket by the cooperation of the fixing member with the fixing hole.

3. The triaxial digital accelerometer according to claim 2, characterized in that, The projections of the same coordinate points on the three inclined supports onto the upper surface of the base form an equilateral triangle, and the three quartz accelerometers fixed on the three inclined supports are evenly distributed on a circumference of the upper surface of the base, with the circumference and the circumcircle of the equilateral triangle being concentric circles.

4. The triaxial digital accelerometer according to claim 3, characterized in that, Both the acquisition module and the signal processing module are fixedly mounted on the base, and are located within the area enclosed by the three inclined supports.

5. The triaxial digital accelerometer according to claim 1, characterized in that, The projection of the quartz accelerometer corresponding to the sensitive vibration axis and the U-axis onto the horizontal plane is opposite to that of the X-axis. The projection of the quartz accelerometer corresponding to the sensitive vibration axis and the V-axis onto the horizontal plane forms an angle of 30 degrees with the Y-axis. The projection of the quartz accelerometer corresponding to the sensitive vibration axis and the W-axis onto the horizontal plane forms an angle of 150 degrees with the Y-axis.

6. The triaxial digital accelerometer according to any one of claims 1 to 5, characterized in that, The acquisition module includes three differential acquisition circuits. The output terminals of the three quartz accelerometers are electrically connected to the input terminals of the three differential acquisition circuits. The three differential acquisition circuits are used to acquire the three-axis vibration acceleration analog signals output by the three quartz accelerometers, corresponding to the U-axis, V-axis, and W-axis, and convert the acquired three-axis vibration acceleration analog signals into three-axis vibration acceleration digital signals corresponding to the U-axis, V-axis, and W-axis, and output them.

7. The triaxial digital accelerometer according to claim 6, characterized in that, The three input terminals of the signal processing module are electrically connected to the output terminals of the three differential acquisition circuits, respectively. The signal processing module is specifically used to: multiply the first three-dimensional vector formed by the three-dimensional vibration acceleration digital signals of the corresponding U-axis, V-axis and W-axis with the first transformation matrix to obtain the second three-dimensional vector, and use the three elements contained in the second three-dimensional vector as the three-dimensional vibration acceleration digital signals of the corresponding X-axis, Y-axis and Z-axis. The first transformation matrix is ​​a 3*3 matrix, and the values ​​of the elements in the first transformation matrix are set according to 54.7 degrees.

8. The triaxial digital accelerometer according to claim 6, characterized in that, The three input terminals of the signal processing module are electrically connected to the output terminals of the three differential acquisition circuits, respectively. The signal processing module is specifically used to: multiply the first three-dimensional vector formed by the three-dimensional vibration acceleration digital signals of the U-axis, V-axis and W-axis with the second transformation matrix to obtain the third three-dimensional vector, and use the three elements contained in the third three-dimensional vector as the corresponding three-dimensional vibration acceleration digital signals of the X-axis, Y-axis and Z-axis. The second transformation matrix is ​​a 3*3 matrix, and the values ​​of the elements in the second transformation matrix are set based on 54.7 degrees, the sensitivity error of the quartz accelerometer, and the orthogonality error of the sensitive vibration axes of the three quartz accelerometers.

9. The triaxial digital accelerometer according to any one of claims 1 to 5, characterized in that, The three-dimensional digital accelerometer further includes at least one of a storage module, a communication module, and a display module; The storage module is electrically connected to the signal processing module. The storage module is used to output / write the corresponding three-axis vibration acceleration digital signals of the X-axis, Y-axis and Z-axis according to the read / write control of the signal processing module. The communication module is electrically connected to the signal processing module. The communication module is used for information interaction between the three-axis digital accelerometer and external devices. The communication module sends the corresponding three-axis vibration acceleration digital signals of the X-axis, Y-axis and Z-axis to the external devices according to the control of the signal processing module. The display module is electrically connected to the signal processing module, and the display module is used to display corresponding information according to the control of the signal processing module.

10. The triaxial digital accelerometer according to claim 9, characterized in that, The communication module includes: an Internet-based network interface and / or a near-field point-to-point communication interface; The external device accesses the triaxial digital accelerometer through the Internet-based network interface to obtain the triaxial vibration acceleration digital signals corresponding to the X-axis, Y-axis and Z-axis. The external device establishes a signal connection with the triaxial digital accelerometer through the short-range point-to-point communication interface, and receives the triaxial vibration acceleration digital signals of the corresponding X-axis, Y-axis and Z-axis through the signal connection.

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