A tilt sensor using a novel suspension mechanical structure and a measuring method thereof

Abstract

The application discloses a kind of inclination sensor and its measuring method using new type of suspension mechanical structure.The main structure of the inclination sensor includes: suspension system, measurement system;The suspension system is composed of permanent magnet array, square thermal decomposition graphite suspension piece;Permanent magnet array is composed of four square permanent magnets with magnetization direction staggered arrangement, and the square thermal decomposition graphite suspension piece is stably suspended in the central of permanent magnet array.The measurement system is composed of excitation power supply, measurement unit, modulation circuit, conditioning circuit and signal collector.The measuring method of inclination sensor includes the installation of inclination sensor;Inclination sensor debugging;Actual test of inclination sensor.The inclination sensor proposed in the application has superior static performance, no mechanical wear, can realize high-precision measurement of small inclination, and has the characteristics of high resolution and high sensitivity.The application overcomes the friction problem commonly existing in the existing inclination sensor, and has great advantages in the field of precise measurement of small inclination.

Description

Technical Field

[0001] This invention relates to the field of precision instruments and meters, specifically to an angle sensor employing a novel suspended mechanical structure and its measurement method. Background Technology

[0002] Tilt sensors, as crucial angle measurement units, are widely used in aerospace attitude detection, civil infrastructure health monitoring, and precision instrument manufacturing. With continuous advancements in science and technology, the demand for tilt sensors to measure minute angle changes is constantly increasing. Currently, various high-precision, high-resolution tilt sensors are being developed, making them one of the hot topics in future precision instrument research.

[0003] Common tilt sensors include electrolyte tilt sensors, capacitive tilt sensors, grating tilt sensors, and fiber optic tilt sensors. Electrolyte tilt sensors measure tilt angle by detecting changes in the internal electrolyte level, offering high accuracy and sensitivity. However, they are sensitive to temperature changes and external vibrations, have a slow response time, and are unsuitable for dynamic measurements. Capacitive tilt sensors detect tilt angle by measuring changes in the distance between capacitor plates, offering strong anti-interference capabilities and high resolution. However, they require strict installation and are sensitive to environmental interference such as temperature and vibration. Grating tilt sensors determine the sensor's tilt angle using the spectral characteristics of a grating. They offer high accuracy and strong resistance to electromagnetic interference, but are costly, require complex installation and debugging, need a stable light source, and have poor long-term measurement stability. Fiber optic tilt sensors sense tilt angle by detecting the degree of fiber optic bending, offering advantages such as resistance to electromagnetic interference, corrosion resistance, and high reliability. However, they are costly to manufacture, complex to install and maintain, require strict installation environment conditions, and the fiber optic cable has poor mechanical strength, making it susceptible to damage under severe vibration or bending.

[0004] With the continuous development of precision measurement technology and strong magnetic fields, research on magnetic levitation technology has become increasingly abundant. Materials with magnetic susceptibility less than zero are finding increasingly widespread applications in energy harvesters, high-sensitivity sensors, and other fields due to their characteristics such as passive and stable levitation without external energy input, frictionlessness, and low stiffness. In magnetic levitation technology, materials with magnetic susceptibility less than zero generate an additional magnetic field under the influence of an external magnetic field, with the direction of the additional magnetic field opposite to the external magnetic field. By rationally arranging the external magnetic field and selecting a suitable material with magnetic susceptibility less than zero, combining the two, passive and stable levitation of materials with magnetic susceptibility less than zero can be achieved without external energy input.

[0005] This patent proposes a novel levitation mechanical structure for measuring minute tilt angles by combining electromagnetic induction with magnetic levitation technology. Prior to this, few scholars, both domestically and internationally, had researched tilt angle sensors combining electromagnetic induction and magnetic levitation technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies mentioned above, this invention combines electromagnetic induction with magnetic levitation technology to propose a tilt sensor and its measurement method using a novel levitation mechanical structure. This achieves precise measurement of minute tilt angles, overcoming the friction problem and stringent environmental requirements commonly found in existing tilt sensors. It enables precise and stable measurement of minute tilt angles with low power consumption.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An angle sensor employing a novel levitation mechanical structure comprises a levitation system and a measurement system. The levitation system specifically includes a permanent magnet array and a square pyrolytic graphite suspension sheet. The measurement system specifically includes a measurement unit, an excitation power supply, a modulation circuit, a conditioning circuit, and a signal acquisition unit.

[0009] Furthermore, in the levitation system, the permanent magnet array consists of four square permanent magnets with equal length and width, and a height half the width. The magnetization directions are staggered, with adjacent magnets having opposite magnetization directions, and all magnetization intensities are equal. The four square permanent magnets can naturally attract each other under natural conditions without external force, forming a large square permanent magnet array.

[0010] The area above the square permanent magnet array generates a mountain-shaped magnetic field. The square pyrolytic graphite suspension sheet is excited with magnetic potential energy in the peak-shaped magnetic field and is stably suspended above the permanent magnet array at the point of minimum total potential energy, that is, the center of the permanent magnet array. The total potential energy consists of magnetic potential energy and gravitational potential energy.

[0011] The measuring unit consists of two sets of orthogonally arranged planar spiral coils printed on an FPC circuit board. Each set of planar spiral coils consists of two positive and negative loop inductors with opposite rotation directions. They are located in different branches in the modulation circuit, forming a differential circuit.

[0012] The modulation circuit is used to convert the position signal of the square pyrolytic graphite suspension sheet, which is affected by the change in tilt angle, into an electrical signal in real time.

[0013] The conditioning circuit is used to perform amplitude detection, differential amplification, and low-pass filtering on the electrical signals input from different branches of the modulation circuit.

[0014] Furthermore, the permanent magnet array uses square permanent magnets made of neodymium iron boron material, and the square pyrolytic graphite suspension sheet is made of pyrolytic graphite with a magnetic susceptibility of less than zero.

[0015] Furthermore, the diagonal length of the square pyrolytic graphite suspension sheet is equal to the center distance between the two inductor coils in the same group of planar spiral coils in the measurement unit; the thickness of the square pyrolytic graphite suspension sheet is 0.5 times its suspension height in the center of the permanent magnet array.

[0016] Furthermore, when the relative position of the square pyrolytic graphite suspension sheet and the permanent magnet array changes, each branch in the differential circuit converts the position change of the square pyrolytic graphite suspension sheet into a change in the equivalent impedance of the inductor coil in the measurement unit through the modulation circuit and the conditioning circuit, and then outputs a voltage signal about the tilt angle experienced by the sensor, which is collected by the signal acquisition device; by observing the voltage signal, the magnitude of the tilt angle measured by the sensor is reflected.

[0017] A method for measuring tilt angle using a novel suspended mechanical structure includes the following steps:

[0018] Step S1: Assemble the tilt sensor;

[0019] Step S2: Perform a comprehensive calibration of the tilt sensor using a tilt test bench;

[0020] Step S3: Conduct actual tests on the tilt sensor, analyze the sensor output signal, compare the tested tilt angle with the actual tilt angle, and evaluate the measurement accuracy of the tilt sensor.

[0021] Furthermore, the assembly of the tilt sensor in step S1 is as follows:

[0022] Step S11: Arrange the four square permanent magnets with equal magnetization in an alternating manner to form a permanent magnet array with alternating magnetization directions;

[0023] Step S12: Adhere the measuring unit to the permanent magnet array, with the center of the measuring unit aligned with the center of the permanent magnet array;

[0024] Step S13: Place the square pyrolytic graphite suspension sheet in the center of the permanent magnet array. When it is stably suspended, further adjust the measuring unit to ensure that the centers of its four inductor coils are aligned with the four corners of the square pyrolytic graphite suspension sheet.

[0025] Step S14: Connect the excitation power supply, modulation circuit, conditioning circuit and signal acquisition unit in sequence to complete the assembly of the tilt sensor.

[0026] Furthermore, the specific debugging of the tilt sensor in step S2 is as follows:

[0027] Step S21: Using the tilt test bench, input the tilt angle to the sensor sequentially according to the test step length to conduct sensor performance test.

[0028] Step S22: Record and analyze the performance parameters of the sensor; the performance parameters include input-output curves, range, sensitivity, resolution, and response time; wherein, the tilt angle experienced by the sensor is the input of the sensor, the relative displacement of the square pyrolytic graphite suspension sheet causes a change in the output signal of the conditioning circuit, and the signal collected by the signal acquisition device is the output of the sensor.

[0029] Step S23: Repeat the above test process multiple times to obtain the average curve and complete the debugging; when it comes to actual measurement, use the determined sensor performance parameters as the carrier, and determine the size of the tilt angle by the change in the output signal obtained from the displacement change of the square pyrolytic graphite suspension sheet caused by the tilt angle to be measured.

[0030] Furthermore, the actual testing of the tilt sensor in step S3 is as follows:

[0031] Step S31: Change the tilt angle of the tilt sensor and record the actual tilt angle of the tilt sensor at each change;

[0032] Step S32: Record the sensor output signal during the adjustment of the tilt angle and the determination of the structural parameters.

[0033] Step S33: Compare and analyze the test tilt angle and the actual tilt angle to obtain the measurement accuracy of the tilt sensor and complete the actual test of the tilt sensor.

[0034] Compared with existing technologies, the tilt sensor and its measurement method using a novel suspended mechanical structure described in this invention have the following advantages:

[0035] (1) The tilt sensor proposed in this invention has excellent static performance, no mechanical wear, fast response speed, and is suitable for static angle measurement. It avoids the disadvantages of electrolyte tilt sensors, which are more sensitive to temperature changes and external vibrations, have a slow response speed, and are not suitable for dynamic measurement.

[0036] (2) Compared with capacitive tilt sensors, the present invention has lower equipment installation requirements and is less susceptible to interference from environmental factors such as temperature and vibration. Compared with grating tilt sensors, the present invention has lower cost, simpler installation and debugging, and stronger long-term measurement stability. In addition, compared with fiber optic tilt sensors, the present invention has lower manufacturing cost, simpler installation and maintenance, higher mechanical strength, and is not easily damaged even under severe vibration or bending conditions.

[0037] (3) This invention incorporates magnetic levitation technology, enabling passive and stable levitation of the square pyrolytic graphite suspension sheet without external energy input, thus avoiding friction and reducing sensor power consumption. Combining the high sensitivity of the square pyrolytic graphite suspension sheet with electromagnetic induction measurement, this invention overcomes the friction problem and stringent environmental requirements commonly found in existing tilt sensors, achieving precise and stable measurement of minute tilt angles with low power consumption. Compared to traditional tilt sensors, this invention offers advantages in environmental adaptability and measurement accuracy, meeting the needs of both dynamic and static measurements. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the tilt sensor proposed in this invention;

[0039] Figure 2 This is a view of the suspension system structure in the tilt sensor proposed in this invention;

[0040] Figure 3 This is a top view of the suspension system structure in the tilt sensor proposed in this invention;

[0041] Figure 4 This is a schematic diagram of the potential energy of a square pyrolytic graphite suspension sheet suspended in a permanent magnet array, as proposed in this invention.

[0042] Figure 5 This is a top view of the measuring unit proposed in this invention;

[0043] Figure 6 The graph shows the relationship between the horizontal restoring force exerted by the permanent magnet array on the displacement of the square pyrolytic graphite suspension sheet when the tilt sensor is tilted.

[0044] Figure 7 The graph shows the relationship between the vertical levitation force exerted on the square pyrolytic graphite suspension sheet by the permanent magnet array when the tilt sensor is tilted and the sheet is displaced.

[0045] Figure 8 This is a schematic diagram illustrating the force analysis of a square pyrolytic graphite suspension sheet when the tilt sensor is tilted.

[0046] Figure 9 This is a schematic diagram of the input and output curves of the tilt sensor;

[0047] In the figure, 1-permanent magnet array, 2-square pyrolytic graphite suspension sheet, 3-measurement unit, 4-excitation power supply, 5-modulation circuit, 6-conditioning circuit, 7-signal acquisition unit; Detailed Implementation

[0048] The following is based on examples. Figures 1-9The present invention has been described, but it is not limited to the specific embodiments described herein. In the following detailed description of the invention, certain specific details are described in detail. However, those skilled in the art will fully understand the invention even without these detailed descriptions.

[0049] A tilt sensor employing a novel suspended mechanical structure, the overall structure of which is as follows: Figure 1 As shown, it consists of a suspension system and a measurement system.

[0050] Furthermore, the structure of the suspension system is as follows: Figure 2 , Figure 3 As shown, it specifically includes a permanent magnet array (1) and a square pyrolytic graphite suspension sheet (2).

[0051] Furthermore, the permanent magnet array (1) consists of four square permanent magnets with equal length and width and a height equal to half the width. The magnetization directions are staggered, the magnetization directions of adjacent permanent magnets are opposite, and the magnetization intensity of each permanent magnet is equal. The four square permanent magnets naturally attract each other without the need for external force to form a large square permanent magnet array.

[0052] Furthermore, the square permanent magnets are all made of neodymium iron boron (NdFeB) material. The length, width, and height of the four square permanent magnets are all 10 mm. The square pyrolytic graphite suspension sheet (2) is made of pyrolytic graphite, a material with a magnetic susceptibility of less than zero. The length and width are both 10 mm, and the thickness is 0.4 mm. When the square pyrolytic graphite suspension sheet (2) is stably suspended above the center of the permanent magnet array (1), its suspension height is 0.8 mm.

[0053] Furthermore, in the levitation system structure, the array of permanent magnets (1) with staggered magnetization directions generates a mountain-shaped magnetic field in the middle region. The square pyrolytic graphite levitation sheet (2) is excited with magnetic potential energy in the mountain-shaped magnetic field, such as... Figure 4 As shown, the magnetic potential energy of the square pyrolytic graphite suspension plate (2) has a minimum point. According to the principle of minimum potential energy, the square pyrolytic graphite suspension plate (2) can be passively and stably suspended at the minimum potential energy point, that is, at the center of the permanent magnet array (1). At this time, the square pyrolytic graphite suspension plate (2) is only subjected to the vertical levitation force in the vertical direction and its own weight. The magnitude of the vertical levitation force is equal to the weight of the square pyrolytic graphite suspension plate (2), and the directions are opposite to each other. Thus, the square pyrolytic graphite suspension plate (2) in the suspension system can be passively and stably suspended. This suspension system structure avoids the negative impact of external friction during the measurement process and ensures the free response of the square pyrolytic graphite suspension plate (2), the sensitive element of the tilt sensor, when the sensor is tilted.

[0054] Furthermore, the measurement system specifically includes: a measurement unit (3), an excitation power supply (4), a modulation circuit (5) and a conditioning circuit (6), and a signal acquisition unit (7).

[0055] The top view of the measuring unit (3) is as follows: Figure 5 As shown, the measuring unit (3) consists of two sets of orthogonally arranged planar spiral coils printed on an FPC circuit board. The same set of planar spiral coils consists of two positive and negative loop inductors with opposite rotation directions, forming a differential circuit. The differential principle of the modulation circuit (5) is as follows: For the two inductors in the same set of planar spiral coils installed in different branches of the modulation circuit (5) in the measuring unit (3), their impedance values ​​change with the change of the relative position between the square pyrolytic graphite suspension sheet and the measuring unit, thereby causing the output voltage of each branch of the differential circuit to change to different degrees. The position signal of the square pyrolytic graphite suspension sheet can be obtained by differentially dividing the output voltage. The advantage of the differential circuit is that it can cancel the influence of the bias current on the reference value and effectively reduce the interference of the measurement environment. The modulation circuit (5) is used to convert the position signal of the square pyrolytic graphite suspension sheet (2) caused by the change of tilt angle into an electrical signal in real time.

[0056] The conditioning circuit (6) is used to perform amplitude detection, differential amplification, and low-pass filtering on the electrical signals input from different branches of the modulation circuit (5).

[0057] Furthermore, when the relative position of the square pyrolytic graphite suspension sheet (2) and the permanent magnet array (1) changes, each branch in the differential circuit converts the position change of the square pyrolytic graphite suspension sheet (2) into a change in the equivalent impedance of the inductor coil in the measuring unit (3) through the modulation circuit (5) and the conditioning circuit (6), and then outputs a voltage signal about the tilt angle of the sensor, which is collected by the signal acquisition device (7); by observing the voltage signal, the magnitude of the tilt angle measured by the sensor is reflected.

[0058] Furthermore, the inductor coil in the measurement unit is made of brass with a thickness of 2oz. The outer diameter of a single inductor coil is 1mm, the number of turns is 6, the line width is 0.2mm, and the line spacing is 0.6mm. It is printed on an FPC circuit board with a thickness of 0.2mm. The excitation power supply (4) is a square wave excitation signal with an input frequency of 1.25MHz and an amplitude of 10V.

[0059] Furthermore, the working principle of the tilt sensor is described in detail below:

[0060] In the initial horizontal state, when the square pyrolytic graphite suspension sheet (2) is suspended above the center of the permanent magnet array (1), the square pyrolytic graphite suspension sheet (2) reaches a state of force equilibrium, that is:

[0061] F ⊥ =G (1)

[0062] In equation (1), F ⊥ The vertical levitation force of the square pyrolytic graphite suspension sheet (2) when the permanent magnet array (1) with alternating magnetization directions is vertically upward, and the gravity of the square pyrolytic graphite suspension sheet (2) is vertically downward. These two forces are interaction forces, equal in magnitude and opposite in direction.

[0063] When the tilt angle is θ, the square pyrolytic graphite suspension sheet (2) is stably suspended above the permanent magnet array (1), and its force situation is as follows. Figure 6 , Figure 7 As shown, at this time, the square pyrolytic graphite suspension sheet (2) is additionally subjected to a restoring force F in the horizontal direction by the permanent magnet array (1). / / When the square pyrolytic graphite suspension is in equilibrium, such as... Figure 8 As shown, the horizontal restoring force F acting on it / / Vertical levitation force F ⊥ It is in equilibrium with its own weight G, that is:

[0064] F / / +F ⊥ =G (2)

[0065] In equation (2), F / / The horizontal restoring force of the permanent magnet array (1) with its magnetization directions staggered on the square pyrolytic graphite suspension sheet (2) is parallel to the inclined plane and points towards the center of the permanent magnet array (1). ⊥ G is the vertical levitation force of the permanent magnet array (1) on the square pyrolytic graphite suspension sheet (2), with its direction perpendicular to the inclined plane. G is the weight of the square pyrolytic graphite suspension sheet (2) itself, with its direction vertically downward. The horizontal restoring force F... / / The displacement d of the square pyrolytic graphite suspension sheet (2) increases with the increase of displacement d.

[0066] Figure 6 and Figure 7 The figure shows the vertical levitation force F acting on a square pyrolytic graphite suspension sheet. ⊥ and horizontal restoring force F / / The relationship between the sensor being tilted at an angle θ, causing a displacement d between it and the permanent magnet array. As the displacement d increases, the horizontal restoring force F... / / and vertical levitation force F ⊥ All show an increasing trend. In actual suspension systems, the vertical suspension force F ⊥ The change is much smaller than the horizontal restoring force F. / / The change in the vertical levitation force F ⊥The change is much smaller than the gravity G and vertical levitation force F experienced by the square pyrolytic graphite suspension sheet itself. ⊥ The change in magnitude relative to the horizontal restoring force F / / The change in vertical levitation force F is negligible. ⊥ It can be considered a constant. Within the range of the tilt sensor, the horizontal restoring force F of the square pyrolytic graphite suspension sheet (2) caused by the tilt angle is... ⊥ The change in and the displacement d have a good linear relationship. Therefore, equation (3) can be reasonably simplified to:

[0067] k / / F / / d+F ⊥ =G (3)

[0068] In equation (3), k / / The horizontal restoring force F experienced by the square pyrolytic graphite suspension sheet (2) at different positions. / / The coefficient of variation.

[0069] When the square pyrolytic graphite suspension sheet (2) is stably suspended, according to Figure 8 The diagram shows the force balance of a square pyrolytic graphite suspension sheet when it is stably suspended. The horizontal restoring force F acting on the square pyrolytic graphite suspension sheet (2) in equation (3) can be used to represent this force. / / and vertical levitation force F ⊥ The relationship between gravity and the change in the tilt angle of a square suspension, and its own mass, is as follows:

[0070] k / / mgsinθ·d+mgcosθ=mg (4)

[0071] In equation (4), m is the mass of the square pyrolytic graphite suspension sheet (2), and g is the gravitational constant;

[0072] Therefore, the relationship between the tilt angle θ of the suspension system and the displacement d of the square pyrolytic graphite suspension sheet (2) can be obtained:

[0073]

[0074] For the measurement system, the differential principle in the differential circuit structure of the measurement unit (3) is as follows: For the inductors installed in different branches in the modulation circuit (5), the modulation circuit (5) selects a differential circuit designed based on parallel resonance. The two inductors in the same set of planar spiral coils are distributed on different branches of the differential circuit. When the square pyrolytic graphite suspension plate is displaced by d relative to the measurement unit (3), the impedance value of the inductor changes with the change of the relative position between the square pyrolytic graphite suspension plate and the measurement unit. This causes the voltage of each branch of the modulation circuit (5) to change. The position signal of the square pyrolytic graphite suspension plate (2) is converted into an electrical signal in real time and transmitted to the conditioning circuit (6). The conditioning circuit (6) processes the electrical signal to obtain the output signal, which is then input into the signal acquisition unit (7). This reflects the magnitude of the tilt angle experienced by the sensor. The relationship between the output electrical signal of each branch in the modulation circuit (5) and the displacement d of the square pyrolytic graphite suspension plate (2) is as follows:

[0075] U 1,2 =k(1±d)U in (6)

[0076] In the formula: U 1,2 These represent the output voltages of each branch containing the same set of differential coils, and k is the conversion coefficient.

[0077] After the output electrical signal is processed by the sensor conditioning circuit (6) for amplitude detection, differential amplification, and low-pass filtering, the output signal obtained by the signal acquisition unit (7) is:

[0078] U out =K(U1-U2) (7)

[0079] In the formula: U out The signal output by the conditioning circuit (6) is the signal acquired by the signal acquisition unit (7), and K is the amplification factor of the amplification circuit in the conditioning circuit (7).

[0080] The tilt sensor measurement method using a novel suspended mechanical structure proposed in this invention specifically includes the following steps:

[0081] Step S1: Assemble the tilt sensor;

[0082] Step S2: Perform a comprehensive calibration of the tilt sensor using a tilt test bench;

[0083] Step S3: Conduct actual tests on the tilt sensor, analyze the sensor output signal, compare the tested tilt angle with the actual tilt angle, and evaluate the measurement accuracy of the tilt sensor.

[0084] Furthermore, the assembly of the tilt sensor in step S1 is as follows:

[0085] Step S11: Arrange the four square permanent magnets with equal magnetization in an alternating manner to form a permanent magnet array (1) with alternating magnetization directions;

[0086] Step S12: Adhere the measuring unit (3) to the permanent magnet array (1), with the center of the measuring unit (3) aligned with the center of the permanent magnet array;

[0087] Step S13: Place the square pyrolytic graphite suspension sheet (2) in the center of the permanent magnet array (1). When it is stably suspended, further adjust the measuring unit (3) to ensure that the center of its four inductor coils is aligned with the four corners of the square pyrolytic graphite suspension sheet (2).

[0088] Step S14: Connect the excitation power supply (4), modulation circuit (5), conditioning circuit (6) and signal acquisition unit (7) in sequence to complete the assembly of the tilt sensor.

[0089] Furthermore, the specific debugging of the tilt sensor in step S2 is as follows:

[0090] Step S21: Using the tilt test bench, input the tilt angle to the sensor sequentially according to the test step length to conduct sensor performance test.

[0091] Step S22: Record and analyze the performance parameters of the sensor; the performance parameters include input-output curves, range, sensitivity, resolution, and response time; wherein, the tilt angle experienced by the sensor is the input of the sensor, the relative displacement of the square pyrolytic graphite suspension sheet (2) causes a change in the output signal of the conditioning circuit (6), and the signal collected by the signal acquisition device (7) is the output of the sensor.

[0092] Step S23: Repeat the above test process multiple times to obtain the average curve and complete the debugging; when it comes to actual measurement, use the determined sensor performance parameters as the carrier, and determine the size of the tilt angle by the change in the output signal obtained from the displacement change of the square pyrolytic graphite suspension sheet (2) caused by the tilt angle to be measured.

[0093] Furthermore, the actual testing of the tilt sensor in step S3 is as follows:

[0094] Step S31: Change the tilt angle of the tilt sensor and record the actual tilt angle of the tilt sensor at each change;

[0095] Step S32: Record the sensor output signal during the adjustment of the tilt angle and the determination of the structural parameters.

[0096] Step S33: Compare and analyze the test tilt angle and the actual tilt angle to obtain the measurement accuracy of the tilt sensor and complete the actual test of the tilt sensor.

Claims

1. A tilt sensor employing a novel suspended mechanical structure, characterized in that, It consists of a suspension system and a measurement system; The suspension system includes a permanent magnet array (1) and a square pyrolytic graphite suspension sheet (2); the measurement system includes a measurement unit (3), an excitation power supply (4), a modulation circuit (5), a conditioning circuit (6), and a signal acquisition unit (7); The permanent magnet array (1) consists of four square permanent magnets with the same length and width and a height that is half the width. The magnetization directions are staggered, that is, the magnetization directions of adjacent permanent magnets are opposite, and the magnetization intensity of the permanent magnets is equal. The four square permanent magnets naturally attract each other without the need for external force to form a large square permanent magnet array. The area above the square permanent magnet array generates a mountain-shaped magnetic field. The square pyrolytic graphite suspension sheet (2) is excited with magnetic potential energy in the peak-shaped magnetic field and is stably suspended above the permanent magnet array at the point of minimum total potential energy, that is, the center of the permanent magnet array. The total potential energy consists of magnetic potential energy and gravitational potential energy; The measuring unit (3) consists of two sets of orthogonally arranged planar spiral coils printed on an FPC circuit board; each set of planar spiral coils consists of two positive and negative ring structure inductors with opposite rotation directions and located in different branches in the modulation circuit (5) to form a differential circuit. The modulation circuit (5) is used to convert the position signal of the square pyrolytic graphite suspension sheet (2) caused by the change in tilt angle into an electrical signal in real time. The conditioning circuit (6) is used to perform amplitude detection, differential amplification, and low-pass filtering on the electrical signals input from different branches of the modulation circuit (5).

2. The tilt sensor employing a novel suspended mechanical structure according to claim 1, characterized in that, The permanent magnet array (1) uses square permanent magnets made of neodymium iron boron material, and the square pyrolytic graphite suspension sheet (2) is made of pyrolytic graphite with a magnetic susceptibility of less than zero.

3. The tilt sensor employing a novel suspended mechanical structure according to claim 1, characterized in that, The diagonal length of the square pyrolytic graphite suspension sheet (2) is equal to the center distance of the inductor coils in the same group of planar spiral coils in the measuring unit (3); the thickness of the square pyrolytic graphite suspension sheet (2) is 0.5 times its suspension height in the center of the permanent magnet array (1).

4. The tilt sensor employing a novel suspended mechanical structure according to claim 1, characterized in that, When the relative position of the square pyrolytic graphite suspension sheet (2) and the permanent magnet array (1) changes, each branch in the differential circuit converts the position change of the square pyrolytic graphite suspension sheet (2) into the change of the equivalent impedance of the inductor coil in the measuring unit (3) through the modulation circuit (5) and the conditioning circuit (6), and then outputs a voltage signal about the tilt angle of the sensor, which is collected by the signal acquisition device (7); by observing the voltage signal, the magnitude of the tilt angle measured by the sensor is reflected.

5. A method for measuring an angle sensor employing a novel suspension mechanical structure, wherein the angle sensor employing a novel suspension mechanical structure according to any one of claims 1 to 4 is characterized in that, The method includes the following steps: Step S1: Assemble the tilt sensor; Step S2: Perform a comprehensive calibration of the tilt sensor using a tilt test bench; Step S3: Conduct actual tests on the tilt sensor, analyze the sensor output signal, compare the tested tilt angle with the actual tilt angle, and evaluate the measurement accuracy of the tilt sensor.

6. The method for measuring an angle sensor using a novel suspended mechanical structure according to claim 5, characterized in that, The assembly of the tilt sensor in step S1 is as follows: Step S11: Arrange the four square permanent magnets with equal magnetization in an alternating manner to form a permanent magnet array (1) with alternating magnetization directions; Step S12: Adhere the measuring unit (3) to the permanent magnet array (1), with the center of the measuring unit (3) aligned with the center of the permanent magnet array; Step S13: Place the square pyrolytic graphite suspension sheet (2) in the center of the permanent magnet array (1). When it is stably suspended, further adjust the measuring unit (3) to ensure that the centers of its four inductor coils are aligned with the four corners of the square pyrolytic graphite suspension sheet (2). Step S14: Connect the excitation power supply (4), modulation circuit (5), conditioning circuit (6) and signal acquisition unit (7) in sequence to complete the assembly of the tilt sensor.

7. The method for measuring tilt angle using a novel suspended mechanical structure according to claim 5, characterized in that, The specific steps for adjusting the tilt sensor in step S2 are as follows: Step S21: Using the tilt test bench, input the tilt angle to the sensor sequentially according to the test step length to conduct sensor performance test. Step S22: Record and analyze the performance parameters of the sensor; the performance parameters include input-output curves, range, sensitivity, resolution, and response time; wherein, the tilt angle experienced by the sensor is the input of the sensor, the relative displacement of the square pyrolytic graphite suspension sheet (2) causes a change in the output signal of the conditioning circuit (6), and the signal collected by the signal acquisition device (7) is the output of the sensor. Step S23: Repeat the above test process multiple times to obtain the average curve and complete the debugging; when it comes to actual measurement, use the determined sensor performance parameters as the carrier, and determine the size of the tilt angle by the change in the output signal obtained from the displacement change of the square pyrolytic graphite suspension sheet (2) caused by the tilt angle to be measured.

8. The method for measuring an angle sensor using a novel suspended mechanical structure according to claim 5, characterized in that, The actual test of the tilt sensor in step S3 is as follows: Step S31: Change the tilt angle of the tilt sensor and record the actual tilt angle of the tilt sensor at each change; Step S32: Record the sensor output signals of the structural parameters determined during the tilt angle adjustment process; Step S33: Compare and analyze the test tilt angle and the actual tilt angle to obtain the measurement accuracy of the tilt sensor and complete the actual test of the tilt sensor.

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