Active and passive suspension tilt sensor and test method thereof

Abstract

The present invention discloses an active and passive suspension type inclination sensor, comprising a support frame, a magnetic pole array, a suspension ring, a non-magnetic metal ring, a magnetic permeable core, an excitation coil, a photoelectric displacement sensor, a controller, and a power amplifier; the non-magnetic metal ring is nested inside the suspension ring; the magnetic pole array is located below the suspension ring to realize the suspension of the suspension ring and the non-magnetic metal ring; the magnetic permeable core passes through the non-magnetic metal ring, the excitation coil adopts a differential structure, and the photoelectric displacement sensor is arranged on both sides of the non-magnetic metal ring to measure the position signal of the non-magnetic metal ring; the non-magnetic metal ring is induced to generate a corresponding electromagnetic force by the control current in the excitation coil, and the resultant force on the non-magnetic metal ring is the difference between the two forces, and the position changes until the non-magnetic metal ring stabilizes at a preset position. The present invention realizes the high-precision measurement function of small inclination angles, and the anti-magnetic suspension overcomes the friction problem commonly existing in existing high-precision inclination sensors, and realizes the measurement of large angles.

Description

Technical Field

[0001] The invention discloses a hybrid anti-magnetic suspension inclination sensor with a large measuring range, which combines an active suspension control mode based on the Thomson jump ring principle with a passive suspension mode based on the anti-magnetic suspension principle, and belongs to the field of precision instruments. Background Art

[0002] As one of the most important angle measurement units, the inclinometer is widely used in military and civilian fields, such as robot posture monitoring, vehicle control, ship transportation, aerial measurement, platform testing, agricultural machinery and construction machinery. With the increasing demand for the simplification and precision of measurement technology, especially for a series of aerial vehicles such as floating photoelectric detection platforms used to achieve space target positioning, capture and tracking, the measurement accuracy of their flight attitude directly affects the accuracy of target capture. Various high-precision inclinometers have been gradually developed, which has attracted great attention in related fields.

[0003] The inclination sensor is generally composed of a stator, a sensitive element, a conversion element and a conversion circuit. The inclination angle is measured by measuring the relative movement of the sensitive element relative to the stator in the tilt state and converting it into an electrical signal. At present, the high-precision inclination measurement methods are mainly fiber grating, capacitive, and resonant. Among them, the fiber grating inclination sensor mainly measures the change of the corresponding wavelength. The capacitive inclination sensor is mostly liquid sensitive elements. The inclination is measured by the difference in capacitance under different tilt states. The resonant inclination sensor mainly measures the change of the system resonance frequency caused by different deformations. Among them, the fiber grating inclination sensor has the best measurement accuracy, followed by the capacitive and resonant types.

[0004] However, most of the current high-precision inclination sensors cannot get rid of the negative impact of the relative friction between the sensitive element and the stator. The added damping severely limits the change in the relative motion of the sensitive element, restricts the size of the minimum measurable angle, and structurally limits the development of high-precision inclination measurement. For the measurement of tiny angles, it cannot meet the detection requirements of ultra-high precision instruments.

[0005] Diamagnetic levitation is a technology that uses the diamagnetism of diamagnetic materials to make them suspend stably in a magnetic field. It was first discovered in the 18th century, but because the diamagnetic force itself is very weak, researchers did not conduct in-depth research on diamagnetic levitation at that time. It was not until the past 30 years, with the development of micro-manufacturing and strong magnetic field technology, that research and applications related to diamagnetic levitation began to rise. Diamagnetic levitation is not limited by Earnshaws' theorem, and can achieve room temperature, passive, frictionless, static stable suspension, and has ultra-high sensitivity to changes in the gravity of the suspended object. Its low stiffness and temperature insensitivity make it have great application prospects in high-precision and ultra-high precision instrument angle measurement. However, due to the limitation of the diamagnetic force level, the improvement of its measurement range is severely restricted. Therefore, the present invention designs and proposes a new type of active and passive suspension inclination sensor, and discloses its specific measurement method, explores the high sensitivity advantages brought by frictionlessness and low stiffness, and improves the measurement range performance of the sensor, so that it is oriented to the measurement of ultra-high precision instruments.

[0006] Prior to the present invention, in terms of the measurement of small angles, most of the domestic research focused on the research of fiber grating, capacitive, resonant and other inclination sensors, and no inclination measurement technology similar to this patent that combines the anti-magnetic suspension principle with the active suspension control method based on the Thomson jump ring principle has been found. Summary of the invention

[0007] Purpose of the invention: The present invention aims to improve the measurement accuracy and measurement range of small angles to meet the needs of posture monitoring of high-precision and ultra-high-precision instruments, and proposes an active and passive suspension inclination sensor that combines an active suspension control method based on the Thomson jump ring principle with a passive suspension method based on the anti-magnetic suspension principle.

[0008] Technical solution:

[0009] An active and passive suspension inclination sensor comprises a support frame, a magnetic pole array, a suspension ring, a non-magnetic metal ring, a magnetic permeable core, an excitation coil, a photoelectric displacement sensor, a controller, and a power amplifier; the magnetic pole array is a tile-shaped array composed of N sector-shaped magnetic poles of the same shape, N is a natural number greater than 2, the magnetization direction of each sector-shaped magnetic pole is radiation magnetization and the magnetization intensity is equal, the sector-shaped magnetic poles are arranged alternately in the north and south poles, that is, the magnetization directions of adjacent sector-shaped magnetic poles are arranged in two directions, namely, inward radiation and outward radiation, and they are naturally attracted together without external force; the suspension ring and the non-magnetic metal ring are assembled together by interference fit, the non-magnetic metal ring is nested inside the suspension ring, and the suspension ring is made of anti-magnetic material; the magnetic pole array is located in the suspension ring. Below the floating ring, an upward force is generated on the suspension ring to achieve suspension of the suspension ring and the non-magnetic metal ring; the magnetic core passes through the non-magnetic metal ring, and the excitation coil adopts a differential structure, that is, two sets of coils are used, which are symmetrically wound on the two ends of the magnetic core. After the excitation coils are energized, they both generate repulsive force on the suspension ring in the middle, and the magnetic core is fixed by a support frame; photoelectric displacement sensors are arranged on both sides of the non-magnetic metal ring to measure the position signal of the non-magnetic metal ring; in the magnetic field environment provided by the magnetic pole array, the total potential energy of the suspension ring and the non-magnetic metal ring is composed of magnetic potential energy and gravitational potential energy. The suspension ring and the non-magnetic metal ring are stably suspended at the minimum point of the total potential energy. Based on the gradient relationship between force and potential energy, the combined external force at the minimum point of the total potential energy is is 0, that is, the anti-magnetic force is equal to the position of the gravity of the suspension ring and the non-magnetic metal ring. The suspension of the suspension ring and the non-magnetic metal ring avoids the negative impact of friction, ensuring the free response of the inclination sensor sensitive element, that is, the suspension ring (combined with the non-magnetic metal ring); the photoelectric displacement sensor converts the collected position signal of the non-magnetic metal ring into an electrical signal in real time, and transmits it to the controller. The controller calculates the difference between the electrical signal measured by the photoelectric displacement sensor and the preset position electrical signal to generate a control quantity that makes the difference zero and inputs it into the power amplifier. The preset position electrical signal is a current signal set when the suspension ring reaches the preset position when the tilt angle is zero, and the corresponding control current is generated through the amplification of the power amplifier. The control current and the bias signal set by the circuit are processed by the addition and subtraction circuits to generate two signals with a difference of twice the control current. Two output currents are generated under the amplification of the power amplifier. The two output currents are respectively input into the upper and lower groups of excitation coils. The non-magnetic metal ring is induced by the control current in the excitation coil to induce the corresponding electromagnetic force. The two groups of excitation coils exert opposite forces on the non-magnetic metal ring. The resultant force on the non-magnetic metal ring is the difference between the two forces, which changes the position of the non-magnetic metal ring until the non-magnetic metal ring stabilizes at the preset position, that is, the difference between the electrical signal measured by the photoelectric displacement sensor and the electrical signal at the preset position is zero. The active and passive suspension inclination sensor is integrally sealed.

[0010] Furthermore, the magnetic pole array may be arranged in a "Halbach" arrangement, that is, the magnetization direction of the sector-shaped magnetic poles is radiating outwards, and is arranged in a counterclockwise circumferential direction, radiating inwards, and clockwise circumferential direction in sequence.

[0011] Furthermore, the preset position is a position where the suspension ring is equidistant from the two photoelectric displacement sensors.

[0012] Furthermore, the number of N is 5.

[0013] Furthermore, the inner diameter of the suspension ring is slightly smaller than the outer diameter of the non-magnetic metal ring, and the difference between the two is kept below 0.1 mm, so that an interference fit can be achieved by using a shrink sleeve.

[0014] Furthermore, the length of the suspension ring is the same as that of the non-magnetic metal ring, and the ratio of the length of the magnetic pole array to the length of the suspension ring or the length of the non-magnetic metal ring is greater than or equal to 3.

[0015] Furthermore, the number of non-magnetic metal rings is 2, which are of the same size and shape and are aligned with the two ends of the suspension ring, respectively, and the ratio of the length of the suspension ring to the length of a single non-magnetic metal ring is greater than 2. The use of double-ring non-magnetic metal rings can reduce the overall weight of the suspension ring and the non-magnetic metal rings and reduce the volume of the magnetic pole array.

[0016] Furthermore, in order to ensure the suspension of the cylindrical suspension rod and increase the axial motion range of the cylindrical suspension rod, the ratio of the wall thickness of the suspension ring to the wall thickness of the non-magnetic metal ring is greater than 1.

[0017] Furthermore, the inclination measurement model of the active and passive suspension inclination sensor, i.e., the force balance equation, is:

[0018]

[0019] F 感电 =Gsinθ=mgsinθ (3)

[0020]

[0021] Wherein, formula (1) is the expression of the induced electromagnetic force, K is the electromagnetic force coefficient, which can be regarded as a constant when the moving position of the non-magnetic metal ring during the angle change is not large relative to the preset position, and its magnitude is determined by the frequency of the excitation current in the excitation coil, the material properties of the non-magnetic metal ring, and the mutual inductance coefficient between the excitation coil and the non-magnetic metal ring; I0+I z , I0-I z are the total current amplitudes flowing through the excitation coils at both ends of the magnetic core shaft, where I0 is the bias current amplitude of the excitation coil, I z is the control current amplitude; z0 is the preset initial position, z kis the movement of the non-magnetic metal ring relative to the preset initial position; m is the sum of the masses of the suspension ring and the non-magnetic metal ring, and θ is the tilt angle. During the sensor debugging phase, the sensor input-output curve is tested experimentally to measure performance parameters such as range, sensitivity, and resolution. The tilt angle θ is the input of the sensor and the control current amplitude I z is the output of the sensor; after debugging, when it is used in actual application, the determined performance parameters are used as the carrier, and the corresponding angle value is output according to the change of current caused by the angle to be measured; when the measured angle is deflected clockwise, the angle becomes smaller, and the suspension ring and the non-magnetic metal ring move in the opposite direction of the z-axis. At this time, the total current amplitude flowing through the excitation coils at both ends of the magnetic core shaft is I0-I z 、I0+I z , to achieve the measurement of tilt angle, the advantages of the differential structure of the active and passive suspension inclination sensor can achieve the measurement of full range angles.

[0022] A method for testing an active and passive suspension inclination sensor includes the following three steps:

[0023] Step 1, install the active and passive suspended inclinometer. First, pass the magnetic core shaft through the non-magnetic metal ring that is interference fit with the suspension ring, wind the excitation coil of the differential structure around the two ends of the magnetic core shaft, fix the magnetic core shaft, adjust the distance between the magnetic pole array and the suspension ring, and after the suspension ring is stably suspended and has no contact with the magnetic core shaft, fix the magnetic pole array, adjust the position of the photoelectric displacement sensor, so that the laser it emits is aligned with the non-magnetic metal ring, ensure that the distance between the photoelectric displacement sensor and the non-magnetic metal ring is in the linear working area of ​​the photoelectric displacement sensor, and complete the installation of the active and passive suspended inclinometer.

[0024] Step 2, debug the active and passive suspended inclination sensor, change the size of the inclination angle by adjusting the depth micrometer, measure and record the size of the output current of the power amplifier at this time, draw a curve of the output current changing with the inclination angle, repeat the experiment many times, obtain the average curve, reveal the measurement range, linear area, linearity, sensitivity of the active and passive suspended inclination sensor, test the performance parameters such as resolution, response time, repetition rate, and complete the debugging of the active and passive suspended inclination sensor;

[0025] Step 3: Test the active and passive suspended inclinometers. Change and record the actual tilt angle by adjusting the depth micrometer. At the same time, record the measured angle of the active and passive suspended inclinometers based on the performance parameters determined during the debugging process. Compare and analyze the actual tilt angle with the test angle to obtain the measurement accuracy and complete the actual test of the active and passive suspended inclinometers. Specifically: First, the depth micrometer is used to change the rising height of the plate. When the depth micrometer is not moved, the rising height of the plate remains unchanged. At this time, the tilt angle of the plate remains unchanged. Through θ 实际=arctan(h / l), where h is the rising height of the plate; l is the horizontal distance between the depth micrometer and the hinge, which is a constant value, from which the actual tilt angle of the plate can be calculated. Next, place the sensor on the plate. The sensor outputs the tilt angle measured by the sensor according to the curve and other performance parameters obtained during the debugging process in step 2, and obtains it according to formula (4); at this time, compare and analyze the actual angle of the plate and the tilt angle measured by the sensor to obtain the sensor accuracy. Finally, by continuously adjusting the depth micrometer and changing the rising height h of the plate, the actual tilt angle of the plate at any time can be obtained. At the same time, the tilt angle obtained by the sensor at any time can also be obtained, and by comparison and analysis, the average value of the sensor accuracy can be obtained to complete the actual test.

[0026] Beneficial effects: (1) The high-precision measurement function of small inclination angles is realized. The anti-magnetic suspension overcomes the friction problem commonly existing in existing high-precision inclination sensors, realizes the free response of the sensor's sensitive elements, and the low stiffness makes the sensor extremely sensitive, which has a natural advantage in the measurement of small angles. (2) The measurement of a wide range of angles can be realized. The active and passive suspension inclination sensor breaks through the bottleneck of the measurement range of the anti-magnetic suspension inclination sensor due to the limitation of the anti-magnetic force level, which is limited by the insufficient compensation margin of the gravity component. The proposed active and passive suspension inclination sensor no longer relies on the anti-magnetic force to compensate the gravity component of the sensitive element. The controllable electromagnetic force is generated by the Thomson jump ring system to compensate the gravity component of the sensitive element, ensuring the suspension of the sensitive element at a large angle and realizing the measurement of a large angle. (3) It has the potential for miniaturization. The ratio of the anti-magnetic suspension force of the suspension ring to the gravity of the suspension ring is positively correlated with the surface area of ​​the cylindrical rod. Therefore, under the scale effect, the ratio of the anti-magnetic suspension force to the gravity of the suspension ring increases with the decrease of the scale, which can realize the miniaturization of the suspension ring and has broad prospects in the development of micro-nano. (4) Anti-magnetic suspension is not limited by Earnshaws theorem and can achieve room temperature, passive, frictionless, static stable suspension without any energy input, greatly simplifying the structure and cost of the sensor system. (5) Easy to process. The key components of the active and passive suspension inclination sensor, namely the components of the mechanical system, have regular shapes, which are easy to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the overall structure of the active and passive suspension tilt sensor;

[0028] Figure 2 A three-dimensional schematic diagram of the main mechanical structure of the active and passive suspension inclination sensor;

[0029] Figure 3 It is a schematic diagram of the mechanical system suspension of the active and passive suspension tilt sensor;

[0030] Figure 4 A schematic diagram of the three-dimensional magnetic field of the radiation magnetized magnetic pole array in the "Opposite" arrangement;

[0031] Figure 5 It is a schematic diagram of the three-dimensional total potential energy of the suspension ring and the non-magnetic metal ring;

[0032] Figure 6 (a) is a cross-sectional view of a single suspension ring and a single non-magnetic metal ring; Figure 6 (b) is a cross-sectional view of a single suspension ring and two non-magnetic metal rings;

[0033] Figure 7 It is the schematic diagram of the power amplifier addition and subtraction processing circuit;

[0034] Figure 8 Schematic diagram of the magnetization direction of the radiation magnetized magnetic pole array in the "Opposite" arrangement;

[0035] Fig. 9 It is a schematic diagram of the force conditions of the suspension ring and the non-magnetic metal ring and the measurement principle;

[0036] Fig.10 It is a schematic diagram of input and output curves of active and passive suspension tilt sensors; DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings:

[0038] Figure 1 The schematic diagram of the overall structure of the active and passive suspension inclination sensor. The active and passive suspension is composed of the axial active suspension based on the Thomson jump ring principle and the radial passive suspension based on the anti-magnetic suspension principle. The active suspension generates an electromagnetic force by the excitation coil to act on the non-magnetic metal ring in real time, offsetting the axial gravity component of the inclination sensitive element composed of the suspension ring and the non-magnetic metal ring at different tilt angles, and realizing the axial stable suspension of the inclination sensitive element; the passive suspension generates an anti-magnetic force on the suspension ring through the magnetic pole array, offsetting the radial gravity component of the inclination sensitive element composed of the suspension ring and the non-magnetic metal ring at different tilt angles, and realizing the radial stable suspension of the inclination sensitive element. The main mechanical structure of the active and passive suspension inclination sensor is as follows: Figure 2 shown.

[0039] The active and passive suspension inclination sensor of the present invention comprises a support frame 1, a magnetic pole array 2, a suspension ring 3, a non-magnetic metal ring 4, a magnetic permeable core 5, an excitation coil 6, a photoelectric displacement sensor 7, a controller 8, and a power amplifier 9; h is the rising height of the plate, and l is the horizontal distance between the depth micrometer and the hinge.

[0040] In the mechanical structure, the radiation magnetization magnetic pole array 2 of the "Opposite" arrangement form of the magnetic pole array (2) is composed of 5 sector-shaped radiation magnetization magnetic poles arranged alternately in the north and south poles, each magnetic pole is made of neodymium iron boron (NdFeB) material, the magnetization direction of the sector-shaped magnetic poles is radiation magnetization, and the magnetization intensity is equal. The arrangement form of the 5 sector-shaped magnetic poles (5) is the "Opposite" form, such as Figure 3 As shown, the fan-shaped magnetic poles are arranged alternately in north and south poles, and can be naturally attracted together without external force. The inner diameter is 10.2mm, the outer diameter is 50.2mm, and the length is 60mm; the suspension ring (3) is made of anti-magnetic material pyrolytic graphite, with an inner diameter of 8mm, an outer diameter of 10mm, and a length of 8mm; the non-magnetic metal ring 4 is made of non-magnetic metal aluminum, with an inner diameter of 7mm, an outer diameter of 8mm, and a length of 8mm.

[0041] like Figure 4 As shown, the magnetic pole array 2 can spontaneously generate a hump-shaped magnetic field in the three directions of x, y, and z, and the suspension ring 3 excites magnetic potential energy in the hump-shaped magnetic field, such as Figure 5 As shown, the total potential energy of the suspension ring 3 and the non-magnetic metal ring 4 consists of two parts: magnetic potential energy and gravitational potential energy. The suspension ring 3 and the non-magnetic metal ring 4 are stably suspended at the minimum point of the total potential energy. Based on the gradient relationship between force and potential energy, the combined external force at the minimum point of the total potential energy is 0, that is, the anti-magnetic force is equal to the gravity of the suspension ring 3 and the non-magnetic metal ring 4. The suspension of the suspension ring 3 and the non-magnetic metal ring 4 avoids the negative impact of friction and ensures the free response of the tilt sensor sensitive element, that is, the combination of the suspension ring 3 and the non-magnetic metal ring 4. The inner diameter of the suspension ring 3 is slightly smaller than the outer diameter of the non-magnetic metal ring 4, and the difference between the two is kept below 0.1mm. The non-magnetic metal ring 4 is nested in the suspension ring 3 to ensure the interference fit between the two. The specific implementation method can be implemented in the form of a shrink sleeve to achieve interference fit. To ensure the suspension of the cylindrical suspension rod 3, the axial motion range of the cylindrical suspension rod 3 is increased at the same time. The ratio of the wall thickness of the suspension ring 3 to the wall thickness of the non-magnetic metal ring 4 should be greater than 1, the length of the suspension ring 3 and the non-magnetic metal ring 4 are the same, and the ratio of the length of the magnetic pole array 2 to the length of the suspension ring 3 or the length of the non-magnetic metal ring 4 should be greater than or equal to 3. Figure 6 The number of non-magnetic metal rings 4 can also be 2, which are of the same size and shape and are aligned with the two ends of the suspension ring 3 respectively, and the ratio of the length of the suspension ring 3 to the length of a single non-magnetic metal ring 4 is greater than 2, as shown in FIG. Figure 6 (b) As shown in FIG. 4 , the use of the double-ring non-magnetic metal ring 4 can reduce the overall weight of the suspension ring 3 and the non-magnetic metal ring 4 and reduce the volume of the magnetic pole array 2 .

[0042] The magnetic pole array 2 is located below the suspension ring 3, generating an upward force on the suspension ring 3, thereby achieving suspension of the suspension ring 3 and the non-magnetic metal ring 4; the magnetic core 5 passes through the non-magnetic metal ring 4, and the excitation coil 6 adopts a differential structure, that is, two sets of coils are respectively wound around the two ends of the magnetic core, and are symmetrically distributed. After the excitation coils are energized, they both generate a repulsive force on the middle suspension ring 3, and the magnetic core 5 is fixed by the support frame 1; the photoelectric displacement sensor 7 is arranged on both sides of the non-magnetic metal ring 4 to measure the position signal of the non-magnetic metal ring 4; the photoelectric displacement sensor 7 converts the collected position signal of the non-magnetic metal ring 4 into an electrical signal in real time and transmits it to the controller 8 , the controller 8 calculates the difference between the electric signal measured by the photoelectric displacement sensor 7 and the electric signal of the preset position, generates a control quantity that makes the difference zero, and inputs it into the power amplifier 9. The preset position electric signal is the current signal when the suspension ring 3 reaches the preset position when the tilt angle is zero. The preset position is the position where the suspension ring 3 is equidistant from the two photoelectric displacement sensors; the corresponding control current is generated through the amplification effect of the power amplifier 9, and the control current in the power amplifier 9 and the bias signal set by the circuit are processed by the addition and subtraction circuits respectively to generate two signals with a difference of twice the control current, and two output currents are generated under the amplification effect of the power amplifier 9.

[0043] like Figure 7 As shown, the differential principle of the excitation coil 6 of the differential structure is that for the same control quantity output by the controller, two output signals with a difference of twice the control quantity are generated by the addition circuit and the subtraction circuit respectively. The two output currents are respectively input into the upper and lower groups of excitation coils 6. The non-magnetic metal ring 4 is induced to generate a corresponding electromagnetic force by the control current in the excitation coil 6. The forces generated by the two groups of excitation coils 6 on the non-magnetic metal ring 4 are in opposite directions. The resultant force on the non-magnetic metal ring 4 is the difference between the two forces, and the size of the difference is related to the control quantity. The influence of the reference value brought by the bias current can be offset by the differential structure.

[0044] The photoelectric displacement sensor 7 converts the position signal of the non-magnetic metal ring 4 into an electrical signal in real time, and transmits it to the controller 8. The controller 8 generates a control quantity that makes the difference zero based on the difference between the electrical signal measured by the photoelectric displacement sensor 7 and the preset electrical signal, and inputs it into the power amplifier 9. The corresponding control current is generated through the amplification effect of the power amplifier 9 and input into the excitation coil 6. According to the Thomson jump ring principle, the non-magnetic metal ring 4 is induced to induce a corresponding electromagnetic force by the control current in the excitation coil 6, so that the position of the non-magnetic metal ring 4 changes until the non-magnetic metal ring 4 stabilizes at the preset position, that is, the difference between the electrical signal measured by the photoelectric displacement sensor 7 and the preset electrical signal is zero.

[0045] The magnetic core shaft 5 is made of a material with high magnetic permeability, such as silicon steel sheet, electrical pure iron, etc., with a diameter of 6 mm. The length is selected with the maximum electromagnetic force coefficient as the goal, and the installation of the excitation coil 6 is also considered for selection. In this example, the length of the magnetic core is 300 mm; the number of turns of the excitation coil can also be selected using the controlled variable method and retrograde selection, that is, when other conditions remain unchanged, the maximum electromagnetic force is selected as the goal. In this example, 1000 turns are selected.

[0046] The selection of the photoelectric displacement sensor 7 depends on the application background. For fields with high requirements for the resolution of the inclination sensor, a high-resolution photoelectric displacement sensor is selected, but it must be ensured that it works in the linear working area of ​​the photoelectric displacement sensor; the design of the controller depends on the application background. For fields with high requirements for the measurement range of the inclination sensor, a μ-synthesis controller can be developed, and for fields with low requirements for the measurement range, an adaptive PID controller can be developed.

[0047] The inclination measurement model of the active and passive suspension inclination sensor, i.e. the force balance equation, is:

[0048]

[0049] F 感电 =Gsinθ=mgsinθ (3)

[0050]

[0051] Wherein formula (1) is the expression of the induced electromagnetic force, K is the electromagnetic force coefficient, which can be regarded as a constant when the moving position of the non-magnetic metal ring during the angle change is not large relative to the preset position, and its magnitude is determined by the frequency of the excitation current in the excitation coil 6, the material properties of the non-magnetic metal ring 4, and the mutual inductance coefficient between the excitation coil 6 and the non-magnetic metal ring 4; I0+I z , I0-I z are the total current amplitudes flowing through the excitation coil 6 at both ends of the magnetic core shaft 5, where I0 is the bias current amplitude of the excitation coil, I z is the control current amplitude; z0 is the preset initial position, z k is the movement of the non-magnetic metal ring 4 relative to the preset initial position; m is the sum of the masses of the suspension ring 3 and the non-magnetic metal ring 4, and θ is the tilt angle. During the sensor debugging phase, the sensor input-output curve is tested experimentally to measure performance parameters such as range, sensitivity, and resolution. The tilt angle θ is the input of the sensor, and the control current amplitude I zis the output of the sensor; after debugging, when it is used in actual application, the determined performance parameters are used as the carrier, and the corresponding angle value is output according to the change of the current caused by the angle to be measured; when the measured angle is deflected clockwise, the angle becomes smaller, and the suspension ring 3 and the non-magnetic metal ring 4 move in the opposite direction of the z-axis. At this time, the total current amplitude flowing through the excitation coil 6 at both ends of the magnetic core shaft 5 is I0-I z 、I0+I z , to achieve the measurement of tilt angle, the advantages of the differential structure of the active and passive suspension inclination sensor can achieve the measurement of full range angles.

[0052] In the mechanical system, the magnetic pole arrangement of the radiation magnetized magnetic pole array 2 is not limited to the "Opposite" arrangement, but can also be the "Halbach" arrangement, such as Figure 8 As shown, the magnetization direction of the sector poles is radiating outwards, and they are arranged in a counterclockwise circumferential direction, radiating inwards, and clockwise circumferential direction.

[0053] The active and passive suspension inclinometer tilt sensor's inclination measurement principle: Taking the measured angle deflected counterclockwise along the horizontal line as an example, the force conditions of the suspension ring 3 and the non-magnetic metal ring 4 in the active and passive suspension inclinometer in the tilt state are as follows: Fig. 9 As shown, the change of the gravity component makes both of them have a tendency to move along the z direction. Through the real-time detection of the position signal by the photoelectric displacement sensor 7, when the position of the non-magnetic metal ring 4 is deflected, the controller 8 generates a corresponding control current which is amplified by the power amplifier 9. The control current in the power amplifier 9 and the bias signal set by the circuit are processed by the addition and subtraction circuits respectively to generate two signals with a difference of twice the control current. Under the amplification effect of the power amplifier 9, two output currents are generated. The two output currents are respectively input into the upper and lower groups of excitation coils 6. The non-magnetic metal ring 4 is induced to have a corresponding electromagnetic force by the control current in the excitation coil 6. The induced electromagnetic force acts on the non-magnetic metal ring 4 until it reaches the preset position. The preset position is the position of the non-magnetic metal ring 4 in the horizontal state. At this time, the anti-magnetic force in the z direction is 0.

[0054] The active and passive suspension inclination sensor inclination test method includes the following three steps:

[0055] Step 1, installation of active and passive suspended inclinometer. First, pass the magnetic core shaft 5 through the non-magnetic metal ring 4 that is interference fit with the suspension ring 3, wind the excitation coil 6 of the differential structure around the two ends of the magnetic core shaft 5, fix the magnetic core shaft 5, and adjust the distance between the radiation magnetized magnetic pole array 2 in the "Opposite" arrangement and the suspension ring. After the suspension ring 3 is stably suspended and has no contact with the magnetic core shaft 5, fix the radiation magnetized magnetic pole array 2 in the "Opposite" arrangement, adjust the position of the photoelectric displacement sensor 7, so that the laser it emits is aimed at the non-magnetic metal ring 4, ensure that the distance between the photoelectric displacement sensor 7 and the non-magnetic metal ring 4 is in the linear working area of ​​the photoelectric displacement sensor 7, and complete the installation of the active and passive suspended inclinometer;

[0056] Step 2, debugging of active and passive suspension inclination sensors. By adjusting the depth micrometer 10 to change the inclination angle, measure and record the output current of the power amplifier at this time, draw a curve of the output current changing with the inclination angle, repeat the experiment many times, and obtain the average curve, such as Fig.10 As shown, the measurement range, linear area, linearity, sensitivity of the active and passive suspension inclination sensor are revealed, and the performance parameters such as resolution, response time, repetition rate, etc. are tested, and the debugging of the active and passive suspension inclination sensor is completed;

[0057] Step 3, actual test of active and passive suspended inclinometer. By adjusting the depth micrometer 10, change and record the actual tilt angle, and at the same time record the measured angle of the active and passive suspended inclinometer based on the performance parameters determined during the debugging process, compare and analyze the actual tilt angle and the test angle, obtain the measurement accuracy, and complete the actual test of the active and passive suspended inclinometer. Specifically: First, the depth micrometer is used to change the rising height of the plate. When the depth micrometer is not moved, the rising height of the plate is unchanged, and the tilt angle of the plate is unchanged at this time. Through θ 实际 =arctan(h / l), where h is the rising height of the plate; l is the horizontal distance between the depth micrometer and the hinge, which is a fixed value. It can be understood that the depth micrometer is fixed at a position with a horizontal distance of l from the hinge to calculate the actual tilt angle of the plate. Next, place the sensor on the plate. The sensor outputs the tilt angle measured by the sensor according to the curve and other performance parameters obtained during the debugging process in step 2. According to formula (4), formula (4) refers to the input and output curve of the sensor. At this time, compare and analyze the actual angle of the plate and the tilt angle measured by the sensor to obtain the sensor accuracy. Finally, by continuously adjusting the depth micrometer, the rising height h of the plate can be changed, and the actual tilt angle of the plate at any time can be obtained. At the same time, the tilt angle obtained by the sensor at any time can also be obtained. By comparing and analyzing, the average value of the sensor accuracy can be obtained, and the actual test can be completed.

[0058] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An active and passive suspension inclination sensor, characterized in that: The invention comprises a support frame (1), a magnetic pole array (2), a suspension ring (3), a non-magnetic metal ring (4), a magnetic permeable core (5), an excitation coil (6), a photoelectric displacement sensor (7), a controller (8), and a power amplifier (9); the magnetic pole array (2) is a tile-shaped array composed of N sector-shaped magnetic poles of the same shape, N is a natural number greater than 2, the magnetization direction of each sector-shaped magnetic pole is radiation magnetization and the magnetization intensity is equal, the magnetization directions of adjacent sector-shaped magnetic poles are arranged in two directions, namely, inward radiation and outward radiation, and they are naturally attracted together without external force; the suspension ring (3) and the non-magnetic metal ring (4) are assembled together by interference fit. The non-magnetic metal ring (4) is nested inside the suspension ring (3), and the suspension ring (3) is made of anti-magnetic material; the magnetic pole array (2) is located below the suspension ring (3), and generates an upward force on the suspension ring (3), so as to achieve the suspension of the suspension ring (3) and the non-magnetic metal ring (4); the magnetic core (5) passes through the non-magnetic metal ring (4), and the excitation coil (6) adopts a differential structure, that is, two groups of coils are used, which are symmetrically wound on the two ends of the magnetic core, and the excitation coils generate repulsive forces on the middle suspension ring (3) after being energized, and the magnetic core (5) is fixed by a support frame (1); the photoelectric displacement sensor (7) is arranged on the non-magnetic metal ring (4) and the excitation coil (6) is arranged on the non-magnetic metal ring (4). The two sides of the metal ring (4) are used to measure the position signal of the non-magnetic metal ring (4); the photoelectric displacement sensor (7) converts the collected position signal of the non-magnetic metal ring (4) into an electric signal in real time and transmits it to the controller (8); the controller (8) calculates the difference between the electric signal measured by the photoelectric displacement sensor (7) and the preset position electric signal to generate a control quantity that makes the difference zero and inputs it into the power amplifier (9); the preset position electric signal is a current signal set when the suspension ring (3) reaches the preset position when the tilt angle is zero, and the corresponding control current is generated through the amplification effect of the power amplifier (9); the power amplifier (9) The control current is processed by the addition circuit and the subtraction circuit to generate two signals with a difference of twice the control current. Two output currents are generated under the amplification of the power amplifier (9). The two output currents are respectively input into the upper and lower groups of excitation coils (6). The non-magnetic metal ring (4) is induced to generate a corresponding electromagnetic force by the control current in the excitation coil (6). The forces exerted on the non-magnetic metal ring (4) by the two groups of excitation coils (6) are in opposite directions. The resultant force exerted on the non-magnetic metal ring (4) is the difference between the two forces, so that the position of the non-magnetic metal ring (4) changes until the non-magnetic metal ring (4) stabilizes at a preset position.

2. The active and passive suspension inclination sensor according to claim 1, characterized in that: The magnetic pole array (2) may also be arranged in a "Halbach" arrangement, that is, the magnetization direction of the sector-shaped magnetic poles is radiating outwards, and is arranged in a counterclockwise circumferential direction, radiating inwards, and clockwise circumferential direction in sequence.

3. An active and passive suspension inclination sensor according to claim 1 or 2, characterized in that: The preset position is a position where the suspension ring (3) is equidistant from the two photoelectric displacement sensors.

4. An active and passive suspension inclination sensor according to claim 1 or 2, characterized in that: The number of N is 5.

5. An active and passive suspension inclination sensor according to claim 1 or 2, characterized in that: The inner diameter of the suspension ring (3) is slightly smaller than the outer diameter of the non-magnetic metal ring (4), and the difference between the two is kept below 0.1 mm. The interference fit is achieved by using a shrink sleeve.

6. An active and passive suspension type inclination sensor according to claim 1 or 2, characterized in that: The length of the suspension ring (3) is the same as that of the non-magnetic metal ring (4), and the ratio of the length of the magnetic pole array (2) to the length of the suspension ring (3) or the length of the non-magnetic metal ring (4) is greater than or equal to 3.

7. An active and passive suspension inclination sensor according to claim 1 or 2, characterized in that: There are two non-magnetic metal rings (4) of the same size and shape, which are respectively aligned with the two ends of the suspension ring (3); the ratio of the length of the suspension ring (3) to the length of a single non-magnetic metal ring (4) is greater than 2.

8. An active and passive suspension type inclination sensor according to claim 1 or 2, characterized in that: The ratio of the wall thickness of the suspension ring (3) to the wall thickness of the non-magnetic metal ring (4) is greater than 1.

9. An active and passive suspension type inclination sensor according to claim 1 or 2, characterized in that: The inclination measurement model of the active and passive suspension inclination sensor is: F 感电 =Gsinθ=mgsinθ (3) Wherein, formula (1) is an expression of the induced electromagnetic force, K is an electromagnetic force coefficient, and when the moving position of the non-magnetic metal ring during the angle change is not large relative to the preset position, it can be regarded as a constant, and its magnitude is determined by the frequency of the excitation current in the excitation coil (6), the material properties of the non-magnetic metal ring (4), and the mutual inductance coefficient between the excitation coil (6) and the non-magnetic metal ring (4); I0+I z , I0-I z are the total current amplitudes flowing through the excitation coil (6) at both ends of the permeable core (5), where I0 is the bias current amplitude of the excitation coil, I z is the control current amplitude; z0 is the preset initial position, z k is the movement amount of the non-magnetic metal ring (4) relative to the preset initial position; m is the sum of the masses of the suspension ring (3) and the non-magnetic metal ring (4); and θ is the tilt angle.

10. The testing method of the active and passive suspension type inclination sensor according to any one of claims 1 to 9, characterized in that: It includes the following three steps: Step 1, installing the active and passive suspension type inclination sensor, firstly passing the magnetic core (5) through the non-magnetic metal ring (4) which is interference fit with the suspension ring (3), winding the excitation coil (6) of the differential structure around the two ends of the magnetic core (5), fixing the magnetic core (5), adjusting the distance between the magnetic pole array (2) and the suspension ring, and after the suspension ring (3) is stably suspended and has no contact with the magnetic core (5), fixing the magnetic pole array (2), adjusting the position of the photoelectric displacement sensor (7) so that the laser emitted by it is aligned with the non-magnetic metal ring (4), ensuring that the distance between the photoelectric displacement sensor (7) and the non-magnetic metal ring (4) is within the linear working area of ​​the photoelectric displacement sensor (7), and completing the installation of the active and passive suspension type inclination sensor; Step 2, debugging the active and passive suspended inclination sensor, changing the size of the inclination angle by adjusting the depth micrometer (10), measuring and recording the size of the output current of the power amplifier at this time, drawing a curve of the output current changing with the inclination angle, repeating the experiment for many times, obtaining an average curve, revealing the measurement range, linear region, linearity, and sensitivity of the active and passive suspended inclination sensor, testing the resolution, response time, and repetition rate performance parameters, and completing the debugging of the active and passive suspended inclination sensor; Step 3, testing the active and passive suspended inclination sensor, changing and recording the actual inclination angle by adjusting the depth micrometer (10), and recording the measured angle measured by the active and passive suspended inclination sensor based on the performance parameters determined in the debugging process, comparing and analyzing the actual inclination angle and the test angle, obtaining the measurement accuracy, and completing the actual test of the active and passive suspended inclination sensor; specifically, firstly, changing the rising height of the plate by the depth micrometer, when the depth micrometer is not moved, the rising height of the plate is unchanged, and the inclination angle of the plate is unchanged at this time, by θ 实际 =arctan(h / l), where h is the rising height of the plate; l is the horizontal distance between the depth micrometer and the hinge, and the actual tilt angle of the plate is calculated; then, the sensor is placed on the plate, and the sensor outputs the tilt angle measured by the sensor according to the curve performance parameters obtained during the debugging process in step 2; at this time, the actual angle of the plate and the tilt angle measured by the sensor are compared and analyzed to obtain the sensor accuracy; finally, by continuously adjusting the depth micrometer and changing the rising height h of the plate, the actual tilt angle of the plate at any time can be obtained, and the tilt angle obtained by the sensor at any time can also be obtained. By comparing and analyzing, the average value of the sensor accuracy is obtained to complete the actual test.

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