CN113899442A - Ultra-low frequency velocity sensor, sensor system and vibration velocity measuring method - Google Patents

Ultra-low frequency velocity sensor, sensor system and vibration velocity measuring method Download PDF

Info

Publication number
CN113899442A
CN113899442A CN202111173215.XA CN202111173215A CN113899442A CN 113899442 A CN113899442 A CN 113899442A CN 202111173215 A CN202111173215 A CN 202111173215A CN 113899442 A CN113899442 A CN 113899442A
Authority
CN
China
Prior art keywords
vibration
mass
annular
coil
permanent magnet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
CN202111173215.XA
Other languages
Chinese (zh)
Inventor
周振华
刘彦莹
刘志强
江伟
凌金城
刘鑫
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Changsha University of Science and Technology
Original Assignee
Changsha University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Changsha University of Science and Technology filed Critical Changsha University of Science and Technology
Priority to CN202111173215.XA priority Critical patent/CN113899442A/en
Publication of CN113899442A publication Critical patent/CN113899442A/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H11/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties
    • G01H11/02—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties by magnetic means, e.g. reluctance

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Abstract

The invention belongs to the technical field of vibration sensors, and particularly relates to an ultralow frequency speed sensor, a sensor system and a vibration speed measuring method, wherein the ultralow frequency speed sensor comprises a shell, a vibration measuring mass, a negative rigidity unit with negative rigidity characteristic and an elastic mass unit; the negative stiffness unit comprises an annular coil and an annular permanent magnet, and the annular coil is connected with the vibration measurement mass and surrounds the vibration measurement mass; the annular permanent magnet is connected with the shell and surrounds the annular coil; a gap is reserved between the annular permanent magnet and the annular coil; two ends of the elastic mass unit are respectively connected with the shell; the vibration measuring mass is connected with the elastic mass unit. The ultra-low frequency speed sensor provided by the invention has ultra-low natural frequency and simple structure.

Description

Ultra-low frequency velocity sensor, sensor system and vibration velocity measuring method
Technical Field
The invention belongs to the technical field of vibration sensors, and particularly relates to an ultralow frequency speed sensor, a sensor system and a vibration speed measuring method.
Background
In the precision manufacturing and processing technology of semiconductors and the like, the processing precision of the precision processing technology reaches the nanometer level, and the vibration of the environment can influence the precision of processing equipment; in the aerospace field, vibration signals of an engine of a space shuttle are important judgment bases for fault diagnosis and health state judgment of the space shuttle; in the fields of earthquake and tsunami monitoring and early warning, geological exploration and the like, the monitoring and exploration are realized by measuring the ultralow frequency vibration below the earth surface. Therefore, the method has great significance for vibration measurement, and simultaneously, higher requirements are put forward for the ultra-low frequency vibration measurement technology.
The speed sensor has a typical high-pass characteristic in a measuring frequency band due to the restriction of a mechanical structure, and particularly when an ultra-low frequency vibration signal is measured, the vibration signal lower than the natural frequency of the sensor cannot be measured due to the limitation of the lower measuring limit of the sensor. In order to realize the measurement of the ultra-low frequency vibration signal, the ultra-low frequency lower limit extension of the sensor is generally realized by performing ultra-low frequency compensation on the sensor. At present, the method of externally connecting a series compensation circuit is the most widely used low-frequency expansion method, and includes the steps of firstly performing parameter identification on the existing sensor to obtain a transfer function of the existing sensor, then designing the series compensation circuit to enable a numerator of the transfer function of the compensation circuit to be cancelled with a denominator of the transfer function of a mathematical model of the sensor, wherein the denominator part of the transfer function of the compensation circuit is changed into the denominator of the transfer function of the sensor after expansion, an original zero point of the sensor is maintained unchanged, and a pole of the zero point is the pole of the compensation circuit. This results in a compensated sensor transfer function with a lower natural frequency, which widens the measurement range of the sensor. However, low-frequency expansion is realized through an external compensation link, the compensation link is relatively complex, and once the compensation link is designed, the natural frequency of the sensor cannot be modified, so that the applicability of the sensor is limited to a certain extent.
The patent with publication number "CN 201510724219.0" discloses an ultralow frequency implementation method for an electromagnetic intelligent digital vibration velocity sensor, which needs to calibrate a reference velocity in an ultralow frequency band, and the interval frequency band of the calibrated reference velocity needs to be small enough to implement accurate measurement, and realizes ultralow frequency expansion through an external compensation link, and the compensation and frequency adjustment are relatively complex. Therefore, it is desirable to provide an ultra-low frequency speed sensor having a simple structure and realizing an ultra-low natural frequency.
Disclosure of Invention
On one hand, the invention provides the ultralow frequency speed sensor with simple structure aiming at the problem that the ultralow frequency expansion is carried out by adopting a compensation link in the existing magnetoelectric speed sensor to realize the complexity of ultralow inherent frequency; on one hand, an ultra-low frequency speed sensor system is provided for accurately adjusting the natural frequency of the speed sensor; in another aspect, a method of measuring vibration velocity is provided using an ultra low frequency velocity sensor system.
The invention provides an ultralow frequency speed sensor, which comprises a shell, a vibration measuring mass, a negative rigidity unit with negative rigidity characteristic and an elastic mass unit;
the negative stiffness unit comprises an annular coil and an annular permanent magnet, and the annular coil is connected with the vibration measurement mass and surrounds the vibration measurement mass; the annular permanent magnet is connected with the shell and surrounds the annular coil; a gap is reserved between the annular permanent magnet and the annular coil;
the two ends of the outer side of the elastic mass unit are respectively connected with the shell; the vibration measuring mass is connected with the elastic mass unit.
In this configuration, the elastic mass element provides the total stiffness k of the spring-mass system; the magnetic field generated by the annular permanent magnet and the magnetic field generated by the current in the annular coil interact to form a negative rigidity unit, so that the negative rigidity k of the system is providedn(ii) a The total mass of the spring-mass system is m, and the natural frequency of the velocity sensor can be expressed as:
Figure BDA0003293765580000021
i.e. the speed sensor can be made to have an ultra low frequency by adjusting the current in the toroid.
Further, the elastic mass unit comprises a first elastic element and a second elastic element; two ends of the first elastic element are respectively connected with the shell; two ends of the second elastic element are respectively connected with the shell; and two ends of the vibration measuring mass are respectively connected with the first elastic element and the second elastic element.
Further, the first elastic element and the second elastic element are respectively leaf springs made of non-ferromagnetic materials.
Furthermore, the shell, the annular permanent magnet, the annular coil and the vibration measuring mass are coaxially arranged.
Further, under the non-working state, the mass center of the annular coil, the mass center of the vibration measuring mass and the mass center of the annular permanent magnet are on the same horizontal plane.
The invention provides an ultra-low frequency speed sensor system, which comprises the ultra-low frequency speed sensor and a natural frequency adjusting system;
the natural frequency adjustment system includes:
the acquisition unit is used for acquiring the expected current value of the annular coil corresponding to the expected natural frequency;
a current detection unit for detecting an actual current value in the loop coil;
and the adjusting unit is used for applying a compensation current to the annular coil according to the difference value between the expected current value and the actual current value so as to reduce the natural frequency of the sensor system.
When the natural frequency of the sensor needs to be adjusted, an expected current value corresponding to the natural frequency to be adjusted is determined, and compensation current is applied to the annular coil according to a difference value between the expected current value and the current detection unit, so that an actual current value is equal to the expected current value, and the natural frequency of the sensor is accurately adjusted.
Further, the adjusting unit includes:
the controller is used for acquiring an error signal according to the difference value between the expected current value and the actual current value and converting the error signal into a control quantity;
the control quantity duty ratio conversion unit is used for converting the control quantity into the duty ratio of the PWM signal and generating a corresponding PWM signal;
and an H-bridge driving circuit for applying a compensation current to the loop coil according to the PWM signal.
Furthermore, a low-pass filter is arranged between the H-bridge driving circuit and the annular coil and used for eliminating high-frequency voltage signals.
The invention provides a method for measuring the vibration speed of a measured object by using an ultralow frequency speed sensor system, which comprises the following steps:
when the object to be measured vibrates, the compensation current of the adjusting unit enables the system to have negative rigidity property, and the natural frequency of the system is reduced to be lower than that of the vibration signal of the object to be measured;
obtaining a difference value between the expected current value and the actual current value, and obtaining the relative vibration speed between the annular coil and the annular permanent magnet according to the difference value:
Figure BDA0003293765580000031
wherein the content of the first and second substances,
Figure BDA0003293765580000032
representing the velocity of the toroid;
Figure BDA0003293765580000033
representing the vibration speed of the measured object and the vibration speed of the annular permanent magnet;
obtaining the vibration velocity of the measured object
Figure BDA0003293765580000034
Because the vibration frequency of the measured object is higher than the natural frequency of the system mass block, the system has
Figure BDA0003293765580000035
The difference value between the expected current value and the actual current value is obtained in the measuring method, namely the induced current value generated by the relative displacement of the annular coil and the annular permanent magnet, and the induced current value and the relative vibration speed are obtained
Figure BDA0003293765580000036
In direct proportion, the relative vibration speed between the annular coil and the annular permanent magnet can be obtained through the induced current value
Figure BDA0003293765580000037
Since the vibration frequency of the vibration signal of the object to be measured is higher than the natural frequency of the sensor, the vibration velocity of the object to be measured relative to the ground is equal to the vibration velocity of the object to be measured relative to the system, i.e. the vibration frequency of the object to be measured relative to the system
Figure BDA0003293765580000038
Numerical value of (1)
Figure BDA0003293765580000039
The values of the two are equal, so that the measurement of the vibration speed of the measured object can be realized.
Has the advantages that:
the invention provides an ultra-low frequency speed sensor system which comprises the following components:
1. the speed sensor can have ultralow frequency by adjusting the current in the annular coil, so that the natural frequency of the sensor can be adjusted; the natural frequency is adjusted by adjusting the current, so that the structure of the sensor is simpler, and the application range of the sensor is wider;
2. the induction current value is the error value between the actual current value and the expected current value, and the relative vibration speed between the annular coil and the annular permanent magnet can be obtained through the error value
Figure BDA00032937655800000310
Due to vibration signals of the object to be measured
Figure BDA00032937655800000311
Is lower than the natural frequency of the sensor,
Figure BDA00032937655800000312
numerical value of (1)
Figure BDA00032937655800000313
The values of the two are equal, so that the measurement of the vibration speed of the measured object can be realized.
Drawings
The invention is described in further detail below with reference to the figures and specific embodiments.
Fig. 1a is a mechanical structure external view of the ultra low frequency speed sensor of example 1.
Fig. 1b is a plan view of the mechanical structure of the ultra low frequency speed sensor of example 1.
Fig. 1c is a side view of the mechanical structure of the ultra low frequency speed sensor of example 1.
FIG. 2 is a cross-sectional view taken along A-A of FIG. 1 b.
FIG. 3 is a cross-sectional view taken along line B-B of FIG. 1 c.
Fig. 4 is a structural equivalent mechanical model of the ultra low frequency velocity sensor of example 1.
FIG. 5 is a regulation relation between the current of the toroidal coil and the electromagnetic negative stiffness unit.
FIG. 6 is a graph of the relative velocity of the toroidal coil and the toroidal permanent magnet
Figure BDA0003293765580000041
And the vibration speed of the object to be measured
Figure BDA0003293765580000042
Frequency response curve.
Fig. 7 is a control loop schematic of an ultra low frequency speed sensor system.
Reference numerals: 1. a housing; 2. measuring the vibration quality; 31. an annular permanent magnet; 32. a loop coil; 41. a first elastic element; 42. a second elastic element; 51. a first connecting column; 52. a second connecting column; 6. and a terminal.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Example 1
Referring to fig. 2 and 3, the present embodiment provides an ultra-low frequency speed sensor, which includes a housing 1, a vibration measuring mass 2, a negative stiffness unit, and an elastic mass unit.
The shell 1 comprises a shell body and a cover body, the cover body comprises an upper end cover and a lower end cover, and two ends of the shell body are respectively connected with the upper end cover and the lower end cover.
The elastic mass unit comprises a first elastic element 41 and a second elastic element 42, and two ends of the second elastic element 42 are respectively connected with the shell; in order to eliminate the influence of the magnetic field on the elasticity, the first elastic element 41 and the second elastic element 42 are respectively made of a leaf spring made of a non-ferromagnetic material such as copper.
One end of the vibration measuring mass 2 is connected with the first elastic element 41 through a first connecting column 51; the other end of the seismic mass 2 is connected to the second spring element 42 via a second connecting column 52.
The negative stiffness unit comprises an annular coil 32 and an annular permanent magnet 31, and the magnetization direction of the annular permanent magnet 31 is axial magnetization. The annular coil 32 is connected with the vibration measuring mass 2 and surrounds the vibration measuring mass 2; the annular permanent magnet 31 is connected with the shell and surrounds the annular coil 32; a gap is reserved between the annular permanent magnet 31 and the annular coil 32; the two ends of the annular coil 32 are respectively provided with a wiring terminal 6, and current is input and output through the wiring terminals 6.
The shell 1, the vibration measuring mass 2, the annular coil 32 and the annular permanent magnet 31 are coaxially arranged. In this embodiment, in the non-operating equilibrium state, the center of mass of the annular coil 32, the center of mass of the vibration measuring mass 2, and the center of mass of the annular permanent magnet 31 are on the same horizontal plane.
The elastic element, the annular coil 32 and the vibration measuring mass 2 form a single-degree-of-freedom spring mass system; the toroidal coil 32, the vibration measuring mass 2, the first connecting column 51 and the second connecting column 52 together form the total mass m of the single-degree-of-freedom spring mass system, the first elastic element 41 and the second elastic element 42 provide the total stiffness k of the single-degree-of-freedom spring mass system, and the mechanical damping provides structural damping for the first elastic element 41 and the second elastic element 42.
In this embodiment, by setting the magnetization direction of the annular permanent magnet 31 and the current direction of the annular coil 32, and specifically, the magnetization direction and the current direction of the annular coil 32 as shown in fig. 2, the magnetic field generated by the current in the annular coil 32 interacts with the magnetic field of the annular permanent magnet 31 to generate the negative stiffness characteristic; the negative rigidity k of the electromagnetic negative rigidity unit formed by the annular coil 32 and the annular permanent magnet 31 can be adjusted by controlling the current of the annular coil 32nNegative stiffness k generated by an electromagnetic negative stiffness unitnIn parallel with the total stiffness k of the spring mass system, the natural frequency of the velocity sensor can be expressed as:
Figure BDA0003293765580000051
thus, by adjusting the current in the toroid 32, it is made electromagneticNegative stiffness k of negative stiffness unitnLowering so that the speed sensor has an ultra-low natural frequency; the ultra-low frequency speed sensor has a simple structure and adjustable natural frequency, and the adjustment of the natural frequency of the sensor structure can be realized through the single annular coil 32.
Example 2
Referring to fig. 7, the present implementation provides an ultra low frequency speed sensor system including an ultra low frequency speed sensor, and a natural frequency tuning system;
the natural frequency adjustment system includes:
an acquisition unit for acquiring a desired current value of the loop coil 32 corresponding to a desired natural frequency;
a current detection unit for detecting an actual current value in the loop coil 32;
the adjusting unit comprises a controller, a control quantity duty ratio conversion unit and an H-bridge driving circuit; the controller is used for acquiring an error signal according to the difference value between the expected current value and the actual current value and converting the error signal into a control quantity; the control quantity duty ratio conversion unit is used for converting the control quantity into the duty ratio of the PWM signal and generating a corresponding PWM signal; and an H-bridge drive circuit for applying a compensation current to the loop coil 32 according to the PWM signal to lower the natural frequency of the sensor system.
A low-pass filter is arranged between the H-bridge drive circuit and the toroidal coil 32 for eliminating high-frequency voltage signals.
The acquisition unit, the current detection unit, the adjustment unit, the low-pass filter and the annular coil 32 form a current closed-loop control system of the annular coil 32, so that the actual current value of the annular coil 32 can be kept consistent with the expected current value, and the natural frequency of the speed sensor can be accurately adjusted.
In this embodiment, when the natural frequency of the sensor needs to be adjusted, it is first necessary to determine a desired current value corresponding to the desired natural frequency that needs to be adjusted, that is, a desired current value within the loop coil, which determines the negative stiffness characteristic in the negative stiffness element, and thus the natural frequency value of the sensor. Therefore, in the present embodiment, the compensation current is applied to the loop coil by the adjustment unit, so that the current in the loop coil can reach a desired current value.
Specifically, in the present embodiment, the current detection unit detects the loop coil in real time, so as to obtain the actual current value in the loop coil; acquiring a difference value between an expected current value and an actual current value by using a controller so as to acquire an error signal, and converting the error signal into a control quantity; generating a corresponding PWM signal through a control quantity duty ratio conversion unit; and finally, applying compensation current to the annular coil by using an H-bridge driving circuit according to the PWM signal, so that the current in the annular coil reaches an expected current value, and the accurate adjustment of the natural frequency of the sensor is realized.
Example 3
A method for measuring the vibration velocity of a measured object by using an ultralow frequency velocity sensor system comprises the following steps:
when the object to be measured vibrates, the compensation current of the adjusting unit enables the system to have negative rigidity property, and the natural frequency of the system is reduced to be lower than that of the vibration signal of the object to be measured;
the difference between the desired current value and the actual current value is obtained, and the relative vibration speed between the annular coil 32 and the annular permanent magnet 31 is obtained according to the difference:
Figure BDA0003293765580000061
wherein the content of the first and second substances,
Figure BDA0003293765580000062
represents the vibration speed of the toroidal coil 32;
Figure BDA0003293765580000063
representing the vibration speed of the measured object and the vibration speed of the annular permanent magnet 31;
obtaining the vibration velocity of the measured object
Figure BDA0003293765580000064
Figure BDA0003293765580000065
In this embodiment, referring to FIG. 4, in the equivalent mechanical model of the velocity sensor, xiIs the vibrational displacement, x, of the object to be measuredoFor the response displacement of the vibration measuring mass 2 of the sensor, the relative velocity between the whole annular coil 32 and the annular permanent magnet 31 can be obtained
Figure BDA0003293765580000071
And velocity of the object to be measured
Figure BDA00032937655800000714
The transfer function between is:
Figure BDA0003293765580000072
in the formula: m is the total mass of the single degree of freedom spring mass system, k is the total stiffness of the spring mass system, c is the mechanical damping, k is the total stiffness of the spring mass systemnAnd s is a complex variable, and is alpha + j alpha omega.
The corresponding frequency response curve is shown in fig. 6, and it is obvious that when the frequency of the vibration of the measured object is higher than the natural frequency of the sensor, the relative velocity between the annular coil 32 and the annular permanent magnet 31
Figure BDA0003293765580000073
And the vibration speed of the object to be measured
Figure BDA0003293765580000074
Is 1, and thus the negative stiffness k of the electromagnetic negative stiffness unit is adjusted by adjusting the current in the toroid 32nThe relation curve of the current in the annular coil 32 and the negative stiffness of the electromagnetic negative stiffness unit is referred to as 5, so that the natural frequency of the ultra-low frequency speed sensor system is adjusted to be lower than the frequency of the vibration signal of the measured object; the relative velocity between the toroidal coil 32 and the toroidal permanent magnet 31
Figure BDA0003293765580000075
And the vibration speed of the object to be measured
Figure BDA0003293765580000076
Are equal in value.
When the relative speed is generated between the annular coil 32 and the annular permanent magnet 31
Figure BDA0003293765580000077
While the magnetic flux changes, thereby generating an induced current, a rate of change and a relative speed of the magnetic flux
Figure BDA0003293765580000078
Proportional to the magnetic flux change rate, and the induced current is proportional to the magnetic flux change rate, so that the relative speed generated between the annular coil 32 and the annular permanent magnet 31 can be calculated by acquiring the induced current
Figure BDA0003293765580000079
When the object to be measured does not vibrate, the relative displacement x of the annular coil 32 and the annular permanent magnet 31o--xiAnd relative velocity
Figure BDA00032937655800000710
Therefore, the induced electromotive force between the annular coil 32 and the annular permanent magnet 31 is zero, and at this time, the error signal of the current obtained by subtracting the desired current value and the current value obtained by the measuring module is zero.
When the object to be measured vibrates, the relative displacement x between the annular coil 32 and the annular permanent magnet 31o-xiAnd relative velocity
Figure BDA00032937655800000711
Will not be zero, the toroidal coil 32 and the toroidal permanent magnet 31 will produce a relative velocity
Figure BDA00032937655800000712
Since the magnetic field generated by the annular permanent magnet 31 is not uniform, the annular coil 32 moves thereinAt this time, an induced electromotive force is generated, and an induced current is generated in the toroidal coil 32, resulting in a change in the current in the toroidal coil 32, and therefore, the current in the toroidal coil 32 is a combined result of the voltage passing through the low pass filter and the action of the induced electromotive force. The current difference obtained by subtracting the expected current value of the input end of the annular coil 32 acquired by the acquisition unit and the current value acquired by the current detection unit is no longer zero, and the current difference is relative speed
Figure BDA00032937655800000713
Induced current generated by the induced electromotive force, and the magnitude and relative speed of the induced current
Figure BDA0003293765580000081
Proportional ratio, therefore, the relative speed can be obtained by extracting the current difference
Figure BDA0003293765580000082
When the object to be measured vibrates
Figure BDA0003293765580000083
Is lower than the natural frequency of the sensor,
Figure BDA0003293765580000084
numerical value of (1)
Figure BDA0003293765580000085
The numerical values are equal, namely the vibration speed of the measured object can be measured by the above mode.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the spirit or scope of the invention.

Claims (9)

1. An ultra-low frequency speed sensor is characterized by comprising a shell (1), a vibration measuring mass (2), a negative rigidity unit with negative rigidity characteristic and an elastic mass unit;
the negative stiffness unit comprises an annular coil (32) and an annular permanent magnet (31), and the annular coil (32) is connected with the vibration measurement mass (2) and surrounds the vibration measurement mass (2); the annular permanent magnet (31) is connected with the shell and surrounds the annular coil (32); a gap is reserved between the annular permanent magnet (31) and the annular coil (32);
two ends of the elastic mass unit are respectively connected with the shell; the vibration measuring mass (2) is connected with the elastic mass unit.
2. An ultra low frequency speed sensor according to claim 1, wherein said elastic mass unit comprises a first elastic element (41) and a second elastic element (42); two ends of the first elastic element (41) are respectively connected with the shell; two ends of the second elastic element (42) are respectively connected with the shell; and two ends of the vibration measuring mass (2) are respectively connected with the first elastic element (41) and the second elastic element (42).
3. The ultra low frequency speed sensor according to claim 2, wherein the first elastic element (41) and the second elastic element (42) are leaf springs made of non-ferromagnetic material.
4. The ultra low frequency speed sensor according to claim 1, wherein the housing (1), the annular permanent magnet (31), the annular coil (32) and the vibration measuring mass (2) are coaxially mounted.
5. An ultra low frequency speed sensor according to claim 1, wherein the center of mass of the toroidal coil (32), the center of mass of the vibration sensing mass (2), and the center of mass of the toroidal permanent magnet (31) are in the same horizontal plane in the non-operating state.
6. An ultra low frequency speed sensor system, characterized by: comprising an ultra low frequency speed sensor according to any one of claims 1 to 5, and a natural frequency tuning system;
the natural frequency adjustment system includes:
an acquisition unit for acquiring a desired current value of the loop coil (32) corresponding to a desired natural frequency;
a current detection unit for detecting an actual current value in the loop coil (32);
and an adjusting unit for applying a compensation current to the annular coil (32) according to the difference between the expected current value and the actual current value, so as to reduce the natural frequency of the sensor system.
7. The ultra low frequency speed sensor system of claim 6, wherein: the adjusting unit includes:
the controller is used for acquiring an error signal according to the difference value between the expected current value and the actual current value and converting the error signal into a control quantity;
the control quantity duty ratio conversion unit is used for converting the control quantity into the duty ratio of the PWM signal and generating a corresponding PWM signal;
and an H-bridge drive circuit for applying a compensation current to the loop coil (32) in accordance with the PWM signal.
8. The ultra low frequency speed sensor system of claim 7, wherein: and a low-pass filter is arranged between the H-bridge driving circuit and the annular coil (32) and is used for eliminating high-frequency voltage signals.
9. A method for measuring vibration velocity using the ultra low frequency velocity sensor system according to any one of claims 6 to 8, comprising:
when the object to be measured vibrates, the compensation current of the adjusting unit enables the system to have negative rigidity property, and the natural frequency of the system is reduced to be lower than that of the vibration signal of the object to be measured;
obtaining expected current value and actual current valueA difference between the current values, from which a relative vibration speed between the annular coil (32) and the annular permanent magnet (31) is obtained:
Figure FDA0003293765570000021
wherein the content of the first and second substances,
Figure FDA0003293765570000022
representing the speed of the toroidal coil (32);
Figure FDA0003293765570000023
representing the vibration speed of the object to be measured and the vibration speed of the annular permanent magnet (31);
obtaining the vibration velocity of the measured object
Figure FDA0003293765570000024
Figure FDA0003293765570000025
CN202111173215.XA 2021-10-08 2021-10-08 Ultra-low frequency velocity sensor, sensor system and vibration velocity measuring method Withdrawn CN113899442A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111173215.XA CN113899442A (en) 2021-10-08 2021-10-08 Ultra-low frequency velocity sensor, sensor system and vibration velocity measuring method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111173215.XA CN113899442A (en) 2021-10-08 2021-10-08 Ultra-low frequency velocity sensor, sensor system and vibration velocity measuring method

Publications (1)

Publication Number Publication Date
CN113899442A true CN113899442A (en) 2022-01-07

Family

ID=79190491

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111173215.XA Withdrawn CN113899442A (en) 2021-10-08 2021-10-08 Ultra-low frequency velocity sensor, sensor system and vibration velocity measuring method

Country Status (1)

Country Link
CN (1) CN113899442A (en)

Similar Documents

Publication Publication Date Title
US7347097B2 (en) Servo compensating accelerometer
JP3786887B2 (en) Magnetic detector
US6075754A (en) Single-coil force balance velocity geophone
CN104677483B (en) A kind of digitized magneto-electric low-frequency shock transducer system
JP2717231B2 (en) Underground hearing system
US9100759B2 (en) Loudspeaker driver with sensing coils for sensing the position and velocity of a voice-coil
JPH06109515A (en) Mass flow rate measuring method
US20170234940A1 (en) Magnetic sensor including a lorentz force transducer driven at a frequency different from the resonance frequency, and method for driving a lorentz force transducer
US4051718A (en) Apparatus for measuring the velocity of low frequency vibrations
US9035648B2 (en) Magnetic sensor characterization
US5560115A (en) Gimbaled magnetometer with inductive coupling
CN113899442A (en) Ultra-low frequency velocity sensor, sensor system and vibration velocity measuring method
RU95832U1 (en) VIBRATION MEASUREMENT DEVICE
GB2461207A (en) Magnetic sensor with compensation for lead and coil resistance
RU2207522C2 (en) Apparatus for measuring vibrations
EP1066533B1 (en) Apparatus for improving performance of a force balance accelerometer based on a single-coil velocity geophone
CN111879988A (en) Device and method for detecting passive current in low-frequency mechanical vibration environment
CN108267073B (en) Low-frequency vibration displacement sensor and detection method thereof
CN103575383A (en) Low-frequency multi-output passive servo vibration sensor capable of simultaneously measuring acceleration and velocity
CN106768282B (en) On-site calibration system for magneto-electric sensor
US11953635B2 (en) Seismometer with high sensitivity, broadband and all-dip
JP3240660U (en) accelerometer with geophone
JPS6193907A (en) Angular-velocity sensor device
CN221239062U (en) SIP magnetic sensor
Kohl et al. Extending the range of geophones by negative impedance converter

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
WW01 Invention patent application withdrawn after publication

Application publication date: 20220107

WW01 Invention patent application withdrawn after publication