CN114060451B - Nonlinear-magnetorheological self-tuning vibration absorber - Google Patents

Abstract

The invention discloses a nonlinear-magnetorheological self-tuning vibration absorber, comprising an acceleration sensor, an electronic control unit, a driving module and a vibration absorber. The acceleration sensor senses the vibration acceleration of a hydraulic pump and serves as a vibration signal for closed-loop control It is transmitted to the electronic control unit; the electronic control unit is used to obtain an error signal according to the motor speed value and the vibration signal provided by the acceleration sensor, and compare it with a predetermined amplitude to obtain an error signal, thereby generating and outputting a control signal; After controlling the signal, a drive signal with a certain amplitude and frequency is output; the vibration absorber is installed on the front end cover of the hydraulic pump to receive the drive signal and generate electromagnetic damping to offset the excitation force transmitted by the motor to the hydraulic pump. By sensing the vibration response of the hydraulic pump in real time, the invention controls the vibration absorber to apply electromagnetic damping to offset the excitation force transmitted by the motor, and has obvious vibration reduction effect, low cost, small size and flexible use.

Description

A nonlinear-magnetorheological self-tuning vibration absorber

technical field

The invention belongs to a vibration reduction and energy dissipation device in the technical field of structural vibration, in particular to a nonlinear-magnetorheological self-tuning vibration absorber.

Background technique

According to the characteristics of the stiffness unit or damping unit, the energy dissipation and vibration damping device can be divided into two types: linear and nonlinear. Dynamic vibration absorber (DVA), also known as tuned mass damper (TMD), which is widely used in engineering, is a passive vibration control device that is widely used. The excitation frequency of the system vibration is the same or close. The resonance principle is used to suppress the vibration of the system. As a linear damper, TMD can only play a good vibration reduction effect in a specific frequency band. However, the frequency of the external excitation and the power of the main junction Characteristics tend to change over time. At this time, the TMD will lose the vibration reduction efficiency, and even aggravate the vibration response of the main structure. Nonlinear Energy Sink (NES) has the advantages of small additional mass, wide vibration suppression frequency band, directional target energy transfer, high reliability, and strong robustness, which can effectively make up for the defects of TMD in the field of nonlinear vibration. However, the existing nonlinear energy traps (NES) are passively controlled and cannot be adjusted in time according to the characteristics of the external excitation and the changes of the vibration characteristics of the structure itself, and there are certain limitations. Therefore, the present invention combines the semi-active control technology with the NES passive control technology, and performs feedback control on the magnetic field environment of the magnetic liquid through the vibration characteristics to generate variable damping and consume the NES-magnetorheological dynamic vibration absorber absorbed from the hydraulic pipeline. Vibration energy to realize hybrid vibration control combining passive and semi-active.

Magnetic liquid is a long-term stable colloid, which is composed of base carrier liquid, micro/nano-scale magnetic particles and surfactants wrapped on the surface of magnetic particles. The second type of levitation characteristics of magnetic liquids means that the buoyancy force of magnets immersed in magnetic liquids is greater than the Archimedes buoyancy force, so the magnetic liquids can suspend the immersed magnets with a specific gravity greater than that of the magnetic liquids. The magnetic liquid damping shock absorber based on the second type of suspension characteristics of the magnetic liquid dissipates energy through friction and collision between the magnetic liquid and the shell, shear inside the magnetic liquid, and friction between the suspension and the magnetic liquid. Damping effect.

SUMMARY OF THE INVENTION

Technical problem: The purpose of the present invention is to propose a nonlinear-magnetorheological self-tuning vibration absorber, which realizes the semi-active transformation of nonlinear energy traps based on the second type of suspension characteristics of magnetic liquids, and can respond to external disturbances according to the structure. The response changes the magnetic field environment of the magnetic liquid in real time, resulting in variable damping. It can be widely used as a semi-active control in the field of vibration absorption and vibration reduction in the hydraulic system.

Technical solution: a nonlinear-magnetorheological self-tuning vibration absorber according to an embodiment of the present invention is composed of a vibration reduction system and a control system. The vibration reduction system includes a casing, a dynamic mass, a stator and a guide assembly; the measurement and control system includes a displacement Sensors, DSP controllers, current drivers.

The control system integrates a processor module, a digital-to-analog conversion module, a driver module and an acceleration sensor. The processor module analyzes and processes the acceleration signal of the acceleration sensor and outputs a digital control signal. The digital-to-analog conversion module converts the digital control signal output by the processor into an analog signal for controlling the driver module. The driver module adjusts according to the signal instructions of the processor module. The magnitude of the current in the excitation coil.

Further, the generation of the control signal specifically includes: a vibration signal, which is transmitted to the electronic control unit as a feedback signal.

Further, the acceleration sensor is installed at the power source of the hydraulic system, and is used to transmit the vibration signal at the power source to the electronic control unit as a feedback signal by sensing the vibration signal.

Determine the main order frequency of motor vibration from the obtained motor speed value;

Band-pass filtering is performed on the received vibration signal according to the frequency of the main vibration order, and the frequency components of the vibration signal near the main order of vibration are retained;

Judging the vibration of the received main-order frequency components, that is, when the vibration of the filtered vibration signal near the main-order frequency exceeds a predetermined amplitude, the semi-active control device starts to work and generates the control signal.

Further, the driving module is used to receive the control signal output by the electronic control unit, apply a certain gain to the control signal, and generate an alternating current with a certain amplitude and frequency as the driving signal to act on the vibration absorber, thereby generating electromagnetic damping. effect.

A nonlinear-magnetorheological self-tuning vibration absorber according to an embodiment of the present invention has the following beneficial effects for the related art:

(1) Based on the second type of suspension characteristics of magnetic liquids, the nonlinear stiffness is generated by the axial and radial suspension forces generated by the magnetic liquid under the action of a non-uniform magnetic field, so that the device can have the characteristics of targeted energy transfer with the mechanical structure, This transmission has the characteristics of fast transmission speed and one-way (irreversible), so the NES-magnetic hydrodynamic vibration absorber can efficiently capture the vibration energy of the main structure and transmit it to itself, with high energy dissipation efficiency and can quickly The mechanical energy of the mechanism vibration is converted into the heat energy generated by friction, and the effect of damping and vibration reduction is good;

(2) The device of the nonlinear energy trap only needs 5% to 10% of the main structure, and has the advantages of light weight, strong robustness, wide vibration reduction frequency band, simple structure, and convenient installation. In terms of nonlinear energy dissipation and vibration reduction Has a good application prospect.

(3) At present, most of the nonlinear energy trap devices designed based on the principle of targeted energy transfer are passively controlled, and this nonlinear energy trap device based on the suspension characteristics of magnetic liquid can be further realized by adjusting the damping size according to the characteristics of the main structure. Active control, with semi-active control combining passive and active, makes up for the disadvantage that passive control cannot be time-varying, and at the same time, reduces the problem of high energy consumption of semi-active control.

(4) The nonlinear-magnetorheological self-tuning vibration absorber only needs to modify the control algorithm to meet the vibration reduction requirements under different working conditions, with low cost and flexible use.

Additionally, advantages according to additional aspects of the invention will be set forth in part in the detailed description which follows, and some advantages will become apparent, or may be obtained by practice of the invention.

Description of drawings

FIG. 1 is a schematic diagram of a semi-active control device for vibration of a hydraulic system according to an embodiment of the present invention.

FIG. 2 is a schematic flowchart of the implementation of the control method for the semi-active control of the vibration absorber of the hydraulic system according to the embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a nonlinear-magnetorheological self-tuning vibration absorber according to an embodiment of the present invention.

4 is a schematic structural diagram of a guide assembly of a vibration absorber according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a dynamic mass structure of a vibration absorber according to an embodiment of the present invention.

FIG. 6 is a schematic structural diagram of a permanent magnet ring of a vibration absorber according to an embodiment of the present invention.

FIG. 7 is a schematic view of the stator structure of a vibration absorber according to an embodiment of the present invention

FIG. 8 is a schematic structural diagram of a vibration absorber housing according to an embodiment of the present invention

FIG. 9 is a schematic diagram of a mechanical model of a vibration absorber according to an embodiment of the present invention.

Reference number:

A non-linear-magnetorheological self-tuning vibration absorber 10,

Among them: 1. Guide assembly; 1-1, Upper limit block; 1-2, Guide shaft; 1-3, Lower limit block; 1-4, Lubrication groove; 2, Dynamic mass; 2-1, Upper end nut; 2 -2, permanent magnet ring; 2-3, magnetic conductive block; 2-4, permanent magnet ring cage; 2-5, bottom nut; 2-6, micro-nano magnetic composite fluid; 3, stator; 3-1, Coil holder; 3-2, Coil winding; 3-3, Copper coil; 3-4, Coil winding slot; 4, Vibration absorber shell; 4-1, Upper end cover; 4-2, Coil lead entry; 4-3 , Cylindrical shell; 4-4, heat dissipation hole; 4-5, lower end cover; 4-6, coil lead outlet; 4-7, sealing ring.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

A nonlinear-magnetorheological self-tuning vibration absorber 10 according to an embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 9 . The nonlinear-magnetorheological self-tuning vibration absorber 10 is one of the most promising hydraulic system vibration control devices, and will have wide application prospects in the field of hydraulic engineering.

With reference to Fig. 1, a nonlinear-magnetorheological self-tuning vibration absorber includes an acceleration sensor, an electronic control unit, a driving module and a damping vibration absorption module. The acceleration sensor senses the vibration acceleration of the power source of the hydraulic system, and transmits it to the electronic control unit as a closed-loop control vibration signal; the electronic control unit is used for the vibration signal provided by the motor speed value and the acceleration sensor. , and compare it with a predetermined amplitude to obtain an error signal, thereby generating and outputting a control signal; the drive module outputs a drive signal with a certain amplitude and frequency according to the received control signal; the vibration absorber is installed in the hydraulic pump It is used to receive the drive signal output by the drive module and generate a certain electromagnetic force, to control the magnetic viscosity effect of the micro-nano composite magnetic liquid, and to generate an electromagnetic damping effect to achieve the purpose of semi-active vibration control.

Specifically, the acceleration sensor is installed on the front end of the hydraulic pump and is used to sense the vibration signal at the hydraulic pump and transmit it to the electronic control unit as a feedback signal. The driving module is used for receiving the control signal output by the electronic control unit, applying a certain gain to the control signal, and generating an alternating current with a certain amplitude and frequency as the driving signal to act on the vibration absorber.

Specifically, the generation of the control signal specifically includes:

Determine the main order frequency of motor vibration based on the obtained motor speed value; carry out band-pass filtering on the received vibration signal according to the main order frequency of vibration, and retain the frequency components of the vibration signal near the main order of vibration; The vibration of the main-order frequency components is judged, that is, when the vibration of the filtered vibration signal near the main-order frequency exceeds a predetermined amplitude, the semi-active control device starts to work and generates the control signal.

Specifically, the electronic control unit of this embodiment receives the motor speed signal synchronously, determines the main order frequency of the motor vibration, and performs band-pass filtering on the vibration signal transmitted by the acceleration sensor according to the obtained main order frequency. , so as to retain the frequency components of the vibration signal near the frequency of the main order; the electronic control unit makes an error judgment on the amplitude of the filtered vibration signal near the frequency of the main order, if it exceeds the predetermined amplitude, it outputs a control command to the drive module, otherwise , does not output the control command; the drive module generates the drive signal to drive the vibration absorber to work according to the received control command; the vibration absorber outputs the electromagnetic driving force.

As shown in FIG. 3 , in this embodiment, the vibration absorber includes a guide assembly 1 , a dynamic mass 2 , a stator 3 , and a housing 4 . Both ends of the guide assembly 1 are threaded, and are connected with the end caps by means of threads. The dynamic mass 2 is in clearance fit with the guide assembly 1 and slides along the guide shaft 2 to consume vibration energy. The stator 3 is wound with copper coils 3-3 arranged in a sparse to dense distribution from top to bottom to form a gradient magnetic field, and both ends of the stator 3 are threadedly connected to the end caps. Heat dissipation holes are evenly distributed around the casing 4, and are screwed with the upper end cover 4-1 and the lower end cover 4-5.

As shown in FIG. 4 , the guide assembly 1 includes an upper limit block 1-1, a guide shaft 1-2, a lower limit block 1-3, and a lubrication groove 1-4. The guide shaft 1-2 passes through the permanent magnet ring holder 2-4, and the two form a moving secondary structure. Both ends of the guide shaft 1-2 are connected with the upper limit block 1-1, the lower limit block 1-3, the left end cover 4-1 and the right end cover 4-5 by screw connection. Wherein, the guide shafts 1-2 are non-magnetic conductive materials, and stainless steel materials (such as 304, 304L, 316, 316L, etc.) are used in the present invention, and the outer surfaces thereof are designed with lubricating grooves 1-4 whose structures are arc grooves and Spiral grooves, but not limited to the above two structures, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without contradicting each other. Its outer surface is required to have good surface roughness, and the guide shaft 1-2 is in clearance fit with the permanent magnet ring cage 2-4.

As shown in Figure 5, the dynamic mass 2 is composed of an upper nut 2-1, a permanent magnet ring 2-2, a magnetic conductive block 2-3, a permanent magnet ring holder 2-4, a lower nut 2-5, a micro-nano The magnetic compound liquid is composed of 2-6. The upper end nut 2-1 and the lower end nut 2-5 are mainly used to connect the permanent magnet ring 2-2 and the magnetic conducting block 2-3, so as to be fixed on the permanent magnet ring holder 2-4. The permanent magnet ring 2-2 adopts different structural types according to application requirements, such as cylindrical shape, truncated cone shape, etc., but is not limited to the above two structures. The different embodiments or examples described and features of the different embodiments or examples are combined and combined. The permanent magnet ring cage 2-4 is made of magnetic conductive material, and its inner hole and the guide shaft 1-2 form a static pressure support. "Friction effect" can reduce the friction force of the contact surface and improve the sensitivity of the dynamic mass 2 to vibration absorption.

As shown in Figure 6, the permanent magnet ring 2-2 is made of permanent magnet (such as NdFeB) material, and its outer diameter has different sizes. When installing, first install the magnetic conductive block 2-3 on the permanent magnet ring cage The middle part of 2-4 is divided into upper and lower ends in turn, and the small-diameter permanent magnet ring 2-2 is inserted into the permanent magnet ring holder 2-4, and the diameters of different permanent magnet rings 2-2 are sequentially increased and inserted into the permanent magnet ring. In the ring cage 2-4, a magnetic gradient from large to small is formed at the upper and lower ends.

As shown in FIG. 7 , the stator 3 includes a coil holder 3-1, a coil winding 3-2, a copper coil 3-3, and a coil winding slot 3-4. The coil winding 3-2 is composed of a copper coil 3-3 and a coil holder 3-1. The coil holder 3-1 has coil winding slots 3-3. Among them, the coil winding slots 3-3 are arranged in a sparse to dense distribution from top to bottom by the waist drum-shaped coil holder 3-1, and the coil winding 3-2 is placed in the coil winding slot 3-3 to form an electromagnetic field gradient distribution. The coil winding 3-2 is placed in the coil winding slot 3-3. The stator 3 is connected with the upper end cover 4-1 and the lower end cover 4-5 by bolts.

As shown in FIG. 8, the vibration absorber casing 4 includes an upper end cover 4-1, a coil lead inlet 4-2, a cylindrical casing 4-3, a heat dissipation hole 4-4, a lower end cover 4-5, and a coil lead outlet 4- 6. Sealing ring 4-7. The upper end cap 4-1 and the lower end cap 4-5 are both sealed with a sealing ring 4-7, and an interference fit is adopted to prevent leakage of the micro-nano magnetic composite liquid 2-6. Heat dissipation holes 4-4 are evenly distributed around the cylindrical shell 4-3 to achieve uniform dispersion of vibration heat energy, and its upper and lower ends are connected with the upper end cover 4-1 and the lower end cover 4-5 by screws.

As shown in Figure 2, the implementation principle of this embodiment includes the following steps:

Sensing of hydraulic pump vibration: The acceleration sensor is arranged at the end cover of the hydraulic pump to sense the vibration acceleration response of the hydraulic pump and feed it back to the electronic control unit as a vibration signal;

Main-order frequency generation: The electronic control unit receives the motor speed signal in real time to determine the main-order vibration frequency of the motor vibration;

Band-pass filtering processing: filter the vibration signal transmitted by the received acceleration sensor according to the main-order vibration frequency, and retain the frequency components of the vibration signal near the main-order frequency;

Error judgment step: when the amplitude of the filtered vibration signal in the vicinity of the main-order frequency exceeds a predetermined amplitude, it is determined that the active control system is working;

Control signal generation: According to the error judgment, determine the control signal to suppress the vibration of the seat rail;

Drive signal generation: According to the control signal, the drive module applies a certain gain to generate the drive signal;

The generation of driving electromagnetic force: the vibration absorber receives the driving signal, adjusts the current of the excitation coil, changes the magnetic field environment of the vibration absorber 10, and affects the shear force, dynamic mass 2 and micro-nano magnetic force inside the micro-nano magnetic composite liquid 2-6. The friction between the composite liquid 2-6 and the friction force between the micro-nano magnetic composite liquid 2-6 and the stator 3 are controlled, so that the mechanical energy of vibration is converted into heat energy, and the damping effect with adjustable damping is realized.

To sum up, the nonlinear-magnetorheological self-tuning vibration absorber device of this embodiment includes an acceleration sensor, an electronic control unit, a driving module and a vibration absorber. The semi-active vibration control logic of this embodiment includes: a diagnosis step of judging the error vibration level according to the vibration signal of the hydraulic pump; and a control step of receiving the judgment signal of the diagnosis step, and issuing an instruction to act on the vibration absorber, so that The vibration absorber generates electromagnetic driving force to control the magnetic viscosity effect of the micro-nano magnetic composite liquid, and realize semi-active vibration control with controllable damping.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (8)

1. A nonlinear-magnetorheological self-tuning vibration absorber is characterized in that: the vibration control system comprises an acceleration sensor, an electronic control unit, a driving module and a vibration absorber, wherein the acceleration sensor senses the vibration acceleration of the hydraulic pump and transmits the vibration acceleration to the electronic control unit as a vibration signal of closed-loop control; the electronic control unit is used for comparing a vibration signal provided by the acceleration sensor with a preset amplitude value according to the rotating speed value of the motor to obtain an error signal, and generating and outputting a control signal; the driving module outputs a driving signal with certain amplitude and frequency according to the received control signal; the vibration absorber is arranged on the front end cover of the hydraulic pump and used for receiving alternating current with certain amplitude and frequency output by the driving module and acting on the vibration absorber as a driving signal to generate an electromagnetic damping effect so as to achieve the aim of active vibration control; the vibration absorber comprises a dynamic mass, a stator, a guide component and a shell, wherein the stator is of a hollow structure and is sleeved outside the dynamic mass;

the working principle of the vibration absorber is based on the second suspension characteristic of magnetic liquid, the moving mass is suspended in the micro-nano magnetic composite liquid, the non-linear rigidity is generated by axial and radial suspension forces generated by the magnetic liquid under the action of a non-uniform magnetic field, when the external excitation induces the starting mass to move relatively along the guide assembly, unidirectional targeted energy transfer is generated, then the absorbed energy causes the magnetic liquid in the vibration absorber to be extruded, meanwhile, an electromagnetic field distributed on the stator generates a shearing action on a flowing gap of the magnetic liquid, the magnetic liquid generates a magneto-rheological effect under two working modes, and a damping force opposite to the excitation direction is formed, so that the energy consumption effect is achieved.

2. The nonlinear-magnetorheological self-tuned absorber according to claim 1, wherein: the acceleration sensor is arranged on the hydraulic pump shell and used for sensing the vibration signal of the hydraulic pump and transmitting the vibration signal to the electronic control unit as a feedback signal.

3. The nonlinear-magnetorheological self-tuned absorber according to claim 1, wherein: the generating of the control signal specifically includes:

determining the primary order frequency of the motor vibration according to the obtained motor rotating speed value;

carrying out band-pass filtering on the received vibration signal according to the primary order frequency, and reserving the vibration signal frequency component near the vibration primary order;

and judging the vibration of the received primary frequency component, namely when the vibration of the filtered vibration signal near the primary frequency exceeds a preset amplitude value, starting the semi-active control device to work and generating the control signal.

4. The nonlinear-magnetorheological self-tuned absorber according to claim 1, wherein: the driving module is used for receiving the control signal output by the electronic control unit, applying a certain gain to the control signal and generating an alternating current with a certain amplitude and frequency as a driving signal to act on the vibration absorber.

5. The nonlinear-magnetorheological self-tuned absorber according to claim 1, wherein: the dynamic mass comprises an upper end nut, a permanent magnet ring, a magnetic conduction block, a permanent magnet ring retainer, a lower end nut and micro-nano magnetic composite liquid; the upper end nut and the lower end nut are mainly used for connecting the permanent magnet ring and the magnetic conduction block so as to fix the permanent magnet ring on the permanent magnet ring holder; the permanent magnet ring retainer is made of magnetic conductive materials, the inner hole of the permanent magnet ring retainer and the guide shaft form static pressure support, magnetic particle components in the micro-nano magnetic composite liquid material form a rolling friction effect between the inner hole of the permanent magnet ring retainer and the guide shaft, so that the friction force of a contact surface is reduced, and the sensitivity of the dynamic quality to vibration absorption is improved.

6. The nonlinear-magnetorheological self-tuned absorber according to claim 1, wherein: the stator comprises a coil retainer, a coil winding, a copper coil and a coil winding groove; the coil winding is composed of a copper coil and a coil retainer; the coil retainer is of a waist drum-shaped structure, and a coil winding groove is processed on the surface of the coil retainer; the coil winding slots are distributed and arranged from top to bottom by the waist drum-shaped coil retainer from sparse to dense to form electromagnetic field gradient distribution; the coil winding is placed in the coil winding groove; the stator is connected with the shell through bolts.

7. The nonlinear-magnetorheological self-tuned absorber according to claim 1, wherein: the shell comprises an upper end cover, a coil lead inlet, a cylindrical shell, a heat dissipation hole, a lower end cover, a coil lead outlet and a sealing ring; the upper end cover and the lower end cover are sealed by sealing rings, so that the micro-nano magnetic composite liquid is prevented from leaking; radiating holes are uniformly distributed around the cylindrical shell to realize uniform dispersion of vibration heat energy.

8. The nonlinear-magnetorheological self-tuned absorber according to claim 1, wherein: the guide assembly comprises an upper limit block, a guide shaft, a lower limit block and a lubricating groove; the guide shaft penetrates through the permanent magnet ring retainer to form a sliding pair; two ends of the guide shaft are connected with the upper limiting block, the lower limiting block and the shell by threads; the guide shaft is made of non-magnetic-conductive materials and is made of stainless steel.

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