CN202381623U - Precision active damper - Google Patents

Abstract

The utility model provides a precision active damper with a compact structure, belonging to the field of ultra-precision damping. The damper is characterized in that a negative stiffness mechanism and an air spring are connected in parallel to form a passive damping unit; a Lorentz linear actuator forms an active damping unit; and the negative stiffness mechanism is a compression bar structure formed by flat springs, hinges, stiff bars and the like. The damper has the following technical characteristics: the negative stiffness mechanism is installed inside a chamber of the air spring, thus the structure of the damper is more compact; the damper has extremely low stiffness while having high bearing capacity through parallel connection of the positive and negative stiffness mechanisms, thus the natural frequency of the damper is greatly reduced; and the Lorentz linear actuator is used for providing active damping to realize active control. The damper provided by the utility model has extremely low natural frequency, not only has good vibration isolation effect on high frequency vibration interferences but also can effectively isolate ultralow frequency vibration and is suitable for ultra-precision machining and measuring equipment sensitive to vibration.

Description

A kind of accurate active damping device

Technical field

The utility model belongs to ultraprecise vibration damping field, is specifically related to a kind of accurate active damping device.The related accurate active damping device of the utility model has extremely low natural frequency, not only dither is disturbed to have good vibration isolating effect, can also the effective isolation superlow frequency vibrating, be applicable to ultraprecise processing and the measuring equipment responsive to low-frequency vibration.

Background technique

Along with development of science and technology, be that the ultraprecise processing of representative has obtained application more and more widely with measuring equipment with lithography machine, PSTM (STM), scanning type probe microscope (SPM), atom force microscope (AFM) etc.Because its ultraprecise property, this type processing and measuring equipment are also strict further to the requirement of environment micro breadth oscillation.The accurate active damping platform of ultralow frequency can effectively be isolated the low frequency micro breadth oscillation of ground and environment, for equipment provides working environment stably.

Common vibration damper generally adopts the vibration of element separation grounds such as helical steel springs, pneumatic spring.Helical steel springs can't satisfy big bearing capacity and the requirement that suppresses low-frequency vibration simultaneously.Though the ability that pneumatic spring has big bearing capacity and suppresses low-frequency vibration just must adopt methods such as strengthening gas chamber volume if want to realize superlow frequency vibration isolating, can bring the increase of vibration damper volume and the difficulty in the control like this.Therefore, the natural frequency of general pneumatic spring vibration damper about 1.5Hz-2Hz, can't realize the superlow frequency vibration isolating below the 1Hz usually.

American documentation literature US5844664 provides a kind of active damping device, its vertical and level to low rigidity respectively through pneumatic spring and the realization of beat mechanism.Vertical pneumatic spring adopts diaphragm typeair spring, because the requirement in the restriction of vibration damper volume and the control can't realize superlow frequency vibration isolating.

The patent documentation WO95/20113 that world organization's property right tissue is published provides a kind of passive vibration damper of ultralow frequency of positive negative stiffness parallel connection; Its vertical positive rigidity is provided by steel spring; Vertical negative stiffness mechanism is a kind of mechanism that utilizes the depression bar principle to form, and its pretightening force can be passed through screw adjusted.In order to support the load of variation, the position of adopting screw adjusted mechanism to regulate vertical support spring makes vertical negative stiffness mechanism always work near the equilibrium position.

Summary of the invention

The purpose of the utility model is to provide a kind of accurate active damping device; This damping device structure is compact; Has extremely low natural frequency; Not only dither is disturbed to have good vibration isolating effect, can also isolate the superlow frequency vibrating of ground and environment effectively, for ultraprecise processing provides working environment stably with measuring equipment.

A kind of accurate active damping device that the utility model provides is characterized in that this vibration damping equipment comprises active damping unit and passive damper unit, and the active damping unit is parallelly connected with passive damper unit; The active damping unit comprises the Lorentz linear actuator, and passive damper unit is composed in parallel by negative stiffness mechanism and pneumatic spring, and negative stiffness mechanism is installed in the chamber interior of pneumatic spring;

Pneumatic spring comprises metal chamber, rubber film, metal trim ring, fitting seat, load bearing plate, limit stoper, upper piston plate, lower piston plate and inlet hole; The metal chamber is the columnar structured of a kind of inner hollow and open upper end, and upper piston plate and lower piston plate are positioned at the wire chamber chamber interior, through rubber film and the metal chamber is flexible links to each other; Rubber film is structure ringwise, and the rubber film inner ring is placed between upper piston plate and the lower piston plate, and lock sealing, forms the piston structure of pneumatic spring; The metal trim ring is pressed in the outer ring of rubber film on the metal chamber, loads onto above behind the fitting seat metal trim ring and rubber film compressed to be connected on the metal chamber; Limit stoper is installed on the fitting seat, and load bearing plate and upper piston plate are connected, and are used to support damper load; Inlet hole is used for being communicated with air supply system;

Negative stiffness mechanism comprises vertical support piston bar, first, second depression bar, first, second flat spring, first, second clamp, the 3rd, the 4th clamp, first, second adjustment piece, first, second adjusts guide rod, buttress brace and base plate;

Base plate is fixedly mounted on the bottom of metal chamber; Vertical support piston bar and lower piston plate are connected; Vertical support piston bar is connected with an end of first depression bar and second depression bar through hinge; The other end of first depression bar is connected with first clamp through hinge, and the other end of second depression bar is connected with second clamp through hinge; First flat spring passes the first adjustment piece, and the two ends of first flat spring clamp through first clamp and the 3rd clamp respectively; First flat spring passes the second adjustment piece, and the two ends of second flat spring clamp through second clamp and the 4th clamp respectively; Clamp and base plate are connected, and then the fixed plate spring, and the adjustment guide rod passes the first adjustment piece; Its bottom is fixedly connected with base plate; The adjustment guide rod passes the adjustment piece, and its bottom is fixedly connected with base plate, and the top of first, second adjustment guide rod all is fixedly connected with buttress brace; The adjustment piece is fixed on the adjustment guide rod;

The active damping unit is involving vibrations velocity transducer and eddy current displacement sensor also; The Lorentz linear actuator comprises Lorentz linear actuator mover and stator; Mover and load bearing plate are connected, and stator is installed on the fitting seat; Vibrating speed sensors and eddy current displacement sensor are used for the control of vibration damper vibrational feedback, and vibrating speed sensors is installed on the load bearing plate; Eddy current displacement sensor is installed on the fitting seat.

The negative stiffness mechanism that the utility model vibration damper is comprised, its negative stiffness adjustable size, the positive rigidity that is used to mate pneumatic spring, thereby the rigidity size of adjustment vibration damper.The adjustment of negative stiffness realizes through effective bending length of adjusting strip spring; In addition, can also adopt two or multi-disc flat spring parallel connection stack to adjust the rigidity of negative stiffness mechanism.

Passive damping part and active actuator Lorentz linear actuator that the accurate active damping device that the utility model provides is made up of negative stiffness mechanism, pneumatic spring compose in parallel; When isolating dither; Can also effectively isolate vertical superlow frequency vibrating; Overcome general vibration damper and can't realize the shortcoming of superlow frequency vibration isolating, be applicable to ultraprecise processing and the measuring equipment responsive low-frequency vibration.Particularly, the utlity model has following technical characterstic:

(1) adopts the parallelly connected mode of positive negative stiffness, make vibration damper have extremely low natural frequency, not only dither is disturbed to have good vibration isolating effect, can also effectively isolate superlow frequency vibrating;

(2) adopt the initiatively actuator mode parallelly connected with passive damping part, the damping that can increase vibration damper effectively realizes good vibration transmissibility near natural frequency;

(3) initiatively actuator adopts the Lorentz linear actuator, can not only realize active damping, and can encourage vibration insulating system as vibration exciter, and then vibration insulating system is carried out parameter identification;

(4) negative stiffness mechanism is installed in the chamber interior of pneumatic spring, and structure is compact more;

(5) flat spring of can regulate bending length comes the flexural rigidity of adjusting strip spring, under the constant situation of amount of deformation and then can adjust the vertical negative stiffness of negative stiffness mechanism.

Description of drawings

Fig. 1 provides the structural representation of accurate active damping device for the utility model;

Fig. 2 is the structural representation of the utility model negative stiffness mechanism;

Fig. 3 is the schematic diagram of the positive negative stiffness parallel connection of vibration damper that the utility model provides;

Fig. 4 is the schematic diagram of the utility model negative stiffness mechanism;

Fig. 5 is the stiffness curve of the utility model negative stiffness mechanism.

Embodiment

Below in conjunction with Figure of description the structure and the working principle of the utility model specific embodiment are done further detailed explanation.

As shown in Figure 1, the accurate active damping device that the utility model provided comprises the passive damper unit and the active damping unit of positive negative stiffness parallel connection, and passive damper unit and active damping unit are connected in parallel.

Passive damper unit is composed in parallel by positive rigidity pneumatic spring and negative stiffness mechanism.Positive rigidity pneumatic spring comprises metal chamber 1, rubber film 2, metal trim ring 3, fitting seat 4, load bearing plate 5, limit stoper 6, upper piston plate 8, lower piston plate 9 and inlet hole 14.Metal chamber 1 is the columnar structured of a kind of inner hollow and open upper end, during use, with linking to each other with ground through screw around the base plate.Upper piston plate 8 is positioned at metal chamber 1 inside with lower piston plate 9, through rubber film 2 and 1 flexible linking to each other of metal chamber.Rubber film 2 is structure ringwise, and rubber film 2 inner rings are placed between upper piston plate 8 and the lower piston plate 9, and with screw 10 lock sealings that week distributes, forms the piston structure of pneumatic spring.Metal trim ring 3 is pressed in the outer ring of rubber film 2 on the metal chamber 1, loads onto fitting seat 4 back metal trim ring 3 and rubber film 2 being compressed through the screw that distributes in week above and is connected on the metal chamber 1.Fitting seat 4 plays auxiliary installation effect, is used to install limit stoper 6, Lorentz linear actuator stator 12 and eddy current displacement sensor 13.Limit stoper 6 is used for the safety protection effect, and the vertical vibration amplitude of restriction damper load can also play the locking vibration damper in transportation process, prevent the effect of load bearing plate 5 up-down vibration.Load bearing plate 5 and upper piston plate 8 are connected through screw, are used to support damper load.Inlet hole 14 is communicated with air supply system, and the pressurized air that air supply system produces gets into the pneumatic spring chamber through inlet hole 14, floats load.

Negative stiffness mechanism is a kind of depression bar negative stiffness structure, is placed in the chamber interior of pneumatic spring.As depicted in figs. 1 and 2; Negative stiffness mechanism is a kind of symmetrical depression bar structure, and it comprises vertical support piston bar 15, first, second depression bar 16a and 16b, first, second flat spring 18a and 18b, first, second clamp 19a and 19b, the 3rd, the 4th clamp 17a and 17b, first, second adjustment piece 20a and 20b, first, second adjustment guide rod 21a and 21b, buttress brace 22 and base plate 23.

Base plate 23 is fixedly mounted on the bottom of metal chamber 1.The installation of negative stiffness mechanism must guarantee that the shaft axis of vertical support piston bar 15 overlaps with the shaft axis of wire chamber locular wall 1.Vertical support piston bar 15 and lower piston plate 9 are connected through screw.Vertical support piston bar 15 is connected with the end of depression bar 16a, 16b through hinge, and the other end of depression bar 16a is connected with clamp 17a through hinge, and the other end of depression bar 16b is connected with clamp 17b through hinge.Flat spring 18a passes the first adjustment piece 20a, and the two ends of flat spring 18a clamp through clamp 19a and clamp 17a respectively; Flat spring 18b passes the second adjustment piece 20b, and the two ends of flat spring 18b clamp through clamp 19b and clamp 17b respectively.Clamp 19a, 19b and base plate 23 are connected, and then fixed plate spring 18a, 18b.Adjustment guide rod 21a passes the first adjustment piece 20a, and its bottom is fixedly connected with base plate 23, and adjustment guide rod 21b passes adjustment piece 20b, and its bottom is fixedly connected with base plate 23, and the top of adjustment guide rod 21a and 21b all is fixedly connected with buttress brace 22.The structure of being made up of adjustment piece 20a, 20b and adjustment guide rod 21a, 21b is used for the flexural rigidity of adjusting strip spring 18a, 18b, thereby the vertical negative stiffness of adjusting negative stiffness mechanism is used for mating with the rigidity of positive rigidity pneumatic spring.Its principle is to regulate its flexural rigidity through effective bending length of adjusting strip spring 18a, 18b.In addition, can adopt two or the parallel connection of multi-disc flat spring to be superimposed and be used to increase flexural rigidity.Adjustment piece 20a, 20b are fixed on through Cock screw and adjust guide rod 21a, 21b is last.Buttress brace 22 helps out, and is used to strengthen the flexural rigidity of adjustment guide rod 21a, 21b.

The active damping unit comprises Lorentz linear actuator, vibrating speed sensors 7 and eddy current displacement sensor 13.The Lorentz linear actuator comprises Lorentz linear actuator mover 11 and stator 12.Mover 11 is connected with load bearing plate 5, and stator 12 is installed on the fitting seat 4.Mover 11 is permanent magnets, and stator 12 is coils.Vibrating speed sensors 7 is used for the control of vibration damper vibrational feedback with eddy current displacement sensor 13; Vibrating speed sensors 7 is installed on the load bearing plate 5; Feed back to the load absolute velocity; Make the Lorentz linear actuator apply active force through feedback control algorithm, be used for Active Vibration Control load.Eddy current displacement sensor 13 is installed on the fitting seat 4.Eddy current displacement sensor 13 can also be used for the positioning control of load except as vibrational feedback control.

Fig. 3 is the schematic diagram of the positive negative stiffness parallel connection of the utility model vibration damper.Vertical positive stiffness K _aProvide by pneumatic spring; Depression bar 16a, 16b receive flat spring 18a, 18b in the equilibrium position preload pressure effect meeting plays pendulum; Act on the center hinge place when making that the center hinge place with respect to the equilibrium position skew takes place as external disturbance; The preload pressure that depression bar 16a, 16b receive can impel the side-play amount at center hinge place to strengthen, thereby forms vertical negative stiffness.

Fig. 4 has shown the principle that the depression bar negative stiffness forms.The flexural rigidity of flat spring 18a, 18b is K _w, depression bar 16a, 16b length are L, the flat spring 18a of place, equilibrium position, 18b initial bending amount of deformation are δ during no external disturbance.When external disturbance was arranged, the center hinge place can need external force F this moment at vertical skew x _nMake its balance.F _nRepresentation is suc as formula shown in (1):

$F_n=-2K_w[\mathrm{\δ}-(L-\sqrt{L^2-x^2})]\·\frac{x}{\sqrt{L^2-x^2}}---\left(1\right)$

Stiffness K that this mechanism forms then _nRepresentation is:

$K_n=\frac{{\mathrm{dF}}_n}{\mathrm{dx}}={2K}_w[-1+(L-\mathrm{\δ})\frac{L^2}{{(L^2-x^2)}^{3/2}}]---\left(2\right)$

The stiffness curve that Fig. 5 is done according to formula (2) for the utility model negative stiffness mechanism, wherein given flat spring 18a, 18b initial deformation amount δ are 10mm, depression bar 16a, 16b length L are 50mm.Abscissa is represented the side-play amount x of center hinge place with respect to the equilibrium position among Fig. 5, and y coordinate representes that this pressure lever mechanism stiffness coefficient (is K _n/ 2K _w).As can beappreciated from fig. 5, the side-play amount x when center hinge place surpasses a certain value x ₀The time, this mechanism's rigidity can become on the occasion of.Make formula (2) equal zero and to try to achieve x ₀Representation is:

$x_0=\±\sqrt{L^2-{\left[L^2(1-\mathrm{\δ}3\right]}^{2/3}}---\left(3\right)$

In order to guarantee that pressure lever mechanism forms negative stiffness, need loaded work piece near the equilibrium position.In ultra-precise vibration absorber, the vibration amplitude of load is usually in micron level, therefore have x＜＜L, can be expressed as according to formula (2) pressure lever mechanism rigidity this moment:

$K_n=-{2K}_w\·\frac{\mathrm{\δ}}{L}---\left(4\right)$

After vibration damper floated load, the vertical position of adjustment damper load made negative stiffness mechanism be in equilibrium position shown in Fig. 3 perhaps near it.Under the load micro breadth oscillation, this negative stiffness mechanism rigidity can be provided by formula (4).

The above is the preferred embodiment of the utility model, but the utility model should not be confined to the disclosed content of this embodiment and accompanying drawing.So, everyly do not break away from the equivalence of accomplishing under the spirit disclosed in the utility model or revise, all fall into the scope of the utility model protection.

Claims (1)

1. an accurate active damping device is characterized in that, this vibration damping equipment comprises active damping unit and passive damper unit, and the active damping unit is parallelly connected with passive damper unit; The active damping unit comprises the Lorentz linear actuator, and passive damper unit is composed in parallel by negative stiffness mechanism and pneumatic spring, and negative stiffness mechanism is installed in the chamber interior of pneumatic spring;

Pneumatic spring comprises metal chamber, rubber film, metal trim ring, fitting seat, load bearing plate, limit stoper, upper piston plate, lower piston plate and inlet hole; The metal chamber is the columnar structured of a kind of inner hollow and open upper end, and upper piston plate and lower piston plate are positioned at the wire chamber chamber interior, through rubber film and the metal chamber is flexible links to each other; Rubber film is structure ringwise, and the rubber film inner ring is placed between upper piston plate and the lower piston plate, and lock sealing, forms the piston structure of pneumatic spring; The metal trim ring is pressed in the outer ring of rubber film on the metal chamber, loads onto above behind the fitting seat metal trim ring and rubber film compressed to be connected on the metal chamber; Limit stoper is installed on the fitting seat, and load bearing plate and upper piston plate are connected, and are used to support damper load; Inlet hole is used for being communicated with air supply system;

Negative stiffness mechanism comprises vertical support piston bar, first, second depression bar, first, second flat spring, first, second clamp, the 3rd, the 4th clamp, first, second adjustment piece, first, second adjusts guide rod, buttress brace and base plate;

Base plate is fixedly mounted on the bottom of metal chamber; Vertical support piston bar and lower piston plate are connected; Vertical support piston bar is connected with an end of first depression bar and second depression bar through hinge; The other end of first depression bar is connected with first clamp through hinge, and the other end of second depression bar is connected with second clamp through hinge; First flat spring passes the first adjustment piece, and the two ends of first flat spring clamp through first clamp and the 3rd clamp respectively; First flat spring passes the second adjustment piece, and the two ends of second flat spring clamp through second clamp and the 4th clamp respectively; Clamp and base plate are connected, and then the fixed plate spring, and the adjustment guide rod passes the first adjustment piece; Its bottom is fixedly connected with base plate; The adjustment guide rod passes the adjustment piece, and its bottom is fixedly connected with base plate, and the top of first, second adjustment guide rod all is fixedly connected with buttress brace; The adjustment piece is fixed on the adjustment guide rod;

The active damping unit is involving vibrations velocity transducer and eddy current displacement sensor also; The Lorentz linear actuator comprises Lorentz linear actuator mover and stator; Mover and load bearing plate are connected, and stator is installed on the fitting seat; Vibrating speed sensors and eddy current displacement sensor are used for the control of vibration damper vibrational feedback, and vibrating speed sensors is installed on the load bearing plate; Eddy current displacement sensor is installed on the fitting seat.

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