阅读说明：本技术 一种多自由度隔振系统 (Multi freedom vibration isolation system ) 是由 王俊芳 谢溪凌 林健富 杜彦良 任伟新 周海俊 王保宪 张颖 方泽锋 周锐 马聪 于 2021-08-15 设计创作，主要内容包括：本发明公开了一种多自由度隔振系统,包括支腿机构、载物平台和基础平台,所述支腿机构包括惯容模组和波纹管阻尼模组；所述载物平台和所述基础平台通过6个所述支腿机构连接,所述支腿机构的上端与所述载物平台铰接,所述支腿机构的下端与所述基础平台铰接；所述载物平台上连接有第一质量模组,所述基础平台固定设置于任一平面或连接有第二质量模组。本发明推导了其动力学方程等计算方法,其振动方程包括支腿传递特性以及阻抗矩阵推导,为实现其应用提供保障,同时基于此与现有各六自由度平台实现精确对比,有助于实现更优的减振效果。(The invention discloses a multi-degree-of-freedom vibration isolation system which comprises a supporting leg mechanism, an object carrying platform and a foundation platform, wherein the supporting leg mechanism comprises an inertial volume module and a corrugated pipe damping module; the object carrying platform is connected with the base platform through 6 supporting leg mechanisms, the upper ends of the supporting leg mechanisms are hinged with the object carrying platform, and the lower ends of the supporting leg mechanisms are hinged with the base platform; the loading platform is connected with a first quality module, and the basic platform is fixedly arranged on any plane or connected with a second quality module. The invention deduces calculation methods such as a kinetic equation and the like, and a vibration equation comprises the support leg transmission characteristic and impedance matrix deduction, so that the application of the support leg transmission characteristic and the impedance matrix deduction is guaranteed, and meanwhile, the accurate comparison with the existing six-degree-of-freedom platforms is realized on the basis, and the better vibration reduction effect is realized.)

1. A multi-degree-of-freedom vibration isolation system is characterized by comprising a supporting leg mechanism, an object carrying platform and a base platform, wherein the supporting leg mechanism comprises an inertial volume module and a corrugated pipe damping module; the inerter module comprises a first spring, and the inerter is sleeved with the first spring; the corrugated pipe damping module comprises a corrugated pipe damper, a second spring and a third spring, the third spring is installed at the first end of the corrugated pipe damper, and the second spring is sleeved outside the corrugated pipe damper; the object carrying platform is connected with the base platform through 6 supporting leg mechanisms, the upper ends of the supporting leg mechanisms are hinged with the object carrying platform, and the lower ends of the supporting leg mechanisms are hinged with the base platform; the loading platform is connected with a first quality module, and the basic platform is fixedly arranged on any plane or connected with a second quality module.

2. The vibration isolation system with multiple degrees of freedom according to claim 1, wherein the method for calculating the transfer characteristic of the vibration isolation system with multiple degrees of freedom comprises: modeling by using an elastic substructure method based on a transfer matrix, wherein the elastic substructure comprises the following elastic substructures: the objective platform, landing leg mechanism, basic platform.

3. The multiple degree of freedom vibration isolation system of claim 2, wherein the calculation method comprises: setting H as a transfer matrix, x as a displacement vector, f as a node stress vector, subscript i as an inner point, and subscript c as a connection point; the inner points comprise an outer excitation point and a response point of interest; the object carrying platform is set as P, and the basic platform is set as B;

the transfer characteristic of the carrier platform is expressed as,

the transfer characteristics of the underlying platform are expressed as,

4. the vibration isolation system with multiple degrees of freedom according to claim 3, wherein the frequency response function matrix of the vibration isolation system with multiple degrees of freedom is calculated according to the following formula (1) and formula (2):

5. the vibration isolation system with multiple degrees of freedom according to claim 4, wherein the calculation method of the internal force at the connecting point of the inerter-bellows damping module is as follows: setting the internal force at the connecting point of the supporting leg mechanism and the loading platform as f₁The internal force at the connecting point of the supporting leg and the base platform is set as f₂The equivalent basic mass of the supporting leg mechanism frame is m, the equivalent mass of the inertial container is b, and the first spring is k₁，

6. The vibration isolation system with multiple degrees of freedom according to claim 5, wherein the calculation method of the impedance matrix of the leg mechanism is as follows: let Z' be an anti-impedance matrix,

7. the multiple degrees of freedom vibration isolation system according to claim 6, wherein the multiple degrees of freedom vibration isolation system considers a mounting angle by: setting a rotation matrix R, setting I as a unit matrix, and R ═ R_x r_y r_z]Is a unit rotation vector obtained by cross multiplication of the same vector before and after rotation, theta is an included angle of the two vectors,

8. the vibration isolation system with multiple degrees of freedom according to claim 7, wherein the calculation method for satisfying the displacement coordination condition and the stress balance condition of the substructure where the object carrying platform and the foundation platform are located at the connection point comprises the following steps:

R＝TZ′T^-1 (10)

9. the multiple degree of freedom vibration isolation system according to any one of claims 1 to 8, wherein the vibration transfer function of any one of said leg mechanisms is calculated in a manner that: let the vibration transfer function be T1, the equivalent mass of the inerter be b, the stiffness of the first spring be k1, the damping of the bellows damper be c, the equivalent parallel spring stiffness of the bellows damper be k2, the equivalent series spring stiffness of the bellows damper be k3, x be the displacement vector,

10. the vibration isolation system with multiple degrees of freedom according to any one of claims 1 to 8, wherein 3 upper spherical hinge seats are uniformly distributed on the circumference of the bottom surface of the loading platform, and 6 lower spherical hinge seats are uniformly distributed on the circumference of the surface of the base platform; the upper spherical hinge seat is provided with two upper spherical hinge interfaces, the lower spherical hinge seat is provided with a lower spherical hinge interface, the upper end of the supporting leg mechanism is provided with an upper spherical hinge which is connected with the upper spherical hinge seat, and the lower end of the supporting leg mechanism is provided with a lower spherical hinge which is connected with the lower spherical hinge seat.

Technical Field

The invention relates to the technical field of six-degree-of-freedom platform vibration reduction, in particular to a multi-degree-of-freedom vibration isolation system.

Background

In the prior art, a passive six-degree-of-freedom platform consists of six supporting legs, six universal hinges respectively arranged at the upper part and the lower part, and an upper platform and a lower platform, wherein when the six supporting legs do telescopic motion, the upper platform moves in six degrees of freedom (X, Y, Z, alpha, beta and gamma) in space. When vibration is generated at the lower platform, the vibration is transmitted to the upper platform through the six legs having a vibration damping function.

The supporting leg structure generally adopted by the passive six-degree-of-freedom platform consists of a spring and a traditional hydraulic damper, and the damping performance is weak because the supporting leg structure only uses two elements of the spring and the damper, so that the damping performance of the whole platform is poor. The existing fluid damper is most common as a cylinder type hydraulic damper, and the cylinder type hydraulic damper has sliding fit of a piston and a cylinder barrel and sliding fit of a piston rod and an end cover, and a friction dead zone exists in the fit. When the vibration is small, the friction dead zone enables the originally designed vibration isolation frequency to move upwards, so that the vibration isolation effect is reduced; the micro-vibration isolation of the platform is very unfavorable, and meanwhile, a large error can be caused to the vibration test of a large flexible structure.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a multi-degree-of-freedom vibration isolation system, solves the problems that the existing six-degree-of-freedom platform is weak in vibration damping performance and cannot meet higher use requirements, obviously improves the vibration damping performance compared with the traditional passive six-degree-of-freedom platform, and can give consideration to both the vibration isolation effect of small-amplitude vibration and the dissipation of impact load.

The invention is realized by the following technical measures, comprising a supporting leg mechanism, a carrying platform and a base platform, wherein the supporting leg mechanism comprises an inertial volume module and a corrugated pipe damping module; the inerter module comprises a first spring, and the inerter is sleeved with the first spring; the corrugated pipe damping module comprises a corrugated pipe damper, a second spring and a third spring, the third spring is installed at the first end of the corrugated pipe damper, and the second spring is sleeved outside the corrugated pipe damper; the object carrying platform is connected with the base platform through 6 supporting leg mechanisms, the upper ends of the supporting leg mechanisms are hinged with the object carrying platform, and the lower ends of the supporting leg mechanisms are hinged with the base platform; the loading platform is connected with a first quality module, and the basic platform is fixedly arranged on any plane or connected with a second quality module.

Further, the method for calculating the transfer characteristic of the multi-degree-of-freedom vibration isolation system comprises the following steps: modeling by using an elastic substructure method based on a transfer matrix, wherein the elastic substructure comprises the following elastic substructures: the objective platform, landing leg mechanism, basic platform.

Further, the calculation method comprises the following steps: setting H as a transfer matrix, x as a displacement vector, f as a node stress vector, subscript i as an inner point, and subscript c as a connection point; the inner points comprise an outer excitation point and a response point of interest; the object carrying platform is set as P, and the basic platform is set as B;

the transfer characteristic of the carrier platform is expressed as,

the transfer characteristics of the underlying platform are expressed as,

further, the frequency response function matrix calculation method of the vibration isolation system with multiple degrees of freedom is obtained according to the following formula (1) and formula (2):

further, the method for calculating the internal force at the connecting point of the inerter-bellows damping module comprises the following steps: setting the internal force at the connecting point of the supporting leg mechanism and the loading platform as f1, and setting the internal force at the connecting point of the supporting leg and the basic platform as f₂The equivalent basic mass of the supporting leg mechanism frame is m, the equivalent mass of the inertial container is b, and the first spring is k₁，

Further, the calculation method of the resistance matrix of the leg mechanism comprises the following steps: let Z' be an anti-impedance matrix,

further, the method for considering the installation angle of the multiple-degree-of-freedom vibration isolation system comprises the following steps: setting a rotation matrix R, setting I as a unit matrix，r＝[r_x r_y r_z]Is a unit rotation vector obtained by cross multiplication of the same vector before and after rotation, theta is an included angle of the two vectors,

further, the calculation method for satisfying the displacement coordination condition and the stress balance condition of the substructure where the objective platform and the base platform are located at the connecting point comprises the following steps:

R＝TZ′T^-1 (10)

further, the vibration transfer function of any one of the leg mechanisms is calculated in the following manner: let the vibration transfer function be T1, the inertia container equivalent mass be b, the stiffness of the first spring be k1, the damping of the bellows damper be c, the equivalent parallel spring stiffness be k2, the equivalent series spring stiffness be k3, x be the displacement vector,

as a preferable mode, 3 upper spherical hinge seats are uniformly distributed on the circumference of the bottom surface of the object carrying platform, and 6 lower spherical hinge seats are uniformly distributed on the circumference of the surface of the basic platform; the upper spherical hinge seat is provided with two upper spherical hinge interfaces, the lower spherical hinge seat is provided with a lower spherical hinge interface, the upper end of the supporting leg mechanism is provided with an upper spherical hinge which is connected with the upper spherical hinge seat, and the lower end of the supporting leg mechanism is provided with a lower spherical hinge which is connected with the lower spherical hinge seat.

According to the multi-degree-of-freedom vibration isolation system provided by the invention, when the basic platform is excited by vibration, the vibration is transmitted to the object carrying platform through the 6 supporting leg mechanisms with the vibration reduction function. When the basic platform is impacted greatly, the corrugated pipe damper is not easy to generate plastic deformation like a shock absorber adopting a spring and traditional actuating cylinder type hydraulic damping, the plastic deformation like the traditional actuating cylinder type hydraulic damper can not be generated, the damping effect is achieved through self-allowed large deformation and spring assistance, meanwhile, the acceleration difference between two ends of the inertial container is increased steeply, rapidly-increased inertial force is generated, and the movement of the loading platform is hindered. Therefore, the object platform has smaller vibration and more stable movement; the inertial container-corrugated pipe supporting legs of the auxiliary spring are embedded into different positions of the loading platform and the basic platform of the device to form a vibration damping structure, so that a better vibration damping function is provided; meanwhile, the structure effectively improves the vibration control effect of the device on the basis of ensuring the bearing capacity; meanwhile, the invention deduces calculation methods such as a kinetic equation of the system, and a vibration equation of the system comprises the support leg transmission characteristic and impedance matrix deduction, so that the application of the system is guaranteed, and meanwhile, the system is accurately compared with the existing six-degree-of-freedom platforms, and the system is favorable for realizing a better vibration reduction effect.

Drawings

FIG. 1 is a simplified model diagram of equivalent mechanics of a leg of a conventional passive six-DOF platform;

FIG. 2 is a cross-sectional view of a leg mechanism according to a first embodiment of the present invention;

fig. 3 is a schematic structural view of a multi-degree-of-freedom vibration isolation device according to a second embodiment of the present invention;

FIG. 4 is a simplified model diagram of an equivalent mechanics of the leg mechanism according to a third embodiment of the present invention;

fig. 5 is a schematic diagram of an equivalent mechanical simplified model of a support leg of a six-degree-of-freedom platform including an inertial volume module and a conventional actuator cylinder hydraulic damper.

Number and name in the figure: 1. the device comprises a loading platform 2, a base platform 3, an upper spherical hinge 4, a lower spherical hinge 5, an upper spherical hinge seat 6, a lower spherical hinge seat 7, a supporting leg mechanism 8, an inertial container 9, a first spring 10, a second spring 11, a corrugated pipe damper 12 and a third spring

Detailed Description

The present invention will be described in further detail with reference to the following examples and drawings.

Example one

A mechanical vibration reduction mechanism, refer to fig. 2, comprises an inerter module and a bellows damping module which are coaxially connected in series, wherein the inerter module comprises an inerter 8 and a spring, and the bellows damping module comprises a bellows damper 11 and a spring.

It should be noted that the inerter of this embodiment is a mechanical energy storage element, and its characteristics are: the force exerted at its ends is proportional to its relative acceleration and therefore corresponds to a mass element, so that the circuit synthesis theory can be completely transferred into a mechanical network. The inerter has wide application prospect, and has main functions of vibration absorption, suspension design, replacement mass and the like. Common applications of inertias are various mechanical systems for vibration mitigation, such as improved automotive suspension systems, high performance motorcycle steering compensators, train suspension lateral control, mitigation of liquid sloshing in liquid storage tanks, optical platform vibration suppression, and even aircraft landing gear. The inerter element can also be used effectively for passive vibration control of civil engineering structures, in particular as a vibration isolation device effective in increasing the mass effect in structural dynamics applications.

The corrugated pipe is a tubular elastic sensitive element formed by connecting foldable corrugated sheets along the folding and stretching direction, and can be used as a liquid container at the same time. The bellows damping module has the characteristics of providing both damping and stiffness while allowing for large deformations. The bellows type fluid damping vibration isolator of the embodiment has no matching auxiliary and friction dead zone, thereby having good micro-vibration isolation characteristic. Furthermore, the feature of the bellows that allows large deformations for large impact forces or sudden loads can be programmed to avoid plastic deformation of the spring in the case of spring dampers.

Furthermore, the inerter module in this embodiment includes an inerter 8 and a first spring 9, and the inerter 8 is sleeved with the first spring 9 to play a buffering role.

Further, the bellows damping module in this embodiment includes a bellows damper 11, a second spring 10, and a third spring 12, wherein the bellows damper 11 is pre-filled with a viscous damping fluid before use, and the viscous damping fluid can form a pre-pressure in a cavity of the bellows damper; the first end of the corrugated pipe damper 11 is connected with the inertial volume module, the first end of the corrugated pipe damper 11 is provided with a second spring 10, and the second spring 10 can adjust the rigidity and response speed of the second spring; a third spring 12 is sleeved outside the corrugated pipe damper 11, and the height of the third spring 12 is matched with that of the corrugated pipe damper 11; when the mechanical damping mechanism is compressed and shortened, the corrugated pipe and the third spring 12 outside the corrugated pipe are compressed, the pressure in the cavity is increased to a certain value, and effective buffering is formed. The mechanical vibration reduction mechanism is provided with the inertial container 8 and the corrugated pipe damper 11 which are coaxially connected in series, and the spring is arranged at a specific position for assistance, when the vibration reduction mechanism is subjected to large impact, the corrugated pipe damping module is not easy to generate plastic deformation like the traditional actuating cylinder type hydraulic damper, the corrugated pipe damping module plays a buffering role through large deformation allowed by the corrugated pipe damping module and the spring assistance, and meanwhile, the acceleration difference between two ends of the inertial container is increased steeply, so that rapidly increased inertial force is generated, and the axial compression of the vibration reduction mechanism is hindered; the characteristic that the mass effect of the inerter 8 is increased is combined with the characteristic that the corrugated pipe damper 11 provides rigidity and damping effect and allows large deformation, so that compared with the traditional damper, the damping effect is obviously improved, and meanwhile, the damper is simple and compact in structure, high in space adaptation degree, flexible to use, and low in setting cost and maintenance cost.

Example two

The embodiment provides a multiple-degree-of-freedom vibration isolation device, and referring to fig. 2 and fig. 3, the multiple-degree-of-freedom vibration isolation device includes a supporting leg mechanism 7, an object carrying platform 1 and a base platform 2, and the supporting leg mechanism 7 is applied with the mechanical vibration reduction mechanism of the first embodiment; cargo platform 1 and basic platform 2 are connected through 6 landing leg mechanisms 7, and landing leg mechanism 7's upper end is articulated with cargo platform 1, and landing leg mechanism 7's lower extreme is articulated with basic platform 2.

It should be noted that, in the preferred hinge mode of this embodiment, 3 upper spherical hinge seats 5 are uniformly distributed on the circumference of the bottom surface of the object platform 1, and 6 lower spherical hinge seats 6 adapted to the positions of the upper spherical hinge seats 5 are uniformly distributed on the circumference of the surface of the base platform 2; the upper spherical hinge seat 5 is provided with two upper spherical hinge interfaces, the lower spherical hinge seat 6 is provided with a lower spherical hinge interface, the upper end of the supporting leg mechanism 7 is provided with an upper spherical hinge 3 connected with the upper spherical hinge seat 5, and the lower end of the supporting leg mechanism 7 is provided with a lower spherical hinge 4 connected with the lower spherical hinge seat 6.

It is understood that, in other embodiments, the device may be hinged by other means, such as a hooke joint, specifically, the device includes a first hooke joint and a second hooke joint, the first hooke joint connects the upper end of the leg mechanism 7 and the object carrying platform 1, and the second hooke joint connects the lower end of the leg mechanism 7 and the base platform 2; in other embodiments, the manner of articulation should be determined by the environment in which the device is used.

Furthermore, the arrangement circumference of the upper spherical hinge seat 5 is smaller than that of the lower spherical hinge seat 6, namely the support leg mechanism 7 is obliquely arranged.

It should be noted that, in general, the inerter is used in connection with a ram-type hydraulic damper, which can only isolate axial vibration; the support leg mechanism 7 of the present embodiment combines the inertial container and the bellows, and provides multi-directional vibration reduction by combining a plurality of obliquely arranged support leg mechanisms 7 and the upper and lower platforms by using the characteristics of the bellows.

In the multi-degree-of-freedom vibration isolation device of the embodiment, when the base platform 2 is subjected to vibration excitation, vibration is transmitted to the object carrying platform 1 through the 6 supporting leg mechanisms 7 with the vibration reduction function. When the base platform 2 is subjected to large impact, the corrugated pipe damper 11 is not easy to generate plastic deformation like a shock absorber adopting a spring and traditional actuator cylinder type hydraulic damping, and plays a role in buffering through large deformation allowed by the damper and the assistance of the spring, and meanwhile, the acceleration difference between two ends of the inertial container is increased sharply, so that an inertia force which is increased rapidly is generated, and the movement of the loading platform 1 is blocked. Therefore, the object carrying platform 1 has smaller vibration and more stable movement; the inertial volume-corrugated pipe supporting legs of the auxiliary springs are embedded into the object carrying platform 1 and the basic platform 2 at different positions to form a vibration damping structure, so that a better vibration damping function is provided; simultaneously, this structure effectively promotes the vibration control effect of this device on the basis of guaranteeing bearing capacity.

EXAMPLE III

The embodiment provides a multi-degree-of-freedom vibration isolation system, which is applied to the multi-degree-of-freedom vibration isolation device of the second embodiment, wherein a first mass module is connected to an object carrying platform 1, and a base platform 2 is fixedly arranged on any plane or is connected with a second mass module.

The first mass module and the second mass module are determined according to the application of the vibration isolation device with multiple degrees of freedom, and the embodiment does not limit itself.

The system is based on the assumption that each supporting leg, load and base platform 2 are elastic bodies, the whole platform shown in fig. 3 is divided into three elastic substructures of a carrying platform 1, a supporting leg mechanism and a base platform 2, wherein the substructures of the carrying platform 1 comprise first mass modules.

And performing dynamic modeling on the vibration isolation platform by adopting an elastic substructure comprehensive method based on a transmission matrix.

The substructures of the objective platform 1 (marked as P) and the basic platform 2 (marked as B) are modeled respectively, and the transfer characteristics can be expressed as:

in the formula: h is the transfer matrix, x is the displacement vector, f is the node force vector, subscript i is the inner point (typically the outer excitation point or the interesting response point), and subscript c is the connection point.

According to the formula (1) and the formula (2), a frequency response function matrix of the whole system before the synthesis of the substructures can be obtained:

referring to fig. 4, a simplified mechanical model of the leg supporting mechanism 7, a calculation method of an internal force at a connection point of the inerter module and the bellows damping module is as follows:

wherein f is₁Is the internal force f at the connecting point of the supporting leg and the carrying platform 1₂Is the internal force f at the connecting point of the supporting leg and the base platform 2_mIs the equivalent mass m of the supporting leg mechanism, the inertia container b and the first spring k₁Internal forces at the connection points.

The impedance matrix of the present leg mechanism 7 can be expressed as:

r is a rotation matrix considering the installation angle of the vibration isolation device.

Wherein I is a unit matrix, r ═ r_x r_y r_z]Is a unit rotation vector obtained by cross-multiplying the same vector before and after rotation, and theta is the included angle of the two vectors.

In order to meet the displacement coordination condition and the stress balance condition of the substructures of the object carrying platform 1 and the basic platform 2 at the connecting point, the following steps are carried out:

R＝TZ′T^-1 (10)

as shown in fig. 4, the inerter 8 has an equivalent mass b, and the inerter 8 has a first spring rate k₁The damping of the bellows damper 11 is c, and the equivalent parallel spring stiffness of the bellows damper 11 is k₂The equivalent series spring rate of the bellows damper 11 is k₃Then the vibration transfer function T of the single leg mechanism 7₁Is composed of

Referring to fig. 5, the support leg is composed of an inerter and a conventional actuator cylinder type hydraulic damper, the inerter equivalent mass is still set as b, and the stiffness of an auxiliary spring of the inerter is k₁To transmitThe stiffness of the system actuator cylinder type hydraulic damper is k₂Damping is c, the vibration transfer function T of the single leg₂Comprises the following steps:

referring to a mechanical simplified model of a typical supporting leg in a traditional passive six-degree-of-freedom platform shown in FIG. 1, assuming that the rigidity is k2 and the damping is c, the vibration equation T of the supporting leg is₃Comprises the following steps:

by comparison of T₁、T₂、T₃Knowing the difference in transfer function, T₁The two adjustable parameters are more than the other two adjustable parameters, so that the performance adjustment and optimization of the vibration isolation system are facilitated, and a better vibration damping effect can be realized.

It should be noted that, in this embodiment, the inerter and the first spring 9 are connected in parallel to form an inerter module, and the bellows damper 11 and the second spring 10 are connected in series and then connected in parallel with a third spring 12 to form a bellows damping module; for convenience of modeling calculation, the inertial container module is connected with the carrying platform 1, and the corrugated pipe damping module is connected with the basic platform 2; in other embodiments, the substitution of the two positions is not limited, and the calculation method can still be derived by referring to the above calculation method.

The multi-degree-of-freedom vibration isolation system of the embodiment establishes and deduces calculation methods such as a kinetic equation and the like based on the multi-degree-of-freedom vibration isolation device, the vibration equation comprises supporting leg transmission characteristics and impedance matrix deduction, guarantee is provided for application of the multi-degree-of-freedom vibration isolation system, meanwhile, accurate comparison with the existing six-degree-of-freedom platforms is achieved, and the multi-degree-of-freedom vibration isolation system is beneficial to achieving a better vibration reduction effect.

The multi-degree-of-freedom vibration isolation system of the present invention has been described above for the purpose of facilitating understanding of the present invention, but the embodiments of the present invention are not limited to the above-described embodiments, and any changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit of the present invention are intended to be equivalent replacements within the scope of the present invention.