CN116146658A - Six-degree-of-freedom vibration isolation platform supported by quasi-zero stiffness support column based on active control - Google Patents

Abstract

The invention belongs to the technical field of engineering vibration reduction, and particularly relates to a six-degree-of-freedom vibration isolation platform supported by a quasi-zero stiffness support based on active control. The vibration isolation system not only fully utilizes the advantages of the quasi-zero stiffness technology and active control, so that the vibration isolation system has excellent vibration isolation effect on the whole frequency band, but also can make the external excitation of the vibration isolation object be multidirectional.

Description

Six-degree-of-freedom vibration isolation platform supported by quasi-zero stiffness support column based on active control

Technical Field

The invention relates to the technical field of engineering vibration reduction, in particular to a six-degree-of-freedom vibration isolation platform supported by a quasi-zero stiffness support column based on active control.

Background

Along with the rapid development of science and technology, various industries have higher requirements on vibration isolation, such as ships, railways, spacecrafts, precise instruments and the like, the normal operation of equipment is directly affected by the generation of vibration, but the equipment is often subjected to external excitation and vibration generated by the equipment in the operation process, and researches show that an effective vibration elimination and isolation means has a vital effect on the engineering field. In general, vibration isolation initiation frequency and transmissibility are two important parameters for evaluating vibration isolation performance, and a vibration isolation system with excellent performance should have a lower vibration isolation initiation frequency and a lower transmissibility to obtain a wider vibration isolation band and reduce the damage of vibration. The parameters affecting the main performance of the vibration isolation system are natural frequency and damping ratio. If a vibration isolation system with smaller rigidity is selected, the natural frequency of the vibration isolation system is reduced, so that the vibration isolation initial frequency is reduced, the vibration isolation frequency band is widened, but the bearing capacity of the vibration isolation system is reduced, and the static displacement is increased; if the system damping is increased, the vibration transmissibility of the vibration isolation system at the resonance frequency point is reduced, but the vibration transmissibility at high frequencies is increased. Based on the situation, a great deal of research is made on quasi-zero stiffness, wherein the quasi-zero stiffness has high static and low dynamic stiffness characteristics, namely, the quasi-zero stiffness has higher stiffness under static working conditions to ensure the bearing capacity of the quasi-zero stiffness, and has lower stiffness under high frequency conditions to reduce the vibration transmissivity and has a critical influence on low-frequency vibration isolation; nevertheless, most quasi-zero stiffness isolators are developed for vibration isolation in the vertical translational direction, whereas in practice, external excitations tend to be from multiple directions.

Disclosure of Invention

The invention aims to solve the technical problems that: a problem of how to reduce vibrations transmitted from multiple directions.

The invention provides a six-degree-of-freedom vibration isolation platform supported by a quasi-zero stiffness support based on active control, which comprises a platform bottom plate, a bearing platform and at least two vibration reduction mechanism groups, wherein all the vibration reduction mechanism groups are uniformly distributed on the platform bottom plate and jointly support the bearing platform;

each vibration reduction mechanism group comprises two vibration reduction mechanisms, and the two vibration reduction mechanisms are obliquely arranged with each other;

each vibration reduction mechanism comprises a motor mounting seat, a quasi-zero stiffness device and a connecting rod, wherein the motor mounting seats are fixedly arranged on a platform bottom plate, the lower ends of the quasi-zero stiffness devices are fixedly connected with the motor mounting seats, the upper ends of the quasi-zero stiffness devices are fixedly connected with the lower ends of the connecting rods, the upper ends of the connecting rods are provided with connecting pieces fixedly connected with the connecting pieces, and the connecting pieces are fixedly connected with a bearing platform;

the connecting rod comprises at least two sections of rod bodies, and the end parts of the two adjacent rod bodies are connected together through a flexible hinge.

Further, the axes of the motor mounting seat, the quasi-zero stiffness device and the connecting rod are collinear in a stable equilibrium state.

Further, the included angles among the axes of the motor mounting seat, the quasi-zero stiffness device and the connecting rod and the platform bottom plate are all 45 degrees.

Further, the upper ends of two connecting rods in each vibration reduction mechanism group are connected with the bearing platform through the same connecting piece, one surface of each connecting rod connected with the connecting piece is obliquely arranged, and the axis of each connecting rod is perpendicular to the side surface of the connecting piece connected with the connecting piece.

Further, the quasi-zero stiffness device comprises an active actuator, a shell, an actuating rod and a fixed block, wherein the active actuator is installed in a motor installation seat, the shell is fixedly connected to the upper end of the active actuator, a through hole is formed in the upper end of the shell, the lower end of the actuating rod is fixedly connected with the output end of the active actuator, the upper end of the actuating rod is fixedly connected with the lower end of a connecting rod, the fixed block is fixedly arranged in the middle of the actuating rod, the fixed block is located in the shell, a first spring is arranged between the upper end of the fixed block and the shell, at least two elastic pieces which are distributed circumferentially and in a contracted state are arranged beside the fixed block, and two ends of each elastic piece are hinged to the shell and the fixed block respectively.

Further, the elastic piece adopts a second spring.

Further, the elastic piece adopts Euler beams.

Further, the active actuator is one of an electromagnetic actuator, a pneumatic actuator and a piezoelectric actuator.

Further, the casing includes upper cover, first shell, second shell and third shell, upper cover, first shell, second shell and third shell fixed connection in proper order, the through-hole sets up on the upper cover, all the elastic component is kept away from the one end of action bars and is all handed over with the second shell, the tip and the initiative actuator fixed connection of third shell.

Further, the connecting rod is connected with the connecting piece through threads.

The invention has the beneficial effects that:

the invention provides the vibration isolation platform with multiple degrees of freedom, which not only fully utilizes the advantages of the quasi-zero stiffness technology and active control to ensure that the vibration isolation system has excellent vibration isolation effect on the whole frequency band, but also ensures that the external excitation to the vibration isolation object can be multidirectional. And changing the thrust of the active actuator in the quasi-zero stiffness of each vibration reduction mechanism under the feedback signals of the displacement, speed and acceleration sensors, and controlling the vibration of the vibration isolation object in real time. The vibration isolation frequency band of the vibration isolation system is improved from the traditional linear vibration isolation theory; from the vibration active control angle, the advantage of the active control technology in a low frequency band is fully utilized, and the low-frequency resonance peak value of the system is restrained.

Drawings

In order to more clearly illustrate the technical solutions of the present invention, the drawings that are needed for the present invention will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is an overall front view of a first embodiment of the present invention;

FIG. 2 is an overall side view of a first embodiment of the invention;

FIG. 3 is a schematic perspective view of a quasi-zero stiffness device according to an embodiment of the present invention;

FIG. 4 is a schematic view of a partial perspective view of a quasi-zero stiffness apparatus according to an embodiment of the present invention;

FIG. 5 is a schematic perspective view of a connecting rod according to an embodiment of the present invention;

fig. 6 is a schematic partial perspective view of a quasi-zero stiffness device when the elastic member is an euler beam in the second embodiment of the present invention.

Reference numerals: 1. a platform floor; 2. a load-bearing platform; 3. a vibration damping mechanism; 31. a motor mounting seat; 32. a quasi-zero stiffness means; 321. an active actuator; 322. a housing; 323. an actuating lever; 324. a fixed block; 325. a first spring; 326. an elastic member; 33. a connecting rod; 34. a connecting piece; 4. a flexible hinge; 5. an upper cover; 6. a first housing; 7. a second housing; 8. and a third housing.

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown.

1-5, a six-degree-of-freedom vibration isolation platform supported by a quasi-zero stiffness support based on active control comprises a platform bottom plate 1, a bearing platform 2 and at least two vibration reduction mechanism groups, wherein all vibration reduction mechanism groups are uniformly distributed on the platform bottom plate 1 and all vibration reduction mechanism groups support the bearing platform 2 together; when the vibration isolation object is placed on the bearing platform 2 in operation, after the vibration isolation object vibrates in operation, vibration is transmitted to the vibration reduction mechanism group along the bearing platform 2, vibration is reduced through the vibration reduction mechanism group, and further transmission of the vibration is avoided or further transmission of the vibration is reduced. In the invention, the number of the vibration reduction mechanism groups can be two or more, firstly, one vibration reduction mechanism group cannot play a good supporting role on the bearing platform 2, secondly, whether more vibration reduction mechanism groups are required to be arranged or not is judged according to actual conditions, if the bearing platform 2 is triangular or approximate to the triangle, the three sides all need to be supported by the vibration reduction mechanism groups, so that the stability of the vibration reduction mechanism groups on the supporting of the bearing platform 2 can be improved, and vibration transmitted in more directions can be absorbed. Similarly, if the carrying platform 2 is of a polygonal structure, and the carrying platform 2 is larger in size, a vibration damping mechanism group may be disposed on each side of the carrying platform 2, so as to provide stable supporting capability and better vibration damping capability.

In order to enable the vibration reduction mechanism groups to reduce vibration of excitation in multiple directions, each vibration reduction mechanism group comprises two vibration reduction mechanisms 3, the two vibration reduction mechanisms 3 are arranged obliquely to each other, vibration reduction can be continuously performed on excitation in the vertical direction after the vibration reduction mechanisms 3 are arranged obliquely, vibration reduction effects can be achieved on excitation in many other directions, in addition, the two vibration reduction mechanisms 3 are arranged obliquely to each other, a triangle can be formed, and better supporting force is provided for the bearing platform 2.

Each vibration reduction mechanism 3 comprises a motor mounting seat 31, a quasi-zero stiffness device 32 and a connecting rod 33, wherein the motor mounting seat 31 is fixedly arranged on the platform bottom plate 1, the lower end of the quasi-zero stiffness device 32 is fixedly connected with the motor mounting seat 31, the upper end of the quasi-zero stiffness device 32 is fixedly connected with the lower end of the connecting rod 33, the upper end of the connecting rod 33 is provided with a connecting piece 34 fixedly connected with the connecting piece 34, and the connecting piece 34 is fixedly connected with the bearing platform 2; the quasi-zero stiffness device 32 has high static stiffness and low dynamic stiffness, can provide stable supporting force for the bearing platform 2 in a stable state, can amplify vibration signals when excited vibration is received, and performs active control to offset the vibration.

In order to avoid that the vibration reduction mechanism 3 forms a triangle to stably support the bearing platform 2 so that the bearing platform 2 cannot vibrate, the connecting rod 33 comprises at least two sections of rod bodies, and the end parts of the two adjacent rod bodies are connected together through the flexible hinge 4, so that the vibration of the bearing platform 2 can be realized.

Specifically, the axes of the motor mounting seat 31, the quasi-zero stiffness device 32 and the connecting rod 33 in a stable balanced state are collinear, so that the transmission direction of vibration is more accurate, and the vibration can be counteracted more conveniently and actively. If the axes of the motor mounting seat 31, the quasi-zero stiffness device 32 and the connecting rod 33 are not arranged in a collinear state, at least the axes are arranged in parallel, otherwise, the transmission direction of vibration is too disordered, and the follow-up operations of active control elimination and the like of the vibration are inconvenient.

In order to make the excitation direction received by each vibration damping structure wider, the angles between the axes of the motor mounting seat 31, the quasi-zero stiffness device 32 and the connecting rod 33 and the platform bottom plate 1 are 45 degrees, if the angles between the axes of the motor mounting seat 31, the quasi-zero stiffness device 32 and the connecting rod 33 and the platform bottom plate 1 are larger than 45 degrees, the transmission of the excitation in the vertical direction in the vibration damping mechanism 3 is facilitated, but the transmission of the excitation in the wider horizontal direction in the vibration damping mechanism 3 is not facilitated, and if the angles between the axes of the motor mounting seat 31, the quasi-zero stiffness device 32 and the connecting rod 33 and the platform bottom plate 1 are smaller than 45 degrees, the transmission of the excitation in the horizontal direction in the vibration damping mechanism 3 is facilitated, but the transmission of the excitation in the vertical direction in the vibration damping mechanism 3 is not facilitated, so that the angles between the axes of the motor mounting seat 31, the quasi-zero stiffness device 32 and the connecting rod 33 and the platform bottom plate 1 are optimally arranged, and the excitation in all directions can be balanced for transmission in the vibration damping mechanism 3.

Specifically, the upper ends of the two connecting rods 33 in each vibration reduction mechanism group are connected with the bearing platform 2 through the same connecting piece 34, one surface of the connecting piece 34 connected with each connecting rod 33 is obliquely arranged, and the axis of the connecting rod 33 is perpendicular to the side surface of the connecting piece 34 connected with the connecting rod. When vibration is generated by the vibration isolation object, the vibration can be transmitted to the vibration reduction mechanism 3 better by the above arrangement.

Specifically, the quasi-zero stiffness device 32 includes an active actuator 321, a housing 322, an actuating rod 323 and a fixing block 324, the active actuator 321 is installed in the motor installation seat 31, the housing 322 is fixedly connected at the upper end of the active actuator 321, a through hole is formed at the upper end of the housing 322, the lower end of the actuating rod 323 is fixedly connected with the output end of the active actuator 321, the upper end of the actuating rod 323 is fixedly connected with the lower end of the connecting rod 33, the fixing block 324 is fixedly arranged in the middle of the actuating rod 323 and the fixing block 324 is located in the housing 322, a first spring 325 is arranged between the upper end of the fixing block 324 and the housing 322, at least two elastic pieces 326 which are circumferentially distributed and in a contracted state are arranged beside the fixing block 324, and two ends of each elastic piece 326 are respectively hinged with the housing 322 and the fixing block 324.

Working principle: the vibration isolation device comprises a vibration isolation object, a bearing platform 2, a displacement sensor, a speed sensor and an acceleration sensor, wherein the displacement sensor, the speed sensor and the acceleration sensor are arranged on the vibration isolation object and are fixed on the bearing platform 2, the vibration isolation object is controlled by a controller, the structure of the controller and the control of the controller on the displacement sensor, the speed sensor and the acceleration sensor are all the prior art, details are omitted, the rigidity of an elastic piece 326 and a first spring 325 in the quasi-zero rigidity device 32 is designed and adjusted according to the mass of the vibration isolation object, so that the vibration isolation object can be kept in a quasi-zero rigidity state after the vibration isolation object is arranged on the bearing platform 2, when the vibration isolation object vibrates or is subjected to external excitation vibration, the vibration is transmitted to the quasi-zero rigidity device 32 through each connecting rod 33, so that the fixed block 324 is driven to vibrate together by pushing the movable rod 323, the balance of the elastic force direction of the elastic piece 326 perpendicular to the axis of the movable rod 323 is broken, the movable rod 323 and the fixed block 324 can be pushed together, the traditional vibration isolation system with linear rigidity can play a vibration isolation effect only when the external excitation frequency is higher, three vibration isolation devices with initial conditions are compressed in the quasi-zero rigidity when the vibration isolation device is subjected to the quasi-zero rigidity, the vibration isolation device is enabled to have a low initial rigidity when the vibration isolation device is subjected to the external excitation frequency, and the vibration isolation device is enabled to have a low excitation effect when the vibration isolation effect is lower when the vibration excitation frequency is lower than the vibration device is started; meanwhile, the displacement sensor, the speed sensor and the acceleration sensor detect the vibration state and transmit signals to the controller, and the controller controls the active actuator 321 to provide power to actively counteract the vibration, so that the vibration reduction effect is achieved.

Specifically, the elastic member 326 employs a second spring. The second spring in the contracted state can provide elastic force to perform the function of the elastic member 326.

Specifically, the active actuator 321 employs one of an electromagnetic actuator, a pneumatic actuator, and a piezoelectric actuator. The active actuators 321 are each controllable by the controller to provide a corresponding force to counteract the vibrations.

Specifically, the casing 322 includes an upper cover 5, a first casing 6, a second casing 7, and a third casing 8, where the upper cover 5, the first casing 6, the second casing 7, and the third casing 8 are sequentially and fixedly connected, a through hole is formed in the upper cover 5, one end of all elastic members 326, which is far away from the actuating rod 323, is connected with the second casing 7, and an end of the third casing 8 is fixedly connected with the active actuator 321; the assembled structure of the housing 322 can realize quick installation, and is also convenient for adjusting the rigidity of the structures such as the fixed block 324, the second spring and the like in the housing 322.

Specifically, the connecting rod 33 is connected with the connecting piece 34 through threads, and the threaded connection is quick and convenient.

In the second embodiment, as shown in fig. 6, the only difference between the second embodiment and the first embodiment is that the elastic member 326 adopts an euler beam, which is a common elastic structure and can also be used to provide elastic force to realize the action of the elastic member 326, and the direction of the force provided by the euler beam is stable, such that the situation of bending itself will not occur like the second spring during the working process, but the ductility of the euler beam is not good as the second spring, that is, the moving distance of the fixed block 324 and the actuating rod 323 will be more limited, and the euler beam can be specifically selected according to the practical situation.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (10)

1. Six degrees of freedom vibration isolation platform that quasi-zero rigidity pillar supported based on initiative control, its characterized in that: the device comprises a platform bottom plate (1), a bearing platform (2) and at least two vibration reduction mechanism groups, wherein all the vibration reduction mechanism groups are uniformly distributed on the platform bottom plate (1) and jointly support the bearing platform (2);

each vibration reduction mechanism group comprises two vibration reduction mechanisms (3), and the two vibration reduction mechanisms (3) are obliquely arranged;

each vibration reduction mechanism (3) comprises a motor mounting seat (31), a quasi-zero stiffness device (32) and a connecting rod (33), wherein the motor mounting seats (31) are fixedly arranged on a platform bottom plate (1), the lower ends of the quasi-zero stiffness devices (32) are fixedly connected with the motor mounting seats (31), the upper ends of the quasi-zero stiffness devices (32) are fixedly connected with the lower ends of the connecting rods (33), the upper ends of the connecting rods (33) are provided with connecting pieces (34) fixedly connected with the connecting pieces, and the connecting pieces (34) are fixedly connected with a bearing platform (2);

the connecting rod (33) comprises at least two sections of rod bodies, and the end parts of the two adjacent rod bodies are connected together through a flexible hinge (4).

2. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 1, wherein: the axes of the motor mounting seat (31), the quasi-zero stiffness device (32) and the connecting rod (33) are collinear in a stable equilibrium state.

3. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 1, wherein: the included angles among the axes of the motor mounting seat (31), the quasi-zero stiffness device (32) and the connecting rod (33) and the platform bottom plate (1) are 45 degrees.

4. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 1, wherein: the upper ends of two connecting rods (33) in each vibration reduction mechanism group are connected with the bearing platform (2) through the same connecting piece (34), one surface, connected with each connecting rod (33), of the connecting piece (34) is obliquely arranged, and the axis of each connecting rod (33) is perpendicular to the side surface, connected with the connecting piece (34), of the connecting piece.

5. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 1, wherein: the quasi-zero stiffness device (32) comprises an active actuator (321), a shell (322), an actuating rod (323) and a fixed block (324), wherein the active actuator (321) is installed in a motor installation seat (31), the shell (322) is fixedly connected to the upper end of the active actuator (321), a through hole is formed in the upper end of the shell (322), the lower end of the actuating rod (323) is fixedly connected with the output end of the active actuator (321), the upper end of the actuating rod (323) is fixedly connected with the lower end of a connecting rod (33), the fixed block (324) is fixedly arranged in the middle of the actuating rod (323) and is located in the shell (322), a first spring (325) is arranged between the upper end of the fixed block (324) and the shell (322), at least two elastic pieces (326) which are circumferentially distributed and in a contracted state are arranged on the side of the fixed block (324), and two ends of each elastic piece (326) are respectively hinged with the shell (322) and the fixed block (324).

6. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 5, wherein: the elastic member (326) adopts a second spring.

7. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 5, wherein: the elastic piece (326) adopts an Euler beam.

8. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 5, wherein: the active actuator (321) adopts one of an electromagnetic actuator, a pneumatic actuator and a piezoelectric actuator.

9. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 5, wherein: the casing (322) includes upper cover (5), first shell (6), second shell (7) and third shell (8), upper cover (5), first shell (6), second shell (7) and third shell (8) fixed connection in proper order, the through-hole sets up on upper cover (5), all elastic component (326) keep away from the one end of action bars (323) and all handing-over with second shell (7), the tip and the initiative actuator (321) fixed connection of third shell (8).

10. The six degree of freedom vibration isolation platform supported by actively controlled quasi-zero stiffness struts of claim 1, wherein: the connecting rod (33) is connected with the connecting piece (34) through threads.

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