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, in particular to a six-degree-of-freedom vibration isolation platform supported by quasi-zero-stiffness pillars based on active control, including a platform bottom plate, a bearing platform and at least two vibration-damping mechanism groups, each vibration-damping mechanism group Both include two vibration damping mechanisms, each vibration damping mechanism includes a motor mount, a quasi-zero stiffness device and a connecting rod, the motor mount is fixed on the platform floor, and the lower end of the quasi-zero stiffness device is fixedly connected to the motor mount, The upper end of the quasi-zero stiffness device is fixedly connected to the lower end of the connecting rod, and the upper end of the connecting rod is provided with a connecting piece fixedly connected to it. The connecting rod includes at least two sections of rod bodies, and the ends of two adjacent rod bodies are connected together by flexible hinges . The invention not only makes full use of the quasi-zero stiffness technology and the advantages of active control to make the vibration isolation system have excellent vibration isolation effect in the whole frequency band, but also enables the vibration isolation objects to receive external excitations in multiple directions.

Description

A six-degree-of-freedom vibration isolation platform supported by quasi-zero-stiffness pillars 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 quasi-zero-stiffness pillars based on active control.

Background technique

With the rapid development of science and technology, all walks of life have put forward higher requirements for vibration isolation, such as ships, railways, spacecraft and precision instruments, etc. The generation of vibration will directly affect the normal operation of the equipment, but the equipment in In the process of operation, it is often subject to external excitation and self-generated vibration. Studies have shown that effective vibration reduction and isolation methods play a vital role in the engineering field. Generally speaking, the initial frequency of vibration isolation and transmissibility are two important parameters to evaluate the performance of vibration isolation. A vibration isolation system with excellent performance should have a lower initial frequency of vibration isolation and lower transmissibility to obtain a wider Isolate frequency bands and reduce vibration hazards. The parameters that affect the main performance of the vibration isolation system are the natural frequency and the damping ratio. If a vibration isolation system with a smaller stiffness is selected, its natural frequency will decrease, thereby reducing the initial frequency of vibration isolation and widening the frequency band of vibration isolation, but its bearing capacity will decrease and the static displacement will increase; if the system damping is increased, the vibration isolation system will The vibration transmissibility at the resonant frequency decreases, but the vibration transmissibility increases at high frequencies. Based on this situation, people have done a lot of research on quasi-zero stiffness. Quasi-zero stiffness has high static and low dynamic stiffness characteristics, that is, it has high stiffness under static conditions to ensure its bearing capacity, while under high-frequency conditions Lower stiffness to reduce the vibration transmissibility is crucial for low-frequency vibration isolation; nevertheless, most quasi-zero stiffness isolators were developed for vibration isolation in the vertical translational direction, and in practice, External incentives often come from multiple directions.

Contents of the invention

The technical problem to be solved by the invention is: how to reduce the vibration transmitted from multiple directions.

The invention provides a six-degree-of-freedom vibration-isolation platform supported by quasi-zero-stiffness pillars based on active control, including a platform bottom plate, a bearing platform, and at least two vibration-damping mechanism groups. All vibration-damping mechanism groups are evenly distributed on the platform bottom plate and all vibration-damping The mechanism group jointly supports the bearing platform;

Each of the damping mechanism groups includes two damping mechanisms, and the two damping mechanisms are arranged obliquely to each other;

Each of the damping mechanisms includes a motor mount, a quasi-zero stiffness device and a connecting rod, the motor mount is fixedly arranged on the platform bottom plate, the lower end of the quasi-zero stiffness device is fixedly connected to the motor mount, and the The upper end of the quasi-zero stiffness device is fixedly connected to the lower end of the connecting rod, the upper end of the connecting rod is provided with a connecting piece fixedly connected thereto, and the connecting piece is fixedly connected to the bearing platform;

The connecting rod includes at least two sections of rod bodies, and the ends of two adjacent rod bodies are connected together by flexible hinges.

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

Further, the included angles between the axis of the motor mount, the quasi-zero stiffness device and the connecting rod and the platform bottom plate are all 45 degrees.

Further, the upper ends of the two connecting rods in each of the shock absorbing mechanism groups are connected to the bearing platform through the same connecting piece, the side of the connecting piece connected to each connecting rod is inclined, and the axis of the connecting rod Perpendicular to the side the connector is attached to.

Further, the quasi-zero stiffness device includes an active actuator, a casing, an actuating rod and a fixed block, the active actuator is installed in the motor mounting seat, and the casing is fixedly connected to the upper end of the active actuator , the upper end of the housing is provided with a through hole, the lower end of the actuating rod is fixedly connected to the output end of the active actuator, the upper end of the actuating rod is fixedly connected to the lower end of the connecting rod, and the fixed block is fixedly arranged In the middle of the actuating rod and the fixed block is located in the housing, a first spring is provided between the upper end of the fixed block and the housing, and at least two circumferentially distributed and contracted springs are provided on the side of the fixed block. Elastic parts, the two ends of each elastic part are respectively hinged with the housing and the fixed block.

Further, the elastic member adopts a second spring.

Further, the elastic member adopts an Euler beam.

Further, the active actuator adopts one of electromagnetic actuator, pneumatic actuator and piezoelectric actuator.

Further, the housing includes an upper cover, a first shell, a second shell and a third shell, the upper cover, the first shell, the second shell and the third shell are fixedly connected in sequence, and the through hole is arranged on the upper cover Above, the ends of all the elastic members far away from the actuating rod are in contact with the second casing, and the end of the third casing is fixedly connected with the active actuator.

Further, the connection between the connecting rod and the connecting piece is threaded.

The beneficial effects of the present invention are:

The invention proposes a multi-degree-of-freedom vibration isolation platform, which not only makes full use of the quasi-zero stiffness technology and the advantages of active control to make the vibration isolation system have excellent vibration isolation effects in the entire frequency band, but also makes the vibration isolation objects suffer External stimuli can be multidirectional. Under the feedback signals of the displacement, velocity and acceleration sensors, the thrust of the active actuator within the quasi-zero stiffness on each vibration damping mechanism is changed, and the vibration of the vibration isolation object is controlled in real time. From the perspective of traditional linear vibration isolation theory, the vibration isolation frequency band of the vibration isolation system is improved; from the perspective of active vibration control, the advantages of active control technology in the low frequency band are fully utilized to suppress the low frequency resonance peak of the system.

Description of drawings

In order to illustrate the technical solution of the present invention more clearly, the accompanying drawings used in the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are some implementations of the present invention. For those of ordinary skill in the art, In other words, other drawings can also be obtained from these drawings on the premise of not paying creative work.

Fig. 1 is the overall front view of Embodiment 1 of the present invention;

2 is an overall side view of Embodiment 1 of the present invention;

3 is a schematic diagram of a three-dimensional structure of a quasi-zero stiffness device in Embodiment 1 of the present invention;

4 is a schematic diagram of a partial three-dimensional structure of a quasi-zero stiffness device in Embodiment 1 of the present invention;

5 is a schematic diagram of a three-dimensional structure of a connecting rod in Embodiment 1 of the present invention;

Fig. 6 is a schematic diagram of a partial three-dimensional structure of a quasi-zero-stiffness device in Embodiment 2 of the present invention when the elastic member is an Euler beam.

Reference signs: 1. Platform bottom plate; 2. Bearing platform; 3. Vibration reduction mechanism; 31. Motor mounting base; 32. Quasi-zero stiffness device; 321. Active actuator; 322. Housing; 323. Actuating rod 324, fixed block; 325, first spring; 326, elastic member; 33, connecting rod; 34, connector; 4, flexible hinge; 5, upper cover; 6, first shell; 7, second shell; 8 , the third shell.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are part of the embodiments of the present invention, but not all of them.

Embodiment 1, as shown in Figures 1 to 5, a six-degree-of-freedom vibration-isolation platform supported by quasi-zero-stiffness pillars based on active control includes a platform bottom plate 1, a bearing platform 2 and at least two vibration-damping mechanism groups, and all vibration-damping The mechanism groups are evenly distributed on the platform bottom plate 1 and all the vibration-damping mechanism groups jointly support the bearing platform 2; when working, the vibration isolation object is placed on the bearing platform 2, when the vibration isolation object vibrates during operation, the vibration along the When the bearing platform 2 is transferred to the vibration damping mechanism group, the vibration is damped by the vibration damping mechanism group to avoid further transmission of vibration or reduce further transmission of vibration. The number of damping mechanism groups in the present invention can be two or more. First, one vibration damping mechanism group cannot play a good supporting role on the bearing platform 2. Secondly, whether to set more vibration damping mechanism groups depends on the actual situation. Judging from the situation, if the bearing platform 2 is triangular or approximately triangular, then the three sides need to be supported by the vibration damping mechanism group, which can improve the stability of the vibration damping mechanism group supporting the bearing platform 2, and can also absorb more direction transmission and coming vibration. Similarly, if the carrying platform 2 is a polygonal structure and the carrying platform 2 is large in size, a vibration-damping mechanism group can be provided on each side of the carrying platform 2 to provide stable support and better shock-absorbing capabilities.

In order to enable the vibration damping mechanism group to damp the excitation in multiple directions, each vibration damping mechanism group includes two vibration damping mechanisms 3, and the two vibration damping mechanisms 3 are arranged obliquely to each other. Not only can continue to damp the excitation in the vertical direction, but also can reduce the vibration of the excitation in many other directions. In addition, the two vibration damping mechanisms 3 are arranged obliquely to each other to form a triangle, which is beneficial to the bearing Platform 2 provides better support.

Each damping mechanism 3 all comprises motor mount 31, quasi-zero stiffness device 32 and connecting rod 33, and motor mount 31 is fixedly arranged on the platform base plate 1, and the lower end of quasi-zero stiffness device 32 is fixedly connected with motor mount 31, The upper end of the quasi-zero stiffness device 32 is fixedly connected to the lower end of the connecting rod 33, and the upper end of the connecting rod 33 is provided with a connecting piece 34 fixedly connected thereto, and the connecting piece 34 is fixedly connected to the bearing platform 2; the quasi-zero stiffness device 32 has a high static stiffness And low dynamic stiffness, in a stable state, it can provide a stable supporting force for the bearing platform 2, when it is excited to vibrate, it can amplify the vibration signal, and then actively control to offset the vibration.

In order to prevent the vibration-damping mechanism 3 from forming a triangle to stably support the bearing platform 2 and causing the bearing platform 2 to be unable to vibrate, the connecting rod 33 includes at least two sections of rods, and the ends of two adjacent rods are connected together by a flexible hinge 4, which can realize load bearing Vibration of platform 2.

Specifically, the axes of the motor mount 31 , the quasi-zero stiffness device 32 and the connecting rod 33 in a stable equilibrium state are collinear, which can make the transmission direction of the vibration more accurate, and it is also more convenient to actively cancel the vibration. If the axes of the motor mounting base 31, the quasi-zero stiffness device 32, and the connecting rod 33 are not set to be collinear, they must at least be set to be parallel to each other, otherwise the transmission direction of vibration is too chaotic, and it is not convenient for subsequent active control and elimination of vibration, etc. operate.

In order to make the direction of excitation received by each damping structure wider, the included angle between the axes of the motor mounting base 31, the quasi-zero stiffness device 32 and the connecting rod 33 and the platform bottom plate 1 is 45 degrees, if the motor mounting base 31 , The angle between the axis of the quasi-zero stiffness device 32 and the connecting rod 33 and the platform bottom plate 1 is greater than 45 degrees, which is conducive to the transmission of excitation in the vertical direction in the vibration damping mechanism 3, but is not conducive to a wider horizontal direction The transmission of the excitation on the vibration damping mechanism 3, if the included angle between the axis of the motor mount 31, the quasi-zero stiffness device 32 and the connecting rod 33 and the platform bottom plate 1 is less than 45 degrees, it is conducive to the transmission of excitation in the horizontal direction. The transmission in the damping mechanism 3 is not conducive to the transmission of excitation in the vertical direction in the damping mechanism 3. Therefore, the axis of the motor mount 31, the quasi-zero stiffness device 32 and the connecting rod 33 and the platform bottom plate 1 An included angle of 45 degrees is the optimal setting, which can balance the excitation in all directions to be transmitted in the damping mechanism 3 .

Specifically, the upper ends of the two connecting rods 33 in each damping mechanism group are connected to the load-carrying platform 2 through the same connecting piece 34, and the side connecting the connecting piece 34 and each connecting rod 33 is inclined, and the connecting rods The axis of 33 is perpendicular to the side to which the connector 34 is connected. When the vibration-isolated object vibrates, the vibration can be better transmitted to the vibration-damping mechanism 3 through the above arrangement.

Specifically, the quasi-zero stiffness device 32 includes an active actuator 321, a casing 322, an actuating rod 323 and a fixed block 324. The active actuator 321 is installed in the motor mount 31, and the casing 322 is fixedly connected to the active actuator. The upper end of the device 321, the upper end of the housing 322 is provided with a through hole, 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, and the fixed block 324 Fixedly arranged in the middle part of the actuating rod 323 and the fixed block 324 is located in the housing 322, the first spring 325 is arranged between the upper end of the fixed block 324 and the housing 322, and at least two circumferential springs are arranged on the side of the fixed block 324. The elastic pieces 326 are distributed and contracted, and the two ends of each elastic piece 326 are hinged to the housing 322 and the fixing block 324 respectively.

Working principle: install the displacement sensor, speed sensor and acceleration sensor on the vibration-isolated object, and fix it on the bearing platform 2, use the controller to control, the structure of the controller and the controller to install the displacement sensor, speed sensor and acceleration sensor The control of the sensor is all prior art, so I won’t go into details here. According to the quality of the vibration-isolation object, design and adjust the rigidity of the elastic member 326 and the first spring 325 in the quasi-zero stiffness device 32, so that the vibration-isolation object is installed on the carrying platform 2 Finally, the present invention as a whole can maintain a quasi-zero stiffness state. When the vibration-isolated object vibrates or is vibrated by external excitation, the vibration is transmitted to the quasi-zero stiffness device 32 through each connecting rod 33, thereby pushing the actuating rod 323 to drive the fixed block 324 Vibration occurs together, and the balance of the elastic force direction of the elastic member 326 perpendicular to the axis of the actuating rod 323 is broken, which will push the actuating rod 323 and the fixed block 324 to move together. The traditional linear stiffness vibration isolation system can only be used when the external excitation frequency is high. To play a vibration isolation effect, the three elastic members 326 that have been compressed in the initial situation will provide a negative stiffness effect when the quasi-zero stiffness device 32 moves, reducing the overall stiffness of the quasi-zero stiffness device 32, so that the quasi-zero stiffness device 32 The zero-stiffness device 32 can have a low initial vibration isolation frequency when the frequency of external excitation is low, so as to achieve the low-frequency vibration isolation effect; at the same time, the displacement sensor, the velocity sensor and the acceleration sensor detect the state of vibration, and The signal is transmitted to the controller, and the controller controls the active actuator 321 to provide power to actively offset the above vibration, thereby achieving the effect of vibration reduction.

Specifically, the elastic member 326 adopts a second spring. The contracted second spring can provide elastic force to realize the function of the elastic member 326 .

Specifically, the active actuator 321 adopts one of an electromagnetic actuator, a pneumatic actuator and a piezoelectric actuator. The above-mentioned active actuators 321 can be controlled by the controller to provide corresponding force to counteract the vibration.

Specifically, the housing 322 includes an upper cover 5, a first housing 6, a second housing 7 and a third housing 8, the upper cover 5, the first housing 6, the second housing 7 and the third housing 8 are fixedly connected in sequence, and the through holes Arranged on the upper cover 5, all the ends of the elastic members 326 away from the actuating rod 323 are connected with the second housing 7, and the end of the third housing 8 is fixedly connected with the active actuator 321; the assembly structure of the housing 322 can realize Quick installation is also convenient for adjusting the rigidity of the fixed block 324 inside the housing 322, the second spring and other structures.

Specifically, the connecting rod 33 and the connecting piece 34 are connected by thread, and the thread connection is fast and convenient.

Embodiment 2, as shown in Figure 6, the only difference between Embodiment 2 and Embodiment 1 is that the elastic member 326 uses an Euler beam, which is a common elastic structure and can also be used to provide elastic force to realize the elastic member 326, and the direction of the force provided by the Euler beam is stable, and it will not bend itself like the second spring during work, but the ductility of the Euler beam is not as good as the second spring, that is, it is fixed The moving distance of the block 324 and the actuating rod 323 will be more restricted, which can be selected according to the actual situation.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

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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