A vibration isolator applicable to ultra-low power in an ultra-low temperature environment

Abstract

The present invention discloses a vibration isolator applicable to ultra-low power in an ultra-low temperature environment, belonging to the fields of micro-vibration control and active control in an ultra-low temperature environment. It includes a load platform, a non-linear positive stiffness component, and a negative stiffness active actuator component; the negative stiffness active actuator component includes more than three negative stiffness active actuators uniformly fixed on a bottom plate through an outer shell. The outer end of the main shaft of the negative stiffness active actuator is fixedly connected to the bottom surface of the load platform, and the outer shell of the negative stiffness active actuator is fixed on the bottom plate. The non-linear negative stiffness exhibited by the negative stiffness active actuator compensates for the non-linear positive stiffness of the vibration isolation device over a large range, enabling the vibration isolator to reach a quasi-zero stiffness state; thereby reducing the active force and power provided by the required active actuator, suppressing the temperature rise generated by active control in an ultra-low temperature environment, and achieving the effect of maintaining an ultra-low temperature environment. This vibration isolation device belongs to active control, and the entire device has the characteristics of good controllability, high reliability, low energy consumption, low temperature rise, and strong low-frequency vibration isolation ability.

Description

Technical Field

[0001] The present invention belongs to the fields of micro-vibration control and active control in ultra-low temperature environments, and particularly relates to a vibration isolator suitable for ultra-low power in ultra-low temperature environments. Background Art

[0002] High-performance precision vibration isolation systems have always been an important part of high-end equipment such as ultra-precision measurement. In particular, ultra-precision measurement and vibration reduction in ultra-low temperature environments are more challenging, and their performance also marks the level of a country's high-end equipment manufacturing and top-notch testing.

[0003] Existing vibration isolation technologies are mainly divided into passive, semi-active, and active vibration isolation technologies. For passive vibration isolation systems, common technical solutions are to add elastic elements, damping elements, and even inertial elements between the vibration source and the system. Therefore, the important parameters of passive vibration isolation systems are fixed and uncontrollable during the vibration isolation process, and it is difficult to effectively isolate external vibrations in various situations, so they cannot meet the working requirements of ultra-high-precision equipment. Semi-active vibration isolation can usually change the damping characteristics of the vibration isolation device, thereby indirectly changing the output of the control force. The vibration isolation effect is better than that of passive vibration isolation. However, compared with active vibration isolation systems, the control force provided by semi-active vibration isolation systems is restricted by the vibration isolation device, so the control effect is often inferior to that of active control. Active vibration isolation systems generally add an active force actuator in parallel or in series on the basis of passive vibration isolation, or use an active force actuator to replace some or all of the components of the passive vibration isolation device. During the vibration isolation process, the sensor device obtains information and feeds it back to the control device, and then issues appropriate instructions to the active force actuator to output a controllable active force, which can effectively isolate environmental vibrations. However, it often needs to output active force for a long time, resulting in increased energy consumption, power, and heat generation, and it is impossible to maintain the ultra-low temperature environment required by the equipment in ultra-low temperature environments.

[0004] Traditional active vibration isolation technologies often increase the stiffness of the rigid spring to increase the natural frequency of the vibration isolation system in order to obtain good vibration isolation effects at low frequencies. At the same time, the large stiffness will bring defects such as increased output of the active force of the active force actuator, increased power consumption, and increased heat generation. Therefore, it is very important and necessary to study new low-power vibration control methods at ultra-low temperatures for high-precision measurement equipment working in ultra-low temperature environments. Summary of the Invention

[0005] In order to reduce the active force required for active control and provide the feasibility of low-power vibration isolation at ultra-low temperatures, the present invention provides a vibration isolator suitable for ultra-low power in ultra-low temperature environments.

[0006] An isolator applicable to ultra-low power in ultra-low temperature environment includes a load platform 2 and a non-linear positive stiffness component. The non-linear positive stiffness component includes a central axis 1, six spring connecting columns 3, six geometric anti-spring plates 9 and a bottom plate 5. The upper end of the central axis 1 is connected to the center of the load platform 2 by thread, the lower end of the central axis 1 is connected to a displacement sensor 6, and the bottom of the displacement sensor 6 is fixedly connected to the top surface of the bottom plate 5 by thread. The six spring connecting columns 3 are evenly distributed on the outer periphery of the bottom plate 5 with the central axis 1 as the center. One ends of the six geometric anti-spring plates 9 are respectively fixedly connected to the upper ends of the corresponding six spring connecting columns 3, and the other ends of the six geometric anti-spring plates 9 are respectively fixedly connected to a connecting ring 7 sleeved on the central axis 1.

[0007] It also includes a negative stiffness active actuator component.

[0008] The negative stiffness active actuator component includes more than three negative stiffness active actuators 4. The more than three negative stiffness active actuators 4 are evenly fixed on the bottom plate 5 through a housing 404, and the outer ends of the main shafts 401 of the more than three negative stiffness active actuators 4 are fixedly connected to the bottom surface of the load platform 2.

[0009] Negative stiffness is generated by the interaction between the inner magnet ring 403 and the outer magnet ring 402 in the negative stiffness active actuator, which is used to compensate most of the non-linear positive stiffness provided by the six geometric anti-spring plates 9, so that the isolator reaches a quasi-zero stiffness state.

[0010] Preferably, the negative stiffness active actuator component 4 includes three negative stiffness active actuators.

[0011] The beneficial technical effects of the present invention are reflected in the following aspects:

[0012] 1. Aiming at the signal distortion caused by ultra-low frequency vibration generated by high-precision scientific devices, and the limitations of traditional vibration isolation technologies for reducing external vibration, such as high power consumption and high temperature rise, the present invention proposes to introduce negative stiffness technology into the active control vibration isolation system. Through the mechanism of large-range cancellation of negative stiffness and the positive stiffness of the vibration isolation structure itself, the positive stiffness of the vibration isolation structure itself is reduced, thereby reducing the active force required by the active actuator, and thus reducing the active control power. The simulation results show that the reduction effect of the active force can reach 80%, further reducing the power consumption and temperature rise generated by active control in ultra-low temperature environment, and realizing ultra-low power vibration isolation of precision instruments at ultra-low temperature.

[0013] 2. A pair of magnet rings on the negative stiffness active actuator of the present invention form a negative stiffness unit, which has negative stiffness characteristics. The inner magnet ring is fixed on the main shaft of the actuator, and the outer magnet ring is fixed to the actuator housing. Refer to Figure 3 B in. When the inner and outer magnet rings are aligned in height, they are in the equilibrium position, and at this time, the negative stiffness unit does not generate axial force. Refer to Figure 3For A in it, when the main shaft of the active actuator outputs upward force, the inner magnet ring in the negative stiffness active actuator will move upward along with the main shaft. When it just deviates from the equilibrium position, a large axial force in the same direction as the displacement will be generated, and then this axial force will rapidly decrease as the displacement increases, showing the negative stiffness characteristic. Similarly, refer to Figure 3 For C in it, when the main shaft of the active actuator outputs downward force, the inner magnet ring in the negative stiffness active actuator will move downward along with the main shaft. When it just deviates from the equilibrium position, a large axial force in the same direction as the displacement will be generated, and then this axial force will rapidly decrease as the displacement increases, also showing the negative stiffness characteristic. Introducing this non-linear negative stiffness mechanism into the active vibration isolation system can greatly reduce the self-stiffness of the vibration isolation system. At the same time, cooperating with the non-linear positive stiffness component can ensure the load-bearing capacity of the system. The non-linear negative stiffness mechanism can greatly improve the vibration reduction performance of the vibration isolation system, enabling it to achieve the expected vibration isolation effect while reducing the active force output, thereby reducing the active control power and the temperature rise generated by active control in the ultra-low temperature environment, achieving the effect of maintaining the ultra-low temperature environment. Brief Description of the Drawings

[0014] Figure 1 It is the front view of the structure of the embodiment of the present invention.

[0015] Figure 2 It is the cross-sectional view of the structure of the embodiment of the present invention.

[0016] Figure 3 It is the cross-sectional view of the negative stiffness active actuator 4 in the structure of the embodiment of the present invention.

[0017] Figure 4 It is the fully suspended load-bearing structure composed of geometric anti-springs in the structure of the embodiment of the present invention.

[0018] The serial numbers in the above figure: central axis 1, load platform 2, spring connection column 3, negative stiffness active actuator 4, bottom plate 5, displacement sensor 6, central connection ring 7, spring pressure plate 8, geometric anti-spring plate 9, main shaft 401, inner magnet ring 403, outer magnet ring 402, outer shell 404. Detailed Embodiment

[0019] The present invention will be further introduced in detail through embodiments in combination with the attached drawings.

[0020] Embodiment 1

[0021] Refer to Figure 1 , a vibration isolator applicable to ultra-low power in ultra-low temperature environment includes a load platform 2, a non-linear positive stiffness component, and a negative stiffness active actuator component 4.

[0022] Refer to Figure 2, the non-linear positive stiffness component includes a central shaft 1, six spring connecting columns 3, six geometric anti-spring plates 9, and a bottom plate 5.

[0023] See Figure 4 , the upper end of the central shaft 1 is connected to the center of the load platform 2 by threads, and the relative position is finely adjusted by thread connectors. The lower end of the central shaft 1 is connected to the displacement sensor 6, and the bottom tooling of the displacement sensor 6 contacts the top surface of the bottom plate 5; when the load platform 2 drives the central shaft 1 to vibrate up and down, the displacement sensor 6 collects displacement signals. The connecting ring 7 is fixed to the upper part of the central shaft 1, and the relative position is adjusted by thread connectors. The connecting ring 7 simultaneously connects one end of the six geometric anti-spring plates 9, and the other ends of the six geometric anti-spring plates 9 are respectively pressed against the corresponding spring connecting columns 3 through spring pressing plates 8. The geometric anti-spring plate 9 is a steel plate made of spring steel, and the edge is a transition curve. For different sizes of loads, the bearing capacity can be changed by changing the thickness and material of the geometric anti-spring plate 9. By adjusting the height of the connecting ring 7, the six geometric anti-spring plates 9 are pre-deformed to generate non-linear positive stiffness. The six spring connecting columns 3 fix the six geometric anti-spring plates 9 on the circumference of the bottom plate 5.

[0024] See Figure 2 , the negative stiffness active actuator component includes three negative stiffness active actuators.

[0025] See Figure 3 , the negative stiffness active actuator 4 includes a main shaft 401, an inner magnet ring 403, an outer magnet ring 402, and a housing 404.

[0026] The three negative stiffness active actuators are evenly fixed on the circumference of the bottom plate 5 through the housing 404, and the outer ends of the main shafts 401 of the three negative stiffness active actuators are fixedly connected to the bottom surface of the load platform 2 by thread connectors.

[0027] See Figure 3 B in Figure 3 At this time, the center lines of the inner magnet ring 403 and the outer magnet ring 402 coincide and are centered in height. At this time, it is in the equilibrium position, and the negative stiffness unit does not generate axial force. See Figure 3 A in

[0028] When the main shaft 401 of the active actuator exerts an upward force, driving the inner magnet ring 403 to deviate upward from the equilibrium position, an axial force in the same direction as the displacement is generated, and the axial force suddenly increases when just deviating from the equilibrium position, and then rapidly decreases as the displacement increases, showing negative stiffness characteristics. Similarly, see Figure 4, the nonlinear positive stiffness component realizes a fully suspended load-bearing structure, and in conjunction with the negative stiffness mechanism, it can greatly reduce the active force required for active control.

[0029] During use, first adjust the height to the equilibrium position by adjusting the threaded engagement length between the central shaft 1 and the load platform 2, then activate the three negative stiffness active actuators 4, and calculate the magnitude of the output current based on the signal from the displacement sensor 6, thereby controlling the output active force. The negative stiffness active actuator 4 has no hysteresis characteristics and is suitable for short-stroke closed-loop servo applications.

[0030] It is easy for those skilled in the art to understand that the above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A vibration isolator suitable for ultra-low power in an ultra-low temperature environment, comprising a load platform (2) and a non-linear positive stiffness component. The non-linear positive stiffness component includes a central shaft (1), six spring connecting columns (3), six geometric anti-spring plates (9) and a bottom plate (5); the upper end of the central shaft (1) is connected to the center of the load platform (2) by threads, the lower end of the central shaft (1) is connected to a displacement sensor (6), and the bottom of the displacement sensor (6) is fixedly connected to the top surface of the bottom plate (5) by threads. The six spring connecting columns (3) are evenly distributed on the outer periphery of the bottom plate (5) with the central shaft (1) as the center; one ends of the six geometric anti-spring plates (9) are respectively fixedly connected to the upper ends of the corresponding six spring connecting columns (3), and the other ends of the six geometric anti-spring plates (9) are respectively fixedly connected to a connecting ring (7) sleeved on the central shaft (1); characterized in that: It further includes a negative stiffness active actuator assembly; The negative stiffness active actuator assembly includes more than three negative stiffness active actuators (4); the more than three negative stiffness active actuators (4) are evenly fixed on the bottom plate (5) through the outer shell (404), and the outer ends of the main shafts (401) of the more than three negative stiffness active actuators (4) are fixedly connected to the bottom surface of the load platform (2); Negative stiffness is generated by the interaction between the inner magnet ring (403) and the outer magnet ring (402) in the negative stiffness active actuator, which is used to compensate most of the nonlinear positive stiffness provided by the six geometric anti-spring plates (9), so that the vibration isolator reaches the quasi-zero stiffness state.

2. The vibration isolator applicable to ultra-low power in an ultra-low temperature environment according to claim 1, wherein: The negative stiffness active actuator (4) includes three negative stiffness active actuators.

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