Multi-degree-of-freedom high-rigidity air floating spring active shock absorber

Abstract

The invention discloses a multi-degree-of-freedom high-rigidity air floating spring active shock absorber which is characterized in that a supporting plate and a bottom plate are arranged at the upper end and the lower end of a shock absorber body respectively, and mover parts of a horizontal voice coil motor and a vertical voice coil motor are connected with the bottom plate; stator parts of the horizontal voice coil motor and the vertical voice coil motor are connected with a supporting plate, the supporting plate is provided with a speed sensor, and a target surface part of a displacement sensor is fixedly connected with the supporting plate. The shock absorber body is provided with a shock absorber base connected with the bottom plate, a sensor and a fixing base part of the displacement sensor are fixedly installed on the shock absorber base, the shock absorber base is provided with a cavity, a middle supporting base is installed in the cavity in a suspended mode, the lower end of the middle supporting base is sleeved with an elastic piece, and when the middle supporting base moves downwards, the elastic piece is compressed. The diaphragm is hermetically connected with the upper end surface of the shock absorber seat and the upper end surface of the middle supporting seat respectively; the middle supporting seat is provided with an inserting groove, the upper end of the swing rod is fixedly connected with the supporting plate, and the lower end of the swing rod is fixedly connected with the bottom face of the inserting groove. The supporting plate and the shock absorber base are fixedly connected through a limiting structure. Ground vibration is isolated, platform vibration caused by sliding block movement is restrained, and the height is automatically adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of active shock absorbers, and particularly to a multi-degree-of-freedom high-stiffness air-floating spring active shock absorber. Background Art

[0002] Lithography equipment or inspection equipment has extremely low vibration environment requirements for the ultra-precision motion platforms it is equipped with, and requires the shock absorber to attenuate most of the micro-vibrations transmitted from the ground. Moreover, when the slider of the shock absorber performs acceleration and deceleration movements, it will also cause platform vibrations. To meet the requirements of the equipment on the shock-absorbing platform (high precision, high productivity), the shock absorber also needs to be able to quickly suppress the platform vibrations to a level that meets the precision operation requirements.

[0003] Passive shock absorbers have the characteristic of a relatively low fixed vibration frequency, and can better isolate the ground micro-vibrations in the medium and high frequency bands, but they will amplify the vibrations within their own fixed vibration frequency band, and cannot quickly suppress the platform vibrations caused by the slider movement. The stabilization time for self-stabilization is relatively long, and it cannot meet the shock absorption requirements of the equipment on the platform.

[0004] Most active shock absorbers have the characteristic of low stiffness. They can effectively isolate the ground micro-vibrations, but when the slider on the platform performs high-speed acceleration and deceleration movements, it will cause the platform to swing around the horizontal axis with a relatively large swing amplitude. This swing will also increase with the height of the platform. The higher the platform, the greater the vibration amplitude at the top of the platform. In the Z-axis direction of the precision motion platform, there are often precision devices such as optical modules arranged, which require an extremely low vibration environment. Therefore, a shock absorber for a high-acceleration and deceleration motion platform needs to have a relatively high stiffness in the Z-axis direction to reduce the swing amplitude of the platform.

[0005] Therefore, there is an urgent need for a multi-degree-of-freedom high-stiffness air-floating spring active shock absorber that can solve one or more of the above problems. Summary of the Invention

[0006] To solve one or more problems existing in the prior art, the present invention provides a multi-degree-of-freedom high-stiffness air-floating spring active shock absorber. The technical solution adopted by the present invention to solve the above problems is: a multi-degree-of-freedom high-stiffness air-floating spring active shock absorber, which includes: a shock absorber body, a bottom plate is provided at the lower end of the shock absorber body, a support plate is provided at the upper end of the shock absorber body, the moving part of the horizontal voice coil motor is fixedly connected to the bottom plate, and the moving part of the vertical voice coil motor is fixedly connected to the bottom plate;

[0007] The stator part of the horizontal voice coil motor is fixedly connected to the support plate, the stator part of the vertical voice coil motor is fixedly connected to the support plate, the support plate is equipped with a vertical direction speed sensor and a horizontal direction speed sensor, and the target surface part of the vertical and horizontal displacement sensors is fixedly connected to the support plate;

[0008] The shock absorber body is provided with a shock absorber seat. The sensor and the fixed seat part of the vertical and horizontal displacement sensors are fixedly installed on the shock absorber seat. The shock absorber seat is fixedly connected to the bottom plate. The shock absorber seat is provided with a chamber opening towards the support plate. The chamber is suspended with an intermediate support seat installed therein. The lower end of the intermediate support seat is sleeved with an elastic member. The first end of the elastic member abuts against the bottom surface of the chamber, and the second end of the elastic member abuts against the intermediate support seat. When the intermediate support seat moves downward, the elastic member is compressed. The diaphragm is hermetically connected to the upper end surface of the shock absorber seat and the upper end surface of the intermediate support seat respectively. The diaphragm seals the opening of the chamber, and the chamber forms a sealed chamber. The chamber is connected to the outside through a valve;

[0009] The intermediate support seat is provided with a slot opening towards the support plate. The upper end of the swing rod is fixedly connected to the support plate, and the lower end of the swing rod is inserted into the slot and fixedly connected to the bottom surface of the slot;

[0010] The support plate and the shock absorber seat are connected through a limiting structure, and the limiting structure limits the horizontal and vertical displacement amplitudes of the support plate.

[0011] In some embodiments, the elastic member is a steel spring and is vertically arranged.

[0012] In some embodiments, the valve is a throttle valve. The throttle valve is installed on the outer side surface of the shock absorber seat, and the throttle valve is communicated with the chamber.

[0013] Further, the throttle valve is connected to an electric control valve assembly, and the electric control valve assembly is used to control the intake and exhaust of the chamber.

[0014] Further, the electric control valve assembly is installed on the bottom plate.

[0015] In some embodiments, the outer side of the diaphragm is fastened to the upper end surface of the shock absorber seat by an outer locking ring, and the inner side of the diaphragm is fastened to the upper end surface of the intermediate support seat by an inner locking ring.

[0016] In some embodiments, the diaphragm is annular.

[0017] In some embodiments, the swing rod and the bottom surface of the slot are fastened by screw connection, and the swing rod and the bottom surface of the slot are sealed by pressing with an O-ring.

[0018] In some embodiments, the limiting structure includes a limiter and a fastening nut. The upper end of the limiter is connected to the support plate and is arranged on the lower surface of the support plate. The lower end of the limiter is fixedly connected to the shock absorber seat through the fastening nut.

[0019] Furthermore, the limiting structure further includes: an elastic ring, a fixing block, and a gasket. The elastic ring is sleeved on the limiter. A groove for installing the elastic ring is formed on the surface of the shock absorber seat facing the bottom plate. The fixing block fixes the elastic ring in the groove. The inner side of the elastic ring closely adheres to the limiter. The gasket is sleeved on the limiter, and the gasket is located between the fixing block and the fastening nut.

[0020] The technical effects achieved by the present invention are as follows: The chamber and the diaphragm form an adjustable airbag structure, that is, an air-floating shock absorber structure is realized. The elastic member (steel spring) is connected in parallel with the airbag structure in the Z-axis direction. That is, the total stiffness of the shock absorber in the Z-axis direction is the sum of the stiffness of the elastic member (steel spring) and the airbag structure. Among them, the stiffness of the elastic member (steel spring) is the dominant part. Finally, while increasing the stiffness in the Z-axis direction, the load capacity is improved, and the swing amplitude of the platform is reduced.

[0021] The height of the airbag structure is controlled by using an electronically controlled valve assembly, and then in cooperation with a height displacement sensor, the automatic height adjustment in the Z-axis direction is realized; a horizontal swing rod structure is formed by using a swing rod to realize the decoupling of the stiffness of the elastic member (steel spring) in the horizontal direction, which is convenient for adjusting the horizontal stiffness of the shock absorber to meet the customer's requirements.

[0022] The shock absorber is equipped with speed sensors in the horizontal and vertical directions, and voice coil motors in the horizontal and vertical directions. They form a set of active shock absorption systems. The controller, speed sensors, voice coil motors, and the drive program of the motors together constitute a shock absorption feedback control loop. The vibration speed of six degrees of freedom of the platform is obtained by real-time transformation of the matrix data of the longitude and latitude coordinates detected by multiple speed sensors. The controller issues shock absorption instructions according to these data in sequence, and the voice coil motors apply damping forces in six directions to realize the vibration feedback control of the platform and the ground vibration feedforward control, effectively isolating the ground vibration. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the present invention;

[0024] Figure 2 It is a cross-sectional view of the present invention;

[0025] Figure 3 It is a partial cross-sectional view of the present invention.

[0026] In the figure, 1 is a support plate; 2 is a horizontal voice coil motor; 3 is a limiting structure, which includes 31 a limiter, 32 an elastic ring, 33 a fixing block, 34 a gasket, and 35 a fastening nut; 4 is a shock absorber body, which includes 41 a swing rod, 42 an inner locking ring, 43 an outer locking ring, 44 a diaphragm, 45 a shock absorber seat, 46 a throttle valve, 47 an elastic member, 48 an intermediate support seat, and 49 an O-ring; 5 is an electromagnetic valve assembly; 6 is a bottom plate; 7 is a vertical voice coil motor; 8 is a vertical direction speed sensor; 9 is a horizontal direction speed sensor; 10 is a motor and sensor interface; 11 is a vertical and horizontal displacement sensor. Detailed implementation manners

[0027] To make the above objects, features, and advantages of the present invention more comprehensible, the following describes the detailed implementation manners of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand the present invention. However, the present invention can be implemented in many other ways different from this description, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0028] As Figures 1 - 3 shown, the present application discloses a multi-degree-of-freedom high-rigidity air-floating spring active shock absorber, which includes: a shock absorber body 4, a bottom plate 6 is arranged at the lower end of the shock absorber body 4, a support plate 1 is arranged at the upper end of the shock absorber body 4, the mover part of the horizontal voice coil motor 2 is fixedly connected to the bottom plate 6, and the mover part of the vertical voice coil motor 7 is fixedly connected to the bottom plate 6;

[0029] Combined with Figure 1 shown, the stator part of the horizontal voice coil motor 2 is fixedly connected to the support plate 1, the stator part of the vertical voice coil motor 7 is fixedly connected to the support plate 1, the support plate 1 is provided with a vertical direction speed sensor 8 and a horizontal direction speed sensor 9, and the target surface part of the vertical and horizontal displacement sensor 11 is fixedly connected to the support plate 1;

[0030] Combined with Figure 2As shown, the shock absorber body 4 is provided with a shock absorber seat 45. The sensor and fixed seat part of the vertical and horizontal displacement sensor 11 are fixedly installed on the shock absorber seat 45. The shock absorber seat 45 is fixedly connected to the bottom plate 6. The shock absorber seat 45 is provided with a chamber opening towards the support plate 1. An intermediate support seat 48 is suspended in the chamber. A lower end of the intermediate support seat 48 is sleeved with an elastic member 47. A first end of the elastic member 47 abuts against a bottom surface of the chamber, and a second end of the elastic member 47 abuts against the intermediate support seat 48. When the intermediate support seat 48 moves downward, the elastic member 47 is compressed. A diaphragm 44 is hermetically connected to an upper end surface of the shock absorber seat 45 and an upper end surface of the intermediate support seat 48 respectively. The diaphragm 44 seals the opening of the chamber, and the chamber forms a sealed chamber. The chamber is connected to the outside through a valve;

[0031] Combined with Figure 2 As shown, the intermediate support seat 48 is provided with a slot opening towards the support plate 1. An upper end of a swing rod 41 is fixedly connected to the support plate 1. A lower end of the swing rod 41 is inserted into the slot and fixedly connected to a bottom surface of the slot;

[0032] Combined with Figure 1 、 Figure 3 As shown, the support plate 1 and the shock absorber seat 45 are connected through a limiting structure 3. The limiting structure 3 limits horizontal and vertical displacement amplitudes of the support plate 1. The limiting structure 3 can be provided with three or more, and a position of the limiting structure 3 is set according to requirements.

[0033] It should be noted that the elastic member 47 can be a steel spring; the valve is a throttle valve 46. The throttle valve 46 is installed on an outer side surface of the shock absorber seat 45. The throttle valve 46 is communicated with the chamber. The throttle valve 46 is connected to an electric control valve assembly 5. The electric control valve assembly 5 is used to control air intake and air outlet of the chamber, so as to perform controllable and automatic height adjustment on an airbag structure (air floating shock absorption structure) formed by the diaphragm 44 and the chamber. Further, combined with Figure 1 As shown, the electric control valve assembly 5 is installed on the bottom plate 6. The bottom plate 6 is further provided with corresponding motor and sensor interfaces 10.

[0034] It should be noted that the horizontal voice coil motor 2 and the vertical voice coil motor 7 are used to provide a reverse force for shock absorption. The number of sensors and electric control components in this application is set according to actual requirements.

[0035] Specifically, combined with Figure 2As shown, the diaphragm 44 is annular. The outer side of the diaphragm 44 is fastened to the upper end surface of the shock absorber seat 45 by an outer locking ring 43, and the inner side of the diaphragm 44 is fastened to the upper end surface of the intermediate support seat 48 by an inner locking ring 42.

[0036] Specifically, as shown in Figure 2 The swing rod 41 is fastened to the bottom surface of the slot by a threaded connection, and the swing rod 41 and the bottom surface of the slot are pressed and sealed by an O-ring 49. The swing rod 41 and other components form a horizontal swing rod structure to achieve stiffness decoupling of the elastic member 47 in the horizontal direction, so as to facilitate the adjustment of the horizontal stiffness of the shock absorber.

[0037] Specifically, as shown in Figure 3 The limiting structure 3 includes a limiter 31 and a fastening nut 35. The upper end of the limiter 31 is connected to the support plate 1 and is arranged on the lower surface of the support plate 1. The lower end of the limiter 31 is fixedly connected to the shock absorber seat 45 through the fastening nut 35. The limiter 31 is provided with an adjusting bolt (not indicated in the drawing), and the adjusting bolt passes through the support plate 1 and is connected to the upper end surface of the limiter 31. The insertion depth of the adjusting bolt limits the vertical displacement amplitude of the support plate 1. Similarly, the diameter of the through hole of the adjusting bolt passing through the support plate 1 also limits the horizontal displacement amplitude of the support plate 1;

[0038] Furthermore, the limiting structure 3 further includes an elastic ring 32, a fixing block 33 and a gasket 34. The elastic ring 32 is sleeved on the limiter 31. A groove for installing the elastic ring 32 is formed on the surface of the shock absorber seat 45 facing the bottom plate 6. The fixing block 33 fixes the elastic ring 32 in the groove. The inner side of the elastic ring 32 is closely attached to the limiter 31. The gasket 34 is sleeved on the limiter 31, and the gasket 34 is located between the fixing block 33 and the fastening nut 35;

[0039] The support plate 1 and the shock absorber seat 45 are connected by using the limiting structure 3 to limit the horizontal and vertical displacement amplitudes of the support plate 1.

[0040] It should be noted that the shock absorber body 4 supports the load. The stiffness of the shock absorber can be adjusted by adjusting the three-dimensional parameters of the elastic member 47 (steel spring) and the swing rod 41 therein to meet the requirements of high vertical stiffness and low horizontal stiffness. The shock absorber body 4, the vertical and horizontal displacement sensors 11, the electro-control valve assembly 5, the horizontal voice coil motor 2, the vertical voice coil motor 7 and the controller form an automatic leveling system. The controller runs the control system, and the controller and the system can be existing control devices and systems. The vertical direction speed sensor 8, the horizontal direction speed sensor 9, the vertical voice coil motor 7, the horizontal voice coil motor 2 and the controller form a vibration feedback control system.

[0041] Aiming at the disadvantage of insufficient stiffness in the Z-axis direction of the existing shock absorber, in the present application, an elastic member and a corresponding structure are arranged inside the airbag structure (air floating shock absorption structure) formed by the diaphragm and the chamber. The elastic member (steel spring) is connected in parallel with the airbag structure in the Z-axis direction. That is, the total stiffness in the Z-axis direction of the shock absorber is the sum of the stiffness of the elastic member (steel spring) and the airbag structure. Among them, the stiffness of the elastic member (steel spring) is the dominant part. Finally, while increasing the stiffness in the Z-axis direction, the load capacity is improved and the swing amplitude of the platform is reduced.

[0042] Among them, the Z-axis direction of the elastic member (steel spring) is coupled with the horizontal stiffness. Selecting a spring with a large Z-axis direction stiffness will also result in a large horizontal direction stiffness.

[0043] The electro-control valve assembly is used to control the height of the airbag structure, and then cooperate with the height displacement sensor to realize the automatic height adjustment in the Z-axis direction. The swing rod is used to form a horizontal swing rod structure to realize the decoupling of the horizontal stiffness of the elastic member (steel spring), which is convenient for adjusting the horizontal stiffness of the shock absorber to meet the customer's needs.

[0044] By designing a limit structure (multiple limit structures can be designed), the movement amplitude of the components in the horizontal and height directions is limited. When the shock absorber is not inflated and floating, the load is stably supported by the limit structure. Among them, the elastic ring in the limit structure can realize the accurate centering positioning during the installation of the limiter.

[0045] The shock absorber is equipped with speed sensors in the horizontal and vertical directions, as well as voice coil motors in the horizontal and vertical directions. They form an active shock absorption system. The controller, speed sensors, voice coil motors and the drive program of the motors together form a shock absorption feedback control loop. The vibration speed of the six degrees of freedom of the platform is obtained by the real-time transformation of the matrix data of the longitude and latitude coordinates detected by multiple speed sensors. The controller issues shock absorption instructions according to these data in sequence, and the voice coil motors apply damping forces in six directions to realize platform vibration feedback control, ground vibration feedforward control and motion disturbance feedforward control, effectively isolating ground vibration and motion disturbance.

[0046] Among them, the ground vibration feedforward control detects the ground vibration velocity by velocity sensors in three directions (X, Y, and Z axis directions), and applies a reverse acting force by a voice coil motor to reduce part of the ground vibration before it is transmitted to the platform through the shock absorber;

[0047] Among them, for the motion disturbance feedforward control, the acceleration and deceleration movement of the linear motor slider on the platform (support plate) will apply a force to the platform and push the platform to vibrate. When the platform linear motor moves, the acceleration and position signals are transmitted to the active vibration reduction system as the feedforward quantity of vibration control. The system commands the voice coil motor to output a reverse force and torque to cancel the disturbing force applied to the platform by the acceleration and deceleration movement of the slider, thereby reducing the peak acceleration and vibration amplitude of the platform, and shortening the stabilization time of the platform (the time required to reduce vibration after the slider movement on the platform stops), and improving the working beat of the platform.

[0048] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0049] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] The above-described embodiments only represent one or more implementation manners of the present invention, and the description is relatively specific and detailed, but it should not be construed as a limitation to the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A multi-degree-of-freedom high-stiffness air spring active shock absorber, characterized in that, Comprising: A shock absorber body, a bottom plate is provided at the lower end of the shock absorber body, a support plate is provided at the upper end of the shock absorber body, the moving part of the horizontal voice coil motor is fixedly connected to the bottom plate, and the moving part of the vertical voice coil motor is fixedly connected to the bottom plate; The stator part of the horizontal voice coil motor is fixedly connected to the support plate, the stator part of the vertical voice coil motor is fixedly connected to the support plate, the support plate is equipped with a vertical direction speed sensor and a horizontal direction speed sensor, and the target surface part of the vertical and horizontal displacement sensors is fixedly connected to the support plate; The shock absorber body is provided with a shock absorber seat, the sensor and fixed seat part of the vertical and horizontal displacement sensors are fixedly installed on the shock absorber seat, the shock absorber seat is fixedly connected to the bottom plate, the shock absorber seat is provided with a chamber opening towards the support plate, an intermediate support seat is suspended in the chamber, an elastic member is sleeved on the lower end of the intermediate support seat, a first end of the elastic member abuts against the bottom surface of the chamber, a second end of the elastic member abuts against the intermediate support seat, the elastic member is compressed when the intermediate support seat moves downward, a diaphragm is hermetically connected to the upper end surface of the shock absorber seat and the upper end surface of the intermediate support seat respectively, the diaphragm seals the opening of the chamber, the chamber forms a sealed chamber, and the chamber is connected to the outside through a valve; The intermediate support seat is provided with a slot opening towards the support plate, the upper end of the swing rod is fixedly connected to the support plate, and the lower end of the swing rod is inserted into the slot and fixedly connected to the bottom surface of the slot; The support plate and the shock absorber seat are connected by a limiting structure, and the limiting structure limits the horizontal and vertical displacement amplitudes of the support plate.

2. The multi-degree-of-freedom high-stiffness air spring active shock absorber according to claim 1, characterized in that The elastic member is a steel spring.

3. The multi-degree-of-freedom high-rigidity air spring active shock absorber according to claim 1, characterized in that, The valve is a throttle valve, the throttle valve is installed on the outer side surface of the shock absorber seat, and the throttle valve is communicated with the chamber.

4. The multi-degree-of-freedom high-rigidity air spring active shock absorber according to claim 3, characterized in that, The throttle valve is connected to an electric control valve assembly, and the electric control valve assembly is used to control the intake and exhaust of the chamber.

5. The multi-degree-of-freedom high-stiffness air spring active shock absorber according to claim 4, characterized in that, The electric control valve assembly is installed on the bottom plate.

6. The multi-degree-of-freedom high-stiffness air spring active shock absorber according to claim 1, characterized in that, The outer side of the diaphragm is fastened to the upper end surface of the shock absorber seat by an outer locking ring, and the inner side of the diaphragm is fastened to the upper end surface of the intermediate support seat by an inner locking ring.

7. The multi-degree-of-freedom high-rigidity air spring active shock absorber according to claim 1, characterized in that, The diaphragm is annular.

8. The multi-degree-of-freedom high-rigidity air spring active shock absorber according to claim 1, characterized in that The swing rod and the bottom surface of the slot are fastened by threaded connection and sealed by pressing with an O-ring.

9. The multi-degree-of-freedom high-rigidity air spring active shock absorber according to claim 1, wherein, The limiting structure includes: a limiter and a fastening nut, the upper end of the limiter is connected to the support plate and is arranged on the lower surface of the support plate, and the lower end of the limiter is fixedly connected to the shock absorber seat through the fastening nut.

10. The multi-degree-of-freedom high-rigidity air spring active shock absorber according to claim 9, characterized in that, The limiting structure further includes: an elastic ring, a fixing block and a gasket, the elastic ring is sleeved on the limiter, a groove for installing the elastic ring is formed on the surface of the shock absorber seat facing the bottom plate, the fixing block fixes the elastic ring in the groove, the inner side of the elastic ring closely adheres to the limiter, the gasket is sleeved on the limiter, and the gasket is located between the fixing block and the fastening nut.

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