Piezoelectric type active and passive hybrid vibration isolation platform

Abstract

The invention relates to a piezoelectric type active and passive hybrid vibration isolation platform, and belongs to the field of vibration active and passive hybrid control. The three supporting leg lower adapter blocks are annularly arranged on the upper surface of the bottom plate; two piezoelectric driving assemblies are symmetrically arranged at the top of each supporting leg lower adapter block; the top plate is horizontally arranged above the bottom plate; the adapter blocks on the three supporting legs are annularly arranged on the lower surface of the top plate; two flexible Hooke hinges are symmetrically arranged at the bottom of the adapter block on each supporting leg; one force sensor is correspondingly arranged on each flexible Hooke hinge; the flexible guide element upper cover and the flexible guide element lower cover coaxially cover two ends of the flexible guide element; each lower cover is installed on the top of one piezoelectric driving assembly, and the upper cover is in butt joint with one flexible Hooke hinge. According to the platform, the piezoelectric actuation device is adopted to apply active pointing control, the paired diaphragm springs are adopted as passive vibration isolation elements, the piezoelectric actuation device and the diaphragm springs are connected in series, full-band vibration control can be achieved, and the stability of spacecraft effective load visual axis pointing is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of vibration active-passive hybrid control, and relates to a piezoelectric active-passive hybrid vibration isolation platform. BACKGROUND

[0002] With the continuous improvement of the performance of a spacecraft, the stability of the payload viewing axis is required to be higher. The active-passive hybrid vibration isolation technology can realize vibration control in a wide frequency band, is more adaptable than the passive vibration isolation technology, and is more reliable than the pure active vibration isolation technology, so the active-passive hybrid vibration isolation technology has a broad application prospect.

[0003] The existing active-passive hybrid vibration isolation platform mainly adopts a voice coil actuator or a piezoelectric actuator as an active element and adopts a spring as a passive element. For the voice coil active-passive hybrid vibration isolation platform, the vibration control frequency band range is related to the natural frequency of the passive part and the characteristics of the voice coil actuator itself, and the vibration above the natural frequency can be efficiently suppressed. For the vibration in the frequency band below the natural frequency, the ability of the voice coil actuator to convert voltage into control force is reduced due to the influence of the stiffness of the passive element, and the lower the frequency, the worse the control ability, which limits the further improvement of the viewing axis stability in the full frequency band. For the piezoelectric active-passive hybrid vibration isolation platform, a control force with a large amplitude can be output in a low frequency range, and the vibration in the full frequency band can be controlled in combination with the passive element. However, the piezoelectric actuator can only output a limited displacement, and a displacement amplification mechanism is usually required to ensure that the platform has sufficient displacement control margin.

[0004] In addition, in order to realize the mutual decoupling of the control forces between the legs of the platform, a normal Stewart platform configuration is usually selected, and a rotary kinematic pair is designed at the ends of the legs, but the friction of the kinematic pair can seriously affect the micro-vibration control effect of the platform, and the design of the end hinges of the legs and the motion guide elements needs to be improved. SUMMARY

[0005] The technical problem solved by the application is to overcome the shortcomings of the prior art, and to provide a piezoelectric active-passive hybrid vibration isolation platform. The platform uses a piezoelectric actuator to apply active pointing control, uses a pair of diaphragm springs as passive vibration isolation elements, and the two are connected in series, so that the vibration in the full frequency band can be controlled, and the stability of the viewing axis pointing of the spacecraft payload can be ensured.

[0006] The technical solution of the application is:

[0007] The piezoelectric active-passive hybrid vibration isolation platform comprises a top plate, a flexible hinge, three upper adapter blocks of legs, an upper cover of a flexible guide element, six flexible guide elements, a force sensor, a lower cover of the flexible guide element, a piezoelectric driving assembly, three lower adapter blocks of the legs, and a bottom plate.

[0008] The bottom plate is a horizontally placed plate-shaped structure; the three leg lower adapter blocks are annularly mounted on the upper surface of the bottom plate; the top of each leg lower adapter block is symmetrically provided with two piezoelectric drive assemblies; the top plate is horizontally arranged above the bottom plate; the three leg upper adapter blocks are annularly mounted on the lower surface of the top plate; the bottom of each leg upper adapter block is symmetrically provided with two flexible hook hinges; one force sensor is correspondingly arranged on each flexible hook hinge; the flexible guide element is a hollow cylindrical structure; the flexible guide element upper cover is coaxially covered on the top end of the flexible guide element; the flexible guide element lower cover is coaxially covered on the bottom end of the flexible guide element; the corresponding flexible guide element lower cover of each flexible guide element is mounted on the top of one piezoelectric drive assembly, and the corresponding flexible guide element upper cover is connected with one flexible hook hinge.

[0009] In the piezoelectric active-passive hybrid vibration isolation platform, the three leg upper adapter blocks are concentric with the three leg lower adapter blocks, and the leg upper adapter blocks and the leg lower adapter blocks are staggered.

[0010] In the piezoelectric active-passive hybrid vibration isolation platform, the two piezoelectric drive assemblies on each leg lower adapter block are symmetrically and upwardly arranged; the included angle between the two piezoelectric drive assemblies corresponding to the same leg lower adapter block is 90°.

[0011] In the piezoelectric active-passive hybrid vibration isolation platform, the two flexible hook hinges on each leg upper adapter block are symmetrically and downwardly arranged; the included angle between the two flexible hook hinges corresponding to the leg upper adapter block is 90°.

[0012] In the piezoelectric active-passive hybrid vibration isolation platform, each piezoelectric drive assembly is coaxially opposite to one flexible hook hinge, so that a group of flexible guide element upper covers, flexible guide elements and flexible guide element lower covers are mounted between the corresponding piezoelectric drive assembly and the flexible hook hinge.

[0013] In the piezoelectric active-passive hybrid vibration isolation platform, the flexible guide element comprises a diaphragm spring, a mandrel, a shaft sleeve and a shell.

[0014] The shell is a hollow cylindrical structure; the mandrel is arranged at the axial direction of the shell; the shaft sleeve is sleeved on the outer wall of the mandrel; the diaphragm spring is sleeved on the outer wall of the mandrel; the flexible guide element upper cover is covered on the top opening of the shell; the flexible guide element lower cover is covered on the bottom opening of the shell; the top of the mandrel protrudes from the flexible guide element upper cover to be connected with the corresponding flexible hook hinge; the bottom of the flexible guide element lower cover is connected with the corresponding piezoelectric drive assembly.

[0015] In the piezoelectric active-passive hybrid vibration isolation platform, the piezoelectric drive assembly comprises a piezoelectric actuator column, a pre-tightening screw and a displacement amplification flexible shell.

[0016] The bottom of the displacement amplification flexible shell is connected with the corresponding lower adapter block of the supporting leg, the top of the displacement amplification flexible shell is connected with the corresponding flexible guide element, the piezoelectric actuator column is arranged axially and horizontally in the inner cavity of the displacement amplification flexible shell, and the pre-tightening screw extends from the side wall of the displacement amplification flexible shell.

[0017] In the piezoelectric active-passive hybrid vibration isolation platform, the vertical section of the displacement amplification flexible shell is an 8-face structure, the top and bottom centers of the displacement amplification flexible shell are horizontal plane structures, the two sides of the displacement amplification flexible shell are vertical plane structures, the horizontal plane of the top is connected with the two vertical planes through one inclined surface respectively, and the horizontal plane of the bottom is connected with the two vertical planes through one inclined surface respectively.

[0018] In the piezoelectric active-passive hybrid vibration isolation platform, the angle between the horizontal plane of the top and the corresponding inclined surface is 45°-135°, the angle between the horizontal plane of the bottom and the corresponding inclined surface is 45°-135°, and the deformation ratio is less than 1.

[0019] In the piezoelectric active-passive hybrid vibration isolation platform, when the piezoelectric actuator column is horizontally elongated, the horizontal extension of the side wall of the displacement amplification flexible shell is realized, the displacement amplification flexible shell is deformed, and the height of the displacement amplification flexible shell is reduced.

[0020] Compared with the prior art, the piezoelectric active-passive hybrid vibration isolation platform has the following beneficial effects:

[0021] (1) The piezoelectric active-passive hybrid vibration isolation platform can ensure sufficient force and displacement driving margin by adopting a piezoelectric active element to control low frequency and combining a displacement amplification flexible shell, and can stably inhibit the transmission of medium and high frequency vibration by adopting a spring as a passive element, so that vibration control can be realized in the full frequency band.

[0022] (2) The piezoelectric active-passive hybrid vibration isolation platform adopts a flexible structure to replace a traditional relative sliding or rotating motion pair, and the relative motion is provided by the elastic deformation of the flexible structure, so that the platform responds faster and moves more smoothly, and the precise control of the platform is effectively guaranteed.

[0023] (3) The piezoelectric active-passive hybrid vibration isolation platform adopts a flexible hinge to simplify the force transmission characteristics of each supporting leg, can realize independent control between the supporting legs, and reduces the complexity of the control algorithm. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a whole schematic view of the piezoelectric active-passive hybrid vibration isolation platform.

[0025] Figure 2 It is a schematic view of the flexible guide element and the piezoelectric driving assembly. DETAILED DESCRIPTION

[0026] The application will be further described in connection with the following examples.

[0027] The application provides a piezoelectric active-passive hybrid vibration isolation platform, which adopts flexible structures as linear motion pairs and rotation pairs to realize guiding and micro-rotation functions.

[0028] The piezoelectric active-passive hybrid vibration isolation platform comprises a top plate 1, flexible Hooke's hinges 2, three leg upper adapter blocks 3, a flexible guiding element upper cover 4, six flexible guiding elements 5, a force sensor 6, a flexible guiding element lower cover 7, piezoelectric driving assemblies 8, three leg lower adapter blocks 9 and a bottom plate 10. The bottom plate 10 is horizontally arranged in a plate shape; the three leg lower adapter blocks 9 are annularly arranged on the upper surface of the bottom plate 10; two piezoelectric driving assemblies 8 are symmetrically arranged on the top of each leg lower adapter block 9; the top plate 1 is horizontally arranged above the bottom plate 10; the three leg upper adapter blocks 3 are annularly arranged on the lower surface of the top plate 1; two flexible Hooke's hinges 2 are symmetrically arranged on the bottom of each leg upper adapter block 3; one force sensor 6 is arranged on each flexible Hooke's hinge 2; the flexible guiding element 5 is a hollow column structure; the flexible guiding element upper cover 4 is coaxially arranged on the top end of the flexible guiding element 5; the flexible guiding element lower cover 7 is coaxially arranged on the bottom end of the flexible guiding element 5; the corresponding flexible guiding element lower cover 7 of each flexible guiding element 5 is arranged on the top of one piezoelectric driving assembly 8, and the corresponding flexible guiding element upper cover 4 is connected with one flexible Hooke's hinge 2.

[0029] The piezoelectric driving assembly, the flexible Hooke's hinge, the flexible guiding element and the force sensor are connected in series to form a single leg of the vibration isolation platform; the multiple legs are connected in parallel, the top of the leg is connected with the top plate, and the bottom of the leg is connected with the bottom plate; the signal of the force sensor is used as feedback to adjust the working state of the piezoelectric driving assembly, thereby controlling the vibration transmissibility between the top plate and the bottom plate and the position of the top plate relative to the bottom plate.

[0030] In the application, the three leg upper adapter blocks 3 are concentric with the three leg lower adapter blocks 9, and the leg upper adapter blocks 3 and the leg lower adapter blocks 9 are staggered; the two piezoelectric driving assemblies 8 on each leg lower adapter block 9 are symmetrically and upwardly arranged at an angle; the angle between the two piezoelectric driving assemblies 8 corresponding to the same leg lower adapter block 9 is 90°; the two flexible Hooke's hinges 2 on each leg upper adapter block 3 are symmetrically and downwardly arranged at an angle; the angle between the two flexible Hooke's hinges 2 corresponding to the same leg upper adapter block 3 is 90°; each piezoelectric driving assembly 8 is coaxially opposite to one flexible Hooke's hinge 2, and a set of flexible guiding element upper covers 4, flexible guiding elements 5 and flexible guiding element lower covers 7 are arranged between the corresponding piezoelectric driving assembly 8 and the flexible Hooke's hinge 2.

[0031] As shown in Figure 2 The flexible guide element 5 includes a diaphragm spring 5-1, a mandrel 5-2, a sleeve 5-3, and a housing 5-4. The housing 5-4 is a hollow cylindrical structure; the mandrel 5-2 is arranged at the axial direction of the housing 5-4; the sleeve 5-3 is sleeved on the outer wall of the mandrel 5-2; the diaphragm spring 5-1 is sleeved on the outer wall of the mandrel 5-2; the flexible guide element upper cover 4 is covered on the top opening of the housing 5-4; the flexible guide element lower cover 7 is covered on the bottom opening of the housing 5-4; the top of the mandrel 5-2 protrudes from the flexible guide element upper cover 4 to realize the butt joint with the corresponding flexible hook hinge 2; the bottom of the flexible guide element lower cover 7 is butt jointed with the corresponding piezoelectric driving assembly 8.

[0032] The diaphragm spring 5-1 is in the form of a sheet as a whole, the inner ring is connected with the mandrel 5-2, and the outer ring is connected with the housing 5-4. The stiffness along the outer surface of the diaphragm spring is at least one order of magnitude lower than the stiffness along the inner surface of the diaphragm spring. Since the pair of diaphragm springs have a certain spacing along the mandrel axis direction, the pair of diaphragm springs are more conducive to resisting the torque around the vertical mandrel axis direction than the single diaphragm spring, thereby realizing the guiding function of the mandrel movement.

[0033] The entire leg can be divided into upper and lower parts with the pair of 5-1 as the boundary. The upper half is composed of a force sensor, a mandrel, a sleeve, and an inner ring of a pair of diaphragm springs. The lower half of the leg is composed of an outer ring of a diaphragm spring, an outer shell, a piezoelectric driving assembly, a flexible guide element upper cover, and a flexible guide element lower cover. The connection stiffness between the two parts in the direction along the mandrel axis is much lower than the connection stiffness in other directions. When the two parts move relative to each other, it can be approximately considered that they are connected by a low-stiffness spring, thereby forming a low-stiffness passive vibration isolation of the platform.

[0034] The piezoelectric driving assembly 8 includes a piezoelectric actuator column 8-1, a pre-tightening screw 8-2, and a displacement amplification flexible housing 8-3. The bottom of the displacement amplification flexible housing 8-3 is butt jointed with the corresponding leg lower adapter block 9; the top of the displacement amplification flexible housing 8-3 is butt jointed with the corresponding flexible guide element 5; the piezoelectric actuator column 8-1 is arranged axially and horizontally in the inner cavity of the displacement amplification flexible housing 8-3; the pre-tightening screw 8-2 extends from the side wall of the displacement amplification flexible housing 8-3; and the pre-tightening screw 8-2 is coaxially butt jointed with the piezoelectric actuator column 8-1 to apply a pre-tightening force to the piezoelectric actuator column 8-1.

[0035] The vertical section of the displacement amplification flexible shell 8-3 is a 8-polyhedral structure; the top and bottom center of the displacement amplification flexible shell 8-3 are horizontal plane structures; the two sides of the displacement amplification flexible shell 8-3 are vertical plane structures; the horizontal plane of the top is connected with the vertical plane of the two sides through one inclined plane respectively; the horizontal plane of the bottom is connected with the vertical plane of the two sides through one inclined plane respectively. The included angle between the horizontal plane of the top and the corresponding inclined plane is 45°-135°; the included angle between the horizontal plane of the bottom and the corresponding inclined plane is 45°-135°; the ratio of the deformation amount is less than 1.

[0036] When the piezoelectric actuator column 8-1 is horizontally elongated, the horizontal extrapolation of the side wall of the displacement amplification flexible shell 8-3 is realized, the displacement amplification flexible shell 8-3 is deformed, and the height of the displacement amplification flexible shell 8-3 is reduced.

[0037] The adjustment of the pre-tightening force of the piezoelectric actuator column 8-1 can be realized by rotating the pre-tightening screw 8-2. The output capacity of the piezoelectric driving assembly as a whole is closely related to the pre-tightening force. The greater the pre-tightening force is, the stronger the output capacity is. However, the maximum pre-tightening force is limited by the nominal output capacity of the piezoelectric actuator column.

[0038] The piezoelectric active element is adopted to control low frequency, the displacement amplification flexible shell is combined, sufficient force and displacement driving margin can be ensured, at the same time, the spring is adopted as a passive element to stably inhibit the transmission of medium and high frequency vibration, so that vibration control can be realized in the full frequency band.

[0039] The flexible structure is adopted to replace the traditional relative sliding or rotating movement pair, the relative movement is provided by the elastic deformation of the flexible structure, so that the platform responds faster and moves more smoothly, and the precise control of the platform is effectively ensured.

[0040] The flexible hinge is adopted to simplify the force transmission characteristics of each leg, independent control between the legs can be realized, and the complexity of the control algorithm is reduced.

[0041] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, belongs to the protection scope of the technical solutions of the present application.

Claims

1. A piezoelectric hybrid active-passive vibration isolation platform, characterized in that: It includes a top plate (1), a flexible Hooke hinge (2), three upper connecting blocks for the legs (3), a flexible guide element cover (4), six flexible guide elements (5), a force sensor (6), a flexible guide element cover (7), a piezoelectric drive assembly (8), three lower connecting blocks for the legs (9), and a base plate (10). The base plate (10) is a horizontally placed plate structure; three lower leg adapter blocks (9) are arranged in a ring on the upper surface of the base plate (10); two piezoelectric drive components (8) are symmetrically arranged on the top of each lower leg adapter block (9); the top plate (1) is horizontally positioned above the base plate (10); three upper leg adapter blocks (3) are arranged in a ring on the lower surface of the top plate (1); two flexible Hooke hinges (2) are symmetrically arranged at the bottom of each upper leg adapter block (3); each flexible Hooke hinge (2) A force sensor (6) is set on the upper part; the flexible guide element (5) is a hollow column structure; the upper cover (4) of the flexible guide element is coaxially mounted on the top of the flexible guide element (5); the lower cover (7) of the flexible guide element is coaxially mounted on the bottom of the flexible guide element (5); the lower cover (7) of the flexible guide element corresponding to each flexible guide element (5) is mounted on the top of a piezoelectric drive assembly (8), and the upper cover (4) of the corresponding flexible guide element is connected to a flexible Hooke hinge (2).

2. The piezoelectric active-passive hybrid vibration isolation platform according to claim 1, characterized in that: The three upper adapter blocks (3) of the outriggers form a ring and are concentric with the three lower adapter blocks (9) of the outriggers, and the upper adapter blocks (3) and the lower adapter blocks (9) of the outriggers are staggered.

3. The piezoelectric active-passive hybrid vibration isolation platform according to claim 2, characterized in that: The two piezoelectric drive components (8) on each leg under adapter block (9) are symmetrically tilted upwards; the included angle between the two piezoelectric drive components (8) corresponding to the same leg under adapter block (9) is 90°.

4. The piezoelectric active-passive hybrid vibration isolation platform according to claim 3, characterized in that: The two flexible Hooke hinges (2) on the adapter block (3) of each leg are symmetrically and clearly set downwards; the included angle between the two corresponding flexible Hooke hinges (2) on the adapter block (3) of the leg is 90°.

5. The piezoelectric active-passive hybrid vibration isolation platform according to claim 4, characterized in that: Each piezoelectric drive assembly (8) is coaxially opposite to a flexible Hooke hinge (2), thereby enabling a set of flexible guide element upper cover (4), flexible guide element (5), and flexible guide element lower cover (7) to be installed between the corresponding piezoelectric drive assembly (8) and the flexible Hooke hinge (2).

6. The piezoelectric active-passive hybrid vibration isolation platform according to claim 5, characterized in that: The flexible guiding element (5) includes a diaphragm spring (5-1), a spindle (5-2), a bushing (5-3), and a housing (5-4); The housing (5-4) is a hollow cylindrical structure; the spindle (5-2) is located in the axial direction of the housing (5-4); the bushing (5-3) is fitted on the outer wall of the spindle (5-2); the diaphragm spring (5-1) is fitted on the outer wall of the spindle (5-2); the upper cover (4) of the flexible guide element is installed at the top opening of the housing (5-4); the lower cover (7) of the flexible guide element is installed at the bottom opening of the housing (5-4); the top of the spindle (5-2) extends out of the upper cover (4) of the flexible guide element to achieve docking with the corresponding flexible Hooke hinge (2); the bottom of the lower cover (7) of the flexible guide element docks with the corresponding piezoelectric drive assembly (8).

7. The piezoelectric active-passive hybrid vibration isolation platform according to claim 5, characterized in that: The piezoelectric drive assembly (8) includes a piezoelectric actuating column (8-1), a preload screw (8-2), and a displacement amplification flexible housing (8-3); The bottom of the displacement amplification flexible housing (8-3) is connected to the corresponding lower adapter block (9) of the support leg; the top of the displacement amplification flexible housing (8-3) is connected to the corresponding flexible guide element (5); the piezoelectric actuator (8-1) is axially and horizontally arranged in the inner cavity of the displacement amplification flexible housing (8-3); the preload screw (8-2) extends from the side wall of the displacement amplification flexible housing (8-3); the preload screw (8-2) is coaxially connected with the piezoelectric actuator (8-1) to apply a preload force to the piezoelectric actuator (8-1).

8. The piezoelectric active-passive hybrid vibration isolation platform according to claim 7, characterized in that: The vertical cross-section of the displacement amplification flexible shell (8-3) is an octahedral structure; the top and bottom centers of the displacement amplification flexible shell (8-3) are both horizontal plane structures; both sides of the displacement amplification flexible shell (8-3) are vertical plane structures; the horizontal plane at the top is connected to the vertical planes on both sides by an inclined plane; the horizontal plane at the bottom is connected to the vertical planes on both sides by an inclined plane.

9. The piezoelectric active-passive hybrid vibration isolation platform according to claim 7, characterized in that: The angle between the horizontal plane at the top and the corresponding inclined plane is 45°-135°; the angle between the horizontal plane at the bottom and the corresponding inclined plane is 45°-135°; the ratio of deformation is less than 1.

10. The piezoelectric active-passive hybrid vibration isolation platform according to claim 7, characterized in that: When the piezoelectric actuator (8-1) extends horizontally, it pushes the side wall of the displacement amplification flexible shell (8-3) horizontally outward, causing the displacement amplification flexible shell (8-3) to deform and reduce its height.

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