Quasi-zero stiffness vibration isolation and pointing integrated platform

Abstract

The application discloses a quasi-zero stiffness vibration isolation and pointing integrated platform, which comprises a base platform, a working platform and a plurality of leg mechanisms with quasi-zero stiffness characteristics arranged between the base platform and the working platform, one end of the leg mechanism is connected with the base platform through a two-axis flexible hinge, and the other end of the leg mechanism is connected with the working platform through a three-axis flexible hinge, so that spatial six-degree-of-freedom wide-band vibration isolation and pointing control are realized. The application utilizes linear and nonlinear positive stiffness structures to compensate for negative stiffness structure design, designs passive quasi-zero stiffness structures and active quasi-zero stiffness structures, composites the passive quasi-zero stiffness structures and the active quasi-zero stiffness structures to form quasi-zero stiffness legs, the quasi-zero stiffness legs can bear large loads, the ideal balance position adjustment of the passive quasi-zero stiffness structures can be realized by translating the negative stiffness structures of the passive quasi-zero stiffness structures, the ideal balance position adjustment of the active quasi-zero stiffness structures can be realized by translating the nonlinear positive stiffness structures of the active quasi-zero stiffness structures and adjusting the current size, so that the leg length is adjustable, and the quasi-zero stiffness legs have the pointing function.

Description

Technical Field

[0001] This invention relates to a technology in the field of vibration isolation, specifically a quasi-zero stiffness vibration isolation and pointing integrated platform. Background Technology

[0002] Sensitive payloads on spacecraft such as remote sensing satellites and deep space telescopes face increasingly demanding operating environments. Single vibration control or attitude control methods are no longer sufficient to meet the ever-improving performance requirements of these high-precision devices. Therefore, there is a need to develop vibration isolation and pointing coordination control technologies that integrate vibration isolation and motion compensation methods. Traditional vibration isolation and pointing coordination control methods connect the isolation system and the pointing system in series and control them independently. This results in complex structures, high costs, large size and weight, and the isolation bandwidth and pointing control margin are mutually restrictive, affecting both isolation and pointing performance. Existing integrated vibration isolation and pointing platforms are mostly based on precision positioning or active vibration control principles, which have drawbacks such as high cost, high energy consumption for adjustment, small stroke, low load capacity, limited attitude adjustment range, and insufficient suppression of mid- and high-frequency vibrations. Quasi-zero stiffness vibration isolation methods balance high load capacity and wide isolation bandwidth. Researching quasi-zero stiffness integrated vibration isolation and pointing control methods can broaden the dynamic isolation bandwidth, reduce the active control bandwidth, lower energy consumption, resolve the contradiction between the isolation bandwidth and pointing control margin, and improve both isolation and pointing performance. However, there are still many limitations to the current integrated design of quasi-zero stiffness vibration isolation control and pointing control. For example, the existing methods for achieving quasi-zero stiffness have strict design requirements, the balance position cannot be adjusted, and the load matching requirements are high, making it difficult to apply quasi-zero stiffness vibration isolation methods to engineering fields that require leveling and attitude control. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies that lack vibration isolation and pointing functions by proposing a quasi-zero stiffness integrated vibration isolation and pointing platform. It utilizes linear and nonlinear positive stiffness structures to compensate for negative stiffness structures, designing both passive and active quasi-zero stiffness structures. These passive and active quasi-zero stiffness structures are combined to form quasi-zero stiffness legs capable of withstanding large loads. The ideal equilibrium position of the passive quasi-zero stiffness structure can be adjusted by translating the negative stiffness structure, and the ideal equilibrium position of the active quasi-zero stiffness structure can be adjusted by translating the nonlinear positive stiffness structure and adjusting the energizing current. This allows for adjustable leg length and pointing functionality.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to a quasi-zero stiffness vibration isolation and pointing integrated platform, comprising: a base platform, a working platform, and several support leg mechanisms with quasi-zero stiffness characteristics disposed between the two, wherein: one end of the support leg mechanism is connected to the base platform via a two-axis flexible hinge, and the other end of the support leg mechanism is connected to the working platform via a three-axis flexible hinge, thereby realizing spatial six-degree-of-freedom broadband vibration isolation and pointing control.

[0006] Technical effect

[0007] This invention utilizes a nonlinear positive stiffness structure to compensate for a negative stiffness structure to achieve an active quasi-zero stiffness structure. The active quasi-zero stiffness structure and the passive quasi-zero stiffness structure are combined to form a multi-degree-of-freedom vibration isolation platform leg. The negative stiffness structure of the passive quasi-zero stiffness structure is driven to achieve the ideal equilibrium position of the passive quasi-zero stiffness structure. The nonlinear positive stiffness structure of the active quasi-zero stiffness structure is driven, and the magnitude of the current is adjusted to regulate the ideal equilibrium position of the active quasi-zero stiffness structure.

[0008] Compared with existing technologies, the passive quasi-zero stiffness structure of this invention can withstand large loads, while the rated load of the active quasi-zero stiffness vibration isolation structure is proportional to the current. The passive and active quasi-zero stiffness structures are combined to form the platform's quasi-zero stiffness legs. By translating the negative stiffness structure of the passive quasi-zero stiffness structure and the nonlinear positive stiffness structure of the active quasi-zero stiffness structure, the magnitude of the current is adjusted to achieve the platform's pointing function, while maintaining the quasi-zero stiffness vibration isolation characteristics. This invention combines the advantages of quasi-zero stiffness through dynamic vibration isolation, integrating quasi-zero stiffness vibration isolation and pointing into a single design. It has a large load-bearing capacity, can broaden the through dynamic vibration isolation frequency band, reduce the active control bandwidth, reduce energy consumption, resolve the contradiction between the vibration isolation frequency band and the pointing control margin, and improve both vibration isolation and pointing performance. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of the present invention;

[0010] Figure 2 A schematic diagram of the overall structure of the vibration isolation table support legs;

[0011] Figure 3 This is a sectional view of the support leg of the vibration isolation table;

[0012] Figure 4 This is a force-displacement relationship diagram of the passive quasi-zero stiffness structure of the present invention;

[0013] Figure 5 This is a force-displacement relationship diagram of the active quasi-zero stiffness structure of the present invention;

[0014] Figure 6 This is a force-displacement relationship diagram of the active quasi-zero stiffness structure of the present invention under different currents;

[0015] Figure 7 This is a diagram showing the ideal equilibrium position adjustment of the passive quasi-zero stiffness structure of the present invention.

[0016] Figure 8 This is a diagram showing the ideal equilibrium position adjustment of the active quasi-zero stiffness structure of the present invention.

[0017] In the diagram: 1. Base platform; 2. Two-axis flexible hinge; 3. Support leg; 4. Three-axis flexible hinge; 5. Work platform; 301. Motor cover; 302. Base; 303. Lower bracket; 304. Adapter flange; 305. Conical coil seat; 306. Upper cover; 307. Motor.

[0018] 308 First bolt, 309 Second bolt, 310 Third bolt, 311 Ball bearing, 312 Fourth bolt, 313 Cantilever beam,

[0019] 314 Fifth bolt, 315 Clamping block, 316 Sixth bolt, 317 Seventh bolt, 318 Eighth bolt, 319 First spring leaf.

[0020] 320 First nut, 321 Guide rod, 322 Second nut, 323 Third nut, 324 First permanent magnet, 325 Conical coil, 326 Ninth bolt, 327 Fourth nut, 328 Cantilever beam fixing seat, 329 Fifth nut, 330 Second permanent magnet, 331 Sixth nut, 332 Cylindrical coil, 333 Tenth bolt, 334 Second spring, 335 Protrusion, 336 Support plate, 337 Eleventh bolt. Detailed Implementation

[0021] like Figure 1 As shown in the figure, this embodiment relates to a quasi-zero stiffness vibration isolation and pointing integrated platform, which includes: a base platform 1, a working platform 5, and several legs 3 with quasi-zero stiffness characteristics disposed between the two. One end of the leg 3 is connected to the base platform 1 by a two-axis flexible hinge 2, and the other end of the leg mechanism is connected to the working platform by a three-axis flexible hinge 4, thereby realizing spatial six-degree-of-freedom broadband vibration isolation and pointing control.

[0022] like Figure 2 and Figure 3 As shown, the outrigger 3 includes: an outer frame, a rotating mechanism disposed inside it, and a passive quasi-zero stiffness structure and an active quasi-zero stiffness structure disposed on the rotating mechanism.

[0023] The rotating mechanism includes a motor 307, a support plate 336, a protrusion 335, and a guide rod 321 connected in sequence. The guide rod 321 is located at the central axis of the outer frame. The motor 307 drives the support plate 336 and the protrusion 335 to rotate the guide rod 321 in sequence. The protrusion 335 fits into the support plate 336 through the central hole and is fixedly connected by bolts. The support plate 336 is connected to the output shaft of the motor 307. The motor 307 is fixedly connected to the base 302 by bolts.

[0024] The motor 307 is preferably a linear stepper motor.

[0025] The passive quasi-zero stiffness structure includes: a first spring 319, a second spring 334, a cantilever beam 313, and a cantilever beam fixing seat 328, wherein: the first spring 319 and the second spring 334 are respectively disposed at the upper and lower ends of the guide rod 321, and the cantilever beam 313 is fixedly disposed on the guide rod 321 through the cantilever beam fixing seat 328.

[0026] The cantilever beam fixing seat 328 is fitted onto the guide rod 321 through the central hole, with one side pressed against the shaft shoulder and the other side pressed by a nut; one end of the cantilever beam 313 is fixed to the cantilever beam fixing seat 328 by a pressure block and bolts, and the other end is in contact with the surface of the protrusion 335 through a ball bearing 311.

[0027] The protrusion 335 has an incomplete spherical shape. When under load, the cantilever beam 313 will flex and slide on the surface of the protrusion 335, changing the vertical component of the restoring force and providing bistable negative stiffness.

[0028] The first spring 319 is fixedly mounted on the upper end cover 306 by bolts, and the middle of the first spring 319 is clamped and fixedly connected to the guide rod 321 by nuts on the upper and lower sides.

[0029] The second spring 334 is fixed inside the protrusion 335 by bolts, with its upper side close to the lower end of the guide rod 321, and its lower side is pressed by a bolt screwed into the central threaded hole.

[0030] The first reed 319 and the second reed 334 have linear stiffness.

[0031] The outer frame includes, from bottom to top, a base 302, a motor cover 301, a lower bracket 303, an adapter flange 304, a tapered coil seat 305, and an upper cover 306.

[0032] The upper and lower surfaces of the base 302 are respectively provided with cylindrical flanges, and the motor cover 301 is provided with a central hole, which fits with the lower flange of the base 302 and is fixedly connected by bolts.

[0033] The lower support 303 is a cylindrical structure that fits into the flange of the base 302 and is fixedly connected.

[0034] The lower end of the adapter flange 304 is fitted into the lower bracket 303, and the upper end is fitted into the conical coil seat 305. The flange is fixedly connected to the lower bracket 303 and the conical coil seat 305 by bolts.

[0035] The tapered bearing housing 305 has a flange on its upper surface.

[0036] The upper end is provided with a groove of matching shape, and the upper end cover 306 fits into the conical coil seat 305 and is fixedly connected.

[0037] The active quasi-zero stiffness structure includes: a conical coil 325, a cylindrical coil 332, a first permanent magnet 324, and a second permanent magnet 330. The conical coil 325 is fixedly mounted in the outer frame via a conical coil seat 305. The first permanent magnet 324 and the second permanent magnet 330 are sequentially sleeved on the guide rod 321. The cylindrical coil 332 is fixedly mounted in the protrusion 335 and faces the first permanent magnet 324. The second permanent magnet 330 and the conical coil 325 are nested and mutually repulsive, providing monostable negative stiffness. The first permanent magnet 324 and the cylindrical coil 332 are arranged end-to-end and mutually repulsive, providing nonlinear gradually hardening positive stiffness.

[0038] The tapered coil holder 305 is provided with a tapered hole, and the tapered coil 325 is embedded in the tapered coil holder 305.

[0039] The second permanent magnet 330 is fitted with a shoulder on one side and nested with a tapered coil 325 on the other side.

[0040] The first permanent magnet 324 clamps the fiber by a limiting nut set on the guide rod 321.

[0041] The conical coil 325 and cylindrical coil 332 are powered independently. The monostable negative stiffness and nonlinear gradually hardening positive stiffness are proportional to the coil current. While maintaining the current ratio of the conical coil 325 and cylindrical coil 332, changing the current can adjust the rated load without causing a change in the quasi-zero stiffness equilibrium position.

[0042] Apart from the permanent magnet, the other components of the vibration isolation table are preferably made of weakly magnetic materials.

[0043] like Figure 3 As shown, when under load, the cantilever beam 313 will flex and slide on the surface of the protrusion 335, changing the vertical component of the restoring force and providing bistable negative stiffness; the first spring 319 and the second spring 334 have linear stiffness.

[0044] In the active quasi-zero stiffness structure, the first permanent magnet 324 and the conical coil 325 are nested and repel each other, providing monostable negative stiffness; the second permanent magnet 330 and the cylindrical coil 332 are arranged end to end, and they repel each other, providing nonlinear gradually hardening positive stiffness.

[0045] In the active quasi-zero stiffness structure, the conical coil 325 and the cylindrical coil 332 are powered independently. The monostable negative stiffness and the nonlinear gradually hardening positive stiffness are proportional to the coil current. While maintaining the current ratio of the conical coil 325 and the cylindrical coil 332, changing the current can adjust the rated load without causing a change in the quasi-zero stiffness equilibrium position.

[0046] In the passive quasi-zero stiffness structure, when the driving motor 307 is driven, the protrusion 335 is translated, the passive quasi-zero stiffness structure bistable negative stiffness structure is translated, and the ideal equilibrium position of quasi-zero stiffness is translated.

[0047] In the active quasi-zero stiffness structure, when the driving motor 307 is driven, the cylindrical coil 332 is translated, and the nonlinear positive stiffness structure of the active quasi-zero stiffness structure is translated. At the same time, the current flowing through the conical coil 325 and the cylindrical coil 332 is changed, and the positive and negative stiffness are scaled, so that the ideal equilibrium position of the active quasi-zero stiffness structure can be translated.

[0048] The passive quasi-zero stiffness structure and the active quasi-zero stiffness structure always maintain the same ideal balance position. The drive motor 307 can change the ideal balance position, causing the length of the support leg 3 to change, and the drive platform can complete the pointing function while maintaining the quasi-zero stiffness characteristics.

[0049] like Figures 4-8 As shown, when the motor is driven in a half-step drive mode using pulse signal commands, the convex blocks can be translated. The passive quasi-zero stiffness structure and the bistable negative stiffness structure are translated, and the ideal equilibrium position of the quasi-zero stiffness is also translated. When the motor is driven in a half-step drive mode using pulse signal commands, the cylindrical coil can be translated. The active quasi-zero stiffness structure and the nonlinear positive stiffness structure are translated. At the same time, the current flowing through the conical coil and the cylindrical coil is changed, and the positive and negative stiffness are scaled, which can translate the ideal equilibrium position of the active quasi-zero stiffness structure. When the motor is driven in a half-step drive mode using pulse signal commands, the ideal equilibrium positions of the passive quasi-zero stiffness structure and the active quasi-zero stiffness structure always coincide and change in the same way with the motor drive, resulting in a change in the length of the support legs. The drive platform completes the pointing function while maintaining the quasi-zero stiffness characteristics.

[0050] Compared with existing technologies, this device, compared with traditional vibration isolation and pointing series control platforms or integrated vibration isolation and pointing platforms based on precision positioning principles, combines the advantages of quasi-zero stiffness through dynamic vibration isolation. It combines passive quasi-zero stiffness structures with active quasi-zero stiffness structures to achieve integrated design of quasi-zero stiffness and pointing. This can broaden the passing dynamic vibration isolation frequency band, reduce the active control bandwidth, reduce energy consumption, resolve the contradiction between vibration isolation frequency band and pointing control margin, and improve vibration isolation and pointing performance.

[0051] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A quasi-zero stiffness vibration isolation and pointing integrated platform, characterized in that, include: The base platform, the working platform, and several outrigger mechanisms with quasi-zero stiffness characteristics are set between the two. One end of the outrigger mechanism is connected to the base platform through a two-axis flexible hinge, and the other end of the outrigger mechanism is connected to the working platform through a three-axis flexible hinge, thereby realizing spatial six-degree-of-freedom broadband vibration isolation and directional control. The outrigger includes: an outer frame, a rotating mechanism disposed therein, and a passive quasi-zero stiffness structure and an active quasi-zero stiffness structure disposed on the rotating mechanism; The rotating mechanism includes a motor, a support plate, a protrusion, and a guide rod connected in sequence. The guide rod is located at the central axis of the outer frame. The motor drives the support plate and the protrusion to rotate in sequence. The protrusion fits into the support plate through the central hole and is fixedly connected by bolts. The support plate is connected to the output shaft of the motor. The motor is fixedly connected to the base by bolts. The active quasi-zero stiffness structure includes: a conical coil, a cylindrical coil, a first permanent magnet, and a second permanent magnet. The conical coil is fixedly mounted within the outer frame via a conical coil seat. The first and second permanent magnets are sequentially sleeved on the guide rod. The cylindrical coil is fixedly mounted within the protrusion and faces the first permanent magnet. The second permanent magnet and the conical coil are nested together and repel each other, providing monostable negative stiffness. The first permanent magnet and the cylindrical coil are arranged end-to-end and repel each other, providing nonlinear gradually hardening positive stiffness.

2. The quasi-zero stiffness vibration isolation and pointing integrated platform according to claim 1, characterized in that, The passive quasi-zero stiffness structure includes: a first spring, a second spring, a cantilever beam, and a cantilever beam fixing seat, wherein: the first spring and the second spring are respectively disposed at the upper and lower ends of the guide rod, and the cantilever beam is fixedly disposed on the guide rod by the cantilever beam fixing seat.

3. The quasi-zero stiffness vibration isolation and pointing integrated platform according to claim 2, characterized in that, The cantilever beam fixing seat is fitted onto the guide rod through the central hole, with one side pressed against the shaft shoulder and the other side pressed by a nut; one end of the cantilever beam is fixed to the cantilever beam fixing seat by a pressure block and bolts, and the other end is in contact with the surface of the protrusion through a ball bearing; The first spring is fixedly mounted on the upper end cover by bolts, and the middle of the first spring is clamped and fixedly connected to the guide rod by nuts on the upper and lower sides. The second spring is fixed inside the protrusion by bolts, with its upper side close to the lower end of the guide rod, and its lower side is pressed by bolts screwed into the central threaded hole.

4. The quasi-zero stiffness vibration isolation and pointing integrated platform according to claim 2, characterized in that, The first and second springs have linear stiffness, and the corresponding protrusion has an incomplete spherical shape. When under load, the cantilever beam will flex and slide on the surface of the protrusion, changing the vertical component of the restoring force and providing bistable negative stiffness.

5. The quasi-zero stiffness vibration isolation and pointing integrated platform according to claim 1, characterized in that, The outer frame includes, from bottom to top, a base, a motor cover, a lower bracket, an adapter flange, a tapered coil seat, and an upper cover.

6. The quasi-zero stiffness vibration isolation and pointing integrated platform according to claim 5, characterized in that, The upper and lower surfaces of the base are respectively provided with cylindrical flanges, and the motor cover is provided with a central hole, which fits into the lower flange of the base and is fixedly connected by bolts; The lower support is a cylindrical structure that fits into the flange on the base and is fixedly connected. The lower end of the adapter flange fits into the lower bracket, and the upper end fits into the tapered coil seat. The adapter flange is then fixedly connected to the lower bracket and the tapered coil seat by bolts.

7. The quasi-zero stiffness vibration isolation and pointing integrated platform according to claim 1, characterized in that, The conical coil holder is provided with a conical hole, and the conical coil is embedded in the conical coil holder; One side of the second permanent magnet is fitted with the shoulder of the shaft, and the other side is nested with the tapered coil; The first permanent magnet clamps the fiber by a limiting nut set on the guide rod.

8. The quasi-zero stiffness vibration isolation and pointing integrated platform according to claim 1, characterized in that, The conical coil and cylindrical coil are powered independently. The monostable negative stiffness and nonlinear gradually hardening positive stiffness are proportional to the coil current. While maintaining the current ratio of the conical coil and cylindrical coil, changing the current can adjust the rated load without causing a change in the quasi-zero stiffness equilibrium position. In the active quasi-zero stiffness structure, the first permanent magnet and the conical coil are nested and repel each other, providing monostable negative stiffness; the second permanent magnet and the cylindrical coil are arranged end to end, and they repel each other, providing nonlinear gradually hardening positive stiffness.

9. The quasi-zero stiffness vibration isolation and pointing integrated platform according to any one of claims 1-8, characterized in that, When the motor is driven in a half-step drive mode using pulse signal commands, the convex blocks can be translated. The passive quasi-zero stiffness structure and the bistable negative stiffness structure can be translated to achieve the ideal equilibrium position of the quasi-zero stiffness. When the motor is driven in a half-step drive mode using pulse signal commands, the cylindrical coils can be translated. The active quasi-zero stiffness structure and the nonlinear positive stiffness structure can be translated to achieve the ideal equilibrium position of the active quasi-zero stiffness structure. At the same time, the current flowing through the conical coil and the cylindrical coil is changed to scale the positive and negative stiffness, thereby translating the ideal equilibrium position of the active quasi-zero stiffness structure. When the motor is driven in a half-step drive mode using pulse signal commands, the ideal balance positions of the passive quasi-zero stiffness structure and the active quasi-zero stiffness structure always coincide and change in the same way as the motor is driven, resulting in a change in the length of the outriggers. The drive platform completes the pointing function while maintaining the quasi-zero stiffness characteristics.

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