A direct-drive large-stroke precision rotating platform

Abstract

The present invention relates to a direct-drive large-stroke precision rotating platform, comprising: a base; a flexure hinge bearing, including a flexure hinge, a drive end, a stator and a rotor, wherein the stator is fixed on the base, and the drive end is connected to the flexure hinge and extends outside the flexure hinge; a load carrier, fixedly connected to the rotor and used for connecting the flexure hinge bearing and an end effector; a pre-tightening spring, one end of which is fixed to the base and the other end of which is connected to the drive end; and a driver, disposed at the end of the drive end, one end of the driver is fixed on a driver bracket and thus fixed to the base, and the other end is fixed to or in contact with the drive end. The present invention greatly increases the stroke of the precision rotating platform, reduces the material stress in deformation, and extends the service life of the device; the precision rotating platform provided by the present invention requires a lower driving force and has a smaller requirement for the thrust of the driver; in the present invention, the driver is externally disposed, effectively reducing the adverse effects of the heat generation and vibration of the driver on the end effector.

Description

Technical Field

[0001] The present invention relates to the field of precision motion positioning, and in particular, to a direct-drive large-stroke precision rotating platform. Background Art

[0002] Precision rotation, as a typical motion mode in precision motion positioning, has important applications in the fields of optical scanning, medical cell operation, microfabrication, and precision measurement. Generally speaking, a precision rotating platform converts the linear motion of a driver into the required rotational motion at the end through a specifically designed mechanism, so as to achieve motion output or carrier control.

[0003] At present, precision rotating platforms have many defects, which are specifically as follows:

[0004] First, for a precision rotating platform that can rotate a full circle, a piezoelectric ceramic driver is generally used. Using the stick-slip or inchworm driving principle, the mover in the platform is indirectly driven to rotate a full circle. Due to limitations in principle, the resolution of this mode is unstable, and the wear between the mover and the stator is relatively large. After long-term use, the motion precision drops significantly;

[0005] Second, for a platform that can achieve continuous rotational motion or positioning within a fixed range, the driver directly drives the mover to rotate. When the driver is a piezoelectric ceramic or a voice coil motor, the platform can achieve an infinitesimal motion resolution. However, currently, such platforms are limited by the structural design. The structural stress and deformation are basically in the same direction, and only rely on the small elastic deformation of the material, so the stroke is small, and it is difficult to meet the increasingly common need for large-stroke motion.

[0006] Third, for a rotating platform using a flexible hinge structure as a transmission or deformation mechanism, usually to ensure the installation area of the rotating table, the hinge structure is small. Therefore, it is more sensitive to the manufacturing error and symmetry of the hinge, which is likely to cause the rotation center to drift. In addition, such platforms often set the driver near the rotation center or the hinge position, which is likely to generate in-plane parasitic translation and have an adverse effect on the precision rotation accuracy. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the present invention provides a direct-drive large-stroke precision rotating platform. The core structure is highly centrosymmetric. The platform can achieve precision rotational motion or positioning, and the mover has a large installation area. The part structure is easy to process, and the number of parts is small and easy to assemble, which is conducive to controlling the machining and assembly errors, thereby obtaining the stability of long-term motion.

[0008] The technical solution provided by the present invention is as follows:

[0009] A direct-drive large-stroke precision rotating platform, the rotating platform comprising:

[0010] A base;

[0011] A flexible hinge bearing comprises a flexible hinge, a driving end, a stator and a mover, wherein the stator is fixed on a base, and the driving end is connected to the center of the flexible hinge bearing and extends out of the flexible hinge;

[0012] A carrier, fixedly connected to the mover, and used to connect the flexible hinge bearing and the end-actuator components;

[0013] A preload spring, one end of which is connected to the spring bracket and then fixed to the base, and the other end of which is connected to the driving end, for preload and providing restoring force; and

[0014] The driver is placed at the end of the driving end, one end of the driver is fixed on the driver bracket and then fixed to the base, and the other end is fixed to or in contact with the driving end.

[0015] Furthermore, the end-effector is an optical reflector.

[0016] Furthermore, the driver is a linear driver.

[0017] Furthermore, the linear drive is a voice coil motor, a piezoelectric ceramic or a pneumatic drive.

[0018] Furthermore, the mover and the stator are connected through the flexible hinges, which are divided into eight groups and are centrally symmetrical. Each group of hinges is composed of three leaf spring-type flexible hinges connected in series, which greatly increases the flexibility of the bearing, reduces material stress, and greatly improves the movement stroke of the flexible bearing.

[0019] Furthermore, the bottom of the carrier protrudes and is connected to the mover without affecting the deformation and movement of the flexible hinge, and the end-actuator connected thereto is an optical reflector, a light source or a manipulator.

[0020] Furthermore, the preload spring is composed of a tension spring, a tension spring hook, and a tension spring bracket. The tension spring hook is connected to the driving end of the flexible hinge bearing through a thread and is further locked and fixed with a nut. The tension spring bracket is fixed to the base by bolts. One end of the tension spring is connected to a screw rod with a through hole at one end. The screw rod can move axially in the through hole of the tension spring bracket and is fixed in position by a nut. Adjusting the front and rear position of the screw rod can adjust the initial tension of the tension spring, that is, adjust the initial preload force on the driver.

[0021] Furthermore, a semicircular ball head is provided at the front end of the driver, and the semicircular ball head always maintains point contact with the end of the driving end, and the driver is fixed on the base through a driver bracket.

[0022] In the direct-drive large-stroke precision rotation platform of the present invention, the linear driver directly drives the end of the driving end of the flexible hinge bearing. Due to the constraint of the symmetric hinge structure, the moving part of the flexible hinge bearing, the carrier and the optical mirror thereon generate a rotational motion around the bearing axis. The preloading spring ensures that the end of the driver is always in contact with the end of the driving end of the flexible hinge bearing, achieving stable and precise driving.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. By designing a new type of flexible hinge bearing with a symmetric structure and low stiffness, the present invention greatly increases the stroke of the flexible bearing, i.e., the precision rotation platform, reduces the material stress during deformation, and extends the service life of the device.

[0025] 2. The present invention directly drives the mover through a linear driver, having stable and precise resolution.

[0026] 3. The precision rotation platform provided by the present invention requires lower driving force, has lower requirements for the thrust of the driver, and can be applied to various linear drivers such as voice coil motors, piezoelectric ceramics, and pneumatic drivers.

[0027] 4. The flexible hinge bearing in the present invention has a mover that is only slightly smaller than the stator, i.e., has a large installation area, and has stronger expandability for subsequent actuating components.

[0028] 5. In the present invention, the driver is externally placed, far from the core moving part, the flexible hinge bearing, effectively reducing the adverse effects of the heat and vibration of the driver on the actuating components, and at the same time greatly weakening the parasitic translation in the plane and ensuring the stability of the rotation center. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a direct-drive large-stroke precision rotation platform of the present invention;

[0030] Figure 2 It is an exploded view of the structure of a direct-drive large-stroke precision rotation platform of the present invention;

[0031] Figure 3 It is a front view of the structure of a direct-drive large-stroke precision rotation platform of the present invention;

[0032] Figure 4 It is a side view of the structure of a direct-drive large-stroke precision rotation platform of the present invention;

[0033] Figure 5 It is a top view of the structure of a direct-drive large-stroke precision rotation platform of the present invention;

[0034] Figure 6 It is a schematic diagram of the flexible hinge of a direct-drive large-stroke precision rotation platform of the present invention;

[0035] Figure 7 Schematic diagram of the structure of a piezoelectric ceramic direct drive large stroke precision rotation platform of the present invention;

[0036] Figure 8 Exploded view of the structure of a piezoelectric ceramic direct drive large stroke precision rotation platform of the present invention;

[0037] Figure 9 Top view of the structure of a piezoelectric ceramic direct drive large stroke precision rotation platform of the present invention;

[0038] Figure 10 Schematic diagram of the integral flexible hinge of a piezoelectric ceramic direct drive large stroke precision rotation platform of the present invention.

[0039] Reference numerals: 1 - base; 2 - flexible hinge bearing; 3 - carrier; 4 - optical mirror; 5 - tension spring hook; 6 - tension spring; 7 - tension spring bracket; 8 - driver; 9 - driver bracket; 10 - flexible lever type amplification mechanism; 11 - piezoelectric ceramic driver; 12 - piezoelectric ceramic driver bracket. Detailed implementation manners

[0040] The following describes the detailed implementation manners of the present invention with reference to the accompanying drawings.

[0041] As Figures 1 - 6 shown, a direct drive large stroke precision rotation platform in a specific embodiment of the present invention includes: a base 1, a flexible hinge bearing 2, a carrier 3, a pre - tension spring, and a driver 8; wherein, the flexible hinge bearing 2 includes a flexible hinge, a driving end, a stator and a rotor, the stator is fixed on the base 1, and the driving end is connected to the flexible hinge and extends outside the flexible hinge; the carrier 3 is fixedly connected to the rotor and is used to connect the flexible hinge bearing and the optical mirror 4; one end of the pre - tension spring is fixed to the base, and the other end is connected to the driving end, which is used for pre - tensioning and providing a restoring force; the driver 8 is placed at the end of the driving end, one end of the driver 8 is fixed on the driver bracket 9 and thus fixed to the base 1, and the other end is fixed or in contact with the driving end.

[0042] Among them, the driver is a linear driver such as a voice coil motor, a piezoelectric ceramic, or a pneumatic driver.

[0043] The rotor and the stator are connected by the flexible hinge. The flexible hinge is divided into eight groups and is centrosymmetric. Each group of hinges is formed by connecting three leaf - spring - type flexible hinges in series, which greatly increases the bearing flexibility, reduces the material stress, and greatly improves the movement stroke of the flexible bearing.

[0044] Among them, the bottom of the carrier 3 protrudes and is connected to the mover without affecting the deformation and movement of the flexible hinge. The optical mirror transferred thereon can also be replaced with an end effector such as a light source or an operating device.

[0045] Among them, the pre-tightening spring is composed of a tension spring 6, a tension spring hook 5, and a tension spring bracket 7. The tension spring hook 5 is connected to the driving end of the flexible hinge bearing through a thread and is further locked and fixed with a nut. The tension spring bracket 7 is fixed to the base with bolts. One end of the tension spring 6 is connected through a screw rod with a through hole at one end. The screw rod can axially move in the through hole of the tension spring bracket and is fixed in position with a nut. Adjusting the front and rear positions of the screw rod can adjust the initial relaxation degree of the tension spring, that is, adjust the initial pre-tightening force on the driver.

[0046] In this embodiment, a semi-circular ball head is provided at the front end of the driver 8, and the semi-circular ball head always maintains point contact with the end of the driving end. The driver is fixed to the base through a driver bracket.

[0047] As Figures 7 - 10 shown, for the case of using a piezoelectric ceramic driver 11 as a linear driver, the piezoelectric ceramic driver 11 is arranged on a piezoelectric ceramic driver bracket 12. Due to the characteristics of high resolution and small output stroke of the piezoelectric ceramic driver 11, a flexible amplification mechanism integrated with the flexible hinge bearing is specially designed to increase the input displacement of the flexible bearing and the output range of the overall platform. The flexible amplification mechanism is a flexible lever type amplification mechanism 10, which can be integrally processed with the flexible hinge bearing by processes such as wire cutting or precision milling to avoid assembly errors. At the same time, the amplification mechanism is still integrated within the base range, with a compact design, high displacement amplification efficiency, and realizing large-stroke and high-precision displacement output.

[0048] A direct-drive large-stroke precision rotation platform proposed by the present invention is composed of a flexible hinge bearing 2, a linear drive device, a spring pre-tightening device, a base 1, etc. The outer ring of the flexible hinge bearing, that is, the stator, is fixed to the base, and the inner ring, that is, the mover, is connected to the outer ring through a group of highly symmetric flexible hinges and extends the driving arm beyond the mover. The linear drive device fixes the linear driver, and the driver directly drives the end of the driving end to drive the stator and the execution components thereon to perform precise rotation under the constraint of the flexible hinge. The spring pre-tightening device plays an output pre-tightening role on the driver to ensure the stable output of the driving displacement and central rotation. In addition, the selection range of the linear driver applicable to the platform is wide, and piezoelectric ceramics, voice coil motors, pneumatic drivers, etc. can be selected. Among them, due to the limited output stroke of piezoelectric ceramics, a specially designed displacement amplification mechanism can be further matched to realize the large-stroke rotation output of the platform. The platform has a large installation area, and the core structure is highly centrally symmetric, which is easy to process and assemble, is beneficial to controlling processing and assembly errors, and obtains the stability of long-term movement.

[0049] The parts not elaborated in the present invention belong to the well-known technologies in the art. The above-described embodiments are only descriptions of the preferred embodiments of the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Without departing from the spirit of the present invention's design, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A direct-drive large-stroke precision rotating platform, characterized in that, The rotating platform comprises: Pedestal; A flexible hinge bearing comprises a flexible hinge, a driving end, a stator and a mover, wherein the stator is fixed on a base, and the driving end is connected to the center of the flexible hinge bearing and extends out of the flexible hinge; A carrier, fixedly connected to the mover, and used to connect the flexible hinge bearing and the end-actuator components; A preload spring, one end of which is fixed to the base and the other end of which is connected to the driving end, for preloading and providing a restoring force; and A driver is disposed at the end of the driving end, one end of the driver is fixed to the driver bracket and then fixed to the base, and the other end is fixed to or in contact with the driving end; The mover and the stator are connected by the flexible hinges, which are divided into eight groups and are centrally symmetrical, and each group of hinges is composed of three leaf spring type flexible hinges connected in series; A semicircular ball head is arranged at the front end of the driver, and the semicircular ball head always keeps point contact with the end of the driving end, and the driver is fixed on the base through a driver bracket.

2. A direct-drive large-stroke precision rotating platform according to claim 1, characterized in that: The end-effector is an optical reflector.

3. A direct-drive large-stroke precision rotating platform according to claim 1, characterized in that: The drive is a linear drive.

4. A direct-drive large-stroke precision rotating platform according to claim 3, characterized in that: The linear drive is a voice coil motor, a piezoelectric ceramic or a pneumatic drive.

5. A direct-drive large-stroke precision rotating platform according to claim 1, characterized in that: The bottom of the carrier protrudes and is connected to the mover, and the end-actuating component connected thereto is an optical reflector, a light source or a manipulator.

6. A direct-drive large-stroke precision rotating platform according to claim 1, characterized in that: The preload spring is composed of a tension spring, a tension spring hook, and a tension spring bracket. The tension spring hook is connected to the driving end of the flexible hinge bearing through a thread and is further locked and fixed with a nut. The tension spring bracket is fixed to the base through a bolt. One end of the tension spring is connected to a screw rod with a through hole at one end. The screw rod can move axially in the through hole of the tension spring bracket and is fixed in position by a nut. The initial tension and relaxation of the tension spring can be adjusted by adjusting the front and rear position of the screw rod, that is, the initial preload force on the driver can be adjusted.

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