CN101862966A - Two-degree-of-freedom parallel decoupling micro-motion platform - Google Patents

Abstract

The invention relates to a two-degree of freedom translation parallel decoupling micromotion platform in the technical field of micro electro mechanical systems. The micromotion platform comprises a piezoelectric ceramic driver, two driving branch chains and corresponding auxiliary branch chains thereof, a working platform and a fixed stand, wherein the two driving branch chains and the corresponding auxiliary branch chains thereof are respectively symmetrically distributed in the X direction and the Y direction of the working platform pairwise. The invention achieves the functions of eliminating coupling and parasitic displacement and realizes the two-dimension movement of the motion platform by the decoupling function and the rigidity characteristic of a compound double-parallel straight panel hinge and the symmetrical characteristic of the whole structure of the platform.

Description

Two-degree-of-freedom parallel decoupling micro-motion platform

technical field

The invention relates to a device in the technical field of micro-electromechanical systems, in particular to a two-degree-of-freedom parallel decoupling micro-motion platform based on a piezoelectric ceramic driver and a flexible hinge.

Background technique

In the fields of micro-electro-mechanical systems, scanning detection microscopes, ultra-precision machining, optical component manufacturing, and biomedical engineering, micro-motion platforms with nanometer precision are the core components. Currently, most employ flexible hinged motion stages with piezoceramic drivers. At present, most of the two-degree-of-freedom micro-motion platforms commonly used in business use two one-dimensional motion platforms vertically superimposed together or nested in a certain direction within another direction platform in a series manner to achieve a two-dimensional sports. However, the two-dimensional micro-motion platform using this connection method will have shortcomings such as cumulative error, parasitic displacement, natural frequency reduction, different dynamic characteristics of the two motion directions, and large volume due to superposition. Therefore, in order to overcome the above shortcomings, the invention of a two-dimensional micro-motion platform with high precision, low inertia, high natural frequency, two-degree-of-freedom structural symmetry, decoupling input and output, and small volume has great significance for practical applications.

After searching the prior art documents, it is found that the Chinese patent application number 200510023219.4, the publication number CN1644329A, and the patent application titled "miniature two-dimensional decoupling workbench" disclose a miniature two-dimensional decoupling workbench. However, in this technology, the configuration is relatively complicated and the processing cost is relatively high. Chinese patent application number 200810636287.2, publication number CN101413902A, a patent application titled "a fully flexible three-translation hybrid micro-motion device for in-situ observation by scanning electron microscope", in which the two-degree-of-freedom part provides a two-degree-of-freedom full Flexible planar parallel mechanism. However, in this technology, if only the driver on a certain degree of freedom is driven, the driver on the other degree of freedom needs to bear a large bending moment and lateral force, which is likely to cause damage to the driver, that is, it cannot be well realized. The input of the electric drive is decoupled. Chinese patent application number 200710114743.1, publication number CN101176995A, a patent application titled "a two-translation micro-motion platform with redundant branch chains", provides a two-translation micro-motion platform with redundant branch chains. However, the single parallel four-bar mechanism used in this technology has coupling displacement when moving, and cannot achieve complete decoupling of two-dimensional motion.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a two-degree-of-freedom translational parallel decoupling micro-motion platform, relying on the decoupling function, stiffness characteristics and symmetry of the overall structure of the platform to eliminate The function of coupling and parasitic displacement realizes the two-dimensional movement of the motion platform.

The present invention is achieved through the following technical solutions. The present invention includes: a piezoelectric ceramic driver, two drive branch chains and their corresponding auxiliary branch chains, a working platform and a fixed frame, wherein: two drive branch chains and their corresponding auxiliary branch chains The auxiliary branch chains are symmetrically distributed in pairs in the X direction and the Y direction of the working platform.

The drive branch chain includes: an input decoupling platform, a drive branch chain intermediate platform, a primary drive hinge intermediate platform, a secondary drive hinge intermediate platform and a flexible hinge, wherein: the input decoupling platform and the drive branch intermediate platform are connected through a flexible The hinges are movably connected, the middle platform of the primary driving hinge is respectively connected with the middle platform of the driving branch chain and the fixed frame through flexible hinges, and the middle platform of the secondary driving hinge is respectively connected with the working platform and the middle platform of the driving branch chain through flexible hinges.

The auxiliary branch chain includes: auxiliary branch chain intermediate platform, first-level auxiliary hinge intermediate platform, second-level auxiliary hinge intermediate platform and flexible hinge, wherein: the first-level auxiliary hinge intermediate platform is connected with the auxiliary branch intermediate platform and the fixed frame respectively The intermediate platform of the secondary auxiliary hinge is respectively connected with the working platform and the intermediate platform of the auxiliary branch chain through flexible hinges.

The head of the piezoelectric ceramic driver is in contact with the input decoupling platform in the drive branch chain and exerts force on the input decoupling platform, and the bottom of the piezoelectric ceramic driver is fixedly connected with the fixed frame.

The drive branch chain and its corresponding auxiliary branch chain, working platform and fixed frame all adopt an integrated structure, that is, it is processed on a piece of metal material board with advanced processing technology, no assembly is required, and the structure is compact. The small size effectively avoids assembly errors and meets the requirements of high precision.

The present invention works in the following way: Taking the movement in the Y direction as an example, the piezoelectric ceramic driver applies force to the input decoupling platform in the drive branch chain in the Y direction to drive the intermediate platform of the branch chain to move in the Y direction, and through the coordination of the flexible hinge deformation, and due to the high axial stiffness of the flexible hinge, the working platform and the auxiliary branch chain in the Y direction are driven to move in the Y direction as a whole. Simultaneously, it also drives the intermediate platform of the secondary drive hinge in the drive branch chain in the X direction and the secondary auxiliary hinge intermediate platform in the auxiliary branch chain to move in the Y direction. Due to the high axial stiffness of the flexible hinge, the displacement of the working platform is basically the same as the output displacement of the piezoelectric ceramic driver, that is, the displacement of the middle platform of the driving branch chain.

Compared with the prior art, the present invention has the following beneficial effects:

(1) Compared with single-parallel and double-parallel hinges, the present invention adopts composite double-parallel straight hinges, which have the advantages of large displacement, low stress concentration and no coupling displacement, and when the driver moves in a certain direction, because the hinge has a larger Axial rigidity, the drive in the other direction bears small bending moments and side loads. Moreover, compared with the right-angle round hinge, the straight hinge used has the advantages of simple structure and shape, convenient processing, and low processing cost.

(2) The present invention adopts a symmetrical constraint structure, thereby effectively eliminating the displacement of the output coupling between the axes, the cumulative error, and the generation of parasitic displacements such as the rotation of the working platform, ensuring the two-degree-of-freedom translation of the motion platform, and also increasing the structure. Stiffness, load carrying capacity and natural frequency.

(3) The parallel mechanism adopted in the present invention has high rigidity, low inertia, high load-carrying capacity, high precision, no cumulative error, the same dynamic characteristics in two directions, symmetrical and compact structure, and small volume compared to the simply superimposed series mechanism Etc.

Description of drawings

Fig. 1 is a system structure block diagram of the present invention.

Figure 2 is a schematic diagram of the deformation principle of the Y-direction mechanism.

Fig. 3 is a diagram showing the relationship between the X-direction displacement of the working platform and the forces applied by the two axes.

Fig. 4 is a diagram showing the relationship between the rotation angle of the working platform and the force applied by the two axes.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

As shown in Figures 1 and 2, this embodiment includes: a piezoelectric ceramic driver 1, two identical driving branch chains 8 and 11 and their corresponding two identical auxiliary branch chains 9 and 10, a working platform 7 and a fixed Frame 2, wherein: the auxiliary branch chains 9, 10 and the drive branch chains 8, 11 are symmetrically distributed in pairs on the X+, X-, Y+, Y- four plane coordinate axis directions of the working platform 7.

The drive branch chain 11 includes: an input decoupling platform 14, a drive branch chain intermediate platform 12, a primary drive hinge intermediate platform 3, a secondary drive hinge intermediate platform 5, and flexible hinges 4, 6 and 13, wherein: the input solution The coupling platform 14 is movably connected with the middle platform 12 of the driving branch chain through the flexible hinge 13, the middle platform 3 of the primary driving hinge is respectively connected with the middle platform 5 of the driving branch chain and the fixed frame 2 through the flexible hinge 4, and the middle platform 12 of the secondary driving hinge The platform is movably connected with the working platform 7 and the intermediate platform 5 of the driving branch chain through the flexible hinge 6 respectively.

Described auxiliary branch chain 9 comprises: auxiliary branch chain intermediate platform 25, primary auxiliary hinge intermediate platform 22, secondary auxiliary hinge intermediate platform 24 and flexible hinges 21 and 23, wherein: primary auxiliary hinge intermediate platform 22 is connected with auxiliary hinge respectively The branch chain intermediate platform 25 is movably connected with the fixed frame 2 through the flexible hinge 21 , and the secondary auxiliary hinge intermediate platform 24 is respectively movably connected with the working platform 7 and the auxiliary branch chain intermediate platform 25 through the flexible hinge 23 .

The working platform 7 is respectively movably connected to the secondary driving hinge intermediate platforms 12 and 16 on the driving branch chains 11 and 8 in the XY directions through the flexible hinges 6, 15, 23 and 30 in the four directions and the corresponding auxiliary On the secondary auxiliary hinge intermediate platforms 24 and 27 on the branch chains 9 and 10.

The fixed frame 2 passes through the flexible hinges 4, 20, 21 and 28 and the primary driving hinge intermediate platforms 3 and 18 on the driving branch chains 11 and 8 in the XY directions and the corresponding auxiliary branch chains 9 and 10. The intermediate platforms 22 and 29 of the primary auxiliary hinge are flexibly connected.

The drive branch chains 8 and 11 and their corresponding auxiliary branch chains 9 and 10, the working platform 7 and the fixed frame 2 all adopt an integrated structure, that is, they are processed on a metal material plate by advanced processing technology , without assembly, compact structure, small size, effectively avoiding the occurrence of assembly errors, and meeting the requirements of high precision.

This example works in the following way: Taking the movement in the Y direction as an example, the piezoelectric ceramic driver 1 applies a force in the Y direction to drive the input decoupling platform 14 in the branch chain 11 to drive the middle platform 5 of the branch chain to move in the Y direction. The coordinated deformation of the hinges 4, 15, 21 and 30, and because the flexible hinges 6 and 23 have relatively high axial rigidity, drive the working platform 7 and the auxiliary branch chain 9 in the Y direction to move in the Y direction as a whole. Simultaneously, it also drives the secondary drive hinge intermediate platform 16 in the drive branch chain 8 in the X direction and the secondary auxiliary hinge intermediate platform 27 in the auxiliary branch chain 10 to move in the Y direction. Since the flexible hinge 6 has relatively high rigidity, the displacement of the working platform 7 is basically the same as the output displacement of the piezoelectric ceramic driver 1 , that is, the displacement of the intermediate platform 5 driven by the branch chain.

Since the flexible hinges 4 and 21 adopt a compound double-parallel structure, the displacement of the intermediate platform 3 of the first-stage driving hinge on the Y-direction drive branch chain 11 is half of that of the middle platform 5 of the drive branch chain in the Y direction, and the displacement of the auxiliary branch chain 9 in the Y direction The displacement of the middle platform 22 of the first-level auxiliary hinge in the Y direction is half of that of the middle platform 25 of the auxiliary branch chain, so the end disturbance of the single straight hinge in the flexible hinges 4 and 21 is Half of the displacement of the platform 25 in the Y direction, and because the flexible hinges 15 and 30 also adopt a composite double parallel structure, the displacement of the secondary drive hinge intermediate platform 16 and the secondary auxiliary hinge intermediate platform 27 is half of the displacement of the working platform 7, so The end disturbance of a single straight hinge in the flexible hinges 15 and 30 is also half of that of the working platform 7, so the composite double parallel structure adopted by the system can better reduce the maximum stress of the flexible hinge.

When only the piezoelectric ceramic driver 1 in the Y direction produces displacement, because the system adopts a composite double parallel four-bar mechanism and the symmetry of the overall structure, the working platform 7 has no output coupling displacement in the X direction, and because the flexible hinges 20 and 28 The axial stiffness is relatively large, so the displacement of the middle platform 19 of the drive branch chain 8 on the drive branch chain 8 in the X direction is very small in the Y direction, and an input decoupling platform 14 is added to the input end of the piezoelectric actuator 1 in the Y direction, Therefore, the bending moment and lateral force borne by the piezoelectric actuator 1 in the Y direction are effectively reduced, and damage to the piezoelectric ceramic actuator 1 is avoided.

As shown in Figure 3, the X-direction displacement of the working platform 7 has a linear relationship with the X-direction input force, and basically has nothing to do with the Y-direction input force, thereby eliminating the coupling in the X direction caused by the change of the input force in the Y direction Displacement, but also eliminates the cumulative error caused by the movement process.

As shown in Figure 4, due to the use of a symmetrical structure and a composite double parallel four-bar mechanism, the rotation angle of the working platform 7 tends to zero during the movement process, which is negligible compared to the displacement in the X and Y directions. Thereby the rotation angle of the working platform 7 is effectively eliminated.

Compared with the existing technology, the device has the following beneficial effects:

(1) This device adopts composite double parallel straight hinges 4, 6, 15, 20, 21, 23, 28, 30, which have the advantages of large displacement, low stress concentration and no coupling displacement compared with single parallel and double parallel hinges, and When the driver moves in one direction, the driver in the other direction bears smaller bending moment and side load because the hinge has a larger axial stiffness. Moreover, compared with the right-angle round hinge, the straight hinge used has the advantages of simple structure and shape, convenient processing, and low processing cost.

(2) The device adopts a symmetrical constraint structure, which effectively eliminates the displacement of the output coupling between the axes, the cumulative error, and the generation of parasitic displacements such as the rotation of the working platform, ensuring the two-degree-of-freedom translation of the motion platform, and also increasing the structure. Stiffness, load carrying capacity and natural frequency.

(3) Compared with the simple stacked series mechanism, the parallel mechanism adopted by this device has high rigidity, low inertia, high load capacity, high precision, no cumulative error, the same dynamic characteristics in two directions, symmetrical and compact structure, and small volume Etc.

Claims (4)

1. two-degree of freedom translation parallel decoupling micromotion platform, piezoelectric ceramic actuator, workbench and fixed frame, it is characterized in that, also comprise: two drive side chain and corresponding auxiliary side chain thereof, and wherein: two driving side chains and corresponding auxiliary side chain thereof are symmetrically distributed in the directions X and the Y direction of workbench respectively in twos.

2. two-degree of freedom translation parallel decoupling micromotion platform according to claim 1, it is characterized in that, described driving side chain comprises: the input decoupling platform, drive the side chain halfpace, one-level drives the hinge halfpace, secondary drive hinge halfpace and flexible hinge, wherein: the input decoupling platform flexibly connects by flexible hinge with driving side chain halfpace, one-level drives the hinge halfpace and flexibly connects by flexible hinge with driving side chain halfpace and fixed frame respectively, and secondary drive hinge halfpace flexibly connects by flexible hinge with workbench and driving side chain halfpace respectively.

3. two-degree of freedom translation parallel decoupling micromotion platform according to claim 1, it is characterized in that, described auxiliary side chain comprises: auxiliary side chain halfpace, one-level secondary hinge halfpace, secondary secondary hinge halfpace and flexible hinge, wherein: one-level secondary hinge halfpace flexibly connects by flexible hinge with auxiliary side chain halfpace and fixed frame respectively, and secondary secondary hinge halfpace flexibly connects by flexible hinge with workbench and auxiliary side chain halfpace respectively.

4. two-degree of freedom translation parallel decoupling micromotion platform according to claim 1, it is characterized in that, the head of described piezoelectric ceramic actuator contact with input decoupling platform in driving side chain and the power that applies in the input decoupling platform, fixedly connected with fixed frame in the bottom of piezoelectric ceramic actuator.

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