CN1669744A - Six-freedom-degree precision positioning workbench - Google Patents

Abstract

A six-degree-of-freedom precision positioning workbench is formed by connecting two platforms, the lower platform having two sets of double parallel plate flexible hinges as guide mechanisms, and using three sets of drive units to achieve translation in two directions and rotation in one direction. The upper platform is partially connected to the motion platform of the lower platform, and three sets of drive units arranged in equilateral triangles and spherical sub-flexible hinges are used to achieve translation in one direction and rotation in two directions. The drive unit uses a piezoelectric ceramic actuator, which makes the displacement output resolution and positioning accuracy high, the frequency response fast, there is no mechanical friction, and the mechanism positioning can achieve compensation. The present invention can achieve nanometer-level positioning accuracy.

Description

Six degrees of freedom precision positioning table

technical field

The invention relates to a workbench, in particular to a precision positioning workbench with six degrees of freedom in space, which can realize nanometer-level positioning accuracy.

Background technique

In the research work of nanotechnology, nanoscale control and positioning are considered to be one of the cores of nanotechnology, which provides a technical basis for the application of nanotechnology in various fields. Nanoscale micropositioning has a wide range of applications in optical engineering, bioengineering, medical engineering, micro-electromechanical systems, ultra-precision machining and measurement. Most of the existing nano-positioning mechanisms in China have one or two degrees of freedom. When multiple degrees of freedom are required, they are realized by combining modules. The structure is relatively large, and there are accumulated errors, so the positioning accuracy is not high. The motion control of the positioning mechanism using the steward structure is very complicated. Some other multi-degree-of-freedom positioning devices use connecting rod transmission, and there is coupling between motions, which also affects positioning accuracy.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a six-degree-of-freedom precision positioning workbench, which should have the characteristics of compact structure, small volume, fast frequency response and compensable positioning error.

Technical solution of the present invention is as follows:

A six-degree-of-freedom precision positioning workbench is characterized in that it consists of an upper platform and a lower platform:

The bottom platform includes a fixed platform, a moving platform, a first parallel-plate flexible hinge, a second parallel-plate flexible hinge, three sets of flexible hinges and connecting bosses, three sets of identical first piezoelectric ceramic actuators and fasteners;

The upper platform is connected with the motion platform of the bottom platform through three sets of identical second piezoelectric ceramic actuators, transmission components, set screws, connecting screws, and locking screws to form a moving whole;

The center line of one group of the three groups of flexible hinges and connecting bosses coincides with the symmetrical center line of the first double-parallel-plate flexible hinge, and the other two groups are symmetrically arranged on both sides of the symmetry axis of the second double-parallel-plate flexible hinge ;Three groups of first piezoelectric ceramic actuators form three groups of driving units in the horizontal plane through their respective fasteners, connecting bosses and flexible hinges;

The three sets of second piezoelectric ceramic actuators driven in the vertical direction are arranged in an equilateral triangle, the lower end of which is embedded in the motion platform of the bottom platform through locking screws, the upper end is connected to the transmission component, and the upper end is connected to the upper layer through set screws and connecting screws. The platform is connected into one; three sets of driving units in the vertical plane are formed by connecting screws, set screws, transmission components, second piezoelectric ceramic actuators and locking screws;

The middle part of the transmission member) is a spherical pair of flexible hinges.

The three sets of flexible hinges are in the form of revolving pair flexible hinges.

The first double-parallel-plate flexible hinge and the eight elastic plates of the second double-parallel-plate flexible hinge on the moving platform have the same size and equal rigidity, forming a double-flexible parallel-guided 4-bar mechanism in two directions.

The advantages of the present invention are: the present invention has small volume, compact structure, and is convenient for processing and assembling. The high-resolution piezoelectric ceramic actuator is used as the driving element, and the flexible hinge is used as the transmission guide unit, so that the resolution of the output displacement is high, the frequency response is fast, the motion transmission is frictionless, and there is no mechanical loss. At the same time, the arrangement of each transmission unit can eliminate the positioning error caused by kinematic coupling, so it can achieve high positioning accuracy.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the present invention

Fig. 2 is a schematic diagram of the underlying platform structure of the present invention

Fig. 3 is a sectional view of the transmission member 5 of the present invention

Detailed ways

First please refer to Fig. 1, Fig. 2 and Fig. 3, as can be seen from the figures, the six-degree-of-freedom precision positioning workbench of the present invention is composed of an upper platform 2 and a bottom platform 1:

The bottom platform 1 includes a fixed platform 1-1, a moving platform 1-2, a first parallel plate flexible hinge 1-3, a second parallel plate flexible hinge 1-4, three groups of flexible hinges 1-5 and connecting Bosses 1-6, three sets of identical first piezoelectric ceramic actuators 8 and fasteners 9;

The upper platform 2 is connected to the motion platform 1-2 of the bottom platform 1 through three sets of the same second piezoelectric ceramic actuator 6, transmission member 5, set screw 4, connecting screw 3, and locking screw 7, form a moving whole;

The center line of one of the three groups of flexible hinges 1-5 and connecting bosses 1-6 coincides with the symmetrical center line of the first double-parallel plate flexible hinge 1-3, and the other two groups are symmetrically arranged on the second double-parallel plate On both sides of the symmetry axis of the flexible hinge 1-4; three groups of first piezoelectric ceramic actuators 8 form three groups of drive units in the horizontal plane through their respective fasteners 9 and connecting bosses 1-6 and flexible hinges 1-5 ;

The three sets of second piezoelectric ceramic actuators 6 driven in the vertical direction are arranged in an equilateral triangle, and their lower ends are embedded in the motion platform 1-2 of the bottom platform 1 through locking screws 7, and the upper ends are connected to the transmission member 5. The set screw 4 and the connecting screw 3 are integrated with the upper platform 2; the connecting screw 3, the set screw 4, the transmission member 5, the second piezoelectric ceramic actuator 6, and the locking screw 7 form three groups in the vertical plane. Drive unit;

The middle part 5-3 of the transmission member 5 is a spherical pair flexible hinge.

The three groups of flexible hinges 1-5 are in the form of rotary pair flexible hinges.

The eight elastic plates of the first double parallel plate flexible hinge 1-3 and the second double parallel plate flexible hinge 1-4 on the motion platform (1-2) have the same size and equal rigidity, forming a double flexible parallel hinge in two directions. Guided 4-bar mechanism.

The bottom platform 1 realizes the translation of the mechanism in the x and y directions and the rotation about the z axis, and the upper platform 2 realizes the rotation about the x and y axes and the translation along the z axis. Four sets of elastic plates 1-4 form a 4-bar mechanism with dual flexible parallel guides in the x direction, which can effectively eliminate the displacement coupling phenomenon in the single parallel guide mechanism. Under the driving force in the x direction and the guidance of the elastic plates 1-4, Realize the displacement in the x direction. Four groups of elastic flat plates 1-3 form a y-direction dual-flexible parallel-guided 4-rod mechanism. When the two groups of first piezoelectric ceramic actuators 8 in the y-direction are elongated at the same time, movement in the y-direction is realized. When the driving forces of the two groups of first piezoelectric ceramic actuators 8 in the y direction are different, the motion platform 1-2 realizes the rotational displacement around the vertical axis z. The function of the flexible hinge 1-5 is to make the rotational movement of the motion platform 1-2 unimpeded. Three groups of flexible hinges 1-5 and one of the connecting bosses 1-6 have their center lines coincide with the symmetrical center lines of the double parallel plate flexible hinges 1-3, and the other two groups are symmetrically arranged on the double parallel plate flexible hinges 1-4 On both sides of the symmetry axis, the positioning error can be effectively corrected and compensated by using this arrangement. The upper platform 2 is connected with the bottom moving platform 1-2 through three sets of the same second piezoelectric ceramic actuator 6, transmission member 5, set screw 4, connecting screw 3, and locking screw 7 to form a moving whole. The horizontal three-dimensional movement of the upper platform 2 is realized through the horizontal three-dimensional movement of the bottom movement platform 1-2. Three sets of second piezoelectric ceramic actuators 6 driven in the vertical direction, the lower end of which is embedded on the bottom motion platform 1-2 through the locking screw 7, the upper end is connected to the transmission member 5, and the set screw 4 and the connecting screw 3 are connected to the The upper platform 2 is connected as a whole. Three groups of drive units in the vertical plane are formed by 3, 4, 5, 6 and 7, and the three groups of drive units are arranged in an equilateral triangle. When the elongation of the three groups of driving units is the same, the translation of the platform 2 along the vertical axis z is realized. When the three sets of drive units are relatively elongated, the platform 2 can realize rotation around the x-axis and y-axis. Transmission member 5 is referring to Fig. 3, and among the figure 5-1 is the connecting screw hole for connecting screw 3, and 5-2 is the connecting screw hole for set screw 4, and 5-4 is the screw hole that is connected for locking screw 7, The middle part 5-3 is a spherical flexible hinge, which has three degrees of freedom, and its function is to make the rotation of the platform 2 unimpeded.

Claims (4)

1, a kind of precision positioning table with six degrees of freedom is characterized in that it is made of upper platform (2) and underlying platform (1):

Comprise fixedly stage body (1-1), motion platform (1-2), the first parallel plate type flexible hinge (1-3), the second parallel plate type flexible hinge (1-4), three groups of flexible hinges (1-5) on the described underlying platform (1) and be connected boss (1-6), three groups of identical first piezoelectric actuators (8) and tightening part (9);

Described upper platform (2) is connected with the motion platform (1-2) of underlying platform (1) by three groups of identical second piezoelectric actuators (6), transmission component (5), holding screw (4), attachment screw (3), lock-screws (7), and it is whole to form a motion;

Three groups of flexible hinges (1-5) overlap other two groups of axis of symmetry both sides that are arranged in second pair of parallel-plate flexible hinge (1-4) symmetrically with one group center line in being connected boss (1-6) with the symmetrical center line of first pair of parallel-plate flexible hinge (1-3); The tightening part (9) of three group of first piezoelectric actuator (8) by separately with is connected the interior driver element of three groups of surface levels of boss (1-6) and flexible hinge (1-5) formation;

Three group of second piezoelectric actuator (6) that vertical direction drives is triangular arranged, its lower end is embedded on the motion platform (1-2) of underlying platform (1) by lock-screw (7), the upper end connects transmission component (5), links into an integrated entity with upper platform (2) by holding screw (4) and attachment screw (3); Form three groups of interior driver elements of vertical plane by attachment screw (3), holding screw (4), transmission component (5), second piezoelectric actuator (6), lock-screw (7).

2, precision positioning table with six degrees of freedom according to claim 1, the center section (5-3) that it is characterized in that described transmission component (5) is the spherical pair flexible hinge.

3, precision positioning table with six degrees of freedom according to claim 1 is characterized in that described three groups of flexible hinges (1-5) form is the revolute pair flexible hinge.

4, according to each described precision positioning table with six degrees of freedom of claim 1 to 3, eight elastic plates measure-alike that it is characterized in that first pair of parallel-plate flexible hinge (1-3) on the motion platform (1-2) and second pair of parallel-plate flexible hinge (1-4), equal stiffness, the double-flexibility parallel conductive of forming both direction is to 4 linkages.

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