阅读说明：本技术 基于柔顺机构的压电超结构模态阻尼增强导向机构及方法 (Piezoelectric superstructure modal damping enhancement guiding mechanism and method based on compliant mechanism ) 是由 陈忠 钟喜能 石俊杰 张宪民 于 2020-11-25 设计创作，主要内容包括：本发明公开了一种基于柔顺机构的压电超结构模态阻尼增强导向机构及方法,包括基座、桥式位移放大机构及导向机构,所述桥式位移放大机构内嵌有压电陶瓷驱动器,导向机构的一端与桥式位移放大机构的输出端连接,桥式位移放大机构的输入端及导向机构的另一端分别与基座连接,所述导向机构包括两根对称设置在桥式位移放大机构输出端两侧的导向梁,导向梁的外表面粘贴有压电超结构。本发明不但能根据导向机构的降价合成模态振型精确地增强导向机构的阻尼,而且所设计的结构简单以及制造成本低廉。(The invention discloses a piezoelectric superstructure modal damping enhancement guide mechanism and method based on a compliant mechanism, and the guide mechanism comprises a base, a bridge type displacement amplification mechanism and a guide mechanism, wherein a piezoelectric ceramic driver is embedded in the bridge type displacement amplification mechanism, one end of the guide mechanism is connected with the output end of the bridge type displacement amplification mechanism, the input end of the bridge type displacement amplification mechanism and the other end of the guide mechanism are respectively connected with the base, the guide mechanism comprises two guide beams symmetrically arranged on two sides of the output end of the bridge type displacement amplification mechanism, and the piezoelectric superstructure is adhered to the outer surface of each guide beam. The invention not only can accurately enhance the damping of the guide mechanism according to the reduced-price synthesis mode shape of the guide mechanism, but also has simple designed structure and low manufacturing cost.)

1. The utility model provides a piezoelectricity superstructure modal damping reinforcing guiding mechanism based on gentle and agreeable mechanism, its characterized in that, including base, bridge type displacement mechanism of amplification and guiding mechanism, bridge type displacement mechanism of amplification is embedded to have the piezoceramics driver, and guiding mechanism's one end is connected with bridge type displacement mechanism of amplification's output, and bridge type displacement mechanism of amplification's input and guiding mechanism's the other end are fixed with the base respectively, guiding mechanism includes the guide beam of two symmetry settings, and two guide beam settings are in bridge type displacement mechanism of amplification output both sides, two surface paste of guide beam have the piezoelectricity superstructure, and two surfaces are the opposite face.

2. The piezoelectric superstructure modal damping enhancement guide mechanism according to claim 1, wherein said piezoelectric superstructure comprises a plurality of piezoelectric shunt units of the same size.

3. The piezoelectric superstructure modal damping enhancement guiding mechanism according to claim 2, wherein the piezoelectric shunt unit comprises a piezoelectric ceramic plate, a lead and energy dissipation electronic components, and upper and lower polar plates of the piezoelectric ceramic plate are respectively externally connected with a shunt circuit to form a loop.

4. The piezoelectric superstructure modal damping enhancement guide mechanism according to claim 3, wherein the piezoceramic sheet is a piezoelectric crystal, a piezoelectric fiber or a piezoelectric polymer.

5. The piezoelectric superstructure modal damping enhancement guide mechanism according to claim 3, wherein said shunt circuitry comprises wires, resistors, synthetic impedances and capacitors.

6. The piezoelectric superstructure modal damping enhancement guide mechanism according to claim 1, wherein the position where the piezoelectric shunt unit is attached and the spacing between adjacent piezoelectric shunt units are determined by the reduced-order composite modal shape and stress magnitude to be controlled.

7. The piezoelectric superstructure modal damping enhancement guide mechanism according to claim 6, wherein in a first-order mode, the larger the stress, the smaller the pitch of the piezoelectric shunt units, and the denser the distribution; when the stress is smaller or zero, the distance between the piezoelectric shunt units is larger or is not attached.

8. The piezoelectric superstructure modal damping enhancement guide mechanism according to claim 6, wherein when any other two or more modal shape damping needs to be controlled, the positions of the piezoelectric shunt units are arranged according to the superposition result of the stress absolute values of the respective modal shapes.

9. A method for enhancing a guide mechanism based on the modal damping of a piezoelectric superstructure of any one of claims 1-8 of the compliant mechanism is characterized in that a piezoelectric ceramic driver generates a small displacement under the action of a control system, the small displacement is amplified by a bridge type displacement amplification mechanism and then output from an output end to drive a guide beam of the guide mechanism to deform, a piezoelectric shunt unit on the guide beam deforms along with the deformation of the guide beam, the piezoelectric shunt unit generates a piezoelectric effect due to the deformation to form a current, and the formed current generates an inverse piezoelectric effect after passing through an external shunt circuit, so that the damping of the flexible guide beam is enhanced to achieve the effect of inhibiting the vibration of the mechanism.

Technical Field

The invention relates to the field of automatic control, in particular to a piezoelectric superstructure modal damping enhancement guide mechanism and method based on a compliant mechanism.

Background

With the rapid development of integrated circuit technology, especially the requirement of 5G chip, the chip manufacturing process is more and more concerned. The photoetching machine is an indispensable key precision device for chip manufacturing process, and the core of the nanometer precision positioning lies in a nanometer precision positioning platform. The compliant mechanism is a core component of the nanometer precision positioning platform, and the dynamic characteristics based on piezoelectric driving can directly limit the motion control bandwidth of the platform. Because it is known from control theory that the maximum control bandwidth of the second order dynamic model is less than twice the product of the natural frequency and the damping ratio, and the maximum bandwidth of the piezoelectric driven compliant mechanism is usually not more than 2% of the first order natural frequency (the damping ratio of the compliant mechanism is generally in the order of 0.01). The end platform of the nanometer precision positioning platform based on the compliant mechanism usually adopts a flexible guide mechanism to ensure the motion positioning precision and the output directivity of the nanometer precision positioning platform. Therefore, the guiding stiffness of the guiding mechanism is usually designed to be large enough and the mass of the guiding mechanism is also designed to be small enough, i.e. the guiding motion control bandwidth of the flexible guiding mechanism is ensured as much as possible with a larger low-order natural frequency. However, the driving capability of the piezoelectric ceramic driver based on the piezoelectric driving compliant mechanism is limited, and the contradiction of the relation between rigidity and output displacement limits the popularization and application of the design idea. Obviously, increasing the damping ratio, i.e. increasing the damping of the flexible guide means, is another better option.

The damping methods studied at present mainly include two types, active damping and passive damping. For active damping, researchers at home and abroad successively put forward active damping control laws of various fixed structures/low orders and complex structures, wherein the fixed structure/low order control laws have poor adaptability to changes of system dynamic characteristics and lose part of piezoelectric driving capability. The control algorithm of the complex structure control law is relatively complex, and the closed-loop control bandwidth of the compliant mechanism can be influenced. For passive damping, common passive damping mainly includes free layer damping, constrained layer damping, piezoelectric shunt damping and the like, wherein the free layer damping and the constrained layer damping can better adapt to the change of the dynamic characteristics of the system, but the broadband characteristics of the free layer damping and the constrained layer damping can cause the energy loss of a non-resonance area of the system, so that the motion agility of the piezoelectric driving compliant mechanism is reduced.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention mainly aims to provide a piezoelectric superstructure modal damping enhancement guide mechanism based on a compliant mechanism.

The invention provides a method for enhancing a guide mechanism by piezoelectric superstructure modal damping based on a compliant mechanism.

The primary purpose of the invention is realized by the following technical scheme:

the utility model provides a piezoelectricity superstructure modal damping reinforcing guiding mechanism based on gentle and agreeable mechanism, includes base, bridge type displacement amplification mechanism and guiding mechanism, bridge type displacement amplification mechanism is embedded to have piezoceramics driver, and guiding mechanism's one end is connected with bridge type displacement amplification mechanism's output, and bridge type displacement amplification mechanism's input and guiding mechanism's the other end are fixed with the base respectively, guiding mechanism includes the guide beam that two symmetries set up, and two guide beam settings are in bridge type displacement amplification mechanism output both sides, and two surface paste of guide beam have piezoelectricity superstructure, and two surfaces are the opposite face.

Further, the piezoelectric superstructure comprises a plurality of piezoelectric shunt units with the same size.

Furthermore, the piezoelectric shunt unit comprises a piezoelectric ceramic piece, a lead and an energy-consuming electronic component, and the upper and lower polar plates of the piezoelectric ceramic piece are respectively externally connected with a shunt circuit to form a loop.

Further, the piezoelectric ceramic piece is a piezoelectric crystal, a piezoelectric fiber or a piezoelectric polymer.

Further, the shunt circuit comprises a lead, a resistor, a synthesized impedance and a capacitor.

Furthermore, the pasting position of the piezoelectric shunt unit and the distance between the adjacent piezoelectric shunt units are determined by the reduced-order synthesis mode shape and the stress magnitude to be controlled.

Further, in a first-order mode, the larger the stress is, the smaller the spacing of the piezoelectric shunt units is, and the denser the distribution is; when the stress is smaller or zero, the distance between the piezoelectric shunt units is larger or is not attached.

Further, when other two or more modal shape damping needs to be controlled, the positions of the piezoelectric shunt units are arranged according to the stress absolute value superposition result of the respective modal shapes.

The secondary purpose of the invention is realized by the following technical scheme:

a piezoelectric ceramic driver generates micro displacement under the action of a control system, the micro displacement is amplified by a bridge type displacement amplification mechanism and then output from an output end to drive a guide beam of the guide mechanism to deform, a piezoelectric shunt unit on the guide beam deforms along with the deformation of the guide beam, the piezoelectric shunt unit generates a piezoelectric effect due to the deformation to form current, and the formed current generates an inverse piezoelectric effect after passing through an external shunt circuit, so that the damping of the flexible guide beam is enhanced to achieve the effect of inhibiting the vibration of the mechanism.

The invention has the beneficial effects that:

(1) the damping enhancement technology used by the invention is passive damping, namely, the mechanism can generate damping without an external power supply and a control system, thereby effectively achieving the aim of enhancing the damping of the mechanism.

(2) The invention reduces the energy loss of the non-resonance area of the system caused by the damping of the free layer or the damping of the constrained layer, thereby ensuring the motion agility of the piezoelectric driving compliant mechanism.

(3) According to the invention, through the corresponding relation between the stress and the piezoelectric shunt unit, the piezoelectric shunt unit can be arranged to accurately control different mode vibration types, and further, the influence caused by the different mode vibration types is accurately controlled in a damping enhancement mode.

(4) The invention has simple manufacturing process and low cost.

Drawings

FIG. 1 is a schematic top view of the overall mechanism of an embodiment of the present invention;

FIG. 2 is a schematic three-dimensional structure of the overall mechanism of an embodiment of the present invention;

FIG. 3(a) is a schematic view of a single guide beam in a first order mode according to an embodiment of the present invention;

FIG. 3(b) is a schematic diagram of a stress state of a single guiding beam in a first-order mode according to an embodiment of the present invention;

fig. 3(c) is a schematic diagram of the position distribution of the piezoelectric shunt unit of a single guide beam in the first-order mode according to the embodiment of the present invention;

FIG. 4(a) is a schematic diagram of a second order mode of a single guide beam according to an embodiment of the present invention;

fig. 4(b) is a schematic diagram of a stress state of a single guide beam in a second-order mode according to an embodiment of the present invention;

fig. 4(c) is a schematic diagram of the position distribution of the piezoelectric shunt unit of a single guide beam in the second-order mode according to the embodiment of the present invention;

fig. 5(a) is a schematic diagram illustrating a superposition result of absolute values of stresses of a first-order mode and a second-order mode of a single guiding beam according to an embodiment of the present invention;

fig. 5(b) is a schematic diagram of the position distribution of the piezoelectric shunt unit when the first-order mode and the second-order mode of the single guide beam are mixed according to the embodiment of the present invention;

fig. 6 is a schematic diagram of a shunt circuit of the piezoelectric shunt unit according to the embodiment of the invention.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited to these examples.

Examples

As shown in fig. 1 and 2, a piezoelectric superstructure modal damping enhancement guide mechanism based on a compliant mechanism is suitable for a compliant mechanism, and mainly comprises a bridge type displacement amplification mechanism 3, a base 1 and a guide mechanism 4.

The specific setting mode is as follows:

the input of bridge type displacement mechanism 3 of amplification is fixed with base 1, bridge type displacement mechanism 3 of amplification is embedded to have piezoceramics driver 2, and guiding mechanism 4 includes the guide beam that two mutual symmetries set up, and the one end setting of two guide beams is in the both sides of bridge type displacement mechanism output of amplification, and its other end is fixed with the base, the surperficial one and two surface of guide beam paste respectively and have piezoelectricity superstructure, and surface one and surface two are the opposite face, and the guide beam is preferred rectangular beam in this embodiment, and its surperficial one and surface two are the upper surface and the lower surface of rectangular beam. The piezoelectric superstructure comprises a plurality of piezoelectric shunt units 5 of the same size.

The specific position where the piezoelectric shunt unit 5 needs to be pasted and the pasting distance d are determined according to the price-reduction synthetic mode shape and the stress magnitude to be controlled. The piezoelectric shunt unit 5 mainly includes a piezoelectric ceramic piece 5x, a wire 501, a resistor Rx, and an inductor Lx. And the upper and lower electrode plates of the piezoelectric ceramic sheet of the piezoelectric shunt unit 5 are respectively externally connected with a shunt circuit to form a loop. The piezoelectric ceramic sheet 5x may be replaced by piezoelectric crystals, piezoelectric fibers, piezoelectric polymers, and the like.

The working process comprises the following steps:

the piezoelectric ceramic driver 2 generates micro displacement under the action of the control system, then the micro displacement is amplified by the bridge type displacement amplification mechanism 3 and then output from the output end to drive the guide beam of the guide mechanism 4 to deform, and then the piezoelectric shunt unit 5 on the guide beam deforms along with the deformation of the guide beam. The piezoelectric shunting unit 5 generates a piezoelectric effect due to deformation to form a current, and the formed current generates an inverse piezoelectric effect after passing through the external shunting circuit, so that the damping of the flexible guide beam is enhanced to achieve the effect of inhibiting the vibration of the mechanism.

The control system used in this embodiment may refer to a system composed of PI controllers or a system composed of IRC controllers, and the like.

The guide mechanism is mainly used for guiding the guide part of the compliant mechanism, and the length of the guide beam is determined according to specific design conditions.

The guide part of the compliant mechanism comprises the guide of a rhombic displacement amplification mechanism, the guide of a bridge type displacement amplification mechanism, the guide of a cylindrical displacement amplification mechanism, the guide of a lever type displacement amplification mechanism and the like.

As shown in fig. 3(a), 3(b) and 3(c), wherein fig. 3(a) is a schematic view of a first-order mode of a single guide beam, fig. 3(b) is a schematic view of a stress state of the single guide beam in the first-order mode, and the positive and negative signs in fig. 3(b) respectively represent tensile stress and compressive stress, that is, the upper surface of the guide beam is in tension and in compression, the transverse stress position thereof corresponds to the actual stress position of the guide beam in the first-order mode one-to-one, and the longitudinal width thereof represents the magnitude of the stress, that is, the wider stress is, and the stress is zero when the width is one point. Fig. 3(c) is a schematic diagram of the position distribution of the piezoelectric shunt units 5 of a single guide beam in a first-order mode, and when the stress is larger, the distance d between the attached piezoelectric shunt units 5 is smaller, that is, the distribution is denser. When the stress is smaller or zero, the pitch d of the attached piezoelectric shunt unit 5 is larger or is not attached. Therefore, on one hand, accurate control can be performed on different mode vibration modes, and on the other hand, the sticking quantity of the piezoelectric shunt units can be reduced.

As shown in fig. 4(a), 4(b) and 4(c), the principle of action is consistent with that shown in fig. 3(a), 3(b) and 3(c), except that fig. 4(a) is a second-order mode diagram of the guide beam, and fig. 3(a) is a first-order mode diagram of the guide beam. Fig. 4(a), 4(b), and 4(c) are used herein to mainly explain that there is a certain difference between the spacing d of the piezoelectric shunt unit 5 and the distribution of the paste positions of the guide beam in different modes, that is, the difference is processed according to the specific mode conditions, so as to achieve the purpose of precise control.

As shown in fig. 5(a) and 5(b), fig. 5(a) is a schematic diagram of a stress absolute value superposition result of a first-order mode and a second-order mode, and fig. 5(b) is a schematic diagram of a position distribution of the piezoelectric shunt unit 5 when the first-order mode and the second-order mode are mixed. When the damping of the guide beam in the first-order mode shape and the second-order mode shape needs to be enhanced simultaneously, the position distribution of the piezoelectric shunt unit can be arranged as shown in fig. 5 (b). Similarly, when any two or more modal shape dampers need to be controlled, the positions of the piezoelectric shunt units 5 can be arranged according to the stress absolute value superposition result of the respective modal shapes.

As shown in fig. 6, the piezoelectric superstructure is composed of a plurality of piezoelectric shunt units 5 with the same size, and the specific positions where the piezoelectric shunt units 5 are attached and the distance d between the piezoelectric shunt units are determined according to the price-reduction composite mode shape and the stress magnitude to be controlled. The piezoelectric shunt unit 5 is composed of an upper and lower electrode plate connecting wire 501 of a piezoelectric ceramic plate 5x, a resistor Rx and an inductor Lx, wherein "x" in symbols "5 x, Rx and Lx" represents the piezoelectric shunt unit corresponding to different positions in different modes. Because the stress distribution at different positions under different modes is different, the required resistance value and inductance value are also different. And because of this, the designed piezoelectric superstructure can achieve the purpose of accurately controlling modal damping. The working principle of the piezoelectric shunt unit 5 is as follows:

when the guide beam on the guide mechanism 4 is deformed by force, the piezoelectric shunt unit 5 adhered on the surface of the guide beam is stretched or compressed. When the piezoelectric shunt unit 5 itself is deformed by an external force, it generates a positive piezoelectric effect. When the upper and lower electrode plates of the piezoelectric ceramic plate 5x are externally connected with a shunt circuit, i.e. connected with the lead 501, the resistor Rx and the inductor Lx shown in fig. 6, charges with opposite polarities on the two electrode plates of the piezoelectric ceramic plate 5x pass through the shunt circuit to generate charge transfer, thereby forming a current. Meanwhile, the voltages on the two polar plates of the piezoelectric ceramic plate 5x can change, and the changed voltages can generate an inverse piezoelectric effect under the action of the load resistor Rx and the inductor Lx and generate a blocking force effect on the guide beam on the guide mechanism 4 in return, so that the vibration of the guide mechanism is limited, the damping of the guide mechanism is increased, and finally the damping of the whole guide mechanism is enhanced.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.