CN112683255A - MEMS fluid gyroscope based on Archimedes spiral microchannel valveless piezoelectric pump - Google Patents
MEMS fluid gyroscope based on Archimedes spiral microchannel valveless piezoelectric pump Download PDFInfo
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Abstract
The invention relates to an MEMS fluid gyroscope based on an Archimedes spiral microchannel valveless piezoelectric pump, which comprises an upper cover, a lower cover and a microcavity, wherein a first piezoelectric vibrator is accommodated in the microcavity, and the MEMS fluid gyroscope also comprises a first plane Archimedes spiral microchannel and a first communicating microchannel which are molded on the upper cover or the lower cover by using an MEMS process, the two ends of the first plane Archimedes spiral micro-channel are respectively connected with a micro-cavity and a fluid inlet, the other end of the fluid inlet is connected with a first micro-channel, the two ends of the first communicating micro-channel are respectively connected with the micro-cavity and a fluid outlet, the other end of the fluid outlet is connected with a second micro-channel, the fluid inlet and the fluid outlet are arranged on the upper cover or the lower cover, the ends, far away from the fluid inlet, of the first micro-flow pipe and the second micro-flow pipe are respectively provided with a piezoelectric unit, and the piezoelectric units are connected with a sensor unit used for measuring the charge variation of the piezoelectric units through leads. The invention has the advantages of simple structure, low cost, small size, wide application range, easy realization and large-scale mass production.
Description
Technical Field
The invention relates to the field of gyroscopes, in particular to an MEMS fluid gyroscope based on an Archimedes spiral microchannel valveless piezoelectric pump.
Background
Gyroscopic technology was originally used for navigation in the sea, but with the development of scientific technology, it has also found widespread use in aviation and aerospace industries. The gyro instrument can be used not only as an indicating instrument, but also as a sensitive element in an automatic control system, namely as a signal sensor. According to the requirement, the gyroscope can provide accurate signals of azimuth, level, position, speed, acceleration and the like, so that a pilot or an automatic navigator is used for controlling navigation bodies such as airplanes, ships or space shuttles to fly according to a certain air route, and in the guidance of the navigation bodies such as missiles, satellite carriers or space detection rockets, the attitude control and the orbit control of the navigation bodies are directly completed by using the signals. Therefore, the application range of the gyroscope instrument is quite wide, and the gyroscope instrument plays an important role in modern national defense construction and national economy construction.
However, the spinning tops on the market at present are expensive, large in size, large in occupied space and mass of carriers, complex in mechanism and not suitable for being applied to some products, and miniaturized and simple liquid spinning tops (such as spinning tops based on multiple piezoelectric pumps) need to be prepared in a fine machining mode, are still large in size and are complex to package. Although MEMS gyroscopes are available on the market, they are basically of solid-state vibration type, and require relatively complicated microelectronic processes such as etching of silicon processes, and their performance depends on the structural design and maturity of the silicon etching technology.
Accordingly, the inventors provide a MEMS fluid gyroscope based on an archimedean spiral microchannel valveless piezoelectric pump.
Disclosure of Invention
(1) Technical problem to be solved
The embodiment of the invention provides an MEMS fluid gyroscope based on an Archimedes spiral microchannel valveless piezoelectric pump, and the MEMS fluid gyroscope is simple in structure, low in cost, small in size and wide in application range by preparing a planar Archimedes spiral microfluidic channel on a pump body of the valveless piezoelectric pump by utilizing an MEMS process and preparing a piezoelectric vibrator by adopting the MEMS process.
(2) Technical scheme
In a first aspect, an embodiment of the present invention provides an MEMS fluid gyroscope based on an archimedean spiral microchannel valveless piezoelectric pump, including an upper cover and a lower cover attached to each other, a microcavity is disposed between the upper cover and the lower cover, a first piezoelectric vibrator is accommodated in the microcavity, a first planar archimedean spiral microchannel formed on the upper cover or the lower cover by an MEMS process is further included, a first communicating microchannel is further disposed on the upper cover or the lower cover, two ends of the first planar archimedean spiral microchannel are respectively connected to the microcavity and a fluid inlet, the other end of the fluid inlet is connected to a first micro-flow tube, two ends of the first communicating microchannel are respectively connected to the microcavity and a fluid outlet, the other end of the fluid outlet is connected to a second micro-flow tube, the fluid inlet and the fluid outlet are both disposed on the upper cover or the lower cover, and piezoelectric units are arranged at the ends, far away from the fluid inlet, of the first micro-flow pipe and the second micro-flow pipe, and are connected with a sensor unit for measuring the charge variation of the piezoelectric units through leads.
Further, the piezoelectric unit comprises a second piezoelectric vibrator or a third piezoelectric vibrator, one end of the first micro-flow tube, which is far away from the fluid inlet, is connected with the second piezoelectric vibrator, one end of the second micro-flow tube, which is far away from the fluid outlet, is connected with the third piezoelectric vibrator, the sensor unit comprises a first sensor or a second sensor, and the second piezoelectric vibrator is connected with the first sensor through the lead; and the third piezoelectric vibrator is connected with the second sensor through the lead.
Further, the piezoelectric unit further comprises a piezoelectric vibrator fixing member for fixing the second piezoelectric vibrator or the third piezoelectric vibrator on the first micro-flow tube or the second micro-flow tube.
Furthermore, a second communication micro-channel is arranged between the first plane Archimedes spiral micro-channel and the micro-cavity, and two ends of the second communication micro-channel are respectively communicated with the first plane Archimedes spiral micro-channel and the micro-cavity.
Further, a second planar archimedean spiral microchannel formed on the upper cover or the lower cover by an MEMS process is disposed on the upper cover or the lower cover, and two ends of the second planar archimedean spiral microchannel are respectively communicated with the first communication microchannel and the fluid outlet.
Further, the first planar archimedean spiral microchannel is an archimedean spiral microchannel centered on the fluid inlet and starting from the fluid inlet and arranged in a counterclockwise direction, the second planar archimedean spiral microchannel is an archimedean spiral microchannel centered on the fluid outlet and starting from the fluid outlet and arranged in a clockwise direction, the first planar archimedean spiral microchannel and the second planar archimedean spiral microchannel are symmetrically arranged on the upper cover or the lower cover, and the fluid inlet and the fluid outlet are symmetrically arranged on both sides of a center line of the microcavity.
Furthermore, the upper cover or the lower cover is integrally formed by pouring PDMS material, the first plane Archimedes spiral micro-channel is formed by pouring the PDMS material on a male die with the same shape as the first plane Archimedes spiral micro-channel and curing, and the male die is patterned by SU-8 photoresist.
Furthermore, a first groove is formed in the lower cover, a second groove is formed in the upper cover, the first groove and the second groove are in sealing fit to form the micro-cavity, the first piezoelectric vibrator is contained in the second groove, and the second groove is arranged in a step shape.
Further, the micro-cavity is formed on the lower cover through an MEMS process, and the cross section of the micro-cavity is circular.
Furthermore, the first piezoelectric vibrator, the second piezoelectric vibrator and the third piezoelectric vibrator have the same structure, the first piezoelectric vibrator comprises a substrate and a conducting layer formed on the substrate in a sputtering mode, the conducting layer comprises a metal layer and a piezoelectric functional material layer, the piezoelectric functional material layer is embedded into the substrate, the metal layer is located above the piezoelectric functional material layer, the substrate is made of silicon materials, and the piezoelectric functional material layer is made of inorganic piezoelectric materials.
(3) Advantageous effects
In conclusion, the planar Archimedes spiral microfluidic channel is prepared on the pump body of the valveless piezoelectric pump by using the MEMS technology (micro-nano processing technology), and the piezoelectric vibrator is prepared by using the MEMS technology, so that the MEMS fluid gyroscope has the advantages of simple structure, low cost, small size, wide application range and easy realization and large-scale mass production. The device has good sensitivity to the safety of rotation, and can be widely applied to the rollover posture control of the vehicle; the pump has the advantages of being easy to miniaturize, low in energy consumption, fast in response and free of electromagnetic interference.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic view of the structure of a valveless piezoelectric pump of the present invention.
Fig. 2 is a schematic view of the structure of the lower cover of the present invention.
Fig. 3 is a schematic view of the structure of the upper cover of the present invention.
Fig. 4 is a cross-sectional view of the upper cover of the present invention.
Fig. 5 is another schematic view of the valveless piezoelectric pump of the present invention.
Fig. 6 is a schematic structural view of the piezoelectric unit of the present invention.
Fig. 7 is a schematic view of the structure of the piezoelectric vibrator of the present invention.
Fig. 8 is another structural schematic diagram of the lower cover of the present invention.
In the figure:
1-a first microchannel; 2-a second microchannel; 3-covering the cover; 4-a first piezoelectric vibrator; 5-lower cover; 6-first alignment mark; 7-a second alignment mark; 8-a first planar archimedean spiral microchannel; 9-a fluid inlet; 10-a second communicating microchannel; 11-a microcavity; 12-a first communicating microchannel; 13-a fluid outlet; 15-a first mounting hole; 16-a third mounting hole; 17-a second mounting hole; 18-a piezoelectric element; 19-a wire; 20-a first sensor; 21-valveless piezoelectric pump; 22-a piezoelectric vibrator mount; 23-a second piezoelectric vibrator; 24-a third piezoelectric vibrator; 25-a third alignment mark; 26-a second sensor; 27-a fourth alignment mark; 28-a second planar archimedean spiral microchannel; 41-a substrate; 42-a conductive layer; 111-a first recess; 112-second groove.
Detailed Description
The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the invention and are not intended to limit the scope of the invention, i.e., the invention is not limited to the embodiments described, but covers any modifications, alterations, and improvements in the parts, components, and connections without departing from the spirit of the invention.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
Fig. 1 is a schematic structural diagram of a MEMS fluid gyroscope of an archimedean spiral microchannel valveless piezoelectric pump according to an embodiment of the present invention, as shown in fig. 1, fig. 2 and fig. 5, the MEMS fluid gyroscope includes an upper cover 3 and a lower cover 5 attached to each other, a microcavity 11 is disposed between the upper cover 3 and the lower cover 5, a first piezoelectric vibrator 4 is accommodated in the microcavity 11, a first planar archimedean spiral microchannel 8 formed on the upper cover 3 or the lower cover 5 by using a MEMS process is further included, a first communicating microchannel 12 is further disposed on the upper cover 3 or the lower cover 5, two ends of the first planar archimedean spiral microchannel 8 are respectively connected to an 11 and a fluid inlet 9, the other end of the fluid inlet 9 is connected to a first micro-fluidic tube 1, two ends of the first communicating microchannel 12 are respectively connected to the microcavity 11 and a fluid outlet 13, the other end of the fluid outlet 13 is connected to a second micro-fluidic tube 2, the fluid inlet 9 and the fluid outlet 13 are both arranged on the upper cover 3 or the lower cover 5, the upper cover 3 or the lower cover 5 is both provided with a first mounting hole 15 and a second mounting hole 17 for mounting the first micro-flow tube 1 and the second micro-flow tube 2, one ends of the first micro-flow tube 1 and the second micro-flow tube 2 far away from the fluid inlet 9 are both provided with a piezoelectric unit 18, the piezoelectric unit 18 is connected with a sensor unit for measuring the charge variation of the piezoelectric unit 18 through a lead 19, specifically, the sensor unit can also conduct the charge variation signal, and the MEMS process comprises patterning a male die (not shown in the figure) of a first plane Archimedes spiral micro-channel by using SU-8 photo-etching negative glue; then pouring PDMS (polydimethylsiloxane) on the male die, and stripping the male die after curing to obtain the first plane Archimedes spiral micro-channel 8 made of PDMS. In this embodiment, the lower cover 5 is a rectangular plate made of a PDMS material, the upper cover 3 is a rectangular plate made of a PDMS material or a rectangular aluminum plate made of an aluminum alloy material, the first planar archimedean spiral microchannel 8 is first processed into a mold, i.e., a punch of the first planar archimedean spiral microchannel 8 on the lower cover 5, by an MEMS process, and then the PDMS material is poured on the punch to integrally form the lower cover 5 having the first planar archimedean spiral microchannel 8, and the first communication microchannel 12 is correspondingly disposed on the lower cover 5, it should be noted that the first planar archimedean spiral microchannel 8 can also be disposed on the upper cover 3, so that the upper cover 3 can only be made of a PDMS material, and the lower cover 5 can be made of a rectangular plate made of a PDMS material or an aluminum alloy material. In order to improve the efficiency of packaging the upper cover 3 and the lower cover 5, the first alignment mark 6 and the second alignment mark 7 are respectively arranged on the lower cover 5, the third alignment mark 25 and the fourth alignment mark 27 are arranged on the upper cover 3, and before packaging, the first alignment mark 6 and the fourth alignment mark 27 and the second alignment mark 7 and the third alignment mark 25 are respectively aligned, so that the upper cover 3 and the lower cover 5 are ensured to be aligned and attached, and the packaging quality and speed are improved.
According to the invention, the MEMS process (micro-nano processing technology) is utilized to prepare the planar Archimedes spiral microfluidic channel on the pump body of the valveless piezoelectric pump and the MEMS process is adopted to prepare the piezoelectric vibrator, so that the MEMS fluid gyroscope has the advantages of simple structure, low cost, small size, wide application range and easiness in realization and large-scale mass production.
As a preferred embodiment, as shown in fig. 1, 5 and 6, the piezoelectric unit 18 includes a second piezoelectric vibrator 23 or a third piezoelectric vibrator 24, the end of the first microchannel 1 away from the fluid inlet 9 is connected to the second piezoelectric vibrator 23, the end of the second microchannel 2 away from the fluid outlet 13 is connected to the third piezoelectric vibrator 24, the sensor unit includes a first sensor 20 or a second sensor 26, and the second piezoelectric vibrator 23 is connected to the first sensor 20 through a lead 19; the third piezoelectric vibrator 24 is connected to the second sensor 26 via a wire 19. The first sensor and the second sensor can be used for measuring the charge variation of the second piezoelectric vibrator and the third piezoelectric vibrator respectively, and the charge variation and the conversion of the impact pressure are analyzed, so that the output pressure of the valveless piezoelectric pump is calculated.
As another preferred embodiment, as shown in fig. 6, the piezoelectric unit 18 further includes a piezoelectric vibrator fixing member 22 for fixing the second piezoelectric vibrator 23 or the third piezoelectric vibrator 24 on the first microchannel 1 or the second microchannel 2. The piezoelectric array fixing member 22 is integrally formed with the second piezoelectric vibrator 23 or the third piezoelectric vibrator 24, and is connected to the first micro flow tube or the second micro flow tube through the piezoelectric vibrator fixing member, so that the second piezoelectric vibrator or the third piezoelectric vibrator is connected to the corresponding first micro flow tube or the second micro flow tube, respectively.
As other alternative embodiments.
Preferably, as shown in fig. 1 and fig. 2, a second communication microchannel 10 is provided between the first planar archimedean spiral microchannel 8 and the microcavity 11, and both ends of the second communication microchannel 10 are respectively communicated with the first planar archimedean spiral microchannel 8 and the microcavity 11.
Preferably, in the present invention, based on that one planar archimedean spiral microchannel is adopted in the archimedean spiral microchannel valveless piezoelectric pump to achieve unidirectional flow of fluid in the pump body, or two planar archimedean spiral microchannels are adopted to achieve bidirectional flow, as shown in fig. 8, a second planar archimedean spiral microchannel 28 is formed on the upper cover 3 or the lower cover 5 by an MEMS process, both ends of the second planar archimedean spiral microchannel 28 are respectively communicated with the first communication microchannel 12 and the fluid outlet 13, the first planar archimedean spiral microchannel 8 is an archimedean spiral microchannel with the fluid inlet 9 as a center and the starting point being in a counterclockwise direction, the second planar archimedean spiral microchannel 28 is an archimedean spiral microchannel with the fluid outlet 13 as a center and the starting point being in a clockwise direction, and the first planar archimedean spiral microchannel 8 and the second planar archimedean spiral microchannel 28 are symmetrically arranged The fluid inlet 9 and the fluid outlet 13 are arranged symmetrically on both sides of the center line of the microcavity 11 as on the upper cover 3 or the lower cover 5. It should be noted here that, both the first planar archimedean spiral microchannel 8 and the second planar archimedean spiral microchannel 28 are prepared by the MEMS process, and compared with a planar archimedean spiral microchannel, only another male mold (not shown in the drawings) for patterning the first planar archimedean spiral microchannel and the second planar archimedean spiral microchannel 28 by using the SU-8 photoresist is needed, and then the PDMS material is integrally cast for integrally molding the lower cover 5 having the first planar archimedean spiral microchannel 8 and the second planar archimedean spiral microchannel 28. It should be noted that the first planar archimedean spiral microchannel 8 and the second planar archimedean spiral microchannel 28 can be formed on the cover 3 by the same forming process.
Preferably, as shown in fig. 1, 2 and 4, the lower cover 5 is provided with a first groove 111, the upper cover 3 is provided with a second groove 112, the upper cover 3 is provided with a third mounting hole 16, the second groove 112 is provided in the third mounting hole 16, when packaging is performed, a cover plate is additionally provided to seal the third mounting hole, the first groove 111 and the second groove 112 are in sealing fit to form the microcavity 11, the first piezoelectric vibrator 4 is accommodated in the second groove 112, and the second groove 112 is designed to be stepped in order to achieve the best effect when the first piezoelectric vibrator is operated and consider the arrangement and processing of other structures on the pump body of the valveless piezoelectric pump 21. The microcavity 11 can be disposed on the lower cover 5 and has an opening facing the upper cover 3, or disposed on the upper cover 3 and has an opening facing the lower cover 5, the microcavity 11 is formed on the lower cover 5 by an MEMS process, and the cross section of the microcavity 11 is circular and is adapted to the shape of the first piezoelectric vibrator 4.
Preferably, the first piezoelectric vibrator 4, the second piezoelectric vibrator 23 and the third piezoelectric vibrator 24 have the same structure, and a specific structure of one of the piezoelectric vibrators is described below, as shown in fig. 7, the first piezoelectric vibrator 4 includes a substrate 41 and a conductive layer 42 formed on the substrate 41 by a sputtering process, the conductive layer 42 includes a metal layer and a piezoelectric functional material layer, the piezoelectric functional material layer is embedded into the substrate 41 and is integrally embedded with the substrate 41, the metal layer is located above the piezoelectric functional material layer, the substrate 41 is made of a silicon material, the piezoelectric functional material layer is made of an inorganic piezoelectric material, the metal layer is a gold layer, the piezoelectric functional material layer is made of an inorganic piezoelectric material, and the inorganic piezoelectric material may be one or more selected from piezoelectric ceramics, quartz (quartz crystal), lithium gallate, lithium germanate, titanium germanate, and lithium niobate of iron transistor, preferably, the piezoelectric functional material layer is a piezoelectric ceramic sheet.
The sensor (20,26) of the invention can measure the charge variation of the piezoelectric vibrator (23,24) and analyze the charge variation and the conversion of the impact pressure according to the analysis device. The principle of the piezoelectric vibrator is that the piezoelectric vibrator utilizes the positive piezoelectric effect to realize the electromechanical conversion, namely when the piezoelectric material is subjected to mechanical stress, electric polarization is generated, so that electric charges are generated, and the generated electric charges are in direct proportion to the mechanical stress. The magnitude of the applied force can be obtained by measuring and analyzing the generated electric signal by using a signal analysis device. When the pressure on the piezoelectric vibrator is different, the generated charges of the piezoelectric vibrator are different, and after the charge signals are amplified by the charge amplifier and converted into electric signals, the electric signals are transmitted to a computer through an analog-to-digital converter to be analyzed and calculated, and test results are given. In the present invention, the output pressure of the pump is measured using a piezoelectric vibrator force sensor.
When the novel MEMS liquid gyroscope based on the Archimedes spiral microchannel valveless piezoelectric pump works, alternating voltage is applied to the piezoelectric vibrator firstly, and the piezoelectric vibrator generates axial vibration under the inverse piezoelectric effect to cause the change of the volume of a microcavity; a cycle of a piezoelectric pump can be generally divided into two phases: a suction stroke stage of the pump is that the pump reaches a top dead center (the maximum displacement of the piezoelectric vibrator far away from the balance position outside the microcavity) from a bottom dead center (the maximum displacement of the piezoelectric vibrator far away from the balance position in the microcavity) through the balance position; reaching bottom dead center from top dead center through the equilibrium position is the scheduling stage for the pump. When the piezoelectric vibrator moves from a bottom dead center to a top dead center, namely the volume of the micro-cavity is converted from minimum to maximum, fluid on one side directly enters the micro-cavity from the first communicating micro-channel, and fluid on the other side enters the micro-cavity through the first spiral micro-channel or enters the micro-cavity through the second communicating micro-channel; when the piezoelectric vibrator moves from the top dead center to the bottom dead center, namely the volume of the micro-cavity is converted from the maximum to the minimum, the fluid is discharged from the micro-cavity outwards through the communicating micro-channels at the two sides, and the flowing direction of the fluid in the spiral micro-channel is the direction in which the curvature of the spiral micro-channel is gradually increased. Because of the different changes of the curvature, the curvature is gradually increased and is influenced by the earth Coriolis force and the spin Coriolis force, the resistance of the fluid is gradually increased, the curvature is gradually reduced and is influenced by the opposite action of the earth Coriolis force and the spin Coriolis force, the resistance is gradually reduced, so that the resistance of the fluid flowing in the reciprocating direction through the spiral microchannel is different, the flow of the fluid flowing into the microcavity from the spiral microchannel on one side is different from the flow of the fluid flowing out from the microcavity to the other side, a net flow flows flowing to the outlet microchannel from the inlet microchannel in the whole period, and when the piezoelectric vibrator continuously vibrates, the fluid macroscopically flows in a single direction to realize the function of the pump.
When the whole gyro structure is installed on the bearing platform, if the bearing platform is influenced by the rotating angular speed, such as the bearing platform is installed on a carrier, when the carrier turns and rotates, the whole rotation can influence the performance of the Archimedes spiral microchannel valveless piezoelectric pump in the gyro structure.
The component of the angular velocity of the earth's rotation in the Z axis is
The angular velocity of the fluid flowing along the Archimedes spiral micro-fluidic tube is omega2When the platform is disturbed by the outside, the component of the generated angular velocity on the Z axis is omegaz(ii) a The output pressure P of the pump is
ω2、ωzDetermined, therefore, can be expressed as
If the platform is not subjected to external disturbance omegazThe output performance of the pump is controlled by
And ω2When the voltage and the frequency input to the piezoelectric vibrator are determined to be constant, the performance of the pump is determined to be constant, the impact of the liquid in the inlet and outlet microflow pipes on the piezoelectric vibrator is also approximately constant, the reading of the sensor is basically constant after reaction, and the reading of the sensor at the outlet minus the reading of the sensor at the inlet is assumed to be delta x0I.e. the output pressure of the pump is P0There is a correspondence between them. If the platform is disturbed by external disturbance omegazWhen interfering with each other, ωzNot equal to 0, provided with
At the moment, the fluid flow in the Archimedes spiral groove is strengthened or weakened, the influence on the performance of the pump is shown on the reading of a sensor connected with a micro-flow pipe at an inlet and an outlet, and if the reading at the outlet side of the sensor is x1The index on the inlet side is x2Then set Δ x1＝x1-x2，ΔP＝P-P0＝Δx0-Δx1Δ P may be a positive value, or may be a negative value and zero. There is a correspondence between Δ P (or P) and ω, i.e. for each value of Δ P (or P), there is one ω corresponding toAnd Δ P and Δ x have a correspondence relationship. That is to say, the sensor measures the impact delta x of the liquid in the spiral micro-flow pipe valveless piezoelectric pump on the piezoelectric vibrator, and the component omega of the angle generated when the platform is disturbed on the Z axis can be obtainedz. Therefore, the rotation attitude can be obtained according to the relation between the pressure difference and the rotation of the pump, and the action of the gyroscope is achieved.
To further illustrate the technical effects of the present invention, the following description is made in conjunction with the working principle of the present invention, as shown in fig. 1 to 8, the working process of the spinning top of this embodiment is as follows: alternating voltage is applied to the first piezoelectric vibrator 4, the first piezoelectric vibrator 4 generates axial vibration on two sides of a balance position under the inverse piezoelectric effect, and the axial vibration displacement causes the volume change of the microcavity. One working cycle of the valveless piezoelectric pump 21 is divided into two phases: a suction stroke stage of the valveless piezoelectric pump 21 from a bottom dead center (the maximum displacement of the first piezoelectric vibrator 4 which is far from the equilibrium position downwards) to a top dead center (the maximum displacement of the first piezoelectric vibrator 4 which is far from the equilibrium position upwards) through the equilibrium position; reaching bottom dead center from top dead center through the equilibrium position is the scheduling stage for the valveless piezoelectric pump 21. When the valveless piezoelectric pump 21 is in a suction range, the volume of the microcavity 11 is increased, the pressure is decreased, the fluid in the first communicating microchannel 12 and the second communicating microchannel 10 flows into the microcavity 11 under the action of negative pressure, when the fluid flowing in from the fluid inlet 9 passes through the first archimedean spiral channel 8, namely the groove, due to the influence of the earth coriolis force and the spin coriolis force, the change direction of the spiral curvature of the first archimedean spiral microchannel 8 is gradually decreased, and the obstruction to the flow of the fluid is small in relation to the process of the gradually increasing spiral curvature, so that the flow rate entering the microcavity 11 is relatively large, when the valveless piezoelectric pump 21 enters the schedule, the volume of the microcavity 11 is decreased, and the fluid in the microcavity 11 flows out to the first communicating microchannel 12 and the second communicating microchannel 10 on both sides under the pressure, when the fluid flowing from the microcavity 11 to the first planar archimedean spiral microchannel 8 passes through the spiral microchannel, because the opposite effect of the earth Coriolis force and the spin Coriolis force is applied to the process that the curvature of the spiral line is gradually increased, the curvature of the opposite spiral line is gradually reduced, at the moment, the degree of the first Archimedes spiral channel 8 hindering the fluid is large, the flow rate flowing out from the microcavity 11 to the first Archimedes spiral channel 8 is relatively small, a flow difference is generated in the reciprocating process, the suction distance of the microcavity 11 is basically equal to the scheduled volume change, the flow rate flowing out from the microcavity 11 to the first communicating micro channel 12 is larger than the flow rate flowing in from the second communicating micro channel 10 to the microcavity 11, a net flow rate with unidirectional motion is generated in the whole period, and when the first piezoelectric vibrator 4 continuously vibrates, the fluid shows unidirectional flow on the macro scale, so that the function of the valveless piezoelectric pump 21 is formed. When the input condition is fixed for the first piezoelectric vibrator 4, the liquid level of the fluid in the first micro-flow pipe 1 is fixed, the impact action on the first piezoelectric vibrator 4 is approximately the same, the value reflected in the first sensor 20 (charge sensor) is a constant value with a small change amplitude, if the bearing platform is influenced by the rotation angular velocity, the whole rotation can influence the performance of the valveless piezoelectric pump 21 of the Archimedes spiral micro-channel in the gyroscope structure, if the reinforcing action is generated in the clockwise flow direction of the fluid to weaken the anticlockwise flow, the output performance of the pump can be improved, so that the liquid level in the second micro-flow pipe 2 rises, the liquid level can also improve the impact on the third piezoelectric vibrator 24 installed in the second micro-flow pipe 2, and if the reinforcing action is generated in the anticlockwise flow direction of the fluid to weaken the clockwise flow, the output performance of the valveless piezoelectric pump 21 is reduced, so that the liquid level at the outlet is lowered, the impact of the liquid level on the third piezoelectric vibrator 24 installed therein is weakened, the rotational angular velocity acts on the fluid flow direction in general, the output performance of the valveless piezoelectric pump 21 is affected, the liquid level in the first micro-fluid pipe 1 and the second micro-fluid pipe 2 is changed, the impact of the liquid level on the second piezoelectric vibrator 23 and the second piezoelectric vibrator 24 installed therein is also changed, the value is measured according to the charge change of the first sensor 20 and the second sensor 26 on the corresponding second piezoelectric vibrator 23 and the third piezoelectric vibrator 24 due to the piezoelectric effect, the pressure difference change of the valveless piezoelectric pump 21 can be obtained according to the data measured at the two sides, and the rotational attitude can be obtained according to the relationship between the pressure difference and the rotation of the valveless piezoelectric pump 21 measured at the initial test, thereby achieving the function of a gyroscope.
The main structure of another embodiment is substantially the same as that of the previous embodiment, except that in another embodiment, two first planar archimedean spiral microchannels 8 and two second planar archimedean spiral microchannels 28 are arranged in the valveless piezoelectric pump 21 portion, which are symmetrical about the center line of the circular microcavity 11, the first planar archimedean spiral microchannels 8 are arranged in a counterclockwise direction with the fluid inlet 9 as the center and the starting point, and the second planar archimedean spiral microchannels 28 are arranged in a clockwise direction with the fluid outlet 13 as the center and the starting point. When the gyroscope of this embodiment is in operation, the metal layer and the piezoelectric functional material layer of the piezoelectric vibrator are used as two electrodes, and when an alternating current is applied to the first piezoelectric vibrator 4, the piezoelectric functional material layer will generate a stretching deformation along the radial direction thereof, because the substrate 41 made of silicon material and the piezoelectric functional material layer are integrated and their radial stretching is different, when the piezoelectric functional material layer generates a stretching deformation along the radial direction, the substrate 41 will also generate a stretching deformation, and the stretching direction is opposite to that of the piezoelectric functional material layer, the first piezoelectric vibrator 4 will inevitably generate a reciprocating deformation vibration along the axial direction (the normal direction of the piezoelectric functional material), and the first piezoelectric vibrator 4 is used as a power source of the valveless piezoelectric pump 21, and vibrates along with the axial reciprocating deformation of the first piezoelectric vibrator 4, thereby causing a periodic change in the volume of the microcavity 11. Because the motion of the fluid is influenced by the earth rotation, and the fluid can generate Coriolis force when moving along the planar Archimedes spiral microchannel, so as to generate different effects on the fluid rotating along the anticlockwise direction and the clockwise direction, the resistance of the fluid flowing into the fluid inlet and the fluid flowing out of the fluid outlet is different, and the volume of the fluid flowing into or out is inversely proportional to the flow resistance of the micro-channel, when the volume of the micro-cavity 11 is increased, the fluid flows into the micro-cavity 11 from the first planar Archimedes spiral microchannel 8 and the second planar Archimedes spiral microchannel 28, at this time, the valveless piezoelectric pump 21 is in the suction stroke stage, but the volumes of the fluid flowing into the micro-cavity 11 from the first micro-channel 1 and the second micro-channel 2 are different; when the volume of the microcavity 11 is reduced, the fluid flows out of the microcavity 11 from the first planar archimedean spiral microchannel 8 and the second planar archimedean spiral microchannel 28, and at this time, the valveless piezoelectric pump 21 is in a discharge stage, but the volumes of the fluid flowing out of the microcavity 11 from the first micro-fluidic tube 1 and the second micro-fluidic tube 2 are different; analyzing how much the volume of fluid flows in and out from the two microchannels when the valveless piezoelectric pump 21 is in the intake and exhaust phases can be summarized as: when the valveless piezoelectric pump 21 is in the suction stage and the volume of the inflow fluid is large, the volume of the outflow fluid is small when the valveless piezoelectric pump 21 is in the discharge stage; when the valveless piezoelectric pump 21 is in the suction phase, the volume of the inflow fluid is small, and when the valveless piezoelectric pump 21 is in the discharge phase, the volume of the outflow fluid is large; macroscopically, the valveless piezoelectric pump 21 always enables fluid to flow in from one micro-fluidic tube and flow out from the other micro-fluidic tube, so that unidirectional fluid flow is realized, and the function of the pump is realized. When the input condition is fixed for the first piezoelectric vibrator 4, the fluid level height in the first micro-flow tube 1 and the second micro-flow tube 2 will be fixed, the impact action on the first piezoelectric vibrator 4 is approximately the same, the value reflected in the first charge sensor 20 and the second charge sensor 26 is a constant value with a smaller change amplitude, if the bearing platform is affected by the rotation angular velocity, the whole rotation will affect the performance of the archimedean spiral micro-channel valveless piezoelectric pump 21 in the gyroscope structure, if the fluid clockwise flow direction generates the strengthening action and generates the weakening action on the counterclockwise flow, the output performance of the pump will be improved, so that the liquid level in the second micro-flow tube 2 will be raised, the liquid level will also raise the impact on the third piezoelectric vibrator installed in the second micro-flow tube, if the fluid clockwise flow direction generates the strengthening action and generates the weakening action on the counterclockwise flow, the output performance of the pump is reduced, the liquid level of the liquid at the outlet is lowered, the impact of the liquid level on the piezoelectric vibrators installed in the liquid level is weakened, the rotation angular velocity acts on the flow direction of the fluid on the whole, the output performance of the pump is affected, the liquid level in the first micro-flow pipe 1 and the liquid level in the second micro-flow pipe 2 are changed, the impact of the liquid level on the piezoelectric vibrators installed in the liquid level can be changed, the value is measured according to the charge change of the charge sensor on the second piezoelectric vibrator third piezoelectric vibrator 24 due to the piezoelectric effect, the pressure difference change of the pump can be obtained according to the data measured at the two sides, the rotation posture can be obtained according to the relation between the pressure difference and the rotation of the pump measured in an initial test, and the action of the gyroscope is achieved.
It should be clear that the embodiments in this specification are described in a progressive manner, and the same or similar parts in the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the drawings. Also, a detailed description of known process techniques is omitted herein for the sake of brevity.
The above description is only an example of the present application and is not limited to the present application. Various modifications and alterations to this application will become apparent to those skilled in the art without departing from the scope of this invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims (10)
1. An MEMS fluid gyroscope based on an Archimedes spiral microchannel valveless piezoelectric pump comprises an upper cover (3) and a lower cover (5) which are attached to each other, a microcavity (11) is arranged between the upper cover (3) and the lower cover (5), a first piezoelectric vibrator (4) is accommodated in the microcavity (11), the MEMS fluid gyroscope is characterized by further comprising a first plane Archimedes spiral microchannel (8) formed on the upper cover (3) or the lower cover (5) by adopting an MEMS process, a first communication microchannel (12) is further arranged on the upper cover (3) or the lower cover (5), two ends of the first plane Archimedes spiral microchannel (8) are respectively connected with the microcavity (11) and a fluid inlet (9), the other end of the fluid inlet (9) is connected with a first micro-flow pipe (1), two ends of the first communication microchannel (12) are respectively connected with the microcavity (11) and the fluid outlet (13), the other end of fluid outlet (13) is connected with second miniflow pipe (2), fluid inlet (9) with fluid outlet (13) are all located upper cover (3) or on lower cover (5), first miniflow pipe (1) with second miniflow pipe (2) are kept away from the one end of fluid inlet (9) all is provided with piezoelectric unit (18), piezoelectric unit (18) pass through wire (19) and are used for measuring the sensor unit of the charge variation of piezoelectric unit (18) is connected.
2. The MEMS fluid gyroscope according to claim 1, wherein the piezoelectric unit (18) comprises a second piezoelectric vibrator (23) or a third piezoelectric vibrator (24), the end of the first microchannel (1) away from the fluid inlet (9) is connected to the second piezoelectric vibrator (23), the end of the second microchannel (2) away from the fluid outlet (13) is connected to the third piezoelectric vibrator (24), the sensor unit comprises a first sensor (20) or a second sensor (26), and the second piezoelectric vibrator (23) is connected to the first sensor (20) through the wire (19); the third piezoelectric vibrator (24) is connected to the second sensor (26) through the lead (19).
3. The MEMS fluid gyroscope according to claim 2, wherein the piezoelectric unit (18) further comprises a piezoelectric vibrator mount (22) for mounting the second piezoelectric vibrator (23) or the third piezoelectric vibrator (24) on the first microchannel (1) or the second microchannel (2).
4. The MEMS fluid gyroscope according to claim 1, characterized in that a second communicating microchannel (10) is provided between the first planar archimedean spiral microchannel (8) and the microcavity (11), and both ends of the second communicating microchannel (10) are respectively communicated with the first planar archimedean spiral microchannel (8) and the microcavity (11).
5. The MEMS fluid gyroscope according to claim 1, characterized in that the upper cover (3) or the lower cover (5) is provided with a second planar archimedean spiral microchannel (28) formed on the upper cover (3) or the lower cover (5) by MEMS process, and both ends of the second planar archimedean spiral microchannel (28) are respectively communicated with the first communicating microchannel (12) and the fluid outlet (13).
6. The MEMS fluid gyroscope of an Archimedes spiral microchannel valveless piezoelectric pump according to claim 5, wherein the first planar Archimedes spiral microchannel (8) is an Archimedes spiral microchannel centered on the fluid inlet (9) and starting in a counterclockwise direction, the second planar Archimedes spiral microchannel (28) is an Archimedes spiral microchannel centered on the fluid outlet (13) and starting in a clockwise direction, the first planar Archimedes spiral microchannel (8) and the second planar Archimedes spiral microchannel (28) are symmetrically arranged on the upper cover (3) or the lower cover (5), and the fluid inlet (9) and the fluid outlet (13) are symmetrically arranged on both sides of a center line of the microcavity (11).
7. The MEMS fluid gyroscope of claim 1, wherein the upper cover (3) or the lower cover (5) is integrally molded by casting PDMS material, and the first planar archimedean spiral microchannel (8) is molded by casting PDMS material on a convex mold having the same shape as the first planar archimedean spiral microchannel (8) after curing, and the convex mold is patterned by SU-8 photoresist.
8. The MEMS fluid gyroscope according to claim 1, wherein the lower cover (5) is provided with a first groove (111), the upper cover (3) is provided with a second groove (112), the first groove (111) and the second groove (112) are hermetically matched to form the microcavity (11), the first piezoelectric vibrator (4) is accommodated in the second groove (112), and the second groove (112) is provided in a step shape.
9. The archimedean spiral microchannel valveless piezoelectric pump-based MEMS fluid gyroscope of claim 8, wherein the micro-cavity (11) is formed on the lower cover (5) by a MEMS process, and the cross-section of the micro-cavity (11) is circular.
10. The Archimedean spiral microchannel valveless piezoelectric pump-based MEMS fluid gyroscope of claim 1, wherein the first piezoelectric vibrator (4), the second piezoelectric vibrator (23) and the third piezoelectric vibrator (24) have the same structure, the first piezoelectric vibrator (4) comprises a substrate (41) and a conductive layer (42) formed on the substrate (41) by sputtering, the conductive layer (42) comprises a metal layer and a piezoelectric function material layer, the piezoelectric function material layer is embedded in the substrate (41), the metal layer is positioned above the piezoelectric function material layer, the substrate (41) is made of silicon material, and the piezoelectric function material layer is made of inorganic piezoelectric material.
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