CN1326090A - Bidirectionally synthesizing jet gyroscope - Google Patents

Abstract

The invention belongs to the technical field of sensors. Two identical synthetic jet flow sources with opposite velocities consisting of a driver diaphragm and a nozzle are used, and one or more pairs of heating thermal sensors are symmetrically arranged on both sides of the centerline of the synthetic jet flow, and the position of the thermal sensors is located at 9-15 times the diameter of the spout. The present invention can smoothly detect angular velocity no matter in the case of uniform angular velocity or non-uniform angular velocity, has simple structure, long service life, can adopt micro-machining technology, is convenient to process, and has low cost. High sensitivity and resolution. The present invention is suitable for application in different occasions, especially in harsh working environments.

Description

Bidirectional Synthetic Jet Gyroscope

The invention belongs to the technical field of sensors.

信息。这意味着在应用于非匀角速度情况时候，上述陀螺仪得不到正确的角速度信息。另外，上述陀螺仪中的关键的部件为泵1，2和流道5，这种结构使得这种陀螺仪的尺寸较大，价格偏高。同时，狭长的流道5使射流速度衰减很快，这将导致陀螺仪的灵敏度和分辨率大大降低。Angular velocity sensors or gyroscopes are widely used in the fields of automobiles, military, civilian products (such as cameras, toys, mice), industrial control, aviation and ships. It is a goal that people have been pursuing to develop a new type of gyroscope with better performance, higher reliability and lower price. Among the devices used to measure angular velocity at present, a common feature is the need for rotating parts. The existence of rotating parts makes the life of the device short and the reliability low. In addition, it also makes micromachining difficult and expensive. US Patent 5012676 proposes a gyroscope with gas jet as the working medium, the schematic diagram of which is shown in Figure 1 . It uses a pump 1, 2 to form a fluid flow through the nozzle 3. This fluid flows through a narrow and long channel 5 and is heated by the heating plate 4 to form a hot fluid, and then forms a jet in the cavity 7 through the nozzle 6, and Shoot onto two thermosensitive sensors 8 symmetrically arranged on the centerline of the cavity. When there is no angular velocity, the jet is not deflected, and the two thermosensitive wires detect the same temperature, but when there is an angular velocity, the jet is deflected, and a temperature difference is formed between the two thermal sensors. This difference contains Angular velocity information, angular velocity can be measured by measuring the temperature difference. The above-mentioned gyroscope has a major disadvantage. Since the jet flow is only in one direction, when it is applied to the case of non-uniform angular velocity, the deflection of the jet flow is affected by the Coriolis force and the tangential force at the same time. Therefore, the two heat-sensitive wires The detected temperature difference contains angular velocity ω and angular acceleration

information. This means that the above-mentioned gyroscope cannot obtain correct angular velocity information when applied to a situation of non-uniform angular velocity. In addition, the key components of the above gyroscope are the pumps 1, 2 and the flow channel 5. This structure makes the gyroscope larger in size and higher in price. At the same time, the narrow and long flow channel 5 makes the velocity of the jet decay rapidly, which will greatly reduce the sensitivity and resolution of the gyroscope.

信息，获得角速度信息。同时具有结构简单、可靠性好、灵敏度和分辨率高、成本低的特点。The purpose of the present invention is to overcome the deficiencies of the prior art, and propose a two-way synthetic jet gyroscope, which uses gas jets as the working medium, and can effectively eliminate angular acceleration in the case of non-uniform angular velocity.

information to obtain angular velocity information. At the same time, it has the characteristics of simple structure, good reliability, high sensitivity and resolution, and low cost.

The present invention proposes a two-way synthetic jet flow gyroscope, which is characterized in that it adopts two completely identical synthetic jet flow sources with opposite speeds consisting of a driver vibrating membrane and a nozzle, and one or more pairs of heating thermal sensors are symmetrically arranged on the On both sides of the center line of the synthetic jet stream, the position of the thermal sensor is 9-15 times away from the diameter of the nozzle.

The present invention can be produced by precision machining or micro-processing technology.

The driver of said synthetic jet is any one of electromagnetic, piezoelectric, electrostatic and other driving methods.

The said synthetic jet flow source includes a shell, a working cavity fixed on the shell, a synthetic jet composed of a driver vibrating membrane and a nozzle, a circuit board with a measuring circuit fixed on one side of the shell and the cavity, symmetrically arranged Multiple return and cooling holes on the jet working cavity.

Working principle and characteristics of the present invention:

First, briefly introduce the concept of synthetic spray. Figure 2 is a schematic diagram of the basic working principle of the synthetic spray. In the figure, there is a cavity 10, one side of the cavity 10 is a film 9, and the other side has a small hole (spout) 11, and the gas periodically enters and flows out of the cavity through the small hole through the periodic vibration of the film. When the gas flows out of the small hole, a shear layer is formed between the outflowing gas and the surrounding static gas, and this layer of vortex will wind up to form a vortex ring 12, which leaves the cavity and moves downstream under the action of self-attraction. At the same time, as the membrane moves back, the gas will be sucked into the cavity from the small hole, and the vortex ring is far away from the cavity at this time, so it is not affected by the suction process. In this way, a series of vortex rings will be formed, and these vortex rings will experience processes such as instability and fragmentation during movement, and finally form turbulent jets 13 near the small holes. This spray has several characteristics: 1) No fluid delivery is required, and the net mass flow rate is zero; 2) Electrical parameter control, the speed of the jet can be adjusted by changing the electrical parameters of the driver. The above characteristics make the synthetic jet can be easily integrated in the measurement of angular velocity, it simplifies the pump device required by the general jet flow, and can be processed by micro-processing technology, thereby greatly reducing the cost.

The schematic diagram of measuring angular velocity by bidirectional synthetic jet gyroscope is shown in Fig.3. 14 in the figure is a two-way synthetic jet flow gyroscope, F _L is centrifugal force, F _K is Coriolis force, V _r is relative to the velocity in the measuring device of the measured object, and ω is the angular velocity to be measured. In the case of uniform angular velocity, F _K only contains the Coriolis force, and an electrical signal proportional to 4ω×V _r can be obtained at this time, which is double the 2ω×V _r of a single jet. In the case of non-uniform angular velocity, because F _K contains Coriolis force and tangential force, as mentioned above, the unidirectional jet gyroscope cannot detect accurately, but for the double-jet of the bidirectional synthetic jet gyroscope in this paper, Coriolis force sprayed on the left $f_{\mathrm{KL}}=-m(\stackrel{.}{\mathrm{\ω}}\×R-2\mathrm{\ω}\×V_r),$ The Coriolis force sprayed on the right is $f_{\mathrm{KR}}=-m(\stackrel{.}{\mathrm{\ω}}\×R+2\mathrm{\ω}\×V_r)$ . In summary: F＝F _KL －F _KR ＝4ω×V _r . Apparently, the dual-jet jets in opposite directions can detect the angular velocity smoothly no matter in the case of uniform angular velocity or non-uniform angular velocity, and at the same time, the sensitivity can be doubled compared with the single-jet gyroscope.

The two-way synthetic jet gyroscope is formed by using the above principles and combining the concept of synthetic jet. Since there are no pumps and narrow and long flow channels, this gyroscope can be processed in two ways, one is precision machining, and the other is micromachining, that is, silicon materials are processed by IC technology. It uses a synthetic jet to generate a jet as a working medium. In the absence of angular velocity, the jet will not deflect, as shown in Figure 4. At this time, one or more pairs of heated heat-sensitive sensors symmetrically arranged in the jet will receive the same impact from the relatively low-temperature airflow, so the temperature is the same and there will be no electrical signal output. When there is an angular velocity, the jet is deflected due to the Coriolis force, as shown in Figure 5. At this time, the impact of the jet flow on the corresponding pair of thermal sensors is different, and a temperature difference will be generated between the two sensors. This temperature difference is proportional to the force of the jet, and the force of the jet contains the information of the angular velocity. , so the angular velocity information can be obtained by measuring the temperature difference.

Features and scope of application of the present invention:

1. Using double-jet cross-firing, it can measure uniform angular velocity and non-uniform angular velocity, and the sensitivity is doubled compared with single-jet gyroscope.

2. Since the synthetic spray device is used as the jet source, the fluid is used as the working medium, and there are no rotating parts, the working life of this gyroscope is relatively long.

3. Synthetic spray is used to form a jet, there is no narrow and long flow channel, the structure is simple, and it is easy to process and manufacture;

4. The jet directly acts on the sensitive device, and the jet velocity is relatively high, so the sensitivity and resolution are high.

5. Due to the mature micro-processing technology of synthetic spray and thermal sensor, the process of manufacturing integrated circuits can be used

(IC technology) Mass production greatly reduces costs, so it is suitable for situations where low cost is required, such as

Such as airbag safety systems and toys used in cars;

6. The present invention is suitable for application in different occasions, especially when the working environment is harsh and long life is required

situation.

Brief description of the drawings:

FIG. 1 is a schematic structural diagram of an existing jet gyroscope.

Fig. 2 is a schematic diagram of the working principle of the synthetic spray of the present invention.

Fig. 3 is a schematic diagram of the angular velocity measurement principle of the present invention.

Fig. 4 is a left-right symmetric view of the jet without angular velocity in the present invention.

Fig. 5 is a diagram showing the deflection of the angular velocity jet in the present invention.

Fig. 6 is a schematic view of the structure of Embodiment 1 using a pair of sensors of the present invention.

Fig. 7 is a schematic structural diagram of Embodiment 2 using two pairs of sensors of the present invention.

The present invention designs two kinds of two-way synthetic jet flow gyroscope embodiments, in conjunction with accompanying drawing, describe in detail as follows:

Embodiment 1 is a two-way synthetic jet gyroscope with a pair of temperature sensors, the structure of which is shown in FIG. 6 . The left and right edges in the figure are completely symmetrical along the centerline of the vibrating membrane, and the left half is used here for illustration. The packaging shell 15 can be cylindrical or square, and the jet working cavity 18 is fixed on the shell 15. On one side of the jet working cavity is a circuit board 16 with a measuring circuit, which is fixed on the shell 15 and the jet working cavity 18 . Up and down symmetrical synthetic jets are arranged on the right side of the jet working cavity 18, and they are composed of a driver vibrating membrane 21, a synthetic jet cavity body 22 and a spout 20. The driver of the vibrating membrane 21 can adopt piezoelectric drive, electrostatic drive or electromagnetic drive, wherein the amplitude of the electromagnetic drive can be relatively large, which is conducive to the formation of high jet velocity. The driver of the vibrating membrane in Embodiment 1 adopts electromagnetic drive, and the working frequency is 500 Hz . The size of the spout 20 can be selected according to needs. Generally speaking, under the condition of the same half-cycle average mass flow rate, the sensitivity and resolution of the angular velocity meter designed with a small-sized spout will be higher than that of a large-sized spout. In the first embodiment The diameter of the spout is 0.5mm, and the heights of the vibrating films 21a and 21b from the center line are both 1mm. In order to detect the jet, two temperature sensors 19a and 19b arranged with the center line of the nozzle 20 as a symmetrical line are fixed on the jet working cavity, and the distance from it to the nozzle 20 is 10 times the diameter of the nozzle in Embodiment 1, that is, the distance The spout is 5mm. The temperature sensor is made of a heating thermistor wire whose temperature is higher than that of the jet. In order to effectively form the jet flow and prevent the temperature in the cavity 18 from rising, the four return and cooling holes 17a-17d are symmetrically arranged on the jet working cavity 18, two of which are on the left side of the heating thermistor wire, and two are arranged on the left side of the heating thermistor wire. on the right. In Embodiment 1, the length of the working cavity is 10 mm, the height is 5 mm, and the diameter of the return and heat dissipation holes is 0.2 mm.

The above-mentioned device mainly generates the jet flow through the synthetic jet composed of 21, 22 and 20, and the jet flow will not be deflected in the absence of angular velocity. At this time, a pair of heated heat-sensitive sensors symmetrically arranged in the jet will receive the same impact from the relatively low-temperature airflow, and there will be no electrical signal output due to the same temperature. When there is an angular velocity, the jet is deflected due to the Coriolis force. At this time, the jet impact on a pair of temperature sensors will be different, and the temperature difference will be generated between the two sensors. This temperature difference is proportional to the Coriolis force, and the Coriolis force contains the information of the angular velocity. Therefore, by measuring the temperature The difference can obtain the information of the angular velocity.

In addition to the arrangement of a pair of temperature sensors shown in Figure 6, the second embodiment is a two-way synthetic jet gyroscope with two pairs of temperature sensors, the structure of which is shown in Figure 7, the temperature sensors are respectively 19a-19d in the figure, other structures It is basically the same as Figure 6, and the working principle is also basically the same, but the detection accuracy is higher. The length of one side of the working cavity in the second embodiment is 9mm, the height is 4mm, the backflow and heat dissipation aperture is 0.2mm, the driver of the vibrating film is piezoelectric drive, the vibration frequency is 2000Hz, the diameter of the spout is 0.3mm, the vibrating film 21a and The height of 21b from the center line is 0.5mm, and the distance between the temperature sensor and the nozzle is 14 times the diameter of the nozzle, that is, 5.2mm.

In addition to the above two embodiments, multiple pairs of sensors can also be arranged symmetrically, which will help improve detection accuracy and reduce errors.

Claims (4)

1. A two-way synthetic jet flow gyroscope is characterized in that, adopting two opposite identical synthetic jet flow sources made of a driver vibrating membrane and a spout, one or more pairs of heating thermosensitive sensors are symmetrically arranged on the On both sides of the centerline of said synthetic jet stream, the position of the thermal sensor is 9-15 times away from the diameter of the nozzle. 2. The two-way synthetic jet gyroscope as claimed in claim 1, characterized in that, it is made by precision machining or micromachining technology. 3. The two-way synthetic jet gyroscope as claimed in claim 1, characterized in that, the driver of said synthetic jet is any one of electromagnetic, piezoelectric, electrostatic and other drive methods. 4. bidirectional synthetic jet gyro as claimed in claim 1, is characterized in that, said synthetic jet source comprises a shell, is fixed on the working cavity on the shell, the synthetic spray that driver vibrating membrane and spout constitute, A circuit board with a measuring circuit fixed on one side of the housing and the cavity, and multiple return and heat dissipation holes symmetrically arranged on the jet working cavity.

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