A space microelectromechanical thruster integrating measurement and control

Abstract

The present invention relates to an integrated measurement and control space microelectromechanical thruster, which comprises a device body and a control module connected to the device body. The device body includes a flow control area, a flow monitoring area, and a heating area arranged in sequence. A gas flow channel penetrating the flow control area, the flow monitoring area, and the heating area is provided in the device body. One end of the gas flow channel located in the flow control area is a gas inlet, and the other end located in the heating area is a gas outlet. The gas inlet is connected to a gas source. Compared with the prior art, the present invention has the following advantages: the device body is provided with a flow control area, a flow monitoring area, and a heating area, and the control, monitoring, and heating of the gas flow can be realized only through the device body, and the overall structure is small in volume; high-frequency switching actions are realized through the deformation of the piezoelectric film and the flexible film, stable and continuous gas flow output is achieved, and the response time is short; the heating module includes a heating resistor and a suspended structure, which prevents heat from diffusing into the chip interior, and high stability and reliability are achieved.

Description

Technical Field

[0001] The present invention relates to a thruster, and in particular to an integrated measurement and control space microelectromechanical thruster. Background Art

[0002] Microthrusters are mainly applied to various space missions such as satellite attitude control, orbit transfer, and drag compensation. Microthrusters can be roughly classified according to different working principles: (1) Pressure-accelerated thrusters, including chemical micropropulsion, cold gas propulsion, new electrothermal propulsion, etc., which are characterized by relatively large thrust and a large thrust adjustment range; (2) Electrostatic-accelerated thrusters, including microcathode arc thrusters, field emission electric thrusters, ionic liquid thrusters, etc., which are characterized by relatively high specific impulse.

[0003] After retrieval, the application publication number CN113110625A discloses a colloidal micropropulsion storage and supply system, a flow closed-loop feedback control method and system, specifically discloses: including a storage and supply system, a flow sensor and a control system. The present invention realizes propellant supply by using devices such as a diaphragm tank, a piezoelectric microvalve and volume compensation, and integrates a thermal temperature difference type flow sensor in the pipeline of the micropropulsion storage and supply system to realize real-time detection of propellant flow. Further, a feedback control signal can be output through a PID controller to control the magnitude and frequency of the voltage applied to the microvalve to realize feedback adjustment of the flow rate. However, the thrust range of this system is small, the measurement accuracy is low and the response is slow.

[0004] Therefore, how to design a thruster with a wide thrust adjustment range, high precision and fast response is a technical problem to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide an integrated measurement and control space microelectromechanical thruster to overcome the defects of the existing technology such as small thrust range, low measurement accuracy and slow response.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to one aspect of the present invention, there is provided an integrated measurement and control space microelectromechanical thruster, including a device body and a control module connected to the device body. The device body includes a flow control area, a flow monitoring area and a heating area arranged in sequence. A gas flow channel is provided in the device body and penetrates through the flow control area, the flow monitoring area and the heating area. One end of the gas flow channel located in the flow control area is a gas inlet, and the other end located in the heating area is a gas outlet. The gas inlet is connected to a gas source.

[0008] As a preferred technical solution, a piezoelectric film and a flexible film are provided in the flow control area. The flexible film is installed on one side of the gas flow channel and has a cavity between it and the device body. The piezoelectric film is attached to the surface of the flexible film and is located within the cavity. The piezoelectric film is connected to a control module, and the control module controls the opening or closing of the gas flow channel by the piezoelectric film.

[0009] As a preferred technical solution, the controller controls the gap between the side of the gas flow channel where the piezoelectric film and the flexible film are located and the other side.

[0010] As a preferred technical solution, the flexible film is made of polyimide material.

[0011] As a preferred technical solution, the piezoelectric film is prepared by physical sputtering.

[0012] As a preferred technical solution, a temperature sensor and a first heating module are provided in the flow monitoring area, both of which are installed on one side of the gas flow channel. There are two temperature sensors, and the first heating module is installed between the two temperature sensors.

[0013] As a preferred technical solution, a second heating module is provided in the heating area. The second heating module is installed on one side of the gas flow channel, and the heating power density of the second heating module is 0 - 3 mW / um. 2 。

[0014] As a preferred technical solution, the control module includes a control circuit. The control circuit is embedded in the device body between the flow monitoring area and the heating area and is respectively connected to the temperature sensor, the first heating module, and the second heating module. The temperature sensor, the first heating module, and the second heating module all include nitride films manufactured by physical sputtering.

[0015] As a preferred technical solution, the first heating module and the second heating module include a heating resistor and a suspended structure. The heating resistor is manufactured by micro-nano processing technology. The suspended structure is located between the heating resistor and the device body and is manufactured by anisotropic deep etching and controllable lateral etching.

[0016] As a preferred technical solution, the flow control area, the flow monitoring area, and the heating area are all manufactured by MEMS manufacturing technology.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) The device body of the present invention is provided with a flow control area, a flow monitoring area, and a heating area. The control, monitoring, and heating of the gas flow can be realized only through the device body, and the overall structure is small in volume.

[0019] 2) The present invention performs high-frequency switching actions through the deformation of the piezoelectric thin film and the flexible film, achieving stable and continuous gas flow output with a short response time. The piezoelectric thin film is prepared by physical sputtering, and the flexible film is made of polyimide material, realizing highly reliable closure of the piezoelectric thin film and the flexible film.

[0020] 3) The present invention measures the gas flow by the temperature difference method. By heating in the middle and measuring temperatures on both sides, it monitors the temperature difference caused by the flowing gas and calculates the gas flow rate.

[0021] 4) The first heating module and the second heating module of the present invention include heating resistors and suspended structures. After preparing the heating resistors using micro-nano processing technology, the suspended structures are prepared through anisotropic deep etching and controllable lateral etching to prevent heat from diffusing into the chip interior, achieving high stability and reliability. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of an integrated measurement and control space micro-electro-mechanical thruster of the present invention;

[0023] Figure 2 It is a schematic diagram of the array arrangement structure of the present invention;

[0024] As indicated by the reference numerals in the figure:

[0025] 1. Flow control area, 10. Piezoelectric thin film, 11. Flexible film, 2. Flow monitoring area, 20. Temperature sensor, 21. First heating module, 3. Heating area, 30. Second heating module, 4. Gas flow channel, 40. Gas inlet, 41. Gas outlet, 5. Control circuit. Detailed Embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] As Figure 1 shown, the present invention provides an integrated measurement and control space micro-electro-mechanical thruster, including a device body and a control module connected to the device body. The present invention realizes continuously adjustable high-resolution micro-flow control; realizes accurate monitoring and feedback control of the gas working medium flow rate in a rarefied gas environment.

[0028] The device body includes a flow control area 1, a flow monitoring area 2, and a heating area 3 arranged in sequence. There is also a gas flow channel 4 running through the flow control area 1, the flow monitoring area 2, and the heating area 3 within the device body. One end of the gas flow channel 4 in the flow control area 1 is a gas inlet 40, and the other end in the heating area 3 is a gas outlet 41. The gas inlet 40 is connected to a gas source.

[0029] The flow control area 1 is provided with a piezoelectric film 10 and a flexible film 11. The flexible film 11 is installed on one side of the gas flow channel 4 and has a cavity between it and the device body. The piezoelectric film 10 is attached to the surface of the cavity between the flexible film 11 and the device body, and can control the opening and closing of the gas channel through deformation; the piezoelectric film 10 is connected to a control module, and the control module controls the piezoelectric film 10 to close or open the gas flow channel 4 by controlling the gap between the side where the piezoelectric film 10 and the flexible film 11 are located and the other side on the gas flow channel 4. Through high-frequency switching actions, stable and continuous gas flow output is achieved.

[0030] The flexible film 11 is made of polyimide material. The piezoelectric film 10 is prepared by physical sputtering to achieve highly reliable closing of the switching valve.

[0031] As Figure 2 shown, high-frequency switching actions are performed through the deformation of the piezoelectric film 10 and the flexible film 11 to achieve stable and continuous gas flow output. When the present invention is arranged in an array, the dynamic range can be adjusted; the structure of the flow control area 1 and the switching frequency are designed and optimized through fluid structure simulation and model simulation to achieve adjustable vibration frequencies of 0 - 40 kHz for the piezoelectric film 10 and the flexible film 11, and the response time ≤ 25 ms.

[0032] The control module includes a control circuit 5. The control circuit 5 is embedded in the device body between the flow monitoring area 2 and the heating area 3 for the integrated control of the system unit and the reading and processing of temperature signals.

[0033] In the flow monitoring area 2, a temperature sensor 20 and a first heating module 21 are both installed on one side of the gas flow channel 4. The temperature sensor 20 and the first heating module 21 are both connected to the control circuit 5. There are two temperature sensors 20, and the first heating module 21 is installed between the two temperature sensors 20 for heating the gas working medium. The temperature sensor 20 is used to monitor the temperature difference of the gas working medium before and after passing through the first heating module 21. The gas flow is measured by the temperature difference method. By heating in the middle and measuring temperatures on both sides, the temperature difference caused by the gas flowing through is monitored, and the gas flow is calculated.

[0034] The differential temperature method is used to measure the gas flow rate. By heating in the middle and measuring the temperature at both sides, the temperature difference caused by the flowing gas is monitored, and the gas flow rate is calculated. CMOS technology is adopted for integrated control, temperature reading and signal processing functions, and optimization and adjustment are carried out according to the heat conduction model of rarefied gas to achieve high-precision temperature measurement of the differential temperature sensor; an on-chip automatic temperature control negative feedback system composed of temperature sensing, heating resistance and integrated circuit control is established to achieve linear and precise heating of rarefied gas and reduce the influence of heating temperature drift on flow measurement. The temperature control range of the flow monitoring area 2 is realized: 30~100°C, and the differential temperature accuracy is: 0.05°C.

[0035] The heating zone 3 is provided with a second heating module 30 installed on one side of the gas flow channel 4. The second heating module 30 is connected to the control circuit 5, and the heating power density of the second heating module 30 is 0~3mW / um 2 。

[0036] The temperature sensor 20, the first heating module 21 and the second heating module 30 all include nitride films with high resistance and low temperature coefficient prepared by reactive physical sputtering. The first heating module 21 and the second heating module 30 are thin-film heating modules to heat the gas working medium by Joule heat.

[0037] The piezoelectric thin film 10 and the flexible film 11 in the flow control area 1, the temperature sensor 20 and the first heating module 21 in the flow monitoring area 2, and the second heating module 30 in the heating area 3 are all manufactured by MEMS manufacturing process.

[0038] The MEMS manufacturing process (Microelectromechanical systems, MEMS) is a general term for microstructural processing technologies from the nanoscale to the millimeter scale. In a broad sense, the MEMS manufacturing process has a very rich variety of methods and almost involves various modern processing technologies. It originated from semiconductor and microelectronics processes and is a microfabrication technology that uses lithography, epitaxy, thin film deposition, oxidation, diffusion, implantation, sputtering, evaporation, etching, dicing and packaging as basic process steps to manufacture complex three-dimensional shapes.

[0039] The first heating module 21 and the second heating module 30 adopt a suspended structure to reduce heat transfer dissipation; the structures of the first heating module 21 and the second heating module 30 are reasonably arranged according to the gas channel and structure to control heat dissipation and improve reliability. The heating zone 3 can achieve an adjustable heating power of 0~3mW / um2, and cooperate with the detection of the gas working medium flow rate in the flow monitoring area 2 to carry out feedback control of the Joule heat heating of the second heating module 30. After preparing the heating resistance using micro-nano processing technology, a suspended structure is prepared through anisotropic deep etching and controllable lateral etching to prevent heat from diffusing into the chip interior and ensure high stability and reliability.

[0040] Integrated whole-wafer processing and direct wafer-to-wafer bonding technology are adopted to achieve the integrated processing and laminated stacking packaging of various key components. The integration of each device adopts a highly reliable packaging method of multi-layer silicon wafer bonding. In addition to the devices, microchannels and micro-nozzles need to be prepared in advance on the silicon wafer through micro-nano processing technology, and the minimum aperture can reach the single-micron level.

[0041] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A measurement and control integrated space microelectromechanical thruster, characterized in that, It includes a device body and a control module connected to the device body. The device body includes a flow control area (1), a flow monitoring area (2), and a heating area (3) arranged in sequence. A gas flow channel (4) runs through the flow control area (1), the flow monitoring area (2), and the heating area (3) inside the device body. One end of the gas flow channel (4) in the flow control area (1) is a gas inlet (40), and the other end in the heating area (3) is a gas outlet (41). The gas inlet (40) is connected to a gas source; The flow control area (1) is provided with a piezoelectric film (10) and a flexible film (11). The flexible film (11) is installed on one side of the gas flow channel (4) and has a cavity between it and the device body. The piezoelectric film (10) is attached to the surface of the flexible film (11) and is located inside the cavity; the piezoelectric film (10) is connected to the control module, and the control module controls the piezoelectric film (10) to close or open the gas flow channel (4); The piezoelectric film (10) is prepared by physical sputtering; Inside the flow monitoring area (2), a temperature sensor (20) and a first heating module (21) are both installed on one side of the gas flow channel (4). There are two temperature sensors (20), and the first heating module (21) is installed between the two temperature sensors (20); The first heating module (21) includes a heating resistor and a suspended structure. The heating resistor is manufactured by micro-nano processing technology, and the suspended structure is located between the heating resistor and the device body and is manufactured by anisotropic deep etching and controllable lateral etching.

2. The integrated measurement and control space microelectromechanical thruster according to claim 1, wherein The control module controls the gap between one side and the other side of the piezoelectric film (10) and the flexible film (11) on the gas flow channel (4).

3. The integrated measurement and control space micro-electromechanical thruster according to claim 1, characterized in that, The flexible film (11) is made of polyimide material.

4. The integrated measurement and control space micro-electromechanical thruster according to claim 1, characterized in that, The described heating zone (3) is provided with a second heating module (30), the second heating module (30) is installed on one side of the gas flow channel (4), and the heating power density of the second heating module (30) is 0 to 3 mW / um 2 .

5. A measurement and control integrated space microelectromechanical thruster according to claim 4, characterized in that, The control module includes a control circuit (5). The control circuit (5) is embedded in the device body between the flow monitoring area (2) and the heating area (3) and is respectively connected to the temperature sensor (20), the first heating module (21), and the second heating module (30); the temperature sensor (20), the first heating module (21), and the second heating module (30) all include nitride films manufactured by physical sputtering.

6. The integrated measurement and control space microelectromechanical thruster according to claim 4, characterized in that, The second heating module (30) includes a heating resistor and a suspended structure. The heating resistor is manufactured by micro-nano processing technology, and the suspended structure is located between the heating resistor and the device body and is manufactured by anisotropic deep etching and controllable lateral etching.

7. The integrated measurement and control space micro-electromechanical thruster according to claim 1, characterized in that, The flow control area (1), the flow monitoring area (2), and the heating area (3) are all manufactured by MEMS manufacturing technology.

Images