A micro-cow level hybrid propulsion system and method based on gas working substance

Abstract

The present application relates to the technical field of spacecraft propulsion system, and more particularly to a micro-newton hybrid mode propulsion system and method based on gas working substance. The system comprises a gas storage unit, a gas supply unit, a thruster unit and a propulsion system driving and control unit. The gas storage unit adopts symmetrically arranged high-pressure gas cylinders connected through high-pressure isolation valves, and in combination with the automatic balancing strategy of the control unit, effectively solves the problem of on-orbit centroid drift. The gas supply unit includes parallel cold gas propulsion branches and electric propulsion branches, and each branch adopts a mechanical pressure reducer to eliminate vibration and noise caused by electromagnetic valve action from the source, realizing super-static operation of the system. The propulsion system driving and control unit controls the micro-newton cold gas thruster and the micro-newton electric thruster to work alone or in cooperation according to the distribution strategy based on the thrust critical point, realizing the optimal comprehensive efficiency of high precision and high specific impulse in the full thrust range, and being suitable for ultra-high precision space scientific exploration missions.

Description

Technical Field

[0001] This invention relates to the field of spacecraft propulsion system technology, and in particular to a micro-Newton level hybrid propulsion system and method based on a gaseous working fluid. Background Technology

[0002] Cutting-edge scientific missions such as space gravitational wave detection and high-precision astrometry have placed unprecedented demands on spacecraft platforms for "ultra-precision, ultra-stability, and ultra-quietness," requiring their propulsion systems to provide high-precision, low-noise thrust at the micro-Newton level or even sub-micro-Newton level.

[0003] Currently, micro-Newton (MNY) propulsion technology mainly employs two approaches: cold gas propulsion and electric propulsion. MNY-level cold gas propulsion offers low thrust and noise, and high control precision, but its specific impulse is relatively low (approximately 60 s), limiting spacecraft lifespan. MNY-level electric propulsion offers high specific impulse (up to 1000 s or more) and good fuel economy, but its accuracy and stability at extremely low thrust levels face challenges.

[0004] Existing technologies attempt to combine the two. For example, Chinese patent application CN116513490 discloses a xenon propellant dual-mode propulsion system, which achieves the sharing of propellant and some modules, but does not solve the problem of center-of-gravity drift caused by uneven propellant consumption at the system level, nor does it propose a refined thrust allocation strategy for optimal efficiency across the entire thrust range. Chinese patent application CN115355145A uses a gas field ionization thruster as a performance enhancement for the cold gas thruster, sharing the original propulsion system's storage and supply to achieve dual-mode space propulsion. While retaining the original cold gas propulsion's high thrust and wide range, the integrated electric thruster improves the thruster's specific impulse, increasing it from 60s to over 1000s, effectively improving propellant utilization and extending the thruster's on-orbit life. However, it does not solve the problem of center-of-gravity drift caused by uneven propellant consumption at the system level, and faces challenges in accuracy and stability at extremely low thrust.

[0005] Therefore, there is an urgent need in this field for an intelligent hybrid propulsion system that can deeply integrate the advantages of air and electric propulsion, and can autonomously maintain a stable center of gravity and achieve ultra-quiet operation. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a micro-Newton level hybrid propulsion system and method based on a gaseous working fluid. This system can achieve optimal efficiency across the entire thrust range, automatically maintain center of mass stability, and ensure ultra-quiet operation.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a micro-Newton level hybrid propulsion system based on a gaseous working fluid, characterized in that it comprises:

[0008] A gas storage unit for storing a high-pressure gas working medium includes at least one first high-pressure gas cylinder and at least one second high-pressure gas cylinder arranged symmetrically, and a high-pressure isolation valve connected between the first high-pressure gas cylinder and the second high-pressure gas cylinder.

[0009] A gas supply unit, connected to a gas storage unit, is used to reduce pressure and regulate the flow of high-pressure gas working fluid. The gas supply unit includes a first supply branch and a second supply branch arranged in parallel and symmetrically. A first pressure reducer and a second pressure reducer are respectively provided in the first supply branch and the second supply branch. The first pressure reducer and the second pressure reducer are both mechanical pressure reducers.

[0010] The thruster unit, connected to the gas supply unit, is used to eject the working fluid to generate thrust. The thruster unit includes at least one micronewton-level cold gas thruster connected to a first supply branch and at least one micronewton-level electric thruster connected to a second supply branch.

[0011] The propulsion system drive and control unit is electrically connected to the gas storage unit, gas supply unit, and thruster unit;

[0012] The propulsion system drive and control unit is configured as follows:

[0013] It receives thrust commands and, according to a preset thrust distribution strategy based on the thrust critical point, selectively controls the micro-Newton level cold gas thruster and the micro-Newton level electric thruster to work individually or in combination.

[0014] The pressure in the first and second high-pressure gas cylinders is monitored. When the pressure difference between the two reaches a preset threshold, the high-pressure isolation valve is opened to balance the working fluid.

[0015] Optionally, a buffer gas container is also provided downstream of the first pressure reducer in the first supply branch;

[0016] A flow controller is also provided downstream of the second pressure reducer in the second supply branch.

[0017] Optionally, a first high-pressure throttling orifice and a second high-pressure throttling orifice are respectively provided in the upstream pipelines of the first pressure reducer and the second pressure reducer.

[0018] Optionally, a first low-pressure throttling orifice and a second low-pressure throttling orifice are respectively provided in the inlet pipes of the micro-Newton level cold air thruster and the micro-Newton level electric thruster.

[0019] Optionally, the downstream of the buffer gas container in the first supply branch and the downstream of the flow controller in the second supply branch are connected via a low-pressure isolation valve, which is electrically connected to the propulsion system drive and control unit.

[0020] Optionally, the first high-pressure throttling orifice and the second high-pressure throttling orifice have the same diameter, and their diameters are... Satisfy the following formula:

[0021]

[0022] in, The flow coefficient of the high-pressure throttling orifice is obtained through experimental calibration; The rated filling pressure of the high-pressure gas cylinder; This refers to the density of the gaseous working medium at the rated filling pressure and design temperature.

[0023] The first low-pressure throttling orifice and the second low-pressure throttling orifice have the same diameter, and their diameters are... Satisfy the following formula:

[0024]

[0025] in, The flow coefficient of the low-pressure throttling orifice was obtained through experimental calibration. To buffer the outlet pressure of the gas container; This refers to the density of the gaseous working medium at the rated outlet pressure and design temperature of the buffer gas container.

[0026] Optionally, the working gas is xenon.

[0027] Secondly, the present invention also provides a micro-Newton level hybrid propulsion method based on a gaseous working fluid, comprising the following steps: A micro-Newton level hybrid propulsion system employing any implementation of the first aspect is also provided.

[0028] Receive thrust command;

[0029] According to the preset thrust distribution strategy based on the thrust critical point, the micro-Newton level cold gas thruster and the micro-Newton level electric thruster are selectively controlled to work alone or in combination to output the target thrust.

[0030] Monitor the pressure inside the first and second high-pressure gas cylinders, which are symmetrically arranged.

[0031] When the pressure difference between each high-pressure gas cylinder reaches a preset threshold, the high-pressure isolation valve is opened to balance the working fluid in each high-pressure gas cylinder.

[0032] Optionally, the thrust distribution strategy is based on the thrust critical point, including:

[0033] The minimum thrust critical point corresponds to the minimum stable output thrust of a micro-Newton level cold gas thruster.

[0034] The first thrust critical point corresponds to the minimum stable output thrust of a micro-Newton-level electric thruster.

[0035] The second thrust critical point corresponds to the maximum stable output thrust of the micro-Newton electric thruster.

[0036] The maximum thrust critical point corresponds to the maximum stable output thrust of a micro-Newton level cold gas thruster.

[0037] Optionally, selectively controlling the micro-Newton level cold gas thruster and the micro-Newton level electric thruster to operate individually or in combination specifically includes:

[0038] When the commanded thrust is less than the first thrust critical point, the micro-Newton level cold gas thruster is controlled to work.

[0039] When the commanded thrust is between the first thrust critical point and the second thrust critical point, the micro-Newton level cold gas thruster and the micro-Newton level electric thruster are controlled to work together.

[0040] When the commanded thrust is greater than the second thrust critical point, the micro-Newton level cold gas thruster is controlled to work, or the micro-Newton level cold gas thruster and the micro-Newton level electric thruster are controlled to work in coordination.

[0041] The above-described technical solution of the present invention has the following advantages:

[0042] This invention provides a micro-Newton level hybrid propulsion system based on a gaseous working fluid. The core of this system includes two symmetrically arranged high-pressure gas cylinders and a high-pressure isolation valve connecting them (for maintaining center-of-gravity stability), two parallel supply branches (leading to a cold gas thruster and an electric thruster respectively, with each branch employing a mechanical pressure reducer for ultra-quiet operation), and an intelligent control unit. This control unit can intelligently allocate the operation of the two thrusters according to thrust commands and automatically open the high-pressure isolation valve to balance the working fluid when the pressures of the two gas cylinders are uneven. Through the coordination of the symmetrical gas cylinders, the high-pressure isolation valve, and the propulsion system drive and control unit, this system solves the problem of autonomously maintaining center-of-gravity stability. By employing mechanical pressure reducers at key pressure adjustment points throughout the system, the periodic vibrations and electromagnetic interference generated by the solenoid valve operation are fundamentally eliminated, significantly improving the system's quietness level and providing a core guarantee for achieving ultra-quiet operation.

[0043] This invention provides a micro-Newton-level hybrid propulsion method based on the aforementioned system. The core of this method is defining an intelligent thrust allocation strategy based on the thrust critical point: when the commanded thrust is very low and high control precision is required, only a high-precision cold gas thruster is used; when the commanded thrust is within the efficient range of the electric thruster and the control precision requirement is relatively low, only a high-specific-impulse electric thruster is used; when greater thrust is required, or when both high thrust and high control precision are needed simultaneously, a cold gas thruster is used, or both are used in combination. This method achieves intelligent operation of "using the most suitable propulsion mode in the appropriate thrust range." It transforms the performance potential of the hardware into optimal overall system efficiency, enabling the ultra-high precision and stability of cold gas propulsion in the sub-micro-Newton thrust range, and leveraging the high specific impulse of electric propulsion to significantly save fuel in the micro-Newton thrust range, thereby significantly widening the thrust range and maximizing overall efficiency throughout the entire mission cycle. Attached Figure Description

[0044] The accompanying drawings are provided for illustrative purposes only, and the proportions and quantities of the components in the drawings may not be consistent with the actual product.

[0045] Figure 1 This is a structural block diagram of a micro-Newton level hybrid propulsion system based on a gaseous working fluid, as described in an embodiment of the present invention.

[0046] In the picture:

[0047] 1: Gas storage unit;

[0048] 1-1: First high-pressure gas cylinder;

[0049] 1-2: Second high-pressure gas cylinder;

[0050] 1-3: First high-pressure sensor;

[0051] 1-4: Second high-pressure sensor;

[0052] 1-5: First air intake and exhaust valve;

[0053] 1-6: Second gas supply and exhaust valve;

[0054] 1-7: First high-pressure throttling orifice;

[0055] 1-8: Second high-pressure throttling orifice;

[0056] 1-9: First high-pressure self-locking valve;

[0057] 1-10: Second high-pressure self-locking valve;

[0058] 1-11: High-pressure isolation valve;

[0059] 2: Gas supply unit;

[0060] 2-1: First pressure reducer;

[0061] 2-2: Second pressure reducer;

[0062] 2-3: First gas test interface;

[0063] 2-4: Second gas test interface;

[0064] 2-5: Buffer gas capacity;

[0065] 2-6: Flow controller;

[0066] 2-7: First low-pressure sensor;

[0067] 2-8: Second low-pressure sensor;

[0068] 2-9: First low-pressure throttling orifice;

[0069] 2-10: Second low-pressure throttling orifice;

[0070] 2-11: First filter;

[0071] 2-12: Second filter;

[0072] 2-13: Low-pressure isolation valve;

[0073] 3: Thrust unit;

[0074] 3-1: Micro-Newton level cold air thruster;

[0075] 3-2: Micro-Newton level electric thruster;

[0076] 4: Propulsion system drive and control unit;

[0077] 4-1: First push circuit box;

[0078] 4-2: Second push circuit box. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0080] like Figure 1As shown, this embodiment of the invention provides a micro-Newton level hybrid propulsion system based on a gaseous working fluid. The system includes a gas storage unit 1, a gas supply unit 2, a thruster unit 3, and a propulsion system drive and control unit 4.

[0081] The gas storage unit 1 includes a first high-pressure gas cylinder 1-1 and a second high-pressure gas cylinder 1-2 symmetrically arranged on both sides of the spacecraft's center of mass, and a high-pressure isolation valve 1-11 connecting the two. This symmetrical arrangement is the structural basis for maintaining the stability of the center of mass.

[0082] The gas supply unit 2 is connected to the gas storage unit 1 and includes a first supply branch (cold-push branch) and a second supply branch (electric-push branch) arranged in parallel. The first and second supply branches are respectively equipped with a first pressure reducer 2-1 and a second pressure reducer 2-2, both of which are mechanical pressure reducers. The mechanical pressure reducer utilizes feedback and balance from internal diaphragms, springs, and other mechanical structures to achieve pressure stabilization, fundamentally avoiding vibration and noise caused by solenoid valve operation, thus achieving "ultra-quiet operation." More preferably in this embodiment, the mechanical pressure reducer adopts a two-stage series structure, with the first stage being a pressure reducing module and the second stage a pressure stabilizing module, which can make the airflow more stable and achieve a better "ultra-quiet operation" effect. In this embodiment, the first and second supply branches are arranged symmetrically.

[0083] The thruster unit 3 is connected to the gas supply unit 2, and includes a micro-Newton level cold gas thruster 3-1 connected to the first supply branch and a micro-Newton level electric thruster 3-2 connected to the second supply branch. In this embodiment, the micro-Newton level cold gas thruster 3-1 and the micro-Newton level electric thruster 3-2 can be based on existing technology.

[0084] The propulsion system drive and control unit 4 is electrically connected to all the aforementioned units. It is configured to perform two core functions: First, receiving thrust commands and intelligently selecting, based on a preset thrust distribution strategy using a thrust critical point, whether to operate the cold gas thruster 3-1, the electric thruster 3-2, or both in tandem. Second, real-time monitoring of the pressure in the first high-pressure gas cylinder 1-1 and the second high-pressure gas cylinder 1-2. After a period of on-orbit operation, a difference in the remaining pressure in the two high-pressure gas cylinders develops. This difference is monitored by the first high-pressure pressure sensor 1-3 and the second high-pressure pressure sensor 1-4, which are connected to each cylinder, and the signals are transmitted to the propulsion system drive and control unit. When the pressure difference reaches a preset threshold (e.g., 0.5 MPa), the high-pressure isolation valve 1-11 is opened, allowing the working fluid to flow from the high-pressure side cylinder to the low-pressure side cylinder until pressure equilibrium is reached. The valve is then closed to maintain the stability of the system's center of mass.

[0085] This embodiment constitutes a complete solution. By coordinating symmetrical gas cylinders, high-pressure isolation valves, and the propulsion system drive and control unit, the problem of autonomously maintaining a stable center of gravity is solved. Through the use of mechanical pressure reducers at key pressure regulation points throughout the system, the periodic vibrations and electromagnetic interference generated by the solenoid valve's operation are fundamentally eliminated, significantly improving the system's quietness level and providing a core guarantee for achieving ultra-quiet operation.

[0086] See one example. Figure 1 A first high-pressure self-locking valve 1-9 and a second high-pressure self-locking valve 1-10 are respectively installed upstream of the first pressure reducer in the first supply branch and upstream of the second pressure reducer in the second supply branch to control the on / off state of the air passage when needed. The first high-pressure self-locking valve 1-9 and the second high-pressure self-locking valve 1-10 are electrically connected to the propulsion system drive and control unit.

[0087] In this embodiment, the high-pressure gas cylinder is a gas cylinder that can be refilled on the ground. When the propulsion system is refilled on the ground, high-pressure gas is added to the first high-pressure gas cylinder 1-1 and the second high-pressure gas cylinder 1-2 through the first gas filling and emptying valve 1-5 and the second gas filling and emptying valve 1-6, respectively.

[0088] See one example. Figure 1 The first supply branch (cold thrust branch) includes a first pressure reducer 2-1 and a buffer gas container 2-5 connected in sequence. The first pressure reducer 2-1 reduces the pressure of the working fluid (e.g., 15 MPa) from the high-pressure gas cylinder to a lower and stable intermediate pressure (e.g., 0.15 MPa). The buffer gas container 2-5 absorbs pressure fluctuations, providing an extremely stable inlet pressure environment for the downstream cold gas thruster 3-1, which is crucial for achieving high-precision thrust output. The second supply branch (electric thrust branch) includes a second pressure reducer 2-2 and a flow controller 2-6 connected in sequence. The second pressure reducer 2-2 also performs primary pressure reduction. The flow controller 2-6 (usually piezoelectric driven) performs secondary precise regulation of the working fluid, providing a constant and minute flow rate to the electric thruster 3-2, ensuring its stable ionization and operation. In this example, by designing dedicated and refined supply paths for thrusters with different characteristics, the cold thrust branch focuses on pressure stability by setting the first pressure reducer 2-1 and buffer gas container 2-5, while the electric thrust branch focuses on flow accuracy by setting the second pressure reducer 2-2 and flow controller 2-6. This allows both types of thrusters to operate under their respective optimal conditions, thereby maximizing the advantages of the hybrid mode at the system level and taking into account both high precision and high specific impulse.

[0089] To facilitate ground testing, a first gas test interface 2-3 is provided downstream of the first pressure reducer in the first supply branch; and a second gas test interface 2-4 is provided downstream of the second pressure reducer in the second supply branch.

[0090] To facilitate downstream pressure monitoring, a first low-pressure sensor 2-7 is installed on the first supply branch. A second low-pressure sensor 2-8 is installed on the second supply branch.

[0091] To prevent impurities that may be present in the gas from entering the propulsion system, in one example, a first filter 2-11 is provided upstream of the micro-Newton level cold gas thruster 3-1, and a second filter 2-12 is provided upstream of the micro-Newton level electric thruster 3-2.

[0092] To further reduce vibration noise, see Figure 1 In one example, a first high-pressure throttling orifice 1-7 is provided in the upstream pipeline of the first pressure reducer 2-1, and a second high-pressure throttling orifice 1-8 is provided in the upstream pipeline of the second pressure reducer 2-2. The high-pressure throttling orifice, as a pre-stage protection for the pressure reducer, effectively suppresses the airflow impact generated when the high-pressure valve is opened, protecting the precision mechanical pressure reducer and further reducing system noise, thus enhancing the "ultra-quiet operation" effect.

[0093] To further reduce vibration noise, see Figure 1 In one example, a first low-pressure throttling orifice 2-9 is provided in the inlet pipe of the micro-Newton level cold gas thruster 3-1, and a second low-pressure throttling orifice 2-10 is provided in the inlet pipe of the micro-Newton level electric thruster 3-2. The low-pressure throttling orifice, acting as a terminal noise suppressor, effectively filters out pressure fluctuations transmitted from upstream to the thruster, significantly reducing thrust noise. This is a key terminal measure for achieving sub-micro-Newton level ultra-high precision thrust and ultra-quiet operation.

[0094] In one example, the orifice structure is quantitatively defined. The first high-pressure orifice 1-7 and the second high-pressure orifice 1-8 have the same orifice diameter, and their diameters are... Satisfy the following formula:

[0095]

[0096] in, The flow coefficient of the high-pressure throttling orifice is obtained through experimental calibration; This refers to the rated filling pressure of the high-pressure gas cylinder. This refers to the density of the gaseous working medium at the rated filling pressure and design temperature.

[0097] The first low-pressure throttling orifice 2-9 and the second low-pressure throttling orifice 2-10 have the same orifice diameter. Satisfy the following formula:

[0098]

[0099] in, The flow coefficient of the low-pressure throttling orifice was obtained through experimental calibration. To buffer the outlet pressure of the gas container; This refers to the density of the gaseous working medium at the rated outlet pressure and design temperature of the buffer gas. The above formula is used to quantitatively design the high-pressure and low-pressure throttling orifices, ensuring that they function as dampers and stabilizers while controlling pressure loss within the system's allowable range. This achieves an optimal balance between stability and efficiency that is predictable and reproducible.

[0100] In this embodiment, the gaseous working medium stored in the gas storage unit 1 is preferably xenon. Xenon has the advantages of large molecular weight (which is beneficial for cold propulsion) and easy ionization (which is beneficial for electric propulsion). As a unified working medium, it realizes the high integration of the system, simplifies the architecture, and reduces costs.

[0101] See Figure 1 In one example, in gas supply unit 2, the downstream pipeline of buffer gas container 2-5 in the first supply branch (cold thrust branch) and the downstream pipeline of flow controller 2-6 in the second supply branch (electric thrust branch) are interconnected via a low-pressure isolation valve 2-13. The low-pressure isolation valve 2-13 is electrically connected to the propulsion system drive and control unit 4. During on-orbit operation, the low-pressure isolation valve 2-13 is normally closed, and the two supply branches operate independently. When either branch loses its gas supply capability due to a failure of components such as a pressure reducer or filter, the propulsion system drive and control unit 4 can issue a command to open the low-pressure isolation valve 2-13. At this time, the normally operating branch can supply working fluid to the thruster of the failed branch through the low-pressure isolation valve 2-13. For example, if the second pressure reducer 2-2 of the electric propulsion branch fails, the low-pressure isolation valve 2-13 can be opened, allowing the working propellant of the first supply branch to flow through the buffer gas container 2-5 and the low-pressure isolation valve 2-13 to the micro-Newton electric thruster 3-2, restoring its basic propulsion capability. Although it may not achieve optimal performance, it provides critical fault redundancy capability, ensuring the satellite's most basic attitude control and orbit maintenance capabilities, and greatly improving the system's mission reliability.

[0102] On the other hand, while the high-pressure isolation valve 1-11 is the primary means of maintaining system centroid stability, the low-pressure isolation valve 2-13 can serve as an auxiliary measure. During long-term operations, if the thruster operating time and working fluid consumption of the two branches differ significantly, it may lead to differences in gas capacity or residual working fluid pressure after the low-pressure lines of the two branches. Under specific operating conditions (such as when neither thruster is operating and the high-pressure isolation valve 1-11 has been balanced), the control unit can briefly open the low-pressure isolation valve 2-13 to bring the working fluid pressure of the low-pressure sections of the two branches closer together, supplementing the high-pressure cylinder balancing and further optimizing the overall system centroid stability.

[0103] In one example, the propulsion system drive and control unit 4 includes a first propulsion circuit box 4-1 and a second propulsion circuit box 4-2. The automatic control equipment for the cold propulsion branch is electrically connected to the first propulsion circuit box 4-1, and the automatic control equipment for the electric propulsion branch is electrically connected to the second propulsion circuit box 4-2. A high-pressure isolation valve 1-11 and a low-pressure isolation valve 2-13 are simultaneously electrically connected to both the first propulsion circuit box 4-1 and the second propulsion circuit box 4-2.

[0104] In this embodiment, the micronewton-level hybrid propulsion system consists of a cold-push branch and an electric-push branch. The cold-push branch and the electric-push branch are connected by a high-pressure isolation valve. In some examples, in addition to the connection via the high-pressure isolation valve, a low-pressure isolation valve is also connected downstream. The connections between the components in the cold-push branch and the electric-push branch, the connection between the high-pressure isolation valve and the two branches, and the connection between the low-pressure isolation valve and the two branches are all achieved through pipelines. The pipelines are connected by welding or by a metal ball head-metal conical surface screw hard seal method.

[0105] This embodiment also provides a micro-Newton-level hybrid propulsion method based on any of the micro-Newton-level hybrid propulsion systems in the above embodiments. The method is executed by the propulsion system drive and control unit 4 and includes the following steps:

[0106] S1: Receive thrust commands from the spacecraft platform.

[0107] S2: Based on the preset thrust distribution strategy based on the thrust critical point, selectively control the micro-Newton level cold gas thruster 3-1 and the micro-Newton level electric thruster 3-2 to work individually or in combination to output the target thrust.

[0108] S3: Monitor the pressure inside the first high-pressure gas cylinder 1-1 and the second high-pressure gas cylinder 1-2, which are arranged symmetrically.

[0109] S4: When the pressure difference between each high-pressure gas cylinder reaches the preset threshold, control the opening of high-pressure isolation valve 1-11 to balance the working fluid.

[0110] This method combines innovative hardware with intelligent control to achieve optimal efficiency and autonomous center of mass stability across the entire thrust range, enabling a single system to flexibly meet various mission requirements.

[0111] In one example, the thrust allocation strategy is based on thrust thresholds including:

[0112] Minimum thrust critical point T min (For example, 0.1 μN), which corresponds to the minimum stable output thrust of a micro-Newton level cold gas thruster;

[0113] The first thrust critical point T1 (e.g., 5 μN) corresponds to the minimum stable output thrust of the micro-Newton electric thruster.

[0114] The second thrust critical point T2 (e.g., 50 μN) corresponds to the maximum stable output thrust of the micro-Newton electric thruster.

[0115] Maximum thrust critical point T max (e.g., 1000 μN), corresponding to the maximum stable output thrust of a micro-Newton-level cold gas thruster.

[0116] By defining a clear thrust critical point, precise decision-making basis is provided for intelligent thrust allocation, ensuring the clarity and reliability of the control logic.

[0117] In one example, the specific operating modes (thrust allocation strategy based on thrust critical point) for selectively controlling the individual or coordinated operation of the micro-Newton cold gas thruster and the micro-Newton electric thruster are as follows:

[0118] Operating Mode 1 (Command Thrust F < T1): Controls the operation of the micro-Newton level cold gas thruster 3-1. This mode utilizes the ultra-high precision and stability of cold gas thrust at the sub-micro-Newton level.

[0119] Operating Mode 2 (T1 ≤ F ≤ T2): This generally corresponds to the drag-free control micro-thrust mode, where the average thrust is relatively large and the control accuracy requirement is high. Therefore, in this mode, the air-cooled unit and the electric thruster work together. For example, the micro-Newton electric thruster 3-2 outputs the average thrust required for the periodic drag-free control process, while the micro-Newton air-cooled unit 3-1 outputs the variable thrust (fluctuating thrust) relative to the average thrust, so as to ensure sufficient thrust while further improving the control accuracy of the thrust.

[0120] Working Mode 3 (F > T2): This mode can be further divided into two cases, one of which is T2 ≤ F ≤ T. max At this time, the micro-Newton level cold air thruster 3-1 is controlled to work or the cold air and electric thrusters are controlled to work simultaneously; another option is F > T2 or the cold air and electric thrusters are controlled to work simultaneously. For example, when a larger thrust is required, the cold air and electric thrusters output thrust simultaneously, and the combined thrust of the two provides a larger thrust output.

[0121] The aforementioned operating modes ensure the use of high-precision cold gas thrust at sub-micronewton levels, high-specific-impulse electric thrust at micronewton levels, and flexible allocation when high thrust is required, thereby achieving optimal overall efficiency across the entire range. A propulsion system employing this invention can flexibly adapt to various mission requirements, from extremely high-precision drag-free control to conventional attitude and orbit control, with overall performance far exceeding that of a single-mode propulsion system.

[0122] Any aspects of this invention not described in detail are common knowledge or prior art in the field.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution, and in the absence of conflict between solutions, the various technical features mentioned in each embodiment can be combined in any way to form other implementation methods that can be understood by those skilled in the art.

[0124] Furthermore, without departing from the scope of the present invention, modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, shall not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A micro-Newton level hybrid propulsion system based on a gaseous working fluid, characterized in that, include: A gas storage unit for storing a high-pressure gas working medium includes at least one first high-pressure gas cylinder and at least one second high-pressure gas cylinder arranged symmetrically, and a high-pressure isolation valve connected between the first high-pressure gas cylinder and the second high-pressure gas cylinder. A gas supply unit, connected to the gas storage unit, is used to reduce the pressure and regulate the flow of the high-pressure gas working medium. The gas supply unit includes a first supply branch and a second supply branch arranged in parallel and symmetrically. A first pressure reducer and a second pressure reducer are respectively provided in the first supply branch and the second supply branch. The first pressure reducer and the second pressure reducer are both mechanical pressure reducers. A thruster unit, connected to the gas supply unit, is used to eject a working propellant to generate thrust. The thruster unit includes at least one micro-Newton cold gas thruster connected to the first supply branch and at least one micro-Newton electric thruster connected to the second supply branch. The propulsion system drive and control unit is electrically connected to the gas storage unit, gas supply unit and thruster unit; The propulsion system drive and control unit is configured as follows: Receive thrust commands and, according to a preset thrust distribution strategy based on thrust critical points, selectively control the micro-Newton cold gas thruster and the micro-Newton electric thruster to work individually or in combination. The pressure inside the first high-pressure gas cylinder and the second high-pressure gas cylinder is monitored. When the pressure difference between the two reaches a preset threshold, the high-pressure isolation valve is opened to balance the working fluid.

2. The micro-Newton level hybrid propulsion system according to claim 1, characterized in that: A buffer gas container is also provided downstream of the first pressure reducer in the first supply branch; A flow controller is also provided downstream of the second pressure reducer in the second supply branch.

3. The micro-Newton level hybrid propulsion system according to claim 2, characterized in that: A first high-pressure throttling orifice and a second high-pressure throttling orifice are respectively provided in the upstream pipelines of the first pressure reducer and the second pressure reducer.

4. The micro-Newton level hybrid propulsion system according to claim 2, characterized in that: The downstream of the buffer gas container in the first supply branch and the downstream of the flow controller in the second supply branch are connected via a low-pressure isolation valve, which is electrically connected to the propulsion system drive and control unit.

5. The micro-Newton level hybrid propulsion system according to claim 3, characterized in that: A first low-pressure throttling orifice and a second low-pressure throttling orifice are respectively provided in the inlet pipes of the micro-Newton-level cold gas thruster and the micro-Newton-level electric thruster.

6. The micro-Newton level hybrid propulsion system according to claim 5, characterized in that: The first high-pressure throttling orifice and the second high-pressure throttling orifice have the same diameter, and their diameters are... Satisfy the following formula: in, The flow coefficient of the high-pressure throttling orifice is obtained through experimental calibration; This refers to the rated filling pressure of the high-pressure gas cylinder. This refers to the density of the gaseous working medium at the rated filling pressure and design temperature. The first low-pressure throttling orifice and the second low-pressure throttling orifice have the same diameter, and their diameters are... Satisfy the following formula: in, The flow coefficient of the low-pressure throttling orifice was obtained through experimental calibration. To buffer the outlet pressure of the gas container; This refers to the density of the gaseous working medium at the rated outlet pressure and design temperature of the buffer gas container.

7. The micro-Newton level hybrid propulsion system according to claim 1, characterized in that: The working gas is xenon.

8. A micro-Newton level hybrid propulsion method based on a gaseous working fluid, characterized in that: The method employing the microNewton-level hybrid propulsion system as described in any one of claims 1-7 includes: Receive thrust command; According to the preset thrust distribution strategy based on the thrust critical point, the micro-Newton level cold gas thruster and the micro-Newton level electric thruster are selectively controlled to work alone or in combination to output the target thrust. Monitor the pressure inside the first and second high-pressure gas cylinders, which are symmetrically arranged. When the pressure difference between each high-pressure gas cylinder reaches a preset threshold, the high-pressure isolation valve is opened to balance the working fluid in each high-pressure gas cylinder.

9. The method according to claim 8, characterized in that, The thrust allocation strategy is based on the following thrust critical points: The minimum thrust critical point corresponds to the minimum stable output thrust of the micro-Newton level cold gas thruster. The first thrust critical point corresponds to the minimum stable output thrust of the micro-Newton electric thruster. The second thrust critical point corresponds to the maximum stable output thrust of the micro-Newton electric thruster. The maximum thrust critical point corresponds to the maximum stable output thrust of the micro-Newton level cold gas thruster.

10. The method according to claim 9, characterized in that, Selectively controlling the operation of micro-Newton level cold gas thrusters and micro-Newton level electric thrusters, either individually or in combination, specifically includes: When the commanded thrust is less than the first thrust critical point, the micro-Newton cold gas thruster is controlled to work. When the commanded thrust is between the first thrust critical point and the second thrust critical point, the micro-Newton level cold gas thruster and the micro-Newton level electric thruster are controlled to work together. When the commanded thrust is greater than the second thrust critical point, the micro-Newton level cold gas thruster is controlled to work, or the micro-Newton level cold gas thruster and the micro-Newton level electric thruster are controlled to work in coordination.

Images