Wide-range high-precision piezoelectric cold air variable thrust module and multi-mode cooperative control method

Abstract

The invention relates to the technical field of spacecrafts, in particular to a wide-range high-precision piezoelectric cold air variable thrust module and a multi-mode cooperative control method. The piezoelectric cold air variable thrust module comprises a piezoelectric proportional valve, a nozzle throat throttling unit, a sensor set, a shell assembly and a module controller. The module controller is configured to selectively control the piezoelectric proportional valve in an open-loop working mode, a flow closed-loop working mode, a displacement closed-loop working mode or a displacement flow double-closed-loop working mode according to the thrust instruction and the sensor signal. Through multi-mode selective control of the module controller, the module can realize high-precision and quick-response thrust output in a thrust range of 10 <-2 > mu N to 103 mu N. The invention further provides a corresponding multi-mode cooperative control method, and high-performance output of the module within the full thrust range is achieved through adaptive control of the working mode and the thrust range. The technical problem that wide thrust range, high precision and quick response cannot be realized at the same time in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of spacecraft, and particularly relates to a wide-range high-precision piezoelectric cold-gas variable thrust module and a multi-mode cooperative control method. BACKGROUND

[0002] Micro-newton cold-gas variable thrust module is a key execution component for performing space gravitational wave detection, high-precision earth gravity field mapping and other advanced space science tasks. With the improvement of task requirements, the performance of the thrust module is required to cover a wide thrust range (such as 10-2 muN to 10³ muN), have high thrust resolution (such as 0.1 muN), fast response (such as response time < 50 ms in some thrust range) and stable work in complex space environment (wide temperature range, strong electromagnetic interference).

[0003] The existing micro-newton cold-gas thrust technology can only meet the requirements on the above individual indicators, but it is difficult to simultaneously consider all high-performance indicators. For example, the thrust range of some technical solutions is narrow; the resolution of some solutions is insufficient or the response is slow in the low thrust segment; and some solutions have poor environmental adaptability and unstable on-orbit performance. Such technical limitations seriously restrict the development of high-precision space missions. SUMMARY

[0004] The purpose of the present application is to provide a wide-range high-precision piezoelectric cold-gas variable thrust module and a multi-mode cooperative control method for the piezoelectric cold-gas variable thrust module, so as to solve the main technical problem that the prior art cannot simultaneously realize wide thrust range, high precision and fast response.

[0005] In order to achieve the above-mentioned purpose, in a first aspect, the present application provides a wide-range high-precision piezoelectric cold-gas variable thrust module, comprising: A piezoelectric proportional valve, comprising an inlet joint, a bellows, an armature assembly and a piezoelectric driving assembly, the bellows is used to realize the elastic connection of the inlet joint and the armature assembly, the piezoelectric driving assembly is used to provide a driving force for driving the armature assembly to move along the axial direction, and the armature assembly is matched with a valve port through axial movement to control the opening degree of the flow passage; A nozzle throat throttling unit, which is a micro-newton Laval nozzle, is matched with a valve needle of the armature assembly, and is used to adjust the thrust by changing the throat throttling area; A sensor group, comprising a temperature sensor for collecting the temperature of each point of the module, a flow sensor for providing a module flow signal, and a valve core position sensor for providing a valve core position signal; An outer shell assembly, which encapsulates the piezoelectric proportional valve, the nozzle throat throttling unit and the sensor group in its interior; The module controller is electrically connected with the sensor group and the piezoelectric proportional valve, and is configured to be capable of selectively controlling the piezoelectric proportional valve in an open loop working mode, a flow closed loop working mode, a displacement closed loop working mode or a displacement-flow double closed loop working mode according to the thrust command and the sensor signal, so that the module is capable of realizing high-precision and fast-response thrust output in a thrust range of 10 -2 μN to 10 3 μN.

[0006] Optionally, the piezoelectric driving assembly comprises at least one group of piezoelectric ceramics, each group of piezoelectric ceramics comprising two piezoelectric ceramic sheets configured to elongate in opposite directions under a driving voltage to jointly push or pull the driver frame.

[0007] Optionally, the armature assembly comprises a leaf spring arranged to center the armature assembly and provide a sealing force, so that the valve needle stably moves in the flow passage hole of the sealing module and realizes sealing.

[0008] Optionally, the armature assembly further comprises an armature and a valve needle arranged at the front end of the armature, the armature is provided with an airflow passage, and a plurality of air holes are arranged on the front end of the airflow passage in the circumferential direction. The piezoelectric cold gas variable thrust module further comprises a support assembly fixedly connected with the shell of the piezoelectric proportional valve, the support assembly comprises an upper support block and a lower support block, the upper support block is provided with an upper through hole through which the armature passes and abuts against the armature, the lower support block is provided with a lower through hole with a diameter larger than the outer diameter of the armature, so that there is a gap between the armature passing through the lower support block and the lower through hole, forming an airflow buffer cavity, the leaf spring is arranged between the upper support block and the lower support block, the armature passes through the upper through hole and the lower through hole, the valve needle is inserted into the flow passage hole of the sealing module, and the air holes are in communication with the airflow buffer cavity and the flow passage hole of the sealing module.

[0009] Optionally, the support assembly is connected with the shell of the piezoelectric proportional valve through a base, the base comprises a hollow cylinder and an annular stopper arranged at the lower end of the hollow cylinder, the outer periphery of the hollow cylinder is attached to the inner wall of the shell of the piezoelectric proportional valve, and the annular stopper is located outside the shell of the piezoelectric proportional valve and abuts against the lower end of the shell of the piezoelectric proportional valve. The support assembly is fixedly arranged in the hollow cylinder, the sealing module and the nozzle throat throttling unit are arranged in the hollow cylinder, the sealing module is located between the support assembly and the nozzle throat throttling unit, the sealing module comprises a sealing block and a sealing pressing block, the sealing block presses against the nozzle throat throttling unit, the sealing pressing block is located between the support assembly and the sealing block, the sealing pressing block is provided with a valve needle through hole, the valve needle through hole is in communication with the airflow buffer cavity, and the valve needle is inserted into the flow passage hole of the sealing block after passing through the sealing block.

[0010] Optionally, the valve core position sensor works based on the principle of capacitance change or Wheatstone bridge, and its sensing head is fixed on the bellows or armature assembly to follow the movement of the armature assembly.

[0011] Optionally, the flow sensor comprises a flow channel and a MEMS chip, and non-metallic support plates are installed on both sides of the flow channel, which are in contact with the housing assembly to enhance the anti-impact and anti-vibration performance.

[0012] Optionally, the housing assembly comprises a cylindrical housing, an upper cover and a bottom cover, the cylindrical housing is an integrally formed titanium alloy housing, and the upper cover and the bottom cover are connected with the cylindrical housing to form a sealed space.

[0013] Optionally, the internal cables of the piezoelectric cold gas variable thrust module are processed by the process of double-twisted and shielded, and all electrical signals are uniformly output through not more than two electrical connectors.

[0014] Optionally, the module controller is an external propulsion system line box.

[0015] Optionally, the open-loop working mode is configured as follows: the module controller receives the thrust instruction, directly calculates the corresponding driving voltage based on the preset thrust-driving voltage mapping relationship, and outputs it to the piezoelectric proportional valve; The flow closed-loop working mode is configured as follows: the module controller receives the thrust instruction and converts it into a target flow value, then takes the flow signal fed back by the flow sensor in real time as the control target, adjusts the driving voltage output to the piezoelectric proportional valve through the flow closed-loop control algorithm, so that the actual flow converges to the target flow value; The displacement closed-loop working mode is configured as follows: the module controller receives the thrust instruction and converts it into a target valve core displacement value, then takes the valve core position signal fed back by the valve core position sensor in real time as the control target, adjusts the driving voltage output to the piezoelectric proportional valve through the displacement closed-loop control algorithm, so that the actual displacement of the valve core converges to the target valve core displacement value; The displacement-flow double closed-loop working mode is configured as follows: the module controller first performs displacement coarse closed-loop control based on the feedback signal of the valve core position sensor, and then performs flow precise closed-loop control based on the feedback signal of the flow sensor.

[0016] In a second aspect, the present application also provides a multi-mode cooperative control method for a piezoelectric cold gas variable thrust module, The module comprises a piezoelectric proportional valve, a flow sensor, a valve core position sensor and a module controller, and the method comprises the following steps: The thrust instruction receiving step: the module controller receives the thrust instruction from the upper computer; The working mode decision and execution step: according to the size of the thrust instruction and / or the demand for the dynamic performance of the thrust change, the corresponding control working mode is selected and executed to drive the piezoelectric proportional valve, wherein: When rapid and coarse thrust adjustment is required, an open-loop operating mode is adopted: the module controller directly outputs the drive voltage based on the preset thrust-drive voltage mapping relationship; When the thrust value corresponding to the thrust command is less than 10 2 When the thrust resolution is required to be ≤0.1 μN and the response time is <50ms, the displacement closed-loop working mode or the displacement-flow dual closed-loop working mode shall be adopted. The displacement closed-loop working mode uses the feedback signal of the valve core position sensor as the target for precise control. The displacement-flow dual closed-loop working mode first uses the feedback signal of the valve core position sensor to perform rapid displacement coarse closed loop, and then uses the feedback signal of the flow sensor to perform precise flow closed loop. When the thrust value corresponding to the thrust command is 10 -2 μN to 10 3 Within the μN range, and with a thrust resolution ≤1 μN and a response time <250 ms required, a flow closed-loop operating mode or a displacement-flow dual closed-loop operating mode is adopted; the flow closed-loop operating mode uses the feedback signal from the flow sensor as the target for stable control. Through adaptive control of operating modes and thrust range, the module can achieve 10 -2 μN to 10 3 Within a thrust range of μN, achieve a thrust of less than 10. 2 At a resolution ≤ 0.1 μN and a response time < 50 ms, the thrust is 10. 2 μN to 10 3 Performance output with resolution ≤1 μN and response time <250 ms at μN.

[0017] The above-described technical solution of the present invention has the following advantages: The piezoelectric cold gas variable thrust module provided by this invention successfully achieves multi-level (10) thrust across five orders of magnitude (10) on a single module by integrating a piezoelectric proportional valve, a nozzle throat throttling unit, a multi-sensor group, and a module controller supporting multi-mode selection into a single housing assembly. -2 μN to 10 3 With its wide thrust range coverage (μN), high-precision thrust output at the micronewton level, and rapid response capability at the millisecond level, it fundamentally solves the inherent technical contradiction in existing technologies where it is difficult to achieve both wide range, high precision, and fast response.

[0018] The multi-mode cooperative control method for piezoelectric-cooled gas-varying thrust modules provided by this invention establishes an intelligent decision-making mechanism that automatically selects and executes the optimal control mode based on the thrust command magnitude. This enables the piezoelectric-cooled gas-varying thrust module to dynamically adapt to the performance requirements of different thrust ranges, thereby systematically ensuring its performance across the entire thrust range (10). -2 μN to 10 3The high resolution and fast response performance indicators can be stably achieved in the range of 0- 10 μN, and the control strategy can be switched from the fixed mode to the adaptive optimization. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings of the present application are provided for illustration only, and the proportions and quantities of the components in the drawings may not be consistent with the actual products.

[0020] Figure 1 is a cross-sectional schematic view of a piezoelectric cold gas variable thrust module in an embodiment of the present application; Figure 2 is a schematic view of a piezoelectric proportional valve in an embodiment of the present application; Figure 3 is a cross-sectional schematic view of a piezoelectric proportional valve in an embodiment of the present application; Figure 4 is a cross-sectional schematic view of a piezoelectric proportional valve in an embodiment of the present application; Figure 3 is a cross-sectional schematic view of a piezoelectric proportional valve in an embodiment of the present application; Figure 5 is a cross-sectional schematic view of a flow sensor in an embodiment of the present application; Figure 6 is an enlarged schematic view of a nozzle throat throttling unit in an embodiment of the present application; Figure 7 is a control logic schematic view of a piezoelectric cold gas variable thrust module in an embodiment of the present application.

[0021] In the drawings: 100: piezoelectric proportional valve; 110: inlet joint; 120: corrugated pipe; 130: armature assembly; 131: armature; 1311: air hole; 132: valve needle; 133: sheet spring; 140: piezoelectric drive assembly; 141: driver frame; 142: piezoelectric ceramic sheet; 143: gland; 144: disc spring; 150: housing of the piezoelectric proportional valve; 160: support assembly; 161: upper support block; 162: lower support block; 163: air flow buffer cavity; 170: base; 180: sealing module; 181: sealing pressing block; 182: sealing block 200: nozzle throat throttling unit 300: temperature sensor 400: flow sensor 401: flow channel 402: circuit board of flow sensor 403: non-metallic support plate 404: metal ring 500: valve core position sensor 501: circuit board of valve core position sensor 502: sensing head of valve core position sensor 600: housing assembly 601: cylindrical housing 602: upper cover 603: bottom cover 700: module inlet 800: electrical connector 900: cable DETAILED DESCRIPTION

[0022] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0023] As shown in Figures 1 to 7 , the present embodiment provides a wide-range high-precision piezoelectric cold-gas variable thrust module. The core is to solve the technical problem that wide range, high precision and fast response are difficult to be considered in the field of micro-newton thrust by combining unique mechanical structure design and intelligent multi-mode control strategy.

[0024] The variable thrust module mainly includes a piezoelectric proportional valve 100, a nozzle throat throttling unit 200, a sensor group, a housing assembly 600 and a module controller.

[0025] The piezoelectric proportional valve 100 is an actuator of the module. Referring to Figure 2 and Figure 3, which includes an inlet joint 110, a bellows 120, an armature assembly 130, and a piezoelectric drive assembly 140. One end of the bellows 120 is welded to the inlet joint 110, and the other end is welded to the armature assembly 130, achieving dynamic isolation and sealing of the high-pressure gas passage from the piezoelectric driver, while providing flexible space for the axial movement of the armature assembly 130. The piezoelectric drive assembly 140 is used to provide precise driving force to drive the armature assembly 130 to move axially. The armature assembly 130 moves axially, so that the valve needle 132 at its front end cooperates with the valve port, thereby precisely controlling the opening of the gas flow passage.

[0026] Referring to Figure 1 and Figure 6 , the nozzle throat throttling unit 200 is a micro-newton-level Laval nozzle, which precisely cooperates with the tip of the valve needle 132 of the armature assembly 130. By the axial displacement of the valve needle 132, the effective throttling area of the nozzle throat can be continuously and accurately changed, thereby realizing linear regulation of the thrust.

[0027] Referring to Figure 1 and Figure 3 , the sensor group is used to provide real-time feedback for closed-loop control. It includes: Temperature sensor 300: distributed at key nodes such as the module inlet 700, the flow sensor 400 flow passage inlet and outlet, the piezoelectric proportional valve 100 inlet and outlet, etc., used to collect temperature signals in a wide temperature range for performance compensation by the controller. In this embodiment, the temperature sensor 300 uses a thermistor.

[0028] Flow sensor 400: used to provide real-time mass flow signals of the module.

[0029] Valve core position sensor 500: used to provide real-time displacement signals of the armature assembly 130.

[0030] Referring to Figure 1 , the housing assembly 600 serves as the packaging and protection structure of the module, which encapsulates all core components such as the piezoelectric proportional valve 100, the nozzle throat throttling unit 200, and the sensor group inside it, forming a whole.

[0031] The module controller (not shown in the figure, in this embodiment the module controller is an external propulsion system line box) is electrically connected to the sensor group and the piezoelectric proportional valve 100 through the electrical connector 800. The controller is programmed to realize multiple working modes, and can intelligently select open-loop, flow closed-loop, displacement closed-loop, or displacement and flow double closed-loop working modes to control the piezoelectric proportional valve 100 according to the thrust command and sensor signals.

[0032] The working principle of the module in this embodiment is as follows: after the host computer receives the thrust command, the module controller collects the flow sensor signal, the flow sensor temperature signal, the valve core position sensor displacement signal, the piezoelectric proportional thrust generator inlet and outlet temperature signal and the like, cooperates with the preset different working modes, drives the piezoelectric proportional thrust generator to work, so that the module flow converges to the thrust calibration value, thereby obtaining the required thrust. When a larger thrust is required, the driving voltage becomes larger, and the opening of the proportional thrust generator becomes larger, thereby making the thrust larger. When a smaller thrust is required, the driving voltage becomes smaller, and the opening of the proportional thrust generator becomes smaller, thereby making the thrust smaller.

[0033] Through the multi-mode selective control of the above-mentioned module controller, the variable thrust module of the embodiment is configured to be able to work in a wide range of five orders of magnitude of thrust from 10 -2 μN to 10 3 μN, and to realize high-precision and fast-response thrust output.

[0034] In an example, the piezoelectric driving assembly 140 is further optimized, as shown in Figure 2 and Figure 3 , the piezoelectric driving assembly 140 includes at least one set of piezoelectric ceramics. The number of piezoelectric ceramics is determined according to the actual force requirement, which is generally even, two piezoelectric ceramic sheets 142 form a set, and the two piezoelectric ceramic sheets 142 are configured to elongate in opposite directions under the driving voltage to jointly push or pull the driver frame 141. This "push-pull" working mode enables them to jointly push or pull the driver frame 141, thereby outputting greater driving force and more stable displacement, effectively overcoming the shortcomings of traditional single piezoelectric sheet driving force, and providing a power basis for wide-range thrust output.

[0035] In an example, the armature assembly 130 is refined. As shown in Figure 3 and Figure 4 , the armature assembly 130 includes a sheet spring 133. The sheet spring 133 is arranged to center the armature assembly 130 and provide an initial sealing force. The periphery is fixed, and the center part is connected with the armature 131, and through the elastic deformation thereof, on the one hand, the armature 131 is constrained to move accurately in a straight line along the axial direction, preventing radial shaking; on the other hand, the pre-pressing force thereof enables the valve needle 132 to stably press in the flow passage hole of the sealing module 180 at zero position, realizing reliable normally closed sealing.

[0036] In an example, the gland 143 is screwed to the tail of the armature assembly 130 and is pressed against the piezoelectric drive assembly 140 by the force exerted by the disc spring 144. As a part of the direct connection between the armature assembly 130 and the piezoelectric drive assembly 140, the gland 143 fixes and adjusts the height of the armature assembly 130 to achieve the opening and closing of the valve port. The disc spring 144 is pre-compressed between the housing 150 of the piezoelectric proportional valve and the gland 143 to provide and maintain a constant axial mechanical pre-tightening force. This pre-tightening force effectively eliminates the gap in the transmission chain, ensuring the non-hysteresis and continuous transmission of the bidirectional displacement of the piezoelectric drive, while protecting the piezoelectric ceramic 142 from tensile stress impact and compensating for the deformation of the parts in a wide temperature range environment to maintain the stability and reliability of the thrust control.

[0037] In an example, referring to Figure 4 , the armature assembly 130 further includes an armature 131 and a valve needle 132 arranged at the front end of the armature 131. The armature 131 is internally provided with an axial air flow passage, and a plurality of radial air holes 1311 are arranged circumferentially at the front end of the passage.

[0038] The module further includes a support assembly 160 fixedly connected to the housing 150 of the piezoelectric proportional valve. The support assembly 160 includes an upper support block 161 and a lower support block 162. The upper support block 161 is provided with an upper through hole through which the armature 131 passes and which is fitted to the outer wall of the armature 131, serving as an auxiliary guide. The lower support block 162 is provided with a lower through hole having a diameter greater than the outer diameter of the armature 131, such that the armature 131 passing through the lower through hole has an annular gap with the lower through hole, forming an air flow buffer chamber 163. The leaf spring 133 is compressed between the upper support block 161 and the lower support block 162. The armature 131 passes through the upper through hole and the lower through hole in sequence, and the valve needle 132 is inserted into the flow channel hole of the sealing module 180. High-pressure gas flows in from the inlet, is sprayed out from the circumferential air holes 1311 at the front end of the air flow passage in the armature 131, enters the air flow buffer chamber 163 for pressure stabilization, and then enters the flow channel hole of the sealing module 180. This design can make the air flow more stable and uniform before throttling, which helps to improve the stability of the thrust.

[0039] In an example, referring to Figure 3 and Figure 4 , the support assembly 160 is connected to the housing 150 of the piezoelectric proportional valve through a dedicated base 170. The base 170 is a hollow cylinder, and the lower end of the base 170 is provided with an annular stopper extending outward. The outer periphery of the hollow cylinder is tightly fitted to the inner wall of the housing 150 of the piezoelectric proportional valve, and the annular stopper is located outside the housing 150 and abuts against the lower end of the housing, achieving axial positioning.

[0040] The support assembly 160 is fixedly arranged in the hollow cylinder of the base 170. The sealing module 180 and the nozzle throat throttling unit 200 are also sequentially arranged in the hollow cylinder of the base 170. The sealing module 180 is located between the support assembly 160 and the nozzle throat throttling unit 200, and includes a sealing pressing block 181 and a sealing block 182. The sealing block 182 is pressed on the nozzle throat throttling unit 200, and the sealing pressing block 181 is located between the support assembly 160 and the sealing block 182. The sealing pressing block 181 is provided with a valve needle through hole, which is in communication with the airflow buffer cavity 163. The valve needle 132 is sequentially inserted into the flow channel hole of the sealing block 182 after passing through the through hole of the sealing pressing block 181 and the sealing block 182. The integrated design ensures the coaxiality and air tightness between the components, and is a structural guarantee for high-precision control.

[0041] Based on any of the above examples, referring to Figure 3 , the valve core position sensor 500 works based on the principle of capacitance change or Wheatstone bridge. The sensing head 502 of the valve core position sensor 500 is fixed on the corrugated pipe 120 or the armature assembly 130 to follow the movement of the armature assembly; and the circuit board 501 of the valve core position sensor 500 is fixed on the valve housing, so as to accurately measure the micro displacement of the valve core in a non-contact manner.

[0042] In an example, as shown in Figure 5 , the flow sensor 400 includes a flow channel 401 and a MEMS chip (integrated on a circuit board 402). Non-metallic support plates 403 are installed on both sides of the flow channel 401, and the non-metallic support plates 403 are in contact with the inner wall of the housing assembly 600 and are fixed by metal rings 404, so as to greatly enhance the impact resistance and shock resistance of the flow channel and the whole sensor. The hardness of the non-metallic support plate 403 is less than that of the metal, so that it has the impact resistance and shock resistance. In an example, in order to improve the impact resistance and shock resistance while improving the firmness of the installation connection, the non-metallic support plate 403 is provided with a groove on the outer periphery, and the metal ring 404 is arranged in the groove, so as to facilitate the screw connection and fixation, and greatly enhance the impact resistance and shock resistance of the flow channel and the whole sensor.

[0043] Referring to Figure 1In an example, the shell assembly 600 includes a cylindrical shell 601, an upper cover 602, and a bottom cover 603. The cylindrical shell 601 is preferably a one-piece titanium alloy shell, and the upper cover 602 and the bottom cover 603 are connected to the cylindrical shell 601 by welding or screws to form a high-strength sealed space and provide excellent electromagnetic shielding capability. The internal cables 900 of the module are all processed by a twisted and shielded process, and all electrical signals are uniformly output through no more than two electrical connectors 800 on the upper cover 602. All components and circuits are encapsulated in the cylindrical armor, and electrical signals are uniformly output by two electrical connectors. Shielding and twisted process is used between all possible interference circuits, which has the ability to resist strong electromagnetic interference in orbit and greatly reduces the introduction points of electromagnetic interference. The module controller is preferably an external propulsion system circuit box, which is connected to the module through the electrical connector 800 for easy upgrading and maintenance.

[0044] The module inlet 700 is connected to the flow sensor 400 at one end and extends out of the upper cover 602 at the other end for connection of the module to other components.

[0045] The four working modes of the module controller are configured in this embodiment. The module controller is programmed to perform at least one of the following working modes: Open-loop working mode: the controller receives a thrust command, directly calculates a corresponding drive voltage U based on a preset thrust-drive voltage mapping relationship (obtained through ground calibration), and outputs the drive voltage U to the piezoelectric proportional valve 100. This mode does not rely on real-time feedback of the sensor, has the most rapid response, and is used for fast and rough thrust adjustment.

[0046] Referring to Figure 7 , flow closed-loop working mode: the controller receives a thrust command F com and converts it into a target flow signal value G com Then, the flow signal G m fed back by the flow sensor 400 in real time is taken as a control target, and a drive voltage U is dynamically adjusted by a flow closed-loop control algorithm such as PID to make the actual flow signal G m converge to the target flow signal value G com , thereby ensuring thrust accuracy.

[0047] Referring to Figure 7 , displacement closed-loop working mode: the controller receives a thrust command F com and converts it into a target spool displacement value, and then a spool position signal G nFor control target, the driving voltage U is adjusted by displacement closed-loop control algorithm, so that the actual displacement x of the valve needle 132 generates a spool position signal G n Converge to target displacement value. This mode has fast response speed and is suitable for high dynamic scenarios.

[0048] Referring to Figure 7 , displacement-flow dual closed-loop working mode: the controller receives the thrust command F com , first uses the feedback signal of the spool position sensor 500 G n Fast coarse closed-loop control of displacement ensures millisecond-level response speed; then uses the flow signal fed back by the flow sensor 400 G m For the final control target, accurate closed-loop control of flow is performed to output actual flow And actual thrust , ensuring 0.1 μN-level output accuracy. This mode is the optimal mode that balances response speed and control accuracy.

[0049] The embodiment provides a multi-mode cooperative control method for any piezoelectric cold-gas variable-thrust module. Referring to the control block diagram shown in Figure 7 , the method comprises the following steps: Receiving a thrust command step: the module controller receives a thrust command from an upper computer F com .

[0050] Working mode decision and execution step: the module controller automatically selects and executes the corresponding control working mode according to the size of the thrust command F com , to drive the piezoelectric proportional valve 100. The decision logic is as follows: When fast and rough thrust adjustment is required (such as rapid attitude stabilization after large-range maneuver), the open-loop working mode is adopted.

[0051] When the corresponding thrust value of the thrust command F com is less than 10 2 μN, and the thrust resolution is required to be ≤0.1 μN and the response time is <50 ms (such as ultra-fine adjustment not required for drag control), the displacement closed-loop working mode or the displacement-flow dual closed-loop working mode is adopted. The former uses the feedback signal of the spool position sensor G n as the target for fast and accurate control; the latter first uses G n the signal for fast displacement coarse closed-loop control, and then uses the feedback signal of the flow sensor G mTo achieve precise closed-loop traffic management.

[0052] When thrust command F com The corresponding thrust value is 10 2 μN to 10 3 When the thrust resolution is required to be ≤1 μN and the response time <250 ms (such as during routine attitude adjustment), either the flow closed-loop operating mode or the displacement-flow dual closed-loop operating mode should be used. The former uses the feedback signal from the flow sensor. G m To achieve stable control for the target.

[0053] Through the above-mentioned adaptability control of working modes and thrust range, the module can achieve a thrust range of 10 -2 μN to 10 3 Within a thrust range of μN, a thrust of less than 10 is stably achieved. 2 At a resolution ≤ 0.1 μN and a response time < 50 ms, the thrust is 10. 2 μN to 10 3 Excellent performance output with resolution ≤1 μN and response time <250 ms at μN.

[0054] In summary, the piezoelectric cold gas variable thrust module of this embodiment, based on the bidirectional output of the piezoelectric actuator and the structural design of the armature assembly valve needle and nozzle throat throttling unit, achieves a wide range of thrust output, covering 10 for the first time. -2 ~10 3 On the order of μN. Based on the design of the piezoelectric proportional valve and the throttling unit in the nozzle throat, closed-loop control is achieved by collecting temperature, flow rate, and valve core position signals. The piezoelectric proportional valve actuator is controlled through a cold-push circuit box, achieving a flow rate of less than μN for the first time. 2 Resolution less than or equal to 0.1 μN in the μN range, 10 2 ~10 3 The resolution is less than or equal to 1 μN within the μN range.

[0055] During module operation, the module controller, through the acquisition of flow and displacement signals, outputs a piezoelectric valve drive voltage to adjust the thrust throat area, thereby achieving thrust regulation. The variable thrust regulation modes include four types: open-loop mode, flow closed-loop mode, displacement closed-loop mode, and flow-displacement dual closed-loop mode. The control logic switches according to different scenarios, achieving a thrust of less than 10 for the first time. 2 Response time less than 50ms in the μN range; 10 2 ~10 3 The response time is less than 250ms within the μN range. By calibrating the inverse piezoelectric effect of the piezoelectric proportional valve and the flow sensor over a wide temperature range, on-orbit wide-temperature-range environmental performance compensation is achieved, ensuring the thrust output range and accuracy.

[0056] The present application is not described in detail, which is the common knowledge in the art or prior art.

[0057] Finally, it should be noted that: the above examples are used to illustrate the technical solutions of the present application, but not limited to them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: not every example contains only one independent technical solution, in the absence of scheme conflict, the various technical features mentioned in each example can be combined in any way, forming other embodiments that can be understood by those skilled in the art.

[0058] In addition, the technical solutions described in the foregoing examples are modified, or some technical features are replaced equivalently without departing from the scope of the present application, and the essence of the corresponding technical solutions does not deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A wide-range high-precision piezoelectric cold-gas variable thrust module, characterized in that, The piezoelectric proportional valve comprises an inlet joint, a bellows, an armature assembly and a piezoelectric driving assembly, the bellows is used to achieve elastic connection between the inlet joint and the armature assembly, the piezoelectric driving assembly is used to provide driving force for driving the armature assembly to move axially, the armature assembly cooperates with a valve port through axial movement to control the opening degree of a flow passage; A nozzle throat throttling unit which is a micro-newton-level Laval nozzle cooperates with a valve needle of the armature assembly and is used to adjust the thrust by changing the throat throttling area; A sensor group comprising temperature sensors for collecting the temperature of each point of the module, flow sensors for providing a module flow signal and a valve core position sensor for providing a valve core position signal; A housing assembly encapsulating the piezoelectric proportional valve, the nozzle throat throttling unit and the sensor group inside; The piezoelectric driving assembly comprises at least one group of piezoelectric ceramics, each group of piezoelectric ceramics comprises two piezoelectric ceramic sheets which are configured to elongate in opposite directions under a driving voltage to jointly push or pull the driver frame. a module controller electrically connected with the sensor group and the piezoelectric proportional valve, configured to selectively control the piezoelectric proportional valve in an open loop mode, a flow closed loop mode, a displacement closed loop mode or a displacement-flow dual closed loop mode according to the thrust command and the sensor signals, through multi-mode selective control of the module controller, so that the module can realize high-precision and fast-response thrust output in a thrust range of 10 -2 μN to 10 3 μN.

2. The piezoelectric cold gas variable thrust module of claim 1, wherein: The armature assembly comprises a sheet spring which is arranged to center the armature assembly and provide a sealing force, so that the valve needle moves stably in the flow passage hole of the sealing module and realizes sealing.

3. The piezoelectric cold gas variable thrust module of claim 1, wherein:

4. The piezoelectric cold gas variable thrust module according to claim 3, wherein: The armature assembly further comprises an armature and a valve needle arranged at the front end of the armature, the armature is provided with an airflow passage, and a plurality of air holes are arranged on the front end of the airflow passage in the circumferential direction; The piezoelectric cold gas variable thrust module further comprises a support assembly fixedly connected with the housing of the piezoelectric proportional valve, the support assembly comprises an upper support block and a lower support block, the upper support block is provided with an upper through hole through which the armature fits, the lower support block is provided with a lower through hole with a diameter larger than the outer diameter of the armature, so that there is a gap between the armature passing through the lower support block and the lower through hole, forming an airflow buffer cavity, the sheet spring is arranged between the upper support block and the lower support block, the armature passes through the upper through hole and the lower through hole, the valve needle is inserted into the flow passage hole of the sealing module, and the air holes are in communication with the airflow buffer cavity and the flow passage hole of the sealing module. The support assembly is connected with the housing of the piezoelectric proportional valve through a base, the base comprises a hollow cylinder and an annular stopper arranged at the lower end of the hollow cylinder, the outer periphery of the hollow cylinder is attached to the inner wall of the housing of the piezoelectric proportional valve, and the annular stopper is located outside the housing of the piezoelectric proportional valve and abuts against the lower end of the housing of the piezoelectric proportional valve.

5. The piezoelectric cold gas variable thrust module of claim 4, wherein: ​ The support assembly is fixedly arranged in the hollow cylinder, the sealing module and the nozzle throat throttling unit are arranged in the hollow cylinder, the sealing module is located between the support assembly and the nozzle throat throttling unit, the sealing module comprises a sealing pressing block and a sealing block, the sealing block is pressed on the nozzle throat throttling unit, the sealing pressing block is located between the support assembly and the sealing block, a valve needle through hole is arranged on the sealing pressing block, the valve needle through hole is communicated with the airflow buffer cavity, and the valve needle is inserted into the flow channel hole of the sealing block after penetrating through the sealing block.

6. The piezoelectric cold gas variable thrust module of claim 1, wherein: The valve core position sensor works based on the principle of capacitance change or Wheatstone bridge, and a sensing head thereof is fixed on the bellows or armature assembly to follow the movement of the armature assembly.

7. The piezoelectric cold gas variable thrust module of claim 1, wherein: The flow sensor comprises a flow channel and a MEMS chip, and non-metallic support plates are arranged on two sides of the flow channel, and the non-metallic support plates are in contact with the shell assembly to enhance the impact resistance and vibration resistance.

8. The piezoelectric cold gas variable thrust module according to claim 1, wherein: The shell assembly comprises a cylindrical shell, an upper cover and a bottom cover, the cylindrical shell is an integrally formed titanium alloy shell, and the upper cover and the bottom cover are connected with the cylindrical shell to form a closed space; or The internal cables of the piezoelectric cold gas variable thrust module are processed by a twisted pair and shielding process, and all electrical signals are uniformly output through not more than two electrical connectors; or The module controller is an external propulsion system line box.

9. The piezoelectric cold gas variable thrust module according to claim 1, wherein: The open-loop working mode is configured such that the module controller receives a thrust instruction, directly calculates a corresponding driving voltage based on a preset thrust-driving voltage mapping relationship, and outputs the driving voltage to the piezoelectric proportional valve; The flow closed-loop working mode is configured such that the module controller receives a thrust instruction and converts it into a target flow value, then takes a flow signal fed back by the flow sensor in real time as a control target, adjusts a driving voltage output to the piezoelectric proportional valve through a flow closed-loop control algorithm, so that the actual flow converges to the target flow value; The displacement closed-loop working mode is configured such that the module controller receives a thrust instruction and converts it into a target valve core displacement value, then takes a valve core position signal fed back by the valve core position sensor in real time as a control target, adjusts a driving voltage output to the piezoelectric proportional valve through a displacement closed-loop control algorithm, so that the actual displacement of the valve core converges to the target valve core displacement value; The displacement-flow double closed-loop working mode is configured such that the module controller first performs displacement coarse closed-loop control based on the feedback signal of the valve core position sensor, and then performs flow precise closed-loop control based on the feedback signal of the flow sensor.

10. A multi-mode cooperative control method for piezoelectric cold gas variable thrust module, characterized in that, The module comprises a piezoelectric proportional valve, a flow sensor, a valve core position sensor and a module controller, and the method comprises the following steps: A thrust instruction receiving step: the module controller receives a thrust instruction from an upper computer; The working mode decision and execution step: according to the size of the thrust instruction and / or the demand for thrust change dynamic performance, a corresponding control working mode is selected and executed to drive the piezoelectric proportional valve, wherein: When fast and rough thrust regulation is required, an open-loop working mode is adopted: the module controller directly outputs a driving voltage based on a preset thrust-driving voltage mapping relationship; When the thrust command corresponds to a thrust value less than 10 2 μN, and the required thrust resolution is less than or equal to 0.1 μN and the response time is less than 50 ms, a displacement closed-loop operation mode or a displacement-flow dual closed-loop operation mode is adopted; the displacement closed-loop operation mode is precisely controlled with the feedback signal of the valve core position sensor as the target; the displacement-flow dual closed-loop operation mode first performs a fast displacement coarse closed loop with the feedback signal of the valve core position sensor, and then performs a flow precise closed loop with the feedback signal of the flow sensor. When the thrust command corresponding thrust value is in the range of 10 -2 μN to 10 3 μN, and the thrust resolution is required to be ≤1 μN and the response time is required to be <250 ms, the flow closed loop working mode or the displacement-flow double closed loop working mode is adopted; the flow closed loop working mode is stably controlled with the feedback signal of the flow sensor as the target; By the adaptation control of the working mode to the thrust range, the module achieves a performance output of a resolution ≤ 0.1 μN and a response time < 50 ms at a thrust of less than 10 -2 μN, a resolution ≤ 1 μN and a response time < 250 ms at a thrust of 10 3 μN to 10 2 μN. 2 μN to 10 3 μN.

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