Thrust measuring device and method for pulse plasma thruster

Abstract

The invention discloses a thrust measuring device and method for a pulse plasma thruster, the device comprises a fulcrum shaft, a swing arm, a suspension rope and a counterweight, the counterweight is mounted at one end of the swing arm, the other end of the swing arm is used for mounting the thruster, the swing arm is suspended on the fulcrum shaft through the suspension rope, and the thruster is mounted on the fulcrum shaft through the suspension rope. And the swing arm is in a horizontal state under the action of the counter weight and the thruster. The device has the remarkable technical advantages of being high in precision, free of damping, simple in structure, low in cost and the like, and important technical support is provided for thrust measurement of the pulse plasma thruster.

Description

Technical Field

[0001] This invention relates to the technical field of spacecraft electric propulsion, and in particular to a thrust measurement device and method for pulsed plasma thrusters. Background Technology

[0002] In a pulsed plasma thruster, the propellant is located inside the central anode of a cylindrical discharge channel. An igniter provides initial electrons, which are accelerated in an electric field and collide with the propellant surface, triggering anode-cathode breakdown discharge. The high temperature ablates the propellant surface, causing it to decompose, vaporize, and ionize, thus forming a plasma cluster. Under the action of a radial electric field, the plasma cluster forms a closed loop with the capacitor assembly discharge circuit. The pulsed current induces a circumferential ring magnetic field, and the axial Lorentz force ejects the plasma cluster at high speed, thereby generating a thrust pulse.

[0003] Existing devices for measuring the thrust of pulsed plasma thrusters, such as the Chinese invention patent application CN202510976065.8, disclose a thrust measurement device for a single-component thruster. This invention addresses the problem of insufficient measurement accuracy in existing technologies. The invention includes a reference platform and a measurement mechanism. The measurement mechanism is mounted on the reference platform and includes a thruster adapter frame, a force measuring component, and a fixed frame. The fixed frame is mounted on the reference platform. The force measuring component includes three working sensors, an inner ring, and an outer ring. The three working sensors are evenly distributed and installed in parallel between the inner and outer rings. A spring preload structure is provided between the inner and outer rings. The outer ring is fixed to the fixed frame. One end of the inner ring is connected to the thruster adapter frame, and the other end of the thruster adapter frame has a mounting structure for mounting the thruster. This invention achieves high-precision measurement within the thrust range of 0.5-50N through parallel connection of three sensors and automatic in-situ calibration, significantly improving the accuracy, efficiency, and environmental adaptability of aerospace thruster testing. This invention relates to the field of thrust measurement technology.

[0004] The aforementioned thrust measurement device system is complex, difficult to operate, costly, and easily affected by environmental factors, making it difficult to achieve high-precision measurement, especially under low thrust conditions. Summary of the Invention

[0005] To address the above problems, the present invention provides a thrust measurement device and method for pulsed plasma thrusters that is simple in structure, low in cost, and easy to operate.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention discloses a thrust measuring device for a pulsed plasma thruster, comprising a support shaft, a swing arm, a suspension rope, and a counterweight. The counterweight is installed at one end of the swing arm, and the other end of the swing arm is used to install the thruster. The swing arm is suspended on the support shaft by the suspension rope, and the swing arm is in a horizontal state under the action of the counterweight and the thruster.

[0007] By adopting the above scheme, this application uses a gravity-stabilized suspension method. The swing arm is suspended at the fulcrum by a suspension rope. Utilizing the stability of gravity, the swing arm can be kept in a balanced state without the need for an additional level. Compared with most traditional thrust measurement devices that use damping to quickly reach a steady state, the device in this application utilizes the system's own balance characteristics and can perform measurements without damping. The system structure is simpler and easier to maintain. At the same time, it avoids the interference of damping on the thrust pulse characteristics, thereby improving the measurement accuracy.

[0008] The present invention provides a thrust measuring device for a pulsed plasma thruster, wherein the swing arm is provided with a mounting hole and the support shaft passes through the mounting hole.

[0009] By adopting the above scheme, the support shaft can be deflected relative to the swing arm in the mounting hole, reducing the influence of external factors when the swing arm deflects.

[0010] The present invention provides a thrust measuring device for a pulsed plasma thruster. Further, the upper end of the support shaft is provided with a fixed seat, one end of the suspension rope is connected to the fixed seat, and the other end is connected to the swing arm.

[0011] The present invention provides a thrust measuring device for a pulsed plasma thruster. Further, the swing arm is provided with a Litz wire, which supplies power to the thruster.

[0012] By adopting the above scheme, the electrical interface design is optimized to supply power to the thruster.

[0013] The present invention provides a thrust measuring device for a pulsed plasma thruster, wherein the connection between the suspension rope and the fixed base is a fulcrum, and the Litz wire is connected to the fulcrum.

[0014] By adopting the above scheme, the Litz wire is connected to the fulcrum of the swing arm, minimizing interference with the swing arm's degree of freedom and ensuring the quality of electrical signal transmission.

[0015] A method of using this invention includes the following steps: S1: Before the thruster ignites, record the oscillation process of the swing arm, calculate the interval between the two peak values ​​of the thruster's oscillation displacement, and record it as the system's natural period. ; S2: The thruster ignites to generate thrust, which applies torque to the swing arm, causing the swing arm to deflect. Record the linear displacement d of the swing arm when the thruster deflects. e ; S3: Calculate the thrust T of the thruster:

[0016] J—Moment of inertia of the thruster about the fulcrum; d e —The linear displacement of the swing arm when the thruster generates thrust; L—the distance between the thrust center of the thruster and the fulcrum; —The natural cycle of the system.

[0017] By adopting the above scheme and using the above measuring device in conjunction with the camera's recording function, the thrust of the thruster can be measured without damping, thereby improving the measurement accuracy, simplifying the system structure, and making it easier to maintain.

[0018] In one method of using the present invention, the natural oscillation process of the thruster when it is not ignited and the oscillation process when it is ignited are recorded by a camera. Then, by analyzing the photos, the swing arm swing value is measured using a scale relationship.

[0019] By adopting the above scheme, the natural oscillation process of the thruster and the violent oscillation process after ignition are recorded by camera, and the deflection value of the swing arm is calculated.

[0020] In a further step of the present invention, in step S1, the natural oscillation process of the thruster is recorded before the thruster is ignited, and the violent oscillation process of the thruster is recorded after the thruster is ignited. The linear displacement de of the swing arm is the difference between the equilibrium position of the thruster during violent oscillation and the equilibrium position of the thruster during natural oscillation.

[0021] Compared with the prior art, the present invention has the following beneficial effects: High-precision, undamped measurement: Traditional thrust measurement devices typically use damping to quickly reach a steady state, but damping interferes with the characteristics of the pulse thrust, reducing measurement accuracy. This invention utilizes the system's balance characteristics, allowing measurement without damping, thus improving measurement accuracy, simplifying the system structure, and making it easier to maintain. Gravity-stabilized suspension: By using a suspension rope to suspend the swing arm at the fulcrum, the stability of gravity is utilized, eliminating the need for an additional level, further simplifying the system structure and reducing costs. High resolution, unaffected by environmental factors: Manufactured using 3D printing technology, the system has low stiffness, which improves system resolution and makes it unaffected by environmental factors, resulting in more stable and reliable measurement results. Optimized electrical interface design: Using two Litz wires as electrical interfaces and connecting them to the fulcrum of the swing arm minimizes interference with the swing arm's degrees of freedom, ensuring the quality of electrical signal transmission. The invention will be further described below with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2This is a schematic diagram of the swing arm before and after deflection in this invention; Figure 3 This is a schematic diagram of the swing arm oscillation data processing of the present invention.

[0023] Figure label: 1. Support shaft; 2. Litz line; 3. Swing arm; 4. Suspension rope; 5. Counterweight; 6. Base; 7. Fixing seat; 8. Thrust; 9. Fulcrum. Detailed Implementation

[0024] like Figures 1-3 As shown, this invention discloses a thrust measurement device and method for a pulsed plasma thruster. The device includes a support shaft 1, a swing arm 3, a suspension rope 4, a counterweight 5, and a camera. The lower end of the support shaft 1 has a base 6 for fixing the support shaft 1, and the upper end has a fixing seat 7 for connecting the suspension rope 4. The counterweight 5 is installed at one end of the swing arm 3, and the other end of the swing arm 3 is used to install the thruster 8. The swing arm 3 is suspended from the fixing seat 7 of the support shaft 1 by the suspension rope 4, and the swing arm 3 is in a balanced state under the action of the counterweight 5 and the thruster 8, maintaining a horizontal setting. The suspension rope 4 is preferably a nylon rope with a diameter of 0.14 mm. When measuring the thrust of the thruster 8, the thruster 8 is ignited, and the thrust of the thruster 8 can be calculated by measuring the deflection displacement of the swing arm 3.

[0025] This application adopts a gravity-stabilized suspension method, in which the swing arm 3 is suspended from the fulcrum 9 by a suspension rope 4. Utilizing the stability of gravity, the swing arm 3 can be kept in a balanced state without the need for an additional level. Compared with most traditional thrust measurement devices that use damping to quickly reach a steady state, the device in this application utilizes the system's own balance characteristics and can perform measurements without damping. The system structure is simpler and easier to maintain, and it also avoids the interference of damping on the pulse characteristics of the thruster 8, thereby improving the measurement accuracy.

[0026] A mounting hole is provided through the swing arm 3, through which the support shaft 1 passes and can deflect within the mounting hole, thereby reducing external influences when the swing arm 3 deflects.

[0027] The connection point between the suspension rope 4 and the fixed base 7 is the fulcrum 9. Two Litz wires 2 are laid on the swing arm 3 and connected to the fulcrum 9. The diameter of the Litz wire 2 is about 0.2mm. Through the above settings, the electrical interface design is optimized. Using two Litz wires 2 as electrical interfaces and connecting them to the fulcrum 9 of the swing arm 3 minimizes the interference with the degree of freedom of the swing arm 3 and the impact of temperature drift, ensuring the transmission quality of electrical signals.

[0028] The camera is used to record the position of the swing arm 3, thereby calculating the deflection position of the swing arm 3. The camera also records the position of the thruster 8. Compared with other designs such as using optical displacement sensors, interferometers, or linear voltage displacement sensors, this simplifies the system structure and reduces costs.

[0029] The thrust measurement device of this application is made using 3D printing technology, which is low in cost, has low system stiffness, can improve the system resolution, is not affected by environmental factors, and makes the measurement results more stable and reliable.

[0030] The measurement method includes the following steps: S1: Assemble the thrust measurement device and install the thruster at one end of the swing arm. Under the action of the thruster and the counterweight, bring the swing arm into a balanced state. Activate the camera's recording function and record for three minutes without igniting the thruster, recording the swing arm's oscillation process. Calculate the interval between the two peak oscillation displacements of the thruster, and record it as the system's natural period. .

[0031] S2: The thruster ignites to generate thrust, which applies torque to the swing arm, causing the swing arm to deflect. Record the linear displacement d of the swing arm when the thruster deflects. e The specific process is as follows: A camera records six minutes after the thruster ignition. Then, by analyzing the photographs and using a scale, the swing arm's sway value is measured. The linear displacement *de* of the swing arm is the difference between the equilibrium position during violent thruster oscillation and the equilibrium position during natural thruster oscillation. The thruster's motion direction is opposite to the thrust direction, achieving active vibration reduction and interference suppression.

[0032] S3: Calculate the thrust T of the thruster: ; J—Moment of inertia of the thruster about the fulcrum; d e —The linear displacement of the swing arm when the thruster generates thrust; L—the distance between the thrust center of the thruster and the fulcrum; —The natural cycle of the system.

[0033] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A thrust measuring device for a pulsed plasma thruster, characterized in that, It includes a support shaft (1), a swing arm (3), a suspension rope (4), and a counterweight (5). The counterweight (5) is installed at one end of the swing arm (3), and the other end of the swing arm (3) is used to install a thruster (8). The swing arm (3) is suspended on the support shaft (1) by the suspension rope (4), and the swing arm (3) is in a horizontal state under the action of the counterweight (5) and the thruster (8).

2. The thrust measuring device for a pulsed plasma thruster according to claim 1, characterized in that, The swing arm (3) has a mounting hole, and the support shaft (1) passes through the mounting hole.

3. The thrust measuring device for a pulsed plasma thruster according to claim 1, characterized in that, The upper end of the support shaft (1) is provided with a fixed seat (7), one end of the suspension rope (4) is connected to the fixed seat (7), and the other end is connected to the swing arm (3).

4. The thrust measuring device for a pulsed plasma thruster according to claim 3, characterized in that, The swing arm (3) is provided with a Litz wire (2), which supplies power to the thruster (8).

5. The thrust measuring device for a pulsed plasma thruster according to claim 4, characterized in that, The connection point between the suspension rope (4) and the fixed seat (7) is the fulcrum (9), and the Litz line (2) is connected to the fulcrum (9).

6. A method for measuring the thrust of a pulsed plasma thruster according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Before the thruster ignites, record the oscillation process of the swing arm, calculate the interval between the two peak values ​​of the thruster's oscillation displacement, and record it as the system's natural period. ; S2: The thruster ignites to generate thrust, which applies torque to the swing arm, causing the swing arm to deflect. Record the linear displacement d of the swing arm when the thruster deflects. e ; S3: Calculate the thrust T of the thruster: J—Moment of inertia of the thruster about the fulcrum; d e —The linear displacement of the swing arm when the thruster generates thrust; L—the distance between the thrust center of the thruster and the fulcrum; —The natural cycle of the system.

7. The method according to claim 6, characterized in that, The camera recorded the natural oscillation process of the thruster when it was not ignited and the oscillation process when it was ignited. Then, by analyzing the photos, the magnitude of the swing arm swing value was measured using a scale relationship.

8. The method according to claim 6, characterized in that, In step S1, the natural oscillation process of the thruster is recorded before ignition, and the violent oscillation process of the thruster is recorded after ignition. The linear displacement d of the swing arm is also recorded. e It is the difference between the equilibrium position of the thruster during violent oscillation and the equilibrium position of the thruster during natural oscillation.

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