Test structure of pipeline integrated attitude control rocket engine thrust and working method thereof

Abstract

The application discloses a pipeline integrated attitude control rocket engine thrust test structure and a working method thereof, and belongs to the technical field of sensing, control and measurement. The test structure is composed of a front fixed frame, a rear fixed frame, a rear movable frame, a middle layer movable frame, a front movable frame, a straight connecting beam, a front end inclined connecting beam, a propellant supply pipeline, a rear end inclined connecting beam, a sensitive beam, a film sensor and a supporting thin beam. The rocket jet generates thrust to cause displacement of the engine and the adapter frame, and then drives a series of structures from the front movable frame to the rear movable frame to gradually move along the horizontal direction, so that the strain function film layers of the four film sensors on the sensitive beam are deformed, and finally, the differential Wheatstone bridge composed of the circuit board is tested. The film sensor and the propellant supply pipeline are integrated on the test structure, the "S-shaped" propellant supply pipeline, the circular truncated cone movable frame structure and the layered overall structure are designed, the sensitivity of the test sensor is significantly increased while the rigidity of the test device is ensured.

Description

Technical Field

[0001] This invention belongs to the field of sensing and control technology, specifically relating to a test structure and working method for the thrust of a pipeline-integrated attitude control rocket engine. Background Technology

[0002] Space engines are the core power source for all spacecraft, and thrust testing is a key performance indicator for space engine performance. Thrust testing provides a basis for refining space engine control strategies and adjusting assembly precision. Liquid attitude control rocket engines are responsible for tasks such as attitude adjustment, precise positioning, rapid maneuvering, rendezvous and docking, and separation braking. The accuracy of their thrust testing directly affects flight control precision and target hit accuracy; therefore, thrust testing is essential.

[0003] In the thrust test of the attitude control rocket engine, one end of the propellant supply line is directly connected to the engine, and the other end is fixed to the outside. The thrust generated during ignition causes the attitude control rocket engine to shift. At this time, the propellant supply line constrains the displacement of the attitude control rocket engine, and this constraint force "consumes" some of the thrust. As a result, the thrust measured in the laboratory cannot accurately reflect the thrust of the attitude control rocket engine during actual operation. In addition to steady-state thrust testing, dynamic thrust testing of the attitude control rocket engine is also required. During operation, the pulse ignition frequency of the attitude control rocket engine can reach 50Hz. However, in order to ensure the accuracy of lateral thrust, the thrust testing device has localized areas of weak strength, which may break under high-frequency alternating loads, making measurement impossible. At the same time, due to the complex structure of the propellant supply line, its overall stiffness is poor and its stress state is unstable. Under high-frequency alternating loads, the thrust measured by the sensor will be severely distorted. Existing thrust testing structures typically connect the moving and stationary frames, and the moving frame and propellant supply lines, using linkages and threads. This requires high assembly precision, and assembly errors significantly impact small thrust measurements. Therefore, a novel thrust testing structure is needed to greatly reduce constraints on the propellant supply lines, improve overall stiffness, and minimize the impact of high-frequency alternating loads and assembly errors on thrust testing, thereby enhancing the accuracy of rocket engine thrust testing. Summary of the Invention

[0004] This invention provides a pipeline-integrated thrust testing structure and its working method for an attitude control rocket engine, solving the problems of pipeline constraints, easy breakage at weak points, high assembly accuracy requirements, and poor frequency response performance in the thrust testing device described in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a pipeline-integrated attitude control rocket engine thrust testing structure, including a thrust testing frame and a thin-film sensor. The thrust testing frame includes a propellant supply pipeline, a fixed frame structure, and a moving frame structure located inside the fixed frame structure. The fixed frame structure includes a front fixed frame and a rear fixed frame fixedly connected. The moving frame structure includes a front moving frame, a middle moving frame, and a rear moving frame fixedly connected in sequence. The two ends of the propellant supply pipeline are fixedly connected to the front fixed frame and the front moving frame, respectively, and communicate with pipeline through holes opened on the front fixed frame and the front moving frame. Two sensitive beams are symmetrically distributed between the rear moving frame and the rear fixed frame. The sensitive beams have two grooves, and a thin-film sensor is fabricated on the top surface of the groove.

[0007] Furthermore, the front moving frame, the middle moving frame, and the rear moving frame are all circular ring structures, and their inner and outer diameters increase sequentially.

[0008] Furthermore, the front moving frame and the middle moving frame are fixedly connected by multiple front-end oblique connecting beams, and the middle moving frame and the rear moving frame are fixedly connected by multiple rear-end oblique connecting beams.

[0009] Furthermore, the thrust test fixture is processed into an integrated structure using selective laser melting.

[0010] Furthermore, the propellant supply pipeline is an S-shaped pipeline.

[0011] Furthermore, the front fixed frame and the rear fixed frame are fixedly connected by multiple straight connecting beams, and two supporting thin beams are symmetrically connected between the straight connecting beams and the middle moving frame.

[0012] Furthermore, the sensitive beam is arranged vertically, with an angle of 90° between it and the supporting thin beam.

[0013] Furthermore, the through-holes on the forward moving frame are L-shaped, with one end connected to the propellant supply line and the other end extending to the front surface of the forward moving frame.

[0014] Furthermore, the thin-film sensor includes an insulating layer, on which a strain gauge is disposed, and on which a protective layer and a metal electrode are disposed.

[0015] Secondly, the present invention provides a method for operating a pipeline-integrated attitude control rocket engine thrust testing structure, comprising:

[0016] Fuel and oxidizer flow into the propellant supply line through external pipes and through-holes in the front frame, then flow out from the front surface of the front moving frame and into the engine combustion chamber through another external pipe;

[0017] Fuel and oxidizer are burned in the engine combustion chamber at different flow rates;

[0018] After combustion, the exhaust gas at the engine tail generates a reverse thrust, causing displacement between the engine and the adapter frame. This displacement, in turn, causes the frame structure to move horizontally. The relative displacement between the rear moving frame and the rear stationary frame causes deformation of the connected sensitive beam. In the four stress concentration areas of the two sensitive beams, the two areas closer to the rear moving frame are subjected to tensile stress in the vertical direction, while the two areas farther away from the rear moving frame are subjected to compressive stress in the vertical direction. The stress in the different stress concentration areas causes corresponding deformation of the strain wire grids of the four thin-film sensors fabricated on the sensitive beam, and the resistance of the alloy wire grid in the strain wire grid changes accordingly.

[0019] A flexible circuit board is attached to the rear surface of the sensitive beam. Four thin-film sensors are connected sequentially through the circuit in the flexible circuit board to form a bridge. A DC voltage is applied between two opposite nodes in the bridge. The tension resistor will form a high potential difference across its two ends due to the increase in resistance, while the compression resistor will form a low potential difference across its two ends due to the decrease in resistance, thus forming a differential Wheatstone bridge. A voltmeter is connected between the other two opposite nodes in the bridge circuit to record the output voltage.

[0020] The thrust load generated by the attitude control rocket engine is calculated by using the output voltage.

[0021] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0022] The pipeline-integrated thrust test structure for attitude control rocket engines provided by this invention integrates the propellant supply pipeline and test components into a single thrust test frame, simplifying the overall structure and reducing the impact of assembly errors on testing. Simultaneously, when the engine ignites and generates displacement, the propellant supply pipeline can move along with the test frame, transferring the constraint of the propellant supply pipeline on the engine to the test frame, greatly reducing the impact of pipeline constraints on thrust testing. While increasing the overall stiffness of the thrust test structure improves its frequency response performance, it inevitably reduces its deformation, leading to a decrease in sensor sensitivity. Therefore, the frequency response performance and test sensitivity of the thrust test structure are two contradictory indicators.

[0023] This invention employs an "S-shaped" structural design for the propellant supply pipeline, which, compared to the traditional "straight" pipeline, appropriately reduces its stiffness and increases the deformation of the sensitive structure. By designing a three-layer moving frame, the propellant supply pipeline, supporting beams, and sensitive beams are arranged in separate layers. Compared to a single-layer arrangement, this increases the deformation of the sensitive structure while maintaining overall structural stiffness. Furthermore, by designing the three-layer moving frame as a frustum-shaped frame structure, with the diameter of the moving frame gradually increasing from the front to the rear, and utilizing the linkage principle to amplify the displacement of the moving frame, the invention significantly increases the test sensitivity while ensuring high rigidity of the test structure.

[0024] Furthermore, by using thin-film fabrication technology to integrate the test sensor onto the surface of the sensitive beam, there is no need for additional external sensors. The overall structure is simple and compact, which not only reduces the stress transfer process of traditional bonded strain gauges, but also reduces the weight of the entire test structure and improves the stiffness and resistance to high-frequency alternating loads. Attached Figure Description

[0025] Figure 1 Three-dimensional model of a pipeline-integrated attitude control rocket engine thrust test structure Figure 1 ;

[0026] Figure 2 Three-dimensional model of a pipeline-integrated attitude control rocket engine thrust test structure Figure 2 ;

[0027] Figure 3 Cross-sectional view of the front stationary frame, front moving frame, and propellant supply piping;

[0028] Figure 4 This is a cross-sectional view of the "L-shaped" pipe through-hole of the front moving frame;

[0029] Figure 5 Cross-sectional diagram of the propellant supply pipeline;

[0030] Figure 6 A 3D diagram of the sensitive beam structure;

[0031] Figure 7 This is a cross-sectional view of the sensitive beam groove structure;

[0032] Figure 8 A cross-sectional view of the thrust test structure for a pipeline-integrated attitude control rocket engine.

[0033] Figure 9 This is a schematic diagram of a thin-film sensor structure.

[0034] In the attached diagram, 1. Front fixed frame; 2. Rear fixed frame; 3. Rear moving frame; 4. Middle moving frame; 5. Front moving frame; 6. Straight connecting beam; 7. Front oblique connecting beam; 8. Propellant supply pipeline; 9. Rear oblique connecting beam; 10. Sensing beam; 11. Thin-film sensor; 12. Supporting thin beam; 13. SiO2 insulating layer; 14. Strain gauge; 15. Protective layer; 16. Metal electrode. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0036] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0037] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or may be interposed with another element. The terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., used herein to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] Example 1

[0040] Reference Figures 1 to 8 This embodiment provides a pipeline-integrated attitude control rocket engine thrust test structure, which includes an integrated thrust test frame consisting of a front fixed frame 1, a rear fixed frame 2, a front moving frame 5, a middle moving frame 4, a rear moving frame 3, eight straight connecting beams 6, six front oblique connecting beams 7, a propellant supply pipeline 8, six rear oblique connecting beams 9, two sensitive beams 10 and two supporting thin beams 12, as well as four thin film sensors 11.

[0041] The front moving frame 5, the middle moving frame 4, and the rear moving frame 3 form a three-layer moving frame, which is located inside the front fixed frame 1 and the rear fixed frame 2.

[0042] Both the front fixed frame 1 and the rear fixed frame 2 are annular bosses, each with eight identical circular bolt holes. During testing, bolts are passed through these holes to connect the frame to the test bench. The front surfaces of the front fixed frame 1 and the front moving frame 5 are located in the same plane.

[0043] The centers of the front fixed frame 1 and the rear fixed frame 2 are aligned on a straight line. They are connected by eight straight connecting beams 6, which are perpendicular to both frames to ensure sufficient rigidity of the thrust test frame. The front moving frame 5 and the rear moving frame 3 are both annular structures, while the middle moving frame 4 is a frustum-shaped annular structure. The centers of the three moving frames are aligned on a straight line, and the inner and outer diameters of their rings gradually increase from front to back. The ratio of the outer diameter of the last ring to that of the first ring is more than 1.5 times. The front moving frame 5 and the middle moving frame 4 are fixedly connected by six front-end oblique connecting beams 7, and the middle moving frame 4 and the rear moving frame 3 are fixedly connected by six rear-end oblique connecting beams 9. The six front-end oblique connecting beams 7 and the six rear-end oblique connecting beams 9 are arranged on the same six oblique surfaces. The overall structure of the three moving frames is a frustum-shaped frame structure.

[0044] Two "L-shaped" moving frame pipe through holes are machined on the front moving frame 5. One end of the moving frame pipe through hole is connected to the propellant supply pipe 8, and the other end extends to the front surface of the front moving frame 5. An adapter is welded at the moving frame pipe through hole on the front surface and the pipe is connected to the combustion chamber of the attitude control rocket engine. At the same time, there are also four circular bolt through holes distributed on the front moving frame 5. The second bolt through hole is used to connect to the adapter and the attitude control rocket engine through bolts.

[0045] Two "S-shaped" propellant supply lines 8 are designed between the front stationary frame 1 and the front moving frame 5. The external cross-section of the propellant supply line 8 is rectangular, and the internal cross-section is a circular through hole with a diameter of 6mm. Two square bosses are symmetrically distributed horizontally on the outer wall of the front stationary frame 1. The center of each boss has a circular boss pipe through hole, which penetrates the side wall of the front stationary frame 1 and connects to the "S-shaped" propellant supply lines 8. An adapter is welded at the boss pipe through hole to connect to the external pipelines, which are connected to the external fuel and oxidizer supply ends, respectively. Semi-circular bosses are distributed at a 45° angle to the horizontal direction on the outer wall of the front stationary frame 1. These four semi-circular bosses are used to cooperate with the jigs used during grinding.

[0046] Two supporting thin beams 12 are symmetrically connected between the middle moving frame 4 and the straight connecting beam 6. The supporting thin beams are arranged in the middle of the middle moving frame 4 in a horizontal direction.

[0047] Two rectangular sensing beams 10 are symmetrically distributed between the rear moving frame 3 and the rear fixed frame 2. The sensing beams 10 are arranged vertically, forming a 90° angle with the supporting thin beam 12. The rear end surfaces of the sensing beams 10, the rear moving frame 3, and the rear fixed frame 2 are on the same plane. Each sensing beam 10 has two rectangular grooves formed to create stress concentration areas, on which thin-film sensors 11 are fabricated. A flexible circuit board is attached to the rear end surface of the sensing beams 10, and its electrodes are connected to the metal electrodes 16 of the four thin-film sensors 11 by gold wire bonding. Finally, the circuit in the flexible circuit board connects the four thin-film sensors 11 sequentially to form a bridge circuit.

[0048] Reference Figure 9 The thin-film sensor 11 includes a SiO2 insulating layer 13, a strain wire grid 14 disposed on the SiO2 insulating layer 13, a protective layer 15 and a metal electrode 16 disposed on the strain wire grid 14.

[0049] The rear moving frame 3 has six circular bolt through holes evenly distributed. The thrust test structure is connected to the thrust calibration device through the bolt through holes and bolts, and is used for thrust calibration and standardization of the thrust test frame.

[0050] Example 2

[0051] Reference Figure 9 This embodiment provides a method for fabricating a thin-film sensor as follows:

[0052] Step 1: Surface treatment of the sensitive beam. The rear end surface of the sensitive beam 10 is processed by rough grinding, fine grinding and polishing to ensure that the surface roughness after polishing is below 20nm and there are no micron-level pits and scratches.

[0053] Step 2, Insulation layer preparation. A 2-3 μm thick SiO2 insulation layer 13 is prepared on the rear surface of the stress concentration region of the sensitive beam 10 by magnetron sputtering.

[0054] Step 3: Fabrication of the strain functional film. A femtosecond laser is used to fabricate a wire grid pattern masking layer on a composite flexible thin film. After fabrication, the flexible mask is transferred to the stress concentration area, and a 200-300 nm Karma alloy thin film is deposited on the surface of the SiO2 insulating layer 13 by magnetron sputtering. Finally, the mask is peeled off to obtain the strain wire grid 14 with the target pattern structure.

[0055] Step 4: Electrode and Protective Layer Fabrication. Using flexible masking technology and magnetron sputtering, metal electrodes 16 and a SiO2 protective layer 15 are fabricated on the surface of the strain wire grid 14. After fabrication, a flexible circuit board is attached to the rear end surface of the sensing beam 10. Gold wire bonding technology is used to connect the metal electrodes 16 to the gold electrodes of the flexible circuit board. Finally, the circuitry in the flexible circuit board sequentially connects the four thin-film sensors 11 to form a differential Wheatstone bridge for signal output.

[0056] Example 3

[0057] The working process of the pipeline-integrated attitude control rocket engine thrust test structure described in Example 1 is as follows:

[0058] The external fuel supply end and oxidizer supply end respectively deliver fuel and oxidizer through external pipelines and the adapter at the side end of the front fixed frame 1, from the front fixed frame 1 into the propellant supply pipeline 8, and then out from the front end surface of the front moving frame 5, through the adapter and another external pipeline, and finally into the engine combustion chamber;

[0059] Fuel and oxidizer are burned in the engine combustion chamber at different flow rates. After combustion, the exhaust gas at the engine tail generates reverse thrust, causing displacement of the engine and the adapter frame. This, in turn, drives the front moving frame 5, the six front inclined connecting beams 7, the middle moving frame 4, the six rear inclined connecting beams 9, and the rear moving frame 3 to move gradually in the horizontal direction. The relative displacement between the rear moving frame 3 and the rear stationary frame 2 causes deformation of the connected sensitive beam 10. In the four stress concentration areas of the two sensitive beams 10, the two areas closer to the rear moving frame 3 are subjected to tensile stress in the vertical direction, while the two areas farther away from the rear moving frame are subjected to compressive stress in the vertical direction. The stress in different stress concentration areas causes corresponding deformation of the strain wire grids 14 of the four thin-film sensors 11 fabricated on them. The resistance of the strain wire grids 14 changes accordingly, with the resistance of the tension wire grid increasing and the resistance of the compression wire grid decreasing. Four thin-film sensors 11 are connected sequentially to form a Wheatstone bridge via a flexible circuit board attached to the rear surface of the sensitive beam 10, following the principle of "adjacent arms opposite, opposite arms the same". A 5V DC voltage is applied between two opposite nodes in the bridge. The tension resistor will form a high potential difference across its ends due to the increased resistance, while the compression resistor will form a low potential difference across its ends due to the decreased resistance, thus forming a differential Wheatstone bridge. A voltmeter is connected between the other two opposite nodes in the bridge circuit to record the output voltage. Before testing, a linear correspondence between the output voltage and the thrust load is established using a standard mechanical sensor on the thrust calibration device. During the final test, the thrust load generated by the attitude control rocket engine is obtained by recording the output voltage.

[0060] The term "constituting of" in describing a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, parts, or steps herein also contemplates embodiments that are essentially composed of such elements, components, parts, or steps. The use of the term "may" herein is intended to indicate that any described attribute included by "may" is optional.

[0061] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0062] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A test structure for the thrust of a pipeline-integrated attitude control rocket engine, characterized in that, The device includes a thrust test frame and a thin-film sensor (11). The thrust test frame includes a propellant supply line (8), a fixed frame structure, and a moving frame structure located inside the fixed frame structure. The fixed frame structure includes a front fixed frame (1) and a rear fixed frame (2) that are fixedly connected. The moving frame structure includes a front moving frame (5), a middle moving frame (4), and a rear moving frame (3) that are fixedly connected in sequence. The propellant supply pipeline (8) is fixedly connected at both ends to the front fixed frame (1) and the front moving frame (5), and is connected to the pipeline through holes opened on the front fixed frame (1) and the front moving frame (5); Two sensitive beams (10) are symmetrically distributed between the rear moving frame (3) and the rear fixed frame (2). The sensitive beams (10) have two grooves, and a thin film sensor (11) is prepared on the top surface of the groove. The front moving frame (5) and the middle moving frame (4) are fixedly connected by multiple front-end oblique connecting beams (7), and the middle moving frame (4) and the rear moving frame (3) are fixedly connected by multiple rear-end oblique connecting beams (9). The propellant supply pipeline (8) is an S-shaped pipeline; The front fixed frame (1) and the rear fixed frame (2) are fixedly connected by multiple straight connecting beams (6), and the straight connecting beams (6) and the middle moving frame (4) are symmetrically connected by two supporting thin beams (12).

2. The pipeline-integrated attitude control rocket engine thrust test structure according to claim 1, characterized in that, The front moving frame (5), the middle moving frame (4) and the rear moving frame (3) are all circular ring structures, and their inner and outer diameters increase sequentially.

3. The pipeline-integrated attitude control rocket engine thrust test structure according to claim 1, characterized in that, The thrust test frame is manufactured into an integrated structure by selective laser melting.

4. The test structure for the thrust of the pipeline-integrated attitude control rocket engine according to claim 1, characterized in that, The sensitive beam (10) is arranged vertically, and the angle between it and the supporting thin beam (12) is 90°.

5. The pipeline-integrated attitude control rocket engine thrust test structure according to claim 1, characterized in that, The through hole on the front moving frame (5) is L-shaped. One end of the through hole is connected to the propellant supply pipe (8), and the other end extends to the front surface of the front moving frame (5).

6. The pipeline-integrated attitude control rocket engine thrust test structure according to claim 1, characterized in that, The thin-film sensor (11) includes an insulating layer, on which a strain wire grid (14) is disposed, and on which a protective layer (15) and a metal electrode (16) are disposed.

7. The operating method of the pipeline-integrated attitude control rocket engine thrust test structure according to any one of claims 1 to 6, characterized in that, include: Fuel and oxidizer flow into the propellant supply line (8) through external pipes and through-holes in the front frame (1), then flow out from the front surface of the front moving frame (5) and into the engine combustion chamber through another external pipe; Fuel and oxidizer are burned in the engine combustion chamber at different flow rates; After combustion, the exhaust gas at the tail end of the engine generates a reverse thrust, causing the engine and the adapter to shift, which in turn drives the frame structure to move in the horizontal direction. The relative displacement between the rear moving frame (3) and the rear fixed frame (2) causes the connected sensitive beam (10) to deform. In the four stress concentration areas of the two sensitive beams (10), the two areas closer to the rear moving frame (3) are subjected to tensile stress in the vertical direction, while the two areas farther away from the rear moving frame (3) are subjected to compressive stress in the vertical direction. The stress in different stress concentration areas causes the strain wire grids (14) of the four thin film sensors (11) prepared on the sensitive beam (10) to deform accordingly, and the resistance of the alloy wire grid in the strain wire grid (14) changes accordingly. The flexible circuit board is attached to the rear surface of the sensitive beam (10). The four thin film sensors (11) are connected in sequence through the circuit in the flexible circuit board to form a bridge. A DC voltage is applied between two opposite nodes in the bridge. The tension resistor will form a high potential difference at both ends due to the increase in resistance, while the compression resistor will form a low potential difference at both ends due to the decrease in resistance, thus forming a differential Wheatstone bridge. A voltmeter is connected between the other two opposite nodes in the bridge circuit to record the output voltage. The thrust load generated by the attitude control rocket engine is calculated by using the output voltage.

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