A lunar gravimeter sensor based on metallic zero-length springs

Abstract

A kind of metal zero-length spring-based lunar gravimeter sensor, the metal zero-length spring-based lunar gravimeter sensor includes body frame, metal zero-length spring, spring suspension limiting mechanism, spring capacitance micrometer mechanism, spring pendulum locking mechanism and falling body compensation weight mechanism;Metal zero-length spring middle section is equipped with spring middle support, bottom is connected with spring pendulum lower end;Spring pendulum bottom outside is provided with feedback coil, bottom is clamped permanent magnet;Metal zero-length spring penetrates micrometer upper fixed piece, micrometer moving piece and micrometer lower fixed piece;Vertical stud lower end outside is connected with annular pressure jaw, annular pressure jaw is movably arranged in vertical gear support and is in contact with spring pendulum;Clamping gear motor is engaged with first clamping gear and second clamping gear, second clamping gear is installed by clamping gear support column, falling body clamping rod is clamped with falling body compensation block.The present application can realize automatic, high-precision relative gravity measurement on the surface of the moon.

Description

Technical Field

[0001] This application relates to an improvement in a high-precision relative gravity field measurement technology in the field of planetary gravity science, belonging to the field of relative gravity measurement, and particularly to a lunar gravimeter sensor based on a zero-length metal spring. Background Technology

[0002] The lunar gravity field and its variations comprehensively reflect the distribution and migration processes of mass within the Moon, which is of great significance for lunar resource exploration and internal dynamics research. In-situ gravity measurement on the lunar surface is the most direct technical means of lunar exploration, and the lunar gravimeter is the core equipment for this method.

[0003] While existing superconducting gravimeters and quantum gravimeters offer high accuracy, they are heavy and primarily designed for Earth environments, making them ill-suited for the lunar and outer space environments. Quartz spring gravimeters are small and lightweight, but quartz springs are fragile and pose a significant risk of damage during space transport. Furthermore, the evaporation of quartz in the lunar environment can shorten the instrument's lifespan. The zero-length metal spring relative gravimeter, using a constant-elasticity alloy, offers advantages in size, power consumption, portability, and reliability, making it more suitable as a key technological device for lunar relative gravity measurement.

[0004] Due to the significant differences between the lunar surface topography, temperature environment, and gravitational field characteristics and those of Earth, spring-type lunar gravimeters require drastically different design schemes and approaches compared to terrestrial gravimeters. In particular, to address interference factors such as large-scale temperature fluctuations and environmental vibration disturbances on the lunar surface, the gravimeter sensor needs unique designs in key technologies such as zero-length springs, spring damping limit devices, and spring mass release mechanisms to meet the needs of automated and high-precision relative gravity measurement tasks on the lunar surface.

[0005] Chinese patent application CN201710305509.0, filed on May 3, 2017, discloses a high-precision absolute relative gravity measuring instrument driven by optical force, including a first laser, a collimating and expanding beam system, a reflector, a first beam splitter, a second beam splitter, a falling prism, a reference prism, a photodetector, a second laser, a steering lens, a focusing lens, and a four-quadrant detector; between the second laser and the steering lens is a hollow photonic crystal fiber optic trap system, in which microparticles are placed; the above device utilizes the optical force effect to achieve high-precision gravitational acceleration, and while accurately measuring gravitational acceleration, the dynamic range of the measurement is wider; however, the above scheme still cannot perform automated, high-precision relative gravity measurement on the lunar surface. Summary of the Invention

[0006] The purpose of this application is to overcome the problem that existing technologies cannot perform automated and high-precision relative gravity measurements on the lunar surface, and to provide a lunar gravimeter sensor based on a zero-length metal spring that enables automated and high-precision relative gravity measurements on the lunar surface.

[0007] To achieve the above objectives, the technical solution of this application is: a lunar gravimeter sensor based on a zero-length metal spring, wherein the lunar gravimeter sensor based on a zero-length metal spring includes a main frame, a zero-length metal spring, a spring suspension limiting mechanism, a spring capacitance micrometer mechanism, a spring pendulum locking mechanism, and a fall compensation weight-increasing mechanism.

[0008] The spring suspension limiting mechanism includes an upper spring support, an upper spring wire, a spring wire seat, a spring pendulum, and a permanent magnet. The upper spring support is installed on the top of the inner wall of the main frame. The bottom of the upper spring support is connected to the top of the upper spring wire. The bottom of the upper spring wire is connected to the top of the spring wire seat. The bottom of the spring wire seat is connected to the top of the zero-length metal spring. A middle spring support is provided in the middle section of the zero-length metal spring. The bottom of the zero-length metal spring is connected to the lower end of the spring pendulum. A feedback coil is provided on the outer side of the bottom of the spring pendulum. The bottom of the spring pendulum is engaged with the top of the permanent magnet. The bottom of the permanent magnet is connected to the bottom of the inner wall of the main frame. The outer side of the lower end of the spring pendulum is connected to one end of a plurality of limiting damping leaf springs. The other end of the limiting damping leaf springs is connected to the side of the inner wall of the main frame.

[0009] The spring-capacitance micrometer mechanism includes multiple suspension studs, a moving plate fixing ring, an upper micrometer fixed plate, a moving micrometer, and a lower micrometer fixed plate. The tops of the multiple suspension studs pass through the main frame and are connected by nuts. The bottoms of the multiple suspension studs pass through the upper micrometer fixed plate and the lower micrometer fixed plate in sequence and are connected by suspension nuts. The bottom of the moving plate fixing ring is connected to the top of the spring pendulum, and the top of the moving plate fixing ring is bonded to the bottom of the moving micrometer. The moving micrometer is positioned between the upper micrometer fixed plate and the lower micrometer fixed plate. A zero-length metal spring passes through the upper micrometer fixed plate, the moving micrometer, and the lower micrometer fixed plate in sequence.

[0010] The spring pendulum locking mechanism includes a vertical stud, a locking motor, and a vertical gear. A clamping bracket is installed at the bottom of the inner wall of the main frame. The locking motor is located inside the clamping bracket. The output shaft of the locking motor is connected to the inner ring of the locking gear. The locking gear meshes with the vertical gear. The internal thread of the vertical gear engages with the external thread of the vertical stud. The vertical stud is movably mounted on the vertical gear support. The vertical gear support is installed at the bottom of the inner wall of the main frame. A vertical gear pressure ring is provided at the top of the vertical gear support. The outer side of the lower end of the vertical stud is connected to the inner ring of the vertical gear pressure ring. The outer side of the lower end of the vertical stud is connected to an annular pressure claw. The annular pressure claw is movably connected to the vertical gear support. The other end of the annular pressure claw contacts the spring pendulum. The annular pressure claw moves longitudinally with the vertical stud.

[0011] The weight-increasing mechanism for falling weight compensation includes a falling weight compensation block, falling weight clamping rods, a first clamping gear, and a clamping gear motor. The bottom of the clamping gear motor is connected to the top of the micrometer upper fixed plate, and the output shaft of the clamping gear motor is connected to the inner ring of the first clamping gear. The first clamping gear meshes with a second clamping gear, and the inner ring of the second clamping gear is connected to a clamping gear support column. The clamping gear support column is installed on the top of the micrometer upper fixed plate. Falling weight clamping rods are provided on the top of both the first and second clamping gears. The two falling weight clamping rods are clamped and engaged with the falling weight compensation block. The falling weight compensation block moves longitudinally with the two falling weight clamping rods, and the bottom of the falling weight compensation block engages with the top of the spring pendulum.

[0012] The metal zero-length spring includes a first zero-length spring and a second zero-length spring, which are connected by a spring support.

[0013] The first zero-length spring is made of a spring with a positive temperature coefficient, and the second zero-length spring is made of a spring with a negative temperature coefficient. The absolute values ​​of the first zero-length spring and the second zero-length spring are equal, and the stiffness, length, mean diameter, and wire diameter of the first zero-length spring and the second zero-length spring are all the same.

[0014] The spring support includes an upper end plate, a lower end plate, and multiple triangular prisms. The bottom of the upper end plate and the top of the lower end plate are connected by multiple triangular prisms, which are arranged at equal intervals.

[0015] The top of the upper end plate is connected to the bottom of the first zero-length spring, and the bottom of the lower end plate is connected to the top of the second zero-length spring.

[0016] The spring pendulum includes a first mass, a connecting section, and a second mass. The bottom of the first mass is connected to the top of the connecting section. A zero-length metal spring is sleeved around the outside of the first mass. The bottom of the zero-length metal spring is connected to the top of the connecting section, and the bottom of the connecting section is connected to the top of the second mass.

[0017] The outer perimeter of the connecting section is connected to one end of a plurality of limiting damping leaf springs;

[0018] The top of the second mass body contacts the annular pressure claw, and a slot is provided at the bottom of the second mass body. A permanent magnet is embedded in the slot, and a feedback coil is arranged around the outside of the second mass body.

[0019] The top of the first mass body is provided with a groove, which is fitted into the falling body compensation block.

[0020] The falling body clamping rod includes a first rod, a diagonal rod, a second rod, and a connecting rod. The bottom of the connecting rod is connected to the top of the first clamping gear, the side of the connecting rod is connected to one end of the first rod, the other end of the first rod is connected to one end of the diagonal rod, the other end of the diagonal rod is connected to one end of the second rod, and the second rod is clamped to the falling body compensation block.

[0021] The falling body compensation block includes a falling cylinder and a conical clamping block. The bottom of the falling cylinder is connected to the top of the conical clamping block. The bottom of the conical clamping block is inserted into a groove. A sliding surface is provided on the outer side of the conical clamping block, and a clamping area is formed between the sliding surface and the falling cylinder.

[0022] The second rod is clamped to the clamping area.

[0023] The top of the micrometer upper plate is provided with a clamping gear support, the clamping gear motor is located inside the clamping gear support, and the clamping gear support is connected to the micrometer upper plate by two clamping bolts.

[0024] A stud bushing is fitted on the outside of the suspension stud;

[0025] A mounting sleeve is provided between the upper and lower micrometer mounting plates, and the mounting sleeve is fitted on the outside of the suspension stud.

[0026] The vertical stud includes an upper threaded column and a lower cylinder. The upper threaded column is threadedly engaged with the internal thread of the vertical gear, and the lower cylinder is slidably engaged with the support of the vertical gear. The side of the lower cylinder is connected to one end of the annular pressure claw.

[0027] The vertical gear support includes a hollowed-out lower support, a movable ring, and a connecting column. The top of the lower support is connected to the bottom of the movable ring through the connecting column, and the lower cylinder is movably connected to the movable ring and the lower support in sequence.

[0028] The annular pressure claw is disposed between the lower support and the movable ring;

[0029] The vertical gear pressure ring is installed on the top of the lower support, and the inner ring of the vertical gear pressure ring is connected to the lower end cylinder.

[0030] Compared with the prior art, the beneficial effects of this application are as follows:

[0031] 1. In a lunar gravimeter sensor based on a zero-length metal spring, the spring suspension limiting mechanism includes an upper spring support installed on the top of the inner wall of the main frame, which is sequentially connected to an upper spring wire, a spring wire seat, and the top of the zero-length metal spring; a middle spring support is provided in the middle section of the zero-length metal spring, and the bottom end is connected to the lower end of the spring pendulum; a feedback coil is surrounded on the outer side of the bottom of the spring pendulum, and a permanent magnet is snapped into the bottom. The permanent magnet is fixed to the bottom of the inner wall of the main frame, and the outer side of the lower end of the spring pendulum is connected to the side of the inner wall of the main frame via multiple limiting damping leaf springs. In the spring-capacitance micrometer mechanism, multiple suspension studs pass through the main frame and the upper and lower micrometer fixed plates, and are then fixed with suspension nuts. The bottom of the moving plate fixing ring is connected to the top of the spring pendulum, and the top is bonded to the moving micrometer. The moving micrometer is located between the upper and lower micrometer fixed plates, and a zero-length metal spring passes through all three in sequence. In the spring pendulum locking mechanism, a locking motor is installed inside the clamping bracket at the bottom of the main frame. The locking motor meshes with a vertical gear via a locking gear, and the internal thread of the vertical gear engages with a vertical stud. The stud is movably mounted on the vertical gear support and equipped with a vertical gear pressure ring. Its lower end is connected to an annular pressure claw, which contacts the spring pendulum and moves longitudinally with the vertical stud. In the drop compensation weight-increasing mechanism, the clamping gear motor is located on the top of the micrometer upper fixed plate. It meshes with the second clamping gear via the first clamping gear. The second clamping gear is mounted via a clamping gear support. Drop clamping rods are located on the tops of the two clamping gears, clamping the drop compensation block and causing it to move longitudinally and engage with the top of the spring pendulum. The advantages of this design are as follows:

[0032] First, the sensor senses lunar gravity anomalies through spring elements and converts them into minute displacements. Then, it outputs high-precision gravity signals using high-resolution displacement detection and electromagnetic zero-position measurement. Simultaneously, it incorporates low-gravity compensation, vibration suppression, and launch locking protection measures, enabling the sensor to automatically enter working mode under unattended conditions on the lunar surface and stably complete high-precision relative gravity measurements over a long period of time.

[0033] Secondly, a spring support is set in the middle section of the zero-length metal spring, and the bottom is connected to the spring pendulum. Under the action of gravity, the spring pendulum stably stretches the zero-length metal spring to the working length, forming a highly sensitive spring mass measurement system. The feedback coil and the permanent magnet work together to realize electromagnetic feedback zero-position measurement and expand the dynamic range of the gravimeter. Multiple limiting damping leaf springs are evenly distributed circumferentially between the spring pendulum and the main frame. They can not only limit the radial movement of the spring pendulum, but also provide vertical damping, effectively suppressing lateral disturbances and vertical vibrations, replacing traditional silicone oil damping, avoiding the risk of oil leakage and reducing the weight of the instrument.

[0034] Thirdly, the micrometer moving plate is connected to the top of the spring pendulum body through the moving plate fixing ring and is set between the upper micrometer fixed plate and the lower micrometer fixed plate. It converts the small vertical displacement of the spring pendulum body into the difference of the upper and lower capacitance values, realizing non-contact, high sensitivity and high resolution displacement detection, which meets the requirements of high-precision relative gravity measurement on the lunar surface.

[0035] Fourthly, the locking motor drives the vertical stud and the annular pressure claw to press the spring pendulum body through the locking gear and the vertical gear. This can mechanically lock the spring pendulum body during transportation and launch, preventing impact vibration from damaging the measurement system and improving the safety and reliability of the sensor.

[0036] Fifthly, the clamping gear motor controls the engagement or disengagement of the falling compensation block with the top of the spring pendulum through the first clamping gear, the second clamping gear, and two falling clamping rods. This can adjust the equivalent mass of the spring pendulum, compensate for the contraction problem of the metal zero-length spring caused by the low gravity environment on the moon, and enable the sensor to continue to work normally under the low gravity conditions on the lunar surface, thus broadening its environmental adaptability.

[0037] Therefore, this application enables automated, high-precision relative gravity measurements on the lunar surface.

[0038] 2. In this application, a lunar gravimeter sensor based on a zero-length metal spring is proposed. A first zero-length spring and a second zero-length spring are connected in series, and both are made of materials with equal positive and negative temperature coefficients and absolute values. When the lunar surface temperature changes, the expansion and contraction of the two springs due to temperature changes are equal in magnitude and opposite in direction, thus achieving temperature self-compensation. This effectively suppresses the influence of large-scale temperature fluctuations on the spring length and operating state, eliminating the need for a traditional double-layer temperature control system and reducing the sensor's size, weight, and power consumption. The spring support forms a lightweight hollow structure, which reliably connects the upper and lower zero-length springs and facilitates the passage of the moving plate fixing ring and connection to the spring pendulum. This also reduces mass and improves overall structural stability, helping to ensure the axial stiffness and suspension accuracy of the metal zero-length spring during measurement. Therefore, the overall structural stability of this application is high.

[0039] 3. In this application, a lunar gravimeter sensor based on a zero-length metal spring is disclosed. The minute deformation of the spring directly drives the vertical movement of the entire pendulum, ensuring measurement sensitivity and structural compactness. A limiting damping leaf spring simultaneously provides radial limiting and vertical damping for the pendulum, suppressing lateral disturbances and vertical vibrations, replacing traditional silicone oil damping and avoiding oil leakage and weight gain. A permanent magnet is embedded in a slot at the bottom of the second mass, with a feedback coil on its outer side, forming an electromagnetic feedback zero-position measurement system. This allows the pendulum to operate near zero, improving measurement accuracy and dynamic range. Simultaneously, the top of the second mass engages with an annular clamping claw, facilitating mechanical locking during transport and launch. A V-shaped groove is formed on the top of the first mass, automatically centering and engaging with the fall compensation block, facilitating adjustment of the pendulum's equivalent mass to compensate for the low-gravity environment of the lunar surface. This results in a compact sensor structure with high integration, capable of high-precision relative gravity measurement in low-gravity, high-temperature-varying, and vibration-prone environments on the lunar surface. Therefore, this application is suitable for measurements in low-gravity, high-temperature-varying, and vibration-prone environments on the lunar surface.

[0040] 4. In this application, a lunar gravimeter sensor based on a zero-length metal spring is described. The falling object clamping rod, through a linkage structure of a connecting rod, a first rod, an inclined rod, and a second rod, can automatically open and close under the drive of a clamping gear, stably clamping or releasing the falling object compensation block. The clamping area formed by the sliding surface and the falling cylinder on the falling object compensation block allows the second rod to move smoothly along the sliding surface during operation, ensuring reliable clamping and facilitating the up-and-down movement of the falling object compensation block. The conical locking block at the bottom of the falling object compensation block automatically centers when it engages with the V-shaped groove at the top of the spring pendulum, ensuring accurate and repeatable loading. By controlling the clamping, lifting, lowering, and embedding of the falling object compensation block through this mechanism, the equivalent mass of the spring pendulum can be adjusted to compensate for spring contraction caused by the low gravity environment of the lunar surface, allowing the sensor to maintain normal operation under lunar surface conditions. Therefore, this application can compensate for spring contraction caused by the low gravity environment of the lunar surface.

[0041] 5. In a lunar gravimeter sensor based on a zero-length metal spring, the vertical stud forms a threaded pair with the internal thread of the vertical gear through the upper threaded column, converting the rotational motion of the vertical gear into the vertical linear motion of the vertical stud; the lower cylinder slides into the vertical gear support, guiding the vertical motion of the vertical stud and ensuring its motion stability; simultaneously, an annular pressure claw is connected to the side of the lower cylinder, allowing the annular pressure claw to move up and down with the vertical stud, thereby applying a pressing or releasing action to the spring pendulum; the vertical gear... The support consists of a hollowed-out lower support, a movable ring, and a connecting column. It supports the vertical stud and provides installation and movement space for the annular pressure claw, while the lower support and movable ring limit the movement of the annular pressure claw. The vertical gear pressure ring is installed on the top of the lower support, with its inner ring connected to the lower cylinder. This constrains the axial position of the vertical gear, ensuring it can only rotate and not move axially. This guarantees the stability of the threaded drive and the reliability of the locking action, thus reliably locking the spring pendulum during transportation and launch, and smoothly unlocking it during operation. Therefore, this application is safe to use and simple to operate. Attached Figure Description

[0042] Figure 1 This is a structural diagram of this application.

[0043] Figure 2 This is the right view of this application.

[0044] Figure 3 This is a cross-sectional view of this application.

[0045] Figure 4 This is a schematic diagram of the spring suspension limiting mechanism in this application.

[0046] Figure 5 This is a schematic diagram of the spring pendulum in this application.

[0047] Figure 6 This is a schematic diagram of the spring-capacitance micrometer mechanism in this application.

[0048] Figure 7 This is a schematic diagram of the spring-loaded locking mechanism in this application.

[0049] Figure 8 This is a schematic diagram of the weight-increasing mechanism for weight compensation in this application.

[0050] Figure 9 It is in this application Figure 1 A sectional view.

[0051] Figure 10 This is a schematic diagram of the free-fall clamping rod in this application.

[0052] Figure 11 This is a schematic diagram of the vertical gear support in this application.

[0053] In the diagram: 1. Main frame; 2. Suspension stud; 3. Stud bushing; 4. Moving plate retaining ring; 5. Fixed plate bushing; 6. Suspension nut; 7. Vertical stud; 71. Upper threaded stud; 72. Lower cylinder; 8. Locking gear; 9. Pressing bracket; 10. Locking motor; 11. Upper spring support; 12. Upper spring wire pull; 13. Spring wire pull seat; 14. Metal zero-length spring; 15. First zero-length spring; 16. Second zero-length spring; 17. Spring pendulum; 18. First mass body; 19. Connecting section; 10. V-groove; 10. Second mass body; 11. Slot; 12. Vertical gear; 13. Vertical gear pressure ring; 14. Vertical gear support; 15. Lower support; 16. Moving ring; 17. Connecting column; 18. Falling compensation block; 19. Falling cylinder. 1. Conical block 192. Sliding surface 193. Clamping area 194. Falling clamping rod 20. First rod 201. Inclined rod 202. Second rod 203. Connecting rod 204. First clamping gear 21. Second clamping gear 211. Clamping gear support 22. Clamping gear support column 23. Clamping gear motor 24. Clamping bolt 25. Annular pressure claw 26. Spring middle support 27. Upper end plate 271. Lower end plate 272. Triangular prism 273. Micrometer upper fixed plate 28. Micrometer moving plate 29. Micrometer lower fixed plate 30. Limiting damping leaf spring 31. Feedback coil 32. Permanent magnet 33. Spring suspension limiting mechanism A. Spring capacitor micrometer mechanism B. Spring pendulum locking mechanism C. Falling compensation weight increase mechanism D. Detailed Implementation

[0054] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] See Figures 1 to 11A lunar gravimeter sensor based on a zero-length metal spring, the lunar gravimeter sensor based on a zero-length metal spring includes a main frame 1, a zero-length metal spring 14, a spring suspension limiting mechanism A, a spring capacitance micrometer mechanism B, a spring pendulum locking mechanism C, and a fall compensation weight-increasing mechanism D.

[0056] The spring suspension limiting mechanism A includes an upper spring support 11, an upper spring wire 12, a spring wire seat 13, a spring pendulum 15, and a permanent magnet 33. The upper spring support 11 is installed on the top of the inner wall of the main frame 1. The bottom of the upper spring support 11 is connected to the top of the upper spring wire 12. The bottom of the upper spring wire 12 is connected to the top of the spring wire seat 13. The bottom of the spring wire seat 13 is connected to the top of the zero-length metal spring 14. A middle spring support 27 is provided in the middle section of the zero-length metal spring 14. The bottom of the zero-length metal spring 14 is connected to the lower end of the spring pendulum 15. A feedback coil 32 is provided on the outer side of the bottom of the spring pendulum 15. The bottom of the spring pendulum 15 is engaged with the top of the permanent magnet 33. The bottom of the permanent magnet 33 is connected to the bottom of the inner wall of the main frame 1. The outer side of the lower end of the spring pendulum 15 is connected to one end of a plurality of limiting damping leaf springs 31. The other end of the limiting damping leaf springs 31 is connected to the side of the inner wall of the main frame 1.

[0057] The spring-capacitance micrometer mechanism B includes multiple suspension studs 2, a movable plate fixing ring 4, an upper micrometer fixed plate 28, a movable micrometer 29, and a lower micrometer fixed plate 30. The tops of the multiple suspension studs 2 pass through the main body frame 1 and are connected by nuts. The bottoms of the multiple suspension studs 2 pass through the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30 in sequence and are connected by suspension nuts 6. The bottom of the movable plate fixing ring 4 is connected to the top of the spring pendulum 15, and the top of the movable plate fixing ring 4 is bonded to the bottom of the movable micrometer 29. The movable micrometer 29 is disposed between the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30. A zero-length metal spring 14 is disposed by passing through the upper micrometer fixed plate 28, the movable micrometer 29, and the lower micrometer fixed plate 30 in sequence.

[0058] The spring pendulum locking mechanism C includes a vertical stud 7, a locking motor 10, and a vertical gear 16. A clamping bracket 9 is installed at the bottom of the inner wall of the main body frame 1. The locking motor 10 is located inside the clamping bracket 9. The output shaft of the locking motor 10 is connected to the inner ring of the locking gear 8. The locking gear 8 meshes with the vertical gear 16. The internal thread of the vertical gear 16 is engaged with the external thread of the vertical stud 7. The vertical stud 7 is movably mounted on the vertical gear support 18. The vertical gear support 18 is installed at the bottom of the inner wall of the main body frame 1. A vertical gear pressure ring 17 is provided at the top of the vertical gear support 18. The outer side of the lower end of the vertical stud 7 is connected to the inner ring of the vertical gear pressure ring 17. The outer side of the lower end of the vertical stud 7 is connected to the annular pressure claw 26. The annular pressure claw 26 is movably connected to the vertical gear support 18. The other end of the annular pressure claw 26 contacts the spring pendulum 15. The annular pressure claw 26 moves longitudinally with the vertical stud 7.

[0059] The free fall compensation weight-increasing mechanism D includes a free fall compensation block 19, a free fall clamping rod 20, a first clamping gear 21, and a clamping gear motor 24. The bottom of the clamping gear motor 24 is connected to the top of the micrometer upper fixed plate 28, and the output shaft of the clamping gear motor 24 is connected to the inner ring of the first clamping gear 21. The first clamping gear 21 meshes with the second clamping gear 211, and the inner ring of the second clamping gear 211 is connected to the clamping gear support 23. The clamping gear support 23 is installed on the top of the micrometer upper fixed plate 28. The tops of the first clamping gear 21 and the second clamping gear 211 are each provided with a free fall clamping rod 20. The two free fall clamping rods 20 are clamped and engaged with the free fall compensation block 19. The free fall compensation block 19 moves longitudinally with the two free fall clamping rods 20, and the bottom of the free fall compensation block 19 is engaged with the top of the spring pendulum 15.

[0060] The metal zero-length spring 14 includes a first zero-length spring 141 and a second zero-length spring 142, which are connected by a spring support 27.

[0061] The first zero-length spring 141 is made of a spring with a positive temperature coefficient, and the second zero-length spring 142 is made of a spring with a negative temperature coefficient. The absolute values ​​of the first zero-length spring 141 and the second zero-length spring 142 are equal, and the stiffness, length, mean diameter, and wire diameter of the first zero-length spring 141 and the second zero-length spring 142 are the same.

[0062] The spring support 27 includes an upper end plate 271, a lower end plate 272 and a plurality of triangular prisms 273. The bottom of the upper end plate 271 and the top of the lower end plate 272 are connected by a plurality of triangular prisms 273, and the plurality of triangular prisms 273 are arranged at equal intervals.

[0063] The top of the upper end plate 271 is connected to the bottom of the first zero-length spring 141, and the bottom of the lower end plate 272 is connected to the top of the second zero-length spring 142.

[0064] The spring pendulum 15 includes a first mass 151, a connecting section 152 and a second mass 154. The bottom of the first mass 151 is connected to the top of the connecting section 152. A zero-length metal spring 14 is sleeved on the outer perimeter of the first mass 151. The bottom of the zero-length metal spring 14 is connected to the top of the connecting section 152, and the bottom of the connecting section 152 is connected to the top of the second mass 154.

[0065] The outer perimeter of the connecting section 152 is connected to one end of a plurality of limiting damping leaf springs 31;

[0066] The top of the second mass body 154 contacts the annular pressure claw 26, and a slot 155 is provided at the bottom of the second mass body 154. The permanent magnet 33 is embedded in the slot 155, and a feedback coil 32 is arranged around the outer side of the second mass body 154.

[0067] The top of the first mass body 151 is provided with a V-shaped groove 153, which is fitted into the fall compensation block 19.

[0068] The falling body clamping rod 20 includes a first rod 201, a diagonal rod 202, a second rod 203, and a connecting rod 204. The bottom of the connecting rod 204 is connected to the top of the first clamping gear 21, the side of the connecting rod 204 is connected to one end of the first rod 201, the other end of the first rod 201 is connected to one end of the diagonal rod 202, the other end of the diagonal rod 202 is connected to one end of the second rod 203, and the second rod 203 is clamped to the falling body compensation block 19.

[0069] The falling body compensation block 19 includes a falling cylinder 191 and a conical locking block 192. The bottom of the falling cylinder 191 is connected to the top of the conical locking block 192. The bottom of the conical locking block 192 is inserted into the V-shaped groove 153. A sliding surface 193 is provided on the outer side of the conical locking block 192. A clamping area 194 is formed between the sliding surface 193 and the falling cylinder 191.

[0070] The second rod 203 is clamped to the clamping area 194.

[0071] The micrometer upper plate 28 is provided with a clamping gear support 22 on its top. The clamping gear motor 24 is located inside the clamping gear support 22. The clamping gear support 22 is connected to the micrometer upper plate 28 by two clamping bolts 25.

[0072] The outer side of the suspension stud 2 is fitted with a stud bushing 3;

[0073] A mounting sleeve 5 is provided between the upper micrometer mounting plate 28 and the lower micrometer mounting plate 30, and the mounting sleeve 5 is sleeved on the outside of the suspension stud 2.

[0074] The vertical stud 7 includes an upper threaded stud 71 and a lower cylinder 72. The upper threaded stud 71 is threadedly engaged with the internal thread of the vertical gear 16, and the lower cylinder 72 is slidably engaged with the vertical gear support 18. The side of the lower cylinder 72 is connected to one end of the annular pressure claw 26.

[0075] The vertical gear support 18 includes a hollowed-out lower support 181, a movable ring 182 and a connecting column 183. The top of the lower support 181 is connected to the bottom of the movable ring 182 through the connecting column 183, and the lower end cylinder 72 is movably connected to the movable ring 182 and the lower support 181 in sequence.

[0076] The annular pressure claw 26 is disposed between the lower support 181 and the movable ring 182;

[0077] The vertical gear pressure ring 17 is installed on the top of the lower support 181, and the inner ring of the vertical gear pressure ring 17 is connected to the lower end cylinder 72.

[0078] The supplementary technical features of this design are as follows:

[0079] The design scheme of the series connection of zero-length metal springs directly solves the problem of the impact of thermal expansion and contraction of the zero-length metal springs on the measurement accuracy of the lunar gravimeter, making the gravimeter sensor lighter and smaller. The elastic spring damping system structure has the functions of radial constraint and strong vertical damping for the zero-length springs. The weight-increasing mechanism D for falling body compensation solves the technical problem of the large difference in gravitational acceleration between the lunar surface and the Earth surface. This allows the zero-length metal spring 14 to maintain its original position and be in normal measurement state after the spring-type lunar gravimeter developed and assembled on the ground is launched to the lunar surface.

[0080] Example 1:

[0081] See Figure 1 —2, A lunar gravimeter sensor based on a zero-length metal spring, the lunar gravimeter sensor based on a zero-length metal spring includes a main frame 1, a zero-length metal spring 14, a spring suspension limiting mechanism A, a spring capacitance micrometer mechanism B, a spring pendulum locking mechanism C, and a fall compensation weight-increasing mechanism D.

[0082] The spring suspension limiting mechanism A includes an upper spring support 11, an upper spring wire 12, a spring wire seat 13, a spring pendulum 15, and a permanent magnet 33. The upper spring support 11 is installed on the top of the inner wall of the main frame 1. The bottom of the upper spring support 11 is connected to the top of the upper spring wire 12. The bottom of the upper spring wire 12 is connected to the top of the spring wire seat 13. The bottom of the spring wire seat 13 is connected to the top of the zero-length metal spring 14. A middle spring support 27 is provided in the middle section of the zero-length metal spring 14. The bottom of the zero-length metal spring 14 is connected to the lower end of the spring pendulum 15. A feedback coil 32 is provided on the outer side of the bottom of the spring pendulum 15. The bottom of the spring pendulum 15 is engaged with the top of the permanent magnet 33. The bottom of the permanent magnet 33 is connected to the bottom of the inner wall of the main frame 1. The outer side of the lower end of the spring pendulum 15 is connected to one end of a plurality of limiting damping leaf springs 31. The other end of the limiting damping leaf springs 31 is connected to the side of the inner wall of the main frame 1.

[0083] The spring-capacitance micrometer mechanism B includes multiple suspension studs 2, a movable plate fixing ring 4, an upper micrometer fixed plate 28, a movable micrometer 29, and a lower micrometer fixed plate 30. The tops of the multiple suspension studs 2 pass through the main body frame 1 and are connected by nuts. The bottoms of the multiple suspension studs 2 pass through the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30 in sequence and are connected by suspension nuts 6. The bottom of the movable plate fixing ring 4 is connected to the top of the spring pendulum 15, and the top of the movable plate fixing ring 4 is bonded to the bottom of the movable micrometer 29. The movable micrometer 29 is disposed between the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30. A zero-length metal spring 14 is disposed by passing through the upper micrometer fixed plate 28, the movable micrometer 29, and the lower micrometer fixed plate 30 in sequence.

[0084] The spring pendulum locking mechanism C includes a vertical stud 7, a locking motor 10, and a vertical gear 16. A clamping bracket 9 is installed at the bottom of the inner wall of the main body frame 1. The locking motor 10 is located inside the clamping bracket 9. The output shaft of the locking motor 10 is connected to the inner ring of the locking gear 8. The locking gear 8 meshes with the vertical gear 16. The internal thread of the vertical gear 16 is engaged with the external thread of the vertical stud 7. The vertical stud 7 is movably mounted on the vertical gear support 18. The vertical gear support 18 is installed at the bottom of the inner wall of the main body frame 1. A vertical gear pressure ring 17 is provided at the top of the vertical gear support 18. The outer side of the lower end of the vertical stud 7 is connected to the inner ring of the vertical gear pressure ring 17. The outer side of the lower end of the vertical stud 7 is connected to the annular pressure claw 26. The annular pressure claw 26 is movably connected to the vertical gear support 18. The other end of the annular pressure claw 26 contacts the spring pendulum 15. The annular pressure claw 26 moves longitudinally with the vertical stud 7.

[0085] The free fall compensation weight-increasing mechanism D includes a free fall compensation block 19, a free fall clamping rod 20, a first clamping gear 21, and a clamping gear motor 24. The bottom of the clamping gear motor 24 is connected to the top of the micrometer upper fixed plate 28, and the output shaft of the clamping gear motor 24 is connected to the inner ring of the first clamping gear 21. The first clamping gear 21 meshes with the second clamping gear 211, and the inner ring of the second clamping gear 211 is connected to the clamping gear support 23. The clamping gear support 23 is installed on the top of the micrometer upper fixed plate 28. The tops of the first clamping gear 21 and the second clamping gear 211 are each provided with a free fall clamping rod 20. The two free fall clamping rods 20 are clamped and engaged with the free fall compensation block 19. The free fall compensation block 19 moves longitudinally with the two free fall clamping rods 20, and the bottom of the free fall compensation block 19 is engaged with the top of the spring pendulum 15.

[0086] In application: During transport, launch, or non-operation, the spring pendulum locking mechanism C, driven by the locking motor 10, rotates the locking gear 8 and the vertical gear 16, causing the vertical stud 7 to move downwards. This, in turn, drives the annular pressure claw 26 to press the spring pendulum 15. Simultaneously, the two falling clamping rods 20 in the falling compensation weight-adding mechanism D hold the falling compensation block 19 and press its bottom into the V-shaped groove 153 on the top of the spring pendulum 15, forming a locking engagement and achieving initial locking protection for the spring pendulum 15. When the sensor is installed on a lunar surface measuring point or on a lander and the main frame 1 is kept stable, the locking motor 10 is started to rotate in the opposite direction. Through the meshing of the locking gear 8 and the vertical gear 16, the spring pendulum 15 is initially locked and protected. The vertical stud 7 moves upward, causing the annular pressure claw 26 to move upward and release the spring pendulum 15 to release the vertical lock. The clamping gear motor 24 drives the first clamping gear 21 and the second clamping gear 211 to rotate, so that the two falling clamping rods 20 maintain the falling compensation block 19 in the engagement state with the V-shaped groove 153 on the top of the spring pendulum 15, or adjust the vertical position of the falling compensation block 19, so that the spring pendulum 15 reaches the working length under the weight of the falling compensation block 19. After unlocking, the metal zero-length spring 14 is vertically stretched to the working state under the gravity of the spring pendulum 15 and the falling compensation block 19. When the lunar gravity field changes slightly, the metal zero-length spring 14 drives the spring pendulum. The spring pendulum 15 generates a vertical displacement. The top of the spring pendulum 15 drives the micrometer moving plate 29 to move between the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30 through the moving plate fixing ring 4. This changes the capacitance value of the spring capacitor micrometer mechanism B and outputs a displacement signal corresponding to the change in gravity. During the measurement process, current can be supplied to the feedback coil 32. The feedback coil 32 interacts with the permanent magnet 33 to generate an electromagnetic force that returns the spring pendulum 15 to the zero position. The feedback current or voltage is recorded to achieve zero-position measurement and expand the range of the gravimeter. If it is necessary to adjust the mass of the spring pendulum 15 to adapt to different gravity environments or measurement ranges, the clamping gear motor 24 is started and the first clamping gear 21 meshes with the second clamping gear 211. The combined action of the two falling clamping rods 20 causes the falling compensation block 19 to move downwards and its conical locking block 192 to embed into the V-shaped groove 153 on the top of the spring pendulum 15 to achieve falling compensation and increase weight. The reverse drive causes the falling compensation block 19 to move upwards and separate from the spring pendulum 15 to reduce mass. After the measurement is completed, the locking motor 10 is started to move the vertical stud 7 downwards, and the annular pressure claw 26 moves downwards to re-press the spring pendulum 15. The clamping gear motor 24 drives the two falling clamping rods 20 to clamp and fix the falling compensation block 19 to prevent it from colliding or misaligning with the spring pendulum 15. The sensor returns to the initial locked protection state, completing a complete lunar gravity measurement process.

[0087] Example 2:

[0088] Example 2 is basically the same as Example 1, except that:

[0089] See Figure 3 —5, the spring suspension limiting mechanism A includes an upper spring support 11, an upper spring wire 12, a spring wire seat 13, a spring pendulum 15, and a permanent magnet 33; the upper spring support 11 is installed on the top of the inner wall of the main frame 1, the bottom of the upper spring support 11 is connected to the top of the upper spring wire 12, the bottom of the upper spring wire 12 is connected to the top of the spring wire seat 13, the bottom of the spring wire seat 13 is connected to the top of the metal zero-length spring 14, a middle spring support 27 is provided in the middle section of the metal zero-length spring 14, the bottom of the metal zero-length spring 14 is connected to the lower end of the spring pendulum 15, a feedback coil 32 is provided on the outer periphery of the bottom of the spring pendulum 15, and the bottom of the spring pendulum 15... The top of the spring pendulum is engaged with the top of the permanent magnet 33, the bottom of the permanent magnet 33 is connected to the bottom of the inner wall of the main body frame 1, the lower outer side of the spring pendulum 15 is connected to one end of a plurality of limiting damping leaf springs 31, and the other end of the limiting damping leaf springs 31 is connected to the side of the inner wall of the main body frame 1; the metal zero-length spring 14 includes a first zero-length spring 141 and a second zero-length spring 142, the first zero-length spring 141 and the second zero-length spring 142 are connected by a spring support 27; the first zero-length spring 141 is made of a positive temperature coefficient spring, the second zero-length spring 142 is made of a negative temperature coefficient spring, the absolute values ​​of the first zero-length spring 141 and the second zero-length spring 142 are equal, the first The zero-length spring 141 and the second zero-length spring 142 have the same stiffness, length, mean diameter, and wire diameter. The spring support 27 includes an upper end plate 271, a lower end plate 272, and multiple triangular prisms 273. The bottom of the upper end plate 271 and the top of the lower end plate 272 are connected by multiple triangular prisms 273, which are equidistant. The top of the upper end plate 271 is connected to the bottom of the first zero-length spring 141, and the bottom of the lower end plate 272 is connected to the top of the second zero-length spring 142. The spring pendulum 15 includes a first mass 151, a connecting section 152, and a second mass 154. The bottom of the first mass 151 is connected to the top of the connecting section 152. A zero-length metal spring 14 is sleeved on the outer perimeter of the first mass 151. The bottom of the zero-length metal spring 14 is connected to the top of the connecting section 152, and the bottom of the connecting section 152 is connected to the top of the second mass 154. The outer perimeter of the connecting section 152 is connected to one end of a plurality of limiting damping leaf springs 31. The top of the second mass 154 contacts the annular pressure claw 26. A slot 155 is provided at the bottom of the second mass 154, and a permanent magnet 33 is embedded in the slot 155. A feedback coil 32 is arranged around the outer perimeter of the second mass 154. A V-shaped groove 153 is provided at the top of the first mass 151, and the V-shaped groove 153 is fitted with the fall compensation block 19.

[0090] In application: The main frame 1 is a hollow cylindrical cavity structure with relatively thin walls, having upper and lower bottom surfaces. A central through-hole is machined on the top surface to secure the cylindrical surface of the upper spring support 11, allowing the metal zero-length spring 14 to be vertically suspended. The core measuring element of the lunar gravimeter sensor is the metal zero-length spring 14, which senses gravity anomalies and undergoes vertical displacement. This minute displacement change is transmitted via the spring-capacitance micrometer mechanism B and output. The metal zero-length spring 14 in this device differs from the spring in terrestrial spring gravimeters, employing a special process... The first zero-length spring 141 and the second zero-length spring 142, which have positive and negative temperature coefficients with equal absolute values, are welded together by the middle spring support 27. The two springs are only different in temperature coefficient, and all other parameters such as stiffness, length, mean diameter, and wire diameter are the same. Such a metal zero-length spring 14 with integrated structure can greatly offset the interference of the large temperature change of the lunar surface on the thermal expansion and contraction of the metal zero-length spring 14 and overcome the technical difficulties of large volume and heavy weight caused by the double-layer temperature control system of the ground gravimeter.

[0091] The spring support 27 is made of lightweight alloy. Under the vertical gravity of the spring pendulum 15, it pulls the metal zero-length spring 14 downward to its working length. The first mass 151 is a cylinder with a diameter slightly smaller than the inner diameter of the metal zero-length spring 14, which is vertically fitted into the second zero-length spring 142. The height of the first mass 151 is slightly longer than that of the second zero-length spring 142. After assembly, its upper end face is located at the middle plane of the spring support 27, which facilitates the bonding and fixing of the moving plate fixing ring passing through the spring support 27. 4. The upper surface of the first mass body 151 has a smooth V-shaped groove 153. This V-shaped groove 153 is sized to match the conical locking block 192 of the fall compensation block 19, serving to support the weight of the embedded fall compensation block 19. At the same time, the outer circular surface of the top of the first mass body 151 is glued to the moving plate fixing ring 4. The moving plate fixing ring 4 can glue the micrometer moving plate 29 and move vertically together with the metal zero-length spring 14. The second mass body 154 is a flat cylinder with a slightly larger diameter and a hollow interior. A feedback coil 32 is formed by winding a certain number of copper wires around a cylindrical surface. A permanent magnet 33 can be embedded in the internal slot 155. The upper surface of the permanent magnet 33 and the inner surface of the slot 155 on the surrounding cylindrical surface are equidistant. This distance is less than the distance between the micrometer 29 and the micrometer lower plate 30, so that the micrometer 29 and the micrometer lower plate 30 do not contact or interfere when the spring pendulum 15 is pressed. When the feedback coil 32 is energized, it can work with the permanent magnet 33 to achieve the purpose of zero-position measurement. Zero-position measurement can increase the range of the gravimeter. Three limiting damping leaf springs 31 are placed at equal angles of 120 degrees radially, and their two ends are respectively fixed to the second mass body 154 and the bottom inner side of the main frame 1. They have the dual function of radial constraint and vertical damping on the metal zero-length spring 14 and the spring pendulum 15, avoiding radial acceleration disturbance and overcoming the cross-coupling effect caused by lateral disturbance. At the same time, the elastic damping greatly reduces the disturbance of vertical acceleration during the relative measurement of the gravimeter and the damage to the instrument's spring mass pendulum system.

[0092] Example 3:

[0093] Example 3 is basically the same as Example 1, except that:

[0094] See Figure 6The spring-capacitance micrometer mechanism B includes multiple suspension studs 2, a movable plate fixing ring 4, an upper micrometer fixed plate 28, a movable micrometer 29, and a lower micrometer fixed plate 30. The tops of the multiple suspension studs 2 pass through the main frame 1 and are connected by nuts. The bottoms of the multiple suspension studs 2 pass through the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30 in sequence and are connected by suspension nuts 6. The bottom of the movable plate fixing ring 4 is connected to the top of the spring pendulum 15, and the top of the movable plate fixing ring 4 is bonded to the bottom of the movable micrometer 29. The movable micrometer 29 is disposed between the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30. A zero-length metal spring 14 is disposed through the upper micrometer fixed plate 28, the movable micrometer 29, and the lower micrometer fixed plate 30 in sequence. A stud bushing 3 is sleeved on the outside of the suspension studs 2. A fixed plate bushing 5 is disposed between the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30, and the fixed plate bushing 5 is sleeved on the outside of the suspension studs 2.

[0095] In application: The stud bushing 3 is fitted outside the suspension stud 2 to adjust the vertical installation distance of the upper micrometer fixed plate 28. The fixed plate bushing 5 is also fitted outside the suspension stud 2 to adjust the center position of the micrometer movable plate 29 to the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30. This is the key adjustment for the initial state of the gravimeter zero-point measurement. The micrometer movable plate 29 is glued to the upper end face of the movable plate fixing ring 4 and moves vertically with the spring pendulum 15. The spring pendulum 15 will be vertically displaced due to gravity anomalies or vertical acceleration disturbances, which will lead to unequal distances between the micrometer movable plate 29 and the upper micrometer fixed plate 28 and the lower micrometer fixed plate 30, thus changing the capacitance of the upper and lower space. This electrical signal is tracked and measured by the data acquisition system, and finally the relative gravity anomaly value is output by converting the instrument displacement and the grid value of the electrical signal.

[0096] Example 4:

[0097] Example 4 is basically the same as Example 1, except that:

[0098] See Figure 7 , Figure 11The spring pendulum locking mechanism C includes a vertical stud 7, a locking motor 10, and a vertical gear 16. A clamping bracket 9 is installed at the bottom of the inner wall of the main frame 1. The locking motor 10 is located within the clamping bracket 9. The output shaft of the locking motor 10 is connected to the inner ring of the locking gear 8. The locking gear 8 meshes with the vertical gear 16. The internal thread of the vertical gear 16 engages with the external thread of the vertical stud 7. The vertical stud 7 is movably mounted on a vertical gear support 18. The vertical gear support 18 is installed at the bottom of the inner wall of the main frame 1. A vertical gear pressure ring 17 is provided at the top of the vertical gear support 18. The outer side of the lower end of the vertical stud 7 is connected to the inner ring of the vertical gear pressure ring 17. The outer side of the lower end of the vertical stud 7 is connected to an annular pressure claw 26. The annular pressure claw 26 is movably connected to the vertical gear support 18. The other end of the annular pressure claw 26 is connected to the spring pendulum. The body 15 contacts the annular pressure claw 26, which moves longitudinally along with the vertical stud 7. The vertical stud 7 includes an upper threaded column 71 and a lower cylinder 72. The upper threaded column 71 is threaded into the internal thread of the vertical gear 16, and the lower cylinder 72 is slidably engaged with the vertical gear support 18. The side of the lower cylinder 72 is connected to one end of the annular pressure claw 26. The vertical gear support 18 includes a hollowed-out lower support 181, a movable ring 182, and a connecting column 183. The top of the lower support 181 is connected to the bottom of the movable ring 182 through the connecting column 183. The lower cylinder 72 is movably connected to the movable ring 182 and the lower support 181 in sequence. The annular pressure claw 26 is disposed between the lower support 181 and the movable ring 182. The vertical gear pressure ring 17 is installed on the top of the lower support 181, and the inner ring of the vertical gear pressure ring 17 is connected to the lower cylinder 72.

[0099] In application: The locking motor 10 drives the locking gear 8 to rotate, and the locking gear 8 meshes with the vertical gear 16. The internal thread of the vertical gear 16 is adapted to the external thread on the surface of the upper threaded column 71. The vertical gear 16 is fixed by the vertical gear pressure ring 17, so that the vertical gear 16 can only rotate. This rotational movement drives the threaded pair to achieve a slow vertical displacement change of the vertical column 7. The vertical gear 16 drives the vertical column 7 to move up and down, thereby guiding the symmetrically distributed annular pressure claws 26 fixed on the lower cylinder 72 to press down against the upper surface of the second mass body 154. This action indirectly achieves the pressing of the top surface of the internal slot 155 of the second mass body 154 against the upper surface of the permanent magnet 33, thereby achieving the locking function of the spring pendulum 15, ensuring that the gravimeter is protected from damage by the impact acceleration of space launch, and ensuring the safety and reliability of the instrument.

[0100] Example 5:

[0101] Example 5 is basically the same as Example 1, except that:

[0102] See Figure 8—10, the freefall compensation and weight-increasing mechanism D includes a freefall compensation block 19, a freefall clamping rod 20, a first clamping gear 21, and a clamping gear motor 24; the bottom of the clamping gear motor 24 is connected to the top of the micrometer upper fixed plate 28, the output shaft of the clamping gear motor 24 is connected to the inner ring of the first clamping gear 21, the first clamping gear 21 meshes with the second clamping gear 211, the inner ring of the second clamping gear 211 is connected to the clamping gear support column 23, and the clamping gear support column 23... Mounted on the top of the micrometer upper plate 28, both the first clamping gear 21 and the second clamping gear 211 are equipped with drop clamping rods 20. The two drop clamping rods 20 are clamped and engaged with a drop compensation block 19. The drop compensation block 19 moves longitudinally with the two drop clamping rods 20, and its bottom engages with the top of the spring pendulum 15. Each drop clamping rod 20 includes a first rod 201, a diagonal rod 202, a second rod 203, and a connecting rod 204. The bottom of connecting rod 204 is connected to the top of the first clamping gear 21. The side of connecting rod 204 is connected to one end of the first rod 201. The other end of the first rod 201 is connected to one end of the inclined rod 202. The other end of the inclined rod 202 is connected to one end of the second rod 203. The second rod 203 is clamped to the falling body compensation block 19. The falling body compensation block 19 includes a falling cylinder 191 and a conical locking block 192. The bottom of the falling cylinder 191 is connected to the top of the conical locking block 192. The bottom of the conical block 192 is inserted into the V-shaped groove 153. A sliding surface 193 is provided on the outer side of the conical block 192. A clamping area 194 is formed between the sliding surface 193 and the falling cylinder 191. The second rod 203 is clamped to the clamping area 194. A clamping gear support 22 is provided on the top of the micrometer upper plate 28. The clamping gear motor 24 is located in the clamping gear support 22. The clamping gear support 22 is connected to the micrometer upper plate 28 by two clamping bolts 25.

[0103] In application: Scientific calculations show that the gravitational acceleration on the Earth's surface is about 6 times that on the lunar surface. Therefore, the gravitational anomaly on the lunar surface is much smaller than that on Earth. Without a fall compensation device, the spring of the lunar gravimeter developed on the ground would be extremely compressed due to the sharp decrease in mass after landing on the lunar surface, thus losing its measuring function and ultimately causing the instrument to fail and not play its important role. Therefore, this mechanism is essential and important. The sliding surface 193 of the second rod 203 and the fall compensation block 19 has a very high surface finish, which enables the clamping and releasing actions of the two second rods 203 to achieve the vertical upward and vertical downward movement of the fall compensation block 19. This accurately achieves the purpose of the fall compensation block 19 separating from and embedding into the V-shaped groove 153, and ultimately plays the role of increasing the mass of the second zero-length spring 142.

[0104] The above description is only a preferred embodiment of this application. The scope of protection of this application is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in this application should be included in the scope of protection recorded in the claims.

Claims

1. A lunar gravimeter sensor based on a zero-length metal spring, characterized in that: The lunar gravimeter sensor based on a zero-length metal spring includes a main frame (1), a zero-length metal spring (14), a spring suspension limiting mechanism (A), a spring capacitance micrometer mechanism (B), a spring pendulum locking mechanism (C), and a fall compensation weight-increasing mechanism (D). The spring suspension limiting mechanism (A) includes an upper spring support (11), an upper spring wire (12), a spring wire seat (13), a spring pendulum (15), and a permanent magnet (33); the upper spring support (11) is installed on the top of the inner wall of the main body frame (1), the bottom of the upper spring support (11) is connected to the top of the upper spring wire (12), the bottom of the upper spring wire (12) is connected to the top of the spring wire seat (13), the bottom of the spring wire seat (13) is connected to the top of the zero-length metal spring (14), and the zero-length metal spring (14) A spring support (27) is provided in the middle section. The bottom of the metal zero-length spring (14) is connected to the lower end of the spring pendulum (15). A feedback coil (32) is provided on the outer side of the bottom of the spring pendulum (15). The bottom of the spring pendulum (15) is engaged with the top of the permanent magnet (33). The bottom of the permanent magnet (33) is connected to the bottom of the inner wall of the main frame (1). The outer side of the lower end of the spring pendulum (15) is connected to one end of a plurality of limiting damping leaf springs (31). The other end of the limiting damping leaf springs (31) is connected to the inner side of the main frame (1). The spring capacitance micrometer mechanism (B) includes multiple suspension studs (2), a moving plate fixing ring (4), an upper micrometer fixing plate (28), a moving micrometer (29), and a lower micrometer fixing plate (30). The top of the multiple suspension studs (2) passes through the main body frame (1) and is connected by nuts. The bottom of the multiple suspension studs (2) passes through the upper micrometer fixing plate (28) and the lower micrometer fixing plate (30) in sequence and is connected by suspension nuts (6). The bottom of the moving plate fixing ring (4) is connected to the top of the spring pendulum (15). The top of the moving plate fixing ring (4) is bonded to the bottom of the moving micrometer (29). The moving micrometer (29) is set between the upper micrometer fixing plate (28) and the lower micrometer fixing plate (30). A zero-length metal spring (14) passes through the upper micrometer fixing plate (28), the moving micrometer (29), and the lower micrometer fixing plate (30) in sequence. The spring-loaded locking mechanism (C) includes a vertical stud (7), a locking motor (10), and a vertical gear (16). A clamping bracket (9) is installed at the bottom of the inner wall of the main body frame (1). The locking motor (10) is located inside the clamping bracket (9). The output shaft of the locking motor (10) is connected to the inner ring of the locking gear (8). The locking gear (8) meshes with the vertical gear (16). The internal thread of the vertical gear (16) engages with the external thread of the vertical stud (7). The vertical stud (7) is movably mounted on the vertical gear support (18). Above, the vertical gear support (18) is installed at the bottom of the inner wall of the main body frame (1). The top of the vertical gear support (18) is provided with a vertical gear pressure ring (17). The lower outer side of the vertical stud (7) is connected to the inner ring of the vertical gear pressure ring (17). The lower outer side of the vertical stud (7) is connected to the annular pressure claw (26). The annular pressure claw (26) is movably connected to the vertical gear support (18). The other end of the annular pressure claw (26) is in contact with the spring pendulum (15). The annular pressure claw (26) moves longitudinally with the vertical stud (7). The free fall compensation weight-increasing mechanism (D) includes a free fall compensation block (19), a free fall clamping rod (20), a first clamping gear (21), and a clamping gear motor (24); the bottom of the clamping gear motor (24) is connected to the top of the micrometer upper fixed plate (28), the output shaft of the clamping gear motor (24) is connected to the inner ring of the first clamping gear (21), the first clamping gear (21) meshes with the second clamping gear (211), and the inner ring of the second clamping gear (211) is connected to the inner ring of the first clamping gear (211). The clamping gear support (23) is connected and installed on the top of the micrometer upper plate (28). The top of the first clamping gear (21) and the second clamping gear (211) are both provided with a falling clamping rod (20). The two falling clamping rods (20) are clamped and cooperated with the falling compensation block (19). The falling compensation block (19) moves longitudinally with the two falling clamping rods (20). The bottom of the falling compensation block (19) is engaged with the top of the spring pendulum (15).

2. A lunar gravimeter sensor based on a zero-length metal spring according to claim 1, characterized in that: The metal zero-length spring (14) includes a first zero-length spring (141) and a second zero-length spring (142), which are connected by a spring support (27). The first zero-length spring (141) is made of a spring with a positive temperature coefficient, and the second zero-length spring (142) is made of a spring with a negative temperature coefficient. The absolute values ​​of the first zero-length spring (141) and the second zero-length spring (142) are equal. The stiffness, length, mean diameter and wire diameter of the first zero-length spring (141) and the second zero-length spring (142) are the same.

3. A lunar gravimeter sensor based on a zero-length metal spring according to claim 2, characterized in that: The spring support (27) includes an upper end plate (271), a lower end plate (272) and a plurality of triangular prisms (273). The bottom of the upper end plate (271) and the top of the lower end plate (272) are connected by a plurality of triangular prisms (273), and the plurality of triangular prisms (273) are arranged at equal intervals. The top of the upper end plate (271) is connected to the bottom of the first zero-length spring (141), and the bottom of the lower end plate (272) is connected to the top of the second zero-length spring (142).

4. A lunar gravimeter sensor based on a zero-length metal spring according to claim 1, characterized in that: The spring pendulum (15) includes a first mass (151), a connecting section (152) and a second mass (154). The bottom of the first mass (151) is connected to the top of the connecting section (152). A zero-length metal spring (14) is sleeved on the outer perimeter of the first mass (151). The bottom of the zero-length metal spring (14) is connected to the top of the connecting section (152), and the bottom of the connecting section (152) is connected to the top of the second mass (154). The outer perimeter of the connecting section (152) is connected to one end of a plurality of limiting damping leaf springs (31); The top of the second mass (154) contacts the annular pressure claw (26), and a slot (155) is provided at the bottom of the second mass (154). A permanent magnet (33) is embedded in the slot (155), and a feedback coil (32) is arranged around the outer side of the second mass (154). The top of the first mass body (151) is provided with a V-shaped groove (153), which is fitted with the falling body compensation block (19).

5. A lunar gravimeter sensor based on a zero-length metal spring according to claim 4, characterized in that: The falling body clamping rod (20) includes a first rod (201), a diagonal rod (202), a second rod (203), and a connecting rod (204). The bottom of the connecting rod (204) is connected to the top of the first clamping gear (21), the side of the connecting rod (204) is connected to one end of the first rod (201), the other end of the first rod (201) is connected to one end of the diagonal rod (202), the other end of the diagonal rod (202) is connected to one end of the second rod (203), and the second rod (203) is clamped to the falling body compensation block (19).

6. A lunar gravimeter sensor based on a zero-length metal spring according to claim 5, characterized in that: The free fall compensation block (19) includes a free fall cylinder (191) and a conical clamping block (192). The bottom of the free fall cylinder (191) is connected to the top of the conical clamping block (192). The bottom of the conical clamping block (192) is inserted into a V-shaped groove (153). A sliding surface (193) is provided on the outer side of the conical clamping block (192). A clamping area (194) is formed between the sliding surface (193) and the free fall cylinder (191). The second rod (203) is clamped to the clamping area (194).

7. A lunar gravimeter sensor based on a zero-length metal spring according to claim 6, characterized in that: The micrometer upper plate (28) is provided with a clamping gear support (22) on its top. The clamping gear motor (24) is located inside the clamping gear support (22). The clamping gear support (22) is connected to the micrometer upper plate (28) by two clamping bolts (25).

8. A lunar gravimeter sensor based on a zero-length metal spring according to claim 1, characterized in that: The outer side of the suspension stud (2) is fitted with a stud bushing (3); A micrometer upper fixing plate (28) and a micrometer lower fixing plate (30) are provided with a fixing plate bushing (5), which is sleeved on the outside of the suspension stud (2).

9. A lunar gravimeter sensor based on a zero-length metal spring according to claim 1, characterized in that: The vertical stud (7) includes an upper threaded stud (71) and a lower cylinder (72). The upper threaded stud (71) is threaded with the internal thread of the vertical gear (16), and the lower cylinder (72) is slidably engaged with the vertical gear support (18). The side of the lower cylinder (72) is connected to one end of the annular pressure claw (26).

10. A lunar gravimeter sensor based on a zero-length metal spring according to claim 9, characterized in that: The vertical gear support (18) includes a hollowed-out lower support (181), a movable ring (182) and a connecting column (183). The top of the lower support (181) is connected to the bottom of the movable ring (182) through the connecting column (183), and the lower end cylinder (72) is movably connected to the movable ring (182) and the lower support (181) in sequence. The annular pressure claw (26) is disposed between the lower support (181) and the movable ring (182); The vertical gear pressure ring (17) is installed on the top of the lower support (181), and the inner ring of the vertical gear pressure ring (17) is connected to the lower end cylinder (72).

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