An electromagnetic spring lunar soil penetrator with pressure sensing function and its control method

Abstract

An electromagnetic spring lunar soil penetrator with pressure sensing function includes a power module, a penetration module, and a control module. The power module includes a lower housing and an upper housing. A first electromagnet and a second electromagnet are fixed to the lower end of the lower housing and the upper end of the upper housing, respectively. An impact hammer is slidably connected between the first guide rail and the second guide rail. The penetration module includes a storage roller and a thin housing. The control module includes a PLC controller, a displacement sensor, and a pressure sensor. The PLC controller receives angle and pressure signals and controls the motor to adjust the release length of the thin housing. The PLC controller drives the permanent magnet to move the impact hammer up and down by controlling the magnitude and direction of the current in the first and second coils. The impact hammer impacts the clamp and drives the thin housing to penetrate the lunar soil. The lunar soil penetrator control method drives the thin housing to penetrate the lunar soil by controlling the magnitude and direction of the electromagnetic force. Compared with the traditional energy storage spring structure, this lunar soil penetrator can improve the penetration accuracy, significantly improve the hysteresis phenomenon, and has an adaptive adjustment function.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerospace, and particularly relates to an electromagnetic spring lunar soil penetrator with pressure sensing function and a control method thereof. BACKGROUND

[0002] In modern space exploration missions, the moon, as a satellite of the Earth, has unique and important scientific research value. The lunar soil (also known as lunar surface soil) on the moon's surface contains rich scientific information, such as the formation and evolution history of the moon, the evolution process of the solar system, etc. By analyzing the lunar soil samples, scientists can obtain important data about the composition, structure and historical evolution of the lunar surface material, thereby deepening the understanding of the moon and the entire solar system.

[0003] The lunar soil penetrator is a device specially used for lunar soil exploration, which mainly functions to penetrate the lunar soil through a thin shell structure to achieve the collection and analysis of lunar soil samples at different depths. Traditional lunar soil penetrators usually rely on mechanical energy storage springs to provide the required kinetic energy to achieve the penetration action. However, this mechanical energy storage structure has significant drawbacks. First, the use of mechanical springs can cause significant hysteresis, which refers to the inability of the spring to immediately respond to external control signals due to internal friction and deformation during energy storage and release, and can cause uneven energy release (such as the spring being stuck and unable to release). The unevenness of energy release directly affects the sampling accuracy of the penetrator, and thus the accuracy of scientific analysis. Second, the energy storage capacity of mechanical springs is fixed and cannot be dynamically adjusted according to actual needs, which limits the possibility of flexible energy output adjustment under different load conditions. Mechanical springs are prone to fatigue and wear after long-term use, which can cause the performance of the spring to gradually decline, affecting the reliability and service life of the system. In long-term lunar exploration missions, this reliability problem is particularly significant, as the lunar soil penetrator needs to work stably in a complex and variable lunar environment for a long time. In addition, traditional lunar soil penetrators do not have the function of measuring the penetration resistance of the thin shell, and cannot timely feedback the physical structure and stratigraphic structure of the lunar soil through the penetration resistance, affecting the subsequent adjustment of the penetration depth.

[0004] In order to overcome these defects, researchers have conducted research from different aspects such as the material properties and structural design of the spring, but the results are not satisfactory. The size and weight of the penetrator cannot be guaranteed. Therefore, it is a current research hotspot and a technical bottleneck that needs to be solved urgently to develop a lunar soil penetrator that uses a new type of energy storage element, has small size, light weight, low system hysteresis and high reliability.

[0005] A study on the mechanical properties of impact penetration of a lunar soil profile flexible probe in a paper titled "Research on the Mechanical Properties of Impact Penetration of Lunar Soil Profile Flexible Probe" (Wang Hao, Harbin Institute of Technology, 2020) studies a new type of flexible probe as a penetration device. The device realizes low disturbance in-situ detection of lunar soil profile through flexible probe; however, the adaptability of this study to different particle sizes and compactness in complex lunar soil environment still has deficiencies, especially the best balance between penetration efficiency and device stability has not been found.

[0006] The invention with patent publication number "CN 109306691 A" and title "Self-adjusting visual precise dynamic sounding device" discloses a device that uses an adjustable operating table combined with an internal electromagnet and permanent magnet to dynamically probe soil. By controlling the drop hammer with electromagnetic force, it realizes high-precision and adaptable detection of various terrains, solving the problems of large manual operation error and high labor intensity; however, when facing extremely soft or hard soil, the electromagnetic force may not be sufficient to provide effective penetration power.

[0007] The invention with patent publication number "CN 114483022 A" and title "Recyclable continuous hammering device based on electromagnetic coil gun" discloses a device that drives hammering through an electromagnetic coil. It uses continuous hammering method and shows excellent performance in seabed geological survey, especially in adapting to gravel layer or hard stratum; but the hammering energy and frequency of this device are difficult to accurately control, limiting its flexible application in complex geological conditions. SUMMARY

[0008] To overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to propose an electromagnetic spring lunar soil penetrator with pressure sensing function and its control method, wherein the lunar soil penetrator uses an electromagnetic spring as an energy storage mechanism, accurately controls the size and direction of the coil current through the controller, forms a variable direction and size electromagnetic force instead of traditional mechanical force, realizes accurate control and release of energy, significantly improves the hysteresis of traditional penetrators, and greatly improves the operation precision and efficiency; by setting a pressure sensor at the tip of the thin shell, the penetration resistance is measured and recorded, and the power size of the subsequent penetrator is further set by the controller; the lunar soil penetrator in the present invention solves the problems of high hysteresis and low reliability caused by the use of mechanical spring energy storage in existing penetrators, as well as the small range of mechanical spring stored potential energy, and the inability of existing penetrators to directly measure penetration resistance, which affects the study of lunar soil layering structure.

[0009] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0010] An electromagnetic spring moon soil penetrator with pressure sensing function, comprising a power module, a penetration module and a control module: the power module converts electric energy into kinetic energy of the impact hammer 9 by using electromagnetic spring, the penetration module drives the thin shell 19 to penetrate into the moon soil by using the kinetic energy of the impact hammer 9, and the control module adjusts the size of the output electric energy of the power module in the next step by using the sensor to sense the penetration depth and resistance of the thin shell 19 in the last step.

[0011] Further, the power module comprises a U-shaped lower shell 1, a first electromagnet is fixed on the inner surface of the lower end of the lower shell 1, the first electromagnet comprises a first ferromagnetic body 2 and a first coil 3 wound around the surface of the first ferromagnetic body 2, an inverted U-shaped upper shell 4 is installed on the upper part of the lower shell 1, a second electromagnet is fixed on the inner surface of the upper end of the upper shell 4, the second electromagnet comprises a second ferromagnetic body 5 and a second coil 6 wound around the surface of the second ferromagnetic body 5, the first guide rail 7 and the second guide rail 8 are fixed on the inner side of the upper shell 4 and / or the inner side of the lower shell 1 symmetrically along the axis direction of the upper shell 4, the first guide rail 7 and the second guide rail 8 are located between the first electromagnet and the second electromagnet, the impact hammer 9 is connected between the first guide rail 7 and the second guide rail 8, the permanent magnet 10 is fixed on the impact hammer 9, the lower end of the impact hammer 9 is an inverted v-shaped inclined surface structure 901, the power module further comprises a gripper between the impact hammer 9 and the first electromagnet, the gripper comprises a first clamping block 11 and a second clamping block 12, the lower part of the first clamping block 11 is connected with one end of the first return spring 13, the lower part of the second clamping block 12 is connected with one end of the second return spring 14, the other end of the first return spring 13 and the other end of the second return spring 14 are respectively connected with the inner surface of the lower end of the lower shell 1, when the impact hammer 9 collides with the gripper during the downward sliding process along the first guide rail 7 and the second guide rail 8, the inclined surface structure 901 makes the first clamping block 11 and the second clamping block 12 close to each other, the upper shell 4, the first ferromagnetic body 2, the impact hammer 9, the permanent magnet 10, the gripper, the second ferromagnetic body 5 and the lower shell 1 are all provided with a first hole along the axis direction of the upper shell 4.

[0012] Further, the penetration module comprises a storage roller 16, the storage roller 16 is fixed on the upper part of the upper shell 4, the thin shell 19 is wound on the storage roller 16, the storage roller 16 is connected with the power output shaft of the motor 17, the thin shell 19 can be released by the motor 17, and the thin shell 19 can pass through the first hole and extend to the lower part of the lower shell 1 by the action of the power module and the control module.

[0013] Further, the control module comprises a PLC controller 20, a displacement sensor 21 and a pressure sensor 22, the PLC controller 20 is electrically connected with the first coil 3, the second coil 6, the motor 17, the displacement sensor 21 and the pressure sensor 22 respectively, the PLC controller 20 comprises an H-bridge circuit submodule and a pulse width modulation (PWM) driving submodule, the displacement sensor 21 is coaxially installed with the storage roller 16, the displacement sensor 21 detects the angle of rotation of the storage roller 16 and transmits the angle signal to the PLC controller 20, the pressure sensor 22 is installed at the top end of the thin shell 19, the pressure sensor 22 detects the penetration resistance of the thin shell 19 when penetrating the lunar soil and transmits the pressure signal to the PLC controller 20, the PLC controller 20 receives the angle signal and the pressure signal, analyzes and determines the target length of the next release of the thin shell 19 through the internal program, and then outputs the motor 17 current signal to the motor 17 for controlling the motor 17 to drive the storage roller 16 to rotate to release the target length of the thin shell 19 in advance, the PLC controller 20 outputs the first coil 3 current signal and the second coil 6 current signal to the H-bridge circuit submodule and the PWM driving submodule according to the target length, the target power and the stress direction of the permanent magnet 10, and the H-bridge circuit submodule and the PWM driving submodule receive the first coil 3 current signal and the second coil 6 current signal to control the current size and direction of the first coil 3 and the second coil 6.

[0014] Further, the first clamping block 11 and the second clamping block 12 are symmetrically distributed along the axis direction of the upper shell 4, and the outer side of the first clamping block 11 and the second clamping block 12 away from the axis of the upper shell 4 is a curved surface structure.

[0015] Further, the slope structure 901 at the lower end of the impact hammer 9 is symmetrically distributed along the axis direction of the upper shell 4, and the diameter of the inverted V-shaped opening is greater than the vertical projection diameter of the first clamping block 11 and the second clamping block 12.

[0016] Further, the power module further comprises a retainer 15, the retainer 15 is an inverted V-shaped opening and is located below the clamp, the lower end of the retainer 15 passes through the first hole and is fixed on the lower shell 1, and the clamp is located inside the retainer 15 when moving downward.

[0017] Further, the first ferromagnet 2 and the second ferromagnet 5 are both annular ferromagnets, and the permanent magnet 10 is an annular permanent magnet.

[0018] Further, the compressible length of the first return spring 13 and the second return spring 14 is not less than 5% of the distance between the first electromagnet and the second electromagnet.

[0019] The application further discloses a control method of the electromagnetic spring lunar soil penetrator with the pressure sensing function.

[0020] S1, the PLC controller 20 in the control module controls the current direction and current size of the first coil 3 and the second coil 6, so that the first electromagnet generates a first magnetic field opposite to the magnetic field direction of the permanent magnet 10, and the second electromagnet generates a second magnetic field same as the magnetic field direction of the permanent magnet 10, and the first magnetic field and the second magnetic field jointly act on the permanent magnet 10 and the impact hammer 9 to lift the permanent magnet 10 and the impact hammer 9 along the first guide rail 7 and the second guide rail 8 to the end of the second electromagnet;

[0021] S2, the control module controls the motor 17 to drive the storage roller 16 to rotate, so that the thin shell body 19 is released to a target length;

[0022] S3, the control module changes the current direction of the first coil 3 and the second coil 6 in step S1, so that the permanent magnet 10 is subjected to an electromagnetic force towards the direction of the first electromagnet, and the permanent magnet 10 drives the impact hammer 9 to move along the first guide rail 7 and the second guide rail 8 towards the direction of the first electromagnet; when the impact hammer 9 moves to collide with the gripper, the first clamping block 11 and the second clamping block 12 drive the thin shell body 19 to move downward at the same time of clamping the thin shell body 19 in step S2, so that the thin shell body 19 penetrates into the lunar soil, and the gripper moves downward at the same time of compressing the first return spring 13 and the second return spring 14;

[0023] S4, the step S1 is repeated, wherein the PLC controller 20 receives the angle signal sent by the displacement sensor 21 and the pressure signal sent by the pressure sensor 22, analyzes the penetration depth of the thin shell body 19 in step S3, and adjusts the current direction and current size of the first coil 3 and the second coil 6 in step S1;

[0024] S5, steps S2 to S4 are repeated until the penetration depth of the thin shell body 19 analyzed by the PLC controller 20 in step S4 is a target depth.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] 1. The present application detects the angle of rotation of the storage roller 16 in real time through the displacement sensor 21 in the control module, and the PLC controller 20 accurately controls the release length of the thin shell 19 of the penetration module according to the next target penetration length after receiving the angle signal and analyzing the penetration depth of the thin shell 19, and the PLC controller 20 can accurately control the current size and direction of the first coil 3 and the second coil 6 in the power module, so that the permanent magnet 10 drives the impact hammer 9 to move according to the target penetration power, and the current size is flexibly and accurately adjusted to adjust the impact force in the process, so that the penetration depth and sampling process of the thin shell 19 are more controllable according to the lunar soil condition of different compactness, not only reduces the detection error caused by excessive or insufficient impact, improves the collection accuracy of scientific data, but also avoids the damage of excessive impact force to the device and the lunar soil, improves the applicability of the penetrator in various environments, improves the reliability and service life of the penetrator, and optimizes the accurate control of the release of electric energy, greatly improves the energy use efficiency and working efficiency of the penetrator.

[0027] 2. The present application can make the kinetic energy of the impact hammer 9 directly transmitted to the holder through the inclined surface structure 901 of the impact hammer 9 and the curved surface structure design of the holder, realize efficient use of impact force, and the curved surface structure of the holder decomposes the impact force of the impact hammer 9 into longitudinal penetration force and transverse clamping force, ensures that the penetration process is stable and effective; the structure design of the impact hammer 9 and the holder can adapt to lunar soil of different density and hardness, and avoid clamping or penetration failure caused by lunar soil unevenness; the clamping surface of the holder is reasonably designed, the flexible lining or protective coating of the holder is increased, damage to the thin shell 19 is avoided, and the service life and penetration quality of the thin shell 19 are improved.

[0028] 3. The present application adopts a thin shell 19 with a C-shaped structure section as the penetration main body, and the inside of the thin shell 19 is a C-shaped cavity, which can be coiled and folded in the spacecraft before penetrating into the lunar soil, and the storage size and weight are more advantageous than the rigid penetration body, the launch and transportation cost is lower, and the economy is better, and the penetration stiffness can also be guaranteed not to deviate, and the reliability during work is greatly improved when the probe penetrates and encounters underground obstacles.

[0029] 4. The present application can directly measure the penetration resistance and other key parameters in the penetration process by arranging a pressure sensor at the top end of the penetrator, and provide direct basis for accurately quantifying the key physical parameters of the lunar soil such as cohesion, internal friction angle and porosity, and help to deeply analyze the interaction mechanism between lunar soil particles; at the same time, with the help of the penetration resistance at different penetration depths, it can also help the lunar soil layering structure research, assist in defining the interface of different lunar soil layers, and study the vertical distribution of physical properties such as lunar soil layering thickness, hardness and mechanical properties, and provide help for lunar geological evolution modeling.

[0030] Compared with the traditional energy storage spring structure, the lunar soil penetrator can improve the penetration accuracy, significantly improve the hysteresis phenomenon, and has the self-adaptive adjustment function, further improves the adaptability, reliability and service life of the equipment, and is very suitable for long time and complex environment of space task, and provides strong support for the lunar soil penetration and detection technology in future lunar exploration mission. BRIEF DESCRIPTION OF DRAWINGS

[0031] Fig. 1 It is an axial section schematic view of the lunar soil penetrator of the application.

[0032] Fig. 2 It is a schematic view of the electromagnetic spring part structure of the application.

[0033] Fig. 3 It is a schematic view of the transverse section structure of the thin shell body of the application.

[0034] In the figure, 1 is a lower shell, 2 is a first ferromagnetic body, 3 is a first coil, 4 is an upper shell, 5 is a second ferromagnetic body, 6 is a second coil, 7 is a first guide rail, 8 is a second guide rail, 9 is an impact hammer, 901 is an inclined surface structure, 10 is a permanent magnet, 11 is a first clamping block, 12 is a second clamping block, 13 is a first return spring, 14 is a second return spring, 15 is a retainer, 16 is a storage roller, 17 is a motor, 18 is a bracket, 19 is a thin shell body, 20 is a PLC controller, 21 is a displacement sensor, and 22 is a pressure sensor. DETAILED DESCRIPTION

[0035] The application provides an electromagnetic spring lunar soil penetrator with pressure sensing function and a control method thereof, aiming at solving the problems of high hysteresis and low reliability of the existing mechanical spring energy storage system, by adopting an electromagnetic spring as a core energy storage mechanism, and combining the one-step penetration depth and penetration resistance parameters of the penetrator to realize the accurate control of the current size and current direction of the next step, the application realizes efficient release of energy and real-time feedback adjustment of the sensor.

[0036] The application will be further described below Figs. 1 to 3 Further detailed description of the application:

[0037] In the first aspect, the electromagnetic spring lunar soil penetrator with pressure sensing function comprises a power module, a penetration module and a control module: the power module converts electric energy into kinetic energy of the impact hammer 9 by using an electromagnetic spring, the penetration module drives the thin shell body 19 to penetrate into lunar soil by using the kinetic energy of the impact hammer 9, and the control module adjusts the size of the output electric energy of the power module in the next step by using sensors to sense the one-step penetration depth and lunar soil resistance of the thin shell body 19.

[0038] As Fig. 1 and Fig. 2As shown, the power module comprises a U-shaped lower housing 1, a first electromagnet is fixed on the inner surface of the lower end of the lower housing 1, the first electromagnet can be fixed by clamps or other fixing methods, the first electromagnet comprises a first ferromagnetic body 2 and a first coil 3 wound around the surface of the first ferromagnetic body 2, a reverse U-shaped upper housing 4 is installed on the upper part of the lower housing 1, a second electromagnet is fixed on the inner surface of the upper end of the upper housing 4, the first electromagnet and the second electromagnet can be fixed by clamps or other fixing methods, the second electromagnet comprises a second ferromagnetic body 5 and a second coil 6 wound around the surface of the second ferromagnetic body 5, the first guide rail 7 and the second guide rail 8 are fixed symmetrically along the axis direction of the upper housing 4 on the inner side of the upper housing 4 and / or the inner side of the lower housing 1, the first guide rail 7 and the second guide rail 8 are located between the first electromagnet and the second electromagnet, the impact hammer 9 is connected slidingly between the first guide rail 7 and the second guide rail 8, the permanent magnet 10 is fixed and connected on the impact hammer 9 by bolts, buckles, inlaying and other mechanical methods; when a certain current passes through the first coil 3 or the second coil 6, a magnetic field of a certain direction is formed on the first electromagnet or the second electromagnet, when the direction of the current changes, the direction of the magnetic field changes accordingly, by setting the current of the first coil 3 and the second coil 6 respectively, the first coil 3 or the second coil 6 is the same as or opposite to the self-magnetic field of the permanent magnet 10, an electromagnetic force is generated to attract or repel the permanent magnet 10 upward or downward, so that the permanent magnet 10 drives the impact hammer 9 to slide upward or downward along the first guide rail 7 and the second guide rail 8; the lower end of the impact hammer 9 is a slope structure 901 with a reverse v-shaped opening, the power module further comprises a holder located between the impact hammer 9 and the first electromagnet, the holder comprises a first clamping block 11 and a second clamping block 12, the lower part of the first clamping block 11 is connected with one end of the first return spring 13, the lower part of the second clamping block 12 is connected with one end of the second return spring 14, the other end of the first return spring 13 and the other end of the second return spring 14 are respectively connected with the inner surface of the lower end of the lower housing 1, the first return spring 13 and the second return spring 14 can drive the holder to return to the original position after the force is removed, when the impact hammer 9 collides with the holder during the downward sliding process along the first guide rail 7 and the second guide rail 8, the slope structure 901 can apply an external force to the first clamping block 11 and the second clamping block 12 respectively along the axis direction of the upper housing 4, so that the first clamping block 11 and the second clamping block 12 approach each other, the upper housing 4, the first ferromagnetic body 2, the impact hammer 9, the permanent magnet 10, the holder, the second ferromagnetic body 5 and the lower housing 1 are all provided with a first hole along the axis direction of the upper housing 4.

[0039] The electromagnetic spring comprises a first electromagnet, a second electromagnet, a permanent magnet 10, an impact hammer 9, a first guide rail 7 and a second guide rail 8 in the power module, and the first electromagnet and the second electromagnet form electromagnetic force to drive the permanent magnet to move up and down along the first guide rail 7 and the second guide rail 8 when the first coil 3 and the second coil 6 are powered on. The electromagnetic spring design has high controllability, overcomes the hysteresis phenomenon of the traditional mechanical spring in the energy release process, significantly improves the response speed and working precision of the lunar soil penetrator, and avoids mechanical friction, greatly improves the reliability and durability of the system, and is particularly suitable for complex and variable extraterrestrial environments such as the moon. The automatic coordination capability of the lunar soil penetrator ensures efficient operation under different lunar soil conditions, significantly enhances adaptability and stability, and the application of the electromagnetic spring reduces the maintenance requirements of the lunar soil penetrator, making it more suitable for long-term space missions.

[0040] The working principle of the whole power module includes an energy storage stage and an energy release stage: in the energy storage stage, the control module adjusts the magnetic field of the first electromagnet and the second electromagnet, so that the impact hammer 9 and the connected permanent magnet 10 are gradually lifted to a predetermined height, and the stored energy is gradually accumulated to ensure the effectiveness of the subsequent energy release stage; in the energy release stage, the control module reverses the magnetic field direction of the first electromagnet and the second electromagnet, rapidly pushes the impact hammer 9 to accelerate downward, converts the stored elastic potential energy into kinetic energy, and the thin shell 19 in the penetration module obtains powerful power to realize rapid and accurate penetration of the lunar soil.

[0041] The innovative design of the power module is to use an electromagnetic spring as an energy storage device, which breaks through the hysteresis phenomenon of the traditional mechanical spring system and significantly improves the response speed, efficiency and reliability of the system.

[0042] The penetration module comprises a storage roller 16, the storage roller 16 can be fixed on the upper part of the upper shell 4 through a support 18, the thin shell 19 is curled and wound on the storage roller 16, and the storage roller 16 is connected with the power output shaft of the motor 17. The storage roller 16 can release the thin shell 19 through the motor 17, and the thin shell 19 passes through the first hole and extends to the lower part of the lower shell 1 under the action of the power module and the control module; in the non-working state, the thin shell 19 is curled and stored on the storage roller 16, before the penetration operation, the motor 17 controls the storage roller 16 to rotate in advance to release the thin shell 19 of the target length, and when the penetration operation is performed, the clamp clamps and drives the thin shell 19 to move downward by using the kinetic energy of the impact hammer 9, so as to complete the penetration of the thin shell 19 of the target length into the lunar soil.

[0043] The storage roller 16 is responsible for storing the thin shell 19 in the non-working state and gradually releasing the thin shell 19 during the penetration operation; the release mechanism of the storage roller 16 combined with the PLC controller 20 is accurate, ensuring that the released thin shell 19 has just the right length and does not affect the penetration efficiency due to being too short or too long. The flexible design of the storage roller 16 makes the penetration module adaptable and able to adjust the release strategy according to different lunar soil conditions, ensuring smooth operation of the penetration process.

[0044] The core function of the penetration module is to drive the thin shell 19 into the lunar soil through the power module, thereby completing the collection and detection of the lunar soil sample. At the beginning of the penetration operation, the control module first releases the thin shell 19 of the target length through the storage roller 16 to prepare for the subsequent penetration action. As the kinetic energy of the impact hammer 9 is transmitted to the gripper, the gripper drives the thin shell 19 to start penetrating the lunar soil. During the penetration process, the impact force is reasonably decomposed to ensure accurate transmission of the penetration force. Through this precise mechanical design, the penetration module can avoid applying excessive pressure to the thin shell 19, thereby achieving precise penetration in complex lunar soil conditions.

[0045] The overall design of the penetration module fully considers the complexity and variability of the lunar environment, and achieves efficient and accurate penetration operation through the coordinated work of various components. The C-shaped structure design of the thin shell 19, the precise release of the storage roller 16, and the mechanical optimization of the gripper collectively ensure the efficient operation of the system. The penetration module not only improves the working efficiency of the equipment, but also enhances the adaptability and reliability of the system through mechanical distribution and material optimization, ensuring its continuous and stable operation in long-term space missions and meeting the requirements of complex exploration tasks.

[0046] The purpose of the control module is to achieve efficient and stable operation during lunar soil penetration through precise control of the power module and the penetration module. The PLC controller 20 can dynamically adjust the current size and direction of the first electromagnet and the second electromagnet in the next step through the internal program of the PLC controller 20 based on the angle of the previous step of the storage roller 16 feedback by the displacement sensor 21 and the pressure signal feedback by the pressure sensor 22, ensuring that the power module outputs appropriate penetration force. This adaptability significantly enhances the efficient working efficiency of the lunar soil penetrator in complex task environments, enabling it to efficiently complete exploration tasks under different lunar soil density and hardness conditions.

[0047] The control module comprises a PLC controller 20, a displacement sensor 21 and a pressure sensor 22, the PLC controller 20 is electrically connected with the first coil 3, the second coil 6, the motor 17, the displacement sensor 21 and the pressure sensor 22 respectively, the PLC controller 20 comprises an H-bridge circuit sub-module and a PWM drive sub-module, the displacement sensor 21 is coaxially installed with the storage roller 16 and located on one side of the storage roller 16, before the thin shell 19 is released, the first coil 3 and the second coil 6 are not electrified, the permanent magnet 10 is only subjected to the action of gravity to make the impact hammer 9 contact the clamp; the displacement sensor 21 detects the angle of rotation of the storage roller 16 and transmits the angle signal to the PLC controller 20, the pressure sensor 22 is installed at the top end of the thin shell 19, and the pressure sensor 22 detects the penetration resistance when the thin shell 19 penetrates into the lunar soil and transmits the pressure signal to the PLC controller 20.

[0048] The pressure sensor 22 used in the application is a flexible thin film pressure sensor, specifically a resistance type or a capacitance type flexible thin film pressure sensor, the resistance type flexible thin film pressure sensor is usually composed of a flexible substrate material (such as polydimethylsiloxane) and a conductive material (such as a carbon nanotube, a metal nanowire, a conductive polymer and the like), the conductive material is distributed on the substrate, when subjected to pressure, the conductive material will deform or change the contact state, thereby causing the resistance of the conductive path to change; the capacitance type flexible thin film pressure sensor is mainly composed of two flexible conductive electrodes and a dielectric layer sandwiched therebetween, the flexible electrode material can be a metal film (such as a gold film, a silver film), a conductive polymer and the like, and the dielectric layer is usually a material with good elasticity (such as silicone rubber, polyimide and the like), when subjected to pressure, the thickness or the dielectric constant of the dielectric layer will change, thereby changing the capacitance value.

[0049] After receiving the angle signal and the pressure signal, the PLC controller 20 analyzes the extension amount of the thin shell 19 through an internal program and determines the target length of the next release of the thin shell 19, and then outputs a motor 17 current signal to the motor 17 for controlling the motor 17 to drive the storage roller 16 to rotate to release the target length and target power of the thin shell 19 in advance, the PLC controller 20 is electrically connected with the first coil 3 and the second coil 6 through the H-bridge circuit sub-module and the PWM drive sub-module and a relay, the use of the relay can provide electrical isolation and prevent high current from damaging the PLC controller 20.

[0050] The PLC controller 20 outputs a first group of first coil 3 current signal and second coil 6 current signal (including current direction and current size) to the H-bridge circuit submodule and PWM drive submodule according to the target length, target power and the force direction of the permanent magnet 10, and the H-bridge circuit submodule and PWM drive submodule control the current size and direction of the first coil 3 and the second coil 6 after receiving the first coil 3 current signal and the second coil 6 current signal. The PLC controller 20 can change the current direction of the first coil 3 current and the second coil 6 current through the H-bridge circuit submodule, and can change the current size of the first coil 3 current and the second coil 6 current through the PWM drive submodule. The released first coil 3 current makes the first electromagnet form a magnetic field opposite to the permanent magnet, and the second coil 6 current makes the second electromagnet form a magnetic field same as the permanent magnet. The permanent magnet 10 is driven by the upward repulsive force of the first electromagnet and the upward attractive force of the second electromagnet to slide the impact hammer 9 upward, and the potential energy of the permanent magnet 10 is stored. When the thin shell 19 needs to be released, the PLC controller 20 outputs the next group of first coil 3 current signal and second coil 6 current signal to the H-bridge circuit submodule and PWM drive submodule, and finally makes the current of the first coil 3 and the second coil 6 opposite to the current direction of the first group, so that the permanent magnet 10 is driven by the downward attractive force of the first electromagnet and the downward repulsive force of the second electromagnet to slide the impact hammer 9 downward to impact the gripper, the gripper clamps the thin shell 19 and drives the thin shell 19 to move downward, and the thin shell 19 penetrates into the lunar soil.

[0051] After the thin shell 19 penetrates into the lunar soil, the displacement sensor 21 detects the angle of rotation of the storage roller 16 and feeds back the angle signal to the PLC controller 20, and the PLC controller 20 analyzes the angle signal and adjusts the target length of the next release of the thin shell 19.

[0052] The system is composed of a power module, a penetration module and a control module, and the specific working principle is as follows: the control module as the core coordination unit receives the angle signal of the rotation of the storage roller 16, i.e. the displacement data of the thin shell 19, and the pressure signal fed back by the pressure sensor 22 through the PLC controller 20, and calculates the target length of the next extension of the thin shell 19, i.e. the target penetration lunar soil depth and the target power size in real time, the PLC controller 20 adjusts the target length released by the thin shell 19 in the penetration module in advance through the control of the motor 17, and then the PLC controller 20 outputs the first coil 3 current signal and the second coil 6 current signal to the H-bridge circuit submodule and the PWM drive submodule, and the H-bridge circuit submodule and the PWM drive submodule control and adjust the current direction and size of the first coil 3 and the second coil 6 after receiving the corresponding signals, so that the permanent magnet 10 is subjected to upward or downward electromagnetic force, realizing the energy storage and impact action of the impact hammer 9 fixedly connected with the permanent magnet 10 in the power module; the power module controls the current of the first coil 3 and the second coil 6 through the control module, realizes the electromagnetic force interaction between the first electromagnet and the second electromagnet and the permanent magnet 10, drives the impact hammer 9 to slide up and down along the first guide rail 7 and the second guide rail 8 by the permanent magnet 10, and the kinetic energy of the impact hammer 9 moving downward is transmitted to the gripper, and the first clamping block 11 and the second clamping block 12 clamp and push the thin shell 19 of the penetration module to penetrate into the lunar soil; the displacement sensor 21 detects the penetration depth of the thin shell 19 and feeds back to the PLC controller 20, and the pressure sensor 22 detects the penetration resistance when the thin shell 19 penetrates into the lunar soil and transmits the pressure signal to the PLC controller 20, and the PLC controller 20 receives the above signals and adjusts the magnetic field direction and magnetic field size of the first electromagnet and the second electromagnet by using the internal program to realize the energy storage and impact action of the next impact hammer 9, and the motor 17 drives the storage roller 16 to rotate according to the motor 17 current signal of the control module and releases the target length of the next release of the thin shell 19 in advance, ensuring that the penetration depth meets the task requirements.

[0053] The modules work together and closely cooperate to realize the precise penetration operation of the thin shell 19, the power module provides the impact force required for penetration, the penetration module completes the storage and release of the thin shell 19, and the control module ensures efficient and accurate operation of the system through real-time feedback and adjustment, and finally realizes the multiple penetration of the thin shell 19 and meets the target depth.

[0054] Further, the first clamping block 11 and the second clamping block 12 are symmetrically distributed along the axis direction of the upper shell 4, and the outer side of the first clamping block 11 and the second clamping block 12 away from the axis of the upper shell 4 is a curved surface structure. When the inclined surface structure 901 of the impact hammer 9 moves downward to collide with the curved surface structure, the smooth curved surface structure can decompose the impact force of the impact hammer 9 into a downward penetrating force parallel to the axis direction of the upper shell 4 (i.e. vertically downward) and a clamping force perpendicular to the axis direction of the upper shell 4 and pointing to the axis of the upper shell 4 (i.e. horizontally inward), ensuring the stable penetration of the thin shell 19.

[0055] The gripper drives the thin shell 19 to move downward by the kinetic energy of the impact hammer 9, and reasonably decomposes the impact force during penetration, ensuring that the thin shell 19 maintains a stable movement direction during penetration, avoiding deviation caused by lunar soil resistance. The gripper is made of high-strength metal material (such as alloy steel or titanium alloy) to ensure that the gripper can withstand the high-frequency impact and load of the impact hammer 9. The surface of the gripper is treated by hardening or coated with a wear-resistant layer and other protective coatings to prolong the service life. The part of the first clamping block 11, the second clamping block 12 and the thin shell 19 in contact with the convex or concave surface of the thin shell 19 is matched. The part of the first clamping block 11, the second clamping block 12 and the thin shell 19 in contact also includes an anti-skid design (such as a textured or increased friction coating) to prevent the thin shell 19 from sliding or deviating during penetration, improving the penetration accuracy and reliability of the system.

[0056] Further, the inclined surface structure 901 at the lower end of the impact hammer 9 is symmetrically distributed along the axis direction of the upper shell 4, and the diameter of the inverted v-shaped opening is greater than the vertical projection diameter of the first clamping block 11 and the second clamping block 12. The main body of the impact hammer 9 is made of high-strength metal material (such as steel or titanium alloy) to ensure that it has sufficient strength and wear resistance, and can maintain stable performance under long-term impact. The annular permanent magnet 10 is mechanically fixed and installed on the impact hammer 9 by bolts, buckles or inlaying, etc. The center of the annular permanent magnet 10 coincides with the center of the impact hammer 9, ensuring that the force of the permanent magnet 10 and the first electromagnet and the second electromagnet is evenly distributed, and ensuring that the impact hammer 9 moves smoothly along the first guide rail 7 and the second guide rail 8. Rolling elements (such as balls or rollers) are placed between the first guide rail 7 and the second guide rail 8 on both sides of the impact hammer 9 to reduce friction and avoid cold welding caused by sliding friction, increasing reliability.

[0057] Further, as shown in FIG. 6, the first guide rail 7 and the second guide rail 8 are symmetrically arranged on both sides of the impact hammer 9, and the first guide rail 7 and the second guide rail 8 are arranged in the same direction, and the first guide rail 7 and the second guide rail 8 are arranged in the same direction. Fig. 3As shown, the thin shell 19 is in a C-shaped structure, and the inside of the thin shell 19 is a C-shaped cavity. The thin shell 19 is made of high-strength and light-weight materials (such as titanium alloy, composite material or polymer), which can withstand impact force and lunar soil friction during penetration and maintain a certain flexibility to adapt to non-uniform strata. The flexible thin film pressure sensor is installed on the side of the top end of the thin shell 19. The flexible conformal attachment and ultra-thin thickness of the flexible thin film pressure sensor ensure that the pressure sensor does not affect the thin shell penetration into the lunar soil operation, and at the same time can directly detect the penetration resistance. The inside of the thin shell 19 is a C-shaped cavity structure, the outer wall of the thin shell 19 is thin and has a certain bending ability, which can adapt to different density and hardness areas inside the lunar soil. The top end of the thin shell 19 is designed as a conical or hemispherical sharp tip to reduce the penetration resistance. The special shape and material of the thin shell 19 can be stored in a high-density form in the space vehicle in a curled form, occupying a small space, and at the same time can provide sufficient rigidity support during penetration into the lunar soil, withstand impact force and maintain a certain penetration direction. It can withstand impact stress from the lunar soil and smoothly reset to the storage roller 16 after the entire penetration process is completed.

[0058] Further, the power module further comprises a holder 15 which is V-shaped and located below the gripper. The lower end of the holder 15 penetrates through the first hole and is fixed on the lower shell 1. The gripper is located inside the holder 15 when moving downward. (When the gripper is subjected to the downward force of the impact hammer 9, the V-shaped holder 15 can ensure the smooth downward movement of the gripper and reduce the horizontal displacement deviation of the gripper)

[0059] Further, the first ferromagnetic body 2 and the second ferromagnetic body 5 are both annular ferromagnetic bodies, and the permanent magnet 10 is an annular permanent magnet.

[0060] Further, the compressible length of the first return spring 13 and the second return spring 14 is not less than 5% of the distance between the first electromagnet and the second electromagnet. The first return spring 13 and the second return spring 14 are designed with small elastic stiffness and large stretching range, which can be compressed during the penetration of the thin shell 19, provide energy for resetting during the resetting stage, and also do not affect the penetration movement of the lunar soil.

[0061] In a second aspect, the application further discloses a control method of an electromagnetic spring lunar soil penetrator with pressure sensing function, comprising the following steps:

[0062] S1, the permanent magnet 10 stores potential energy stage: the PLC controller 20 in the control module controls the current direction and current size of the first coil 3 and the second coil 6, so that the first electromagnet generates a first magnetic field opposite to the magnetic field direction of the permanent magnet 10 (for example, the magnetic field direction of the permanent magnet 10 is the upper N pole and the lower S pole, at this time the first electromagnet forms the upper S pole and the lower N pole magnetic field, and the second electromagnet forms the upper N pole and the lower S pole magnetic field), and the second electromagnet generates a second magnetic field same as the magnetic field direction of the permanent magnet 10, at this time the permanent magnet 10 repels the first electromagnet below it, and the permanent magnet 10 attracts the second electromagnet above it. The first magnetic field and the second magnetic field jointly act on the permanent magnet 10 and the impact hammer 9 along the first guide rail 7 and the second guide rail 8 to the end of the second electromagnet, and the impact hammer 9 stores elastic potential energy and gravitational potential energy. In this stage, the impact hammer 9 is in a static high position state, and the system is fully prepared for the subsequent impact process; under the lunar surface environment, the gravitational potential energy will decrease, and the elastic potential energy will be the main power source;

[0063] S2, the thin shell body 19 release stage (this stage is to prepare for the thin shell body 19 penetration stage): the control module controls the motor 17 to drive the storage roller 16 to rotate, so that the thin shell body 19 is released from the lower end of the predetermined lower shell body 1 to the target length, preparing for the next stage of impact loading, reducing the resistance of the storage roller 16 to the impact hammer 9; At the same time, the initial length of the thin shell body 19 released by the storage roller 16 can be set to a standard value, and in the subsequent work cycle, the softness of the lunar soil can be analyzed according to the penetration depth of the thin shell body 19 in the last round, so as to carry out feedback adjustment, according to the change of lunar soil environment, real-time release of the thin shell body 19 of the next target length;

[0064] S3, impact hammer 9 release and thin shell 19 penetration stage: the control module changes the current direction of the first coil 3, the second coil 6 in step S1, the PLC controller 20 calculates and changes the output current size according to the target penetration depth and the actual penetration depth in the last step and the target power size, at this time, the first magnetic field and the second magnetic field change direction, the permanent magnet 10 is attracted to the first electromagnet below it, and the permanent magnet 10 is repelled by the second electromagnet above it, so that the permanent magnet 10 is subjected to electromagnetic force in the direction of the first electromagnet, the permanent magnet 10 drives the impact hammer 9 to move along the first guide rail 7 and the second guide rail 8 in the direction of the first electromagnet, the elastic potential energy and the gravitational potential energy of the permanent magnet 10 are converted into impact kinetic energy, and acceleration motion with variable acceleration is generated; when the impact hammer 9 moves to collide with the gripper, the first clamping block 11 and the second clamping block 12 clamp the thin shell 19 while driving the thin shell 19 to move downward, realizing the penetration of the thin shell 19 into the lunar soil, and the downward movement of the gripper compresses the first return spring 13 and the second return spring 14 to store energy for the reset stage; when the impact hammer 9 collides with the gripper, the kinetic energy is transferred to the gripper, and the inclined surface structure 901 of the gripper decomposes the impact force into a clamping force transversely to the thin shell 19 and a downward penetration force;

[0065] S4, permanent magnet 10 reset stage: repeat step S1, wherein the PLC controller 20 analyzes the penetration depth of the thin shell 19 in step S3 by receiving the angle signal sent by the displacement sensor 21, and the internal program of the PLC controller 20 can adjust the target penetration length and the current size in the next step in real time according to these feedback information, to ensure that the penetration depth and the penetration force remain in the optimal state during the whole process, to achieve the expected effect, and then adjust the current direction and the current size of the first coil 3 and the second coil 6 in step S1 for optimizing the reset position of the permanent magnet 10 in the next step; Specifically, the control system makes the second electromagnet generate the same magnetic field direction as the permanent magnet 10, and the first electromagnet generates the opposite magnetic field direction of the permanent magnet 10, the impact hammer 9 is restored to the target position under the upward electromagnetic force, at the same time, the first reset spring 13 and the first reset spring 13 are automatically released, the first clamping block 11 and the second clamping block 12 are separated from the thin shell 19 and restored to the original position, and the thin shell 19 remains stationary.

[0066] S5, repeat steps S2 to S4 until the penetration depth of the thin shell 19 analyzed by the PLC controller 20 in step S4 is the target depth.

[0067] The permanent magnet 10 cooperates with the first electromagnet and the second electromagnet, utilizes the characteristics of repelling with the same pole and attracting with the different pole, realizes the storage or release of the elastic potential energy of the permanent magnet 10 by changing the magnetic field direction of the first electromagnet and the second electromagnet, and further changes the relative distance of the impact hammer 9 between the first electromagnet and the second electromagnet; when the impact actuation is performed, the impact hammer 9 is accelerated to move downward with variable acceleration under the electromagnetic force generated by the electromagnetic spring, the elastic potential energy is rapidly released, and is converted into the kinetic energy of the impact hammer 9 as the impact force of the impact hammer 9.

[0068] The working principle of the present application is as follows:

[0069] When the lunar soil penetrator works, the control module as the core coordination unit receives the angle signal collected by the displacement sensor 21 and the pressure signal sent by the pressure sensor 22 through the PLC controller 20, and calculates the next target length (i.e. the penetration depth of the lunar soil) and the target power of the thin shell 19 in real time. The PLC controller 20 adjusts the target length released by the thin shell 19 in the penetration module in advance through the control of the motor 17, and then outputs the first coil 3 current signal and the second coil 6 current signal to the H-bridge circuit submodule and the PWM drive submodule. After receiving the corresponding signals, the H-bridge circuit submodule and the PWM drive submodule control the current direction and the current size of the first coil 3 and the second coil 6 respectively, and the permanent magnet 10 is subjected to upward or downward electromagnetic force, so as to realize the energy storage and impact action of the impact hammer 9 fixedly connected with the permanent magnet 10 in the power module. The power module controls the current of the first coil 3 and the second coil 6 through the control module, realizes the electromagnetic force interaction between the first electromagnet, the second electromagnet and the permanent magnet 10, drives the impact hammer 9 to slide up and down along the first guide rail 7 and the second guide rail 8 by the permanent magnet 10, and the kinetic energy of the impact hammer 9 when moving downward is transmitted to the gripper, so that the first clamping block 11 and the second clamping block 12 clamp and push the thin shell 19 of the penetration module to penetrate the lunar soil. The displacement sensor 21 detects the penetration depth of the thin shell 19 and feeds back to the PLC controller 20, and the PLC controller 20 adjusts and controls the magnetic field direction and the magnetic field size of the first electromagnet and the second electromagnet by using the internal program to realize the energy storage and impact action of the impact hammer 9 in the next step. The motor 17 drives the storage roller 16 to rotate and releases the next release target length of the thin shell 19 in advance according to the motor 17 current signal of the control module, so as to ensure that the penetration depth meets the task requirements.

Claims

1. An electromagnetic spring lunar soil penetrometer with pressure sensing function, comprising a power module, a penetration module and a control module, characterized in that: The power module comprises a U-shaped lower shell (1), a first electromagnet is fixed on the inner surface of the lower end of the lower shell (1), the first electromagnet comprises a first ferromagnetic body (2) and a first coil (3) wound on the surface of the first ferromagnetic body (2), a reverse U-shaped upper shell (4) is installed on the upper part of the lower shell (1), a second electromagnet is fixed on the inner surface of the upper end of the upper shell (4), the second electromagnet comprises a second ferromagnetic body (5) and a second coil (6) wound on the surface of the second ferromagnetic body (5), a first guide rail (7) and a second guide rail (8) are symmetrically fixed on the inner side of the upper shell (4) and / or the inner side of the lower shell (1) along the axis direction of the upper shell (4), the first guide rail (7) and the second guide rail (8) are located between the first electromagnet and the second electromagnet, an impact hammer (9) is slidably connected between the first guide rail (7) and the second guide rail (8), a permanent magnet (10) is fixedly connected to the impact hammer (9), the lower end of the impact hammer (9) is a reverse v-shaped inclined surface structure (901), the power module further comprises a holder located between the impact hammer (9) and the first electromagnet, the holder comprises a first clamping block (11) and a second clamping block (12), the lower part of the first clamping block (11) is connected with one end of a first return spring (13), the lower part of the second clamping block (12) is connected with one end of a second return spring (14), the other end of the first return spring (13) and the other end of the second return spring (14) are respectively connected with the inner surface of the lower end of the lower shell (1), when the impact hammer (9) slides downward along the first guide rail (7) and the second guide rail (8) and collides with the holder, the inclined surface structure (901) causes the first clamping block (11) and the second clamping block (12) to approach each other, the upper shell (4), the first ferromagnetic body (2), the impact hammer (9), the permanent magnet (10), the holder, the second ferromagnetic body (5), and the lower shell (1) are all provided with a first hole along the axis direction of the upper shell (4); the penetration module comprises a storage roller (16), the storage roller (16) is fixed on the upper part of the upper shell (4), a thin shell (19) is wound on the storage roller (16), the storage roller (16) is connected with the power output shaft of a motor (17), the thin shell (19) can be released by the motor (17), the thin shell (19) passes through the first hole and extends to the lower part of the lower shell (1) under the action of the power module and the control module.The control module comprises a PLC controller (20), a displacement sensor (21) and a pressure sensor (22), the PLC controller (20) is electrically connected with the first coil (3), the second coil (6), the motor (17), the displacement sensor (21) and the pressure sensor (22) respectively, the PLC controller (20) comprises an H-bridge circuit submodule and a pulse width modulation driving submodule, the displacement sensor (21) is coaxially installed with the storage roller (16), the displacement sensor (21) detects the angle of rotation of the storage roller (16) and transmits the angle signal to the PLC controller (20), the pressure sensor (22) is installed at the top end of the thin shell (19), the pressure sensor (22) detects the penetration resistance of the thin shell (19) when penetrating the lunar soil and transmits the pressure signal to the PLC controller (20), the PLC controller (20) receives the angle signal and the pressure signal, analyzes and determines the target length of the next step of the thin shell (19) through the internal program, and then outputs the motor (17) current signal to the motor (17) for controlling the motor (17) to drive the storage roller (16) to rotate to release the target length of the thin shell (19) in advance, the PLC controller (20) outputs the first coil (3) current signal and the second coil (6) current signal to the H-bridge circuit submodule and the pulse width modulation driving submodule according to the target length, the target power and the stress direction of the permanent magnet (10), the H-bridge circuit submodule and the pulse width modulation driving submodule receive the first coil (3) current signal and the second coil (6) current signal, and control the current size and direction of the first coil (3) and the second coil (6); the power module converts electric energy into kinetic energy of the impact hammer (9) by using an electromagnetic spring, the penetration module drives the thin shell (19) to penetrate the lunar soil by using the kinetic energy of the impact hammer (9), and the control module adjusts the size of the electric energy output by the power module by using the sensor to sense the lunar soil penetration depth and resistance of the thin shell (19) in the previous step.

2. The lunar soil penetrator of claim 1, wherein The first clamping block (11) and the second clamping block (12) are symmetrically distributed along the axis direction of the upper shell (4), and the outer side of the first clamping block (11) and the second clamping block (12) away from the axis of the upper shell (4) is a curved surface structure.

3. The lunar soil penetrator of claim 1, wherein The slope structure (901) at the lower end of the impact hammer (9) is symmetrically distributed along the axis direction of the upper shell (4), and the diameter of the inverted V-shaped opening is greater than the vertical projection diameter of the first clamping block (11) and the second clamping block (12).

4. The lunar soil penetrator of claim 1, wherein The power module further comprises a retainer (15) which is a V-shaped opening and is located below the holder, the lower end of the retainer (15) passes through the first hole and is fixed on the lower shell (1), and the holder is located inside the retainer (15) when moving downward.

5. The lunar soil penetrator of claim 1, wherein The first ferromagnetic body (2) and the second ferromagnetic body (5) are annular ferromagnetic bodies, and the permanent magnet (10) is an annular permanent magnet.

6. The lunar soil penetrator of claim 1, wherein The compressible length of the first return spring (13) and the second return spring (14) is not less than 5% of the distance between the first electromagnet and the second electromagnet.

7. A control method of an electromagnetic spring lunar soil penetrometer with pressure sensing function, based on the lunar soil penetrometer according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: S1, the PLC controller (20) in the control module controls the current direction and current size of the first coil (3) and the second coil (6), so that the first electromagnet generates a first magnetic field opposite to the magnetic field direction of the permanent magnet (10), and the second electromagnet generates a second magnetic field same as the magnetic field direction of the permanent magnet (10), and the first magnetic field and the second magnetic field jointly act on the permanent magnet (10) and the impact hammer (9) to lift the permanent magnet (10) and the impact hammer (9) along the first guide rail (7) and the second guide rail (8) to one end of the second electromagnet; S2, the control module controls the motor (17) to drive the storage roller (16) to rotate, so that the thin shell (19) is released to the target length; S3, the control module changes the current direction of the first coil (3) and the second coil (6) in step S1, so that the permanent magnet (10) is subjected to an electromagnetic force towards the first electromagnet, and the permanent magnet (10) drives the impact hammer (9) to move towards the first electromagnet along the first guide rail (7) and the second guide rail (8); when the impact hammer (9) moves to collide with the holder, the first clamping block (11) and the second clamping block (12) drive the thin shell (19) to move downward at the same time of clamping the thin shell (19) in step S2, so as to realize the penetration of the thin shell (19) into the lunar soil, and the holder moves downward at the same time of compressing the first return spring (13) and the second return spring (14); S4, repeat step S1, wherein the PLC controller (20) receives the angle signal sent by the displacement sensor (21) and the pressure signal sent by the pressure sensor (22), analyzes the penetration depth of the thin shell (19) in step S3, and adjusts the current direction and current size of the first coil (3) and the second coil (6) in step S1; S5, repeat steps S2 to S4 until the penetration depth of the thin shell (19) analyzed by the PLC controller (20) in step S4 is the target depth.

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