A sample escape prevention device and sampling method for small celestial body sampling

Abstract

This invention discloses a sample escape prevention device and sampling method for small celestial body sampling. The escape prevention device includes a fixed cylinder, a double-fork arm assembly, a moving cylinder assembly, a cylindrical linear motor assembly, a high-elasticity memory alloy brush filament door assembly, a positioning switch assembly, a clamping assembly, and a release spring. One end of the moving cylinder assembly is fitted onto the outer circumference of the fixed cylinder via the release spring. One end of the double-fork arm assembly is fixedly connected to the fixed cylinder, and the other end supports and fixes the clamping assembly. The clamping assembly is located on the outer circumference of the moving cylinder assembly, limiting the release spring to a compressed state. After the compression assembly is unlocked by firing, the release spring is released, and its elastic force drives the moving cylinder assembly to retract towards the inlet end of the fixed cylinder. The positioning switch assembly is triggered when the moving cylinder assembly reaches its positioning position, collecting the positioning signal of the moving cylinder assembly. The other end of the moving cylinder assembly is fixedly connected to the cylindrical linear motor assembly, which, when energized, extends and retracts to control the opening and closing of the high-elasticity memory alloy brush filament door assembly. This invention can achieve the escape prevention function during sample collection.

Description

Technical Field

[0001] This invention relates to the field of space exploration sampling and return technology, specifically to a sample escape prevention device and sampling method for sampling small celestial bodies. Background Technology

[0002] With the implementation of deep space sampling and exploration missions both domestically and internationally, while successfully acquiring samples, significant on-orbit risks have also been encountered. One of the most recent sampling mission crises occurred on October 22, 2020. After completing its sampling mission and returning to its docking point fully loaded with stellar regolith, the onboard sample monitoring camera showed that the collected sample was slowly leaking from the sampler. Analysis indicated that the polyester film seal of the sampler had been wedged open by the collected stellar regolith, causing the acquired Bennu asteroid sample to leak into space through this gap. This emergency led ground personnel to make an emergency decision to abandon the planned on-orbit measurement of sample volume and cancel multiple planned sampling missions, jumping directly to the overall transfer and repackaging of the sampler. This on-orbit incident on the OSIRIS mission serves as a stark reminder that the reliability of sample escape prevention measures must be considered in subsequent space sampling missions.

[0003] To address the need for sample escape prevention in space sampling missions, the OSIRIS mission employed a "gas-blown polyester film baffle" scheme. This scheme utilizes airflow pressure to open the polyester film baffle in one direction, and the baffle resets after the gas flow ceases. Once the sample enters the compartment, it is less likely to overflow. Combined with a gas switch control strategy, this can meet the needs of multiple on-orbit missions. However, a drawback of this scheme is the risk of the baffle becoming stuck due to particles if the sample volume is too large, leading to sample loss. The Huihe sample return mission used a "bottom-end baffle" scheme. The sampling device is equipped with three independent core tubes, which can be accelerated to a maximum speed of 90 m / s to penetrate the comet's surface via an ejection mechanism. Since the bottom of the core tube is open during sampling, a baffle mechanism is designed at the bottom of the core tube to prevent sample spillage during transfer. Once sample collection is complete, the baffle closes to prevent sample drop. However, this scheme has the limitation of being a one-time use, non-repeatable switch. The Enceladus sampling project proposed a "fish trap with flexible fingers." Its sample holding mechanism features a fish trap with flexible fingers extending radially from the sample tube's edge to its central axis. When the sample tube is inserted into the sheath against the bottom shoulder, the fingers deform against the tube wall, opening the central portion of the tube. This openness allows the tube to sample materials with low permeability resistance, such as loose dust. When the sample tube is removed from the sheath, the fingers release and return to a relaxed position, closing the bottom opening. This design can hold lighter samples in the tube without them falling and allows for multiple sampling operations. However, a drawback is that it is difficult to hold heavier samples inside the tube.

[0004] In summary, the space sampling escape prevention scheme focuses on stability and safety under space working conditions, while also needing to adapt to the requirements of multiple sampling tasks. The device must ensure that the sample passes through smoothly, while preventing the sample from going back or escaping. Summary of the Invention

[0005] In view of this, the present invention provides a sample escape prevention device and sampling method for small celestial body sampling, which can realize the escape prevention function during the sample collection process.

[0006] The technical solution adopted in this invention is as follows:

[0007] A sample escape prevention device for sampling small celestial bodies includes a fixed cylinder, a double fork arm assembly, a moving cylinder assembly, a cylindrical linear motor assembly, a high-elasticity memory alloy brush filament door assembly, a position switch assembly, a clamping assembly, and a separation spring.

[0008] One end of the moving cylinder assembly is fitted onto the outer circumference of the fixed cylinder via a separation spring, with the fixed cylinder serving as the sampling inlet of the device. One end of the double fork arm assembly is fixedly connected to the fixed cylinder, and the other end of the double fork arm assembly supports and fixes the clamping assembly. The clamping assembly is located on the outer circumference of the moving cylinder assembly and is used to initially limit the separation spring to a compressed state. After the compression assembly is unlocked by ignition, the separation spring is released, and its elastic force drives the moving cylinder assembly to retract towards the inlet end of the fixed cylinder. The position switch assembly is located on the double fork arm assembly and is triggered after the moving cylinder assembly moves to the correct position, used to collect the position signal of the moving cylinder assembly.

[0009] The other end of the moving cylinder assembly is fixedly connected to a cylindrical linear motor assembly. The cylindrical linear motor assembly is nested with the high-elasticity memory alloy brush filament door assembly, and the high-elasticity memory alloy brush filament door assembly is opened and closed by being energized to extend and retract.

[0010] Furthermore, the cylindrical linear motor assembly includes a mover, a stator, a magnetic chuck, a permanent magnet, a pressure ring, and an inner guide rail;

[0011] The stator is used to generate a rotating magnetic field, which generates an axial force that moves the mover. The mover is supported by two stepped surfaces of the inner guide rail, forming a sliding friction pair. The magnetic attraction is fixed on the stator, and the permanent magnet is fixed on the mover and limited by the pressure ring. When the stator is energized with positive DC current, the mover is in the extended state. When the stator is energized with reverse DC current, the mover is in the retracted state. When the mover is in the extended state, the magnetic attraction interacts with the permanent magnet to provide a retaining force for the mover when the power is off.

[0012] Furthermore, the stator includes a housing, a coil frame, and winding coils;

[0013] The winding coil is glued to the coil frame to form a whole and then screwed onto the housing; after the winding coil carries a specified current, it interacts with the magnetic field of the mover to generate an axial force that moves the mover.

[0014] Furthermore, the position switch assembly includes an insulating through-ring, a double-hole washer, a middle plate, a contact plate, a screw, and upper and lower plates;

[0015] Two contact pieces are fixed to the double fork arm assembly in parallel and spaced apart by upper and lower pieces, and the two contact pieces are insulated from each other by a middle piece; the upper and lower pieces are fixed by two screws, and the two screws are fixed to the end face of the double fork arm assembly by insulating rings, and a double-hole washer is provided between the screws and the end face of the double fork arm assembly; the two contact pieces make contact and conduction, and the cable at the tail of the contact piece receives the signal to realize the function of collecting the position signal.

[0016] Furthermore, the clamping assembly adopts a clamping rod method, and the clamping rod is arranged along the axial direction of the moving cylinder assembly.

[0017] Furthermore, the high-elasticity memory alloy brush bristle door assembly includes high-elasticity memory alloy brush bristles, a brush bristle mounting plate, and a brush bristle pressure plate;

[0018] The brush bristle press plate presses the high-elasticity memory alloy brush bristles onto the brush bristle mounting plate. The high-elasticity memory alloy brush bristles point outwards towards the axis of the brush bristle mounting plate. Multiple high-elasticity memory alloy brush bristles are evenly distributed on the brush bristle mounting plate and converge at the axis in a closed state.

[0019] Furthermore, an H-bridge circuit is used to control the forward or reverse DC current supply to the stator.

[0020] An escape-prevention sampling method for small celestial bodies, employing the escape-prevention device as described in claim 2, comprises the following steps:

[0021] Step 1: The cylindrical linear motor assembly is initially de-energized. The mover extends to keep the high-elasticity memory alloy brush filament door assembly fully open, and the separation spring is in a compressed state. At this time, the sample acquisition channel is unobstructed.

[0022] Step 2: Before the sampling task begins, the cylindrical linear motor assembly is powered on, the mover extends to ensure that the high-elasticity memory alloy brush filament door assembly is fully open, the separation spring is still in the compressed state, and the collected sample is transferred to the packaging container through the sample collection channel of the anti-escape device.

[0023] Step 3: After a single sampling is completed, the cylindrical linear motor assembly is powered by reverse DC current. The mover retracts after overcoming the resistance of the brush filament door and the magnetic attraction used to retain power off. The high-elasticity memory alloy brush filament door assembly closes, and the separation spring remains in the compressed state. At this time, the sample acquisition channel is closed to prevent the sample from escaping.

[0024] Step 4: Repeat until the sampling task is completed. After the cylindrical linear motor assembly is powered on, the mover retracts, the high-elasticity memory alloy brush filament door assembly closes, the compression assembly is unlocked by fire, the separation spring is released, and the moving cylinder assembly retracts towards the fixed cylinder. At this time, the sample collection channel and the sealed container are completely physically separated.

[0025] Beneficial effects:

[0026] 1. This invention employs a two-stage drive to control sample flow. The first-stage drive uses a cylindrical linear motor assembly to reciprocate and control the opening and closing of a high-elasticity memory alloy brush filament assembly. The second-stage drive utilizes a pyrotechnic unlocking mechanism to release a high-load-bearing separation spring, physically isolating the sample acquisition channel from the packaging container. This solves the problem of controlling the opening or closing of the sample acquisition channel under the requirements of on-orbit repetitive sampling tasks, achieving a sample escape prevention design. Furthermore, the dual-drive mode ensures independent control of functions while also providing backup for each other.

[0027] Secondly, the on-orbit escape prevention working status is fed back by the separation of the moving cylinder assembly triggering the positioning switch assembly.

[0028] 2. The cylindrical linear motor assembly of this invention has a power-off retention function, ensuring the sample acquisition channel remains open, thus mitigating the risk of failure and guaranteeing the implementation of on-orbit sampling missions. In the initial state, the power-off retention function ensures the sample acquisition channel remains open. During launch, the motor mover extends to ensure the shape memory alloy brush filament door opens, adapting to the impact loads of acceleration during flight, ensuring the smooth operation of the sample acquisition channel during the first sampling mission, and improving the reliability of on-orbit missions.

[0029] 3. The cylindrical linear motor assembly of the present invention has the advantages of high output density, simple mechanism and control, small size and light weight, and internal structure that facilitates sample transport. The extension / retraction function of the motor mover is matched with the opening / closing of the shape memory alloy brush filament door to ensure control of sample flow.

[0030] 4. This invention can selectively control sample particles by setting the number and shape of the brush filaments in the high-elasticity memory alloy brush filament assembly and changing the density of the planar arrangement of the brush filament assembly, according to the requirements of the sample particles of the target small celestial body.

[0031] 5. This invention has the function of rapid response and instantaneous action. The electromagnetic drive and fire attack separation included in the design principle of the device itself are both capable of completing the movement in milliseconds. Attached Figure Description

[0032] Figure 1 This is a cross-sectional view of the mechanical structure of the device of the present invention;

[0033] Figure 2 This is a schematic diagram of the mechanical structure of the device of the present invention;

[0034] Figure 3 for Figure 2 Right view;

[0035] Figure 4(a) is a schematic diagram of the cylindrical linear motor assembly of the device of the present invention;

[0036] Figure 4(b) is a cross-sectional view of the cylindrical linear motor assembly of the device of the present invention;

[0037] Figure 5(a) is a schematic diagram of the position switch assembly of the device of the present invention;

[0038] Figure 5(b) is a top view of Figure 5(a);

[0039] Figure 6(a) is a schematic diagram of the high-elasticity memory alloy brush filament assembly of the device of the present invention;

[0040] Figure 6(b) is a cross-sectional view of the high-elasticity memory alloy brush filament assembly of the device of the present invention;

[0041] Figures 7(a), 7(b), and 7(c) are schematic diagrams of the driving principle of the cylindrical linear motor assembly of the present invention in the initial power-off holding state, the power-on extended working state, and the power-on retracted working state, respectively.

[0042] Figures 8(a) and 8(b) are schematic diagrams of the device of the present invention in the initial pressing state and the release and separation state, respectively.

[0043] Among them, 1-moving cylinder assembly, 2-moving cylinder baffle assembly, 3-double fork arm assembly, 4-cable bracket assembly, 5-clamping assembly, 6-cylindrical linear motor assembly, 7-position switch assembly, 8-high elastic memory alloy brush filament door assembly, 9-fixed cylinder, 10-separation spring, 11-semi-ring gasket, 12-container funnel, 13-pipe funnel liner, 14-pipe funnel, 15-machine housing, 16-inner guide rail, 17-moving element, 18-coil assembly, 1 9-Pressure ring, 20-Magnetic yoke, 21-Magnetic steel, 22-Motor magnet, 23-Stator yoke, 24-Insulating ring, 25-Double hole washer, 26-Middle plate, 27-Contact plate, 28-Upper and lower plates, 29-Hex socket head cap screw, 30-Anti-escape signal line connector, 31-High-elasticity memory alloy brush filament, 32-Brush filament mounting plate, 33-Brush filament pressure plate, 34-Magnetic attraction, 35-Permanent magnet, 36-Stepped surface, 37-Stator. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] This invention provides a sample escape prevention device for small celestial body sampling, such as... Figures 1-3 As shown, it includes a fixed cylinder, a double fork arm assembly 3, a moving cylinder assembly 1, a double fork arm assembly 3, a cylindrical linear motor assembly 6, a high-elasticity memory alloy brush filament door assembly 8, a position switch assembly 7, a clamping assembly 5, and a separation spring 10.

[0046] One end of the moving cylinder assembly 1 is fitted onto the outer circumference of the fixed cylinder 9 via a separation spring 10, and is also fixedly connected to the moving cylinder baffle assembly 2. The fixed cylinder 9 serves as the sampling inlet of the device. The inlet end of the fixed cylinder 9 is fixedly connected to a pipe funnel 14, and a pipe funnel liner 13 is provided on the inner wall of the pipe funnel 14. One end of the double fork arm assembly 3 is fixedly connected to the pipe funnel 14 and the fixed cylinder 9 via a semi-ring washer 11 and screws. The other end of the double fork arm assembly 3 supports and fixes the clamping assembly 5. The clamping assembly 5 is located on the outer circumference of the moving cylinder assembly 1 and is used to limit the separation in the initial state. Spring 10 is in a compressed state. After the compression assembly is unlocked by the flame, spring 10 is released, and its elastic force drives the moving cylinder assembly 1 to retract towards the inlet end of the fixed cylinder 9. The position switch assembly 7 is set on the double fork arm assembly 3 and is triggered after the moving cylinder assembly 1 moves to the position. It is used to collect the position signal of the moving cylinder assembly 1. The other end of the moving cylinder assembly 1 is fixedly connected to the cylindrical linear motor assembly 6. The cylindrical linear motor assembly 6 is nested with the high-elasticity memory alloy brush filament door assembly 8. The extension and retraction of the high-elasticity memory alloy brush filament door assembly 8 is controlled by electricity. The outlet end of the high-elasticity memory alloy brush filament door assembly 8 is connected to the container funnel 12 for conveying samples to the packaging container.

[0047] One end of the cable bracket assembly 4 is connected to the power supply cable of the cylindrical linear motor assembly 6, and the other end is connected to an external power source.

[0048] As shown in Figures 4(a) and 4(b), the cylindrical linear motor assembly 6 includes a mover 17, a stator 37, a magnetic 34, a permanent magnet 35, a pressure ring 19, and an inner guide rail 16. The stator 37 generates a rotating magnetic field, which generates an axial force that moves the mover 17. The mover 17 is supported by two stepped surfaces 36 of the inner guide rail 16, forming a sliding friction pair. The magnetic 34 is fixed on the stator 37, and the permanent magnet 35 is fixed on the mover 17 and axially limited by the pressure ring 19. When the stator 37 is energized with a positive DC current, the mover 17 is in an extended state. When the stator 37 is energized with a reverse DC current, the mover 17 is in a retracted state. When the mover 17 is in an extended state, the magnetic 34 and the permanent magnet 35 interact to provide a power-off holding force for the mover 17.

[0049] The stator 37 includes a housing 15 and a coil assembly 18. The coil assembly 18 is formed by bonding the winding coils to the coil frame and then screwing them onto the housing 15. When a specified current is passed through the winding coils, they interact with the magnetic field of the mover 17 to generate an axial force that moves the mover 17. The stator yoke 23, magnetic yoke 20, and magnetic magnet 21 are also known as magnetic 34. The stator yoke 23, magnetic magnet 21, and magnetic yoke 20 are all bonded to the coil frame.

[0050] The moving magnet 22 is the permanent magnet 35, which generates the main magnetic field for linear motion and is used to generate thrust. It is also part of the magnetic attraction circuit. The stator yoke 23, the magnetic attraction yoke 20, the magnetic attraction magnet 21 and the moving magnet 22 interact to generate magnetic attraction.

[0051] To prevent the motor's mover 17 from slipping out of the brush gate during launch and maneuvering, the magnetic attraction 34 interacts with the permanent magnet 35 to generate a magnetic attraction force, providing a power-off holding force, as shown in Figure 7(a). Simultaneously, during the process of the motor pulling out the mover 17 (from the extended state to the retracted state), in addition to overcoming the sliding pair friction force (negligible) and the brush gate resistance f, it must also overcome... s It is also necessary to overcome the magnetic attraction F used for power-off retention. mag Therefore, the load F of the linear motor m Includes a defined brush filament gate resistance and a de-energized holding magnetic force (i.e., F) proportional to the mass of the mover. m ≥F mag +f s ).

[0052] By combining the electromagnetic equations and mechanical equations of the linear motor, the relationship between the position, current, and thrust of the motor and time during operation is obtained. The mechanical equations and electromagnetic equations are as follows (1).

[0053]

[0054] Where t is time, x is position, v is velocity, i is current, U is voltage, m is mover mass, L is winding inductance, R is winding resistance, e is back EMF, and F is... mag For magnetic attraction, F m f is the thrust of the motor. s This is friction.

[0055] F m , e and F mag The functional relationship is shown in equation (2) below, which can be obtained through electromagnetic simulation.

[0056]

[0057] An H-bridge circuit is used to control the motor. Meanwhile, to avoid damage caused by excessive current, a closed-loop current control is employed. The voltage across the winding coil is adjusted by chopping, thereby regulating the winding coil current, as shown in Figures 7(b) and 7(c).

[0058] As shown in Figure 7(b), when the motor mover 17 extends, transistor T4 (the switch shown in the lower right of the figure) remains on, transistor T3 (the switch shown in the upper right of the figure) remains off, and transistors T1 (the switch shown in the upper left of the figure) and T2 (the switch shown in the lower left of the figure) alternately switch on and off. The voltage across the winding coil is adjusted by regulating the switching time ratio of transistors T1 (the switch shown in the upper left of the figure) and T2 (the switch shown in the lower left of the figure). The given current is positive, and after a certain time T, the power is turned off, completing the insertion of the motor mover 17 into the flexible brush filament door.

[0059] As shown in Figure 7(c), when the motor mover 17 retracts, transistor T2 (shown in the lower left corner) remains on, transistor T1 (shown in the upper left corner) remains off, and transistors T3 (shown in the upper right corner) and T4 (shown in the lower right corner) alternately switch on and off. The voltage across the winding coil is adjusted by regulating the switching time ratio of transistors T3 (shown in the upper right corner) and T4 (shown in the lower right corner). With a negative current, the power is applied for a certain time T and then de-energized, completing the action of the motor mover 17 pulling out the flexible brush filament door.

[0060] As shown in Figures 6(a) and 6(b), the high-elasticity memory alloy brush bristle door assembly 8 includes high-elasticity memory alloy brush bristles 31, a brush bristle mounting plate 32, and a brush bristle pressure plate 33. The brush bristle pressure plate 33 presses the high-elasticity memory alloy brush bristles 31 onto the brush bristle mounting plate 32. The high-elasticity memory alloy brush bristles 31 point outwards towards the axis of the brush bristle mounting plate 32. Multiple high-elasticity memory alloy brush bristles 31 are evenly distributed on the brush bristle mounting plate 32 and converge at the axis in a closed state. The scheme of evenly distributing multiple flexible brush bristles can avoid the failure mode similar to the entire flip-up baffle of OSIRIS. The maximum gap D of the brush bristle door is... max The maximum particle size d that can be blocked is determined by:

[0061] d≤D max (3)

[0062] As shown in Figures 5(a) and 5(b), the position switch assembly 7 includes an insulating ring 24, a double-hole washer 25, a middle plate 26, a contact piece 27, a hexagon socket head cap screw 29, and upper and lower plates 28. The two contact pieces 27 are fixed to the double fork arm assembly 3 in parallel and at intervals through the upper and lower plates 28, and the two contact pieces 27 are insulated from each other by the middle plate 26. The upper and lower plates 28 are fixed by two hexagon socket head cap screws 29, and the two hexagon socket head cap screws 29 are fixed to the end face of the double fork arm assembly 3 through the insulating ring 24. A double-hole washer 25 is provided between the hexagon socket head cap screw 29 and the end face of the double fork arm assembly 3.

[0063] The upper and lower plates 28 are made of polyimide, which has excellent thermal stability and dielectric properties. The two contact plates 27 are made of beryllium bronze with gold plating. The working principle is that the moving cylinder assembly 1 contacts the switch plate to achieve bending, and the short arm of the contact switch achieves circuit conduction, that is, the two contact plates 27 are in contact and conduction. The cable at the tail of the contact plate 27 receives the signal and connects to the anti-escape function signal line connector 30 to realize the function of collecting the arrival signal.

[0064] The clamping assembly 5 adopts a clamping rod method. After connecting the double fork arm assembly 3 and the clamping seat of the clamping assembly 5, it is fixed to the mounting surface of the entire device. The clamping rod (set along the axis of the moving cylinder assembly 1) is cut by the pyrotechnic cutter to unlock and separate the spring 10, which drives the moving cylinder to retract towards the fixed cylinder, thus completing the separation of the escape prevention device from the packaging container. For detailed motion diagrams, please refer to Figures 8(a) and 8(b).

[0065] The entire sampling cycle consists of four operating modes: power-off holding mode under clamping configuration, power-on extension mode under clamping configuration, power-on retraction mode under clamping configuration, and power-on retraction mode under release configuration. The specific sampling method steps are as follows:

[0066] Step 1: In the initial state of the cylindrical linear motor assembly 6, the linear motor is de-energized, the mover 17 extends to keep the flexible brush filament door fully open, and the separation spring 10 is in a compressed state. At this time, the sample collection channel is unobstructed.

[0067] Step 2: Before each sampling task begins, the cylindrical linear motor assembly 6 is powered on, the mover 17 extends to ensure that the flexible brush filament door is fully opened, the separation spring 10 is still in the compressed state, and the collected sample is transferred to the packaging container through the sample collection channel of the anti-escape device.

[0068] Step 3: After a single sampling is completed, the cylindrical linear motor assembly 6 is energized, the mover 17 retracts, the flexible brush filament door closes, and the separation spring 10 remains in a compressed state. At this time, the sample acquisition channel is closed to prevent the sample from escaping.

[0069] Step 4: Repeat until the sampling task is completed. After the cylindrical linear motor assembly 6 is powered on, the mover 17 retracts, the flexible brush door closes, the compression assembly is unlocked by fire, and the separation spring 10 is released. At this time, the sample collection channel is completely physically separated from the sealed container.

[0070] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sample escape prevention device for sampling small celestial bodies, characterized in that, Includes a fixed cylinder, a double fork arm assembly, a moving cylinder assembly, a cylindrical linear motor assembly, a high-elasticity memory alloy brush filament door assembly, a position switch assembly, a clamping assembly, and a release spring; One end of the moving cylinder assembly is fitted onto the outer circumference of the fixed cylinder via a separation spring, with the fixed cylinder serving as the sampling inlet of the device. One end of the double fork arm assembly is fixedly connected to the fixed cylinder, and the other end of the double fork arm assembly supports and fixes the clamping assembly. The clamping assembly is located on the outer circumference of the moving cylinder assembly and is used to initially limit the separation spring to a compressed state. After the compression assembly is unlocked by ignition, the separation spring is released, and its elastic force drives the moving cylinder assembly to retract towards the inlet end of the fixed cylinder. The position switch assembly is located on the double fork arm assembly and is triggered after the moving cylinder assembly moves to the correct position, used to collect the position signal of the moving cylinder assembly. The other end of the moving cylinder assembly is fixedly connected to a cylindrical linear motor assembly. The cylindrical linear motor assembly is nested with the high-elasticity memory alloy brush filament door assembly, and the high-elasticity memory alloy brush filament door assembly is opened and closed by being energized to extend and retract.

2. The sample escape prevention device for small celestial body sampling as described in claim 1, characterized in that, The cylindrical linear motor assembly includes a mover, a stator, a magnetic chuck, a permanent magnet, a pressure ring, and an inner guide rail. The stator is used to generate a rotating magnetic field, which generates an axial force that moves the mover. The mover is supported by two stepped surfaces of the inner guide rail, forming a sliding friction pair. The magnetic attraction is fixed on the stator, and the permanent magnet is fixed on the mover and limited by the pressure ring. When the stator is energized with positive DC current, the mover is in the extended state. When the stator is energized with reverse DC current, the mover is in the retracted state. When the mover is in the extended state, the magnetic attraction interacts with the permanent magnet to provide a retaining force for the mover when the power is off.

3. The sample escape prevention device for small celestial body sampling as described in claim 2, characterized in that, The stator includes a housing, a coil frame, and winding coils; The winding coil is glued to the coil frame to form a whole and then screwed onto the housing; after the winding coil carries a specified current, it interacts with the magnetic field of the mover to generate an axial force that moves the mover.

4. The sample escape prevention device for small celestial body sampling as described in claim 1, characterized in that, The position switch assembly includes an insulating ring, a double-hole washer, a middle plate, a contact plate, a screw, and upper and lower plates; Two contact pieces are fixed to the double fork arm assembly in parallel and spaced apart by upper and lower pieces, and the two contact pieces are insulated from each other by a middle piece; the upper and lower pieces are fixed by two screws, and the two screws are fixed to the end face of the double fork arm assembly by insulating rings, and a double-hole washer is provided between the screws and the end face of the double fork arm assembly; the two contact pieces make contact and conduction, and the cable at the tail of the contact piece receives the signal to realize the function of collecting the position signal.

5. The sample escape prevention device for small celestial body sampling as described in claim 1, characterized in that, The clamping assembly adopts a clamping rod method, and the clamping rod is set along the axial direction of the moving cylinder assembly.

6. The sample escape prevention device for small celestial body sampling as described in claim 1, characterized in that, The high-elasticity memory alloy brush bristle door assembly includes high-elasticity memory alloy brush bristles, a brush bristle mounting plate, and a brush bristle pressure plate. The brush bristle press plate presses the high-elasticity memory alloy brush bristles onto the brush bristle mounting plate. The high-elasticity memory alloy brush bristles point outwards towards the axis of the brush bristle mounting plate. Multiple high-elasticity memory alloy brush bristles are evenly distributed on the brush bristle mounting plate and converge at the axis in a closed state.

7. The sample escape prevention device for small celestial body sampling as described in any one of claims 2-6, characterized in that, An H-bridge circuit is used to control the forward or reverse DC current supply to the stator.

8. A sample escape prevention sampling method for small celestial body sampling, characterized in that, Using the escape prevention device as described in claim 2, the sampling method steps are as follows: Step 1: The cylindrical linear motor assembly is initially de-energized. The mover extends to keep the high-elasticity memory alloy brush filament door assembly fully open, and the separation spring is in a compressed state. At this time, the sample acquisition channel is unobstructed. Step 2: Before the sampling task begins, the cylindrical linear motor assembly is powered on, the mover extends to ensure that the high-elasticity memory alloy brush filament door assembly is fully open, the separation spring is still in the compressed state, and the collected sample is transferred to the packaging container through the sample collection channel of the anti-escape device. Step 3: After a single sampling is completed, the cylindrical linear motor assembly is powered by reverse DC current. The mover retracts after overcoming the resistance of the brush filament door and the magnetic attraction used to retain power off. The high-elasticity memory alloy brush filament door assembly closes, and the separation spring remains in the compressed state. At this time, the sample acquisition channel is closed to prevent the sample from escaping. Step 4: Repeat until the sampling task is completed. After the cylindrical linear motor assembly is powered on, the mover retracts, the high-elasticity memory alloy brush filament door assembly closes, the compression assembly is unlocked by fire, the separation spring is released, and the moving cylinder assembly retracts towards the fixed cylinder. At this time, the sample collection channel and the packaging container are completely physically separated.

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