A method for adjusting buoyancy based on a multi-cascaded nested cylinder

Abstract

The application discloses a kind of based on multi-level cascade nested cylinder buoyancy adjusting method, belong to surveying technical field, comprising: (1), the corresponding depth adjustment range when each cascade nested cylinder is respectively regarded as adjusting object is generated look-up table;(2), identify current adjustment mode, obtain the current depth of device, determine the cascade nested cylinder as adjusting object according to current depth, and combine adjustment mode control motor drives piston action, adjust the drainage volume of cascade nested cylinder as adjusting object.This method selects the cascade nested cylinder with smaller inner diameter as adjusting object to control buoyancy in deep water by setting different inner diameters between cascade nested cylinders, selects the cascade nested cylinder with larger inner diameter as adjusting object to control buoyancy in shallow water, and motor only needs to output smaller thrust to realize buoyancy adjustment.Control buoyancy to reach maximum when rising to water surface, increase the height of antenna floating out of water surface, and then facilitate data transmission.

Description

Technical Field

[0001] This invention belongs to the field of surveying and mapping technology, specifically, it relates to a buoyancy adjustment method based on multi-level nested cylinders. Background Technology

[0002] Continuous buoyancy adjustment for underwater mobile observation devices employs two methods: oil suction / discharge and water suction / discharge. The oil suction / discharge method uses a combination of air and oil pumps inside the platform to siphon oil from both the inner and outer oil bladders, thereby altering buoyancy by changing the platform's volume and thus regulating its vertical reciprocating motion. The water suction / discharge method combines a water valve with a high-pressure air pump to discharge water from the ballast water tanks to increase buoyancy, while water pressure is used to inject water into the ballast water tanks to reduce buoyancy.

[0003] Both of the aforementioned buoyancy adjustment methods have technical drawbacks. The oil-suction method relies on a dual pressurization mechanism—an internal air pump and a refueling pump—to pump oil from an inner oil tank to an outer oil tank, providing additional buoyancy. This results in a complex electrical structure and large space requirement, making it suitable for small-volume underwater mobile observation devices (AUVs, underwater gliders, etc.) in deep water (≥2000m), but not for small, shallow-water observation devices. Furthermore, with a relatively small buoyancy adjustment range (1-2L), the pumping speed is typically 0.003-0.02mL / s, requiring pumping time exceeding 4 hours. During this time, the motor operates continuously, significantly impacting the platform's electromagnetic interference and motion stability. The water-suction method, on the other hand, is mostly used in large-volume equipment like submarines. It utilizes multiple water-sucking compartments to achieve submersion, and then uses a high-pressure air pump to blow water out of the compartments to achieve surfacing. This method suffers from slow adjustment speed, long adjustment time, high power consumption, and low efficiency.

[0004] If an underwater mobile observation device is conducting vertical profile observations in shallow sea areas shallower than 400m, a simple, stable, reliable, and efficient buoyancy adjustment method needs to be invented to provide reciprocating power for the small underwater mobile observation device, so that the observation system can be suspended at a set water depth for observation and can also rise to the surface in a timely and rapid manner to send back data. Summary of the Invention

[0005] To address the technical problems of long buoyancy adjustment cycles and continuous interference with the platform's measuring devices in existing underwater mobile observation platforms, this invention proposes a buoyancy adjustment method based on multi-tiered nested cylinders, which can solve the aforementioned problems.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A buoyancy adjustment method based on multi-tiered nested cylinders, wherein the multi-tiered nested cylinders include a first tiered nested cylinder, a second tiered nested cylinder, and a third tiered nested cylinder. A piston is provided in the third tiered nested cylinder. The inner diameter of the third tiered nested cylinder is smaller than the inner diameters of the first tiered nested cylinder and the second tiered nested cylinder. A motor pushes or pulls the piston axially via a push rod. When the device is at different underwater depths, buoyancy is adjusted by different tiered nested cylinders. In shallow water, the tiered nested cylinder with a larger inner diameter is selected as the adjustment object for buoyancy control, while in deep water, the tiered nested cylinder with a smaller inner diameter is selected as the adjustment object for buoyancy control.

[0008] The buoyancy adjustment method includes:

[0009] (1) Generate a lookup table for the depth adjustment range corresponding to each level of nested cylinder when they are used as adjustment objects and store it in the storage module;

[0010] (2) Identify the current adjustment mode, obtain the current depth h of the device, determine the cascaded nested cylinder as the adjustment object based on the current depth h, and control the motor to drive the piston to move in combination with the adjustment mode, adjust the drainage volume of the cascaded nested cylinder as the adjustment object, and realize the buoyancy adjustment of the device.

[0011] The adjustment modes include a diving adjustment mode, an adaptive suspension adjustment mode, and a multi-level nested cylinder gradient buoyancy adjustment mode.

[0012] In some embodiments, the lower end of the third cascaded nested cylinder extends into the second cascaded nested cylinder and can move axially relative to the second cascaded nested cylinder. The first cascaded nested cylinder is located below the second cascaded nested cylinder. When the motor pushes the piston outward through the push rod, the piston moves towards the bottom of the third cascaded nested cylinder in the third cascaded nested cylinder. After abutting the bottom of the third cascaded nested cylinder, the piston can drive the third cascaded nested cylinder to move downward relative to the second cascaded nested cylinder until the lower end of the third cascaded nested cylinder passes through the lower end of the second cascaded nested cylinder and extends into the first cascaded nested cylinder, moving axially relative to the first cascaded nested cylinder.

[0013] When the third cascaded nested cylinder is used as the adjustment object, the drainage volume of the third cascaded nested cylinder is adjusted by adjusting the position of the piston in the third cascaded nested cylinder; when the second cascaded nested cylinder is used as the adjustment object, the drainage volume of the second cascaded nested cylinder is adjusted by adjusting the position of the lower end of the third cascaded nested cylinder in the second cascaded nested cylinder; when the first cascaded nested cylinder is used as the adjustment object, the drainage volume of the first cascaded nested cylinder is adjusted by adjusting the position of the lower end of the third cascaded nested cylinder extending into the first cascaded nested cylinder.

[0014] In some embodiments, when the adjustment mode is a diving adjustment mode, the control method includes:

[0015] Obtain the set submersion and levitation depth H, and query the lookup table to determine the adjustment object that is compatible with the submersion and levitation depth;

[0016] The control motor drives the piston to move, so that the piston or the third-stage nested cylinder moves to the position corresponding to the adjustment object;

[0017] The device acquires its current depth h in real time and compares it with the suspension depth H. When h and H are consistent, the motor is turned off to maintain the current state.

[0018] In some embodiments, when the device's descent speed exceeds a preset safety threshold in the descent adjustment mode, the control motor pushes the piston outward, with an adjustment range of Δd1, to increase the device's buoyancy.

[0019] In some embodiments, when the descent speed of the device decreases within a safe threshold in the descent adjustment mode, the control motor is further included to pull the piston inward, with an adjustment range of Δd2, where Δd2 < Δd1.

[0020] In some embodiments, when the adjustment mode is an adaptive floating adjustment mode, the control method includes:

[0021] Calculate the current depth offset Δh, Δh = |hH|;

[0022] If Δh≤0.1H, maintain the current regulating object and pressure, and do not take any action;

[0023] If Δh > 0.1H and h > H, control the motor to push the piston outward, increasing the preset first drainage volume V1, continue to detect Δh, and repeat this adjustment step until Δh ≤ 0.1H;

[0024] If Δh > 0.1H and h < H, control the motor to pull back the piston, reduce the preset second drainage volume V2, continue to detect Δh, and repeat this adjustment step to fine-tune until Δh ≤ 0.1H.

[0025] In some embodiments, the method further includes the step of calculating the motor's outward stroke based on V1 and V2:

[0026] Obtain the cross-sectional area S of the inner cavity of the object being adjusted, control the stroke of the outward piston of the motor to D1=V1 / S, and control the stroke of the retracting piston of the motor to D2=V2 / S.

[0027] In some embodiments, the current ambient water pressure P is obtained, and the thrust output by the motor is controlled to be greater than P*S.

[0028] In some embodiments, the values ​​of V1 and V2 range from 0.01 to 0.5L.

[0029] In some embodiments, when the adjustment mode is a multi-tiered nested cylinder gradient upward adjustment mode, the control method includes:

[0030] Upon receiving the upward command, identify the cascaded nested cylinder currently being adjusted; if it is the third cascaded nested cylinder, control the motor to push the piston outward.

[0031] The depth of the device is acquired in real time. When the depth of the device matches the adjustment object of the second-stage nested cylinder, the motor is controlled to push the piston outward, which drives the lower end of the third-stage nested cylinder to move axially in the second-stage nested cylinder.

[0032] When the depth of the device matches the adjustment object of the first cascade nested cylinder, the control motor continues to push the piston outward, so that the lower end of the third cascade nested cylinder is inserted into the first cascade nested cylinder until the maximum stroke is reached.

[0033] Compared with existing technologies, the advantages and positive effects of this invention are as follows: The buoyancy adjustment method based on multi-cascade nested cylinders of this invention adjusts buoyancy at different underwater depths by setting three cascade nested cylinders. Specifically, by setting different inner diameters between the cascade nested cylinders, and based on the principle that external water pressure equals the product of the cross-sectional area of ​​the inner cavity of the cascade nested cylinder and the pressure, due to the high pressure in deep water, the cascade cylinder with the smaller inner diameter is selected as the adjustment target for buoyancy control in deep water. At this time, the external water pressure is low, and when the motor controls the outward piston, the thrust provided needs to be greater than the pressure, so a smaller thrust can be output to achieve buoyancy adjustment. In shallow water, the cascade cylinder with the larger inner diameter is selected as the adjustment target for buoyancy control. At this time, the external pressure is reduced, and even if the inner diameter of the adjusted cascade cylinder is large, the external water pressure will not increase or will not increase significantly after multiplying the two, so the motor still only needs to output a small thrust to achieve buoyancy adjustment. As the depth of the device decreases from deep to shallow, the buoyancy gradually increases, reaching its maximum when it rises to the surface. This ensures that the underwater mobile observation device floats to a sufficient height above the water, increasing the height of the antenna above the water and facilitating data transmission.

[0034] The underwater mobile observation device of this invention comprises multiple cascaded nested cylinders, all of which are connected to the outside environment. A motor drives a piston to move axially within the third cascaded nested cylinder via a push rod. The third cascaded nested cylinder can move axially relative to the second cascaded nested cylinder. Therefore, when the piston is at the top, all three cascaded nested cylinders are filled with water, resulting in minimal buoyancy. By driving the piston downwards, the water in the third cascaded nested cylinder is squeezed, and the squeezed water sequentially enters the second cascaded nested cylinder, then the first cascaded nested cylinder, and finally is discharged through the drainage chamber. As the water in the third cascaded nested cylinder is gradually discharged, the space above the piston becomes a sealed space, increasing the drainage volume of the underwater mobile observation device and thus increasing buoyancy. When the piston reaches the bottom of the third cascaded nested cylinder and abuts against its bottom cover, the motor pushes the piston further forward, causing the third cascaded nested cylinder to move downwards relative to the second cascaded nested cylinder. The third cascaded nested cylinder squeezes the water in the second cascaded nested cylinder, and the squeezed water enters the first cascaded nested cylinder, finally being discharged through the drainage chamber. Because the third-tier nested cylinder seals the annular gap between the second-tier nested cylinders, this process further increases the drainage volume of the underwater mobile observation device, thereby further increasing buoyancy. The motor continues to operate, allowing the lower end of the third-tier nested cylinder to pass through the lower end of the second-tier nested cylinder and penetrate into the first-tier nested cylinder. The water in the first-tier nested cylinder is squeezed and discharged through the drainage chamber. This process further increases the drainage volume of the underwater mobile observation device, further increasing buoyancy to its maximum. When the underwater mobile observation device rises to the surface, this increases the portion of the device that is above water. This ensures that the communication antenna on the device can float above the water, thus guaranteeing the stability of the antenna signal. Conversely, the above process reduces the buoyancy of the underwater mobile observation device, enabling it to perform reciprocating probes of the water profile.

[0035] The underwater mobile observation device in this solution achieves buoyancy adjustment through multiple cascaded nested cylinders, with a wide buoyancy adjustment range, which can meet the buoyancy adjustment needs of different scenarios. It is suitable for both deep-water and shallow-water observation, making it widely applicable.

[0036] Compared with traditional oil suction and discharge and buoyancy adjustment devices, this scheme does not require the installation of oil storage devices, water storage tanks, high-pressure air pumps and other devices, which helps to reduce the size of underwater mobile observation devices. Therefore, it is especially suitable for miniaturized and low-cost observation devices.

[0037] The buoyancy is adjusted by using a piston driven by a motor to pump water, which has a fast response speed and short adjustment time. It avoids the problem of continuous electromagnetic interference caused by the motor to the monitoring element and can be equipped with more precise sensors.

[0038] The displacement volume has a linear relationship with the cross-sectional area of ​​the inner cavity of the cascaded nested cylinders and the stroke of the push rod, so the buoyancy can be accurately calculated and adjusted, which is beneficial to improving the adjustment accuracy.

[0039] Other features and advantages of the present invention will become clearer after reading the detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the underwater mobile observation device in one embodiment of the control method for the underwater mobile observation device proposed in this invention;

[0041] Figure 2 yes Figure 1 A partial exploded view;

[0042] Figure 3 This is a cross-sectional view of an underwater mobile observation device in one embodiment of the control method for the underwater mobile observation device proposed in this invention;

[0043] Figure 4 This is a partially enlarged cross-sectional view of the underwater mobile observation device in one embodiment of the control method for the underwater mobile observation device proposed in this invention;

[0044] Figure 5 This is a state diagram of the third-level nested cylinder as the adjustment object in one embodiment of the underwater mobile observation device control method proposed in this invention;

[0045] Figure 6 This is a state diagram of the second cascaded nested cylinder as the adjustment object in one embodiment of the underwater mobile observation device control method proposed in this invention;

[0046] Figure 7 This is a state diagram of the first cascaded nested cylinder as the adjustment object in one embodiment of the underwater mobile observation device control method proposed in this invention;

[0047] Figure 8 This is a state diagram showing the maximum drainage volume in one embodiment of the underwater mobile observation device control method proposed in this invention;

[0048] Figure 9 This is a cross-sectional view of an embodiment of the underwater mobile observation platform based on buoyancy adjustment of multi-level nested cylinders proposed in this invention;

[0049] Figure 10 This is a flowchart of an embodiment of the control method for an underwater mobile observation device proposed in this invention;

[0050] Among them, 10, outer shell; 101, motor compartment; 102, drainage compartment; 103, first drainage hole; 104, electrical compartment; 11, first cascaded nested cylinder; 12, second cascaded nested cylinder; 13, third cascaded nested cylinder; 131, top cover; 132, bottom cover; 133, connecting port; 134, sealing ring; 14, motor; 141, push rod; 15, piston; 151, protrusion; 16, sealing structure; 17, bracket; 171, support column; 172, ring beam; 18, upper top plate; 19, ring support platform; 20, communication antenna. Detailed Implementation

[0051] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] It should be noted that in the description of this invention, terms such as "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] Example 1: This example proposes a buoyancy adjustment method based on multi-tiered nested cylinders. In this example, [the method is described in the original text]. Figures 1-3The underwater mobile observation device with multiple cascaded nested cylinders is illustrated as an example. This underwater mobile observation device includes multiple cascaded nested cylinders. In this embodiment, three cascaded nested cylinders are used: a first cascaded nested cylinder 11, a second cascaded nested cylinder 12, and a third cascaded nested cylinder 13. A piston 15 is installed in the third cascaded nested cylinder 13. The inner diameter of the third cascaded nested cylinder 13 is smaller than that of the first cascaded nested cylinder 11 and the second cascaded nested cylinder 12. The motor 14 pushes or pulls the piston 15 axially via a push rod. At different underwater depths, the underwater mobile observation device adjusts buoyancy using different cascaded nested cylinders. In shallow water, a cascaded cylinder with a larger inner diameter is selected for buoyancy control, while in deep water, a cascaded cylinder with a smaller inner diameter is selected for buoyancy control.

[0056] like Figure 10 As shown, this buoyancy adjustment method includes:

[0057] (1) Generate a lookup table for the depth adjustment range corresponding to each level of nested cylinder when they are used as adjustment objects, and store it in the storage module.

[0058] Each cascaded cylinder can be used individually for buoyancy adjustment. The optimal depth adjustment range for each nested cylinder can be pre-calculated or measured in the laboratory, and a lookup table can be created based on this correspondence. The lookup table can be stored in the storage module of the underwater mobile observation device so that the control module can read it.

[0059] In this embodiment, the preferred depth adjustment range refers to the following: based on the formula relating pressure, stress, and cross-sectional area, the cross-sectional area of ​​the inner cavity of the cascaded nested cylinder is matched with the pressure corresponding to the depth, so that the relatively low thrust output of the motor 14 can counteract the external water pressure acting on the cascaded nested cylinder to adjust buoyancy, thereby saving the power consumption of the motor 14.

[0060] (2) Identify the current adjustment mode, obtain the current depth h of the device, determine the cascaded nested cylinder as the adjustment object based on the current depth h, and control the motor 14 to drive the piston 15 to move in combination with the adjustment mode, adjust the drainage volume of the cascaded nested cylinder as the adjustment object, and realize the buoyancy adjustment of the device.

[0061] According to the buoyancy formula, the buoyancy of the device is related to its displacement volume. This scheme aims to change the buoyancy of the underwater mobile observation device by adjusting the displacement volume of each stage of the nested cylinder.

[0062] The zero-buoyancy position of the underwater mobile observation device can be freely set, such as within the third-level nested cylinder 13 with the smallest internal cross-sectional area. The length of this cylinder can be slightly longer to facilitate fine-tuning of the buoyancy of the underwater mobile observation device near the suspension depth.

[0063] In this embodiment, the zero buoyancy balance position can be set in the cascaded nested cylinder with the smallest cross-sectional area (the third cascaded nested cylinder in this embodiment). That is, the chamber length of the cascaded nested cylinder is relatively long, which is more suitable for fine-tuning and precise depth setting. When floating on the water surface, in order to facilitate detection and data transmission, the positive buoyancy adjustment range can be set to be much larger than the negative buoyancy adjustment range, which is more convenient for underwater motion attitude control.

[0064] The adjustment modes include diving adjustment mode, adaptive suspension adjustment mode, and multi-level nested cylinder gradient buoyancy adjustment mode.

[0065] In this embodiment, the number of cascaded nested cylinders can be expanded to four or more.

[0066] The inner diameters of these multiple cascaded nested cylinders can increase sequentially. For two adjacent cascaded nested cylinders, the inner diameter of the lower cascaded nested cylinder is the same as the outer diameter of the upper cascaded nested cylinder, achieving a sealed nesting. Piston 15 is located inside the cascaded nested cylinder with the smallest inner diameter. Piston 15 can move axially within this cascaded nested cylinder, achieving water pumping and buoyancy adjustment. When piston 15 moves to the bottom of the cascaded nested cylinder with the smallest inner diameter, it can further drive the entire cascaded nested cylinder with the smallest inner diameter to move axially within its nested cascaded nested cylinders, achieving water pumping and buoyancy adjustment, and so on. Because the inner diameters of these multiple cascaded nested cylinders are different, their cross-sectional areas are also different. According to the formula pressure = pressure intensity × cross-sectional area, the motor thrust is used to overcome external water pressure. Therefore, when acting on different cascaded nested cylinders, due to the different cross-sectional areas, at the same pressure, the larger the cross-sectional area, the smaller the thrust. By controlling the pumping and buoyancy in different cascaded nested cylinders, the thrust can be adjusted. For different pressure environments (corresponding to different water depths), this solution can also control the pumping of water in different cascaded nested cylinders (e.g., when the pressure is high, pumping water is done by pumping water from the cascaded nested cylinders with smaller inner diameters, and when the pressure is low, pumping water is done by pumping water from the cascaded nested cylinders with larger inner diameters). This allows the output thrust to increase in a non-proportional manner with the pressure. Different depths are matched with cascaded nested cylinders with different cross-sections and pressure regulation. Deep-sea drainage does not require excessive pressurization, and shallow-sea drainage avoids excessive external pressure. That is, it adopts adaptive adjustment of force based on water depth and pressure gradient, which is more efficient than constant external pressure adjustment.

[0067] The inner diameters of these multiple cascaded nested cylinders may differ in some cases. The cascaded nested cylinder with the smallest inner diameter is movable, while the others are fixed. Piston 15 is positioned inside the cascaded nested cylinder with the smallest inner diameter. The outer diameter of this cylinder is consistent with the inner diameters of the other cascaded nested cylinders. Piston 15 can move axially within this cascaded nested cylinder, thereby pumping water out of it and adjusting buoyancy. When piston 15 reaches the bottom of the cascaded nested cylinder with the smallest inner diameter, it can further drive the entire cascaded nested cylinder with the smallest inner diameter to move axially within its nested cascaded nested cylinders, thereby pumping water out of it and further adjusting buoyancy. This cascaded nested cylinder with the smallest inner diameter can then be pushed outwards into the next cascaded nested cylinder, achieving the same pumping action. Since the inner diameters of the multiple cascaded nested cylinders may not be exactly the same, their cross-sectional areas will also be different. This solution can still achieve cascaded nested cylinders with different cross-sections and pressure regulation at different depths. Deep-sea drainage does not require excessive pressurization, and shallow-sea drainage avoids excessive external pressure. That is, it uses adaptive adjustment based on water depth and pressure gradient, which is more efficient than constant external pressure regulation.

[0068] The buoyancy control method of the underwater mobile observation device in this embodiment uses three cascaded nested cylinders to adjust buoyancy at different depths. Specifically, by setting different inner diameters among the cascaded nested cylinders, and based on the principle that external water pressure equals the product of the cross-sectional area of ​​the inner cavity of the cascaded nested cylinder and the pressure, the smaller inner diameter cascaded cylinder is selected for buoyancy control in deep water due to the higher pressure. In this case, the external water pressure is low, and when the motor 14 controls the outward-pushing piston 15, the thrust provided needs to be greater than the pressure. Because the external water pressure is low, the output thrust does not need to be too large to achieve buoyancy adjustment. In shallow water, a larger inner diameter cascaded cylinder is selected for buoyancy control. In this case, the external pressure is reduced, and even if the inner diameter of the adjusted cascaded cylinder is large, the external water pressure will not increase significantly after multiplying the two. Therefore, the motor 14 only needs to output a small thrust to achieve buoyancy adjustment. As the depth of the underwater mobile observation device decreases from deep to shallow, the buoyancy gradually increases, reaching its maximum when it rises to the surface. This ensures that the underwater mobile observation device floats to a sufficient height above the water, increasing the height of the antenna above the water, thus facilitating data transmission.

[0069] In some embodiments, the lower end of the third cascaded nested cylinder 13 extends into the second cascaded nested cylinder 12 and can move axially relative to the second cascaded nested cylinder 12. The first cascaded nested cylinder 11 is located below the second cascaded nested cylinder 12. When the motor 14 pushes the piston 15 outward through the push rod, the piston 15 moves towards the bottom of the third cascaded nested cylinder 13 in the third cascaded nested cylinder 13. After abutting the bottom of the third cascaded nested cylinder 13, it can drive the third cascaded nested cylinder 13 to move downward relative to the second cascaded nested cylinder 12 until the lower end of the third cascaded nested cylinder 13 passes through the lower end of the second cascaded nested cylinder 12 and extends into the first cascaded nested cylinder 11, moving axially relative to the first cascaded nested cylinder 11.

[0070] When the third-level nested cylinder 13 is used as the regulating object, such as Figure 5 As shown, the position of piston 15 within the third-stage nested cylinder 13 is adjusted to regulate the drainage volume of the third-stage nested cylinder 13; when the second-stage nested cylinder 12 is the object of adjustment, as... Figure 6 As shown, by adjusting the position of the lower end of the third cascaded nested cylinder 13 within the second cascaded nested cylinder 12, the drainage volume of the second cascaded nested cylinder 12 is adjusted; when the first cascaded nested cylinder 11 is the object of adjustment, as... Figure 7 As shown, the drainage volume of the first cascaded nested cylinder 11 is adjusted by adjusting the position of the lower end of the third cascaded nested cylinder 13 protruding into the first cascaded nested cylinder 11.

[0071] Specifically, such as Figure 3 , Figure 4 As shown, the second cascaded nested cylinder 12 has open ends. The second cascaded nested cylinder 12 is fixedly installed inside the outer shell 10, located between the motor compartment 101 and the drainage compartment 102. The outer side of the second cascaded nested cylinder 12 is sealed to the outer shell 10.

[0072] The motor 14 is housed in the motor compartment 101, which is located at one end of the outer casing 10. The motor shaft of the motor 14 is located in the direction of the central axis of the outer casing 10 and faces the other end of the outer casing 10.

[0073] The lower end of the third-level nested cylinder 13 extends into the second-level nested cylinder 12 and can move axially relative to the second-level nested cylinder 12. A sealing structure 16 is provided between the third-level nested cylinder 13 and the second-level nested cylinder 12 to seal the annular gap between them. A communication port 133 is provided on the bottom cover 132 of the third-level nested cylinder 13.

[0074] Piston 15 is disposed within the third-tier nested cylinder 13 and can move axially relative to the third-tier nested cylinder 13. The outer wall of piston 15 is tightly fitted with the inner surface of the third-tier nested cylinder 13, sealing the two together. The motor shaft of motor 14 passes through the top cover 131 of the third-tier nested cylinder 13 and is fixedly connected to piston 15. Motor 14 outputs power, driving piston 15 to move axially via motor shaft. Because piston 15 and the third-tier nested cylinder 13 are sealed, piston 15 divides the third-tier nested cylinder 13 into two spaces. The space below piston 15 communicates with the second-tier nested cylinder 12 and is connected to the outside of outer casing 10 through the second drain hole and the first drain hole 103. That is, when the device is underwater, this space is filled with water. The space above piston 15 communicates with motor compartment 101 and is sealed and isolated from the external space, achieving a water-sealed state. The motor 14 drives the piston 15 to move, which can change the volume of the water-sealed space, that is, the drainage volume, thereby adjusting the buoyancy of the device.

[0075] The first cascaded nested cylinder 11 is fixedly installed in the drainage chamber 102 and is coaxially arranged with the first cascaded nested cylinder 11 and the second cascaded nested cylinder 12. The top of the first cascaded nested cylinder 11 is open, and the inner diameter of the first cascaded nested cylinder 11 is not less than the outer diameter of the third cascaded nested cylinder 13. When the motor shaft 14 drives the third cascaded nested cylinder 13 to move downward through the piston 15, the lower end of the third cascaded nested cylinder 13 can pass through the lower end of the second cascaded nested cylinder 12 and enter the first cascaded nested cylinder 11. The first cascaded nested cylinder 11 is provided with a second drainage hole that communicates with the drainage chamber 102.

[0076] The working principle of the underwater mobile observation device in this embodiment is as follows:

[0077] (1) By setting up three cascaded nested cylinders and a drainage chamber 102, all three cascaded nested cylinders are connected to the drainage chamber 102. The motor 14 can drive the piston 15 to move axially in the third cascaded nested cylinder 13 through the push rod. The third cascaded nested cylinder 13 can move axially relative to the second cascaded nested cylinder 12. Therefore, when the piston 15 is at the top, all three cascaded nested cylinders are filled with water. At this time, the buoyancy is minimal, which is suitable for scenarios where underwater mobile observation devices need to sink quickly.

[0078] (2) By driving piston 15 downward, the water in the third-level nested cylinder 13 is squeezed. The squeezed water enters the second-level nested cylinder 12 and the first-level nested cylinder 11 in sequence, and is finally discharged through the drainage chamber 102. As the water in the third-level nested cylinder 13 is gradually discharged, the space above piston 15 becomes a sealed space, thereby increasing the drainage volume of the underwater mobile observation device and thus increasing buoyancy. When piston 15 moves to the bottom of the third-level nested cylinder 13, it abuts against the bottom cover 132 of the third-level nested cylinder 13. Motor 14 pushes piston 15 forward, which can drive the third-level nested cylinder 13 to move downward relative to the second-level nested cylinder 12. The third-level nested cylinder 13 squeezes the water in the second-level nested cylinder 12. The squeezed water enters the first-level nested cylinder 11 and is finally discharged through the drainage chamber 102. Since the annular gap between the second-level nested cylinder 12 is sealed by the third-level nested cylinder 13, this process can further increase the drainage volume of the underwater mobile observation device and thus further increase buoyancy.

[0079] (3) The motor 14 continues to operate, and the lower end of the third-level nested cylinder 13 can pass through the lower end of the second-level nested cylinder 12 and enter the first-level nested cylinder 11. The water in the first-level nested cylinder 11 is squeezed and discharged through the drainage chamber 102. This process further increases the drainage volume of the underwater mobile observation device, thereby further increasing the buoyancy. At this time, the buoyancy is at its maximum, and when the underwater mobile observation device rises to the surface, it can increase the portion of the underwater mobile observation device that is above the water. This ensures that the communication antenna installed on the device can float above the water, thereby ensuring the stability of the antenna signal.

[0080] Table 1: Lookup table for 3 cascaded nested cylinders

[0081] cabin Adapted depth range Inner cavity cross-sectional area / radius Cabin length Extrapolated minimum thrust First-stage nested cylinder 0-100m 0.01m² / 0.057m 0.1m 1000kg Second-stage nested cylinder 100-200m 0.005m / 0.04m 0.2m 1000kg Third-stage nested cylinder 200-400m 0.0025m / 0.028m 0.4m 1000kg

[0082] In some embodiments, it also includes simultaneously preset: the suspension depth offset threshold setting depth ±10%, and the seawater volume for a single fine adjustment of 0.02L.

[0083] In some embodiments, when the adjustment mode is a diving adjustment mode, the control method includes:

[0084] Obtain the set submersion and levitation depth H, and query the lookup table to determine the adjustment object that is compatible with this submersion and levitation depth.

[0085] Specifically, if H∈[0,100m], the first cascaded nested cylinder 11 is selected as the adjustment object; if H∈(100m,200m], the second cascaded nested cylinder 12 is selected as the adjustment object; if H∈(200m,400m], the third cascaded nested cylinder 13 is selected as the adjustment object.

[0086] The control motor 14 drives the piston 15 to move, so that the piston 15 or the third-stage nested cylinder 13 moves to the position corresponding to the object to be adjusted.

[0087] Specifically, when the object of adjustment is the third cascaded nested cylinder 13, the piston 15 is located in the third cascaded nested cylinder 13 but not touching the bottom of the third cascaded nested cylinder 13. By adjusting the position of the piston 15 in the third cascaded nested cylinder 13, the drainage volume of the third cascaded nested cylinder 13 can be adjusted. When the object of adjustment is the second cascaded nested cylinder 12, by adjusting the lower end of the third cascaded nested cylinder 13 in the second cascaded nested cylinder 12, its position in the second cascaded nested cylinder 12 can be adjusted, thus adjusting the drainage volume of the first cascaded nested cylinder 11. When the object of adjustment is the first cascaded nested cylinder 11, by adjusting the lower end of the third cascaded nested cylinder 13 to extend into the first cascaded nested cylinder 11, its position in the first cascaded nested cylinder 11 can be adjusted, thus adjusting the drainage volume of the first cascaded nested cylinder 11.

[0088] The current depth h of the underwater mobile observation device is acquired in real time and compared with the suspension depth H. When h matches H, motor 14 is shut down to maintain the current state. The push rod motor has a holding function, which can maintain the current thrust after shutdown.

[0089] In some embodiments, when the diving speed of the underwater mobile observation device exceeds a preset safety threshold (such as, but not limited to, 0.4 m / s), the diving adjustment mode also includes controlling the motor 14 to push the piston 15 outward, adjusting the range by Δd1 to increase the buoyancy of the underwater mobile observation device.

[0090] This step can be achieved by controlling motor 14 to push out the motor 14 shaft for 4s-20s, coarsely adjusting the buoyancy to reduce the speed, and then dynamically adjusting the pushing and pulling action of push rod 141.

[0091] In some embodiments, when the diving speed of the underwater mobile observation device decreases within a safe threshold in the diving adjustment mode, the control motor 14 pulls the piston 15 inward, and the adjustment range is △d2, △d2 < △d1, so as to stabilize the diving attitude of the underwater mobile observation device.

[0092] In some embodiments, when the adjustment mode is an adaptive floating adjustment mode, the control method includes:

[0093] Calculate the current depth offset Δh, Δh = |hH|.

[0094] If Δh≤0.1H, maintain the current regulating object and pressure, and do not take any action.

[0095] If Δh > 0.1H and h > H (depth is too large), control motor 14 to push piston 15 outward to increase the preset first drainage volume V1, continue to detect Δh, and repeat this adjustment step until Δh ≤ 0.1H.

[0096] If Δh > 0.1H and h < H (depth is too small), control motor 14 to pull back piston 15, reduce the preset second drainage volume V2, continue to detect Δh, and repeat this adjustment step to fine-tune until Δh ≤ 0.1H.

[0097] This solution enables precise depth control through the aforementioned buoyancy adjustment.

[0098] In some embodiments, the method further includes the step of calculating the extra stroke of motor 14 based on V1 and V2:

[0099] Obtain the cross-sectional area S of the inner cavity of the object being adjusted, control the stroke D1=V1 / S of the piston 15 pushed outward by the motor 14, and control the stroke D2=V2 / S of the piston 15 pulled back by the motor 14.

[0100] The drainage volume has a linear relationship with the cross-sectional area of ​​the inner cavity of the cascaded nested cylinders and the stroke of the 14th shaft of the motor. Therefore, the buoyancy can be accurately calculated and adjusted, which is beneficial to improving the adjustment accuracy.

[0101] In some embodiments, the current ambient water pressure P is obtained, and the thrust output of the motor 14 is controlled to be greater than P*S, so as to ensure that the motor 14 can overcome the external water pressure and push outward.

[0102] In some embodiments, the values ​​of V1 and V2 range from 0.01 to 0.5L.

[0103] In some embodiments, when the adjustment mode is a multi-tiered nested cylinder gradient upward adjustment mode, the control method includes:

[0104] Upon receiving the surfacing command, the system identifies the cascaded nested cylinder currently being regulated. If it is the third cascaded nested cylinder 13, the system controls the motor 14 to push the piston 15 outward, discharging the seawater from the third cascaded nested cylinder 13. After the water in the chamber is discharged, a small buoyancy is generated, initiating the surfacing of the underwater mobile observation device.

[0105] The depth of the underwater mobile observation device is acquired in real time. When the depth of the underwater mobile observation device matches the adjustment object of the second-stage nested cylinder 12, the control motor 14 pushes the piston 15 outward, driving the lower end of the third-stage nested cylinder 13 to move axially in the second-stage nested cylinder 12.

[0106] During the ascent of the underwater mobile observation device, when the monitoring depth reaches the depth range of the second-level nested cylinder 12, the control motor 14 continues to push outward. The same thrust acts on the second-level nested cylinder 12 with a slightly larger cross-sectional area, generating a matching pressure to counteract the local water pressure, which facilitates the discharge of water from the second-level nested cylinder 12, thereby quickly increasing the overall buoyancy and enabling the underwater mobile observation device to rise rapidly.

[0107] When the depth of the underwater mobile observation device matches the adjustment object of the first cascade nested cylinder 11, the control motor 14 continues to push the piston 15 outward, so that the lower end of the adjustment third cascade nested cylinder 13 is inserted into the first cascade nested cylinder 11 until it is pushed to the maximum stroke.

[0108] When the underwater mobile observation device reaches or approaches the water surface, the external water pressure is low enough. The control motor 14 pushes the cascaded nested cylinders outward to the third push-out first cascaded nested cylinder 11, emptying the water in all the cascaded nested cylinders, providing maximum buoyancy, and allowing the underwater mobile observation device to float above the water surface at a sufficient height, increasing the height of the antenna above the water surface, thus facilitating data transmission.

[0109] The underwater mobile observation device descends in the opposite direction to its surfacing process. The control motor 14 pulls back the push rod 141. Under the combined action of the pulling force and the external water pressure, the three cascaded nested cylinders can stably and quickly take in water, reducing the total buoyancy of the underwater mobile observation device. When the underwater mobile observation device descends to a depth close to the set depth, it can achieve more precise suspension by adjusting the space of the third cascaded nested cylinder 13.

[0110] The method of this invention has a simple structural design and uses a push rod motor to achieve multi-depth adaptive nonlinear buoyancy adjustment. It has a large dynamic range of buoyancy adjustment, low power consumption, and is suitable for frequent reciprocating observation in shallow water. Because the buoyancy adjustment time of this method is short, it can be equipped with more precise sensors.

[0111] Example 2: Based on the underwater mobile observation device control method described in Example 1, and in conjunction with the lookup table shown in Table 1, the following specific experimental example is proposed:

[0112] A DC pusher motor with a thrust of 1200 kg is selected (due to the maximum external pressure of 1000 kg for each cascaded nested cylinder, redundant thrust is retained), with a total stroke of 0.7 m. Three cascaded nested cylinders are set, each with a volume of 1 L. The zero-buoyancy point of the platform is set at the point where the first cascaded nested cylinder 11 is fully extended, the second cascaded nested cylinder 12 is fully extended, and the third cascaded nested cylinder 13 is extended halfway. (This position can be manually set; considering that the third cascaded nested cylinder 13 has a small cross-section and long length, it is easy to adjust the buoyancy). That is, the total adjustable buoyancy is 3 kg (3 L for the three cascaded nested cylinders), the buoyancy is 2.5 kg, and the negative buoyancy is 0.5 kg.

[0113] For monitoring emergencies such as underwater internal waves and submarine earthquakes, it can quickly surface and issue an early warning after detecting such information.

[0114] The power-driven structure is simple and reliable: based on the nonlinear suction and drainage core buoyancy adjustment method, the mechanical structure is simple, highly reliable, highly compatible, and can achieve more than three levels of cascading nesting, with strong scalability.

[0115] Experimental Example 1: The diving and suspension depth H is 300m.

[0116] H=300m∈(200m,400m], starting from the water surface h=0m, the device descends. Motor 14 pulls back the push rod. Under the action of external water pressure, the third-level nested cylinder 13 is pulled back to completely exit the first-level nested cylinder 11, reducing the buoyancy of the underwater mobile observation device.

[0117] Continue pulling back the third cascaded nested cylinder 13 to exit the second cascaded nested cylinder 12 until it is completely exited from the second cascaded nested cylinder 12.

[0118] The pullback piston 15 is positioned approximately half the length of the hydraulic shaft of the third-stage nested cylinder 13 (this position can be adjusted according to the absolute buoyancy during ascent and descent). At this point, the buoyancy of the underwater mobile observation device is 0. Continuing to pull back piston 15, the underwater mobile observation device experiences negative buoyancy and begins to descend. The descent speed of the platform is monitored. During the descent from 0m to 280m, the buoyancy and descent speed are adjusted to ensure that the descent speed is ≤0.4m / s.

[0119] When h=280m, the control motor 14 pushes outward, and through the position adjustment of the long-stroke third-stage nested cylinder 13, the total buoyancy of the observation system is changed to 0 with a positive bias, reducing the descent speed. Under the action of inertia, h approaches 300m. At this depth, the buoyancy is controlled by adjusting the push rod motor's extension and retraction to match the detected depth, thus putting the underwater mobile observation device into a suspended state.

[0120] Case 2: When suspended at 300m, the depth shifts to 330m (Δh=30m).

[0121] With P=3MPa, the control module adjusts the buoyancy sign and magnitude by adjusting the extension and retraction of motor 14 and the 0.4m stroke range of the hydraulic shaft of the third-stage nested cylinder 13 at this depth. This is matched with the depth sensor to ensure that Δh≤30m. The underwater mobile observation device operates within the range of 270m-330m, with power-saving control and no fine-tuning required.

[0122] Case 3: Rising from 300m to the surface.

[0123] The suspension state is such that the first cascade nested cylinder 11 and the second cascade nested cylinder 12 are in a 0-discharge state, and the third cascade nested cylinder 13 is in a semi-discharge state. In order to make the underwater mobile observation device float, the control motor 14 pushes out the piston 15.

[0124] After the water in the third-level nested cylinder 13 is completely drained, there is already 0.5 kg of buoyancy, which is sufficient to provide buoyancy for the underwater mobile observation device to float.

[0125] When the underwater mobile observation device rises to a depth of 200m, in order to increase the buoyancy, the piston 15 is pushed to move the second-stage nested cylinder 12, which increases the buoyancy by 0.5kg, for a total buoyancy of 1kg.

[0126] The observation system reached the water surface under the influence of 1 kg of buoyancy.

[0127] 1 kg of buoyancy is insufficient to raise the underwater mobile observation device to a sufficient height. The control pusher motor continues to push outward, discharging all the water from the three cascaded nested cylinders, reaching the device's maximum buoyancy (2.5 kg). This allows the underwater mobile observation device to float to a sufficient height above the water surface, making it easier to be detected or transmit data.

[0128] Example 3: This example proposes an underwater mobile observation device based on suction and displacement buoyancy adjustment. See [link to example]. Figure 1 As shown, it includes a housing 10, a first cascaded nested cylinder 11, a second cascaded nested cylinder 12, a third cascaded nested cylinder 13, a motor 14, and a piston 15.

[0129] In this embodiment, the example is taken where the drainage tank 102 is located below the motor compartment 101 during normal operation of the underwater mobile observation device. Of course, the directions of the two can be reversed without affecting the implementation of this device.

[0130] The outer shell 10 has an axially arranged motor compartment 101 and a drainage compartment 102, and the side wall of the drainage compartment 102 is provided with a number of first drainage holes 103 that penetrate the inside and outside of the drainage compartment 102.

[0131] The underwater mobile observation device in this embodiment achieves buoyancy adjustment through multiple cascaded nested cylinders. The buoyancy adjustment range is wide, which can meet the buoyancy adjustment requirements of different scenarios. It is suitable for both deep-water and shallow-water observations, making it widely applicable.

[0132] Compared with traditional oil suction and discharge and buoyancy adjustment devices, this embodiment does not require the installation of oil storage devices, water storage tanks, high-pressure air pumps, etc., which helps to reduce the size of the underwater mobile observation device. Therefore, it is particularly suitable for miniaturized and low-cost observation devices.

[0133] The piston 15 is driven by motor 14 to adjust buoyancy by suction and drainage. The response speed is fast and the adjustment time is short. It avoids the problem of continuous electromagnetic interference caused by motor 14 to monitoring elements and can be equipped with more precise sensors.

[0134] The drainage volume has a linear relationship with the cross-sectional area of ​​the inner cavity of the cascaded nested cylinders and the stroke of the 14th shaft of the motor. Therefore, the buoyancy can be accurately calculated and adjusted, which is beneficial to improving the adjustment accuracy.

[0135] In some embodiments, the number of cascaded nested cylinders can be further expanded to more than three, thereby further increasing the buoyancy adjustment range.

[0136] After the underwater mobile observation device of this embodiment is deployed into the water, the control motor 14 retracts the push rod, and the piston 15 moves to the uppermost position of the third-stage nested cylinder 13. At this point, the drainage volume is minimized, and the device quickly submerges. The device can be equipped with a sensor for detecting water depth. When the submersion approaches a preset water depth, the control motor 14 discharges a portion of the water from the third-stage nested cylinder 13, allowing the underwater mobile observation device to float.

[0137] The figure shows the different working states of this underwater mobile observation device, demonstrating the process of "deep-water suspension → staged chamber dewatering → maximum ascent".

[0138] State 1: such as Figure 5 As shown, when the underwater mobile observation device is suspended in deep water, the control motor 14 drives the piston to keep the third-tier nested cylinder 13 in a semi-empty state, facilitating fine-tuning of buoyancy. Specifically, when the current depth is slightly deeper than the set suspension depth, the push rod 141 pushes outward, increasing the cavity of the third-tier nested cylinder 13 and improving overall buoyancy, causing the platform to rise. If the current depth is slightly shallower than the set suspension depth, the push rod 141 pulls back, decreasing the cavity of the third-tier nested cylinder 13 and reducing overall buoyancy, causing the platform to submerge. This method of fine-tuning buoyancy allows the underwater mobile observation device to remain stably suspended at the set water depth.

[0139] State 2: such as Figure 6 As shown, all the water in the third-level nested cylinder 13 is discharged, and the underwater mobile observation device is in the process of rising from deep water. In this state, because the overall cavity volume of the third-level nested cylinder 13 is limited, the buoyancy generated after all the water is discharged is not high. It only makes the buoyancy of the underwater mobile observation device greater than zero, and it can slowly rise. After reaching the depth that the second-level nested cylinder 12 can push, the motor 14 mechanically pushes the push rod outward to start discharging the water in the second-level nested cylinder 12.

[0140] State 3: such as Figure 7As shown, after the push rod 141 empties the water in the second-stage nested cylinder 12, the added buoyancy is the total buoyancy of all the cavities of the second-stage nested cylinder 12 and half of the cavities of the first-stage nested cylinder 11. At this time, the total buoyancy can make the underwater mobile observation device quickly float to the surface of the water.

[0141] State 4: such as Figure 8 As shown, the observation system has reached the water surface. Push rod 141 continues to push outward, emptying the water in the first cascaded nested cylinder 11, and then continues to push outward the entire cabin to further increase the drainage volume. Under the total buoyancy of the three cascaded nested cylinders, the underwater mobile observation device will float to the surface with maximum buoyancy.

[0142] In some embodiments, motor 14 may be implemented using, but is not limited to, a push rod motor.

[0143] To improve the integration of this device and facilitate the assembly and fixing of the motor 14, in some embodiments, the lower end of the second-stage nested cylinder 12 is sealed and fixed to the inner wall of the outer casing 10, and a bracket 17 and an upper top plate 18 are also provided inside the motor compartment 101.

[0144] The bracket 17 is fixed to the upper end of the second-stage nested cylinder 12 and extends upward from the upper end of the second-stage nested cylinder 12. The upper top plate 18 is fixed to the upper end of the bracket 17. The motor 14 is fixed to the bottom wall of the upper top plate 18.

[0145] In some embodiments, the bracket 17 includes a plurality of support columns 171 extending along the axis of the housing 10 and annular beams 172 that sequentially fix each support column 171. There are one or more annular beams 172. By combining and fixing a plurality of support columns 171 and annular beams 172, stable support can be provided for the motor 14 without adding too much weight to the device, thus reducing the weight of the device.

[0146] The lower surface of piston 15 can be a plane. When the motor 14 shaft drives piston 15 to move downward to the bottom of the third-stage nested cylinder 13, the lower surface of piston 15 abuts against the bottom cover 132 of the third-stage nested cylinder 13, and at the same time can block the connecting port 133. The motor 14 continues to output, and piston 15 can drive the third-stage nested cylinder 13 to move axially relative to the second-stage nested cylinder 12. The direction of movement is towards the first-stage nested cylinder 11, thus squeezing the water in the second-stage nested cylinder 12 and discharging it through the first-stage nested cylinder 11 and the drainage chamber 102 in sequence.

[0147] In some embodiments, to improve the sealing capability of piston 15, such as... Figure 3 , Figure 4As shown, the lower end of the piston 15 has a protrusion 151 that matches the connecting port 133. When the motor 14 shaft drives the piston 15 downward to the bottom of the third-stage nested cylinder 13, the protrusion 151 is inserted into the connecting port 133. The edge of the lower surface of the piston 15 around the protrusion 151 overlaps the bottom cover 132 of the third-stage nested cylinder 13, thereby driving the third-stage nested cylinder 13 to move relative to the second-stage nested cylinder 12 towards the first-stage nested cylinder 11. Water in the second-stage nested cylinder 12 is discharged through the first drain hole 103. By providing the protrusion 151, when the piston 15 contacts the bottom of the third-stage nested cylinder 13, the protrusion 151 can tightly seal the connecting port 133, preventing water from the lower space from entering the space above the piston 15.

[0148] The bottom of the second-tier nested cylinder 12 is open. After the third-tier nested cylinder 13 moves to the bottom of the second-tier nested cylinder 12, it can pass through the bottom of the second-tier nested cylinder 12 and continue moving into the first-tier nested cylinder 11. To solve the problem of water leakage due to poor sealing performance when the third-tier nested cylinder 13 transitions from the second-tier nested cylinder 12 to the first-tier nested cylinder 11, in some embodiments, the sealing structure 16 is fixedly installed at the upper end of the second-tier nested cylinder 12 and protrudes from the inner surface of the sealing structure 16. With this configuration, regardless of which nested cylinder the lower end of the third-tier nested cylinder 13 extends into, the gap between the third-tier nested cylinder 13 and the second-tier nested cylinder 12 can always remain sealed.

[0149] To further improve the sealing performance between the third-level nested cylinder 13 and the second-level nested cylinder 12, and to ensure a seal between the third-level nested cylinder 13 and the inner wall of the first-level nested cylinder 11 when the third-level nested cylinder 13 is inserted into the first-level nested cylinder 11, in some embodiments, one or more sealing rings 134 are provided around the outer side of the lower end of the third-level nested cylinder 13. When the lower end of the third-level nested cylinder 13 is located in the second-level nested cylinder 12, the third-level nested cylinder 13 and the second-level nested cylinder 12 can be sealed at multiple locations by the sealing structure 16 and the sealing rings 134. When the lower end of the third-level nested cylinder 13 is inserted into the first-level nested cylinder 11, the third-level nested cylinder 13 and the second-level nested cylinder 12 can be sealed by the sealing structure 16, and the third-level nested cylinder 13 and the first-level nested cylinder 11 can be sealed by the sealing rings 134. The sealing scheme in this embodiment can solve the sealing problem under different conditions.

[0150] In some embodiments, a sealed electrical compartment 104 is also formed inside the outer casing 10, located below the drainage compartment 102. The electrical compartment 104 can house electronic devices such as batteries and control boards to provide power to the various onboard detection elements and to perform control and data transmission.

[0151] To prevent the third-level nested cylinder 13 from affecting the drainage efficiency of the second drain hole when it enters the first-level nested cylinder 11, in some embodiments, the second drain hole is located at the bottom or lower end of the side wall of the first-level nested cylinder 11. This avoids the movement path of the third-level nested cylinder 13, maintains high drainage efficiency, and thus ensures the buoyancy adjustment efficiency of the device. Figure 9 As shown, in this embodiment, the second drain hole is located at the bottom of the first cascaded nested cylinder 11.

[0152] To ensure the sealing performance of the transition area between the lower end of the second-tier nested cylinder 12 and the first-tier nested cylinder 11, in some embodiments, an annular support platform 19 is provided between the second-tier nested cylinder 12 and the drainage chamber 102, with the lower end of the second-tier nested cylinder 12 sealed and fixed to the annular support platform 19. The upper end of the first-tier nested cylinder 11 is fixed to the annular support platform 19. By providing the annular support platform 19, the function of simultaneously supporting the second-tier nested cylinder 12 and the first-tier nested cylinder 11 is achieved. Moreover, the annular support platform 19 can provide a sealed transition connection between the second-tier nested cylinder 12 and the first-tier nested cylinder 11, which is beneficial to the smoothness of the movement of the third-tier nested cylinder 13 from the second-tier nested cylinder 12 to the first-tier nested cylinder 11, and also prevents water leakage from the third-tier nested cylinder 13 between the second-tier nested cylinder 12.

[0153] In some embodiments, the top of the outer shell 10 is also provided with a communication antenna for communicating with satellites when it floats on the water, so as to send the collected data to a shore-based or ship-based receiving device.

[0154] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A buoyancy adjustment method based on multi-tiered nested cylinders, characterized in that, The multi-tiered nested cylinder includes a first-tier nested cylinder, a second-tier nested cylinder, and a third-tier nested cylinder. A piston is installed in the third-tier nested cylinder. The inner diameter of the third-tier nested cylinder is smaller than that of the first-tier nested cylinder and the second-tier nested cylinder. The motor pushes or pulls the piston axially through the motor rod. When the device is at different depths underwater, buoyancy is adjusted by different tiered nested cylinders. In shallow water, the tiered cylinder with a larger inner diameter is selected as the adjustment object for buoyancy control, while in deep water, the tiered cylinder with a smaller inner diameter is selected as the adjustment object for buoyancy control. The buoyancy adjustment method includes: (1) Generate a lookup table for the depth adjustment range corresponding to each level of nested cylinder when they are used as adjustment objects and store it in the storage module; (2) Identify the current adjustment mode, obtain the current depth h of the device, determine the cascaded nested cylinder as the adjustment object based on the current depth h, and control the motor to drive the piston to move in combination with the adjustment mode, adjust the drainage volume of the cascaded nested cylinder as the adjustment object, and realize the buoyancy adjustment of the device. The adjustment modes include a diving adjustment mode, an adaptive suspension adjustment mode, and a multi-level nested cylinder gradient buoyancy adjustment mode. The lower end of the third cascaded nested cylinder extends into the second cascaded nested cylinder and can move axially relative to the second cascaded nested cylinder. The first cascaded nested cylinder is located below the second cascaded nested cylinder. When the motor pushes the piston outward through the motor rod, the piston moves towards the bottom of the third cascaded nested cylinder in the third cascaded nested cylinder. After abutting the bottom of the third cascaded nested cylinder, it can drive the third cascaded nested cylinder to move downward relative to the second cascaded nested cylinder until the lower end of the third cascaded nested cylinder passes through the lower end of the second cascaded nested cylinder and extends into the first cascaded nested cylinder, moving axially relative to the first cascaded nested cylinder. When the third cascaded nested cylinder is used as the adjustment object, the drainage volume of the third cascaded nested cylinder is adjusted by adjusting the position of the piston in the third cascaded nested cylinder; when the second cascaded nested cylinder is used as the adjustment object, the drainage volume of the second cascaded nested cylinder is adjusted by adjusting the position of the lower end of the third cascaded nested cylinder in the second cascaded nested cylinder; when the first cascaded nested cylinder is used as the adjustment object, the drainage volume of the first cascaded nested cylinder is adjusted by adjusting the position of the lower end of the third cascaded nested cylinder extending into the first cascaded nested cylinder.

2. The buoyancy adjustment method according to claim 1, characterized in that, When the adjustment mode is the diving adjustment mode, the control method includes: (211) Obtain the set submersion and suspension depth H, and query the lookup table to determine the adjustment object that is compatible with the submersion and suspension depth; (212) Control the motor to drive the piston to move, so that the piston or the third-stage nested cylinder moves to the position corresponding to the adjustment object; (213) The current depth h of the device is acquired in real time and compared with the suspension depth H. When h is consistent with H, the motor is turned off and the current state is maintained.

3. The buoyancy adjustment method according to claim 2, characterized in that, In the diving adjustment mode, when the diving speed of the device exceeds the preset safety threshold, the control motor pushes the piston outward, with an adjustment range of Δd1, to increase the buoyancy of the device.

4. The buoyancy adjustment method according to claim 3, characterized in that, In the diving adjustment mode, when the diving speed of the device decreases within a safe threshold, it also includes controlling the internal piston of the motor, with an adjustment range of Δd2, where Δd2 < Δd1.

5. The buoyancy adjustment method according to any one of claims 2-4, characterized in that, When the adjustment mode is an adaptive floating adjustment mode, the control method includes: Calculate the current depth offset Δh, Δh = |hH|; If Δh≤0.1H, maintain the current regulating object and pressure, and do not take any action; If Δh > 0.1H and h > H, control the motor to push the piston outward, increasing the preset first drainage volume V1, continue to detect Δh, and repeat this adjustment step until Δh ≤ 0.1H; If Δh > 0.1H and h < H, control the motor to pull back the piston, reduce the preset second drainage volume V2, continue to detect Δh, and repeat this adjustment step to fine-tune until Δh ≤ 0.1H.

6. The buoyancy adjustment method according to claim 5, characterized in that, It also includes the step of calculating the motor's outward stroke based on V1 and V2: Obtain the cross-sectional area S of the inner cavity of the object being adjusted, control the stroke of the outward piston of the motor to D1=V1 / S, and control the stroke of the retracting piston of the motor to D2=V2 / S.

7. The buoyancy adjustment method according to claim 6, characterized in that, Obtain the current ambient water pressure P, and control the motor output thrust to be greater than P*S.

8. The buoyancy adjustment method according to claim 5, characterized in that, The values ​​of V1 and V2 range from 0.01 to 0.5L.

9. The buoyancy adjustment method according to any one of claims 2-4, characterized in that, When the adjustment mode is a multi-stage nested cylinder gradient upward adjustment mode, the control method includes: (221) Receive the upward command, identify the cascaded nested cylinder that is currently being adjusted, and if it is the third cascaded nested cylinder, control the motor to push the piston outward; (222) The depth of the device is acquired in real time. When the adjustment object matched by the depth is the second-level nested cylinder, the motor is controlled to push the piston outward, which drives the lower end of the third-level nested cylinder to move axially in the second-level nested cylinder. (223) When the depth of the device matches the first cascade nested cylinder, the control motor continues to push the piston outward, so that the lower end of the third cascade nested cylinder is inserted into the first cascade nested cylinder until the maximum stroke is reached.

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