Underwater glider capable of realizing spot hover and spot hover method

Abstract

The invention relates to the field of underwater gliders, in particular to an underwater glider capable of achieving spot hovering and a spot hovering method. The underwater glider comprises a streamline cabin, a pump arranged in the cabin from front to back in the longitudinal axis direction, a balance weight adjusting assembly and a vector propeller assembly arranged on the outer side of the cabin and located behind the balance weight adjusting assembly, and the balance weight adjusting assembly comprises a lead screw and a battery cabin also serving as a balance weight. The screw rod comprises a front threaded section and a rear threaded section which are opposite in rotation direction, the battery cabin is connected to the rear threaded section through a rear nut seat, the battery cabin is located at the neutral position of the glider in the initial state, the pump is provided with a communicating water opening extending out of the cabin, and a piston rod of the pump is connected to the front threaded section through a front nut seat; the piston rod moves backwards to enable the pump to suck water, the battery cabin moves forwards to enable the gravity center of the glider to move forwards, on the contrary, the gravity center of the glider moves backwards, and the underwater glider has the advantage of being capable of achieving dual-mode operation of long-distance gliding and spot hovering.

Description

Technical Field

[0001] This invention relates to the field of underwater glider technology, and more particularly to an underwater glider capable of hovering at a fixed point and a method for hovering at a fixed point. Background Technology

[0002] Current underwater vehicle technology can be divided into three categories: traditional underwater gliders, which rely solely on buoyancy and fixed wings, move passively, and have no hovering capability; hybrid-drive gliders, which are equipped with 1-2 horizontal thrusters, used only to assist in speed increase or turning, with a single thrust direction that cannot generate a vertical component to offset buoyancy imbalance, and lack hovering function; and all-drive AUVs / ROVs, which use multiple thrusters to achieve hovering, but have low energy efficiency, only a few hours of endurance, and high cost.

[0003] In the prior art, Chinese Patent No. CN108216532A, published on June 29, 2018, discloses a fixed-wing amphibious sea-air vehicle. This amphibious vehicle can function as an underwater glider or an aerial vehicle. Specifically, it includes an outer shell assembly, a flight assembly, and an aerodynamic buoyancy assembly. The flight assembly includes a fixed wing and a rotor assembly. The fixed wing provides lift when the vehicle is flying horizontally or provides gliding power underwater. The rotor assembly uses four foldable propellers to tilt the bow of the fuselage through speed differences and to generate thrust to propel the vehicle in the air. The aerodynamic buoyancy assembly includes an annular airbag, a pressure sensor, and inflation / deflation valves. By inflating and deflation of gas into the annular airbag, the net buoyancy in the water is adjusted, driving the glider to rise to the water surface, thus preparing for vertical takeoff and landing or water-air mode switching.

[0004] In this scheme, although the aerodynamic buoyancy components can adjust the aircraft's center of gravity, enabling zigzag gliding with the help of fixed wings and hovering underwater with the help of rotor components, the aerodynamic buoyancy components rely on pressure-resistant components and devices such as high-pressure air sources, inflation and deflation valves, and air pressure sensors. On the one hand, this results in a large overall weight and high power consumption during hovering operations. On the other hand, the limited capacity of the high-pressure air source leads to significant limitations in the glider's endurance and power consumption limits for a single operation. In addition, during the vertical attitude conversion process using the quadcopter thrusters to provide thrust, the combined thrust generated by the quadcopters may cause the aircraft to spin. In some cases, servos are also required to de-spin, further increasing the structural complexity. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an underwater glider capable of hovering at a fixed point and a method for hovering at a fixed point. The underwater glider and the method for hovering at a fixed point have the advantages of being able to achieve hovering at a fixed point, long-endurance operation, simple structure, and low algorithm cost.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This application first provides an underwater glider capable of hovering in a fixed position, including a streamlined cabin, a pump arranged from front to back along the longitudinal axis within the cabin, a counterweight adjustment assembly, and a vector thruster assembly located outside the cabin and behind the counterweight adjustment assembly, wherein... The counterweight adjustment assembly includes a lead screw and a battery compartment that also serves as a counterweight. The lead screw includes a front threaded section and a rear threaded section with opposite rotation directions. The battery compartment is connected to the rear threaded section via a rear nut seat. In its initial state, the battery compartment is located at the center of gravity of the glider in a horizontal balanced posture. The pump has a water inlet extending out of the hull and its piston rod is connected to the front threaded section via a front nut seat. When the lead screw rotates clockwise, the piston rod moves backward, causing the pump to draw in water and the battery compartment to move forward, thus shifting the glider's center of gravity forward. Conversely, rotating counterclockwise causes the glider's center of gravity to move backward. The vector thruster assembly includes an X-shaped wing that extends outward from the outer side of the cabin and is symmetrically arranged along the width of the glider, and a propeller thruster located at the outer end of each wing. The X-shaped wing provides thrust at a set angle of attack to drive the glider to glide forward. The thrust direction of the thruster is parallel to the longitudinal axis and is used to provide the glider with yaw moment, vertical attitude conversion moment, or hovering buoyancy.

[0007] To optimize the above plan, the following measures were also taken: Preferably, the pump is fixed to the front end of the lead screw and is adjacent to the lead screw, the front threaded section is adjacent to the rear threaded section, and the lead of the front threaded section is [missing information]. The lead of the rear thread segment is The piston rod has a mass of m1, and the battery compartment has a mass of m2. < ; With the lead screw tip as the origin O, the initial coordinate position of the piston rod on the lead screw is: The initial coordinate position of the battery compartment on the lead screw is: If the length of the piston rod is L, then ,in = .

[0008] As a preferred option ≤ .

[0009] Preferably, the cabin is also equipped with a depth gauge for measuring the current depth of the glider. When the underwater glider is in a vertical hovering state, its gravity G and the thrust of the propeller are measured. The buoyancy experienced by the glider itself =ρg (t) and environmental disturbances The following force equilibrium equations must be satisfied: +ρg (t)- + =0 in, (t) represents the volume of water displaced by the glider at time t when the piston rod of the pump moves. The resultant force of the thrust from the four propellers, Calculate using the following formula: =K·Δz Where Δz is the depth deviation from the target hovering point, which is measured and fed back by the depth gauge, and K is the proportional coefficient, which is determined by the target buoyancy compensation method.

[0010] Preferably, the magnitude of the gravity G is ,in The min represents the total mass of the glider when the pump is dry. < <max min ,max These represent the minimum and maximum values ​​of the buoyancy force acting on the glider, respectively.

[0011] Preferably, the system also includes a drive control assembly located in the cabin. The drive control assembly includes a servo motor, a distributor, a lead screw motor driver, and a navigation controller. The servo motor provides power to the lead screw drive. The lead screw motor driver drives the servo motor to rotate. The lead screw motor driver is connected to a power source through the distributor. The navigation controller is electrically connected to the lead screw motor driver to control the forward and reverse rotation of the servo motor. The navigation controller is electrically connected to the propeller thruster through an electronic speed controller to control the thrust magnitude and direction of the propeller.

[0012] Preferably, the cabin includes a main cabin tube and a front cover and a rear cover respectively sealed and connected to the main cabin tube, the pump is disposed between the main cabin tube and the front cover, and the drive control assembly is disposed between the main cabin tube and the rear cover. The main compartment is provided with multiple radial fixing frames spaced apart along the longitudinal axis. Multiple parallel optical axes are provided on the multiple radial fixing frames along the circumferential direction surrounding the lead screw. The extension direction of the optical axes is parallel to the longitudinal axis. The battery compartment is provided with linear bearings that slide with the optical axes. The battery compartment is provided with multiple battery limiting holes. The multiple battery limiting holes are staggered from the linear bearings and are equally spaced along the circumferential direction surrounding the rear nut seat.

[0013] Preferably, the propulsion unit includes a front fairing, a motor mount, a thrust motor, a duct housing, a propeller, and a tail fairing. The propeller is coaxially mounted inside the duct housing, the motor mount is located at the front end of the duct housing, the thrust motor is located inside the motor mount, the propeller extends forward out of the duct housing and is connected to the motor shaft of the thrust motor, the front fairing is fixed to the front end of the motor mount, and the front fairing has a streamlined conical structure for rectifying and guiding water flow into the duct, and the tail fairing is fixed to the rear end of the duct housing for wake rectification and protection.

[0014] Preferably, the outer wall of the battery compartment slides in contact with the inner wall of the cabin, and the cabin is made of a thermally conductive material to conduct heat from the battery compartment to the outside.

[0015] Furthermore, a hovering method based on the aforementioned underwater glider capable of hovering at a fixed point is proposed, comprising the following steps: S1. Hovering posture transition, specifically including: S1-1. Control the lead screw to rotate in the forward direction, so that the piston rod moves backward in the pump to make the pump suck water and the battery compartment moves forward in the cabin, so that the center of gravity of the underwater glider moves to the front of the cabin and the bow of the glider tilts downward. S1-2. Drive each propeller to rotate in the same direction and opposite directions on the X-shaped wing to generate thrust, so that the four propellers generate pitching torque, drive the stern of the glider to tilt upward and change the cabin to a vertical attitude. S2. Adjust the center of gravity position and achieve fixed-point hovering, specifically: S2-1. After the glider completes the vertical attitude conversion, the battery compartment moves to the predetermined center of gravity position, and the net buoyancy is adjusted by pumping water in and out or controlling the thrusters to rotate synchronously to drive the glider to the target depth position. S2-2. After the glider reaches the target depth, it first adjusts the net buoyancy by controlling the pump to suck in and drain water, correcting the glider's depth position deviation caused by external disturbance forces, thereby achieving fixed-point hovering. When the deviation cannot be completely corrected by pumping water, the thruster is controlled to rotate synchronously to compensate for the net buoyancy deviation until the fixed-point hovering is maintained.

[0016] Because of the above-described solutions, one or more technical solutions provided in this application embodiment have at least the following technical effects or advantages: This design relies solely on a coupled architecture consisting of a pump and a battery compartment controlled by a single lead screw for center of gravity adjustment. This significantly simplifies the internal structural layout of the cabin. The battery compartment also serves as a counterweight, achieving dual functionality and reducing the weight of the aircraft. The pump, through its own suction and discharge control, adjusts the aircraft's center of gravity on one hand, enabling sawtooth gliding in conjunction with the X-shaped wing. On the other hand, as a core mechanism, it adjusts net buoyancy, propelling the vertically oriented glider to the target depth and compensating for positional deviations caused by external disturbances during hovering. The vector thruster assembly serves only as an auxiliary mechanism, compensating for net buoyancy deviations to maintain a fixed hovering state. Compared to a net buoyancy adjustment device composed of an aerodynamic buoyancy assembly and a thruster, this pump-thruster combined net buoyancy adjustment device not only helps reduce hovering power consumption but also eliminates reliance on an external air source, enabling long-duration operation.

[0017] On the other hand, the adjustment of the glider's center of gravity position and net buoyancy in vertical attitude is achieved by controlling the rotation of the lead screw, and the thruster only needs to operate intermittently. This simplifies the control process, makes the adjustment operation fast, and makes the glider highly adaptable to ocean current disturbances, reliably maintain its underwater hovering position, and has good system robustness and reliable stability.

[0018] On the other hand, during the vertical attitude transition of the glider, the vector thruster assembly adopts a diagonal same-direction and adjacent opposite-direction rotation strategy. While providing pitch torque to drive the cabin from horizontal to vertical attitude, it also provides self-balancing anti-torque, that is, left-hand rotation torque equals right-hand rotation torque. No additional servo motor is needed to de-rotate, and the structure is simple and reliable. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only involve some embodiments of this application and should not be construed as limiting this application.

[0020] Figure 1 This is a schematic diagram of the overall structure of the underwater glider in this embodiment.

[0021] Figure 2 This is a partial structural diagram of the underwater glider in this embodiment.

[0022] Figure 3 This is a schematic diagram of the underwater glider cabin in this embodiment.

[0023] Figure 4 This is an exploded view of the underwater glider vector thruster assembly in this embodiment.

[0024] Figure 5 This is a schematic diagram of the front structure of the underwater glider in this embodiment.

[0025] Figure 6 This is a schematic diagram of the underwater glider battery compartment in this embodiment.

[0026] Figure 7 yes Figure 4 A schematic diagram of the thruster.

[0027] Figure 8 This is a schematic diagram of the underwater glider transitioning from a gliding attitude to a hovering attitude in this embodiment.

[0028] Figure 9 This is a schematic diagram of the dimensions of the underwater glider in this embodiment.

[0029] Figure label: 1. Engine compartment; 11. Main compartment tube; 111. Radial mounting bracket; 112. Optical axis; 113. Axial mounting bracket; 12. Front end cover; 121. Front axial sealing flange; 122. Sealing ring; 123. First connecting bolt; 13. Rear end cover; 131. Rear axial sealing flange; 133. Second connecting bolt; 14. Pump; 141. Piston rod; 142. Front nut seat; 15. Lead screw; 15a. Front threaded section; 15b. Rear threaded section; 16. Battery compartment; 161. Rear nut seat; 162. Linear bearing; 163. Battery limiting hole; 164. 17. Battery; 170. Vector thruster assembly; 171. Sleeve; 172. X-wing; 173. Cage; 174. Axial connection frame; 175. Cable routing channel; 176. Electronic speed controller; 177. Thruster; 176a. Thruster I; 176b. Thruster II; 176c. Thruster III; 176d. Thruster IV; 181. Front fairing; 182. Motor mount; 184. Duct housing; 185. Propeller; 186. Tail fairing; 191. Servo motor; 193. Screw motor driver; 194. Flight controller. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings, so as to more clearly understand the purpose, features and advantages of this invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of this invention, but are only for illustrating the essential spirit of the technical solutions of this invention. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0031] Unless the context requires otherwise, throughout the specification and claims, the word “comprising” and its variations, such as “including” and “having”, shall be understood to have an open, inclusive meaning, that is, to be interpreted as “including, but not limited to”.

[0032] Throughout this specification, references to "an embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the appearance of "in an embodiment" or "an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0033] The singular forms “a” and “the” used in this specification and the appended claims include plural references unless otherwise expressly stated herein. It should be noted that the term “or” is generally used to mean “and / or” unless otherwise expressly stated herein.

[0034] In the following description, in order to clearly demonstrate the structure and working method of the present invention, a number of directional terms will be used. However, terms such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", and "down" should be understood as convenient terms and not as limiting terms.

[0035] The implementation details of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following content is only for the convenience of understanding the implementation details and is not necessary for implementing this solution.

[0036] refer to Figures 1 to 9 As shown, this embodiment proposes an underwater glider capable of hovering at a fixed point and a method for doing so. The aim is to solve problems in existing underwater gliders such as complex center of gravity adjustment devices, large overall weight, limited endurance, delayed adjustment response, and body spin. This method not only greatly simplifies the internal structural layout of the cabin, reduces the overall weight, and extends endurance, but also features a simple and reliable control process, significantly improving energy efficiency. Furthermore, the hovering method based on this underwater glider enables the glider to eliminate spin during vertical attitude transitions, eliminating the need for additional despin servos or other structures or devices, thereby further reducing equipment costs.

[0037] Specifically, the underwater glider capable of hovering in a fixed position can be used for applications such as ocean observation, underwater facility inspection, or environmental monitoring. It includes a streamlined cabin 1, a pump 14 arranged along the longitudinal axis from front to back within the cabin 1, a counterweight adjustment assembly, and a vector thruster assembly 17 located outside the cabin 1 and behind the counterweight adjustment assembly. The cabin 1 is long and cylindrical with streamlined conical ends. The counterweight adjustment assembly includes a lead screw 15 and a battery compartment 16 that also serves as a counterweight. The lead screw 15 includes a front threaded section 15a and a rear threaded section 15b with opposite rotation directions. The battery compartment 16 is connected via a rear nut seat 16. 1. Connected to the rear threaded section 15b, the battery compartment 16 is initially positioned in the neutral position of the glider. The pump 14 has a water inlet extending out of the cabin 1, and its piston rod 141 is connected to the front threaded section 15a via the front nut seat 142. When the screw 15 rotates forward, the piston rod 141 moves backward, causing the pump 14 to draw in water and the battery compartment 16 to move forward, thus shifting the glider's center of gravity forward. Conversely, it shifts backward, causing the glider's center of gravity to move backward. The vector thruster assembly 17 includes X-shaped wings 171 extending outward from the outside of the cabin 1 and arranged in a mirror-symmetrical manner along the width of the glider, and propeller thrusters 176 located at the outer ends of each wing. Figure 5 As shown, the x-arrow indicates one orientation in the width direction, and the y-arrow indicates the vertically upward orientation in the height direction of the underwater glider. The X-shaped wing 171 provides thrust at a set angle of attack to drive the glider to glide forward in a sawtooth pattern. The thrust direction of the thruster 176 is parallel to the longitudinal axis and is used to provide the glider with yaw torque, vertical attitude conversion torque, or hovering buoyancy.

[0038] In this embodiment, the underwater glider drives the center of gravity of the glider to move back and forth by controlling the forward and reverse rotation of the control screw 15. With the thrust provided by the X-shaped wing 171, it can achieve zigzag gliding. With the pitch torque provided by the four thrusters 176, it can drive the cabin 1 to complete the vertical attitude conversion. In the vertical attitude, by controlling the pump 14 to suck water and / or controlling the synchronous rotation of the thrusters 176, the net buoyancy is adjusted to drive the glider to the target depth position. After reaching the target depth position, by controlling the pump 14 to suck water and / or controlling the synchronous rotation of the thrusters 176, the net buoyancy is adjusted to correct the glider's depth position deviation caused by external disturbance. When the deviation exceeds the limit, the synchronous rotation of the thrusters 176 compensates for the net buoyancy deviation, thereby ensuring stationary hovering.

[0039] Specifically, in its initial state, the battery compartment 16 is located at the center of gravity when the glider is in torque balance, i.e., the neutral position. In underwater gliding mode, the navigation controller controls the lead screw 15 to rotate forward, and the piston rod 141 inside the pump 14 moves backward under the drive of the front nut seat 142, causing the pump 14 to draw in water. At the same time, the battery compartment 16 moves forward under the drive of the rear nut seat 161. The combined effect of the two increases the weight of the front half of the cabin, shifts the center of gravity of the glider forward, and tilts the bow downward. At the set angle of attack, the X-shaped wing 171 is provided with thrust for the glider to glide forward under the action of water flow pressure, propelling the glider to dive and move forward. When the glider reaches a certain depth, the navigation controller reverses the control screw 15, and the piston rod 141 inside the pump 14 moves forward under the action of the front nut seat 142, causing the pump 14 to drain water. At the same time, the battery compartment 16 moves backward under the action of the rear nut seat 161, causing the glider's center of gravity to shift backward and the bow to tilt upward. At the set angle of attack, the X-shaped wing 171 is provided with thrust for the glider to glide forward by the water flow pressure, propelling the glider to rise and move forward, forming a sawtooth glide.

[0040] When switching to hovering mode is required, upon receiving a hovering command, the navigation controller 194 controls the lead screw 15 to rotate clockwise, shifting the glider's center of gravity forward and tilting the bow downward. Then, the four propeller thrusters 176 are activated, generating a combined upward vertical thrust or pitching moment through differential control, propelling the glider to complete the vertical attitude transition or hovering attitude transition. In this embodiment, the thrusters 176 are driven to rotate and generate thrust according to a rotation strategy where the thrust directions on the X-shaped wing 171 are diagonally opposite and adjacently opposite. Figure 5 As shown, thrusters 176b and 176d rotate clockwise, while thrusters 176a and 176c rotate counterclockwise. This configuration ensures that the counter-torques generated by the four thrusters 176 cancel each other out, resulting in a total left-handed torque equal to a total right-handed torque, thus preventing fuselage spin. Simultaneously, the counter-rotation of adjacent thrusters 176 reduces tip vortex interference, improving thrust efficiency and attitude stability during hovering.

[0041] After the glider completes the vertical attitude transition, the battery compartment 16 moves to the predetermined center of gravity position. A detailed example of the center of gravity position is given below, and will not be repeated here. At this time, water can be pumped in and out by the pump 14, or the thruster 176 can be controlled to rotate synchronously to adjust the net buoyancy and drive the glider to the target depth position, thereby achieving stationary hovering.

[0042] In this embodiment, the center of gravity adjustment relies solely on the coupled architecture of the pump 14 and battery compartment 16, controlled by a single lead screw 15. This greatly simplifies the structural layout within the cabin 1. The battery compartment 16 also serves as a counterweight, achieving dual functionality and reducing the weight of the aircraft. The pump 14, through its own suction and discharge control, is used to adjust the center of gravity of the aircraft, enabling zigzag gliding in conjunction with the X-shaped wing 171. Furthermore, as a core mechanism, it adjusts net buoyancy, driving the vertically oriented glider to the target depth point and compensating for positional deviations caused by external disturbances during hovering. The thruster 176 serves only as an auxiliary mechanism, compensating for net buoyancy deviations to maintain a fixed hovering state. Compared to a net buoyancy adjustment device composed of an aerodynamic buoyancy component and a thruster, this pump-thruster combined net buoyancy adjustment device not only helps reduce hovering power consumption but also does not rely on an external air source, enabling long-duration operation.

[0043] In this embodiment, regarding energy management, in underwater gliding mode, the thruster 176 is turned off, and only the navigation controller 194 and sensors consume power, approximately 2W, with a flight time of up to 30 days. In hovering mode, the thruster 176 operates intermittently with a duty cycle of approximately 20%, an average power consumption of 15W, and a flight time of 72 hours. When the battery level drops below 20%, the glider is forced to switch back to gliding mode for return.

[0044] On the other hand, the adjustment of the glider's center of gravity position and net buoyancy in vertical attitude is achieved by controlling the rotation of the lead screw 15. The thruster 176 only needs to compensate for the small residual buoyancy, so it only needs to operate intermittently. This simplifies the control process, makes the adjustment operation fast, makes the glider highly adaptable to ocean current disturbances, maintains a reliable underwater hovering position, and has good system robustness and reliable stability.

[0045] In this embodiment, to demonstrate the above-mentioned technical solution for glider hovering in a fixed position more in detail, a method for hovering in a fixed position based on the aforementioned underwater glider capable of hovering in a fixed position is also proposed, including the following steps: S1. Hovering posture transition, specifically including: S1-1. Control the lead screw 15 to rotate in the forward direction, so that the piston rod 141 moves backward in the pump 14 to make the pump 14 suck water and the battery compartment 16 moves forward in the cabin 1, so that the center of gravity of the underwater glider moves to the front of the cabin and the bow of the glider tilts downward. S1-2. Drive each propeller 176 to rotate in the same direction and opposite directions on the X-shaped wing 171 to generate thrust, so that the four propellers 176 generate pitching moment, drive the stern of the glider to tilt upward and change the cabin 1 to a vertical attitude. S2. Adjust the center of gravity position and achieve fixed-point hovering, specifically: S2-1. After the glider completes the vertical attitude conversion, the battery compartment 16 moves to the predetermined center of gravity position, and the pump 14 sucks in water or controls the thruster to rotate synchronously, adjusting the net buoyancy to drive the glider to the target depth position. S2-2. After the glider reaches the target depth, it first adjusts the net buoyancy by controlling the pump 14 to suck in and drain water, correcting the glider's depth position deviation caused by external disturbance forces, thereby achieving fixed-point hovering. When the deviation cannot be completely corrected by pumping water through the pump 14, the thruster 176 is controlled to rotate synchronously to compensate for the net buoyancy deviation until the fixed-point hovering is maintained.

[0046] By employing the above method, during the glider's vertical attitude transition, the vector thruster assembly 17 adopts a diagonal, same-direction, adjacent, opposite-direction rotation strategy. While providing pitch torque to drive the cabin 1 from a horizontal to a vertical attitude, it also provides self-balancing anti-torque, meaning the left-hand rotation torque equals the right-hand rotation torque, eliminating the need for additional servo motors for de-rotation, resulting in a simple and reliable structure. Simultaneously, the counterweight adjustment assembly drives the battery compartment 16 to move along the longitudinal axis of the cabin 1, adjusting the overall center of gravity to be vertically aligned with the center of buoyancy. This, combined with the thrust distribution of the thrusters 176, optimizes pitch and roll attitude. A nine-axis IMU and depth gauge are installed within the cabin 1 to monitor attitude deviations and depth changes in real time. In some situations, the navigation controller 194 can incorporate a nonlinear model predictive control algorithm to dynamically calculate thrust distribution and center of gravity fine-tuning, forming a closed-loop feedback loop. This ensures stable vertical attitude even under complex ocean current disturbances, enabling high-precision fixed-point hovering and observation.

[0047] like Figure 8 The diagram illustrates the process by which an underwater glider transitions from a gliding attitude to a hovering attitude (vertical attitude). From a gliding state with deployed wings, the glider gradually switches to a hovering state that provides lift in the water, controlled by four thrusters 176, achieving flexible switching between different modes.

[0048] In some methods, yaw in a predetermined direction can also be achieved by controlling the vector thruster assembly 17, specifically, such as Figure 5 As shown, when the nose needs to yaw to the right, thrusters 176b and 176c are rotated clockwise, while thrusters 176a and 176d are rotated counterclockwise. Thrusters 176b and 176c generate a rightward water flow reaction force, while thrusters 176a and 176d generate a leftward water flow reaction force. The sum of the thrust vectors of these four thrusters is zero, and the torques around the vertical axis of the fuselage are superimposed in a clockwise direction, driving the nose to yaw to the right. When the nose needs to yaw to the left, thrusters 176a and 176d are rotated counterclockwise, generating a counterclockwise yaw torque.

[0049] In this embodiment, as Figure 9As shown, the pump 14 is fixed to the front end of the lead screw 15 and is adjacent to the lead screw 15. The front threaded section 15a and the rear threaded section 15b are adjacent to each other. The lead of the front threaded section 15a is... The lead of the rear threaded section 15b is The piston rod 141 has a mass of m1, and the battery compartment 16 has a mass of m2. < With the front end of the lead screw 15 as the origin O, the initial coordinate position of the piston rod 141 (including the front nut seat 142) on the lead screw 15 is: The initial coordinate position of the battery compartment 16 (including the rear nut seat) on the lead screw 15 is: If the length of the piston rod 141 is L, then ,in = .

[0050] In this embodiment, to reduce the longitudinal length of the cabin 1, the pump 14 and the lead screw 15 are arranged adjacent to each other along the longitudinal axis. Taking the front end of the lead screw 15 (where it connects to the pump 14) as the origin O, and the horizontal direction to the right (pointing towards the rear end of the lead screw 15) as the positive X-axis, the length of the lead screw 15 is H, and its rear end is located at X=H. The pump 14 is fixed to the front end of the lead screw, with a length of... Its shell mass is The center of mass is located at X= / 2, the mass of piston rod 141 (including front nut seat 142) is The position on lead screw 15 is Movement range ∈[L [L], where L is the length of piston rod 141 (when When =L, the piston is located at the rear end of the pump 14, X=0. =L When the piston is located at the front end of the pump, X= The battery compartment 16 (including the rear nut seat 161 and the fully loaded battery 164) has a mass of Position on lead screw 15 Movement range ∈[L, H], the mass of screw 15 is M, uniformly distributed, and the center of mass is located at X=H / 2.

[0051] In one scenario, the battery compartment 16 can be allocated as much capacity as possible to increase underwater endurance, while also considering water quality. In one scenario, the battery compartment mass m1 ranges from 50 to 200 kg. The range is 0.5–2 kg, therefore the change in center of gravity during adjustment is negligible. The change in the center of gravity position of the pump 14 and the counterweight adjustment assembly is calculated according to the following center of gravity coordinate formula: in, = , The following motion constraints must be satisfied: in, The angle of rotation of the lead screw; Here let the constant D = = ,but: Where A = B= , = ; When B > 0, that is hour, Follow It increases with the increase of, and with The decrease is due to the decrease. exist Take the minimum value, that is = When the minimum value is obtained. ,in Determined by D and lead, the initial position D can be adjusted to achieve... As small as possible By minimizing the size of the pump 14 and the counterweight adjustment assembly, the center of gravity of the glider can be lowered. Given a fixed center of buoyancy in a hovering state, a lower center of gravity results in a greater restoring torque against the tilt of the cabin 1, thus improving the glider's stability. Specifically... Limited by According to the itinerary The range of values ​​for D and D= = Get, when hour, =L, that is, the rear nut seat 161 takes the minimum endpoint value, at this time = When the front nut seat 142 reaches its maximum value, the piston rod 141 of the pump 14 moves to its rear end within the range, and the pump 14 is full of water. Correspondingly, when the water is emptied from the pump 14, =L At that time, the center of gravity reaches its maximum value.

[0052] In other words, when < and Where, D= = , , Considering the initial positions of the front nut seat 142 and the rear nut seat 161 respectively, the glider's center of gravity changes linearly with the movement of the nut seat 161. The glider can adjust its center of gravity to be closest to its front end, thus: 1. Applying a sufficiently large bow pitch moment to the glider, causing the nose to drop rapidly. Combined with the vector thruster assembly 17, the glider can quickly switch from gliding to vertical hovering; 2. In vertical hovering, the center of gravity is at its lowest point, maximizing the anti-overturning moment of the cabin 1 and greatly improving its resistance to wind, waves, and currents, allowing it to maintain hovering posture to the maximum extent; 3. The center of gravity changes linearly in the same direction with the movement of the nut seat, making it easy to control and reducing algorithm costs.

[0053] In this embodiment, the process of center of gravity adjustment and the process of net buoyancy adjustment in hovering posture are coupled together by a lead screw. That is, controlling the rotation of the lead screw 15 causes the piston rod 141 inside the pump 14 to move, thereby controlling the pump 14 to draw in or drain water. During this process, the battery compartment 16 also moves accordingly, meaning that the center of gravity of the aircraft will also change to some extent. However, the amount of water adjusted in the pump 14 is small, usually <1ml, so the rotation of the lead screw 15 is small, the range of movement of the battery compartment 16 is small, and the change in the center of gravity is small. The impact on the stability of the hovering posture can be ignored. In one scenario... ≤ This results in a smaller movement distance of the battery compartment 16 on the lead screw 15, given that the piston rod 141 inside the pump 14 moves a fixed distance as the lead screw 15 rotates. In other words, the process of adjusting net buoyancy by changing the amount of water inside the pump 14 during hovering further reduces the impact on the change in the glider's center of gravity.

[0054] In this embodiment, the cabin 1 is also equipped with a depth gauge for measuring the current depth of the glider. When the underwater glider is in a vertical hovering state, its gravity G and the thrust of the thruster 176 are measured. The buoyancy force on the glider itself is Fi = ρg (t) and environmental disturbance forces The following force equilibrium equations must be satisfied: +ρg (t)- + =0 in, (t) represents the volume of water displaced by the glider at time t when the piston rod 141 of the pump 14 moves. The resultant force of 176 thrust from the four thrusters, Calculate using the following formula: =K·Δz Where Δz is the depth deviation from the target hovering point, which is measured and fed back by the depth gauge, and K is the proportional coefficient, which is determined by the target buoyancy compensation method.

[0055] Specifically, the magnitude of the gravity G is ,in Let Fi represent the total mass of the glider in the absence of water in pump 14, minFi < <maxFi, minFi, and maxFi represent the minimum and maximum buoyancy forces acting on the glider itself, respectively, which can be adjusted by the pump 14 to draw water. Specifically, in one case, when the pump 14 is full of water, Fi = minFi, and when the pump 14 is empty of water, Fi = maxFi.

[0056] In this embodiment, minFi < <maxFi indicates that the buoyancy and gravity acting on the glider as a whole are not significantly different. Ideally, when hovering in a fixed position, Fi=G, and the glider is in equilibrium in the vertical direction. When subjected to external disturbances... At certain times, within a certain range, the buoyancy Fi experienced by the glider can be increased or decreased by pumping water in or out through pump 14 to achieve balance. Obviously, its adjustable range is limited. When it exceeds the range, the thrust provided by the thruster 176 is used to further adjust it. To balance the net buoyancy deviation, the operating frequency and power of the thruster 176 can be reduced, which helps to significantly reduce hovering power consumption.

[0057] Specifically, refer to Figure 3 As shown, it also includes a drive control assembly located in the cabin 1. The drive control assembly includes a servo motor 191, a power distribution board, a lead screw motor driver 193, and a navigation controller 194. The servo motor 191 provides power to the lead screw 15. The lead screw motor driver 193 drives the servo motor 191 to rotate. The lead screw motor driver 193 is connected to the power supply through the power distribution board. The navigation controller 194 is electrically connected to the lead screw motor driver 193 to control the forward and reverse rotation of the servo motor 191. The navigation controller is electrically connected to the propeller thruster 176 through an electronic speed controller 175 to control the thrust magnitude and direction of the thruster 176.

[0058] Specifically, refer to Figures 1 to 3The engine compartment 1 includes a main cylinder 11 and a front cover 12 and a rear cover 13 respectively sealed and connected to the main cylinder 11. The pump 14 is located between the main cylinder 11 and the front cover 12. The drive control assembly is located between the main cylinder 11 and the rear cover 13. Multiple radial fixing brackets 111 are spaced apart along the longitudinal axis inside the main cylinder 11. Multiple parallel optical axes 112 are provided on the multiple radial fixing brackets 111 along the circumferential direction surrounding the lead screw 15. The extension direction of the optical axes 112 is parallel to the longitudinal axis. The battery compartment 16 is provided with a linear bearing 162 that slides with the optical axis 112. The battery compartment 16 is provided with multiple battery limiting holes 163. Here, 6 battery limiting holes 163 are provided. The multiple battery limiting holes 163 are staggered from the linear bearings 162 and are equally spaced along the circumferential direction surrounding the rear nut seat. In the working state, a battery 164 is inserted into each battery limiting hole 163.

[0059] Here, a modular battery compartment design is adopted. Battery compartment 16 is an independent pressure-resistant and sealed compartment, which is connected to the navigation controller 194 through a watertight plug. In one configuration, battery 164 uses 11.1V 18650 lithium polymer batteries, a total of 6 cells, which is sufficient for long-term operation.

[0060] In terms of thermal management, the outer wall of the battery compartment 16 is in sliding contact with the inner wall of the cabin 1. The cabin 1 is made of thermally conductive material to conduct heat from the battery compartment 16 to the outside. The outer shell of the battery compartment 16 is in close contact with the cabin wall of the glider cabin 1. The cabin 1 has good thermal conductivity and can carry away heat from the battery 164 during gliding, preventing the battery from overheating.

[0061] In this embodiment, as Figure 2 and Figure 3 As shown, the main compartment 11 has a front axial sealing flange 121 at its front end, and a streamlined front cover 12 with an annular insertion part. The insertion part is inserted into the main compartment 11 by the inner ring of the front axial sealing flange 121. The insertion part and the front axial sealing flange 121 are waterproofed by one or more sealing rings 122, in this case, two. The front cover 12 and the front axial sealing flange 121 are fastened together by an axial first connecting bolt 123. The main compartment 11 has a rear axial sealing flange 131 at its rear end, and the rear cover 13 is fastened together with the rear axial sealing flange 131 by an axial connecting bolt.

[0062] In this embodiment, a horizontal axial fixing bracket 113 is fixed between a radial fixing bracket 111 near the rear axial sealing flange 131 along the longitudinal axis inside the cabin 1 and the rear axial sealing flange 131. The drive control assembly is fixed on the axial fixing bracket 113, wherein the servo motor 191 is located at the lower part of the axial fixing bracket 113, and the navigation controller 194 and the lead screw motor driver 193 are both located at the upper part of the axial fixing bracket 113. This separates the control components and the motor components, reducing electromagnetic interference. In one embodiment, a connecting ring is provided at the rear end of the axial fixing bracket 113, and the connecting ring is connected to the rear axial sealing flange 131 along the axial direction by a second connecting screw 133, making the overall structure more robust.

[0063] In this embodiment, the X-shaped wing 171 is detachably connected to the cabin 1 to improve the maintainability and ease of assembly of the glider. Specifically, the cabin 1 is fixedly provided with a sleeve 170 in the form of a hoop, and the X-shaped wing 171 is distributed along the circumferential direction of the sleeve 170. The cabin 1 is provided with a retainer 172 behind the sleeve 170. The electronic speed controller 175 is installed on the retainer 172. The rear end of the retainer 172 is fixedly connected to the rear axial sealing flange 131 through several axial connecting brackets 173. It also includes a wiring channel 174. The flight controller 194 is electrically connected to the thrusters 176 through the wiring channel 174 passing through the electronic speed controller 175. The main function of the electronic speed controller 175 is to adjust the speed of the four thrusters 176 to realize the transition from gliding to hovering.

[0064] In this embodiment, as Figure 4 and Figure 7 As shown, the thruster 176 includes a front fairing 181, a motor mount 182, a thrust motor (not shown), a duct housing 184, a propeller 185, and a tail fairing 186. The propeller 185 is coaxially mounted inside the duct housing 184. The motor mount 182 is located at the front end of the duct housing 184, and the thrust motor is located inside the motor mount 182. The propeller 185 extends forward out of the duct housing 184 and is connected to the motor shaft of the thrust motor. The front fairing 181 is fixed to the front end of the motor mount 182 and has a streamlined conical structure for rectifying and guiding water flow into the duct. The tail fairing 186 is fixed to the rear end of the duct housing 184 and serves to rectify and protect the wake.

[0065] In this embodiment, to facilitate understanding of the essence of the solution, a specific scenario is presented to illustrate the hovering operation process of an underwater glider, as follows: (1) When the mission is triggered, the sea-based control center or the preset program sends a hovering command to the glider navigation controller 194, specifying the target depth and hovering duration.

[0066] (2) Mode switching preparation: After receiving the instruction, the navigation controller 194 starts the attitude stabilization algorithm, and the four thrusters 176 enter the pre-start state.

[0067] (4) Center of gravity adjustment: The screw 15 drives the pump 14 and battery compartment 16 to adjust the center of gravity, causing the bow to tilt downward.

[0068] (3) Thrust start-up: The four thrusters 176 start up synchronously, generating vertical upward thrust based on the depth gauge feedback data to offset the current net buoyancy. At the same time, the center of gravity is adjusted so that the center of gravity of the whole machine is vertically aligned with the center of buoyancy, thus optimizing pitch stability.

[0069] (5) Depth positioning: When the glider approaches the target depth, the navigation controller 194 adjusts the speed of the thruster 176 in real time through the control algorithm to achieve accurate depth capture.

[0070] (6) Stable attitude: The nine-axis IMU continuously monitors the attitude deviation of the fuselage, and the flight controller 194 dynamically calculates the thrust distribution and center of gravity fine adjustment, driving the closed-loop correction of each component to maintain the vertical attitude.

[0071] (7) Hovering and maintaining stable hovering: After entering stable hovering, the navigation controller 194 operates in low power mode, maintains minimum thrust output and center of gravity compensation, and starts scientific payloads for fixed-point observation.

[0072] (8) Environmental monitoring: The navigation controller 194 monitors the status of the thruster 176, the battery 164 balance and changes in the external flow field in real time, and adaptively adjusts the control parameters to resist ocean current disturbances.

[0073] (9) After the mission is completed and hovering observation is completed, the navigation controller 194 receives the command to resume gliding and the four thrusters 176 gradually reduce the thrust output.

[0074] (10) Gliding recovery, battery compartment 16 (counterweight block) moves back to the neutral position, X-shaped wings unfold to 90°, glider resumes net buoyancy drive, turns into zigzag navigation, and returns to the preset route.

[0075] In summary, the underwater glider for marine observation that can hover at a fixed point can achieve dual-mode operation of long-distance gliding and fixed-point hovering. It is suitable for marine scientific research, underwater facility inspection and environmental monitoring and has broad application prospects.

[0076] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0077] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An underwater glider capable of hovering in a fixed point, characterized in that, It includes a streamlined nacelle, a pump arranged along the longitudinal axis from front to back within the nacelle, a counterweight adjustment assembly, and a vector thruster assembly located outside the nacelle and behind the counterweight adjustment assembly. The counterweight adjustment assembly includes a lead screw and a battery compartment that also serves as a counterweight. The lead screw includes a front threaded section and a rear threaded section with opposite rotation directions. The battery compartment is connected to the rear threaded section via a rear nut seat. In its initial state, the battery compartment is located at the center of gravity of the glider in a horizontal balanced posture. The pump has a water inlet extending out of the hull and its piston rod is connected to the front threaded section via a front nut seat. When the lead screw rotates clockwise, the piston rod moves backward, causing the pump to draw in water and the battery compartment to move forward, thus shifting the glider's center of gravity forward. Conversely, rotating counterclockwise causes the glider's center of gravity to move backward. The vector thruster assembly includes an X-shaped wing that extends outward from the outer side of the cabin and is symmetrically arranged along the width of the glider, and a propeller thruster located at the outer end of each wing. The X-shaped wing provides thrust at a set angle of attack to drive the glider to glide forward. The thrust direction of the thruster is parallel to the longitudinal axis and is used to provide the glider with yaw moment, vertical attitude conversion moment, or hovering buoyancy.

2. The underwater glider capable of hovering at a fixed point according to claim 1, characterized in that, The pump is fixed to the front end of the lead screw and is adjacent to the lead screw. The front threaded section and the rear threaded section are adjacent to each other. The lead of the front threaded section is... The lead of the rear thread segment is The piston rod has a mass of m1, and the battery compartment has a mass of m2. < ; With the lead screw tip as the origin O, the initial coordinate position of the piston rod on the lead screw is: The initial coordinate position of the battery compartment on the lead screw is: If the length of the piston rod is L, then ,in = .

3. The underwater glider capable of hovering at a fixed point according to claim 2, characterized in that, ≤ 。 4. The underwater glider capable of hovering at a fixed point according to claim 3, characterized in that, The cabin is also equipped with a depth gauge for measuring the glider's current depth. When the underwater glider is in a vertical hovering state, its gravity G and the thrust of the propeller are measured. The buoyancy experienced by the glider itself =ρg (t) and environmental disturbances The following force equilibrium equations must be satisfied: +ρg (t)- + =0 in, (t) represents the volume of water displaced by the glider at time t when the piston rod of the pump moves. The resultant force of the thrust from the four propellers, Calculate using the following formula: =K·Δz Where Δz is the depth deviation from the target hovering point, which is measured and fed back by the depth gauge, and K is the proportional coefficient, which is determined by the target buoyancy compensation method.

5. The underwater glider capable of hovering at a fixed point according to claim 4, characterized in that, The magnitude of the gravity G is ,in The min represents the total mass of the glider when the pump is dry. < <max min ,max These represent the minimum and maximum values ​​of the buoyancy force acting on the glider, respectively.

6. The underwater glider capable of hovering at a fixed point according to claim 2, characterized in that, It also includes a drive control assembly located in the cabin. The drive control assembly includes a servo motor, a distributor, a lead screw motor driver, and a navigation controller. The servo motor provides power to the lead screw drive. The lead screw motor driver is used to drive the servo motor to rotate. The lead screw motor driver is connected to the power supply through the distributor. The navigation controller is electrically connected to the lead screw motor driver to control the forward and reverse rotation of the servo motor. The navigation controller is electrically connected to the propeller thruster through an electronic speed controller to control the thrust magnitude and direction of the propeller.

7. The underwater glider capable of hovering at a fixed point according to claim 6, characterized in that, The engine room includes a main engine room tube and a front cover and a rear cover that are respectively sealed and connected to the main engine room tube. The pump is located between the main engine room tube and the front cover, and the drive control assembly is located between the main engine room tube and the rear cover. The main compartment is provided with multiple radial fixing frames spaced apart along the longitudinal axis. Multiple parallel optical axes are provided on the multiple radial fixing frames along the circumferential direction surrounding the lead screw. The extension direction of the optical axes is parallel to the longitudinal axis. The battery compartment is provided with linear bearings that slide with the optical axes. The battery compartment is provided with multiple battery limiting holes. The multiple battery limiting holes are staggered from the linear bearings and are equally spaced along the circumferential direction surrounding the rear nut seat.

8. The underwater glider capable of hovering at a fixed point according to claim 1, characterized in that, The propulsion unit includes a front fairing, a motor mount, a thrust motor, a duct housing, a propeller, and a tail fairing. The propeller is coaxially mounted inside the duct housing. The motor mount is located at the front end of the duct housing. The thrust motor is located inside the motor mount. The propeller extends forward out of the duct housing and is connected to the motor shaft of the thrust motor. The front fairing is fixed to the front end of the motor mount and has a streamlined conical structure for rectifying and guiding water flow into the duct. The tail fairing is fixed to the rear end of the duct housing and serves to rectify and protect the wake.

9. The underwater glider capable of hovering at a fixed point according to claim 1, characterized in that, The outer wall of the battery compartment slides in contact with the inner wall of the cabin, and the cabin is made of thermally conductive material to conduct heat from the battery compartment to the outside.

10. A method for hovering a stationary underwater glider based on claim 6, characterized in that, Includes the following steps: S1. Hovering posture transition, specifically including: S1-1. Control the lead screw to rotate in the forward direction, so that the piston rod moves backward in the pump to make the pump suck water and the battery compartment moves forward in the cabin, so that the center of gravity of the underwater glider moves to the front of the cabin and the bow of the glider tilts downward. S1-2. Drive each propeller to rotate in the same direction and opposite directions on the X-shaped wing to generate thrust, so that the four propellers generate pitching torque, drive the stern of the glider to tilt upward and change the cabin to a vertical attitude. S2. Adjust the center of gravity position and achieve fixed-point hovering, specifically: S2-1. After the glider completes the vertical attitude conversion, the battery compartment moves to the predetermined center of gravity position, and the net buoyancy is adjusted by pumping water in and out or controlling the thrusters to rotate synchronously to drive the glider to the target depth position. S2-2. After the glider reaches the target depth, it first adjusts the net buoyancy by controlling the pump to suck in and drain water, correcting the glider's depth position deviation caused by external disturbance forces, thereby achieving fixed-point hovering. When the deviation cannot be completely corrected by pumping water, the thruster is controlled to rotate synchronously to compensate for the net buoyancy deviation until the fixed-point hovering is maintained.

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