Automatic compensation method for underwater buoyancy of AUV (Autonomous Underwater Vehicle)

Abstract

The invention provides an automatic compensation method for underwater buoyancy of an AUV (Autonomous Underwater Vehicle), which meets the navigation depth control requirement caused by the change of seawater density in the navigation process of the underwater vehicle. Comprising the following steps: step 1, acquiring seawater temperature, salinity and navigation depth data of a current sea area; 2, according to the obtained seawater temperature, salinity and navigation depth data, the seawater density rho1 of the position where the AUV is located is calculated, and meanwhile the current liquid level of an AUV buoyancy adjusting device is collected through a liquid level sensor; 3, calculating the weight M1 of the AUV according to the seawater density rho1 and the volume V of the AUV, and comparing the weight M1 with the initial weight M0 to obtain weight change; 4, after the water amount of the AUV is adjusted, a proper liquid level value H1 is obtained, and the AUV stores the liquid level value to serve as the balance liquid level for depth control during underwater navigation of the AUV.

Description

Technical Field

[0001] The invention relates to the technical field of AUV (autonomous underwater unmanned vehicle) control, and in particular to an automatic underwater buoyancy compensation method for an AUV. Background Art

[0002] With the development of unmanned technology, AUV equipment has been widely used in various underwater fields, especially in underwater detection, military reconnaissance and other fields. When AUV performs tasks in different sea areas, the buoyancy of AUV changes due to different seawater densities, which brings uncertain risks to AUV navigation control. Especially when the seawater density changes greatly, the AUV navigation depth control may become unstable.

[0003] When the AUV performs a diving mission or operates at different depths, the buoyancy will change with the depth. This is mainly caused by the inconsistency between the physical parameters of the AUV and the seawater (for example, volume compression rate and temperature shrinkage rate). In order to successfully complete the navigation at different depths on the surface and underwater, the Autosub AUV is equipped with a passive buoyancy compensation system in the prior art. The system consists of three parts: a low-pressure air compensator, an oil bag, and a high-pressure air compensator. It can use the pressure of seawater to achieve passive compensation of buoyancy when the depth changes, and allow the AUV to have a certain positive buoyancy when sailing on the surface to ensure communication quality. For example:

[0004] The "Qianlong No. 1" deep-sea AUV developed by the Shenyang Institute of Automation under the Chinese Academy of Sciences is equipped with a one-way buoyancy adjustment system driven by seawater pressure, which achieves the purpose of diving without balancing during deep-diving exploration. However, in general, passive buoyancy compensation is only used for buoyancy compensation in the deepening process, and the design of the compensation system requires known hydrological information at different depths of the test waters. Therefore, it is difficult to achieve accurate buoyancy compensation, which limits its use. Summary of the invention

[0005] The present invention proposes an automatic underwater buoyancy compensation method for an AUV, which realizes the navigation depth control requirement caused by the change of seawater density during the navigation of the underwater vehicle.

[0006] The present invention is achieved through the following technical solutions.

[0007] An automatic buoyancy compensation method for an AUV comprises the following steps:

[0008] Step 1: Obtain the current sea water temperature, salinity and navigation depth data;

[0009] Step 2: Calculate the seawater density ρ1 at the location of the AUV based on the acquired seawater temperature, salinity and navigation depth data, and collect the current liquid level of the AUV buoyancy adjustment device through the liquid level sensor;

[0010] Step 3: Calculate the weight M1 of the AUV based on the seawater density ρ1 and the volume V of the AUV, and compare it with the initial weight M0 to obtain the weight change;

[0011] Step 4: After adjusting the water volume of the AUV, a suitable liquid level value H1 is obtained, and the AUV saves the liquid level value as the equilibrium liquid level for depth control when the AUV navigates underwater.

[0012] Beneficial effects of the present invention:

[0013] 1. The present invention collects seawater temperature, salinity and navigation depth data during AUV navigation in real time, calculates the buoyancy change of AUV caused by the change of seawater density, and adjusts the water volume of AUV to obtain a suitable equilibrium liquid level during AUV navigation;

[0014] 2. The present invention has the function of compensating for the buoyancy changes caused by the changes in seawater density in real time. When the AUV is performing a long-distance cross-sea mission or the density of the navigation area changes sharply, the mission can be performed normally without interruption of the mission or the AUV sinking to the bottom due to the change in seawater density.

[0015] 3. The present invention reduces the risk of instability in AUV navigation depth control and improves control efficiency and navigation safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of an automatic AUV underwater buoyancy compensation method. DETAILED DESCRIPTION

[0017] The exemplary embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the accompanying drawings are only exemplary and are intended to illustrate the principles and spirit of the present invention, rather than to limit the scope of the present invention.

[0018] like Figure 1 As shown, an automatic buoyancy compensation method for an AUV of the present invention specifically comprises the following steps:

[0019] Step 1: Obtain the current sea water temperature, salinity and navigation depth data;

[0020] During specific implementation, the AUV's external temperature, salinity and depth detection sensors are used to detect the seawater temperature, salinity and navigation depth data at the location in real time.

[0021] Step 2: Calculate the seawater density ρ1 at the location of the AUV based on the acquired seawater temperature, salinity and navigation depth data, and collect the current liquid level of the AUV buoyancy adjustment device through the liquid level sensor;

[0022] Step 3: Calculate the weight M1 of the AUV based on the seawater density ρ1 and the volume V of the AUV, and compare it with the initial weight M0 to obtain the weight change;

[0023] In specific implementation, when the weight increases, the amount of water in the AUV water storage tank is increased by injecting water, thereby increasing the negative buoyancy of the AUV; when the weight decreases, the amount of water in the AUV water storage tank is reduced by draining water, thereby increasing the positive buoyancy of the AUV.

[0024] Step 4: After adjusting the water volume of the AUV, a suitable liquid level value H1 is obtained, and the AUV saves the liquid level value as the equilibrium liquid level for depth control when the AUV navigates underwater.

[0025] In this embodiment, when changes in the temperature and salinity of the seawater are detected during the navigation of the AUV, the density changes to ρ1. The weight M1 of the AUV can be calculated by the formula: M1=ρ1*V. The weight change value of the AUV is obtained by comparing M1 with MO, and the water volume change value is further obtained. The buoyancy of the AUV is changed by adjusting the water volume.

[0026] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0027] It is obvious to those skilled in the art that the embodiments of the present invention are not limited to the details of the above exemplary embodiments, and that the embodiments of the present invention can be implemented in other specific forms without departing from the spirit or basic features of the embodiments of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the embodiments of the present invention is limited by the attached claims rather than the above description, so it is intended to include all changes that fall within the meaning and scope of the equivalent elements of the claims in the embodiments of the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units, modules or devices stated in the system, device or terminal claims can also be implemented by the same unit, module or device through software or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.

[0028] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solutions of the embodiments of the present invention and are not intended to limit them. Although the embodiments of the present invention have been described in detail with reference to the above preferred implementation modes, those skilled in the art should understand that the technical solutions of the embodiments of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic underwater buoyancy compensation method for AUV, characterized in that: The following steps are involved: Step 1: Obtain the current sea water temperature, salinity and navigation depth data; Step 2: Calculate the seawater density ρ1 at the location of the AUV based on the acquired seawater temperature, salinity and navigation depth data, and collect the current liquid level of the AUV buoyancy adjustment device through the liquid level sensor; Step 3: Calculate the weight M1 of the AUV based on the seawater density ρ1 and the volume V of the AUV, and compare it with the initial weight M0 to obtain the weight change; Step 4: After adjusting the water volume of the AUV, a suitable liquid level value H1 is obtained, and the AUV saves the liquid level value as the equilibrium liquid level for depth control when the AUV navigates underwater.

2. The automatic buoyancy compensation method for an AUV as claimed in claim 1, characterized in that: The AUV's external temperature, salinity and depth detection sensors are used to detect the seawater temperature, salinity and navigation depth data at the location in real time.

3. A method for automatic underwater buoyancy compensation of an AUV as claimed in claim 1 or 2, characterized in that: When the weight increases, the amount of water in the AUV water storage tank is increased by injecting water, thereby increasing the negative buoyancy of the AUV.

4. A method for automatic underwater buoyancy compensation of an AUV as claimed in claim 1 or 2, characterized in that: When the weight is reduced, the amount of water in the AUV water storage tank is reduced by draining water, thereby increasing the positive buoyancy of the AUV.

5. The automatic underwater buoyancy compensation method of an AUV according to claim 1 or 2, characterized in that: The M1 is calculated by the following formula: M1=ρ1*V.

Images