AUV depth-keeping suspension control method of oil bag type buoyancy adjusting device

Abstract

The invention relates to the technical field of AUV control, in particular to an AUV depthkeeping suspension control method of an oil bag type buoyancy adjusting device, depth adjustment is achieved through the volume change of an outer oil bag, the volume change of the outer oil bag is related to the internal oil amount, and the outer oil bag is filled with oil or pumped to achieve floating and diving of the AUV. According to the method, the maneuvering capability of the AUV with the device can be effectively improved, and the use scene is expanded.

Description

Technical Field

[0001] The present invention relates to the field of AUV control technology, and specifically relates to a method for controlling the constant-depth suspension of an AUV using an oil-bag type buoyancy regulating device. Background Art

[0002] Depth-fixed suspension of underwater unmanned vehicles (AUVs) is depth control without speed, which requires the vehicle to be able to hover without power at a certain depth and achieve virtual anchoring to meet special mission needs.

[0003] Common AUV depth-fixed suspension implementation methods include vertical thrust and buoyancy adjustment device. Vertical thrust adjusts depth changes by controlling the thrust output of the propeller in the vertical direction; buoyancy adjustment device adjusts depth by changing the AUV's own weight or displacement volume. Compared with vertical thrust, the buoyancy adjustment device does not need to be in working state for a long time when the depth changes. The system is more energy-efficient and more suitable for depth adjustment needs at great depths, so it has been widely used on AUVs.

[0004] The oil bladder buoyancy regulating device achieves depth change by changing the drainage volume of the oil bladder. It is usually composed of an outer oil bladder and an inner oil bladder. The outer oil bladder is exposed to the water, and the inner oil bladder is placed in the cabin to store oil. The amount of oil in each bladder is changed by a plunger pump. The more oil is injected into the outer oil bladder, the larger the volume, and the greater the buoyancy generated. However, due to the flow rate of the plunger pump, the change in the volume of the oil bladder is slow, so the buoyancy change is also relatively slow. When used for fixed depth control, the vertical force cannot be changed in time, and there is a lag in the control response, which is not suitable for conventional control methods. Summary of the invention

[0005] In view of the deficiencies in the prior art, an object of the present invention is to provide a method for controlling the constant depth suspension of an AUV with an oil bladder type buoyancy regulating device.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for controlling the AUV fixed depth suspension of an oil bladder type buoyancy regulating device, the steps of which are:

[0007] (1) A buoyancy adjustment compartment is provided at the midship position of the AUV, and the compartment contains an oil bag type buoyancy adjustment device;

[0008] (2) The oil bladder type buoyancy control device is mainly composed of an outer oil bladder, an inner oil bladder, a plunger pump, and a pump motor. The outer oil bladder is at the wet end, and the inner oil bladder, the plunger pump, and the pump motor are at the dry end. The plunger pump is used to adjust the oil volume change between the outer oil bladder and the inner oil bladder.

[0009] (3) The host computer sends a depth command H to the AUV c , the AUV determines whether to dive or surface according to the current depth H0, pumping oil from the external oil bag when diving, and pumping oil into the external oil bag when surfacing;

[0010] (4) Formulate a segmented oil volume adjustment strategy based on the depth error ΔH;

[0011] (5) Assume that the AUV needs to dive to H c , set the dividing line H c -a and H c +a;

[0012] (6) The diving depth is less than H c At -a, the outer oil bag discharges oil to accelerate the dive;

[0013] (7) Depth at H c -a and H c +a, it enters the speed control stage, and the external oil bag frequently pumps oil according to the diving speed to control the diving speed within the set range;

[0014] (8) Depth greater than H c At +a, the outer oil bag is filled with oil to accelerate the floating stage;

[0015] (9) Finally, the AUV fluctuates around the set depth value and continues to converge to the set value.

[0016] In some of the embodiments, the segmented oil quantity adjustment strategy is to set different diving depths and diving speed intervals during the diving process, and determine the change in the oil quantity in the oil bag according to the interval.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention realizes the fixed-depth suspension control of AUV through the oil-bag buoyancy adjustment device, improves the underwater maneuverability of AUV, and expands the application scenarios of AUV.

[0019] 2. While realizing the AUV fixed-depth suspension control, the present invention effectively reduces the power consumption of the equipment required for the maneuver compared to vertical thrust. The AUV can effectively extend the operation time or improve the endurance when performing such a fixed-depth mission.

[0020] Details of one or more embodiments of the present application are presented in the following drawings and descriptions to make other features, purposes and advantages of the present application more concise and easy to understand. The present application is fully described and understood through the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structural design of the oil bag type buoyancy regulating device;

[0022] Figure 2 is a schematic diagram of the buoyancy adjustment device working in depth;

[0023] Figure 3 It is a schematic diagram of the fuzzy depth control algorithm framework of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See also Figure 1-3 The present invention provides a technical solution: a method for controlling the AUV fixed depth suspension of an oil bag type buoyancy regulating device, comprising the following contents:

[0026] (1) The buoyancy adjustment mechanism is mainly composed of an outer oil bag, an inner oil bag, a bidirectional plunger pump, a solenoid valve, a liquid level sensor and a control panel;

[0027] (2) The external oil bladder is at the wet end and is immersed in water when in use; except for the external oil bladder, the rest of the parts are in the sealed cabin;

[0028] (3) The outer and inner oil sacs are both in a vacuum state, and the volume change is related to the amount of oil in them;

[0029] (4) The bidirectional plunger pump and pump motor support forward and reverse rotation, and can pump oil in different directions according to instructions; the flow rate of the plunger pump remains consistent during operation, and the flow rate is not affected by forward and reverse rotation;

[0030] like Figure 2 As shown, the oil bladder type buoyancy regulating device mentioned in the present invention works in a deeper state, corresponding to step (3). When the AUV floats up, the solenoid valve opens, and the plunger pump starts to work to inject oil from the inner oil bladder into the outer oil bladder, so that the volume of the outer oil bladder increases and the buoyancy increases; when diving, the plunger pump pumps oil from the outer oil bladder back to the inner oil bladder, and the volume of the outer oil bladder decreases, and the buoyancy also decreases accordingly.

[0031] like Figure 3 As shown, the fuzzy depth control algorithm framework of the buoyancy regulating device designed by the present invention corresponds to steps (4)-(9), and its specific method is as follows:

[0032] (1) The host computer sends the expected depth command H c , set the depth boundary H c -a and H c +a, where a is between 1 and H c Between, usually within 20, H c The larger the value, the larger a is. The specific value can be determined based on the results of multiple fixed-depth tests.

[0033] (2) When the depth difference ΔH>a, the AUV is in the accelerated diving stage, and the buoyancy control device continues to pump oil from the external oil bag;

[0034] (3) When the depth difference 0<ΔH<a, the AUV enters the speed-controlled diving stage and controls the diving speed w: w>v h When the outer oil bag is pumped with oil, the buoyancy is increased and the diving speed is slowed down; 0<w<v h When w≤0, the device stops working; when w≤0, the oil is pumped out from the outer oil bag to make it continue to dive; h ∈(0.01,0.1), the specific value can be determined according to the test results;

[0035] (4) When the depth difference -a<ΔH<0, the diving depth has exceeded the set value and enters the speed-controlled ascent stage: w≤-v h When w≥0, the outer oil bag is pumped to prevent the dive; -v h When <w<0, the device stops working;

[0036] (5) When the depth difference ΔH < -a, the AUV enters the accelerated ascent stage, and the device continues to pump oil into the external oil bag to increase the buoyancy and make it float;

[0037] (6) Ideally, the AUV will eventually fluctuate around the desired depth value and eventually approach the set value.

[0038] Through this technical solution, by setting different diving depth intervals and diving speeds, the oil bag volume change is continuously adjusted, and finally the dynamic depth setting of the AUV is achieved. The present invention effectively improves the maneuverability of the AUV with such a buoyancy adjustment device and expands the actual application scenarios of the AUV.

[0039] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

[0040] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the constant depth suspension of an AUV with an oil bladder type buoyancy regulating device, characterized in that: The steps are: (1) A buoyancy adjustment compartment is provided at the midship position of the AUV, and the compartment contains an oil bag type buoyancy adjustment device; (2) The oil bladder type buoyancy control device is mainly composed of an outer oil bladder, an inner oil bladder, a plunger pump, and a pump motor. The outer oil bladder is at the wet end, and the inner oil bladder, the plunger pump, and the pump motor are at the dry end. The plunger pump is used to adjust the oil volume change between the outer oil bladder and the inner oil bladder. (3) The host computer sends a depth command H to the AUV c , the AUV determines whether to dive or surface according to the current depth H0, pumping oil from the external oil bag when diving, and pumping oil into the external oil bag when surfacing; (4) Formulate a segmented oil volume adjustment strategy based on the depth error ΔH; (5) Assume that the AUV needs to dive to H c , set the dividing line H c -a and H c +a; (6) The diving depth is less than H c At -a, the outer oil bag discharges oil to accelerate the dive; (7) Depth at H c -a and H c +a, it enters the speed control stage, and the external oil bag frequently pumps oil according to the diving speed to control the diving speed within the set range; (8) Depth greater than H c At +a, the outer oil bag is filled with oil to accelerate the floating stage; (9) Finally, the AUV fluctuates around the set depth value and continues to converge to the set value.

2. The method for controlling the AUV constant depth suspension of an oil bladder type buoyancy regulating device according to claim 1, characterized in that: The segmented oil quantity adjustment strategy is to set different diving depths and diving speed intervals during the diving process, and determine the change in the oil quantity in the oil bag according to the interval.

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