Underwater vehicle control method based on sub-S-surface controller

Abstract

The present invention discloses a method for controlling an underwater vehicle based on a sub-S surface controller. The method comprises the following steps: 1) obtaining deviations of the underwater vehicle's various degrees of freedom as controller inputs; the degrees of freedom include longitudinal, lateral, vertical, pitch, and heading; 2) constructing a sub-S surface controller; and 3) controlling the underwater vehicle's longitudinal, lateral, vertical, pitch, and heading based on the controller's outputs. The present invention utilizes a designed sub-S-shaped function instead of the classic sigmoid function, improving the controller's control response and achieving high-precision motion control.

Description

Technical Field

[0001] The present invention relates to intelligent control technology, and in particular to an underwater vehicle control method based on a sub-S-surface controller. Background Art

[0002] Many intelligent devices operate in harsh underwater environments that are difficult for divers to access. For example, underwater submersibles (SUVs) are playing an increasingly prominent role in detecting wrecked ships and aircraft, inspecting dams, repairing submarine optical cables, and detecting breakpoints in submarine armored cables. Due to the diverse tasks they carry out and the need to carry different sensors and actuators depending on the task, good control performance is a key goal in controller design. As highly nonlinear systems with large inertia and strong correlations, the design of their controllers must focus on control quality.

[0003] Conventional S-surface controllers can better meet the control requirements of general underwater submersible operations, but they do not consider the influence of variable static loads, and there is still room for optimization and improvement in the control effect. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an underwater vehicle control method based on a sub-S-surface controller in response to the defects in the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for controlling an underwater vehicle based on a sub-S surface controller, comprising the following steps:

[0006] 1) Obtain the deviation of each degree of freedom of the underwater vehicle as the input of the controller; the degrees of freedom include longitudinal, lateral, vertical, pitch, and heading;

[0007] 2) Construct a controller based on the sub-S surface, which is expressed as follows:

[0008]

[0009] Among them, u i is the output signal of the controller; i=1,2,3,5,6, respectively representing longitudinal, transverse, vertical, trim, and heading; e i is the input information of the controller, which represents the deviation of the i-th degree of freedom, for e i The rate of change, e i After normalization; k ei for e i The control parameters, for The control parameter, Δu i is the fixed interference force within a certain period of time calculated by the adaptive algorithm;

[0010] is the designed sub-S-type function;

[0011] B is the introduced intelligent integral control item;

[0012] f i is the thrust or torque required for the i-th degree of freedom; f max i is the maximum thrust or torque that can be provided by the i-th degree of freedom, To consider the influence of seawater density change on the residual buoyancy, It is a control term that considers the effect of hull compression deformation on the residual buoyancy;

[0013] 3) According to the output of the controller, the longitudinal, lateral, vertical, pitch and bow direction of the underwater submersible are controlled.

[0014] According to the above scheme, the intelligent integral control item B is designed as follows:

[0015]

[0016] in, is the intelligent integral item, that is, when e j (k) is less than the set threshold, an integral term is introduced. j When (k) is greater than the set threshold, the integral term is canceled. This method can effectively solve the integral saturation phenomenon and effectively eliminate the steady-state error of the control; k Ii is the integral adjustment coefficient.

[0017] According to the above scheme, the control term considering the influence of seawater density change on the residual buoyancy is The design is as follows,

[0018]

[0019] Where ρ is the density of seawater in kg / m 3 ; g is the acceleration due to gravity, in N / kg or m / s 2 ; ▽ is the drainage volume, unit is m 3 ; z1 is the current depth value, z0 is the initial depth value, and the unit of depth is m.

[0020] According to the above scheme, the control term considering the influence of hull compression deformation on the residual buoyancy is The design is as follows,

[0021]

[0022] Where ρ is the density of seawater, in kg / m 3 ; g is the acceleration due to gravity, in N / kg or m / s 2 ; ▽ is the drainage volume, unit is m3 ; z1 is the current depth value, z0 is the initial depth value, the unit of depth is m, α p It is the relative reduction in the volume of the pressure shell when the pressure increases by one unit.

[0023] According to the above scheme, the α p It is expressed as follows:

[0024]

[0025] α p The unit is m 2 / t, where t is 10 3 kg, Z max The maximum diving depth of an underwater submersible.

[0026] The beneficial effects produced by the present invention are:

[0027] 1. The present invention adopts the designed sub-S-type function to replace the classic sigmoid function, which improves the control response of the controller;

[0028] 2. The present invention eliminates the steady-state error of control by introducing an intelligent integral term;

[0029] 3. The present invention takes into account the adaptive regulation of residual buoyancy by changes in seawater density and hull compression deformation, and can achieve high-precision motion control without human intervention even in the presence of current interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0031] Figure 1 is a flow chart of a method according to an embodiment of the present invention;

[0032] Figure 2 It is a motion control simulation curve diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] like Figure 1 As shown, a method for controlling an underwater vehicle based on a sub-S-surface controller includes the following steps:

[0035] 1) Obtain the target value and measured value deviation of each degree of freedom of the underwater vehicle as the input of the controller; the degrees of freedom include longitudinal, lateral, vertical, pitch, and heading;

[0036] 2) Construct a controller based on the sub-S surface, which is expressed as follows:

[0037]

[0038] Among them, u i is the output signal of the controller; i=1,2,3,5,6, respectively representing longitudinal, transverse, vertical, trim, and heading; e i is the input information of the controller, which represents the deviation of the i-th degree of freedom, for e i The rate of change, e i After normalization; k ei for e i The control parameters, for The control parameter, Δu i is the fixed interference force within a certain period of time calculated by the adaptive algorithm;

[0039] is the designed sub-S-type function;

[0040] B is the introduced intelligent integral control item;

[0041] f i is the thrust or torque required for the i-th degree of freedom; f max i is the maximum thrust or torque that can be provided by the i-th degree of freedom, To consider the influence of seawater density change on the residual buoyancy, It is a control term that considers the effect of hull compression deformation on the residual buoyancy;

[0042] The design of intelligent integral control item B is as follows:

[0043]

[0044] in, is the intelligent integral item, that is, when e j (k) is less than the set threshold, an integral term is introduced. j When (k) is greater than the set threshold, the integral term is canceled. This method can effectively solve the integral saturation phenomenon and effectively eliminate the steady-state error of the control; k Ii is the integral adjustment coefficient.

[0045] Control term considering the effect of seawater density changes on residual buoyancy The design is as follows,

[0046]

[0047] Where ρ is the density of seawater, in kg / m 3; g is the acceleration due to gravity, in N / kg or m / s 2 ; ▽ is the drainage volume, unit is m 3 ; z1 is the current depth value, z0 is the initial depth value, and the unit of depth is m.

[0048] Control term considering the effect of hull compression deformation on residual buoyancy The design is as follows,

[0049]

[0050] Among them, α p It is the relative reduction in the volume of the pressure shell when the pressure increases by one unit.

[0051] α p It is expressed as follows:

[0052]

[0053] α p The unit is m 2 / t, where t is 10 3 kg, Z max The maximum diving depth of an underwater submersible.

[0054] 3) Based on the controller output, the underwater vehicle's longitudinal, lateral, vertical, pitch, and heading are controlled. After the control solution is solved, thrust distribution is performed, using a heading-priority thrust distribution strategy to distribute thrust to the actuators that jointly control the propeller thruster and rudder.

[0055] The following simulation experiment is carried out using a submersible as an example. The submersible is equipped with one propeller thruster, one stern horizontal rudder, one stern vertical rudder, and one bow horizontal rudder. The control is performed according to equations (1) to (5), and the control parameter is selected as k e3 =1.15, k I3 =0.6, k e6 =1.10, k I6 =0.7, Z max =200.

[0056] Build a digital simulation platform, set the underwater submersible to be initially stationary at a position of 5m underwater, and there is a current with a velocity of 0.2m / s and a direction of 15°. The control curves of the underwater submersible position and heading angle in this embodiment are as follows: Figure 2This embodiment applies the aforementioned underwater vehicle control method based on a novel sub-S-surface controller. The results show that position and heading angle control are achieved. The control method of the present invention achieves position and heading angle control with essentially no overshoot or oscillation, and achieves depth control accuracy within 0.1 m and heading control accuracy within 0.15°.

[0057] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A method for controlling an underwater vehicle based on a sub-S surface controller, characterized in that: The following steps are involved: 1) Obtain the deviation of each degree of freedom of the underwater vehicle as the input of the controller; the degrees of freedom include longitudinal, lateral, vertical, pitch, and heading; 2) Construct a controller based on the sub-S surface, which is expressed as follows: Among them, u i is the output signal of the controller; i=1,2,3,5,6, respectively representing longitudinal, transverse, vertical, trim, and heading; e i is the input information of the controller, which represents the deviation of the i-th degree of freedom, for e i The rate of change, e i After normalization; k ei for e i The control parameters, for The control parameter, Δu i is the fixed interference force within a certain period of time calculated by the adaptive algorithm; is the designed sub-S-type function; B is the introduced intelligent integral control item; f i is the thrust or torque required for the i-th degree of freedom; f maxi is the maximum thrust or torque that can be provided by the i-th degree of freedom, To consider the influence of seawater density change on the residual buoyancy, It is a control term that considers the effect of hull compression deformation on the residual buoyancy; Among them, the control term considering the influence of hull compression deformation on the residual buoyancy is The design is as follows, Where, ρ is the density of seawater; g is the acceleration due to gravity; is the drainage volume; z1 is the current depth value, z0 is the initial depth value, α p It is the relative reduction in the volume of the pressure shell when the pressure increases by one unit; 3) According to the output of the controller, the longitudinal, lateral, vertical, pitch and bow direction of the underwater submersible are controlled.

2. The underwater vehicle control method based on the sub-S surface controller according to claim 1, characterized in that: The intelligent integral control item B is designed as follows: in, is the intelligent integral item, that is, when e j (k) is less than the set threshold, an integral term is introduced. j When (k) is greater than the set threshold, the integral term is canceled. This method can effectively solve the integral saturation phenomenon and effectively eliminate the steady-state error of the control; k Ii is the integral adjustment coefficient.

3. The underwater vehicle control method based on the sub-S surface controller according to claim 1, characterized in that: The control term considering the effect of seawater density change on the residual buoyancy The design is as follows, Where, ρ is the density of seawater; g is the acceleration due to gravity; is the drainage volume; z1 is the current depth value, and z0 is the initial depth value.

4. The underwater vehicle control method based on the sub-S surface controller according to claim 1, characterized in that: The α p It is expressed as follows: α p The unit is m 2 / t, where t is 10 3 kg, Z max The maximum diving depth of an underwater submersible.

5. An electronic device, characterized in that: include: one or more processors; as well as a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors are enabled to perform the method according to any one of claims 1 to 4.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 4 is implemented.

Images