A Fast Trajectory Tracking Control Method for AUV in Deep-Sea Hydrothermal Vent Areas

Abstract

The present invention relates to the technical field of control of non - electrical variables, and discloses a method for rapid trajectory tracking control of an AUV in a deep - sea hydrothermal vent area, comprising the following steps: S1. Set an expected target, and simultaneously construct a fast non - singular and chattering - free sliding mode surface; S2. Transmit the output information of the sliding mode surface to an adaptive law and a smooth auxiliary dynamic system, and the above - mentioned information is synchronously transmitted to a finite - time trajectory tracking controller. The controller calculates to obtain the thrust that should be provided for each degree of freedom; S3. Perform rudder - propeller coupled thrust allocation according to the "heading optimization" strategy to obtain the thrust that the main propeller should generate and the rudder force that the rudder machine should provide; S4. Send the thrust command to the main propeller in the form of an analog voltage, and send the rudder angle command to the rudder machine in the form of a pulse signal; S5. The propeller and the rudder machine drive the AUV to update the sensor data, compare the actual value with the target value, and determine whether the trajectory tracking control end condition is met.

Description

Technical Field

[0001] The present invention relates to the technical field of non - electrical variable control, and specifically to a method for rapid trajectory tracking control of an AUV in a deep - sea hydrothermal vent area. Background Art

[0002] The deep sea contains rich resources. In addition to mineral resources such as polymetallic nodules and cobalt - rich crusts, there are also energy resources such as combustible ice and oil and gas. Especially the extreme ecological resources in deep - sea hydrothermal vents have important scientific research and application values. The exploration and development of the above - mentioned resources require the assistance of stable deep - sea equipment and reliable detection technologies. The interference and uncertainties caused by the unique terrain, hydrothermal plumes and water environment in the hydrothermal activity area pose higher requirements for the near - bottom trajectory tracking control technology.

[0003] Most of the existing trajectory tracking control methods are based on asymptotically stable control strategies, which can meet the tracking control requirements of general ocean environments. However, these methods have a slow convergence speed, and the robustness to unknown disturbances and parameter uncertainties needs to be further enhanced. In particular, there is less research and it is not deep enough on trajectory tracking operations in deep - sea hydrothermal vent areas. To solve the problems of low tracking accuracy and slow convergence speed of underwater vehicles under the influence of ocean currents and model perturbations, a finite - time method based on terminal sliding mode technology is usually adopted. However, this method cannot overcome the chattering problem of sliding mode and does not consider the actuator saturation factor, resulting in an unstable situation after the tracking error converges. Based on this, the present application proposes a method for rapid trajectory tracking control of an AUV in a deep - sea hydrothermal vent area to solve the above problems. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a method for rapid trajectory tracking control of an AUV in a deep - sea hydrothermal vent area. Based on fully considering the complex terrain and environmental conditions in the deep - sea hydrothermal vent area, a non - singular and non - chattering fast sliding mode surface is constructed, a multi - parameter adaptive law is designed, and a smooth auxiliary dynamic function is introduced to solve the control input saturation phenomenon, so as to solve the problems of low tracking accuracy and slow convergence speed of the AUV system under the influence of ocean currents and model perturbations, and efficiently complete the detection and tracking operation tasks in the deep - sea hydrothermal vent area.

[0006] (2) Technical Solutions

[0007] To achieve the above object, the present invention provides the following technical solutions: A method for rapid trajectory tracking control of an AUV in a deep - sea hydrothermal vent area, including the following steps:

[0008] S1. Set the expected target, that is, the desired trajectory, and at the same time construct a fast non - singular and non - chattering sliding mode surface;

[0009] S2. Transmit the output information of the sliding mode surface to the adaptive law and the smooth auxiliary dynamic system, and synchronously transmit the above information to the finite-time trajectory tracking controller. After the controller performs calculations, the thrusts that should be provided for each degree of freedom are obtained;

[0010] S3. Perform thruster-rudder combined thrust allocation according to the "heading optimization" strategy to obtain the thrust that the main thruster should generate and the rudder force that the rudder machine should provide;

[0011] S4. Send the thrust command to the main thruster in the form of an analog voltage, and send the rudder angle command to the rudder machine in the form of a pulse signal;

[0012] S5. The thruster and the rudder machine drive the AUV to update the sensor data, compare the actual value and the target value, and determine whether the trajectory tracking control end condition is satisfied.

[0013] Preferably, the thrust calculation in step S2 is as follows:

[0014] Construct the trajectory tracking control method shown in formula (1) to achieve fast and precise control:

[0015]

[0016] where, τ c is the AUV finite-time trajectory tracking controller, τ c1 , τ c3 , τ c4 , τ c5 , τ c6 are respectively the longitudinal degree-of-freedom control input, vertical degree-of-freedom control input, surge degree-of-freedom control input, sway degree-of-freedom control input, and heave degree-of-freedom control input after considering thruster saturation; [·] T represents the transpose of the matrix; s l , s γ , s ψ respectively represent the designed sliding mode surfaces of the longitudinal degree of freedom, pitch degree of freedom, and heading degree of freedom; η = [x, y, z, φ, θ, ψ] T , where η represents the position and attitude matrix in the earth coordinate system, that is, the constructed trajectory, x represents the longitudinal position, y represents the lateral position, z represents the vertical position, φ represents the roll angle, θ represents the pitch angle, and ψ represents the heading angle, is the first derivative of η, representing the velocity matrix, is the second derivative of η, representing the acceleration matrix, |·| represents the modulus of the vector; ||·|| represents the Euclidean norm; represents the deviation between the actual output of the actuator and the actuator command; respectively represent the adaptive terms, which are unknown positive numbers; M 11 represents the diagonal element of the first row and the first column of the inertia matrix M; w4 represents a parameter matrix; w 41 is the diagonal element of the first row and first column of w 4 ; w 46 is the diagonal element of the sixth row and sixth column of w 4 ; is a positive constant; J represents the transformation matrix between the body coordinate system and the earth coordinate system; M J represents the nominal term of the inertia matrix M in the earth coordinate system; cos(·) represents the cosine function, sign(·) represents the sign function, τ c_eq represents the output matrix of the trajectory tracking controller, as shown in Equation (2), τ c_n represents the output matrix of the trajectory tracking controller, as shown in Equation (3);

[0017]

[0018] where, w 1 and w 4 represent the parameter matrix; C RBJ represents the nominal term of the centripetal force matrix of the rigid body in the earth coordinate system, C AJ represents the nominal term of the Coriolis force matrix in the earth coordinate system; represents the minimum eigenvalue of the w 1 matrix, s 1 represents the ideal sliding mode surface;

[0019]

[0020] where, B 0 、B 1 、B 2 、B 3 、B 4 and B 5 are positive constants to be designed respectively, used to control the change rate of the adaptive law, δ h is used to match the change rates between the respective adaptive parameters;

[0021]

[0022] In the formula, the parameter χ θ satisfies ω 1 and ω 2 are positive constants and satisfy ω 1 <ω 2 , the bounded function h ω (θ) = 0.5 - 0.5sin(L θ (θ)),

[0023]

[0024] Among them, C 1 and C 2 , α 1 , α 2 are constants, α 3 = 1, α ∈ (0, 1);

[0025] After the control solution is calculated, a heading - first strategy is adopted for thrust allocation.

[0026] The above - mentioned method of the present invention can be applied to the trajectory tracking operation of an underwater vehicle in a deep - sea hydrothermal vent area.

[0027] (III) Beneficial effects

[0028] Compared with the prior art, the present invention provides a method for rapid trajectory tracking control of an AUV in a deep - sea hydrothermal vent area, having the following beneficial effects:

[0029] 1. In the method for rapid trajectory tracking control of an AUV in a deep - sea hydrothermal vent area, under the full consideration of the complex terrain and environmental conditions in the deep - sea hydrothermal vent area, a non - singular and non - chattering fast sliding mode surface is adopted to effectively eliminate the chattering problem of sliding mode control, a multi - parameter adaptive law is adopted to improve the problem of slow convergence speed, and a smooth auxiliary dynamic function is adopted to solve the control input saturation phenomenon, so as to improve the trajectory tracking control accuracy;

[0030] 2. The method for rapid trajectory tracking control of an AUV in a deep - sea hydrothermal vent area can effectively resist the interference caused by the complex three - dimensional flow field formed by vertical plume currents and horizontal currents. The control process does not require manual intervention, and can achieve high - precision trajectory tracking and near - bottom detection tasks. The depth tracking accuracy can reach within 0.03 m, the heading tracking accuracy can reach within 0.2°, and the longitudinal speed tracking accuracy can reach within 0.05 m / s. Description of the drawings

[0031] Figure 1 is the trajectory tracking control flow chart of the present invention;

[0032] Figure 2 is the target expected detection trajectory model of the present invention with hydrothermal interference;

[0033] Figure 3 is the AUV trajectory tracking pool test curve graph of the present invention. Specific implementation manners

[0034] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] Please refer to Figure 1 , a method for rapid trajectory tracking control of an AUV in a deep-sea hydrothermal vent area, comprising the following steps:

[0036] S1. Set the expected target, that is, the desired trajectory, and simultaneously construct a fast non-singular and non-chattering sliding mode surface;

[0037] S2. Transmit the output information of the sliding mode surface to the adaptive law and the smooth auxiliary dynamic system, and synchronously transmit the above information to the finite-time trajectory tracking controller. After the controller performs calculations, the thrust that should be provided for each degree of freedom is obtained;

[0038] S3. Perform rudder and propeller combined thrust distribution according to the "heading optimization" strategy to obtain the thrust that the main propeller should generate and the rudder force that the rudder should provide;

[0039] S4. Send the thrust command to the main propeller in the form of an analog voltage, and send the rudder angle command to the rudder in the form of a pulse signal;

[0040] S5. The propeller and the rudder drive the AUV to update the sensor data, compare the actual value and the target value, and determine whether the trajectory tracking control end condition is satisfied.

[0041] Among them, the thrust calculation in step S2 is as follows:

[0042] Construct the trajectory tracking control method shown in formula (1) to achieve fast and precise control:

[0043]

[0044] Among them, τ c is the AUV finite-time trajectory tracking controller, τ c1 , τ c3 , τ c4 , τ c5 , τ c6 are respectively the longitudinal degree-of-freedom control input, vertical degree-of-freedom control input, surge degree-of-freedom control input, sway degree-of-freedom control input, and heave degree-of-freedom control input after considering the saturation of the propeller; [·] T represents the transpose of the matrix; s l , s γ , s ψSliding mode surfaces respectively representing the longitudinal degree of freedom, trim degree of freedom, and heading degree of freedom of the design; η = [x, y, z, φ, θ, ψ] T , where η represents the position and attitude matrix in the earth coordinate system, that is, the constructed trajectory, x represents the longitudinal position, y represents the lateral position, z represents the vertical position, φ represents the roll angle, θ represents the pitch angle, and ψ represents the heading angle, is the first derivative of η, representing the velocity matrix, is the second derivative of η, representing the acceleration matrix, |·| represents the modulus of a vector; ||·|| represents the Euclidean norm; represents the deviation between the actual output of the actuator and the actuator command; respectively represent the adaptive terms, which are unknown positive numbers; M 11 represents the diagonal element of the first row and first column of the inertia matrix M; w 4 represents a parameter matrix; w 41 is the diagonal element of the first row and first column of w 4 , w 46 is the diagonal element of the sixth row and sixth column of w 4 ; is a positive constant; J represents the transformation matrix between the body coordinate system and the earth coordinate system; M J represents the nominal term of the inertia matrix M in the earth coordinate system; cos(·) represents the cosine function, sign(·) represents the sign function, τ c_eq represents the output matrix of the trajectory tracking controller, as shown in Equation (2), τ c_n represents the output matrix of the trajectory tracking controller, as shown in Equation (3);

[0045]

[0046] Among them, w 1 and w 4 represent the parameter matrix; C RBJ represents the nominal term of the rigid body centripetal force matrix in the earth coordinate system, C AJ represents the nominal term of the Coriolis force matrix in the earth coordinate system; represents the minimum eigenvalue of the w 1 matrix, s 1 represents the ideal sliding mode surface;

[0047]

[0048] Among them, B 0 , B 1 , B 2 , B 3 , B 4 and B 5are respectively positive constants to be designed, used to control the change rate of the adaptive law, δ h is used to match the change rates between respective adaptive parameters;

[0049]

[0050] In the formula, parameter χ θ satisfies ω 1 and ω 2 are positive constants and satisfy ω 1 <ω 2 , bounded function h ω (θ) = 0.5 - 0.5sin(L θ (θ)),

[0051]

[0052] Among them, C 1 , C 2 , α 1 , α 2 are constants, α 3 = 1, α ∈ (0, 1);

[0053] After the control solution, a strategy of giving priority to the heading direction is adopted for thrust allocation.

[0054] The above method of the present invention can be applied to the trajectory tracking operation of an underwater vehicle in a deep - sea hydrothermal vent area.

[0055] Taking the trajectory tracking control of a certain type of AUV as an example, a pool experiment is carried out. Please refer to Figure 2 , Figure 2 is the expected detection trajectory model of the target hydrothermal vent area. According to the expected detection trajectory, the AUV starts from the release point, ascends over a pile, then dives, passes through a dense area of hydrothermal deposits, and then ascends to spiral around and detect above the active hydrothermal vent.

[0056] It is set that the initial speed of the underwater vehicle is 0 m / s, the initial heading angle is 86°, and the initial depth is 0 m. The ocean current interference in the hydrothermal activity area is set as follows: at a height of 5 m from the vent, the vertical ocean current value is distributed in a Gaussian shape along the radial direction, and the maximum value is 0.5 m / s. There is a horizontal ocean current in the deep - sea hydrothermal vent area, the water flow velocity is 2.1 cm / s, and the direction is 29°.

[0057] During the experiment, the initial pose of the AUV is η(0) = [161 m, - 52.5 m, 0 m, 0 rad, 0 rad, 3.054 rad] T and the initial speed is 0 m / s. The maximum output of the actuator is τ max= [±145N, 0N, ±80N, ±39N.m, ±58N.m, ±59N.m] T 。The main control parameters of the trajectory tracking algorithm are as follows: C 1 = 1, C 2 = 4, w 1 = diag(1.2, 1.02, 1.6, 1.02, 1.02, 1.02), w 2 = 0.2diag(2.1, 2, 2.7, 1.8, 2.5, 2.6), ω 1 = 0.001, ω 2 = 0.2, w 3 = 3, w 4 = 0.08diag(0.1, 0.2, 1, 1, 1, 1), δ h = 0.006, B 0 = 0.1, B 1 = 0.05, B 2 = 5, B 3 = 7, B 4 = 1, B 5 = 0.01.

[0058] The controller is composed as follows:

[0059]

[0060]

[0061] The combined thrust distribution of the propeller and rudder is carried out by using the heading optimization strategy. Assume that the arm of force of the main thruster relative to the center of the hull is l 1 , and the generated thrust is F 1 ; the arm of force of the rudder relative to the center of the hull is l 2 , and the generated lift force is F 2L , and the generated drag force is F 2D ; the arm of force of the elevator relative to the center of the hull is l 3 , and the generated lift force is F 3L , and the generated drag force is F 3D , then the thrust distribution is shown in Equation (12):

[0062]

[0063] Please refer to Figure 3 , Figure 3This is the curve graph of the AUV trajectory tracking pool test. Based on the deep-sea hydrothermal vent area AUV fast trajectory tracking control method of the present invention, it reflects the anti-interference ability against the complex three-dimensional flow field formed by vertical plume currents and horizontal currents, with high-precision trajectory tracking and fast response. The depth tracking accuracy can reach within 0.03 m, the heading tracking accuracy can reach within 0.2°, and the longitudinal speed tracking accuracy can reach within 0.05 m / s, which can meet the requirements of deep-sea hydrothermal vent area exploration tasks.

[0064] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for fast trajectory tracking and control of AUV in deep-sea hydrothermal areas, characterized in that: The following steps are involved: S1, set the expected target, i.e. the expected trajectory, and construct a fast non-singular non-buffering sliding surface; S2, the output information of the sliding surface is transmitted to the adaptive law and the smooth auxiliary dynamic system, and the above information is synchronously transmitted to the finite time trajectory tracking controller, and the controller obtains the thrust that each degree of freedom should provide after solving; S3. According to the "heading optimization" strategy, the thrust of the rudder-propeller linkage is distributed to obtain the thrust that the main propeller should generate and the rudder force that the steering gear should provide; S4, sending the thrust command to the main thruster in the form of analog voltage, and sending the rudder angle command to the steering gear in the form of pulse signal; S5, the thruster and the steering gear drive the AUV to update the sensor data, compare the actual value with the target value, and determine whether the trajectory tracking control end condition is met.

2. A deep-sea hydrothermal area AUV fast trajectory tracking control method according to claim 1, characterized in that: The thrust calculation in step S2 is as follows: The trajectory tracking control method shown in equation (1) is constructed to achieve fast and accurate control: Among them, τ c is the AUV finite-time trajectory tracking controller, τ c1 , τ c3 , τ c4 , τ c5 , τ c6 are the longitudinal degree of freedom control input, vertical degree of freedom control input, surge degree of freedom control input, sway degree of freedom control input and heave degree of freedom control input after considering thruster saturation respectively; [·] T represents the matrix rank; s l 、s γ 、s ψ The sliding surfaces represent the designed longitudinal degrees of freedom, trim degrees of freedom and heading degrees of freedom respectively; η=[x,y,z,φ,θ,ψ] T , where η represents the position and attitude matrix in the geodetic coordinate system, that is, the constructed trajectory, x represents the longitudinal position, y represents the lateral position, z represents the vertical position, φ represents the heel angle, θ represents the pitch angle, and ψ represents the heading angle. is the first-order derivative of η, representing the velocity matrix, is the second-order derivative of η, represents the acceleration matrix, |·| represents the modulus of the vector; ||·|| represents the Euclidean norm; Indicates the deviation between the actual output of the actuator and the actuator command; Respectively represent adaptive terms, which are unknown positive numbers; M 11 represents the diagonal element of the first row and first column of the inertia matrix M; w4 represents a parameter matrix; w 41 is the diagonal element of row 1 and column 1 of w4, w 46 It is the diagonal element at row 6 and column 6 of w4; is a positive constant; J represents the transformation matrix between the hull coordinate system and the earth coordinate system; M J represents the nominal term of the inertia matrix M in the geodetic coordinate system; cos(·) represents the cosine function, sign(·) represents the sign function, τ c_eq represents the trajectory tracking controller output matrix, as shown in formula (2), τ c_n represents the trajectory tracking controller output matrix, as shown in formula (3); Among them, w1 and w4 represent parameter matrices; C RBJ represents the nominal term of the rigid body centripetal force matrix in the geodetic coordinate system, C AJ represents the nominal term of the Coriolis force matrix in the geodetic coordinate system; represents the minimum characteristic root of w1 matrix, s1 represents the ideal sliding surface; in, B0, B1, B2, B3, B4 and B5 are positive constants to be designed, which are used to control the speed of change of the adaptive law. h It is used to match the change rate between various adaptive parameters; In the formula, the parameter χ θ satisfy ω1 and ω2 are positive constants and satisfy ω1<ω2, bounded function Among them, C1, C2, α1, α2 are constants, α3=1, α∈(0,1); After the control solution is calculated, the thrust is distributed with the heading priority strategy.

3. Application of the method according to any one of claims 1 or 2 in trajectory tracking operations of underwater submersibles in deep-sea hydrothermal areas.

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