Robust rapid tracking control method and system for underwater unmanned vehicle

Abstract

The invention discloses a robust rapid tracking control method and system for an underwater unmanned vehicle. The method comprises the following steps: constructing a nonlinear kinematics model, a dynamics model and a tracking error dynamics model of an under-actuated underwater unmanned vehicle; designing a sliding-mode observer for interference estimation according to the nonlinear dynamic model of the under-actuated underwater unmanned vehicle; and designing a robust nonlinear fast feedback control law to realize fast and accurate tracking control of the under-actuated unmanned underwater vehicle. According to the method provided by the invention, the fixed time convergence characteristic of an under-actuated underwater unmanned vehicle tracking control system is ensured, the limitation of a traditional method and a finite time method is effectively overcome, that is, the method depends too much on the size of the initial state of the system, and finally, rapid and accurate tracking of the reference trajectory by the underwater unmanned vehicle is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater unmanned vehicle control, and in particular relates to a robust and rapid trajectory tracking control method and system for an underwater unmanned vehicle. Background Art

[0002] With the continuous development of underwater unmanned system technology, underwater unmanned vehicles have been increasingly used to perform various high-risk marine operation scenarios, covering civilian fields such as oil and gas resource exploration and development, submarine pipeline inspection, ocean surveying and mapping, deep-sea archaeology, as well as military applications such as battlefield reconnaissance, covert strikes, and mine countermeasures, showing significant application value in both military and civilian fields.

[0003] Precise tracking control is the core technical requirement to ensure that UUVs can perform the above tasks. In the process of performing the above tasks, underwater unmanned vehicles are usually required to have good trajectory tracking performance. However, the dynamic model of underwater unmanned vehicles has multivariable, highly nonlinear, strongly coupled and uncertain characteristics, coupled with the influence of time-varying disturbances that are difficult to measure in the marine environment, making the trajectory tracking control of underwater unmanned vehicles challenging. In addition, when underwater unmanned vehicles perform trajectory tracking, the convergence time of the system state error is a relatively important indicator, which directly affects the speed of tracking. Although traditional control methods can achieve infinite time stability, they cannot meet the fast convergence requirements of real-time operations. Although the recently developed finite-time control theory has made breakthroughs in convergence time, studies have shown that its convergence time is significantly correlated with the initial state of the system, resulting in the convergence performance in actual engineering applications still being limited. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a robust and fast tracking control method and system for an underwater unmanned vehicle, and in particular relates to a robust and fast tracking control method, system, medium, equipment and terminal for an underactuated underwater unmanned vehicle.

[0005] The present invention is implemented as follows: a robust and fast tracking control method and system for an underwater unmanned vehicle includes: constructing a nonlinear kinematic model, a dynamic model, and a tracking error dynamic model of an under-actuated underwater unmanned vehicle; designing a fast disturbance observer based on the nonlinear dynamic model of the under-actuated underwater unmanned vehicle to perform real-time disturbance estimation; and designing a robust nonlinear fast feedback control law for the under-actuated underwater unmanned vehicle based on the disturbance estimation results to achieve fast and precise tracking control of the underwater unmanned vehicle.

[0006] Furthermore, the robust fast tracking control method for underwater unmanned vehicle includes the following steps:

[0007] Step 1: Analyze the influence of wave and current environment interference and establish the nonlinear kinematic and dynamic model of the underactuated underwater unmanned vehicle;

[0008] Step 2: Based on the error coordinate transformation, the underwater unmanned vehicle tracking error dynamics model is established;

[0009] Step 3: Design a sliding mode disturbance observer to estimate the unknown time-varying environmental disturbance online, obtain the disturbance estimate, and use the disturbance estimate as a feedback signal in the outer loop control link;

[0010] Step 4: Design a robust backstepping fast feedback control law to enable the underactuated underwater unmanned vehicle to accurately track the reference trajectory.

[0011] Furthermore, the nonlinear kinematic model of the underactuated underwater unmanned vehicle in step 1 is:

[0012]

[0013] The dynamic model of the underactuated underwater unmanned vehicle is:

[0014]

[0015] Where [x, y, z] and [θ, ψ] represent the position and orientation of the underwater unmanned vehicle, [u, v, w] and [q, r] represent the linear velocity and angular velocity of the underwater unmanned vehicle, respectively. u ,τ q ,τ r ] is the control input of the underwater unmanned vehicle's longitudinal u, pitch q and heading r, τ di (i=1,2,3,5,6) represents unknown time-varying environmental interference, m ii represents the mass and inertia parameters of the underwater unmanned vehicle, d ii represents the damping term; for the unknown positive constant δ i , there exists |τ di |≤δ i .

[0016] Furthermore, the establishment of the underwater unmanned vehicle tracking error dynamics model based on error coordinate transformation in step 2 includes:

[0017] Convert the position error in the earth coordinate system to the hull coordinate system:

[0018]

[0019] In the formula, [x d ,y d ,z d ] represents the smooth reference trajectory, J(η) represents the rotation matrix, which is defined as:

[0020]

[0021] Construct the distance error variable ρ between the underwater unmanned vehicle and the reference trajectory point e (t) and the azimuth error variable [χ e (t),γ e (t)] is:

[0022]

[0023] The derivative of the position error expression in the hull coordinate system can be obtained:

[0024]

[0025] Where,

[0026] By differentiating the distance error variable and orientation error variable expressions between the underwater unmanned vehicle and the reference trajectory point, the tracking error dynamics model of the underactuated underwater unmanned vehicle can be obtained as follows:

[0027]

[0028] Furthermore, the sliding mode disturbance observer designed in step 3 estimates the unknown time-varying environmental disturbance online, obtains the disturbance estimate and uses it as a feedback signal in the outer loop control link, including:

[0029] Based on the dynamic model of underactuated underwater unmanned vehicle, auxiliary variables in the three motion directions of the vehicle, namely longitudinal, pitch and heading, are constructed. u ,e q ,e r ]for:

[0030]

[0031] Define the integral sliding mode surface of the underactuated underwater unmanned vehicle in the longitudinal, pitch and bow directions [s u ,s q ,s r ]for:

[0032]

[0033] Where a, b1, b2>0 are design parameters, x [y] =|x| y sign(x).

[0034] Based on the integral sliding surface of the longitudinal, pitch and heading of the underwater unmanned vehicle[s u ,s q ,s r ], a fast-converging disturbance observer is designed to perform online estimation of unknown time-varying environmental disturbances of the vehicle's longitudinal, pitch, and heading:

[0035]

[0036] Where, are the disturbance estimates of the underactuated underwater unmanned vehicle in the longitudinal u, pitch q and heading r directions, and a, k0, k1, k2>0, 0<α<1, β>1 are the design parameters.

[0037] Furthermore, the design of the robust backstepping fast feedback control law in step 4 to achieve accurate tracking of the reference trajectory by the underactuated underwater unmanned vehicle includes:

[0038] The robust fixed-time controller includes a kinematic controller and a dynamic controller, where the kinematic controller is used to stabilize the distance error variable ρ e (t) and the azimuth error variable [χ e (t),γ e (t)], the dynamic controller is used to stabilize the speed error variable [u e ,q e ,r e ].

[0039] Based on the tracking error dynamics model of underwater unmanned vehicle, the kinematic controller of the vehicle in the longitudinal, pitch and heading directions is designed. c ,q c ,r c ]for:

[0040]

[0041] Introducing a first-order nonlinear filter to improve the kinematic controller [u c ,q c ,r c ] to process:

[0042]

[0043] Where [T1, T2, T3] is the filter time constant; [u d ,q d ,r d ] is the filter control input.

[0044] Based on the filtered control input [u d ,q d ,r d ], defines the velocity tracking error of the vehicle in the longitudinal, pitch and heading directions [u e ,q e ,r e ]for:

[0045]

[0046] The longitudinal, pitch and bow dynamic controllers of the underactuated underwater unmanned vehicle are designed as follows:

[0047]

[0048] Where a i ,b i >0(i=u,q,r) is the design parameter.

[0049] Another object of the present invention is to provide an underwater unmanned vehicle robust and fast tracking control system using the underwater unmanned vehicle robust and fast tracking control method. The underwater unmanned vehicle robust and fast tracking control system includes:

[0050] Model building module, used to analyze the environmental interference effects of waves and currents, and to establish nonlinear kinematic and dynamic models of underactuated underwater unmanned vehicles, as well as tracking error dynamic models;

[0051] The disturbance estimation module is used to design a sliding mode disturbance observer to estimate the unknown time-varying environmental disturbance online, obtain the disturbance estimate value and use it as a feedback signal to act on the outer loop control link;

[0052] The tracking control module is used to design a robust nonlinear fast feedback control law to achieve reference trajectory tracking of underactuated underwater unmanned vehicles.

[0053] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the robust and rapid tracking control method for an underwater unmanned vehicle.

[0054] Another object of the present invention is to provide a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the steps of the robust and rapid tracking control method for an underwater unmanned vehicle.

[0055] Another object of the present invention is to provide an information data processing terminal, which is used to implement the robust and rapid tracking control system of the underwater unmanned vehicle.

[0056] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0057] First, the robust, fast-tracking control method based on a sliding mode observer proposed by this invention for underactuated underwater vehicles (UUVs) addresses the impact of environmental disturbances during navigation and enhances system robustness. The fast-converging observer and controller designed in this invention improve the convergence rate of error variables in the UUV system and enhance the time response capability of the control system.

[0058] Second, the underwater unmanned vehicle trajectory tracking method of the present invention ensures the fixed-time convergence characteristics of the under-actuated underwater unmanned vehicle system, effectively overcoming the limitations of traditional methods and finite-time methods, namely, over-reliance on the size of the system's initial state, and ultimately achieving accurate and rapid tracking of the underwater unmanned vehicle reference trajectory. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0060] Figure 1 This is a flow chart of a robust and fast tracking control method for an underwater unmanned vehicle provided by an embodiment of the present invention;

[0061] Figure 2 This is a schematic diagram of the spatial trajectory tracking control principle of an underwater unmanned vehicle provided by an embodiment of the present invention;

[0062] Figure 3 This is a schematic diagram of the spatial trajectory tracking of an underwater unmanned vehicle provided by an embodiment of the present invention;

[0063] Figure 4A Comparison of the spatial trajectory tracking performance of underwater unmanned vehicles provided by the embodiment of the present invention Figure 1 ;

[0064] Figure 4B Comparison of the spatial trajectory tracking performance of underwater unmanned vehicles provided by the embodiment of the present invention Figure 2 ;

[0065] Figure 4C Comparison of the spatial trajectory tracking performance of underwater unmanned vehicles provided by the embodiment of the present invention Figure 3 ;

[0066] Figure 4D FIG4 is a comparison of the spatial trajectory tracking performance of underwater unmanned vehicles provided by an embodiment of the present invention;

[0067] Figure 5AThe distance and azimuth error variable curve of the underwater unmanned vehicle without environmental interference provided by the embodiment of the present invention is Figure 1 ;

[0068] Figure 5B The distance and azimuth error variable curve of the underwater unmanned vehicle without environmental interference provided by the embodiment of the present invention is Figure 2 ;

[0069] Figure 5C The distance and azimuth error variable curve of the underwater unmanned vehicle without environmental interference provided by the embodiment of the present invention is Figure 3 ;

[0070] Figure 6A The variable curve of the distance and azimuth error of the underwater unmanned vehicle under environmental interference provided by the embodiment of the present invention is Figure 1 ;

[0071] Figure 6B The variable curve of the distance and azimuth error of the underwater unmanned vehicle under environmental interference provided by the embodiment of the present invention is Figure 2 ;

[0072] Figure 6C The variable curve of the distance and azimuth error of the underwater unmanned vehicle under environmental interference provided by the embodiment of the present invention is Figure 3 ;

[0073] Figure 7A The actual value and estimated value curve of the environmental interference to the underwater unmanned vehicle provided by the embodiment of the present invention are Figure 1 ;

[0074] Figure 7B The actual value and estimated value curve of the environmental interference to the underwater unmanned vehicle provided by the embodiment of the present invention are Figure 2 ;

[0075] Figure 7C The actual value and estimated value curve of the environmental interference to the underwater unmanned vehicle provided by the embodiment of the present invention are Figure 3 ;

[0076] Figure 8A This is a schematic diagram of the spatial trajectory tracking performance of an underwater unmanned vehicle under different initial conditions provided by an embodiment of the present invention. Figure 1 ;

[0077] Figure 8B This is a schematic diagram of the spatial trajectory tracking performance of an underwater unmanned vehicle under different initial conditions provided by an embodiment of the present invention. Figure 2 ;

[0078] Figure 8C This is a schematic diagram of the spatial trajectory tracking performance of an underwater unmanned vehicle under different initial conditions provided by an embodiment of the present invention. Figure 3 ;

[0079] Figure 8D 4 is a schematic diagram of the spatial trajectory tracking performance of an underwater unmanned vehicle under different initial conditions provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0080] 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.

[0081] In view of the problems existing in the prior art, the present invention provides a robust and fast tracking control method and system for an underwater unmanned vehicle. The present invention is described in detail below with reference to the accompanying drawings.

[0082] 1. Explanatory Examples In order to enable those skilled in the art to fully understand how to implement the present invention, this section provides an illustrative example that expands upon the technical solutions of the claims.

[0083] like Figure 1 As shown, the robust and fast tracking control method for an underwater unmanned vehicle provided by an embodiment of the present invention includes the following steps:

[0084] S101, constructing a nonlinear kinematic model, a dynamic model, and a tracking error dynamic model for an underactuated underwater unmanned vehicle;

[0085] S102, designing a sliding mode disturbance observer based on the nonlinear dynamic model of the underactuated underwater unmanned vehicle to perform online estimation of environmental disturbances to obtain a disturbance estimation value;

[0086] S103, designing a robust nonlinear fast feedback control law for an underactuated underwater unmanned vehicle to achieve robust, fast, and precise tracking control of the underwater unmanned vehicle.

[0087] As a preferred embodiment, Figure 2 As shown, the robust and fast tracking control method for an underwater unmanned vehicle provided by an embodiment of the present invention specifically includes the following steps:

[0088] (1) Considering the influence of environmental interference such as waves and currents, a nonlinear kinematic and dynamic model of the underactuated underwater unmanned vehicle is established;

[0089] (2) Establish the tracking error dynamics of underwater unmanned vehicles through error coordinate transformation;

[0090] (3) Design a sliding mode disturbance observer to estimate the unknown time-varying environmental disturbance online, obtain the disturbance estimate, and use it as a feedback signal in the outer loop control link to offset the impact of environmental disturbance on the underwater unmanned vehicle;

[0091] (4) Design a robust backstepping fast feedback control law to enable the underactuated underwater unmanned vehicle to accurately and quickly track the reference trajectory.

[0092] In step (1), considering the influence of environmental interference such as waves and currents, the following nonlinear kinematic and dynamic models of the underactuated underwater unmanned vehicle are established:

[0093] Kinematic model:

[0094]

[0095] Kinetic model:

[0096]

[0097] Where [x, y, z] and [θ, ψ] represent the position and orientation of the underwater unmanned vehicle, [u, v, w] and [q, r] represent the linear velocity and angular velocity of the underwater unmanned vehicle, respectively. u ,τ q ,τ r ] is the control input of the underwater unmanned vehicle longitudinal (u), pitch (q), and heading (r), τ di (i=1,2,3,5,6) represents unknown time-varying environmental interference, m ii represents the mass and inertia parameters of the underwater unmanned vehicle, d ii represents the damping term.

[0098] Since the ocean environment is constantly changing and the energy provided by the wave and current environment is limited, the interference τ di The change of the interference is limited, that is, for a certain unknown positive constant δ i , we have: |τ di |≤δ i .

[0099] In step (2), the position error in the earth coordinate system is converted to the hull coordinate system, that is:

[0100]

[0101] In the formula, [x d ,y d ,z d ] represents the smooth reference trajectory, J(η) represents the rotation matrix, which is defined as:

[0102]

[0103] like Figure 3 As shown, the distance error variable ρ between the underwater unmanned vehicle and the reference trajectory point is constructed e(t) and the azimuth error variable [χ e (t),γ e (t)] is:

[0104]

[0105] Taking the derivative of formula (3), we can get:

[0106]

[0107] Where,

[0108] Taking the derivative of Equation (5), we can obtain the tracking error dynamics of the underactuated underwater unmanned vehicle:

[0109]

[0110] In step (3), based on the underactuated underwater unmanned vehicle dynamics model, the auxiliary variables [e u ,e q ,e r ]:

[0111]

[0112] Then, define the integral sliding mode surfaces of the vehicle in the longitudinal, pitch, and bow directions:

[0113]

[0114] Where a, b1, b2>0 are design parameters, x [y] =|x| y sign(x).

[0115] Based on the above-defined integral sliding surface [s u ,s q ,s r ], the following fixed-time disturbance observer is designed to estimate the unknown time-varying environmental disturbances in the longitudinal, pitch, and bow directions of the vehicle:

[0116]

[0117] Where a, k0, k1, k2>0 are design parameters.

[0118] In step (4), the designed robust backstepping fast control law consists of two parts: a kinematic controller and a dynamic controller. The kinematic controller is used to stabilize the distance error variable ρ. e (t) and the azimuth error variable [χ e (t),γ e(t)], the dynamic controller is used to stabilize the speed error variable [u e ,q e ,r e ].

[0119] Based on the tracking error dynamics derived in step (2) (Eq. (7)), the longitudinal, pitch, and bow kinematic controllers of the vehicle are designed [u c ,q c ,r c ]for:

[0120]

[0121] Considering that the traditional backstepping control method needs to calculate the differential term To solve the computational explosion problem caused by this, the following first-order nonlinear filter is introduced to the kinematic controller [u c ,q c ,r c ] to process:

[0122]

[0123] Where [T1, T2, T3] is the filter time constant. c ,q c ,r c ]Through the first-order nonlinear filter, the filtered control input [u d ,q d ,r d ], and the differential term It can be directly calculated by formula (12) and can be used to replace the differential term required in the traditional backstepping control method Therefore, the computational explosion problem inherent in traditional backstepping control methods is avoided. Furthermore, the introduced first-order nonlinear filter ensures the fixed-time stability of the entire closed-loop system.

[0124] Based on the above derived filter control input [u d ,q d ,r d ], the velocity tracking errors of the vehicle in longitudinal, pitch and bow directions are defined as:

[0125]

[0126] The longitudinal, pitch, and bow-up dynamic controllers of the underactuated underwater unmanned vehicle can be designed as follows:

[0127]

[0128] Where a i ,b i>0(i=u,q,r) is the design parameter.

[0129] The robust and fast tracking control system for underwater unmanned vehicles provided by an embodiment of the present invention includes:

[0130] Model building module, used to analyze the environmental interference effects of waves and currents, and to establish nonlinear kinematic and dynamic models of underactuated underwater unmanned vehicles, as well as tracking error dynamic models;

[0131] The disturbance estimation module is used to design a sliding mode disturbance observer to estimate the unknown time-varying environmental disturbance online, obtain the disturbance estimate value and use it as a feedback signal to act on the outer loop control link;

[0132] The trajectory tracking module is used to design a robust backstepping fast feedback control law to achieve fast and accurate tracking of the reference trajectory of an underactuated underwater unmanned vehicle.

[0133] 2. Evidence of the Effects of the Embodiments The embodiments of the present invention have achieved some positive effects during the development or use process, and indeed have great advantages over the prior art. The following content describes them with reference to data, charts, etc. during the test process.

[0134] Simulation experiment verification and analysis: In order to verify the performance of the robust fast tracking control method for underactuated underwater unmanned vehicle designed in the embodiment of the present invention, a simulation model was established using Matlab, and the simulation time was set to 300s. The parameters of the underactuated underwater unmanned vehicle model are: m 11 =25kg,m 22 =17.5kg,m 33 =30kg,

[0135] m 55 =22.5kg m 2 ,m 66 =15kg m 2 ,d 11 =30kg s -1 ,d 22 =30kg s -1 ,d 33 =30kg s -1 ,d 55 =20kg m 2 s -1 ,d 66 =20kg m 2 s -1 ,Bh=5. The controller and observer parameters are set as: α=0.8,β=1.5,a=5,b1=b2=2,

[0136] k0=1.5,k1=k2=2,a ρ =bρ =0.02,a χ =b χ =a γ =b γ =0.2,a u =b u =a q =b q =a r =b r =2. The environmental interference is set to:

[0137]

[0138] In order to verify the effectiveness and superiority of the algorithm of the present invention, the following three comparative simulation scenarios are designed:

[0139] (1) In order to verify the time response capability of the control method designed by the present invention, the method (C1) proposed by the present invention is compared with the finite time backstepping control method (C2) and the traditional backstepping method (C3) without considering the influence of environmental interference. The simulation results are as follows: Figures 4A to 4D and Figures 5A to 5C shown.

[0140] (2) In order to verify the robustness of the designed control method, considering the influence of environmental disturbance, the sliding mode disturbance observer method (C1) proposed in this invention is compared with the finite time backstepping control method (C2) and the traditional backstepping method (C3). The simulation results are as follows: Figures 6A to 6C 、 Figures 7A to 7C shown.

[0141] (3) In order to verify the fixed time convergence characteristic of the algorithm designed in the embodiment of the present invention, that is, the convergence time of the system state error is independent of the initial state of the system, four groups of different initial states are set for the underactuated underwater unmanned vehicle to track the trajectory. The simulation results are as follows: Figures 8A to 8D shown.

[0142] Figures 4A to 4D is the comparison curve of the space trajectory tracking control performance of underactuated underwater unmanned vehicle, Figures 5A to 5C The variable curves of the distance and azimuth error of the underactuated underwater unmanned vehicle without environmental interference are shown in Figure 2. Figures 4A to 4D and Figures 5A to 5C It can be seen that without considering the influence of environmental interference, the three control methods can drive the underwater unmanned vehicle to accurately track the reference trajectory, and the distance and azimuth errors [ρ e (t),χ e (t),γ e(t)] converge to the vicinity of zero. Furthermore, it can be observed that the fast tracking control method designed in the present invention has a faster error convergence rate than the finite-time backstepping control method and the traditional backstepping method. Therefore, the control method designed in the present invention can effectively improve the time response capability of the control system of the underactuated underwater unmanned vehicle.

[0143] Figures 6A to 6C The actual and estimated value curves of the environmental interference to the underwater unmanned vehicle are: Figures 7A to 7C The variable curves of the distance and azimuth errors of underwater unmanned vehicles under environmental interference. Figures 6A to 6C It is demonstrated that the sliding mode disturbance observer designed in the present invention can quickly and accurately estimate environmental disturbances. Figures 7A to 7C It shows that under the influence of environmental interference, the fast tracking control method based on the sliding mode disturbance observer designed in this invention can still drive the underwater unmanned vehicle to quickly and accurately track the reference trajectory, and ensure the distance and azimuth errors [ρ e (t),χ e (t),γ e (t)] is stable in the vicinity of zero. However, under the finite-time backstepping control method and the traditional backstepping method, the range and azimuth errors of the underwater unmanned vehicle vary significantly. Therefore, the control method designed in this invention can enhance the robustness of trajectory tracking of the underactuated unmanned vehicle.

[0144] Figures 8A to 8D The spatial trajectory tracking performance of underactuated underwater unmanned vehicle under different initial conditions. Figures 8A to 8D It can be seen that even under different initial position conditions, the control method designed by the present invention can make the actual trajectory of the underactuated underwater unmanned vehicle converge to the reference trajectory simultaneously. Furthermore, it is confirmed that the control method designed by the present invention has fixed-time convergence stability, that is, it is independent of the initial state of the system.

[0145] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic; the software portion can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those skilled in the art will appreciate that the above-mentioned devices and methods can be implemented using computer-executable instructions and / or contained in processor control code, for example, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0146] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A robust and fast tracking control method for an underwater unmanned vehicle, characterized in that: The robust fast tracking control method for underwater unmanned vehicles includes: constructing a nonlinear kinematic model, a dynamic model and a tracking error dynamic model of the under-actuated underwater unmanned vehicle; designing a sliding mode disturbance observer based on the nonlinear dynamic model of the under-actuated underwater unmanned vehicle and performing disturbance estimation; designing a robust nonlinear fast feedback control law for the under-actuated underwater unmanned vehicle to achieve fast and accurate trajectory tracking of the under-actuated underwater unmanned vehicle.

2. The robust and fast tracking control method for an underwater unmanned vehicle according to claim 1, wherein: The robust fast tracking control method for underwater unmanned vehicles includes the following steps: Step 1: Analyze the environmental interference effects of waves and currents and establish a nonlinear kinematic and dynamic model of the underactuated underwater unmanned vehicle; Step 2: Based on the error coordinate transformation, the underwater unmanned vehicle tracking error dynamics model is established; Step 3: Design a sliding mode disturbance observer to estimate the unknown time-varying environmental disturbance online, obtain the disturbance estimate, and use the disturbance estimate as a feedback signal in the outer loop control link; Step 4: Design a robust nonlinear fast feedback control law to enable the underactuated underwater unmanned vehicle to accurately track the reference trajectory.

3. The robust and fast tracking control method for an underwater unmanned vehicle according to claim 2, wherein: The nonlinear kinematic model of the underactuated underwater unmanned vehicle in step 1 is: The dynamic model of the underactuated underwater unmanned vehicle is: Where [x, y, z] and [θ, ψ] represent the position and orientation of the underwater unmanned vehicle, [u, v, w] and [q, r] represent the linear velocity and angular velocity of the underwater unmanned vehicle, respectively. u ,τ q ,τ r ] is the control input of the underwater unmanned vehicle longitudinal u, pitch q and heading r, τ di (i=1,2,3,5,6) represents unknown time-varying environmental interference, m ii represents the mass and inertia parameters of the underwater unmanned vehicle, d ii represents the damping term; for the unknown positive constant δ i , there exists |τ di |≤δ i .

4. The robust and fast tracking control method for an underwater unmanned vehicle according to claim 2, wherein: The second step of establishing the underwater unmanned vehicle tracking error dynamics model based on error coordinate transformation includes: Convert the position error in the earth coordinate system to the hull coordinate system: In the formula, [x d ,y d ,z d ] represents the smooth reference trajectory, J(η) represents the rotation matrix, which is defined as: Construct the distance error variable ρ between the underwater unmanned vehicle and the reference trajectory point e (t) and the azimuth error variable [χ e (t),γ e (t)] is: Derivative the position error expression in the hull coordinate system, we get: Where, By differentiating the distance error variable and orientation error variable expressions between the underwater unmanned vehicle and the reference trajectory point, the tracking error dynamic model of the underactuated underwater unmanned vehicle is obtained as follows:

5. The robust and fast tracking control method for an underwater unmanned vehicle according to claim 2, wherein: The design of the sliding mode disturbance observer in step 3 estimates the unknown time-varying environmental disturbance online, obtains the disturbance estimate and uses it as a feedback signal in the outer loop control link, including: Based on the dynamic model of underactuated underwater unmanned vehicle, auxiliary variables in the three motion directions of the vehicle, namely longitudinal, pitch and heading, are constructed. u ,e q ,e r ]for: Define the integral sliding mode surface of the underactuated underwater unmanned vehicle in the longitudinal, pitch and bow directions [s u ,s q ,s r ]for: Where a, b1, b2>0 are design parameters, x [y] =|x| y sign(x); Based on the integral sliding surface of the longitudinal, pitch and heading of the underwater unmanned vehicle[s u ,s q ,s r ], a sliding mode disturbance observer is designed to perform online estimation of the unknown time-varying environmental disturbances of the longitudinal, pitch and heading of the vehicle: Where, are the disturbance estimates of the underactuated underwater unmanned vehicle in the longitudinal u, pitch q and heading r directions, and a, k0, k1, k2>0, 0<α<1, β>1 are the design parameters.

6. The robust and fast tracking control method for an underwater unmanned vehicle according to claim 2, wherein: The design of the robust nonlinear fast feedback control law in step 4 to achieve accurate and rapid tracking of the reference trajectory by the underactuated underwater unmanned vehicle includes: The robust nonlinear fast control law includes a kinematic controller and a dynamic controller, where the kinematic controller is used to stabilize the distance error variable ρ e (t) and the azimuth error variable [χ e (t),γ e (t)], the dynamic controller is used to stabilize the speed error variable [u e ,q e ,r e ]; Based on the tracking error dynamics model of underwater unmanned vehicle, the kinematic controller of the vehicle in the longitudinal, pitch and heading directions is designed. c ,q c ,r c ]for: Introducing a first-order nonlinear filter to improve the kinematic controller [u c ,q c ,r c ] to process: Where [T1, T2, T3] is the filter time constant; [u d ,q d ,r d ] is the filter control input; Based on the filtered control input [u d ,q d ,r d ], defines the velocity tracking error of the vehicle in the longitudinal, pitch and heading directions [u e ,q e ,r e ]for: The longitudinal, pitch and bow dynamic controllers of the underactuated underwater unmanned vehicle are designed as follows: Where a i ,b i >0(i=u,q,r) is the design parameter.

7. A robust and fast tracking control system for an underwater unmanned vehicle using the robust and fast tracking control method for an underwater unmanned vehicle according to any one of claims 1 to 6, characterized in that: The robust and fast tracking control system for underwater unmanned vehicles includes: Model building module, used to analyze the environmental interference effects of waves and currents, and to establish nonlinear kinematic and dynamic models of underactuated underwater unmanned vehicles, as well as tracking error dynamic models; The disturbance estimation module is used to design a sliding mode disturbance observer to estimate the unknown time-varying environmental disturbance online, obtain the disturbance estimate value and use it as a feedback signal to act on the outer loop control link; The trajectory tracking module is used to design robust nonlinear fast feedback control laws to achieve fast and accurate trajectory tracking of underactuated underwater unmanned vehicles.

8. A computer device, characterized in that: The computer device includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor executes the steps of the robust and fast tracking control method for an underwater unmanned vehicle according to any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the robust and fast tracking control method for an underwater unmanned vehicle according to any one of claims 1 to 6.

10. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the robust and rapid tracking control system for underwater unmanned vehicles as described in claim 7.

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