Fault-tolerant control method and control system of unmanned boat based on path planning

Abstract

The present invention discloses a fault-tolerant control method and control system for an unmanned boat based on path planning, which comprises: judging whether the unmanned boat has a fault, the fault being that the unmanned boat is restricted to a positive interval or a negative interval; if so, planning a target trajectory set including a plurality of alternating forward semicircular trajectories and turning semicircular trajectories from the fault starting position to the target position, the radius of the forward semicircular trajectory being greater than the radius of the turning semicircular trajectory, taking the trajectory switching position of the forward semicircular trajectory and the turning semicircular trajectory as the target point and the forward semicircular trajectory and the turning semicircular trajectory being tangent at the target point, and all target points being located on a straight line from the fault starting position to the target position; controlling the unmanned boat to track the target trajectory set, and when the unmanned boat reaches the target point, tracking the next semicircular trajectory as a new target trajectory until the tracking of all target trajectories in the target trajectory set is completed. By means of the above method, it is achieved that the unmanned boat can continue to sail to the target position when a fault occurs.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned boat control, and more specifically, relates to an unmanned boat fault-tolerant control method based on path planning and a control system thereof. Background Art

[0002] In recent decades, unmanned boats have made great progress and are an indispensable tool for marine engineering. Due to their high efficiency, flexibility and low operating cost, unmanned boats have been widely used in water quality monitoring, marine surveys, military reconnaissance and other fields. In some water missions, the workload of unmanned boats (including sensors, actuators, energy systems) is usually expensive. In addition, the movement of unmanned boats is often disturbed by the marine environment such as wind, waves, tides, surges and underwater obstacles (coral reefs, mud), which can easily lead to failure of the unmanned boat actuators. There is a situation where the actuator cannot be zeroed, which means that the control input is always limited to the positive interval or the negative interval. For example, if one side of the catamaran loses power and the steering servo of the monohull is stuck, the propulsion can only go left or right, so the unmanned boat cannot sail in a straight line, but can only run to the left or right front. In this case, it is very difficult to complete the navigation trajectory tracking task, and the possibility of returning to the port safely is extremely low.

[0003] Therefore, it is of great significance to design a fault-tolerant control method for unmanned boats with monotonic constraints on heading angles. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides an unmanned boat fault-tolerant control method and a control system based on path planning, which aims to solve the fault-tolerant control problem of an unmanned boat with a monotonic heading constraint fault.

[0005] To achieve the above object, according to one aspect of the present invention, a fault-tolerant control method for an unmanned boat based on path planning is provided, comprising:

[0006] Step S1: Determine whether the unmanned boat has a fault, where the unmanned boat cannot move in a straight line, can only turn to one side, and can only move forward but not backward. If so, execute step S2; if not, repeat step S1;

[0007] Step S2: According to the dynamic model of the unmanned boat and the fault information, a target trajectory set from the fault start position to the target position is planned, wherein the target trajectory set includes a plurality of alternating forward semicircular trajectories and turning semicircular trajectories, wherein the radius of the forward semicircular trajectory is greater than the radius of the turning semicircular trajectory, and the trajectory switching position of the forward semicircular trajectory and the turning semicircular trajectory is taken as the target point, and the forward semicircular trajectory and the turning semicircular trajectory are tangent to each other at the target point, and all the target points are located on a straight line from the fault start position to the target position;

[0008] Step S3: Control the unmanned boat to track the target trajectory set. When the unmanned boat reaches the target point, the next semicircle trajectory is tracked as a new target trajectory until all target trajectories in the target trajectory set are tracked.

[0009] In one embodiment, the dynamic model of the unmanned boat is:

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

[0016] Among them, (x, y) represents the position coordinates of the unmanned boat, ψ represents the heading of the unmanned boat, w, v, r represent the longitudinal velocity, sway velocity and angular velocity respectively, τ u , τ r represent the propeller power and the steering angle respectively, d 1 ,d 2 ,d 3 are the hydrodynamic damping coefficients for surge, sway and bow roll, m 1 ,m 2 ,m 3 They are the inertial masses of the additional mass effects of the unmanned boat in the lateral, longitudinal and heading directions respectively.

[0017] In one embodiment, the fault information of the unmanned boat is represented as:

[0018]

[0019] are respectively the propeller power and steering angle when tracking the target trajectory, where 0≤τ u ≤τ umax , τ umax is the maximum power that the thruster can achieve, when 0<τ rmin ≤τ r ≤τ rmax , indicating that the unmanned boat can only turn right, (τ rmin ,τ rmax ) is the turning angle range for turning right, when τ' rmin ≤τ r ≤τ' rmax<0, indicating that the unmanned boat can only turn left, (τ' rmin ,τ' rmax ) is the steering angle range for turning left.

[0020] In one embodiment, each target trajectory starts from the previous target point and ends at the next target point. When the unmanned boat is located at the starting point of the target trajectory, the end point of the current target trajectory is set within the reachable area of ​​the unmanned boat. r (η 0 ,η t ), η 0 =(x 0 ,y 0 ,ψ 0 ) is the target trajectory S r The starting point coordinates and heading, η t =(x t ,y t ,ψ t ) is the target trajectory S r The end point coordinates and heading, when the unmanned boat is at the starting point η 0 When , the corresponding end point satisfies the following conditions:

[0021]

[0022]

[0023] in is η in the reachable area t From η 0 The farthest position, is the predetermined upper bound of the longitudinal velocity, is the predetermined upper limit of the sway velocity, r is a predetermined lower bound on the angular velocity.

[0024] In one embodiment, for any target trajectory S r (η 0 ,η t ), η 0 = (x 0 ,y 0 ,ψ 0 ) is each target trajectory S r The starting point, η t =(x t ,y t ,ψ t ) is each target trajectory S r The end point of each target trajectory S r (η 0 ,η t )satisfy:

[0025]

[0026]

[0027] ψ r =ψ 0 +r r t

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034] Among them, (x r ,y r ,ψ r ) is the target trajectory S r The target value of any point on The target trajectory S r The trajectory radius, w r 、v r 、r r They are respectively the unmanned boat on the target trajectory S r The target values ​​of longitudinal velocity, sway velocity and angular velocity on r is the predetermined lower bound of the angular velocity, is the predetermined upper bound of the angular velocity.

[0035] In one embodiment, the target trajectory set includes n r target points, target point set Among them, η ri represents the i-th target point, and the target point set satisfies:

[0036] P ri =(x ri ,y ri )

[0037]

[0038]

[0039]

[0040]

[0041] Among them, (x ri ,y ri ) represents the coordinates of the i-th target point, (x m ,y m ) indicates the fault starting position, (x f ,y f ) represents the target position, d rf is the diameter of the forward semicircular trajectory, d rt is the diameter of the turning semicircular trajectory, d rf >d rt , ψ ri is the heading of the unmanned boat at the i-th target point, w r 、v r They are the target trajectory S of the unmanned boat with the i-th target point as the end point. r Target values ​​of longitudinal velocity and sway velocity on the vehicle;

[0042] and

[0043]

[0044] Among them, floor(.) is the rounding down function.

[0045] In one embodiment, the target trajectory set includes n r +1 target track, target track set And S ri =S r (η r(i-1) ,η ri ), indicating that the starting point of the i-th target trajectory is η r(i-1) The end point is η ri , Indicates that the starting point of the last target trajectory is The end point is the target location.

[0046] In one embodiment, step S3 includes, according to the dynamic error system of the unmanned boat, using the trajectory tracking control law of the unmanned boat to control the unmanned boat to track the target trajectory set, wherein:

[0047] The dynamic error system of the unmanned boat is expressed as ξ e =[x e ,y e ,ψ e ,w e ,v e ,r e ],satisfy:

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] Among them, x e =x r -x,y e =y r -y,ψ e =ψ r -ψ,w e =w r -w,v e =v r -v, r e =r r -r;

[0055]

[0056] The trajectory tracking control law of the unmanned boat is:

[0057]

[0058]

[0059] Among them, a 1 、a 2 、a 3 、a 4 、a 5 、a 6 is the control parameter of the control law and satisfies

[0060] a 1 >d 2 -d 1

[0061]

[0062]

[0063] a 4 >0

[0064] a 5 >-d 3

[0065] a 6>0

[0066] In one embodiment, in step S3, the fault-tolerant control step of the unmanned boat includes:

[0067] Step S31: Determine the current target trajectory;

[0068] Step S32: Control the unmanned boat to track the current target trajectory, and calculate the distance between the current position of the unmanned boat and the end point of the target trajectory during the tracking period, and determine whether the distance is less than a preset error value. If not, it means that the tracking of the current target trajectory is not completed, and step S32 is repeated; if yes, it means that the tracking of the current target trajectory is completed, and step S33 is executed;

[0069] Step S33: Determine whether all target trajectories in the target trajectory set have been tracked. If not, take the next target trajectory as the current target trajectory to be tracked and jump to step S32. If yes, it means that the target position has been reached and the tracking is ended.

[0070] According to another aspect of the present invention, there is provided an unmanned boat fault-tolerant control system based on path planning, comprising:

[0071] A fault identification unit is used to determine whether the unmanned boat has a fault, wherein the unmanned boat cannot move in a straight line, can only turn to one side, and can only move forward but not backward;

[0072] A trajectory planning unit is used to plan a target trajectory set from a fault start position to a target position according to a dynamic model of the unmanned boat and fault information, wherein the target trajectory set includes a plurality of alternating forward semicircular trajectories and turning semicircular trajectories, wherein the radius of the forward semicircular trajectory is greater than the radius of the turning semicircular trajectory, and the trajectory switching position of the forward semicircular trajectory and the turning semicircular trajectory is used as a target point, and the forward semicircular trajectory and the turning semicircular trajectory are tangent to each other at the target point, and all target points are located on a straight line from the fault start position to the target position;

[0073] The trajectory tracking unit is used to control the unmanned boat to track the target trajectory set. When the unmanned boat reaches the target point, the next semicircle trajectory is tracked as a new target trajectory until the tracking of all target trajectories in the target trajectory set is completed.

[0074] The present application proposes a corresponding fault-tolerant control method for the fault that the control input of an unmanned boat is always restricted to a positive interval or a negative interval. By planning alternating forward semicircular trajectories and turning semicircular trajectories, a target trajectory set from a starting position to a target position is formed, and the unmanned boat is controlled to switch and track the target trajectory set, thereby improving the flexibility and feasibility of the fault-tolerant control of the unmanned boat, and realizing the fault-tolerant control and trajectory tracking of the unmanned boat device in the scenario where one side of the catamaran loses power or the steering gear is stuck, the heading angle is fixed, and the unmanned boat cannot sail in a straight line but can only perform spiral motion. This provides a new idea for the fault-tolerant control and trajectory tracking of the unmanned boat in fault scenarios, improves the reliability of the unmanned boat in performing tasks, and opens up new prospects for the application of unmanned boats. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 A flowchart of the steps of a fault-tolerant control method for an unmanned boat based on path planning according to an embodiment;

[0076] Figure 2 A schematic diagram of a target trajectory set planned in one embodiment;

[0077] Figure 3 The diagram is a schematic diagram of the state decomposition of an unmanned boat during operation according to an embodiment. DETAILED DESCRIPTION

[0078] 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 accompanying drawings and 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. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0079] like Figure 1 The following is a flow chart of the steps of a fault-tolerant control method for an unmanned boat based on path planning in an embodiment. The control method includes:

[0080] Step S100: Determine whether the unmanned boat has a fault, where the unmanned boat cannot move in a straight line, can only turn to one side, and can only move forward but not backward.

[0081] When the unmanned boat fails, step S2 is executed; when the unmanned boat does not fail, step S100 is repeated.

[0082] Among them, the fault is that the unmanned boat cannot move in a straight line, can only turn to one side and can only move forward but not backward, that is, the control input of the unmanned boat is always limited to the positive range or the negative range.

[0083] Step S200: planning a target trajectory set from the fault start position to the target position according to the dynamic model of the unmanned boat and the fault information, wherein the target trajectory set includes a plurality of alternating forward semicircular trajectories and turning semicircular trajectories.

[0084] Among them, the radius of the forward semicircular trajectory is larger than the radius of the turning semicircular trajectory, the trajectory switching position of the forward semicircular trajectory and the turning semicircular trajectory is taken as the target point and the forward semicircular trajectory and the turning semicircular trajectory are tangent at the target point, and all target points are located on a straight line from the fault starting position to the target position.

[0085] like Figure 2 In the embodiment of the plan, the fault starting position η r0 =(x m ,y m ) to the target location The target trajectory set It includes n r +1 target track. Among them, S ri represents the i-th target trajectory, which can be expressed as S ri =S r (η r(i-1) ,η ri ), that is, the i-th target trajectory S ri For a target point η r(i-1) To the target point η ri The number of target trajectories is an odd number, wherein the odd-numbered target trajectories are forward semicircular trajectories (the end point of the trajectory is located on the side close to the target position), and the even-numbered target trajectories are turning semicircular trajectories (the end point of the trajectory is located on the side away from the target position), thus forming a forward semicircular trajectory-turning semicircular trajectory...-forward semicircular trajectory n r +1 alternating trajectory. All target points (including the fault start position and the target position) are located on a straight line. The forward semicircular trajectory and the steering semicircular trajectory are tangent at the target point.

[0086] In the fault-tolerant control of the unmanned boat, the target trajectory, trajectory generation rules and trajectory tracking control law that conform to the unmanned boat model are obtained based on the dynamics of the unmanned boat, such as Figure 3 , the three-degree-of-freedom dynamic model of the unmanned boat is considered in terms of the three degrees of freedom of longitudinal, transverse and bow pitch.

[0087] In one embodiment, the dynamic model of the unmanned boat is:

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094] Among them, (x, y) represents the position coordinates of the unmanned boat, ψ represents the heading of the unmanned boat, w, v, r represent the longitudinal velocity, sway velocity and angular velocity respectively, τ u , τ r represent the propeller power and the steering angle respectively, d 1 ,d 2 ,d 3 are the hydrodynamic damping coefficients for surge, sway and bow roll, m 1 ,m 2 ,m 3 They are the inertial masses of the additional mass effects of the unmanned boat in the lateral, longitudinal and heading directions respectively.

[0095] Specifically, k can be adjusted according to the actual situation. 1 ~k 7 Assignment. In a specific embodiment, the dynamic model of the unmanned boat after assignment is:

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] In one embodiment, the fault information of the unmanned boat is represented as:

[0103]

[0104] are respectively the propeller power and steering angle when tracking the target trajectory, where 0≤τ u ≤τ umax , τ umax is the maximum power that the thruster can achieve, when 0<τ rmin ≤τ r ≤τ rmax , indicating that the unmanned boat can only turn right, (τ rmin ,τrmax ) is the turning angle range for turning right, when τ' rmin ≤τ r ≤τ' rmax <0, indicating that the unmanned boat can only turn left, (τ' rmin ,τ' rmax ) is the steering angle range for turning left.

[0105] For example, the actuator fault saturation of the unmanned boat is:

[0106] 0≤τ u ≤4000,2≤τ r ≤20

[0107] It means that the propeller power of the unmanned boat is less than 4000, and the unmanned boat can only turn right with a turning angle of 2 to 20.

[0108] In one embodiment, for each target trajectory, the previous target point is taken as the starting point and the next target point is taken as the end point. When the unmanned boat is located at the starting point of the target trajectory, the end point of the current target trajectory is set within the reachable area of ​​the unmanned boat. Any target trajectory S is defined as r (η 0 ,η t ), η 0 = (x 0 ,y 0 ,ψ 0 ) is the target trajectory S r The starting point coordinates and heading, η t =(x t ,y t ,ψ t ) is the target trajectory S r The end point coordinates and heading, when the unmanned boat is at the starting point η 0 When , the corresponding end point satisfies the following conditions:

[0109]

[0110]

[0111] in is η in the reachable area t From η 0 The farthest position, is the predetermined upper bound of the longitudinal velocity, is the predetermined upper limit of the sway velocity, r is a predetermined lower bound on the angular velocity.

[0112] In one embodiment, for any target trajectory S r (η 0 ,η t ), η0 =(x 0 ,y 0 ,ψ 0 ) is each target trajectory S r The starting point, η t =(x t ,y t ,ψ t ) is each target trajectory S r The end point of each target trajectory S r (η 0 ,η t )satisfy:

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122] Among them, (x r ,y r ,ψ r ) is the target trajectory S r The target value of any point on The target trajectory S r The trajectory radius, w r 、v r 、r r They are respectively the unmanned boat on the target trajectory S r The target values ​​of longitudinal velocity, sway velocity and angular velocity on r is the predetermined lower bound of the angular velocity, is the predetermined upper bound of the angular velocity.

[0123] In one embodiment, according to the fault starting position n r0 =(x m ,y m ) to the target location Plan a series of target points The target point set satisfies:

[0124] P ri =(x ri ,y ri )

[0125]

[0126]

[0127]

[0128]

[0129] Among them, (x ri ,y ri ) represents the coordinates of the i-th target point, (x m ,y m ) indicates the fault starting position, (x f ,y f ) represents the target position, d rf is the diameter of the forward semicircular trajectory, d rt is the diameter of the turning semicircular trajectory, d rf >d rt , ψ ri is the heading of the unmanned boat at the i-th target point, w r 、v r They are the target trajectory S of the unmanned boat with the i-th target point as the end point. r Target values ​​of longitudinal velocity and sway velocity.

[0130] in,

[0131]

[0132] Among them, floor(.) is the rounding down function.

[0133] Based on the above planned target points, a plan is made including n r +1 target track set and Indicates that the starting point of the i-th target trajectory is η r(i-1) The end point is η ri , Indicates that the starting point of the last target trajectory is The end point is the target location.

[0134] After planning the target trajectory set, execute

[0135] Step S300: Control the unmanned boat to track the target trajectory set. When the unmanned boat reaches the target point, the next semicircle trajectory is tracked as a new target trajectory until all target trajectories in the target trajectory set are tracked.

[0136] Specifically, the target trajectory set includes n r +1 target track, the unmanned boat tracks the target tracks in turn, and when the unmanned boat reaches the target point, the next half circle track is tracked as the new target track.

[0137] Specifically, according to the dynamic error system of the unmanned boat, the trajectory tracking control law of the unmanned boat is used to control the unmanned boat to track the target trajectory set.

[0138] Among them, the dynamic error system of the unmanned boat is expressed as ξ e =[x e ,y e ,ψ e ,w e ,v e ,r e ],satisfy:

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145] Among them, x e =x r -x,y e =y r -y,ψ e =ψ r -ψ,w e =w r -w,v e =v r -v, r e =r r -r, Among them, the parameters with subscript r represent the target value of trajectory planning, while those without subscript r represent the actual state value of the unmanned boat.

[0146] In one embodiment, the trajectory tracking control law of the unmanned boat is:

[0147]

[0148]

[0149] Among them, a 1 、a 2 、a 3 、a 4 、a 5 、a 6 is the control parameter of the control law and satisfies

[0150] a 1 >d 2 -d 1

[0151]

[0152]

[0153] a 4 >0

[0154] a 5 >-d 3

[0155] a 6 >0

[0156] During the actual tracking, follow the steps below to track:

[0157] Step S310: Determine the current target trajectory;

[0158] Step S320: Control the unmanned boat to track the current target trajectory, and calculate the distance between the current position of the unmanned boat and the end point of the target trajectory during the tracking period, and determine whether the distance is less than a preset error value. If not, it means that the tracking of the current target trajectory is not completed, and step S320 is repeated; if so, it means that the tracking of the current target trajectory is completed, and step S330 is executed;

[0159] Step S330: Determine whether all target trajectories in the target trajectory set have been tracked. If not, take the next target trajectory as the current target trajectory to be tracked and jump to step S320. If yes, it means that the target position has been reached and the tracking is ended.

[0160] The code is as follows:

[0161] Step 1: Plan a series of target points And set the target point as the tangent point between the trajectories to plan the trajectory set

[0162] Step 2: For i=0:n r +1; (follow the target track in sequence)

[0163] Step 3: While true;

[0164] Step 4: Using controller τ u and τ r Control the unmanned boat to track the target trajectory S ri ;

[0165] Step 5: If||η-η ri ||<∈; (calculate the difference between the current state and the target point state)

[0166] Step 6: Break;

[0167] Step 7: End;

[0168] Step 8: End;

[0169] Step 9: End.

[0170] In order to reach the specified target, the trajectory tracking controller τ is used u and τ r Control the unmanned boat to track the target trajectory S r1 , and constantly judge the current state η and the first target point η r1 Norm of difference ||η-η r1 ||. When the error norm is less than a certain value, the target trajectory is switched to S r2 , and judge the norm of the difference between the current state and the second target point, so as to continuously switch the target trajectory and target point, such as Figure 2 Finally, the unmanned boat tracks several forward trajectories and steering trajectories through the designed trajectory tracking control law, reaches the target point, and completes the return mission, such as Figure 2 .

[0171] Accordingly, the present application also relates to an unmanned boat fault-tolerant control system, which comprises:

[0172] A fault identification unit is used to determine whether the unmanned boat has a fault, wherein the unmanned boat cannot move in a straight line, can only turn to one side, and can only move forward but not backward;

[0173] A trajectory planning unit is used to plan a target trajectory set from a fault start position to a target position according to a dynamic model of the unmanned boat and fault information, wherein the target trajectory set includes a plurality of alternating forward semicircular trajectories and turning semicircular trajectories, wherein the radius of the forward semicircular trajectory is greater than the radius of the turning semicircular trajectory, and the trajectory switching position of the forward semicircular trajectory and the turning semicircular trajectory is used as a target point, and the forward semicircular trajectory and the turning semicircular trajectory are tangent to each other at the target point, and all target points are located on a straight line from the fault start position to the target position;

[0174] The trajectory tracking unit is used to control the unmanned boat to track the target trajectory set. When the unmanned boat reaches the target point, the next semicircle trajectory is tracked as a new target trajectory until the tracking of all target trajectories in the target trajectory set is completed.

[0175] The unmanned boat fault-tolerant control system is used to implement the above control method. The specific details are introduced above and will not be repeated here.

[0176] The present application proposes a corresponding fault-tolerant control method for the fault that the control input of an unmanned boat is always restricted to a positive interval or a negative interval. By planning alternating forward semicircular trajectories and turning semicircular trajectories, a target trajectory set from a starting position to a target position is formed, and the unmanned boat is controlled to switch and track the target trajectory set, thereby improving the flexibility and feasibility of the fault-tolerant control of the unmanned boat, and realizing the fault-tolerant control and trajectory tracking of the unmanned boat device in the scenario where one side of the catamaran loses power or the steering gear is stuck, the heading angle is fixed, and the unmanned boat cannot sail in a straight line but can only perform spiral motion. This provides a new idea for the fault-tolerant control and trajectory tracking of the unmanned boat in fault scenarios, improves the reliability of the unmanned boat in performing tasks, and opens up new prospects for the application of unmanned boats.

[0177] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fault-tolerant control method for an unmanned boat based on path planning, characterized in that: include: Step S1: Determine whether the unmanned boat has a fault, where the unmanned boat cannot move in a straight line, can only turn to one side, and can only move forward but not backward. If so, execute step S2; if not, repeat step S1; Step S2: According to the dynamic model of the unmanned boat and the fault information, a target trajectory set from the fault start position to the target position is planned, wherein the target trajectory set includes a plurality of alternating forward semicircular trajectories and turning semicircular trajectories, wherein the radius of the forward semicircular trajectory is greater than the radius of the turning semicircular trajectory, and the trajectory switching position of the forward semicircular trajectory and the turning semicircular trajectory is taken as the target point, and the forward semicircular trajectory and the turning semicircular trajectory are tangent to each other at the target point, and all the target points are located on a straight line from the fault start position to the target position; Step S3: Control the unmanned boat to track the target trajectory set. When the unmanned boat reaches the target point, the next semicircle trajectory is tracked as a new target trajectory until all target trajectories in the target trajectory set are tracked. The dynamic model of the unmanned boat is: Among them, (x, y) represents the position coordinates of the unmanned boat, ψ represents the heading of the unmanned boat, w, v, r represent the longitudinal velocity, sway velocity and angular velocity respectively, τ u , τ r represent the propeller power and the steering angle respectively, d1, d2, d3 are the hydrodynamic damping coefficients during longitudinal surge, transverse sway and bow pitch, respectively; m1, m2, m3 are the inertial masses of the additional mass effects of the unmanned boat in the transverse, longitudinal and heading directions, respectively; The fault information of the unmanned boat is expressed as: are respectively the propeller power and steering angle when tracking the target trajectory, where 0≤τ u ≤τ umax , τ umax is the maximum power that the thruster can achieve, when 0<τ rmin ≤τ r ≤τ rmax , indicating that the unmanned boat can only turn right, (τ rmin ,τ rmax ) is the turning angle range for turning right, when τ' rmin ≤τ r ≤τ' rmax <0, indicating that the unmanned boat can only turn left, (τ' rmin ,τ' rmax ) is the steering angle range for turning left.

2. The fault-tolerant control method for an unmanned boat based on path planning as claimed in claim 1, characterized in that: Each target trajectory starts from the previous target point and ends at the next target point. When the unmanned boat is at the starting point of the target trajectory, the end point of the current target trajectory is set within the reachable area of ​​the unmanned boat. Define any target trajectory S r (η0,η t ), η0=(x0,y0,ψ0) is the target trajectory S r The starting point coordinates and heading, η t =(x t ,y t ,ψ t ) is the target trajectory S r The terminal coordinates and heading, when the unmanned boat is located at the starting point η0, the corresponding terminal satisfies the following conditions: in is the η in the reachable area t The farthest position from η0, is the predetermined upper bound of the longitudinal velocity, is the predetermined upper limit of the sway velocity, r is a predetermined lower bound on the angular velocity.

3. The fault-tolerant control method for an unmanned boat based on path planning as claimed in claim 1, characterized in that: For any target trajectory S r (η0,η t ), η0=(x0,y0,ψ0) is each target trajectory S r The starting point, η t =(x t ,y t ,ψ t ) is each target trajectory S r The end point of each target trajectory S r (η0,η t )satisfy: ψ r =ψ0+r r t Among them, (x r ,y r ,ψ r ) is the target trajectory S r The target value of any point on The target trajectory S r The trajectory radius, w r 、v r 、r r They are respectively the unmanned boat on the target trajectory S r The target values ​​of longitudinal velocity, sway velocity and angular velocity on the surface, t is the time from the starting point to the current position, r is the predetermined lower bound of the angular velocity, is the predetermined upper bound of the angular velocity.

4. The fault-tolerant control method for an unmanned boat based on path planning as claimed in claim 1, characterized in that: The target trajectory set includes n r target points, target point set Among them, η ri represents the i-th target point, and the target point set satisfies: P ri =(x ri ,y ri ) Among them, (x ri ,y ri ) represents the coordinates of the i-th target point, (x m ,y m ) indicates the fault starting position, (x f ,y f ) represents the target position, d rf is the diameter of the forward semicircular trajectory, d rt is the diameter of the turning semicircular trajectory, d rf >d rt , ψ ri is the heading of the unmanned boat at the i-th target point, w r 、v r are the target trajectory S of the unmanned boat with the i-th target point as the end point. r Target values ​​of longitudinal velocity and sway velocity on the vehicle; and Among them, floor(.) is the rounding down function.

5. The fault-tolerant control method for an unmanned boat based on path planning as claimed in claim 4, characterized in that: The target trajectory set includes n r +1 target track, target track set And S ri =S r (η r(i-1) ,η ri ), indicating that the starting point of the i-th target trajectory is η r(i-1) The end point is η ri , Indicates that the starting point of the last target trajectory is The end point is the target location.

6. The fault-tolerant control method for an unmanned boat based on path planning as claimed in claim 3, characterized in that: Step S3 includes, according to the unmanned boat's dynamic error system, using the unmanned boat's trajectory tracking control law to control the unmanned boat to track the target trajectory set, wherein: The dynamic error system of the unmanned boat is expressed as ξ e =[x e ,y e ,ψ e ,w e ,v e ,r e ],satisfy: among them, x e =x r -x,y e =y r -y,ψ e =ψ r -ψ,w e =w r -w,v e =v r -v,r e =r r -r; The trajectory tracking control law of the unmanned boat is: Among them, a1, a2, a3, a4, a5, and a6 are the control parameters of the control law and satisfy a1>d2-d1 a4>0 a5>-d3 a6＞0。 7. The fault-tolerant control method for an unmanned boat based on path planning as claimed in claim 1, characterized in that: In step S3, the fault-tolerant control steps of the unmanned boat include: Step S31: Determine the current target trajectory; Step S32: Control the unmanned boat to track the current target trajectory, and calculate the distance between the current position of the unmanned boat and the end point of the target trajectory during the tracking period, and determine whether the distance is less than a preset error value. If not, it means that the tracking of the current target trajectory is not completed, and step S32 is repeated; if yes, it means that the tracking of the current target trajectory is completed, and step S33 is executed; Step S33: Determine whether all target trajectories in the target trajectory set have been tracked. If not, take the next target trajectory as the current target trajectory to be tracked and jump to step S32. If yes, it means that the target position has been reached and the tracking is ended.

8. A fault-tolerant control system for an unmanned boat based on path planning, characterized in that: include: A fault identification unit is used to determine whether the unmanned boat has a fault, wherein the unmanned boat cannot move in a straight line, can only turn to one side, and can only move forward but not backward; A trajectory planning unit is used to plan a target trajectory set from a fault start position to a target position according to a dynamic model of the unmanned boat and fault information, wherein the target trajectory set includes a plurality of alternating forward semicircular trajectories and turning semicircular trajectories, wherein the radius of the forward semicircular trajectory is greater than the radius of the turning semicircular trajectory, and the trajectory switching position of the forward semicircular trajectory and the turning semicircular trajectory is used as a target point, and the forward semicircular trajectory and the turning semicircular trajectory are tangent to each other at the target point, and all target points are located on a straight line from the fault start position to the target position; A trajectory tracking unit, used to control the unmanned boat to track the target trajectory set, and when the unmanned boat reaches the target point, the next semicircle trajectory is tracked as a new target trajectory until the tracking of all target trajectories in the target trajectory set is completed; The dynamic model of the unmanned boat is: Among them, (x, y) represents the position coordinates of the unmanned boat, ψ represents the heading of the unmanned boat, w, v, r represent the longitudinal velocity, sway velocity and angular velocity respectively, τ u , τ r represent the propeller power and the steering angle respectively, d1, d2, d3 are the hydrodynamic damping coefficients during longitudinal surge, transverse sway and bow pitch respectively, m1, m2, m3 are the inertial masses of the additional mass effects of the unmanned boat in the transverse, longitudinal and heading directions respectively; The fault information of the unmanned boat is expressed as: are respectively the propeller power and steering angle when tracking the target trajectory, where 0≤τ u ≤τ umax , τ umax is the maximum power that the thruster can achieve, when 0<τ rmin ≤τ r ≤τ rmax , indicating that the unmanned boat can only turn right, (τ rmin ,τ rmax ) is the turning angle range for turning right, when τ' rmin ≤τ r ≤τ' rmax <0, indicating that the unmanned boat can only turn left, (τ' rmin ,τ' rmax ) is the steering angle range for turning left.

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