Fault-tolerant control method and control system of unmanned boat based on spiral strategy

Abstract

The present invention discloses a fault-tolerant control method and system for an unmanned boat based on a spiral strategy. When the unmanned boat is subject to monotonic heading constraints, the following steps are performed: calculating the moving direction φ(t) and the position average value P(t) of the unmanned boat in the current heading angle cycle; calculating the position average value P(t) and the target position η f The deviation direction φ d (t); calculate the angular error ε(t) in the moving direction and the deviation direction through the formula #imgabs0#; calculate the angular error ε(t) in the moving direction and the deviation direction through the formula ψ r (t)=φ(t)+ε(t)‑α 2 (φ(t)‑φ d (t)) Calculate the adjustment angle ψ of the next heading angle cycle r (t); Divide the heading angle period into the angle adjustment area 2kπ+ψ r (t)-ψ f ,2kπ+ψ r (t)+ψ f and the acceleration zone 2kπ+ψ r (t)+ψ f ,(2k+2)π+ψ r (t)-ψ f , increase the propeller power and reduce the steering angle in the angle adjustment area, and reduce the propulsion power and increase the steering angle in the acceleration area. Through the above method, the azimuth angle of the unmanned boat can be controlled to ensure that the unmanned boat can spirally move toward the target position.

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 a spiral strategy and a control system thereof. Background Art

[0002] In recent decades, unmanned vehicles (USVs) have been widely used in water quality monitoring, military reconnaissance, marine exploration and other fields due to their high efficiency, high flexibility and low operating cost. In related water missions, USVs have a high operating load and are often disturbed by the harsh external environment, which causes the actuators of the USVs to often fail. This means that the control input is always limited to positive or negative, the actuator cannot be zeroed, and the USV cannot move in a straight line. In this case, the return mission of the USV becomes very challenging. At present, the fault-tolerant control problem of such USV devices has not been well solved. Summary of the invention

[0003] 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 a spiral strategy, which aims to solve the problem of navigation and return to port of a faulty unmanned boat with a monotonic heading constraint.

[0004] To achieve the above object, according to one aspect of the present invention, a fault-tolerant control method for an unmanned boat based on a spiral strategy is provided. When the unmanned boat cannot travel in a straight line, can only turn to one side, and can only move forward but not backward, the following steps are executed:

[0005] Calculate the moving direction φ(t) of the unmanned boat in the current heading angle cycle, where each heading angle cycle is 2π;

[0006] Calculate the average position P(t) of the unmanned boat in the current heading angle cycle;

[0007] Calculate the average position P(t) and the target position η f The deviation direction φ d (t);

[0008] By formula Calculate the angular error ε(t) between the moving direction and the deviation direction;

[0009] Through the formula ψ r (t)=φ(t)+ε(t)-α2(φ(t)-φ d (t)) Calculate the adjustment angle ψ of the next heading angle cycle r (t); α1>0, α2>0 are control parameters;

[0010] Divide the heading angle period into the angle adjustment area 2kπ+ψ r (t)-ψf ,2kπ+ψ r (t)+ψ f and the acceleration zone 2kπ+ψ r (t)+ψ f ,(2k+2)π+ψ r (t)-ψ f ,in, represents the kth heading angle cycle, ψ f ∈[0,2π] represents the set offset angle, which increases the propeller power and reduces the steering angle in the angle adjustment area, and reduces the propulsion power and increases the steering angle in the acceleration area.

[0011] In one embodiment, the calculation formula of the moving direction φ(t) of the unmanned boat in the current heading angle period is:

[0012]

[0013] Among them, ψ(t) is the heading angle of the unmanned boat at time t, x(t) and y(t) represent the horizontal and vertical coordinates of the unmanned boat at time t, respectively.

[0014] In one embodiment, the calculation formula of the position average value P(t) of the unmanned boat in the current heading angle cycle is:

[0015]

[0016]

[0017]

[0018] in, are the horizontal and vertical coordinates of the average position P(t), ψ(t) is the heading angle of the unmanned boat at time t, x(s), y(s) are the horizontal and vertical coordinates of the unmanned boat at time s.

[0019] In one embodiment, the propeller power τ is controlled within the angle adjustment region. u (t) is τ u , steering angle τ r (t) is Controlling propulsion power τ in the acceleration zone u (t) is Steering angle τ r (t) is τ r , and * Respectively represent the preset upper and lower bounds of the variable*.

[0020] In one embodiment, the heading angle period is divided into an angle adjustment area and an acceleration area by a region separation function, and the region separation function is:

[0021]

[0022] Thruster power τ u The calculation formula is:

[0023]

[0024] Steering angle τ r The calculation formula is:

[0025]

[0026] Among them, ψ(t) is the heading angle of the unmanned boat at time t, and λ>>0 is the design parameter.

[0027] In one embodiment, the method further includes determining the dynamic model of the unmanned boat as:

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034] Among them, x(t), y(t), ψ(t) represent the position coordinates and heading angle of the unmanned boat. m1, m2, m3 are the inertial masses of the additional mass effects of the unmanned boat in the lateral, longitudinal and heading directions, d1, d2, d3 are the hydrodynamic damping coefficients during sway, sway and bow rolling, τ u (t), τ r (t) are the thruster power and steering angle, w(t), v(t), r(t) are the longitudinal velocity, sway velocity and angular velocity, respectively.

[0035] In one embodiment, the fault information of the unmanned boat is represented as:

[0036]

[0037] in, They represent the propeller power and steering angle of the unmanned boat during the control period, respectively. when When When , it means that the unmanned boat can only move forward to the left.

[0038] According to another aspect of the present invention, a fault-tolerant control system for an unmanned boat based on a spiral strategy is provided, which is used to control the unmanned boat when the unmanned boat cannot travel in a straight line, can only turn to one side, and can only move forward but not backward, including:

[0039] The moving direction calculation unit is used to calculate the moving direction φ(t) of the unmanned boat in the current heading angle cycle, and each heading angle cycle is 2π;

[0040] A position average value calculation unit, used to calculate the position average value P(t) of the unmanned boat in the current heading angle cycle;

[0041] Angle error calculation unit, used to calculate the angle error through the formula Calculate the angular error ε(t) between the moving direction and the deviation direction;

[0042] Adjustment angle calculation unit, used to divide the heading angle period into angle adjustment areas 2kπ+ψ r (t)-ψ f ,2kπ+ψ r (t)+ψ f and the acceleration zone 2kπ+ψ r (t)+ψ f ,(2k+2)π+ψ r (t)-ψ f ,in, represents the kth heading angle cycle, ψ f ∈[0,2π] represents the set offset angle;

[0043] The actuator control unit is used to increase the propulsion power and reduce the steering angle in the angle adjustment area, and to reduce the propulsion power and increase the steering angle in the acceleration area.

[0044] According to another aspect of the present invention, an electronic device is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0045] According to another aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0046] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0047] The present invention controls the unmanned boat with a monotonic heading constraint fault to spiral forward, and divides each heading angle period of 2π into two ranges: an angle adjustment area and an acceleration area. On this basis, the unmanned boat is fault-tolerantly controlled to achieve that the unmanned boat reduces the forward speed and increases the steering angular velocity in the angle adjustment area, increases the forward speed and reduces the steering angular velocity in the acceleration area, and adjusts the angle ψ in real time according to the angle error with the target position. r (t), keep the unmanned boat moving in a spiral toward the target position, and realize the control of the unmanned boat's operating azimuth. The above method is concise and effective, with clear logic and easy implementation. It provides a new idea for fault-tolerant control of unmanned boats in fault scenarios, solves the problem of accurate return to port when the unmanned boat loses unilateral power or the steering gear fails, improves the stability of unmanned boat mission execution, and contributes to the development of unmanned boat applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A flowchart of the steps of a fault-tolerant control method for an unmanned boat based on a spiral strategy according to an embodiment;

[0049] Figure 2 A schematic diagram of the trajectory of an unmanned boat returning to the port based on a spiral strategy according to an embodiment;

[0050] Figure 3 A schematic diagram of an angle adjustment area and an acceleration area for the heading of an unmanned boat in the fault-tolerant control of an unmanned boat in one embodiment;

[0051] Figure 4 The present invention is a schematic diagram of the trend change of the regional separation function of the fault-tolerant control of the unmanned boat based on the spiral strategy according to an embodiment. DETAILED DESCRIPTION

[0052] 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.

[0053] In one embodiment, it is determined whether the unmanned boat fails during navigation. When the unmanned boat cannot travel in a straight line, can only turn to one side, and can only move forward but not backward, the unmanned boat fault-tolerant control method based on the spiral strategy of the present invention is executed, such as Figure 1 As shown, the control method includes:

[0054] Step S100: Calculate the moving direction φ(t) of the unmanned boat in the current heading angle period and the average position P(t) in the current heading angle period, where each heading angle period is 2π.

[0055] Among them, the unmanned boat always turns to one side, and the heading angle period of the unmanned boat is 2π. Whenever the heading angle of the unmanned boat changes by one cycle, the moving direction φ(t) and the average position value P(t) of the unmanned boat in the current cycle are calculated, where the moving direction φ(t) is the direction from the starting point of the cycle to the end point of the cycle, and the average position value P(t) is the average value of the trajectory position set in the current cycle.

[0056] Specifically, the moving direction φ(t) of the unmanned boat in the current cycle can be calculated by the following formula:

[0057]

[0058] Where ψ(t) is the heading angle of the unmanned boat at time t, x(t) and y(t) represent the horizontal and vertical coordinates of the unmanned boat at time t, respectively. arctan(.) is the inverse tangent function, ψ -1 (.) is the inverse function of the heading angle ψ. Since ψ is monotonically increasing, the inverse function exists. The moving direction of the unmanned boat can be considered as the moving direction of the unmanned boat position when the heading ψ increases by 2π.

[0059] Specifically, the average position P(t) of the unmanned boat in the current heading angle cycle can be calculated by the following formula:

[0060]

[0061]

[0062]

[0063] in, are the horizontal and vertical coordinates of the average position P(t), ψ(t) is the heading angle of the unmanned boat at time t, x(s) and y(s) are the horizontal and vertical coordinates of the unmanned boat at time s, respectively. The moving position of the unmanned boat can be considered as the average value of the position of the unmanned boat in this period when the heading angle ψ increases by 2π.

[0064] Step S200: Calculate the position average value P(t) and the target position η f The deviation direction φ d (t).

[0065] Among them, Figure 2 As shown, the target position η f =(x f ,y f ) is the target point where the unmanned boat is waiting to return to the port, and the position coordinates are known values. After calculating the position average value P(t), we can calculate the position average value P(t) pointing to the target position η f The direction angle is the deviation direction φ d(t).

[0066] Specifically, the deviation direction φ d (t) can be calculated by the following formula:

[0067]

[0068] Step S300: By formula Calculate the angular error ε(t) between the moving direction and the deviation direction, using the formula ψ r (t)=φ(t)+ε(t)-α2(φ(t)-φ d (t)) Calculate the adjustment angle ψ of the next heading angle cycle r (t); α1>0, α2>0 are control parameters. In a specific embodiment,

[0069] In this step, by calculating the moving direction and average position value of the current heading angle cycle, the deviation direction of the average position value and the target position is calculated, and the adjustment angle ψ of the next heading angle cycle after correction is obtained through the deviation direction and the moving direction. r (t).

[0070] Step S400: Divide the heading angle period into angle adjustment areas 2kπ+ψ r (t)-ψ f ,2kπ+ψ r (t)+ψ f and the acceleration zone 2kπ+ψ r (t)+ψ f ,(2k+2)π+ψ r (t)-ψ f ,in, represents the kth heading angle cycle, ψ f ∈[0,2π] represents the set offset angle, which increases the propeller power and reduces the steering angle in the angle adjustment area, and reduces the propulsion power and increases the steering angle in the acceleration area.

[0071] In one embodiment, the fault information of the unmanned boat is represented as:

[0072]

[0073] in, They represent the propeller power and steering angle of the unmanned boat during the control period, respectively. when When When , it means that the unmanned boat can only move to the left front. In specific control, control the propeller power τ in the angle adjustment area u (t) is τ u, steering angle τ r (t) is Controlling propulsion power τ in the acceleration zone u (t) is Steering angle τ r (t) is τ r , and * Respectively represent the preset upper and lower bounds of the variable *. In a specific embodiment, 0≤τ u ≤4000,2≤τ r ≤20.

[0074] When designing a specific controller, the heading angle period can be divided into an angle adjustment area and an acceleration area using a regional separation function. The regional separation function is:

[0075]

[0076] Wherein, ψ(t) is the heading angle of the unmanned boat at time t, and λ>>0 is a design parameter. In a specific embodiment, λ=100. Figure 3 and Figure 4 As shown, for ψ∈(2kπ+ψ r -ψ f ,2kπ+ψ r +ψ f )have For ψ∈(2kπ+ψ r +ψ f ,(2k+2)π+ψ r -ψ f )have is a periodic signal,

[0077] Correspondingly, the thruster power τ u The calculation formula is:

[0078]

[0079] Steering angle τ r The calculation formula is:

[0080]

[0081] At this time, when the heading angle ψ is in the angle adjustment area [2kπ+ψ r -ψ f ,2kπ+ψ r +ψ f ]hour, The propeller power is minimum, the steering angle is maximum, and the unmanned boat turns quickly; the heading angle ψ is in the acceleration zone [2kπ+ψr +ψ f ,(2k+2)π+ψ r -ψ f ]hour, τ r = τ r , the propulsion power is the largest, the steering angle is the smallest, and the unmanned boat sails forward. And r ,ψ f ∈[0,2π].

[0082] In one embodiment, when controlling the unmanned boat, it is also necessary to confirm the dynamic model of the unmanned boat, and its related parameters also satisfy:

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089] Among them, x(t), y(t), ψ(t) represent the position coordinates and heading angle of the unmanned boat. m1, m2, m3 are the inertial masses of the additional mass effects of the unmanned boat in the lateral, longitudinal and heading directions, d1, d2, d3 are the hydrodynamic damping coefficients during sway, sway and bow rolling, τ u (t), τ r (t) are propeller power and steering angle, respectively, w(t), v(t), r(t) represent longitudinal velocity, sway velocity and angular velocity, respectively. In a specific embodiment, the values ​​of the above parameters can be k1=-1.2235, k2=0.95, k3=0.00122, k4=-1.437, k5=-0.105, k6=-1.399, k7=0.043.

[0090] Accordingly, the present application also relates to an unmanned boat fault-tolerant control system based on a spiral strategy, which comprises:

[0091] The moving direction calculation unit is used to calculate the moving direction φ(t) of the unmanned boat in the current heading angle cycle, and each heading angle cycle is 2π.

[0092] The position average value calculation unit is used to calculate the position average value P(t) of the unmanned boat in the current heading angle cycle.

[0093] Angle error calculation unit, used to calculate the angle error through the formula Calculate the angular error ε(t) between the moving direction and the deviation direction.

[0094] Adjustment angle calculation unit, used to divide the heading angle period into angle adjustment areas 2kπ+ψ r (t)-ψ f ,2kπ+ψ r (t)+ψ f and the acceleration zone 2kπ+ψ r (t)+ψ f ,(2k+2)π+ψ r (t)-ψ f ,in, represents the kth heading angle cycle, ψ f ∈[0,2π] represents the set offset angle.

[0095] The actuator control unit is used to increase the propulsion power and reduce the steering angle in the angle adjustment area, and to reduce the propulsion power and increase the steering angle in the acceleration area.

[0096] The unmanned boat fault-tolerant control system is used to implement the above-mentioned unmanned boat fault-tolerant control method. Each unit in the unmanned boat fault-tolerant control system corresponds to the relevant steps of implementing the unmanned boat fault-tolerant control method. The specific details are introduced above and will not be repeated here.

[0097] Accordingly, the present application also relates to an electronic device, which includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program. Specifically, the electronic device can be a controller installed on an unmanned boat, which is used to control the unmanned boat to return to the port to the target position according to the above method when a monotonic heading constraint failure occurs in the unmanned boat.

[0098] Accordingly, the present application also relates to a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are implemented. Specifically, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0099] The present invention controls the unmanned boat with a monotonic heading constraint fault to spiral forward, and divides each heading angle period of 2π into two ranges: an angle adjustment area and an acceleration area. On this basis, the unmanned boat is fault-tolerantly controlled to achieve that the unmanned boat reduces the forward speed and increases the steering angular velocity in the angle adjustment area, increases the forward speed and reduces the steering angular velocity in the acceleration area, and adjusts the angle ψ in real time according to the angle error with the target position. r (t), keep the unmanned boat moving in a spiral toward the target position, and realize the control of the unmanned boat's operating azimuth. The above method is concise and effective, with clear logic and easy implementation. It provides a new idea for fault-tolerant control of unmanned boats in fault scenarios, solves the problem of accurate return to port when the unmanned boat loses unilateral power or the steering gear fails, improves the stability of unmanned boat mission execution, and contributes to the development of unmanned boat applications.

[0100] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are 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 a spiral strategy, characterized in that: When the unmanned boat cannot travel in a straight line, can only turn to one side, and can only move forward but not backward, execute: Calculate the moving direction φ(t) of the unmanned boat in the current heading angle cycle, where each heading angle cycle is 2π; Calculate the average position P(t) of the unmanned boat in the current heading angle cycle; Calculate the average position P(t) and the target position η f The deviation direction φ d (t); By formula Calculate the angular error ε(t) between the moving direction and the deviation direction; Through the formula ψ r (t)=φ(t)+ε(t)-α2(φ(t)-φ d (t)) Calculate the adjustment angle ψ of the next heading angle cycle r (t); α1>0, α2>0 are control parameters; Divide the heading angle period into the angle adjustment area 2kπ+ψ r (t)-ψ f , 2kπ+ψ r (t)+ψ f and the acceleration zone 2kπ+ψ r (t)+ψ f ,(2k+2)π+ψ r (t)-ψ f ,in, represents the kth heading angle cycle, ψ f ∈[0, 2π] represents the set offset angle. In the angle adjustment area, the propulsion power is increased and the steering angle is reduced. In the acceleration area, the propulsion power is reduced and the steering angle is increased.

2. The fault-tolerant control method for an unmanned boat based on a spiral strategy as claimed in claim 1, characterized in that: The calculation formula of the moving direction φ(t) of the unmanned boat in the current heading angle cycle is: Among them, ψ(t) is the heading angle of the unmanned boat at time t, x(t) and y(t) represent the horizontal and vertical coordinates of the unmanned boat at time t, respectively.

3. The fault-tolerant control method for an unmanned boat based on a spiral strategy as claimed in claim 1, characterized in that: The calculation formula for the average position P(t) of the unmanned boat in the current heading angle cycle is: in, are the horizontal and vertical coordinates of the average position P(t), ψ(t) is the heading angle of the unmanned boat at time t, x(s), y(s) are the horizontal and vertical coordinates of the unmanned boat at time s.

4. The fault-tolerant control method for an unmanned boat based on a spiral strategy as claimed in claim 1, characterized in that: Controlling the thruster power τ in the angle adjustment area u (t) is τ u , steering angle τ r (t) is Controlling propulsion power τ in the acceleration zone u (t) is Steering angle τ r (t) is τ r , and * Respectively represent the preset upper and lower bounds of the variable*.

5. The fault-tolerant control method for an unmanned boat based on a spiral strategy as claimed in claim 4, characterized in that: The heading angle cycle is divided into an angle adjustment area and an acceleration area by a regional separation function. The regional separation function is: Thruster power τ u The calculation formula is: Steering angle τ r The calculation formula is: Among them, ψ(t) is the heading angle of the unmanned boat at time t, and λ>>0 is the design parameter.

6. The fault-tolerant control method for an unmanned boat based on a spiral strategy as claimed in claim 1, characterized in that: It also includes determining the dynamic model of the unmanned boat as: Among them, x(t), y(t), ψ(t) represent the position coordinates and heading angle of the unmanned boat. m1, m2, m3 are the inertial masses of the additional mass effects of the unmanned boat in the lateral, longitudinal and heading directions, d1, d2, d3 are the hydrodynamic damping coefficients during sway, sway and bow roll, τ u (t), τ r (t) are the thruster power and steering angle, w(t), v(t), r(t) are the longitudinal velocity, sway velocity and angular velocity, respectively.

7. The fault-tolerant control method for an unmanned boat based on a spiral strategy as claimed in claim 1, characterized in that: The fault information of the unmanned boat is expressed as: in, They represent the propeller power and steering angle of the unmanned boat during the control period, respectively. when When When , it means that the unmanned boat can only move forward to the left.

8. A fault-tolerant control system for an unmanned boat based on a spiral strategy, characterized in that: Used to control the unmanned boat when it cannot travel in a straight line, can only turn to one side, and can only move forward but not backward, including: The moving direction calculation unit is used to calculate the moving direction φ(t) of the unmanned boat in the current heading angle cycle, and each heading angle cycle is 2π; A position average value calculation unit, used to calculate the position average value P(t) of the unmanned boat in the current heading angle cycle; Angle error calculation unit, used to calculate the angle error through the formula Calculate the angular error ε(t) between the moving direction and the deviation direction; Adjustment angle calculation unit, used to divide the heading angle period into angle adjustment areas 2kπ+ψ r (t)-ψ f , 2kπ+ψ r (t)+ψ f and the acceleration zone 2kπ+ψ r (t)+ψ f ,(2k+2)π+ψ r (t)-ψ f ,in, represents the kth heading angle cycle, ψ f ∈[0, 2π] represents the set offset angle; The actuator control unit is used to increase the propulsion power and reduce the steering angle in the angle adjustment area, and to reduce the propulsion power and increase the steering angle in the acceleration area.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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