An unmanned sailboat motion control method with wind sail input restriction

Abstract

The application provides a kind of unmanned sailer motion control method with wind sail input restriction.The method of the application comprises: constructing the kinematics model of unmanned sailer, and performing dynamics reasoning;based on the constructed kinematics model of unmanned sailer, designing the lower boundary of wind sail power control input restriction of discrete system;based on the non-parametric dynamic linearization technology, converting the sailer course control into full-format equivalent data model, and applying MFAC to control the course.The application considers that unreasonable sail angle will exert larger overturning moment on sailer, so that the attitude of sailer will change greatly, which will not only affect the dynamic performance of sailer, but also exist the risk of hull overturning.Therefore, the sailer roll constraint model is constructed for discrete system to solve the problem of wind sail controller input restriction.Meanwhile, the full-format non-model adaptive control technology is applied to unmanned sailer navigation control system for rudder angle control, to solve the problems of unknown model of unmanned sailer and poor transient response.

Description

Technical Field

[0001] This invention relates to the field of unmanned sailboat technology, and more particularly to a motion control method for unmanned sailboats with limited sail input. Background Technology

[0002] The interaction of multiple ocean spheres is a current research hotspot in marine science. Space-based observation technologies cannot collect in-situ data, sea-based observation technologies have limited spatial freedom, and underwater observation technologies have limited observation range and weak surface observation capabilities. These technologies cannot meet the demands for continuous acquisition of long-duration, large-scale observation data of the air-sea interface. Unmanned sailboats have shown great potential in acquiring sea surface meteorological elements and shallow-water hydrological information, providing observational methods and advanced platform support for comprehensive three-dimensional ocean observation and marine environmental safety assurance. Therefore, research on the motion control of unmanned sailboats has long-term application value.

[0003] Depending on the control objective, the control of unmanned sailboats can be divided into two categories: speed control, which aims to maximize or achieve a specific speed, and course control, which aims to keep the sailboat along a reference course. The former is achieved by controlling the sail's spread angle, while the latter is achieved by controlling the rudder angle. Speed ​​control of a sailboat involves adjusting the optimal angle of attack at a specific wind angle and wind speed to achieve maximum acceleration while ensuring the heel angle remains within a safe range; this is essentially a thrust optimization or sail angle optimization problem. Polar coordinate graphs can be used to describe the maximum theoretical speed under a specific course and the unnavigable areas.

[0004] Significant progress has been made internationally in optimizing sailboat speed. For example, sail angle is controlled using polar coordinate curves and the aerodynamic characteristics of the sail; the "Guaranteed Set Inwersion" algorithm calculates the extreme value search curve under a precise mathematical model of sailboat motion, serving as a feedforward compensator to guide the controller; a "hill-climbing algorithm" is used for online optimization of the sail angle, allowing for a small adjustment at each sampling time and recording the velocity response at the next moment; the product of the signs of these two adjustments represents the gradient direction of the sail angle relative to the forward velocity; and an "extreme value search algorithm" is used to search for the optimal angle of attack in real time, with the feedforward compensator designed based on human experience. To overcome the steady-state buffeting inherent in traditional ES algorithms, a sail controller based on a fuzzy control system is proposed, with the sailboat's roll angle as the input. This algorithm can prevent the sailboat from capsizing due to excessive sail torque. Domestic research has also focused on improving the ES algorithm, designing a steady-state oscillation-free ESC speed optimization scheme to suppress buffeting. Most of the aforementioned research findings either fail to consider the heel constraint of the sailboat or integrate the heel problem with controller design, resulting in input-constrained solutions lacking general applicability. One event-triggered adaptive fuzzy control scheme transforms the heel constraint into sail input saturation. Building upon these findings, this project will conduct further research on the discrete model-based research object.

[0005] The heading control of unmanned sailboats can generally be referenced from the heading control of conventionally powered ships. Internationally, some research has employed FLS (Flexible Linear Controller) to design rudder angle controllers, considering the factor of rudder turning speed; designed PID heading-keeping controllers for sailboats; and, based on the dynamic model of the sailboat's bow, designed a backstepping control law for the rudder angle under the assumption that unknown dynamics remain constant, and performed online estimation of the unknown dynamics. For the motor-driven "Prindle-19" model, a Kalman observer was used for parameter identification, and a linear quadratic Gaussian controller was designed. Furthermore, regarding the modeling problem of unmanned sailboats, some research has applied Newton-Euler equations, Lagrange equations, and wing theory to establish a 4-DOF sailboat model, and designed a heading-keeping controller based on the model using an integral backstepping method; designed a neutral balance heading-keeping controller for a sailboat under a precise model using "flatness" theory and the backstepping method; and simplified the bow-turning dynamics of the sailboat to a Nomoto model, using a model reference adaptive method to design a controller, which exhibits superior robustness compared to PID and backstepping methods. Among domestic research teams, some researchers started by designing a neural network adaptive dynamic surface heading-keeping controller for sailboats, using the Nussbaum function to handle the problem of unknown control gain direction. Based on this research, other researchers further introduced auxiliary systems and S-functions to handle the problem of limited rudder angle input.

[0006] Existing research largely focuses on course-maintaining control for unmanned sailboats, with limited research on path-following control for real-time course updates. Furthermore, due to the complex nonlinear and strongly coupled characteristics of sailboats, obtaining accurate model data is difficult in practice, thus limiting the application of most model-based control methods. Therefore, the application of data-driven controller design schemes in unmanned sailboats remains a topic worthy of attention and further exploration. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a motion control method for an unmanned sailboat with limited sail input. This invention considers that an unreasonable sail angle can exert a large capsizing moment on the sailboat, causing significant changes in its attitude. This not only affects the sailboat's dynamic performance but can also pose a risk of capsizing. Therefore, a heel constraint model for the discrete system is constructed to solve the problem of limited sail controller input. Simultaneously, for rudder angle control, a full-format model-free adaptive control technique is applied to the unmanned sailboat navigation control system to address the issues of unknown unmanned sailboat model and poor transient response.

[0008] The technical means employed in this invention are as follows:

[0009] A motion control method for an unmanned sailboat with limited sail input includes:

[0010] Construct a kinematic model of an unmanned sailboat and perform dynamic reasoning;

[0011] Based on the constructed kinematic model of the unmanned sailboat, a constrained lower boundary for the sail power control input of the discrete system is designed;

[0012] Based on nonparametric dynamic linearization technology, the sailboat's heading control is transformed into a full-format equivalent data model, and MFAC is applied to control the heading.

[0013] Furthermore, the construction of the kinematic model of the unmanned sailboat and the performance of dynamic reasoning include:

[0014] The kinematic and dynamic models of the unmanned sailboat are constructed as follows:

[0015]

[0016] in, The unmanned sailboat's position in the Earth coordinate system is represented by φ∈(-π / 2,π / 2], which represents its roll angle, and ψ∈(-π,π], which represents its yaw angle. These represent the forward, lateral, roll, and yaw angular velocities of the unmanned sailboat in the ship's coordinate system, respectively. These are the mass matrix, Coriolis moment, rigid body Coriolis matrix, additional mass matrix, and damping matrix, respectively. The restoring torque is represented by S, K, and R, which represent the force matrices of the sail, keel, and rudder, respectively.

[0017] Furthermore, based on the constructed kinematic model of the unmanned sailboat, the design of the constrained lower boundary of the discrete system's sail dynamic control input includes:

[0018] The kinematics and dynamics model of the constructed unmanned sailboat is discretized as follows:

[0019]

[0020] According to the separation principle, F xs,k The dominant forward motion in the discretization formula, M xs,k Dominant lateral roll motion;

[0021] To prevent the sailboat from capsizing, φ k+1 The roll constraint is processed, and a preset threshold is used.

[0022] From the discretization formula, we can know φ k+1 It is p k The decision was made by using a reverse reasoning method to determine p. k The threshold is designed as follows:

[0023]

[0024] when hour,

[0025] In order to make M xs,k The constraint range is designed to be Let the observed values ​​of the relevant unknown variables be... Then we have:

[0026]

[0027] set up Then we get:

[0028] p k+1 > p k -T s μ1

[0029]

[0030]

[0031] In the above formula, as ε k →0,|ιφ,k |→0, This proves that by limiting the roll moment M xs,k This allows the roll angle to converge to within the threshold boundary;

[0032] According to M xs,k and F xs,k The dynamic relationship when M xs,k When restricted, F xs,k Also restricted; without considering roll constraints, |M xs,k |and F xs,k All will follow |α s | increases from 0 to its maximum value as | increases, but the maximum value corresponds to |α. s |Irrelevant; Define α su For |M xs,k The angle of attack corresponding to the maximum value, α sp For F xs,k The angle of attack corresponding to the maximum value is defined as M. xs,k |α corresponding to the constraint boundary s |Threshold is α sl ;

[0033] Set the tilt constraint threshold For min{α sp ,α su ,α sl The corresponding F xs,k The value of, i.e. The roll constraint is converted into the power input saturation of the sail.

[0034] Furthermore, the nonparametric dynamic linearization technique is used to transform the sailboat's heading control into a full-format equivalent data model, and MFAC is applied to control the heading, including:

[0035] Consider an unknown class of nonaffine nonlinear discrete single-input single-output (SISO) nonlinear systems, as follows:

[0036] y(k+1)∈R n = f(y(k),y(k-1),...,y(kn) y ),u(k),u(k-1),...,u(kn u ))

[0037] For unmanned sailboats, course control is mainly achieved by changing the rudder angle, which is equivalent to the system described above. Furthermore, the above assumptions are satisfied, and a PDD exists, allowing the system to be transformed into the following FFDL data model:

[0038]

[0039] in,

[0040] Introduce the performance metric function as follows:

[0041] J(Δu(k))=|e(k+1| 2 +ι|u(k)-u(k-1)| 2

[0042] set up The control input for the rudder angle is obtained as follows:

[0043]

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] 1. The motion control method for unmanned sailboats with limited sail input provided by this invention, which constructs a solution to the problem of limited sailboat input, uses numerical control technology, is applicable to practical discrete sailboat control systems, and verifies the practical feasibility of the conversion relationship between sail angle and roll angle.

[0046] 2. The motion control method for unmanned sailboats with limited sail input provided by this invention uses full-format model-free adaptive control technology, which can achieve the control effect with only the input / output data of the unmanned sailboat, thus eliminating the dependence on the mathematical model of the controlled system.

[0047] 3. The motion control method for unmanned sailboats with limited sail input provided by this invention uses unmanned sailboats with traditional soft sails and ropes for modeling. Its control mechanism and mechanical delay are closer to the actual situation, making the designed control algorithm more adaptable.

[0048] Based on the above reasons, this invention can be widely applied in fields such as unmanned sailboats. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a flowchart of the method of the present invention.

[0051] Figure 2 The simulation diagram of unmanned sailboat path following provided in the embodiment of the present invention.

[0052] Figure 3The path following position error diagram is provided for an embodiment of the present invention.

[0053] Figure 4 The road following heading angle error diagram provided for embodiments of the present invention.

[0054] Figure 5 A diagram of the sail of an unmanned sailboat provided for an embodiment of the present invention.

[0055] Figure 6 The rudder angle diagram of the unmanned sailboat provided for an embodiment of the present invention.

[0056] Figure 7 The roll angle diagram provided for an embodiment of the present invention. Detailed Implementation

[0057] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0060] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0061] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0062] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0063] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0064] like Figure 1As shown, the present invention provides a motion control method for an unmanned sailboat with limited sail input, comprising:

[0065] S1. Construct a kinematic model of an unmanned sailboat and perform dynamic reasoning;

[0066] S2. Based on the constructed kinematic model of the unmanned sailboat, design the lower boundary of the constrained input for the discrete system's sail power control.

[0067] S3. Based on nonparametric dynamic linearization technology, the sailboat's heading control is transformed into a full-format equivalent data model, and MFAC is applied to control the heading.

[0068] In a preferred embodiment of the present invention, step S1, which involves constructing a kinematic model of an unmanned sailboat and performing dynamic reasoning, includes:

[0069] The kinematic and dynamic models of the unmanned sailboat are constructed as follows:

[0070]

[0071] in, The unmanned sailboat's position in the Earth coordinate system is represented by φ∈(-π / 2,π / 2], which represents its roll angle, and ψ∈(-π,π], which represents its yaw angle. These represent the forward, lateral, roll, and yaw angular velocities of the unmanned sailboat in the ship's coordinate system, respectively. These are the mass matrix, Coriolis moment, rigid body Coriolis matrix, additional mass matrix, and damping matrix, respectively. The restoring torque is represented by S, K, and R, which represent the force matrices of the sail, keel, and rudder, respectively.

[0072] In a specific implementation, as a preferred embodiment of the present invention, step S2, based on the constructed kinematic model of the unmanned sailboat, designs a constrained lower boundary for the discrete system's sail dynamic control input, including:

[0073] S21. Discretize the constructed kinematics and dynamics model of the unmanned sailboat as follows:

[0074]

[0075] According to the separation principle, F xs,k The dominant forward motion in the discretization formula, M xs,k Dominant lateral roll motion;

[0076] S22. To prevent the sailboat from capsizing, φ k+1 The roll constraint is processed, and a preset threshold is used.

[0077] S23. From the discretization formula, we can see that φ k+1 It is p k The decision was made by using a reverse reasoning method to determine p. k The threshold is designed as follows:

[0078]

[0079] when hour,

[0080] S24. In order to make M xs,k The constraint range is designed to be Let the observed values ​​of the relevant unknown variables be... Then we have:

[0081]

[0082]

[0083] S25, Let Then we get:

[0084] p k+1 > p k -T s μ1

[0085]

[0086] In the above formula, as ε k →0,|ι φ,k |→0, This proves that by limiting the roll moment M xs,k This allows the roll angle to converge to within the threshold boundary;

[0087] S26, according to M xs,k and F xs,k The dynamic relationship when M xs,k When restricted, F xs,k Also restricted; without considering roll constraints, |M xs,k |and F xs,k All will follow |α s | increases from 0 to its maximum value as | increases, but the maximum value corresponds to |α. s |Irrelevant; Define α su For |M xs,k The angle of attack corresponding to the maximum value, α sp For F xs,k The angle of attack corresponding to the maximum value is defined as M. xs,k |α corresponding to the constraint boundary s |Threshold is α sl ;

[0088] S27. Set the roll constraint threshold. For min{α sp ,α su ,α sl The corresponding F xs,k The value of, i.e. The roll constraint is converted into the power input saturation of the sail.

[0089] In a preferred embodiment of the present invention, step S3 involves converting the sailboat's heading control into a full-format equivalent data model based on nonparametric dynamic linearization technology, and applying MFAC to control the heading, including:

[0090] S31. Consider an unknown class of non-affine nonlinear discrete single-input single-output (SISO) nonlinear systems, as follows:

[0091] y(k+1)∈R n = f(y(k),y(k-1),...,y(kn) y ),u(k),u(k-1),...,u(kn u ))

[0092] S32. For unmanned sailboats, the main control of their course is achieved by changing the rudder angle, which is equivalent to the system described above. Furthermore, the above assumptions are satisfied, and a pdd exists, allowing the system to be transformed into the following FFDL data model:

[0093]

[0094] in,

[0095] S33. Introduce the performance index function as follows:

[0096] J(Δu(k))=|e(k+1| 2 +ι|u(k)-u(k-1)| 2

[0097] S34, Settings The control input for the rudder angle is obtained as follows:

[0098]

[0099] Example

[0100] To verify the effectiveness of the above method, MATLAB was used to perform simulation verification. The specific simulation is as follows: Figure 2-7As shown, unmanned sailboats differ significantly from propeller-driven or waterjet-driven unmanned vessels in their motion mechanism. The motion of unmanned sailboats is greatly affected by wind direction, and their speed is difficult to control (partly due to the difficulty in accelerating, as they are generally controlled to sail at maximum speed, and partly due to the inability to stop abruptly). Furthermore, unmanned sailboats lack the ability to move in all directions, and obtaining an accurate model of the unmanned sailboat system is difficult in practice. This leads to differences and complexities in the navigation path and navigation control of unmanned sailboats. On the other hand, model-free adaptive control technology, due to its characteristic of relying solely on input / output data, demonstrates good control performance in addressing the unknown model of unmanned sailboat systems and overcoming system uncertainties, unmodeled dynamics, and the influence of external disturbances. Therefore, research on the motion control of unmanned sailboats has significant theoretical and practical implications.

[0101] In summary, this invention mainly addresses the motion control of unmanned sailboats. It proposes a scheme for transforming the roll constraint of unmanned sailboats into control input boundaries from two aspects: sail control input and rudder angle control input. Furthermore, it applies a model-free adaptive controller to solve the problems of unknown unmanned sailboat models and complex nonlinearities.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A motion control method for an unmanned sailboat with limited sail input, characterized in that, include: Construct a kinematic model of the unmanned sailboat and perform dynamic reasoning, including: The kinematic and dynamic models of the unmanned sailboat are constructed as follows: in, The unmanned sailboat's position in the Earth coordinate system is represented by φ∈(-π / 2,π / 2], which represents its roll angle, and ψ∈(-π,π], which represents its yaw angle. These represent the forward, lateral, roll, and yaw angular velocities of the unmanned sailboat in the ship's coordinate system, respectively. These are the mass matrix, Coriolis moment, rigid body Coriolis matrix, additional mass matrix, and damping matrix, respectively. This represents the restoring torque; S, K, and R represent the force matrices of the sail, keel, and rudder, respectively. Based on the constructed kinematic model of the unmanned sailboat, a constrained lower boundary for the discrete system's sail dynamic control input is designed, including: The kinematics and dynamics model of the constructed unmanned sailboat is discretized as follows: According to the separation principle, F xs,k The dominant forward motion in the discretization formula, M xs,k Dominant lateral roll motion; To prevent the sailboat from capsizing, φ k+1 The roll constraint is processed, and a preset threshold is used. From the discretization formula, we can know φ k+1 It is p k The decision was made by using a reverse reasoning method to determine p. k The threshold is designed as follows: when hour, In order to make M xs,k The constraint range is designed to be Let the observed values ​​of the relevant unknown variables be... Then we have: set up Then we get: p k+1 > p k -T s μ1 In the above formula, as This proves that by limiting the roll moment M xs,k This allows the roll angle to converge to within the threshold boundary; According to M xs,k and F xs,k The dynamic relationship when M xs,k When restricted, F xs,k Also restricted; without considering roll constraints, |M xs,k |and F xs,k All will follow |α s | increases from 0 to its maximum value as | increases, but the maximum value corresponds to |α. s |Irrelevant; Define α su For |M xs,k The angle of attack corresponding to the maximum value, α sp For F xs,k The angle of attack corresponding to the maximum value is defined as M. xs,k |α corresponding to the constraint boundary s |Threshold is α sl ; Set the tilt constraint threshold For min{α sp ,α su ,α sl The corresponding F xs,k The value of, i.e. Convert the roll constraint into saturated power input for the sail; Based on nonparametric dynamic linearization technology, the sailboat's heading control is transformed into a full-format equivalent data model, and MFAC is applied to control the heading.

2. The motion control method for an unmanned sailboat with limited sail input according to claim 1, characterized in that, The nonparametric dynamic linearization technique transforms the sailboat's heading control into a full-format equivalent data model, and applies MFAC to control the heading, including: Consider an unknown class of non-affine nonlinear discrete single-input single-output nonlinear systems, as follows: y(k+1)∈R n =f(y(k),y(k-1),...,y(k-n y ),u(k),u(k-1),...,u(k-n u )) For unmanned sailboats, course control is mainly achieved by changing the rudder angle, which is equivalent to the system described above. Furthermore, the above assumptions are satisfied, and a PDD exists, allowing the system to be transformed into the following FFDL data model: in, Introduce the performance metric function as follows: J(Δu(k))=|e(k+1)| 2 +ι|u(k)-u(k-1)| 2 set up The control input for the rudder angle is obtained as follows:

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