Underactuated surface vessel finite-time path following anti-windup output feedback control method
Patent Information
- Application Number
- CN202610818930.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-08
- Publication Date
- 2026-08-18
AI Technical Summary
现有欠驱动水面船路径跟踪通常采用“LOS导引（或SF坐标误差建模）+反步/滑模/自适应等控制器”的框架，并辅以扰动观测器或扩张状态观测器以提升鲁棒性；然而在实际工程中普遍存在模型不确定、风浪流等未知外界扰动、速度测量缺失或不可靠以及推进/舵机输入饱和等约束，使得现有技术暴露出以下问题：一是多数方法对速度等状态测量依赖较强，在仅有位置信息的输出反馈条件下，速度与扰动估计往往为渐近收敛或收敛较慢，导致过渡过程长、误差难以快速压缩到较小范围，跟踪精度与鲁棒性下降；二是现有控制多以渐近稳定为主，难以满足复杂工况下对快速收敛与高精度的要求，路径跟踪时间长且易出现误差衰减慢、抗扰不足等现象；三是对输入饱和的处理常停留在经验限幅或简单补偿层面，饱和发生时控制指令被截断易引发性能劣化、误差反弹甚至闭环振荡，且在扰动未知与输出反馈条件下更难给出可证明的稳定性与精度保证
1、本发明可以实现欠驱动水面船在模型不确定、未知外界环境干扰、速度测量值未知以及执行器输入饱和的情况下，欠驱动水面船能进一步提高欠驱动水面船的路径跟踪精度以及系统的抗干扰能力，实现欠驱动水面船在有限时间内路径跟踪控制。
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Figure CN122592856A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of underactuated surface vessel technology, specifically relating to a finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels. Background Technology
[0002] Underactuated surface vessels (SSVs) are widely used in tasks such as waterway patrol, surveying and monitoring, and emergency rescue due to their simple structure, low energy consumption, and convenient maintenance. Path tracking control is a key technology for achieving autonomous navigation. Existing path tracking for SSVs typically employs a framework of "LOS guidance (or SF coordinate error modeling) + backstepping / sliding mode / adaptive controllers," supplemented by disturbance observers or extended state observers to improve robustness. However, in practical engineering, constraints such as model uncertainty, unknown external disturbances like wind, waves, and currents, missing or unreliable velocity measurements, and propulsion / steering input saturation are common, leading to the following problems with existing technologies: First, most methods heavily rely on state measurements such as velocity. Under conditions where only position information is available as output feedback, velocity and disturbance estimates are often asymptotic. First, slow convergence leads to a long transition process, making it difficult to quickly compress errors to a smaller range, resulting in decreased tracking accuracy and robustness. Second, existing control systems are mostly based on asymptotic stability, which is difficult to meet the requirements for rapid convergence and high accuracy under complex operating conditions. Path tracking time is long and prone to slow error decay and insufficient disturbance rejection. Third, the handling of input saturation often remains at the level of empirical limiting or simple compensation. When saturation occurs, the control command is truncated, which can easily lead to performance degradation, error rebound, or even closed-loop oscillation. Moreover, it is even more difficult to provide provable stability and accuracy guarantees under unknown disturbance and output feedback conditions. Summary of the Invention
[0003] To address the problems existing in the prior art, this invention provides a finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels. This method enables the path tracking error of the underactuated surface vessel to converge to an arbitrarily small neighborhood of zero within a finite time, even under conditions of model uncertainty, unknown external environmental disturbances, unknown velocity measurements, and actuator input saturation. Compared to the traditional asymptotic path tracking output feedback control method, this method not only has a faster convergence speed and higher control accuracy but also stronger anti-interference capability.
[0004] To achieve the above objectives, the present invention provides the following solution: A finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels includes: Step S1: Establish an underactuated surface vessel model; Step S2: Based on the fact that underactuated surface ships have model uncertainties, unknown external environmental disturbances, unknown speed measurements, and actuator input saturation, a finite-time extended state observer is constructed to observe the ship's speed and the combined disturbances of unknown environmental disturbances within a finite time based solely on the ship's position measurement information. Step S3: By combining the LOS guidance method with the Serret-Frenet (SF) coordinate frame, the error model of path tracking is derived using the SF coordinate frame. Furthermore, based on the velocity values observed by the finite-time extended state observer, a finite-time LOS guidance law based on the velocity observation values is designed to obtain the desired virtual control law. Step S4: Based on the finite-time extended state observer and the desired virtual control law, and using the backstepping method combined with finite-time theory, obtain the finite-time heading tracking anti-saturation output feedback controller. Finite-time velocity tracking anti-saturation output feedback controller Used to track the desired heading angle and the expected speed Unknown synthetic interference in the system and A finite-time disturbance observer was used for estimation; robust path-following control of an underactuated surface vessel was achieved.
[0005] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention enables underactuated surface vessels to further improve path tracking accuracy and anti-interference capability under conditions of model uncertainty, unknown external environmental interference, unknown speed measurement values, and actuator input saturation, thereby achieving path tracking control of underactuated surface vessels within a finite time.
[0006] 2. This invention enables underactuated surface vessels to converge their path tracking error to an arbitrarily small neighborhood of zero within a finite time when the speed measurement value is unknown, thereby shortening the path tracking time and ensuring that the closed-loop system has better robustness.
[0007] 3. The controller designed in this invention has a faster convergence speed, higher tracking accuracy, and stronger anti-interference capability. Attached Figure Description
[0008] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0009] Figure 1 This is a schematic diagram illustrating the principle of the finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels according to an embodiment of the present invention.
[0010] Figure 2 A schematic diagram defining the path tracking framework for underactuated surface vessels. Detailed Implementation
[0011] 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. 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.
[0012] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0013] Example 1 like Figure 1 As shown, the present invention provides a finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels, comprising: Step S1: Establish an underactuated surface vessel model; Step S2: Based on the fact that underactuated surface ships have model uncertainties, unknown external environmental disturbances, unknown speed measurements, and actuator input saturation, a finite-time extended state observer is constructed to observe the ship's speed and the combined disturbances of unknown environmental disturbances within a finite time based solely on the ship's position measurement information. Step S3: By combining the LOS guidance method with the Serret-Frenet (SF) coordinate frame, the error model of path tracking is derived using the SF coordinate frame. Furthermore, based on the velocity values observed by the finite-time extended state observer, a finite-time LOS guidance law based on the velocity observation values is designed to obtain the desired virtual control law. Step S4: Based on the finite-time extended state observer and the desired virtual control law, and using the backstepping method combined with finite-time theory, obtain the finite-time heading tracking anti-saturation output feedback controller. Finite-time velocity tracking anti-saturation output feedback controller Used to track the desired heading angle and the expected speed Unknown synthetic interference in the system and A finite-time disturbance observer is used for estimation. Robust path-following control for underactuated surface vessels is achieved.
[0014] As one embodiment of the present invention, in step S1, since the six-degree-of-freedom model of a ship is very complex, it is not suitable for underactuated surface ships with special structures. To facilitate the research on path tracking control of underactuated surface ships, the six-degree-of-freedom model of the ship needs to be simplified without affecting the practicality of the research content. The underactuated surface ship model under uncertainties and unknown external environmental disturbances is as follows: Wherein, the velocity state vector of the underactuated surface vessel in the BF coordinate system is: ,in, , , These represent the surge velocity, sway velocity, and bow angular velocity, respectively. The position and state vector of an underactuated surface vessel in the NED coordinate system. ,in, These represent the north and east positions of the underactuated surface vessel in the NED coordinate system, respectively. The heading angle represents the heading angle of an underdriven surface vessel, which is the angle between the bow direction and true north in the NED coordinate system. This represents the transformation matrix from the BF coordinate system to the NED coordinate system. . Represents the system's inertia matrix; Represents the Coriolis centripetal force matrix; Represents the ship's hydrodynamic damping coefficient matrix; This indicates the input quantity of the actuator. , These represent longitudinal thrust and bow moment, respectively, while lateral thrust is zero. This indicates interference from external environmental factors such as wind, waves, and currents. The underactuated surface vessel model under uncertainties and unknown external environmental disturbances can also be expressed in the following form: in, , , , It is an uncertain function, which includes unmodeled dynamics and uncertainties in model parameters.
[0015] As one embodiment of the present invention, when a ship moves horizontally, the external environmental disturbances acting on the ship are caused by the ocean environment's wind, waves, and currents, and their rate of change is bounded in practical engineering applications. In step S2, it is assumed that the rate of change of the composite disturbance, composed of unmodeled dynamics, uncertain model parameters, and unknown external environmental disturbances, is bounded, i.e., it satisfies... ,in, It is a normal number.
[0016] Furthermore, the specific process of step S2 is as follows: make , , Let the finite-time extended state observer be as follows: in, , , This represents the observation error of the extended state observer. , For the design parameters of the extended state observer, , , , , It is a symbolic function.
[0017] In one embodiment of the present invention, in step S3, for the path tracking control problem of underactuated surface vessels, an error model for path tracking is derived using the SF coordinate frame in conjunction with a motion mathematical model. The path tracking control problem of underactuated surface vessels is described as follows: Figure 2 As shown. The dynamics of the path tracking error of an underactuated surface vessel based on velocity observations in the SF coordinate system are as follows: in, , The path parameter update law, desired heading angle, and virtual control law are as follows: in, It refers to the forward sight distance in the guidance method. , , , These are design parameters. , , The expression is as follows: In one embodiment of the present invention, step S4 of the finite-time path tracking output feedback control subsystem comprises two parts: (1) a finite-time heading tracking anti-saturation output feedback controller; and (2) a finite-time speed tracking anti-saturation output feedback controller. In this invention, the finite-time path tracking anti-saturation output feedback controller is designed using the backstepping method, based on finite-time theory. Finite-time velocity tracking anti-saturation output feedback controller Used to track the desired heading angle and desired longitudinal velocity Unknown synthetic interference in the system , The estimation is performed using a finite-time disturbance observer. The specific process is as follows: (1) Finite-time heading tracking anti-saturation output feedback controller based on velocity observations Depend on It can be known ,so The heading angular velocity tracking error based on velocity observations is defined as follows: Combined with finite-time extended state observer The dynamic error for tracking the bow angular velocity based on velocity observations is defined as follows: To stabilize the dynamic error of the finite-time heading angular velocity tracking based on velocity observations and to prevent actuator input saturation, the finite-time heading tracking control law based on velocity observations is as follows: (2) Finite-time velocity tracking anti-saturation output feedback controller based on velocity observations Define the speed tracking error based on speed observations as: in, The desired longitudinal velocity.
[0018] To stabilize the dynamic error of speed tracking based on speed observations and prevent actuator input saturation, the speed tracking control law based on speed observations is as follows: in, , , It controls the design parameters. The expression is: In summary, under conditions of uncertainty in the underactuated surface vessel model, unknown external environmental disturbances, unknown speed measurements, and actuator input saturation, the FTESO-based finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels enables rapid path tracking control of the underactuated surface vessel even with unknown speed measurements. Furthermore, it allows the vessel to track the desired path at the desired speed within a finite time, with the tracking error approaching zero within that time. Both the system state variables and the control law exhibit good convergence performance.
[0019] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels, characterized in that, include: Step S1: Establish an underactuated surface vessel model; Step S2: Based on the underactuated surface ship model, construct a finite-time extended state observer; Step S3: Based on the finite-time extended state observer, obtain the virtual control law to achieve the desired result; Step S4: Based on the finite-time extended state observer and the desired virtual control law, and using the backstepping method combined with finite-time theory, obtain the finite-time heading tracking anti-saturation output feedback controller. Finite-time velocity tracking anti-saturation output feedback controller The and Used to track the desired heading angle and the expected speed Among them, unknown synthetic interference in the system and The estimation is performed using a finite-time disturbance observer.
2. The finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels as described in claim 1, characterized in that, The underactuated surface vessel model in step S1 is: in, , , , It is an uncertain function, which includes unmodeled dynamics and uncertainties in model parameters.
3. The finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels as described in claim 2, characterized in that, In step S2, the ship's speed and the combined interference of unknown environmental disturbances are observed within a finite time using a finite-time extended state observer based solely on the ship's position measurement information.
4. The finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels as described in claim 3, characterized in that, In step S3, the error model for path tracking is derived using the SF coordinate frame, and a finite-time LOS guidance law based on the velocity observation value is designed according to the velocity value observed by the finite-time extended state observer to obtain the desired virtual control law.
5. The finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels as described in claim 4, characterized in that, In step S2, let , , Let the finite-time extended state observer be as follows: in, , , This refers to the observation error of the extended state observer; , For the design parameters of the extended state observer, , , , , It is a symbolic function.
6. The finite-time path tracking anti-saturation output feedback control method for underactuated surface vessels as described in claim 5, characterized in that, In step S3, the dynamic path tracking error of the underactuated surface vessel based on velocity observations in the SF coordinate system is as follows: in, , The path parameter update law, desired heading angle, and virtual control law are as follows: in, It refers to the forward sight distance in the guidance method. , , , These are design parameters. , , The expression is as follows: 。