Caoyang Yu

Robust fuzzy 3D path following for autonomous underwater vehicle subject to uncertainties

This paper addresses a three-dimensional (3D) path following control problem for underactuated autonomous underwater vehicle (AUV) subject to both internal and external uncertainties. A two-layered framework synthesizing the 3D guidance law and heuristic fuzzy control is proposed to achieve robust adaptive following along a predefined path. In the first layer, a 3D guidance controller for underactuated AUV is presented to guarantee the stability of path following in the kinematics stage. In the second layer, a heuristic adaptive fuzzy algorithm based on the guidance command and feedback linearization Proportional-Integral-Derivative (PID) controller is developed in the dynamics stage to account for the nonlinear dynamics and system uncertainties, including inaccuracy modelling parameters and time-varying environmental disturbances. Furthermore, the sensitivity analysis of the heuristic fuzzy controller is presented. Against most existing methods for 3D path following, the proposed robust fuzzy control scheme reduces the design and implementation costs of complicated dynamics controller, and relaxes the knowledge of the accuracy dynamics modelling and environmental disturbances. Finally, numerical simulation results validate the effectiveness of the proposed control framework and illustrate the outperformance of the proposed controller as well. HighlightsA two-layered framework synthesizing the guidance and control is proposed for 3D AUV path following.Robust and heuristic fuzzy path following algorithm is adopted to account for the system uncertainties.Proposed control scheme reduces the design and implementation cost with regard to most existing methods.Case study and quantitative comparison explicitly show the effectiveness of the proposed framework.

Subsea Cable Tracking by Autonomous Underwater Vehicle with Magnetic Sensing Guidance

The changes of the seabed environment caused by a natural disaster or human activities dramatically affect the life span of the subsea buried cable. It is essential to track the cable route in order to inspect the condition of the buried cable and protect its surviving seabed environment. The magnetic sensor is instrumental in guiding the remotely-operated vehicle (ROV) to track and inspect the buried cable underseas. In this paper, a novel framework integrating the underwater cable localization method with the magnetic guidance and control algorithm is proposed, in order to enable the automatic cable tracking by a three-degrees-of-freedom (3-DOF) under-actuated autonomous underwater vehicle (AUV) without human beings in the loop. The work relies on the passive magnetic sensing method to localize the subsea cable by using two tri-axial magnetometers, and a new analytic formulation is presented to compute the heading deviation, horizontal offset and buried depth of the cable. With the magnetic localization, the cable tracking and inspection mission is elaborately constructed as a straight-line path following control problem in the horizontal plane. A dedicated magnetic line-of-sight (LOS) guidance is built based on the relative geometric relationship between the vehicle and the cable, and the feedback linearizing technique is adopted to design a simplified cable tracking controller considering the side-slip effects, such that the under-actuated vehicle is able to move towards the subsea cable and then inspect its buried environment, which further guides the environmental protection of the cable by setting prohibited fishing/anchoring zones and increasing the buried depth. Finally, numerical simulation results show the effectiveness of the proposed magnetic guidance and control algorithm on the envisioned subsea cable tracking and the potential protection of the seabed environment along the cable route.

Path-Following Control of an AUV: Fully Actuated Versus Under-actuated Configuration

The problem of motion control of underwater vehicles in both the fully actuated and under-actuated configurations is often confronted by the marine technology community. This paper presents a nonlinear control method for autonomous underwater vehicles (AUVs) traveling along a planned planar path in both actuation configurations. The common objectives of path-following control for both fully actuated and under-actuated vehicles are described, and the differences in the necessary path-following control designs are analyzed, showing that the side-slip angle of the vehicle plays an important role in the evolution of the dynamics of AUVs with different actuation configurations. Based on the presented analysis, nonlinear controllers for the two types of AUV configurations are proposed, and the inherent characteristics of under-actuation and full actuation are revealed by a dedicated analysis of numerical simulation paradigms, the results of which will be instrumental in guiding marine technology engineers in the practical design and control of AUVs.

Survey on Fuzzy-Logic-Based Guidance and Control of Marine Surface Vehicles and Underwater Vehicles

Fuzzy logic control, due to its simple control structure, easy and cost-effective design, has been successfully employed to the application of guidance and control in robotic fields. This paper aims to review fuzzy-logic-based guidance and control in an important branch of robots—marine robotic vehicles. First, guidance and motion forms including the maneuvering, path following, trajectory tracking, and position stabilization are described. Subsequently, the application of three major classes of fuzzy logic control, including the conventional fuzzy control (Mamdani fuzzy control and Takagi–Sugeno–Kang fuzzy control), adaptive fuzzy control (self-tuning fuzzy control and direct/indirect adaptive fuzzy control), and hybrid fuzzy control (fuzzy PID control, fuzzy sliding mode control, and neuro-fuzzy control) are presented. In particular, we summarize the design and analysis process of direct/indirect adaptive fuzzy control and fuzzy PID control in marine robotic fields. In addition, two comparative results between hybrid fuzzy control and the corresponding single control are provided to illustrate the superiority of hybrid fuzzy control. Finally, trends of the fuzzy future in marine robotic vehicles are concluded based on its state of the art.

Coordinated 3D Path Following for Autonomous Underwater Vehicles via Classic PID Controller

Abstract In this paper we investigate the problem of coordinated path following control of underactuated autonomous underwater vehicles (AUVs) in 3D space. A classic PID controller is adopted to simplify the path following control design by integrating the 3D guidance law for individual AUVs. Leader-follower strategy is subsequently proposed to coordinate two underactuated AUVs flying along predefined paths in 3D space based on invariant manifold principle, where the speed of the follower is adapted in terms of the single-variant information “along-path parameter” exchanged by the leader vehicle. Simulation results of coordinated path following of underactuated AUVs in 3D space are presented and further research interests are discussed.

Adaptive Fuzzy Trajectory Tracking Control of an Under-Actuated Autonomous Underwater Vehicle Subject to Actuator Saturation

This paper focuses on vertical-plane trajectory tracking of an under-actuated autonomous underwater vehicle (AUV) subject to actuator saturation and external disturbances. A successive guidance and control frame is designed to avoid the cascade analysis between the kinematics guidance and the dynamics control, and the complete Lyapunov function is chosen to analyze the asymptotic stability of trajectory tracking system. In the guidance loop, the line-of-sight guidance law is applied to trajectory tracking of AUVs, which transforms the depth tracking error into the elevation angle tracking error and solves the problem of the under-actuated configuration in heave. In the control loop, direct adaptive fuzzy control is adopted to compensate for the effect of actuator saturation, which guarantees the system stability of trajectory tracking in the presence of actuator saturation. Finally, comparative numerical simulations are provided to illustrate the robust and bounded performance of the designed trajectory tracking control system.

3D path following for under-actuated AUV via nonlinear fuzzy controller

This paper adopts guidance and control framework to address the problem of path following for an under-actuated autonomous underwater vehicle (AUV) moving in three dimensional (3D) space. First, based on the error dynamics in the moving path frame, the desired pitch angle and yaw angle are designed in kinematics by 3D Line-of-Sight (LOS) guidance law. Subsequently, the desired pitch and yaw angular speeds are further derived by Lyapunovs direct method. And then, a model-based nonlinear fuzzy controller is designed in kinetics to force the steerable surge linear speed, pitch and yaw angular speeds of the under-actuated AUV to attain their desired values, such that the AUV converges to and follows the desired 3D path with its resultant speed aligned with the tangent vector of the path. Finally, numerical simulations illustrate the satisfactory 3D following performance of the proposed nonlinear fuzzy controller.

Underwater cable tracking control of under-actuated AUV

In this paper, a cascaded framework including simplified cable localization method with magnetic sensing and robust tracking control algorithm is proposed in order to guide a three-degrees-of-freedom (3-DOF) under-actuated autonomous underwater vehicle (AUV) to autonomously track the underwater cable. With the magnetic sensing, the cable tracking control is constructed as a straight-line path following control problem in the horizontal plane. A simplified magnetic line-of-sight (LOS) guidance is built based on the relative geometric relationship between the AUV and the cable, and a proportional-integral-derivative (PID) controller based on the feedback linearizing technique is adopted to robustly track the desired guidance profiles, such that the under-actuated AUV exposed to constant current disturbances is able to move towards the underwater cable and then inspect its buried environment. Finally, numerical simulation results show the effectiveness of the proposed control system on the cable tracking and inspection.

Coordinated formation control of autonomous underwater vehicles based on leader-follower strategy

This paper presents the problem of steering a group of autonomous underwater vehicles (AUVs) along predefined paths in a desired formation shape. Three types of multiple paths for coordinated formation control of multiple AUVs, shifted paths, parallel paths and arbitrary paths are introduced. By employing the classic path following control method and leader-follower strategy, a team of AUVs are able to follow predefined parallel paths and build the desired inter-vehicle geometric formation in the leaders guide. Numerical examples show the efficiency of the proposed formation control framework based on leader-follower strategy for a group of underwater vehicles following parallel paths.

3D heuristic path following for under-actuated autonomous underwater vehicle with bounded controls and control rates

This paper addresses the problem of three dimensional (3D) path following control for an under-actuated autonomous underwater vehicle (AUV) with bounded controls and control rates. In order to prevent out-of-range control inputs from generating and acting on actuators of the AUV, 3D Line-of-Sight (LOS) guidance law and a heuristic bounded controller are applied to the control system. First, the desired pitch and yaw angles are derived from LOS guidance law in kinematics. And then, the desired pitch and yaw angular velocities are obtained based on Lyapunov stability theorem. Subsequently, a model-independent heuristic controller is designed in kinetics to force the steerable velocities of the AUV with actuator saturation to attain their desired profiles, such that the AUV converges to and follows the desired path with its resultant velocity aligned with the tangent of the path. Finally, simulation cases illustrate the satisfactory performance of the proposed control framework as well as heuristic controller subject to actuator saturation.