Control System For Underwater Vehicle Research Articles

Synthetic data formation for machine learning recognition of underwater objects

The main problem of machine learning for control systems of unmanned underwater vehicles is objectively very small samples of real data. The study aim was to develop an approach to the creation of synthetic data describing underwater objects for as the samples for training and validation in machine learning of control systems for auton-omous unmanned underwater vehicles. The subject of the study was a variety of underwater objects because real information about the shape, size and their external images is very limited. The data augmentation method was used, which makes it possible to obtain additional data on underdetermined objects of observation from the initial data while maintaining the classification features. Eight models have been developed that imitate the influence of various factors of the aquatic environment and allow using various augmentation methods (changing the position, adding noise, glare to the image, defocusing to create fuzziness; fragmentation, etc.) to obtain an almost unlimited number of images of any objects of man-made activity immersed in underwater environment, to varying degrees similar to the reference. Examples of the use of augmentation models that take into account changes in illumina-tion, transparency and the presence of an underwater landscape are given. Such synthetic (model) images may be the basis of a training set for machine learning to recognize and identify underwater objects. The trained model can be used as the basis of a decision support system for operators of remote-controlled unmanned underwater vehicles and as the basis for building control systems for autonomous uninhabited underwater vehicles for moni-toring underwater spaces.

The depth-keeping performance of autonomous underwater vehicle advancing in waves integrating the diving control system with the adaptive fuzzy controller

This study aims to develop an experimental-based adaptive fuzzy controller for the diving control system (DCS) of autonomous underwater vehicle (AUV) to ensure high stability and rapid integration. The DCS is designed with a depth sensor and an attitude and heading reference system (AHRS) to sense the attitude vector and the current depth of AUV in real-time as the control inputs of attitude close-loop and to calculate yaw and pitch controls of AUV. Therefore, the DCS can integrate depth-keeping and attitude stability controls into the AUV. To verify the robustness and adaptability of the DCS with adaptive fuzzy control, the DCS with universal fuzzy control (A-type DCS), improved fuzzy control (B-type DCS), and adaptive fuzzy control (C-type DCS) have been analyzed. The experimental analysis indicates that the C-type DCS features higher robustness to external force interference than the other types of DCS. The present study establishes an adaption function based on depth-keeping control experiments and demonstrates robustness of the adaptive fuzzy control DCS to environmental disturbances. Consequently, the proposed adaptive fuzzy control DCS is a model-free design that resolves the problem of depth-keeping and attitude stability controls of AUV with unknown hydrodynamic coefficients, rudder dynamics and time-varying external forces.

Automated Tuning of Nonlinear Kalman Filters for Optimal Trajectory Tracking Performance of AUVs

The performance of navigation algorithms significantly determines the trajectory tracking accuracy of the guidance, navigation, and control (GNC) system of an autonomous underwater vehicle (AUV). In closed-loop operation, the interaction among path planning, control, and navigation plays a crucial role in the tracking accuracy of the overall GNC system. A Doppler velocity log (DVL) is often used for AUVs to measure velocity over the ground, positively affecting the closed-loop tracking error. However, a DVL may not be installed in miniaturized AUVs due to limited space and energy. In this paper, a navigation filter for an underactuated miniature AUV (nanoAUV) is considered that is mainly based on acoustic localization using a novel highly-miniaturized ultra-short baseline (USBL) system and a depth pressure sensor. The nanoAUV is being developed for subglacial lake exploration. We compare two unscented Kalman filters (UKF) with different prediction models - the classical strapdown inertial navigation systems (SINS) model and a hydrodynamic motion model (HMM). To enable a fair comparison, filter parameters are auto-tuned with Bayesian optimization (BO) for open-and closed-loop performance, which is novel in AUV navigation. The results indicate that BO performs similarly to particle swarm optimization (PSO) regarding sample efficiency for the proposed problem. To quantify the GNC tracking performance, we use extensive Monte Carlo simulations. Results suggest that with BO-tuned navigation filter parameters, the median tracking error is reduced by up to 50% compared to default parametrization.

Survey on traditional and AI based estimation techniques for hydrodynamic coefficients of autonomous underwater vehicle

An accurately predicted dynamic model is essentially required to design a robust control system for an autonomous underwater vehicle (AUV) maneuvering in six degrees of freedom. The dynamic model consists of hydrodynamic derivatives which include inertial and damping coefficients. Traditionally, these coefficients can be estimated through Analytical and Semi-Empirical (ASE) methods, Computational Fluid Dynamics (CFD), and through experiments such as captive or free model testing. Additionally, System Identification (SI) estimators, e.g. extended Kalman filter, are also employed to predict the complete set of parameters. Recently, with the advent of Artificial Intelligence (AI) in almost every field of science, supervised machine learning algorithms such as Support Vector Machine (SVM) and neural network algorithms are also being applied to predict the coefficients with lesser computational cost and higher accuracy. Additionally, AI based parametric and non-parametric modeling of autonomous marine vehicles have also been discussed. Accordingly, the contributions of researchers and scientists, with respect to the evolution and application of these important techniques for marine vehicles, particularly torpedo-shaped AUVs, done over the past more than 75 years, have been thoroughly surveyed and sequentially consolidated in this article. At the end, based on the survey, merits and demerits of each technique over the others have been highlighted and published results have also been discussed to evaluate the effectiveness of these estimation techniques for autonomous underwater vehicles.

Robust Controller Design for AUV Subsystem Using µ Synthesis

The paper considers the problem of synthesizing the pitch control system of an autonomous underwater vehicle (AUV), considering the uncertainty of its parameters and underwater disturbances. The µ-synthesis using D-K iteration is applied to solve the problem. For the subsequent implementation of the controller in practice, a method for reducing its order based on the Hankel norm approximation is applied. The proposed approach is tested on the mathematical model of the MAYA AUV with the parameters deviating from the nominal values. The simulation result shows that the proposed robust control scheme effectively compensates for the parametric uncertainty and underwater disturbances.

Разработка и прототипирование распределенной системы управления геологоразведывательным необитаемым подводным аппаратом

Describes the process of developing a control system (CS) for an autonomous uninhabited underwater vehicle (AUUV) for shallow depths. A study of the prospects for the use of AUUV has been conducted. The work on the development and testing of the controller module for the control system is described. A laboratory installation has been developed to demonstrate the operation of the developed control system, which can be installed on an autonomous uninhabited underwater vehicle or used for educational purposes.

Autonomous Underwater Robot Fuzzy Motion Control System with Parametric Uncertainties

The paper describes the design of a fuzzy motion control system of an autonomous underwater vehicle. A mathematical model of the underwater vehicle is synthesized. A fuzzy regulator for controlling the depth of immersion autonomous underwater vehicle is designed. The quality of control for step control, harmonic control, as well as various types of exogenous disturbances, is investigated. The comparison of the functioning quality of the designed fuzzy controller with the proportional–derivative controller is made. It is shown that the designed fuzzy controller provides a higher quality of control compared to the proportional–derivative controller. The proposed fuzzy controller provides high-quality control of the plant under uncertainties.

Алгоритм обеспечения безопасности плавания автономного необитаемого подводного аппарата

Two safe navigation algorithms for autonomous underwater vehicles are described: algorithm for avoidance of point obstacles including all the moving underwater and surface objects, and limited size bottom objects, and algorithm for bypassing extended obstacles such as bottom elevations, rough lower ice edge, garbage patches. These algorithms are developed for a control system of a heavyweight autonomous underwater vehicle.

A Dispatcher for a Multi-Agent Control System of an Autonomous Underwater Vehicle: Structure, Algorithms, and Simulation Results

Algorithms for a dispatcher of a multi-agent control system for an autonomous underwater vehicle (AUV) are described. The algorithms are designed on a modular basis, which provides for the control of a wide range of tasks assigned to the AUV, and, in addition, makes the implementation of each algorithm simple.

Method of choice of architecture of a multi-agent control system of an autonomous underwater vehicle

Introduction: The continuous improvement of autonomous underwater vehicles, the complexity of their systems and the use of a hybrid energy supply system have led to the need of developing a control system using multi-agent technology. To date, a large number of styles of multi-agent architectures have been formed, mainly in the field of organizing the manufacture and developing software. It is important to choose the most suitable architecture style for a multi-agent control system of an autonomous underwater vehicle with a hybrid energy supply system, taking into account its features. Purpose: The development of a method for choosing the most suitable style of a multi-agent architecture among a variety of alternative options. Method: The developed method is based on comparative assessment of various architecture styles according to non-functional requirements. For this purpose, a target graph is specially developed, taking into account the features of the device to be designed. In addition, when generating the final result, the label distribution algorithm was used as the most suitable one for this problem. Results: The proposed method of choosing the architecture style includes the following components: developing indicators by which it is advisable to compare the alternative options; forming various styles of architectures most suitable for the device under construction; analyzing the positive and negative effects of the architecture style according to non-functional requirements; formalizing these influences in the form of qualitative or quantitative labels; obtaining the final grade by applying the label distribution algorithm. Practical relevance: The proposed method allows you to select the most appropriate architecture for a multi-agent control system of an autonomous underwater vehicle. The method can also be used for a wider range of ground-based and air-based robotic systems.

Approach to Reconfiguration of a Motion Control System for an Autonomous Underwater Vehicle

Reconfiguration of a motion control system (MCS) for an autonomous underwater vehicle (AUV) in case of failure of some of the controls or actuators that provide the vehicle propulsion and maneuvering is discussed. The features of actuators operating on different physical principles are analyzed. A nonlinear mathematical model of the vehicle motion is formed taking into account the features of the seawater medium due to higher viscosity. Nonlinearity does not allow traditional approaches to reconfiguration of aircraft motion control system to be used for the purposes described in this paper. The approach proposed for reconfiguration of the AUV MCS consists in the preliminary analysis of the conditions for using different kinds of actuators depending on the vehicle speed and maneuver. The choice of alternative efficient actuators is dictated by the need to compensate for the forces and moments generated by the failed equipment or the actuator to the maximum extent possible. The results of the AUV MCS reconfiguration are obtained for a failure of a bow rudders gear during the diving maneuver on the acceleration section of the path. Vertical thrusters are taken as backups capable of compensating for the forces and moments of the jammed bow rudders gear. The comparative quantitative estimates of the AUV MCS reconfiguration were obtained by mathematical simulation of the AUV diving maneuver. Further research is needed to extend the proposed approach to other AUV systems.

Robust tracking control of an underwater vehicle and manipulator system based on double closed-loop integral sliding mode

A nonlinear robust control method for the trajectory tracking of the underwater vehicle and manipulator system that operates in the presence of external current disturbances is proposed using double closed-loop integral sliding mode control. The designed controller uses a double closed-loop control structure to track the desired trajectory in the joint space of the underwater vehicle and manipulator system, and its inner and outer loop systems use integral sliding surface to enhance the robustness of the whole system. Then, the continuous switching mode based on hyperbolic tangent function is used instead of the traditional discontinuous switching mode to reduce the chattering of the control input of the underwater vehicle and manipulator system. In addition, the control method proposed in this article does not need to estimate the uncertainties of the underwater vehicle and manipulator system control system through online identification, but also can ensure the robustness of the underwater vehicle and manipulator system motion control in underwater environment. Therefore, it is easier to be implemented on the embedded platform of the underwater vehicle and manipulator system and applied to the actual marine operation tasks. At last, the stability of the control system is proved by the Lyapunov theory, and its effectiveness and feasibility are verified by the simulation experiments in MATLAB software.

Deriving a six-dimensional mathematical model of an unmanned underwater vehicle motion control system with interval parameters

The paper is dedicated to a problem of mathematical modeling of a motion control system for unmanned underwater vehicle. The proposed model considers interval parametric uncertainty of underwater vehicle itself and water environment, nonlinearity of control object and actuator of the system and interaction between its control channels. In order to derive the model several objectives were accomplished: a mathematical model of underwater vehicle motion in a viscous fluid in all six degrees of freedom was derived; mathematical model of separate thruster and whole propulsion and steering system was derived; both model were linearized with the help of interval linearization method and, finally, a structure of the whole motion control system was determined. The model is applicable for simulation modeling of underwater vehicle motion and for analysis and synthesis of motion control systems in condition of interval parametric uncertainty.

Диспетчер мультиагентной системы управления автономного необитаемого подводного аппарата: структура, алгоритмы, результаты моделирования

Algorithms for a dispatcher of a multi-agent control system for an autonomous underwater vehicle (AUV) are described. The algorithms are designed on a modular basis, which provides for the control of a wide range of tasks assigned to the AUV, and, in addition, makes the implementation of each algorithm simple.

Study of control system and flow analysis of an autonomous underwater vehicle

Study of control system and flow analysis of an autonomous underwater vehicle

Modularized Control System Design of Underwater Vehicle for Submarine Cable Inspection

Zhang, S.; Sun, L.; Fan, L.; Song, S., and Li, Z., 2018. Modularized control system design of underwater vehicle for submarine cable inspection. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 579–584. Coconut Creek (Florida), ISSN 0749-0208.At present, the control system of underwater vehicle does not take into account the influence of nonlinear hydrodynamic factors, but mainly collects the state information from the central controller and generates control signals. The control function of the system is concentrated, which leads to poor system flow resistance and slower speed. In view of this problem, combined with the actual application requirements of underwater vehicle for submarine cable inspection, in this paper, a method of control system design based on modular thinking is proposed. Considering the nonlinear hydrodynamic factors, the four degree of freedom motion modeling method of vehicle is presented. The hardware part of the vehicle control system is decomposed into a series of standard modules according to the function. By using the method of modularization, the control system design of underwater vehicle for submarine cable inspection is designed. Experimental results show that the system has better anti-flow capability and faster speed.

Control of Unmanned Underwater Vehicle as a Member of Vehicles Team Performing a Given Task

The article presents the control system of a single underwater vehicle which is a member of the underwater vehicles team. The application of the multi-agent system concept for modelling and controlling a team of homogeneous underwater vehicles is discussed. Issues relating to cooperation actions in the team of underwater vehicles are described and solved using the theory of games and vector quality index. The process of negotiations between the vehicles is modelled as a multiplayer cooperative game. Finally, the water region search tasks performed by a team of cooperating underwater vehicles are presented and discussed taking into account possible vehicle failures happening during task realization.

System for automatic soil sampling by AUV equipped with multilink manipulator

The development and research of the new synthesis method of the control system for an autonomous underwater vehicle (AUV) with a multilink manipulator is described in the paper. This system provides an automatic soil sampling and the taking of geological samples of a sea bottom surface. In automatic mode, the developed system defines the location of a bottom surface relative to the AUV by means of the onboard multibeam Doppler lag. During the vehicle immersion, the system evaluates the complexity of the bottom relief in the working area and makes decision on the suitability of the said relief for the trouble-free implementation of the specified manipulative tasks. Also, the proposed system realises the formation algorithm for spatial trajectories of the multilink underwater manipulator's working tool and defines the AUV spatial orientation and position at which the performing of manipulation operations occurs most efficiently and safely.

Synthesis of intelligent automatic control system of an autonomous underwater vehicle as a group agent

Synthesis of intelligent automatic control system of an autonomous underwater vehicle as a group agent

System for automatic soil sampling by AUV equipped with multilink manipulator

The development and research of the new synthesis method of the control system for an autonomous underwater vehicle (AUV) with a multilink manipulator is described in the paper. This system provides an automatic soil sampling and the taking of geological samples of a sea bottom surface. In automatic mode, the developed system defines the location of a bottom surface relative to the AUV by means of the onboard multibeam Doppler lag. During the vehicle immersion, the system evaluates the complexity of the bottom relief in the working area and makes decision on the suitability of the said relief for the trouble-free implementation of the specified manipulative tasks. Also, the proposed system realises the formation algorithm for spatial trajectories of the multilink underwater manipulator's working tool and defines the AUV spatial orientation and position at which the performing of manipulation operations occurs most efficiently and safely.