Papers by Keyword: Autonomous Underwater Vehicle (AUV)

Abstract: An autonomous underwater vehicle (AUV) should have the ability of adapting the complexity and unpredictability of the marine environment, which means that the technology of AUV’s fault diagnosis is very significant, especially the part of thrusters. In order to make it possible, one fault diagnosis strategy of AUV’s thrusters is proposed, which is based on the support vector machine (SVM). SVM has many unique advantages in solving small-sample, nonlinear and high dimensional problems. In this paper, different character signal is inputted SVM to train and test it. The simulation results show that the fault diagnosis of AUV’s thrusters based on offline SVM can classify the fault styles successfully, which proves its feasibility and effectiveness. This method offers a new way to solve the fault diagnosis of AUVs.

Abstract: This paper studies the implementation of an ADRC to deal with depth variations of AUV. The depth model of AUV is decoupled from the 6 DOF dynamics function at first. Then, the least square method is introduced to identify the nonlinear open-loop model of AUV offline, and a more accurate depth model that varies with the elevator angle is achieved. Finally, ADRC is applied to the improved depth model with the disturbance of inaccuracy elevator angle and the error of depth measurement. The result confirms that AUV depth model varies with the elevator angle, while the ADRC controller could reject the errors in the depth sensor and the disturbances of mechanical transmission of rudder and the nonlinear variations at different operating points. Comparing to the traditional PID controller, ADRC performs better respectively with these uncertainty. The contribution of the proposed controller would support to the future application to 3D motion control and path tracking of AUV in practice.

Abstract: Following the Model-Driven Architecture (MDA) approach, we have modeled and implemented a planar trajectory planning and tracking controller designed for Autonomous Underwater Vehicles or Autonomous Surface Vessels (AUVs/ASVs). Our approach covers steps such as the requirement, analysis, design and implementation to model and realize a controller for most standard AUV/ASV platforms. It also allows the designed elements to be customizable and re-usable in the development of new applications of AUV/ASV controllers. The paper describes step-by-step the development lifecycle of planar trajectory-tracking controller for AUVs/ASVs. Based on this approach, a horizontal trajectory-tracking controller of a miniature autonomous submerged vehicle is completely developed and successfully taken on trial trip.

Abstract: An autonomous under vehicle (AUV) should have the ability of self-saving and finishing the certain targets when faults occur, which means that an AUV must have the ability of fault-tolerant control. In order to make it possible, one AUV’s fault-tolerant control strategy is made, which is based on the active disturbance rejection control (ADRC). In this paper, the control method in normal and the one in fault are offered respectively. Besides that, one simulation compared with PID control is made. The simulation results show the AUV’s fault-tolerant control strategy based on ADRC can achieve the goal and has better control results to restrain the shock, overshoot and other phenomena caused by disturbance than the strategy based on PID.

Abstract: This paper addresses an adaptive modified square-root cubature Kalman filter for the navigation of autonomous underwater vehicles (AUVs). The standard square-root cubature Kalman filter (SCKF) implements the CKF using square-root filtering to reduce computational errors. It can be modified due to the nonlinear system with a linear measurement function. The modification leads to a decrease computational complexity. Sage-Husa noise statistics estimator is combined with the Modified SCKF to estimate the unknown and changing system process noise variance. The experimental results show that compared with the MSCKF and the EKF algorithm, the adaptive MSCKF show the best accuracy for a real system with unknown process noise variance.

Abstract: his paper deals with the cooperative navigation problem of multiple autonomous underwater vehicles (AUV). A novel method which does not depend on a beacon network like in long baseline positioning system is proposed. The principle of this approach is to realize the cooperative localization of AUVs by using relative range measurements between the leader and the follower vehicles by means of an extended Kalman filter. Simulation results that validate the effectiveness of this approach are presented.

Abstract: LBL(Long Baseline) positioning provides an important positioning and navigation method for AUV(Autonomous Underwater Vehicle)’s underwater task. Due to the complex underwater acoustic channel, and its poor anti-interference ability, a new feedback Kalman fiter algorithm was present in this paper. By combining travel time information with position information, the state of AUV was estimated accurately. By analyzing experimental results, it showed that the LBL positioning accuracy was improved, and the algorithm ensured AUV complete its autonomous navigation with high precision.

Abstract: A strategy is proposed for a control system with a linearized autonomous underwater vehicle (AUV) dynamic model. The proposed approach combines the particle swarm optimization (PSO) and proportional-integral-derivative (PID) controller to adjust the parameters of the linearized dynamic model. The linear and nonlinear model are both considered in our work. The proposed techniques is verified by using the simulation results to the model of AUV.

Abstract: Cooperative control of multiple autonomous underwater vehicles (AUVs) plays an important role on marine scientific investigation and marine development. The formation of multi-AUV can significantly enhance applications on the marine sampling, imaging, surveillance and communications. Compared to the formation control of multi-robot, the formation control of multi-AUV is particularly difficult, especially on controlling attitude and direction of AUV; what is more, the communication method among AUVs is acoustic. When communication distance increases, the communication qualities deteriorate quickly; this mainly makes time-delay, signal attenuation and distortion. Although formation control of multiple AUVs obtains a wide range of attention in recent years, the fruits on formation control problem are less than ones on land multi-robot problems. For example, Fiorelli conducted a collaborative and adaptive sampling research of multi-AUV at the Monterey Bay ^[; Yu and Ura carried out the cable-based modular fast-moving and obstacle-avoidance experiments, and presented an interconnected multi-AUV system with three-dimension sensors. On the aspect of formation control framework ^[2-, [ proposed a four-layer cooperative control strategy based on hierarchical structure; [ proposed a hierarchical control framework based on hybrid model. In addition, Yang converted a nonholonomic system to a chain one and designed a controller to implement a leader-follower formation for multiple AUVs in [. The formation control for multiple autonomous underwater vehicles is rather different than the control methods for other vehicles, because the formation control for AUVs is of its characteristics, such as the large-scale distribution in space. The finite-time consensus controller designing based on finite-time control and consensus problem has important theoretical and practical significance. The decentralized controller methods for the autonomous underwater vehicle are applied more and more, but they ignore the coupling relationship between them. Another method is that an AUV is modeling as an agent, but this method ignores attitude characteristics of AUVs (pitch, roll and yaw). In this paper, we consider the cooperative control problem in three dimensional spaces. Finite-time formation for Autonomous Underwater Vehicles (AUVs) with constraints on communication range is investigated. We proposed a two-layer finite-time consensus control law, to avoid leading to collapse on formation because of failure leader, all AUVs are arrayed in the same level and each AUV can obtain global formation information. Finally, the simulation results show the effectiveness of the control strategy.

Abstract: This paper addresses the observability problem of 2D Multiple Autonomous Underwater Vehicles (MAUVs) cooperative navigation system. We derive the conditions to keep the local weak observability of navigation system using the Lie derivatives, and characterize the unobservable trajectories of AUVs. We design a series of simulation experiments using the Extended Kalman Filter (EKF) to verify the theoretical results. Finally, the simulation results show that the good performance of navigation system can be presented if avoiding the unobservable trajectories of AUVs.