Coordinated Target Tracking Strategy for Multiple Unmanned Underwater Vehicles With Time Delays

Unmanned underwater vehicles (UUVs) have become increasingly popular in recent years due to their use in various applications. The motivations for using UUVs include the exploration of difficult and dangerous underwater environments, military tasks in mine detection, intelligence gathering and surveillance, the inspection of offshore oil and gas infrastructure in the oil and gas industry, scientific research for studying marine life, and the search and rescue of missing persons or submerged airplanes or boats in underwater environments. UUVs offer many advantages in achieving the desired applications with increased safety, efficiency, and cost-effectiveness. However, there are also several challenges associated with their communication, navigation, power requirements, maintenance, and payload limitations. These types of vehicles are also prone to various disturbances caused by currents of the ocean, propulsion systems, and unmolded uncertainties. Practically, it is a challenging task to design a controller that will ensure optimal performance under these conditions. Therefore, the control system design is of prime importance in the overall development of UUVs. Also, the UUV controller receives input from different sensors, and the data from these sensors are used by the controller to perform different tasks. The control systems of UUVs should take into account all uncertainties and make them stable so that all sensors can perform optimally. This paper presents a complete review of different control system design algorithms for UUVs. The basic logic designs of several control system algorithms are also presented. A comparison is made based on reliability, robustness, precession, and the ability of the controller to handle the nonlinearity that is faced by UUVs during their missions. Simulation and experimental results are thoroughly studied to gain insight into each algorithm. The advantages and disadvantages of each algorithm are also presented, which will facilitate the selection of a suitable algorithm for the control system design of UUVs.

The formation of unmanned underwater vehicles (UUVs) has wide potential for applications in various marine activities. This paper studies the robust formation protocol design problem for multiple UUVs, whose dynamics are subject to nonlinearity, parametric uncertainties, and external disturbances. A robust distributed formation control scheme is proposed, which yields a control structure involving a position loop and an attitude loop to govern the translational motion and rotational motion, respectively. Theoretical analysis is given to show the robustness properties of the global closed-loop control system. Simulation results are provided to validate the effectiveness of the proposed formation control method.

Based on the application of important water area blockade, a new discontinuous guidance approach of an unmanned underwater vehicle (UUV) perpendicularly towards side of surface ship is proposed, and a hardware-in-the-loop simulation (HILS) system is established to demonstrate this guidance approach. This approach can be described as follows: a near-surface straight trajectory which is perpendicular to the predicted ship trajectory is figured out by detection device of UUV which is hidden underwater after the ship target is located. When the horizontal distance between UUV and the ship target meets start-up condition, UUV climbs to a certain depth near the sea surface and then runs along the horizontal straight trajectory. During its motion, UUV periodically measures the sight line between the UUV and ship target. In order to restrain the horizontal rotation of the sight line, a discontinuous guidance approach is proposed by using the deviation of the two adjacent sight lines and the distance between the UUV and the ship target to adjust the UUV’s velocity. After certain times of adjustment of the UUV’s velocity, UUV impacts the side of ship target perpendicularly with required accuracy. This near-surface discontinuous guidance approach makes it possible for UUV to be guided through optical or radar detection. Further discussions are made including miss distance caused by this proposed guidance approach, cycle of sight line detection, UUV’s non-attack zone and UUV start-up condition. Finally, a set of HILS is carried out to demonstrate the performance of the discontinuous guidance approach on an experimentally validated UUV model.

Multiple Unmanned Underwater Vehicles(UUVs) can be widely used in marine science expedition, ocean development and ocean engineering. And in the Unmanned Underwater Vehicles cluster, the Multi-Robot Task Allocation with communication range limitations is an important issue. In the past, many works were researched based on perfectly good communication conditions. However, in actual situations, especially underwater environments, communication range between robots is often limited. So in this paper, in order to ensure the communication range between the UUVs as much as possible, based on the Hoplites framework, we first design the communication keep revenue so that the UUVs not only perform the task but also try to ensure the communication range between the UUVs. Second, when there are individual tasks that are particularly far away from all other tasks, a communication relay node needs to be added between the UUV and other UUVs. We regard the communication relay node as a task, which is realized by using the active coordination mechanism of the Hoplites framework. Through the simulation environment of multiple UUVs, we conduct experiments and analysis of the algorithm, and the results show tangible performance gain of our methods over previous methods.

Unmanned underwater vehicles (UUVs) typically operate in uncertain and changing environments. Globally convergent Lyapunov-based parameter-adaptive controllers for six-degree-of-freedom position and attitude trajectory-tracking control of astable UUVs have been successfully derived and applied. We propose an efficient adaptive-control scheme for UUVs based on existing parameter-adaptation schemes popular in the robotics literature. Specifically, we customize bounded-gain-forgetting composite adaptation, which utilizes information about both the tracking and model-prediction errors to yield faster parameter convergence than the traditional tracking-error-based (TEB) adaptation. Hence, better transient behavior of tracking errors is achieved by using fewer control efforts in most cases. We show the effectiveness of applying the suggested adaptation scheme on UUVs through simulation.

In this paper, in terms of the system structure of a single unmanned underwater vehicle (UUV), combined with the autonomous and coordinated requirements of UUVs in the formation, the multi-UUVs formation distributed control system is constructed, based on coordinated layer. Using the UUV non-linear coupling model as the control object, the multi-UUVs formation coordinated control system is constructed, based on precise feedback linearization. Aiming at the limitation of hydro-acoustics communication bandwidth and the delay of communication system, a UUV formation coordination control method is proposed, based on double independent communication topologies. Under the conditions of double-layer communication topology, each UUV receives the position and velocity status information of other members at the same time. And using the consistency theory verifies the stability of the multi-UUVs formation. Lastly, the stability of multi-UUVs formation in traditional topology and double-layer topology is simulated and verified, respectively.

Researchers are currently conducting several studies in the field of navigation systems and sensors. Even in the past, there was a lot of research regarding the field of velocity sensors for unmanned underwater vehicles (UUVs). UUVs have various services and significance in the military, scientific research, and many commercial applications due to their autonomy mechanism. So, it’s very crucial for the proper maintenance of the navigation system. Reliable navigation of unmanned underwater vehicles depends on the quality of their state determination. There are so many navigation systems available, like position determination, depth information, etc. Among them, velocity determination is now one of the most important navigational criteria for UUVs. The key source of navigational aids for different deep-sea research projects is water currents. These days, many different sensors are available to monitor the UUV’s velocity. In recent times, there have been five primary types of sensors utilized for UUV velocity forecasts. These include Doppler Velocity Logger sensors, paddlewheel sensors, optical sensors, electromagnetic sensors, and ultrasonic sensors. The most popular sensing sensor for estimating velocity at the moment is the Doppler Velocity Logger (DVL) sensor. DVL sensor is the most fully developed sensor for UUVs in recent years. In this work, we offer an overview of the field of navigation systems and sensors (especially velocity) developed for UUVs with respect to their use with tidal current sensing in the UUV setting, including their history, evolution, current research initiatives, and anticipated future.

Finite-time sideslip observer-based synchronized path-following control of multiple unmanned underwater vehicles

This manuscript considers a team of Unmanned Underwater Vehicles (UUVs) such that each UUV measures the arrival time of sound signal generated from the evader. The purpose of the UUV team is to intercept the underwater evader based on the arrival time measurements. We present both the motion control for the UUV team and the algorithm to estimate the evader position in real time. In this manuscript, the UUVs chase the evader while preserving a 3D spherical formation. Moreover, the formation size is controlled adaptively to assure the convergence of the evader estimation. Our tracking approach doesn't require global localization of every UUV. The proposed approach only requires that the central UUV measures the relative position of any other UUV using proximity sensors. Simulations are utilized to verify the effectiveness of the proposed method.

Many small Unmanned Underwater Vehicles (UUVs) currently utilize inexpensive, low resolution sonars that are either mechanically or electronically steered as their main sensors. These sonars do not provide high quality images and are quite dissimilar from the broad area search sonars that will most likely be the source of the localization data given to the UUV in a reacquisition scenario. Therefore, the acoustic data returned by the UUV in its attempt to reacquire the target will look quite different from the original wide area image. The problem then becomes how to determine that the UUV is looking at the same object. Our approach is to exploit the maneuverability of the UUV and currently unused information in the echoes returned from these Commercial-Off-The-Shelf (COTS) sonars in order to classify a presumptive target as an object of interest. The approach hinges on the ability of the UUV to maneuver around the target in order to insonify the target at different frequencies of insonification, ranges, and aspects. We show how this approach would allow the UUV to extract a feature set derived from the inversion of simple physics-based models. These models predict echo time-of-arrival and inversion of these models using the echo data allows effective classification based on estimated surface and bulk material properties. We have simulated UUV maneuvers by positioning targets at different ranges and aspects to the sonar and have then interrogated the target at different frequencies. The properties that have been extracted include longitudinal, and shear speeds of the bulk, as well as longitudinal speed, Rayleigh speed, and density of the surface. The material properties we have extracted using this approach match the tabulated material values within 8%. We also show that only a few material properties are required to effectively segregate many classes of materials.

UUV two-phase formation and priority avoidance control considering steering amplitude limitation

In order to solve the problem that the traditional navigation algorithm is unavailable for Unmanned Underwater Vehicles (UUVs) navigation in the polar region, a transversal navigation algorithm for polar UUV navigation is proposed in this paper. Traditional latitude and longitude is redefined in the transversal navigation algorithm to overcome the problems caused by the rapid convergence of the meridians in high latitude areas. Based on the transversal latitude and longitude coordinate system, the relevant frames are also redefined. According to the frames, the error equations of polar UUV navigation are established. Then, the states and observation equations are proposed. Considering the characters of UUV, OCTANS and Doppler velocity log (DVL) are chosen to assist the polar UUV navigation. Transversal Strapdown Inertial Navigation System (SINS), OCTANS and DVL form the integrated navigation algorithm. An adaptive Kalman filter (AKF) is introduced to realize the data fusion. Compared with the traditional SINS, the performance of the transversal navigation algorithm proposed in this paper is verified. The simulation results demonstrate that the proposed transversal navigation algorithm is suitable for polar UUV navigation.

In modern marine warfare, unmanned underwater vehicles (UUVs) have fast and efficient attack capabilities. However, existing research on UUV attack strategies is relatively limited, often ignoring the requirement for the effective allocation of different strategic value areas, which restricts its performance in the marine combat environment. To this end, this paper proposes an innovative UUV task allocation and saturation attack strategy. The strategy first divides the area according to the distribution density of enemy UUVs, and then reasonably allocates tasks according to the enemy’s regional value and the attack capability of our UUVs. Our UUVs then sail to the enemy area and are evenly distributed in the encirclement to ensure accurate saturation attacks. In the task allocation link, the grey wolf optimizer is improved by introducing Logistic chaos mapping and differential evolution mechanism, which improves the search efficiency and allocation accuracy. At the same time, the combination of the optimal matching algorithm and Bezier curve dynamic path control ensures the accuracy and flexibility of a coordinated attack. The simulation experimental results show that the strategy shows high attack efficiency and practicality in marine combat scenarios, providing an effective solution for UUV attack tasks in complex marine environments.

This paper describes a study on the dynamic modeling and the motion simulation of an unmanned ocean platform to overcome the limitations of existing unmanned ocean platforms for ocean exploration. The proposed unmanned ocean vehicle combines an unmanned surface vehicle and unmanned underwater vehicle with an underwater cable. This platform is connected by underwater cable, and the forces generated in each platform can influence each other’s dynamic motion. Therefore, before developing and operating an unmanned ocean platform, it is necessary to derive a dynamic equation and analyze dynamic behavior using it. In this paper, Newton’s second law and lumped-mass method are used to derive the equations of motion of unmanned surface vehicle, unmanned underwater vehicle, and underwater cable. As the underwater cable among the components of the unmanned ocean platform is expected to affect the motion of unmanned surface vehicle and unmanned underwater vehicle, the similarity of modeling is described by comparing with the cable modeling results and the experimental data. Finally, we constructed a dynamic simulator using Matlab and Simulink, and analyzed the dynamic behavior of the unmanned ocean platform through open-loop simulation.

Trajectory tracking control refers to the movement of an unmanned underwater vehicle (UUV) along a desired trajectory, which is a critical technology for the underwater tasks of UUVs. However, in actual scenarios, the reaction torque of propellers induces roll motion in UUVs, and the communication resource and computational resource of UUVs are limited, which affects the trajectory tracking performance of UUVs severely. Hence, this paper introduces an event triggering mechanism to design the double-loop integrated sliding mode control (EDLISMC), which is used for the trajectory tracking control of UUVs. This method designs the kinematic model and dynamic model of 6 degree of freedom (DoF) UUVs under the influence of reaction torque. Then, this method derives the dual loop integral sliding mode controller and designs the event triggering mechanism based on the relative threshold to reduce unnecessary control signals and improve the control efficiency of UUVs. In addition, this method uses a positive lower bound method to verify that the proposed event triggering mechanism does not have Zeno behavior and adopts the Lyapunov theorem to analyze the stability of EDLISMC. Finally, this paper conducts simulations on the simulink component of MATLAB. The relevant simulation proves that the proposed method can complete the trajectory tracking control of UUVs under the influence of reaction torque and it is superior to other methods in terms of resource consumption.