Robust Hierarchical Hovering Control of Autonomous Underwater Vehicles via Variable Ballast System

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Anyuan Bi ◽  
Zhengping Feng ◽  
Chenlu He
Keyword(s):  
Control Strategy ◽  
Lower Layer ◽  
Autonomous Underwater Vehicles ◽  
Hierarchical Control ◽  
Underwater Vehicles ◽  
Uniform Asymptotic Stability ◽  
Modeling Errors ◽  
Mass Flowrate ◽  
Continuous Mass ◽  
Hovering Control

Abstract Hovering control of autonomous underwater vehicles (AUVs) via a variable ballast system (VBS) is challenging owing to the difficulty in precisely estimating related hydrodynamic coefficients and vertical disturbance. In this work, a hierarchical control strategy is proposed which comprises an upper layer—the proportional-integral-derivative (PID) type ballast water mass planner generating the desired ballast mass, and a lower layer—the continuous mass flowrate controller adjusting the actual ballast mass. The resulting flowrate algorithm endows the system with local uniform asymptotic stability and robustness to both modeling errors and vertical disturbance. Numerical results verify the feasibility and effectiveness of the proposed hierarchical hovering control strategy.

scholarly journals Advanced Autonomous Underwater Vehicles Attitude Control with L 1 Backstepping Adaptive Control Strategy

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4848
Author(s):  
Yuqian Liu ◽  
Jiaxing Che ◽  
Chengyu Cao
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Attitude Control ◽  
Autonomous Underwater Vehicles ◽  
Euler Angle ◽  
Underwater Vehicles ◽  
Linearization Method ◽  
Backstepping Control ◽  
Feedback Form ◽  
Adaptive Control Strategy

This paper presents a novel attitude control design, which combines L 1 adaptive control and backstepping control together, for Autonomous Underwater Vehicles (AUVs) in a highly dynamic and uncertain environment. The Euler angle representation is adopted in this paper to represent the attitude propagation. Kinematics and dynamics of the attitude are in the strict feedback form, which leads the backstepping control strategy serving as the baseline controller. Moreover, by bringing fast and robust adaptation into the backstepping control architecture, our controller is capable of dealing with time-varying uncertainties from modeling and external disturbances in dynamics. This attitude controller is proposed for coupled pitch-yaw channels. For inevitable roll excursions, a Lyapunov function-based optimum linearization method is presented to analyze the stability of the roll angle in the operation region. Theoretical analysis and simulation results are given to demonstrate the feasibility of the developed control strategy.

A Proposal for the Control of Teams of Autonomous Underwater Vehicles (AUVs) in Hierarchical and Peripheral Modes Using the Concept of Adaptive Autonomy

2006 ◽  
Author(s):  
Thomas Glotzbach ◽  
Ju¨rgen Wernstedt
Keyword(s):  
Autonomous Underwater Vehicles ◽  
Hierarchical Control ◽  
Underwater Vehicles ◽  
Control Approach ◽  
Further Development ◽  
Rational Behaviour

In this paper we discuss the further development of approaches for the control of vehicles with Adaptive Autonomy that have already been successfully used in single Autonomous Underwater Vehicles (AUVs) for cooperating teams of AUVs. A hierarchical control approach for a single AUV based on the Rational Behaviour Model (RBM) is presented. After the explanation of the concept of Adaptive Autonomy, this concept will be used to transfer the RBM- approach for single AUVs into another which can be used for the control of teams of AUVs. This new concept will contain a software task called ‘team instance’ that is responsible for the realisation of the cooperation between the vehicles. Finally, two concepts for the realisation of the ‘team instance’ are discussed and compared with each other, referring to possible real missions with teams of AUVs.

scholarly journals Design and Analysis of a Variable Buoyancy System for Efficient Hovering Control of Underwater Vehicles with State Feedback Controller

2020 ◽  
Vol 8 (4) ◽  
pp. 263 ◽  
Author(s):  
Brij Kishor Tiwari ◽  
Rajiv Sharma
Keyword(s):  
State Feedback ◽  
Autonomous Underwater Vehicles ◽  
Weather Conditions ◽  
Underwater Vehicles ◽  
Open Loop ◽  
Rate Of Change ◽  
Feedback Controller ◽  
State Feedback Controller ◽  
Adverse Weather ◽  
Hovering Control

The design process for Variable Buoyancy System (VBS) is not known in full, and existing approaches are not scalable. Furthermore, almost all the small size Autonomous Underwater Vehicles/Gliders (AUVs/G’s) use very low capacity of buoyancy change (in the range of few milliliters) and the large size AUVs require large buoyancy change. Especially for adverse weather conditions, emergency recovery or defense-related applications, higher rate of rising/sinking (heave velocity) is needed along with an ability to hover at certain depth of operation. Depth of UVs can be controlled either by changing the displaced volume or by changing the overall weight and, herein, our focus is on the later. This article presents the problem of design and analysis of VBS for efficient hovering control of underwater vehicles at desired depth using the state feedback controller. We formulate and analyze the design and analysis approach of VBS using the fundamental of mechanics, system dynamics integration and control theory. Buoyancy is controlled by changing the overall weight of the vehicle using the ballasting/de-ballasting of water in ballast tanks through the use of Positive Displacement Pump (PDP) for control in heave velocity and hovering depth. Furthermore, detailed mass metric analysis of scalable design of VBS for different buoyancy capacities is performed to analyze the overall performance of the VBS. Also, the performances of AUVs integrated with VBS of different buoyancy capacities are investigated in both the open loop and closed loop with the LQR state feedback controller. Hovering performance results are presented for three Design Examples (DEs) of AUVs with 2.8 m, 4.0 m and 5.0 m length and they are integrated with various buoyancy capacities at 9 kg/min rate of change of buoyancy. Results indicate that the AUVs achieve the desired depth with almost negligible steady state error and when they reach the desired hovering depth of 400 m the maximum pitch angle achieved of 16.5 degree for all the Des is observed. Maximum heave velocity achieved during sinking is 0.44 m/s and it reduces to zero when the vehicle reaches the desired depth of hovering. The presented computer simulation results indicate good performance and demonstrate that the designed VBS is effective and efficient in changing the buoyancy, controlling and maintaining the depth, controlling the heave velocity and can be used in rescue/attack operations of both the civil and defense UVs.

scholarly journals Proposal of an Automated Mission Manager for Cooperative Autonomous Underwater Vehicles

2020 ◽  
Vol 10 (3) ◽  
pp. 855 ◽  
Author(s):  
Néstor Lucas Martínez ◽  
José-Fernán Martínez-Ortega ◽  
Jesús Rodríguez-Molina ◽  
Zhaoyu Zhai
Keyword(s):  
Relational Database ◽  
Strong Correlation ◽  
Adaptive Systems ◽  
Autonomous Underwater Vehicles ◽  
Hierarchical Control ◽  
Underwater Vehicles ◽  
Level Manager ◽  
Control Pattern ◽  
Time Required ◽  
And Task

In recent years there has been an increasing interest in the use of autonomous underwater vehicles (AUVs) for ocean interventions. Typical operations imply the pre-loading of a pre-generated mission plan into the AUV before being launched. Once deployed, the AUV waits for a start command to begin the execution of the plan. An onboard mission manager is responsible for handling the events that may prevent the AUV from following the plan. This approach considers the management of the mission only at the vehicle level. However, the use of a mission-level manager in coordination with the onboard mission manager could improve the handling of exogenous events that cannot be handled fully at the vehicle level. Moreover, the use of vehicle virtualization by the mission-level manager can ease the use of older AUVs. In this paper, we propose a new mission-level manager to be run at a control station. The proposed mission manager, named Missions and Task Register and Reporter (MTRR), follows a decentralized hierarchical control pattern for self-adaptive systems, and provides a basic virtualization in regard to the AUV’s planning capabilities. The MTRR has been validated as part of the SWARMs European project. During the final trials we assessed its effectiveness and measured its performance. As a result, we have identified a strong correlation between the length of mission plan and the time required to start a mission ( ρ s = 0.79 ,   n = 45 ,   p 0.001 ). We have also identified a possible bottleneck when accessing the repositories for storing the information from the mission. Specifically, the average time for storing the received state vectors in the relational database represented only 18.50% of the average time required for doing so in the semantic repository.

A Neurodynamics Control Strategy for Real-Time Tracking Control of Autonomous Underwater Vehicles

2013 ◽  
Vol 67 (1) ◽  
pp. 113-127 ◽  
Author(s):  
Daqi Zhu ◽  
Xun Hua ◽  
Bing Sun
Keyword(s):  
Control Strategy ◽  
Tracking Control ◽  
Sliding Mode ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Sliding Mode Controller ◽  
Tracking Errors ◽  
Biologically Inspired ◽  
Adaptive Sliding Mode Controller ◽  
Real Time Tracking

A biologically inspired neurodynamics-based tracking controller of underactuated Autonomous Underwater Vehicles (AUV) is proposed in this paper. The proposed control strategy includes a velocity controller with biological neurons and an adaptive sliding mode controller. The biological neurons are embedded into the backstepping velocity controller to eliminate the sharp speed jumps commonly existing in vehicles due to tracking errors changing suddenly. The outputs of the velocity controller are used as the command inputs of the sliding mode controller, and the thruster control constraints problems that are commonly seen in the backstepping control of AUV are solved by the proposed controller. Simulation results show that the control strategy achieved success in smoothly tracking AUV position and velocity.

Finite-Time Formation Control for Autonomous Underwater Vehicles with Limited Speed and Communication Range

2014 ◽  
Vol 511-512 ◽  
pp. 909-912
Author(s):  
Jian Yuan ◽  
Feng Li Zhang ◽  
Zhong Hai Zhou
Keyword(s):  
Control Problem ◽  
Control Strategy ◽  
Finite Time ◽  
Cooperative Control ◽  
Formation Control ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Communication Range ◽  
Control Framework ◽  
Multi Robot

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.

scholarly journals Combined Depth Control Strategy for Low-Speed and Long-Range Autonomous Underwater Vehicles

2020 ◽  
Vol 8 (3) ◽  
pp. 181 ◽  
Author(s):  
Anyuan Bi ◽  
Fengye Zhao ◽  
Xiantao Zhang ◽  
Tong Ge
Keyword(s):  
Energy Saving ◽  
Long Range ◽  
Control Strategy ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Hierarchical Architecture ◽  
Low Speed ◽  
Depth Control ◽  
Type Variable ◽  
Inspection Tasks

Autonomous underwater vehicles (AUVs) are increasingly being applied to highly detailed survey and inspection tasks over large ocean regions. These vehicles are required to have underwater hovering and low-speed cruising capabilities, and energy-saving property to enable long-range missions. To this end, a combined depth control strategy is proposed in which an on-off type variable ballast system (VBS) is adopted for satisfactory hovering or fast descending/ascending without propulsion to reach the designated cruising depth, whereas the bow and stern fins act as the actuator to maintain the cruising depth for more energy saving. A hierarchical architecture-based VBS controller, which comprises a ballast water mass planner and an on-off mass flowrate controller, is developed to assure good hovering performance of the on-off type VBS. Both numerical studies and basin tests are conducted on a middle-sized AUV to verify the feasibility and validity of this depth control strategy.

Yaw stability control through independent driving torque control of mid and rear wheels of an articulated bus

2020 ◽  
Vol 234 (13) ◽  
pp. 2947-2960
Author(s):  
Wang Wenwei ◽  
Zhang Wei ◽  
Zhang Hanyu ◽  
Cao Wanke
Keyword(s):  
Control Strategy ◽  
Reference Model ◽  
Sliding Mode ◽  
Lower Layer ◽  
Hierarchical Control ◽  
Stability Control ◽  
Torque Control ◽  
Utilization Rate ◽  
Yaw Stability ◽  
Driving Torque

This paper describes a novel yaw stability control strategy for a four-wheel-independent-drive electric articulated bus with four motors at the middle and rear wheels. The proposed control strategy uses a hierarchical control architecture. In the upper layer, a 3 degree-of-freedom reference model is established to obtain the desired vehicle states and the desired yaw moments of the front and rear compartments are determined by means of sliding mode control, respectively. The lower layer distributes differential longitudinal forces according to the desired yaw moments based on quadratic programming theory. The tire utilization rate is used as the optimization goal considering the actual constraints. To verify performance, three test cases are designed on the dSPACE-ASM simulation platform. The test results show the proposed control strategy can improve the yaw stability and the trajectory following performance of the bus under different driving conditions.

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