The Nonlinear Suboptimal Diving Control of an Autonomous Underwater Vehicle (original) (raw)
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State-dependent Riccati equation-based robust dive plane control of AUV with control constraints
The paper treats the question of suboptimal dive plane control of autonomous underwater vehicles (AUVs) using the state-dependent Riccati equation (SDRE) technique. The SDRE method provides an effective mean of designing nonlinear control systems for minimum as well as nonminimum phase AUV models. It is assumed that the hydrodynamic parameters of the nonlinear vehicle model are imprecisely known, and in order to obtain a practical design, a hard constraint on control fin deflection is imposed. The problem of depth control is treated as a robust nonlinear output (depth) regulation problem with constant disturbance and reference exogenous signals. As such an internal model of first-order fed by the tracking error is constructed. A quadratic performance index is chosen for optimization and the algebraic Riccati equation is solved to obtain a suboptimal control law for the model with unconstrained input. For the design of model with fin angle constraints, a slack variable is introduced to transform the constrained control input problem into an unconstrained problem, and a suboptimal control law is designed for the augmented system using a modified performance index. Using the center manifold theorem, it is shown that in the closed-loop system, the system trajectories are regulated to a manifold (called output zeroing manifold) on which the depth tracking error is zero and the equilibrium state is asymptotically stable. Simulation results are presented which show that effective depth control is accomplished in spite of the uncertainties in the system parameters and control fin deflection constraints. r
Robust diving control of an AUV
Ocean Engineering, 2009
Mobile systems traveling through a complex environment present major difficulties in determining accurate dynamic models. Autonomous underwater vehicle motion in ocean conditions requires investigation of new control solutions that guarantee robustness against external parameter uncertainty. A diving-control design, based on Lyapunov theory and back-stepping techniques, is proposed and verified. Using adaptive and switching schemes, the control system is able to meet the required robustness. The results of the control system are theoretically proven and simulations are developed to demonstrate the performance of the solutions proposed.
Adaptive sliding mode control of autonomous underwater vehicles in the dive plane
Oceanic Engineering, IEEE …, 1990
The problem of controlling an Autonomous Underwater Vehicle (AUV) in a diving maneuver is addressed. The requirement for having a simple controller which performs satisfactorily in the presence of dynamical uncertainties calls for a design using the sliding mode approach, based on a dominant linear model and bounds on the nonlinear perturbations of the dynamics. Both nonadaptive and adaptive techniques are considered, leading to the design of robust controllers that can adjust to the changing dynamics and operating conditions. Also, the problem of using the observed state in the control design is addressed, leading to a sliding mode control system based on input-output signals in terms of dive-plane command and depth measurement. Numerical simulations using a full set of nonlinear equations of motion show the effectiveness of the proposed techniques.
Nonlinear H∞ Control Algorithms for AutonomousUnderwater Vehicle in Diving and Steering Planes
2018
During the last decade, significant research has been directed on designing autonomous underwater vehicles (AUVs) for several applications including surveillance of specific regions of a seafloor and underwater mine detection in defense applications, and scan-ning of pipelines and detection of leakages in oil/gas industries, etc. However, a number of issues arise in control of these AUVs such as control with autonomy, and commu-nication failure, etc., when underwater vehicles are deployed in underwater missions. Hence, there is a growing interest in developing control algorithms for underwater ve-hicles to address these issues. These mission control algorithms include appropriate controllers for executing path following, trajectory tracking and point stabilization motion plans. These algorithms can be executed by designing suitable controllers for the diving and steering planes of AUVs in face of parametric uncertainties that occur in AUV dynamics (e.g. hydrodynamic coefficients and...
Abstruct-A six degree of freedom model for the maneuvering of an underwater vehicle is used and a sliding mode autopilot is designed for the combined functions. In flight control a arise because the system to be controlled is highly nonlinear, coupled, and there is a good deal of parameter uncertainty and variation with operational conditions. The development of variable structure control in the form of sliding modes has been shown to provide robustness that is expected to be quite remarkable for AUV autopilot design. This paper shows that a multivariable sliding mode autopilot based on state feedback, designed assuming decoupled modeling, is quite s-ory for the combined speed, steering, and diving response of a slow speed AUV. The influence of speed, modeling nonlinearity, uncertainty, and disturbances, can be effectively compensated, even for complex maneuvering. Waypoint acquisition based on line of sight guidance is used to achieve path tracking.
Sliding mode control of an autonomous underwater vehicle
Proceedings. International Conference on Machine Learning and Cybernetics
In this study, an autonomous underwater vehicle (AUV) model with six degrees of freedom is presented to be shown having been linearized under several working conditions. Sliding Mode Control Law which is derived from linear theory is applied autonomous underwater vehicle for yaw steering plane. Simulation study is given to show that sliding mode controller designed assuming small states variation and decoupled plane cope with modeling non-linearity, uncertainty, disturbance effect.
Robust Diving and Composite Path Tracking Control of an Autonomous Underwater Vehicle
Autonomous Underwater Vehicles (AUVs) are becoming indispensable for the maritime industry and defense applications. The nonlinear, time-varying, and highly coupled dynamics of AUVs, along with the parametric uncertainties and unmodeled dynamics, make the design of efficient controllers a hard task. This article explores a robust control strategy that aims at providing better tracking accuracy by reducing the switching gain in order to reduce chattering and the control error bandwidth. The performance of the proposed controller is demonstrated through rigorous simulation on an experimentally validated AUV, and superior path tracking performance is noted against sliding mode and time delay control methodologies under various uncertain conditions.
Adaptive nonlinear control of an autonomous underwater vehicle
Transactions of the Institute of Measurement and Control, 2019
Autonomous underwater vehicles (AUVs) are highly nonlinear underactuated systems with uncertain dynamics and a challenging control problem. The main focus of this paper is to present a control law that shows desirable performance in the presence of modeling uncertainties. In this study, uncertainties are considered to be bounded and the AUV mathematical model is obtained in the presence of such uncertainties. Forces and torques applied to the AUV are also designed using a nonlinear dynamic controller. Appropriate adaptive rules are also presented to overcome system uncertainties and external disturbances. The adaptive nonlinear dynamic controller is designed based on upper bounds of system uncertainties and its stability is proven using the Lyapunov theory. In this article, the performance of the proposed control algorithm for tracking reference trajectories in an obstacle-rich environment is investigated. Therefore, the control algorithm is combined with potential fields for obstacle avoidance. Obtained results show the efficiency of the proposed controller.
Robust trajectory control of underwater vehicles
IEEE Journal of Oceanic Engineering, 1985
Underwater vehicles present difficult control-system design problems due to their nonlinear dynamics, uncertain models, and the presence of disturbances that are difficult to measure or estimate. In this paper, a recent extension of sliding mode control is shown to handle these problems effectively. The method deals directly with nonlinearities, is highly robust to imprecise models, explicitly accounts for the presence of high-frequency unmodeled dynamics, and produces designs that are easy to understand. Using a nonlinear vehicle simulation, the relationship between model uncertainty and performance is examined. The results show that adequate controllers can be designed using simple nonlinear models, but that performance improves as model uncertainty is decreased and the improvements can be predicted quantitatively. * JeanJacques E. Slotine (S'82-M'83) received the Ph.D. degree in estimation and control from the
Journal of Intelligent & Robotic Systems, 2018
Autonomous Underwater Vehicles (AUVs) are used in many applications such as the exploration of oceans, scientific and military missions, etc. Developing control schemes for AUVs is considered to be a very challenging task due to the complexity of the AUV model, the unmodeled dynamics, the uncertainties and the environmental disturbances. This paper develops a robust control scheme for the dynamic positioning and way-point tracking of underactuated autonomous underwater vehicles. In order to insure the robustness of the proposed controllers, the sliding mode control technique is adopted in the design process. Simulation results are given to validate the proposed controllers. Moreover, studies are presented to evaluate the robustness of the developed controllers with model uncertainties and under different types of disturbances including unknown currents.