Nonlinear Robust Control Design for a Supercavitating Vehicle

2006 ◽  
Author(s):  
X. Mao ◽  
Q. Wang
Keyword(s):  
High Speed ◽  
Sliding Mode ◽  
Control Design ◽  
High Gain ◽  
System Stability ◽  
Control Surface ◽  
Supercavitating Vehicles ◽  
Supercavitating Vehicle ◽  
Final Design ◽  
Robust Control Design

Supercavitating vehicles can achieve very high speed but also pose technical challenges in maneuvering, system stability and control. Compared to a fully-wetted vehicle for which substantial lift is generated due to vortex shedding off the hull, the supercavitating vehicles are enveloped by gas surface thus the lift is provided by control surface deflections of cavitator and fins, as well as planing force between the vehicle and the cavity. The nonlinearity in the modeling of cavitator, fin, and in particular, the planing force make the control design more challenging. In this paper, a sliding-mode based controller is designed for the longitudinal dynamics of a supercavitating vehicle model. The stability and robustness of the final design are analyzed by the Lyapunov method and verified using simulation. A high-gain observer is also designed to estimate the vertical velocity of the supercavitating vehicle, which is not directly measurable, and then simulation results are presented for the (partial) output-feedback sliding-mode controller.

Heading control of a novel finless high-speed supercavitating vehicle with an internal oscillating pendulum

2020 ◽  
pp. 107754632094834
Author(s):  
Mojtaba Mirzaei ◽  
Hossein Taghvaei
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Sliding Mode ◽  
Six Degrees Of Freedom ◽  
Supercavitating Vehicles ◽  
Supercavitating Vehicle ◽  
High Speeds ◽  
Heading Control ◽  
Heading Angle ◽  
Control Surfaces

High-speed supercavitating vehicles are surrounded by a huge cavity of gas and only a small portion of the nose and the tail of the vehicle are in contact with the water which leads to a considerable reduction in skin friction drag and reaching very high speeds. High-speed supercavitating vehicles are usually controlled by the cavitator at the nose which controls the pitch and depth of the vehicle and the control surfaces or fins which control the roll and heading angle of the vehicle using the bank-to-turn maneuvering method. However, control surfaces have disadvantages such as the high drag force and ineffectiveness due to the supercavity. Therefore, the purpose of the present study is to eliminate the fins from high-speed supercavitating vehicles and propose a new bank-to-turn heading control of this novel finless high-speed supercavitating vehicle which is composed of the cavitator at the nose and an oscillating pendulum as the internal actuator. Sliding mode control as a robust method is used for the six-degrees-of-freedom model of this finless high-speed vehicle against exposed disturbances. Some design criteria for the design of the internal pendulum in this finless supercavitating vehicle are presented for the damping coefficient, pendulum mass, and radius.

A Benchmark Control Problem for Supercavitating Vehicles and an Initial Investigation of Solutions

2003 ◽  
Vol 9 (7) ◽  
pp. 791-804 ◽  
Author(s):  
John Dzielski ◽  
Andrew Kurdila
Keyword(s):  
High Speed ◽  
Linear Models ◽  
The Body ◽  
Control Surface ◽  
Force Model ◽  
Entire Body ◽  
Benchmark Problem ◽  
Supercavitating Vehicles ◽  
Forcing Function ◽  
Natural Cavitation

At very high speeds, underwater bodies develop cavitation bubbles at the trailing edges of sharp corners or from contours where adverse pressure gradients are sufficient to induce flow separation. Coupled with a properly designed cavitator at the nose of a vehicle, this natural cavitation can be augmented with gas to induce a cavity to cover nearly the entire body of the vehicle. The formation of the cavity results in a significant reduction in drag on the vehicle and these so-called high-speed supercavitating vehicles (HSSVs) naturally operate at speeds in excess of 75 m s-1. The first part of this paper presents a derivation of a benchmark problem for control of HSSVs. The benchmark problem focuses exclusively on the pitch-plane dynamics of the body which currently appear to present the most severe challenges. A vehicle model is parametrized in terms of generic parameters of body radius, body length, and body density relative to the surrounding fluid. The forebody shape is assumed to be a right cylindrical cone and the aft two-thirds is assumed to be cylindrical. This effectively parametrizes the inertia characteristics of the body. Assuming the cavitator is a flat plate, control surface lift curves are specified relative to the cavitator effectiveness. A force model for a planing afterbody is also presented. The resulting model is generally unstable whenever in contact with the cavity and stable otherwise, provided the fin effectiveness is large enough. If it is assumed that a cavity separation sensor is not available or that the entire weight of the body is not to be carried on control surfaces, limit cycle oscillations generally result. The weight of the body inevitably forces the vehicle into contact with the cavity and the unstable mode; the body effectively skips on the cavity wall. The general motion can be characterized by switching between two nominally linear models and an external constant forcing function. Because of the extremely short duration of the cavity contact, direct suppression of the oscillations and stable planing appear to present severe challenges to the actuator designer. These challenges are investigated in the second half of the paper, along with several approaches to the design of active control systems.

scholarly journals Robust block decomposition sliding mode control design

2002 ◽  
Vol 8 (4-5) ◽  
pp. 349-365 ◽  
Author(s):  
Alexander G. Loukianov
Keyword(s):  
Lyapunov Functions ◽  
Sliding Mode ◽  
Control Design ◽  
High Gain ◽  
Upper Bounds ◽  
Block Decomposition ◽  
Uncertain Nonlinear System ◽  
Recursive Procedure ◽  
Original Plant ◽  
Sliding Manifold

The paper examines the problem of sliding mode manifold design for uncertain nonlinear system with discontinuous control. The original plant first is decomposed such that the problem is divided into a number of simpler sub-problems. Then the block control recursive procedure is presented in which nonlinear sliding manifold is derived. Finally combined high gain and Lyapunov functions techniques are applied to establish hierarchy of the control gains and to estimate the upper bounds of the sliding mode equation solutions.

scholarly journals Robust Control of Underactuated Systems: Higher Order Integral Sliding Mode Approach

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Sami ud Din ◽  
Qudrat Khan ◽  
Fazal ur Rehman ◽  
Rini Akmeliawati
Keyword(s):  
Robust Control ◽  
Closed Loop ◽  
Sliding Mode ◽  
Integral Manifold ◽  
Control Design ◽  
Underactuated Systems ◽  
Control Laws ◽  
Beam System ◽  
Integral Manifolds ◽  
Robust Control Design

This paper presents a robust control design for the class of underactuated uncertain nonlinear systems. Either the nonlinear model of the underactuated systems is transformed into an input output form and then an integral manifold is devised for the control design purpose or an integral manifold is defined directly for the concerned class. Having defined the integral manifolds discontinuous control laws are designed which are capable of maintaining sliding mode from the very beginning. The closed loop stability of these systems is presented in an impressive way. The effectiveness and demand of the designed control laws are verified via the simulation and experimental results of ball and beam system.

Robust Control of Time-Delay Systems With Application to a Supercavitating Vehicle

2008 ◽  
Author(s):  
Xiaofeng Mao ◽  
Qian Wang
Keyword(s):  
Time Delay ◽  
Memory Effect ◽  
High Speed ◽  
Control Design ◽  
Stability Control ◽  
Delay Systems ◽  
Friction Drag ◽  
Surrounding Water ◽  
Supercavitating Vehicle ◽  
Modeling Uncertainties

Traditional underwater vehicles are limited in speed due to dramatic friction drag on the hull. A supercavitating vehicle exploits supercavitation to induce a gaseous cavity that contains most part of the vehicle and separates the vehicle hull from its surrounding water. Thus friction drag is substantially reduced. A supercavitating underwater vehicle can achieve very high speed, but also poses technical challenges in stability, control, and maneuvering due to various characteristics such as instability in open-loop dynamics, nonlinearity, cavity memory effect, etc. Among the existing literature on the control design for supercavitating vehicles, the cavity memory effect is often neglected to simplify system dynamics. In this paper, we take into account the cavity memory effect and model the supercavitating vehicle as a time-delay Quasi-Linear-Parameter-Varying system. Then a robust controller is designed to handle the switched, time-delay dependent behavior of the vehicle. The uncertainties considered in the presented control design include both parameter and planing force modeling uncertainties.

scholarly journals A Robust Impulsive Control Strategy of Supercavitating Vehicles in Changing Systems

2018 ◽  
Vol 8 (12) ◽  
pp. 2355
Author(s):  
Jonghoek Kim
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
Impulsive Control ◽  
Friction Drag ◽  
Pitch Change ◽  
Supercavitating Vehicles ◽  
Supercavitating Vehicle ◽  
Hydrodynamic Phenomenon ◽  
Impulsive Control Strategy ◽  
High Speed Vehicle

Supercavitation is a hydrodynamic phenomenon in which an underwater body is almost entirely inside the cavity wall. Since the density of the gas is much lower than that of water, skin friction drag can be reduced considerably. We develop controllers to control a supercavitating vehicle, which is a high-speed vehicle with a cavitator at its nose. We designed controllers based on impulsive inputs, which are used to change the pitch of the vehicle slightly. This slight pitch change is desirable, since a large pitch change can lead to instability of the vehicle due to large planing force. Moreover, our impulsive controllers are robust to disturbances. In practice, the vehicle consumed its fuel to move forward. This fuel consumption led to changing parameters of the vehicle, such as mass. To handle this changing system, we used fuzzy impulsive controllers. We ran simulations to verify the effectiveness of our controllers.

scholarly journals Adaptive robust control design to enhance smart grid power system stabilization using wind characteristics in Indonesia

2021 ◽  
Vol 12 (4) ◽  
pp. 2182
Author(s):  
Khamda Herbandono ◽  
Cuk Supriyadi Ali Nandar
Keyword(s):  
Robust Control ◽  
Smart Grid ◽  
Power System ◽  
High Reliability ◽  
Control Design ◽  
Adaptive Robust Control ◽  
System Stability ◽  
Identification System ◽  
Wind Characteristics ◽  
Robust Control Design

<span lang="EN-US">This paper is interested to study power system stability in smart grid power system using wind characteristic in south of Yogyakarta, Indonesia. To overcome the intermittent of wind characteristics, this paper presents adaptive robust control design to enhance power system stabilization. The online identification system is used in this research, which updated whenever the estimated model mismatch exceeds predetermined bounds. Then genetic algorithm (GA) is applied to re-tune parameters controller based on the estimated model. The structure of controller is proportional integral (PI) controller due to the most applicable in industry, simple structure, low cost and high reliability. Robustness of controller is guaranteed by taking system uncertainties into consideration. The performance of the proposed controller has been carried out in a hybrid wind-diesel power system in comparison with previous work controller. Simulation results confirm that damping effect of the proposed controllers are much better that of the conventional controllers against various operating.</span>

Sign in / Sign up

Export Citation Format

Share Document