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.

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.

Design, Construction and Control of a Remotely Operated Vehicle (ROV)

2011 ◽  
Author(s):  
Alireza Marzbanrad ◽  
Jalil Sharafi ◽  
Mohammad Eghtesad ◽  
Reza Kamali
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Remotely Operated Vehicle ◽  
Six Degrees Of Freedom ◽  
Depth Sensors ◽  
Control Schemes ◽  
On Line ◽  
Operation Unit ◽  
And Control ◽  
Design Construction

This is report of design, construction and control of “Ariana-I”, an Underwater Remotely Operated Vehicle (ROV), built in Shiraz University Robotic Lab. This ROV is equipped with roll, pitch, heading, and depth sensors which provide sufficient feedback signals to give the system six degrees-of-freedom actuation. Although its center of gravity and center of buoyancy are positioned in such a way that Ariana-I ROV is self-stabilized, but the combinations of sensors and speed controlled drivers provide more stability of the system without the operator involvement. Video vision is provided for the system with Ethernet link to the operation unit. Control commands and sensor feedbacks are transferred on RS485 bus; video signal, water leakage alarm, and battery charging wires are provided on the same multi-core cable. While simple PI controllers would improve the pitch and roll stability of the system, various control schemes can be applied for heading to track different paths. The net weight of ROV out of water is about 130kg with frame dimensions of 130×100×65cm. Ariana-I ROV is designed such that it is possible to be equipped with different tools such as mechanical arms, thanks to microprocessor based control system provided with two directional high speed communication cables for on line vision and operation unit.

Model Tests for Safe-Return-to-Port of a Damaged Ship in Waves

2015 ◽  
Author(s):  
Jeonghwa Seo ◽  
Cristobal Santiago Bravo ◽  
Shin Hyung Rhee
Keyword(s):  
Degrees Of Freedom ◽  
Feedback System ◽  
Model Tests ◽  
Measurement Unit ◽  
Test Model ◽  
Motion Response ◽  
Six Degrees Of Freedom ◽  
Heading Angle ◽  
Wave Conditions ◽  
Damaged Ship

A series of tests using a course-keeping model ship with an autopilot system were carried out in a towing tank for research on Safe-Return-to-Port (SRTP). The autopilot system controls the rudder angle and propeller revolution rate by a feedback system. The variation of the heading angle of the test model with different control parameters was investigated first, to ensure that the test model had sufficient course-keeping maneuverability in severe wave conditions. The wave conditions and propeller revolution rate were selected based on SRTP regulations. Tests were conducted in wave conditions corresponding to sea states 4 to 6. The six-degrees-of-freedom motion response of the test model was measured by a wireless inertial measurement unit and gyro sensors to achieve fully wireless model tests. The advance speed and motion response in various wave conditions were measured and analyzed to investigate the effects of flooding behavior in a damaged condition and of waves on the propulsion and maneuvering performance of the damaged ship model.

Design and Testing Outline for a Free Running Model of a High Speed Craft

2020 ◽  
Author(s):  
Xinguo Wang ◽  
Jack Bonoli ◽  
Madeline Cohen ◽  
Mirjam Fürth
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Six Degrees Of Freedom ◽  
High Interest ◽  
Outdoor Environments ◽  
Free Running ◽  
Industry Professionals ◽  
Design And Testing ◽  
Very High ◽  
Testing Plan

Hydrodynamics of High Speed Craft is a topic of very high interest for recreational boaters and industry professionals alike. This project aims to be a first step toward conducting such experiments in exposed outdoor environments. This paper will outline a preliminary design and testing plan of a free running model of a high speed craft. The proposed free running model will be subjected to all six degrees of freedom, self propelled, autonomously controlled, and will be exposed to weather elements.

Theory and Method of Dynamic Modeling for Multilayer Vibration Isolation System

2000 ◽  
Author(s):  
Liao Dao-Xun ◽  
Lu Yong-Zhong ◽  
Huang Xiao-Cheng
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Rigid Bodies ◽  
Design Calculation ◽  
Isolation System ◽  
Dry Land ◽  
Vibration Isolation System ◽  
Six Degrees Of Freedom ◽  
Floating Raft

Abstract The multilayer vibration isolation system has been widely applied to isolate vibration in dynamic devices of ships, high-speed vehicles forging hammer and precise instruments. The paper is based on the coordinate transformation of space general motion for mass blocks (rigid bodies) and Lagrangian equation of multilayer vibration isolation system. It gives a strict mathematical derivation on the differential equation of the motion for the system with six degrees of freedom of relative motion between mass blocks (including base). The equations are different from the same kind of equations in the reference literatures. It can be used in the floating raft of ships in order to isolates vibration and decrease noise, also used in design calculation of the multilayer vibration isolation for dynamic machines and precise instruments on the dry land.

Maneuverability and Heading Control of a Quadruped Robot Utilizing Tail Dynamics

2017 ◽  
Author(s):  
Wael Saab ◽  
Pinhas Ben-Tzvi
Keyword(s):  
High Speed ◽  
Sufficient Conditions ◽  
Quadruped Robot ◽  
Robotic Systems ◽  
Improve Performance ◽  
Modeling And Analysis ◽  
System Sensitivity ◽  
Proposed Model ◽  
Heading Control ◽  
Heading Angle

This paper presents modeling and analysis of a quadruped robot that utilizes tail dynamics to control its heading angle. The tail is envisioned to assist locomotion as a means separate from its legs to generate forces and moments to improve performance in terms maneuverability. Tail motion is analyzed for both low and high-speed tail actuation to derive sufficient conditions to maintain equilibrium and formulate maneuverability relations that result in rotation and translation of the robotic system. Sensitivity analysis is presented to select optimal tail mass and length ratios to maximize the change of the heading angle. A heading controller is then proposed and simulated to achieve a desired heading angle utilizing tail dynamics. Results of this research will assist in the design, modeling, and analysis of robotic systems sharing similar topologies to the proposed model, such as mobile robots with wheeled, tracked, multi-legged, or articulated-body based locomotion with swinging extremities such as tails, torsos, and limbs.

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.

A Platform with Six Degrees of Freedom

1965 ◽  
Vol 180 (1) ◽  
pp. 371-386 ◽  
Author(s):  
D. Stewart
Keyword(s):  
Degrees Of Freedom ◽  
Six Degrees Of Freedom ◽  
Control Surfaces

This paper describes a mechanism which has six degrees of freedom, controlled in any combination by six motors, each having a ground abutment. It is considered that by its particular arrangement, this mechanism may form an elegant design for simulating flight conditions in the training of pilots. Unlike most simulators, it has no fixed axes relative to the ground, and therefore within the limits of amplitude of the design it can truly simulate the conditions of banking by carrying the simulation of control surfaces into the axes of the new attitude. Variations in control arrangements are described and their respective design merits considered. Other possible uses for this mechanism are mentioned, including automation of production.

An Experiment for the Study of Free-Flying Supercavitating Projectiles

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Peter J. K. Cameron ◽  
Peter H. Rogers ◽  
John W. Doane ◽  
David H. Gifford
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Measurement Techniques ◽  
Theoretical Models ◽  
Dynamics Simulation ◽  
Small Scale ◽  
Successful Operation ◽  
Six Degrees Of Freedom ◽  
Impact Location ◽  
Simulation Based

Applications and research utilizing supercavitation for high-speed underwater flight has motivated study of the phenomenon. In this work, a small scale laboratory experiment for studying supercavitating projectiles has been designed, built, and tested. Similar existing experimental work has been documented in literature but using large, elaborate facilities, or has been presented with ambiguous conclusions from test results. The projectiles were 63.5 mm in length and traveled at speeds on the order of 145 m/s. Measurement techniques are discussed and used to record projectile speed, supercavity dimensions, and target impact location. Experimental observations are compared with a six degrees-of-freedom dynamics simulation based on theoretical models presented in literature for predicting supercavity shape and hydrodynamic forces on the supercavitating projectile during flight. Experimental observations are discussed qualitatively, along with quantitative statistics of the measurements made. Successful operation of the experiment has been demonstrated and verified by agreement with theoretical models.

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