Research of Trajectory Planning of a High-Altitude Long-Range Gliding Unmanned Underwater Vehicle

2014 ◽  
Vol 519-520 ◽  
pp. 1313-1320
Author(s):  
Guang Pan ◽  
Huan Huan Liu
Keyword(s):  
High Altitude ◽  
Long Range ◽  
Degrees Of Freedom ◽  
Underwater Vehicle ◽  
Water Entry ◽  
Dynamic Simulations ◽  
Six Degrees Of Freedom ◽  
Unmanned Underwater Vehicle ◽  
The One ◽  
Air Trajectory

The air trajectory planned studied of the high-altitude long-range gliding unmanned underwater vehicle (HALRG-UUV) based on segmented control strategy is proposed. The aim of this research is twofold. On the one hand, specifying an altitude penetration strategy at the end of the gliding stage was presented with the aim of improving the vehicle glide ratio and achieving penetration. On the other hand, a rocket deceleration strategy was applied to adjust the speed and attitude of the vehicle in order to meet the water entry requirement. Besides, six-degrees-of-freedom mathematical model of the HALRG-UUV was developed based on the Newton’s law. Dynamic simulations of the vehicle under various conditions were performed with the aid of the MATLAB/Simulink codes. The result shows that the vehicle has a glide ratio of 1/9 in the air trajectory and meets the water entry requirement above water. This study lays the foundation for the further research of maneuverability and water impact of the vehicle.

scholarly journals Long range predictability of atmospheric flows

2001 ◽  
Vol 8 (1/2) ◽  
pp. 55-67 ◽  
Author(s):  
R. Robert ◽  
C. Rosier
Keyword(s):  
Long Range ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Local Perturbation ◽  
Atmospheric Flow ◽  
Atmospheric Flows ◽  
2D Euler Equations ◽  
Large Scale Change ◽  
The One ◽  
Scale Motion

Abstract. In the light of recent advances in 2D turbulence, we investigate the long range predictability problem of atmospheric flows. Using 2D Euler equations, we show that the full nonlinearity acting on a large number of degrees of freedom can, paradoxically, improve the predictability of the large scale motion, giving a picture opposite to the one largely popularized by Lorenz: a small local perturbation of the atmosphere will progressively gain larger and larger scales by nonlinear interaction and will finally cause large scale change in the atmospheric flow.

Robust Autopilot Design for Unmanned Underwater Vehicle Based on H∞ Mixed Sensitivity

2012 ◽  
Vol 457-458 ◽  
pp. 764-772 ◽  
Author(s):  
Fang Rong Wang ◽  
Ru Wen Kan ◽  
Shu Nan Liu ◽  
Xu Bin Dong ◽  
Tao Shang ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
System Modeling ◽  
Nonlinear Problems ◽  
Underwater Vehicle ◽  
Unmanned Underwater Vehicle ◽  
Navigation Simulation ◽  
Underwater Navigation ◽  
Three Degrees Of Freedom

As the complexity of marine environment and the existence of uncertain factors along with Unmanned Underwater Vehicle (UUV) dynamics itself bringing many nonlinear problems, it is difficult to control the navigation in accordance with a predetermined trajectory. Based on the UUV dynamics analysis and system modeling, this paper decoupled its control system into three sub-control systems, designed robust autopilot using H∞ mixed sensitivity control algorithm to generate the low-order controller to achieve independent control of three degrees of freedom. Eventually, the underwater navigation simulation results show that the proposed method can provide better control performance and the method is feasible and high efficiency in actual applications.

Design of Robust Nonlinear Optimal Controller for Underwater Vehicle to Move in Depth Channel Using Gradient Descent Method with Systematic Step Selection

2014 ◽  
Vol 704 ◽  
pp. 320-324
Author(s):  
Marzieh Ahmadi ◽  
Abolfazl Halvaei Niasar ◽  
Alireza Faraji ◽  
Hassan Moghbeli
Keyword(s):  
Gradient Descent ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Parametric Uncertainty ◽  
Underwater Vehicle ◽  
Descent Method ◽  
Optimal Controller ◽  
Gradient Descent Method ◽  
Six Degrees Of Freedom ◽  
Step Selection

This paper proposes the design of a robust nonlinear optimal controller to move the underwater vehicle in the depth channel using gradient descent method. A nonlinear model with six degrees of freedom (6-DOF) has been extracted for the underwater vehicle. To selection of the model and design of controller, conventional assumptions used for other controllers have not been considered and the developed controller can be implemented via at least assumptions. In presented control method, systematic step selection for solving of the algorithm has increased the rate of convergence significantly. The performances of the proposed robust controller for moving in depth channel with considering of parametric uncertainty for the model have been confirmed via some simulations. The results show the desirable performance of developed controller.

scholarly journals Augmenting Maneuverability of UUVs with Cycloidal Propellers

2020 ◽  
Author(s):  
Manavendra Desai ◽  
Ruddhi Gokhale ◽  
Atanu Halder ◽  
Moble Benedict ◽  
Yin Lu Young
Keyword(s):  
Degrees Of Freedom ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Low Speed ◽  
Six Degrees Of Freedom ◽  
Hydrodynamic Motion ◽  
Screw Propeller ◽  
Heave Motion ◽  
Novel Concept ◽  
And Control

This paper investigates the novel concept of augmenting the maneuverability of underwater vehicles with cycloidal propellers. Cycloidal propellers have the potential of providing agile manoeuvring capabilities to an underwater vehicle such as enabling pure heave motion and spot turns. They will also enable the vehicle to surge in forward and backward directions with equal ease. Such manoeuvres are not possible with the more conventional screw propeller and control fin combinations. Moreover, cycloidal propellers can enable precise dynamic positioning in low speed applications like station-keeping, underwater surveying and maintenance, minesweeping and teaming activities. In this paper, manoeuvring capabilities of an underwater vehicle with conventional screw propeller and control fins only are compared with one augmented with cycloidal propellers. The cases considered include a turning circle manoeuvre, a low speed 180o turn and a low speed heave manoeuvre. A six degrees-of-freedom non-linear hydrodynamic motion prediction model was developed and validated. Simulation results demonstrated that compared to conventional propulsion systems, cycloidal propeller augmented underwater vehicles can be more swift and compact in low speed manoeuvres, making a case for further investigation into this concept.

An Autonomous Underwater Vehicle for Competition

2013 ◽  
Vol 380-384 ◽  
pp. 595-600
Author(s):  
Hai Tian ◽  
Bo Hu ◽  
Can Yu Liu ◽  
Guo Chao Xie ◽  
Hui Min Luo
Keyword(s):  
Control System ◽  
Hydrodynamic Model ◽  
Degrees Of Freedom ◽  
Autonomous Underwater Vehicle ◽  
Autonomous Underwater Vehicles ◽  
Vertical Motion ◽  
Underwater Vehicle ◽  
Step Response ◽  
Six Degrees Of Freedom ◽  
Simulink Simulation

The research of this paper was derived from the small autonomous underwater vehicle (AUV)Raider well performed in the 15th International Underwater Vehicle Competition (IAUVC),San Diego. In order to improve the performance of underwater vehicle, the control system of performance motion played an important role on autonomous underwater vehicles stable motion, and the whole control system of AUV is the main point. Firstly, based on the motion equations of six degrees of freedom, the paper simplified the dynamical model reasonably in allusion; Due to the speed of Raider to find the target was very low, this paper considered the speed was approximately zero and only considered the vertical motion. Therefore, this paper established the vertical hydrodynamic model of Raider, obtaining the transfer equation of vertical motion. Through the experiment and Matlab/Simulink simulation, this paper got the actual depth of the step response curve and simulation curve, and verified the validity of the vertical hydrodynamic model and the correlation coefficient.

GLOBAL OPTIMIZATION METHOD APPLIED TO THE KINEMATICS OF GAIT IN PREGNANT WOMEN

2016 ◽  
Vol 16 (06) ◽  
pp. 1650084 ◽  
Author(s):  
LILIANA AGUIAR ◽  
CARLOS ANDRADE ◽  
MARCO BRANCO ◽  
RITA SANTOS-ROCHA ◽  
FILOMENA VIEIRA ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Pregnant Women ◽  
Degrees Of Freedom ◽  
Morphological Changes ◽  
Optimization Method ◽  
Second Trimester ◽  
Hip Joints ◽  
Six Degrees Of Freedom ◽  
The One ◽  
Soft Tissue Artifact

Morphological changes are associated to pregnancy, such as weight gain and increased volume of the trunk. The soft tissue artifact can also increase with these characteristics and affect the real joint kinematics. The main objective of this study was to understand the effect of using three different constraining sets in the lower limb joints, in the amount of soft tissue artifact (STA) of pregnant women, in order to obtain the most appropriated joint set to be used in gait and in this population. The ankle, knee and hip joints were modeled respectively with the following characteristics: (1) Universal–revolute–spherical (URS), (2) spherical–revolute–spherical (SRS) and (3) spherical–spherical–spherical (SSS). The six degrees of freedom (6DOF) model was used as the basis for comparison and considered the one with the highest error associated to the STA. In pregnant women, the URS model seems to affect more the kinematic variables when compared with the 6DOF model. Assuming that the kinematic error associated with pregnant women is increased due to the STA, the URS model may be affecting more the angular kinematics of the knee joint. SSS model seems to be more appropriated to analyze gait in second trimester pregnant women.

Identification of a Variable Mass Underwater Vehicle Via Volterra Neural Network

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
T. Binazadeh ◽  
M. J. Yazdanpanah ◽  
M. H. Shafiei
Keyword(s):  
Neural Network ◽  
Vehicle Dynamics ◽  
Degrees Of Freedom ◽  
Variable Mass ◽  
Underwater Vehicle ◽  
Data Set ◽  
Six Degrees Of Freedom ◽  
Structure Selection ◽  
Recursive Parameter Estimation ◽  
Selection Of

The first step in designing a control system for a rigid body is to understand its dynamics. Underwater vehicle dynamics may be complex and difficult to model, mainly due to difficulties in observing and measuring actual underwater vehicle hydrodynamics response. This paper is concerned with structure selection of nonlinear polynomials in a Volterra polynomial basis function neural network and recursive parameter estimation of the selected model, in order to obtain a model of a variable mass underwater vehicle with six degrees of freedom using an input-output data set. The simulation results reveal the efficiency of the approach.

Effect of Wind Loads on the Performance of Free-Fall Lifeboats

2014 ◽  
Author(s):  
Thomas Sauder ◽  
Eloise Croonenborghs ◽  
Sebastien Fouques ◽  
Nabila Berchiche ◽  
Svein-Arne Reinholdtsen
Keyword(s):  
Numerical Simulations ◽  
Degrees Of Freedom ◽  
Free Fall ◽  
Offshore Structures ◽  
Water Entry ◽  
Forward Speed ◽  
Cfd Simulations ◽  
Six Degrees Of Freedom ◽  
Complete Set ◽  
Water Exit

The paper presents a model describing the launch of free-fall lifeboats from offshore structures in strong environmental wind. Six-degrees-of-freedom numerical simulations of the lifeboat launch are performed using the free-fall lifeboat simulator VARUNA with a complete set of wind coefficients for the lifeboat. Those wind coefficients are obtained by CFD simulations validated against wind tunnel tests. The lifeboat launch simulations are then verified against time-domain CFD simulations of the whole launch in air until water entry. It is shown by means of numerical simulations that wind-induced loads on the lifeboat have a strong influence on its kinematics until water entry, and subsequently on the acceleration loads experienced by the occupants, on the structural loads on the lifeboat, and on its forward speed after water exit. It is concluded that the effect of wind-induced loads on the lifeboat performances should in general be investigated when establishing the operational limits for a given offshore installation.

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