scholarly journals Design and Motion Simulation of an Underwater Glider in the Vertical Plane

2021 ◽  
Vol 11 (17) ◽  
pp. 8212
Author(s):  
Jiafeng Huang ◽  
Hyeung-Sik Choi ◽  
Dong-Wook Jung ◽  
Ji-Hyeong Lee ◽  
Myung-Jun Kim ◽  
...  
Keyword(s):  
Steady State ◽  
Buoyancy Force ◽  
Vertical Plane ◽  
Power Source ◽  
Motion Simulation ◽  
Underwater Glider ◽  
Simulation Performance ◽  
Underwater Gliders ◽  
Simulation Results ◽  
Sea Currents

Net buoyancy, as the main power source for the motion of an underwater glider, is affected by the pump or bladder that the glider adopts to change its buoyancy force in water. In this study, a new underwater glider that can dive to a depth of 400 m at a cruising speed of 2 knots, which is faster than conventional underwater gliders and is less affected by sea currents, is investigated. The UG resisting 400 m pressure on the buoyancy engine and achieving 2 knots’ speed was designed and constructed. For this UG, its steady-state attitude was studied according to the variance of the buoyancy center and the center of gravity with the buoyancy engine influenced by the displacement of the movable mass block. In motion simulation of the UG, the attitude of the UG under different displacement conditions was simulated in Simulink according to the displacements of the piston and the movable mass block. To validate the simulation performance, a UG was constructed and experiments were conducted. The simulation and experimental results were compared to show the reliability of the simulation results under limited conditions.

CFD Approach to Modelling Hydrodynamic Characteristics of Underwater Glider

2019 ◽  
Vol 2019 (4) ◽  
pp. 32-45
Author(s):  
Kamila Stryczniewicz ◽  
Przemysław Drężek
Keyword(s):  
Flow Behavior ◽  
Equations Of Motion ◽  
Vertical Plane ◽  
Dynamic Modelling ◽  
The Body ◽  
Hydrodynamic Characteristics ◽  
Motion Simulation ◽  
Underwater Glider ◽  
Lift And Drag ◽  
Equations Of Motions

Abstract Autonomous underwater gliders are buoyancy propelled vehicles. Their way of propulsion relies upon changing their buoyancy with internal pumping systems enabling them up and down motions, and their forward gliding motions are generated by hydrodynamic lift forces exerted on a pair of wings attached to a glider hull. In this study lift and drag characteristics of a glider were performed using Computational Fluid Dynamics (CFD) approach and results were compared with the literature. Flow behavior, lift and drag forces distribution at different angles of attack were studied for Reynolds numbers varying around 105 for NACA0012 wing configurations. The variable of the glider was the angle of attack, the velocity was constant. Flow velocity was 0.5 m/s and angle of the body varying from −8° to 8° in steps of 2°. Results from the CFD constituted the basis for the calculation the equations of motions of glider in the vertical plane. Therefore, vehicle motion simulation was achieved through numeric integration of the equations of motion. The equations of motions will be solved in the MatLab software. This work will contribute to dynamic modelling and three-dimensional motion simulation of a torpedo shaped underwater glider.

Dynamic Analysis of the Acoustic Velocity Profile Observation Underwater Glider

2013 ◽  
Vol 475-476 ◽  
pp. 50-54
Author(s):  
Li Juan Jia ◽  
Zhan Feng Qi ◽  
Sen Zhang ◽  
Yu Feng Qin ◽  
Jian Shi ◽  
...  
Keyword(s):  
Steady State ◽  
Large Scale ◽  
Acoustic Velocity ◽  
Design Parameters ◽  
Underwater Glider ◽  
Longitudinal Plane ◽  
Underwater Gliders ◽  
Long Duration ◽  
Fluent Software ◽  
Drag And Lift

Underwater gliders carried acoustic velocity meters can realize ocean profile observations of the acoustic velocity for long duration and large scale. This paper mainly studies the kinematics and hydrodynamics of the Slocum underwater glider carrying a acoustic velocity meter MINOSX with length 565mm and diameter 76mm. Thus, theory reference for optimal design parameters of the underwater glider is proposed. By establishing the kinematic equations and giving some related parameters, variations with time of the steady-state gliding velocity, pitch angle, gliding path and attack angle are simulated by using Matlab software; The simulation calculations of the hydro-drag and lift are completed by using Fluent software. Finally, this paper summarizes the dynamic characteristics in steady state of the underwater glider in longitudinal plane.

Dynamic Modeling and Motion Simulation of a Movable-Winged Underwater Glider

2012 ◽  
Vol 490-495 ◽  
pp. 1326-1331
Author(s):  
Bao Wei Song ◽  
Wen Long Tian ◽  
Zhao Yong Mao
Keyword(s):  
Dynamic Modeling ◽  
Autonomous Underwater Vehicles ◽  
Added Mass ◽  
Underwater Vehicles ◽  
Hydrodynamic Forces ◽  
Longitudinal Motion ◽  
Motion Simulation ◽  
Underwater Glider ◽  
Underwater Gliders ◽  
Motion Characteristics

Underwater gliders are a class of Autonomous Underwater Vehicles (AUVs) that offer many advantages over traditional AUVs. Previous research has mainly focused on underwater gliders with fixed wings. This paper studied a novel underwater glider whose wings can pitch independently about its installed shaft, called Movable-Winged Underwater Glider (MWUG). A 6-DOF model of dynamics for MWUG was developed based on Newton’s law and Euler’s equation, gravity, buoyancy, added mass forces and hydrodynamic forces considered. Longitudinal motion simulations were conducted to clarify the motion characteristics of MWUG. Results of the simulations indicated that compared to fix-winged gliders, MWUGs show a smaller glide angle and attack angle, higher glide speed and efficiency

Molecular Dynamics Study of Cohesionless Granular Materials: Size Segregation by Shaking

1993 ◽  
Vol 07 (09n10) ◽  
pp. 1865-1872 ◽  
Author(s):  
Toshiya OHTSUKI ◽  
Yoshikazu TAKEMOTO ◽  
Tatsuo HATA ◽  
Shigeki KAWAI ◽  
Akihisa HAYASHI
Keyword(s):  
Molecular Dynamics ◽  
Steady State ◽  
Specific Gravity ◽  
Pressure Gradient ◽  
Granular Materials ◽  
Buoyancy Force ◽  
Temporal Evolution ◽  
Particle Radius ◽  
Size Segregation ◽  
Increasing Function

The Molecular Dynamics technique is used to investigate size segregation by shaking in cohesionless granular materials. Temporal evolution of the height h of the tagged particle with different size and mass is measured for various values of the particle radius and specific gravity. It becomes evident that h approaches the steady state value h∞ independent of initial positions. There exists a threshold of the specific gravity of the particle. Below the threshold, h∞ is an increasing function of the particle size, whereas above it, h∞ decreases with increasing the particle radius. The relaxation time τ towards the steady state is calculated and its dependence on the particle radius and specific gravity is clarified. The pressure gradient of pure systems is also measured and turned out to be almost constant. This suggests that the buoyancy force due to the pressure gradient is not responsible to h∞.

scholarly journals Spatiotemporal Patterns Formed by a Discrete Nutrient-Phytoplankton Model with Time Delay

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Feifan Zhang ◽  
Wenjiao Zhou ◽  
Lei Yao ◽  
Xuanwen Wu ◽  
Huayong Zhang
Keyword(s):  
Steady State ◽  
Time Delay ◽  
Numerical Simulations ◽  
Functional Response ◽  
Bifurcation Analysis ◽  
Discrete Model ◽  
Continuous Model ◽  
Spatiotemporal Patterns ◽  
Homogeneous Steady State ◽  
Simulation Results

In this research, a continuous nutrient-phytoplankton model with time delay and Michaelis–Menten functional response is discretized to a spatiotemporal discrete model. Around the homogeneous steady state of the discrete model, Neimark–Sacker bifurcation and Turing bifurcation analysis are investigated. Based on the bifurcation analysis, numerical simulations are carried out on the formation of spatiotemporal patterns. Simulation results show that the diffusion of phytoplankton and nutrients can induce the formation of Turing-like patterns, while time delay can also induce the formation of cloud-like pattern by Neimark–Sacker bifurcation. Compared with the results generated by the continuous model, more types of patterns are obtained and are compared with real observed patterns.

scholarly journals Adaptive modulation based on steady-state mean square error for underwater acoustic communication

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Zhiyong Liu ◽  
Zhoumei Tan ◽  
Fan Bai
Keyword(s):  
Steady State ◽  
Mean Square Error ◽  
Adaptive Modulation ◽  
Blind Equalization ◽  
Training Sequence ◽  
Transmission Efficiency ◽  
Underwater Acoustic Communication ◽  
Mean Square ◽  
Modulation Mode ◽  
Simulation Results

AbstractTo improve the transmission efficiency and facilitate the realization of the scheme, an adaptive modulation (AM) scheme based on the steady-state mean square error (SMSE) of blind equalization is proposed. In this scheme, the blind equalization is adopted and no training sequence is required. The adaptive modulation is implemented based on the SMSE of blind equalization. The channel state information doesn’t need to be assumed to know. To better realize the adjustment of modulation mode, the polynomial fitting is used to revise the estimated SNR based on the SMSE. In addition, we also adopted the adjustable tap-length blind equalization detector to obtain the SMSE, which can adaptively adjust the tap-length according to the specific underwater channel profile, and thus achieve better SMSE performance. Simulation results validate the feasibility of the proposed approaches. Simulation results also show the advantages of the proposed scheme against existing counterparts.

scholarly journals Proton Exchange Membrane Fuel Cells Modeling Using Chaos Game Optimization Technique

2021 ◽  
Vol 13 (14) ◽  
pp. 7911
Author(s):  
Ibrahim Alsaidan ◽  
Mohamed A. M. Shaheen ◽  
Hany M. Hasanien ◽  
Muhannad Alaraj ◽  
Abrar S. Alnafisah
Keyword(s):  
Fuel Cell ◽  
Objective Function ◽  
Proton Exchange Membrane ◽  
Optimization Technique ◽  
Proton Exchange ◽  
Simulation Performance ◽  
Terminal Voltage ◽  
Chaos Game ◽  
Simulation Results ◽  
Exchange Membrane

For the precise simulation performance, the accuracy of fuel cell modeling is important. Therefore, this paper presents a developed optimization method called Chaos Game Optimization Algorithm (CGO). The developed method provides the ability to accurately model the proton exchange membrane fuel cell (PEMFC). The accuracy of the model is tested by comparing the simulation results with the practical measurements of several standard PEMFCs such as Ballard Mark V, AVISTA SR-12.5 kW, and 6 kW of the Nedstack PS6 stacks. The complexity of the studied problem stems from the nonlinearity of the PEMFC polarization curve that leads to a nonlinear optimization problem, which must be solved to determine the seven PEMFC design variables. The objective function is formulated mathematically as the total error squared between the laboratory measured terminal voltage of PEMFC and the estimated terminal voltage yields from the simulation results using the developed model. The CGO is used to find the best way to fulfill the preset requirements of the objective function. The results of the simulation are tested under different temperature and pressure conditions. Moreover, the results of the proposed CGO simulations are compared with alternative optimization methods showing higher accuracy.

Utilizing an Adaptive Controller (Azadi Controller) for Trajectory Planning of PUMA 560 Robot

2011 ◽  
Vol 403-408 ◽  
pp. 4880-4887
Author(s):  
Sassan Azadi
Keyword(s):  
Steady State ◽  
Trajectory Planning ◽  
Positive Feedback ◽  
Fuzzy Controller ◽  
Research Work ◽  
Adaptive Controller ◽  
The Novel ◽  
Transient Responses ◽  
Simulation Results ◽  
Good Substitute

This research work was devoted to present a novel adaptive controller which uses two negative stable feedbacks with a positive unstable positive feedback. The positive feedback causes the plant to do the break, therefore reaching the desired trajectory with tiny overshoots. However, the two other negative feedback gains controls the plant in two other sides of positive feedback, making the system to be stable, and controlling the steady-state, and transient responses. This controller was performed for PUMA-560 trajectory planning, and a comparison was made with a fuzzy controller. The fuzzy controller parameters were obtained according to the PSO technique. The simulation results shows that the novel adaptive controller, having just three parameters, can perform well, and can be a good substitute for many other controllers for complex systems such as robotic path planning.

A Robust Trajectory Tracking Control Scheme of Two-Link Flexible Manipulator

2011 ◽  
Vol 328-330 ◽  
pp. 2108-2112
Author(s):  
Jing Shuang Lu ◽  
Chun Mei Du ◽  
Rui Zhou ◽  
Na Li
Keyword(s):  
Trajectory Tracking ◽  
Tracking Control ◽  
Vertical Plane ◽  
Flexible Manipulator ◽  
System Model ◽  
Error Signal ◽  
Dynamics Model ◽  
Trajectory Tracking Control ◽  
Control Scheme ◽  
Simulation Results

A simple dynamics model is established based on the two-link flexible manipulator moving within the vertical plane, and a robust simple control scheme is put forward. The advantages of this scheme are simple and good robustness. Only the error signal is needed when designing the control scheme and the acquirement of control signal does not depend on the system model. The simulation results show that this method has a good robustness and stability.

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