Investigation on the rudder force of a ship in large drifting conditions with the MMG model

2021 ◽  
Author(s):  
H. Yasukawa ◽  
T. Ishikawa ◽  
Y. Yoshimura
Keyword(s):  
Mmg Model

Modeling and Simulation of Ship Motion for Dynamic Positioning Vessel

2014 ◽  
Vol 919-921 ◽  
pp. 2127-2130
Author(s):  
Pei Wen Yu ◽  
Hui Chen
Keyword(s):  
Modeling And Simulation ◽  
Wind Wave ◽  
Ship Motion ◽  
Dynamic Positioning ◽  
Positioning System ◽  
Dynamic Positioning System ◽  
Oil Supply ◽  
Mmg Model ◽  
Simulation Results

The paper presents a method to build MMG model of ship motion for a oil supply vessel (OSV) with dynamic positioning system. It is assumed that the ship motion exposed to environment disturbances like wind, wave & currents, The simulation results show that the model of the vessel and environment disturbances are suitable, and the method is practicable .

scholarly journals Ship Maneuvering Performance Prediction Based on MMG Model

2018 ◽  
Vol 452 ◽  
pp. 042046 ◽  
Author(s):  
Yu Xia ◽  
Shutao Zheng ◽  
Yu Yang ◽  
Zhiyong Qu
Keyword(s):  
Performance Prediction ◽  
Ship Maneuvering ◽  
Mmg Model

Maneuvering Behavior of Ships in Irregular Waves

2013 ◽  
Author(s):  
Renato Skejic ◽  
Odd M. Faltinsen
Keyword(s):  
Deep Water ◽  
Cross Flow ◽  
Irregular Waves ◽  
Scale Model ◽  
Wave Loads ◽  
Ship Maneuvering ◽  
Slender Body Theory ◽  
Statistical Point ◽  
Irregular Wave ◽  
Mmg Model

Ship maneuvering in waves is analyzed by using a unified seakeeping and maneuvering two-time scale model in irregular sea that has been applied by Skejic and Faltinsen [1] for regular waves. The irregular wave effects are accounted for by Newman’s [2] approximation of the slow-drift 2nd order wave loads valid for deep water (Faltinsen [3], Pinkster [29]). The modular type maneuvering model (MMG model) based on Söding’s [4] nonlinear slender-body theory is used for the maneuvering analysis. Forces and moments due to rudder, propeller, and viscous cross-flow are accounted for as presented by Skejic and Faltinsen [1] and Yasukawa [5, 6]. In particular, the behavior of the propulsive coefficients (the thrust deduction and wake fraction) in waves (Faltinsen et al. [7], Faltinsen and Minsaas [8]) are discussed from the perspective of ship maneuvering characteristics in both regular and irregular wave environments. The unified model of seakeeping and maneuvering for deep-water irregular waves is validated for the ‘S7-175’ (‘SR 108’) container ship in calm water and regular deep-water wave scenarios by comparison with experimental results by Yasukawa [5, 6]. The maneuvering model is applied to a ‘MARINER’ ship performing turning maneuver in irregular waves. The obtained results of the ships main maneuvering parameters are discussed from a statistical point of view.

CFD-Based Calculation of Regular Transverse Wave Force in the Maneuvering Mathematical Modeling Group (MMG) Model

2013 ◽  
Vol 380-384 ◽  
pp. 1716-1720 ◽  
Author(s):  
Lin Jia Yang ◽  
Yi Han Tao
Keyword(s):  
Mathematical Modeling ◽  
Transverse Wave ◽  
Calculated Data ◽  
Wave Force ◽  
Force Model ◽  
Slender Body Theory ◽  
Disturbing Force ◽  
Regression Formula ◽  
Modeling Group ◽  
Mmg Model

The accuracy of mathematical model has a great effect on the prediction of ships maneuverability. Wave disturbing force is an important element of the Maneuvering Mathematical Modeling Group (MMG). Building regression formula of wave disturbing force acting on the ship hull can not only increase ship mathematical models accuracy but also help to predict ships maneuverability. The wave force can be calculated by the Computational Fluid Dynamics (CFD) method, which is more accurate and economical. The 3D model of M/V YUKUN was established and the cut-cell mesh was made. A numerical wave tank was developed in this work, based on the FLUENT software. The calculation results were obtained with different height, length, and period of waves. After analyzing the calculated data obtained by the CFD simulation, a regression formula was built about the above parameters. Finally, after comparing the regression formula and tradition wave force model based on the slender body theory, it can be concluded that the regular transverse wave force regression formula of the YUKUN is valid and better to make simulation for the prediction on ships maneuverability.

scholarly journals NUMERICAL SIMULATION OF SHIP NAVIGATION IN ROUGH SEAS BASED ON ECMWF DATA

Brodogradnja ◽  
2021 ◽  
Vol 72 (1) ◽  
pp. 19-58
Author(s):  
Patil Prasad Vinayak ◽  
◽  
Chelladurai Sree Krishna Prabu ◽  
Nagarajan Vishwanath ◽  
Sha Om Prakash
Keyword(s):  
Fuel Consumption ◽  
Service Providers ◽  
Recent Change ◽  
Statistical Characteristics ◽  
Weather Data ◽  
Weather Pattern ◽  
Weather Routing ◽  
Mmg Model ◽  
Ship Navigation ◽  
Ocean Environment

Recently, several changes have been observed in the Earth’s environment. This is also applicable to the ocean environment. The concept of weather routing has been applied for ship navigation for a long time. Many service providers offer weather routing service with the availability of high-quality satellite data. Unfortunately, not much information is available in the public domain as to how much the recent change in the weather pattern has affected ship navigation. The purpose of this paper is to fill this information gap. We investigate the influence of recent changes in the ocean environment on ship navigation. Weather data from ECMWF, namely ERA-Interim, is used for this purpose. The ECMWF data for the last 27 years is analysed. We compute the statistical characteristics of this data for the first 10 years, last 10 years, and 27 years. The statistical characteristics of the data are determined based on “summer” and “winter” zones as defined by international maritime regulations. Six different worldwide commercial ship routes are selected covering all the ocean regions. Navigation on great ellipse with waypoint is considered. MMG type ship manoeuvring model for 3 different ship types (DTMB 5415, PCC, VLCC) is used. The added resistance due to wave, wind and the effort of keeping the ship on the desired course using autopilot in the rough ocean environment is included in the MMG model. The fuel consumption and the duration of each one of the voyage are computed. Based on the analysis and simulation results it is shown that: (i) The mean wave height, wave period, and wind speed has increased in some ocean zones and decreased in other ocean zones. If any change has occurred, it is uniform for both seasons (summer and winter). (ii) In which ocean regions there is a perceptible change in fuel consumption, average ship speed and voyage time due to the changes in the weather pattern. (iii) The changing weather pattern in different ocean zones affects each ship type differently.

Numerical Evaluation of Ship Turning Performance in Regular and Irregular Waves

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Min-Guk Seo ◽  
Bo Woo Nam ◽  
Yeon-Gyu Kim
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Irregular Waves ◽  
Time Signal ◽  
Group Model ◽  
Frequency Wave ◽  
Wave Condition ◽  
Wave Drift ◽  
Mmg Model ◽  
Drift Force

Abstract In this study, ship's maneuvering performance in waves is evaluated using numerical computation. To this end, three degrees-of-freedom (3DOF) planar motions are considered, and modular-type maneuvering model (maneuvering modeling group model (MMG model)) is applied. As external force of the equation of motion, hull force, propulsion force, rudder force, and wave drift force are adopted. In order to calculate wave drift force, seakeeping program which is based on a higher-order Rankine panel method is used by considering wave frequency, wave heading, ship's forward speed, and ship's lateral speed. This wave drift force is pre-calculated, made into database, and used in time domain simulation. The developed simulation program is validated by comparing the computation results of a turning test in regular waves with experimental data. Using this program, turning performance in irregular waves is evaluated and sensitivities for time signal of wave elevation are investigated. Through this study, it is confirmed that the simplified method based on the MMG model including wave drift force can provide good agreement with experimental data in a practical point of view. It can be observed that the simulation results considering the lateral speed show better agreement with the experimental data than those without consideration. In the case of irregular wave condition, the turning performance can be affected by wave random phases. When the ship encounters the beam sea during the turning operation, the wave elevations at that time play an essential role in the change of ship speed and turning trajectory.

Hybrid Method for Predicting Ship Manoeuvrability in Regular Waves

2019 ◽  
Author(s):  
Tianlong Mei ◽  
Yi Liu ◽  
Manasés Tello Ruiz ◽  
Marc Vantorre ◽  
Evert Lataire ◽  
...  
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Potential Flow ◽  
Flow Theory ◽  
Regular Waves ◽  
Potential Flow Theory ◽  
Hydrodynamic Derivatives ◽  
Mmg Model ◽  
Calm Water ◽  
Wave Induced

Abstract The ship’s manoeuvring behaviour in waves is significantly different from that in calm water. In this context, the present work uses a hybrid method combining potential flow theory and Computational Fluid Dynamics (CFD) techniques for the prediction of ship manoeuvrability in regular waves. The mean wave-induced drift forces are calculated by adopting a time domain 3D higher-order Rankine panel method, which includes the effect of the lateral speed and forward speed. The hull-related hydrodynamic derivatives are determined based on a RANS solver using the double body flow model. The two-time scale method is applied to integrate the improved seakeeping model in a 3-DOF modular type Manoeuvring Modelling Group (MMG model) to investigate the ship’s manoeuvrability in regular waves. Numerical simulations are carried out to predict the turning circle in regular waves for the S175 container carrier. The turning circle’s main characteristics as well as the wave-induced motions are evaluated. A good agreement is obtained by comparing the numerical results with experimental data obtained from existing literature. This demonstrates that combining potential flow theory with CFD techniques can be used efficiently for predicting the manoeuvring behaviour in waves. This is even more true when the manoeuvring derivatives cannot be obtained from model tests when there is lack of such experimental data.

System-Based Modelling of KCS Manoeuvring in Calm Water, Current and Waves

2020 ◽  
Author(s):  
Yuting Jin ◽  
Lucas J. Yiew ◽  
Allan R. Magee ◽  
Yingying Zheng
Keyword(s):  
Water Current ◽  
Flow Solver ◽  
Wave Drift ◽  
Future State ◽  
Steady Current ◽  
Mmg Model ◽  
Calm Water ◽  
Wave Effects ◽  
Object Of Study ◽  
Water Speed

Abstract Maritime autonomous surface ships (MASS) require accurate future state projection to initiate collision-avoidance manoeuvres. Forecasts of the vessels’ trajectories and motions are fundamentally based on the mathematical manoeuvring model, which is an essential component of their hydrodynamic digital twin nowadays. Using the benchmark container ship KCS as an object of study, this paper adopts a 4-DOF modular-type manoeuvring (MMG) model to predict the vessel trajectories in calm water and under the presence of steady current and regular waves. The current effects are treated as additional ship over water speed, while the wave effects are considered by superimposing the second-order mean wave drift loads to the calm water hull hydrodynamics. The wave drift loads are solved using the potential flow solver WASIM, which is based on Rankine panel method. The computed vessel trajectories and motions are compared with available literature results and show good correlation.

scholarly journals Path following of underactuated surface ships based on model predictive control with neural network

2020 ◽  
Vol 17 (4) ◽  
pp. 172988142094595
Author(s):  
Ronghui Li ◽  
Ji Huang ◽  
Xinxiang Pan ◽  
Qionglei Hu ◽  
Zhenkai Huang
Keyword(s):  
Neural Network ◽  
Model Predictive Control ◽  
Predictive Control ◽  
Input Saturation ◽  
Path Following ◽  
Environmental Disturbances ◽  
Control Approach ◽  
Underactuated Ship ◽  
Mmg Model ◽  
The Mathematical Model

A model predictive control approach is proposed for path following of underactuated surface ships with input saturation, parameters uncertainties, and environmental disturbances. An Euler iterative algorithm is used to reduce the calculation amount of model predictive control. The matter of input saturation is addressed naturally and flexibly by taking advantage of model predictive control. The mathematical model group (MMG) model as the internal model improves the control accuracy. A radial basis function neural network is also applied to compensate the total unknowns including parameters uncertainties and environmental disturbances. The numerical simulation results show that the designed controller can force an underactuated ship to follow the desired path accurately in the case of input saturation and time-varying environmental disturbances including wind, current, and wave.

FEATURES ANALYSIS AND SYSTEM IDENTIFICATION OF MECHANOMYOGRAPHY AND ELECTROMYOGRAPHY UNDER TRANSCRANIAL MAGNETIC STIMULATION

2021 ◽  
Author(s):  
HANYANG ZHANG ◽  
YANBIAO ZHONG ◽  
YUE ZHANG ◽  
KE YANG ◽  
CHUNMING XIA ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Motor Evoked Potential ◽  
Pulse Signal ◽  
Brain Diseases ◽  
Abductor Pollicis Brevis ◽  
Mmg Model ◽  
Fourth Order Model ◽  
Electrophysiological Technique

Transcranial magnetic stimulation (TMS) is an electrophysiological technique that uses alternating magnetic fields to deliver electric current and stimulate the cerebral cortex. When TMS is used for the evaluation of brain diseases, it is necessary to detect the contraction of the corresponding muscles in the cerebral cortex stimulated by TMS, and the muscle activity referred to as motor evoked potential (MEP). This study simultaneously recorded the mechanomyography (MMG) and electromyography (EMG) from the right abductor pollicis brevis muscle during TMS with different intensities in order to observe whether the MEP parameters from MMG signals showed similar trait of EMG recordings. Moreover, the subspace method (N4SID) and transfer function were used to identify the TMS–MMG system. In this system, the input was a pulse signal of TMS, and the output was the MMG signal detected from the target muscle. The TMS–MMG system was identified as a fourth-order model. This study also analyzed the internal features of the system and demonstrated that the poles of healthy subjects were distributed in a range, and the gain increased with the increase of the TMS intensity. It was found that MMG signals can be used as diagnostic indicators of TMS, and the TMS–MMG model can be used to further explore the details of how TMS generates responses measured with MMG.

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