VI International Conference on Computational Methods in Marine Engineering (MARINE 2015) Rome, Italy, 15-17 June, 2015
http://hdl.handle.net/2117/331024
2024-03-28T18:55:26ZUnscented kalman filltering for autonomous underwater navigation
http://hdl.handle.net/2117/332628
Unscented kalman filltering for autonomous underwater navigation
Allotta, Benedetto; Caiti, Andrea; Constanzi, Riccardo; Fanelli, Francesco; Fenucci, Davide; Meli, Enrico; Ridolfi, Alessandro
The availability of a high-performance navigation state estimator is fundamental to Autonomous Underwater Vehicles (AUVs), especially when multiple vehicles
are involved in autonomous tasks. The underwater environment further complicates the estimation
process, reducing the number of available sensors.
In this paper, a navigation filter based on the Unscented Kalman Filter (UKF) and rely- ing on AUV
onboard sensors is proposed. The performance of the presented solution is evaluated exploiting
experimental data acquired by the two Typhoon AUVs, developed and built by the Department of
Industrial Engineering (DIEF) of the University of Flo- rence within the THESAURUS Tuscany Region
Project for exploration and surveillance of underwater archaeological sites, during the
International workshop Breaking the Sur- face 2014 (BtS 2014) held in Biograd na Moru
(Croatia) in October 2014. An offline comparison between the estimates given by the proposed
filter and those computed by a standard navigation algorithm (based on the Extended Kalman Filter,
EKF) is presented. The demonstration performed at BtS 2014 constitutes a preliminary test of
cooperative navigation between the two AUVs. The obtained results show that the UKF offers promis-
ing accuracy improvements with respect to the EKF; in addition, the computational load required is
affordable by the typical AUV hardware. According to the achieved results, the proposed algorithm
will be implemented on the Typhoon AUVs and tested online.
2020-11-19T16:36:55ZAllotta, BenedettoCaiti, AndreaConstanzi, RiccardoFanelli, FrancescoFenucci, DavideMeli, EnricoRidolfi, AlessandroThe availability of a high-performance navigation state estimator is fundamental to Autonomous Underwater Vehicles (AUVs), especially when multiple vehicles
are involved in autonomous tasks. The underwater environment further complicates the estimation
process, reducing the number of available sensors.
In this paper, a navigation filter based on the Unscented Kalman Filter (UKF) and rely- ing on AUV
onboard sensors is proposed. The performance of the presented solution is evaluated exploiting
experimental data acquired by the two Typhoon AUVs, developed and built by the Department of
Industrial Engineering (DIEF) of the University of Flo- rence within the THESAURUS Tuscany Region
Project for exploration and surveillance of underwater archaeological sites, during the
International workshop Breaking the Sur- face 2014 (BtS 2014) held in Biograd na Moru
(Croatia) in October 2014. An offline comparison between the estimates given by the proposed
filter and those computed by a standard navigation algorithm (based on the Extended Kalman Filter,
EKF) is presented. The demonstration performed at BtS 2014 constitutes a preliminary test of
cooperative navigation between the two AUVs. The obtained results show that the UKF offers promis-
ing accuracy improvements with respect to the EKF; in addition, the computational load required is
affordable by the typical AUV hardware. According to the achieved results, the proposed algorithm
will be implemented on the Typhoon AUVs and tested online.Towards next generation intervention autonomous underwater vehicles (I-AUV): development of innovative mobile manipulation techniques
http://hdl.handle.net/2117/332626
Towards next generation intervention autonomous underwater vehicles (I-AUV): development of innovative mobile manipulation techniques
Allotta, Benedetto; Conti, Roberto; Constanzi, Riccardo; Fanelli, Francesco; Meli, Enrico; Ridolfi, Alessandro
Autonomous underwater manipulation with free floating base is still an open
topic of research; dynamic manipulation tasks, executed maintaining relevant vehicle
velocities, offer an additional challenge. The focus of this paper is the modelling and the
control of an Intervention Autonomous Underwater Vehicle (I-AUV). An accurate model of the whole
system has been developed, including vehicle-fluid interaction. A control strategy for the
whole I-AUV system is proposed, comprising a suitable grasp planning strategy. The performances of
the I-AUV control system have been analysed in details
by means of simulation of a dynamic manipulation task.
2020-11-19T16:30:01ZAllotta, BenedettoConti, RobertoConstanzi, RiccardoFanelli, FrancescoMeli, EnricoRidolfi, AlessandroAutonomous underwater manipulation with free floating base is still an open
topic of research; dynamic manipulation tasks, executed maintaining relevant vehicle
velocities, offer an additional challenge. The focus of this paper is the modelling and the
control of an Intervention Autonomous Underwater Vehicle (I-AUV). An accurate model of the whole
system has been developed, including vehicle-fluid interaction. A control strategy for the
whole I-AUV system is proposed, comprising a suitable grasp planning strategy. The performances of
the I-AUV control system have been analysed in details
by means of simulation of a dynamic manipulation task.Dynamical simulation and optimization of double-helical AUV
http://hdl.handle.net/2117/332625
Dynamical simulation and optimization of double-helical AUV
Auzins, Janis; Eimanis, Marcis
The paper presents an original design of autonomous underwater vehicles where
thrust forc is created by the helicoidal shape of hull rather than screw propellers. The contra-
rotating bow and stern parts create propulsion force. The middle part of the vehicle, which is
built from elastic material, contains a Cardan joint which controls bending drives (actuators). The
controlled bending of the hull allows the maneuvering of the vehicle. A bending drive velocity
control algorithm for the automatic control of the vehicle movement direction is
proposed. The dynamics of AUV are simulated using multibody simulation software MSC
Adams. For the simulation of water resistance forces and torques the surrogate
polynomial metamodels are created on the basis of computer experiments with CFD
software. The simulation results are compared with measurements of the AUV prototype, created at
Institute of Mechanics of Riga Technical University. Experiments with the prototype
showed good agreement with simulation results and confirmed the effectiveness and the future
potential of
the proposed principle.
2020-11-19T16:24:40ZAuzins, JanisEimanis, MarcisThe paper presents an original design of autonomous underwater vehicles where
thrust forc is created by the helicoidal shape of hull rather than screw propellers. The contra-
rotating bow and stern parts create propulsion force. The middle part of the vehicle, which is
built from elastic material, contains a Cardan joint which controls bending drives (actuators). The
controlled bending of the hull allows the maneuvering of the vehicle. A bending drive velocity
control algorithm for the automatic control of the vehicle movement direction is
proposed. The dynamics of AUV are simulated using multibody simulation software MSC
Adams. For the simulation of water resistance forces and torques the surrogate
polynomial metamodels are created on the basis of computer experiments with CFD
software. The simulation results are compared with measurements of the AUV prototype, created at
Institute of Mechanics of Riga Technical University. Experiments with the prototype
showed good agreement with simulation results and confirmed the effectiveness and the future
potential of
the proposed principle.Numerical prediction of extreme loads on flap-type energy converters
http://hdl.handle.net/2117/332624
Numerical prediction of extreme loads on flap-type energy converters
Marrone, Salvatore; Colagrossi, Andrea; Baudry, Virginie; Le Touzé, David; Rosi, Emanuele
In the recent years an increasing interest has been devoted to the study of the
feasibility and relevance in combining wave energy converters with coastal structures. The present
work addresses the evaluation by numerical simulation of the extreme loads acting on a flap-type
energy converter. To this aim the SPH model can be an optimal candidate: its Lagrangian character
allows for an accurate description of the extreme breaking wave acting on the structure while its
meshless feature permits an easy interaction of the fluid with moving rigid bodies such as the
rotating flap converter. As a first approach, extreme wave characteristics have been computed
using statistical offshore wave elevation data. Then, the wave has been generated in a 2D
numerical wave tank through a piston wave- maker. Loads on the flaps are computed and
analysed considering a moving or fixed flap. A sensitivity analysis of the results has been
performed considering different impact dynamics (e.g. wave impact occurring before or after wave
breaking). The most critical cases found in the 2D analysis have been reproduced with a fully 3D SPH model.
2020-11-19T16:21:29ZMarrone, SalvatoreColagrossi, AndreaBaudry, VirginieLe Touzé, DavidRosi, EmanueleIn the recent years an increasing interest has been devoted to the study of the
feasibility and relevance in combining wave energy converters with coastal structures. The present
work addresses the evaluation by numerical simulation of the extreme loads acting on a flap-type
energy converter. To this aim the SPH model can be an optimal candidate: its Lagrangian character
allows for an accurate description of the extreme breaking wave acting on the structure while its
meshless feature permits an easy interaction of the fluid with moving rigid bodies such as the
rotating flap converter. As a first approach, extreme wave characteristics have been computed
using statistical offshore wave elevation data. Then, the wave has been generated in a 2D
numerical wave tank through a piston wave- maker. Loads on the flaps are computed and
analysed considering a moving or fixed flap. A sensitivity analysis of the results has been
performed considering different impact dynamics (e.g. wave impact occurring before or after wave
breaking). The most critical cases found in the 2D analysis have been reproduced with a fully 3D SPH model.On the sph modeling of flow over cylinder beneath to a free-surface
http://hdl.handle.net/2117/332623
On the sph modeling of flow over cylinder beneath to a free-surface
Ozbulut, M.; Tofighi, N.; Goren, O.; Yildiz, M.
This work aims to model flow around rigid cylinder beneath to a free surface
by using a particle based Lagrangian method, namely, Smoothed Particle Hydrodynamics (SPH) which
has clear advantages on modeling nonlinear violent free surface problems. This problem
which is also regarded as 2-d wave making problem in marine hydrodynamics literature is carried out
for three different positions of cylinder centre with two different Froude numbers. The fluid
motion is governed by continuity and Eulers equations while Weakly Compressible SPH (WCSPH)
approximation together with artificial viscosity term is employed for the numerical
discretization of the problem domain. Hybrid Velocity- updated XSPH and Articial Particle
Displacement (VXSPH+APD) correction algorithm
[1] and standard density correction treatment is also added into the numerical scheme.
The Reynolds number is chosen as close to 200 for all cases where three dimensionality first starts
to be effective in the flow domain [2]. As the flow characteristics are metastable
[12], the free-surface deformations, drag and the lift force on the body shows
periodic variation during the evolution of the flow. Free-surface deformations at the
maximum and minimum lift instants are compared with the results of Reichl et.al. [12] for the
first two cases. The last case considers a higher Froude number and deeper cylinder position where
lift and drag forces are compared with the findings of [22]. It is observed that the obtained
free-surface profiles, mean values of drag and lift forces give consistent results
in a good with the referred literature data.
2020-11-19T16:16:57ZOzbulut, M.Tofighi, N.Goren, O.Yildiz, M.This work aims to model flow around rigid cylinder beneath to a free surface
by using a particle based Lagrangian method, namely, Smoothed Particle Hydrodynamics (SPH) which
has clear advantages on modeling nonlinear violent free surface problems. This problem
which is also regarded as 2-d wave making problem in marine hydrodynamics literature is carried out
for three different positions of cylinder centre with two different Froude numbers. The fluid
motion is governed by continuity and Eulers equations while Weakly Compressible SPH (WCSPH)
approximation together with artificial viscosity term is employed for the numerical
discretization of the problem domain. Hybrid Velocity- updated XSPH and Articial Particle
Displacement (VXSPH+APD) correction algorithm
[1] and standard density correction treatment is also added into the numerical scheme.
The Reynolds number is chosen as close to 200 for all cases where three dimensionality first starts
to be effective in the flow domain [2]. As the flow characteristics are metastable
[12], the free-surface deformations, drag and the lift force on the body shows
periodic variation during the evolution of the flow. Free-surface deformations at the
maximum and minimum lift instants are compared with the results of Reichl et.al. [12] for the
first two cases. The last case considers a higher Froude number and deeper cylinder position where
lift and drag forces are compared with the findings of [22]. It is observed that the obtained
free-surface profiles, mean values of drag and lift forces give consistent results
in a good with the referred literature data.Design of ship-engine-propeller simultaneous matching and development of a propeller and engine selecting system
http://hdl.handle.net/2117/332592
Design of ship-engine-propeller simultaneous matching and development of a propeller and engine selecting system
Lin, Shiyao; Sun, Jianglong; Xie, De
A process to design ship-engine-propeller simultaneous matching is proposed in
this paper. The design process treats the whole system as an assembly of the ship-propeller
subsystem and the engine-propeller subsystem in which relationships between rotational
speed of the propeller and advancing speed of the ship are found and expressed as N-V curves.
Furthermore, databases of propellers and engines are established and connected to self
developed user interface to calculate simultaneous matching conditions in loops and the
matching points are collected to form a selection pool where user can conduct selection. An example
to select a propeller and an engine for a 25,000t bulk carrier using the developed
selecting system is described and the outputs are listed and analyzed. The selected pair of the
propeller and the engine is efficient and comprehensive compared with other instances in the
databases.
2020-11-19T12:41:48ZLin, ShiyaoSun, JianglongXie, DeA process to design ship-engine-propeller simultaneous matching is proposed in
this paper. The design process treats the whole system as an assembly of the ship-propeller
subsystem and the engine-propeller subsystem in which relationships between rotational
speed of the propeller and advancing speed of the ship are found and expressed as N-V curves.
Furthermore, databases of propellers and engines are established and connected to self
developed user interface to calculate simultaneous matching conditions in loops and the
matching points are collected to form a selection pool where user can conduct selection. An example
to select a propeller and an engine for a 25,000t bulk carrier using the developed
selecting system is described and the outputs are listed and analyzed. The selected pair of the
propeller and the engine is efficient and comprehensive compared with other instances in the
databases.Numerical optimisation of an adaptable stern geometry for a RoPAX vessel
http://hdl.handle.net/2117/332591
Numerical optimisation of an adaptable stern geometry for a RoPAX vessel
Haffermann, Dieke; Frömming, Knut; Martinsen, Kay
New regulations ruling energy efficiency on board ships and the development of oil prices underline the importance of fuel economy to all commercial ship operations. The design of RoPAX ships is usually optimised for one specific or a small number of operational conditions or load cases which typically yields less than optimal performance for other, off-design operational conditions. Practically, the operational conditions like ship speed and draught vary considerably over time. To obtain an optimal hydrodynamic performance over a range of conditions a hullform which is capable to adapt to different conditions would be desirable. For RoPAX vessels, hydrodynamic model tests have shown that a small change in the aft-hull, especially of the trim-wedge geometry can have a significant influence on the ship’s dynamic trim and reduce the resistance in off-design conditions. Characteristic form data as displacement, longitudinal center of buoyancy, longitudinal center of floatation are just imperceptively influenced by this change. This calls for the development of a baseline design which allows adapting the form using adaptive structures and materials. The collaborative EU FP7 project ADAM4EVE - Adaptive and smart
2020-11-19T12:37:29ZHaffermann, DiekeFrömming, KnutMartinsen, KayNew regulations ruling energy efficiency on board ships and the development of oil prices underline the importance of fuel economy to all commercial ship operations. The design of RoPAX ships is usually optimised for one specific or a small number of operational conditions or load cases which typically yields less than optimal performance for other, off-design operational conditions. Practically, the operational conditions like ship speed and draught vary considerably over time. To obtain an optimal hydrodynamic performance over a range of conditions a hullform which is capable to adapt to different conditions would be desirable. For RoPAX vessels, hydrodynamic model tests have shown that a small change in the aft-hull, especially of the trim-wedge geometry can have a significant influence on the ship’s dynamic trim and reduce the resistance in off-design conditions. Characteristic form data as displacement, longitudinal center of buoyancy, longitudinal center of floatation are just imperceptively influenced by this change. This calls for the development of a baseline design which allows adapting the form using adaptive structures and materials. The collaborative EU FP7 project ADAM4EVE - Adaptive and smartNumerical models for ship dynamic positioning
http://hdl.handle.net/2117/332590
Numerical models for ship dynamic positioning
Donnarumma, S.; Martelli, M.; Vignolo, S.
One of the best ways to design marine control systems before the construction of a
ship is the use of simulation techniques. The paper presents two numerical models used
to develop and test, in the preliminary design phase, a dynamic positioning (DP) system for marine
vehicles. In particular, it refers to a surface vessel equipped with a conventional propulsion
configuration, consisting of two controllable pitch propellers, two rudders and a single bow-
thruster. For such a vessel, the DP system is required to manage the actuators in order to obtain
a good dynamic positioning performance at zero-speed with moderate weather conditions. In order to
verify control and allocation logics, two numerical models, with different degrees of details, have
been developed and used in distinct steps. Several sub-systems as ship dynamics, propulsion plant,
controller and environmental disturbances have been implemented making use of suitable mathematical
models linked each other in order to take into account their mutual interactions. Eventually,
simulation results are shown and critically compared in order to better
understand the points of strength and weakness of the two proposed models.
2020-11-19T12:31:37ZDonnarumma, S.Martelli, M.Vignolo, S.One of the best ways to design marine control systems before the construction of a
ship is the use of simulation techniques. The paper presents two numerical models used
to develop and test, in the preliminary design phase, a dynamic positioning (DP) system for marine
vehicles. In particular, it refers to a surface vessel equipped with a conventional propulsion
configuration, consisting of two controllable pitch propellers, two rudders and a single bow-
thruster. For such a vessel, the DP system is required to manage the actuators in order to obtain
a good dynamic positioning performance at zero-speed with moderate weather conditions. In order to
verify control and allocation logics, two numerical models, with different degrees of details, have
been developed and used in distinct steps. Several sub-systems as ship dynamics, propulsion plant,
controller and environmental disturbances have been implemented making use of suitable mathematical
models linked each other in order to take into account their mutual interactions. Eventually,
simulation results are shown and critically compared in order to better
understand the points of strength and weakness of the two proposed models.Multi-objective hull-form optimization using kriging on noisy computer experiments
http://hdl.handle.net/2117/332589
Multi-objective hull-form optimization using kriging on noisy computer experiments
Scholcz, Thomas P.; Gornicz, Tomasz; Veldhuis, Christian
Meta-modelling is a key technique for efficient multi-objective optimization
in ship design projects using CFD. However, objective functions computed with CFD are not
deterministic functions but contain random scatter about a smooth trend. Kriging is a meta-model
technique that is well suited for numerical experiments with deterministic errors that can be
perceived as random scatter due to varying input parameters. Sim- ple Kriging, universal
kriging and polynomial regression are used to obtain approximate Pareto-fronts from the hull-form
optimization of a chemical tanker including free-surface effects. Cross-validation is used to
assess the quality of the meta-models and the meta- model approximations of the
Pareto-fronts are verified. It is found that cross-validation can be used to select the best
meta-model but should not be used to estimate the true error of the approximation in case
the design of experiment is too coarse. The approach is used in practice in order to accelerate
the ship design process and to obtain more efficient
ships with less vibration hindrance.
2020-11-19T12:28:59ZScholcz, Thomas P.Gornicz, TomaszVeldhuis, ChristianMeta-modelling is a key technique for efficient multi-objective optimization
in ship design projects using CFD. However, objective functions computed with CFD are not
deterministic functions but contain random scatter about a smooth trend. Kriging is a meta-model
technique that is well suited for numerical experiments with deterministic errors that can be
perceived as random scatter due to varying input parameters. Sim- ple Kriging, universal
kriging and polynomial regression are used to obtain approximate Pareto-fronts from the hull-form
optimization of a chemical tanker including free-surface effects. Cross-validation is used to
assess the quality of the meta-models and the meta- model approximations of the
Pareto-fronts are verified. It is found that cross-validation can be used to select the best
meta-model but should not be used to estimate the true error of the approximation in case
the design of experiment is too coarse. The approach is used in practice in order to accelerate
the ship design process and to obtain more efficient
ships with less vibration hindrance.A scaling procedure for modern propeller designs
http://hdl.handle.net/2117/332588
A scaling procedure for modern propeller designs
Helma, Stephan
The extrapolation procedures currently used to scale propeller characteristics tested at
model scale to their full scale performances are either based on a statistical [1], the Lerbs-
Meyne [2] or the recently developed strip method [3].
With the emergence of so-called unconventional propellers and different design strategies
associated with them, it has been questioned whether the assumptions used in these scaling methods
are still universally valid. E.g. with tip and root unloading employed, the circulation
distribution deviates from the optimum, which is assumed by the Lerbs-Meyne method; more modern
profiles show a different camber distribution and hence the drag coefficient must be aligned with
the hydrodynamic inflow angle and not with the pitch to diameter ratio as assumed by the strip
method (and implicitly by the ITTC 1978 method [4]).
The work presented still uses the assumption of the equivalent profile and will
explain a modified scaling procedure showing a way to calculate the hydrodynamic inflow angle
solely from one open-water test conducted at a constant Reynolds number. Finally exemplary results
comparing a propeller of conventional type with a recent propeller designs will also be shown.
The new proposed method shows a superior performance when compared to other scaling
methods.
2020-11-19T12:25:03ZHelma, StephanThe extrapolation procedures currently used to scale propeller characteristics tested at
model scale to their full scale performances are either based on a statistical [1], the Lerbs-
Meyne [2] or the recently developed strip method [3].
With the emergence of so-called unconventional propellers and different design strategies
associated with them, it has been questioned whether the assumptions used in these scaling methods
are still universally valid. E.g. with tip and root unloading employed, the circulation
distribution deviates from the optimum, which is assumed by the Lerbs-Meyne method; more modern
profiles show a different camber distribution and hence the drag coefficient must be aligned with
the hydrodynamic inflow angle and not with the pitch to diameter ratio as assumed by the strip
method (and implicitly by the ITTC 1978 method [4]).
The work presented still uses the assumption of the equivalent profile and will
explain a modified scaling procedure showing a way to calculate the hydrodynamic inflow angle
solely from one open-water test conducted at a constant Reynolds number. Finally exemplary results
comparing a propeller of conventional type with a recent propeller designs will also be shown.
The new proposed method shows a superior performance when compared to other scaling
methods.