Simulated Maneuvers Research Articles

Longitudinal Velocity Tracking Control of a 4WID Electric Vehicle

A novel four-wheel independent drive (4WID) electric vehicle (EV) is proposed as an autonomous ground vehicle (AGV) in this paper. Since longitudinal motion control is the fundamental problem of autonomous vehicle control, a traditional sliding mode control (SMC) algorithm and an improved adaptive sliding mode control (ASMC) algorithm using Radial Basis Function (RBF) neural network are applied to longitudinal velocity tracking controller design. To evaluate the performance of the designed controllers for the 4WID EV, two simulation maneuvers are carried out including straight line condition and single lane-change condition. The simulation results indicate that the longitudinal velocity tracking controller using ASMC has smaller tracking error and better disturbance rejection performance than SMC.

Right Turn Coeficient Evaluation Analysis on Intersection capasity formula at Indonesia Highway Capasity Manual 1997 Using Vehicle Tracking Simulation

The aims of this study are to evaluate the the right-turn coefficients at intersection capasity formula by Indonesia Highway Capacity Manual (MKJI 1997). Therefore, it is necessary for analysis that examines right-turn coefficient values in intersection capacity function. The simulation with many various geometric intersections defined by many scenarios using vehicle tracking application program, which increase the space maneuver vehicle at the intersection includes: 1) widen approach lane; 2) add a right-turn lane; and 3) backward median in each approach. Intersection performance Analysis will produce degree of saturation that is affected by right-turn coefficient according to the simulated vehicle maneuver using new formula. The study can be concluded that the intersection changes the right-turn factor adjustment which was originally set with the value based on linear function being a log function. According to the new function, Prt Less 2,5% right turn vehicle make significant decrease of intersection capacity, that why, it makes many conflict based on opposite traffic from other approach. In the other side, if Prt more then 2,5%, it makes increase intersection capacity because intersection space used to right turn vehicles.

A Mobile Manoeuvring Simulation System for Design, Verification and Validation of Marine Automation Systems

Applications for SIL and HIL testing in design, verification, and validation of marine systems are expected to increase. With this in view the concept for a mobile simulation system is presented, which aims at enhancing factory and on board simulation based testing. A modular network-based system architecture is proposed providing: real-time process simulation, hardware interfaces, test tools, a mobile bridge console, and 3D-visualization. For the purpose of flexible solutions a modular and scalable approach to simulating ship motion in six degrees of freedom is incorporated. Finally preliminary modelling and simulation results from the current design stage are presented.

Design of a safety operational envelope protection system for a submarine

A safety operational envelope (SOE) is an area that guarantees the safety of a submarine from accidents, such as jamming and flooding. In this study, a submarine envelope protection system (EPS) was designed to prevent submarine excursion from the SOE. Modeling of the hull force, propeller force, and main ballast tank blowing was performed. The SOE was established based on a crash stop and emergency rising maneuver simulation. In the estimation model, a linear compensator and neural network are employed to estimate the submarine dynamics. The command limit is calculated using the estimation model and the dynamic trim algorithm, and it is restricted by the limit avoidance. The EPS was applied to a submarine maneuvering simulation program and its performance was verified by a depth change simulation. The designed EPS prevents the submarine from exceeding the limit boundary and the control system can thereby enhance the operational stability.

Prediction of the turning and zig-zag maneuvering performance of a surface combatant with URANS

The main objective of this study is to investigate the turning and zig-zag maneuvering performance of the well-known naval surface combatant DTMB (David Taylor Model Basin) 5415 hull with URANS (Unsteady Reynolds-averaged Navier-Stokes) method. Numerical simulations of static drift tests have been performed by a commercial RANS solver based on a finite volume method (FVM) in an unsteady manner. The fluid flow is considered as 3-D, incompressible and fully turbulent. Hydrodynamic analyses have been carried out for a fixed Froude number 0.28. During the analyses, the free surface effects have been taken into account using VOF (Volume of Fluid) method and the hull is considered as fixed. First, the code has been validated with the available experimental data in literature. After validation, static drift, static rudder and drift and rudder tests have been simulated. The forces and moments acting on the hull have been computed with URANS approach. Numerical results have been applied to determine the hydrodynamic maneuvering coefficients, such as, velocity terms and rudder terms. The acceleration, angular velocity and cross-coupled terms have been taken from the available experimental data. A computer program has been developed to apply a fast maneuvering simulation technique. Abkowitz\'s non-linear mathematical model has been used to calculate the forces and moment acting on the hull during the maneuvering motion. Euler method on the other hand has been applied to solve the simultaneous differential equations. Turning and zig-zag maneuvering simulations have been carried out and the maneuvering characteristics have been determined and the numerical simulation results have been compared with the available data in literature. In addition, viscous effects have been investigated using Eulerian approach for several static drift cases.

Manoeuvring model of an estuary container vessel with two interacting Z-drives

A 6 degrees of freedom manoeuvring model of an estuary container vessel was implemented in the inland navigation simulator Lara at Flanders Hydraulics Research (FHR). The container vessel, with dimensions 110 m × 17.5 m × 4.5 m, is equipped with two Z-drives, each one consisting of two contra rotating propellers. Both Z-drives have a 360° azimuth angle of operation during manoeuvring. The mathematical manoeuvring model was built to cover all degrees of operation. This required the execution of a significant number of captive model tests in the shallow water towing tank of FHR (in co-operation with Ghent University). Based on these tests a new mathematical manoeuvring model was built to cover all effects of operation, including the interaction effects between the two Z-drives. The new mathematical model was implemented in the simulator and both fast time and real time manoeuvring simulations have been carried out. A paper discussing the validation of the manoeuvring model has been presented during MARSIM 2015 (Vos, Delefortrie, and Van Hoydonck in Validation of the manoeuvring behaviour on an estuary vessel. MARSIM, Newcastle, 2015). The present paper discusses the details of the manoeuvring model, with emphasis on the interaction effects between the Z-drives and the influence on the hydrodynamic forces.

Propeller/rudder interaction with direct and coupled CFD/potential flow propeller approaches, and application to a zigzag manoeuvre

ABSTRACTThis paper investigates a coupled computational fluid dynamics (CFD)/potential propeller code approach to simulate maneuvers of ships. While this approach is successful in submarines, the concept has not been evaluated before for cases where an object (the rudder) is immersed in the wake. The study uses the CFD code REX and the propeller code PUF-14 applied to propeller/rudder interactions in open water configuration and to a 15/1 zigzag maneuver for the KCS container ship. Self-propulsion results, and motions, forces, moments and mean flow field during the maneuver agree well with experiments and discretized propeller simulations. The approach is an effective and economical way to perform direct simulation of surface ship maneuvers, providing CPU time savings approaching an order of magnitude. Massively separated rudder flows may not perform as well, since the propeller turbulence reaching the rudder is under-predicted in the coupled approach.

Identification-based simplified model of large container ships using support vector machines and artificial bee colony algorithm

The 6 degrees of freedom (DOF) model with a high degree of complexity for capturing ship dynamics is generally able to track the nonlinear and coupling dynamics of ships. However, the 6 DOF model makes challenges in estimating model coefficients and designing the model-based control. Therefore, simplified ship dynamic models within allowed accuracy are essential. This paper simplified the 6 DOF nonlinear dynamic model of ships into two decoupled models including the speed model and the steering model through reasonable assumptions. Those models were tested through maneuvering simulations of a container ship with a 4 DOF dynamic model. Support vector machines (SVM) optimized by the artificial bee colony algorithm (ABC) was used to identify parameters of speed and steering models by analyzing the rudder angle, propeller shaft speed, surge and sway velocities, and yaw rate from simulated data extracted from a series of maneuvers made by the container ship. Comparisons with the first order linear and nonlinear Nomoto models show that the simplified nonlinear steering model can capture more complicated dynamics and performs better. Additionally, comparisons among three different parameter identification methods demonstrate similar identification results but the different performance involving the applicability and effectiveness. SVM optimized by ABC is relatively convenient and effective for parameter identification of ship simplified dynamic models.

Analysis of the asymmetric behavior of propeller–rudder system of twin screw ships by CFD

The interference between the hull, propeller and rudder remarkably affects the control and maneuvering capabilities of marine vehicles. In case of twin screw/twin rudder ships, the asymmetric evolution of the wake past the hull causes the asymmetric functioning of the propeller–rudder system. Systematic investigations on this aspect for twin screw ships are limited. Available experimental data carried out on simplified hull–propeller–rudder system and captive model tests do not allow to completely understand the fluid mechanism at the basis of the hydrodynamic interaction that should be taken into account in simplified maneuvering mathematical models for preliminary predictions. In this paper the hull–propeller–rudder interactions phenomena for a twin screw/twin rudder model are investigated by URANS simulations, with a particular focus on the asymmetry of the propeller–rudder system. To this aim, captive model tests consisting of pure rudder and coupled drift–yaw motions corresponding to the steady phases of turning circle maneuvers at different rudder angles (δ=15°÷35°) are performed at the speed correspondent to Fr=0.265. Moreover, a free running maneuvering simulation is also performed to gain more insight on the transient phase of the maneuver. An identity rudder lift methodology is applied to synthesize the hull–propeller–rudder interactions by means of a flow straightening coefficient; the analysis highlights that these effects are weak and invariant with respect to the rudder angle on the windward shaft, whereas on the leeward side these effects are extremely sensitive to the evolution of the hull and propeller wake.

Measures to diminish the parameter drift in the modeling of ship manoeuvring using system identification

System identification provides an effective way to predict the ship manoeuvrability. In this paper several measures are proposed to diminish the parameter drift in the parametric identification of ship manoeuvring models. The drift of linear hydrodynamic coefficients can be accounted for from the point of view of dynamic cancellation, while the drift of nonlinear hydrodynamic coefficients is explained from the point of view of regression analysis. To diminish the parameter drift, reconstruction of the samples and modification of the mathematical model of ship manoeuvring motion are carried out. Difference method and the method of additional excitation are proposed to reconstruct the samples. Using correlation analysis, the structure of a manoeuvring model is simplified. Combined with the measures proposed, support vector machines based identification is employed to determine the hydrodynamic coefficients in a modified Abkowitz model. Experimental data from the free-running model tests of a KVLCC2 ship are analyzed and the hydrodynamic coefficients are identified. Based on the regressive model, simulation of manoeuvres is conducted. Comparison between the simulation results and the experimental results demonstrates the validity of the proposed measures.

Modeling of chemical reactions between polyatomic molecules for atmospheric entry simulations with direct simulation Monte Carlo

For the simulation of atmospheric entry maneuvers at Mars and Saturn’s Titan, the chemistry modeling of polyatomic molecules is implemented in the direct simulation Monte Carlo method within the reactive plasma flow solver PICLas. An additional reaction condition as well as the consideration of the vibrational degrees of freedom is described in the context of the total collision energy model. The treatment of reverse exchange and recombination reactions is discussed, where the low temperature exponent of the Arrhenius fit for methane dissociation limited the calculation of the reaction probability at relevant temperatures. An alternative method based on the equilibrium constant is devised. The post-reaction energy redistribution is performed under the assumption of equipartition of the remaining collisional energy. The implementation is verified for several reaction paths with simple reservoir simulations. Finally, the feasibility of the new chemistry model is demonstrated by a simulation of a trajectory point of Huygens probe at Titan.

Maneuvering Support System for an Amphibian Vehicle – Warning Display to Prevent Rough Maneuvers –

[abstFig src='/00290003/14.jpg' width='300' text='Amphibian vehicle maneuvering simulator' ] This study proposes a maneuvering support system for an amphibian vehicle by applying a nonlinear state feedback control law for vehicle trajectory control. We consider that the vehicle should not drift sideways for good driving performance. To derive a nonlinear state feedback control law, we have defined ‘Maneuvering Trajectory’ as an additional reference trajectory that is generated by the driver’s maneuver. We have constructed a Lyapunov-like function for the trajectory control system. In this paper, we construct a vehicle-maneuvering simulator and set a clockwise circular reference trajectory. The efficiency of the proposed maneuvering support system is shown in the maneuvering simulations. We consider the case where the propulsive forces of the vehicle have limited influence on maneuverability. A new warning display system is proposed so that the driver can recognize if his or her maneuver is not suitable. Then, we examine the feasibility of the proposed warning display system through several simulations.

Validation of ship manoeuvring models using metamodels

This paper describes how simplified auxiliary models—metamodels—can be used to create benchmarks for validating ship manoeuvring simulation models. A metamodel represents ship performance for a limited range of parameters, such as rudder angles and surge velocity. In contrast to traditional system identification methods, metamodels are identified from multiple trial recordings, each containing data on the ship’s inherent dynamics (similar for all trials) and random disturbances such as environmental effects and slightly different loading conditions. Thus, metamodels can be used to obtain these essential data, where simple averaging is not possible. In addition, metamodels are used to represent a ship’s behaviour and not to obtain physical insights into ship dynamics. The experimental trials used for the identification of metamodels can be found in in-service recorded data. After the metamodel is identified, it is used to simulate trials without substantial deviations from the ship state parameters used for the identification. Subsequently, the predictions of the metamodels are compared with the predictions of a tested manoeuvring simulation model. We present two case studies to demonstrate the application of metamodels for moderate turning motions of two ships.

Study on driver model for hybrid truck based on driving simulator experimental results

In this paper, a proposed car-following driver model taking into account some features of both the compensatory and anticipatory model representing the human pedal operation has been verified by driving simulator experiments with several real drivers. The comparison between computer simulations performed by determined model parameters with the experimental results confirm the correctness of this mathematical driver model and identified model parameters. Then the driver model is joined to a hybrid vehicle dynamics model and the moderate car following maneuver simulations with various driver parameters are conducted to investigate influences of driver parameters on vehicle dynamics response and fuel economy. Finally, major driver parameters involved in the longitudinal control of drivers are clarified.

선박의 조종특성을 고려한 운항안전성능의 수치화 방법에 관한 연구

Recently, ship owners are requiring an assessment of sailing safety of a ship from an analysis considering maneuverability and environmental loads etc. In this paper, we propose a new approach to assess sailing safety by considering the prescribed parameters. The concept of sailing safety is developed from DP capability analysis and is based on the maneuvering simulations. While the ship is continuously disturbed due to irregular environmental loads during the simulations, it is steered to keep its course along the way points assumed along a straight path. After relative distances between four edges of the ship and allowable safety boundaries are calculated for 3 hours, the minimum values are obtained. The minimum distances are marked on a polar chart and we call this a quantified safe operation judgment chart which indicates quantified sailing safety.

Innovative Fast Time Simulation Tools for Briefing / Debriefing in Advanced Ship Handling Simulator Training and Ship Operation

The innovative “Simulation-Augmented Manoeuvring Design, Monitoring & Control” system (SAMMON) based on Fast Time Simulation (FTS) technology was developed at the Institute for Innovative Ship Simulation and Maritime Systems (ISSIMS) of the Maritime Simulation Centre Warnemuende MSCW. The system consists of software modules for (a) Manoeuvring Design & Planning, (b) Monitoring & Control based on Multiple Dynamic Prediction and (c) Trial & Training. It is based on complex ship dynamic models for rudder, thruster or engine manoeuvre simulation under different environmental conditions. It is an effective tool for lecturing and demonstrating ship's motion characteristics, as well as for ship handling simulator training. It allows the trainee to immediately see the results of the actual rudder, engine or thruster commands, without having to wait for the real-time response of the vessel. The Maritime Simulation Centre of AIDA Cruises at Rostock/Germany and the CSMART Center for Simulator Maritime Training of Carnival Corporation at Almere/NL have some experience with the use of this new technology to improve simulator training in Advanced Ship Handling Training courses. Examples of its application in briefing/debriefing and introductory lectures for simulator exercises specifically for typical cruise ships with Twin-Screw and Rudder systems will be presented in the paper and at the conference.

Effect of Engine Output on Maneuverability of a VLCC in Still Water and Adverse Weather Conditions

In this study, an MMG-based maneuvering simulation method (Yasukawa and Yoshimura, J Mar Sci Technol 20(1):37–52, 1) was used to investigate the maneuverability of a VLCC in still water and adverse weather conditions. Specifically, the investigation involved a situation where the engine output of a VLCC was significantly reduced owing to advances in energy-saving technology. First, a VLCC with 30% reduced Energy Efficiency Design Index (EEDI) (IMO MEPC 63/23, Annex 8, Resolution MEPC.212(63), 2012 guidelines on the method of calculation on the attained EEDI for New Ships, 2) (Step3) is actually planned to the conventional VLCC (Step0) by adoption of energy efficiency devices, a large-diameter and low-revolution propeller, etc. Next, maneuvering simulations of two ships (Step0 and Step3) were performed in still water and adverse weather conditions. It was observed that Step3 satisfied IMO maneuvering criteria in the still water condition. However, the maneuverability of Step3 was worse than that of Step0 since the rudder force was reduced owing to the low propeller load, which resulted from the small engine output. Additionally, steady-state sailing performance of Step3 in adverse weather conditions, such as check helm, hull drift angle, and speed drop, generally worsened when compared with those of Step0. Furthermore, course changing ability also deteriorated in the case of Step3. However, the difference between the trajectories of Step0 and Step3 reduced with respect to the large Beaufort scale since the difference in the rudder force became less noticeable owing to the presence of large external lateral forces caused by strong winds and waves.

Real-time simulation of cable pay-out and reel-in with towed fishing gears

Achieving real-time simulation of fast cable pay-out and reel-in manoeuvres with towed fishing gears is a challenging task. This work presents two new simulation methods based on simplified cable models for this kind of application. First, three numerical techniques are proposed to enhance a classical spring-based cable model, increasing its computational efficiency in manoeuvres that involve reeling the cable around a winch drum. Second, the development of an efficient multibody modelling approach based on natural coordinates is reported. The performance of these methods was assessed with two realistic examples. The numerical experiments involved different values of cable axial stiffness and spatial discretization levels, since these parameters were found to have a major impact on computational efficiency. The proposed methods achieved real-time performance in the simulation of systems modelled with up to a few thousand variables. Each modelling approach has advantages and limitations that must be considered when addressing a given application.

Maneuverability of <i>C<sub>b</sub></i>-Series Full Hull Ships

Maneuvering simulations for full hull ships were conducted by the MMG model, which is one of a maneuvering simulation method, based on the hydrodynamic force characteristics obtained in the captive model tests presented in previous paper1), and compared with the free-running model test results. The purpose of this study is to investigate the applicability of the MMG model to the full hull ships with very large block coefficient. We found that the original formula for longitudinal velocity component to rudder (uR) in the MMG model is not well working in case that the block coefficient (Cb) is very large as Cb = 0:87. To settle the problem, an improved formula of uR proposed by Yoshimura et al.3) was used and it was confirmed that the formula can capture the behavior of the rudder normal force just after steering better. Turning and course keeping performances in fullscale ships become worse comparing to those in ship model due to the worse rudder force performance comes from smaller propeller load in fullscale. Although the level of the worse turning performance is not so serious in fullscale, there is a possibility that overshoot angle of zig-zag maneuvers is over the IMO regulation for the present ship with Cb = 0.87.

Integration of ANCF continuum-based soil plasticity for off-road vehicle mobility in multibody system dynamics

In this paper, we outline the formulation and implementation of an inelastic continuum-based soil model in a multibody system (MBS) simulation environment. The generality of the approach allows for the simulation of general vehicle manoeuvres over unprepared terrain. Unlike other approaches, both the material and vehicle in this investigation can be altered independently. This ability allows for a greater degree of freedom in the design of computational models for the evaluation of off-road tracked vehicles. In this investigation, the soil model is developed using a hexahedral absolute nodal coordinate formulation (ANCF) finite element. The Drucker-Prager plastic material is used to model the behaviour of the soil and offers a good starting point for computational plasticity in terramechanics applications. A convergence study for a single link interacting with ANCF soil is provided. The capabilities and generality of this implementation is demonstrated using an armoured personnel carrier (APC) model.