Maneuver Prediction Research Articles

구속모형시험을 이용한 KCS 선형의 조종성능 추정

Recently, ultra large scale of ship is being ordered continuously and because of that, the accurate prediction of ship maneuverability in design stage becomes important matter. The model test like PMM test or CFD analysis are representative methods for predicting the maneuverability of ship. In this study, the captive model tests were carried out for predicting maneuverability of MOERI container ship(KCS) which is opened to the public using X-Y Carriage of Ocean Engineering Wide Tank of University of Ulsan. Considering the dimensions of tank, 2m class model ship was used for captive model test. CMT(Circular Motion Test) was performed for obtaining purer hydrodynamic coefficients related to yawing velocity. For getting hydrodynamic coefficients which cannot be obtained using CMT, PMM test(Planar Motion Mechanism test) were also performed. The maneuverability prediction results by simulation are compared with those of other research institutes.

KCS 선형의 4자유도 조종성능 추정

This paper presents the results of prediction of maneuverability of KCS about 4 degree of freedom(DOF) including roll motion. The prediction is carried out by CPMC captive model test. The CPMC(Computerized Planar Motion Carriage) with captive model test equipment including roll moment gage is installed at Ocean Engineering Tank of MOERI. KCS is the container ship open to the world by MOERI. To predict the 4 DOF maneuverability of a ship some tests with roll angle are conducted. And the prediction results of maneuverability by simulation are compared with the results of free running model test. The simulation results agree well with those of free running model tests.

A Sub-idle Compressor Characteristic Generation Method With Enhanced Physical Background

Sub-idle is a very challenging operating region as the performance of a gas turbine engine changes significantly compared with design conditions. In addition, the regulations for new and existing engines are becoming stricter and the prediction of engine relight capability is essential. In order to predict the performance of an engine, detailed component maps are required. The data obtained from rig tests are insufficient at low speeds, creating the need for generation of maps within the sub-idle regime. The first step toward this direction is the use of an extrapolation process. This is a purely mathematical process and the results are not usually of sufficient accuracy. In addition, this method does not provide any insight on the physical phenomena governing the operation of the compressor at low speeds. The accuracy of the resulting compressor map can be increased with a better low speed region definition; this can be achieved via the thorough study of a locked rotor compressor, enabling the derivation of the zero rotational speed line and allowing an interpolation process for the generation of the low speed part of the characteristic. In this work, an enhanced sub-idle compressor map generation technique is proposed. The suggested methodology enables the generation of characteristics at far off-design conditions with enhanced physical background. Alternative parameters for map representation are also introduced. Provided that the all the blade rows of the compressor are of known geometry, a numerical analysis is used for the calculation of the characteristic of the half stage and a stage stacking method is employed to create the entire compressor characteristic. This way, the sub-idle region of the map can be calculated through interpolation, which provides a more accurate and predictive technique. Application of the method for compressor map generation showed that the proposed interpolation approach is robust and capable of enhancing any performance simulation tool used for the prediction of transient altitude relight or ground-starting maneuvers.

Hydrodynamic Force Database with Medium High Speed Merchant Ships Including Fishing Vessels and Investigation into a Manoeuvring Prediction Method

Hydrodynamic Force Database with Medium High Speed Merchant Ships Including Fishing Vessels and Investigation into a Manoeuvring Prediction Method

Maneuver prediction for road vehicles based on a novel neuro-fuzzy dynamic architecture

Collision avoidance systems for road vehicles may benefit from timely predictions of vehicle maneuvers. This article presents a novel approach for the prediction of maneuvers that copes with noisy measurements and is based on a supervised version of a dynamic FasArt method (SdFasArt). Additionally, the use of size-dependent scatter matrices to compute the activation of the neurons makes the algorithm more adaptable to different data distributions. The results obtained in real tests confirm the goodness of the method.

Maneuver Prediction for Road Vehicles Based on a Neuro-Fuzzy Architecture With a Low-Cost Navigation Unit

Collision avoidance is currently one of the main research areas in road intelligent transportation systems. Among the different possibilities available in the literature, the prediction of abrupt maneuvers has been shown to be useful in reducing the possibility of collisions. A supervised version of dynamic Fuzzy Adaptive System ART-based (dFasArt), which is a neuronal-architecture-based method that employs dynamic activation functions determined by fuzzy sets, is used for maneuver predicting and solving the problem of intervehicle collisions on roads. In this paper, it is shown how the dynamic character of dFasArt minimizes problems caused by noise in the sensors and provides stability on the predicted maneuvers. Several experiments with real data were carried out, and the SdFasArt results were compared with those achieved by an implementation of the Incremental Hierarchical Discriminant Regression (IHDR)-based method, showing the suitability of SdFasArt for maneuver prediction of road vehicles.

Collision avoidance support in roads with lateral and longitudinal maneuver prediction by fusing GPS/IMU and digital maps

Collision avoidance in roads can be addressed in several ways, being cooperative systems one of the most promising options. In cooperative collision avoidance support systems (CCASS) the vehicles which constitute a scene share by means of communication links information that can be useful to detect a potentially risky situation. Typically, this information describes the kinematic state of each vehicle and can be complemented with a prediction of its next state. Indeed, the timely prediction of the next maneuver of a vehicle results beneficial to estimate the risk factor of a scene. This article presents a solution to the problem of maneuver prediction which employs a reduced number of sensors: a Global Navigation Satellite System (GNSS) receiver, one gyro, one accelerometer and the odometry. Predictions are made by a bi-dimensional interactive multiple model (2D-IMM) filter in which longitudinal and lateral motions of the vehicle are distinguished and maneuvering states are described by different kinematic models. A number of experiments were carried out with two vehicle prototypes in several circuits. The results achieved prove the suitability of the proposed method for the problem under consideration.

CPMC 구속모형시험에 의한 KCS 선형의 조종성능 추정

This paper presents the results of prediction of maneuverability of KCS by CPMC captive model test. The CPMC(Computerized Planar Motion Carriage) with captive model test equipment is installed at Ocean Engineering Tank of MOERI. KCS is the container ship which was open to the world by MOERI. And the test results for the prediction of maneuverability were presented by NMRI in Japan. The research results about the maneuverability of KCS were presented at SIMMAN 2008 Workshop in Denmark. The results of test and simulation of this paper are compared with the results of simulation by MOERI using test results of NMRI and simulation results by NMRI.

Application of support vector machine to ship steering

System identification is an effective way for modeling ship manoeuvring motion and ship manoeuvrability prediction. Support vector machine is proposed to identify the manoeuvring indices in four different response models of ship steering motion, including the first order linear, the first order nonlinear, the second order linear and the second order nonlinear models. Predictions of manoeuvres including trained samples by using the identified parameters are compared with the results of free-running model tests. It is discussed that the different four categories are consistent with each other both analytically and numerically. The generalization of the identified model is verified by predicting different untrained manoeuvres. The simulations and comparisons demonstrate the validity of the proposed method.

A desktop ship manoeuvrability prediction system

This paper presents low-cost, reasonable accurate system for model design factors influencing a ship's manoeuvrability. The presented system is based on modified Abkowitz's mathematical model, with both linear and non-linear differential equations.

Sensitivity analysis of submersibles’ manoeuvrability and its application to the design of actuator inputs

The influences of hydrodynamic coefficients on the prediction of manoeuvrability were examined by sensitivity analysis (SA) of direct method. The equations of motion used were the standard equations of motion for submarine [Gertler, M., Hagen, G.R., 1967. Standard equations of motion for submarine simulation. DTNSRDC Report], and three submersibles with different appendages were considered. Numerical simulations of three types of sea trials are performed to obtain the sensitivities of motions to hydrodynamic coefficients. Since the accuracy of hydrodynamic coefficients’ estimates is increased by the use of sensitivity-maximizing inputs, the sensitivity-optimal actuator commands that are sequences of bang-bang type inputs were deduced with genetic algorithm (GA) optimization technique.

수중운동체의 조종성능에 대한 민감도 해석법의 적용

Sensitivity Analysis(SA) is used to predict how the model response varies according to changes in the model parameters. With SA, confidences in models which are developed to approximate certain processes and their predictions can be increased. The influences of hydrodynamic coefficients on the prediction of manoeuvrability are examined by SA of direct method. The equations of motion used are the standard equations of motion for submarine(Gertler 1967), and submerged bodies with three different appendages are considered. Through numerical simulations of three kinds of sea trials, the sensitivities of motions to hydrodynamic coefficients are found. Changes of sensitivities during trials are found to be highly dependent on the actuator scenarios and geometry of submerged body.

선박 조종성능 연구를 위한 선체형상 파라메터와 유체력미계수와의 관계분석

이 연구는 선박 설계 초기단계에서 선형 변화에 따른 선박 조종성능 추정에 관한 내용을 다루었다. 선박제원을 대표하는 파라메터 그리고 선미형상의 변화를 민감하게 반영할 수 있는 새로운 파라메터를 선정하는 작업을 수행하였다. 이렇게 선정된 파라메터와 유체력 미계수와의 상관관계를 알아보기 위하여 구속모형 실험을 수행하였다. 그 결과 기본적인 선박제원 중 선체 유체력 미계수와 상관도가 높은 파라메터를 가려낼 수 있었다. 또한 선미형상의 새로운 파라메터와 조종성능과의 상관도를 추정할 수 있었다. 또한 이를 활용하여 유체력미계수에 대한 새로운 경험식을 제시하였다. 이를 활용하면, 초기 선형 설계 시 선형변화 및 수정에 따른 조종성능 추정에 활용할 수 있을 것으로 판단된다. This study was carried out to examine the prediction of ship's manoeuvrability in initial design stage. New parameter representing basic hull form and stem shape were proposed. Captive model test were carried out to investigate the correlation coefficient between hydrodynamic coefficient and hull parameter. The results showed which parameter are positive correlation with hydrodynamic coefficient. Moreover correlation was examined between stem hull shape and ship's manoeuvrability. New empirical formulas for hydrodynamic coefficients were proposed These results can be used to predict a ship's manoeuvrability in initial design stage.

측벽근방을 항해하는 대형선박에 미치는 측벽의 영향

측벽과 선박간의 상호 간섭력이 선박 조종 운동에 상당히 크게 작용하는 것은 잘 알려셔 있다. 이 논문에서 측벽 부근을 항해하는 선박에 미치는 측벽의 간섭 영향에 대해서 다루어지고, 선박과 측벽간의 간섭력 추정을 위해 세장체 이론을 토대로 학 계산 방법이 적용되며, 선박 조종 운동에 미치는 측벽의 영향을 파악하기 위하여 선박과 돌제(반원)형상을 하고 있는 측벽간의 간섭력을 수치 계산하였다. 이 논문에서 사용되어진 계산 방법은 제한수역에서의 충돌 회피를 위한 선박의 자동 세어 시스템과 해상 교통 제어 시스템 및 항만 건설 등을 위한 초기 설계 단계에서 선박 조종성의 예측에 상당히 유용할 것이다 It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motion This paper deals with the interaction effect acting on a ship navigating closely in the proximity of bank wall. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wall is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wall are predicted to evaluate an influence of these interaction forces on ship manoeuvrability. The calculation method used in this paper will be useful for prediction of ship manoeuvrability at the initial stage of design, for automatic control system of ship in confined waterways, for discussion of marine traffic control system and for construction of harbour.

측벽부근을 항해하는 선박과 측벽간의 상호 간섭력에 관한 연구

It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motions. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wall is investigated. The numerical simulations on hydrodynamic interaction force acting on a ship in the proximity of bank wall are carried out by using this theoretical method. The theoretical method used in this paper will be useful for practical prediction of ship manoeuvrability at the initial stage of design, for discussion of marine traffic control system and for automatic control system of ship in confined waterways.

From Water Tunnel to Poststall Flight Simulation: The F/A-18 Investigation

Introduction T HE prediction of poststall maneuvers and departure characteristics of high-performance aircraft continues to be challenging,1;2 due, in particular, to the highly three-dimensional nature of the motions and aerodynamic responses. A case in point is the F/A-18 aircraft (Fig. 1), which has experienced departures from controlled  ight, typically involving large sideslip excursions with attendant high body-axes rate variations leading to high angles of attack ® (Ref. 4). The lateral–directional departure susceptibility of the F/A-18 provided part of the motivation within the NASA High-Alpha Technology Program for the improvement of high-alpha predictionsbased on ground testing. The gyrations and responsesexperiencedon departureare intrinsicallynonplanar, that is, involvingarbitraryrotationsnot alignedwith theprincipalaxesof the aircraft.3 When the  ight mechanical deŽ ciencies of an F/A-18 simulation were identiŽ ed, a Canadian programwas undertaken to enhance simulator Ž delity.6 The areas in which the airframe model could be improved included the poststall aerodynamicdatabase, the multivariabletable lookuparchitecture,and the aerodynamicmodel. The present paper focuses on the improvements to the database. The shortcomings of the poststall aerodynamic database were attributed largely to facility interference and scaling effects not accounted for and gaps in the parameter space covered. The original rotary database for F/A-18 was generated in the NASA Langley Research Center Spin Tunnel.11 The F/A-18 poststall maneuvering aerodynamics is dominated by forebody/leading edge extension (LEX) vortex interactions at moderately high angles of attack (30 55 deg). In the light of the sensitivity of the vortex interactions to sideslip angle (Ref. 12), it was deemed necessary to generate a more detailed rotary database to deŽ ne the associated relationshipsover a large sideslip range. When the advantages of the water-tunnel approachwere considered, it seemed appropriate to use this ground-testmethodology to generate supplementary data. The orbital platform rotary balance system (OPLEC) at the Institute for Aerospace Research (IAR) water tunnel, a diagnostic tool for studying support interference7;8 and unsteady wall interference, was subsequently used in highresolution tests as well as diagnostic experiments15i18 on the baseline F/A-18. A thorough understanding of scale effects on vortex

Artificial Neural Networks

Computation of ship maneuverability using ANN is based on ANN's nonlinear mapping function to perform the project from ship particular space to ship maneuverability space. It is more flexible to some extent to select input particulars and convenient to be used in ship design. BP(Back Propagation) networks and the neuron function are used in this paper. The learning algorithm is gradient descending combined with momentum factor. The sample data were condensed to 0. 1-0. 9 in advance. According to the result of 9 various ships' computation, the RMS is 0. 6137. Furthermore, 9 bulk ships are selected for ship's maneuverability prediction. After 12, 000 times training based on data of turning test of 8 bulk ships, the relative prediction precision of turning test of the 9th bulk ship is - 7. 16% (advance), 7. 16 % (transfer) and 0. 03% (tactical diameter).

Manoeuvring Performance of the Fishing Boat Modified by a Bulge

Fishing boats suffer from much capsizing as compared with other vessels. It may be pointed out that the stability of fishing boats tend to be poor as the bases of the severe operations and the poor management of loading condition as well as the problem with the restrictions of principal dimensions of ship. According to the recent capsizing of the trawler “Ryuho-maru V”, Ministry of Land, In-frastructure and Transport of Japan forced to check the stability of existing fishing boats and to improve the stability if not enough.As for the improvement of the stability, the fitting of a bulge on sidewall of the vessel is one of the best solutions. This method was adopted in the old naval fleets and polar research ship “Sohya” in Japan. However, it is not commonly used. It is important to clarify for the design of the bulge what influence it has on the ship's performances not only on the stability.In this paper, the authors have investigated into the effect of the bulge on manoeuvrability and the manoeuvring prediction, based on the model experiments and the full-scale experiments of original and enlarged fisheries research ship “Ushio-maru”. They have also investigated into the predicting method for a fishtail type high-lift rudder is proposed.The concluding remarks are summarized as below.(1) By fitting the bulge on sidewalls of the vessel, hydrodynamic sway damping lever is slightly reduced. In addition, the yaw damping lever is reduced by the increase of ship's mass, which keeps the almost the same stability lever of course keeping as the original ship.(2) For the prediction of the hydrodynamic derivatives of the fishing boat with an initial trim, Kijima's formula are useful except Y'β, N'r, Y'r-m'x, using the effective draught and block coefficient of the ship. It is desirable that Y'β, N'r, Y'r-m'x are not corrected by the initial trim.(3) For the simulation of the manoeuvring ship motion with the fishtail type high-lift rudder, the rudder open characteristic is to be altered in the proposed mathematical model. The coefficient becomes 1.4 times larger than the conventional rudder. Even for the large rudder angle such as 65°, the conventional rudder model is still available, because the actual angle of attack is decreased by the turning motion of ship.

A Numerical Study on Hydrodynamic Interaction between Oblique Ship Hull and Rudder

The result of the previous validation study has shown a significant error especially for the prediction of course stability of an unstable ship. To improve the accuracy of the prediction, it will be required to estimate high accuracy hydrodynamic interaction among ship hull, propeller and rudder as well as hydrodynamic forces acting on a bare hull taking account of the detailed ship form such as stern profile and frame line.This paper describes a study on the application of CFD (Computational Fluid Dynamics) to ship's manoeuvrability prediction at design stage. A numerical method has been applied to compute flows around a ship with a rudder in several oblique motions. Calculated interaction forces between ship hull and rudder are compared with measured ones. From this study, it is found that this hydrodynamic approach would be useful for prediction of ship manoeuvring motion

Concept of a Modem Manoeuvre Prediction System for Ships

Due to more largely becoming ship units its manoeuvring freedom in enveloped sea areas is limited. Therefore a more exact knowledge of the sea area conditions and variable disturbances in the zone of manoeuvre than with smaller ship units is necessary. The on-board sensor technology can determine only the body-related variable disturbances. By using of an external acoustic doppler current profiler (ADCP) in connection with a telemetry mechanism and an up-to-date identified ship's model the calculation results of the manoeuvre predictor should be improved. The harbour approach Puttgarden will be the example area for the investigations.