Simulated Maneuvers Research Articles

Minimum Parameters Learning-Based Dynamic Surface Control for Advanced Aircraft at High Angle of Attack

Aiming at the difficulty of post-stall maneuvering control modeling and control of advanced aircraft under unsteady aerodynamics, a control method with high control accuracy and fast computation speed is proposed based on Radial Basis Function (RBF) network with minimum parameters learning (MPL) and dynamic surface control (DSC) method. Firstly, the aerodynamic characteristics of post-stall maneuvers are analyzed based on the experimental data of large-scale oscillation wind tunnels, and the key factors affecting the unsteady aerodynamic forces are obtained. Then, an accurate unsteady aerodynamic model is established based on the improved extreme learning machine (ELM) method. Secondly, the influence of unsteady aerodynamic forces on the control of post-stall maneuvers is considered. For the uncertainty of advanced aircraft model, high angle of attack flight control laws based on RBF-DSC are designed. In order to improve the calculation speed of the above control law and optimize the parameters, a post-stall maneuver control law method based on MPL-RBF-DSC is designed, and the stability of the method is proved. The coordinated allocation of the conventional aerodynamic surfaces and thrust vectors is realized based on the daisy chain method. Finally, the typical maneuver simulation of “Cobra” is carried out, which highlights the advantages of the design method in this paper, such as high control accuracy, short calculation time and strong robustness.

A Study on the Application of Sensitivity Analysis for Ship Hydrodynamic Coefficients

In the mathematical model with multiple input variables, the sensitivity analysis of the input variables is an important step to ensure the reliability of the mathematical model. In order to optimize the ship manoeuvring simulation, in particular the optimization of the trajectory ship, the sensitivity analysis should be performed in the mathematical model to select the group of the most sensitive hydrodynamic coefficients. In this paper, the author applied the sensitivity analysis method in mathematics model of ship manoeuvring programming in order to optimize the ship trajectory of Esso Bernicia 193000DWT tanker model.

A Study on Ship Manoeuvring Simulation and Ship Trajectory Optimization Based on Sqp and Bfgs Algorithms from Sea Trials

A Study on Ship Manoeuvring Simulation and Ship Trajectory Optimization Based on Sqp and Bfgs Algorithms from Sea Trials

A Frequency Domain-Based Sensitivity Study of a Submarine Manoeuvring Model

A frequency domain-based analysis of a submarine maneuvering model has been completed and used to study the effects of parameter uncertainty. The maneuvering model of the BB1-X submarine has been analyzed for the purpose of understanding the consequences of reduced input fidelity. Inputs were varied individually and ranked based on the resulting deviation from the original model. The model was also reduced to include fewer degrees of freedom or dynamic effects and compared with the original fully detailed model. The intention of this study is to determine which data are most crucial to the accurate maneuvering simulation of a submarine. Depending on the application of such a model, certain accuracies may be sacrificed to reduce resource requirements and save cost. The results of this study give some guidance as to which types of parametric data need to be the most detailed. Although the results will not give exact sensitivities for all submarine maneuvering models, it will give an indication of which areas should be focused on. 1. Introduction Producing a maneuvering model of a submarine must always be a balance between desired model fidelity and available resource and time. Depending on the purpose of a particular model, fidelity may be sacrificed in certain areas in the interests of reducing computational time or data input requirements. Before making this reduction, however, it is important to understand how various simplifications will affect the overall dynamic characteristics. If this is well understood, the process of creating models that are fit for purpose can be streamlined. The parametric data for a maneuvering model are often produced through experimental work or computational fluid dynamics (CFD) simulations. A certain amount of force and moment data can provide sufficient information to calculate a set of hydrodynamic coefficients which are used to populate a maneuvering model. The higher the data requirements, the longer these processes take. When reducing the extent of parametric data required, it is desirable to reduce detail in a manner which has minimal effect on the maneuvering model, and therefore, it is important to know which of the hydrodynamic coefficients are the most significant. For submarines, there is very little documented information about this in the open literature. An effort to describe the significance of some coefficients was first attempted by Ray et al. (2010). Ray provides an analysis of the hydrodynamic coefficients and their effect on a longitudinal zigzag maneuver. The analysis, however, focuses on eight coefficients and vertical plane motion only. The analysis in this report is significantly more comprehensive.

Time-Optimal Trajectory Planning along Parametric Polynomial Lane-Change Curves with Bounded Velocity and Acceleration: Simulations for a Unicycle Based on Numerical Integration

G2 lane-change path imposes symmetric conditions on the path geometric properties. This paper presents the comparative study of time-optimal velocities to minimize the time needed for traversal of three planar symmetric parametric polynomial lane-change paths followed by an autonomous vehicle, assuming that the neighboring lane is free. A simulated model based on unicycle that accounts for the acceleration and velocity bounds and is particularly simple for generating the time-optimal path parameterization of each lane-change path is adopted. We base the time-optimal trajectory simulations on numerical integration on a path basis under two different end conditions representing sufficient and restricted steering spaces with remarkable difference in allowable maximum curvature. The rest-to-rest lane-change maneuvering simulations highlight the effect of the most relevant path geometric properties on minimal travel time: a faster lane-change curve such as a quintic Bezier curve followed by a unicycle tends to be shorter in route length and lower in maximum curvature to have achievable highest speed at the maximum curvature points. The results have implications to path selection for parallel parking and allow the design of continuous acceleration profile via time scaling for smooth, faster motion along a given path. This could provide a reference for on-road lane-change trajectory planning along a given path other than parametric polynomials for significantly more complex, complete higher-dimensional highly nonlinear dynamic model of autonomous ground vehicle considering aerodynamic forces, tire and friction forces of tire-ground interaction, and terrain topology in real-world.

Integrated vehicle chassis control for active front steering and direct yaw moment control based on hierarchical structure

This paper presents an integrated vehicle chassis control (IVCC) strategy to improve vehicle handling and stability by coordinating active front steering (AFS) and direct yaw moment control (DYC) in a hierarchical way. In high-level control, the corrective yaw moment is calculated by the fast terminal sliding mode control (FTSMC) method, which may improve the transient response of the system, and a non-linear disturbance observer (NDO) is used to estimate and compensate for the model uncertainty and external disturbance to suppress the chattering of FTSMC. In low-level control, the null-space-based control reallocation method and inverse tyre model are utilized to transform the corrective yaw moment to the desired longitudinal slips and the steer angle increment of front wheels by considering the constraints of actuators and friction ellipse of each wheel. Finally, the performance of the proposed control strategy is verified through simulations of various manoeuvres based on vehicle dynamic software CarSim.

Modeling and Maneuverability Simulation for Vertical Plane of Autonomous Underwater Vehicle in Current

As the large diving depth Autonomous underwater vehicle (AUV) developed, modeling and maneuverability simulation for AUV in vertical plane under current disturbance are increasingly important. The REMUS model is adopted to build the mathematical model of AUV. The observation data of the current in South China Sea are analysed to build the current model varied with depth, then the relative motion method is adopted to build the model of AUV in current. The simulation system of maneuverability is established with MFC and some simulation experiments including without current and in current are carried out. The results show that the motion of AUV can be well simulated and some suggestions are given for vertical plane control of AUV.

Steering Stability Control for a Four Hub-Motor Independent-Drive Electric Vehicle with Varying Adhesion Coefficient

In order to enhance the steering stability of a four hub-motor independent-drive electric vehicle (4MIDEV) on a road with varying adhesion coefficient, for example on a joint road, this paper proposes a hierarchical steering stability control strategy adapted to the road adhesion. The upper control level of the proposed strategy realizes the integrated control of the sideslip angle and yaw rate in the direct yaw moment control (DYC), where the influences of the road adhesion and sideslip angle are both studied by the fuzzy control. The lower control level employs a weight-based optimal torque distribution algorithm in which weight factors for each motor torque are designed to accommodate different adhesion of each wheel. The proposed stability control strategy was validated in a co-simulation of the Carsim and Matlab/Simulink platforms. The results of double-lane-change maneuver simulations under different conditions indicate that the proposed strategy can effectively achieve robustness to changes in the adhesion coefficient and improve the steering stability of the 4MIDEV.

Determination of Minimum Distance to Obstacle Avoidance in the Singapore Strait

In the maritime simulation models of obstacle avoidance, the parameter of critical contact closest point of approach (CCPA) is defined as the minimum safe distance to avoid an obstacle contact. Although the parameter of CCPA plays a decisive role on the maneuvering of the ship for obstacle avoidance, it is generally set with an uncalibrated input value in many obstacle avoidance simulation models. This study focuses on the parameter calibration of the critical CCPA by utilizing the automatic identification system (AIS) data in the Singapore Strait and maneuver simulation experiments. First, an effective mathematical method is proposed to identify ship obstacle avoidance from the big AIS data. Together with several obstacles and the AIS data in the Singapore Strait, the average critical CCPA values are identified for different ship classes. Second, a series of maneuver simulation experiments on Dalian Maritime University navigational simulators are conducted by professional captains. Based on the experimental data, the simulation-based critical CCPA values are derived. Finally, these calibrated CCPA values from the above two methods are compared and analysed. The comparison result implies that these critical CCPA values, derived from AIS data and maneuver simulators, are matched and confirm the rationality of one another. It also reveals that the average critical CCPA value for each ship class has an increasing trend with the increased ship length.

Adaptive backstepping sliding mode control for wheel slip tracking of vehicle with uncertainty observer

The wheel slip tracking control is the basis of automatic braking control systems, and the accurate tracking for the desired wheel slip in the presence of lumped uncertainty is a vital guarantee of automatic braking control systems reliable operation. Therefore, an adaptive backstepping sliding mode control approach with radial basis function neural network is proposed to design the nonlinear robust wheel slip controller based on a quarter-vehicle model with lumped uncertainty. The radial basis function neural network as the uncertainty observer can effectively reduce the chattering of sliding mode by estimating the lumped uncertainty, and the adaptive law for the unknown weight vector of radial basis function neural network is derived by Lyapunov-based method. The influence of changes in tire sideslip angle and camber angle on the tire -road friction coefficient acts as an unknown scaling factor, and the adaptive law for the unknown scaling factor is derived via Lyapunov-based method. Then, the performance of the proposed controller is verified through simulations of various maneuvers on a full-vehicle dynamics simulation software.

Improvement of maneuverability in a VLCC by a high lift rudder

In this study, the improvement of maneuverability of a Very Large Crude oil Carrier (VLCC) with small engine output under a condition involving 30% reduced EEDI [IMO (2012)] was performed by attaching a high lift rudder. A high lift rudder (HL rudder) with a fishtail section and end plates was newly designed to increase the rudder force under a restriction that minimizes the increase in rudder resistance. Tank tests were performed by using a scaled ship model with a HL rudder to capture propulsive performance and rudder force characteristics of the ship with a HL rudder. The results indicated that the designed HL rudder increased the effective rudder force by approximately 10% when compared to a conventional mariner rudder (MN rudder). The incorporation of the test results into the MMG simulation model [Yasukawa and Yoshimura (2015a)] allowed the performance of maneuvering simulations in calm water and adverse weather conditions for a ship with HL and MN rudders. The results indicated that the HL rudder presented in this study is useful in improving maneuverability while maintaining almost the same level as the propulsive performance of a ship with a mariner rudder.

Modeling and trajectory tracking control of a two-wheeled mobile robot: Gibbs–Appell and prediction-based approaches

SUMMARYThis study deals with the problem of trajectory tracking of wheeled mobile robots (WMR's) under non-holonomic constraints and in the presence of model uncertainties. To solve this problem, the kinematic and dynamic models of a WMR are first derived by applying the recursive Gibbs–Appell method. Then, new kinematics- and dynamics-based multivariable controllers are analytically developed by using the predictive control approach. The control laws are optimally derived by minimizing a pointwise quadratic cost function for the predicted tracking errors of the WMR. The main feature of the obtained closed-form control laws is that online optimization is not needed for their implementation. The prediction time, as a free parameter in the control laws, makes it possible to achieve a compromise between tracking accuracy and implementable control inputs. Finally, the performance of the proposed controller is compared with that of a sliding mode controller, reported in the literature, through simulations of some trajectory tracking maneuvers.

International benchmark study on numerical simulation methods for prediction of manoeuvrability of ships in waves

The paper summarizes the results of the SHOPERA international benchmark study of numerical methods for the prediction of time-average wave-induced forces and manoeuvres of ships in waves. These topics are of paramount importance for both the scientific community and the maritime industry in view of the recently introduced international regulations concerning manoeuvrability of ships in adverse conditions. Benchmarked numerical methods, ranging from semi-empirical formulae and potential flow methods to Reynolds-averaged Navier-Stokes solvers, were applied in a comparative way to a series of specified test cases and compared with experimental data to conclude on the present international state of the art in the study field. Whereas several numerical methods could predict accurately the time-average wave-induced forces, none of them provided sufficiently accurate results throughout all test cases, thus their application in design and approval needs validation in each individual case. Regarding direct numerical simulations of manoeuvres in waves, the study showed their immature state for practical design and approval. These outcomes, attributed to a great extent to the complexity of the problem and specifications both for numerical simulations and model tests, necessitate additional numerical and experimental studies to clarify identified critical issues and thus improve the capability of numerical tools.

Envelope oriented singularity robust steering law of control moment gyros for spacecraft attitude maneuver

The problem of steering pyramid control moment gyro (CMG) cluster for fast spacecraft attitude maneuver along eigenaxis is investigated. A novel steering law is proposed to continuously attempt to reduce the difference between the current gimbal angle and the desired one corresponding to the angular momentum envelop of the CMG cluster. The proposed steering law can be decomposed into two parts: the first one is a singularity robust term to keep maneuverability and produce control torque, and the other is a null motion term to rearrange the gimbal angles toward momentum envelope. By involving this steering law, it is expected to possess both rapid angular momentum exchange and singularity avoidance ability. In addition, by introducing a new limit vector on attitude error, classical cascade-saturation control algorithm is revised to guarantee spacecraft eigenaxis rotation. Both open-loop steering law test and closed-loop attitude maneuver simulations are performed to evaluate the efficacy of the proposed methods.

Time-domain simulator for short-term ship manoeuvring prediction: development and applications

ABSTRACTThis paper presents a short-term time-domain algorithm for ship motion simulation. Plane motion was considered, and thus, a three degrees of freedom model was used. The main inputs of the model are: propellers speed, rudder angles and initial conditions (initial position/orientation and linear/rotational velocity). The outputs are final ship position and orientation after a given simulation time. The data available in the Voyage Data Recorder and the results of sea trials performed before the ship delivery were used to estimate the needed parameters, implementing a simple but reliable linear regression scheme. The proposed model was applied to Costa Concordia manoeuvring simulation in order to assess its reliability in terms of trajectory prediction. Finally, as an example of application, the simulator was implemented in a real-time manoeuvring predictor, which is capable of foreseeing the ship position up to 40 s ahead in time, supporting the Commander in emergency operations.

Longitudinal Motion Due to Action of Tunnel Thrusters

Abstract Tunnel thrusters are propulsion and active control devises that provide a side force, or transverse thrust, to support mooring operations or position keeping. They shorten the time of manoeuvring, reduce the cost of towage and since inception, manoeuvrability specifically in ports has become a lot easier. Tunnel thrusters can either be operated manually or with the help of Dynamic Positioning systems which makes it even more efficient. Theoretically, the transverse force due to tunnel thruster action should generate only lateral and rotational motion. Therefore, it is typical and a common practice during manoeuvring simulations that the longitudinal motion due to the action of tunnel thrusters is neglected. Nevertheless, the experience of masters and pilots shows that some longitudinal motion due to the action of tunnel thrusters appears. This paper shows some examples of turning manoeuvres carried out with bow thrusters only, i.e. no additional control devices or tug assistance have been used. The manoeuvres have been carried with minimal possible initial longitudinal nor lateral speed. Model tests have been done with the use of large manned models of VLCS, PCTC and LNG carrier, which differ in hull shape, dimensions and shape coefficients. Results obtained from the tests confirm that the motion caused by bow thruster besides rotational and lateral motion consists additionally of longitudinal motion. Analysis of the combination of motions due to the action of tunnel thrusters have been done and some rationale for this phenomenon has been presented. Additionally a short analysis of position of pivot point during tunnel thruster test has been carried out.

파랑 표류력을 고려한 선박의 파랑 중 선회성능 해석

This paper performs a numerical computation of ship maneuvering performance in waves. For this purpose, modular-type model (MMG (Mathematical Modeling Group) model) is adopted for maneuvering simulation and wave drift force is included in the equation of maneuvering motion. In order to compute wave drift force, two different seakeeping programs are used: AdFLOW based on Wave Green function method and SWAN based on Rankine panel method. When wave drift force is calculated using SWAN program, not only ship forward speed but also ship lateral speed are considered. By doing this, effects of lateral speed on wave drift force and maneuvering performance in waves are confirmed. The developed method is validated by comparing turning test results in regular waves with existing experimental data. Sensitivities of wave drift force on maneuvering performance are, also, checked.

Dynamic maneuver loads calculations for a sailplane and comparison with flight test

This work presents the results of dynamic maneuver simulations of a sailplane and the comparison with flight test data. The goal of the effort is to extend and validate an in-house toolbox used for loads analysis of free-flying flexible aircraft in the time domain. The underlying aerodynamic theories are the steady vortex lattice and the doublet lattice method with a rational function approximation for the unsteady simulations in the time domain. The structural model comprises a beam model to represent the stiffness properties and a lumped mass model, both are developed using preliminary design methods. Steady aeroelastic trim simulations are performed and used as initial condition for the time simulation of the unsteady maneuvers in which the pilot’s commands, which were recorded during flight test, are prescribed at the control surfaces. Two vertical maneuvers with elevator excitation, two rolling maneuvers with aileron excitation and three aileron sweeps are simulated. The validation focuses on the comparison of interesting quantities such as section loads, structural accelerations and the rigid body motion. Good agreement between simulation and flight test data is demonstrated for all three kinds of maneuvers, confirming the quality of the models developed by the preliminary design methods.

Modeling and performance analysis of a vehicle with kinetic dynamic suspension system

This paper presents a kinetic dynamic suspension (KDS) system to achieve enhanced cooperative control of the roll and warp motion modes for on-road and off-road sports utility vehicles (SUV). The proposed KDS system consists of two hydraulic circuits acting on two pairs of torsional rods and levers, which can be treated as novel anti-roll bars. Hence, these anti-roll bars do not work independently, but are coupled to merely respond to particular motion modes. To verify the handling and ride performance of the system, a 14-DOF model of a SUV and a “magic formula” tire model are developed. The dynamic responses of the vehicle model with KDS suspension are obtained through half-sine bump, asynchronous sine road, and fishhook maneuver simulations. The responses of the KDS equipped vehicle are compared to those of one with anti-roll bars to demonstrate its improved performance and also illustrate the side-effects. The results show that the KDS system considerably improves the vehicle’s anti-roll ability. Furthermore, the vehicle’s warp stiffness is significantly reduced by the KDS system, which enhances the vertical load distribution of each wheel when driving off-road.

Six-DOF simulations of an underwater vehicle undergoing straight line and steady turning manoeuvres

This paper reports on numerical simulations conducted on an underwater vehicle for six-degrees of freedom (6-DOF) free running manoeuvres using Computational Fluid Dynamics (CFD). The CFD manoeuvring trials (straight line and steady turning manoeuvres) were conducted using a model-scaled BB2 submarine with movable control planes and a body force propeller represented by an actuator disk incorporating predetermined propulsion properties. The propulsion properties were obtained from captive self-propulsion simulation adopting the actual BB2 propeller. The free running simulations were validated against experimental data. The results showed that the 6-DOF CFD simulations are capable of predicting the BB2 manoeuvring characteristics with good agreement against the experimental data. The 6-DOF manoeuvring simulations carried out allow for the unsteady viscosity effects, which is usually a limitation of the traditional coefficient-based prediction method. The simulations will enable accurate determination of the vehicle's manoeuvring characteristics, which are essential for the control system design and its safe operating envelope.