Showing papers on "Rudder published in 2015"

Performance Enhancement of a Full-Scale Vertical Tail Model Equipped with Active Flow Control

Abstract: This paper describes wind tunnel test results from a joint NASA/Boeing research effort to advance active flow control (AFC) technology to enhance aerodynamic efficiency. A full-scale Boeing 757 vertical tail model equipped with sweeping jet actuators was tested at the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel (40x80) at NASA Ames Research Center. The model was tested at a nominal airspeed of 100 knots and across rudder deflections and sideslip angles that covered the vertical tail flight envelope. A successful demonstration of AFC-enhanced vertical tail technology was achieved. A 31- actuator configuration significantly increased side force (by greater than 20%) at a maximum rudder deflection of 30deg. The successful demonstration of this application has cleared the way for a flight demonstration on the Boeing 757 ecoDemonstrator in 2015.

Submarine Maneuvers Using Direct Overset Simulation of Appendages and Propeller and Coupled CFD/Potential Flow Propeller Solver

Abstract: This article presents two approaches to simulate maneuvers of a model radio-controlled submarine In the direct simulation approach, rudders, stern planes, and propellers are gridded and treated as moving objects using dynamic overset technology The second approach couples the overset computational fluid dynamics (CFD) solver and a potential flow propeller code, with both codes exchanging velocities at the propeller plane and wake, body forces, and propeller forces and moments, whereas rudders and stern planes are still explicitly resolved It is shown that during the maneuvers, the range of advance coefficients does not deviate much from the design point, making a coupled approach a valid choice for standard maneuvering simulations By allowing time steps about an order of magnitude larger than for the direct simulation approach, the coupled approach can run about five times faster The drawback is a loss of resolution in the wake as the direct propeller simulation can resolve blade vortical structures Open water propeller curves were simulated with both the direct propeller approach and the coupled approach, showing that the coupled approach can match the direct approach performance curves for a wide range of advance coefficients Simulations of a horizontal overshoot maneuver at two approach speeds were performed, as well as vertical overshoot and controlled turn maneuvers at high speed Results show that both CFD approaches can reproduce the experimental results for all parameters, with errors typically within 10%

Integrated Line of Sight and Model Predictive Control for Path Following and Roll Motion Control Using Rudder

Abstract: Roll motion control and path following are two representative marine control problems that have been traditionally treated separately. However, these two problems are closely coupled, as roll motion could cause negative effects on marine surface vessels during path following in seaways and path following actions could cause undesirable roll motion. In this article, an optimal controller is proposed for the integrated path following and roll motion control problem. The rudder, whose actuation amplitude and rate are both limited, is the only control input, while the cross-track error, heading angle, roll rate, and roll angle are the outputs that collectively define the performance of the system. This leads to a classic underactuated problem. Model predictive control is the natural choice for the solution, given its capability in dealing with constraints and multi-input‐multi-output system, and its design will be pursued in this article. Line of sight technique is used to extend the straight-line path following to arbitrary path following. A four degrees of freedom high-fidelity model is implemented as the simulation model, and the simulation results verify the effectiveness of the proposed controller. The influences of the control design parameters on system performance are investigated and the trade-offs between two key attributes, namely, the roll reduction and path following, are explored.

Aerodynamic Interference Issues in Aircraft Directional Control

Abstract: This work investigates the aerodynamic interference among airplane components caused by rudder deflection for a typical turboprop aircraft geometry through the computational fluid dynamics technique. At no sideslip, an airplane is in symmetric flight conditions. The rudder deflection creates a local sideslip angle close to the vertical tailplane, and this effect is increased by fuselage and horizontal tail. Typical semiempirical methods, such as United States Air Force Stability and Control Data Compendium (USAF DATCOM), do not take into account for these effects, proposing the same corrective parameters both for pure sideslip and rudder deflection conditions. Numerical analyses executed on several aircraft configurations with different wing and horizontal tailplane positions show that the interference factors are smaller than those predicted by the USAF DATCOM procedure, providing guidelines for a more accurate aircraft directional control analysis and hence rudder preliminary design.

Aircraft Turbulence Compensation Using Adaptive Multivariable Disturbance Rejection Techniques

Abstract: Dδe = aerodynamic drag derivative with respect to elevator deflection angle Lp, Np = roll and yaw moment derivatives with respect to roll rate Lr, Nr = roll and yaw moment derivatives with respect to yaw rate Lr, Lβ = aerodynamic roll moment derivative with respect to yaw rate and sideslip angle Lα, Dα, Tα = aerodynamic lift, drag, and thrust derivatives with respect to angle of attack L_ α = aerodynamic lift derivative with respect to rate of change angle of attack Lβ, Nβ = roll and yaw moment derivatives with respect to sideslip angle Lδe ,Mδe = aerodynamic roll and pitch moment derivatives with respect to elevator deflection angle L0, D0 = benchmark aerodynamic lift and drag derivatives with respect to angle of attack MV ,Mq = aerodynamic pitch moment derivative with respect to aircraft flight speed V and pitch rate Mα,M _ α = aerodynamic pitch moment derivative with respect to α and _ α m, g = mass of the aircraft, gravity acceleration Nδa, Lδa = yaw and roll moment derivatives with respect to aileron deflection angle Nδr, Lδr = yaw and roll moment derivatives with respect to rudder deflection angle p, q, r = body axis components of the angular velocity pW , qW , rW = local air mass angular velocities resulting from the wind gradients T, δT , TδT = engine thrust, throttle, and aerodynamic thrust derivative with respect to the throttle TV , DV , LV = thrust, aerodynamic drag, and aerodynamic lift derivatives with respect to airspeed V u; v; w uA; vA;wA = body axis components of VA uK, vK, wK = body axis components of VK V, VA, VK = airspeed (norm of VA), aircraft flight velocity, and aircraft track velocity VW ; uW , vW , wW = local turbulence velocity and body axis components of VW V0, α0, γ0 = benchmark flight velocity, angle of attack, and flight-path angle Yβ, Yp, Yr = side force derivatives with respect to sideslip angle, roll rate, yaw rate Yδa, Yδr = side force derivatives with respect to aileron deflection angle and rudder deflection angle α, β = angle of attack and sideslip angle αK , βK = angle of attack and sideslip angle due to VK αW , βW = angle of attack and sideslip angle due to VW θ, φ, ψ = Euler pitch, roll, and yaw angle σ = angle between thrust and body xb axis

Design, control, and implementation of a new AUV platform with a mass shifter mechanism

Abstract: This paper presents a design, control, and implementation of a new autonomous underwater vehicle (AUV) platform, which is designed as a torpedo shape with small and light enough to be handled easily by one person. Through a unique ducted propeller and rudder located at the aft, the AUV can perform horizontal motion. It can also control pitch angle and depth motion by an inside mass shifter mechanism (MSM) which changes the vehicle center of gravity. Hardware and software architectures of the control system are addressed and the functions of all parts are clarified. With a developed navigation algorithm, strategies for waypoint guidance, steering and diving controls are suggested. After that, a series of experiment results compared with the simulation outputs are presented.

A-TIRMA G2: An Oceanic Autonomous Sailboat

Abstract: This paper describes a new design of a 2 meter LOA (Length Over All) autonomous sailboat conceived for sailing in an ample set of weather conditions. The design has been focused on robustness and on achieving some degree of redundancy on critical components like sails and rudder. Accordingly, it is equipped with two light-weight carbon fiber wing sails and two slanted rudders protected by skegs. Its stability curve is fully positive, so she is capable of recovering autonomously from capsizing.

Study on manoeuverability and control of an autonomous Wave Adaptive Modular Vessel (WAM-V) for ocean observation

Abstract: In this paper, we are proposing the use of a catamaran equipped with standard navigational sensors as an autonomous surface vehicle for in situ measurement of oceanographic data or as a complimentary observing system. In this research, we mainly focus on the maneuverability of the Wave Adaptive Modular Vessel (WAM-V). The WAM-V must have ability to cruise on the water with a robust propulsion system which determines its propulsion capability and maneuverability. Firstly, the paper describes the configuration of WAM-V. Secondly the paper deals with mathematical modeling, which describes well physics based dynamics of WAM-V. Demand for WAM-V catamaran is justified to a point for improved manoeuverability and because the motion of the boat is affected by hydrodynamics, so many hydrodynamic parameters including resistance force for Mono hull and twin hull are estimated by towing tank experiment. It is observed from the experiments that at higher velocity (Froud Number (fn) > 0.3) due to interference between the two hulls the hydrodynamic derivatives do not remain same as in the case of a single hull. With the help of the geometrical shape of WAM-V the design ratios are calculated. The Matlab simulation is intended to analyze the different parameters for the effect of changing the propeller revolution which replaces the rudder action. Finally, the paper delineates the simulation results for PID tracking control of WAM-V using the Nomoto's response model.

Bionical underwater robot of flapping wing type

Abstract: The utility model discloses a bionical underwater robot of flapping wing type, including devil ray fish flat casing, the symmetry sets up the pectoral fin in devil ray fish flat casing both sides, rudder after locating in the middle of the devil ray fish flat casing lower extreme partially and the elevator of locating devil ray fish flat casing afterbody, the inside fish shape cavity that forms of devil ray fish flat casing, camera and sensor be equipped with in the head of fish shape cavity, the head that devil ray fish flat casing corresponds the camera is equipped with the aircraft bonnet of making a video recording, fish shape cavity belly is equipped with the battery, pectoral fin driving motor, the receiver, rudder face drive steering wheel, pectoral fin driving motor drives the pectoral fin luffing motion through four connecting rod transmission structure, rudder face drive steering wheel is connected with rudder and elevator respectively, be equipped with data acquisition interface in the elevator of devil ray fish flat casing afterbody. The utility model discloses bionical fish structural design adopts the pectoral fin to impel the mode, has high mobility to and the low noise, to environment disturbance advantage such as little, be applicable to among the underwater operation in fields such as military affairs and agricultural.

Hypersonic flight vehicle dive segment full amount integration guidance control method

Abstract: The invention provides a hypersonic flight vehicle dive segment full amount integration guidance control method. A technical scheme is characterized in that firstly, a sensor measures states of a hypersonic flight vehicle relative to a ground system, wherein the states comprise a speed, a speed inclination angle, a track yaw angle, a rolling angular speed, a yaw angular speed, a pitching angular speed, a pitch angle, a yaw angle, a rolling angle and the like; then the above obtained quantities of states, positional information of an object relative to the ground system and a control parameter are substituted into a formula so as to calculate a rudder deflection angle vector, wherein the positional information is measured in advance; finally, the rudder deflection angle vector is used to control the hypersonic flight vehicle. In the invention, based on an aircraft full amount coupling integration guidance control model, an adaptive-block dynamic surface inversion method is used to realize integrated guidance control, and a problem of repeated design can be effectively avoided so that time and economic cost of a guidance control system design are reduced.

Swarm intelligence applied to identification of nonlinear ship steering model

Abstract: The paper presents optimization of parameters of nonlinear dynamic ship steering model with one degree of freedom, in which the input is the commanded rudder angle and the output is the ship course. Optimization of parameters concerned the Bech and Wagner-Smith model for which the nonlinearity was determined from a standard Bech's reverse spiral test, whilst the parameters describing dynamic properties of the ship were determined based on the Kempf's zigzag maneuver. Optimal parameters of the searched ship model were found using swarm intelligence algorithms, including: ant colony optimization, artificial bee colony, and particle swarm optimization. Rate tests were conducted to find the optimal solution, and a comparative analysis of the results was made.

Sensitivity Study of Hydrodynamic Derivative Variations on the Maneuverability Prediction of a Container Ship

Abstract: The study of maneuverability of a ship involves the determination of the hydrodynamic derivatives in the equations of motion. The standard maneuvers are simulated by integrating the equations of motion and the maneuvering parameters are checked for compliance with appropriate standards set by IMO. The numerically or experimentally predicted hydrodynamic derivatives may differ from actual values of the built and operated ship. Hence, it is worth to understand the sensitivity of these variations on the actual maneuvering performance of the ship. This paper deals with a study on the sensitivity of the hydrodynamic derivatives in the equations of motion of a container ship (S175). The sensitivity analysis of all the hydrodynamic derivatives is performed by deviating each derivative in the range of −50% to +50% from the experimentally derived values, in steps of 10%. The standard maneuvering tests like turning tests at rudder angle, δ = 35° and 20°/20° zig-zag maneuvers are performed for each case and their effects on the standard maneuvering parameters are estimated. The hydrodynamic derivatives that are important and which have to be estimated with high level of accuracy in maneuvering studies for a container ship are identified through this study.Copyright © 2015 by ASME

Impacts of rudder profiles on ship manoeuvrability

Abstract: The performance of a ship’s rudder largely determines its manoeuvrability, which includes turning ability, initial turning ability, yaw-checking ability and course-keeping ability. However, existing empirical formulas for rudder forces do not concern the rudder profile. This paper discusses the impacts of various rudder profiles on ship manoeuvrability. Instead of empirical formulas for rudder characteristics, Computational Fluid Dynamic methods (CFD) are applied to obtain lift and drag coefficients of five profiles. Then, the normal force coefficient of each profile is calculated and corrected for the aspect ratio. Commercial packages Pointwise and ANSYS ICEM generate the unstructured and structured mesh, respectively. ANSYS Fluent solves the Navier-Stokes equations. 2D steady-state viscous simulations of rudders in incompressible water are carried out with the k-w SST turbulence model. To test the impacts on manoeuvrability, a manoeuvring model is built in Python for the KVLCC2 tanker in deep water. Turning circle manoeuvres and zigzag manoeuvres are performed to compare the manoeuvring parameters. This paper concludes with insights into the impacts of rudder profiles on ship manoeuvrability.

UDE based backstepping design for ship autopilot

Abstract: Designing autopilot for marine surface vessels poses challenging task as a ship is always under the influence of uncertainties which are of structured as well as unstructured in nature and external disturbances due to wave, wind, and ocean currents. In this work, to address the issues, a control strategy based on backstepping technique robustified by Uncertainty and Disturbance Estimator (UDE) is proposed. The design does not require any knowledge of bounds of uncertainties and disturbances and is able to effectively deal with the uncertainties and disturbances. It is shown by simulations how performance of autopilot is enhanced by combining these two methods in the presence of significant external disturbance. The limitation posed by rudder saturation and rudder rate is taken into consideration while designing the controller.

Model-based controller for ship track-keeping using neural network

Abstract: In the paper the Internal Model Control approach for ship autopilot system is presented. The proposed course controller employs the structure of the cascade system. The internal model of the plant and its inverse are estimated by neural network what made it possible to reduce the uncertainty of the control process. The ship model contains the saturation of the rudder angle and the rudder rate. Therefore to the controller design the structure with feedback connection is used. Computer simulation results are included in the paper to demonstrate the effectiveness of the proposed method.

Nonlinear Dynamic Modeling of a Fixed-Wing Unmanned Aerial Vehicle: a Case Study of Wulung

Abstract: Developing a nonlinear adaptive control system for a fixed-wing unmanned aerial vehicle (UAV) requires a mathematical representation of the system dynamics analytically as a set of differential equations in the form of a strict-feedback systems. This paper presents a method for modeling a nonlinear flight dynamics of the fixed-wing UAV of BPPT Wulung in any conditions of the flight altitude and airspeed for the first step into designing a nonlinear adaptive controller. The model was formed into 10-DOF differential equations in the form of strict-feedback systems which separates the terms of elevator, aileron, rudder and throttle from the model. The model simulation results show the behavior of the flight dynamics of the Wulung UAV and also prove the compliance with the actual flight test results.

Vehicular steering control device

Abstract: A vehicular steering control device 10 comprises a rudder angle variable device 14 which alters relationship between an operating position of a steering wheel 20 and an operating position of the steering wheel found from a rudder angle of steered wheels 18 FL and 18 FR, and a rudder angle control device 16 which performs an automatic steering control which controls the rudder angle of the steered wheels by controlling the rudder angle variable device. When a steering mode is switched from an automatic steering mode to a manual steering mode (S 150 ), the rudder angle control device gradually reduces a control gain Klka of the automatic steering mode (S 600 ), and reduces by degrees a size of a deviation between the two operating positions (S 400, 500, 800˜1000 ), only when the steering operation is performed by a driver (S 350 ).

AEOLUS, the ETH Autonomous Model Sailboat

Abstract: Path planning and control are particularly challenging tasks for a sailboat. In contrast to land vehicles or motorboats, the movement of a sailboat is heavily restricted by the wind direction. This paper focuses on the low-level control acting on the rudder and the sails. Specifically, a standard proportional controller and a non-linear controller have been implemented to track a reference heading. Further, special control algorithms that are activated during a tack or a jibe perform fast and smooth maneuvers. The path planner is based on the minimization of the weighted sum of different cost functions and allows for multi-objective optimization of the boat trajectory such as obstacle avoidance, time-to-target minimization and tactical behaviors.