Maneuverability Index Research Articles

Maneuverability indices estimation of nonlinear response model based on full-scale trial data and square root unscented Kalman filter

Research on ship maneuvering performance provides a theoretical reference for autonomous ship navigation control. The gain and time coefficients accurately describe the dynamic performance of the ship. Given the challenge that the unscented Kalman filter cannot ensure the nonnegativity of the state covariance matrix during the filtering process, this study proposed a parameter identification scheme for a second-order nonlinear response model based on the square root unscented Kalman filter. First, the maneuverability indices of the free-running model were identified based on simulation data. Thereafter, the feasibility and convergence performance of the proposed scheme were verified. Based on full-scale trial data with uncertainty interference, the parameters of the second-order nonlinear response model were estimated for the YUKUN ship. The feasibility, effectiveness, and generalizability of the proposed scheme were further verified. The proposed scheme was analyzed based on three perspectives: parameter convergence, estimation results of the maneuverability indices, and yaw angle prediction results. The results obtained using the proposed algorithm were compared with those obtained using the extended Kalman filter. Finally, the proposed scheme can provide a reference for online parameter identification and prior knowledge for course keeping controllers and autonomous navigation control.

MSE Design of Nearly Constant Velocity Kalman Filters for Tracking Targets With Deterministic Maneuvers

When tracking maneuvering targets with a nearly constant velocity (NCV) Kalman filter with white noise acceleration, the selection of the process noise variance is complicated by the fact that the process noise errors are modeled as white Gaussian in the Kalman filter, while target maneuvers are deterministic or highly correlated in time. In recent years, the deterministic maneuver index was introduced for NCV Kalman filters and used to develop a relationship between the anticipated maximum acceleration of the target and the process noise variance that minimizes the maximum mean squared error (MaxMSE) in position. Lower bounds on the process noise variance that prevent the position MSE from exceeding the measurement noise variance were also expressed in terms of the maximum acceleration and deterministic maneuver index. In this paper, those results are summarized and codified for practical application by the target tracking community. The design methods for NCV Kalman filters with discrete white noise acceleration (DWNA) and continuous white noise acceleration (CWNA) are presented for sustained and brief maneuvers. The application of the design methods to radar tracking of maneuvering targets is also addressed. The effectiveness of the design methods is illustrated via Monte Carlo simulations.

Direct CFD simulations of standard maneuvering tests for DARPA Suboff

Maneuvering abilities of underwater vehicles are one of the primary concerns for navies and in the civil field they provide great flexibility in working in confined environments. Numerical simulations of the motions of these vessels may be conducted via system-based or direct CFD approaches. In this study, we focus on direct CFD simulations of the benchmark DARPA Suboff AFF8 Configuration. The paper starts by showing the submarine's lack of course-keeping stability using the C-index. After validation of the numerical approach by self-propulsion tests (and the determination of the propeller rotation rate to achieve the required velocity), the results of an extensive set of standard maneuvering tests are presented. Turning circle, pullout and zig-zag tests confirm that the DARPA Suboff does not have course-keeping ability. The submarine leans to the starboard side at neutral rudder angle. The maneuvering indices are investigated with respect to changing rudder angle with turning circle tests. High residual yaw rates are found in both side turnings in the pullout tests and the zig-zag tests show the submarine's inadequacy in making sharp turns. Numerical simulations reveal that the DARPA Suboff has high turning ability but no course-keeping ability.

Turning circle tests with system-based simulations in irregular waves including wave drift and propeller side forces

Controlled motion in seas require mathematical modeling of ship motions under external disturbances. Waves are one of the most influential factors that undermine ship control. In this study, we investigate the maneuvering ability of the benchmark Japan Bulk Carrier (JBC) in calm water and in waves. Turning circle tests are conducted via system-based analysis and direct CFD method in calm water condition. Comparison of system-based analysis with experiments and direct CFD method have shown to be satisfactory. After validation of the mathematical model, empirical relations are used to include the ship drift in irregular wave conditions. Two different cases are considered. The first one is with constant significant wave height and changing wave angles. The second case is with constant wave angle but different significant wave height. The ship drift was observed to be in the direction of wave propagation, growing larger with increasing wave height. The maneuvering indices with changing wave directions were graphed and it revealed the maneuvering capability of JBC under the disturbance of waves.

Potential Field Control of a Redundant Nonholonomic Mobile Manipulator with Corridor-Constrained Base Motion

This work proposes a solution for redundant nonholonomic mobile manipulator control with corridor constraints on base motion. The proposed control strategy applies an artificial potential field for base navigation to achieve joint control with desired trajectory tracking of the end effector. The overall kinematic model is created by describing the nonholonomic mobile platform and the kinematics of the manipulator. The objective function used consists of a primary control task that optimizes the joint variables to achieve the desired pose or trajectory of the end effector and a secondary control task that optimizes the joint variables for the base to support the arm and stay within the corridor. As a last priority, an additional optimization is introduced to optimize the maneuverability index. The proposed baseline navigation has global convergence without local minima and is computationally efficient. This is achieved by an optimal grid-based search on a coarse discrete grid and a bilinear interpolation to obtain a continuous potential function and its gradient. The performance of the proposed control algorithm is illustrated by several simulations of a mobile manipulator model derived for a Pal Tiago mobile base and an Emiko Franka Panda robotic manipulator.

Research on Maneuverability Prediction of Double Waterjet Propulsion High Speed Planing Craft

A mathematical model for predicting the maneuvering motion of a ship is constructed, using a planing craft with dual waterjet propulsion as the object of study. This model is based on the standard approach of the MMG (Maneuvering Modeling Group) and uses the Runge–Kutta algorithm to solve the differential equations. For the simulation of the turning and Z-shape maneuvering motion, the RANS equation is first solved using the program STAR-CCM + and then the PMM motion of the hull is simulated using the overlapping grid approach to derive the hydrodynamic derivative. The established method for predicting the ship’s maneuverability is feasible, as shown by the calculated results, which agree well with those obtained using data from the sea trials. This method was used to simulate the rudder rotation and Z-shape motion of the planing craft at medium and high speeds to predict the maneuverability index.

Research on sensitivity analysis method of ship hydrodynamic derivatives based on intelligent control

Objectives In order to obtain a simplified mathematical model of ship motion used for intelligent control, Methods This paper takes the Mariner class vessel as the research object, and proposes a sensitivity analysis method combining standard maneuverability test and PID heading control test. Compound analysis include the control index, maneuverability index, and the squared loss of typical motion state variables throughout the entire process is performed to obtain a data set containing multi-dimensional sensitivity coefficients. K-means machine learning algorithm is introduced to perform cluster analysis on the data set. The sensitivity division of hydrodynamic derivatives is completed and the model is simplified. Results The contrastive simulation tests of heading control and track control among the simplified model, the former simplified model and the complete model are carried out, the results show that the sensitivity analysis method proposed in this paper is effective and the model proposed in this paper has higher control prediction accuracy. Conclusions The research shows that the method proposed in this paper has certain significance for guiding the ship motion modeling for intelligent control.

Geometric method for researching the robot service area under the obstacles for the limitations on links movement

The work is devoted to solving one of the problems of robot motion virtual simulation using computer graphics. The paper offers a method for studying the shape and position of the work envelop of manipulator mechanisms in the presence of restricted work envelopes in the workspace. The method for determining the work envelope is based on the construction of allowed configuration of robot mechanisms. A parameter describing the structure and maneuverability index in different parts of the work envelope is proposed. The construction of cross sections of service areas for different positions of restricted work envelopes allows determining the areas where the output link centers of various mechanisms can not be located. The conducted research makes it possible to place the trajectories of the output link in solving motion problems, which reduce the probability of deadlocks in the automated motion synthesis along the velocity vector.

Theoretical background and application of MANSIM for ship maneuvering simulations

In this study, a new developed code, MANSIM (MANeuvering SIMulation) for ship maneuvering simulations and its theoretical background are introduced. To investigate the maneuverability of any low-speed ship with single-rudder/single-propeller (SPSR) or twin-rudder/twin-propeller (TPTR) configurations, a 3-DOF modular mathematical model or empirical approaches can be utilized in MANSIM. In addition to certain maneuvers of ships such as turning or zigzag, free maneuver can also be simulated. Input parameters required to solve the equations of motion can be estimated practically by several empirical formulas embedded in the software. Graphical user interface of the code has simple design to enable users to perform maneuvering calculations easily. In addition to results such as advance, transfer, tactical diameters etc. on the user interface, simulation results can also be analyzed graphically; thus it is possible to examine the variation of kinematic parameters during simulation. Using the code, maneuverabilities of a tanker ship (KVLCC2) and a surface combatant (DTMB5415) is investigated and computed results are compared with free running data for validation purpose. MANSIM can be advantageous for parametric studies and it is a valuable tool especially for sensitivity analysis on ship maneuvering. The software is available online at www.mansim.org. The effects of variation of hydrodynamic derivatives and rudder parameters on general maneuvering performance of ships are investigated by performing sensitivity analyses. It is found that linear moment derivatives and rudder parameters are highly effective in maneuvering motion. Another interesting outcome of this study is identification of the significance of third order coupled derivatives for DTMB5415 hull. Effects of linear derivatives on maneuvering indices are also investigated by MANSIM. Results show that there is not a linear relationship between hydrodynamic derivatives and maneuvering indices.

The Wheeled Vehicle Forced Additional Turn Analytical Study

The study is dedicated to increasing open pit trucks with electrical transmission maneuverability indices. The possibility of forced controllability usage of rear traction wheels of open pit truck with the electrical transmission, which enables them to carry out maneuvers with the usage of a forced additional turn is presented. For the first time, there has been worked out a mathematical model of the forced additional turn. It enables to determine a correlation of rotational speed ratio of rear traction wheels of starboard and port sides of the wheeled vehicle relative to a tire-to-surface friction coefficient. Firstly, the analytical dependences, which allow predicting the indices of open pit trucks maneuverability while using the forced additional turn are determined. The mathematical model adopted to appropriate truck's electric drive control algorithm can lead to trucks performance increasing by means of maneuvering time reducing.

Proposal of maneuverability index for remote control systems focusing on the “sense of unity” and its verification

Proposal of maneuverability index for remote control systems focusing on the “sense of unity” and its verification

Investigation of maneuverability index for remote control robots focusing on the “sense of unity”

Investigation of maneuverability index for remote control robots focusing on the “sense of unity”

Quantification of Working Volumes, Exposure, and Target-Specific Maneuverability of the Pterional Craniotomy and Its Minimally Invasive Variants

Quantitative comparison of minimally invasive and standard cranial approaches remains a methodologic challenge. The aim of this study was to apply a new digital, navigation-based method to quantify multiple parameters of the pterional, supraorbital, lateral supraorbital and mini-pterional approaches and to describe a target-specific maneuverability score. Supraorbital, lateral supraorbital, mini-pterional, and standard pterional craniotomies were performed on 8 sides in 4 cadaver heads. The limits of superficial and deep exposure and surgical target points were registered with image-guidance (Medtronic Stealth). A custom software (Guided Therapeutics Eyes II Software [GTxEyesII]) calculated superficial and deep surface areas, working volumes, and target distances. Volumes were reconstructed digitally and visualized with GTxEyesII. Finally, we defined for each approach a target-specific maneuverability score based on surface exposure, target distance, target position, and anatomical obstacles. Surface exposure and volumes were significantly smaller for keyhole approaches compared with standard pterional craniotomy (P < 0.01). Maneuverability index scores showed the greatest values for standard pterional craniotomies, but nearly equally high scores could be achieved by one or several of the less-invasive approaches for most of the targets. The combination of a navigation-based measurement method with custom software (GTxEyesII) provides a powerful tool for visualization and quantification of surgical approaches. Compared with standard pterional craniotomy, alternative keyhole craniotomies offer comparable deep exposure with smaller working volumes and relatively high maneuverability for specific targets.

Modeling of ship maneuvering motion using neural networks

In this paper, Neural Networks (NNs) are used in the modeling of ship maneuvering motion. A nonlinear response model and a linear hydrodynamic model of ship maneuvering motion are also investigated. The maneuverability indices and linear non-dimensional hydrodynamic derivatives in the models are identified by using two-layer feed forward NNs. The stability of parametric estimation is confirmed. Then, the ship maneuvering motion is predicted based on the obtained models. A comparison between the predicted results and the model test results demonstrates the validity of the proposed modeling method.

Numerical Investigation on Transverse Maneuverability of a Vectored Underwater Vehicle Without Appendage

[abstFig src='/00280003/13.jpg' width=""300"" text='Solid model of a vectored underwater vehicle' ] Vectored underwater vehicles (VUVs) are receiving increasing research attention, in part for their maneuverability. In our work, we apply a novel vectored thruster based on a spherical parallel mechanism to an underwater vehicle. We present and calculate the scaling factor based on the vectored thruster’s configuration parameters and set up a six DOF kinematic model. We construct a nonlinear dynamic model of the VUV without appendages using the Newton-Euler method. To demonstrate the VUV’s transverse maneuverability, we set up a perturbation model in a complex domain using Laplacian transformation, and propose the stability margin of vectored propulsion as a maneuverability index. Many numerical examples are provided to verify the maneuverability of the VUV.

半滑走型高速船の操縦性能

In this paper, the effects of hull attitude change, ship speed, metacentric height GM and stern appendages such as rudder, shaft bracket, bossing and propeller shaft on maneuverability of a high speed vessel are investigated. Range of Froude number of the studied ship is from 0.6 to 1.0. The hydrodynamic force characteristics are captured by a Circular Motion Test in Hiroshima University Towing Tank. Using the hydrodynamic derivatives, maneuverability indices are calculated. As a result, the following knowledge is obtained through the study: by inclusion of ship attitude change, Y'υ increases, N'r slightly decreases, Y'r -m'x and N'υ significantly increase. The effect of the attitude change is not negligible. Inclusion of the attitude change improves the course stability due to contribution of Y'r and -m'x and N'υ. When ship speed increases and GM decreases, the course stability becomes worse in general although the turning performance is improved. This tendency is the same for displacement typed ships. The bare hull ship becomes unstable for course keeping in any Froude numbers, although the ship with stern appendages is stable. Thus, the effect of stern appendages on the course stability is considerably large. This is mainly due to the increase of absolute values of Y'υ and N'r by the stern appendages.

Optimization Calculation on Maneuverability Index of Small Scale Ship Model

The small-scale self-propelled ship model plays an important role in studying the navigability of a waterway. The model is usually calibrated with Z-type tests. In order to improve traditional Z-type tests, this paper developed new methods for estimating ship model maneuverability indexes. Based on momentum theorem, all parameters such as rudder angle, drift angle, heading angle associate with turning quality index, K, and turning lag index, T, were simplified to be related to the time parameters associated with ship movement. The methods were verified with observed data based on real ships.

Stability condition and steady‐state solution of various α–β filters for linear FM pulse compression radars

AbstractPulse compression is often used in radar to increase the detection range while suppressing the peak transmission power and to prevent a drop in the range resolution. However, a drawback of this technique is the target range is observed offset by an amount proportional to the range rate of the target. On the other hand, various α–β filters have been derived based on the differences in motion models. These filters define the process noise in a discrete system in terms of the velocity, the acceleration, or the n‐th derivative of the acceleration, or discretized after defining the process noise in a continuous system in terms of the acceleration. For the process noise in a discrete system defined in terms of the acceleration, we propose an α–β filter that tracks while internally correcting the bias observation error described above. In this paper, we show a necessary and sufficient stability condition of various stable α–β filters that track while internally correcting the bias observation error. We show that the stable gain region does not depend on the Doppler shift time constant and is invariant. Then we formulate the relationship between α and β and the error covariance matrix. In addition, for α–β filters where the process noise in a discrete system is defined in terms of the velocity or the acceleration, or where the process noise in a continuous system is defined in terms of the acceleration and then discretized, we showed that, in practice, the α–β filter with the process noise defined in terms of the velocity in discrete time, has superior performance, when the performance is measured in terms of error covariance matrix given a fixed maneuver index. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(6): 13–22, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10134

Kalman filter versus IMM estimator: when do we need the latter?

In this paper, a performance comparison between a Kalman filter and the interacting multiple model (IMM) estimator is carried out for single-target tracking. In a number of target tracking problems of various sizes, ranging from single-target tracking to tracking of about a thousand aircraft for air traffic control, it has been shown that the IMM estimator performs significantly better than a Kalman filter. In spite of these studies and many others, the condition under which an IMM estimator is desirable over a single model Kalman filter versus an IMM estimator are quantified here in terms of the target maneuvering index, which is a function of target motion uncertainty, measurement uncertainty, and sensor revisit interval. Using simulation studies, it is shown that above a certain maneuvering index an IMM estimator is preferred over a Kalman filter to track the target motion. These limits should serve as a guideline in choosing the more versatile, but somewhat costlier, IMM estimator over a simpler Kalman filter.

Aerodynamic stability and maneuverability of the gliding frog Polypedates dennysi.

Gliding has evolved independently in two families of tree frog. Tree frogs glide to descend rapidly to mating sites over temporary pools on the forest floor or to escape predators. The physical mechanisms used by frogs to glide and maneuver were investigated using a combination of observations of live frogs (Polypedates dennysi) gliding in a tilted wind-tunnel and aerodynamic forces and torques measured from physical models of tree frogs in a wind-tunnel. Tree frogs maneuvered in the tilted wind-tunnel using two different turning mechanisms: a banked turn (the frog rolls into the turn) and a crabbed turn (the frog yaws into the turn). Polypedates dennysi possessed overall weak aerodynamic stability: slightly stable about the pitch and roll axis, slightly unstable about the yaw axis. The maneuverability of gliding tree frogs was quantified using a maneuverability index. The maneuverability of tree frogs was roughly equivalent for tree frogs performing a banked turn and performing a crabbed turn. The maneuverability of tree frogs was approximately one-third of the maneuverability of a falcon (Falcon jugger).