The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Jian Min Duan - One of the best experts on this subject based on the ideXlab platform.

  • A Strong Tracking Square Root Central Difference FastSLAM for Unmanned Intelligent Vehicle With Adaptive Partial Systematic Resampling
    IEEE Transactions on Intelligent Transportation Systems, 2016
    Co-Authors: Jian Min Duan
    Abstract:

    An improved fast simultaneous localization and mapping (FastSLAM) algorithm based on the strong tracking square root Central Difference Kalman filter (STSRCDKF) with adaptive partial systematic resampling is proposed in this paper to solve the large-scale simultaneous localization and mapping (SLAM) problem for unmanned intelligent vehicle. In the proposed algorithm, STSRCDKF is composed of a strong tracking filter and a square root Central Difference Kalman filter. STSRCDKF is used to design an adaptive adjusting proposal distribution of the particle filter and to estimate the Gaussian densities of the landmarks. Moreover, an adaptive partial systematic resampling operation is carried out to reduce the degree of particle degeneracy and maintain the diversity of particles. The performance of the proposed algorithm is compared with that of Central Difference FastSLAM and FastSLAM2.0; the simulation results based on the simulator and two benchmark data sets verify that the proposed algorithm has better adaptability and robustness to respond with time-varying measurement noise. In addition, it reduces computational cost and improves state estimation accuracy and consistency. Furthermore, the validity of the proposed algorithm is verified by the experimental result in campus test site of Beijing University of Technology.

  • An Improved FastSLAM Algorithm for Autonomous Vehicle Based on the Strong Tracking Square Root Central Difference Kalman Filter
    IEEE Conference on Intelligent Transportation Systems Proceedings ITSC, 2015
    Co-Authors: Jian Min Duan, Hong Xiao Yu, Dan Liu, Hui Shi
    Abstract:

    Fast simultaneous localization and mapping (FastSLAM), a popular algorithm based on the Rao-Blackwellized Particle Filter, has been used to solve the large-scale simultaneous localization and mapping (SLAM) problem for autonomous vehicle, but it suffers from two serious shortcomings: one is the calculation of Jacobian matrices and the linear approximations of the nonlinear vehicle kinematics model and the nonlinear environment measurement model, the other is particle set degeneracy due to inaccurate proposal distribution of particle filter. Hence an improved FastSLAM algorithm based on the strong tracking square root Central Difference Kalman filter (STSRCDKF) is proposed in this paper to overcome these problems. In the proposed algorithm, STSRCDKF is based on the combination of a strong tracking filter (STF) and a square root Central Difference Kalman filter (SRCDKF), STSRCDKF is used to design an adaptive adjustment proposal distribution of the particle filter and to estimate the Gaussian densities of the feature landmarks. The performance of the proposed algorithm is compared with that of UFastSLAM and FastSLAM2.0 in simulations and experimental tests, the results verify that the proposed algorithm has better adaptability and robustness. Furthermore, it reduces computational cost and improves state estimation accuracy and consistency.

B. Wu - One of the best experts on this subject based on the ideXlab platform.

  • Analysis and Preliminary Experimental Study on Central Difference Method for Real-time Substructure Testing
    2020
    Co-Authors: B. Wu, Q. Wang
    Abstract:

    Central Difference method (CDM) that is explicit for pseudo dynamic testing is also supposed to be explicit for real-time substructure testing (RST). However, to obtain correct velocity dependent restoring force of the physical substructure being tested, the target velocity is required to be calculated as well as displacement. The standard CDM provides only explicit target displacement but not explicit target velocity. This paper investigates the necessary modification of standard Central Difference method when applied to RST and analyzes the stability of the modified CDM for RST (CDM-RST). The analysis shows that the stability of the CDM-RST decreases with increasing damping ratio of the physical substructure. Then a preliminary experimental research is described. The test shows that the calculated result agrees well with the tested one when the damping ratio of the specimen (i.e., damper) is relatively low, but the discrepancy between the tested and calculated responses increases with the increasing damping ratio of the specimen.

  • stability of Central Difference method for dynamic real time substructure testing
    Earthquake Engineering & Structural Dynamics, 2009
    Co-Authors: B. Wu, L. Deng, X. Yang
    Abstract:

    This paper studies the stability of the Central Difference method (CDM) for real-time substructure test considering specimen mass. Because the standard CDM is implicit in terms of acceleration, to avoid iteration, an explicit acceleration formulation is assumed for its implementation in real-time dynamic substructure testing. The analytical work shows that the stability of the algorithm decreases with increasing specimen mass if the experimental substructure is a pure inertia specimen. The algorithm becomes unstable however small the time integration interval is, when the mass of specimen equal or greater than that of its numerical counterpart. For the case of dynamic specimen, the algorithm is unstable when there is no damping in the whole test structure; a damping will make the algorithm stable conditionally. Part of the analytical results is validated through an actual test. Copyright © 2009 John Wiley & Sons, Ltd.

  • Stability analysis of Central Difference method for dynamic real-time substructure testing
    2009 American Control Conference, 2009
    Co-Authors: B. Wu, L. Deng, Z. Wang, X. Yang
    Abstract:

    This paper studies the stability of the Central Difference method (CDM) for real-time substructure test considering the mass of specimen (i.e., experimental substructure). To obtain correct reaction inertia force, an explicit acceleration formulation is assumed for the CDM. The analytical work shows that the stability of the algorithm decreases with increasing specimen mass if the experimental substructure is a pure inertia specimen. The algorithm becomes unstable whatever the time integration interval, i.e., unconditionally unstable, when the mass of specimen equal or greater than that of its numerical counterpart. For the case of dynamic specimen, the algorithm is unconditionally unstable when there is no damping in the whole test structure; a damping will make the algorithm stable conditionally. The behavior of the CDM for vanishing time integration interval is verified with the zero-stability analysis method for coupled integration. Part of the analytical results is validated by an actual test.

  • ACC - Stability analysis of Central Difference method for dynamic real-time substructure testing
    2009 American Control Conference, 2009
    Co-Authors: B. Wu, L. Deng, Zhen-bo Wang, X. Yang
    Abstract:

    This paper studies the stability of the Central Difference method (CDM) for real-time substructure test considering the mass of specimen (i.e., experimental substructure). To obtain correct reaction inertia force, an explicit acceleration formulation is assumed for the CDM. The analytical work shows that the stability of the algorithm decreases with increasing specimen mass if the experimental substructure is a pure inertia specimen. The algorithm becomes unstable whatever the time integration interval, i.e., unconditionally unstable, when the mass of specimen equal or greater than that of its numerical counterpart. For the case of dynamic specimen, the algorithm is unconditionally unstable when there is no damping in the whole test structure; a damping will make the algorithm stable conditionally. The behavior of the CDM for vanishing time integration interval is verified with the zero-stability analysis method for coupled integration. Part of the analytical results is validated by an actual test.

  • stability and accuracy analysis of the Central Difference method for real time substructure testing
    Earthquake Engineering & Structural Dynamics, 2005
    Co-Authors: B. Wu, Jinping Ou, S Tian
    Abstract:

    The Central Difference method (CDM) that is explicit for pseudo-dynamic testing is also believed to be explicit for real-time substructure testing (RST). However, to obtain the correct velocity dependent restoring force of the physical substructure being tested, the target velocity is required to be calculated as well as the displacement. The standard CDM provides only explicit target displacement but not explicit target velocity. This paper investigates the required modification of the standard Central Difference method when applied to RST and analyzes the stability and accuracy of the modified CDM for RST. Copyright © 2005 John Wiley & Sons, Ltd.

X. Yang - One of the best experts on this subject based on the ideXlab platform.

  • stability of Central Difference method for dynamic real time substructure testing
    Earthquake Engineering & Structural Dynamics, 2009
    Co-Authors: B. Wu, L. Deng, X. Yang
    Abstract:

    This paper studies the stability of the Central Difference method (CDM) for real-time substructure test considering specimen mass. Because the standard CDM is implicit in terms of acceleration, to avoid iteration, an explicit acceleration formulation is assumed for its implementation in real-time dynamic substructure testing. The analytical work shows that the stability of the algorithm decreases with increasing specimen mass if the experimental substructure is a pure inertia specimen. The algorithm becomes unstable however small the time integration interval is, when the mass of specimen equal or greater than that of its numerical counterpart. For the case of dynamic specimen, the algorithm is unstable when there is no damping in the whole test structure; a damping will make the algorithm stable conditionally. Part of the analytical results is validated through an actual test. Copyright © 2009 John Wiley & Sons, Ltd.

  • Stability analysis of Central Difference method for dynamic real-time substructure testing
    2009 American Control Conference, 2009
    Co-Authors: B. Wu, L. Deng, Z. Wang, X. Yang
    Abstract:

    This paper studies the stability of the Central Difference method (CDM) for real-time substructure test considering the mass of specimen (i.e., experimental substructure). To obtain correct reaction inertia force, an explicit acceleration formulation is assumed for the CDM. The analytical work shows that the stability of the algorithm decreases with increasing specimen mass if the experimental substructure is a pure inertia specimen. The algorithm becomes unstable whatever the time integration interval, i.e., unconditionally unstable, when the mass of specimen equal or greater than that of its numerical counterpart. For the case of dynamic specimen, the algorithm is unconditionally unstable when there is no damping in the whole test structure; a damping will make the algorithm stable conditionally. The behavior of the CDM for vanishing time integration interval is verified with the zero-stability analysis method for coupled integration. Part of the analytical results is validated by an actual test.

  • ACC - Stability analysis of Central Difference method for dynamic real-time substructure testing
    2009 American Control Conference, 2009
    Co-Authors: B. Wu, L. Deng, Zhen-bo Wang, X. Yang
    Abstract:

    This paper studies the stability of the Central Difference method (CDM) for real-time substructure test considering the mass of specimen (i.e., experimental substructure). To obtain correct reaction inertia force, an explicit acceleration formulation is assumed for the CDM. The analytical work shows that the stability of the algorithm decreases with increasing specimen mass if the experimental substructure is a pure inertia specimen. The algorithm becomes unstable whatever the time integration interval, i.e., unconditionally unstable, when the mass of specimen equal or greater than that of its numerical counterpart. For the case of dynamic specimen, the algorithm is unconditionally unstable when there is no damping in the whole test structure; a damping will make the algorithm stable conditionally. The behavior of the CDM for vanishing time integration interval is verified with the zero-stability analysis method for coupled integration. Part of the analytical results is validated by an actual test.

Eli Turkel - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Several Dissipation Algorithms for Central Difference Schemes
    13th Computational Fluid Dynamics Conference, 1997
    Co-Authors: R C Swanson, Rolf Radespiel, Eli Turkel
    Abstract:

    Several algorithms for introducing artificial dissipation into a Central Difference approximation to the Euler and Navier Stokes equations are considered. The focus of the paper is on the convective upwind and split pressure (CUSP) scheme, which is designed to support single interior point discrete shock waves. This scheme is analyzed and compared in detail with scalar and matrix dissipation (MATD) schemes. Resolution capability is determined by solving subsonic, transonic, and hypersonic flow problems. A finite-volume discretization and a multistage time-stepping scheme with multigrid are used to compute solutions to the flow equations. Numerical results are also compared with either theoretical solutions or experimental data. For transonic airfoil flows the best accuracy on coarse meshes for aerodynamic coefficients is obtained with a simple MATD scheme.

  • Central Difference tvd schemes for time dependent and steady state problems
    Journal of Computational Physics, 1993
    Co-Authors: P Jorgenson, Eli Turkel
    Abstract:

    We use Central Differences to solve the time dependent Euler equations. The schemes are all advanced using a Runge-Kutta formula in time. Near shocks, a second Difference is added as an artificial viscosity. This reduces the scheme to a first order upwind scheme at shocks. The switch that is used guarantees that the scheme is locally total variation diminishing (TVD). For steady state problems it is usually advantageous to relax this condition. Then small oscillations do not activate the switches and the convergence to a steady state is improved. To sharpen the shocks, different coefficients are needed for different equations and so a matrix valued dissipation is introduced and compared with the scalar viscosity. The connection between this artificial viscosity and flux limiters is shown. Any flux limiter can be used as the basis of a shock detector for an artificial viscosity. We compare the use of the van Leer, van Albada, mimmod, superbee, and the 'average' flux limiters for this Central Difference scheme. For time dependent problems, we need to use a small enough time step so that the CFL was less than one even though the scheme was linearly stable for larger time steps. Using a total variation bounded (TVB) Runge-Kutta scheme yields minor improvements in the accuracy.

  • on Central Difference and upwind schemes
    Journal of Computational Physics, 1992
    Co-Authors: R C Swanson, Eli Turkel
    Abstract:

    A class of numerical dissipation models for Central-Difference schemes constructed with second- and fourth-Difference terms is considered. The notion of matrix dissipation associated with upwind schemes is used to establish improved shock capturing capability for these models. In addition, conditions are given that guarantee that such dissipation models produce a TVD scheme. Appropriate switches for this type of model to ensure satisfaction of the TVD property are presented. Significant improvements in the accuracy of a Central-Difference scheme are demonstrated by computing both in viscid and viscous transonic airfoil flows.

Jan Nordstrom - One of the best experts on this subject based on the ideXlab platform.

  • Uniformly Best Wavenumber Approximations by Spatial Central Difference Operators: An Initial Investigation
    Lecture Notes in Computational Science and Engineering, 2020
    Co-Authors: Viktor Linders, Jan Nordstrom
    Abstract:

    A characterisation theorem for best uniform wavenumber approximations by Central Difference schemes is presented. A Central Difference stencil is derived based on the theorem and is compared with dispersion relation preserving schemes and with classical Central Differences for a relevant test problem.

  • uniformly best wavenumber approximations by spatial Central Difference operators
    Journal of Computational Physics, 2015
    Co-Authors: Viktor Linders, Jan Nordstrom
    Abstract:

    We construct accurate Central Difference stencils for problems involving high frequency waves or multi-frequency solutions over long time intervals with a relatively coarse spatial mesh, and with an easily obtained bound on the dispersion error. This is done by demonstrating that the problem of constructing Central Difference stencils that have minimal dispersion error in the infinity norm can be recast into a problem of approximating a continuous function from a finite dimensional subspace with a basis forming a Chebyshev set. In this new formulation, characterising and numerically obtaining optimised schemes can be done using established theory.