The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform

Asit Saha - One of the best experts on this subject based on the ideXlab platform.

  • bifurcation periodic and chaotic motions of the modified equal width burgers mew burgers equation with external periodic perturbation
    Nonlinear Dynamics, 2017
    Co-Authors: Asit Saha
    Abstract:

    The modified equal width-Burgers (MEW-Burgers) equation is introduced for the first time. The bifurcation behavior of the MEW-Burgers equation is studied. Considering an external periodic perturbation, the periodic and chaotic motions of the perturbed MEW-Burgers equation are investigated by using phase projection analysis, time series analysis, Poincare Section and bifurcation diagram. The strength (\(f_0\)) of the external periodic perturbation plays a crucial role in the periodic and chaotic motions of the perturbed MEW-Burgers equation.

  • dynamics of the positron acoustic waves in electron positron ion magnetoplasmas
    Indian Journal of Physics, 2017
    Co-Authors: Asit Saha, Prasanta Chatterjee
    Abstract:

    Dynamics of the positron acoustic waves in electron–positron–ion (e–p–i) magnetoplasmas with \(\kappa \)-distributed hot electrons and positrons is investigated in the frameworks of the Kadomtsev–Petviashili (KP) and modified Kadomtsev–Petviashili (mKP) equations. Employing the reductive perturbation technique, the KP and mKP equations are derived. Using the bifurcation theory of planar dynamical systems, the positron acoustic solitary wave solutions, the kink and anti-kink wave solutions are obtained. Considering an external periodic perturbation in the electron–positron–ion magnetoplasmas, the perturbed KP and mKP equations are studied via some qualitative and quantitative approaches. To corroborate in the fact that the perturbed KP and mKP equations can indeed give rise to the quasiperiodic and chaotic motions, the phase plane plots, time series plots, and the Poincare Section are used. The quasiperiodic and developed chaos can be observed for the perturbed positron acoustic waves. The frequency (\(\omega \)) of the external periodic perturbation plays the role of the switching parameter in chaotic motions of the perturbed positron acoustic waves through quasiperiodic route to chaos. This work can be useful to understand the dynamics of nonlinear electromagnetic perturbations in space and laboratory plasmas consisting of \(\kappa \)-distributed hot electrons and positrons.

Qing Wang - One of the best experts on this subject based on the ideXlab platform.

  • Chaotic characteristic analysis of spatial parallel mechanism with clearance in spherical joint
    Nonlinear Dynamics, 2018
    Co-Authors: Wenhua Gao, Qing Wang
    Abstract:

    The spherical joint is one of the main motion pairs in spatial parallel mechanism, and the spherical clearance has a great effect on the nonlinear dynamic performance of parallel mechanism. Most previous studies mainly focused on planar mechanism with revolute joint, spatial parallel mechanism with spherical clearance researched rarely. In this paper, the chaotic characteristic analysis of spatial 4-UPS (universal joint-prismatic pair-spherical joint)-RPU (revolute joint-prismatic pair-universal joint) parallel mechanism with spherical clearance is investigated. The models of spherical joint with clearance are established, and then the nonlinear dynamics equation of the parallel mechanism with spherical clearance is derived by Lagrange method. The influence of clearance on displacement, velocity and acceleration of moving platform is both analyzed. And the influence of different clearance sizes on contact force and center trajectory of the spherical clearance is analyzed, and the chaotic characteristics of spherical joint and the mechanism are all studied by phase diagram, Poincare Section mapping method and Lyapunov exponent. The results show that spherical clearance has great influence on the nonlinear dynamic performance of 4-UPS-RPU parallel mechanism, and chaos exists in the dynamic response of spherical clearance and the mechanism. As the clearance value increases, the stability of the mechanism is weakened. When the clearance value increases to 2.1 mm, chaotic motion appeared on the moving platform of the mechanism. This research is a useful attempt to study the nonlinear dynamics characteristic of parallel mechanisms with spherical clearance, which has guiding significance and practical value for further research on the design and chaotic control of parallel mechanism.

Jinjun Shan - One of the best experts on this subject based on the ideXlab platform.

  • the bifurcation of periodic orbits and equilibrium points in the linked restricted three body problem with parameter ω
    Chaos, 2019
    Co-Authors: Yuying Liang, Jinjun Shan, Mingpei Lin
    Abstract:

    This paper is devoted to the bifurcation of periodic orbits and libration points in the linked restricted three-body problem (LR3BP). Inherited from the classic circular restricted three-body problem (CR3BP), it retains most of the dynamical structure of CR3BP, while its dynamical flow is dominated by angular velocity ω and Jacobi energy C. Thus, for the first time, the influence of the angular velocity in the three-body problem is discussed in this paper based on ω-motivated and C-motivated bifurcation. The existence and collision of equilibrium points in the LR3BP are investigated analytically. The dynamic bifurcation of the LR3BP under angular velocity variation is obtained based on three typical kinds of periodic orbits, i.e., planar and vertical Lyapunov orbits and Halo orbits. More bifurcation points are supplemented to Doedel's results in the CR3BP for a global sketch of bifurcation families. For the first time, a new bifurcation phenomenon is discovered that as ω approaches to 1.4, two period-doubling bifurcation points along the Halo family merge together. It suggests that the number and the topological type of bifurcation points themselves can be altered when the system parameter varies in LR3BP. Thus, it is named as “bifurcation of bifurcation” or “secondary bifurcation” in this paper. At selected values of ω, the phase space structures of equilibrium points L2 and L3 are revealed by Lie series method numerically, presenting the center manifolds on the Poincare Section and detecting three patterns of evolution for center manifolds in LR3BP.This paper is devoted to the bifurcation of periodic orbits and libration points in the linked restricted three-body problem (LR3BP). Inherited from the classic circular restricted three-body problem (CR3BP), it retains most of the dynamical structure of CR3BP, while its dynamical flow is dominated by angular velocity ω and Jacobi energy C. Thus, for the first time, the influence of the angular velocity in the three-body problem is discussed in this paper based on ω-motivated and C-motivated bifurcation. The existence and collision of equilibrium points in the LR3BP are investigated analytically. The dynamic bifurcation of the LR3BP under angular velocity variation is obtained based on three typical kinds of periodic orbits, i.e., planar and vertical Lyapunov orbits and Halo orbits. More bifurcation points are supplemented to Doedel's results in the CR3BP for a global sketch of bifurcation families. For the first time, a new bifurcation phenomenon is discovered that as ω approaches to 1.4, two period-doub...

  • Low-energy lunar transfers using spatial transit orbits
    Communications in Nonlinear Science and Numerical Simulation, 2014
    Co-Authors: Jinjun Shan
    Abstract:

    Abstract This paper is concerned with natural and artificial low-energy lunar transfers in three-dimensional space. The main contribution of this paper is that the limitations of the planar manifold assumption, which is adopted in previous low-energy orbit design methods, are avoided by describing the transfer orbits with more realistic spatial transit and non-transit orbits. To start, the limitations of the previous design methods for the low-energy trajectories are highlighted, and the boundaries of the spatial transit orbits, which can enter into or escape from the potential well near the Moon through the L 1 or L 2 bottleneck regions of the zero velocity surface, are defined on a Poincare Section by using the necessary and sufficient condition of transition. Next, by considering the dominant gravity bodies in different orbit segments the motion near the Moon is analyzed in the Earth–Moon circular restricted three-body problem (CR3BP). For natural celestial bodies, the statistical characteristics of the lunar collision trajectories are studied. For the artificial celestial bodies, the investigation is focused on the achievable range of inclination and height of the low lunar orbit (LLO). Then, the motion between the Earth and the Moon is studied in the Earth–Moon based Sun-perturbed bicircular four-body problem (B4BP). For natural and artificial celestial bodies, the Earth-origin trajectories and the trajectories from the low Earth orbits are analyzed. Compared to the current planar manifold based design methods, the technique introduced in this paper can evaluate the lunar transfer orbits more accurately. Also, some lunar transfer trajectories which do not exist in the manifold based models can be found, and the heights and inclinations of the parking orbits around the Earth and the Moon can also be analyzed.

Nasser Mozayani - One of the best experts on this subject based on the ideXlab platform.

  • a new criterion to distinguish stochastic and deterministic time series with the Poincare Section and fractal dimension
    Chaos, 2009
    Co-Authors: Abbas Golestani, M Jahed R Motlagh, Kushan Ahmadian, Amir Omidvarnia, Nasser Mozayani
    Abstract:

    In this paper, we propose a new method for detecting regular behavior of time series: this method is based on the Poincare Section and the Higuchi fractal dimension. The new method aims to distinguish random signals from deterministic signals. In fact, our method provides a pattern for decision making about whether a signal is random or deterministic. We apply this method to different time series, such as chaotic signals, random signals, and periodic signals. We apply this method to examples from all types of route to chaotic signals. This method has also been applied to data about iris tissues. The results show that the new method can distinguish different types of signals.

Wenhua Gao - One of the best experts on this subject based on the ideXlab platform.

  • Chaotic characteristic analysis of spatial parallel mechanism with clearance in spherical joint
    Nonlinear Dynamics, 2018
    Co-Authors: Wenhua Gao, Qing Wang
    Abstract:

    The spherical joint is one of the main motion pairs in spatial parallel mechanism, and the spherical clearance has a great effect on the nonlinear dynamic performance of parallel mechanism. Most previous studies mainly focused on planar mechanism with revolute joint, spatial parallel mechanism with spherical clearance researched rarely. In this paper, the chaotic characteristic analysis of spatial 4-UPS (universal joint-prismatic pair-spherical joint)-RPU (revolute joint-prismatic pair-universal joint) parallel mechanism with spherical clearance is investigated. The models of spherical joint with clearance are established, and then the nonlinear dynamics equation of the parallel mechanism with spherical clearance is derived by Lagrange method. The influence of clearance on displacement, velocity and acceleration of moving platform is both analyzed. And the influence of different clearance sizes on contact force and center trajectory of the spherical clearance is analyzed, and the chaotic characteristics of spherical joint and the mechanism are all studied by phase diagram, Poincare Section mapping method and Lyapunov exponent. The results show that spherical clearance has great influence on the nonlinear dynamic performance of 4-UPS-RPU parallel mechanism, and chaos exists in the dynamic response of spherical clearance and the mechanism. As the clearance value increases, the stability of the mechanism is weakened. When the clearance value increases to 2.1 mm, chaotic motion appeared on the moving platform of the mechanism. This research is a useful attempt to study the nonlinear dynamics characteristic of parallel mechanisms with spherical clearance, which has guiding significance and practical value for further research on the design and chaotic control of parallel mechanism.