The Experts below are selected from a list of 38220 Experts worldwide ranked by ideXlab platform
Hyunggi Kim - One of the best experts on this subject based on the ideXlab platform.
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ICRA - Isotropy analysis of caster wheeled omnidirectional mobile robot
IEEE International Conference on Robotics and Automation 2004. Proceedings. ICRA '04. 2004, 2004Co-Authors: Sungbok Kim, Hyunggi KimAbstract:This paper presents a complete Isotropy analysis of an omnidirectional mobile robot with three caster wheels. All possible actuation sets with different number and combination of rotating and steering joints are considered. First, the kinematic model of a caster wheeled omnidirectional mobile robot (COMR) having n (3 /spl les/ n /spl les/ 6) actuated joints is obtained without matrix inversion. Second, with the characteristic length introduced, the Isotropy conditions of a COMR are derived, which are imposed on two Jacobian matrices. Under the Isotropy condition on one Jacobian matrix, three caster wheels should be identical with the length of the steering link equal to the radius of the wheel. Third, depending on the selection of actuated joints, the Isotropy conditions on the other Jacobian matrix are examined. The isotropic configurations of a COMR are identified, along with the Isotropy loci in the configuration space.
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ICRA - Local and Global Isotropy of Caster Wheeled Omnidirectional Mobile Robot
Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 1Co-Authors: Sungbok Kim, Hyunggi Kim, Byoungkwon MoonAbstract:The omnidirectional mobility of a mobile robot loses significance in motion control, unless the Isotropy characteristics of the mechanism is maintained well. This paper investigates the local and global Isotropy of an omnidirectional mobile robot with three caster wheels. All possible actuations with different number and combination of rotating and steering joints are considered. First, the kinematic model based on velocity decomposition and the algebraic conditions for the local Isotropy are obtained. Second, the geometric conditions for the local Isotropy are derived and all isotropic configurations are fully identified. Third, the global Isotropy index is examined to determine the optimal parameters in terms of actuation set, characteristic length, and steering link length.
Sungbok Kim - One of the best experts on this subject based on the ideXlab platform.
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ICRA - Isotropy analysis of caster wheeled omnidirectional mobile robot
IEEE International Conference on Robotics and Automation 2004. Proceedings. ICRA '04. 2004, 2004Co-Authors: Sungbok Kim, Hyunggi KimAbstract:This paper presents a complete Isotropy analysis of an omnidirectional mobile robot with three caster wheels. All possible actuation sets with different number and combination of rotating and steering joints are considered. First, the kinematic model of a caster wheeled omnidirectional mobile robot (COMR) having n (3 /spl les/ n /spl les/ 6) actuated joints is obtained without matrix inversion. Second, with the characteristic length introduced, the Isotropy conditions of a COMR are derived, which are imposed on two Jacobian matrices. Under the Isotropy condition on one Jacobian matrix, three caster wheels should be identical with the length of the steering link equal to the radius of the wheel. Third, depending on the selection of actuated joints, the Isotropy conditions on the other Jacobian matrix are examined. The isotropic configurations of a COMR are identified, along with the Isotropy loci in the configuration space.
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ICRA - Local and Global Isotropy of Caster Wheeled Omnidirectional Mobile Robot
Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 1Co-Authors: Sungbok Kim, Hyunggi Kim, Byoungkwon MoonAbstract:The omnidirectional mobility of a mobile robot loses significance in motion control, unless the Isotropy characteristics of the mechanism is maintained well. This paper investigates the local and global Isotropy of an omnidirectional mobile robot with three caster wheels. All possible actuations with different number and combination of rotating and steering joints are considered. First, the kinematic model based on velocity decomposition and the algebraic conditions for the local Isotropy are obtained. Second, the geometric conditions for the local Isotropy are derived and all isotropic configurations are fully identified. Third, the global Isotropy index is examined to determine the optimal parameters in terms of actuation set, characteristic length, and steering link length.
Byoungkwon Moon - One of the best experts on this subject based on the ideXlab platform.
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ICRA - Local and Global Isotropy of Caster Wheeled Omnidirectional Mobile Robot
Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 1Co-Authors: Sungbok Kim, Hyunggi Kim, Byoungkwon MoonAbstract:The omnidirectional mobility of a mobile robot loses significance in motion control, unless the Isotropy characteristics of the mechanism is maintained well. This paper investigates the local and global Isotropy of an omnidirectional mobile robot with three caster wheels. All possible actuations with different number and combination of rotating and steering joints are considered. First, the kinematic model based on velocity decomposition and the algebraic conditions for the local Isotropy are obtained. Second, the geometric conditions for the local Isotropy are derived and all isotropic configurations are fully identified. Third, the global Isotropy index is examined to determine the optimal parameters in terms of actuation set, characteristic length, and steering link length.
R. A. Antonia - One of the best experts on this subject based on the ideXlab platform.
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Approach to Isotropy in a smooth wall turbulent boundary layer
Fluid Dynamics Research, 2000Co-Authors: Sundara Rajagopalan, R. A. AntoniaAbstract:The approach to local Isotropy in a smooth wall turbulent boundary layer is examined using measurements of velocity spectra and moments, up to order 4, of velocity increments. The ratio of the measured spectrum of the wall normal velocity fluctuation v to that calculated using Isotropy from the measured spectrum of the longitudinal velocity fluctuation u, depends mainly on the Kolmogorov-normalized local mean strain rate and the Taylor microscale Reynolds number. These parameters also affect in a systematic way the departure from Isotropy of the u−v spectral correlation coefficient and of the v increment moments.
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Isotropy of the small scales of turbulence at low Reynolds number
Journal of Fluid Mechanics, 1993Co-Authors: John Kim, R. A. AntoniaAbstract:Spectral local Isotropy tests are applied to direct numerical simulation data, mainly at the centreline of a fully developed turbulent channel flow. Despite the small Reynolds number of the simulation, the high-wavenumber behaviour of velocity and vorticity spectra is consistent with local Isotropy. This consistency is verified by the relationship between streamwise wavenumber spectra and spanwise wavenumber spectra. The high-wavenumber behaviour of the pressure spectrum is also consistent with local Isotropy and compares favourably with the calculation of Batchelor (1951), which assumes Isotropy and joint normality of the velocity field at two points in space. The latter assumption is validated by the shape but not the magnitude of the quadruple correlation of the streamwise velocity fluctuation at small separations. There is only partial support for local spectral Isotropy away from the centreline as the magnitude of the mean strain rate increases.
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Isotropy of small scale turbulence
1992Co-Authors: R. A. Antonia, John KimAbstract:The degree to which local Isotropy is satisfied has been examined using direct numerical simulations for a fully developed channel flow. Attention is mainly given to the high wavenumber part of vorticity and temperature derivative spectra. The ratio of these spectra and their isotropic values depends on the particular quantity considered, the departure from Isotropy being more pronounced for the temperature derivative than for the vorticity. When the Kolmogorov-normalized wavenumber is sufficiently large, Isotropy is satisfied provided the (Kolmogorov-normalized) mean strain rate is sufficiently small. This result appears to be independent of the quantity considered and of the Reynolds number.
Somajit Dey - One of the best experts on this subject based on the ideXlab platform.
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Time Isotropy, Lorentz transformation and inertial frames
Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics, 2018Co-Authors: Somajit DeyAbstract:Abstract Homogeneity of Euclidean space and time, spatial Isotropy, principle of relativity and the existence of a finite speed limit (or its variants) are commonly believed to be the only axioms required for developing the special theory of relativity (Lorentz transformations). In this paper, however, it is pointed out that the Lorentz transformation for a boost cannot actually be derived without the explicit assumption of time Isotropy (viz. time-reversal symmetry) which is logically independent of the other postulates of relativity. Postulating time Isotropy also restores the symmetry between space and time in the postulates of relativity (i.e. time and space share the same symmetries then). Time Isotropy also helps explain naturally one key general feature of the fundamental physical laws, viz. their time-reversal symmetry. But inertial frames are defined in influential texts as frames having space-time homogeneity and spatial Isotropy only. Inclusion of time Isotropy in that definition is thus suggested.
