scholarly journals Clustering Point Trajectories with Various Life-Spans

Author(s):  
Matthieu Fradet ◽  
Philippe Robert ◽  
Patrick Pérez
Keyword(s):  
Author(s):  
Damien Chablat ◽  
Philippe Wenger

Abstract The goal of this paper is to define the n-connected regions in the Cartesian workspace of fully-parallel manipulators, i.e. the maximal regions where it is possible to execute point-to-point motions. The manipulators considered in this study may have multiple direct and inverse kinematic solutions. The N-connected regions are characterized by projection, onto the Cartesian workspace, of the connected components of the reachable configuration space defined in the Cartesian product of the Cartesian space by the joint space. Generalized octree models are used for the construction of all spaces. This study is illustrated with a simple planar fully-parallel manipulator.


1985 ◽  
Vol 152 ◽  
pp. 49-66 ◽  
Author(s):  
J. M. Dewey ◽  
D. J. McMillin

Shock fronts and fluid-particle trajectories throughout a two-dimensional shock wave flow have been measured by multiple schlieren photography in a detailed study of the Mach reflection from a 10° wedge of plane uniform shocks with Mach numbers of 1.105, 1.240 and 1.415. Correction of optical distortions throughout the field of view permitted the positions and shapes of the shock fronts and the magnitudes and directions of the particle velocities to be measured with a high degree of accuracy. No departure from self-similarity of the flow fields could be detected. The cross-sections of the reflected shocks were found to be circular and centred on a point which moved with the velocity of the flow behind the incident shock. The triple-point trajectories were linear. The velocity of the curved Mach stem shock was found to be constant at any one height above the wedge surface and to decrease monotonically with height. A deviation from perpendicularity was noticed where the Mach stems met the surface of the wedge, the shocks having a slight forward inclination of as much as 1°. The experimental results cannot be completely explained using the classical three-shock theory and an alternative model for weak Mach reflection is developed in Part 2 of this paper.


1974 ◽  
Vol 18 (5) ◽  
pp. 506-509 ◽  
Author(s):  
J. S. Albus ◽  
J. M. Evans ◽  
E. G. Johnsen

The problem of man controlling or programming a machine may be considered as a hierarchy of control functions, with each level of control calling up ordered sequences of operations at the next lower level, using appropriate sensory feedback for each level. Man may enter the control hierarchy at any level for direct control or for programming an automatic system for later playback. The computer carries out lower level control functions, thereby augmenting man's control capabilities. The Cerebellar Model Articulation Controller (CMAC) is a computer based control system in which high–level task–oriented commands can be broken down into a series of elemental motor actuator signals. CMAC is a general purpose adaptive control concept which can be arranged in a hierarchical structure, such as that described above, so as to facilitate the man–machine communication problem. For example, CMAC can solve the coordinate transformation problem so that commands can be given in terms of desired end point trajectories. Furthermore, CMAC can handle many feedback variables such as measurements of misalignment of parts, variable mass loading, irregularities in materials, and constraints imposed by an external environment. Concepts of man–machine communication under consideration by the NBS Automation Technology Porgram are presented with particular emphasis on the CMAC control concept.


2007 ◽  
Vol 177 (1-2) ◽  
pp. 124 ◽  
Author(s):  
H. Abbasi ◽  
M. Ghadimi ◽  
M. Jenab ◽  
N. Javaheri

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