On some aspects of kinematic properties of parallel manipulators destined for some new applications

Abstract This paper presents a study of the workspace and kinematic properties of four different architectures of six-degree-of-freedom parallel mechanisms. For each architecture, the volume of the Cartesian workspace is computed at different orientations of the moving platform. The distribution of the workspace is also found by computing the 2D sections of the 3D workspace. The rotational workspace is then determined at the reference position of the platform. Finally, the stiffness properties of the architectures are obtained. Normalization factors are then defined to account for the structural differences between the architectures of mechanisms. The comparison of the different architectures of parallel mechanisms has been performed using SIMPA, a specialized CAD tool developed for the kinematic analysis and optimization of parallel manipulators. The results thus obtained illustrate the range of performance which can be expected from different parallel architectures. Although none of the architectures proves to be better than all the others in all respects, particular architectures do excel in particular performance measures. The approach proposed would therefore be useful in further studies relating to the design and optimization of parallel manipulators and mechanisms.

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Experimental Results of a 3-DOF Parallel Manipulator as an Earthquake Motion Simulator

Volume 2: 28th Biennial Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2004-57075 ◽

2004 ◽

Cited By ~ 11

Author(s):

Erika Ottaviano ◽

Marco Ceccarelli ◽

Gianni Castelli

Keyword(s):

Parallel Manipulator ◽

Linear Acceleration ◽

Parallel Manipulators ◽

Experimental Results ◽

Civil Structures ◽

Serial Manipulators ◽

Earthquake Motion ◽

Motion Simulator ◽

Earthquake Effects ◽

New Applications

Parallel manipulators are increasingly used in new applications by exploiting their better characteristics with respect to those of serial manipulators, such as higher stiffness, velocity and acceleration, payload. In this paper, experimental results are presented of a novel application of a 3-DOF CaPaMan (Cassino Parallel Manipulator) prototype to simulate point seismograms and 3D earthquake motion. The rigid body acceleration (linear acceleration, angular velocity and acceleration) has been experimentally analyzed to simulate real 3D earthquakes by using the parallel manipulator. Furthermore, first experimental results are reported to analyze earthquake effects on scaled civil structures.

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The Design Considerations of Manipulators

Volume 7A: 26th Biennial Mechanisms and Robotics Conference ◽

10.1115/detc2000/mech-14089 ◽

2000 ◽

Author(s):

K. Y. Tsai ◽

K. D. Huang

Keyword(s):

Optimum Design ◽

Parallel Manipulators ◽

Modular Approach ◽

Design Considerations ◽

Serial Chains ◽

Kinematic Properties

Abstract This paper presents algorithms to evaluate various kinematic properties of manipulators and then studies how to utilize the obtained result in the design of manipulators. The manipulability, workspace volume, and force transmissivity of various serial chains are first evaluated. The obtained data are compared and listed on tables that can be used for designing serial and in-parallel manipulators. A modular approach is used for designing in-parallel manipulators. The optimum design of the platform and serial chains are obtained independently. The modules are then assembled into in-parallel manipulators according to the rules proposed in this work.

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Parallel Manipulators, towards New Applications

10.5772/61 ◽

2008 ◽

Cited By ~ 9

Keyword(s):

Parallel Manipulators ◽

New Applications

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6-DOF parallel manipulators with better dexterity, rotatability, or singularity-free workspace

Robotica ◽

10.1017/s0263574708004980 ◽

2009 ◽

Vol 27 (4) ◽

pp. 599-606 ◽

Cited By ~ 7

Author(s):

K. Y. Tsai ◽

T. K. Lee

Keyword(s):

Analytical Methods ◽

Degrees Of Freedom ◽

Parallel Manipulators ◽

Singular Points ◽

Symmetric Designs ◽

Kinematic Properties

SUMMARYIsotropic manipulators are generally considered as designs with optimum dexterity. Currently, many 6-DOF (degrees-of-freedom) isotropic parallel manipulators can be developed by numerical or analytical methods. At an isotropic configuration, a manipulator is equidistant from its neighboring singular points. The distance, however, can be very small, so an isotropic design might have relatively smaller singularity-free workspace. This paper presents methods to develop traditional 6-DOF parallel manipulators with better dexterity and larger singularity-free workspace. Some fully symmetric nontraditional designs are then proposed. The evaluation of kinematic properties shows that the fully symmetric designs have very good global dexterity, better rotatability, and relatively larger singularity-free workspace. The manipulators are suitable for some special tasks requiring higher precision, better rotatability, or larger workspace.

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1250-kilovolt scanning transmission electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113007 ◽

1984 ◽

Vol 42 ◽

pp. 624-625

Author(s):

T. Imura ◽

S. Maruse ◽

K. Mihama ◽

M. Iseki ◽

M. Hibino ◽

...

Keyword(s):

High Voltage ◽

Electron Probe ◽

Scanning Transmission Electron Microscope ◽

Pressure Vessels ◽

Practical Applications ◽

Voltage Generator ◽

Transmission Electron ◽

Scanning Transmission ◽

New Applications ◽

High Voltage Generator

Ultra high voltage STEM has many inherent technical advantages over CTEM. These advantages include better signal detectability and signal processing capability. It is hoped that it will explore some new applications which were previously not possible. Conventional STEM (including CTEM with STEM attachment), however, has been unable to provide these inherent advantages due to insufficient performance and engineering problems. Recently we have developed a new 1250 kV STEM and completed installation at Nagoya University in Japan. It has been designed to break through conventional engineering limitations and bring about theoretical advantage in practical applications.In the design of this instrument, we exercised maximum care in providing a stable electron probe. A high voltage generator and an accelerator are housed in two separate pressure vessels and they are connected with a high voltage resistor cable.(Fig. 1) This design minimized induction generated from the high voltage generator, which is a high frequency Cockcroft-Walton type, being transmitted to the electron probe.

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