Coputer Simulation of Regular Walking Based on the Kinematic Analysis of Movements and the Synthesis of Exoskeleton Control Algorithms

The majority of the manipulation tasks requires the motion of the end effector from an initial pose to a final one without particular conditions on the path. Thus, the reduction of the practicable paths between two any poses is a possible choice, exploitable at the design stage, for simplifying manipulator’s hardware. This choice is adopted in under-actuated manipulators. The (nS)-2SPU wrist is one out of the under-actuated parallel wrists this author proposed in a previous paper. Here, the kinematic analysis of this wrist is studied. Both its finite and its elementary kinematics are considered. It is shown that its control algorithms can be written by using simple closed-form formulas, which can take advantage from the wide literature on spherical four-bar linkages. And the demonstration that its singular configurations can be avoided more easily than the ones of the fully-parallel wrist is provided.

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Kinematic Analysis of the (nS)-2SPU Underactuated Parallel Wrist

Journal of Mechanisms and Robotics ◽

10.1115/1.4006832 ◽

2012 ◽

Vol 4 (3) ◽

Cited By ~ 14

Author(s):

Raffaele Di Gregorio

Keyword(s):

Closed Form ◽

Kinematic Analysis ◽

Design Stage ◽

Control Algorithms ◽

End Effector ◽

Singular Configurations ◽

Underactuated Manipulators

The majority of the manipulation tasks require the motion of the end-effector from an initial pose to a final one without any particular condition on the path. Thus, the reduction of the practicable paths between any two poses is a possible choice, exploitable at the design stage, for simplifying the manipulator hardware. This choice is adopted in underactuated manipulators. The (nS)-2SPU wrist is one out of the underactuated parallel wrists this author proposed in a previous paper. Here, the kinematic analysis of this wrist is studied: both its finite and its elementary kinematics are considered. It is shown that its control algorithms can be written by using simple closed-form formulas, which can take advantage from the wide literature on the spherical four-bar linkages. Moreover, the demonstration that its singular configurations can be avoided more easily than the ones of the fully parallel wrist is provided.

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Kinematic Approximations in TED and RHEED Analysis of Reconstructed Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135587 ◽

1990 ◽

Vol 48 (2) ◽

pp. 396-397

Author(s):

L. -M. Peng ◽

M. J. Whelan

Keyword(s):

Electron Diffraction ◽

Kinematic Analysis ◽

Incident Beam ◽

High Energy ◽

Energy Electron ◽

Great Success ◽

High Energy Electron ◽

Kinematic Approximation ◽

Reconstructed Surfaces

In recent years there has been a trend in the structure determination of reconstructed surfaces to use high energy electron diffraction techniques, and to employ a kinematic approximation in analyzing the intensities of surface superlattice reflections. Experimentally this is motivated by the great success of the determination of the dimer adatom stacking fault (DAS) structure of the Si(111) 7 × 7 reconstructed surface.While in the case of transmission electron diffraction (TED) the validity of the kinematic approximation has been examined by using multislice calculations for Si and certain incident beam directions, far less has been done in the reflection high energy electron diffraction (RHEED) case. In this paper we aim to provide a thorough Bloch wave analysis of the various diffraction processes involved, and to set criteria on the validity for the kinematic analysis of the intensities of the surface superlattice reflections.The validity of the kinematic analysis, being common to both the TED and RHEED case, relies primarily on two underlying observations, namely (l)the surface superlattice scattering in the selvedge is kinematically dominating, and (2)the superlattice diffracted beams are uncoupled from the fundamental diffracted beams within the bulk.

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