文档介绍：Mechanism and Machine Theory 44 (2009) 1032–1044
Contents lists available at ScienceDirect
Mechanism and Machine Theory
journal homepage: ate/mechmt
Determination of the kinematically redundant active prismatic joint
variable ranges of a planar parallel mechanism for singularity-free
trajectories
S.-H. Cha, . Lasky, . Velinsky *
Department of Mechanical and Aeronautical Engineering, University of California – Davis, One Shields Avenue, Davis, CA 95616, USA
article info abstract
Article history: Based on its simple structure, base-fixed actuators, high payload capacity, high accuracy,
Received 25 June 2007 and high mechanical rigidity, the 3-RRR mechanism1 is a practical planar parallel manipu-
Received in revised form 8 May 2008 lator. However, the 3-RRR mechanism is known to have singular loci within its workspace
Accepted 9 May 2008
affecting its use. A recent paper by these authors introduced a singularity avoidance algo-
Available online 24 June 2008
rithm for the 3-RRR mechanism using kinematic redundancy. This paper extends the earlier
work and allows for determination of the required ranges of the kinematically redundant
active prismatic joint variables of a mechanism to allow given trajectories to be singular-
Keywords:
ity-free. Since for a kinematically redundant mechanism the initial configuration is crucial
Robotics
Kinematic redundancy for redundancy resolution, the proposed algorithm uses permutations to consider all possible
Parallel manipulator points where kinematic redundancy resolution begins. The efficacy of the algorithm is dem-
Local optimization onstrated through simulation.
Mechanism design Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
It is well known that the 3-RRR mechanism is a practical planar parallel manipulator, since its structure is simple and the
actuators are fixed at the base, which reduces the inertia of the moving body. Also, as a parallel mechanism, it has high pay-
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