| Volume 24 Issue 5 - Publication Date: 1 May 2005 |
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| Fully Isotropic Four-Degrees-of-Freedom
Parallel Mechanisms for Schoenflies Motion |
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| M. Carricato DIEM
– Department of Mechanical Engineering, University of Bologna, Viale
Risorgimento 2, 40136 Bologna, Italy |
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| This paper presents a novel
family of fully isotropic parallel mechanisms whose output link is provided
with Schoenflies motion, i.e., it can freely translate in space and rotate
about a fixed direction. A methodology is proposed that makes use of the
theory of screws to synthesize desired forms for both the direct and the
inverse Jacobian matrices. In particular, these are made diagonal and constant
throughout the workspace. Motors are mounted one per leg and each one of
them actuates one of the degrees of freedom of the output body through a
constant one-to-one velocity relation. As a consequence, motors may apply,
with equal ease, a twist or a wrench of any amplitude (within the motor
operation range) to the end-effector around any screw congruous with the
admitted motion, so that full isotropy is achieved. Kinematic analysis is
trivial and no computation is required for real-time control. Furthermore,
actuator motion ranges can be easily related to the theoretical workspace
dimensions and the problem of link interference is potentially simplified. |
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| Multimedia Key |
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= Image |
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Extension |
Type |
Description |
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Example One:
Model of Figure 7(a) in motion (MP4
- 0.6MB or MOV
- 0.6MB). |
2 |
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Example Two: Model of
Figure 7(b) in motion (MP4
- 0.6MB or MOV
- 0.6MB). |
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