robot design for dexterous manipulationpowerpoint presentation author: divya haresh shah created...
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ROBOT DESIGN FOR DEXTEROUS MANIPULATIONDivya SHAH (PhD Student) ; Giorgio METTA (Vice Scientific Director) ; Alberto PARMIGGIANI (Technologist)
iCub Facility; Istituto Italiano di Tecnologia, Genova, ITALY
DESIRED WRIST CHARACTERISTICS
3. ORIENTATION WORKSPACE ANALYSIS
MECHANISMS
2. CAD-BASED APPROACH
1. MOTIVATION
September, 2018
In today’s times, it is essential for the humanoids to match up to the dexterity of thehumans. These skills contribute significantly in their capacities for feeling, exploring,learning, planning and subsequently acting. iCub Humanoid, developed at our facility, wasdesigned explicitly to promote research for the same. In this work, we focus on theenhancement of the wrist dexterity.
4. ISOTROPY ANALYSIS
1. 2DOF Gimbal MechanismSerial mechanism with the
desired behaviour. This is our point of reference.
2. 4-UU Mechanism4 identical limbs with mirror-symmetric architecture of
RRRR chains.
3. Spherical Six-Bar MechanismSix spherical linkages connected by R joints with a central gimbal.
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5. CONCLUSIONS
The mechanism isotropy is defined as follows; where ‘J’ are the Jacobianmatrices computed numerically from the simulation data and ‘m’ is the order ofthe task space:
GIMBAL 4-UU S6B
RO
LL
YA
WP
ITC
H
Compact Design
Higher Payload-to-Weight Ratio
Simpler Kinematics
Large Range of Motion
Regular/Symmetric Workspace
Full Pitch-Yaw Decoupling
01
02
03
04
05
06
ISO
TR
OP
Y
NEW WRIST
Work in Progress …
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Spherical Parallel Mechanism
Multibody Mechanism Simulation
Extract Workspace Measures
Contour Plots
CAD Model of the architecture
a) Warping in the Workspace: Mechanism behaviours are notsymmetric, i.e., the plots are not centered with absolute zero. Workspacediverges towards the extremes, as in case of 4-UU.
c) Asymmetric Parasitic Roll Motion: Platform posses undesiredRoll motion in case of 4-UU, which becomes difficult to becompensated. Central gimbal prevents the same for S6B.
b) Yaw-Pitch Coupling: Unlike gimbal, pitch and yaw contours are notstraight lines, i.e., the motions are coupled with each other and one inputproduces both outputs.
d) Anisotropy: Mechanisms are not fully isotropic throughout theworkspace. S6B best with Δ ≥ 0.9 for significantly large section of theworkspace.