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Abstract: Wire-driven parallel kinematic manipulators (PKMs) have
advantageous characteristics in terms of weight, flexibility and
workspace compared with conventional leg-supported PKM. Based on
previous achievements, a novel six degrees of freedom (DOF) wire-driven
PKM with seven wires with compact size is presented. In the proposed
manipulator, one end of each wire is connected to the moving platform
with a spherical joint and the other end is connected to a pulley which
is driven by a servo motor. Based on the static model of the
manipulator, the survey of analysis of vector-closure based controllable
workspace by Kawamura, analysis of workspace with tension conditions and
workspace with stiffness conditions by Verhoeven is addressed. Finally,
a case study is presented to demonstrate the application of the
methodology to determine the controllable workspace and the workspace
with tension conditions and the workspace with stiffness conditions
using Monte-Carlo technique under the Matlab environment. The simulation
results show that the positional controllable workspace in z direction
of the 6-DOF wire-driven PKM is so large that it could be almost as long
as the entire system itself, but with a small rotational workspace. The
manipulator is also characteristic of better stiffness around the home
pose, but smaller tension limits. It also shows that the boundary of the
workspaces is still an open topic to be tackled. The near future works
include the kinematics synthesis of the manipulator. The manipulator can
be used in super large-scale robots.
Key words: Wire-driven PKM 6-DOF Controllable workspace Workspace
with tension conditions Workspace with stiffness conditions
CLC No: TH11
Received
20020830, received in revised form 20021110
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