This paper presents methods to exploit the redundancy of a kinematically redundant spatial parallel mechanism with three redundant DOFs. The architecture of the mechanism is similar to the well-known Gough–Stewart (GS) platform and it retains its advantages, i.e., the members connecting the base to the moving platform are only subjected to tensile/compressive loads. The kinematic redundancy is exploited to avoid singularities and extend the rotational workspace. The architecture is described and the associated kinematic relationships are presented. Solutions for the inverse kinematics are given, as well as strategies to take into account the limitations of the mechanism such as mechanical interferences and velocity limits of the actuators while controlling the redundant degrees-of-freedom.

References

1.
Advani
,
S.
,
Nahon
,
M.
,
Haeck
,
N.
, and
Albronda
,
J.
,
1999
, “
Optimization of Six-Degrees-of-Freedom Motion Systems for Flight Simulators
,”
J. Aircr.
,
36
(
5
), pp.
819
826
.
2.
Lin
,
L.-C.
, and
Tsay
,
M.-U.
,
2000
, “
Modeling and Control of Micropositioning Systems Using Stewart Platforms
,”
J. Rob. Syst.
,
17
(
1
), pp.
17
52
.
3.
Pierrot
,
F.
,
Reynaud
,
C.
, and
Fournier
,
A.
,
1990
, “
Delta: A Simple and Efficient Parallel Robot
,”
Robotica
,
8
(
2
), pp.
105
109
.
4.
Charles
,
P. A.
,
1995
, “
Octahedral Machine Tool Frame
,” U.S. Patent No. 5,392,663.
5.
Pittens
,
K. H.
, and
Podhorodeski
,
R. P.
,
1993
, “
A Family of Stewart Platforms With Optimal Dexterity
,”
J. Rob. Syst.
,
10
(
4
), pp.
463
479
.
6.
Zanganeh
,
K. E.
, and
Angeles
,
J.
,
1997
, “
Kinematic Isotropy and the Optimum Design of Parallel Manipulators
,”
Int. J. Rob. Res.
,
16
(
2
), pp.
185
197
.
7.
Yun
,
Y.
, and
Li
,
Y.
,
2010
, “
Design and Analysis of a Novel 6-DOF Redundant Actuated Parallel Robot With Compliant Hinges for High Precision Positioning
,”
Nonlinear Dyn.
,
61
(
4
), pp.
829
845
.
8.
Merlet
,
J.-P.
,
1996
, “
Redundant Parallel Manipulators
,”
Lab. Rob. Autom.
,
8
(
1
), pp.
17
24
.
9.
Gosselin
,
C.
, and
Angeles
,
J.
,
1990
, “
Singularity Analysis of Closed-Loop Kinematic Chains
,”
IEEE Trans. Rob. Autom.
,
6
(
3
), pp.
281
290
.
10.
Merlet
,
J.-P.
,
1989
, “
Singular Configurations of Parallel Manipulators and Grassmann Geometry
,”
Int. J. Rob. Res.
,
8
(
5
), pp.
45
56
.
11.
Bonev
,
I.
,
2003
, “
The True Origins of Parallel Robots
,” Parallemic, Montreal, QC, Canada, accessed Jan. 2, 2018, http://www.parallemic.org/Reviews/Review007.html
12.
Gough
,
V.
, and
Whitehall
,
S.
,
1962
, “
Universal Tyre Test Machine
,”
FISITA Ninth International Technical Congress
, London, Apr. 30–May 5, pp.
117
137
.
13.
Gosselin
,
C.
, and
Schreiber
,
L.-T.
,
2018
, “
Redundancy in Parallel Mechanisms: A Review
,”
ASME Appl. Mech. Rev.
,
70
(
1
), p.
010802
.
14.
Gosselin
,
C.
,
Laliberté
,
T.
, and
Veillette
,
A.
,
2015
, “
Singularity-Free Kinematically Redundant Planar Parallel Mechanisms With Unlimited Rotational Capability
,”
IEEE Trans. Rob.
,
31
(
2
), pp.
457
467
.
15.
Schreiber
,
L.-T.
, and
Gosselin
,
C.
,
2017
, “
Kinematically Redundant Planar Parallel Mechanisms: Kinematics, Workspace and Trajectory Planning
,”
Mech. Mach. Theory
,
119
, pp.
91
105
.
16.
Gosselin
,
C.
, and
Schreiber
,
L.-T.
,
2016
, “
Kinematically Redundant Spatial Parallel Mechanisms for Singularity Avoidance and Large Orientational Workspace
,”
IEEE Trans. Rob.
,
32
(
2
), pp.
286
300
.
17.
Merlet
,
J.-P.
,
2006
,
Parallel Robots
, 2nd ed., Vol.
128
,
Springer
, Dordrecht,
The Netherlands
.
18.
Chiaverini
,
S.
,
1997
, “
Singularity-Robust Task-Priority Redundancy Resolution for Real-Time Kinematic Control of Robot Manipulators
,”
IEEE Trans. Rob. Autom.
,
13
(
3
), pp.
398
410
.
19.
Nakamura
,
Y.
,
Hanafusa
,
H.
, and
Yoshikawa
,
T.
,
1987
, “
Task-Priority Based Redundancy Control of Robot Manipulators
,”
Int. J. Rob. Res.
,
6
(
2
), pp.
3
15
.
20.
Tandirci
,
M.
,
Angeles
,
J.
, and
Ranjbaran
,
F.
,
1992
, “
The Characteristic Point and the Characteristic Length of Robotic Manipulators
,” ASME 22nd Biennial Mechanisms Conference, Scottsdale, AZ, Sept. 13–16, pp. 203–208.
21.
Lin
,
C.-C.
, and
Chang
,
W.-T.
,
2002
, “
The Force Transmissivity Index of Planar Linkage Mechanisms
,”
Mech. Mach. Theory
,
37
(
12
), pp.
1465
1485
.
22.
Sutherland
,
G.
, and
Roth
,
B.
,
1973
, “
A Transmission Index for Spatial Mechanisms
,”
J. Eng. Ind.
,
95
(
2
), pp.
589
597
.
23.
Cardou
,
P.
,
Bouchard
,
S.
, and
Gosselin
,
C.
,
2010
, “
Kinematic-Sensitivity Indices for Dimensionally Nonhomogeneous Jacobian Matrices
,”
IEEE Trans. Rob.
,
26
(
1
), pp.
166
173
.
24.
Lu
,
T.-T.
, and
Shiou
,
S.-H.
,
2002
, “
Inverses of 2 x 2 Block Matrices
,”
Comput. Math. Appl.
,
43
(
1
), pp.
119
129
.
25.
St-Onge
,
B. M.
, and
Gosselin
,
C. M.
,
2000
, “
Singularity Analysis and Representation of the General Gough-Stewart Platform
,”
Int. J. Rob. Res.
,
19
(
3
), pp.
271
288
.
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