This paper focuses on parallel mechanisms (PMs) that can perform two translations and two rotations (2T2R). Two sufficient conditions for eliminating parasitic motion in 2T2R PMs are presented. A motion expression satisfying those two conditions is identified and several kinematic bonds containing that motion are found. To achieve symmetrical structures, a configurable platform that generates an instantaneous translation motion is presented, to which four limbs having identical structures are connected, leading to the construction of novel 2T2R PMs. Several designs that may have good practical values are identified and form a mechanism family. A typical mechanism is selected with its position model, workspace, singularity thoroughly investigated. Redundant limbs are added to eliminate the singularities, which then ensure the rotational capability. The proposed mechanisms have the advantages of identical limbs, no parasitic motion, and relatively high rotational capability, which can be used in several applications such as in five-axis machine.

References

References
1.
Huang
,
Z.
, and
Li
,
Q. C.
,
2002
, “
General Methodology for Type Synthesis of Symmetrical Lower-Mobility Parallel Manipulators and Several Novel Manipulators
,”
Int. J. Rob. Res.
,
21
(
2
), pp.
131
145
.
2.
Li
,
Q.
,
Huang
,
Z.
, and
Hervé
,
J.
,
2004
, “
M. Type Synthesis of 3R2T 5-DOF Parallel Mechanisms Using the Lie Group of Displacements
,”
IEEE Trans. Rob. Autom.
,
20
(
2
), pp.
173
180
.
3.
Gao
,
F.
,
Li
,
W.
,
Zhao
,
X.
,
Jin, Z.
, and
Zhao, H.
,
2002
, “
New Kinematic Structures for 2-, 3-, 4-, and 5-DOF Parallel Manipulator Designs
,”
Mech. Mach. Theory
,
37
(
11
), pp.
1395
1411
.
4.
Fang
,
Y.
, and
Tsai
,
L. W.
,
2002
, “
Structure Synthesis of a Class of 4-DoF and 5-DoF Parallel Manipulators With Identical Limb Structures
,”
Int. J. Rob. Res.
,
21
(
9
), pp.
799
810
.
5.
Kong
,
X.
, and
Gosselin
,
C. M.
,
2004
, “
Type Synthesis of 3T1R 4-DOF Parallel Manipulators Based on Screw Theory
,”
IEEE Trans. Rob. Autom.
,
20
(
2
), pp.
181
190
.
6.
Gogu
,
G.
,
2007
, “
Structural Synthesis of Fully-Isotropic Parallel Robots With Schönflies Motions Via Theory of Linear Transformations and Evolutionary Morphology
,”
Eur. J. Mech—A/Solids
,
26
(
2
), pp.
242
269
.
7.
Jin
,
Q.
, and
Yang
,
T. L.
,
2004
, “
Theory for Topology Synthesis of Parallel Manipulators and Its Application to Three-Dimension-Translation Parallel Manipulators
,”
ASME J. Mech. Des.
,
126
(
4
), pp.
625
639
.
8.
Kong
,
X.
, and
Gosselin
,
C. M.
,
2004
, “
Type Synthesis of Three-Degree-of-Freedom Spherical Parallel Manipulators
,”
Int. J. Rob. Res.
,
23
(
3
), pp.
237
245
.
9.
Liu
,
X. J.
,
Wang
,
J.
, and
Pritschow
,
G.
,
2005
, “
A New Family of Spatial 3-DoF Fully-Parallel Manipulators With High Rotational Capability
,”
Mech. Mach. Theory
,
40
(
4
), pp.
475
494
.
10.
Li
,
Q.
, and
Hervé
,
J. M.
,
2010
, “
1T2R Parallel Mechanisms Without Parasitic Motion
,”
IEEE Trans. Rob.
,
26
(
3
), pp.
401
410
.
11.
Gan
,
D.
,
Dai
,
J. S.
,
Dias
,
J.
,
Umer, R.
, and
Seneviratne, L.
,
2015
, “
Singularity-Free Workspace Aimed Optimal Design of a 2T2R Parallel Mechanism for Automated Fiber Placement
,”
ASME J. Mech. Rob.
,
7
(
4
), p.
041022
.
12.
Li
,
Q.
, and
Huang
,
Z.
,
2003
, “
Type Synthesis of 4-DOF Parallel Manipulators
,”
IEEE International Conference on Robotics and Automation
(
ICRA
), Taipei, Taiwan, Sept. 14–19, pp.
755
760
.
13.
Gao
,
F.
,
Yang
,
J.
, and
Ge
,
Q. J.
,
2011
, “
Type Synthesis of Parallel Mechanisms Having the Second Class GF Sets and Two Dimensional Rotations
,”
ASME J. Mech. Rob.
,
3
(
1
), p.
011003
.
14.
Fan
,
C.
,
Liu
,
H.
, and
Zhang
,
Y.
,
2013
, “
Type Synthesis of 2T2R, 1T2R and 2R Parallel Mechanisms
,”
Mech. Mach. Theory
,
61
, pp.
184
190
.
15.
Kumar
,
N.
,
Piccin
,
O.
, and
Bayle
,
B.
,
2014
, “
A Task-Based Type Synthesis of Novel 2T2R Parallel Mechanisms
,”
Mech. Mach. Theory
,
77
, pp.
59
72
.
16.
Wang
,
C.
,
Fang
,
Y.
, and
Fang
,
H.
,
2015
, “
Novel 2R3T and 2R2T Parallel Mechanisms With High Rotational Capability
,”
Robotica
,
35
(
2
), pp.
401
418
.
17.
Ye
,
W.
,
Fang
,
Y.
,
Guo
,
S.
, and
Qu, H.
,
2014
, “
Type Synthesis of 2R2T Parallel Mechanisms Based on Motion Equivalent Chain Method
,”
Proc. Inst. Mech. Eng., Part C
,
228
(
17
), pp.
3209
3217
.
18.
Carretero
,
J. A.
,
Podhorodeski
,
R. P.
,
Nahon
,
M. A.
, and
Gosselin, C. M.
,
2000
, “
Kinematic Analysis and Optimization of a New Three Degree-of-Freedom Spatial Parallel Manipulator
,”
ASME J. Mech. Des.
,
122
(
1
), pp.
17
24
.
19.
Hunt
,
K. H.
,
1983
, “
Structural Kinematics of in-Parallel-Actuated Robot-Arms
,”
ASME J. Mech. Transm., Autom. Des.
,
105
(
4
), pp.
705
712
.
20.
Herve
,
J. M.
,
1978
, “
Analyse Structurelle Des Mécanismes Par Groupe Des Déplacements
,”
Mech. Mach. Theory
,
13
(
4
), pp.
437
450
.
21.
Herve
,
J. M.
, and
Sparacino
,
F.
,
1991
, “
Structural Synthesis of ‘Parallel’ Robots Generating Spatial Translation
,” International Conference on Advanced Robotics (
ICAR
), Pisa, Italy, June 19–22, pp.
808
813
.
22.
Li
,
Q.
,
Huang
,
Z.
, and
Hervé
,
J. M.
,
2004
, “
Displacement Manifold Method for Type Synthesis of Lower-Mobility Parallel Mechanisms
,”
Sci. China Ser. E: Technol. Sci.
,
47
(
6
), pp.
641
650
.
23.
Lee
,
C. C.
, and
Hervé
,
J. M.
,
2010
, “
Generators of the Product of Two Schoenflies Motion Groups
,”
Eur. J. Mech.-A/Solids
,
29
(
1
), pp.
97
108
.
24.
Tsai
,
L. W.
,
1999
,
Robot Analysis and Design: The Mechanics of Serial and Parallel Manipulators
,
Wiley
, New York.
25.
Dasgupta
,
B.
, and
Mruthyunjaya
,
T. S.
,
1998
, “
Force Redundancy in Parallel Manipulators: Theoretical and Practical Issues
,”
Mech. Mach. Theory
,
33
(
6
), pp.
727
742
.
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