Two-degree-of-freedom (2DOF) pointing mechanisms have been widely used in areas such as stabilized platforms, tracking devices, etc. Besides the commonly used serial gimbal structures, another two types of parallel pointing mechanisms, i.e., spherical parallel manipulators (SPMs) and equal-diameter spherical pure rolling (ESPR) parallel manipulators, are increasingly concerned. Although all these pointing mechanisms have two rotational DOFs, they exhibit very different motion characteristics. A typical difference existing in these three pointing mechanisms can be found from their characteristics of self-motion, also called spinning motion by the authors. In this paper, the spinning motions of three pointing mechanisms are modeled and compared via the graphical approach combined with the vector composition theorem. According to our study, the spinning motion is essentially one component of the moving platform's real rotation. Furthermore, image distortions caused by three spinning motions are identified and distinguished when the pointing mechanisms are used as tracking devices. Conclusions would facilitate the design and control of the pointing devices and potentially improve the measuring accuracy for targets pointing and tracking.

References

1.
Dunlop
,
G. R.
, and
Jones
,
T. P.
,
1999
, “
Position Analysis of a Two DOF Parallel Mechanism—The Canterbury Tracker
,”
Mech. Mach. Theory
,
34
(
4
), pp.
599
614
.
2.
Hilkert
,
J. M.
,
2008
, “
Inertially Stabilized Platform Technology: Concepts and Principles
,”
IEEE Control Syst. Mag.
,
28
(
2
), pp.
26
46
.
3.
Harrison
,
J. V.
,
Gallagher
,
J. L.
, and
Grace
,
E. J.
,
1971
, “
An Algorithm Providing All-Attitude Capability for Three-Gimbaled Inertial Systems
,”
IEEE Trans. Aerosp. Electron. Syst.
,
7
(
3
), pp.
532
543
.
4.
Gosselin
,
C. M.
, and
Hamel
,
J. F.
,
1996
, “
The Agile Eye: A High-Performance Three Degree-of-Freedom Camera-Orienting Device
,”
IEEE International Conference on Robotics and Automation
(
ICRA
),
San Diego
, CA, May 8–13, pp.
781
786
.
5.
Stanšić
,
M. M.
,
Wiitala
,
J. M.
, and
Feix
,
J. T.
,
2001
, “
A Dexterous Humanoid Shoulder Mechanism
,”
J. Rob. Syst.
,
12
(
18
), pp.
737
745
.
6.
Ruggiu
,
M.
,
2010
, “
Kinematic and Dynamic Analysis of a Two-Degree-of-Freedom Spherical Wrist
,”
ASME J. Mech. Rob.
,
3
(
2
), p.
031006
.
7.
Guo
,
W. Z.
,
Gao
,
F.
,
Deng
,
Y. C.
, and
Liang
,
Q. H.
,
2010
, “
The New Design of Stabilized Platform for Target Seekers Using Two-DOF Spherical Linkage
,”
Int. J. Des. Eng.
,
4
(
3
), pp.
337
354
.
8.
Rolland
,
L.
,
2013
, “
Efficiency Improvement of 2-DOF Sun Tracking for Preliminary Engineering Analysis
,”
3rd EIC Climate Change Technology Conference
(
CCTC 2013
),
Concordia University
,
Montreal, QC
, Canada, May 27-29, Paper No. 1560706569.
9.
Carricato
,
M.
,
2009
, “
Decoupled and Homokinetic Transmission of Rotational Motion Via Constant-Velocity Joints in Closed-Chain Orientational Manipulators
,”
ASME J. Mech. Rob.
,
4
(
1
), pp.
1
14
.
10.
Zeng
,
D. X.
,
Lu
,
W. J.
,
Zhang
,
C.
,
Chang
,
W.
, and
Hou
,
Y. L.
,
2013
, “
Design and Analysis of a Novel 2-DOF Rotational Decoupled Adjusting Parallel Mechanism
,”
IEEE International Conference on Industrial Informatics
(
INDIN
), Bochum, Germany, July 29–31, pp.
321
324
.
11.
Rosheim
,
M. E.
, and
Sauter
,
G. F.
,
2002
, “
New High-Angulation Omni-Directional Sensor Mount
,”
Proc. SPIE
,
4821
, pp.
163
174
.
12.
Wu
,
K.
,
Yu
,
J. J.
,
Zong
,
G. H.
, and
Kong
,
X.
,
2014
, “
A Family of Rotational Parallel Manipulators With Equal-Diameter Spherical Pure Rotation
,”
ASME J. Mech. Rob.
,
6
(
1
), p.
011008
.
13.
Kong
,
X.
,
2011
, “
Forward Displacement Analysis and Singularity Analysis of a Special 2-DOF 5R Spherical Parallel Manipulator
,”
ASME J. Mech. Rob.
,
3
(
2
), p.
024501
.
14.
Seherr-Thoss
,
H. C.
,
Schmelz
,
F.
, and
Aucktor
,
E.
,
2006
,
Universal Joints and Drive Shafts: Analysis, Design, Application
,
Springer
,
New York
.
15.
Castellet
,
A.
, and
Thomas
,
F.
,
1999
, “
Characterization of the Self-Motion Set of the Orthogonal Spherical Mechanism
,”
Mech. Mach. Theory
,
34
(
1
), pp.
59
88
.
16.
Yang
,
J. L.
, and
Gao
,
F.
,
2009
, “
Singularity Loci of an Orthogonal Spherical Two-Degree-of-Freedom Parallel Mechanism
,”
Front. Mech. Eng. China
,
4
(
4
), pp.
379
385
.
17.
Adolf
,
K.
,
2001
, “
Singularities and Self-Motions of Equiform Platforms
,”
Mech. Mach. Theory
,
36
(
7
), pp.
801
815
.
18.
Husty
,
M. L.
, and
Karger
,
A.
,
2002
, “
Self Motions of Stewart-Gough Platforms, an Overview
,”
Workshop on Fundamental Issues and Future Research Directions for Parallel Mechanisms and Manipulators
,
Quebec City, Canada
, Oct. 3–4, pp.
131
141
.
19.
Briot
,
S.
,
Arakelian
,
V.
,
Bonev
,
I. A.
,
Chablat
,
D.
, and
Wenger
,
P.
,
2008
, “
Self-Motions of General 3-RPR Planar Parallel Robots
,”
Int. J. Rob. Res.
,
27
(
7
), pp.
855
866
.
20.
Ho
,
T. H.
,
2007
, “
Pointing, Acquisition, and Tracking Systems for Free-Space Optical Communication Links
,”
Ph.D. dissertation
, University of Maryland, College Park, MD.
21.
Kong
,
X.
,
2010
, “
Forward Displacement Analysis of a 2-DOF RR-RRR-RRR Spherical Parallel Manipulator
,”
IEEE/ASME International Conference on Mechatronics and Embedded Systems and Applications
(
MESA
), Qindao, ShanDong, China, July 15–17, pp. 446–451.
22.
Rosheim
,
M. E.
, and
Sauter
,
G. F.
,
2003
, “
Free Space Optical Communication System Pointer
,”
Proc. SPIE
,
4975
, pp.
126
133
.
23.
Yu
,
J. J.
,
Dong
,
X.
,
Pei
,
X.
, and
Kong
,
X.
,
2012
, “
Mobility and Singularity Analysis of a Class of Two Degrees of Freedom Rotational Parallel Mechanisms Using a Visual Graphical Approach
,”
ASME J. Mech. Rob.
,
4
(
4
), p.
041006
.
24.
Dong
,
X.
,
Yu
,
J. J.
,
Chen
,
B.
, and
Zong
,
G. H.
,
2012
, “
Geometric Approach for Kinematic Analysis of a Class of 2-DOF Rotational Parallel Manipulators
,”
Chin. J. Mech. Eng.
,
25
(
2
), pp.
241
247
.
25.
Shabana
,
A. A.
,
2001
,
Computational Dynamics
,
Wiley
,
New York
.
26.
Shuster
,
M. D.
,
1993
, “
A Survey of Attitude Representations
,”
J. Astronaut. Sci.
,
41
(
4
), pp.
439
517
.
27.
Bonev
,
I. A.
,
2002
, “
Geometric Analysis of Parallel Mechanisms
,” Ph.D. dissertation, Laval University, Quebec, Canada.
28.
Zhang
,
L. J.
,
Niu
,
Y. W.
, and
Huang
,
Z.
,
2006
, “
Analysis of the Workspace of Spherical 2-DOF Parallel Manipulator With Actuation Redundancy
,”
IEEE International Conference on Mechatronics and Automation
(
ICMA
), Luoyang Henan, China, June 25–28, pp.
153
158
.
29.
Sofka
,
J.
,
2007
, “
New Generation of Gimbals Systems for Aerospace Applications
,”
Ph.D. dissertation
, Binghamton University, New York.
30.
Wu
,
Y. Q.
,
Li
,
Z. X.
, and
Shi
,
J. B.
,
2010
, “
Geometric Properties of Zero-Torsion Parallel Kinematics Machines
,”
IEEE/RSJ International Conference on Intelligent Robots and Systems
(
IROS
),
Taipei, Taiwan
, Oct. 18–21, pp. 2307–2312.
31.
Yu
,
J. J.
,
Yu
,
J. Z.
,
Wu
,
K.
, and
Kong
,
X.
,
2014
, “
Design of Constant-Velocity Transmission Devices Using Parallel Kinematics Principle
,”
ASME
Paper No. DETC2014-35013.
32.
Romero
,
L.
, and
Gomez
,
C.
,
2007
, “
Correcting Radial Distortion of Cameras With Wide Angle Lens Using Point Correspondences
,”
Scene Reconstruction, Pose Estimation and Tracking
,
In-Tech Education and Publishing
,
Rijeka
, Croatia, pp.
51
64
.
33.
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
.
34.
Liu
,
X. J.
, and
Bonev
,
I. A.
,
2008
, “
Orientation Capability, Error Analysis, and Dimensional Optimization of Two Articulated Tool Heads With Parallel Kinematics
,”
ASME J. Manuf. Sci. Eng.
,
130
(
1
), p.
011015
.
You do not currently have access to this content.