Although bevel-gear robotic wrists are widely used in industrial manipulators due to their simple kinematics and low manufacturing cost, their gear trains function under rolling and sliding, the latter bringing about noise and vibration. Sliding is inherent to the straight teeth of the bevel gears of these trains. Moreover, unavoidable backlash introduces unmodeled dynamics, which mars robot performance. To alleviate these drawbacks, a gearless pitch-roll wrist is currently under development for low backlash and high stiffness. The wrist consists of spherical cam-rollers and spherical Stephenson linkages, besides two roller-carrying disks that drive a combination of cams and Stephenson mechanisms, the whole system rotating as a differential mechanism. The paper focuses on the design of the chain of spherical Stephenson mechanisms. The problem of the dimensional synthesis is addressed, and interference avoidance is discussed. An embodiment of the concept is also included.
1.
Howard
, R. D.
, 2002, “Design of a Robotic Wrist and Tool-Exchange Mechanism for Satellite Servicing
,” Proc. 36th Aerospace Mechanism Symposium
, NASA Glenn Research Center
. The PDF file of this reference was downloaded from: http://www.ssl.umd.edu/publications/http://www.ssl.umd.edu/publications/. Unfortunately, this file does not include place and page numbers.2.
Yang
, D. C. H.
, Lin
, E. Y.
, and Cheng
, S. Y.
, 1990, “Primary Workspace of Industrial Robots With Roll-Pitch-Yaw Wrists
,” ASME J. Mech. Des.
1050-0472, 112
(3
), pp. 347
–353
.3.
Rauchfuss
, J. W.
, and Yang
, D. C. H.
, 2000, “A Geometric Approach for Determining Exact Point Accessibility of Robotic Manipulations
,” ASME J. Mech. Des.
1050-0472, 122
(3
), pp. 287
–293
.4.
Tsai
, L.-W.
, 1988, “The Kinematics of Spatial Robotic Bevel-Gear Trains
,” IEEE J. Rob. Autom.
0882-4967, 4
(2
), pp. 150
–156
.5.
Yang
, D.
, and Rauchfuss
, J.
, 2001, “A New Zero-Dimension Robot Wrist: Design and Accessibility Analysis
,” Int. J. Robot. Res.
0278-3649, 20
(2
), pp. 163
–173
.6.
Gosselin
, C. J.
, and Cloutier
, L.
, 1993, “The Generating Space for Parabolic Motion Error Spiral Bevel Gears Cut by Gleason Method
,” ASME J. Mech. Des.
1050-0472, 115
(3
), pp. 483
–489
.7.
Wiitala
, J. M.
, and Stanisic
, M. M.
, 2000, “Design of an Overconstrained and Dextrous Spherical Wrist
,” ASME J. Mech. Des.
1050-0472, 122
(3
), pp. 347
–353
.8.
Bidault
, F.
, Teng
, C. P.
, and Angeles
, J.
, 2001, “Structural Optimization of a Spherical Parallel Manipulator Using a Two-Level Approach
,” Proc. of ASME 2001 Design Engineering Technical Conferences
, DAC-21030.9.
Gosselin
, C.
, and Hamel
, J.-F.
, 1994, “The Agile Eye: A High-Performance Three-Degree-of-Freedom Camera-Orienting Device
,” Proc. IEEE Int. Conf. on Robotics and Automation
, pp. 781
–786
.10.
Ghuneim
, T.
, Angeles
, J.
, and Bai
, S.
, 2004, “The Design of a Novel Pitch-Roll Wrist With Spherical Cam-Roller Pairs
,” in On Advances in Robot Kinematics
J.
Lenarcic
and C.
Galletti
, eds., Kluwer Academic Publishers
, Dordrecht
, pp. 381
–388
.11.
Gonzlez-Palacios
, M.
, and Angeles
, J.
, 1999, “The Design of a Novel Mechanical Transmission for Speed Reduction
,” ASME J. Mech. Des.
1050-0472, 121
(4
), pp. 538
–543
.12.
Gonzlez-Palacios
, M.
, and Angeles
, J.
, 2003, “The Design of a Novel Pure-Rolling Transmission to Convert Rotational into Translational Motion
,” ASME J. Mech. Des.
1050-0472, 125
(1
), pp. 205
–207
.13.
Primrose
, E.
, Freudenstein
, F.
, and Roth
, B.
, 1967, “Six-Bar Motion. II. The Stepenson-1 and Stephenson-2 Mechanism
,” Arch. Ration. Mech. Anal.
0003-9527, 24
, pp. 42
–72
.14.
Suh
, C. H.
, and Mecklenburg
, A. W.
, 1973, “Optimal Design of Mechanisms With the use of Matrices and Least Squares
,” Mech. Mach. Theory
0094-114X, 8
(4
), pp. 479
–495
.15.
McLarnan
, C.
, 1963, “Synthesis of Six-Link Plane Mechanisms by Numerical Analysis
,” ASME J. Eng. Ind.
0022-0817, 85
(1
), pp. 5
–11
.16.
Zanganeh
, K. E.
, and Angeles
, J.
, 1993, “A Symbolic Approach to the Input-Output Analysis of the Stephenson Six-Bar Linkage
,” Proc. 1993 ASME Design Engineering Technical Conferences
, Albuquerque, Sept. 19–22, Vol. 2
, pp. 67
–72
.17.
Baker
, J. E.
, 2004, “The Closure Modes of Bennett’s Twelve-Bar Planar Linkage
,” ASME J. Mech. Des.
1050-0472, 126
(3
), pp. 464
–469
.18.
Dhingra
, A.
, Cheng
, J.
, and Kohli
, D.
, 1996, “Synthesis of Six-Link, Slider-Crank and Four-Link Mechanisms for Function, Path and Motion Generation Using Homotopy With m-Homogenization
,” ASME J. Mech. Des.
1050-0472, 116
(4
), pp. 1122
–1131
.19.
Schreiber
, H.
, Meer
, K.
, and Schmitt
, B. J.
, 2002, “Dimensional Synthesis of Planar Stephenson Mechanisms for Motion Generation Using Circlepoint Search and Homotopy Methods
,” Mech. Mach. Theory
0094-114X, 37
(7
), pp. 717
–737
.20.
Sakamoto
, Y.
, Ogawa
, K.
, and Funabashi
, H.
, 1994, “A Kinematic Analysis of Planar Six-Bar Mechansims With Consideration of the Interference of Moving Links
,” Mech. Mach. Theory
0094-114X, 29
(3
), pp. 345
–356
.21.
Chiang
, C.
, 1988, Kinematics of Spherical Mechanism
, Cambridge University Press
, Cambridge
.22.
Kohli
, D.
, and Khonji
, A.
, 1994, “Grashof-type of Rotatability Criteria of Spherical Five-Bar Linkages
,” ASME J. Mech. Des.
1050-0472, 118
(3
), pp. 99
–104
.23.
Farhang
, K.
, and Zargar
, Y.
, 1999, “Design of Spherical 4R Mechanisms: Function Generation for the Entire Motion Cycle
,” ASME J. Mech. Des.
1050-0472, 121
(12
), pp. 521
–528
.24.
Ge
, Q. J.
, and McCarthy
, J. M.
, 1991, “The Algebraic Classification of the Image Curves of Spherical Four-Bar Motion
,” ASME J. Mech. Des.
1050-0472, 113
(3
), pp. 227
–231
.25.
Ge
, Q. J.
, and Larochelle
, P. M.
, 1999, “Algebraic Motion Approximation With NURBS Motions and its Application to Spherical Mechanism Synthesis
,” ASME J. Mech. Des.
1050-0472, 121
(12
), pp. 529
–532
.26.
Larochelle
, P. M.
, and McCarthy
, J.
, 1994, “Design of Spatial 4C Mechanisms for Rigid-Body Guidance
,” Proc. 23rd Biennial Mechanisms Conference
, Minneapolis, Sept. 11–14, Vol. 70
, pp. 135
–142
.27.
Wampler
, C. W.
, 2004, “Displacement Analysis of Spherical Mechanisms Having Three or Fewer Loops
,” ASME J. Mech. Des.
1050-0472, 126
(1
), pp. 93
–100
.28.
Salmon
, G.
, 1885, Lessons Introductory to the Modern Higher Algebra
, Chelsea Publishing Co.
, New York
.29.
Angeles
, J.
, and Zakhariev
, E.
, 1998, Computational Methods in Mechanical Systems
, Springer-Verlag
, Heidelberg
.30.
Zanganeh
, K. E.
, and Angeles
, J.
, 1994, “On the Optimum Design of Planar and Spherical Drag-Link Mechanisms
,” ASME Journal of Mechanism Syntheis and Analysis
, 70
(4
), pp. 183
–190
.31.
Gosselin
, C.
, and Angeles
, J.
, 1989, “Optimization of Planar and Spherical Function Generators as Minimum-Defect Linkages
,” Mech. Mach. Theory
0094-114X, 24
(4
), pp. 293
–307
.Copyright © 2006
by American Society of Mechanical Engineers
You do not currently have access to this content.
