Spherically actuated platform manipulator

This article presents the inverse and forward pose and rate kinematics solutions for a novel 6-DOF platform manipulator, actuated by two base-mounted spherical actuators. The moving platform is connected to the fixed base by two identical spherical-prismatic-universal serial chain legs. The S-joint is active, and the remaining two joints in each chain are passive. An analytical solution is presented for the inverse pose problems, a semi-analytical solution is presented for the rate problems, and the numerical Newton–Raphson technique is employed to solve the forward pose problem. Unfortunately, the passive joint variables cannot be ignored in the kinematics solutions as they can for the Gough–Stewart platform. Examples are presented and hardware has been built, using two Rosheim Omni-Wrists on loan from NASA as the spherical actuators. © 2001 John Wiley & Sons, Inc.

[1]  N. Duke Perreira.  Motions, efforts, and actuations in constrained dynamic systems: A multilink closed chain example , 1999 .

[2]  Jorge Angeles,et al.  The kinematics of spatial double-triangular parallel manipulators , 1995 .

[3]  J. Michael McCarthy,et al.  Conditions for line‐based singularities in spatial platform manipulators , 1998 .

[4]  C. Innocenti,et al.  Forward Kinematics of the General 6–6 Fully Parallel Mechanism: An Exhaustive Numerical Approach Via a Mono-Dimensional-Search Algorithm , 1993 .

[5]  Francis L. Merat,et al.  Introduction to robotics: Mechanics and control , 1987, IEEE J. Robotics Autom..

[6]  Michael M. Stanisic,et al.  Symmetrically actuated double pointing systems: the basis of singularity-free robot wrists , 1990, IEEE Trans. Robotics Autom..

[7]  K. H. Hunt,et al.  Structural Kinematics of In-Parallel-Actuated Robot-Arms , 1983 .

[8]  Kyong Sei Lee,et al.  Design Optimization of a Three Degrees-of-Freedom Variable-Reluctance Spherical Wrist Motor , 1995 .

[9]  Kok-Meng Lee,et al.  Dynamic Modeling and Control of a Ball-Joint-Like Variable-Reluctance Spherical Motor , 1992, 1992 American Control Conference.

[10]  D. Stewart,et al.  A Platform with Six Degrees of Freedom , 1965 .

[11]  Charles F. Reinholtz,et al.  Closed-Form Inverse Kinematic Analysis of Variable-Geometry Truss Manipulators , 1992 .

[12]  L. W. Tsai,et al.  Robot Analysis: The Mechanics of Serial and Parallel Ma-nipulators , 1999 .

[13]  Robert L. Williams.  Forward and inverse kinematics of double universal joint robot wrists , 1991 .

[14]  M. M. Mikulas,et al.  Deployable controllable geometry truss beam , 1985 .

[15]  D. Howe,et al.  A novel spherical permanent magnet actuator with three degrees-of-freedom , 1998 .

[16]  Zhiming Ji,et al.  Identification of placement parameters for modular platform manipulators , 1999 .

[17]  C. Gosselin,et al.  Kinematic analysis and singularity representation of spatial five‐degree‐of‐freedom parallel mechanisms , 1997 .

[18]  Gordon R. Pennock,et al.  Forward Position Analysis of Two 3-R Robots Manipulating a Planar Linkage Payload , 1995 .

[19]  Robert L. Williams.  INVERSE KINEMATICS AND SINGULARITIES OF MANIPULATORS WITH OFFSET WRIST , 1999 .

[20]  Zhiming Ji,et al.  Identification of placement parameters for modular platform manipulators , 1999, J. Field Robotics.

[21]  M. Raghavan.  The Stewart platform of general geometry has 40 configurations , 1993 .