The Stewart platform manipulator: a review

https://www-sop.inria.fr/coprin/PDF/merlet_mmt98.pdf

Workspaces of Planar Parallel Manipulators

We discuss the problem of minimum cost trajectory planning for robotic manipulators. It consists of linking two points in the operational space while minimizing a cost function, taking into account dynamic equations of motion as well as bounds on joint positions, velocities, jerks and torques. This generic optimal control problem is transformed, via a clamped cubic spline model of joint temporal evolutions, into a non-linear constrained optimization problem which is treated then by the Sequential Quadratic Programming (SQP) method. Applications involving grasping mobile object or obstacle avoidance are shown to illustrate the efficiency of the proposed planner.

Minimum cost trajectory planning for industrial robots

This article studies the kinematic design of different types of spherical three-degree-of-freedom parallel manipulators. The mechanical architectures presented have been introduced elsewhere. However, designs having at least one isotropic configuration are suggested here for the first time. Isotropic configurations are defined, in turn, as those configurations in which the Jacobian matrix, mapping the angular velocity vector of the effector into the joint velocities, is proportional to an orthogonal matrix. First, a review of the direct and inverse kinematics of spherical three-degree-of-freedom parallel manipulators is outlined, and a general form for the Jacobian matrix is given. Parallel manipulators with revolute or prismatic actuators are discussed. Then, the concept of kinematic conditioning is recalled and used as a performance index for the optimization of the manipulators. It is shown that this leads to designs having at least one isotropic configuration. Finally, a few examples of such designs are presented. 15 refs.

On the Kinematic Design of Spherical Three-Degree-of- Freedom Parallel Manipulators:

Analytical Methods in Vibrations

On the direct kinematics of spherical three-degree-of-freedom parallel manipulators of general architecture

Solutions polynomiales au probleme de la cinematique directe des manipulateurs paralleles plans a trois degres de liberte

Determination of the maximal singularity-free zones in the six-dimensional workspace of the general Gough-Stewart platform

Safety and comfort analysis of a 3-D vehicle model with optimal non-linear active seat suspension

The determination of the 6-D singularity locus of the general Gough-Stewart platform is discussed in this article. The derivation of the velocity equation and the corresponding Jacobian matrices is first presented. Then a new procedure is introduced to obtain the analytical expression of the singularity locus, which is a function of six variables (x, y, z, φ, θ, ψ), using the velocity equation. Examples are also given to illustrate the results obtained. Gough-Stewart platforms can be used in several robotic applications as well as in flight simulators. The determination of the singularity locus is a very important design and application issue.Copyright © 2004 by ASME

Marc J. Richard

Papers

On the direct kinematics of spherical three-degree-of-freedom parallel manipulators of general architecture

Solutions polynomiales au probleme de la cinematique directe des manipulateurs paralleles plans a trois degres de liberte

Determination of the maximal singularity-free zones in the six-dimensional workspace of the general Gough-Stewart platform

Safety and comfort analysis of a 3-D vehicle model with optimal non-linear active seat suspension

Analytic Form of the Six-Dimensional Singularity Locus of the General Gough-Stewart Platform