ANALYSIS AND CAD TOOLS FOR PARALLEL MANIPULATORS

The theoretical studies carried out in the laboratory have led to the development of visual interactive analysis tools which facilitate the study of planar, spherical and spatial parallel manipulators. These tools allow the geometric parameters to be varied at will and allow the workspace, the singularity loci and other properties such as the stiffness and the dexterity to be obtained interactively. They allow trajectories to be carried out by controlling the Cartesian or articular coordinates. The user can also visualize different assembly modes and branches (solutions to the direct and inverse kinematic problems).

First designed more than ten years ago on Sun workstations, several versions of these analysis tools have been developed since, the most recent version running on Windows XP and Linux. Note that a specific version for the analysis of flight simulators was developed for the company CAE Electronics Ltd.

Fig. 1: Example of an interactive graphic environment CAD tool for parallel manipulators. Click on the image to enlarge.

The following figures show the results obtained with the software.

Fig. 2: Workspace boundary and dexterity curve in the plane for a spherical manipulator with prismatic actuators.

Fig. 3: Workspace of the Gough-Stewart platform. The workspace boundary is determined using an analytical expression obtained from a geometric analysis. The calculation takes but a few milliseconds.

Fig. 4: 3 Dimensional workspace for a spherical manipulator with prismatic actuators.

Fig. 5: Superposition of the workspace (green curves) and the singularity loci (red curves) for the Gough-Stewart platform. This superposition indicates that singularities are present in the workspace. Tools have been developed in the laboratory to detect the presence of singularities in the workspace and provide a guaranteed answer. Note also that the workspace and singularity loci are determined analytically. The calculation and display are carried out in but a few milliseconds.

Poster

A poster was prepared in 2002 for the analysis software for parallel manipulators. This poster can be downloaded by clicking on the PDF file below.

Software Tool for the Analysis, Design and Visualization of Robots (820 kb)