CLOSED-FORM DIRECT DISPLACEMENT ANALYSIS OF A 6-6 STEWART PLATFORM

The direct displacement analysis of a class of 6-6 Stewart platforms is considered here. Even though this is not the most general possible configuration, it has many of the advantages of the general configuration, and includes several useful arrangements that are of practical significance. The analysis leads to closed-form, decoupled polynomial equations (a quartic and two quadratics) of overall degree equal to sixteen. Since the largest degree polynomial is a quartic, no iterative schemes are required during the analysis. Finally, it is shown that only a few of the sixteen configurations have to be solved for algebraically, and the other configurations can be generated by geometric reasoning.