This paper is organized as follows: section 2 is
devoted to a brief review of the kinematic analysis
to establish the notation. Based upon the equations
presented in section 2, the derivation of the two
Jacobians are carried out in section 3. In section 4,
the singularity analysis is presented. Section 5
introduces a simpler technique of identifying
singularities based upon intermediate Jacobians.
Section 6 concludes the article.