Kinetostatic modeling of parallel mechanisms with a passive constraining leg and revolute actuators

This paper introduces several new types of parallel mechanisms with revolute actuators whose degree of freedom (dof) is dependent on a constraining passive leg connecting the base and the platform. A general kinetostatic model is established for the analysis of the structural rigidity and accuracy of this family of mechanisms. The geometric model of this class of mechanisms is first introduced. Then, a lumped kinetostatic model is proposed in order to account for joint and link compliances. Additionally, the inverse kinematics and velocity equations are given for both rigid-link and flexible-link mechanisms. Finally, a few examples are given to illustrate the results.