KINESTATIC ANALYSIS OF GENERAL PARALLEL MANIPULATORS

Robotic mechanisms in general can be of either serial-chain, parallel- chain, or hybrid (a combination of both parallel and serial chains) ge ometry. While it can be asserted that kinematic theories and technique s are well established for fully serial-chain manipulators, the same a ssertion cannot be made when it is considered in the general context. In this article, we present a general procedure for systematic formula tion and characterization of the instantaneous kinematics for a roboti c mechanism with a general parallel-chain geometry. A kinestatic appro ach based on screw system theory is adopted in this treatment. The res ulting equation is a compact Jacobian matrix of the system which inclu des attributes from not only the active joints but also the passive co nstraints An example has been provided to demonstrate the methodology as well as its theoretical feasibility.