Instantaneous Kinematics of General Hybrid Parallel Manipulators

Abstract

In this paper, we introduce a new class of parallel manipulators, called general hybrid parallel manipulators (GHPM). These are modular manipulators that may contain serial subchains as well as subchains of parallel modules, acting in parallel and connecting a base to a common platform. The instantaneous motion of the GHPM is studied by resorting to the theory of screws. In this context, we define the screw-system annihilator to reduce, systematically, the number of unknowns involved to a minimum. The formulation presented here is general and can be applied to most existing parallel manipulators, multifingered hands, multiple coordinated robots and walking machines. To illustrate the basic symbolical and numerical aspects of the proposed procedure, the analyses of the instantaneous kinematics of two hybrid manipulators are included.