An approach for mobility and force/motion transmissibility analysis of parallel mechanisms based on screw theory and CAD technology

Abstract

By integrating screw theory with computer-aided design (CAD) technology, this paper presents an effective and automated methodology for mobility and force/motion transmissibility analysis of parallel mechanisms (PMs). In this approach, A kinematic diagram of a PM termed as the conceptual model, which consists of a solid assembly and several skeleton elements in the form of datum entities and non-geometric entities such as parameters, equations and semantic information, is built by using the 3D modeling capabilities of SolidWorks. For each limb of the PM, a rule-based reasoning (RBR) system is developed based upon the dual and reciprocal properties of screw systems, allowing its own twist/wrench subspaces to be determined automatically by using the joint axis features extracted from the conceptual model. These considerations lead to an automated procedure that can be used to generate the general Jacobian of PMs, allowing the mobility and force/motion transmissibility analysis to be carried out automatically, a work that had to be done manually in the past. Based on the proposed approach, a software package is developed and examples are given to verify its effectiveness.