Lever mechanisms: the new approach to structural synthesis and kinematic analysis

Abstract

There are two types of mechanisms mobility: structural and kinematic. Kinematic mobility can be divided into local and global mobilities. Kinematic mobility cannot be determined only thought the type and number of links and kinematic pairs; it is necessary to consider links locations and size dimensions. Mechanism scheme which presents its structure and kinematic mobility is called the structural-kinematic scheme. The developed methodology of structural-kinematic mechanism synthesis (including mechanisms with passive constraints) is described in the article. The set of structural units for the synthesis is created. The set includes basic one-link and two-link groups – main structural units. The number of structural unit types is optimal. Mobilities are: -1, 0, +1. The concept of “method of structural units fitting” was introduced in the article. Methods of unit fitting were arranged. The graphic basics of the design language for planar mechanism structural-kinematic scheme description were suggested. The graphic basics are to help designers define objectives of the mechanisms analysis and synthesis using computer methods, thus minimize labour in-put. The examples of mechanisms description by means of suggested graphic language were given alongside with the structural-kinematic scheme synthesis requirements and the stages of kinematic analysis.