Issues in geometric synthesis of mechanisms

The paper presents a systematic non-iterative procedure for a priory design of link shapes for interference-free motion of a planar mechanism. We define the notions of unilayer and multi-layer links and show that generality of shapes that can be conceived depends upon the designer's choice about the physical implementation of the joints. We propose a matrix-based procedure for the determination of the nature of interaction among the links and joints during motion where each link can be multi-layer. Techniques for geometric synthesis as in the case of unilayer links could then be used by processing one layer at a time. The concept is demonstrated for the geometric synthesis of a six-bar Stephenson mechanism with one multi-layer link. A theory of simultaneous synthesis, using the concept of compliant motion, is also presented which does not have the limitations of order dependence inherently present in sweep-based methods