Geometric Analysis and Optimization of a Symmetrical Watt Six-Bar Mechanism

Abstract

This paper describes the synthesis of a mechanism, with the aim of producing a virtual hinge device whose instantaneous centre varies in position as little as possible, and gives an analysis of the relative instantaneous centres of six bars that form a Watt six-bar linkage mechanism. A new expression of the three-centre theorem is successfully applied to the six-bar linkage mechanism by combining geometric representation with vector analysis. Based on this analysis, a formulation for optimization has been established, and the mechanism has been optimized to minimize the movement of the instantaneous centre of one of the bars. A dimensionless example is given.