Searching for undiscovered planar straight-line linkages

Abstract

In this paper we investigate if there are undiscovered 6-bar linkages for generating a straight-line. First we successfully deduce the relationships in Hart's second straight-line mechanisms using symbolic methods. For more complicate cases, we formulate the problem as precision position synthesis problems, and solve the derived equations using classic iterative methods and verify solutions using interval methods. Although no new mechanisms have been found at the current stage, this research initiates an e ort towards an automatic approach for obtaining over-constrained linkages (Dai and Rees Jones, 1999).