Coupler-Point Curve Synthesis Using Homotopy Methods

Abstract

A new numerical method called "Homotopy" method (Continuation method) is applied to the problem of four-bar coupler-point-curve synthesis. We have shown that, for five precision points, the link lengths of a four-bar linkage can be found by the "General Homotopy" method. For nine precision points, the "Cheater's Homotopy" can be applied to find some four-bar linkages that will guide a coupler point through the nine prescribed positions. The nine-coupler points synthesis problem is highly non-linear and highly singular. We have also shown that Newton-Raphson's method and Powell's method, in general, tend to converge to the singular condition or do not converge at all, while the cheater's homotopy always works. The powerfulness of Cheater's homotopy opens a new frontier for dimensional synthesis of mechanisms.