Stability of a Four-Bar Linkage with Flexible Coupler

Abstract

The undamped transverse vibration of a flexible coupler in a crank and rocker four-bar linkage is shown to be governed by an inhomogeneous Hill's equation. Analysis of the corresponding homogeneous equation shows that the vibration may be unstable and that at a prescribed input speed stability depends on the inertia effects of the follower as well as on the characteristics of the coupler. Stability boundaries may be determined by digital computation, and an illustrative chart is worked out for a particular case.