On cam system design to replicate spatial four-bar mechanism coupler motion

Abstract

The coupler motion of a planar four-bar mechanism can be reproduced by rotating the mechanism's moving centrode over its fixed centrode. For spatial four-bar mechanisms, coupler motion can be replicated by moving the mechanism's moving axode over its fixed axode in a screw motion – a combination of simultaneous rotations and translations. This study presents a model to calculate the fixed and moving axodes of the revolute–revolute–spherical–spherical (RRSS) mechanism – one of the most basic spatial four-bar mechanisms. The axodes are useful in producing the contact surfaces for a cam system to replicate RRSS coupler motion.