Software for Investigating the Kinematics, Statics and Dynamics of Coupler-Driven Four-Bars for Two Position Synthesis

The synthesis of a planar four-bar in which a point on the coupler reaches two specified points and orientations generates a six-fold space of solutions. The solution space increases if additional links are added to drive the mechanism, such as the Stephenson III. This paper presents an investigation of a coupler driven four-bar linkage, a Stephenson III six-bar with an RPR chain driving the four-bar sub-chain instead of the classically defined 3R chain. The software allows the designer to specify the problem and quickly scan the solution space. A comparison is constructed between a four-bar driven through a torque at the input link and a coupler-driven four-bar. Changes in branch points, the joint force index and the dynamics are observed.