Synthesis of Seven-Bar Linkage with Two DOF for Body Guidance

Abstract

A linkage with seven links for the task of body guidance is proposed and evaluated. This linkage has two degrees of freedom and is consisted of a four-bar linkage, a dyad, and a floating link. The analysis reveals that at most eleven positions can be prescribed if the linkage is equipped with two actuators. The constituent four-bar linkage and the dyad can be separately synthesized by using well-developed techniques for synthesizing four-bar linkages. Each of them can satisfy five prescribed points together with four swing angles so that this seven-bar linkage can be driven by a single actuator after modification by adding gears. Problems of order defects, branch defects and ratios of link lengths are all considered to ensure the applicability of the synthesized linkages.