Kinematic Analysis and Design of Two-Input, Five-Bar Mechanisms Driven by Relatively Small Cranks

Abstract

Single-input mechanisms driven by relatively small cranks have been shown to have output link motions, describable as approximately simple harmonic functions of the input crank angular displacement. This paper presents a mathematical formulation for the approximate analysis and design of two-input, small-crank five-bar mechanisms for function generation. A perturbation technique is employed for the derivation of the approximate equations. Coefficients of the harmonic terms in the equations for an output link motion are obtained from the mechanism geometry and application of the perturbation technique. The output link motion is shown to be approximately described by a linear combination of two simple harmonic functions, in terms of the two input crank angles. Two mechanism design examples are presented to demonstrate the utility of the analytical development in the synthesis of five-bar mechanisms for function generation.