KINEMATIC ANALYSIS AND SYNTHESIS OF 3-INPUT, 8-BAR MECHANISMS DRIVEN BY RELATIVELY SMALL CRANKS

Approximate kinematic equations are developed for the analysis and des ign of three-input, eight-bar mechanisms driven by relatively small cr anks. Application of a method in which an output link is presumed to c omprise a mean and a perturbational motion, along with the vector loop approach, facilitates derivation of the approximate kinematic equatio ns. The resulting constraint equations are, (i) in the form of a set o f four nonlinear equations relating the mean link orientations, and (i i) a set of four linear equations in the unknown perturbations (output link motions). The latter set of equations is solved, symbolically, t o obtain the output link motions. The approximate equations are shown to be effective in the synthesis of three-input, small-crank mechanism s.