Mobility Conditions for Planar Linkages Using Triangle Inequality and Graphical Interpretation

The triangle inequality concept is utilized in formulating the mobility conditions for a planar four-bar linkage. These conditions are used to investigate crank existence and mobility region for the linkage. More significantly, a manifest graphical interpretation is offered, enabling an expeditious mobility determination. A computer-aided graphics approach lends itself to relevant computations with greater speed and accuracy. The concept is further exemplified by means of a more complex planar linkage.