Novel Design Method for Planar Four-Bar Mechanisms

WHAT

This project developed a fully algebraic method for predicting how a crank-slider mechanism will move based on its geometry. By replacing conventional, more complex trigonometric approaches with a simpler algebraic framework, we made it more efficient to predict a mechanism’s mobility directly from its link dimensions and slider position - before it is physically built.

WHY

Linkage design can involve significant trial and error, as small changes in geometry can completely alter a mechanism’s motion. We developed an algebraic design map that links dimensions directly to mobility, making it easier to work backwards from a desired motion to a viable mechanism geometry.

HOW

I helped develop a fully algebraic model for RRRP crank-slider mechanisms, using Python, MATLAB, and Maple to relate input-link rotation and slider displacement directly to mechanism geometry. I identified critical motion limits and classified each design as a crank, rocker, π-rocker, or 0-rocker. These relationships were then mapped into a 3D design space, creating a simpler way for engineers to select linkage dimensions based on the motion they want to achieve.

Workflow: Mechanism geometry → Algebraic model → Motion limits → Mobility classification → Design map

For more details, see publications: