Application of screw theory to motion analysis of assemblies of rigid parts

Screw theory is well known to do kinematic computations. Recently it has been used to create kinematic models of assembly features so allowing assembly analysis. Motion limit analysis uses the mathematics of screw theory to model the ability of mechanical assembly features to allow or constrain rigid body motions in six degrees of freedom. A user of this theory is able to determine the directions and quantitative amounts of possible finite rigid body motions of a part that is being added to an assembly via calculation applied to a defined set of assembly features. The ability to calculate rigid body motions of a part is important for enabling in-process adjustment during assembly to precisely establish key assembly dimensions. MLA software is a part of a suite of software programs used to do assembly analysis.