Abstract: The numerical comparison method is presented for planar four-bar linkage synthesis including function synthesis, path synthesis and guidance synthesis. The characteristics of four-bar, linkage coupler angle curve and side link angle curve, are analyzed. Conversion method is produced for three types four-bar linkage synthesis. The numerical comparison method can get a series results satisfied with design requirement for all the three types of linkage synthesis. The software based on this method will ask for the input of design requirements, and automatically select the optimum results from these available results. This method has be illustrated by computer simulation on mechanism kinematics.

Key words: Mechanism synthesis, Numerical comparison method, Planar four-bar linkage, Analysis of freedom degree, Combined location in non-coplanar planes, Geometry theorem, Location normal, Machine tool fixture design