Simulation and integration of geometric and rigid body kinematics errors for assembly variation analysis

Rigid and compliant models have been developed in parallel in the literature for variation analysis of different assembly processes. For a complex assembly system, it is desirable to balance accuracy and simplicity by introducing a rigid-compliant hybrid model. This paper develops a new method aimed at providing an interface between rigid and compliant assembly models. Part geometric errors (PGE) and rigid body kinematics stackup error (RE) are simulated and integrated in rigid assembly processes. A covariance matrix of PGE and RE is then constructed, providing input to subsequent compliant assembly models. Algorithms are developed (1) to predict RE by using the stream of variation (SOVA) model; (2) to simulate PGE based on statistical modal analysis (SMA) and specified tolerances; and (3) to integrate RE and PGE in rigid assembly processes for covariance matrix construction. This is an initial step toward the development of a rigid-compliant hybrid assembly model for variation analysis in multistation manufacturing systems (MMS).