Effects of dimensional errors on compliant mechanisms performance by using dynamic splines

The paper deals with the description of a methodology for investigating the effects of the dimensional errors on the performance of compliant assemblies in order to perform an optimal allocation of tolerances. The proposed approach is based on the modeling of flexible elements using the dynamic spline formulation which is able to take into account the nonlinear compliance of the system using a small set of parameters. Starting from the description of the elasto-kinematic behavior of the system written in terms of Lagrange equations, the deduction of sensitivity coefficients is discussed and an algorithmic description of the tolerance allocation scheme is presented. In order to give an example of application, the methodology has been successfully applied to the optimization of a constant-force compliant mechanism.