Abstract:

This work presents a new methodology for fully compliant micro-mechanism design using continuum topological optimization method. The multi-objective optimization model is established by using compromise programming scheme, in which a kinematical function and a structural function are both applied to indicate the demands of mechanism flexibility and structure stiffness, and the sensitivities for compliant mechanism optimization design is performed by adopting the adjoint sensitivity analysis method. A new globally convergent method of moving asymptotes (GCMMA) is worked out based on the method of moving asymptotes (MMA) belonging to convex programming methods. Numerical instabilities occurring in resulting mechanism are also investigated and a modified SIMP density-stiffness interpolation scheme is suggested not only to eliminate checkerboards and mesh-dependency, but also to improve the one-node connected hinges. The typical application, a micro inverter mechanism, is employed to demonstrate the validation of the algorithms presented in this work. A procedure has been suggested to convert the topological optimization results to a CAD model, and the prototype has also been fabricated as the proof of concept design by laser manufacturing technology.

Key words: compliant mechanism, topological optimization, multi-objective optimization, the method of moving asymptotes, density filtering approach