Optimization Design of a 2-DOF Compliant Parallel Mechanism Using NSGA-II Algorithm for Vibration-Assisted Milling

Compliant parallel mechanisms (CPMs) combining parallel mechanisms and compliant mechanisms exhibiting many advantages such as high stiffness, high load carrying capacity, and high accuracy are widely used in various precision engineering applications. This chapter proposes a new design of a CPM using hollow flexural hinges combined with semicircular hinges and leaf springs for a non-resonant vibration assisted milling application. The mechanism will be actuated by piezoelectric actuators. The dimensions of the mechanism are optimized using an FEA-based global search evolutionary optimization (NSGA-II) procedure, aiming to maximize the natural frequencies and decoupling between its two axes. The optimization procedure is programmed in MATLAB whereas the ANSYS Mechanical ADPL code is embedded to support and enhance the calculation process. Using the optimal parameters, the established model for the mechanical performance evaluation of the CPM is verified with the finite-element method. A prototype of the mechanism can be fabricated using wire EDM machining method and it will be incorporated into a CNC machining center to validate the performance of the established system.