Topology Optimization of Micro-robotic Appendages Combining Piezoelectric, Polymer, and Silicon Beams

A topology optimization approach is proposed for design of micro-robotic appendages containing active, passive compliant, and rigid beam elements. These elements represent materials and structures - thin-film piezoelectric actuators, parylene-C polymer microstructures, and silicon beams - that have recently been co-fabricated in prototype millimeter scale walking robots. Topology optimization is performed using design synthesis methods that prune an initial network of beams while converting passive compliant beams to active or rigid links using discrete variables. Sample optimization function is introduced for maximizing displacement in two directions subject to certain load bearing constraints. Controllability of multi-direction motion is also optimized through activation of separate piezoelectric elements. Sample design results generated by the proposed algorithm are presented.