Optimal design of robust piezoelectric unimorph microgrippers

• Systematic procedure to design piezoelectric actuated microgrippers. • Simultaneous optimization of the host structure and the polarization profile. • Out-of-plane bending produced is suppressed in some points of interest. • Control of the feature size through robust approach. • Minimization of target to small manufacturing errors. Topology optimization can be used to design piezoelectric actuators by simultaneous design of host structure and polarization profile. Subsequent micro-scale fabrication leads us to overcome important manufacturing limitations: difficulties in placing a piezoelectric layer on both top and bottom of the host layer. Unsymmetrical layer placement makes the actuator bend, spoiling the predicted performance of the device. The aim of this work is to maximize the in-plane displacement of a microgripper-type actuator while out-of-plane displacement at some points of interest is suppressed. This last issue is the main novelty introduced in this work, and the emphasis is placed on the modelling and its applicability rather than numerical methods. In addition, a robust formulation of the problem has been used in order to ensure minimum length scale in the optimal designs, which it is crucial from the manufacturability point of view.