International audienceThis paper presents an important evolution in an optimization method, called FlexIn, developed for the optimal design of piezoelectric compliant micromechanisms. It is based on a flexible building block method that uses an evolutionary approach, to optimize a truss-like planar structure made of piezoelectric passive, active and now sensitive building blocks. The model of these blocks is established by means of a finiteelement electromechanical formulation. The main contribution of this paper is to present an new control-observation-oriented criterion considered in the optimization procedure, among other conventional mechanical criteria, to optimize modal observability of the structure, for the placement of piezoactuating and piezosensing parts. In order to point out the underlying interests of this method for the design of smart structures with integrated actuators and sensors, a planar piezoelectric compliant smart micro-mechanism is optimally synthesized. Simulations of the device are finally performed illustrating the role of the observation-oriented criterion in simplifying the control of such smart structures
