Topology Optimization Applied to The Design of Linear Piezoelectric Motors

Topology optimization is a general computer design method applied to design optimal topology of structures that maximizes (or minimizes) a specified objective function (stiffness, for example) according to some constraints (such as volume). In this work, topology optimization is applied to design linear piezoelectric motors. These motors consist essentially of a flexible structure actuated by two or more piezoceramics excited with different phases. The actuated piezoceramics deform the flexible structure which moves due to friction over a fixed structure, called stator. The flexible structure acts as a mechanical transform by amplifying and changing the direction of the output displacement generated by piezoceramics. The objective is to develop a method which allows us to design systematically a flexible structure for a linear piezoelectric motor taking into account its performance for a given configuration of piezoceramics. This performance is related to the displacement generated in the motor moving direction and clamping force between the flexible structure and stator. Both quantities depend on the distribution of flexibility and stiffness in the flexible structure domain, which is related to its topology. By designing other types of flexible structures connected to the piezoceramics, novel types of linear piezoelectric motors can be obtained. Only quasi-static applications of motors are considered. The design of an “inchworm-type” piezoelectric motor is presented to illustrate the implementation of the method.