Design of a piezoelectric actuator and compliant mechanism combination for maximumenergy efficiency

Abstract

The combined optimization of a compliant mechanism and a piezoelectric stack actuatorfor maximum energy conversion efficiency is considered. The analysis assumes allcomponents to be free from dissipation and that the piezoelectric stack actuator is drivenby an ideal sinusoidal voltage source. The energy conversion efficiency is defined as theratio of the output mechanical energy to the input electric energy. Using linear two-portmodels, an analytical expression for the maximum energy conversion efficiencyis derived. It is shown that the optimization of the piezoelectric stack actuatorcan be decoupled from the topology optimization of the compliant mechanism.Computational verification of the analytical results is presented for two groundstructures modeled using frame elements. The trade-off between displacementamplification and maximization of the energy conversion efficiency is examined.